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Zoological Science

Yutaka Okuzaki, Teiji Sota
To understand geographic body size variation in an insect species, various factors including habitat temperature, correlation between life history traits, and food availability must be examined. Carabus (Ohomopterus) japonicus is univoltine, feeds exclusively on earthworms during its larval stage, and shows a clinal body size variation along the habitat temperature gradient in northern Kyushu, Japan. Carabus japonicus occurs at both high and low altitudes; at high altitudes it coexists with a larger species, C...
June 2017: Zoological Science
Luna Yamamori, Kazuya Okuizumi, Chika Sato, Shuhei Ikeda, Haruhiko Toyohara
Scyphozoa, Cubozoa and Hydrozoa are classes in the phylum Cnidaria that undergo metagenesis involving a dramatic morphological transition. In Scyphozoa and Cubozoa, when exposed to species- or strain-specific transition-inducing stimuli, asexually reproducing benthic polyps transform into sexually reproducing planktonic medusae. In Hydrozoa, exposure to species- or strainspecific transition-inducing stimuli causes formation of medusa buds in the polyp's body. In Aurelia aurita (Linnaeus, 1758) (Scyphozoa, Semaeostomeae), polyp-to-jellyfish transition is induced by some simple indole compounds...
June 2017: Zoological Science
Takuya Akiyama, Kunikazu Momose, Manabu Onuma, Fumio Matsumoto, Ryuichi Masuda
The red-crowned crane (Grus japonensis) is recognized internationally as an endangered species. Migratory populations breed in eastern Russia and northeastern China, whereas the resident population inhabits the island of Hokkaido, Japan. Although the population inhabiting Hokkaido had experienced a severe bottleneck by the end of the 19th century, the population size has recovered to about 1500 and continues to increase now thanks to conservation efforts. A previous study reported that no marked genetic differences were seen in the island population, and that the genetic variation of the whole population on Hokkaido was lower than that of the continental population...
June 2017: Zoological Science
Alexey P Kryukov, Liudmila N Spiridonova, Sayaka Mori, Vladimir Yu Arkhipov, Yaroslav A Red'kin, Oleg A Goroshko, Evgeny G Lobkov, Elisabeth Haring
We examined sequences of the mitochondrial control region in magpies (Pica pica) from the entire distribution range and found deep genetic splits into four major lineages: (1) group West (Europe-Siberia), (2) group East (southern Far East), (3) P. p. mauritanica (North Africa), and (4) P. p. hudsonia (North America). These lineages show a geographic pattern corresponding to known subspecies or subspecies groups. Genetic variation within the widely-distributed group West is low and neutrality tests supported a recent expansion scenario...
June 2017: Zoological Science
Yutaro Oku, Tohru Naruse, Hironobu Fukami
Mushroom corals are reef corals of the family Fungiidae, which live in the tropical and subtropical Indo-Pacific region. Recently, most species of this family have been revised taxonomically based on morphological and molecular analyses. However, the phylogenetic position of Cycloseris hexagonalis ( Milne Edwards and Haime, 1848 ) has not been analyzed and remains unclear. This species is believed to show allometric growth by changing its corallum shape from hexagonal in juveniles to irregularly circular with an undulated corallum margin in mature individuals...
June 2017: Zoological Science
Yasuko Washitani, Reiko Hayakawa, Meihua Li, Shozo Shibata
Polymesoda spp., which represent bivalves in the mangrove ecosystem, inhabit the mangrove forests of the Indo-Pacific region. They tend not to be broadly distributed across zones within the mangrove forest, but are instead typically encountered in the mesozone. We conducted field rearing experiments on four plots which were set across a mangrove forest along the Urauchi River of Iriomote Island, from the seaward to landward sides, over a period of 10 months. We compared the survival rates of clams at these plots with different environment for four months...
June 2017: Zoological Science
Taeseo Park, Won Kim
An Asian species of Perinereis, which has been regarded as a local population of a cosmopolitan species P. cultrifera ( Grube, 1840 ) (type locality: Italy), is described as a new species, P. euiini., based on Korean specimens. This new species is distinguishable from P. cultrifera and other similar species such as P. floridana ( Ehlers, 1868 ) (type locality: USA), P. anderssoni Kinberg, 1866 (type locality: Brazil), and P. helleri ( Grube, 1878 ) (type locality: Philippines) by the character combination of the absence of lateral group of paragnaths in area III on the proboscis, the presence of small notopodial prechaetal lobe in anterior parapodia, and the greatly expanded dorsal ligule in posterior parapodia...
June 2017: Zoological Science
Takayoshi Otsuka, Hiroyuki Takeda
The pancreas plays important roles in the regulation of blood glucose, and is a well-studied organ in mammals because its dysfunction causes serious disorders, such as diabetes mellitus. However, mammals have the limited capacity for tissue regeneration in their organs, including pancreas. Fish may be an attractive model for regeneration studies, as fish exhibit a greater capacity for regeneration than do mammals. To elucidate the regenerative capacity of pancreatic β cells in medaka, we generated transgenic lines, in which β cells can be specifically ablated using the nitroreductase (NTR)/metronidazole (Mtz) system...
June 2017: Zoological Science
Mi Ae Kim, Young Chang Sohn
Nuclear receptor (NR) interacting proteins, such as coactivators and corepressors, play a crucial role in specifying the transcriptional activity of the receptor. However, little is known about the functional features of the NR coregulators in marine invertebrates. Using the yeast two-hybrid screening method, a sea urchin oocyte cDNA library was screened for proteins that interact with the ligand-binding domain of human RXRα (hRXRα) as the bait protein in the presence of 9-cis retinoic acid. Here, we describe IQ motif containing protein D (IQCD) as an RXR-interacting coactivator...
June 2017: Zoological Science
Kaori Hanazaki, Morihiko Tomozawa, Yutaro Suzuki, Gohta Kinoshita, Masanobu Yamamoto, Tomohisa Irino, Hitoshi Suzuki
Reliable estimates of evolutionary rates of mitochondrial DNA might allow us to build realistic evolutionary scenarios covering broad time scales based on phylogenetic inferences. In the present study, we sought to obtain estimates of evolutionary rates in murine rodents using calibrations against historical biogeographic events. We first assumed that land-bridge-like structures that appeared intermittently at glacial maxima with 100,000-year intervals shaped the divergence patterns of cytochrome b (Cytb) sequences (1140 bp) of the larger Japanese wood mouse Apodemus speciosus...
June 2017: Zoological Science
Masahiko Tanahashi, Xian Ying Meng, Takema Fukatsu
Bell-shaped ciliates of the subclass Peritrichia, such as Vorticella, Carchesium and Epistylis, are commonly found in freshwater and other aquatic environments, either solitary or colonial. Peritrichs attach to a substratum via a contractile or non-motile stalk, and collect food particles by water current using ciliary rows around the edge of the bell, called the peristome. Some peritrichs are epibiotic and ectocommensalistic associates of aquatic insects and other animals, settling on the surface of their specific hosts...
June 2017: Zoological Science
Ayano Otani, Tadaaki Nakajima, Tomomi Okumura, Shiro Fujii, Yasuhiro Tomooka
Many molluscs perform sex reversal, and sex hormones may be involved in the process. In adult scallops, Patinopecten yessoensis, gonadotropin releasing hormone and 17β-estradiol (E2) are involved in male sexual maturation, however, little is known about the effects of E2 and testosterone (T) on the gonadal differentiation in young scallops. In the present study, scallop gonadal development was analyzed to determine the sex reversal stage in Funka bay, and effects of E2 and T were examined. In Funka bay, almost all scallops were male at month 12...
April 2017: Zoological Science
Miki Yamamoto, Koji Nishimura, Sakiko Shiga
The eclosion gate in insect development is controlled by the circadian clock and hormonal cascade. To study mechanisms underlying the eclosion gate, we examined eclosion-timing signals from the circadian clock, and the role of 20-hydroxyecdysone in the eclosion gate of the flesh fly, Sarcophaga crassipalpis. Phase responses of the eclosion rhythm were examined by applying a low-temperature pulse in the day prior to the first eclosion peak. A low-temperature pulse applied about 5.4 h before eclosion advanced an eclosion peak by 0...
April 2017: Zoological Science
Kazumi Shimaoka, Yoshiko Mukumoto, Yoko Tanigawa, Tohru Komiya
Xenopus vasa-like gene 1 (XVLG1), a DEAD-Box Helicase 4 (DDX4) gene identified as a vertebrate vasa homologue, is required for the formation of primordial germ cells (PGCs). However, it remains to be clarified when and how XVLG1 functions in the formation of the germ cells. To gain a better understanding of the molecular mechanisms underlying XVLG1 during PGC development, we injected XVLG1 morpholino oligos into germ-plasm containing blastomeres of 32-cell stage of Xenopus embryos, and traced cell fates of the injected blastomere-derived PGCs...
April 2017: Zoological Science
Noriyuki Takahashi, Wataru Tarumi, Naomi Hamada, Bunpei Ishizuka, Masanori T Itoh
The thiazine dye toluidine blue (TB) is well known to stain mast cells and hyaline cartilage metachromatically, and thus is mostly often used for their identification. However, TB is not suitable for counterstaining in immunohistochemistry, because of its high-background staining in the cytoplasm of other cell species and in extracellular structures. To expand the knowledge about dyestuffs staining mast cells in consideration with their usage in immunohistochemistry, we determined the stainability of several thiazines and oxazines, which are structurally related compounds to TB, using sections of mast cell-containing tissues...
April 2017: Zoological Science
Mikako Wada, Kazuko Fujitani, Kei Tamura, Shuuji Mawaribuchi, Yosuke Kamata, Nobuhiko Takamatsu, Michihiko Ito
The African clawed frog Xenopus laevis has a female heterogametic ZZ/ZW-type sex-determining system. We previously discovered a W-linked female sex-determining gene dm-W that is involved in ovary formation, probably through the up-regulation of the estrogen synthesis genes cyp19a1 and foxl2. We also reported that a unique "mass-in-line structure", which disappears from ZZ gonads during early testicular development, might serve as the basis for ovary differentiation in ZW gonads. However, the molecular mechanisms underlying early masculinization are poorly understood...
April 2017: Zoological Science
Jun J Sato, Yurina Tasaka, Ryoya Tasaka, Kentaro Gunji, Yuya Yamamoto, Yasushi Takada, Yasushi Uematsu, Eiichi Sakai, Takashi Tateishi, Yasunori Yamaguchi
To study the effects of post-glacial isolation by islands on population genetic diversity and differentiation of the large Japanese field mouse, Apodemus speciosus, we examined partial nucleotide sequences of the mitochondrial Dloop region (ca. 300 bp) in 231 individuals collected from islands in the Seto Inland Sea and adjacent regions on Honshu and Shikoku Islands in the western part of the Japanese archipelago. Molecular phylogenetic and network analyses showed that haplotypes in each island tended to form monophyletic groups, while those in Honshu and Shikoku (the major Japanese islands) showed scattered relationships and were connected with island haplotypes...
April 2017: Zoological Science
Jae-Young Song, Masafumi Matsui, Takashi Matsuki, Kanto Nishikawa, Kyo-Soung Koo, Hong-Shik Oh
Using preserved specimens, we studied the basic life history of the topotypic population of the unique Asian plethodontid salamander, Karsenia koreana. Of 51 individuals examined, 11 males and 13 females were judged as mature from the development of gonads. The ovarian eggs were large (diameter 3.7-4.8 mm) and yellow to orange in color, and the clutch size was about 8-10. These values approximate those of actually spawned eggs recently reported. Skeletochronological analyses revealed the average age of males (5...
April 2017: Zoological Science
Takafumi Nakano
A quadrannulate species of Orobdella, O. kanaekoikeae sp. nov., from the mountainous region of Shikoku, Japan is described. This new species is small with a body length of mature individuals reaching only ca. 5 cm. Phylogenetic analyses using nuclear 18S, histone H3, mitochondrial cytochrome c oxidase subunit I, tRNA(Cys), tRNA(Met), 12S rRNA, tRNA(Val), 16S rRNA, tRNA(Leu), and NADH dehydrogenase subunit 1 markers showed that O. kanaekoikeae is a sister species of the quadrannulate small O. brachyepididymis...
April 2017: Zoological Science
Keiichi Kakui, Yoshinobu Hayakawa, Haruo Katakura
We investigated the life cycle of the tanaidid Zeuxo sp. 1 (Crustacea: Peracarida: Tanaidacea), which lives epiphytically in dwelling tubes on the algae Sargassum spp. and Neorhodomela aculeata in Oshoro Bay, Hokkaido, Japan. We obtained data on its population size distribution, age structure, and reproductive phenology through monthly sampling from April 2011 to June 2012. From these data, we detected an overwintering group (F0) that arises from mancae that are released in autumn, overwinters, reproduces the following spring, and then disappears...
April 2017: Zoological Science
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