Microtus Rossiaemeridionalis Research Articles

Protein Polyacrylamide Gel Electrophoresis as a Common Vole Sibling Species Identification Method (Microtus arvalis Pallas, 1779 and M.rossiaemeridionalis Ognev, 1924 (Rodentia, Cricetidae))

A new protocol for the identification of two sibling species of voles Microtus arvalis and M. rossiaemeridionalis was proposed by electrophoresis of blood proteins in polyacrylamide gel (PAGE). Animals captured in ten districts of Moscow, Kaluga, and Samara oblasts and Moscow natural territories (1030 individuals), as well as those taken from vivarium collections (five hybrids of the two species), were studied. A comparison of electrophoresis in PAGE, agarose gel, and cellulose acetate plates was carried out. The use of different organs and tissues for species identification was assessed. The relative electrophoretic mobility and the mass of a species-specific blood protein of the southern vole were determined.

Species Composition, Distribution, and Environmental Ecology of Voles (Mammalia, Cricetidae, Microtus) Found in the Northwest Caucasus

Molecular genetic typing of voles from the vicinity of the Pslukh cordon (south of the Caucasian state reserve), Krasnaya Polyana, and from the Utrish reserve (the Abrau peninsula) has been carried out. Based on the nucleotide sequence of the mitochondrial cytochrome b gene, voles from Krasnaya Polyana and the Psulkh cordon should be attributed to Asia Minor voles (Chionomys roberti), and the animals from Utrish, to the Eastern European voles (Microtus rossiaemeridionalis). The Asia Minor voles belong to the North Caucasian phylogenetic branch of the species. The analysis of body measurements of voles from Krasnaya Polyana and Lazarevskii region (without molecular examination) showed that these animals also most likely belong to the Asia Minor voles (not to Gudaurskii, as was mistakenly considered earlier). Some information on the ecology of the Asia Minor voles in the region is given.

Assisted reproductive technologies in Microtus genus.

Background Microtus genus is one of the experimental animals showing unique characteristics, and some species have been used as various research models. In order to advance the utilization of Microtus genus, the development of assisted reproductive technologies (ARTs) is a key point. This review introduces recent progress in the development of ARTs for Microtus genus, especially Microtus montebelli (Japanese field vole).MethodsBased on previous and our publications, current status of the development of ARTs was summarized.ResultsIn M. montebelli, ARTs, such as superovulation, in vitro fertilization, intracytoplasmic sperm injection, embryo transfer, sperm cryopreservation, and nonsurgical artificial insemination, have considerably been established by using the procedures which were originally devised for mice and partly modified. However, when the methods for M. montebelli were applied to Microtus arvalis and Microtus rossiaemeridionalis, all protocols of ARTs except for sperm cryopreservation were technologically invalid.ConclusionAssisted reproductive technologies (ARTs) are considerably established in M. montebelli, and this fact allows this species to be potentially useful as a model animal. However, since ART protocols of M. montebelli are mostly invalid for other species of the Microtus genus, it is necessary to improve them specifically for each of other species.

Characterization of the complete mitochondrial genome of short-tailed field vole, Microtus agrestis

In this study, the complete mitochondrial genome of short-tailed field vole, Microtus agrestis, was determined through sequencing of PCR fragments. The complete mitochondrial genome of M. agrestis was 16,538 bp in length and encoded 13 protein-coding genes, 22 transfer RNA (tRNA) genes, and two ribosomal RNA genes. The overall nucleotide composition is: 15.7% A, 27.5% T, 25.5% C, and 31.4% G, with a total G + C content of 56.9%. By phylogenetic analysis using Bayesian method, M. agrestisa showed the closest relationship with the southern vole (Microtus rossiaemeridionalis).

Habitat use of coexisting Microtus vole species under competition and predation risk

Competing species and predators can alter the habitat use of animals, but both factors are rarely simultaneously controlled. We studied in experimental enclosures how closely related species, the sibling vole (Microtus levis Miller, 1908) and the field vole (Microtus agrestis (Linnaeus, 1761)), adjust their habitat use when facing either the competing species or simultaneously competition and predation risk. The species responded differently in their proportional use of two habitat types, a low cover (productive but riskier) and a high cover (safer but poorer). When alone, field voles used the low-cover habitat according to availability at low densities, but decreased its use with increasing density. Sibling voles, however, avoided the low-cover habitat in single-species populations. Under interspecific competition, the habitat-use patterns switched between species: sibling voles used the low-cover habitat according to availability, with decreasing use as densities increased. Sibling voles responded to predation risk by showing a stronger density-dependent decrease in the use of low-cover habitat. Field voles, initially using mostly high cover, did not change behaviour under risk of predation. Our results highlight the importance of considering both predation risk and interspecific competition when interpreting patterns of habitat selection among coexisting species.

The complete mitochondrial genome of the common vole, Microtus arvalis (Rodentia: Arvicolinae)

The common vole, Microtus arvalis belongs to the genus Microtus in the subfamily Arvicolinae. In this study, the complete mitochondrial genome of M. arvalis was recovered using shotgun sequencing and an iterative mapping approach using three related species. Phylogenetic analyses using the sequence of 21 arvicoline species place the common vole as a sister species to the East European vole (Microtus levis), but as opposed to previous results we find no support for the recognition of the genus Neodon within the subfamily Arvicolinae, as this is, as well as the genus Lasiopodomys, found within the Microtus genus.

Impact of Xist RNA on chromatin modifications and transcriptional silencing maintenance at different stages of imprinted X chromosome inactivation in vole Microtus levis.

In vole Microtus levis, cells of preimplantation embryo and extraembryonic tissues undergo imprinted X chromosome inactivation (iXCI) which is triggered by a long non-coding nuclear RNA, Xist. At early stages of iXCI, chromatin of vole inactive X chromosome is enriched with the HP1 heterochromatin-specific protein, trimethylated H3K9 and H4K20 attributable to constitutive heterochromatin. In the study, using vole trophoblast stem (TS) cells as a model of iXCI, we further investigated chromatin of the inactive X chromosome of M. levis and tried to find out the role of Xist RNA. We demonstrated that chromatin of the inactive X chromosome in vole TS cells also contained the SETDB1 histone methyltransferase and KAP1 protein. In addition, we observed that Xist RNA did not contribute significantly to maintenance of X chromosome inactive state during iXCI in vole TS cells. Xist repression affected neither transcriptional silencing caused by iXCI nor maintenance of trimethylated H3K9 and H4K20 as well as HP1, KAP1, and SETDB1 on the inactive X chromosome. Moreover, the unique repertoire of chromatin modifications on the inactive X chromosome in vole TS cells could be disrupted by a chemical compound, DZNep, and then restored even in the absence of Xist RNA. However, Xist transcript was necessary for recruitment of an additional repressive histone modification, trimethylated H3K27, to the inactive X chromosome during vole TS cell differentiation.

What Can an Invasive Species Tell Us about Evolution? A Study of Dental Variation in Disjunctive Populations of Microtus rossiaemeridionalis (Arvicolinae, Rodentia)

The sibling vole, Microtus rossiaemeridionalis, is a North Eurasian rodent that undergoes range expansion via casual introductions by humans. The documented cases of human-mediated spread of M. rossiaemeridionalis provide an opportunity to explore phenotypic consequences associated with the invasion events. We present an analysis of dental variability in two recently discovered invasive populations of M. rossiaemeridionalis in northern Asia (Surgut and Khabarovsk) and summarize the data on conspecifics within and outside the core range in order to uncover common and specific patterns of dental variation in the disjunctive invasive populations, and to consider the potential evolutionary significance of the phenotypic effects from neontological and paleontological standpoints. The analysis of morphotype dental patterns and inspection for rare traits suggest that the existence of invasive populations under conditions of isolation leads to a release of hidden phenotypic variation, which could be inferred from sharp increases in frequencies of reserve morphotypes and/or rare dental traits, and also from the presence of abnormalities. An atavistic anomaly of the third upper molars revealed in one individual in a fragmented habitat in Surgut recapitulates some features of the prismatic arrangement and occlusal pattern of extinct Mimomys-like arvicolines. All variants of released phenotypic variation in the invasive populations of M. rossiaemeridionalis under conditions of isolation could be interpreted as de-specialization of dentition. Such de-specialization appears to be maladaptive for a herbivore, though it might favor a transition to a more generalized diet and enhance the success during the transport, colonization, and establishment stages of the invasion.

The first finding of East European vole (Microtus rossiaemeridionalis) in Buryatia

The first finding of the East European vole Microtus rossiaemeridionalis in Transbaikalia is reported.

К ВИДОВОМУ СОСТАВУ, РАСПРОСТРАНЕНИЮ И ЭКОЛОГИИ ПОЛЁВОК (MAMMALIA, CRICETIDAE, MICROTINA) СЕВЕРО-ЗАПАДНОГО КАВКАЗА

Molecular-genetic typing was done for voles in the vicinity of the Pslukh forest station (the south of the Caucasus nature reserve), the Krasnaya Polyana, and the Utrish nature reserve (the Abrau peninsula). Based on the nucleotide sequence of the mitochondrial cytochrome b gene, the voles from the Krasnaya Polyana and Pslukh station were attributed to Robert’s snow vole (Chionomys roberti), whereas the animals from the Utrish nature reserve belong to the Eastern-European vole (Microtus rossiaemeridionalis). Robert’s snow voles belong to the Northern Caucasian phylogenetic branch of the species. Our analysis of body measurements of the voles from the Krasnaya Polyana and Lazarevsky district (without molecular examination) has shown that these animals most probable also belong to Robert’s snow voles rather than to the Gudaur snow voles as they were erroneously attributed earlier. Data on the ecology of Robert’s snow voles in the region are presented.

Infestations of flea species on small, wild mammals in the provinces of Aydın and Manisa in the Aegean Region, Turkey*

This study was carried out to determine flea species infesting small, wild rodents and insectivorous wild mammals of the Aegean Region in Turkey. A total of 52 small, wild mammals, comprising one insectivorous and four rodent species, namely Crocidura suaveolens , Mus macedonicus , Apodemus flavicollis , Microtus levis , and Apodemus witherbyi , were captured. Fleas were collected, preserved in 70% alcohol, and labelled for identification in the field. In the laboratory, they were cleared in 10% KOH and mounted with Hoyer's medium. The fleas were identified as Stenoponia tripectinata (Tiraboschi, 1902) from Mus macedonicus (12.8%) and Nosopsyllus fasciatus (Bosc, 1800) from M. macedonicus (2.5%) and also from M. levis (100%). One out of the 5 C. suaveolens was infested by S. tripectinata. Two species of fleas were found on 8 of the 47 rodents and one of the 5 insectivorous mammals was infested by S. tripectinata . The flea species and their hosts should be further investigated for zoonotic pathogens.

Induced Pluripotent Stem Cells of Microtus levis x Microtus arvalis Vole Hybrids: Conditions Necessary for Their Generation and Self-Renewal

Every year, the list of mammalian species for which cultures of pluripotent stem cells (PSCs) are generated increases. PSCs are a unique tool for extending the limits of experimental studies and modeling different biological processes. In this work, induced pluripotent stem cells (iPSCs) from the hybrids of common voles Microtus levis and Microtus arvalis, which are used as model objects to study genome organization on the molecular-genetic level and the mechanisms of X-chromosome inactivation, have been generated. Vole iPSCs were isolated and cultured in a medium containing cytokine LIF, basic fibroblast growth factor (bFGF), ascorbic acid, and fetal bovine serum. Undifferentiated state of vole iPSCs is maintained by activation of their endogenous pluripotency genes - Nanog, Oct4, Sox2, Sall4, and Esrrb. The cells were able to maintain undifferentiated state for at least 28 passages without change in their morphology and give rise to three germ layers (ectoderm, mesoderm and endoderm) upon differentiation.

The first complete mitochondrial genome of the Microtus ochrogaster

Microtus ochrogaster, a small vole, found in central North America. Recently the genome sequencing had been done, but no more information of its mitochondrial reported. Herein, we first assembled the complete mitochondrial genome sequence of Microtus ochrogaster. It is a 16 292 bp long sequence with most mitogenome’s characteristic structure, 13 protein-coding genes, two of rRNA genes, 22 of tRNA genes, one D-loop region, one repeat region, and three STS regions. The GC-content of our fresh sequence is 40%. It can verify the accuracy and utility of new determined mitogenome sequences by the phylogenetic analysis, based on the whole mitogenome alignment with Microtus fortis calamorum, Microtus levis, and Microtus rossiaemeridionalis, which is closest relative to Microtus ochrogaster. We expect that using the full mitogenome to address taxonomic issues and study the related evolution events.

Surviving in the High Arctic: dental variation in a casually introduced population of Microtus rossiaemeridionalis (Arvicolinae, Rodentia) on Svalbard

AbstractA human‐mediated invasion of a temperate rodent Microtus rossiaemeridionalis on the High Arctic Archipelago of Svalbard in the first half of the 20th century provides an opportunity to explore extent and rate of morphological divergence over decades of isolation. We studied dental size and morphology in 124 voles captured on Svalbard (Spitsbergen) in 1997–2005 and compared the data to mainland conspecific populations across northern Eurasia. Both dental and cranial sizes in the Svalbard population fall within the limits of natural variation of the species. Dental morphology suggests that the population experiences strong effects of isolation as indicated by the significant increase in the frequency of rare dental morphs, possibly caused by inbreeding. No evidence for directional shift towards increased or decreased complexity of the morphotype dental patterns is revealed. Although the population on Svalbard is phenotypically different from the mainland populations (due to increased frequency of rare morphs), those differences are not enough to support the idea of initial rapid evolution related to colonization. The limited spatial extent and environmental homogeneity of suitable habitats on the island allowed the species to initially multiply but not to diversify so that the species exhibits phenotypic conservatism but suffers the consequences of small population size.

Morphological and morphometric characterization of the new records of the East European vole (Microtus levis Miller, 1908) from northeast Iran

Thirteen specimens of Microtus levis were collected from Golestan province, northeast Iran. The specimens were studied based on their external characters, skull and dental morphology, and specially karyology. Specimens of M. levis from the northeast of Iran were also compared with other species of the arvalis group from Iran and specimens of M. levis from Turkey. The specimens demonstrated that 2n=54 and fundamental number FN=54. The karyological results were similar between specimens from northeast Iran and those from Turkey, but they were different from specimens of Europe. In addition, the morphometric characters of M. levis, including head and body length (mean=105.77±7.53), length of condylobasal (mean=24.96±0.97), length of bullae (mean=6.57±0.34), and dental characters consisting of maxillary tooth row (mean=6.17±0.25) and mandibular tooth row (mean=5.60±0.33), were different from those of other species of the arvalis group.

Mapping of Replication Origins in the X Inactivation Center of Vole Microtus levis Reveals Extended Replication Initiation Zone.

DNA replication initiates at specific positions termed replication origins. Genome-wide studies of human replication origins have shown that origins are organized into replication initiation zones. However, only few replication initiation zones have been described so far. Moreover, few origins were mapped in other mammalian species besides human and mouse. Here we analyzed pattern of short nascent strands in the X inactivation center (XIC) of vole Microtus levis in fibroblasts, trophoblast stem cells, and extraembryonic endoderm stem cells and confirmed origins locations by ChIP approach. We found that replication could be initiated in a significant part of XIC. We also analyzed state of XIC chromatin in these cell types. We compared origin localization in the mouse and vole XIC. Interestingly, origins associated with gene promoters are conserved in these species. The data obtained allow us to suggest that the X inactivation center of M. levis is one extended replication initiation zone.

Olfactory environment of commensal house mice as a factor that affects the formation of the species composition of the population of rodents in buildings

It was demonstrated that in Y-maze individuals of the outdoor species Myodes glareolus and the semi-synanthropic species Microtus levis avoided the urine odor of commensal Mus musculus. On the contrary mice stayed longer in the maze compartment with the odor of voles. The level of avoidance of commensal mice odor was higher than the other strange odors (urine of rabbit or outdoor mouse Mus spicilegus). It is assumed that the sharp smell of commensal mice is an adaptation designed to hold and protect a particular ecological niche against other species of rodents, i.e., human buildings.

Gradient of rodent species diversity across altitudes in Hyrcanian region, northeast Iran

During the three-year long study of the rodent community, a total of 139 individuals belonging to three families and eleven species were investigated. The studied rodent families included Muridae, (Mus musculus, Nesokia indica, Rattus norvegicus, Rattus rattus, Apodemus witherbyi, Apodemus hyrcanicus, Apodemus uralensis, and Rhombomys opimus), Gliridae (Glis glis), and Cricetidae, (Microtus levis, Cricetulus migratorius). Specimens were captured with modified Sherman live traps at four altitude levels covering clay plains around Alagol and Almagol wetlands, the sub-mountainous range of Hyrcanian forests, the Alborz Mountain range, and steppes of the northern slopes of the Alborz Mountain range in the easternmost part of the Hyrcanian region, northeast of Iran. Shannon–Wiener’s, Simpson’s diversity and evenness indices were calculated. Our data showed that species diversity varies with vegetation coverage. Moreover, species richness and evenness indices show the tendency to decrease with increasing altitud...

Molecular and cytogenetic evidence for the occurrence of the East European vole Microtus rossiaemeridionalis (Arvicolinae, Rodentia) in the North of West Siberia.

Molecular and cytogenetic evidence for the occurrence of the East European vole Microtus rossiaemeridionalis (Arvicolinae, Rodentia) in the North of West Siberia.

Dynamics of the Two Heterochromatin Types during Imprinted X Chromosome Inactivation in Vole Microtus levis

In rodent female mammals, there are two forms of X-inactivation – imprinted and random which take place in extraembryonic and embryonic tissues, respectively. The inactive X-chromosome during random X-inactivation was shown to contain two types of facultative heterochromatin that alternate and do not overlap. However, chromatin structure of the inactive X-chromosome during imprinted X-inactivation, especially at early stages, is still not well understood. In this work, we studied chromatin modifications associated with the inactive X-chromosome at different stages of imprinted X-inactivation in a rodent, Microtus levis. It has been found that imprinted X-inactivation in vole occurs in a species-specific manner in two steps. The inactive X-chromosome at early stages of imprinted X-inactivation is characterized by accumulation of H3K9me3, HP1, H4K20me3, and uH2A, resembling to some extent the pattern of repressive chromatin modifications of meiotic sex chromatin. Later, the inactive X-chromosome recruits trimethylated H3K27 and acquires the two types of heterochromatin associated with random X-inactivation.