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1.
Parasitol Res ; 119(5): 1553-1562, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32236709

RESUMO

We confirm the presence of nymphs of the introduced pentastomid, Linguatula serrata, in the introduced rabbit, Oryctolagus cuniculus, in Australia, based on morphological and molecular results. Two nymphs were collected from a single rabbit near the Kosciuszko National Park in New South Wales. Unlike reports of nymphs from domestic animals, these nymphs were not encapsulated, despite having the morphological features of infective nymphs. The possibility of different development pathways in lagomorphs is discussed. Examination of feral deer for L. serrata was unsuccessful and potential reasons for a lack of infection in these animals are postulated. Our results reiterate the need for a combined morphological and molecular approach to the identification of L. serrata. Further sampling of a range of feral and native animals is required to determine the true range of intermediate hosts and their relative importance in the transmission of L. serrata in Australia.


Assuntos
Especificidade de Hospedeiro/fisiologia , Lagomorpha/parasitologia , Doenças Parasitárias em Animais/parasitologia , Pentastomídeos/crescimento & desenvolvimento , Animais , Austrália/epidemiologia , Cervos/parasitologia , New South Wales/epidemiologia , Ninfa/crescimento & desenvolvimento , Doenças Parasitárias em Animais/epidemiologia , Prevalência , Coelhos
2.
PLoS One ; 14(12): e0226202, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31830084

RESUMO

The plethora of restriction factors with the ability to inhibit the replication of retroviruses have been widely studied and genetic hallmarks of evolutionary selective pressures in Primates have been well documented. One example is the tripartite motif-containing protein 5 alpha (TRIM5α), a cytoplasmic factor that restricts retroviral infection in a species-specific fashion. In Lagomorphs, similarly to what has been observed in Primates, the specificity of TRIM5 restriction has been assigned to the PRYSPRY domain. In this study, we present the first insight of an intra-genus variability within the Lagomorpha TRIM5 PRYSPRY domain. Remarkably, and considering just the 32 residue-long v1 region of this domain, the deduced amino acid sequences of Daurian pika (Ochotona dauurica) and steppe pika (O. pusilla) evidenced a high divergence when compared to the remaining Ochotona species, presenting values of 44% and 66% of amino acid differences, respectively. The same evolutionary pattern was also observed when comparing the v1 region of two Sylvilagus species members (47% divergence). However, and unexpectedly, the PRYSPRY domain of Lepus species exhibited a great conservation. Our results show a high level of variation in the PRYSPRY domain of Lagomorpha species that belong to the same genus. This suggests that, throughout evolution, the Lagomorpha TRIM5 should have been influenced by constant selective pressures, likely as a result of multiple different retroviral infections.


Assuntos
Evolução Molecular , Especiação Genética , Lagomorpha/genética , Primatas/genética , Proteínas com Motivo Tripartido/genética , Sequência de Aminoácidos , Animais , Lagomorpha/metabolismo , Filogenia , Primatas/metabolismo , Domínios Proteicos , Homologia de Sequência , Especificidade da Espécie , Proteínas com Motivo Tripartido/metabolismo
3.
Microb Biotechnol ; 12(5): 976-992, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31380612

RESUMO

Despite their important roles in host nutrition, metabolism and adaptability, the knowledge on how the mammalian gut microbial community assemble is relatively scanty, especially regarding the ecological mechanisms that govern microbiota along environmental gradients. To address this, we surveyed the diversity, function and ecological processes of gut microbiota in the wild plateau pika, Ochotona curzoniae, along the elevational gradient from 3106 to 4331 m on 'the Roof of the World'-Qinghai-Tibet Plateau. The results indicated that the alpha, beta and functional diversity of gut microbiota significantly increased with elevation, and elevation significantly explained the variations in the gut microbial communities, even after controlling for geographical distance, host sex and body weight. Some gene functions (e.g. nitrogen metabolism and protein kinases) associated with metabolism were enriched in the high-altitude pikas. Null model and phylogenetic analysis suggest that the relative contributions of environmental filtering responsible for local gut communities increased with elevation. In addition, deterministic processes dominated gut microbial communities in the high-altitude (more than 3694 m) pikas, while the percentages of stochastic and deterministic processes were very close in the low-altitude (3106 and 3580 m) pikas. The observed mechanisms that influence pika gut microbiota assembly and function seemed to be mainly mediated by the internal gut environment and by the external environmental pressure (i.e. lower temperature) in the harsh high-altitude environment. These findings enhance our understanding of gut microbiota assembly patterns and function in wild mammals from extreme harsh environments.


Assuntos
Exposição Ambiental , Microbioma Gastrointestinal , Lagomorpha/microbiologia , Animais , Geografia , Redes e Vias Metabólicas/genética , Filogenia , Tibet
4.
Dokl Biol Sci ; 486(1): 83-85, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31317451

RESUMO

Leporid fossils from the Lower Pleistocene deposits of the Taurida karstic cave discovered in 2018 in central Crimea (Zuya village, Belogorsk district) are referred to Hypolagus brachygnathus (Kormos, 1930). This species is characteristic of the interval from the early Pleistocene (late Villanyian, MN17) to the middle Pleistocene (latest Biharian, Q2) of Europe. It has not been previously observed in Crimea.


Assuntos
Fósseis/anatomia & histologia , Lagomorpha/anatomia & histologia , Animais , Cavernas , Maxila/anatomia & histologia , Dente/anatomia & histologia
5.
Environ Sci Technol ; 53(16): 9472-9480, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31310123

RESUMO

Little is currently known about the trophic transfer behavior of short-chain chlorinated paraffins (SCCPs) in terrestrial ecosystems. The trophodynamics of SCCPs were investigated in a typical terrestrial food chain (plant-plateau pika-eagle) from the interior of the Tibetan Plateau with an altitude of 4730 m. Pervasive contamination by SCCPs was found in the Tibetan Plateau samples, and the average concentrations of SCCPs in soil, plant, plateau pika, eagle, and gut content of eagle samples were 81.6 ± 31.1, 173 ± 70.3, 258 ± 126, 108 ± 59.6, and 268 ± 93.9 ng/g (average ± standard deviation, dry weight, dw), respectively. The trophic magnification factor (TMF) of SCCPs was 0.37, implying the trophic dilution of SCCPs in this terrestrial food chain. The TMF values of individual congener groups were positively correlated with the values of log Kow, log Koa and biotransformation half-life. As a result of long-range transport, SCCPs congeners with low molecular weight dominated in Tibetan Plateau species (C10+11 congeners = 76.9%, Cl5+6+7 congeners = 71.5%), which could partly explain the low biomagnification factors (BMFs) of SCCPs in the Tibetan Plateau.


Assuntos
Águias , Hidrocarbonetos Clorados , Lagomorpha , Animais , China , Ecossistema , Monitoramento Ambiental , Cadeia Alimentar , Parafina , Tibet
6.
Int J Syst Evol Microbiol ; 69(8): 2305-2311, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31162020

RESUMO

Three independent isolates (10022T, 10 009 and 10011) of a novel catalase-positive, Gram-stain-negative coccus in the genus Neisseria were obtained from the rectal contents of plateau pika on the Qinghai-Tibet Plateau, PR China. Based on 16S rRNA gene sequence analysis, our newly identified organisms were most closely related to Neisseria iguanae, Neisseria flavescens and Neisseria perflava with similarities ranging from 98.02 to 98.45 %, followed by seven other species in the genus Neisseria. Phylogenetic analysis based on 16S rRNA and rplF genes showed that our three novel isolates group with members of the genus Neisseria. Results of the average nucleotide identity (ANI) analysis confirmed that our isolates are of the same species, and the ANI values between type strain 10022T and other Neisseria species are 74.12-85.06 %, lower than the threshold range of 95-96 %. The major cellular fatty acids for our novel species are C16 : 0 and C16:1ω7c/C16:1ω6c, which along with their phenotypic characteristics can distinguish our isolates from other Neisseria species. On the basis of polyphasic analyses, our isolates are proposed to represent a novel species in genus Neisseria, with the name Neisseria weixii sp. nov. The type strain is 10022T (=DSM 103441T=CGMCC 1.15732T).


Assuntos
Lagomorpha/microbiologia , Neisseria/classificação , Filogenia , Reto/microbiologia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Neisseria/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tibet
7.
Am Nat ; 193(6): 786-797, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31094601

RESUMO

Species' geographic distributions have already shifted during the Anthropocene. However, we often do not know what aspects of the environment drive range dynamics, much less which traits mediate organisms' responses to these environmental gradients. Most studies focus on possible climatic limits to species' distributions and have ignored the role of biotic interactions, despite theoretical support for their importance in setting distributional limits. We used field experiments and simulations to estimate contributions of mammalian herbivory to a range boundary in the Californian annual plant Clarkia xantiana ssp. xantiana. A steep gradient of increasing probability of herbivory occurred across the boundary, and a reanalysis of prior transplant experiments revealed that herbivory drove severalfold declines in lifetime fitness at and beyond the boundary. Simulations showed that populations could potentially persist beyond the range margin in the absence of herbivory. Using data from a narrowly sympatric subspecies, Clarkia xantiana parviflora, we also showed that delayed phenology is strongly associated with C. xantiana ssp. xantiana's susceptibility to herbivory and low fitness beyond its border. Overall, our results provide some of the most comprehensive evidence to date of how the interplay of demography, traits, and spatial gradients in species interactions can produce a geographic range limit, and they lend empirical support to recent developments in range limits theory.


Assuntos
Clarkia , Ecossistema , Aptidão Genética , Herbivoria , Lagomorpha , Animais , California , Geografia
8.
Vet Parasitol Reg Stud Reports ; 16: 100279, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31027609

RESUMO

Greece is an endemic country for human and canine leishmaniosis. Studies about the role of lagomorphs and minks in the epidemiology of the diseases are, so far, limited. The aim of the present study was to investigate the prevalence of Leishmania infection in these animals, in different areas of the country. Samples from 393 domestic and wild rabbits, 90 hares and 200 minks were collected and examined by cytology (spleen imprints) and serology (ELISA), while spleen samples of 116, 56 and 95 of the rabbits, hares and minks, respectively, were examined by a PCR assay targeting the ITS1 region. For every animal examined a form was created, recording information like date, area, animal species, sex, etc. All imprint smears examined were negative, while serology revealed infection in 7.6% (C.I. 5.0-10.3%) rabbits, 6.7% (C.I. 1.5-11.8%) hares and 20% (C.I. 14.5-25.5%) minks. Infection was confirmed by molecular methods in 2.6% (C.I. 0.0-5.5%), 3.6% (C.I. 0.0-8.4%) and 2.1% (C.I. 0.0-5.0%) of the animals, respectively. The statistical analysis showed that minks are most likely to be seropositive and that in rabbits, the breeding method (i.e. homestead reared animals) was associated with infection. Because of the proximity of lagomorphs and minks to humans and dogs it is necessary to further elucidate their role in the epidemiology of leishmaniosis.


Assuntos
Lagomorpha/parasitologia , Leishmaniose/veterinária , Vison/parasitologia , Animais , Animais Domésticos , Animais Selvagens , Anticorpos Antiprotozoários/sangue , Intervalos de Confiança , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Grécia/epidemiologia , Leishmania/genética , Leishmania/imunologia , Leishmania/isolamento & purificação , Leishmaniose/epidemiologia , Masculino , Reação em Cadeia da Polimerase/veterinária , Prevalência , Coelhos , Baço/parasitologia
9.
Immunogenetics ; 71(5-6): 437-443, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30874861

RESUMO

Toll-like receptors (TLRs) are one of the first lines of defense against pathogens and are crucial for triggering an appropriate immune response. Among TLRs, TLR2 is functional in all vertebrates and has high ability in detecting bacterial and viral pathogen ligands. The mammals' phylogenetic tree of TLR2 showed longer branches for the Lagomorpha clade, raising the hypothesis that lagomorphs experienced an acceleration of the mutation rate. This hypothesis was confirmed by (i) Tajima's test of neutrality that revealed different evolutionary rates between lagomorphs and the remaining mammals with lagomorphs presenting higher nucleotide diversity; (ii) genetic distances were similar among lagomorphs and between lagomorphs and other mammals; and (iii) branch models reinforced the existence of an acceleration of the mutation rate in lagomorphs. These results suggest that the lagomorph TLR2 has been strongly involved in pathogen recognition, which probably caused a host-pathogen arms race that led to the observed acceleration of the mutation rate.


Assuntos
Evolução Molecular , Lagomorpha/genética , Mamíferos/genética , Fases de Leitura Aberta , Seleção Genética , Receptor 2 Toll-Like/genética , Animais , Lagomorpha/classificação , Mutação , Taxa de Mutação , Filogenia
10.
Ecology ; 100(4): e02638, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30710338

RESUMO

Although increased frequency of extreme-weather events is one of the most secure predictions associated with contemporary climate change, effects of such events on distribution and abundance of climate-sensitive species remain poorly understood. Montane ecosystems may be especially sensitive to extreme weather because of complex abiotic and biotic interactions that propagate from climate-driven reductions in snowpack. Snowpack not only protects subnivean biotas from extreme cold, but also influences forage availability through timing of melt-off and water availability. We related relative abundances of an alpine mammal, the American pika (Ochotona princeps), to measures of weather and snowpack dynamics over an 8-yr period that included before and after a year of record-low snowpack in Washington, USA. We sought to (1) quantify any change in pika abundance associated with the snowpack anomaly and (2) identify aspects of weather and snowpack that influenced abundance of pikas. Pikas showed a 1-yr lag response to the snowpack anomaly and exhibited marked declines in abundance at elevations below 1,400 m simultaneous with increased abundances at higher elevations. Atmospheric moisture, indexed by vapor pressure deficit (VPD), was especially important, evidenced by strong support for the top-ranked model that included the interaction of VPD with snowpack duration. Notably, our novel application of VPD from gridded climate data for analyses of animal abundances shows strong potential for improving species distribution models because VPD represents an important aspect of weather that influences the physiology and habitat of biota. Pikas were apparently affected by cold stress without snowpack at mid elevations, whereas changes to forage associated with snowpack and VPD were influential at high and low elevations. Our results reveal context dependency in pika responses to weather and illustrate how snow drought can lead to rapid change in the abundance of subnivean animals.


Assuntos
Ecossistema , Lagomorpha , Animais , Mudança Climática , Ecologia , Washington
11.
BMC Evol Biol ; 19(1): 59, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30786851

RESUMO

BACKGROUND: The C-C motif chemokine ligand 16 (CCL16) is a potent pro-inflammatory chemokine and a chemoattractant for monocytes and lymphocytes. In normal plasma, it is present at high concentrations and elicits its effects on cells by interacting with cell surface chemokine receptors. In the European rabbit and in rodents such as mouse, rat and guinea pig, CCL16 was identified as a pseudogene, while in the thirteen-lined ground squirrel it appears to be potentially functional. To gain insight into the evolution of this gene in the superorder Glires (rodents and lagomorphs), we amplified the CCL16 gene from eleven Leporidae and seven Ochotonidae species. RESULTS: We compared our sequences with CCL16 sequences of twelve rodent species retrieved from public databases. The data show that for all leporid species studied CCL16 is a pseudogene. This is primarily due to mutations at the canonical Cys Cys motif, creating either premature stop codons, or disrupting amino acid replacements. In the Mexican cottontail, CCL16 is pseudogenized due to a frameshift deletion. Additionally, in the exon 1 (signal peptide), there are frameshift deletions present in all leporids studied. In contrast, in Ochotona species, CCL16 is potentially functional, except for an allele in Hoffmann's pika. In rodents, CCL16 is functional in a number of species, but patterns of pseudogenization similar to those observed in lagomorphs also exist. CONCLUSIONS: Our results suggest that while functional in the Glires ancestor, CCL16 underwent pseudogenization in some species. This process occurred stochastically or in specific lineages at different moments in the evolution of Glires. These observations suggest that the CCL16 had different evolutionary constrains in the Glires group that could be associated with the CCL16 biological function.


Assuntos
Quimiocinas/genética , Evolução Molecular , Lagomorpha/genética , Pseudogenes/genética , Roedores/genética , Sequência de Aminoácidos , Animais , Quimiocinas/química , Éxons , Humanos , Ligantes , Filogenia
12.
Antonie Van Leeuwenhoek ; 112(7): 1001-1010, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30798492

RESUMO

Two Gram-stain negative, catalase positive, coccus shaped bacteria, designated 10023T and 10010, were isolated from the rectal contents of a plateau pika (Ochotona curzoniae) in Qinghai-Tibet Plateau, China. Based on 16S rRNA gene sequence analysis, phylogenetic trees showed that these two isolates (10023T, 10010) group with members of the genus Neisseria. Additionally, these two isolates exhibited high 16S rRNA gene sequence similarity with Neisseria zalophi CSL 7565T (96.98%), Neisseria wadsworthii WC 05-9715T (96.92%) and Neisseria canis ATCC 14687T (96.79%). Further phylogenetic analysis based on the rplF gene showed that these two novel strains can be easily discriminated from phylogenetically closely related species. Optimal growth was found to occur on BHI agar with 5% defibrinated sheep blood at 37 °C and growth was also observed on nutrient agar, Columbia blood agar and chocolate agar plates; however, growth was not observed on MacConkey agar after 7 days. The major cellular fatty acids of these strains were identified as C16:0 and C16:1ω7c/C16:1ω6c. The complete genome size of the type strain 10023T is 2,496,444 bp, with DNA G+C content of 54.0 mol %. The average nucleotide identity values were 73.5-79.3% between isolate 10023T and reference Neisseria spp. Based on polyphasic analysis, these isolates (10023T and 10010) are considered to represent a novel species in the genus Neisseria, for which the name Neisseria chenwenguii sp. nov. is proposed. The type strain is 10023T (= DSM 103440T = CGMCC 1.15736T).


Assuntos
Lagomorpha/microbiologia , Neisseria/isolamento & purificação , Reto/microbiologia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Neisseria/classificação , Neisseria/genética , Neisseria/metabolismo , Filogenia , RNA Ribossômico 16S/genética , Tibet
13.
Dev Comp Immunol ; 92: 99-104, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30339876

RESUMO

This review presents some examples of studies using the European rabbit (Oryctolagus cuniculus) that have led to, and continue to, contribute to advancement of understanding of human diseases as well as therapeutics development. In addition, we tabulate FDA-approved rabbit polyclonal and rabbit monoclonal antibodies (mAbs) that are used for diagnostic applications, as well as an overview of some "humanized" or otherwise altered rabbit mAbs that are in initial phase I, II, or advanced to phase III clinical trials. Information about endogenous retriviruses learned from studies of rabbits and other members of the order Lagomorpha are summarized as this knowledge now applies to new therapeutics being developed for several human diseases including Multiple Sclerosis, Type 1 Diabetes and Cancer.


Assuntos
Diabetes Mellitus Tipo 1/imunologia , Esclerose Múltipla/imunologia , Neoplasias/imunologia , Coelhos , Animais , Ensaios Clínicos como Assunto , Modelos Animais de Doenças , Humanos , Lagomorpha , Estados Unidos , United States Food and Drug Administration
14.
Parasitology ; 146(5): 653-661, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30430954

RESUMO

The ß-diversity of fleas parasitic on small mammals in 45 regions of the Palearctic was partitioned into species [species contributions to ß-diversity (SCBD)] and site ( = assemblage) contributions [local contributions to ß-diversity (LCBD)]. We asked what are the factors affecting SCBD and LCBD and tested whether (a) variation in ecological, morphological, life history and geographic traits of fleas can predict SCBD and (b) variation in flea and host community metrics, off-host environmental factors, host species composition of flea assemblages can predict LCBD. We used spatial variables to describe geographic distribution of flea assemblages with various LCBD values. SCBD significantly increased with an increase in abundance and a decrease in phylogenetic host specificity of a flea as well as with size and latitude of its geographic range, but was not associated with any morphological/life history trait. LCBD of flea assemblages did not depend on either flea or host species richness or environmental predictors, but was significantly affected by compositional uniqueness ( = LCBD) of regional host assemblages and variables describing their species composition. In addition, variation in LCBD was also explained by broad-to-moderate-scale spatial variables. We conclude that SCBD of fleas could be predicted via their ecological and geographic traits, whereas LCBD of their assemblages could be predicted via host composition.


Assuntos
Biodiversidade , Infestações por Pulgas/veterinária , Insetívoros , Lagomorpha , Roedores , Sifonápteros/fisiologia , África do Norte/epidemiologia , Distribuição Animal , Animais , Ásia/epidemiologia , Europa (Continente)/epidemiologia , Infestações por Pulgas/epidemiologia , Infestações por Pulgas/parasitologia , Interações Hospedeiro-Parasita
15.
J Anim Ecol ; 88(3): 363-375, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30449046

RESUMO

Contemporary climate change is altering temperature profiles across the globe. Increasing temperatures can reduce the amount of time during which conditions are suitable for animals to engage in essential activities, such as securing food. Behavioural plasticity, the ability to alter behaviour in response to the environment, may provide animals with a tool to adjust to changes in the availability of suitable thermal conditions. The extent to which individuals can alter fitness-enhancing behaviours, such as food collection, to proximately buffer variation in temperature, however, remains unclear. Even less well understood are the potential performance advantages of flexible strategies among endotherms. We examined the degree to which individuals altered rates of food collection in response to temperature, and two potential benefits, using the American pika (Ochotona princeps), a temperature-sensitive, food-hoarding mammal, as a model. From July-September 2013-2015, we used motion-activated cameras and in situ temperature loggers to examine pika food-caching activity for 72 individuals across 10 sites in the central Rocky Mountains, USA. We quantified % nitrogen by cache volume as a metric of cache quality, and the number of events during which pikas were active in temperatures ≥25°C as a measure of potential thermoregulatory stress. We found a strong negative effect of temperature on the rate at which pikas cached food. Individual responses to temperature varied substantially in both the level of food-collecting activity and in the degree to which individuals shifted activity with warming temperature. After accounting for available foraging time, individuals that exhibited greater plasticity collected a comparable amount of nitrogen, while simultaneously experiencing fewer occasions in which temperatures eclipsed estimated thermal tolerances. By varying food-collection norms of reaction, individuals were able to plastically respond to temperature-driven reductions in foraging time. Through this increased flexibility, individuals amassed food caches of comparable quality, while minimizing exposure to potentially stressful thermal conditions. Our results suggest that, given sufficient resource quality and availability, plasticity in foraging activity may help temperature-limited endotherms adjust to climate-related constraints on foraging time.


Assuntos
Ecossistema , Lagomorpha , Animais , Mudança Climática , Temperatura
16.
Theriogenology ; 123: 74-82, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30296653

RESUMO

During evolution, animals optimize their reproductive strategies to increase offspring survival. Seasonal breeders reproduce only during certain times of the year. In mammals, reproduction is tightly controlled by hypothalamus-pituitary-gonad axis. Although pathways regulating gametogenesis in non-seasonal model species have been well established, molecular insights into seasonal reproduction are severely limited. Using the Plateau pika (Ochotona curzoniae), a small rodent animal species native to the Qinghai-Tibetan plateau, as a model, here we report that seasonal spermatogenesis is governed at the level of spermatogonial differentiation. In testis of the reproductively dormant animals, undifferentiated spermatogonia failed to differentiate and accumulated in the seminiferous tubules. RNA-seq analyses of the active and dormant testes revealed that genes modulating retinoic acid biogenesis and steriodogenesis were differentially regulated. A single injection of all-trans retinoic acid (ATRA) reinitiated spermatogenesis and inhibition the function of RA-degrading enzyme CYP26B1 for 10 days induced spermatogonial differentiation. Strikingly, testosterone injection reinitiated spermatogenesis in short day adapted animals. Testosterone provides a permissive environment of RA biogenesis and actions in testis, therefore, indirectly controls spermatogonial differentiation. Collectively, these findings provide a key mechanistic insight regarding the molecular regulation of seasonal reproduction in mammals.


Assuntos
Diferenciação Celular/fisiologia , Lagomorpha/fisiologia , Transdução de Sinais/fisiologia , Espermatogônias/fisiologia , Testosterona/fisiologia , Tretinoína/farmacologia , Animais , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Masculino , Ácido Retinoico 4 Hidroxilase/metabolismo , Estações do Ano , Tretinoína/administração & dosagem , Tretinoína/fisiologia
17.
Mol Ecol ; 28(2): 250-265, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30136323

RESUMO

Plant-herbivore interactions provide critical insights into the mechanisms that govern the spatiotemporal distributions of organisms. These interactions are crucial to understanding the impacts of climate change, which are likely to have an effect on the population dynamics of alpine herbivores. The Royle's pika (Ochotona roylei, hereafter pika) is a lagomorph found in the western Himalaya and is dependent on alpine plants that are at risk from climate change. As the main prey of many carnivores in the region, the pika plays a crucial role in trophic interactions. We examined topographical features, plant genera presence and seasonal dynamics as drivers of the plant richness in the pika's diet across an elevational gradient (2,600-4,450 m). We identified 79 plant genera in the faecal pellets of pikas, of which 89% were forbs, >60% were endemic to the Himalaya, and 97.5% of the diet plant genera identified followed the C3 photosynthetic pathway. We found that, during the premonsoon season, the number of genera in the pika's diet decreased with increasing elevation. We demonstrate that a large area of talus supports greater plant diversity and, not surprisingly, results in higher species richness in the pika's diet. However, in talus habitat with deep crevices, pikas consumed fewer plant genera suggesting they may be foraging suboptimally due to predation risk. The continued increase in global temperature is expected to have an effect on the distribution dynamics of C3 plants and consequently influence pika diet and distribution, resulting in a significant negative cascading effect on the Himalayan ecosystem.


Assuntos
Ecossistema , Cadeia Alimentar , Lagomorpha/fisiologia , Plantas/química , Altitude , Animais , Biodiversidade , Carnivoridade , Mudança Climática , Dieta , Fezes/química , Herbivoria/fisiologia , Mamíferos , Plantas/classificação , Plantas/genética , Estações do Ano , Temperatura
18.
Can J Microbiol ; 65(5): 365-376, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30566369

RESUMO

Intact Tibetan meadows provide significant defense against soil-borne pathogen dispersal. However, dramatic meadow degradation has been observed due to climate change and pika damage, but their impacts on soil-borne pathogens are still unclear. With approximately 40% of the world's population living in Tibetan Plateau and its downstream watersheds, this lack of knowledge should be of great concern. Here, we used Illumina amplicon sequencing to characterize the changes in potential human, domestic animal, plant, and zoonotic bacterial and fungal pathogens in nondegraded, desertified, and pika-burrowed meadows. The relative abundance of bacterial domestic animal pathogens and zoonotic pathogens were significantly increased by desertification. Pika burrowing significantly increased the relative abundance of bacterial human pathogens and zoonotic pathogens. The species richness and relative abundance of fungal pathogens was significantly increased by desertification and pika burrowing. Accordingly, fungal plant and animal pathogens categorized by FUNGuid significantly increased in desertified and pika-burrowed meadows. Soil chemical and plant properties explained 38% and 64% of the bacterial and fungal pathogen community variance, respectively. Therefore, our study indicates for the first time that both alpine meadow desertification and pika burrowing could potentially increase infectious disease risks in the alpine ecosystem, especially for fungal diseases.


Assuntos
Doenças Transmissíveis/microbiologia , Fungos , Pradaria , Lagomorpha/microbiologia , Doenças das Plantas/microbiologia , Plantas/microbiologia , Microbiologia do Solo , Animais , Mudança Climática , Ecossistema , Humanos , Medição de Risco , Solo/química , Tibet , Tundra
19.
Integr Zool ; 14(1): 87-103, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29316275

RESUMO

Understanding a species' functional traits allows for a directed and productive perspective on the role a species plays in nature, and thus its relative importance to conservation planning. The functional-trait ecology of the plateau pika Ochotona curzoniae is examined to better understand the resilience and sustainability of the high alpine grasslands of the Qinghai-Tibetan Plateau (QTP). The key functional traits of plateau pikas are their abundance and behavior of digging extensive burrow systems. Plateau pikas have been poisoned over a significant part of their original geographic distribution across the QTP, allowing comparison of ecological communities with and without pikas. Nearly all mammalian and avian carnivores, most of which are obligate predators on pikas, have been lost in regions where pikas have been poisoned. Most endemic birds on the QTP nest in pika burrows; when pikas are poisoned, burrows collapse, and these birds are greatly reduced in number. Due to the biopedturbation resulting from their burrows, regional plant species richness is higher in areas with pikas than without. The presence of pika burrows allows higher rates of infiltration during heavy monsoon rains compared to poisoned areas, possibly mitigating runoff and the potential for serious downslope erosion and flooding. Thus, the functional traits of plateau pikas enhance native biodiversity and other important ecosystem functions; these traits are irreplaceable. As plateau pikas are not natural colonizers, active re-introduction programs are needed to restore pikas to areas from which they have been poisoned to restore the important functional ecological traits of pikas.


Assuntos
Altitude , Biodiversidade , Cadeia Alimentar , Pradaria , Lagomorpha/fisiologia , Animais , Controle de Pragas , Tibet
20.
PLoS One ; 13(12): e0207936, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30540800

RESUMO

Species are shifting their ranges due to climate change, many moving to cooler and higher locations. However, with elevation increase comes oxygen decline, potentially limiting a species' ability to track its environment depending on what mechanisms it has available to compensate for hypoxic stress. Pikas (Family Ochotonidae), cold-specialist small mammal species, are already undergoing elevational range shifts. We collected RNA samples from one population of Ochotona roylei in the western Himalaya at three sites- 3,600, 4,000, and 5,000 meters-and found no evidence of significant population genetic structure nor positive selection among sites. However, out of over 10,000 expressed transcripts, 26 were significantly upregulated at the 5,000 m site and were significantly enriched for pathways consistent with physiological compensation for limited oxygen. These results suggest that differences in gene expression may play a key role in enabling hypoxia tolerance on this local scale, indicating elevational flexibility that may facilitate successful range shifts in response to climate change.


Assuntos
Hipóxia/genética , Lagomorpha/genética , Altitude , Animais , Mudança Climática , Ecossistema , Expressão Gênica/genética , Genética Populacional/métodos , Índia , Oxigênio/metabolismo , Tibet
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