Time filter

Source Type

Hirata D.,Hokkaido University | Mano T.,Hokkaido Research Organization | Abramov A.V.,Russian Academy of Sciences | Baryshnikov G.F.,Russian Academy of Sciences | And 8 more authors.
Molecular Biology and Evolution

To further elucidate the migration history of the brown bears (Ursus arctos) on Hokkaido Island, Japan, we analyzed the complete mitochondrial DNA (mtDNA) sequences of 35 brown bears from Hokkaido, the southern Kuril Islands (Etorofu and Kunashiri), Sakhalin Island, and the Eurasian Continent (continental Russia, Bulgaria, and Tibet), and those of four polar bears. Based on these sequences, we reconstructed the maternal phylogeny of the brown bear and estimated divergence times to investigate the timing of brown bear migrations, especially in northeastern Eurasia. Our gene tree showed the mtDNA haplotypes of all 73 brown and polar bears to be divided into eight divergent lineages. The brown bear on Hokkaido was divided into three lineages (central, eastern, and southern). The Sakhalin brown bear grouped with eastern European and western Alaskan brown bears. Etorofu and Kunashiri brown bears were closely related to eastern Hokkaido brown bears and could have diverged from the eastern Hokkaido lineage after formation of the channel between Hokkaido and the southern Kuril Islands. Tibetan brown bears diverged early in the eastern lineage. Southern Hokkaido brown bears were closely related to North American brown bears. © 2013 The Author. Source

Kitao N.,Asahikawa University | Fukui D.,Asahikawa Municipal Asahiyama Zoological Park and Wildlife Conservation Center | Shibata H.,Morinaga Institute of Biological Science Inc. | Saito M.,Tenshi College | And 2 more authors.
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology

Leptin is an adipocyte-derived peptide hormone that acts on the brain and regulates food intake and energy balance. Several previous reports have suggested that overwintering raccoon dogs Nyctereutes procyonoides are able to control their adiposity efficiently, but the contribution of leptin to weight regulation in these animals remains unclear. To study the seasonality of overwintering raccoon dogs as well as the effects of fasting on them, serum leptin levels were investigated using a newly established canine leptin-specific enzyme-linked immunosorbent assay (ELISA) kit. Of the nine animals studied, five were fed and four were fasted (deprived of food for 2 months in winter). Blood samples and body fat weights were monitored once a month throughout the experimental period (July 2007-March 2008). Leptin concentrations obtained by ELISA were significantly higher than and had a positive correlation with those obtained by previously used multispecies radioimmunoassay (RIA) kits. Moreover, ELISA showed a clearer correlation between the body fat weight and leptin levels compared with RIA, suggesting the efficacy of canine leptin-specific ELISA kit for leptin estimation in raccoon dogs. Autumnal fattening was observed in both groups of animals, but the wintertime loss of adipose tissue was more obvious in the fasted group. Serum leptin concentrations determined by ELISA showed seasonal changes without significant differences between the fed and fasted animals. Therefore, high levels of leptin may be responsible for the suppression of feeding behavior in raccoon dogs before winter. Copyright © 2010 Wiley-Liss, Inc., A Wiley Company. Source

Fukui D.,Asahikawa Municipal Asahiyama Zoological Park and Wildlife Conservation Center | Fukui D.,Rakuno Gakuen University | Nagano M.,Hokkaido University | Nakamura R.,Asahikawa Municipal Asahiyama Zoological Park and Wildlife Conservation Center | And 7 more authors.
Journal of Reproduction and Development

Artificial insemination (AI) can help to avoid inbreeding and genetic degeneration for sustaining genetically healthy populations of endangered species in captivity. Collection of a sufficient quantity of viable sperm is an essential first step in the AI process. In the present study, we examined the effects of frequent electroejaculation on semen characteristics in a Siberian tiger. We collected semen in all 17 trials during 6 breeding seasons (6 years). The mean number of sperm and the percentage of motile sperm were 294.3 ± 250.2×106/ejaculate and 82.4 ± 11.4%, respectively. The number of motile sperm tended to increase during frequent electroejaculation in the same breeding season. Semen collection by electroejaculation can be performed effectively up to the fourth sequential ejaculate, which contained the most sperm in the study. In conclusion, frequent collection of sperm by electroejaculation from tigers may be effective for collection of a large number of motile sperm. © 2013 by the Society for Reproduction and Development. Source

Fukui D.,Asahikawa Municipal Asahiyama Zoological Park and Wildlife Conservation Center | Fukui D.,Rakuno Gakuen University | Takahashi K.,Hokkiado Government Kamikawa General Subprefectural Bureau | Kubo M.,Hokkiado Government Kamikawa General Subprefectural Bureau | And 7 more authors.
Journal of Wildlife Diseases

An outbreak of salmonellosis in wild passerines caused mass mortality of Eurasian Tree Sparrows (Passer montanus) in Hokkaido, Japan, 2005-06; however, the etiology was poorly understood. In winter 2008-09, sparrow mortality again occurred in Hokkaido, and 202 deaths in 100 incidents at 94 sites were reported. We conducted a comprehensive investigation to evaluate the cause and impact on sparrow populations. We collected 26 carcasses at 13 sites, including a zoological park. In addition, Salmonella screening of zoo animals was conducted as a biosecurity measure. Salmonella Typhimurium was isolated from multiple organs in all examined sparrows; they were diagnosed with septicemic salmonellosis. Eleven sites (85%) were related to wild bird feeding and six of eight sparrow fecal samples, including from the zoo, were S. Typhimuriumpositive. No infection was detected in zoo animals. Isolates belonged to three phage types: DT40 (88%), DT110 (8%), and DT120 (4%). Pulsed-field gel electrophoresis patterns were the same in all isolates, regardless of phage type. Biochemical characteristics and antibiotic-resistance profiles of DT40 were similar in all isolates, indicating a single origin. The mortality was likely associated with that in 2005-06 because the isolates had the same profiles. Tissue levels of sodium, calcium, and magnesium (the main components of chemical deicer suspected to be the major cause of poisoning deaths in 2005-06 mortality) were not higher in the affected sparrows. We conclude that an emerging epidemic infection with S. Typhimurium DT40 related to bird feeding was the cause of sparrow mortality in 2008-09 and suggest that this causative strain is host-adapted to sparrows in Japan. The mortality might have had some impact on the local population, but its influence was limited. © Wildlife Disease Association 2014. Source

Sakaguchi S.,Kyoto University | Shojima T.,Kyoto University | Fukui D.,Asahikawa Municipal Asahiyama Zoological Park and Wildlife Conservation Center | Miyazawa T.,Kyoto University
Journal of General Virology

T-lymphotropic feline leukemia virus (FeLV-T), a highly pathogenic variant of FeLV, induces severe immunosuppression in cats. FeLV-T is fusion defective because in its PHQ motif, a gammaretroviral consensus motif in the N terminus of an envelope protein, histidine is replaced with aspartate. Infection by FeLV-T requires FeLIX, a truncated envelope protein encoded by an endogenous FeLV, for transactivation of infectivity and Pit1 for binding FeLIX. Although Pit1 is present in most tissues in cats, the expression of FeLIX is limited to certain cells in lymphoid organs. Therefore, the host cell range of FeLV-T was thought to be restricted to cells expressing FeLIX. However, because FeLIX is a soluble factor and is expressed constitutively in lymphoid organs, we presumed it to be present in blood and evaluated its activities in sera of various mammalian species using a pseudotype assay. We demonstrated that cat serum has FeLIX activity at a functional level, suggesting that FeLIX is present in the blood and that FeLV-T may be able to infect cells expressing Pit1 regardless of the expression of FeLIX in vivo. In addition, FeLIX activities in sera were detected only in domestic cats and not in other feline species tested. To our knowledge, this is the first report to prove that a large amount of truncated envelope protein of endogenous retrovirus is circulating in the blood to facilitate the infection of a pathogenic exogenous retrovirus. © 2015 The Authors. Source

Discover hidden collaborations