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Long-term monitoring is critical to determine the stability and sustainability of wildlife populations, and if change has occurred, why. We have followed population density changes in the small mammal community in the boreal forest of the southern Yukon for 46 years with density estimates by live trapping on 3-5 unmanipulated grids in spring and autumn. This community consists of 10 species and was responsible for 9% of the energy flow in the herbivore component of this ecosystem from 1986 to 1996, but this increased to 38% from 2003 to 2014. Small mammals, although small in size, are large in the transfer of energy from plants to predators and decomposers. Four species form the bulk of the biomass. There was a shift in the dominant species from the 1970s to the 2000s, with Myodes rutilus increasing in relative abundance by 22% and Peromyscus maniculatus decreasing by 22%. From 2007 to 2018, Myodes comprised 63% of the catch, Peromyscus 20%, and Microtus species 17%. Possible causes of these changes involve climate change, which is increasing primary production in this boreal forest, and an associated increase in the abundance of 3 rodent predators, marten (Martes americana), ermine (Mustela ermine) and coyotes (Canis latrans). Following and understanding these and potential future changes will require long-term monitoring studies on a large scale to measure metapopulation dynamics. The small mammal community in northern Canada is being affected by climate change and cannot remain stable. Changes will be critically dependent on food-web interactions that are species-specific., (© 2019 The Authors. Integrative Zoology published by International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.)

The classification of rodent species can be challenging due to high morphological similarities observed among them. This problem is further increased in palaeontological systematics, where classification is traditionally based on the molar morphology. The subfamily Arvicolinae (Rodentia, Mammalia) is one of these rodent groups, whose classification being important for biostratigraphic and climatic studies of the Quaternary period is challenging. We present an application developed using the MatLab informatic algorithm, designed to classify the Arvicolinae species using Geometric Morphometrics (GMM) analyses of the first lower molar. Moreover, the application includes an option to automatically obtain the linear measurements that are commonly used for the identification of these species. This method shows a high degree of accuracy in the species classification, which is expected to increase as the reference database is further developed. This application can serve as an alternative tool for the classification of specimens with unclear morphologies. It can also be used to reduce the time required to manually obtain the linear indices necessary for their classification. [ABSTRACT FROM AUTHOR]

Forest understory complexity is important for many species, from large herbivores such as deer to small mammals such as mice and voles. For species that utilize the forest understory on a very small scale, it is often impractical to conduct correspondingly fine‐grained manual surveys of the understory, and thus few studies consider this small‐scale variation in understory complexity and instead work with average values on a larger scale. We explored the use of a mobile laser scanning derived understory complexity measure—understory roughness—to predict the capture probability of two representative small mammal species, the yellow‐necked mouse (Apodemus flavicollis) and the bank vole (Clethrionomys glareolus). We found a positive relationship between capture probability and understory roughness for both bank voles and yellow‐necked mice. Our results suggest that mobile laser scanning is a promising technology for measuring understory complexity in an ecologically meaningful way. [ABSTRACT FROM AUTHOR]

Patterns of introgression of several genetic markers across the hybrid zone between allied species of the common vole Microtus arvalis s. str. and M. obscurus was studied in four of its sections: in northwest Nizhny Novgorod oblast, east Vladimir and southwest Nizhny Novgorod oblasts, south Lipetsk oblast, and northwest Voronezh oblast. Analysis of the clinal variability for three molecular genetic markers (cytb, tp53, SMCY11) and for karyotypes showed a structural similarity between the "Vladimir–Nizhny Novgorod," "Nizhny Novgorod," and "Voronezh" sections. The maximum width was shown for the cytb cline; the minimum width was shown for the SMCY11 cline; the tp53 cline and chromosomal cline occupy an intermediate position for this parameter. Furthermore, in these transects, the center of the cline for the cytb is shifted southeastward (into the distribution range of M. obscurus) from the centers of three other clines. The revealed asymmetric introgression of mitochondrial genome from M. arvalis to M. obscurus may be explained by the fact that the hybrid zone was formed as a result of invasion of M. obscurus into the range of M. arvalis. The "Lipetsk" transect differs from the three above-mentioned transects in very narrow clines with nearly coinciding centers. Such characteristics of the "Lipetsk" transect are obviously caused by localization of the hybrid zone in this section along Voronezh River. The obtained results led us to suppose that the structure of the studied hybrid zone is determined mainly by coincidence (or noncoincidence) of its center with local physical barriers. [ABSTRACT FROM AUTHOR]

The construction of regional biochronological scales for the Pleistocene based on remains of small mammals is a systematic and successive process of accumulation of informative data with their subsequent presentation in the form of schemes and tables. The geological and palaeontological characteristics of reference sections are presented in detail. Faunal assemblages and developmental phases in associations of small mammals in the south of Eastern Europe are described based on the taxonomic composition of Pleistocene micromammal fauna. Ortho- and parastratigraphic taxa are identified and phylogenetic trees are constructed based on modifications of morphological traits in the evolution of separate species. A macroevolutionary biochronological scale has been compiled using several types of biochronozones. A phenozone-based microevolutionary biochronological scale has been established for the Quaternary of the south of Eastern Europe. These scales can be used to subdivide Quaternary deposits of this region by identifying biostratigraphic units and correlating them on local and regional scales. [ABSTRACT FROM AUTHOR]

Numerous small mammal localities assigned to the beginning of the Late Middle Pleistocene (Holstein, Likhvin, Hoxne Interglacial) were discovered in Europe during the last years. The stratigraphical position of a number of these faunas and the regional differences are discussed in the paper. The new Likhvin small mammal locality Rybnaya Sloboda (Lower Kama basin, Volga basin, Russia) is the easternmost site of this age in Europe. The rich fauna was discovered in fluvial deposits of the 3rd terrace (III) of the Kama River; sediments that are covered by loess deposits with a series of paleosols. The Rybnaya Sloboda fauna includes 16 species of insectivores, lagomorphs and rodents. Remains of the archaic water vole Arvicola cantianus and the Middle Pleistocene steppe lemming Lagurus transiens dominate the fossils assemblage. The evolutional level of the Arvicolinae remains permits the assignment to the Gun'kovian small mammal assemblage and a correlation with the Likhvin Interglacial (MIS 11) (∼424–374 ka BP). The ecological features of the small mammal assemblage indicate a forest-steppe landscape in the lower Kama basin during MIS 11. The comparison with, and the analysis of numerous European Likhvin (= Holsteinian, = Hoxnian) small mammal faunas indicate a geographical biozonation that shows similarities with the biozonation reconstructed for the Eemian (= Mikulino, MIS 5e) Interglacial. [ABSTRACT FROM AUTHOR]

While many studies have characterized small mammals of the southern and central Great Plains (USA), far fewer have documented small mammals of the northern Great Plains which differ dramatically in plant structure and composition. We examined the presence and distribution of small mammals captured at a salinity-affected grassland in northeastern North Dakota (2018–2021). We captured 12 species from 8 genera including Microtus pennsylvanicus (n = 724), Peromyscus (maniculatus) sonoriensis (n = 114), Sorex cinereus (n = 54), and Zapus hudsonius (n = 43). We evaluated the extent to which these species varied with plant and environmental characteristics. M. pennsylvanicus was positively associated with plant cover and soil moisture and P. (maniculatus) sonoriensis was positively associated with forb cover and negatively associated with litter and elevation. Z. hudsonius was negatively associated with forb cover and soil moisture and S. cinereus was positively associated with cover and negatively associated with salinity. These species associated with their environments differently than their more southern counterparts and reinforce the notion that not all areas, even in relatively intact grasslands, are available to all species. Future studies are needed to further examine more infrequently captured species, including a Sorex hoyi, an Onychomys leucogaster, and eight Myodes gapperi in this region. [ABSTRACT FROM AUTHOR]

A correction notice was issued for a study on the detection of Alpha- and Betacoronaviruses in small mammals in Western Yunnan Province, China. The correction involved updating the species name "Short-tailed shrew" to "Chinese mole shrew" in Table 2 of the publication. The scientific conclusions of the study were deemed unaffected by this correction, which was approved by the Academic Editor. [Extracted from the article]

We looked at lectotype designations by Baranova and Gromov from among syntypes in the Mammal Collection of the Zoological Institute of the Russian Academy of Sciences (ZIN) in St. Petersburg, Russia. We identified 20 lectotypifications, published in 2003, which do not accord to Articles 74.7.3 and/or 74.1.3 of the Code and are therefore invalid. Particularly instructive is the case of Lemmus obensis bungei Vinogradov, B.S. (1924). Two new interesting lemmings from Siberia. Ann. Mag. Nat. Hist. 9: 186–188, since its syntypes originated from two allopatric phylogenetic lineages which were classified as distinct nominal taxa. Because the act of lectotypification by Baranova and Gromov does not contain an express statement of deliberate designation as is requested by the amended Article 74.7.3 of the Code, their designation is not valid. To secure the nomenclatural stability of Siberian lemmings we designate voucher ZIN 11,025 (skin and skull from Sagastyr Island) as the lectotype of Lemmus obensis bungei. The name bungei thus defined is a junior synonym of Lemmus lemmus sibiricus (Kerr, R. (1792). The animal kingdom [...] of the celebrated Sir Charles Linnæus. Class I. Mammalia, J. Murray, London) with a range at the shores of the Arctic Ocean, between the Northern Dvina and Lena Rivers. We furthermore provide a list of all invalid lectotypifications of hamsters (Cricetinae) and voles (Arvicolinae) based on ZIN syntypes. [ABSTRACT FROM AUTHOR]

Nonhomologous chromosome interactions take place in both somatic and meiotic cells. Prior to this study, we had discovered special contacts through the SYCP3 (synaptonemal complex protein 3) filament between the short arms of nonhomologous acrocentrics at the pachytene stage in the Alay mole vole, and these contacts demonstrate several patterns from proximity to the complete fusion stage. Here, we investigated the nonhomologous chromosome contacts in meiotic prophase I. It turned out that such contacts do not introduce changes into the classic distribution of DNA double-strand breaks. It is noteworthy that not all meiotic contacts were localized in the H3k9me3-positive heterochromatic environment. Both in the mid zygotene and in the early–mid diplotene, three types of contacts (proximity, touching, and anchoring/tethering) were observed, whereas fusion seems to be characteristic only for pachytene. The number of contacts in the mid pachytene is significantly higher than that in the zygotene, and the distance between centromeres in nonhomologous contacts is also the smallest in mid pachytene for all types of contacts. Thus, this work provides a new insight into the behavior of meiotic contacts during prophase I and points to avenues of further research. [ABSTRACT FROM AUTHOR]

Generalist predators using small mammals as their primary prey are suggested to shift hunting alternative prey such as bird nests, when small mammals are in short supply (the alternative prey hypothesis, APH). Nest survival and survival of young individuals should be positively linked to small mammal abundance and negatively linked to predator abundance, but little information exists from survival of chicks, especially until recruitment. We test these predictions of the APH using 13 years (2002–2014) of life history data from a ground nesting shorebird breeding on coastal meadows. We use small mammal abundance in the previous autumn as a proxy for spring predator abundance, mainly of mammalian predators. We examine whether small mammal abundance in the spring and previous autumn explain annual variation in nest survival from depredation and local recruitment of the southern dunlin Calidris alpina schinzii. As predicted by the APH, survival from nest predation was positively linked to spring small mammal abundance and negatively linked to autumn small mammal abundance. Importantly, local recruitment showed opposite responses. This counterintuitive result may be explained by density‐dependent survival. When nest depredation rates are low, predators may show stronger numerical and functional responses to high shorebird chick abundance on coastal meadows, whereas in years of high nest depredation, few hatching chicks lure fewer predators. The opposite effects on nest and local recruitment demonstrate the diverse mechanisms by which population size variation in primary prey can affect dynamics of alternative prey populations. [ABSTRACT FROM AUTHOR]

The complete mitochondrial DNA (mitogenome) sequences of Chionomys nivalis and C. roberti were first presented as reference mitogenomes by the current study using Long-Range PCR and Next-Generation Sequencing. The structure and organization of the circular mitogenomes were similar for each species. Each mitogenome included 22 tRNA genes, two rRNA genes, 13 protein-coding genes (PCGs), a control region (D-loop), and an origin of the light-strand region (OL), with the mitogenome lengths of 16.293 for C. nivalis and 16.300 for C. roberti. Phylogenetic analyses based on whole mitogenomes sequences allowed us to see better the relative position of the Chionomys within Arvicolinae. According to this, Chionomys was in a close phylogenetic relationship with Microtus rather than Arvicola. Contrary to the results of past studies, the relative positions of the species within Chionomys varied in the cytochrome b sequence-based phylogenetic analyses. Additionally, the presence of 10 genetic lineages determined by previous works within C. nivalis was approved. Among them, the Central Taurus lineage genetically was the lineage most distant from others. On the other hand, Turkish C. roberti specimens were clustered with the Transcaucasian specimens (Datvisi- Georgia and Alania-North Ossetia-Russia) splitting from other GenBank specimens of Russia and Georgia. Divergence-time analyses demonstrated that the first appearance of Arvicolinae dates back to the Early Pliocene (4.96 mya, 95% HPD: 4.09–5.82, BPP: 1), compatible with the past findings. Also, it was detected that the split of Arvicola / Chionomys + Microtus took place at the beginning of the Quaternary period (2.35 mya, 95% HPD: 1.97–2.75, BPP: 0.98). This corresponded to the Early Pleistocene divergence (approximately 2.4 mya) of these three genera suggested by the fossil record. In addition to this, molecular dating analyses demonstrated that the divergence between C. nivalis and C. roberti occurred in the Middle Pleistocene (1.06 mya, 95% HPD: 0.87–1.25, BPP: 1). Further studies using other molecular markers are needed to make definite judgments on the taxonomy and evolution of Chionomys. [ABSTRACT FROM AUTHOR]

1. The study of animals in nature is essential for developing an ecologically valid understanding of behaviour. Small mammals, however, are often fossorial and exceedingly difficult to monitor in the wild. This limits both the taxonomic scope of field observation, and excludes species that are powerful models for the study of behavioural mechanisms. 2. Here, we implement an automated radiotelemetry system (ARTS) designed to track small fossorial mammals. Our ARTS uses an isotropic antenna array coupled with broadband receivers. We characterized transmission at our study site and tested the ARTS’s ability to track 48 prairie voles. 3. We compared position estimates from nonlinear least squares, nonparametric and Bayesian trilateration methods and found Bayesian trilateration to have the smallest error. To examine the ability of the system to track biologically significant behaviour, we used ARTS data to investigate circadian rhythms of freely behaving prairie voles. We used Lomb–Scargle analysis to estimate periodic patterns from irregularly sampled time series. Prairie voles demonstrated circadian and ultradian movement. 4. This ARTS offers a new tool to observe rodent behaviour at time-scales and in environments that have not been previously possible, such as investigating social and spatial behaviours on the scale of minutes, hours and days in natural environments. [ABSTRACT FROM AUTHOR]

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The diet of an individual is a result of the availability of dietary items and the individual's foraging skills and preferences. Behavioural differences may thus influence diet variation, but the evolvability of diet choice through behavioural evolution has not been studied. We used experimental evolution combined with a field enclosure experiment to test whether behavioural selection leads to dietary divergence. We analysed the individual dietary niche via stable isotope ratios of nitrogen (δ15N) and carbon (δ13C) in the hair of an omnivorous mammal, the bank vole, from four lines selected for predatory behaviour and four unselected control lines. Predatory voles had higher hair δ15N values than control voles, supporting our hypothesis that predatory voles would consume a higher trophic level diet (more animal versus plant foods). This difference was significant in the early but not the late summer season. The δ13C values also indicated a seasonal change in the consumed plant matter and a difference in food sources among selection lines in the early summer. These results imply that environmental factors interact with evolved behavioural tendencies to determine dietary niche heterogeneity. Behavioural selection thus has potential to contribute to the evolution of diet choice and ultimately the species' ecological niche breadth. [ABSTRACT FROM AUTHOR]

The effects of conspecific densities on dispersal have been well documented. However, while positive and negative density-dependent dispersal based on conspecific densities often are shown to be the result of intraspecific competition or facilitation, respectively, the effects of heterospecific densities on dispersal have been examined far less frequently. This gap in knowledge warrants investigation given the potential for the analogous processes of interspecific competition and heterospecific attraction to influence dispersal patterns and behavior. Here we use a long-term live-trapping study of deer mouse (Peromyscus maniculatus), eastern chipmunk (Tamias striatus), red-backed vole (Myodes gapperi), and jumping mice (Napaeozapus insignis and Zapus hudsonius) to examine the effects of variation in conspecific and heterospecific abundances on dispersal frequency. In terms of conspecific abundance, jumping mice were more likely to disperse from areas with fewer conspecifics, while red-backed voles and chipmunks did not respond to variation in conspecific abundances in their dispersal frequencies. While there were no statistically significant effects of variation in heterospecific abundances on dispersal frequency, some effect sizes for heterospecific abundance effects on dispersal met or exceeded those of conspecific abundances. Conspecific abundances clearly can affect dispersal by some species in this system, but the effects of heterospecific abundances on dispersal frequency are less clear. Based on effect sizes, it appears that there may be potential for heterospecific effects on dispersal by some species in the community, although the strength and causes of these relationships remain unclear. [ABSTRACT FROM AUTHOR]

On the basis of a study of our own and published data on voles from the shores of Lake Evoron (n = 8) and the Amgun River (n = 8) in the Evoron-Chukchagir lowland, as well as individuals from laboratory breeding, new data on karyotypic variation (2n = 38–41, NF = 54–59), chromosomal transformations, and their combinations in the karyotype are presented. The numbering of chromosomes in the Evoron vole karyotype using differential (GTG) staining methods made it possible to identify pairs of chromosomes involved in various chromosomal rearrangements and to number the original pairs for the pairs formed from them by chromosome fusion. The tandem telomere-telomere (TTel) fusions of biarmed chromosomes form a large submetacentric element Mev1/4M; telomere-centromere fusion (TCen) as a result of inactivation of the centromere in one of the acrocentric pairs forms either an acrocentric (Mev17/18A) or metacentric element (Mev17/18M), and the Robertsonian translocation of the same pairs forms a metacentric element (Mev17/18M). The variability of the centromere position in two pairs of autosomes (Mev8 and Mev14) is also shown. The revealed rearrangements made it possible to describe twelve variants of the karyotype: two with 2n = 41, six with 2n = 40, three with 2n = 39, and one with 2n = 38. It is proposed that the voles of the Evoron-Chukchagir lowland be assigned to the "еvoron" chromosome race, and the other voles be assigned to the "argi" race. Prolific offspring from the individuals with TTel fusion in the karyotype and a high percentage of this rearrangement in individuals from natural sample sets indicates the absence of a harmful effect on the viability of voles. [ABSTRACT FROM AUTHOR]

The analysis of all data on the number and distribution of small mammals in Western Siberia over the past 120 years has established that 20 out of 28 species recorded in the northern taiga make up their communities. A similar structure of dominance is generally preserved in the small mammal communities of the northern taiga. The main dominant species, northern red-backed vole, Laxmann's shrew, and the common shrew, predominate almost everywhere. The other six codominant species (Eurasian pygmy shrew and tundra shrew and voles: root vole, common European field vole, European bank vole, and gray red-backed vole) dominate only in certain areas. The remaining 11 species, which are both widely and narrowly distributed, make up a small part of the communities. The increase in the species richness of communities to the east (from 15 to 19 species) is determined by the increase in the number of Siberian species. In general, in the studied area of the northern taiga, the largest contribution to small mammal communities is made by representatives of the Siberian fauna type, with the exception of the western part of the subzone, where European species predominate. [ABSTRACT FROM AUTHOR]

Ljungan virus (LV), which belongs to the Parechovirus genus in the Picornaviridae family, was first isolated from bank voles (Myodes glareolus) in Sweden in 1998 and proposed as a zoonotic agent. To improve knowledge of the host association and geographical distribution of LV, tissues from 1685 animals belonging to multiple rodent and insectivore species from 12 European countries were screened for LV-RNA using reverse transcriptase (RT)-PCR. In addition, we investigated how the prevalence of LV-RNA in bank voles is associated with various intrinsic and extrinsic factors. We show that LV is widespread geographically, having been detected in at least one host species in nine European countries. Twelve out of 21 species screened were LV-RNA PCR positive, including, for the first time, the red vole (Myodes rutilus) and the root or tundra vole (Alexandromys formerly Microtus oeconomus), as well as in insectivores, including the bicolored white-toothed shrew (Crocidura leucodon) and the Valais shrew (Sorex antinorii). Results indicated that bank voles are the main rodent host for this virus (overall RT-PCR prevalence: 15.2%). Linear modeling of intrinsic and extrinsic factors that could impact LV prevalence showed a concave-down relationship between body mass and LV occurrence, so that subadults had the highest LV positivity, but LV in older animals was less prevalent. Also, LV prevalence was higher in autumn and lower in spring, and the amount of precipitation recorded during the 6 months preceding the trapping date was negatively correlated with the presence of the virus. Phylogenetic analysis on the 185 base pair species-specific sequence of the 5′ untranslated region identified high genetic diversity (46.5%) between 80 haplotypes, although no geographical or host-specific patterns of diversity were detected. [ABSTRACT FROM AUTHOR]

Euchromatic segments of the X chromosomes of placental mammals are the most conservative elements of the karyotype, only rarely subjected to either inter- or intrachromosomal rearrangements. Here, using microdissection-derived set of region-specific probes of Terricola savii we detailed the evolutionary rearrangements found in X chromosomes in 20 vole species (Arvicolinae, Rodentia). We show that the evolution of X chromosomes in this taxon was accompanied by multiple para- and pericentric inversions and centromere shifts. The contribution of intrachromosomal rearrangements to the karyotype evolution of Arvicolinae species was approximately equivalent in both the separate autosomal conserved segments and the X chromosomes. Intrachromosmal rearrangements and structural reorganization of the X chromosomes was likely accompanied by an accumulation, distribution, and evolution of repeated sequences. [ABSTRACT FROM AUTHOR]

Ecological monitoring of small mammal occurrence on Ushant Island (Brittany, France) revealed the presence of the bank vole (Myodes glareolus) in September 2017. This was the first report of the bank vole on the island. Evaluation of previous small mammal monitoring and analysis of several batches of barn owl pellets allowed us to conclude that the arrival on the island is recent, sometime between 1995 and 2017. Further study is necessary to determine whether the current population, still incompletely distributed into suitable habitats of the island, will be self-sustaining on a long-term basis. [ABSTRACT FROM AUTHOR]

Human-wildlife conflicts often centre on economic loss caused by wildlife. Yet despite being a major issue for land-managers, estimating total prey losses to predation can be difficult. Estimating impacts of protected wildlife on economically important prey can also help management decisions to be evidence-led. The recovery in population and range of common buzzards Buteo buteo in Britain has brought them into conflict with some gamebird interests. However, the magnitude of any impact is poorly understood. We used bioenergetics models that combine measures of buzzard abundance from field surveys with diets assessed by using cameras at nests, prey remains and pellet analysis, to estimate their impact on red grouse Lagopus lagopus scotica on a large (115 km2) moor managed for red grouse shooting in Scotland. Whilst grouse consumption by individual buzzards was lower than previous estimates for other raptor species present on our study site, total consumption could be greater given an estimated 55–73 buzzards were present on the study site year-round. Averaging across diet assessment methods, consumption models estimated that during each of three breeding seasons (April-July 2011–2013), the buzzards foraging on our study site consumed 73–141 adult grouse and 77–185 chicks (depending on year). This represented 5–11% of adult grouse present in April (22–67% of estimated adult mortality) and 2–5% of chicks that hatched (3–9% of estimated chick mortality). During two non-breeding seasons (August-March), consumption models using pellet analysis estimated that buzzards ate a total of 242–400 grouse, equivalent to 7–11% of those present at the start of August and 14–33% of estimated grouse mortality during the non-breeding season. Buzzard consumption of grouse has the potential to lead to non-trivial economic loss to grouse managers, but only if buzzards predated the grouse they ate, and if grouse mortality is additive to other causes. [ABSTRACT FROM AUTHOR]

In the present study, on the basis of cytogenetic and molecular genetic (mtDNA control region) analysis, genetic variability of the Muya valley vole, Alexandromys mujanensis, an endemic of Buryatia and the northwest of Zabaykalsky krai, was assessed. Three isolated valley vole populations from the Muisko-Kuandinskaya and Barguzinskaya depressions, as well as the Baunt Lake valley, were examined. Polymorphism in the number of autosomal arms (NFa = 46–49) with a stable number of chromosomes (2n = 38), determined by morphological variability of four pairs of autosomes (MMUJ2, MMUJ7, MMUJ8, and MMUJ14), rather than two, as previously thought, was revealed. To date, for the Muya valley vole, ten karyotype variants have been identified. It seems likely that chromosomal rearrangements (pericentric inversions, as well as two variants of fusion of acrocentric chromosome pairs, i.e., centromeric-centromeric and centromeric-telomeric), which led to variability in autosome morphology in the populations of the Muya valley vole, are not harmful. Analysis of the mtDNA control region revealed high haplotype and nucleotide diversity for the species as a whole, while in the valley vole samples from the Dzherginsky Nature Reserve (Barguzinskaya Depression) and the Baunt lake valley, nucleotide diversity was reduced compared to the sample from the Muisko-Kuandinskaya Depression. Despite the fact that each of the studied populations has a unique composition of chromosomal rearrangements and mtDNA haplotypes, higher similarity between the populations of the Muisko-Kuandinskaya Depression and the populations of the Baunt lake valley can still be suggested. [ABSTRACT FROM AUTHOR]

The evidence that diel patterns of physiology and behaviour in mammals are governed by circadian ‘clocks’ is based almost entirely on studies of nocturnal rodents. The emergent circadian paradigm, however, neglects the roles of energy metabolism and alimentary function (feeding and digestion) as determinants of activity pattern. The temporal control of activity varies widely across taxa, and ungulates, microtine rodents, and insectivores provide examples in which circadian timekeeping is vestigial. The nocturnal rodent/human paradigm of circadian organisation is unhelpful when considering the broader manifestation of activity patterns in mammals. [ABSTRACT FROM AUTHOR]

The American mink Neovison vison has been introduced to Italy for fur farms in the 1950s. Since the 1970s, free-ranging individuals are present in north-eastern Italy, where an expanding population still occurs. In our work, we aimed at assessing the seasonal diet of invasive American mink introduced to north-eastern Italy. Thus, a total of 195 mink scats (N = 73, June 2007; N = 57, September 2007; N = 65, February 2008) were collected. Scats were washed and food remains isolated and classified through comparison with reference collections and atlases. Absolute and relative frequencies, as well as the estimated volume of each prey category were computed. The endemic Italian water vole Arvicola italicus represented the staple of the diet of the American mink in June (relative frequency: 20.4%, total volume in diet: 38.1%) and September (relative frequency: 22.7%, total volume in diet: 52.0%). Other small mammals, amphibians (Rana spp. and Pelophylax spp.) and the invasive red swamp crayfish Procambarus clarkii were mostly consumed in cold months, when water voles are not available. Differently from other study areas, wading birds and fish were rarely consumed, possibly because of their low local availability, if compared with small mammals. No law currently protects the endemic water vole, which may be furtherly threatened by the potential range expansion of invasive minks. Therefore, eradication of this alien carnivore should be recommended before local population decline of water vole become irreversible, and before minks reach populations of native riverine mustelids, i.e. the western polecat and the Eurasian otter. [ABSTRACT FROM AUTHOR]

Two releases from steam assisted gravity drainage (SAGD) wellheads occurred 3 yr apart. To track recovery of the affected areas, red‐backed voles were studied 1 and 4 yr later, using population estimates, hepatic detoxification effort, body condition, and tissue metal levels as bioindicators of site recovery. From years 1 to 4, higher ethoxyresorufin‐O‐deethylase induction was no longer evident, capture rate was lower, and body lead residues were no longer (inversely) correlated with body condition. Environ Toxicol Chem 2019;38:1542–1548. © 2019 SETAC [ABSTRACT FROM AUTHOR]

Pacific martens (Martes caurina) are often associated with mature forests with complex structure for denning, resting, and efficient hunting. Nonetheless, a small isolated population of the Humboldt subspecies of Pacific martens (Martes caurina humboldtensis) occupies a narrow strip of young, coastal forest (< 70 years old) but not inland mature forest in the central Oregon Coast Range. We examined factors contributing to this unexpected distribution of martens by 1) analyzing marten diets using DNA metabarcoding to assess 90 scats, 2) using camera traps to assess differences in the relative abundances of prey, competitors, and predators across a coastal to inland gradient of vegetation types, and 3) quantifying differences in extent of fruit-producing shrubs and vegetation structure within vegetation types. Diets of martens were diverse (12, 10, and 3 species of birds, mammals, and amphibians respectively), and most fall and winter scats contained fruit. Voles, mice, and varied thrushes (Ixoreus naevius) were dominant prey items. Voles, mice, and most birds, but not varied thrushes, were more commonly observed in the coastal shrub-dominated forest than in inland forest. The coastal shrub-dominated forest had the highest diversity of vertebrates and potential prey overall. Bobcats (Lynx rufus), a key potential predator, were more commonly detected in inland forest. Of potential competitors, western spotted skunks (Spilogale gracilis) were more commonly detected in inland forest, with gray foxes (Urocyon cinereoargenteus) and raccoons (Procyon lotor) detected almost exclusively in coastal forests. Vegetation in coastal forests appears to provide, at least seasonally, more prey and fruit, and more overhead shrub cover compared with inland forest. Remaining plausible hypotheses for the restricted distribution of marten to coastal forests include increased prey, fruit, and overhead cover, and reduced predation risk from bobcats. [ABSTRACT FROM AUTHOR]

Experiments were performed to estimate the effect of removal trapping with Gero trap lines on resident population density and dispersal rate of Clethrionomys voles and Sorex shrews. Parameters of animal density and dispersal were calculated based on the results of live-trap censuses taken before and immediately after the removal trapping. Resident population density in the latter case was accounted for not only by animals that escaped removal but also by those that moved in from surrounding areas during the next few days. Local reduction of animal numbers resulted in increased dispersal. Parameters of dispersal obtained by the method of long-term removal may be overestimated. [ABSTRACT FROM AUTHOR]

The control of mammalian pests relies heavily on the use of pesticides that are often avoided and are not species-specific. These problems are particularly acute for pesticides used to control rats (Rattus spp.). The efficacy and targeting of control could be improved by attracting animals to control measures using species-specific cues. One cue that has the potential to attract rats is the 50 kHz calls they emit in positive social situations. Here we test the potential of these rat calls as a species-specific attractant by examining the response of laboratory rats (Rattus norvegicus; n = 48) and non-target bank voles (Myodes glareolus; n = 16) to 50 kHz calls from either sex in a compartmentalised laboratory arena. Sounds of rat movement and white noise acted as control treatments, with each sound tested against a silent control in the opposite side of the arena. When sound cues were played above an empty bait box, rats were attracted to spend time close to 50 kHz rat calls, climbing on top of boxes, regardless of the sex of subject or caller. When either 50 kHz rat calls or rat movement sounds were played inside an empty bait box, rats of both sexes spent 3–4 fold more time inside boxes and visited more frequently. Rats were not attracted by intermittent white noise. Bank voles were neither attracted to, nor avoided, 50 kHz rat calls played inside empty bait boxes. Our findings show that 50 kHz rat calls are an effective attractant for rats of both sexes under laboratory conditions, while not attracting non-target bank voles. These calls are strong candidates for providing a species-specific lure that may be attractive even in the absence of food bait, but further trials will be needed to assess their efficacy under field conditions. [ABSTRACT FROM AUTHOR]

The protein-only hypothesis predicts that infectious mammalian prions are composed solely of PrPSc, a misfolded conformer of the normal prion protein, PrPC. However, protein-only PrPSc preparations lack significant levels of prion infectivity, leading to the alternative hypothesis that cofactor molecules are required to form infectious prions. Here, we show that prions with parental strain properties and full specific infectivity can be restored from protein-only PrPSc in vitro. The restoration reaction is rapid, potent, and requires bank vole PrPC substrate, post-translational modifications, and cofactor molecules. To our knowledge, this represents the first report in which the essential properties of an infectious mammalian prion have been restored from pure PrP without adaptation. These findings provide evidence for a unified hypothesis of prion infectivity in which the global structure of protein-only PrPSc accurately stores latent infectious and strain information, but cofactor molecules control a reversible switch that unmasks biological infectivity. [ABSTRACT FROM AUTHOR]

Improving detection probabilities for rare species is critical when assessing presence or habitat associations. Our goal was to create a new small mammal trapping protocol that improved detection of rare species, such as the olive-backed pocket mouse (Perognathus fasciatus). We used three trap and bait types and trapped an area 4.4 times larger than the standard grid. We also assessed the effect of captures of non-target species on detection probability of pocket mice. Regardless of species, trap success was higher for Havaharts. We found that bait and trap type selection varied significantly by species, with pocket mice showing strongest selection for Havahart traps baited with bird seed. Increasing grid size, while maintaining a similar trapping effort, resulted in higher detection probability, although our analyses showed that effective grids can be about three-quarters of the size we use to achieve similar results. We were also able to demonstrate that by deploying a combination of different traps and baits it is possible to overcome the potential effect of non-target species (e.g., deer mice, Peromyscus maniculatus) on the detection probability of pocket mice. Our results show that simple changes to standard small-mammal trapping methods can dramatically increase the detectability of rare and elusive small mammals. Increasing detection probability of rare components of a community can improve the results and understanding of future studies. [ABSTRACT FROM AUTHOR]

The diversity of viruses probably exceeds biodiversity of eukaryotes, but little is known about the origin and emergence of novel virus species. Experimentation and disease outbreak investigations have allowed the characterization of rapid molecular virus adaptation. However, the processes leading to the establishment of functionally distinct virus taxa in nature remain obscure. Here, we demonstrate that incipient speciation in a natural host species has generated distinct ecological niches leading to adaptive isolation in an RNA virus. We found a very strong association between the distributions of two major phylogenetic clades in Tula orthohantavirus (TULV) and the rodent host lineages in a natural hybrid zone of the European common vole (Microtus arvalis). The spatial transition between the virus clades in replicated geographic clines is at least eight times narrower than between the hybridizing host lineages. This suggests a strong barrier for effective virus transmission despite frequent dispersal and gene flow among local host populations, and translates to a complete turnover of the adaptive background of TULV within a few hundred meters in the open, unobstructed landscape. Genetic differences between TULV clades are homogenously distributed in the genomes and mostly synonymous (93.1%), except for a cluster of nonsynonymous changes in the 5′ region of the viral envelope glycoprotein gene, potentially involved in host-driven isolation. Evolutionary relationships between TULV clades indicate an emergence of these viruses through rapid differential adaptation to the previously diverged host lineages that resulted in levels of ecological isolation exceeding the progress of speciation in their vertebrate hosts. [ABSTRACT FROM AUTHOR]

Abstract: Our hypothesis that exoanthropic forest rodent species (e.g., bank voles) avoid the urinary odor of the synanthropic house mice was tested in field experiments in August 2016. One count of the small mammals was carried out in each of two 4-ha fields by the capture-mark-recapture technique over 12 days. Two hundred live traps (100 points, 2 traps per point) were exposed and controlled twice a day (early in the morning and in the evening) in each count. One trap in each pair served as the reference, while the second was the experimental one with 20 μL of the urine of synanthropic house mice applied to a foam rubber surface every day. Generally, bank voles chose the odorless trap more often (60.8% vs. 39.2%, χ2 = 3.7, p = 0.054). Adult individuals had a nonsignificant tendency to avoid the odor-emitting traps. Immature (subadult and juvenile) bank voles reliably avoided the odor-emitting traps (a 2 : 1 ratio, χ2 = 5.74, p = 0.017). A general linear model showed the influence of the age of voles on the choice of the odorless traps. The potential repellent role of sulfur-containing compounds in mouse urine is discussed. [ABSTRACT FROM AUTHOR]

Abstract: 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. [ABSTRACT FROM AUTHOR]

The El Mirón Cave site in Spain has one of the most complete archaeological and palaeontological records of the Late Pleistocene in the Iberian Peninsula, encompassing most of the last c. 50,000 years. Among other studies, the fossiliferous record has allowed the development of various interpretations of faunal and climatic changes during this period of time in the northern Atlantic region of the Iberian Peninsula. The addition of more radiocarbon dates from El Mirón Cave make it possible to revise some of the interpretations of the micromammal sequence carried out earlier for this major site. The record of small mammals is one of the most used tools to study the climate of the past, and among them the several Arvicolinae species are of great importance for the study of Quaternary climatic variations, due to their adaptations to a great diversity of habitats. New methodologies such as ancient DNA and geometric morphometric analyses now permit us to conduct a review of the Arvicolinae species previously described at this site and better to differentiate between species with similar morphologies, like Microtus arvalis and M. agrestis. We also identified the presence of a species not recorded before in El Mirón, Terricola pyrenaicus. With the study of the Arvicolinae species associations, we reaffirm the climate variations originally described in this deposit, indicating in detail how the successive changes in temperature and environment took place throughout the course of the late Last Glacial and early Postglacial periods (Marine Isotope Stages 3–1). • Review of the Arvicolinae association in the El Mirón Cave. • Using geometric morphometry to differentiate morphologically similar species. • Using ancient DNA analysis to identify a new specie in this site. • Climatic variations during the Late Pleistocene in the northern Iberian Peninsula. [ABSTRACT FROM AUTHOR]

Wild rodents are important hosts for tick larvae but co-infestations with other mites and insects are largely neglected. Small rodents were trapped at four study sites in Berlin, Germany, to quantify their ectoparasite diversity. Host-specific, spatial and temporal occurrence of ectoparasites was determined to assess their influence on direct and indirect zoonotic risk due to mice and voles in an urban agglomeration. Rodent-associated arthropods were diverse, including 63 species observed on six host species with an overall prevalence of 99%. The tick Ixodes ricinus was the most prevalent species, found on 56% of the rodents. The trapping location clearly affected the presence of different rodent species and, therefore, the occurrence of particular host-specific parasites. In Berlin, fewer temporary and periodic parasite species as well as non-parasitic species (fleas, chiggers and nidicolous Gamasina) were detected than reported from rural areas. In addition, abundance of parasites with low host-specificity (ticks, fleas and chiggers) apparently decreased with increasing landscape fragmentation associated with a gradient of urbanisation. In contrast, stationary ectoparasites, closely adapted to the rodent host, such as the fur mites Myobiidae and Listrophoridae, were most abundant at the two urban sites. A direct zoonotic risk of infection for people may only be posed by Nosopsyllus fasciatus fleas, which were prevalent even in the city centre. More importantly, peridomestic rodents clearly supported the life cycle of ticks in the city as hosts for their subadult stages. In addition to trapping location, season, host species, body condition and host sex, infestation with fleas, gamasid Laelapidae mites and prostigmatic Myobiidae mites were associated with significantly altered abundance of I. ricinus larvae on mice and voles. Whether this is caused by predation, grooming behaviour or interaction with the host immune system is unclear. The present study constitutes a basis to identify interactions and vector function of rodent-associated arthropods and their potential impact on zoonotic diseases. [ABSTRACT FROM AUTHOR]

Spatial capture-recapture modelling (SCR) is a powerful analytical tool to estimate density and derive information on space use and behaviour of elusive animals. Yet, SCR has been seldom applied to the study of ecologically keystone small mammals. Here we highlight its potential and requirements with a case study on common voles (Microtus arvalis). First, we address mortality associated with live-trapping, which can be high in small mammals, and must be kept minimal. We designed and tested a nest box coupled with a classic Sherman trap and show that it allows a 5-fold reduction of mortality in traps. Second, we address the need to adjust the trapping grid to the individual home range to maximize spatial recaptures. In May-June 2016, we captured and tagged with transponders 227 voles in a 1.2-ha area during two monthly sessions. Using a Bayesian SCR with a multinomial approach, we estimated: (1) the baseline detection rate and investigated variation according to sex, time or behaviour (aversion/attraction after a previous capture); (2) the parameter sigma that describes how detection probability declines as a function of the distance to an individual´s activity centre, and investigated variation according to sex; and (3) density and population sex-ratio. We show that reducing the maximum distance between traps from 12 to 9.6m doubled spatial recaptures and improved model predictions. Baseline detection rate increased over time (after overcoming a likely aversion to entering new odourless traps) and was greater for females than males in June. The sigma parameter of males was twice that of females, indicating larger home ranges. Density estimates were of 142.92±38.50 and 168.25±15.79 voles/ha in May and June, respectively, with 2–3 times more females than males. We highlight the potential and broad applicability that SCR offers and provide specific recommendations for using it to study small mammals like voles. [ABSTRACT FROM AUTHOR]

The alternative prey hypothesis predicts that the interaction between generalist predators and their main prey is a major driver of population dynamics of alternative prey species. In Fennoscandia, changes in climate and human land use are assumed to alter the dynamics of cyclic small rodents (main prey) and lead to increased densities and range expansion of an important generalist predator, the red fox Vulpes vulpes. In order to better understand the role of these potential changes in community structure on an alternative prey species, willow ptarmigan Lagopus lagopus, we analyzed nine years of population census data from SE Norway to investigate how community interactions affected their population dynamics. The ptarmigan populations showed no declining trend during the study period, and annual variations corresponded with marked periodic small rodent peaks and declines. Population growth and breeding success were highly correlated, and both demographic variables were influenced by an interaction between red fox and small rodents. Red foxes affected ptarmigan negatively only when small rodent abundance was low, which is in accordance with the alternative prey hypothesis. Our results confirm the important role of red fox predation in ptarmigan dynamics, and indicate that if small rodent cycles are disrupted, this may lead to decline in ptarmigan and other alternative prey species due to elevated predation pressure. [ABSTRACT FROM AUTHOR]

We examined the fecal microbiota of female prairie voles. This species is socially and, likely, sexually monogamous, and thus serves as a valuable model in which to examine the interaction between the microbiota-gut-brain axis and social behavior. At present, little is known about the gastrointestinal microbiota of prairie voles; therefore, we performed a first characterization of the fecal microbiota using 16S rRNA gene amplicon sequencing. Semiconductor sequencing technology on an Ion Torrent PGM platform was used to assess the composition of fecal microbiotas from twelve female prairie voles. Following quality filtering, 1,017,756 sequencing reads were classified from phylum to genus level. At the phylum level, Firmicutes, Bacteroidetes, and Saccharibacteria were the predominant taxa, while the Bacteriodales, Erysipelotrichaceae, Ruminococcaceae, and Lachnospiraceae contributed the most dominant microbial groups and genera. Microbial community membership was most similar between vole sibling pairs, but consideration of taxon abundances weakened these associations. The interdependence of host factors such as genetics and behavior with the gastrointestinal microbiota is likely to be particularly pronounced in prairie voles. Our pilot characterization of the prairie vole intestinal microbiota revealed a microbial community composition remarkably consistent with the monogastric alimentary system of these rodents and their diet rich in complex plant carbohydrates. The highly social nature of these animals poses specific challenges to microbiome analyses that nonetheless are valuable for advancing research on the microbiota-gut-brain-behavior axis. Our study provides an important basis for future microbiome research in this emerging model organism for studying social behavior. [ABSTRACT FROM AUTHOR]

Very solid evidence suggests that the core of full length PrPSc is a 4-rung β-solenoid, and that individual PrPSc subunits stack to form amyloid fibers. We recently used limited proteolysis to map the β-strands and connecting loops that make up the PrPSc solenoid. Using high resolution SDS-PAGE followed by epitope analysis, and mass spectrometry, we identified positions ~116/118, 133–134, 141, 152–153, 162, 169 and 179 (murine numbering) as Proteinase K (PK) cleavage sites in PrPSc. Such sites likely define loops and/or borders of β-strands, helping us to predict the threading of the β-solenoid. We have now extended this approach to recombinant PrPSc (recPrPSc). The term recPrPSc refers to bona fide recombinant prions prepared by PMCA, exhibiting infectivity with attack rates of ~100%. Limited proteolysis of mouse and bank vole recPrPSc species yielded N-terminally truncated PK-resistant fragments similar to those seen in brain-derived PrPSc, albeit with varying relative yields. Along with these fragments, doubly N- and C-terminally truncated fragments, in particular ~89/97-152, were detected in some recPrPSc preparations; similar fragments are characteristic of atypical strains of brain-derived PrPSc. Our results suggest a shared architecture of recPrPSc and brain PrPSc prions. The observed differences, in particular the distinct yields of specific PK-resistant fragments, are likely due to differences in threading which result in the specific biochemical characteristics of recPrPSc. Furthermore, recombinant PrPSc offers exciting opportunities for structural studies unachievable with brain-derived PrPSc. [ABSTRACT FROM AUTHOR]

The article discusses the tularemia epidemiology in Europe. It states that tularemia is both terrestrial and distinct aquatic life cycle. It mentions that the fluctuations in abundance of wild herbivorous mammals such as hares and voles plays important role in tularemia epidemiology in European countries including Sweden, Finland, and Czech Republic.

Inbred mouse strains, living in simple laboratory environments far removed from nature, have been shown to vary consistently in their immune response. However, wildlife populations are typically outbreeding and face a multiplicity of challenges, parasitological and otherwise. In this study we seek evidence of consistent difference in immunological profile amongst individuals in the wild. We apply a novel method in this context, using longitudinal (repeated capture) data from natural populations of field voles, Microtus agrestis, on a range of life history and infection metrics, and on gene expression levels. We focus on three immune genes, IFN-γ, Gata3, and IL-10, representing respectively the Th1, Th2 and regulatory elements of the immune response. Our results show that there was clear evidence of consistent differences between individuals in their typical level of expression of at least one immune gene, and at most all three immune genes, after other measured sources of variation had been taken into account. Furthermore, individuals that responded to changing circumstances by increasing expression levels of Gata3 had a correlated increase in expression levels of IFN-γ. Our work stresses the importance of acknowledging immunological variation amongst individuals in studies of parasitological and infectious disease risk in wildlife populations. [ABSTRACT FROM AUTHOR]

We combined new sequence data for more than 300 muroid rodent species with our previously published sequences for up to five nuclear and one mitochondrial genes to generate the most widely and densely sampled hypothesis of evolutionary relationships across Muroidea. An exhaustive screening procedure for publically available sequences was implemented to avoid the propagation of taxonomic errors that are common to supermatrix studies. The combined data set of carefully screened sequences derived from all available sequences on GenBank with our new data resulted in a robust maximum likelihood phylogeny for 900 of the approximately 1,620 muroids. Several regions that were equivocally resolved in previous studies are now more decisively resolved, and we estimated a chronogram using 28 fossil calibrations for the most integrated age and topological estimates to date. The results were used to update muroid classification and highlight questions needing additional data. We also compared the results of multigene supermatrix studies like this one with the principal published supertrees and concluded that the latter are unreliable for any comparative study in muroids. In addition, we explored diversification patterns as an explanation for why muroid rodents represent one of the most species-rich groups of mammals by detecting evidence for increasing net diversification rates through time across the muroid tree. We suggest the observation of increasing rates may be due to a combination of parallel increases in rate across clades and high average extinction rates. Five increased diversification-rate-shifts were inferred, suggesting that multiple, but perhaps not independent, events have led to the remarkable species diversity in the superfamily. Our results provide a phylogenetic framework for comparative studies that is not highly dependent upon the signal from any one gene. [ABSTRACT FROM AUTHOR]

Bigger is apparently frequently fitter, and body size is typically heritable, so why don’t animals in wild populations evolve towards larger sizes? Different explanations have been proposed for this apparent “paradox of stasis.” A new study of snow voles in the Swiss Alps finds higher survival in animals with larger body mass and heritability of body mass, but, surprisingly, a genetic decline in body mass is also indicated. The authors suggest a novel explanation for this observation: the appearance of positive phenotypic selection is driven by a confounding variable of the age at which a juvenile is measured, whereas the evolutionarily relevant selection actually acts negatively on mass via its association with development time. Thus, genes for larger mass are not actually “fitter” because they are associated with longer development times, and juvenile snow voles with longer development times run the risk of not completing development before the first winter snow. However, the genetic decline in body size is not apparent at the phenotypic level, presumably because of countervailing trends in environmental effects on the phenotype. [ABSTRACT FROM AUTHOR]

Prions are amyloid-forming proteins that cause transmissible spongiform encephalopathies through a process involving conversion from the normal cellular prion protein to the pathogenic misfolded conformation (PrPSc). This conversion has been used for in vitro assays including serial protein misfolding amplification and real-time quaking induced conversion (RT-QuIC). RT-QuIC can be used for the detection of prions in a variety of biological tissues from humans and animals. Extensive work has been done to demonstrate that RT-QuIC is a rapid, specific, and highly sensitive prion detection assay. RT-QuIC uses recombinant prion protein to detect minute amounts of PrPSc. RT-QuIC has been successfully used to detect PrPSc from different prion diseases with a variety of substrates including hamster, human, sheep, bank vole, bovine and chimeric forms of prion protein. However, recombinant bovine prion protein has not been used to detect transmissible mink encephalopathy (TME) or to differentiate types of bovine spongiform encephalopathy (BSE) in samples from cattle. We evaluated whether PrPSc from TME and BSE infected cattle can be detected with RT-QuIC using recombinant bovine prion proteins, and optimized the reaction conditions to specifically detect cattle TME and to discriminate between classical and atypical BSE by conversion efficiency. We also found that substrate composed of the disease associated E211K mutant protein can be effective for the detection of TME in cattle and that wild type prion protein appears to be a practical substrate to discriminate between the different types of BSEs. [ABSTRACT FROM AUTHOR]

Prions are unique infectious agents, consisting solely of abnormally-folded prion protein (PrPSc). However, they possess virus-like features, including strain diversity, the ability to adapt to new hosts and to be altered evolutionarily. Because prions lack genetic material (DNA and RNA), these biological phenomena have been attributed to the structural properties of PrPSc. Therefore, many structural models of the structure of PrPSc have been proposed based on the limited structural information available, regardless of the incompatibility with high-resolution structural analysis. Recently hypothesized models consist solely of β-sheets and intervening loops/kinks; i.e. parallel in-register β-sheet and β-solenoid models. Owing to the relative simplicity of these structural models of PrPSc, we hypothesized that numerical conversion of the primary structures with a relevant algorithm would enable quantitative comparison between PrPs of distinct primary structures. We therefore used the theoretical values of β-sheet (Pβ) and random-coil (Pc) propensity calculated by secondary structure prediction with a neural network, to analyze interspecies transmission of prions. By reviewing experiments in the literature, we ascertained the biological relevance of Pβ and Pc and found that these classical parameters surprisingly carry substantial information of amyloid structures. We also demonstrated how these parameters could aid in interpreting and explaining phenomena in interspecies transmissions. Our approach can lead to the development of a versatile tool for investigating not only prions but also other amyloids. [ABSTRACT FROM AUTHOR]