共有する
2025 年 42 巻 1 号 p. 3-21
September 30 - October 1, 2024
Nagoya, Japan
Azusa Kamikouchi (Nagoya University)
Satoshi Kojima (Korea Brain Research Institute)
Many animal species that form groups engage in communication between individuals through various sensory modalities. Among them, communication through auditory cues is utilized in various contexts, such as courtship, alarming, and more. In this symposium, we aim to delve into the significance and mechanisms of acoustic communication, spanning from humans to insects, in order to explore the conserved features as well as diversities in this form of communication.
S1-1 Acoustic communication in mosquitoesMatthew Su
1Inst. Adv. Res., Nagoya University 2Grad. Sch. Sci, Nagoya University 3ITbM, Nagoya University
S1-2 Functions and mechanisms of non-courtship song in songbirdsSatoshi Kojima
Sensory & Motor Systems Research Group, Korea Brain Research Institute
Birdsong is one of the most commonly observed animal vocal behaviors and has been extensively studied for a long time. While it is well known that birdsong produced in reproductive contexts functions for mate attraction and territorial defense, it remains unclear why birds sing outside reproductive contexts as well even when they are alone with no apparent recipients around. Moreover, songbirds of many species sing intensely in the early morning, a phenomenon widely known as the“dawn chorus (DC)”, but the functions and underlying mechanisms of the DC remain surprisingly elusive. Here, we provide experimental evidence that non-courtship song, including the DC, functions as vocal training to maintain the song production system in optimal conditions to prepare for song performance in reproductive contexts. We also studied the brain mechanisms underlying non-courtship song and identified neural circuits and neuromodulators responsible for regulating intrinsic motivation for non-courtship song. Our results revealed both ultimate and proximate factors of non-courtship song, greatly advancing the comprehensive understanding of vocal behaviors in animals.
S1-3 Sound communication in bat echolocation behaviorShizuko Hiryu
Faculty of Life and Medical Sciences, Doshisha University
While communication generally refers to vocal communication with others, echolocation of bats can be viewed as a form of ＂communication”with one’s echoes. In this presentation, I will introduce experimental data on the sound communication behavior of bats from the individual to the group level. For example, many bats can fly in tight spaces such as caves without colliding with each other. To correctly perceive their surroundings through echolocation, bats need to extract only their echoes from the complex mixture of ultrasounds belonging to neighboring conspecifics. Group flight experiments, in which individual bats were equipped with telemetry microphones, revealed that bats flying in groups avoid signal interference by slightly shifting the frequency of their ultrasounds. Furthermore, such frequency-adjusting behavior of bats is also effective in operating multiple robots equipped with ultrasonic sensing. This presentation will also demonstrate how bats use echolocation tactics while foraging and how they interact with other individuals during foraging. It will provide a broad perspective on sound-based communication in bats, spanning both ecological and engineering aspects.
S1-4 The signal function of infant crying in human developmentYuta Shinya
Grad. Sch. Edu., The Univ. Tokyo
Human infants are known to cry more frequently and intensely than other primates, raising questions about the evolutionary and functional significance of this behavior. Research has demonstrated that crying serves as an“honest signal”of an infant’s physiological state and trait, with acoustic analysis being used to understand various developmental conditions. This presentation will discuss the unique role of crying in the evolution of auditory communication and its importance in human language development. Specifically, we will highlight findings that suggest that infant crying contributes to the development of speech and social skills through facilitating infant-caregiver interactions. Additionally, we will explore recent efforts to apply deep learning techniques to analyze the acoustic features of infant cries, aiming to understand the developmental origins of language.
Masashi Tabuchi (Case Western Reserve University)
Yoshinori Suzuki (Nagoya City University)
Interoception is an endoreceptive process that monitors the internal state of the body and controls the internal drive to achieve homeostasis. Interoceptive neural processing serves not only as an important mechanism to promote adaptive responses through brain and interorgan communication but also plays a critical role in the higher-order functions of brain computation, providing motivational internal drives and regulating autonomic, cognitive, and behavioral functions. This symposium aims to provide an overview of current interoceptive neural information processing, especially from the perspective of comparative physiology and biochemistry, and to shape a place for knowledge synthesis from the unique perspective of comparative interoceptive neural information processing.
S2-1 The Interplay of Multi-Organ Coordination in Temperature Acclimatization of Caenorhabditis elegansAkane Ohta1, 2, Atushi Kuhara1, 2, 3
1Dept. Biol., Grad. Sch. Nat Sci, Konan Univ., 2Inst. Integral NeuroBiol., Konan Univ., 3AMED PRIME
To survive and reproduce, organisms must adapt to environmental changes, with temperature being a critical factor that affects essential biochemical reactions. To elucidate the mechanism of adaptation to temperature, we use the temperature-dependent cold tolerance and temperature acclimation of Caenorhabditis elegans as an experimental model (Ohta et al., Nat Commun, 2014, Motomura et al., PNAS, 2022). Cold tolerance is regulated by the nervous system, including thermosensory neurons, in coordination with the gut, sperm, and muscles. The gut, as the major fat storage organ, regulates fat mobilization and accumulation in a temperature-dependent manner, contributing to temperature acclimation. Normal spermatogenesis influences cold tolerance by modulating the responsiveness of thermosensory neurons. Additionally, PolyU-specific endoribonucleases expressed in muscle cells likely contribute to cold tolerance through a nonautonomous mechanism involving inter-tissue transport. Understanding cold tolerance and temperature acclimatization in C. elegans provides valuable insights into systemic physiological regulation in response to temperature changes.
S2-2 A neuronal system for seminal fluid replenishment in mated male DrosophilaRyo Hoshino1, Ryoya Tanaka2, Hsin-Kuang Lin3, Tomotsune Ameku2, Yuko Shimada-Niwa1, Azusa Kamikouchi2, Takeshi Awasaki4, Ryusuke Niwa1
1TARA, Univ. of Tsukuba 2Grad. Sch. Sci., Nagoya University 3Grad. Sch. Life Env. Sci., Univ. of Tsukuba 4Sch. Med., Kyorin University
In Drosophila melanogaster, a seminal fluid protein called Sex Peptide (SP), transferred from males to females during mating, drastically induces post-mating responses in females. After ejaculation, the amount of SP in male seminal fluid rapidly decreases, requiring males to replenish SP by increasing its production in the male accessory gland (MAG). However, the molecular mechanisms underlying SP replenishment are largely unknown. This study reveals that SP replenishment is regulated by a neuronal relay between the ejaculatory bulb (EB), ventral nerve cord (VNC), and MAG. The EB afferent neurons express the SP receptor (SPR). SP itself and SPR in EB are both essential for SP replenishment, raising the possibility that SPR+EB neurons sense SP as it passes through the EB during ejaculation. These neurons project to the caudal part of the VNC, near the cell bodies of MAG-projecting serotonergic neurons. Subsequently, serotonin released from these neurons induces SP transcription through serotonin receptors in the MAG. Our study shows that the SP-SPR-serotonin relay is crucial for SP replenishment and reproductive success in Drosophila.
S2-3 Middle-aged obesity is caused by age-related shortening of rat neuronal primary ciliaManami Oya, Kazuhiro Nakamura
Dept. Int. Physiol., Grad. Sch. Med., Nagoya University
In mammals, one of the interoceptive mechanisms that inform the brain of excess energy in the body is leptin-melanocortin signaling, an important anti-obesity pathway. In this signaling, the melanocortin 4 receptor (MC4R) in the hypothalamus mediates the reception of the signal to elicit anti-obesity responses: suppression of food intake and increase in energy expenditure. To explore a mechanism involving MC4R that regulates the central sensitivity to this interoceptive signal, we examined the localization of MC4R in the rat hypothalamus and found that MC4R localizes to neuronal primary cilia, an antenna-like structure. Interestingly, MC4R-bearing primary cilia shortened with age. Forced shortening of MC4R-bearing primary cilia in young rats using genetic techniques decreased the hypothalamic sensitivity to melanocortins and resulted in increased appetite and decreased energy expenditure, leading to obesity. These results demonstrate that the length of MC4R-bearing primary cilia in hypothalamic neurons determines the sensitivity to the interoceptive signal of satiety and that their age-related shortening strongly impacts energy homeostasis and leads to middle-aged obesity.
S2-4 Metaplastic neuronal state transition regulates species-specific interoceptive processing in DrosophilaDieu Linh Nguyen, Makenzie Anne Hopkins, Vaibhav Menon, Anupama Dahanukar, *Masashi Tabuchi
1Dept. Neurosci., Case Western Reserve University School of Med 2Dept. Entomology., UC Riverside
Emerging data suggest that interoceptive processing is highly specialized and species-specific. However, its neural basis and its relation to ecological specialization remain unknown. We characterize the mechanistic biophysical framework of species-specific interoceptive processing by comparing the electrophysiological properties of clock output and protein hunger dopamine neurons in D. melanogaster and D. sechellia. Our results show that D. sechellia has remarkably distinctive intrinsic membrane properties in these neurons compared to those of D. melanogaster, including unique rebound spike responses and distinct processes of synaptic plasticity formation in response to protein deprivation. We further define discrete states of temporal structures in these neuronal activities based on their kinetic rapidness and variability, finding that D. melanogaster neurons exhibit strong state persistence in a specific class, while D. sechellia neurons display frequent state transitions in response to protein deprivation. Taken together, our data reveal the metaplastic neuronal state transitions through which ecological specialization emerges to influence interoceptive processes.
Masamichi Ae, Sakiko Shiga
Graduate School of Science, Osaka University, Japan
Many insects have photoperiodism for seasonal adaptation. Several studies have suggested that expression of clock genes is required for the photoperiodic time-measurement system that measures day length. However, it is unclear where and how this system is functioning. In some fish and insects expression of cryptochrome or opsin genes photoperiodically differs in eyes. Based on these reports we hypothesized that the photoreceptor organs might have the time-measurement system, and examined the expression of photoreceptor and clock genes in the Bolwig organ (BO) of Sarcophaga similis larvae which show clear photoperiodism for controlling pupal diapause. In situ hybridization showed that period and Rhodopsin6 were expressed in the BO cells. RT-qPCR showed that period expression levels in the BO were significantly higher in long days than short days, although Rhodopsin6 expression was not photoperiodically different. These results showed that the BO cells express both photoreceptor and clock genes necessary for the time measurement system. The photoperiodic change in period expression suggests that this system may be operating in the BO of S. similis.
P1-2 A luciferin analogue improves the sensitivity of mouse liver imaging*Yukimasa Ikari1, Nobuo Kitada1, 4, Shojiro Maki1, 2, Tomoko Yoshikawa3, Atsushi Nakamura1, 2
1Dept. Engineering Sci., Univ. Electro Communications 2Center Neurosci. and Biomed. Engineering, Univ. Electro Communications
3Org. International Education Exchange, Univ. Toyama 4Coordinated Center for UEC Research Facilities, Univ. Electro Communications
Bioluminescence imaging, particularly firefly bioluminescence imaging, is widely used in life science research. However, the yellow-green light is not highly penetrable in biological tissues, and therefore the firefly bioluminescence is not suitable for deep-tissue imaging. To overcome this limitation, our group has developed a near-infrared luciferin analog“TokeOni”based on the firefly bioluminescence system. Unexpectedly, without the introduction of the luciferase gene, we have observed luminescence from the liver of mice in vivo when TokeOni was administered. This result suggests the potential for bioluminescence imaging of the liver that does not necessitate the introduction of luciferase genes. In this study, to identify luciferins with higher light emission, we screened analogues of firefly luciferin using our laboratory’s substrate library. As a result, we discovered a substrate that exhibited a luminescence intensity approximately 1.5-fold higher than that of TokeOni in mouse liver.
P1-3 Activity in larvae, pupae and adults of the black chafer Holotorichia parallera*Rintaro Nakamura, Sakiko Shiga
Dept. Biol. Sci., Grad. Sch. Sci., Osaka University
In general, most organisms exhibit circadian rhythm of approximately 24 hours in their behavior, metabolism, and physiological functions. The circadian clock plays an important role in driving the circadian rhythms to maintain harmony with the living environment. On the other hand, it has been reported that adults of Holotorichia parallera show the circabidian rhythm of 48 hours (Kawasaki et al., 2017). However, it is not known when this circabidian rhythm is acquired during the development of H. parallera, and the purpose of this study is to clarify this. In this study, I observed the behavior of 36 larvae and 19 pupae under DD conditions, and 19 newly eclosed adults under 12L12D conditions. The results showed that most individuals of H. parallera did not show a clear rhythm as larvae or pupae, but began to show a circabidian rhythm as young adults. In addition, some young adults began to show a clear circabidian rhythm after exhibiting a circadian-like rhythm. These findings suggest that H. parallera acquires circabidian rhythm in an early adult stage, and that H. parallera acquires circadian rhythm first and then it may change to the circabidian rhythm.
P1-4 An automated tracking method for observing natural behavior of medaka*Mayuna Sano1, Tomoki Yamashiro2, Masayuki Yoshida2, Toshifumi Kimura1
1Sch. Hum. Sci. Env., Uni. Hyogo 2Grad. Sch. Int. Sci. Life, Hiroshima Univ.
Medaka is used as a model organism in the field of drug discovery, and its behavioral tests are being used as a source of information. Although medaka are group-living organisms, their behaviors and strategies differ by individual, and detailed positional information must be obtained for each individual and each frame to observe their behaviors in detail. Obtaining this information requires considerable effort due to its complexity. we aim to develop a researcher-friendly behavior analysis system. In this presentation, we report on (1) individual detection procedures appropriate for certain research environments, and (2) methods for acquiring three-dimensional motion. In (1), we used YOLO, one of the object detection algorithms, for learning and detection, and studied appropriate learning methods. In (2), we constructed a prototype of a device that can observe three-dimensional behavior and attempted data acquisition methods.
P1-5 Analysis of the effects of Neurocalcin delta on photoreceptor responses in zebrafishKyosuke Saito1, Momoko Kishino2, Masahiro Ueda3, Shuji Tachibanaki4
1Department of Biological Sciences, Graduate School of Science, Osaka University., 2, 3Department of Biological Science Graduate School of Science, Osaka University., 4Division of Biology Department of Natural Science Jikei University School of Medicine
In the vertebrate retina, there are two types of visual photoreceptor cells: rods and cones. Rods mediate scotopic vision, while cones mediate photopic vision. In accordance with their respective functions, these two cells differ in both sensitivity and response duration. To explore the molecular mechanisms of the differences, we previously conducted proteomic studies to identify proteins exclusive to rods or cones and identified Neurocalcin δB (NCALDB) as a potential cone-specific candidate.
We confirmed NCALDB localization in zebrafish retinas through immunohistochemistry, showing its predominant presence in cone photoreceptors. This supports our hypothesis that NCALDB modulates cone photoresponses.
We then attempted to generate NCALDB-deficient mutants to understand its role in cones but failed to obtain homozygous mutants, indicating NCALDB may play roles in early development. Our RT-PCR analysis showed NCALDB expression precedes cone development, suggesting its involvement in development.
In the presentation, we will also report electrophysiological and behavioral results from heterozygous mutants and discuss NCALDB’s function in cones.
P1-6 Analysis of the molecular basis of the mushroom body development in the honey bee*Shuichi Kamata, Takeo Kubo, Hiroki Kohno
Dept. Biol Sci., Grad. Sch. Sci., The Univ. Tokyo
In honey bees, the mushroom bodies (MBs), a higher-order center of the insect brain, comprise three class I Kenyon cell (KC) subtypes: lKCs, mKCs, and sKCs. The increase in the number of KC subtypes has been suggested to be related to the behavioral evolution in Hymenoptera. To investigate the molecular basis underlying the increase of the number of KC subtypes by inter-specific comparison of MB development, we have been analyzing the molecular basis of MB development in the honey bee and identified pupal stages where each of KC subtypes are produced. Here, we proceeded to the analysis of the molecular developmental basis of honey bee MBs. We performed in situ hybridization of some genes identified by RNA-seq analysis of brains of pupae at the stage when each KC subtype is produced. The results suggested that some genes were expressed in a specific MB region in the pupal brain, where neuroblasts or immature KCs were supposed to exist, throughout all pupal stages when KC subtypes are produced, and could be marker genes of those cell types. Based on these results, we propose a model of the molecular and cellular basis of MB development in the honey bee.
P1-7 Analyzing female source localization behavior of adult male silkmoth, Bombyx mori, in terms of odor diffusion and electroannteogram signals*Ryoko Sekiwa1, Shunsuke Shigaki2 and Tatsuya Ibuki1
1Pgm. Elec. Eng., Grad. Sch. Sci. Tech., Meiji University 2Prin. Info. Rech. Div., NII
P1-8 Behavioral impacts of single-cell photoablation of cercal giant interneurons on wind-elicited escape behavior of crickets*Nweke Chinonso Peter1, Hikaru Suzuki1, Hikaru Chida1, Hiroto Ogawa2
1Biosys.Sci. Course, Grad.Sch. Life Sci., Hokkaido Univ. 2Dept. Biol. Sci., Fac. Sci., Hokkaido Univ.
Animals’ behavior depends on the stimuli triggering it and environmental conditions, both of which are detected by the sensory system. Stimulus information encoded as ascending signals is conveyed to higher integration centers, such as the brain. The behavioral functions of a specific neuron have been identified for descending“command”neurons, but it is still unclear for ascending neurons. We addressed this issue for the wind-elicited escape behavior in crickets because identified giant interneurons (GIs) are assumed to provide the ascending signals correlated with that behavior. Using single-cell photoablation techniques combined with intracellular recording, we selectively ablated a specific GI and examined the wind-elicited behavior before and after the ablation. The ablation of the Medial Giant Interneuron (MGI) reduced the response probability and prolonged the reaction time. The running distance and velocity decreased, but the escape direction was unaffected. In contrast, GI 10-2 ablation decreased the tuning toward the side ipsilateral to its soma and increased variability in the escape direction. These findings revealed that GIs have distinct roles in escape behavior.
P1-9 Biomechanics and neural circuit mechanisms for the pitch control in zebrafish*Takumi Sugioka, Masashi Tanimoto, Shin-ichi Higashijima
National Institute for Basic Biology
Postural maintenance is important for many animals. Biomechanics and neural mechanism for the postural control are, however, not fully understood. To unveil the mechanisms of the postural control, we used larval zebrafish, which have many advantages in neural circuit analysis. Fish correct body pitch angle by forward swimming. Through close observation of freely swimming fish, we noticed that they swam with the deflection of tail tip depending on the pitch angle change. The tail tip deflected dorsally/ventrally when fish swam upward/downward. We also found that fish exhibited a slight flexion of the rostral body in a pitch angle-dependent manner. The rostral body flexed dorsally/ventrally when the head tilted downward/upward. In a mechanical model of swimming, fish receive two forces that pitch fish body. 1) Swimming with the deflected tail tip pushes water, which generates propulsive force. 2) The tail deflection and rostral body flexion generate lift force during forward movement in water. Moreover, we revealed muscles and neural basis for the rostral body flexion. Together this work reveals biomechanics and neural mechanism underlying postural control in the pitch axis in fish.
P1-10 Characterization of the efferent neurons projecting to the retina in the medaka*Miyuu Hanasato, Sakie Terada, Emi Kawano-Yamashita
Grad. Sch. Hum. Sci., Nara Women’s Univ.
P1-11 Depth cues for mole crickets burrowingYuta Uchida, Noriyasu Ando
Dept. Life Eng., Maebashi Inst. Tech.
Subterranean animals use non-visual information to burrow underground, however, depth perception is still unknown. We hypothesized that oriental mole crickets Gryllotalpa orientalis use the temperature and hardness of the soil as depth cues, and investigated the relationship between those conditions and burrowing behavior. The effect of soil temperature was investigated using a thin observation tank filled with sphagnum moss in which Peltier elements were attached to the bottom to generate a temperature gradient that depended on the depth of the tank (the deeper the depth, the lower the temperature). In the experiment to change the soil hardness, the density of the sphagnum moss in the tank was changed. The results showed that the stay rate at the depth of the low temperature with the temperature gradient was smaller than that at the same depth without the gradient. Furthermore, the depth of burrows tended to be shallower with the temperature gradient. We will further investigate the soil temperature and hardness in a natural habitat and discuss the potential cues for depth perception underground.
P1-12 Detailed analysis of the walking patterns in pillbugs, Armadilidium vulgareK. Nakajima, R. Araki, N. Nagaya
Grad. Sch. Frontier Informatics, Kyoto Sangyo University
Measuring leg movement data in arthropods has been challenging, making detailed analysis of each leg’s gait difficult. Our study aimed to investigate the periodicity and interlocking of leg movement by analyzing three-dimensional motion data. To achieve this, we used the tethered method to fix five target pillbugs and filmed them for 25 seconds. We then utilized DeepLabCut, a posture estimation tool, to obtain high-accuracy motion data for all 14 legs through machine learning. After preprocessing the acquired data, we transformed it into a more manageable format for analysis. Our analysis of the autocorrelation and cross-correlation of the processed data for the tips of all legs revealed a moderate correlation. Interestingly, when we examined a shorter section, we found a more significant correlation than the analysis of the entire data set. These moderate correlations suggest periodic and interlocking leg movement in multipods. However, we acknowledge the limitations of the tethered method in identifying the target movement, and we are considering motion compensation analysis for future research.
P1-13 Development of a portable odor detection device using insect electroantennogram*Yuya Hirano1, Takeshi Sakurai2, Noriyasu Ando1
1Dept. Life Eng., Maebashi Inst. Tech, 2Fac. Agric., Tokyo Univ. Agric.
Odor detection using living organisms is playing an important role in society. Insects have an excellent ability to detect odorants and are potential candidates for odor sensors. The odor response of insect antennae is measured as an electroantennogram (EAG). however, the measurement requires electrophysiological equipment and experimental skills. To make the EAG measurement easier particularly for non-experts, we have been developing a portable EAG measurement device. We reported the characteristics of the EAG response of hawkmoths (Agrius convolvuli) to flow speed, adult age, and laterality, and the concept of the device at the last JSCPB annual meeting. Here we developed a prototype of the portable EAG measurement device by miniaturizing components and integrating them into a palm-top size. Inspired by mammalian sniffing, a hand bellows pump suctioned the odor (conspecific sex pheromone), and the odor was delivered to the isolated antenna inside the device, which increased EAG odor response as the flow speed increased. The operation of EAG measurement using our device is easy for non-experts and we also report an example of an odor detection task in a real situation.
P1-14 Development of toolkit for optogenetic manipulation and calcium imaging of medaka neural activity*Takahide Seki1, Kazuhiro Miyanari2, Asuka Shiraishi2, Sachiko Tsuda2, Satoshi Ansai3, Hideaki Takeuchi1
1Grad. Sch. Life. Sci., Tohoku University 2Grad. Sch. Sci. and Eng., Saitama University 3Ushimado Marine Institute, Grad. Sch. Nat. Sci. and Tec., Okayama University
Medaka (Oryzias latipes) has emerged as a valuable model in social neuroscience due to its diverse social behaviors. In this study, we successfully applied optogenetic and calcium imaging tools in medaka. First, we investigated the in vivo efficacy of the blue light-sensitive channelrhodopsin CoChR in medaka. Using CRISPR knock-in (KI) technology, we selected isl1 as the KI target gene and generated a KI line expressing CoChR in motor neurons. The KI line exhibited pectoral fin movements upon blue light stimuli. Next, to establish calcium imaging techniques in the medaka brain, we generated a transgenic line expressing the calcium indicator jGCaMP7s throughout the brain using Ac/Ds transposon system and a gap43 promoter (pan-neuronal marker). Using this strain, we conducted calcium imaging during visual stimuli. For visual stimuli, a swimming Paramecium or a moving light resource were presented and as previously reported in zebrafish studies, calcium signal spots appeared and moved in the optic tectum, corresponding to stimulus movements. These tools are expected to advance our understanding of neural mechanisms underlying social behaviors.
P1-15 Discontinuous Visual Stimuli May Enhance Learning in AntsAkihiro Takahara, Tomoko Sakiyama
Grad. Sch. Sci. Eng, Soka Univ.
relationship between a visual landmark and ant locomotion. Specifically, we employed Japanese carpenter ants and initiated the experiment by introducing individuals into ANTAM. In the first experiment, individual ants in ANTAM were allowed to walk freely for 40 seconds following a 20-second feeding period. Throughout both feeding and walking, a landmark was positioned in front of the ants. This landmark remained constantly projected on the monitor and did not change during the 1-minute training period. After this training, the ants were transferred to a Y-shaped maze. The Y-shaped maze also featured a landmark of the same shape and color, affixed to one of the three arms. We assessed whether the ants moved towards the landmark during their initial movement. Conversely, in the second experiment, the landmark flickered at regular intervals of one second for 40 seconds following feeding during the training. The test in the second experiment mirrored that of the first. In the results, ants in the second experiment were more likely to approach the landmark during the test compared to those in the first experiment.
P1-16 Dopamine-mediated modulation of sound processing in fruit flies*Haruna Yamakoshi, Mihoko Horigome, Noiri Oguri, Ryoya Tanaka, Takuro Ohashi, Yuki Ishikawa, Azusa Kamikouchi
Dept. Bio. Sci., Nagoya Univ.
The internal states such as arousal and attention often modulate sensory processing in the brain. However, how this modulation is achieved remains obscure. To elucidate this question, we focused on the auditory response of fruit flies. During mating rituals, females evaluate“courtship songs”produced by males, deciding whether to mate or not. We hypothesized that sound processing in females is modulated by their internal states via dopamine, which is involved in the internal state-dependent modulation of sensory processing in various animals. Our immunohistochemistry and single-nucleus RNA-seq data analyses revealed that primary auditory neurons express several types of dopamine receptors. Transsynaptic analysis revealed that some primary auditory neurons receive direct synaptic inputs from dopaminergic neurons. Knockdown of one of dopamine receptors in primary auditory neurons reduced their calcium responses to sound in virgin females, as well as the flies’ song response behaviors. The phenotype of calcium response reductions did not occur in mated females, together suggesting the involvement of dopamine in modulating sound processing depending on mating status of female flies.
P1-17 Effects of food rearrangement on decision making in ant populationsRyo Sakata,Tomoko Sakiyama
Dept. Info. Sys. Sci. Soka Univ.
In this study, we examined the relationship between food placement and the collective behavior of ants within an open field. Here, the nests of garden ants were used to connect to the field. Two types of experiments were conducted: In the first experiment, food was placed at one of two predetermined points in the field, and the position of the food was switched every 10 minutes for one hour. We examined whether the ants could response to the change of food position when the food position was changed while the ants were forming an ant trail. On the other hand, in the second experiment, the ants were observed for one hour with the food placed at both of the same two points as in the first experiment. The results showed that in the first experiment, the ants responded to the changes in the position of the food to some extent, while in the second experiment, the ants tended to concentrate on one of the two food points. These results suggest that a group of ants can utilize one food source while behaving adaptively as a group to changes in the environment.
P1-18 Elucidating the mechanism whereby larval intake of specific fatty acids enhances adult cold tolerance in Drosophila melanogaster*Honoka Morioka1, 2, Yusuke Hara2, Daisuke Yamamoto2, Kosei Sato1, 2
1Dept. Life Sci., Grad. Sch. Sci., Univ. Hyogo 2Adv. ICT Res. Inst., NICT
In D. melanogaster, adult females are known to prefer a yeast-rich diet, but at low temperatures, the preference changes so that they favor a plant-based diet rich in unsaturated fatty acids (FAs). Flies fed on the plant diet are more cold tolerant than those fed on the yeast-rich diet. However, it remains unknown whether any specific FAs are involved in the enhancement of cold tolerance. Here, we studied the cold tolerance of flies reared on synthetic media differing only in FA compositions, and identified two FAs that can enhance adult cold tolerance when ingested. Systemic, heterologous expression of FAT2, a C. elegans desaturase that mediates the synthesis of one of the two FAs, similarly enhanced cold tolerance of flies without FA feeding. We also found that larval intake of FAs was critical for enhancing adult cold tolerance. Lipidome analysis revealed that the FA composition of adult phospholipids correlated with the FA composition of the larval diet. Female preference for plant diet would thus contribute to the acclimatization of their offspring to seasonal cold stress by enhancing cold tolerance through the ingestion of the specific FAs.
P1-19 Enhanced sleep in Drosophila melanogaster under the presence of predators*Haruki Kato1, Namiki Shima1, 2, Yoshinori Suzuki1, Jun Tomita1, Kazuhiko Kume1
1Dept. of Neuropharmacology., Grad. Sch. pharmaceutical Sci., Nagoya City University 2Dept. of Intelligent Systems, Grad. Sch. Informatics., Nagoya University
Sleep is generally considered a disadvantage for survival due to immobility and reduced response to external stimuli. Recent research has revealed the preservation of sleep even in species lacking a central brain, such as hydra, suggesting physiological role for sleep beyond advanced brain functions. We hypothesize that a state of quiescence is an adaptive behavior for small organisms during periods not dedicated to activities like feeding and reproduction, and that immobility itself constitutes a part of sleep functions. This study aims to elucidate the role of immobility during sleep in Drosophila melanogaster by using the jumping spider, a natural predator of fruit fly. Flies exposed to the spider showed increased sleep. Furthermore, we recently found that a similar phenotype was observed by spider odor. These data suggest that flies do not simply respond to spider movement but recognize predator cues and increase their immobility. Additionally, to explore the impact of the sleep-wake states of flies on their susceptibility to predation, we present spiders with flies whose mobility or immobility is optogenetically induced, recording changes in predatory behavior.
P1-20 Estimation of the vertical position of the zebrafish in novel-tank test using electrical ventilation signals for evaluation of emotional statesHitomi Sasaki1, Masayuki Yoshida1, Zu Soh2
1Graduate School of Integrated Sciences for Life, Hiroshima University 2Graduate School of Advanced Science and Engineering, Hiroshima University
Recently, we have developed a technique to record ventilation-related electrical signals from free-swimming zebrafish, enabling simultaneous monitoring of behavioral and physiological (i.e. ventilation) responses to various challenges. However, an observation arena of the previously reported method required to be shallow (typically, 30mm) due to technical limitations for accurate estimation of movements and ventilations. Therefore, using this method, movements of the fish were partially restricted in the horizontal plane. In the present study, we succeeded to improve the previous method to enable the observation of behavior and ventilation of the subject fish moving in the vertical plane as well, enhancing evaluation of emotional states of the fish. We estimated the vertical positions of a fish based on the differences in ventilatory-signal strengths recorded from multiple electrodes placed at various depth in the“deep”(160mm) aquarium. It was suggested that the present method is more information rich compared with the previous one in the situation of novel-tank tests.
P1-21 Examination of medium conditions for primary cell culture of the pond snail (Lymnaea stagnalis)*Miku Kato1, Kengo Namiki1, Naoki Hatashita1, Emiko Hayama2, Etsuro Ito1
1Dept. Biol. Waseda Univ., 2Dept. Pediatric Cardiology. TWM Univ.
The pond snail (Lymnaea stagnalis) is a good model for studies of developmental biology and learning memory mechanism, but the understanding of gene function is limited by the lack of establishment of genome editing. Therefore, we should first develop the primary cell culture technique for Lymnaea, because cell culture technique is needed as an effective tool for genetic manipulation such as transfection. In the present study, the conditions for primary cell culture were investigated. We mimicked the methods for Biomphalaria, which belongs to the same plumonate as Lymnaea, for trochophore stage embryonic cells. Primary cell culture was successfully maintained for up to 38 days using the medium containing some components of Schneider’s Drosophila medium and 10% FBS, adjusted to pH 8. We focused on cells adhering to culture dishes because they were easy to observe, so we cultured cells in glass-bottom dishes coated with different types of coatings and checked the double-stained actin and nucleus. Cells were observed to adhere well to the collagen-coated glass surface, the shape of which was fibroblast-like. These cells were relatively flat with a size of about 50 µm.
P1-22 Exploration of the amino acids metabolism after blood feeding in yellow fever mosquito, aegypti*Yusuke Kato1, 2, Ayano Oi1, 2, Fumiaki Obata1, 2, Chisako Sakuma1, 2
1RIKEN BDR 2Dept. Animal Dev. Physiol., Grad. Sch. Bio., Kyoto University
P1-23 Foregut Piezo neurons convey sugar aversion in fed Drosophila*Nobuhiro Takahashi1, 2, Hiromu Tanimoto1, Nobuhiro Yamagata2
1Grad. Sch. Life. Sci., Tohoku. Univ 2Grad. Sch. Eng. Sci., Akita Univ
A fundamental shift in neuroscience suggests a bidirectional interaction of the gut with the healthy and dysfunctional brain. This holds true in the memory process, such that the etiology of memory disorders, including Alzheimer’s disease, is coupled with intestinal malfunction. However, neuronal correlates linking the brain and gut, thus delineating the“mnemonic”gut-brain axis, remain largely elusive. Here, we found that food-satiated flies exhibit odor-sugar aversive memory, starkly contrasting to starved flies forming appetitive memory. The degree of aversive memory was correlated with the amount of sugar stored in the abdomen. We found that Piezo, the mechanosensory cation channel, was required for the aversive memory. Crop-innervating Piezo neurons monitored sugar ingestion in a Piezo-dependent manner, neurotransmission from which was necessary for sugar aversive memory. We thus concluded that Piezo-mediated interoception underlies sugar aversive reinforcement. Since aversive PPL1 dopamine neurons in the brain were essential for the sugar aversive memory, we propose a gut-brain axis for state-dependent sugar reinforcement.
P1-24 GABAergic regulations in the auditory neural circuit in D. melanogasterNoiri Oguri*, Ryuya Okamoto, Azusa Kamikouchi
Dept. Biol. Sci., Grad. Sch. Sci., Nagoya University
Many animals use species-specific sounds during courtship. There, the receiver animal evaluates the sound signals from the sender one to decide whether to accept mating. However, the detailed underlying mechanisms that process auditory information have not yet been elucidated. To tackle this question, we focused on D.melanogaster as they use courtship songs during the mating ritual. Previous studies have identified AMMC-B1 neurons, secondary auditory neurons in the brain necessary to the song response behavior of female flies. In this study, we classified AMMC-B1 neurons into two subtypes, having different projection patterns and frequency response properties. These AMMC-B1 subtypes are connected via GABAergic local interneurons. Interestingly, these GABAergic neurons respond specifically to a low-frequency pure tone, without responding to courtship song. The neural-circuit architecture comprised of these GABAergic neurons and the two AMMC-B1 subtypes, together with their response properties, suggests that the response of AMMC-B1 neurons to low-frequency sounds is suppressed by these GABAergic neurons. This inhibition may ensure a robust behavioral response to courtship songs.
P1-25 Genes involved in heat tolerance diversity in plants are required for heat and cold tolerance in C. elegansSakura Sengoku1, Akane Ohta1, 2, 3, Teruaki Taji4, Atsushi Kuhara1, 2, 3, 5
1Faculty of Science and Engineering, Konan University, 2Graduate School of Natural Science, Konan University, 3Institute for Integrative Neurobiology, Konan University, 4Department of Bioscience, Tokyo University of Agriculture, 5AMED-PRIME, Japan Agency for Medical Research and Development.
Adaptation to temperature changes is an essential ability for animals and plants to survive and proliferate. Taji et al found responsible genes for diversity of heat tolerance in Arabidopsis thaliana (unpublished). We show here that a nematode homolog of its plant gene, snrp, encoding small nuclear ribonucleoprotein is involved in heat and cold tolerance in C. elegans. SNRNP is conserved from plants to humans, and human homologue SNRNP is suggested to be involved in mRNA splicing function. We found that snrp mutant showed enhanced cold tolerance after grown at 20℃, and showed significantly decreased heat tolerance after grown at 20℃ suggesting that SNRP is involved in both cold and heat tolerance of C. elegans. SNRP is expressed in most of tissues of the C. elegans body, and single cell RNA-seq data of C. elegans indicates that SNRP expresses in many neurons including thermosensory neurons. These suggest that SNRP may regulate heat and cold tolerance via regulating splicing in unidentified genes, therefore we are planning to investigate the effects of SNRP-mediated regulation of gene expression on temperature tolerance.
P1-26 Histological feature of the deep brain photoreceptor projecting to the retina in the lamprey*Haruka Sasada, Satoshi Tamotsu, Emi Kawano-Yamashita
Grad. Sch. Hum. Sci., Nara Women’s Univ.
P1-27 Hybrid top-down behavioral tracking using UMATracker and DeepLabCut*Yusuke Notomi, Shigeto Dobata
Dept. Gen. Sys. Stu., Grad. Sch. Arts, Sci., The Univ. Tokyo
Recent advancements in information processing technology have enhanced the automation of behavioral analysis with improved data acquisition efficiency. However, in experimental video analysis, the goal is maximizing accuracy through precise error correction with minimal effort, which could be achieved by utilizing more than one automated tool. Here, we propose a two-stage top-down approach which combines two tracking software: UMATracker for robust background subtraction and object detection, and DeepLabCut for pose estimation in small windows, followed by automated error correction. We tracked the ant Camponotus japonicus, known for its size and morphological diversity, in various behavioral contexts with complex posture changes like swimming, walking, and grooming. Therefore, our method was designed to be robust for diverse species and experiments, demonstrating accurate estimation. Additionally, we significantly reduced computational resource requirements, making it effective on low-spec PCs. Finally, we applied this method to challenging scenarios with multiple workers, and it demonstrated accurate individual separation, tracking, and high-precision pose estimation.
P1-28 Identification of α, β-trehalose as a key substance for dormancy in resting cysts of colpodid ciliates, including comparative analysis with other multicellular organisms1, 2*Shuntaro Hakozaki, 3Makoto Ogata, 1Yuta Saito, 1, 4Ryota Saito, 5Tomohiro Suzuki, 6Futoshi Suizu, 7Yasutsugu Suzuki, 1Taichi Kimura, 7Kozo Watanabe, 1Yoichiro Sogame
1Dept. Appl. Chem. Biochem, NIT. Fukushima College 2Fac. Symbio. Sys. Sci., Fukushima Univ. 3Fac. Food. Agri. Sci., Fukushima Univ. 4Dept. Chem. Biotech., Kochi Univ. 5Cent. Biosci. Res. Edu., Utsunomiya Univ. 6Fac. Med. Kagawa Univ. 7CMES. Ehime Univ.
P1-29 Involvement of the intermediate nidopallium in viscerosensory mechanism in birdsChisato Yatsuda, Ei-Ichi Izawa
Dept. Psychol., Grad. Sch. Human Relat, Keio University
Viscerosensory circuits play an important role in social cognition and emotion in mammals including humans. The viscerosensory signals ascend to the parabrachial nucleus (PB) directly from the dorsal horn of the spinal cord and indirectly from the nucleus of the solitary tract (nTS) of the brain stem and, then reach the anterior cingulate and the insular cortices via the thalamus. Although neuroanatomical studies have suggested similar viscerosensory circuits in avian brains which evolved with non-laminar structures in the pallium, no study has yet reported brain regions, especially the pallium, involved in viscerosensory processing. This study examined viscerosensory brain regions of large-billed crows (Corvus macrorhynchos) by measuring the expression of an immediate-early gene protein Egr-1, as a neural activity maker, associated with visceral stimulation by LiCl i.p. injection. We found significantly more immunoreactive neurons in the intermediate nidopallium, the dorsomedial PB and the nTS of LiCl-injected birds than of saline-injected ones. These results suggest that the NI may be involved in viscerosensory processing in the avian pallium.
P1-30 Knockout of wrn gene mutant in zebrafish causes premature malnutrition*Kota Ujibe1, Makoto Kashima2, Rintaro Shimada1, Masashige Okamoto1, Isao Kobayashi3, Seiji Wada1, Hiroki Matsuda4, Akira Sakamoto1, Hiromi Hirata1
1Aoyama Gakuin University., 2Toho University., 3Kanawaza University., 4Ritsumeikan University
Werner syndrome (WS) is a progeria that shows aging symptoms around twenty. However, childhood-onset syndromic signs have not been investigated. We generated a mutant zebrafish of wrn, a responsible gene for WS, and found that about 90% of the mutant underwent premature death at 7～21 days post fertilization (dpf). We employed time-course individual RNA-Seq using 4～35 dpf larvae to elucidate what occurs in the mutant. Based on gene expression profiles, premature death mutants showed decreased expression of pancreatic exocrine cell markers and increased expression of DNA damage markers. By using transgenic zebrafish that labeled pancreas, we observed pancreatic abnormality in a part of mutant. In these abnormal mutants, cell death occurred in not only pancreas but also intestine and skin. Interestingly, histological analysis revealed that abnormal mutants defected intestinal villi. Furthermore, the amounts of glycogen, glucose and fat in abnormal mutants were lower than wild-type. These results revealed that premature death mutant undergo death by malnutrition due to pancreatic exocrine defect. Our results propose a possibility that malnutrition occurs also in human WS childhood.
P1-31 Metabolism at a social level: king- and queen-specific degradation of uric acid contributes to reproduction in termites*Takao Konishi1, 2, Eisuke Tasaki1, 3, Mamoru Takata1, Kenji Matsuura1
1Grad. Sch. Agric., Kyoto Univ. 2Dept. For. Entomol., FFPRI 3Dept. Biol., Fac. Sci., Niigata Univ.
Caste-based reproductive division of labor in social insects is built on asymmetries in resource distribution within colonies. Kings and queens dominantly consume limited resources for reproduction, while non-reproductive castes such as workers and soldiers help reproductive castes. Studying the regulation of such asymmetries in resource distribution is crucial for understanding the maintenance of social systems in insects, although the molecular background is poorly understood. We focused on nitrogen compounds, the key to reproduction requiring protein synthesis. We found that king- and queen-specific degradation of uric acid (a major product of nitrogen metabolism) contributes to reproduction in the subterranean termite Reticulitermes speratus. The urate oxidase gene, which catalyzes the uric acid degradation, was highly expressed in mature kings and queens. Suppression of uric acid degradation decreased the number of eggs laid per queen. Uric acid was shown to be provided by workers to reproductive castes. Our results indicate that king- and queen-limited capability to use certain compounds enables colony resources to concentrate in reproductive castes.
P1-32 Multi-thermosensation through multiple qualitatively different thermoreceptor in cold tolrerance of C. elegansNanako Kanamura1, Akane Ohta1-3, Yuki Sato2, 3, Akira Kawanabe4, Yuichiro Fujiwara4, 5, Atsushi Kuhara1-3, 6
1Dept. Biol. Facul. Sci & Engineer. Konan Univ. 2Dept.Biol. Grad. Sch. Sci. Konan Univ. 3Inst. of Integral NeuroBiol. Konan Univ. 4Faculty of Medicine, Kagawa University, Kagawa. 5Graduate School of Biomedical and Health Sciences (Medical), Hiroshima University. 6PRIME AMED
Sensing environment and responding appropriately are essential for organisms. We are using cold tolerance of C. elegans, as a model of studying thermo-sensation. We previously identified ASG, ADL, and ASJ thermosensory neurons involved in cold tolerance, in which G-protein coupled receptor (GPCR) and Degenerin/Epithelial Sodium Channel (DEG/ENaC) DEG-1 act as thermo-receptor (Ohnishi et al., Nat commn, 2024; Ohta et al., Nat commn, 2014; Takagaki et al., EMBO rep., 2020). Here we aim to clarify whether GPCR and DEG/ENaC cooperates with thermo-sensation in single sensoryneuron. We found that UNC-8 and DEG-1 positively regulate cold tolerance after 20℃ rearing. By electrophysiological analysis, UNC-8 and DEG-1 expressed in Xenopus oocytes showed Na+ influx at 29℃, and co-expression of UNC-8 and DEG-1 showed a similar Na+ influx, suggesting that these form a hetero-channel in thermo-sensation. Recent single cell transcriptome analysis ellucidated that both UNC-8 and DEG-1 are expressed in ADL. Because TRP channels and GPCR acts as thermo-receptor in ADL, we are attempting to investigate whether DEG/ENaC is the third thermoreceptors in ADL.
P1-33 Navigation behavior of crickets using auditory and polarization vision*Taisuke Ito1, Nobuaki Matsubara2, Midori Sakura2, Hiroto Ogawa3, Noriyasu Ando1
1Dept. Life. Eng., Maebashi Inst. Tech., 2Dept. Biol., Grad. Sch. Sci., Kobe Univ., 3Dept. Biol. Sci., Fac. Sci., Hokkaido Univ.
Phonotaxis in female crickets is known to be a reflexive behavior in response to the conspecific male calling song. On the other hand, crickets also have polarization vision in their dorsal compound eyes and exhibit orientation behavior in response to the orientation of the electric vector (e-vector) in polarized light. We hypothesized that by associating the direction of the sound source to e-vector orientation, the phonotaxis could be more redundant. To test this hypothesis, we developed a virtual reality system that can present auditory and polarized light stimuli to tethered walking crickets (Gryllus bimaculatus) on a spherical treadmill. As a preliminary experiment, we analyzed the change of body orientation of female crickets in response to e-vector orientation and the calling song in open-loop condition. The results showed that female crickets in the presence of the calling song emitted above them responded significantly higher to e-vector orientation than those without the song, suggesting that the behavior state triggered by the calling song may enhance the response to polarized light. We will further conduct a closed-loop experiment to associate these two modalities.
P1-34 Analyzing the behavioral modulation mechanism of an adult male silk moth caused by antennal lostKeisuke Yokota, Shunsuke Shigaki
Osaka University Graduate School of Engineering Science
In this study, we investigate the robust sensorimotor integration mechanisms of an insect when losing its part of the body, focusing on the female localization behavior of an adult male silk moth, Bombyx mori. When the silk moth receives female sex pheromones with its antennae, it elicits a stereotyped behavior pattern called the mating dance. Despite the loss of a body part, it can robustly localize by modulating its behavior. Therefore, we measured how the silk moth behaves when it has two antennae and when one antenna is lost. Experimental results showed that the silk moth achieved a localization success rate of 100% with both antennae intact, and 80% even with one antenna lost. This suggests that a silk moth that has lost one antenna has the ability to localize. Furthermore, by analyzing its neck movements using insect Virtual Reality, we found that the silk moth tends to tilt its head towards the side of the missing antenna over time. This suggests that when one antenna is lost, the silk moth modulates its behavior to effectively acquire odor information from its environment.
P1-35 Neuromuscular control of abdominal movement in hawkmoth flight*Yuji Motegi, Noriyasu Ando
Dept. Life Eng., Maebashi Inst Tech.
Hawkmoths have excellent maneuverability such as sharp turns and hovering. The abdominal movement, as well as wing flapping, is thought to be involved in maneuverability during flight, and previous studies have suggested that hawkmoths use abdominal movement to change the direction of thrust and control flight. However, the control mechanism of the abdomen is still unknown. In this study, we analyzed the electromyogram (EMG) of the dorsal longitudinal muscle (DLM) in the first abdominal segment in hawkmoths (Agrius convolvuli). The EMG of the abdominal DLM showed burst-like spikes in association with the elevation of the abdomen. However, we found that the spike bursts occurred intermittently with each wingstroke cycle, indicating that the activity of the abdominal DLM is controlled at each stroke cycle and is tightly coupled with the wing motor pattern. Our results suggested the existence of a common intersegmental oscillation cycle that controls both wing flapping and abdominal movements.
P1-36 Neurotransmission pathways of ejaculation-inducing neurons’ downstream in D.melanogaster male*Haruka Ando1, Hayato M Yamanouchi1, Ryoya Tanaka1, Azusa Kamikouchi1
1Division of Biological Science, Graduate School of Science, Nagoya University
Ejaculation is a necessary step in the transfer of sperm from the male to the female in many sexually reproducing animals. In D. melanogaster, previous studies suggested that ejaculation-inducing neurons (crz neurons) release the neuropeptide corazonin (Crz), which activates downstream neural circuits to induce ejaculation. However, actual neurotransmission pathway under crz neurons is unclear. Here, we aim to identify the neurotransmission pathways under crz neurons using genetic tools in D. mel. First, to evaluate whether Crz signaling is necessary for inducing ejaculation, we observed the fertility of males with defects in Crz production. Surprisingly, these males showed fertility, suggesting that the male ejaculates during copulation without Crz signals. Second, we observed the fertility of males that suppressed the chemical synapse of crz neurons using genetic methods that ectopically express neurotoxins, TNT. The result of this experiment suggests non-chemical neurotransmission under crz neuron may be involved in ejaculation.
P1-37 Non mitochondrial function of HADH is required for temperature acclimation of C. elegansYukina Mori1, Misaki Okahata1, Akihisa Fukumoto1, Toru Miura1, Yohei Minakuchi2, Atsushi Toyoda2, Akane Ohta1, Atsushi Kuhara1, 3
1Faculty of Science and Engineering Konan University & Institute for Integrative Neurobiology, Kobe, Japan, 2National Institute of Genetics, Japan, 3PRIME, AMED
To understand the molecular mechanisms of temperature acclimation of animals, we are utilizing temperature acclimation of nematode C. elegans. In this study, we used RNA sequencing analysis to identify novel genes regulating temperature acclimation. We isolated the hadh gene encoding a C. elegans homolog of human HADH, which catalyzes fatty acid β-oxidation in mitochondria as 3-hydroxyacyl CoA dehydrogenase. We found that C. elegans hadh mutant showed abnormal temperature acclimation, slowly acclimate to new temperature. Expression of HADH::GFP under hadh promoter was observed in neurons in the head and intestine of C. elegans. Tissue specific rescue experiment of hadh mutant suggests that HADH regulate temperature acclimation in neurons. Also, cell specific knockdown of the hadh gene in four neurons of wild-type exhibited an abnormal temperature acclimation similar to that of hadh mutant. Unexpectedly, HADH was strongly localized at nucleus, and its nuclear localization could be dependent on cultivation temperature. We are planning to introduce RNA sequencing for isolation of related-genes of nuclear HADH-dependent temperature acclimation.
P1-38 Parkinsonism-related gene “trpm7”-deficient zebrafish show reduced motility in free movement*Kenta Watai1, Kenichiro Sadamitsu1, Makoto Kashima2, Seiji Wada1 and Hiromi Hirata1
1Aoyama Gakuin University 2Toho University
TRPM7 is a member of Transient Receptor Potential Melastatin family of cation channels. trpm7-deficient zebrafish cause transiently touch-unresponsive phenotype at 2 days post-fertilization (dpf), while wild-type embryos exhibit escape behavior in response to touch stimuli. This touch-unresponsive behavior is also reported to recover and mutants respond to touch stimuli by 5 dpf. However, the swimming behavior from 5 dpf has not been thoroughly uncovered. In this study, we obtained a novel allele of trpm7 mutant causing an I756N amino acid substitution in the first transmembrane and analyzed their behavior at 5 dpf. trpm7 mutants showed short swimming distance and low swimming velocity compared to wild-type larvae. TRPM7 gene has been supposed as a genetic factor of local Parkinson’s disease in Western Pacific Islands of Guam and Rota. A previous study of the other trpm7 mutant allele reported a reduction of dopaminergic neurons. Collectively, our findings of trpm7 mutants support a link between reduced motility phenotype of trpm7 mutants and compromised motility symptom of Parkinson’s disease.
P1-39 Quantification of dark/light preference of loach individuals by semi-automated measurementsYuki Yoshikawa, Keiko Okano, Toshiyuki Okano
Dept. Elect. Eng. Biosci., Grad. Sch. Adv. Sci. Eng., Waseda Univ.
P1-40 Quantitative observation of the behavioral sleep in cleaner fish Labroides dimidiatusAtsuki Izumi1, Masayuki Yoshida1, Masanori Kohda2, Shumpei Sogawa2, Satoshi Awata*2
1Grad. Sch. of Integrated Sci. for Life, Hiroshima Uni. 2Grad. Sch. of Sci., Osaka Metropolitan Uni.
The cleaner fish is Labroides dimidiatus a diurnal fish and rests during night in a specific shelter. They also show characteristic behavioral sleep in laboratory conditions. Using an IR camera, we recorded the behavior of the cleaner fish during the dark period in their home tank, and analyzed the temporal patterns of body and eye movements, yawning-like activity, and the ventilation frequency. They showed periodical slow undulating movements which coincided with temporary decrease in the ventilation frequency at intervals around 5-20 min. Rapid eye movements (REMs) were also observed, although the intervals between the episode didn’t appear to be stable. We’ve found, however, the REM episodes were relatively scarce during the first half of the dark period and increased toward dawn. The yawning-like activity was also increased as the dark period approached its ending. The present results indicate that the behavioral sleep of the cleaner fish composed of characteristic movements or activities that show specific and periodic patterns of manifestations. The present study would contribute to understanding the similarities, differences, and the origin of sleep among vertebrates.
P1-41 Sexual dimorphism in auditory representation in yellow fever mosquito brainTakuro S. Ohashi1, 2, Yifeng Y.J. Xu1, 2, Shunsuke Shigaki3, Yukiko Nakamura1, 2, Tai-Ting Lee1, 2, YuMin M. Loh1, 2, Daniel F. Eberl4, Matthew P. Su1, 2, 5, Azusa Kamikouchi1, 2, 5
1Grad. Sch. Sci., Nagoya Univ., 2WPI-ITbM, Nagoya Univ., 3Prin. Inf. Res. Div., NII, 4Dept. Bio., Univ. Iowa, 5IAR, Nagoya Univ.
Sexual dimorphism in auditory behavior is an important component of courtship in many animals. Insights into sexual dimorphisms in central sensory processing for sex-specific behaviors in certain model organisms. The yellow fever mosquito Aedes aegypti, a major vector of various diseases, also shows sexual dimorphisms in hearing behaviors, with male attraction to sounds playing a key role in mating behavior. On the other hand, females do not appear to be attracted to male flight sounds. To investigate sexual dimorphisms in acoustic behaviors, previous reports have largely focused on differences in mosquito peripheral ear anatomy and function. Here, we used a combination of neuro-tracing, calcium imaging, and molecular analyses to examine sexual dimorphisms in auditory processing in the Ae. aegypti. We identified dimorphic neurons connecting male and female ears to the primary auditory processing center in the brain, and defined multiple distinct neuronal clusters based on responses to auditory stimulation. We finally used multi-omics analyses to investigate the molecular factors underlying these differences, with motile ciliary-related terms significantly enriched in males.
P1-42 Species differences of grouping behaviors and its neural mechanism in DrosophilaTomoka Nozaki1, Hiroaki Kawashima2, Hayato M Yamanouchi1, Azusa Kamikouchi1, Ryoya Tanaka1
1Grad. Sch. Biol. Sci., Nagoya University 2Grad. Sch. Info. Sci., Univ. of Hyogo
Grouping behavior is one of the survival strategies in many animal species. Each species displays distinct traits of grouping behavior. For example, some animal species actively form groups, others do not form any groups. At the individual level, decision-making, such as approaching or avoiding other individuals, is considered to determine the differences of grouping behavior between species. However, it remained unclear what neural mechanisms control the characteristics of decision-making responsible for group formation. This study aims to clarify this mechanism using Drosophila melanogaster and other Drosophila species. D. melanogaster does not show a distinct grouping behavior. We observed the grouping behavior of 20 flies in 9 Drosophila species and found that several of them form dense groups, unlike D. melanogaster This finding enables interspecific comparison of grouping behavior from a neuroethological perspective. Furthermore, we found that activation of specific neurons in D. melanogaster causes artificial grouping behavior. This result suggests that a small subset of brain neurons controls the characteristics of grouping behavior.
P1-43 Starvation enhances cold tolerance of C. elegans and its artificial evolutionary analysisSeiya Kamino1, 2, Haruka Motomura1, 2, Atsushi Kuhara1, 2, Akane Ohta1, 2
1Graduate school of Natural Science, Konan University, 2Institute for integrative Neurobiology, Konan University, Japan
Adaptation of animals to changing temperatures is an essential ability to survive and proliferate. C. elegans has a cultivation temperature-dependent cold tolerance: wild-type animals grown at 15℃ can survive at 2℃, while those grown at 25℃ die. In this study, we found that starvation enhances cold tolerance of C. elegans, and are investigating its molecular mechanisms by using various mutants such as mutants impairing monoamine signaling involved in starvation and food recognition. As another topic, we are utilizing artificially evolved C. elegans against temperature stimuli to reveal how animals have adapted and evolved themselves against temperature changes to maintain their diversity as species, at the genome level. C. elegans is hermaphrodite, has a short generation period, and can be frozen storage. Based on these advantages, we have been maintained and freeze-preserved up to ～1000 generations of 23℃-cultivated wild-type and up to 550 generations of 15℃-cultivated wild-type. We found that about 500 generation-animal maintained at 23℃ showed abnormal cold tolerance. We are attempting to decode the genomes of frozen-animals by using deep DNA sequencer.
P1-44 The Brain Barrier System as a “Brain Endocrine System” : A Novel Perspective on Active Behavioral ControlHikari Kaga1, Moe Yamashita1, 2 Ryoma Watanabe2 Akiyoshi Hirayama4, 5 Akio Kanai4, 5 Tomoyoshi Soga4, 5 Teruhiro Okuyama6 Takafumi Katsumura2, 7 Kataaki Okubo8 Yasuo Uchida9 Satoshi Ansai1, 10 Hideaki Takeuchi1, 2
1Grad. Sch. Life Sci., Tohoku Univ. 2Grad. Sch. Nat.Sci., Okayama Univ. 3Dep. Sci., Tohoku Univ. 4IAB, Keio Univ 5Grad. Sch. Media&Governance, Keio Univ 6IQB, The Univ. of Tokyo 7Dept. Anatomy, Kitasato Univ. Sch. Med. 8Grad. Sch. of Agric. and Life Sci., The Univ. of Tokyo 9Grad. Sch. Biomed. Health Sci., Hiroshima Univ 10Grad. Sch. Agri. Kyoto Univ.
The brain barrier system, at the brain-bloodstream interface, regulates substance exchange and maintains cerebral homeostasis. Traditionally seen as a passive filter, emerging research suggests it plays a dynamic role. This study proposes that the brain barrier system acts as an active“brain endocrine system”influencing behavior. Using medaka (Oryzias latipes), initial investigations revealed that social rank influenced hpdb gene expression, involved in tyrosine-phenylalanine metabolism. Mutation of the hpdb gene resulted in elevated brain dopamine levels, leading to increased aggression and susceptibility to attacks. This suggests social stress may modulate tyrosine metabolism in the brain barrier system, affecting behavior. To verify if this system is conserved among mammals, we used mice and conducted RNA-seq analysis on the choroid plexus under social defeat stress. The stress dramatically altered gene expression profiles, including amino acid transporters and hormones, suggesting social stress biases cerebrospinal fluid composition. Our study supports that the brain barrier system functions as an active“brain endocrine system,”influencing brain function and behavior.
P1-45 The Effect of Pheromone Loss on Ant TrailYuto Fukuta, Tomoko Sakiyama
Dept. Info. Sys. Sci. Soka Univ.
The effects of pheromone removal on ant populations were analyzed using the garden ants. Two bridges connecting the feeding area to the nest are prepared as devices, and a 10 cm piece of paper is placed in the center of each bridge. The device is designed to allow ants to move back and forth over the bridge, and when the paper is removed, the pheromone in the area where the paper was placed temporarily disappears. Two different experiments were conducted. In the first experiment, the ants were directed to the feeding site for a certain period of time, and then the paper on the bridge where the ant population was high was removed to temporarily eliminate the pheromone. In the second type of experiment, neither of the two bridges was used to remove the pheromone, and the ants were allowed to head to the feeding area with the pheromone always present. The results of two different experiments showed that as a group they continually select one bridge. After the removal of the pheromone, the ant trails are restored, suggesting that the removal itself has no negative effect on the subsequent use of the ant trails.
P1-46 The neural mechanism of flower recognition by color vision of Drosophila elegansMunehiro Katsura1, Kohei Fujii1, Kohei Kawamura1, Kentaro Arikawa2, Atsuko Matsushita2, Michiyo Kinoshita2, Yuki Ishikawa1
1Dept. Biol. Sci., Grad. Sch. Sci., Nagoya University 2RCIES, Sokendai
Various insects visit flowers; nevertheless, the neural mechanism for their flower recognition remains largely unknown. To elucidate this question, we focused on Drosophila elegans, which visits flowers for breeding and feeding in the wild. To verify which modalities flies use to recognize flowers, we presented an artificial flower to flies. Flies innately visited the artificial flower, indicating that the flies can recognize flowers by vision. To identify the visual key stimuli for the recognition, various colored papers were presented to the flies. Flies selectively landed on blue and white papers, which are similar to those of flowers they visit in the wild, suggesting that the flies use color information to recognize flowers. To verify which photoreceptor cells contribute to flower recognition, we focused on sevenless (sev) gene, which is required for the development of UV and blue receptor cells. We created sev mutant flies by using CRISPR/Cas9 and observed the landing behavior to blue papers. The mutant flies rarely landed on blue papers, suggesting that UV and/or blue receptor cells contribute to flower recognition.
P1-47 The neural mechanism that regulates the ejaculation during copulation in Drosophila male*Hayato M Yamanouchi, Ryoya Tanaka, Azusa Kamikouchi
Dept. Biol. Sci., Grad. Sch. Sci., Osaka University
In animals with internal fertilization, the male ejaculates during copulation to transport sperm to the female. In D. melanogaster, a previous study identified the ejaculation-promoting neurons that co-express the fruitless and corazonin genes in the ventral nerve cord (VNC) of males. However, the neural inputs that control the activity of this subset of neurons to induce ejaculation remain unidentified. Here, we aim to clarify the neural circuit upstream of the ejaculation-promoting neurons. Using retro-Tango, a retrograde tracing tool of neurons, we found the possible candidate neurons upstream of the ejaculation-promoting neurons. Interestingly, these candidate neurons project their neurites both to the bristles of the male genital sensilla and the ejaculation-promoting neurons in the VNC, implying that sensory information from the male genitalia is directly involved in the regulation of the ejaculation-promoting neurons. To identify the type of neurotransmitter input to the ejaculation-promoting neurons, we also attempted to identify the genes encoding neurotransmitter receptors that function in the ejaculation-promoting neurons by RNA interference screening.
P1-48 The praying mantis changes the position of prey-gripping flexibly based on prey’s features.Shunsuke Yoshimitsu¹, Yoshifumi Yamawaki²
¹Dept. Biol. Sci., Grad. Sch. System Life Sci., Kyushu University ²Dept. Biol. Sci., Grad. Sch. Sci., Kyushu University
Feedback control is an important mechanism for animals to behave precisely. The mantis often changes the grip position held with its forelegs after capturing a prey, for more stable holding. This behavior presumably requires sensory feedback control, but there is little study on it. We refer to this behavior as‘re-gripping’and aimed to reveal its neural mechanism. In this study, to clarify its characteristics and conditions for eliciting it, we video-recorded and analyzed the foreleg movements after capturing a cricket or an artificial prey with a high-speed camera. The results showed that one of mantis’ tibia was moved laterally during re-gripping. The body size of the cricket significantly affected the occurrence rate of re-gripping, suggesting that it occurs more often when prey is larger. Against artificial prey, the mantis showed re-gripping behaviors similar to those against a cricket. From these results, we hypothesized that the mantis detects the prey’s center of gravity to determine grip position, or it only uses visual guidance to decide the position of gripping. We will report the results of experiments testing these hypotheses.
P1-49 The role of retinal regions in visual guiding during sequential pecking of pigeons: an eyecap occlusion experimentKenta Wada, Ei-Ichi Izawa
Dept. of Psy., Keio University
Reaching-to-grasping is a fundamental behaviour for foraging in various animals. Unlike primates, the head/neck reaching of birds produces unstable visual inputs because their eyes (sensory organs) and bills (effectors) are located in the head. Ground-feeding birds such as pigeons stop head movement to the target before reaching, called fixation, which is assumed to plan the trajectory of reaching the target. Birds have two retinal regions with different depths of focus: the area dorsalis and the fovea centralis can receive hi-res images at a near and far distance, respectively. Previous studies suggested that pigeons fixated initially on the farther target and subsequently on the nearer ones in sequential pecking. However, the use of the two retinal regions has yet to be experimentally tested. This study aimed to examine the effects of an eyecap to occlude either central or dorsal retinal region on pecking. Visual distances and fixation durations were compared between the central and dorsal occluded conditions. We found that pigeons with occlusion of the area dorsalis can peck the targets, suggesting the area dorsalis is not necessarily used for fixation.
P1-50 Theoretical prediction for photoreaction pathways of a putative avian magnetoreceptor cryptochrome4*Hiroaki Otsuka1, Ryosuke Miyake1, Keiko Okano1, Yasushi Imamoto2, Toshiyuki Okano1
1Dept. Elect. Eng. Biosci., Grad. Sch. Adv. Sci. Eng., Waseda University 2Dept. Biophys., Grad. Sch. Sci., Kyoto University
P1-51 Transcriptome analysis of Protophormia terraenovae in search of photoperiod-age dependent genes involved in synaptic transmission*Jacqueline Png1, Jili Xi2, Sakiko Shiga1
1Dept. Biol. Sci., Grad. Sch. Sci., Osaka Univ., 2Int. College, Osaka Univ
Organisms use day length as a cue to detect seasonal changes to adapt accordingly. Protophormia terraenovae adults respond to short day conditions of 12L12D 20℃ to undergo reproductive diapause. This photoperiodic response is induced within 7 days, indicating day length measurement occurs in earlier adult stages. Thus, both photoperiod (short or long days) and age (3 or 7 days after eclosion) are thought to be crucial when understanding how the photoperiodic clock reads photoperiodic information. While neural circuitries crucial for inducing photoperiodic responses have been studied in this organism, the neurotransmitters involved are still a mystery. Hence, to detect transmitter candidates, we used RNA-Seq data to examine genes involved in synaptic transmission, of which expression levels are photoperiod and age dependent. Weighted Gene Correlation Network Analysis picked up 7 photoperiod dependent modules and two photoperiod and age dependent ones. BLAST analysis of the latter modules detected excitatory glutamate pathways upregulation under day 3 and short day conditions, suggesting the pathway’s involvement in early stage processing of photoperiodic response in P. terraenovae.
P1-52 Transfection of fluorescence-labeled plasmids into primary cultured cells of the pond snail, Lymnaea*Kengo Namiki1, Miku Kato1, Naoki Hatashita1, Emiko Hayama2, Etsuro Ito1
1Dept. Biol. Waseda Univ. 2Ped.Cardiol. TWMU
The pond snail Lymnaea stagnalis has long been used to study learning and memory. Lymnaea can be used to study molecular influences on behavior because of the simple control mechanism for the structure of the hierarchy that runs from the molecular to the behavioral level. Therefore, it is important to apply state-of-art genetic manipulation to Lymnaea. Then, we performed plasmid transfection into primary cultured cells of Lymnaea by the lipofection and magnetofection methods using fluorescence-labeled plasmids and checked the localization of plasmids. Many vesicles containing the plasmids were seen on the cell surface, especially in magnetofection, the vesicles were observed on the upper surface of adherent cells. In addition, a few cells showed fluorescence at positions considered to be intracellular and nuclear. This suggests that it is possible to introduce some plasmid by either lipofection or magnetofection, and it is necessary to adjust the conditions for reagent amounts to allow introduction with higher effectiveness. We will consider a method using the endogenous promoter of Lymnaea and promoters that have been shown to be effective in other molluscs.
P1-53 Two types of melanopsins play differential roles in regulating background adaptation in a light-intensity-dependent manner*Kazuhiko Takemae and Daisuke Kojima.
Dept. Biol. Sci., Sch. Sci, Univ. Tokyo
P1-54 UV-light induced expression of Cryptochrome6 in the isolated zebrafish eye*Takumi Taira, Minami Suehiro, Keiko Okano, Toshiyuki Okano
Dept. Elect. Eng. Biosci., Grad. Sch. Adv. Sci. Eng., Waseda Univ.
P1-55 Wavy synchronization in leg movements of train millipedes revealed by automatic tracking and mathematical modeling*Momiji Yoshikawa, Ikkyu Aihara
College Eng. Syst., Sch. Sci. Eng., Univ. Tsukuba
Synchronization can be observed in various biological systems such as in-phase synchronization of flashing fireflies and anti-phase synchronization of calling frogs. From preliminary experiments, we observed that train millipedes (Parafontaria laminata armigera) cooperatively controls multiple legs and shows nearly synchronous pattern. This study aims to examine the synchronous walking pattern in train millipedes both experimentally and mathematically. First, we recorded and analyzed the walking pattern of actual millipedes. The millipedes were captured in Mt. Hachibuse, Nagano Prefecture, and their movements were recorded from the side using a video camera. Multiple body parts (each leg tip, head, and tail) were tracked using DeepLabCut. Consequently, we succeeded in detecting the synchronous walking pattern. Next, we proposed a mathematical model to reproduce the empirical data. Specifically, we introduced a phase-shift parameter in the interaction term of the Kuramoto model and estimated the unknown parameter by using the empirical data. Consequently, the simulation of the estimated model successfully reproduces the synchronous walking pattern in train millipedes.
P2-1 A falling attribute in the first instar nymph of the cicada Cryptotympana facialis*Masaki Sakai, Kiyoshi Nakahori, Michinobu Mino
Grad. Sch. Nat. Sci. Tech. Okayama Univ.
Cicada nymphs (2 mm long) shortly after hatching keep clinging to a twig of the zelkova tree. Within 30-60 min, they fall abruptly one after another. Then they start walking actively on the flat substrate in the light direction. If rich soil is available, they crawl into it through a chink. In the field experiments nymphs are released near holes (2 cm wide, 5-10 cm deep) under a zelkova tree that had been made by 5th instar nymphs for evacuation. Nymphs quickly fall into the hole when they come across the edge of a hole. These two types of the falling are adaptive for nymph’s survival. The first falling is indispensable because dying twigs (< 1 cm in diameter) used for egg-laying are localized in the distal portion of the tree branch. It is so remote to walk along the tree down to the ground. The second falling is an easy way to reach good environments for their living. Microscopic observations indicated that one of the causes of the nymph’s falling was due to underdeveloped tarsal claws of the 6 legs that were too small (about 80μ long) to get thin edges on the rough surface of the twig or wall for moving. Such a functionally poor attribute paradoxically works in their favor.
P2-2 Analysis of the distribution of dendrites of Kenyon cell subtypes in honey bee mushroom bodiesMakoto Fujikawa, Takeo Kubo, Hiroki Kohno
Dept. Biol. Sci., Grad. Sch. Sci., The Univ. Tokyo
The European honey bee (Apis mellifera L.) is a eusocial insect, and its mushroom bodies (MBs), a higher order center of the insect brain, are composed of 3 (large- middle-, and small-type) Kenyon cell (KC) subtypes with distinct somata location and gene expression profiles. The MB calyces where KCs extend their dendrites comprise 3 compartments termed lips, collars, and basal rings, each of which receives sensory inputs from the olfactory center (antennal lobes), the visual center (optic lobes), and both, respectively. However, it remained unclear to which calycal compartment each KC subtype extends its dendrites. Here, we performed co-staining of MBs by both neural tracer injection and fluorescence in situ hybridization of a KC subtype marker gene. Our results suggested that large-type KCs extend their dendrites into either lips or collars and receive either olfactory or visual sensory input, while middle- and small-type KCs extend their dendrites into basal rings and receive both olfactory and visual sensory inputs. Based on these findings, the possible roles of each KC subtype in the regulation of honey bee behaviors are discussed.
P2-3 Neural processing in the anterior optic tubercle of a swallowtail butterflyMichiyo Kinoshita
RCIES, SOKENDAI
The anterior optic tubercle (AOTU) is a pair of neuropils located at the anterior dorsolateral area and next to the lobe of the mushroom body in the central brain of lepidopteran insects. The AOTU consists of four sub-regions: upper unit, lower unit, nodular unit, and strap. The lower unit is a relay region containing polarized-light sensitive neurons for sky compass navigation in some insects. In contrast, the function of the upper unit (AOTU-uu) is still unexplored well. I first investigated the neural pathways through the AOTU-uu by dye injection. In the optic lobe, I found many neurons stained in the fourth layer of the medulla, as well as the second and third layers of the lobula. I also found connections between the AOTU-uu and many areas of the protocerebrum, including the lateral accessory lobe and the contralateral AOTU-uu. Because the AOTU-uu possibly receives spectral opponent information from the medulla, I measured the spectral responses of AOTU neurons. As expected, I found neurons showing spectral opponency and sensitivity to broad wavelength regions, suggesting that the AOTU-uu integrates visual modalities, such as color and brightness.
P2-4 Behavioral and physiological responses of Orius strigicollis to different wavelength and intensity of light*Ryota Numazawa¹, Hirono Ohashi², Naoya Fujimoto³, Yoichi Seki³, Shusuke Shigaki⁴, Yasuharu Takaku², Takeshi Sakurai²
1Grad. Sch. Agric., Tokyo Univ. Agric. 2Fac. Agric., Tokyo Univ. Agric. 3School of Life Sci., Tokyo Univ. Pharm. Life Sci. 4Prin. Info. Res. Div., NII
P2-5 Color vision of the hoverfly Episyrphus balteatus revealed by a newly developed associative visual learning assay*Yoichi Seki1, Tatsuki Hirakoso1, Junji Yamauchi1, Michiyo Kinoshita2
1Sch. Life Sci., Tokyo Univ. Pharm. Life Sci. 2Dept. Evol. Stud. Biosyst., Sch. Adv. Sci., Grad. Univ. Adv. Stud., SOKENDAI
Color is an important cue for insect pollinators to detect flowers. Hoverflies have been known as major pollinators after bees, however their sensory perception for flower detection remains elusive due to the scarcity of behavioral studies. We have developed an associative learning assay in the hoverfly E. balteatus, where learned discrimination abilities of the hoverfly can be evaluated by associating sensory cues of an artificial flower with a sucrose reward. First, using the two-choice test, we demonstrated that hoverflies could rapidly learn to discriminate blue and yellow artificial flowers by visual cues, and the memory could be overwritten by switching the trained color. We further conducted the multiple-choice test for four colors including blue, yellow, green and red, and von Frisch’s gray card experiments for each of these colors. We found that blue, yellow and red was reliably discriminated from other colors and a variety of shades of gray, while green was less discriminable. These results suggest that color vision of the hoverfly might be adapted for discriminating variety of flower colors rather than the color of foliage background.
P2-6 Development of an optical encoder-based angled running wheel system for mouse locomotion analysis*Naohisa Nagaya1, Naoki Ide2, Yuta Nakamura1, Yudai Yamamoto2, Kan Nakatani2, Takuya Oka2, Keiko Kato2
1Fac. Info. Sci. & Eng., Kyoto Sangyo Univ. 2Fac. Life Sci., Kyoto Sangyo Univ.
P2-7 Directional swimming of Chlamydomonas cells showing thermotaxis*Taro Kaneko, Kenjiro Yoshimura
Sys. Engineer. Sci. Course, Grad. Sch. Sci. Technol., Shibaura Inst. Technol.
P2-8 Does the doublesex gene regulate neural/behavioral sexual dimorphism in crickets?*Takayuki Watanabe
RCIES, SOKENDAI
Courtship and male-male aggression are widely observed in animals, including insects. Since these behaviors involve sex-specific behavioral patterns, it is believed that the neural circuits in the brain that regulate these behaviors must also be sexually dimorphic. The sexually dimorphic circuits in the Drosophila brain are produced by two sex-determining transcription factors, fruitless and doublesex, which undergo sex-specific splicing regulation by the splicing factor transformer. However, it remains obscure whether the sex-determination mechanism found in Drosophila is widely conserved throughout approximately 500 million years of insect evolution. I have been studying the evolution and diversity of molecular and cellular mechanisms of the neuronal sex-determination system in insects, with a particular focus on the two-spotted cricket Gryllus bimaculatus, a model hemimetabolous insect that diverged from the holometabolous insect lineage approximately 400 million years ago. In this presentation, I will present my recent my recent findings on the homologues of the doublesex gene, a member of the conserved metazoan sex-determination factor family, in cricket.
P2-9 Effects of mating restriction on lifespan and capability of memory formationYukihisa Matsumoto
Liberal Arts and Sciences Division, Institute of Education, Tokyo Medical and Dental University
I have reported that crickets exhibit age-related memory impairment with a substantial decline in long-term memory (LTM) formation after the average lifespan (15 days from adult molting). On the other hand, it has been reported that in various animals, certain rearing conditions (e.g., low temperature, food restrictions, mating restrictions, etc.) extend their lifespan. However, few studies have examined the memory formation capability of the animals that experienced the lifespan-extending treatment. In this study, I examined the lifespan and the ability of LTM formation in mating-limited crickets reared in males-only or females-only conditions after the final molt. Compared to the control group in which males and females were reared together, the results showed that the lifespan of the male-only and female-only rearing groups were both extended by about 1.5 times, but the LTM formation ability showed a decline earlier (<10 days). Furthermore, when the male and the female crickets with LTM impairment were paired for one hour, their LTM formation ability was restored.
P2-10 Fibrinopeptide A serves as a negative regulator of blood-feeding in the yellow fever mosquito Aedes aegypti*Chisako Sakuma1, Fumiaki Obata1, 2, Hirotaka Kanuka3, 4
1RIKEN BDR, 2Grad. Sch. Biostudies, Kyoto Univ., 3Dept. Trop. Med., Jikei Univ. Sch. Med., 4Ctr. Med. Entomol., The Jikei Univ. Sch. Med.
Female mosquitoes engage in blood-feeding from their hosts to facilitate egg production, but they cease feeding and leave the host once a sufficient blood meal has been acquired. Adenosine triphosphate (ATP) within the host’s blood is widely recognized as a potent phagostimulant for various blood-feeding arthropods, including mosquitoes. However, the negative regulators of blood-feeding remain unidentified. In this study, we observed that serum derived from animal blood exhibits inhibitory properties on ATP-feeding in Aedes aegypti. We identified fibrinopeptide A (FPA) as the inhibitory factor within the serum. FPA is a 16-amino acid peptide that is cleaved from fibrinogen during blood coagulation. Administration of batroxobin to mouse blood, a snake venom with thrombin-like properties that specifically cleaves FPA from fibrinogen, resulted in the inhibition of blood feeding. These findings suggest that the blood-feeding arrest in female mosquitoes is triggered by the detection of FPA, which increases as blood coagulation progresses in the mosquito’s midgut. Mosquitoes may employ FPA as a means to gauge the volume of blood ingested and the duration of blood-feeding.
P2-11 Fluorescent labeling of neurons involved in olfactory memory evocation using TRAP miceYoshihiro Murata, Wakana Okami, Maho Asano, Mutsuo Taniguchi, Masahiro Yamaguchi
Dept. Physiol., Kochi Med. Sch.
P2-12 Functional characterization of novel intracellularly-localizing viral rhodopsins*Takashi Nagata1, Shunki Takaramoto1, Andrey Rozenberg2, Oded Béjà2, Keiichi Inoue1
1ISSP, The Univ. Tokyo, 2Fac. Biol., Israel Inst. Technol.
P2-13 Identification of candidate olfactory receptor genes in the Japanese Beetle, Popillia japonica, using de novo antennal RNA-seq analysisShintaro Imai1, Keisuke Tanaka3, Kazuma Kishimura1, Hirono Ohashi2, Yasuharu Takaku2, Takeshi Sakurai2
1Grad. Sch. Agric., 2Fac. Agric., Tokyo Univ. Agric. 3Tokyo Univ. Info. Sci.
P2-14 Identification of candidate olfactory receptor genes in the minute pirate bug O. strigicollis by antennal transcriptome analysisNao Iida1, Keisuke Tanaka2, Hirono Ohashi1, Yasuharu Takaku1, Takeshi Sakurai1
1Dept. Agric. Innoy, Sustain. Soc., Tokyo Univ. Agric. 2Dept. info., Tokyo univ. info. Sci.
P2-15 Imaging vestibular and auditory mechanisms in otolith organs of larval zebrafish*Masashi Tanimoto, Shin-ichi Higashijima
Div. Behav. Neurobiol., NIBB
Otolith organs in the fish ear detect head tilt, linear acceleration, and sound. Larval zebrafish have two otolith organs, the utricle and saccule. Previous in vivo Ca2+ imaging of hair cells (HCs) in the larval zebrafish utricle showed that vibration stimulus is mainly transduced by HCs in the specialized region called striola, while static tilt is preferentially received by the extrastriolar HCs (Tanimoto et al., Nat. Commun., 2022). Mechanisms underlying this spatially segregated response selectivity remain unclear. We imaged the utricular otolith and hair bundle movements during static tilt. The otolith displaced due to the gravity and exhibited a compound motion, comprising both pivoting and translational components. The pivoting motion induced larger hair bundle displacement in extrastriolar HCs compared to striolar HCs, correlating with their differential responses to static tilt. We also imaged HC activity during sinusoidal linear acceleration at various frequencies. In the utricle and saccule, HCs showed a topographic tuning pattern to the stimulation axis and frequency. These results reveal spatially segregated response selectivity in larval otolith organs.
P2-16 Investigation of phototactic behaviors in brine shrimp nauplius larvae*Seiji Wada1, Sakiko Sakata1, Mitsumasa Koyanagi2, Akihisa Terakita2, Hiromi Hirata1
1Col. Sci. Eng., Aoyama Gakuin Univ. 2Grad. Sch. Sci., Osaka Met. Univ.
Most animals possess photosensory systems that utilize photosensitive opsin molecules to generate light-dependent behaviors. One example of this is orientation behavior based on an animal’s photosensitivity. For instance, brine shrimp exhibit phototactic behavior. In the adult stage, they turn their ventral side toward the light, which is a reflection behavior that relies on the photoreception of their compound eyes. In the nauplius larval stage, the larvae exhibit simple phototactic behavior, moving toward a light source. Recently, we observed that the larvae switch between positive and negative phototactic behaviors in response to constant light. Brine shrimp nauplius larvae possess a single median eye, known as a naupliar eye, located in the center of their head, but they do not have compound eyes. Although it is interesting how this behavior switching involves the photosensory system in the naupliar eye, the mechanisms such as opsin-based descriptions remain unknown. In this study, we attempted to quantify positive and negative phototactic behaviors and aim to discuss the behavior switch in response to light in brine shrimp.
P2-17 Ionotropic receptor co-receptors for odor receptions in the American cockroachKosuke Tateishi1, 2, Takayuki Watanabe3, Hidehiro Watanabe2
1Sch. Bio. Environ. Sci. Kwansei Gakuin Univ. 2Dept. Earth Syst. Sci., Fukuoka Univ. 3Res. Cent, Integr. Evol. Sci., SOKENDAI-Hayama.
Ionotropic Receptors (IRs) are part of the iGluR-like protein family, and they have various functions in animals within the Protostomia lineage. In a model insect, Drosophila melanogaster, IRs are involved in detecting tastes, odorants and other environmental stimuli such as humidity and cooling temperatures. Olfactory IRs form heteromeric complexes consisting of a ligand-specific tuning protein and a co-receptor (IRco). The odorant selectivity of olfactory sensory neurons via IRs is categorized by three IRcos: IR8a is essential for detecting acids, while IR25a and IR76b play important roles in detecting amines. However, these IRco functions in other insects remain largely unclear. In this study, we identified IRco orthologs expressing in the antennae of the cockroach Periplaneta americana, and termed PameIR8a, PameIR25a, and PameIR76b. By combination of RNAi for each IRco ortholog and electrophysiological experiments, we investigated their functions for odor receptions. In this study, we demonstrated that these IRco functions are highly conserved between a holometabolous fly and a hemimetabolous cockroach. These findings provide new insights into evolution of insect olfaction.
P2-18 Light in rearing is critical to development of body color change ability in larval zebrafishJiarun Zhang, Kazuhiko Takemae, Daisuke Kojima
Department of Biological Sciences, School of Science, The University of Tokyo
P2-19 Localization of Neuropeptides at Different Developmental Stages and Functional Analysis of the PRXa Peptide Family in the Cnidarian NematostellaRyotaro Nakamura, Chihiro Kawano, Lada Dolezalova, Hiroshi Watanabe
Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology
The neuroendocrine system in bilaterians releases neurotransmitters such as neuropeptides in response to environmental stimuli, playing a crucial role in maintaining and regulating the internal environment. Cnidarians, the closest sister group to bilaterians, also exhibit numerous neuropeptides, but functional analysis of these molecules is still in its early stages.
In this study, we investigate the early evolutionary processes of the neuroendocrine system by examining the localization of neuropeptides at different developmental stages in the model cnidarian Nematostella. Our research focuses particularly on the PRXa peptide family, aiming to provide insights into their functional roles during development. Our findings reveal significant patterns of neuropeptide distribution, suggesting potential evolutionary links to bilaterian neuroendocrine systems.
P2-20 Manipulation of aggressive behavior in the cricket using a small robotTatsuya Ueda*1 Yasuhiro Sugimoto2, Hitoshi Aonuma1
1Grad. Sch. Sci., Kobe University 2Grad. Sch. Eng., Osaka University
Virtually all animals show aggressive interaction between conspecific individuals for resources such as food, territory, and mating partners. Crickets have been used to investigate neuronal mechanisms underlying aggressive behavior. They start antennal fencing when they encounter each other. Then their aggressiveness increases to show tactile contact if one of them retreats from the fight. Once the fight is settled, the dominant-subordinate relationship is established. The subordinate rarely shows aggressiveness when it encounters other cricket but shows avoidance behavior. The result of the fight in cricket is by chance, which makes it difficult to predict which one will be the winner. We here propose a small robot system that manipulates the results of the fight. One of the advantages of the use of the small robot must be that we can manipulate the aggressiveness of the crickets, which makes it easier to compare the physiological events while fighting for the winner or loser.
P2-21 Neuromolecular Mechanisms Responsible for Flexibility in Drosophila Motor ControlYoshinori Suzuki1, Kazuhiko Kume2, Minoru Saitoe1
1Grad. Sch. Pharma. Sci., Nagoya City University 2Tokyo Met. Inst. Med. Sci.
Central pattern generators (CPGs) are thought to generate typical gait patterns in animals. However, the real-world flexible motor abilities of animals cannot be solely explained by these patterns. If behaviors were solely defined by CPGs, animals would be unable to adapt to new situations and environments. Thus, the nervous system must be capable of generating specific motor patterns and adjusting them to produce appropriate movements. Flexible body control requires integrating efferent motor commands and afferent sensory feedback, such as proprioceptive sensations. The exact integration process and its role in body control remain unclear. This study shows that the NMDA receptor in the ventral nerve cord is crucial for adaptive movements in Drosophila. We observed that NMDA receptor mutants exhibit normal gait but have difficulty with tasks requiring complex leg coordination. This finding suggests that NMDA receptors are essential not for basic motor pattern generation like CPGs, but for dynamic systems that generate adjusted motor controls. We would like to discusse the integration of motor commands and sensory feedback via NMDA receptors.
P2-22 PTSD-related genes mediate synaptic drive incoordination that triggers sleep disturbance*Masashi Tabuchi, Makenzie Anne Hopkins, Dieu Linh Nguyen, Matthew Girgenti, Alicia Che
1Dept. Neurosci., Case Western Reserve University School of Med 2Dept. Psychiatry., Yale School of Med
PTSD can disrupt circadian rhythms due to hyperarousal and heightened stress responses, resulting in altered sleep patterns and difficulty maintaining consistent sleep-wake cycles. Recent data has shown that individuals with ELFN1 gene mutations may be more susceptible to developing PTSD due to the gene’s effects on synaptic function and circadian regulation. However, we still do not know the molecular, cellular, and neurophysiological basis of how PTSD can be related to sleep disturbances. In the present study, we utilize RNAi knockdown of three fly homologs of ELFN1 gene, fili, trn, and kek3, to identify their contributing factors in functional biophysical parameters of the circadian network in Drosophila. We find that RNAi-induced modulation of the membrane potential and synaptic properties in the circadian networks, with changes in the temporal pattern of synaptic coordination, induces sleep disturbances in Drosophila. Together, these data reveal the biophysical identity of the PTSD-related genes, and how circadian network properties to influence sleep profiles can be evolutionally conserved.
P2-23 Peripheral sensory mechanisms underlying discrimination of salty water and brain locus for salt appetite in mudskipperRisa Matsuda1, 2, Takao Mukuda2, Kazuya Fukuda3, Sawako Hamasaki2, Toshiyuki Kaidoh2
1Div. Neurosci., Grad. Sch. Medical Sci., Tottori Univ. 2Dept. Anat., Fac. Med., Tottori Univ. 3Lab. Reproductive Physiol. Aquat. Organisms, Sch. Marine Biosci., Kitasato Univ.
Sensory mechanisms to discriminate salty or fresh water (FW) in the habitat and brain locus perceiving salt appetite were examined using an amphibious and euryhaline goby, mudskipper. Applying the free choice test where three small pools filled with different salinity water (35 psu, seawater; 10, brackish water, BW; 0, FW) were set in the floor of the experimental arena, mudskipper was released on the floor to select preferable water. Time staying in BW was markedly prolonged than in other waters, indicating that mudskippers enable to discriminate salty water and prefer BW to other water. Further, Na＋ in the water was found to be the essential for the choice in the associated experiment. To examine the peripheral sensing for Na＋ in habitat water, the free choice test was performed using the mudskippers which narial openings or oral mucosa was covered with Vaseline to prevent contact water. This treatment extended the time staying in FW, suggesting that Na＋ is perceived through the sense molecules expressing on the nasal and/or oral mucosa. In the CNS, a candidate site perceptive for salt appetite was found in the preoptic area in the forebrain histologically.
P2-24 Real-time volumetric neural recoding of the whole brain in naturally behaving nematode worms by high-speed light-sheet microscopyYusuke Tomina1, Yu Toyoshima2, Kazuki Mukumoto3, Hikaru Shishido3, Chentao Wen4, Manami Kanamori2, Koyo Kuze2, Yuko Murakami5, Suzu Oe5, Takeshi Ishihara6, Shuichi Onami4, Yuichi Iino2, Hideharu Mikami1
1Res. Inst. Electro. Sci., Hokkaido Univ., 2Dept. Biol. Sci., Sch. Sci., Univ. Tokyo, 3Grad. Sch. Info. Sci. Tech., Hokkaido Univ., 4RIKEN BDR, 5Grad. Sch. Sys. Life Sci., Kyushu Univ, 6Fac. Sci., Kyushu Univ.
Understanding the neural mechanisms underlying animal behavior is a fundamental goal in neuroscience. To fully understand these mechanisms, it is crucial to record individual neuronal activities at the whole-brain level in real time during free behavior. Caenorhabditis elegans, a nematode whose brain has ～190 neurons, serves as an ideal model organism for such recordings. However, conventional optical microscopes face a challenge of large motion artifact due to their slow imaging speed of up to ～10 Hz, making it difficult to accurately detect and track individual neurons during natural locomotion. Here, we present a high-speed volumetric calcium imaging system with single-cell resolution capable of whole-brain recordings of neuronal activities from the worm during natural behavior. With a newly developed fast image acquisition mechanism, our microscope overcomes this challenge by serving volumetric images at a high speed over 50 Hz.
P2-25 Scaling Laws in Behavioral Initiation in Crayfish and Mantis ShrimpKatsushi Kagaya
Faculty of Engineering, Kitami Institute of Technology
P2-26 Screening for a pheromone degrading enzyme in the male antennae of the silkmoth, Bombyx mori*Ritsuki Wakabayashi1, Yukiko Uchikoshi2, Hirono Ohashi2, Yasuharu Takaku2, Takeshi Fujii3, Takeshi Sakurai2
1Grad. Sch. Agric., Tokyo Univ. Agric., 2Fac. Agric., Tokyo Univ. Agric., 3Fac. Agric., Setsunan Univ.
P2-27 Screening for thermosensitive GPCR involved in heat tolerance in nematode C. elegansShiori Mototake1, Yuki Sato1, 2, Kohei Ohnishi1-3, Tohru Miura1-3, Akane Ohta1-3, Atsushi Kuhara1-4
1Dept. Biol., Facul. Sci & Engineer. Konan Univ., 2Dept. Biol. Grad. Sch. Sci. Konan Univ., 3Inst. of Integral NeuroBiol. Konan Univ., 4PRIME AMED
We have been studying thermosensory mechanisms of cold tolerance in C. elegans, in which GPCR acts as thermo-receptor (Ohnishi et al., Nat. commun., 2024; Ohta et al., Nat. commun., 2014). Here we tried to analyze whether thermosensory molecules are common between cold tolerance and“heat tolerance”in C. elegans. 15℃ -grown wild-type cannot survive at 31℃ for 24h, but can survive at 31℃ for 24h after grown at 25℃. Mutation in the cGMP-gated channel TAX-4 required for cold tolerance caused an abnormally increased heat tolerance, which was restored by expressing tax-4wt gene in both ASJ and ASI. Since TAX-4 is activated by signals from GPCR, we set out to find thermosensitive GPCR on heat tolerance in ASJ or ASI. Via RNAi screen for about 1000 GPCRs, 86 of the knocked-down lines showed abnormal cold tolerance (Ohnishi et al., Nat commun, 2024). Since 13 of these GPCR genes were expressed in ASJ thermosensory neurons. Multiple mutants of several GPCRs, including str gene specifically expressing in ASJ, were generated. We are trying to measure heat tolerance of the multiple GPCRs mutant to identify thermo-receptor GPCRs working in ASJ thermosensory neurons.
P2-28 Single-trial representation of behavioral task related information by decomposed ensemble activity in rat frontal cortico-striatal circuitTakashi Handa
Dept. Neurobiol., Grad. Sch. Biomed. and Health Sci., Hiroshima University
The frontal cortex-basal ganglia network in the cerebrum plays a pivotal role in adaptive goal-directed behaviors such as decision-making based on outcomes of past action. However, little is known about how the neural ensembles in rodent frontal cortex-basal-ganglia circuit encode task-related information at single-trial level during adaptive behavior. We analyzed neuronal ensemble activity obtained in the secondary motor cortex (M2) and dorsal striatum (DS) in rats performing an outcome-based choice task. By adopting tensor component analysis (TCA), a single-trial-based unsupervised dimensionality reduction approach, for ensembles of M2 and DS neurons, we identified distinct spatiotemporal neural dynamics at the single-trial level specific to task-relevant variables. Choice-position selective neural dynamics reflected the positions chosen and was correlated with the trial-to-trial fluctuation of behavioral variables. Choice-pattern selective neural dynamics distinguished whether incoming choice was a repetition or a switch from the previous choice. Our results suggest how the ensembles of M2 and DS process distinct features of decision-related signals at various points in time.
P2-29 Smell of human amniotic fluid*Mamiko Ozaki1-3 Tastuya Uebi2
1Kobe University 2KYOUSEI Science Center for Life and Nature, Nara Women’s University 3Scent fest Co., LTD
Until birth, the foetus grows in the womb filled with amniotic fluid. Although the origin and chemical composition of amniotic fluid has been widely reported, not many studies have focused on its odour or odour components. Therefore, with the consent of our maternal collaborators, we collected several samples of amniotic fluid and attempted to analyse the headspace gases. The odour of amniotic fluid includes 2,4-dimethylheptane, 4-methylheptane, 3-ethylhexane, hexanoic acid, 2,4-dimethyl-1-heptene, etc. However, there tended to be large differences between samples due to individual differences or analysis methods, compared to neonatal head odour, which had a common chemical composition with little individuality. The environmental survival factors for the foetus in the womb are thought to be largely dependent on the amniotic fluid. If the environment enclosed by the amniotic fluid ensures the safety of the foetus, it is possible to assume that the odour factor of the amniotic fluid influences the foetus through its sense of smell. We would like to use this report as a starting point to identify a new role for amniotic fluid.
P2-30 Spatiotemporal analysis of Ca2+ entry and Glutamate release at the retinal bipolar cell ribbon type synapses of goldfish*Tomoko Oshima-Takago1, 2, Hirokazu Sakamoto1, Yukihiro Nakamura1, 3, Shigeyuki Namiki1, Kenzo Hirose1, Masao Tachibana 1, 2, 4, Hideki Takago1, 2
1Dept. of Pharmacol, Grad. Sch. of Med., The Univ. of Tokyo, 2Dept. of Rehab. for Sens. Func., Res. Inst., Nat’l. Rehab. Ctr. for Pers. W/ Disabil., 3Dept. of Pharmacol, Jikei Univ. Sch. of Med., 4Ctr. for Syst. Vis. Sci., Org. of Sci. and Tech., Ritsumeikan Univ.
Sensory ribbon-type synapses continuously process glutamatergic neurotransmission driven by slowly-inactivating Ca2+ current. Previous studies showed that the retinal bipolar cell ribbon synapses of goldfish (Carassius auratus) exhibits kinetically discrete types of glutamate (Glu) release upon long stimulation: fast and slow components of evoked release. For determining Glu release sites for both release components, we established Glu imaging with the enhanced hybrid-type Glu optical sensor targeting the goldfish retinal bipolar cell. Utilizing a combination of Ca2+ and/or Glu imaging, whole-cell voltage-clamp recording, and live-labeling of ribbons, we obtained following results: first, evoked Ca2+ and Glu hot spots, varying in fluorescent intensities, on brief stimuli coincidently occur predominantly at ribbon regions; second, the evoked Glu hot spots on longer stimuli appears to occur at both ribbon and non-ribbon regions; third, spontaneous Glu hot spots occur across the terminal. Thus, the bipolar cell ribbon synapses process sensory signals in spatiotemporally diverse manners presumably to separately convey the contrast and luminance of light.
P2-31 Spinal inhibitory neurons that control rhythmic pectoral fin movements in zebrafish*Yukiko Kimura, Shin-ichi Higashijima
Dept. Creat. Res., ExCELLS, NINS
P2-32 The extraocular circadian clock controls the locomotor activity rhythm in the terrestrial slug, Ambigolimax valentianus
*Shogo Harada, Shin G. Goto
Dept. Biol., Grad. Sch. Sci., Osaka Metropolitan University
Many organisms adapt to periodically fluctuating environments by regulating their activity using an endogenous oscillator known as the circadian clock. Previous studies have revealed that locomotor activity rhythm is regulated by the ocular circadian clock (a circadian clock in the eyes) in some gastropod species but not in other gastropods. Here, we investigated the role of the eyes in the circadian locomotor activity rhythm in the terrestrial slug, Ambigolimax valentianus. First, we found that this species showed a clear nocturnal locomotor activity rhythm under light-dark conditions and a clear circadian rhythm under constant conditions. Next, we removed their eyes and investigated the locomotor activity rhythm of eyeless slugs. Although this species could regenerate its eyes promptly, quantitative analysis of rhodopsin gene expression revealed that eye regeneration took more than 12 days. The eyeless slugs showed a clear circadian locomotor activity rhythm, and the rhythm could be entrained to a non-24-h photoperiod. These results indicate that the extraocular circadian clock controls locomotor activity rhythm. Its photoreceptors are also located extraocularly.
P2-33 The involvement of acetylcholine in the conjugation process in the ciliated protozoan Tetrahymena thermophilaKaho Komatsu1, Yuto Shimada2, *Mikihiko Arikawa3
1Grad. Sch. Integr. Arts Sci., Kochi Univ. 2NIPS, NINS. 3Dep. Biol. Sci., Fac. Sci. Tech., Kochi Univ.
The ciliated protozoan Tetrahymena thermophila undergoes conjugation for sexual reproduction. Washing cells during conjugation induction significantly reduced the number of paired cells, suggesting the presence of an extracellular factor crucial for pair formation. However, this factor remains unidentified. Therefore, in the present study, building on prior experiments conducted on the ciliate Paramecium caudatum, we investigated the involvement of acetylcholine (ACh), a widely recognized neurotransmitter in the nervous systems of higher organisms, in pair formation during Tetrahymena conjugation. When the ACh concentration in the extracellular liquid was increased by adding an ACh analogue or an ACh-degrading enzyme inhibitor during conjugation induction, pair formation was accelerated. In contrast, when the ACh concentration in the extracellular liquid was decreased by adding an ACh-degrading enzyme, pair formation was attenuated. Moreover, the addition of an inhibitor of ACh receptors suppressed pair formation. Based on these results, ACh can be considered as the extracellular factor involved in cell-cell interactions in Tetrahymena conjugation.
P2-34 The roles of corazonin in the body color of the bean bug Riptortus pedestrisLi Xiji1*, Yoshitaka Hamanaka2, Sakiko Shiga2
1International College, Osaka Univ. 2Grad. Sch. Sci, Osaka Univ.
Kobayashi and Numata (1993) first reported photoperiodic influences on body coloration in Riptortus pedestris. Neuropeptide corazonin (CRZ) has been shown to control eye pigment and cuticle melanization in locusts. Although we recently found that CRZ photoperiodically controls reproductive diapause in female R. pedestris, its role in photoperiodic body coloration remains unknown. Here, we focused on cuticle pigmentation and found that short-day females exhibited darker pigmentation on the dorsal abdomen compared to long-day females, whereas there were no significant differences in body color during their nymph stages. Suppressing Crz mRNA expression in 4th instar nymphs via RNA interference caused 5th instar nymphs to exhibit a lighter red-brownish whole body coloration, different from the dark coloration in intact and control bugs. Additionally, dsCrz-treated short-day females were less pigmented on the dorsal cuticle after eclosion, resembling the body color of long-day females. Our findings provide new evidence that melanization of dorsal abdomen cuticle in R. pedestris is photoperiod-dependent and that CRZ mediates this alternating cuticle melanization.
P2-35 Transcription elongation factor ELONGIN regulates cold tolerance in temperature-responsive tail neuronsSho Yabuuchi1, Hiroaki Teranishi2, 3, Toshihiro Iseki2, 3, Natsune Takagaki2, 3, Yohei Minakuchi4, Atsushi Toyoda4, Akane Ohta1-3, Atsushi Kuhara1-3, 5
1Dept. Biol. Facul. Sci & Engineer. Konan Univ., 2Dept.Biol. Grad. Sch. Sci. Konan Univ., 3Inst. of Integral NeuroBiol. Konan Univ., 4National Institute of Genetics, Japan, 5PRIME AMED
We utilized cold tolerance of nematode C. elegans as a model for animal temperature response (Ohnishi et al., Nat commun, 2024). Here we found that the stress responsive transcription elongation factor TCEB-3 was identified as a gene that positively regulates cold tolerance. TCEB-3 is the elonginA known as a conserved transcription elongation factor, and tceb-3 mutant showed reduced-cold tolerance, which was restored by expressing wild-type TCEB-3 in all neurons, but not in muscle cells, intestine. By using transcriptome analysis of tceb-3 mutant, we found a glycerol phosphatase gene (PGPH) acting as positive regulator of cold tolerance, downstream of TCEB-3. An one-cell transcriptome database described that there are 35 neurons expressing both TCEB-3 and the PGPH. Besides, cis-element analysis of tceb-3 promoter indicated that 22 neurons are involved in tceb-3-mediated cold tolerance, and six of these 22 cells express both TCEB-3 and PGPH. Ca2+ imaging revealed that one of the six neurons located at the tail showed temperature responsiveness under cooling stimuli. We are planning to analyze whether known thermosensory pathway activates this tail interneuron.
P1-56 Winter-specific nocturnal activity in the soldier crab Mictyris guinotae*Hiroki Takekata1, Wataru Taira2, Akihiro Takemura3
1Organization for Research Promotion, University of the Ryukyus, 2Ryukyu University Museum (Fujukan), University of the Ryukyus, 3Department of Chemistry, Biology and Marine Science, University of the Ryukyus
The soldier crab Mictyris guinotae is a crab inhabiting the tidal flats, and shows a circatidal rhythm corresponding to the tidal cycle. In addition, the diurnal component was also observed, and some individuals were more active during night, especially in the crabs collected during winter. It is known empirically that M. guinotae emerges on the ground only at night in the field during the winter, suggesting its nocturnality can be induced by a seasonal environmental factor(s). In the present study, we examined whether the nocturnality of M. guinotae is induced by seasonal environmental factors, day length and temperature. The results showed that the crabs collected in summer were active both day and night irrespective of the rearing conditions. On the other hand, the crabs collected in winter showed nocturnal activity under a short-day and low-temperature condition, but not under a long-day and high-temperature condition. These results showed that the soldier crabs show nocturnal activity during winter and can be changed from winter to summer activity pattern immediately, but that the change from summer to winter takes longer time.
