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1.
Emerg Infect Dis ; 27(4): 1193-1195, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33754987

RESUMO

After experimental inoculation, severe acute respiratory syndrome coronavirus 2 infection was confirmed in bank voles by seroconversion within 8 days and detection of viral RNA in nasal tissue for up to 21 days. However, transmission to contact animals was not detected. Thus, bank voles are unlikely to establish effective transmission cycles in nature.


Assuntos
Arvicolinae , Transmissão de Doença Infecciosa , Doenças dos Roedores , Soroconversão , Eliminação de Partículas Virais , Animais , Anticorpos Antivirais , /transmissão , Modelos Animais de Doenças , Suscetibilidade a Doenças , Mucosa Nasal/virologia , Doenças dos Roedores/imunologia , Doenças dos Roedores/transmissão , Doenças dos Roedores/virologia
2.
Zootaxa ; 4920(4): zootaxa.4920.4.1, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33756643

RESUMO

Neacomys Thomas, 1900 is an oryzomyine genus comprising at least 17 lineages distributed from easternmost Panama to northern Bolivia. As is the case for other groups of the subfamily Sigmodontinae, Neacomys have experienced a substantial increase in the rate of species descriptions in the last two decades, prompted by the progressive generation of morphological, molecular and karyological data. Nevertheless, most of the studies related to the genus have focused on the assessment of Cis-Andean populations, so that the Trans-Andean ones have been relegated to the background. In more than a century, only two species have been described from that region, one of them present in Colombia (N. tenuipes Thomas, 1900). Here, a new species of Neacomys is named and described based on samples collected in montane ecosystems of the Serranía de los Yariguíes, an isolated massif in the Magdalena Valley (Trans-Andean Colombia). Its validity is supported by a unique combination of morphological and molecular characters: Neacomys sp. nov. can be distinguished from other congeners mainly by the presence of broad ochraceous-orange patches on the sides of the muzzle, a gray-based ochraceous buff ventral fur, a thick hamular process of the squamosal, an opened ectotympanic ring, and a narrow anterocone of M1. The species is recovered as a clearly divergent and well-supported monophyletic group in the phylogenies, which implies it is not closely related to any other species in the genus and probably represents an early radiation within it. The new species of Neacomys constitutes the only rodent described from Colombia in more than 50 years and brings the list of mammals of the country to 529 species. Its discovery evidences that Trans-Andean region could be an important source of hidden diversity for the genus, and in Colombia, for rodents in general. Thus, further inventories, especially into remote areas, are needed to unveil this diversity. The fact that the new species seems to be endemic to an isolated mountain range implies it merits attention in terms of conservation.


Assuntos
Arvicolinae , Roedores , Animais , Colômbia , Ecossistema , Filogenia , Sigmodontinae
3.
Ecotoxicol Environ Saf ; 208: 111721, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396052

RESUMO

The City of Yellowknife is a known hotspot of arsenic contamination and there is a growing body of evidence suggesting that local wildlife in the vicinity of the abandoned Giant Mine site may be at risk of decreased bone mineralization and various bone disorders. The purpose of this study was to preliminarily measure bone mineral density (BMD) changes and investigate the incidence, pattern, and severity of bone lesions in wild muskrats and red squirrels breeding in three (3) catchment areas at different distances from the Giant Mine Site in Yellowknife, Northwest Territories (Canada): ~2 km (location 1), ~18 km (location 2), and ~40-100 km (location 3). Full femoral bones of 15 muskrats and 15 red squirrels were collected from the three sampling locations (5 from each location) and subjected to radiographic analysis and densitometric measurements. The patterns and severities of bone lesions, including changes in bone mineral density, were evaluated and compared between groups. As levels were significantly higher in the bones of muskrats caught from location 1 and 2, relative to location 3. Further, As and Cd levels were significantly higher in the bones of squirrels caught from locations 1 and 2 relative to squirrels caught from location 3. The preliminary results from bones revealed that radiographic abnormalities such as bone rarefaction, osteopenia, and thinning of the femoral shafts with significant ossific cystic lesions and bowing were the most common skeletal pathologies found in bones of red squirrels from the three locations. Radiographic appearances of massive sclerosis and dysplasia, including severe osteocondensation and osteopathia striata-like abnormalities, were found in the bones of muskrats from all the sampling locations. Densitometric evaluation showed no significant differences between the three locations in the bone parameters measured. However, there was a statistically significant correlation between As content in the bones of muskrats and percent fat content in the femur samples, which suggests that accumulation of As could have been a causal factor for a change in percent fat in femurs of muskrats.


Assuntos
Intoxicação por Arsênico/veterinária , Arsênico/efeitos adversos , Densidade Óssea/efeitos dos fármacos , Doenças Ósseas/veterinária , Poluentes Ambientais/envenenamento , Animais , Animais Selvagens , Arsênico/metabolismo , Intoxicação por Arsênico/diagnóstico por imagem , Intoxicação por Arsênico/patologia , Arvicolinae , Doenças Ósseas/induzido quimicamente , Doenças Ósseas/diagnóstico por imagem , Doenças Ósseas/patologia , Densitometria , Poluentes Ambientais/análise , Gorduras/metabolismo , Feminino , Fêmur/diagnóstico por imagem , Fêmur/efeitos dos fármacos , Fêmur/metabolismo , Fêmur/patologia , Territórios do Noroeste/epidemiologia , Sciuridae
4.
Oecologia ; 195(3): 601-622, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33369695

RESUMO

Most small rodent populations in the world have fascinating population dynamics. In the northern hemisphere, voles and lemmings tend to show population cycles with regular fluctuations in numbers. In the southern hemisphere, small rodents tend to have large amplitude outbreaks with less regular intervals. In the light of vast research and debate over almost a century, we here discuss the driving forces of these different rodent population dynamics. We highlight ten questions directly related to the various characteristics of relevant populations and ecosystems that still need to be answered. This overview is not intended as a complete list of questions but rather focuses on the most important issues that are essential for understanding the generality of small rodent population dynamics.


Assuntos
Ecossistema , Roedores , Animais , Arvicolinae , Surtos de Doenças , Dinâmica Populacional
5.
Zootaxa ; 4876(1): zootaxa.4876.1.1, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33311337

RESUMO

Oryzomyini represents the most diverse and speciose tribe of subfamily Sigmodontinae, with 29 genera and about 141 species. This great diversity of species is distributed from southeastern North to southern South America. Its systematics have passed through major changes in the last years due to the integration of molecular data with morphological characters in phylogenetic inferences. Unsurprisingly, cytogenetic studies on Oryzomyini reflect such diversity, with chromosome diploid number varying from 2n = 16 to 2n = 88. In addition, some species present autosomal and sex chromosome polymorphisms, besides the presence of B chromosomes. However, despite decades of cytogenetic studies, our knowledge about the karyotype variability in this group were still poorly known. Considering such deep and profound changes on the tribe, along with important new evidence that was continuously being produced associated to field work in several areas of Brazil and South America, we performed a cytogenetic review of the Oryzomyini group. We provide standardized descriptions summarizing all the knowledge associated to the known species of the tribe. We also describe seven new karyotypes for the tribe, Euryoryzomys sp., 2n = 58 and FN = 92; Neacomys sp. 1, 2n = 48 and FN = 54; Neacomys sp. 2, 2n = 54 and FN = 62; Oecomys sp. 1, 2n = 54 and FN = 84; Oecomys sp. 2, 2n = 64 and FN = 92; Oecomys sp. 3, 2n = 84 and FN = 110; and Scolomys sp., 2n = 62 and FN = 80.


Assuntos
Arvicolinae , Sigmodontinae , Animais , Coloração Cromossômica , Cariótipo , Filogenia , Roedores , Sigmodontinae/genética , Especificidade da Espécie
6.
Zootaxa ; 4861(3): zootaxa.4861.3.9, 2020 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-33311219

RESUMO

The region of Lagoa Santa, Minas Gerais, Brazil, is one of the most important karstic areas of the Brazilian Quaternary due to the faunistic diversity of living and extinct forms. Among them, some taxa remain poorly studied, as is the case of Calomys anoblepas Winge 1887. Despite the recent allocation of the taxon within Juliomys, its description and morphological analysis are condensed, based on comparative few specimens and on few informative characters. In this study, we investigate characters proposed to distinguish species of Juliomys, and reevaluate the taxonomic status of the fossil Juliomys anoblepas. We analyzed 80 cranio-dental morphological characters in 233 specimens represented by the four species currently recognized: J. pictipes (Osgood 1933), J. rimofrons Oliveira Bonvicino 2002, J. ossitenuis Costa, Pavan, Leite Fagundes 2007, and J. ximenezi Christoff, Vieira, Oliveira, Gonçalves, Valiati Tomasi 2016. We also performed principal component analysis on eight craniodental measurements available for the J. anoblepas hypodigm. The review of morphological systems and the evaluation of the characters used in the literature revealed that there are no diagnostic characters in the anterior portion of the skull and in the molar series of Juliomys, being difficult to differentiate the fossil from the other living species. Only six qualitative characters were variable and applicable to the hypodigm of J. anoblepas. Characters are polymorphic, invariable, or the fossil is not sufficiently complete to determinate its states. The taxon could not be morphometrically differentiated from J. pictipes and J. ossitenuis. Based on the results presented herein, we consider J. anoblepas as a nomen dubium and restrict its name to the taxon's hypodigm.


Assuntos
Arvicolinae , Sigmodontinae , Animais , Brasil , Fósseis , Filogenia , Roedores
7.
Proc Biol Sci ; 287(1941): 20202653, 2020 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-33352076

RESUMO

According to classic theory, species' population dynamics and distributions are less influenced by species interactions under harsh climatic conditions compared to under more benign climatic conditions. In alpine and boreal ecosystems in Fennoscandia, the cyclic dynamics of rodents strongly affect many other species, including ground-nesting birds such as ptarmigan. According to the 'alternative prey hypothesis' (APH), the densities of ground-nesting birds and rodents are positively associated due to predator-prey dynamics and prey-switching. However, it remains unclear how the strength of these predator-mediated interactions change along a climatic harshness gradient in comparison with the effects of climatic variation. We built a hierarchical Bayesian model to estimate the sensitivity of ptarmigan populations to interannual variation in climate and rodent occurrence across Norway during 2007-2017. Ptarmigan abundance was positively linked with rodent occurrence, consistent with the APH. Moreover, we found that the link between ptarmigan abundance and rodent dynamics was strongest in colder regions. Our study highlights how species interactions play an important role in population dynamics of species at high latitudes and suggests that they can become even more important in the most climatically harsh regions.


Assuntos
Aves , Clima , Roedores , Animais , Arvicolinae , Teorema de Bayes , Ecossistema , Cadeia Alimentar , Noruega , Dinâmica Populacional , Comportamento Predatório
8.
Elife ; 92020 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-33349334

RESUMO

The intricate lattice of Gn and Gc glycoprotein spike complexes on the hantavirus envelope facilitates host-cell entry and is the primary target of the neutralizing antibody-mediated immune response. Through study of a neutralizing monoclonal antibody termed mAb P-4G2, which neutralizes the zoonotic pathogen Puumala virus (PUUV), we provide a molecular-level basis for antibody-mediated targeting of the hantaviral glycoprotein lattice. Crystallographic analysis demonstrates that P-4G2 binds to a multi-domain site on PUUV Gc and may preclude fusogenic rearrangements of the glycoprotein that are required for host-cell entry. Furthermore, cryo-electron microscopy of PUUV-like particles in the presence of P-4G2 reveals a lattice-independent configuration of the Gc, demonstrating that P-4G2 perturbs the (Gn-Gc)4 lattice. This work provides a structure-based blueprint for rationalizing antibody-mediated targeting of hantaviruses.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Virus Puumala/imunologia , Proteínas Virais de Fusão/imunologia , Animais , Anticorpos Monoclonais/imunologia , Arvicolinae , Células HEK293 , Humanos
9.
PLoS One ; 15(12): e0244803, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33382847

RESUMO

Protozoan parasites of the genus Trypanosoma infect a broad diversity of vertebrates and several species cause significant illness in humans. However, understanding of the phylogenetic diversity, host associations, and infection dynamics of Trypanosoma species in naturally infected animals is incomplete. This study investigated the presence of Trypanosoma spp. in wild rodents and lagomorphs in northern New Mexico, United States, as well as phylogenetic relationships among these parasites. A total of 458 samples from 13 rodent and one lagomorph species collected between November 2002 and July 2004 were tested by nested PCR targeting the 18S ribosomal RNA gene (18S rRNA). Trypanosoma DNA was detected in 25.1% of all samples, with the highest rates of 50% in Sylvilagus audubonii, 33.1% in Neotoma micropus, and 32% in Peromyscus leucopus. Phylogenetic analysis of Trypanosoma sequences revealed five haplotypes within the subgenus Herpetosoma (T. lewisi clade). Focused analysis on the large number of samples from N. micropus showed that Trypanosoma infection varied by age class and that the same Trypanosoma haplotype could be detected in recaptured individuals over multiple months. This is the first report of Trypanosoma infections in Dipodomys ordii and Otospermophilus variegatus, and the first detection of a haplotype phylogenetically related to T. nabiasi in North America in S. audubonii. This study lends important new insight into the diversity of Trypanosoma species, their geographic ranges and host associations, and the dynamics of infection in natural populations.


Assuntos
Arvicolinae/parasitologia , Lagomorpha/parasitologia , Doenças dos Roedores/parasitologia , Trypanosoma/genética , Tripanossomíase/veterinária , Animais , New Mexico , Tripanossomíase/parasitologia
10.
Korean J Parasitol ; 58(5): 559-564, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33202508

RESUMO

A survey of rodents and chiggers associated with Orientia tsutsugamushi was conducted in a rural region of the Republic of Korea (Korea) between 2014 and 2018. Overall Apodemus agrarius 15.2% had the highest seropisitive for O. tsutsugamushi, followed by Myodes regulus 11.4%. Monthly risk factors using logistic regression analysis were not associated with O. tsutsugamushi infections in rodents. The overall prevalence rate of O. tsutsugamushi among chiggers was 0.3%. The chigger (Leptotrombidium scutellare) and monthly (October) risk factors were associated with O. tsutsugamushi human infections (P<0.05). Orientia tsutsugamushi infections are endemic in rodents in Korea and people, for example, soldiers who are active outdoors, must employ preventive measures, especially during October (P<0.05). When there are many reports of O. tsutsugamushi infections in Korea. The Boryong strain 85.7% (2/14) was the most common strain detected in chiggers, followed by the Shimokoshi 7.1% (1/14) and Karp 7.1% strains.


Assuntos
Arvicolinae/microbiologia , Arvicolinae/parasitologia , Doenças Endêmicas , Murinae/microbiologia , Murinae/parasitologia , Orientia tsutsugamushi/isolamento & purificação , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/microbiologia , Trombiculidae/microbiologia , Animais , Anticorpos Antibacterianos , Arvicolinae/imunologia , Humanos , Murinae/imunologia , Orientia tsutsugamushi/imunologia , Prevalência , República da Coreia/epidemiologia , População Rural , Tifo por Ácaros/prevenção & controle , Estações do Ano
11.
Oecologia ; 194(4): 621-634, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33141325

RESUMO

Foraging is risky and involves balancing the benefits of resource acquisition with costs of predation. Optimal foraging theory predicts where, when and how long to forage in a given spatiotemporal distribution of risks and resources. However, significant variation in foraging behaviour and resource exploitation remain unexplained. Using single foragers in artificial landscapes of perceived risks and resources with diminishing returns, we aimed to test whether foraging behaviour and resource exploitation are adjusted to risk level, vary with risk during different components of foraging, and (co)vary among individuals. We quantified foraging behaviour and resource exploitation for 21 common voles (Microtus arvalis). By manipulating ground cover, we created simple landscapes of two food patches varying in perceived risk during feeding in a patch and/or while travelling between patches. Foraging of individuals was variable and adjusted to risk level and type. High risk during feeding reduced feeding duration and food consumption more strongly than risk while travelling. Risk during travelling modified the risk effects of feeding for changes between patches and resulting evenness of resource exploitation. Across risk conditions individuals differed consistently in when and how long they exploited resources and exposed themselves to risk. These among-individual differences in foraging behaviour were associated with consistent patterns of resource exploitation. Thus, different strategies in foraging-under-risk ultimately lead to unequal payoffs and might affect lower trophic levels in food webs. Inter-individual differences in foraging behaviour, i.e. foraging personalities, are an integral part of foraging behaviour and need to be fully integrated into optimal foraging theory.


Assuntos
Comportamento Alimentar , Individualidade , Animais , Arvicolinae , Cadeia Alimentar , Humanos , Comportamento Predatório
12.
PLoS One ; 15(10): e0240136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33007017

RESUMO

The critically endangered Amargosa vole (Microtus californicus scirpensis) is found only in rare marsh habitat near Tecopa, California in a plant community dominated by three-square bulrush (Schoenoplectus americanus). Since the earliest research on the Amargosa vole, the existing paradigm has been that these voles are obligatorily dependent on bulrush as their only food source and for the three-dimensional canopy and litter structure it provides for predator avoidance. However, no prior research has confirmed the diet of the Amargosa vole. In this study we characterized the Amargosa vole' nutritional needs, analyzed the quality of bulrush by forage analysis, and performed microhistological and metabarcoding analyses of vole feces to determine what foods were consumed in the wild. All bulrush plant tissues analyzed were low in fat (from 0.9% of dry matter in roots to 3.6% in seeds), high in neutral detergent fiber (from 5.9% in rhizomes to 33.6% in seeds), and low in protein (7.3-8.4%). These findings support the conclusion that bulrush alone is unlikely to support vole survival and reproduction. Fecal microhistology and DNA metabarcoding revealed relatively diverse diets including plants in 14 families, with rushes (Juncaceae), bulrushes (Cyperaceae), and grasses (Poaceae) being the most common diet items. On microhistology, all analyzed samples contained bulrush, sedges (Carex sp.), rushes (Juncus sp.), and beaked spikerush (Eleocharis rostrellata) even from marshes where non-bulrush plants were uncommon. There was evidence of insects at <1% in two marshes but none in the remaining marshes. Metabarcoding detected ten genera of plants. When considering non-Schoenoplectus targets, for which metabarcoding had poor sensitivity, saltgrass (Distichlis spicata) was the most commonly detected species, with prominent contributions from seaside arrowgrass (Triglochin concinna) and yerba mansa (Anemopsis californica) as well. Diversity of vole diets generally increased with increasing site plant diversity, but differences were not statistically significant. Confirming details about dietary behaviors is critical for informing appropriate conservation planning including habitat management and reintroduction of voles into new sites.


Assuntos
Arvicolinae/fisiologia , Dieta , Espécies em Perigo de Extinção , Fenômenos Fisiológicos da Nutrição Animal , Animais , Arvicolinae/genética , Código de Barras de DNA Taxonômico , Fezes , Plantas , Áreas Alagadas
14.
Zootaxa ; 4834(3): zootaxa.4834.3.1, 2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-33056112

RESUMO

Chigger mites of northern Iran were studied on the basis of field collections from rodent hosts. Thirty-five species were recorded. Two new species, Cheladonta afshari Stekolnikov and Shamsi sp. nov., collected on Apodemus sp. in Guilan and Mazandaran Provinces, and Neotrombicula tehranensis Stekolnikov and Shamsi sp. nov., collected on Cricetulus migratorius and Chionomys sp. in Tehran Province, are described. One new synonym is established: Neotrombicula vernalis (Willmann, 1942) (= Neotrombicula kermani Kudryashova, 1977 syn. nov.). Seventeen species were recorded in Iran for the first time; thus, the number of known Iranian chiggers constitutes 104. The record of Neotrombicula autumnalis (Shaw, 1790) in Iran is important from the veterinarian and medical points of view, as this species attacks humans and domestic animals.


Assuntos
Trombiculidae , Animais , Animais Domésticos , Arvicolinae , Irã (Geográfico) , Murinae
15.
PLoS One ; 15(9): e0239029, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941509

RESUMO

In studies assessing tick abundance, the use of live traps to capture and euthanize rodent hosts is a commonly used method to determine their burden. However, captive animals can experience debilitating or fatal capture stress as a result prior to collection. An alternative method is the use of lethal traps, but this can potentially lead to tick drop-off between the time of capture and collection. In this study, in order to determine whether subjecting animals to capture stress is inevitable, we tested the difference in sheep tick (Ixodes ricinus) larval burdens between bank voles (Myodes glareolus) captured alive and euthanized, and lethally trapped bank voles. During 2017 and 2018, 1318 bank voles were captured using live (Ugglan Special no. 2) and lethal (Rapp2 Mousetrap) traps during two consecutive years over three seasons in two locations in Norway. Voles captured alive would remain captive until euthanized, while lethally trapped voles were killed instantly upon capture. Log-linear models, accounting for overdispersion, were used to determine whether trap type was influencing observed tick burden. Bank voles captured in lethal traps carried 5.7% more larvae compared to euthanized voles captured in live traps, but this difference was not significant (p = 0.420). Males were overall captured 2.7 times more frequently than females, and the sex ratio was equal in both trap types. This study shows that the use of lethal traps to determine tick burden of rodents is sufficiently reliable, without having to subject animals to potentially lethal stress, hereby reducing some ethical concerns of animal suffering and the results thereof, without compromising accuracy. Lethal trapping is also often more economical and practical, further favoring this collection method.


Assuntos
Arvicolinae/parasitologia , Monitoramento Epidemiológico/veterinária , Infestações por Carrapato/epidemiologia , Animais , Feminino , Ixodes/patogenicidade , Larva , Masculino , Noruega , Infestações por Carrapato/veterinária , Carrapatos/patogenicidade
16.
Parasitol Res ; 119(10): 3211-3220, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32888066

RESUMO

We investigated the effects of host sex and flea phenology (estimated as periods of high versus low abundance) on individual body size in four fleas of small mammals. Amalaraeus penicilliger and Ctenophthalmus uncinatus are ectoparasites of the bank vole Myodes glareolus, whereas Doratopsylla dasycnema and Palaeopsylla soricis are ectoparasites of the common shrew Sorex araneus. We found significant effects of host sex and phenology on the body size of all flea species, although there was no general trend in the directions of these effects. Larger A. penicilliger were found on female hosts, whereas larger P. soricis were found on male hosts. In the remaining species, larger fleas were collected from male hosts during periods of high abundance (male C. uncinatus and female D. dasycnema) and from female hosts during periods of low abundance (male C. uncinatus). Regarding phenology, larger fleas were recorded during periods of either high (A. penicilliger, C. uncinatus, D. dasycnema) or low (C. uncinatus, P. soricis) abundance, but this depended on flea and/or host sex. We conclude that the directions of the host sex and phenology effects varied between flea species. Furthermore, the direction of the host sex effect was mediated by the effect of phenology and vice versa.


Assuntos
Arvicolinae/parasitologia , Tamanho Corporal/fisiologia , Infestações por Pulgas , Sifonápteros/anatomia & histologia , Animais , Feminino , Masculino , Estações do Ano , Fatores Sexuais , Sifonápteros/fisiologia
17.
PLoS Pathog ; 16(9): e1008875, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32898162

RESUMO

Prions are unorthodox pathogens that cause fatal neurodegenerative diseases in humans and other mammals. Prion propagation occurs through the self-templating of the pathogenic conformer PrPSc, onto the cell-expressed conformer, PrPC. Here we study the conversion of PrPC to PrPSc using a recombinant mouse PrPSc conformer (mouse protein-only recPrPSc) as a unique tool that can convert bank vole but not mouse PrPC substrates in vitro. Thus, its templating ability is not dependent on sequence homology with the substrate. In the present study, we used chimeric bank vole/mouse PrPC substrates to systematically determine the domain that allows for conversion by Mo protein-only recPrPSc. Our results show that that either the presence of the bank vole amino acid residues E227 and S230 or the absence of the second N-linked glycan are sufficient to allow PrPC substrates to be converted by Mo protein-only recPrPSc and several native infectious prion strains. We propose that residues 227 and 230 and the second glycan are part of a C-terminal domain that acts as a linchpin for bank vole and mouse prion conversion.


Assuntos
Encéfalo/metabolismo , Proteínas PrPC/metabolismo , Proteínas PrPSc/metabolismo , Doenças Priônicas/metabolismo , Animais , Arvicolinae , Encéfalo/patologia , Cricetinae , Mesocricetus , Camundongos , Camundongos Transgênicos , Proteínas PrPC/genética , Proteínas PrPSc/genética , Doenças Priônicas/genética , Doenças Priônicas/patologia , Domínios Proteicos
18.
PLoS One ; 15(9): e0236155, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915780

RESUMO

Large brains in prey may select for adoption of anti-predator behavior that facilitates escape. Prey species with relatively large brains have been shown to be less likely to fall prey to predators. This results in the prediction that individuals that have been captured by predators on average should have smaller brains than sympatric conspecifics. We exploited the fact that Eurasian pygmy owls Glaucidium passerinum hoard small mammals and birds in cavities and nest-boxes for over-winter survival, allowing for comparison of the phenotype of prey with that of live conspecifics. In Northern Europe, main prey of pygmy owls are voles of the genera Myodes and Microtus, while forest birds and shrews are the most important alternative prey. Large fluctuations (amplitude 100-200-fold) in vole populations induce rapid numerical responses of pygmy owls to main prey populations, which in turn results in varying predation pressure on small birds. We found, weighed and measured 153 birds in food-stores of pygmy owls and mist-netted, weighed and measured 333 live birds of 12 species in central-western Finland during two autumns with low (2017) and high (2018) pygmy owl predation risk. In two autumns, individuals with large brains were captured later compared to individuals with small brains, consistent with the hypothesis that such individuals survived for longer. Avian prey of pygmy owls had smaller heads than live birds in autumn 2018 when predation risk by pygmy owls was high. This difference in head size was not significant in 2017 when predation risk by pygmy owls was reduced. Finally, avian survivors were in better body condition than avian prey individuals. These findings are consistent with the hypothesis that pygmy owls differentially prey on birds in poor condition with small brains. These findings are consistent with the hypothesis that predation risk imposed by pygmy owls on small birds in boreal forests varies depending on the abundance of the main prey (voles).


Assuntos
Comportamento Predatório , Estrigiformes , Animais , Arvicolinae/fisiologia , Encéfalo/fisiologia , Feminino , Masculino , Tamanho do Órgão , Estações do Ano , Musaranhos/fisiologia , Estrigiformes/fisiologia , Taiga
19.
Oecologia ; 193(3): 547-556, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32638120

RESUMO

The pace-of-life syndrome describes covariation between life-history, behavioral and physiological traits; while, the emerging behavioral-bioenergetics theory proposes mechanistic links between those traits in a spatial-ecological context. However, little is known about the association between the limits to metabolic rate and spatial performance (i.e., mobility, home range size) in free-living individuals. Here we show, for the first time at the intra-specific level, that mobility traits increased with the aerobic exercise capacity ([Formula: see text]O2max) in a wild rodent, the bank vole (Myodes glareolus): [Formula: see text]O2max affected directly the movement intensity, which in turn affected home ranges. The results show that evolution of high [Formula: see text]O2max could be driven by selection for spatial performance traits, and corroborate one of the key assumptions of the behavioral-bioenergetics theory. However, the minimum maintenance metabolism, measured as the basal metabolic rate (BMR), was not correlated with movement intensity, and the direction of the BMR-home range correlation tended to change with age of the voles. The latter result indicates that testing the theory will be particularly challenging.


Assuntos
Arvicolinae , Comportamento de Retorno ao Território Vital , Animais , Metabolismo Basal , Metabolismo Energético , Fenótipo
20.
J Vis Exp ; (160)2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32597870

RESUMO

Neurospheres are primary cell aggregates that comprise neural stem cells and progenitor cells. These 3D structures are an excellent tool to determine the differentiation and proliferation potential of neural stem cells, as well as to generate cell lines than can be assayed over time. Also, neurospheres can create a niche (in vitro) that allows the modeling of the dynamic changing environment, such as varying growth factors, hormones, neurotransmitters, among others. Microtus ochrogaster (prairie vole) is a unique model for understanding the neurobiological basis of socio-sexual behaviors and social cognition. However, the cellular mechanisms involved in these behaviors are not well known. The protocol aims to obtain neural progenitor cells from the neurogenic niches of the adult prairie vole, which are cultured under non-adherent conditions, to generate neurospheres. The size and number of neurospheres depend on the region (subventricular zone or dentate gyrus) and sex of the prairie vole. This method is a remarkable tool to study sex-dependent differences in neurogenic niches in vitro and the neuroplasticity changes associated with social behaviors such as pair bonding and biparental care. Also, cognitive conditions that entail deficits in social interactions (autism spectrum disorders and schizophrenia) could be examined.


Assuntos
Arvicolinae/fisiologia , Pradaria , Neurogênese , Neurônios/citologia , Animais , Adesão Celular , Células Cultivadas , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Imageamento Tridimensional , Antígeno Ki-67/metabolismo , Masculino , Microdissecção , Proteínas Associadas aos Microtúbulos/metabolismo , Nestina/metabolismo , Neuropeptídeos/metabolismo , Esferoides Celulares/citologia
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