Urotrichus Research Articles

Genotoxic Assessment of Small Mammals at an Illegal Dumpsite at the Aomori-Iwate Prefectural Boundary

In 2003, we examined the chromosomes of grass voles at an illegal dumpsite at the Aomori-lwate prefectural boundary. In subsequent years, from 2003-2006, we surveyed the chromosomes of four species of small mammals, namely, the Japanese grass vole (Microtus montebelli), the large Japanese field mouse (Apodemus speciosus), the small Japanese field mouse (A. argenteus), and the greater Japanese shrew mole (Urotrichus talpoides). Each annual survey revealed, both on a yearly basis and during the entire period in question, that the frequencies of breaks and gaps in chromosomes of M. montebelli were significantly higher at the dumpsite than on the outskirts and in controls, suggesting that grass voles at the dumpsite have been subject to continuous genotoxic effects since the establishment of the dumpsite. We also ascertained that grass voles are much more susceptible to chromosomal damage than field mice and shrew moles, which had very low levels of chromosomal aberrations at the dumpsite, on the outskirts of the dumpsite, and in controls. Our four-year survey revealed two variants of M. montebelli from the dumpsite with M6 fission (2n=31), two variants of A. speciosus from the outskirts with XO monosomy (2n=47, XO), and a variant of A. speciosus from the dumpsite with situs inversus. Our analysis confirms our previously proposed hypothesis that M. montebelli might be useful as an indicator species for genotoxic assessment of below-ground pollution by industrial waste at illegal dumpsites.

Observations on Food Obtaining Behavior of the Japanese Shrew-mole, Urotrichus talpoides

Observations on Food Obtaining Behavior of the Japanese Shrew-mole, Urotrichus talpoides

Karyotype Evolution of Shrew Moles (Soricomorpha: Talpidae)

The Chinese long-tailed mole (Scaptonyx fusicaudus) closely resembles American (Neurotrichus gibbsii) and Japanese (Dymecodon pilirostris and Urotrichus talpoides) shrew moles in size, appearance, and ecological habits, yet it has traditionally been classified either together with (viz subfamily Urotrichinae) or separately (tribe Scaptonychini) from the latter genera (tribe Urotrichini sensu lato). We explored the merit of these competing hypotheses by comparing the differentially stained karyotypes of S. fusicaudus and N. gibbsii with those previously reported for both Japanese taxa. With few exceptions, diploid chromosome number (2n = 34), fundamental autosomal number (FNa = 64), relative size, and G-banding pattern of S. fusicaudus were indistinguishable from those of D. pilirostris and U. talpoides. In fact, only chromosome 15 differed significantly between these species, being acrocentric in D. pilirostris, subtelocentric in U. talpoides, and metacentric in S. fusicaudus. This striking similarity is difficult to envisage except in light of a shared common ancestry, and is indicative of an exceptionally low rate of chromosomal evolution among these genera. Conversely, the karyotype of N. gibbsii deviates markedly in diploid chromosome and fundamental autosomal number (2n = 38 and FNa = 72, respectively), morphology, and G-banding pattern from those of Scaptonyx and the Japanese shrew moles. These differences cannot be explained by simple chromosomal rearrangements, and suggest that rapid chromosomal reorganization occurred in the karyotype evolution of this species, possibly due to founder or bottleneck events.

Molecular phylogeny of a newfound hantavirus in the Japanese shrew mole ( Urotrichus talpoides )

Recent molecular evidence of genetically distinct hantaviruses in shrews, captured in widely separated geographical regions, corroborates decades-old reports of hantavirus antigens in shrew tissues. Apart from challenging the conventional view that rodents are the principal reservoir hosts, the recently identified soricid-borne hantaviruses raise the possibility that other soricomorphs, notably talpids, similarly harbor hantaviruses. In analyzing RNA extracts from lung tissues of the Japanese shrew mole (Urotrichus talpoides), captured in Japan between February and April 2008, a hantavirus genome, designated Asama virus (ASAV), was detected by RT-PCR. Pairwise alignment and comparison of the S-, M-, and L-segment nucleotide and amino acid sequences indicated that ASAV was genetically more similar to hantaviruses harbored by shrews than by rodents. However, the predicted secondary structure of the ASAV nucleocapsid protein was similar to that of rodent- and shrew-borne hantaviruses, exhibiting the same coiled-coil helix at the amino terminus. Phylogenetic analyses, using the maximum-likelihood method and other algorithms, consistently placed ASAV with recently identified soricine shrew-borne hantaviruses, suggesting a possible host-switching event in the distant past. The discovery of a mole-borne hantavirus enlarges our concepts about the complex evolutionary history of hantaviruses.

Size and Distribution of Home Ranges of the Japanese Shrew-mole Urotrichus talpoides

Size and Distribution of Home Ranges of the Japanese Shrew-mole Urotrichus talpoides

The evolution of female mole ovotestes evidences high plasticity of mammalian gonad development

Previous studies of the reproductive biology and genetics of European moles (Talpa spp.) showed that all females of these species have ovotestes (gonads with testicular and ovarian tissue) instead of normal ovaries, a unique specialization among mammals. Females are fertile as their ovarian tissue is fully functional. Testicular tissue is abnormal and sterile, but produces high levels of testosterone. This phenomenon also characterizes other talpid species from Europe and North America. To study the origin of this singular reproductive specialization, we examined the gonads of several female specimens belonging to two critical taxa. Although large Japanese moles (Mogera wogura) posses ovotestes, greater Japanese shrew moles (Urotrichus talpoides) are characterized by normal ovaries. The results fit parsimoniously with a recent phylogenetic study that places Urotrichus relatively basal in the talpid tree and separate from the American shrew mole. Parsimony reconstruction on alternative phylogenetic hypotheses clearly indicates that reversal(s) must have occurred and suggests that a relatively simple genetic mechanism must be associated with the evolution of female hermaphroditism in moles.

The Delayed Quinacrine Mustard Fluorescence from the C-blocks of Apodemus argenteus Is Due to the Introduction of Nicks into the DNA

"Delayed QM-fluorescence" refers to the unusual kinetics of fluorescence from most of the C-heterochromatic regions of the chromosomes of the small Japanese field mouse Apodemus argenteus. When stained with quinacrine mustard (QM-stained), these C-heterochromatic regions emit weak fluorescence immediately after exposure to blue light (BL); they emit bright fluorescence within a few minutes; and the intensity of the fluorescence gradually decreases after maximum fluorescence has been recorded. To elucidate the mechanism of this phenomenon, we used acridine orange staining (AO-staining) and a modified version of the in situ nick-translation method. Focusing on the large C-heterochromatic region (C-block) of the X chromosome, we noted that AO-stained C-blocks emitted greenish fluorescence, while QM-stained and BL-exposed (QM-BL-processed) C-blocks emitted reddish fluorescence upon AO-staining after removal of QM. These findings suggested that the C-block DNA of A. argenteus might undergo a structural change, such as strand breaks, during QM-BL processing. Application of the modified in situ nick-translation method revealed the generation of an appreciable number of nicks in the C-block DNA by QM-BL processing. No such nick formation was observed in the C-blocks of three other mammalian species: Apodemus peninsulae, Microtus montebelli, and Urotrichus talpoides. Our findings support the hypothesis that nick formation due to exposure to BL might play a primary role in inducing delayed QM-fluorescence in the C-blocks of A. argenteus. On the basis of the present and earlier findings, we propose a probable mechanism for delayed QM-fluorescence in A. argenteus chromosomes.

オオクチバス Micropterus salmoides に摂食されたヒミズ Urotrichus talpoides

オオクチバス Micropterus salmoides に摂食されたヒミズ Urotrichus talpoides

A comprehensive morphological analysis of talpid moles (Mammalia) phylogenetic relationships.

Some talpid moles show one of the most specialized suites of morphological characters seen among small mammals. Fossorial and more generalized shrew-looking moles inhabit both North America and Eurasia but these land masses share none of the same genera. One of the central questions of mole evolution has been that of how many times specialized fossorial habits evolved. We investigated the origin of mole characters with a maximum parsimony analysis of 157 characters, mostly craniodental and postcranial, of representatives of all 17 living mole genera and three shrews and one hedgehog as outgroups. The result was one most-parsimonious tree and its most novel aspect was the position of a Japanese shrew mole clade (Urotrichus, Dymecodon), which branched off after Uropsilus and was not closely related to the American shrew mole (Neurotrichus). The desmans (Galemys and Desmana) were the next clade in the tree, followed by Neurotrichus. We confirmed the monophyly of the Eurasian fossorial mole clade Talpini (Euroscaptor, Parascaptor, Mogera, Scaptochirus and Talpa). Condylura, the star-nosed mole from North America, was sister group to a clade consisting of the Talpini plus Scaptonyx and the Scalopini (Scalopus, Scapanus, Parascalops, and Scapanulus). Based on our results and on the assumption that moles originated in Eurasia, it is most parsimonious to infer one migration from Eurasia to North America and two back-migrations to Eurasia. It is ambiguous if Talpini and Scalopini evolved their full fossorial habits independently or not.

An evolutionary view on the Japanese talpids based on nucleotide sequences

Japanese talpid moles exhibit a remarkable degree of species richness and geographic complexity, and as such, have attracted much research interest by morphologists, cytogeneticists, and molecular phylogeneticists. However, a consensus hypothesis pertaining to the evolutionary history and biogeography of this group remains elusive. Recent phylogenetic studies utilizing nucleotide sequences have provided reasonably consistent branching patterns for Japanese talpids, but have generally suffered from a lack of closely related South-East Asian species for sound biogeographic interpretations. As an initial step in achieving this goal, we constructed phylogenetic trees using publicly accessible mitochondrial and nuclear sequences from seven Japanese taxa, and those of related insular and continental species for which nucleotide data is available. The resultant trees support the view that four lineages (Euroscaptor mizura, Mogera tokuade species group [M. tokudae and M. etigo], M. imaizumii, and M. wogura) migrated separately, and in this order, from the continental Asian mainland to Japan. The close relationship of M. tokudae and M. etigo suggests these lineages diverged recently through a vicariant event between Sado Island and Echigo plain. The origin of the two endemic lineages of Japanese shrew-moles, Urotrichus talpoides and Dymecodon pilirostris, remains ambiguous. Further analyses on intra-species diversity are necessary to fully solve the evolutionary histories of Japanese moles and shrew-moles.

Karyotypic evolution and organization of the highly repetitive DNA sequences in the Japanese shrew-moles, Dymecodon pilirostris and Urotrichus talpoides

The karyological relationship and organization of highly repetitive DNA sequences in Japanese shrew-moles were studied by zoo-blot hybridization and fluorescence in situ hybridization (FISH). When the genomic DNA of the eastern race of Urotrichus talpoides was digested with PstI, three fragments of highly repetitive DNA sequences, approximately 0.7, 0.9, and 1.4 kb in length, were observed as distinct bands. The results of FISH in the eastern race of U. talpoides using these three fragments separately as probes showed that the 0.7-kb PstI fragment was distributed in the centromeric regions of most chromosomes, and that the 0.9- and 1.4-kb fragments were predominantly located in the C-heterochromatin region of chromosome 13p. Although the western race of U. talpoides also had three PstI fragments, 0.9- and 1.4-kb PstI fragments were more ambiguous than those of the eastern race. The PstI- digested genomic DNA in Dymecodonpilirostris produced only a faint 0.9-kb band, and its signal patterns obtained by zoo-blot hybridization were clearly different from those of U. talpoides. The 0.7-kb fragment of U. talpoides hybridized strongly with the 0.9-kb fragment of D. pilirostris. In a FISH analysis, the 0.9-kb fragment of D. pilirostris hybridized with highly repetitive DNA in the centromeric regions of most chromosomes from both D. pilirostris and U. talpoides. Zoo-blot hybridization and FISH analyses suggest that the 0.9- and 1.4-kb PstI fragments were generated specifically in the genome of U. talpoides after the common ancestor differentiated into two extant shrew-mole species. A difference in the length of the centromeric elements between U. talpoides and D. pilirostris might be observed due to certain modifications of the repeating unit.

Mitochondrial phylogeny of hedgehogs and monophyly of Eulipotyphla

We sequenced the complete mitochondrial (mt) genomes of three insectivores: the long-eared hedgehog Hemiechinus auritus, the Japanese mole Mogera wogura, and the greater Japanese shrew-mole Urotrichus talpoides. These mtDNA data together with other previously sequenced mtDNAs were analyzed using a maximum likelihood method to infer their phylogenetic relationships among eutherians. Previous mitochondrial protein analyses used a simple model that did not consider site-heterogeneity, and Erinaceoidea (hedgehogs and moonrats) was placed at the basal eutherian position that is separated from Soricoidea (shrews) and Talpoidea (moles), suggesting the exclusion of the Erinaceoidea–Eulipotyphla tree. By including the new mtDNA sequences and introducing site-heterogeneity into the model, the Erinaceoidea–Eulipotyphla tree emerges as the best tree or as a tree with a log-likelihood score indistinguishable from that of the best tree. However, this conclusion depends on species sampling in Erinaceoidea, demonstrating the importance of both species sampling and use of an appropriate substitution model when inferring phylogenetic relationships.

Molecular phylogenetic relationships of moles, shrew moles, and desmans from the new and old worlds

A rich variety of anatomical and physiological specializations has enabled members of the family Talpidae (moles, shrew moles, and desmans) to exploit a diverse range of habitats: terrestrial, semi-aquatic, aquatic/fossorial, semi-fossorial, and fossorial. While numerous morphological and biochemical studies pertaining to the origin and radiation of the Talpidae have been completed, phylogenetic hypotheses remain controversial. To address this shortcoming we sequenced the mitochondrial DNA cytochrome b gene (1140 bp) from 29 individuals spanning 12 talpid species. Phylogenetic trees incorporating 12 New and Old World genera (18 species; all 3 extant subfamilies) were then constructed using NJ, MP, ML, and NJ–ML (NJ with ML parameters) methods. Our results provide molecular support for a mononphyletic Talpidae, and suggest that the 12 genera are clustered into seven major clades; (1) Asiatic shrew-like moles ( Uropsilus), (2) North American aquatic/fossorial moles ( Condylura), (3) North American fossorial moles ( Parascalops, Scalopus, and Scapanus), (4) North American semi-fossorial shrew moles ( Neurotrichus), (5) Japanese semi-fossorial shrew moles ( Dymecodon and Urotrichus), (6) European semi-aquatic desmans ( Desmana), and (7) Eurasian fossorial moles ( Euroscaptor, Mogera, and Talpa). None of these groupings comprised mole species from both continents. In fact, North American moles and shrew moles do not appear to have specific affinities with Asian moles and shrew moles, respectively. Although low bootstrap support was generally found for evolutionary nodes uniting the major talpid clades, all gene trees constructed identified fossorial North American and Eurasian mole lineages as nonmonophyletic groups, suggesting subterranean specializations arose independently at least twice during the evolution of the Talpidae. Additionally, our data set provides molecular support for a basal divergence and long independent history of Uropsilus from the main talpid line, and refutes the traditional taxonomic status and secondarily basal phylogenetic placement of the subfamily Desmaninae within the Talpidae.

Geographical Variations in Chromosomes of the Greater Japanese Shrew-Mole, Urotrichus talpoides (Mammalia: Insectivora)

Karyotypes of the greater Japanese shrew-mole, Urotrichus talpoides (Talpidae), collected from 57 localities in Japan were studied by conventional, G- and C-band staining techniques to elucidate geographical chromosomal variations, the mechanism of changes in chromosomes, and the distribution patterns of karyotypic races. Shrew-mole samples examined could be divided geographically into two slightly divergent chromosomal forms designated as the western and eastern races. These two karyotypic races had the same diploid number (34) and fundamental number (64), but they had autosomes with different makeups. A comparison of conventional karyotypes showed a distinct intraspecific variation in shape of autosomal pair no. 14 which was classified as subtelocentric in the western race and as metacentric in the eastern race. G- and C-banding analyses revealed that karyotypic variation found in no. 14 pair was involved in pericentric inversion and quantitative changes in constitutive heterochromatin. Intraspecific and geographical variation in chromosomes caused by such karyological events is rare and unique among members of the family Talpidae examined so far. Furthermore, our results demonstrated that the clear boundary between the two parapatric karyotypic races was actually located along the Kurobe-Fuji line in the central part of Honshu, but not along the Owari-Tsuruga isthmian line previously postulated by Tsuchiya (1987, 1988). Zoogeographical implications of the boundary of parapatric distribution in U. talpoides are also discussed.

Distribution of Lectin Bindings in the Testes of the Greater Japanese Shrew Mole, Urotrichus talpoides.

The binding patterns of 20 lectins in the testes of the greater Japanese shrew mole (Urotrichus talpoides) were investigated by light microscopy. Eleven lectins (WGA, sWGA, LEL, STL, Jacalin, PSA, LCA, BPA, Con-A, WGA and PHA-E) exhibited a positive reaction in the cytoplasm and acrosomal region of spermatids and in the cytoplasm of Sertoli cells. LEL, BSL-I, DSA, sWGA, BSL-I and PHA-L were intensely positive in the cytoplasm of Leydig cells. The binding patterns in the acrosomal region of spermatids were divided into three types. For LEL, ECL and STL, the reaction was detected in the acrosomal regions from Golgi to cap phase spermatids and disappeared in acrosome and maturation phase spermatids. For SBA, VVL, ECL and DSL, the reaction was detected in the acrosomal region from Golgi to acrosome phase spermatids. No reaction was recognized in the acrosome of maturation phase spermatids. In DBA and Jacalin, the cytoplasm of maturation phase spermatids was positive although no reaction was detected in the acrosomal region of all spermatids. sWGA, BPA and LEL exhibited a strong reaction in the plasma membrane of zygotene spermatocytes at stages X and XI. BSL-II revealed a strong reaction in the cytoplasm of spermatogonia.

神奈川, 山梨, 静岡, 長野各県および東京都に生息する野生動物の寄生虫調査

From 1997 to 1999, epidemiological surveys of helminths in such wild mammals as foxes and rodents were conducted in Kanagawa, Yamanashi, Shizuoka, and Nagano Prefectures and in Tokyo. Each infected fox harbored two or more of the following helminth species: six species of nematodes (Taxocara canis, Trichuris vulpis, Anclystoma kushimaense, Arthrostoma miyazakiense, Strongyloides planiceps, and Molineus patens); two species of trematodes (Metagonimus takahashii and Concinnum ten); and one species of cestode (Taenia pisiformis). In total, nine different helminths were detected in 25 (78.1%) of 32 animals examined. The crysticerci T. taeniaeformis and T. crassiceps were found in Rattus rattus and in Apodemus speciosus. The pleroceroide of Spirometra erinaceieuropaei was detected for the first time in Urotrichus talpoides, heretofore never considered a host. No Echinococcus adults or larvae, however, were detected in the animals examined.

A Close Relationship of Chiroptera with Eulipotyphla (Core Insectivora) Suggested by Four Mitochondrial Genes

Abstract We sequenced the mitochondrial cytochrome b, 12S rRNA and 16S rRNA genes from three insectivoran species (Japanese mole, shrew mole and musk shrew) and one chiropteran species(Japanese pipistrelles) and the cytochrome c oxidase subunit II (COII) gene from a chiropteran species. The phylogenetic relationship of core Insectivora or Eulipotyphla among major Eutherian orders was examined for these genes. A total evaluation of the maximum likelihood analyses of the four genes suggests that Chiroptera is the closest to Eulipotyphla among 4 eutherian groups (Primates, Eulipotyphla, Fereuungulata, Rodentia).

Reconsideration of the Karyological Relationship between Two Japanese Species of Shrew-moles, Dymecodon pilirostris and Urotrichus talpoides

Abstract Details of the karyological relationship between the lesser Japanese shrew-mole Dymecodon pilirostris (2n = 34) and the greater Japanese shrew-mole Urotrichus talpoides (2n = 34) were examined by five differential-staining techniques, namely, G-, C-, NOR-, Q- and CMA-banding. Staining revealed that thirteen autosomal pairs and the sex chromosomes of the two species exhibited strong homology in terms of banding patterns. The remaining three autosomal pairs, nos.13, 14 and 15, exhibited distinct interspecific differences both in banding patterns and in the morphology of the respective chromosomes. These interspecific differences can be explained by the presence or absence of an unusual (G-, C-, NOR- and Q-band-negative, but CMA-band-positive) region of chromatin, by the pericentric inversion inv (14) (p13q31), and by duplication of C-heterochromatin, respectively. It has been suggested that the unusual chromatin found in U. talpoides might contain highly repetitive GC-rich sequences, even though it...

Helminth fauna of carnivores distributed in north-western Tohoku, Japan, with special reference to Mesocestoides paucitesticulus and Brachylaima tokudai.

In the winter of 1998-1999, we collected parasitological data from 54 wild carnivores in the north-western part of Tohoku region, Japan. These consisted of 38 martens (Martes melampus melampus), 14 raccoon dogs (Nyctereutes procyonoides viverrinus) and 2 foxes (Vulpes vulpes japonica). Collected helminth parasites were 11 nematode, 10 trematode, 3 cestode, and a single acanthocephalan species, including 5 hitherto unknown species for this research area or the mainland of Japan (Honshu). Mesocestoides paucitesticulus was for the first time recorded from martens as well as from carnivores distributed in Honshu. Brachylaima tokudai originally recorded from Urotrichus talpoides in the central part of Honshu was for the first time found from a raccoon dog.

Crown structure of the maxillary molars in the Japanese shrew mole, Urotrichus talpoides (Insectivora, Talpidae).

The maxillary first and second molars (M1 and M2) in the Japanese shrew mole, Urotrichus talpoides, were investigated using an odontometrical approach. The mesiodistal crown diameter was larger in M1 than in M2, while the buccolingual diameter of M1 was nearly equal to that of M2. M2 was more compressed mesiodistally than M1. M1 had a large distal triangle on the stylar shelf. The mesial triangle of M2 was slightly larger than the distal triangle. Despite being smaller than M1, M2 was less variable than M1 in terms of size. The distal triangle of M1 and the mesial triangle of M2 were well developed, and thus this area, which corresponds to the inflection point of the maxillary dental arch, was most likely the center of an occlusal function.