Photosymbiosis occurs in symbiotic relationships between heterotrophs and photosymbiotic organisms, where a photosynthetic symbiont provides photosynthate to a host. While almost all known host animals are invertebrates, experiments have determined that artificial symbiotic relationships can be established between vertebrates and phototrophs. The ability to generate photosymbiotic relationships in vertebrates has important applications for medical treatments and commercial resource production.
Clerodendrum viscosum is a traditionally used medicinal plant. The present study aimed to analyze cell cycle delay, pro-metaphase arrest, and c-metaphase inducing effects of the petroleum ether fraction (AQPEF) of leaf aqueous extract of C. viscosum (LAECV). The LAECV was fractionated with petroleum ether and its metaphase arrest, cell cycle delay, and c-metaphase inducing activities were tested on A. cepa root tip cells. The AQPEF induced cell cycle delay, and colchicine like metaphase, c-metaphase, in A. cepa root tip cells. Thus, the present study explores AQPEF as an active fraction of LAECV having metaphase arresting, cell cycle delay, and c-metaphase inducing potentials.
Maesa macrophylla (Wall.) A. DC. is a traditionally used medicinal plant. The present study aimed to analyze the mitotic index reducing and cytotoxic potentials of the leaf aqueous extract of M. macrophylla (LAEMM) in Allium cepa root tip cells. The 48-h aged A. cepa roots were treated with LAEMM (0–4 mg mL−1) for 2–72 h and the root growth retardation (RGR), mitotic index (MI) reduction, and mitotic abnormalities (MAs) like sticky and vagrant chromosomes, anaphase bridge, polar deviation at metaphase or anaphase, etc. were analyzed. The LAEMM induced concentration and time-dependent RGR effects, MI reduction, and the formation of different types of MAs. Thus, the present work explored here cytotoxic effects of LAEMM in A. cepa root tip cells.
Scutellaria discolor Colebr. is a traditionally used annual herb that occurs in the Himalayan regions of India. The present study aimed to analyze the cytotoxic effects of S. discolor aqueous extract on Allium cepa root tip cells. The equal-sized roots, 48 h aged, were treated with the aqueous extract of S. discolor (AESD) (0.5–4 mg mL−1) and colchicine (0.4 mg mL−1) for 4 h continuously and then recovered for 16 h (4+16 h R) in distilled water. The AESD induced colchicine-like mitotic abnormalities; sticky chromosome, vagrant and laggard chromosomes, chromosomal fragments, anaphase bridges, stellate anaphase, micronucleus, and polyploidy, indicating it may have like colchicine prospective therapeutic and cytotoxic applications.
Clerodendrum inerme is a widely used medicinal plant in tropical and subtropical regions of the world. The present study aimed to analyze the micronuclei (MN) and polyploid (PP) cell-inducing potentials of the leaf aqueous extract of C. inerme (LAECI) in Allium cepa root tip cells and compared with colchicine induced MN and PP in A. cepa root tip cells. The LAECI induced increased frequency of MN and PP in root tip cells at 4 h treatment followed by 32 h water recovery and the effects were found to be comparatively higher than the colchicine effects. Thus, LAECI may contain bioactive phytoconstituents having MN and PP inducing effects on A. cepa root tip cells, suggesting its colchicine-like application in karyotyping and plant breeding programs.
Chromosomal aberration assessment is an important index in mutation breeding for determining the mutagen potency, which helps to deduce an optimum level of mutagen dose tolerable by the species. In this study, the genotoxic effects of ethyl methane sulphonate (EMS), methyl methane sulphonate (MMS) sodium azide (SA), and colchicine were studied on the meiotic cell division of Triticum aestivum L. The results demonstrated that these chemical mutagens cause various types of meiotic anomalies, such as univalents, multivalents, chromosome stickiness, unoriented chromosomes, precocious chromosome movements, chromatin bridges, lagging chromosomes, acentric fragments, and micronuclei. A substantial influence of chromosomal aberrations on the post-meiotic product was also experienced. Irregular sporads in the form of triads, dyads, monads, and polyads, along with regular tetrads were witnessed. The maximum chromosomal aberrations were observed at higher concentrations of the mutagenic treatments. The highest proportion of pollen mother cells showing meiotic aberrations was induced by EMS followed by colchicine, MMS, and SA. The frequency of fertile pollens was seen to decline from control to the highest concentration of mutagens due to anomalies of preceding stages. In addition, mutagenic treatments decreased germination and survival percentage as well. The treatment concentrations ranging from 0.2–0.3% were found favorable in creating significant cytogenetic variability and average lethality and thus, could be beneficial in future cytological and mutation breeding programs.
Crinum asiaticum is a well-known medicinal plant of the family Amaryllidaceae. The present study aimed to analyze the cytotoxic and cytostatic effects of leaf aqueous extract of C. asiaticum (LAECA). The 48-h aged Allium cepa roots were treated with LAECA (0.25–2.0 mg mL−1) and root growth inhibition, mitotic index (MI), chromosomal and cytological aberrations were analyzed. The LAECA induced a concentration-dependent root growth retardation, decreased MI, and increased the various cytological aberrations, like giant cells, hyperchromasia, sticky chromosome, chromosome break, polar deviation, and binucleated cells in A. cepa root apical meristem. Thus, the present study explores the cytotoxic and cytostatic effects of LAECA.
The genus Medicago encompasses several significant and economically important annual and perennial taxa, each possessing distinct cytogenetical characteristics. Existing reports on chromosome numbers and karyology of the genus are quite intriguing and indicate the possible existence of underlying genetic variations. The present investigation on 18 taxa included three Lucerne varieties for the study of their chromosomal complements and karyological evolution. Twelve out of the 18 taxa analyzed were observed to be diploids with ten species having chromosome number of 2n=16 and two, Medicago constricta and M. rigidula contained 2n=14 chromosomes each. The remaining four species showed chromosome numbers of 2n=30 and 2n=32. Nucleolar organizing regions (NORs) have been a characteristic feature of the first pair of chromosomes in all the species analyzed. While the majority of the species analyzed show a basic number of x=8, the polybasic nature of the genus becomes apparent with x=7 and 8 and occurrence of polyploid series with 2n=14, 16, and 32. No heteromorphic pairs were observed in the chromosome complements of any of the analyzed species. This, along with the predominance of submetacentric chromosomes in the karyotypes validates the opinion that no significant structural changes have occurred to alter the karyotypes in the evolution of the genus. In the present study, numerical changes were encountered in M. arborea, M. scutellata, M. rugosa, and all three varieties of M. sativa.
Two accessions were recognized in the species of Cousinia lactifelora Rech. f. Accession A had n=12 and accession B showed the presence of 0 to 10 B-chromosomes at various stages of meiosis in addition to n=12 chromosomes. These B-chromosomes were smaller than the A-chromosomes and there existed as univalent and bivalents. Association of B-chromosomes with A-chromosomes occurred in less than 0.5% at metaphase I. This phenomenon is reported here for the first time. Analysis of chromosome behavior at meiosis showed that the presence of B-chromosomes decreases chiasma frequency in A-chromosomes. The effects of B-chromosomes in odd and even numbers are different. Comparison between plants with B-chromosomes and plants without B-chromosomes suggested that the effect of B-chromosomes was on pollen stainability. It seems that the presence of B-chromosomes may be responsible for the reduction of pollen stainability in C. lactiflora.
The karyology of five species of Boesenbergia (B. collinsii, B. pulcherrima, B. rotunda, B. thorellii and B. xyphostachya) (Zingiberaceae) in Thailand are investigated. The chromosome number and karyotype formula of the five species are 2n=20 (8m+10sm+2st) in B. collinsii, 2n=36 (8m+18sm+10st) in B. pulcherrima, 2n=38 (18m+14sm+6st) in B. rotunda, 2n=38 (30m+8sm with one satellite) in B. thorellii and 2n=22 (6m+6sm+10st with two satellites) in B. xyphostachya, respectively. Three species of B. collinsii, B. pulcherrima and B. thorellii have new chromosomal counts. The fundamental number (NF) and karyotype of all species in this study were reported for the first time. Satellites were observed in the chromosome of B. thorellii and B. xyphostachya.
The genus Epilobium, belonging to the family Onagraceae, is an endemic Iranian medicinal plant that has illustrated a vast variety of pharmacologically important metabolites. The cytological characteristics of eight species collected from different regions of Iran were assessed for the first time. All species analyzed were diploid, six species (E. hirsutum, E. parviflorum, E. roseum, E. algidum, E. anatolicum, and E. confusum) had 2n=2x=36 chromosomes, except for two species (E. frigidum, E. lanceolatum) had 2n=2x=38 chromosomes with unequal in size. The mean chromosome length of all species was 0.53 µm, ranging from 0.46 to 0.64 µm. Propidium iodide (PI) and Solanum lycopersicum cv. Stupicke (2C DNA=1.96 pg) as an internal standard were used for flow cytometric survey of genome size and the levels of ploidy. The mean genome size (2Cx DNA) of all species was 0.86 pg, varied from 0.74 to 0.90 pg, confirming inter-specific variation and revealing considerable variation in genome size within each species. Valuable information on cytogenetics can be used in some research fields, including polygenetic analysis, taxonomic relationships, evolutionary characteristics, ecology, plant growth, and development of plant breeding.
In this study, cytogenetic toxicity of colchicine in microsporocytes of hard wheat (Triticum durum Desf.) was evaluated. Colchicine treatments revealed the induction of various chromosomal abnormalities in gametic cells which includes chromatin stickiness, unoriented chromosomes, univalents, laggards, bridges, and micronuclei. These abnormalities increased along with increased colchicine concentrations. Simultaneously, the study also deals correlation of overall cytological aberrations with the frequency of seed germination, plant survival, and pollen fertility. Chromosome stickiness along with spindle disturbances, laggards, chromatin bridges, irregular chromosome distribution, and abnormal tetrads are the main causes that lead to a reduction in pollen fertility percentage found in colchicine-treated populations. Furthermore, the colchicine-induced chromosome aberrations caused a significant decline in seed germination and plant survival with the increasing colchicine concentrations. The present findings reveal the potential of colchicine in inducing alterations in chromosome structure and behavior thereby enhancing the genetic diversity in hard wheat. As a result, colchicine could be efficiently exploited for isolating novel and promising mutants in segregating generations.
Microsatellite sequences in the genome are transmitted to the offspring according to Mendel’s law and then can be traced in genetic crosses in the levels of species or individuals. To detect heterozygous microsatellite markers in Pinus wallichiana, we performed PCR using specific primer sets for RPS150 and RPS160 loci. The RPS150 direct sequence in the upstream of (gat)3 (gat) was homogenous with high Phred quality scores and the following 3′ sequence included multiple nucleotide sequences with lower Phred quality scores. On the other hand, in P. wallichiana RPS160 sequence, (acag)3gcag (acag)3 was intervened between 5′ and 3′ sequences with high Phred quality scores. These results suggest that the RPS160 locus of the specimen analyzed in this study is homozygous, whereas the RPS150 locus is heterozygously consisting of at least two alleles with different nucleotide lengths, as was reported in P. pumila.
Sandwich freezing is a method of rapid freezing by sandwiching biological specimens between two metal disks and has been used for observing exquisite, close-to-native ultrastructure of living yeast and bacteria after freeze-substitution. This method was also useful for preserving the clear and natural ultrastructure of glutaraldehyde-fixed microorganisms, cultured cells, and human tissues. In the present study, this method was used to observe the fine structure of animal tissues for the first time and succeeded in producing clear, exquisite images of mouse heart, liver, and pancreas ultrastructure. The high-quality images obtained in the present study demonstrate that this technique can be applied widely in the field of ultrastructure research.
We investigated morphological changes of mitochondria and the actin cytoskeleton in the yeast Saccharomyces cerevisiae during diauxic growth and glucose depletion culture. S. cerevisiae exhibits diauxic growth during aerobic culture in a medium containing glucose as a carbon source. We demonstrated that mitochondria in budded cells maintain a tubular morphology at the log phase, but begin to fragment at the diauxic shift phase, in which the metabolism in cells switches from fermentation to respiration due to glucose depletion. On the other hand, the actin cytoskeleton exhibited a polarized distribution in budded cells at the log phase but rapidly depolarized at the diauxic shift phase. The fragmentation of mitochondria and depolarization of the actin cytoskeleton also occurred when cells at the log phase were transferred into a glucose-free medium. In these studies, we found that rapid Dnm1p-dependent fragmentation of mitochondria occurs via glucose depletion. In addition, the results suggest that the changes in mitochondrial morphology and in the polarity of the actin cytoskeleton are independent of each other.
Mitochondrial DNA (mtDNA) is uniparentally inherited in most sexual eukaryotes called maternal/uniparental inheritance. It is well known that selective elimination of paternal mitochondria and digestion of paternal mtDNA are important to this process. However, little is known about the control of maternal mitochondrial proliferation. In the isogamous Physarum polycephalum, haploid myxamoebae act as gametes. When two myxamoebal strains with different mating types are mated, mtDNA is inherited from only one strain, defined as the maternal strain. Here, we developed a method to distinguish uniparental mitochondria in zygotes of P. polycephalum by chemical staining and investigated the proliferation of maternal and paternal mitochondria during the selective digestion of mitochondrial nucleoids (mt-nucleoids) in paternal mitochondria. We stained the myxamoebae with MitoTracker Red CMXRos (MTR) or MitoTracker Green FM (MTG). MTG-stained mitochondria more specifically than MTR. When the AI35 strain was crossed with the MTG-stained DP246 strain and mtDNA was stained with N-aryl pyrido cyanine 3, mt-nucleoids in mitochondria derived from DP246 became shorter in the zygotes 3 h after crossing. There was no significant difference in the number of mitochondria derived from both AI35 and DP246 in early zygotes, but the number of mitochondria derived from AI35 proliferated 1.7-fold from 3 to 5 h after crossing. Similar results were obtained when MTG-stained AI35 crossed with DP246. These results indicate that the proliferation of mitochondria derived from AI35 rapidly occurred after the initiation of digestion of mt-nucleoids derived from DP246. Our results suggest the possibility of controlling the mechanism of the selective proliferation of maternal mitochondria during zygote formation for uniparental inheritance.
Previous chromosome information is restricted to nine species in the Asian Begonia sect. Petermannia. We present here the first chromosome counts for 15 taxa and the first karyotype analyses for 14 taxa in sect. Petermannia in addition with a species in sect. Haagea. Among ca. 460 species in sect. Petermannia, chromosome numbers of 24 taxa are available together with the present and previous reports. Among 24 taxa, they show diverse chromosome numbers with 2n=24–28, 28, 30, 36, and 44. Among 12 taxa with 2n=30 analyzed, two species show the new karyotype for 2n=30=16m+14sm(st)2sm in Asian Begonia in addition to 2n=30=8m+22sm(st)2sm of nine species and 2n=30=12m+18sm(st)2sm of one natural hybrid. We discussed the chromosome evolution for 2n=30 in Asian Begonia among sections Petermannia and Haagea in this study, and sections Baryandra, Coelocentrum, and Diploclinium reported earlier.
Seafloor resource development in the future is expected to be accompanied by the mining of metal ores, as these sulfide ores contain valuable metals. However, the mining process is detrimental to marine oceanic environments. As a precautionary approach, innovations in the collection of environmental baseline data and new onboard assessment methods for marine environmental impacts are required. Due to the low cell density in open ocean water, techniques for rapid impact assessment of seawater without sample concentration are required. The purpose of this study was to establish a heavy metal impact assessment system for seawater samples of marine microbes using a portable flow cytometer, On-chip Sort. We established a protocol for detecting heavy metal-induced damage to cells via propidium iodide (PI) staining using algal culture strains (Bathycoccus prasinos NIES-2670, Synechococcus sp. NIES-969, Prochlorococcus sp. NIES-2885, and Cyanobium sp. NIES-981) obtained from the marine environment maintained at the Microbial Culture Collection of the National Institute for Environmental Studies, Tsukuba, Japan. Results showed that PI staining could detect the effects of heavy metals on cells. The proportion of PI-positive cells increased with an increase in the concentration of heavy metal mixture or copper exposure. Compared to cyanobacteria, damaged cells of eukaryotic algae were detected. Therefore, the effects of heavy metals on both eukaryotic and prokaryotic algae can be rapidly assessed via PI-based flow cytometry using samples containing low cell densities.
The karyological results of Stevia rebaudiana introduced in the Primorye region (Far-east of Russia) are presented. S. rebaudiana has a chromosome number of 2n=2x=22 with a karyotype formula of 8m+2sm+1st. The chromosome size is very short (1.1–3.1 µm). The relative length of chromosomes varies from 5.1 to 16.16%. The centromere index (CI) varies from 15 to 49%. An interphase nucleus of S. rebaudiana has one or two nucleoli, which suggests the presence of one pair of nucleolar chromosomes. The clonal propagation method provides a high multiplication rate and also preserves these plants in vitro within a cold period. S. rebaudiana has adapted to the new ecological niche on a constant chromosomal number within the genotype reaction norm.
Karyotype data, male meiosis and pollen fertility of endangered Phlomoides superba (Royle ex Benth.) Kamelin & Makhm., a plant of much medicinal, veterinary and ornamental value was studied. This study is the first report of karyotype and detailed male meiosis in the species. The species exist at the diploid level with 2n=22 chromosomes. The cells were stained with acetocarmine and a standard squash technique was followed to study karyotype and male meiosis in the species. The chromosomes size shows a gradual decrease from 5.25 to 3.42 µm with karyotype formula 2n=16m+6sm. P. superba shows an abnormal meiotic course with anomalies such as early and late disjunction, chromatin stickiness, formation of laggards, chromatin bridges, etc. affecting approximately 17.78% of the total PMCs undergoing the process of reduction division. However, high pollen fertility was seen despite such abnormalities.