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the dynamics of health in wild field vole populations: a haematological perspective.1. pathogens have been proposed as potentially important drivers of population dynamics, but while a few studies have investigated the impact of specific pathogens, the wealth of information provided by general indices of health has hardly been exploited. by evaluating haematological parameters in wild populations, our knowledge of the dynamics of health and infection may be better understood. 2. here, haematological dynamics in natural populations of field voles are investigated to determine en ...200818564292
are silica defences in grasses driving vole population cycles?understanding the factors that drive species population dynamics is fundamental to biology. cyclic populations of microtine rodents have been the most intensively studied to date, yet there remains great uncertainty over the mechanisms determining the dynamics of most of these populations. for one such population, we present preliminary evidence for a novel mechanism by which herbivore-induced reductions in plant quality alter herbivore life-history parameters and subsequent population growth. w ...200818482904
natal conditions alter age-specific reproduction but not survival or senescence in a long-lived bird of prey.1. natal conditions and senescence are two major factors shaping life-history traits of wild animals. however, such factors have rarely been investigated together, and it remains largely unknown whether they interact to affect age-specific performance. 2. we used 27 years of longitudinal data collected on tawny owls with estimates of prey density (field voles) from kielder forest (uk) to investigate how prey density at birth affects ageing patterns in reproduction and survival. 3. natal conditio ...201121466554
voles on small islands: effects of food limitation and alien predation.ecosystems of three trophic levels may be bottom-up (by food-plant availability) and/or top-down (by predators) limited. top-down control might be of greater consequence when the predation impact comes from an alien predator. we conducted a replicated two-factor experiment with field voles (microtus agrestis) during 2004-2005 on small islands of the outer archipelago of the baltic sea, south-west finland, manipulating both predation impact by introduced american mink (mustela vison) and winter f ...200818607635
guild composition and habitat use of voles in 2 forest landscapes in south-eastern norway.it is widely believed that intensive forestry has influenced small mammal population dynamics, and thereby the entire mammalian community in fennoscandian boreal forests. the nature of these impacts on the different species is subject to debate. we live-trapped voles between 2006 and 2009 in 2 commercially harvested forests in south-eastern norway. we investigated the variation in vole abundance among habitat types (e.g. mature forest and clear-cut) and the hypothesis that graminivorous species ...201122182322
photoperiod regulates leptin sensitivity in field voles, microtus agrestis.we have previously shown that cold-acclimated (8 degrees c) male field voles (microtus agrestis) transferred from short (sd, 8:16 h l:d) to long photoperiod (ld, 16:8 h l:d) exhibit increases in body mass, adiposity and food intake. to assess whether these increases were associated with decreased leptin sensitivity, we infused ld and sd voles with physiological doses of murine leptin (or saline) delivered peripherally for 7 days via mini-osmotic pumps. measurements were made of body mass (weight ...200616402185
whole-genome chromosome distribution during nuclear fragmentation of giant trophoblast cells of microtus rossiaemeridionalis studied with the use of gonosomal chromatin arrangement.gonosomal chromatin bodies (gcbs), i.e. blocks of condensed chromatin consisting of heterochromatized region of the sex chromosomes of the field vole m. rossiaemeridionalis, were used as a natural interphase chromosome marker in order to clarify the regularities of gcb rearrangement during nuclear fragmentation of secondary giant trophoblast cells (sgtcs) at the end of their differentiation. cytophotometrical measurements of dna content in the nuclei, nuclear fragments and simultaneously in the ...200516314124
post-glacial partitioning of mitochondrial genetic variation in the field vole.genetic markers are often used to examine population history. there is considerable debate about the behaviour of molecular clock rates around the population-species transition. nevertheless, appropriate calibration is critical to any inference regarding the absolute timing and scale of demographic changes. here, we use a mitochondrial cytochrome b gene genealogy, based entirely on modern sequences and calibrated from recent geophysical events, to date the post-glacial expansion of the eurasian ...201121508032
the analysis of immunological profiles in wild animals: a case study on immunodynamics in the field vole, microtus agrestis.a revolutionary advance in ecological immunology is that postgenomic technologies now allow molecular mediators defined in laboratory models to be measured at the mrna level in field studies of many naturally occurring species. here, we demonstrate the application of such an approach to generate meaningful immunological profiles for wild mammals. we sampled a natural field vole population across the year (n = 307) and developed a battery of cellular assays in which functionally different pro- an ...201121059128
comparative analysis by chromosome painting of the sex chromosomes in arvicolid rodents.sex chromosome evolution in mammals has been extensively investigated through chromosome-painting analyses. in some rodent species from the subfamily arvicolinae the sex chromosomes contain remarkable features such as giant size, a consequence of heterochromatic enlargement, or asynaptic behaviour during male meiosis. here, we have made a comparative study of the sex chromosomes in 6 arvicolid species using different probes from the x and y chromosomes of 3 species, in order to gain knowledge ab ...201120689262
phenotypic evolution of dispersal-enhancing traits in insular voles.evolutionary theory predicts that in metapopulations subject to rapid extinction-recolonization dynamics, natural selection should favour evolution of traits that enhance dispersal and recolonization ability. metapopulations of field voles (microtus agrestis) on islands in the stockholm archipelago, sweden, are characterized by frequent local extinction and recolonization of subpopulations. here, we show that voles on the islands were larger and had longer feet than expected for their body size, ...201120685710
chromosomal evolution of arvicolinae (cricetidae, rodentia). iii. karyotype relationships of ten microtus species.the genus microtus consists of 65 extant species, making it one of the rodentia genera with the highest number of species. the extreme karyotype diversification in microtus has made them an ideal species group for comparative cytogenetics and cytotaxonomy. conventional comparative cytogenetic studies in microtus have been based mainly on chromosomal banding patterns; the number of microtus species examined by molecular cytogenetics-cross-species chromosome painting-is limited. in this study, we ...201020379801
xenobiotic metabolism of bank vole (myodes glareolus) exposed to pcdds.previous studies in bank vole (myodes glareolus) and field vole (microtus agrestis) living at the old sawmill area contaminated by chlorinated dibenzo-p-dioxins and -furans (pcdd/fs) showed that these two relatively close species have a significant difference in their body burden of pcdd/fs, bank voles having significantly higher concentrations. the aim of this study was to clarify more comprehensively the basic xenobiotic metabolism in wild bank voles and examine whether pcdd exposure would aff ...201021787577
individual growth rates in natural field vole, microtus agrestis, populations exhibiting cyclic population dynamics.rodents that have multi-annual cycles of density are known to have flexible growth strategies, and the "chitty effect", whereby adults in the high-density phase of the cycle exhibit larger average body mass than during the low phase, is a well-documented feature of cyclic populations. despite this, there have been no studies that have repeatedly monitored individual vole growth over time from all phases of a density cycle, in order to evaluate whether such variation in body size is due to differ ...201019916066
choice of voles among genotypes of birch seedlings: its relationship with seedling quality and preference of insects.selective feeding by herbivores on establishing seedlings has been suggested to affect genotype frequencies in several plant populations. the existence of genotypes susceptible to herbivores calls for an explanation in such populations. in the present study we assessed the choice of multiple herbivores, field voles (microtus agrestis) and insects, among genotypes of silver birch (betula pendula) representing variation occurring in a naturally regenerated stand. we examined how food choice of vol ...200228547050
predation and fragmentation portrayed in the statistical structure of prey time series.statistical autoregressive analyses of direct and delayed density dependence are widespread in ecological research. the models suggest that changes in ecological factors affecting density dependence, like predation and landscape heterogeneity are directly portrayed in the first and second order autoregressive parameters, and the models are therefore used to decipher complex biological patterns. however, independent tests of model predictions are complicated by the inherent variability of natural ...200919419539
apoptosis-related factors (fas receptor, fas ligand, fadd) in early tooth development of the field vole (microtus agrestis).fas (cd95/apo-1) belongs to the tnf receptor (tnfr) family. fas ligand binding followed by fas-receptor oligomerisation leads to formation of a death-inducing signal complex starting with recruitment of the fas-adapter protein (fadd). components of this initiation complex (fas, fas-l, fadd) were correlated with apoptotic cells, detected by specific dna fragmentation and morphological criteria. apoptotic cells can be detected throughout the embryonic development of molar teeth. restricted temporo ...200515721145
effect of photoperiod on body mass, food intake and body composition in the field vole, microtus agrestis.many small mammals respond to seasonal changes in photoperiod by altering body mass and adiposity. these animals may provide valuable models for understanding the regulation of energy balance. here, we present data on the field vole (microtus agrestis) - a previously uncharacterised example of photoperiod-induced changes in body mass. we examined the effect of increased day length on body mass, food intake, apparent digestive efficiency, body composition, de novo lipogenesis and fatty acid compo ...200515671345
optimal body size and energy expenditure during winter: why are voles smaller in declining populations?winter is energetically challenging for small herbivores because of greater energy requirements for thermogenesis at a time when little energy is available. we formulated a model predicting optimal wintering body size, accounting for the scaling of both energy expenditure and assimilation to body size, and the trade-off between survival benefits of a large size and avoiding survival costs of foraging. the model predicts that if the energy cost of maintaining a given body mass differs between env ...200415026979
a highly divergent mitochondrial dna lineage of microtus agrestis in southern europe.the mediterranean peninsulas constitute important areas for endemism and intraspecific variation, and are likely places for cryptic biodiversity. we assessed the phylogeographic pattern of field voles (microtus agrestis) in southern and central europe by sequence analysis of a 385-bp fragment of the mitochondrial cytochrome b gene in 74 specimens from 44 localities. the majority of samples consisted of skulls collected from owl pellets. the data revealed a highly distinct cytochrome b lineage in ...200414666134
the impact of experimentally elevated energy expenditure on oxidative stress and lifespan in the short-tailed field vole microtus agrestis.life-history theory assumes that animal life histories are a consequence of trade-offs between current activities and future reproductive performance or survival, because resource supply is limited. empirical evidence for such trade-offs in the wild are common, yet investigations of the underlying mechanisms are rare. life-history trade-offs may have both physiological and ecological mediated costs. one hypothesized physiological mechanism is that elevated energy metabolism may increase reactive ...200818467297
preliminary observations of the cytological structure of the hypothalamo-neurohypophyseal magnocellular neuroendocrine system in field voles after acute thermal stress. 199910352964
polymorphic microsatellite dna markers in the field vole microtus montebelli. 19999919707
poor condition and infection: a vicious circle in natural populations.pathogens may be important for host population dynamics, as they can be a proximate cause of morbidity and mortality. infection dynamics, in turn, may be dependent on the underlying condition of hosts. there is a clear potential for synergy between infection and condition: poor condition predisposes to host infections, which further reduce condition and so on. to provide empirical data that support this notion, we measured haematological indicators of infection (neutrophils and monocytes) and co ...200818448414
delayed density-dependent season length alone can lead to rodent population cycles.studies of cyclic microtine populations (voles and lemmings) have suggested a relationship between the previous year's population density and the subsequent timing of the onset of reproduction by overwintered breeding females. no studies have explored the importance of this relationship in the generation of population cycles. here we mathematically examine the implications of variation in reproductive season length caused by delayed density-dependent changes in its start date. we demonstrate tha ...200616671013
effects of a soft diet and hypothyroidism on the oxidative capacity of the masseter muscle fibers of the young japanese field vole microtus montebelli.effects of a soft diet (reduction in mastication activity: an exogenous factor) and hypothyroidism (endogenous factors) on the oxidative capacity of the masseter muscles in the young japanese field vole microtus montebelli, consisting only of fast-twitch oxidative (fo) fibers in the adult vole, was investigated histochemically and electron microscopically. oxidative enzyme activity and mitochondrial development in the muscle fibers were not affected by a soft diet, while they were suppressed by ...19989615621
changes over time in the spatiotemporal dynamics of cyclic populations of field voles (microtus agrestis l.).we demonstrate changes over time in the spatial and temporal dynamics of an herbivorous small rodent by analyzing time series of population densities obtained at 21 locations on clear cuts within a coniferous forest in britain from 1984 to 2004. changes had taken place in the amplitude, periodicity, and synchrony of cycles and density-dependent feedback on population growth rates. evidence for the presence of a unidirectional traveling wave in rodent abundance was strong near the beginning of th ...200616671000
regulation of body mass and adiposity in the field vole, microtus agrestis: a model of leptin resistance.adult mammals are typically highly resistant to perturbations in their energy balance. in obese humans, however, this control appears to be lost. apart from a few exceptional cases, this loss of control occurs despite appropriate levels of circulating leptin -- suggesting that elevated adiposity may be a consequence of failure to respond to the leptin signal: leptin resistance. when cold-acclimated male field voles (microtus agrestis) are transferred from short (sd, 8 h light) to long (ld, 16 h ...200717283227
altered expression of socs3 in the hypothalamic arcuate nucleus during seasonal body mass changes in the field vole, microtus agrestis.we have previously shown that cold-acclimated (8 degrees c) male field voles (microtus agrestis) transferred from short day (sd, 8 h light) to long day (ld, 16 h light) photoperiod exhibit an increase in body mass lasting 4 weeks, after which they stabilise at a new plateau approximately 7.5 g (24.8%) higher than animals maintained in sd. by infusing voles with exogenous leptin, we have also demonstrated that sd voles respond to the hormone by reducing body mass and food intake, whereas ld anima ...200717214870
costs of coexistence along a gradient of competitor densities: an experiment with arvicoline rodents.1. costs of coexistence for species with indirect resource competition usually increase monotonically with competitor numbers. very little is known though about the shape of the cost function for species with direct interference competition. 2. here we report the results of an experiment with two vole species in artificial coexistence in large enclosures, where density of the dominant competitor species (microtus agrestis) was manipulated. experimental populations of the subordinate vole species ...200717184354
incomplete sister chromatid separation of long chromosome arms.chromosome segregation ensures the equal partitioning of chromosomes at mitosis. however, long chromosome arms may pose a problem for complete sister chromatid separation. in this paper we report on the analysis of cell division in primary cells from field vole microtus agrestis, a species with 52 chromosomes including two giant sex chromosomes. dual chromosome painting with probes specific for the x and the y chromosomes showed that these long chromosomes are prone to mis-segregate, producing d ...200617021850
resting and daily energy expenditures of free-living field voles are positively correlated but reflect extrinsic rather than intrinsic effects.resting metabolic rates at thermoneutral (rmrts) are unexpectedly variable. one explanation is that high rmrts intrinsically potentiate a greater total daily energy expenditure (dee), but recent work has suggested that dee is extrinsically defined by the environment, which independently affects rmrt. this extrinsic effect could occur because expenditure is forced upwards in poor habitats or enabled to rise in good habitats. we provide here an intraspecific test for an association between rmrt an ...200314615588
quantitative investigation of reproduction of gonosomal condensed chromatin during trophoblast cell polyploidization and endoreduplication in the east-european field vole microtus rossiaemeridionalis.simultaneous determinations of dna content in cell nuclei and condensed chromatin bodies formed by heterochromatized regions of sex chromosomes (gonosomal chromatin bodies, gcb) have been performed in two trophoblast cell populations of the east-european field vole microtus rossiaemeridionalis: in the proliferative population of trophoblast cells of the junctional zone of placenta and in the secondary giant trophoblast cells. one or two gcbs have been observed in trophoblast cell nuclei of all e ...200312725646
artificial reproduction of the yangtze field vole: in vitro embryo development and fertilization with fresh and freeze-thawed sperm.several research groups are using the yangtze field vole as a model for studying schistosome infection, but relatively little is known about the species's reproductive physiology. the authors examined the vole's in vivo and in vitro embryonic development as well as the efficacy of in vitro fertilization using either fresh or cryopreserved sperm to breed these rodents.200616943792
summer acclimatization in the short-tailed field vole, microtus agrestis.we investigated the changes that occurred in basal and noradrenaline-induced metabolic rate, body temperature and body mass in short-tailed field voles, microtus agrestis, during exposure to naturally increasing photoperiod and ambient temperature. these parameters were first measured in winter-acclimatized voles (n = 8) and then in the same voles which had been allowed to seasonally acclimatize to photoperiod and ambient temperature (6 months later). noradrenaline induced metabolic rate, basal ...19968810068
experimental demonstration of the antiherbivore effects of silica in grasses: impacts on foliage digestibility and vole growth rates.the impact of plant-based factors on the population dynamics of mammalian herbivores has been the subject of much debate in ecology, but the role of antiherbivore defences in grasses has received relatively little attention. silica has been proposed as the primary defence in grasses and is thought to lead to increased abrasiveness of foliage so deterring feeding, as well as reducing foliage digestibility and herbivore performance. however, at present there is little direct experimental evidence ...200616928631
phytosterols affect endocrinology and metabolism of the field vole (microtus agrestis).phytosterols or plant sterols (ps) enter the ecosystem via pulp mill effluents. they are also consumed by the general population of developed countries in natural remedies and margarines to lower elevated serum cholesterol levels. this study screened the endocrine and enzymatic parameters of the field vole (microtus agrestis) for the effects of subchronic ps exposure at three doses (0, 5, or 50 mg of ps kg(-1) day(-1)). ps at 5 or 50 mg kg(-1) day(-1) decreased the relative liver weight of the v ...200312563026
proliferating cell nuclear antigen (pcna) expression in tooth primordia in the field vole (microtus agrestis, rodentia).cell proliferation in developing tooth germs has been studied particularly using bromodeoxyuridine (brdu) incorporation into growing tooth primordia and by counting and three-dimensional (3d) reconstruction of mitoses in serial sections of developing teeth. pcna has been proposed as an alternative marker of proliferation activity. the aim of our study was to detect immunohistochemically locations of pcna-positive cells in developing tooth germs of microtus agrestis (rodentia). pcna expression co ...200212489149
phylogeography of field voles (microtus agrestis) in eurasia inferred from mitochondrial dna sequences.in a distribution-wide phylogeographic survey of the field vole (microtus agrestis), 75 specimens from 56 localities across eurasia were examined for dna sequence variation along the whole 1140 base pair (bp) mitochondrial (mt) cytochrome b gene. the species is subdivided into three main mtdna phylogeographic groups - western, eastern and southern - with largely allopatric distributions. the western phylogeographical group is found in west and central europe and spread most probably from a glaci ...200212453244
the consequences of acute cold exposure on protein oxidation and proteasome activity in short-tailed field voles, microtus agrestis.during cold exposure, animals upregulate their metabolism and food intake, potentially exposing them to elevated reactive oxygen species (ros) production and oxidative damage. we investigated whether acute cold (7 +/- 3 degrees c) exposure (1, 10, or 100 h duration) affected protein oxidation and proteasome activity, when compared to warm controls (22 +/- 3 degrees c), in a small mammal model, the short-tailed field vole microtus agrestis. protein carbonyls and the chymotrypsin-like proteasome a ...200212106821
[a study of dna depolyploidization and depolytenization of the heterochromatized gonosomal chromatin bodies in the secondary giant trophoblast cells of the field vole microtus rossiaemeridionalis using cytophotometry].a study was made of the distribution of the heterochromatized gonosomal chromatin bodies (gcb) material in the course of nuclear fragmentation of secondary giant trophoblast cells resulting in polykaryocyte formation at the late stage of their differentiation. a simultaneous dna cytophotometry in gcbs and nuclear fragments showed a progressive gcb dna content decrease proportional to that of dna content in nuclear fragments. dna contents in the nuclear fragments corresponded to 2c, 4c and 8c. in ...200516711385
antioxidant enzyme activities, lipid peroxidation, and dna oxidative damage: the effects of short-term voluntary wheel running.we examined the effect of voluntary exercise on antioxidant enzyme activities (catalase, glutathione peroxidase, superoxide dismutase) in skeletal muscle (hind- and forelimb) and heart of a model small mammal species: short-tailed field vole microtus agrestis. in addition, dna oxidation was determined in lymphocytes and hepatocytes using the comet assay and lipid peroxidation estimated in hindlimb muscle by measurement of thiobarbituric-acid-reactive substances. voles (approximately 6 weeks old) ...200212054476
pink-eyed dilution, a coat color mutation in the japanese field vole (microtus montebelli).inheritance of dilute coat color with pink eye in the japanese field vole (microtus montebelli) was investigated by mating of the dilute mutant with a normal agouti vole and a white vole. as the results, it was cleared that an autosomal recessive gene p is responsible for the pink-eyed dilution in m. montebelli.19911915604
bisphenol a affects endocrine physiology and biotransformation enzyme activities of the field vole (microtus agrestis).bisphenol a (bpa), an environmental estrogen, was given subcutaneously for 4 days to 48 field voles at three doses (10, 50, or 250 mg kg(-1) day(-1)). plasma sex steroids, thyroxine, weight-regulatory hormones, and liver biotransformation enzymes were determined. there was no mortality in the control group but the mortality in the bpa-exposed animals was significant. bpa increased the plasma testosterone concentrations at 250 mg bpa kg(-1) day(-1). the plasma ghrelin levels measured from pooled ...200212030774
hypothalamo-neurohypophysial magnocellular neuroendocrine system of field voles after acute heat or cold stress.hypothalamo-neurohypophysial magnocellular neuroendocrine system (h-nh mc nes) of field voles was described in normal conditions and after acute heat or cold stress. 60 mature males of field voles were used for examinations after 2 weeks of adaptation to stable conditions of laboratory keeping. 10 animals were the controls. another group of 25 field voles were subjected to sudden cold of -15 degrees c for 3 hours. the third group of 25 field voles were subjected to sudden heat of +32 degrees c f ...200011712427
behavior and toxicity of antimony in the short-tailed field vole (microtus agrestis).laboratory experiments were undertaken to study uptake and retention of antimony and to investigate whether the elevated organ antimony concentrations found previously in a population of microtus agrestis at a contaminated site could cause harmful effects. antimony trioxide in the diet produced elevated organ concentrations, but even in a 60-day experiment no harmful effects were evident. an equilibrium between uptake and excretion of antimony seemed to be rapidly established and progressive inc ...19912065629
differences in the meiotic pairing behavior of gonosomal heterochromatin between female and male microtus agrestis: implications for the mechanism of heterochromatin amplification on the x and y.it is generally thought that pairing and recombination between the x and y chromosome in eutherian mammals is important for the occurrence of normal meiotic division and the production of functional gametes. microtus agrestis is one of the examples whose giant and heterochromatin-rich sex chromosomes fail to establish a durable association at any stage of the first meiotic division in males. in contrast, in females, synapsis starts in the euchromatic short arm and pairing progresses unidirection ...200011173866
can non-shivering thermogenesis in brown adipose tissue following na injection be quantified by changes in overlying surface temperatures using infrared thermography?we aimed to investigate whether infra red thermography (irt) can be used to measure and quantify non-shivering thermogenesis (nst) in the short-tailed field vole microtus agrestis, by directly comparing it with a standard method, i.e. metabolic response following noradrenaline injection (na). mean skin surface temperature overlying brown adipose tissue (bat) depot was 0.82 degrees c higher than mean surface temperature that did not overly bat. the difference in temperature increased by 1.26 degr ...200111163923
natal dispersal in relation to population density and sex ratio in the field vole, microtus agrestis.in a sample of 240 juvenile field voles 8% of the males and 22% of the females reached sexual maturity within their natal home range. among individuals retrapped as adults, 58% of males and 23% of females had dispersed, i.e. had moved more than one home range diameter. the mean distance moved for males (58.5 m) exceeded that for females (28.6 m). male movement distances were negatively associated with total density, and with density of adult females, but not with male density. female movements w ...199022160104
male short-tailed field voles (microtus agrestis) build better insulated nests than females.nest construction is an extremely widespread behaviour. in small endotherms the nest serves primarily to provide insulation, and thereby retard heat loss of the constructor, or its offspring. in arctic and temperate regions many small mammals build nests to protect themselves from low ambient temperatures. we measured the physical properties of nests built by short-tailed field voles microtus agrestis that were kept in captivity under cold conditions. the most important factor influencing nest i ...199910633563
spatial asynchrony and periodic travelling waves in cyclic populations of field voles.we demonstrate evidence for the presence of travelling waves in a cyclic population of field voles in northern britain by fitting simple, empirical models to spatially referenced time series data. population cycles were broadly synchronous at all sites, but use of mantel correlations suggested a strong spatial pattern along one axis at a projection line 72 degrees from north. we then fitted a generalized additive model to log population density assuming a fixed-form travelling wave in one spatia ...19989744104
distribution of trace element pollutants in a contaminated grassland ecosystem established on metalliferous fluorspar tailings. 2: zinc.concentrations of zinc in vegetation, invertebrates and small mammals in a grassland ecosystem derived from a mine waste vegetation scheme indicated the high concentration of zinc in the original tailings. however, the considerable differences in soil and vegetation zinc concentrations between the tailings and an uncontaminated site were not reflected in the invertebrate and small mammal communities. invertebrate zinc levels and total body concentrations in microtus agrestis l. (field vole) and ...198915092405
distribution of trace element pollutants in a contaminated ecosystem established on metalliferous fluorspar tailings. 3: fluoride.high total soil fluoride (10 000 microg g(-1)) in the metalliferous fluorspar tailings was reflected by elevated concentrations in standing live vegetation (300-1000 microg g(-1)); plant roots (c. 6000 microg g(-1)); plant litter (c. 4000 microg g(-1)); total body concentrations of invertebrates (400-4000 microg g(-1)) and the small mammals microtus agrestis (120-360 microg g(-1)) and sorex araneus (140-250 microg g(-1)). seasonal changes in the standing live vegetation and the availability of s ...198915092395
beta-heterochromatin in mammals: evidence from studies in microtus agrestis based on the extensive accumulation of l1 and non-l1 retroposons in the heterochromatin.the heterochromatin of microtus agrestis contains two retroposons, one l1 and one non-l1, which were cloned and analyzed with respect to their structure and genomic organization. these sequences have accumulated in the heterochromatin and exhibit a complex interspersed organization of relatively recent origin. in contrast, the pericentromeric heterochromatin is composed of simple, repetitive, tandemly organized elements. from the underlying sequences, the dinucleotide frequencies, the sequence o ...19989678352
postnatal development of the masseter muscles in the japanese field vole microtus montebelli, with special attention to differentiation of the fast-twitch oxidative fiber.postnatal development and differentiation of the masseter muscles consisting only of fast-twitch oxidative (fo) fibers in the adult japanese field vole microtus montebelli were studied using histochemical and electron microscopic techniques. the masseter muscles were composed of myotubes and muscle fibers at day 0 (birth day). most muscle cells showed the strong reaction for myosin atpase after both alkaline and acid preincubations. for nadh-dehydrogenase (nadh-dh), small granular diformazan dep ...19979450394
transcriptional activity of constitutive heterochromatin in the mammal microtus agrestis (rodentia, cricetidae).two cytological approaches were applied to the analysis of genetic activity in euchromatin and heterochromatin in the european field vole microtus agrestis. the first is based on the transcriptional activity of prematurely condensed chromosomes, the second on in situ hybridization of labeled cellular rna to metaphase chromosomes. the results show that in cultivated fibroblasts, the transcriptional activity of constitutive heterochromatin is in the same order of magnitude as that of euchromatin; ...19872446895
tooth damage in field voles, wood mice and moles in areas polluted by fluoride from an aluminum reduction plant. 19873317818
effect of nutrition, temperature and photoperiod on the rate of sexual maturation of the field vole (microtus agrestis).weanling male and female field voles were placed in long or short photoperiods, kept at 18 degrees c or 4 degrees c, and fed (ad libitum) diets containing 24%, 16%, 8% and 4% protein, for 6 weeks. animals in the long photoperiod were more sexually mature than were animals in the short photoperiod. temperatures had no effect on females, but did affect males: those kept at 4 degrees c had heavier testes and wider seminiferous tubules than those kept at 18 degrees c. there was little difference bet ...19873298643
circadian activity patterns, photoperiodic responses and population cycles in voles : i. long-term variations in circadian activity patterns.patterns of above-ground activity were recorded in two free-ranging populations of microtus agrestis (l.) and one population of m. arvalis (pall.) over several years by means of passage counters. long-term variations of the circadian patterns were observed, but did not repeat themselves in a 12-month cycle. variations in all three populations could be described by a sinusoidal function of an 18-month period. maxima and minima of the sine-function were connected to distinct photoperiods (equinoxe ...198728312229
pattern of x-y chromosome pairing in the japanese field vole, microtus montebelli.pairing of x and y chromosomes at meiotic prophase in males of microtus montebelli was analyzed. the sex chromosomes form a synaptonemal complex at pachytene and end-to-end association at diakinesis-metaphase i in two species of the genus microtus (m. montebelli and m. oeconomus) only, while they do not pair at all in the other species of this genus that have been studied so far. these data confirm that m. montebelli and m. oeconomus are very closely related in their origin. it is suggested that ...19979449794
basal metabolic rate in relation to body composition and daily energy expenditure in the field vole, microtus agrestis.basal metabolic rate in the field vole (microtus agrestis) was studied in relation to body composition and daily energy expenditure in the field. daily energy expenditure was measured by means of doubly labelled water (d2 18o). in the same individuals, basal metabolic rate was subsequently derived from o2 consumption in an open-circuit system in the laboratory. body composition was obtained by dissecting the animals and determining fresh, dry, and lean dry mass of different organs. daily energy ...20139231410
fluoride-induced lesions in the teeth of the short-tailed field vole (microtus agrestis): a description of the dental pathology.the effect of fluoride on the appearance of the teeth of the short-tailed field vole, microtus agrestis, was investigated in both wild animals collected from field sites affected by different levels of industrial fluoride contamination and laboratory-reared animals consuming experimental grass diets of known fluoride concentration or with known fluoride concentrations in drinking water. the extent and severity of lesions on the surface and structure of both incisors and molars are described as s ...19979097466
a contact zone with noncoincident clines for sex-specific markers in the field vole (microtus agrestis).a field vole (microtus agrestis) population characterized by unique mitochondrial dna (mtdna) and y chromosome markers occurs in southwest sweden. a contact zone between this lund (lu) population and a standard (st) population was examined with two sex-specific genetic markers. the field vole mtdna and y chromosome clines display a remarkable lack of coincidence, rarely observed in contact zones. the cline width for both markers is about 50 km, but the two clines are displaced from each other: t ...199728568796
susceptibility to vole attacks due to bark phenols and terpenes inpinus contorta provenances introduced into sweden.seedlings of north americanpinus contorta introduced to sweden and finland are severely gnawed by voles, e.g.,microtus agrestis. the level of damage varies between provenances. chemical analyses of various phenolic compounds, monoterpenes, and resin acids of different provenances and of damaged and undamaged stems showed that some phenolic substances in the bark increased after damage without deterring the animals, that monoterpene differences between provenances were not related to vole damage, ...198624305834
mitochondrial dna variation in the field vole (microtus agrestis): regional population structure and colonization history.restriction fragment length polymorphism analysis of mitochondrial dna (mtdna) was used to examine the genetic structure among field voles (microtus agrestis) from southern and central sweden. a total of 57 haplotypes was identified in 158 voles from 60 localities. overall mtdna diversity was high, but both haplotype and nucleotide diversity exhibited pronounced geographic heterogeneity. phylogenetic analyses revealed a shallow tree with seven primary mtdna lineages separated by sequence diverge ...199628565579
effect of hypotaurine on in vitro fertilization and production of term offspring from in vitro-fertilized ova of the japanese field vole, microtus montebelli.the present study was proposed to establish new in vitro fertilization (ivf)-embryo transfer techniques for wild mammals. we demonstrated that ivf of the japanese field vole, microtus montebelli, is improved by hypotaurine, and that ivf vole embryos can develop to normal offspring after transfer to recipient females. the rate of ivf was significantly increased when 0.1 or 1 mm of hypotaurine was added during sperm preincubation and fertilization (p < 0.05). preincubation of spermatozoa with 1 mm ...19968835384
postnatal development of intestinal villi in the field vole (microtus montebelli): a scanning electron microscopic study. 19836358986
pineal influences hypothalamic gn-rh content in the vole, microtus agrestis. 19836339718
[role of enzymes in the nonspecific cutaneous glands in the marking behavior of field voles of the clethrionomys species]. 19968664841
evolution of the gonosomal heterochromatin of microtus agrestis: rapid amplification of a large, multimeric, repeat unit containing a 3.0-kb (gata)11-positive, middle repetitive element.the sex chromosomes of microtus agrestis are extremely large due to the accumulation of constitutive heterochromatin. we have cloned and characterized a 2,999-bp (gata)n-positive sequence, following haeiii digestion, that is confined to the noncentromeric heterochromatin of the x chromosome. the cloned element exhibits an accumulation of certain oligomers, which are scattered throughout its entire length, and several copies of chi-related sequence motifs, which are thought to be implicated in re ...19968697802
[occurrence of white japanese field vole (microtus montebelli) in the laboratory].some field voles with a white coat color were found in the breeding process in the laboratory, originated from a wild population captured in the riverside of the arakawa in okegawa, saitama prefecture in japan. they had been raised in a room and fed with pelleted feed for herbivore. an attempt was made to analyze their breeding records and mode of inheritance for the white coat color. as a result, the average litter size was 3.80 +/- 1.52, and the age of the first birth was 121 +/- 46.8 in days. ...19826762967
[brain deformation caused by hyperplasia molar teeth (macrodonts) in the japanese field vole (microtus montebelli)].protrusion of hyperplastic upper molar teeth (macrodonts) into the cranial cavity was observed in the japanese field vole. protrusions of the upper molars occurred on both sides, but were large on the left than on the right. the teeth invaded the cranial cavity and brain parenchyma. large concavities on the ventral side of the brain were interposed between the lateral olfactory tract and the optic tract. invation by one macrodont reached the basal nuclei, hypothalamic and thalamic nuclei. the br ...19957498346
in vitro cultivation of trypanosoma acomys: production of insect stages and bloodstream forms.when trypanosoma acomys bloodstream forms were cultivated at 37 degrees c in schneider's drosophila medium supplemented with 20% (v/v) heat-inactivated foetal calf serum (fcs), with microtus agrestis embryonic fibroblasts in rpmi 1640 medium supplemented with 20% fcs or in baltz's medium supplemented with 10% fcs, the parasites transformed and largely remained as epimastigotes. epimastigotes were also usually the commonest stage observed when the parasites were co-cultivated with a mosquito cell ...19958570583
age-accumulation of fluoride in an experimental population of short-tailed field voles (microtus agrestis l.).this paper reports on the effects of a diet of vegetation contaminated by atmospheric fluorides upon the growth and age-accumulation of fluoride by a laboratory-maintained population of the short-tailed field vole, m. agrestis, a wild herbivore. offspring of the voles fed the contaminated diet generally had lower growth rates and body weights during infancy and early adulthood than those fed a reference diet. the concentration and total fluoride burden of the femur were significantly higher in v ...19947939626
morphological and histological studies on the gastric mucosa on the japanese field vole, microtus montebelli montebelli. 19817045473
fluoride accumulation and toxicity in wild small mammals.populations of two species of small mammal, the field vole (microtus agrestis l.) and the bank vole (clethrionomys glareolus l.), inhabiting grasslands contaminated by industrial sources of fluoride were examined for fluoride concentrations in skeletal tissue and for morphological changes in the teeth. concentrations of fluoride in teeth and bones were higher for c. glareolus than for m. agrestis at the chemical works and smelter sites. severe dental lesions were recorded on the incisor and mola ...199415091672
long photophase is not a sufficient stimulus to reduce thermogenic capacity in winter-acclimatized short-tailed field voles (microtus agrestis) during long-term cold acclimation.the thermogenic capacity of brown adipose tissue in winter- and summer-acclimatized short-tailed field voles (microtus agrestis) was investigated by examining changes in mass of brown adipose tissue, the ratio of white adipose tissue to brown adipose tissue, the concentration of the uncoupling protein (thermogenin) in whole depots (micrograms) and in mitochondrial mass (micrograms.mg-1) and the activity of cytochrome c oxidase in the depots (mmol.min-1). the concentration of thermogenin in winte ...19948056882
topographical relationships of synaptic ribbons in the pineal system of the vole (microtus agrestis).in the pineal system of the vole (microtus agrestis) both the superficial and the deep pineal exhibit a high percentage of synaptic ribbons lying in intimate contact with the cell membrane of the pinealocytes. at the sites of contact, densities resembling the presynaptic dense projections of synapses are arranged between the ribbons and the cell membrane. opposite the sites of contact various elements were found. the quantitative estimation revealed that in the superficial pineal about 40% and i ...19817023277
effects of age on photo-induced testicular regression, recrudescence, and refractoriness in the short-tailed field vole microtus agrestis. 19806998517
parental investment related to social systems in microtines.laboratory offspring of wild-caught voles clethrionomys glareolus and microtus agrestis, bred for 1 year under constant conditions, were examined with regard to sex ratios and weights at weaning and at 2 months of age. c. glareolus exhibits female territoriality and m. agrestis male territoriality in summer. the adults die away in late summer-autumn. early-summer young mature in the year of birth but late-summer young do not reach maturity until the following year. c. glareolus young showed a ma ...199228312884
dynamics and trophic interactions of small rodents: landscape or regional effects on spatial variation?geographically varying rodent dynamics may be due to specific landscape effects or to regional variation. two common vole species (clethrionomys glareolus and microtus agrestis), their main predators and their impact on some important food items were monitored in sweden on forest clearcuts in two different landscape types, situated in two different regions with different climatic conditions. censuses, with 10-16 clearcuts in each landscape and both landscapes in the two regions, were designed to ...200228547149
acceleration of ovarian follicle maturation of female caused by male in microtus agrestis and clethrionomys glareolus. 19807004917
feulgen-dna changes in the germ cells of the male vole (microtus agrestis) during their development.consistent with changes in ploidy during germ cell maturation, the quantity of feulgen dna in round spermatids of voles is approximately a quarter of that in primary spermatocytes. the amount increases slightly in elongated spermatids, and then declines in spermatozoa from the testis, epididymis and vas deferens, below the level of round spermatids. simultaneously nuclear area decreases so that in spermatozoa it is about one tenth that of primary spermatocytes. the rise in feulgen dna in elongat ...19806760273
evidence for a coitally induced 'mnemonic' involved in luteal function in the vole (microtus agrestis).the development of luteal function in the vole is dependent on a neuroendocrine reflex which is initially activated by mating. bromocriptine was used to destroy the cl initially induced by mating and fresh cl were induced by hormone treatment. the fate of such newly formed cl suggested that the luteotrophic effect of mating continued for about 10 days after mating, despite the destruction of the original mating-induced cl. the luteotrophic effect of mating therefore seems to be 'remembered'. a s ...1979390136
pregnancy blockage and the memory of the stud male in the vole (microtus agrestis).when female voles were allowed contact with the stud male for only 1 h at the time of mating, 55% exhibited pregnancy failure when exposed to a strange male 48 h later. when females were made psuedopregnant by hormone treatment and vaginal stimulation (i.e. no stud male involved), 87% exhibited luteal failure when exposed to a strange male. it is suggested that the characteristics of the stud male are rapidly imprinted upon the female at the time of mating and that this imprinting is important i ...1979390135
changes in individual quality during a 3-year population cycle of voles.in small mammal populations with multiannual oscillations in density, the occurrence of large individuals in the peak phase (the "chitty effect") is a typical feature, but mechanisms behind this phenomenon have remained unclear. we analysed long-term data sets collected in western finland between 1984 and 1992 to: (1) find out how the body size and body condition of voles (microtus agrestis, m. rossiaemeridionalis, clethrionomys glareolus) and shrews (sorex araneus) was associated with the 3-yea ...200228547147
hazardous exposure of ground-living small mammals to cadmium and lead in contaminated terrestrial ecosystems.the dietary exposure to cadmium and lead of two ground-living species of small mammals, i.e., shrews sorex araneus (insectivora) and voles microtus agrestis (rodentia), was investigated and related to metal loads in target organs (kidneys and liver). the study was done in two natural areas polluted with cadmium and lead originating from urban and industrial metal sources. the average intake of cadmium by the herbivorous voles varied between 0.1 and 0.4 micrograms/g/day and of lead between 2 and ...19912015002
[morphology and behavior of the sex chromosomes in meiosis in four vole species of the genus microtus].morphology and behaviour of the x and y chromosomes of four species of genus microtus were studied at pachytene, metaphase i and meiotic metaphase. the x chromosomes of the species varied with respect to their size and location of heterochromatic blocks. the axes of x and y chromosomes of these species as well as microtus agrestis never formed true synaptonemal complexes at any sub-stage of the pachytene. they approached each other at the start of the pachytene throughout to metaphase i, getting ...19911773934
adult philopatry and dispersal in the field vol microtus agrestis.using mark-recapture data, we related the movements of adult field voles to population density, sex ratio and population growth. dispersal movements (defined as distances larger than 1 home range diameter) were few in both sexes; 4 out of 197 (2.0%) in males and 8 of 316 (2.5%) in females. the distance moved between sequential trapping periods was similar for males and females; the mean being 10.2 m and 9.0 m respectively. both males and females moved larger distances during the breeding season ...199128313195
spatial dynamics in fluctuating vole populations.patterns and consistency of distribution, spatial and temporal components, and the extent of spatial density-dependence were compared between semi-cyclic and cyclic populations of the vole species clethrionomys glareolus and microtus agrestis in south-central and north sweden. cyclic populations were less clumped and only c. glareolus showed a consistency in distribution between years. spatial variation contributed little to the distributions in cyclic populations while the spatial and temporal ...199028312557
5-azadeoxycytidine induced undercondensation in the giant x chromosomes of microtus agrestis.fibroblasts of female microtus agrestis were treated with 5-azadeoxycytidine (5-aza-dcyd) at a final concentration of 10(-5) m during the last 2 h of culture. this cytidine analogue induces distinct undercondensation of the constitutive heterochromatin in the giant x chromosomes. the undercondensed heterochromatic thread exhibits longitudinal segmentation reminiscent of a chromomere pattern. in the late-replicating x chromosome, 5-aza-dcyd also inhibits condensation of the genetically inactivate ...19892476282
distribution of trace element pollutants in a contaminated grassland ecosystem established on metalliferous fluorspar tailings. 1: lead.concentrations of lead in vegetation, invertebrates and small mammals in a grassland ecosystem evolved from a mine waste revegetation scheme indicated the high concentration of lead in the original tailings. lead levels in invertebrates reflected dietary concentrations and feeding strategy, a pattern also true of the indigenous small mammals. total body and tissue concentrations of lead in the herbivorous microtus agrestis l. (field vole) and insectivorous sorex araneus l. (common shrew) were si ...198915092440
the behavior during pachynema of a normal and an inverted y chromosome in microtus agrestis.the pachytene behavior of the chromosomes of microtus agrestis (l.) (rodentia, arvicolidae) males carrying either the standard, or the pericentrically inverted lund y chromosome have been examined by electron microscopy of microspread spermatocytes. there is no synapsis between the x and either the standard or the lund y chromosomes during any substage of pachynema. since synapsis is generally considered a prerequisite for crossing over, there appears to be no opportunity for crossover or chiasm ...19892698871
postnatal development of the stomach in the japanese field vole, microtus montebelli. 19883052170
comparison of the gonadal response of wild and laboratory field voles (microtus agrestis) to different photoperiods.weanling male and female field voles from laboratory stock and from the f1 generation of wild-caught animals were placed in a long (16l:8d) or short (6l:18d) photoperiod for 28 or 56 days. both types of field vole showed the well-established effect of photoperiod upon sexual maturation, with animals in the long photoperiod having larger and more active gonads than animals in the short photoperiod. after 28 and 56 days laboratory stock females were more mature, sexually, and had a higher growth r ...19873546683
5-aza-c-induced changes in the time of replication of the x chromosomes of microtus agrestis are followed by non-random reversion to a late pattern of replication.treatment with 5-azacytidine (5-aza-c) causes an advance in the time of replication and enhances the dnase-i sensitivity of the inactive x chromosome in gerbillus gerbilllus fibroblasts. we found that these changes were not stably inherited and upon removal of the drug the cells reverted to the original state of one active and one inactive x chromosome. in order to determine whether this reversion was random, we used a cell line of female microtus agrestis fibroblasts in which the two x chromoso ...19872438098
demonstration of an odorous intramale primer effect in short-tailed vole,microtus agrestis l.anal (proctodeal) glands of malemicrotus agrestis housed in social isolation undergo severe atrophy. their weight and volume is significantly lower than those of the stock control males. the atrophied glands can be revived by subjecting deprived voles to various social odors. atrophied glands of isolated males do not respond to the odors of male and female urine, voided feces of females, and unvoided feces of males. atrophied anal glands of males exposed to voided male feces (which have passed t ...198624306670
effect of male presence and of photoperiod on the sexual maturation of the field vole (microtus agrestis).the effect of mature males on the sexual development of young female and male field voles, reared in either long (stimulating) or short (inhibiting) photoperiods, was examined. females reared in the presence of a mature male had a more advanced state of sexual maturation (as indicated by uterine weight) than did females reared in isolation from males, in long and short photoperiods (p less than 0.01). no interaction between photoperiod and male presence was found. augmented uterine growth occurr ...19863531507
gradients in density variations of small rodents: the importance of latitude and snow cover.microtine rodents are known to show extreme population variations (cycles) but non-cyclic populations have also been recognized during recent years. the cyclic populations have been widely thought to be regulated by intrinsic mechanisms. however, such predictions for cyclic populations are usually not applicable to non-cyclic ones and extrinsic factors may have to be included in any explanation.a hypothesis that the degree of fluctuations in small rodent numbers is related to the sustainable num ...198528311574
effect of mating on the metabolic activity of the brain and pituitary gland assessed by [14c]2-deoxyglucose in a reflex ovulator, the vole (microtus agrestis).the neural pathways involved in reflex ovulation in the vole (microtus agrestis) have been investigated with the [14c]2-deoxyglucose (2-dg) method. female voles were injected i.p. with 2-dg and either not mated, sham-mated (mounted by males by vagina was taped) or mated for a period of 45 min after the injection, after which the animals were decapitated. the brain was processed for autoradiography and the relative metabolic activities (rma) of selected areas of the brain and pituitary gland were ...19846388729
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