Search

Additional file 11:Summary of the genes sequenced for the phylogenetic reconstruction. List of the genes and their accession numbers which were used for the phylogenetic analysis. (DOC 39 KB)

Additional file 5:Distribution of the size of indels. We identified 284,007 insertions (positive values) and 345,249 deletions (negative values). (PDF 29 KB)

Additional file 7:GO terms which were over-represented in nsSNP-containing genes. (DOC 42 KB)

Additional file of Whole-genome resequencing shows numerous genes with nonsynonymous SNPs in the Japanese native cattle Kuchinoshima-Ushi

Additional file 10:List of species examined in this study. (DOC 48 KB)

Additional file 4:SNP distribution on each chromosome. SNP density (SNPs per 1 kbp) is plotted by physical position. Relative length of the chromosomes was correlated with the length of each chromosome without repeat regions. (PDF 149 KB)

Additional file 9:The number of SNPs and indels with various filters. Detected SNPs and indels were filtered with additional filters and the number of homozygous and heterozygous SNPs and indels was compared. Parameters for the filters were (1) Depth: the number of reads mapped to the SNP sites, (2) SNPs: the number of reads calling SNP at the SNP site, and (3) Mutation: the cutoff value of percent aligned reads calling the SNP per total mapped reads at the SNP sites. Cut off value was 30% in all filters. In the table, "%" means the reduced percentage of the number of SNPs/indels compared with basic parameters (i.e., Depth≥ 3, SNPs≥ 2, and Mutation≥ 30). (PDF 63 KB)

Additional file 3:The number of identified SNPs and indels for each chromosome. SNPs are shown in the blue columns, and indels are shown in the red columns. Length of chromosomes is indicated by the green line. (PDF 72 KB)

Additional file 1:Reads for all chromosomes of repeat masked and unmasked genome assembly. In each chromosome, left columns show the reads mapped to the assembly without repeat masking and right columns show those to the repeat-masked assembly. Among the reads that were mapped to the reference genome sequence, most were mapped in pairs (blue column in each chromosome). However, in some read pairs, only one was mapped (red column). Additionally, some read pairs were mapped, but the distances or directions were not adequate (green columns). Length of the chromosomes is shown in the yellow line. High number of reads mapped to BTA13 of the assembly without repeat masking (left column) was removed in the repeat-masked assembly (right column). (PDF 78 KB)

A 3, 3'-diaminobenzidine (DAB)-based method was used to detect the localization of endogenous peroxidase activity in Indian rhinoceros (Rhinoceros unicornis) parotid gland acinar cells. The tissue had previously been resin-embedded in gelatin capsules for routine electron microscopic observations and thus pre-incubation for endogenous peroxidase analysis was not possible. We attempted to demonstrate the relationship between secretory granules (SGs) in resin ultrathin sections of Indian rhinoceros parotid gland acinar cells and endogenous peroxidase activity. A JEM 1400 Plus scanning transmission electron microscope (STEM) was used to conduct energy dispersive X-ray spectroscopy (EDS) analysis of the presence of nitrogen generated by the DAB reaction in bipartite structural SG consisting of a dense body (or core). The mapping patterns of nitrogen were restricted to the dense body. We observed nitrogen localized in the rough endoplasmic reticulum (ER), nuclear envelope (NE) and several components of the Golgi apparatus (G) of rhinoceros parotid gland acinar cells participating in the synthetic pathway of secretory proteins. Moreover, we established a nitrogen-detection method by EDS analysis of rhinoceros parotid gland. The reliability of the method was validated by comparison of the test group (peroxidase detection in ultrathin resin sections) and the control group (ordinary peroxidase detection in semi-thin sections following glutaraldehyde pre-fixation) of rat submandibular gland. The same mapping patterns of nitrogen were detected by DAB reaction in the SG, ER, NE and G in these two groups. Hence, EDS-STEM approaches for endogenous peroxidase post-incubation analysis will prove useful for advanced cytochemical analysis for the identification of any other resin sections.

Background 3,3'-diaminobenzidine tetrazolium (DAB)-based methods have been developed to detect the localization of peroxidase (PO) activity. Histochemically, endogenous PO activity has been localized to acini of human and rodent salivary glands. This suggests that the enzyme may be used as a convenient marker of differentiated acinar cells to study factors that influence the development of the rat submandibular gland. We also investigated endogenous PO localization differences between rodent and insectivora ( Suncus murinus) major salivary glands by light and electron microscopy. Moreover, ectopic sublingual gland-like tissue was found in the resin-embedded semi-thin sections of DAB-reacted hamster submandibular gland by confocal laser scanning microscopy. Highlight Reflectance-mode confocal laser scanning microscopy was employed to visualize sites of PO activity in ectopic sublingual gland-like tissue of the hamster submandibular gland. Conclusion The technique proposed here may result in novel applications for DAB-based histochemistry.

Background and objective Although named because of its sucrose hydrolytic activity, this mucosal enzyme plays a leading role in starch digestion because of its maltase and glucoamylase activities. Sucrase-deficient mutant shrews, Suncus murinus, were used as a model to investigate starch digestion in patients with congenital sucrase-isomaltase deficiency.Starch digestion is much more complex than sucrose digestion. Six enzyme activities, 2 α-amylases (Amy), and 4 mucosal α-glucosidases (maltases), including maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si) subunit activities, are needed to digest starch to absorbable free glucose. Amy breaks down insoluble starch to soluble dextrins; mucosal Mgam and Si can either directly digest starch to glucose or convert the post-α-amylolytic dextrins to glucose. Starch digestion is reduced because of sucrase deficiency and oral glucoamylase enzyme supplement can correct the starch maldigestion. The aim of the present study was to measure glucogenesis in suc/suc shrews after feeding of starch and improvement of glucogenesis by oral glucoamylase supplements. Methods Sucrase mutant (suc/suc) and heterozygous (+/suc) shrews were fed with C-enriched starch diets. Glucogenesis derived from starch was measured as blood C-glucose enrichment and oral recombinant C-terminal Mgam glucoamylase (M20) was supplemented to improve starch digestion. Results After feedings, suc/suc and +/suc shrews had different starch digestions as shown by blood glucose enrichment and the suc/suc had lower total glucose concentrations. Oral supplements of glucoamylase increased suc/suc total blood glucose and quantitative starch digestion to glucose. Conclusions Sucrase deficiency, in this model of congenital sucrase-isomaltase deficiency, reduces blood glucose response to starch feeding. Supplementing the diet with oral recombinant glucoamylase significantly improved starch digestion in the sucrase-deficient shrew.

Several regions of the brain and spinal cord control male reproductive function. We previously demonstrated that the gastrin-releasing peptide (GRP) system, located in the lumbosacral spinal cord of rats, controls spinal centers to promote penile reflexes during male copulatory behavior. However, little information exists on the male-specific spinal GRP system in animals other than rats. The objective of this study was to examine the functional generality of the spinal GRP system in mammals using the Asian house musk shrew (Suncus murinus; suncus named as the laboratory strain), a specialized placental mammal model. Mice are also used for a representative model of small laboratory animals. We first isolated complementary DNA encoding GRP in suncus. Phylogenetic analysis revealed that suncus preproGRP was clustered to an independent branch. Reverse transcription-PCR showed that GRP and its receptor mRNAs were both expressed in the lumbar spinal cord of suncus and mice. Immunohistochemistry for GRP demonstrated that the sexually dimorphic GRP system and male-specific expression/distribution patterns of GRP in the lumbosacral spinal cord in suncus are similar to those of mice. In suncus, we further found that most GRP-expressing neurons in males also express androgen receptors, suggesting that this male-dominant system in suncus is also androgen-dependent. Taken together, these results indicate that the sexually dimorphic spinal GRP system exists not only in mice but also in suncus, suggesting that this system is a conserved property in mammals. J. Comp. Neurol. 525:1586-1598, 2017. © 2016 Wiley Periodicals, Inc.

We used suncus (Suncus murinus; house musk shrew) to generate partner cells for cell fusion to produce suncus monoclonal antibodies. Suncus are insectivores that are genetically distant to rodents, and recognize antigens and epitopes that are not immunogenic in mice and rats, which are the animals most commonly used in basic life science research and from which monoclonal antibodies are usually produced. To date, monoclonal antibodies from suncus have not been generated due to the lack of a plasmacytoma fusion partner. To obtain suncus plasmacytoma cell lines suitable as a cell fusion partner, we injected suncus at both sides of the tail base with antigen emulsion, collected the lymph nodes and spleens, and cultured the cells to obtain immortalized lymphoid cell lines visually resembling mouse SP2/0-Ag14 myeloma cells. Three suncus immunized with the antigen provided 4 cell lines of suncus plasmacytoma, but they did not secrete immunoglobulins. Antibody-producing hybrid cells were generated from these cell lines using a cell fusion technique. Using one of the cell lines as a fusion partner, we obtained six lines of immunoglobulin-producing hybrid cells which secreted an unidentified monoclonal IgG. When these 6 lines were used as new fusion partners, we obtained several hybrid cell lines which secreted immunogen-specific monoclonal antibodies. These hybrid cells can be cloned and cryopreserved. We also obtained another good fusion partner which initially secreted antibody but later stopped doing so. These suncus-suncus hybrid cell lines will be useful for the production of suncus monoclonal antibodies.

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 Reunion 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.

Gastrin-releasing peptide (GRP) has recently been identified as an itch-signaling molecule in the primary afferents and spinal cord of rodents. However, little information exists on the expression and localization of GRP in the trigeminal somatosensory system other than in rats. We examined the generality of the trigeminal GRP system in mammals using two distinct species, suncus as a model of specialized placental mammals known to have a well-developed trigeminal sensory system and mice as a representative small laboratory animal. We first analyzed the gross morphology of the trigeminal somatosensory system in suncus to provide a brainstem atlas on which to map GRP distribution. Immunohistochemical analyses showed that 8% of trigeminal ganglion neurons in suncus and 6% in mice expressed GRP. Expression was restricted to cells with smaller somata. The GRP-containing fibers were densely distributed in the superficial layers of the caudal part of the trigeminal spinal nucleus (Vc) but rare in the rostral parts, both in suncus and mice. Expression of GRP receptor mRNA and protein was also detected in the Vc of suncus. Taken together, these results suggest that the trigeminal GRP system mediating itch sensation is conserved in mammals.

We used suncus (Suncus murinus; house musk shrew) to generate partner cells for cell fusion to produce suncus monoclonal antibodies. Suncus are insectivores that are genetically distant to rodents, and recognize antigens and epitopes that are not immunogenic in mice and rats, which are the animals most commonly used in basic life science research and from which monoclonal antibodies are usually produced. To date, monoclonal antibodies from suncus have not been generated due to the lack of a plasmacytoma fusion partner. To obtain suncus plasmacytoma cell lines suitable as a cell fusion partner, we injected suncus at both sides of the tail base with antigen emulsion, collected the lymph nodes and spleens, and cultured the cells to obtain immortalized lymphoid cell lines visually resembling mouse SP2/0-Ag14 myeloma cells. Three suncus immunized with the antigen provided 4 cell lines of suncus plasmacytoma, but they did not secrete immunoglobulins. Antibody-producing hybrid cells were generated from these cell lines using a cell fusion technique. Using one of the cell lines as a fusion partner, we obtained six lines of immunoglobulin-producing hybrid cells which secreted an unidentified monoclonal IgG. When these 6 lines were used as new fusion partners, we obtained several hybrid cell lines which secreted immunogen-specific monoclonal antibodies. These hybrid cells can be cloned and cryopreserved. We also obtained another good fusion partner which initially secreted antibody but later stopped doing so. These suncus-suncus hybrid cell lines will be useful for the production of suncus monoclonal antibodies.

The vertical distribution of introduced Siberian weasels Mustela sibirica and endemic Japanese weasels M. itatsi in the Seburi Mountains in Kyushu, Japan, was examined from October 1996 to February 1998. Siberian weasels occurred near villages with paddy and cultivated fields, whereas Japanese weasels occurred in grasslands and plantations. The dispersion of yearlings destabilized the distributions of both weasel species. The horizontal distribution of both species throughout Japan was examined by means of collection of dead specimens and by trapping from March 1998 to March 2002. The eastern boundary of the distribution of the Siberian weasel was Fukui, Nagano, and Aichi prefectures; however, the distribution is expanding slowly eastward. The Siberian weasel cannot invade new habitats that lack nearby villages in Seburi, and cannot expand its range in the eastern area of Aichi, where Japanese weasels are dominant. The presence of the Japanese weasel likely prevents expansion of the distribution of the Siberian weasel.

Wild-derived rat strains can provide novel genome resources that are not available in standard laboratory strains. Genetic backgrounds of wild-derived strains can facilitate effective genetic linkage analyses and often modulate the expression of mutant phenotypes. Here we describe the development and characterization of a new inbred rat strain, DOB/Oda, from wild rats (Rattus norvegicus) captured in Shitara, Aichi, Japan. Phenotype analysis of 109 parameters revealed that the DOB/Oda rats had small body weight, preference for darkness, and high locomotor activity compared with the rat strains in the National BioResource Project for the Rat (NBRP-Rat) database. Genome analysis with 357 SSLP markers identified DOB/Oda-specific alleles in 70 markers. The percentage of SSLP markers that showed polymorphism between the DOB/Oda strain and any of 132 laboratory strains from NBRP-Rat varied from 89 to 95 %. The polymorphic rate (average of the values of the percentage) for the DOB/Oda strain was 91.6 %, much higher than the rates for available wild-derived strains such as the Brown Norway rat. A phylogenic tree constructed with DOB/Oda and all the strains in NBRP-Rat showed that the DOB/Oda strain localized within the wild rat groups, apparently separate from the laboratory strains. Together, these findings indicated that the DOB/Oda rat has a unique genome that is not available in the laboratory strains. Therefore, the new DOB/Oda strain will provide an important genome resource that will be useful for designing genetic experiments and for the discovery of genes that modulate mutant phenotypes.

Objectives Alloxan generates hydrogen peroxide in the body, and a small amount of alloxan administered to acatalasemic mice results in diabetes. D-α-Tocopherol (vitamin E) is an antioxidant which helps prevent excess oxidation in the body. In this study, we examined the effect of vitamin E on diabetes caused by alloxan administration in mice. Methods Mice were maintained on a vitamin E-deprived diet and supplemented diet, respectively, for 14 weeks. Alloxan was then intraperitoneally administered, and blood glucose, glucose tolerance and the insulin level in mouse blood were examined. Results Hyperglycemia was observed in the mice maintained on the vitamin E-deprived diet. The incidence of hyperglycemia in the mice maintained on the vitamin E-deprived diet was significantly higher than that in the mice maintained on the supplemented diet. The abnormal glucose metabolism caused by alloxan administration was ameliorated by the vitamin E-supplemented diet. Conclusions It is deduced that vitamin E can prevent a decrease of insulin concentration in the blood in this mouse model.

Gastrin-releasing peptide (GRP) has recently been identified as an itch-signaling molecule in the primary afferents and spinal cord of rodents. However, little information exists on the expression and localization of GRP in the trigeminal somatosensory system other than in rats. We examined the generality of the trigeminal GRP system in mammals using two distinct species, suncus as a model of specialized placental mammals known to have a well-developed trigeminal sensory system and mice as a representative small laboratory animal. We first analyzed the gross morphology of the trigeminal somatosensory system in suncus to provide a brainstem atlas on which to map GRP distribution. Immunohistochemical analyses showed that 8% of trigeminal ganglion neurons in suncus and 6% in mice expressed GRP. Expression was restricted to cells with smaller somata. The GRP-containing fibers were densely distributed in the superficial layers of the caudal part of the trigeminal spinal nucleus (Vc) but rare in the rostral parts, both in suncus and mice. Expression of GRP receptor mRNA and protein was also detected in the Vc of suncus. Taken together, these results suggest that the trigeminal GRP system mediating itch sensation is conserved in mammals.

Reciprocal epithelial–mesenchymal interactions and several signalling pathways regulate the development of the genital tubercle (GT), an embryonic primordium of external genitalia. The morphology of the adult male external genitalia of the Asian house musk shrewSuncus murinus(hereafter, laboratory name: suncus) belonging to the order Eulipotyphla (the former order Insectivora or Soricomorpha) differs from those of mice and humans. However, the developmental process of the suncus GT and its regulatory genes are unknown. In the present study, we explored the morphological changes and gene expression patterns during the development of the suncus GT. Morphological observations suggested the presence of common (during the initial outgrowth) and species-specific (during the sexual differentiation of GT) developmental processes of the suncus GT. In gene expression analysis, fibroblast growth factor 8 (Fgf8) and sonic hedgehog (Shh), an indicator and regulator of GT development in mice respectively, were found to be expressed in the cloacal epithelium and the developing urethral epithelium of the suncus GT. This pattern of expression specifically in GT epithelium is similar to that observed in the developing mouse GT. Our results indicate that the mechanism of GT formation regulated by the FGF and SHH signalling pathways is widely conserved in mammals.

Skull morphological characters are used for species and subspecies identification in the manatees, but no comparative study has investigated skull growth. We examined progressive ossification in the cranial sutures of 251 skulls of West Indian manatees, 19 skulls of African manatees and 17 skulls of Amazonian manatees. Degrees of cranial suture fusion were evaluated based on gross observations of skull specimens. Our results suggest that ossification patterns in occipital region sutures follow a fixed sequence in living manatees. In all manatees, the suture between the sphenoid and occipital bones fused first, while the supraoccipital-exoccipital synchondrosis fused last. The ossification sequence observed in manatees was not found in descriptions of other mammals, including the dugong. We concluded that this ossification sequence is a unique, common character of living manatees. We also found two differences in the sequence of occipital region development in two subspecies of the West Indian ma...

Background It has been shown in human and canine studies that motilin, a gastroprokinetic hormone, induces gastric phase III contractions via the enteric nervous; however, the center of motilin action in the stomach has not been clearly revealed. In the present study, we investigated the neural pathway of motilin-induced gastric contraction by using Suncus murinus, a new animal model for motilin study. Methods An isolated suncus stomach was used in vitro to determine the mechanism of motilin action through the myenteric plexus. Synthetic suncus motilin (10−11–10−7 mol L−1) was added to an organ bath, and the spontaneous contraction response was expressed as a percent of ACh (10−5 mol L−1) responses. Motilin-induced contractions were also studied by a pharmacological method using several receptor antagonists and enzyme inhibitor. Key Results Suncus motilin induced a concentration-dependent gastric contraction at concentrations from 10−9 to 10−7 mol L−1. The responses to suncus motilin in the stomach were completely abolished by atropine and tetrodotoxin treatment and significantly suppressed by administration of hexamethonium, verapamil, phentolamine, yohimbine, ondansetron, and naloxone, whereas ritanserin, prazosin, timolol, and FK888 did not affect the action of motilin. Additionally, N-nitro l-arginine methylester slightly potentiated the contractions induced by motilin. Conclusions & Inferences The results indicate that motilin directly stimulates and modulates suncus gastric contraction through cholinergic, adrenergic, serotonergic, opioidergic, and NO neurons in the myenteric plexus.

We investigated sex ratio in seven populations of the Japanese pond turtle, Mauremys japonica, inhabiting ponds in the central region of Aichi Prefecture, Japan. The sex ratio, calculated as a numerical proportion (%) of males to total individuals sexed, was highly variable among the populations, ranging from no more than 20.0% to no less than 92.9%. Since M. japonica shows a temperature-dependent sex determination (TSD) with eggs producing more males under a relatively low incubation temperature and more females under a higher temperature, we hypothesized that the observed remarkable inter-population variation in sex ratio reflects that in the nest temperature. Our field observations indicated that the nesting sites of male-biased populations were largely shaded by wood, thus supposedly under a relatively low ambient temperature, while those of female-biased populations were located in open environments with direct exposure to solar heat. These results offer a circumstantial support to the above hypothesis. Remarkably skewed sex ratios observed in some populations might reflect the effect of substantial habitat fragmentation and severe nesting site limitation caused by recent artificial land development and changes in agricultural land use. If this is actually the case and the effect continues to operate, many of the M. japonica populations may eventually disappear.

Background Here we provide the most comprehensive study to date on the cranial ossification sequence in Lipotyphla, the group which includes shrews, moles and hedgehogs. This unique group, which encapsulates diverse ecological modes, such as terrestrial, subterranean, and aquatic lifestyles, is used to examine the evolutionary lability of cranial osteogenesis and to investigate the modularity of development. Results An acceleration of developmental timing of the vomeronasal complex has occurred in the common ancestor of moles. However, ossification of the nasal bone has shifted late in the more terrestrial shrew mole. Among the lipotyphlans, sequence heterochrony shows no significant association with modules derived from developmental origins (that is, neural crest cells vs. mesoderm derived parts) or with those derived from ossification modes (that is, dermal vs. endochondral ossification). Conclusions The drastic acceleration of vomeronasal development in moles is most likely coupled with the increased importance of the rostrum for digging and its use as a specialized tactile surface, both fossorial adaptations. The late development of the nasal in shrew moles, a condition also displayed by hedgehogs and shrews, is suggested to be the result of an ecological reversal to terrestrial lifestyle and reduced functional importance of the rostrum. As an overall pattern in lipotyphlans, our results reject the hypothesis that ossification sequence heterochrony occurs in modular fashion when considering the developmental patterns of the skull. We suggest that shifts in the cranial ossification sequence are not evolutionarily constrained by developmental origins or mode of ossification.

We describe morphological changes observed throughout the embryonic development of Mauremys japonica, a geoemydid species endemic to Japan. Eggs laid in captivity were incubated under two different temperature conditions, 26C and 30C. A total of 185 embryos and seven hatchlings were observed. We divided the whole embryonic development into 26 stages on the basis of morphological criteria previously proposed for Chelydra serpentina. Eggs of the turtle developed faster at 30C (taking 44–47 days for completion of the whole process) than at 26C (56–64 days). As has been reported previously, embryos of M. japonica developed to males after being incubated at 26C and to females at 30C, but without any visually recognizable differentiation in external morphology. Comparisons of embryos between M. japonica and three other testudinoid turtles revealed that the carapace of M. japonica started pigmentation at stage 18, i.e., earlier than the other three species by two stages.

The development of permanent premolar and molar teeth was examined in mandibular radiographs from wild sika deer (Cervus nippon) of known ages (74 males, 66 females, 4 unknown; age range 1–54 months) from Hyogo Prefecture. Tooth development was scored according to the method described by Brown & Chapman (1991a, b). Stage-specific scores for all molar and premolar teeth were summed, and simple cubic regression analysis was used to analyse the relationship between the total score and age in months. Our analysis showed a strong cubic correlation between the total score and chronological age in months. The equation obtained from this analysis was used to estimate age within a 95% prediction interval in seven archaeological specimens from the Asahi archaeological site in central Japan. Copyright © 2010 John Wiley & Sons, Ltd.

We investigated the effect of incubation temperature on hatchling sex in the Japanese pond turtle, Mauremys japonica. Eggs obtained from females collected in the Tokai District of Japan invariably produced males when incubated at constant temperatures from 22.0 to 28.0 C, whereas they produced only females under a higher temperature of 30.0 C. Both males and females hatched from eggs incubated at 28.5, 29.0, and 29.5 C. These results indicate that M. japonica has a mechanism of temperature-dependent sex determination (TSD) with higher temperatures favoring females and lower temperatures males as in several other species of the family Geoemydidae, as well as of a few other testudine families so far studied. The pivotal temperature and the transitional range of temperature (TRT) in M. japonica obtained by the inverse estimation from logistic regression were 28.8 C and from 27.8–29.8 C, respectively. Possible effect of TSD on the sex ratio observed in some wild populations of this turtle is discussed.

We examined changes in shell gathering in an early agricultural society at the head of Ise Bay, Japan based on the analysis of almost 20,000 individual shell remains from four coastal settlements. We analyzed historical changes in the composition and size range of the shell species Meretrix lusoria. The most common species went from Crassostrea gigas in the early Middle Yayoi period (about 400–350BC) to M. lusoria in the mid-Middle Yayoi period (about 320–200BC). It is possible that the seacoast tideland, an environment suitable for C. gigas, was buried in sediment from the rivers and thereby transformed into muddy sand bottoms, an environment more suitable for M. lusoria. We also analyzed historical changes in the size range of M. lusoria. The mean size of M. lusoria increased significantly from the early Final Jomon (about 1250–1000BC) to the late Early Yayoi (about 500–400BC), from the late Early Yayoi to the early Middle Yayoi, and from the early to the mid-Middle Yayoi periods. Evidence suggests that during the Yayoi period, the demand for shells decreased and therefore, the pressure to collect M. lusoria also decreased. We concluded that the larger specimens of M. lusoria were collected selectively.

We measured 145 bottlenose dolphin skulls to examine the effects of size on skull shape. We found that the rostral length and the width of the temporal fossa showed highly positive allometry. These differences, as a result of size, reflect the growth of the feeding apparatus. The positive allometry of the rostral length implies an extension of the range for food catching and an increase in mouth-closing speed. The positive allometry of the temporal fossa width reflects the development of the temporal muscle. On the other hand, the positive allometry of both the rostral length and the temporal fossa width seem to indicate a contradictory effect on occlusal force. However, the occlusal force estimated by bony characters increased by the condylobasal length. These trends were observed not only in immature specimens but also in mature specimens of different sizes. This fact means that the change of the skull shape in immature specimens is caused by the development of the feeding apparatus, while tha...

Karyological data on the lesser stripe-backed shrew, Sorex bedfordiae, were obtained from four specimens collected on Mt. Laojun, Lijiang District, Yunnan Province, China. Three of the four S. bedfordiae specimens had karyotypes consisting of 2n=26, NFa=44, with 4 metacentric, 4 submetacentric, 2 subtelocentric, and 2 acrocentric pairs, and 1 acrocentric X and acrocentric Y. This karyotype has the smallest diploid chromosome number in the XY group in the genus Sorex. The fourth specimen of S. bedfordiae had a different karyotype consisting of an additional pair of medium-sized metacentric chromosomes, i.e., 2n=28, NFa=48. These supernumerary chromosomes appear to constitute a new chromosome group in the genus Sorex and might provide new information concerning the taxonomy of soricid species.

We examined the fetal growth and development of the coypu (Myocastor coypus), a member of the Caviomorpha that produces extremely precocial young. Analyses of 69 fetuses derived from the latter half of the prenatal period (60–125 days of gestation) focused on external feature growth and development, tooth eruption, and cranial ossification. There were four developmental stages based on morphological characteristics; major external changes predominated over somatic growth in the early stages by 100–105 days of gestation, whereas the last stage was a time of rapid somatic growth. Growth rate was greater in hind foot length (4.3) than in fore foot length (3.4). Soft X-ray photos from 120 to 125 days of gestation show that the incisors, premolars, and first molars were completely calcified, and the second molars were present in the alveolus but not completely calcified. The occlusal surfaces of these teeth were subjected to wear. We analyzed the bone and cartilage of the coypu fetal cranium using a double-staining method. Early ossification of the jugular processes of the occipital bone was a prominent feature of coypu development. The digastric muscle originates on the jugular process, and early ossification should be linked to an adaptation to the herbivorous habit of weaned young coypu. Additionally, the sizes and closure times of six fontanelles are correlated with gestational age and are suggested as a comparative parameter for fetal maturity within and between mammalian species.

92008 ?? 33 1214 Received 2.8.2007 ; a cepted 5.5.2008 Copyright © 8 MSJ Introduction The ho s musk shrew (Suncus murinus) is one of 15 species in the genus Suncus (Abe 1985). This species is widely distributed from the Middle East and the Indian subcontinent to Southeast Asia, from tropical to subtropical regions, and its northernmost recorded habitat is in Nagasaki Prefecture, Japan (Corbet and Hill 1992). In Japan, the house musk shrew has been an established laboratory animal since 1973, and several laboratory strains currently exist (e.g., KAT, NAG, RYU, TESS; Oda 1991). This is the only widely used laboratory animal belonging to the Insectivora; suncus is utilized for a variety of purposes, including emesis studies (Ueno et al. 1987; Uchino et al. 2006). The house musk shrew exhibits extreme morphological variations. For example, its body weight varies threeto fourfold among wild populations: male shrews in Bangladesh weigh more than 150 g, while males in Guam are less than 50 g (Tomita et al. 1984; Ishikawa et al. 1989). Variations also exist in the dentition (Hanamura et al. 1979; Jogahara et al. 2007), chromosome number (Minesawa 1985), and coat color (Iseki et al. 1984; Ishikawa et al. 1986, 1987, 1989). Moreover, mutations in coat color (cream and white) and eye color (red-eyed dilution) occur in wild populations (Oda and Shigehara 1978; Ohno et al. 1992, 1994). The most prominent form of albinism in mice is a tyrosinase gene mutation that results in a white coat and red eyes (Beermann et al. 2004). However, mutations in other pigment genes result in diverse phenotypes in mice and humans (Tomita and Suzuki 2004; Hearing 2005). Thus, phenotypic observations cannot determine if the tyrosinase gene mutation is present. Moreover, individuals with a white coat and normal eye color occur in many species, including the house musk shrew (Oda and Shigehara 1978). Hence, an albino-like shrew is defined as one having a pure white coat and red eyes (Fig. 1a). Three albino-like house musk shrews were captured on Okinawa Island, Japan. In this report, past capture records of albino-like house musk shrews in the Ryukyu Archipelago were reviewed and integrated present capture records to determine their distribution. Additionally, the captured albino-like house musk shrews were maintained in the laboratory, and bred with the RYU strain of suncus established from Okinawa Island. The RYU strain had been kept for over 4 years and over 60 litters have been obtained, although no record exists of coat color variation or albinism and red eyes. This is thus a report of preliminary findings on the inheritance of the albino-like gene. Five albino-like house musk shrews from Okinawa and Tarama Islands have been recorded since 1968 (Table 1). Although the house musk shrew is a common

Wild populations of Suncus murinus from Nagasaki were thought to be extinct, although specimens from Nagasaki are kept at the National Science Museum, Tokyo. Variation in the number of teeth, including both congenital and postnatal absence, was observed in 25 of 85 individuals. All 25 abnormal individuals were checked using a micro-CT unit to document the presence or absence of embedded teeth and any traits of postnatal absence. Four of these had congenitally absent teeth, whereas the rest showed signs of postnatal absence. There was no significant difference in the ratio of length of tooth group P(4)M(3) against palatal length between individuals with congenital absent teeth and normal ones. Because S. murinus in captivity shows a high rate of periodontal disease, we suggest that the high rate of postnatal absence of teeth in the wild population is due to oral diseases such as periodontal disease or other traumatic factors.

We examined the skulls of 72 bottlenose dolphins from the Indian and western Pacific Oceans to clarify the systematics in genusTursiops. We also examined type skulls ofTursiops aduncus (Ehrenberg, 1832),T. eurynome (Gray, 1846),T. catalania (Gray, 1862),Delphinus (Steno) gadamu Owen 1866,T. dawsoni Lydekker 1908, andT. truncatus (Montagu, 1821). The specimens were divided into two groups, A and B, based on rostrum length and characters of the basal part of the rostrum. The rostrum of group A was longer and tapered abruptly near the base, whereas that of group B was shorter and tapered more gradually throughout its length. Group A contained specimens from western, central, and eastern Asia, Africa, and Australasia. Group B contained specimens from central and eastern Asia and Australasia. The six type skulls were also clearly divided into two groups; the type skulls ofT. aduncus, T. catalania, andDelphinus (Steno) gadamu were included in group A, whereas the type skulls ofT. truncatus, T. eurynome, andT. dawsoni were included in group B. This grouping was consistent with the genetic status. Therefore, we identified group A specimens asT. aduncus and group B specimensT. truncatus, the oldest scientific names related to the two groups.

Glutathione S-transferase (GST) theta 1 (GSTT1) has been regarded as one of the key enzymes involved in phase II reactions because of its unique substrate specificity. In this study, we generated mice with the disrupted Gstt1 gene (Gstt1-null mice) by gene targeting and analyzed the metabolic properties in cytosolic and in vivo studies. The resulting Gstt1-null mice failed to express the Gstt1 mRNA and GSTT1 protein by reverse transcriptase-polymerase chain reaction analysis and two-dimensional fluorescence difference gel electrophoresis/mass spectrometry analysis, respectively. However, the Gstt1-null mice appeared to be normal and were fertile. In an enzymatic study using cytosolic samples from the liver and kidney, GST activity toward 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP), dichloromethane (DCM), and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) was markedly lower in Gstt1-null mice than in the wild-type controls, despite there being no difference in GST activity toward 1-choloro-2,4-dinitrobenzene between Gstt1-null mice and the wild-type controls. Gstt1-null mice had GST activity of only 8.7 to 42.1% of the wild-type controls to EPNP, less than 2.2% of the wild-type controls to DCM, and 13.2 to 23.9% of the wild-type controls to BCNU. Plasma BCNU concentrations after a single i.p. administration of BCNU to Gstt1-null mice were significantly higher, and there was a larger area under the curve(5-60) min (male, 2.30 times; female, 2.28 times, versus the wild-type controls) based on the results. In conclusion, Gstt1-null mice would be useful as an animal model of humans with the GSTT1-null genotype.

We surveyed the central mountains and southeastern region of Taiwan and collected 11 specimens of a new species of mole, genus Mogera. The specimens were characterized by a small body size, dark fur, a protruding snout, and a long tail; these characteristics are distinct from those of the Taiwanese lowland mole, M. insularis (Swinhoe, 1862). A phylogenetic study of morphological, karyological and molecular characters revealed that Taiwanese moles should be classified as two distinctive species: M. insularis from the northern and western lowlands and the new species from the central mountains and the east and south of Taiwan. The skull of the new species was slender and delicate compared to that of M. insularis. Although the karyotypes of two species were identical, the genetic distance between them was sufficient to justify considering each as a separate species. Here, we present a detailed specific description of the new species and discuss the relationship between this species and M. insularis based on ecological characteristics and geographic distributions.

Karyotype ofSorex hosonoi Imaizumi, 1954 from Mt. Asama in central Honshu, Japan, were examined with conventional staining and G-banding using ASG methods. The diploid and fundamental autosomal arm numbers were 42 and 66, respectively. The autosomes consisted of seven metacentric, six submetacentric, and seven acrocentric pairs. The sex chromosomes were large-sized acrocentric X and small-sized subtelocentric Y. The relationship between the karyotypes ofS. hosonoi andS. shinto was explained by one pericentric inversion at the no. 5 ofS. hosonoi and the no. 9 ofS. shinto. A rearrangement inS. shinto-hosonoi differed from the rearrangements occurring on no. 5 ofS. shinto-caecutiens/unguiculatus.

The joggle mouse is a recessive ataxic mutant carrying an unknown mutation in a C3H/He (C3H)-derived chromosomal segment. Taking advantage of the mouse genome database, we selected 127 DNA microsatellite markers showing heterozygosity between C3H and C57BL/6J (B6) and a first round of screening for the joggle mutation was performed on B6-jog/+ partial congenic mice (N4). We identified 4 chromosomal regions in which 13 microsatellite markers show heterozygosity between C3H and B6. Then, we analyzed the genotype of these 4 chromosomal regions in mice that showed the joggle phenotype and mapped the jog locus between markers D6Mit104 (111.4 Mb) and D6Mit336 (125.1 Mb) (an interval of 13.7 Mb) on chromosome 6. By using a partial congenic strain together with the mouse genome database, we successfully mapped the chromosomal localization of the jog locus much more efficiently than by conventional linkage analysis.

We present the first karyological study on Kloss's mole Euroscaptor klossi from Chiang Rai Province of Thailand. We used differential chromosome staining methods and determined the diploid and fundamental autosomal numbers to be 36 and 54, respectively. Compared with the G- and C-banded karyotypes of the Japanese mountain mole E. mizura, the karyotype of E. klossi involved a reciprocal translocation followed by a pericentric inversion of chromosomes 1 and 16 of the ancestral karyotype of E. mizura. Some minor C-band duplications supplemented the karyological differences between the two species. The karyotype of E. klossi is distinct from that of the Malaysian mole E. micrura malayana examined previously and these species have distinct scenarios in diverging from the ancestral karyotype of the genus Euroscaptor.

Pepsinogens are zymogens of pepsins, the gastric digestive proteinases. Although pepsinogen A is predominant in most mammalian species hitherto known, pepsinogen C is expressed exclusively and the lack of pepsinogen A is evidenced in the rat and guinea pig. Furthermore, in these two rodents, considerable amount of procathepsin E is also expressed in gastric mucosa although it is almost undetectable in other mammals. In this paper, in order to clarify whether such unique gastric proteinase constitution is common among rodents, we carried out purification and characterization of gastric proteinases, and molecular cloning of pepsinogen-C cDNAs from several rodent species including the degu and coypu. Pepsinogen C and procathepsin E were isolated but pepsinogen A was undetectable in the rodents, leading to the conclusion that that rodents commonly share the unique gastric proteinase constitution. This feature could be treated as a new “molecular synapomorphy”, supporting strongly monophyly of the order Rodentia. From the molecular phylogenetic analyses of pepsinogen-C cDNA sequences, monophyly of the order Rodentia was also supported by the analyses with high statistic reliabilities.

We analyzed the skulls of 27 bottlenose dolphins (Tursiops spp.) from the waters around Japan to clarify their systematics. We divided the Japanese bottlenose dolphins into two morphological groups. Group A was comprised of six specimens from the coastal waters of the Amami Islands, Amakusa-Shimoshima Island, and Mikura Island. Group B included 21 specimens from other waters around Japan. Comparisons with type specimens showed that Groups A and B were identical to the types of T. aduncus and T. truncatus, respectively. These results support previous molecular studies on some specimens identified as T. aduncus.

Background: The pathogenesis and progression of periodontal disease have been extensively studied through the use of animal models. However, no animal model has yet been established that is precisely similar to periodontitis in humans. In the present study, we examined the use of Shiba goats as a model for spontaneous periodontitis. Methods: Thirty-four Shiba goats (seven males and 27 females, aged 10 to 98 months) were used. We examined periodontitis in Shiba goats clinically, histopathologically, and microbiologically. Results: The mean probing depth (PD) of the 68 teeth examined was 2.7 ± 0.8 mm. The incidences of PD ≥3 and 4 mm were 46.4% and 22.1%, respectively. The incidence of bleeding on probing in 68 sites and in 34 animals was 60.7% and 73.5%, respectively. The formation of vertical alveolar bone defects and downgrowth of gingival epithelial cells were found in the areas of periodontitis. The prevalence of Tannerella forsythensis, Campylobacter rectus, Fusobacterium necrophorum, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans in subgingival plaque by polymerase chain reaction was 46.4%, 28.5%, 28.5%, 17.8%, and 3.5%, respectively. These percentages were increased in subgingival plaque from PD ≥3 mm. Conclusions: The clinical, histopathological, and microbiological features of spontaneous periodontitis in Shiba goats were somewhat similar to those in human periodontitis. Moreover, there are some advantages of using the Shiba goat; the size of the oral cavity is suitable for periodontal treatment, and handling and housing are relatively easy. Therefore, these results suggest that the Shiba goat is a useful animal model for human periodontitis.