Polyneoptera is an assemblage of 11 insect orders consisting of lower neopteran insects. The interordinal relationships within Polyneoptera remain highly controversial and ancient rapid radiations are thought to be responsible. Phasmatodea, whose phylogenetic position among Polyneoptera is quite unstable, has been thought to be a key taxon to resolve the polyneopteran phylogeny. We determined the full-length sequence of the mitochondrial genome of a stick insect, Extatosoma tiaratum, and explored the phylogeny of polyneopteran insects using nucleic acid as well as amino acid sequences from the mitogenome. Our analyses recovered a close relationship between Phasmatodea, Mantophasmatodea and Grylloblattodea. Dictyoptera was placed as a sister to this group. The monophyly of Orthoptera was confirmed and Plecoptera was placed as a sister group of this order. Six clades are recovered within Phasmatodea in this study and most of them challenge the conventional classification system.

抄録全体を表示

All parts of Morus alba offer great therapeutic potential, but are they beneficial to the whole organism, particularly with respect to aging? We evaluated the effect of an ethanol extract of mulberry leaves on the model organism Caenorhabditis elegans. The extract significantly extended mean lifespan by 17% from 17.6 to 20.6 days. This compares well to the effect of ethosuximide, a drug used to treat seizures in humans, which increased adult lifespan by 35%. This novel activity suggests that mulberry leaves have the potential to retard the aging process.

抄録全体を表示

A phylogenic analysis of mariner-like elements (MLEs) of the obscura species group in the genus Drosophila was performed to elucidate the evolution of MLEs in closely related species. MLEs were identified mainly from genomes of species belonging to the affinis species subgroup. These MLEs showed higher degree of sequence similarity and more recent divergence time from related species in comparison with Adh genes. Based on these observations, the conclusion was made that a certain type of mariner element invaded an ancestral species of the affinis species subgroup by horizontal transfer and was subsequently inherited vertically.

抄録全体を表示

Scalloped (Sd) and Vestigial (Vg) form a transcription factor complex that plays a central role in the wing development of Drosophila melanogaster. Sd provides DNA-binding ability through a conserved TEF-1, TEC-1, ABAA domain (TEAD), whereas Vg is required in order to confer transcription activity to the Sd-Vg complex. The present study reported the results of functional analysis of the sd orthologue (Td-sd) in the firebrat, Thermobia domestica. As T. domestica is a basal apterygote insect, analysis of its wing genes could potentially provide clues to understanding insect wing evolution. Initially, embryonic RNAi analysis was performed using previously established techniques. Unfortunately, the effect of Td-sd RNAi during embryonic development could not be analyzed due to phenotype lethality. Therefore, in order to explore Td-sd function during post-embryonic development, double-stranded RNA was injected into a T. domestica nymph. This resulted in specific reduction of the antenna, cercus and caudal filament, although formation of the paranotum was not affected. These results demonstrated novel function of sd in two types of ventral appendages, the antenna and the cercus, as well as in a non-appendage outgrowth, the caudal filament. The nymphal RNAi method established for use in T. domestica in the present study could serve as a helpful tool in understanding the evolution of characteristic traits in insects.

抄録全体を表示

We have developed a simple technique to fabricate tubes of hornet (Vespa) silk protein. In this technique, a column of homogeneous hornet silk hydrogel uniformly forms around a straight wire core that serves as an inert scaffold. The tube is then thoroughly dried. During drying, the hydrogel was isotropically contracted toward the core wire. Finally, the wire is pulled out of the dried gel and the gel tubes are complete. Examination showed that the inner and outer diameters of the gel tubes were uniform and that the inner and outer surfaces were smooth. The silk content in the hydrogel, which can be controlled by adjusting the concentration of silk in the solution before gelation, affected the diameter and wall thicknesses of the tubes as well as their physical properties, including tensile and compression strength. When the gel tube was rehydrated, the tube showed some degree of swelling and flexibility; however, it did not return to the original hydrogel form. Under uniaxial tension, the rehydrated tube could show uniform twofold or threefold stretching. Moreover, no conformational change and no thermal degradation occurred in the dried hornet silk gel tube during incubation at 180°C for 40min. This indicates that the dried hornet silk gel tube can withstand dry heat sterilization (180°C for 30min), which makes it suitable for use in medical applications.

抄録全体を表示