Tokyo, Japan
Tokyo, Japan
Time filter
Source Type

Sakuma Y.,Hokkaido University | Ranorosoa M.C.,Parc Botanique et Zoologique de Tsimbazaza | Kinoshita G.,Hokkaido University | Shimoji H.,Hokkaido University | And 6 more authors.
Mammal Study | Year: 2016

Variability in the coat color of the house mouse, Mus musculus, provides an opportunity to study the evolution of phenotypes in this species. Here we associated genetic variations with coat color in seven mice from Madagascar that had identical M. m. gentilulus mitochondrial DNA sequences. The entire coding region of the 948-base pair (bp) coat-color-related gene, Mc1r, was shown to have no nonsynonymous changes. However, analyses of the two exon-1 promoter regions-termed 1A (317 bp) and 1B (499 bp)-from a second gene, Asip, which is also involved in the evolution of coat color, revealed two distinct haplotypes in each region. Associations between Asip promoter regions and dorsal color were ambiguous; however, two ventral color types-light and dark gray-were associated with the haplotypes of 1A, as determined by clustering analysis. Notably, the haplotype of the light gray animals was identical to the Asip Aw allele that is associated with white bellies. © The Mammal Society of Japan.

Ohdachi S.D.,Hokkaido University | Kinoshita G.,Kyoto University | Oda S.-I.,Yomogidai 3 518 | Motokawa M.,Kyoto University | And 16 more authors.
Mammal Study | Year: 2016

A phylogenetic tree was reconstructed based on the mitochondrial cytochrome b gene nucleotide sequences of 169 individuals of house shrews (Suncus murinus and S. montanus) from 44 localities in East Asia, Southeast Asia, West Asia, and islands in the western Indian Ocean. Shrews from China (Zhejiang), Japan (Okinawa), Vietnam, and Indonesia (Java) formed a monophyletic group with less genetic variation. Therefore, the shrews of these regions appeared to have originated from one or a few localities. Contrary to this, shrews from Sri Lanka, Myanmar, and Pakistan consisted of several haplogroups. This finding suggests immigration movements to these areas. Fascinating findings were also obtained concerning the islands in the western Indian Ocean. First, shrews on Zanzibar Island (Tanzania) had almost the same haplotype as those in southwestern Iran. Therefore, the house shrew in Zanzibar may have immigrated from Iran (or vice versa). Second, shrews from Madagascar and Grande Comore Island shared the same haplotype, whereas the shrews on Réunion Island were clearly different from those of Madagascar and Comoros. Thus, there appears to have been several immigration routes to the islands of the western Indian Ocean. © The Mammal Society of Japan.

Suzuki H.,Hokkaido University | Nunome M.,Hokkaido University | Kinoshita G.,Hokkaido University | Aplin K.P.,Smithsonian Institution | And 10 more authors.
Heredity | Year: 2013

We examined the sequence variation of mitochondrial DNA control region and cytochrome b gene of the house mouse (Mus musculus sensu lato) drawn from ca. 200 localities, with 286 new samples drawn primarily from previously unsampled portions of their Eurasian distribution and with the objective of further clarifying evolutionary episodes of this species before and after the onset of human-mediated long-distance dispersals. Phylogenetic analysis of the expanded data detected five equally distinct clades, with geographic ranges of northern Eurasia (musculus, MUS), India and Southeast Asia (castaneus, CAS), Nepal (unspecified, NEP), western Europe (domesticus, DOM) and Yemen (gentilulus). Our results confirm previous suggestions of Southwestern Asia as the likely place of origin of M. musculus and the region of Iran, Afghanistan, Pakistan, and northern India, specifically as the ancestral homeland of CAS. The divergence of the subspecies lineages and of internal sublineage differentiation within CAS were estimated to be 0.37-0.47 and 0.14-0.23 million years ago (mya), respectively, assuming a split of M. musculus and Mus spretus at 1.7 mya. Of the four CAS sublineages detected, only one extends to eastern parts of India, Southeast Asia, Indonesia, Philippines, South China, Northeast China, Primorye, Sakhalin and Japan, implying a dramatic range expansion of CAS out of its homeland during an evolutionary short time, perhaps associated with the spread of agricultural practices. Multiple and non-coincident eastward dispersal events of MUS sublineages to distant geographic areas, such as northern China, Russia and Korea, are inferred, with the possibility of several different routes. © 2013 Macmillan Publishers Limited.

Yasuda S.P.,Hokkaido University | Yasuda S.P.,Japanese Dormice Preservation and Research Group | Iwabuchi M.,Japanese Dormice Preservation and Research Group | Iwabuchi M.,University of Miyazaki | And 9 more authors.
Zoological Science | Year: 2012

We previously revealed the presence of six genetically distinct matrilineal populations of the Japanese dormouse Glirulus japonicus in the distribution range of Honshu, Shikoku, and Kyushu islands. In this study, we extended this analysis using mitochondrial cytochrome b gene sequences (n = 96) and Y-chromosome-specific SRY gene sequences (n = 22) from individuals collected from Honshu, Shikoku, Kyushu, and Oki Dogo I. The cytochrome b sequence data allowed us to define precise geographic ranges of the six previously known and three newly found distinct matrilineal lineages: northeastern Honshu (I), east-central Honshu (II), west-central Honshu and the Kii Peninsula (III), the western part of Honshu (IV), Shikoku (V), westernmost Honshu and Kyushu (VI), the northern part of central Honshu (VII), the southern part of central Honshu (VIII), and Oki Dogo I. (IX). Our inference of geographic borders suggests that regions of lower and higher altitudes in the mountain systems played important roles in driving the hosting and separation of lineages, respectively. Six matrilineal lineages (I, II, V, VI, VIII, and XI) were shown to possess their own SRY haplotypes, while lineages III and IV shared one haplotype. These data together with our previous observation of nuclear ribosomal RNA gene variation indicate advanced populational subdivision in this species. It is thus evident that each of the populations, including those living at high latitudes and in limited geographic spaces, have survived for several million years. A specific ability to tolerate cold may have permitted G. japonicus to preserve anciently diverged lineages in each locality. © 2012 Zoological Society of Japan.

Kirihara T.,Hokkaido University | Shinohara A.,University of Miyazaki | Tsuchiya K.,App TOKYO Co. | Harada M.,Osaka City University | And 2 more authors.
Zoological Science | Year: 2013

We assessed dispersal and vicariant events in four species of Japanese moles in the genera Mogera and Euroscaptor to better understand the factors shaping intra- and interspecific differentiation in Japanese moles. We used the combined viewpoints of molecular phylogeny and historical geology using nucleotide sequences of mitochondrial (cytochrome b; Cytb) and nuclear (A2ab, Bmp4, Tcf25, vWf) genes. The divergence times estimated from the molecular data were verified with available geological data on the chronology of fluctuations in sea level in the Korea Strait, assuming sequential migration and speciation events. This produced possible migration times of 5.6, 3.5, 2.4, and 1.3 million years ago for four species of Japanese moles, Euroscaptor mizura, Mogera tokudae, M. imaizumii, and M. wogura, respectively. For the western Japanese mole M. wogura, Cytb sequences revealed four major phylogroups with strong geographic affinities in southwestern Central Honshu (I), western Honshu/Shikoku (II), Kyushu/westernmost Honshu (III), and Korea/Russian Primorye (IV). The nuclear gene sequences supported the distinctiveness of phylogroups I and IV, indicating long, independent evolutionary histories. In contrast, phylogroups II and III were merged into a single geographic group based on the nuclear gene data. Intraspecific divergences in M. imaizumii and M. tokudae were rather apparent in Cytb but not in nuclear gene sequences. The results suggest that repeated dispersal events have occurred between the Asian continent and the Japanese Islands, and intensive vicariant events associated with abiotic and biotic factors have created higher levels of species and genetic diversities in moles occurring on the Japanese Islands. © 2013 Zoological Society of Japan.

PubMed | App TOKYO Co.
Type: Journal Article | Journal: Meat science | Year: 2011

Three troponin components were isolated from bovine skeletal muscle, and their molecular weights and amino acid composition were studied. Crude troponin prepared from bovine muscle was purified by DEAE-Toyopearl chromatography. The purified troponin was dissociated in the order of tropopins C, I and T by CM-Toyopearl chromatography in the presence of 6 M urea. The molecular weights of troponins C, I and T were 19,500, 23,300 and 40,400, respectively, as determined with SDS-PAGE. The separation of troponin into three components was also achieved using reverse-phase HPLC; however, the elution order of troponins T and C was contrary to that of the cation-exchange chromatography described above. In this study, the amino acid composition of the three troponin components from bovine skeletal muscle was first determined. The amino acid composition of the three troponin components among bovine, rabbit and chicken skeletal muscles showed stronger similarity than that between bovine skeletal and cardiac muscle with a different muscle type. We considered that this method of troponin preparation from bovine muscle must be a very useful technique for investigating the changes in troponin components, especially troponin T, during ageing of beef.

PubMed | App TOKYO Co.
Type: Journal Article | Journal: Meat science | Year: 2011

The most predominant component appearing on SDS-PAGE of myofibrils prepared from bovine m. vastus intermedius (VI) during ageing for 31 days post mortem at 0-2 C was a component with a molecular weight of 32 kDa (SDS-32 kDa). In this study, the origin of the SDS-32 kDa component, which was thought to correspond to the 30 kDa component already known, was investigated. On the SDS-PAGE of the crude troponins, both troponin T and the 34 kDa component were gradually degraded during ageing and then troponin T disappeared at 24 days post mortem, while the concentration of the 32 kDa component showed a tendency to increase during ageing. The 32 kDa component was prepared from troponin of bovine VI muscle stored for 17 days post mortem using CM-Toyopearl chromatography, and named the native 32 kDa component. Its mobility on SDS-PAGE agreed with that of the SDS-32 kDa component. The SDS-32, native 32 and 34 kDa components were recognized by the polyclonal anti-troponin T antibody, and furthermore, the patterns of amino acid composition of both the native 32 and 34 kDa components were very similar to troponin T. Thus, it was considered that these two components would be polypeptides from the degradation of troponin T. We concluded that the SDS-32 kDa component must be derived from the degraded poly-peptides of troponin T. However, it still remains a possibility that some degradation products from other myofibrillar proteins are included in the SDS-32 kDa component. Therefore, further studies about the identity of this component will be required.

Nakahara K.,Osaka University | Mitsui C.,Osaka University | Okamoto T.,Osaka University | Yamagishi M.,Osaka University | And 5 more authors.
Chemistry Letters | Year: 2013

We focus on aggregated structures and charge-transporting properties in semiconductor assemblies of a new-type twisted π-conjugated molecule, dinaphtho[2,1-b:1′,2′-d]furan (DNF-U). Single crystals were successfully grown by physical vapor transport to form a two-dimensional herringbone packing structure, which is advantageous for intermolecular charge transport. Based on the packing structure, relatively large transfer integrals were theoretically calculated to be 20 and 57 meV for C-H π and π π direction, respectively. The single-crystal field-effect transistors exhibited notable hole mobility of up to 1.0 cm2V-1 s-11. © 2013 The Chemical Society of Japan.

PubMed | App TOKYO Co., Nagoya University and Hokkaido University
Type: | Journal: Scientific reports | Year: 2015

Hybrid sterility plays an important role in the maintenance of species identity and promotion of speciation. Male interspecific hybrids from crosses between Campbells dwarf hamster (Phodopus campbelli) and the Djungarian hamster (P. sungorus) exhibit sterility with abnormal spermatogenesis. However, the meiotic phenotype of these hybrids has not been well described. In the present work, we observed the accumulation of spermatocytes and apoptosis of spermatocyte-like cells in the testes of hybrids between P. campbelli females and P. sungorus males. In hybrid spermatocytes, a high frequency of asynapsis of X and Y chromosomes during the pachytene-like stage and dissociation of these chromosomes during metaphase I (MI) was observed. No autosomal univalency was observed during pachytene-like and MI stages in the hybrids; however, a low frequency of synapsis between autosomes and X or Y chromosomes, interlocking and partial synapsis between autosomal pairs, and -H2AFX staining in autosomal chromatin was observed during the pachytene-like stage. Degenerated MI-like nuclei were frequently observed in the hybrids. Most of the spermatozoa in hybrid epididymides exhibited head malformation. These results indicate that the pairing of X and Y chromosomes is more adversely affected than that of autosomes in Phodopus hybrids.

Loading App TOKYO Co. collaborators
Loading App TOKYO Co. collaborators