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1.
FEBS Open Bio ; 14(2): 241-257, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-37925593

RESUMO

Torpor or heterothermy is an energy-saving mechanism used by endotherms to overcome harsh environmental conditions. During winter, the garden dormouse (Eliomys quercinus) hibernates with multiday torpor bouts and body temperatures of a few degrees Celsius, interrupted by brief euthermic phases. This study investigates gene expression within the hypothalamus, the key brain area controlling energy balance, adding information on differential gene expression potentially relevant to orchestrate torpor. A de novo assembled transcriptome of the hypothalamus was generated from garden dormice hibernating under constant darkness without food and water at 5 °C. Samples were collected during early torpor, late torpor, and interbout arousal. During early torpor, 765 genes were differentially expressed as compared with interbout arousal. Twenty-seven pathways were over-represented, including pathways related to hemostasis, extracellular matrix organization, and signaling of small molecules. Only 82 genes were found to be differentially expressed between early and late torpor, and no pathways were over-represented. During late torpor, 924 genes were differentially expressed relative to interbout arousal. Despite the high number of differentially expressed genes, only 10 pathways were over-represented. Of these, eight were also observed to be over-represented when comparing early torpor and interbout arousal. Our results are largely consistent with previous findings in other heterotherms. The addition of a transcriptome of a novel species may help to identify species-specific and overarching torpor mechanisms through future species comparisons.


Assuntos
Hibernação , Myoxidae , Torpor , Animais , Hibernação/genética , Myoxidae/genética , Torpor/genética , Encéfalo , Perfilação da Expressão Gênica
2.
Exp Appl Acarol ; 91(1): 1-27, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37553534

RESUMO

Trombiculid mites were collected from the edible dormouse (Glis glis) within the Carpathian-Balkan distribution gradient of host species. Representatives of five genera (Leptotrombidium, Neotrombicula, Brunehaldia, Hirsutiella, Schoutedenichia) and 10 species of chiggers were discovered in the material, based on morphological and/or molecular data. Brunehaldia, new to the fauna of Greece, was recorded for the first time from the edible dormouse. Neotrombicula talmiensis was new to the fauna of Greece and Neotrombicula vulgaris was new to the fauna of North Macedonia. Successful amplification and sequencing of COI was carried out in relation to three genera and six species. The intraspecific variation of taxa hitherto distinguished based on morphological criteria was juxtaposed with molecular data, using the distance method and the phylogenetic approach. The molecular methods indicated wider than hitherto recognized, intraspecific morphological variation for Leptotrombidium europaeum and N. talmiensis. On the other hand, an inference limited to morphology proved to be insufficient for species delineation, which was confirmed by the relatively low identity (%) of examined COI sequences as well as the size of inter-/intraspecific K2P distance threshold. Our study provides support for integrative taxonomy that combines different sources of evidence and contributes to recognition of the scope of intraspecific variation. The high degree of hidden diversity revealed with the application of molecular tools, votes for a careful approach to the identification of chiggers. The confirmed cases of co-invasion, including the representatives of various genera (Leptotrombidium and Neotrombicula, Brunehaldia and Neotrombicula, Neotrombicula and Schoutedenichia, Hirsutiella and Schoutedenichia) additionally support the need to include all larvae found on a given host specimen in the identification process.


Assuntos
Infestações por Ácaros , Myoxidae , Doenças dos Roedores , Trombiculidae , Animais , Filogenia , Península Balcânica
3.
Oecologia ; 202(4): 641-653, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37543993

RESUMO

The hazel dormouse is predominantly an arboreal species that moves down to the ground to hibernate in the autumn in temperate parts of its distributional ranges at locations not yet well understood. The main objective of this study is to test whether environmental characteristics surrounding hazel dormouse hibernacula can be identified using high-resolution remote sensing and data collected in situ. To achieve this, remotely sensed variables, including canopy height and cover, topographic slope, sky view, solar radiation and cold air drainage, were modelled around 83 dormouse hibernacula in England (n = 62) and the Netherlands (n = 21), and environmental characteristics that may be favoured by pre-hibernating dormice were identified. Data on leaf litter depth, temperature, canopy cover and distance to the nearest tree were collected in situ and analysed at hibernaculum locations in England. The findings indicated that remotely sensed data were effective in identifying attributes surrounding the locations of dormouse hibernacula and when compared to in situ information, provided more conclusive results. This study suggests that remotely sensed topographic slope, canopy height and sky view have an influence on hazel dormice choosing suitable locations to hibernate; whilst in situ data suggested that average daily mean temperature at the hibernaculum may also have an effect. Remote sensing proved capable of identifying localised environmental characteristics in the wider landscape that may be important for hibernating dormice. This study proposes that this method can provide a novel progression from habitat modelling to conservation management for the hazel dormouse, as well as other species using habitats where topography and vegetation structure influence fine-resolution favourability.


Assuntos
Myoxidae , Animais , Ecossistema , Árvores , Temperatura , Inglaterra
4.
PLoS One ; 18(6): e0285782, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37294822

RESUMO

Factors for initiating hibernation are unknown, but the condition shares some metabolic similarities with consciousness/sleep, which has been associated with n-3 fatty acids in humans. We investigated plasma phospholipid fatty acid profiles during hibernation and summer in free-ranging brown bears (Ursus arctos) and in captive garden dormice (Eliomys quercinus) contrasting in their hibernation patterns. The dormice received three different dietary fatty acid concentrations of linoleic acid (LA) (19%, 36% and 53%), with correspondingly decreased alpha-linolenic acid (ALA) (32%, 17% and 1.4%). Saturated and monounsaturated fatty acids showed small differences between summer and hibernation in both species. The dormice diet influenced n-6 fatty acids and eicosapentaenoic acid (EPA) concentrations in plasma phospholipids. Consistent differences between summer and hibernation in bears and dormice were decreased ALA and EPA and marked increase of n-3 docosapentaenoic acid and a minor increase of docosahexaenoic acid in parallel with several hundred percent increase of the activity index of elongase ELOVL2 transforming C20-22 fatty acids. The highest LA supply was unexpectantly associated with the highest transformation of the n-3 fatty acids. Similar fatty acid patterns in two contrasting hibernating species indicates a link to the hibernation phenotype and requires further studies in relation to consciousness and metabolism.


Assuntos
Ácidos Graxos Ômega-3 , Myoxidae , Ursidae , Animais , Ácido alfa-Linolênico , Ácido Eicosapentaenoico/metabolismo , Ácidos Graxos/metabolismo , Ácido Linoleico , Myoxidae/metabolismo , Fosfolipídeos/metabolismo , Ursidae/metabolismo , Hibernação/fisiologia
5.
Physiol Biochem Zool ; 96(2): 144-152, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36921268

RESUMO

AbstractDuring multiday torpor, deep-hibernating mammals maintain a hypometabolic state where heart rate and ventilation are reduced to 2%-4% of euthermic rates. It is hypothesized that this ischemia-like condition may cause DNA damage through reactive oxygen species production. The reason for intermittent rewarming (arousal) during hibernation might be to repair the accumulated DNA damage. Because increasing ambient temperatures (Ta's) shortens torpor bout duration, we hypothesize that hibernating at higher Ta's will result in a faster accumulation of genomic DNA damage. To test this, we kept 39 male and female garden dormice at a Ta of either 5°C or 10°C and obtained tissue at 1, 4, and 8 d in torpor to assess DNA damage and recruitment of DNA repair markers in splenocytes. DNA damage in splenocytes measured by comet assay was significantly higher in almost all torpor groups than in summer euthermic groups. Damage accumulates in the first days of torpor at Ta=5°C (between days 1 and 4) but not at Ta=10°C. At the higher Ta, DNA damage is high at 24 h in torpor, indicating either a faster buildup of DNA damage at higher Ta's or an incomplete repair during arousals in dormice. At 5°C, recruitment of the DNA repair protein 53BP1 paralleled the increase in DNA damage over time during torpor. In contrast, after 1 d in torpor at 10°C, DNA damage levels were high, but 53BP1 was not recruited to the nuclear DNA yet. The data suggest a potential mismatch in the DNA damage/repair dynamics during torpor at higher Ta's.


Assuntos
Hibernação , Myoxidae , Torpor , Masculino , Feminino , Animais , Hibernação/fisiologia , Temperatura , Temperatura Corporal , Dano ao DNA
6.
Zoology (Jena) ; 157: 126075, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36758427

RESUMO

Every year, more and more discoveries of photoluminescence in different mammal species are made. The more recent cases thus far have been in duck-billed platypus (Ornithorhyncus anatinus), New World squirrels (Glaucomys spp.) and springhare (Pedetidae). Now we can add another species to the list: the garden dormouse (Eliomys quercinus), an endemic rodent to Europe, currently categorized as Near Threatened (NT) by the IUCN. The fluorescence was described and compared qualitatively in museum specimens, deceased and hibernating animals. The feet and nose of the hibernating dormouse displayed greenish-blue photoluminescence under UV light through a yellow filter, whereas the fur was bright red. The live animal had more vivid red colouring than the museum specimen. The fading and changing of the colour and brightness of photoluminescence was observed in a recently deceased animal and even more strongly in museum specimens.


Assuntos
Myoxidae , Animais , Roedores , Europa (Continente)
7.
Parasitol Int ; 94: 102740, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36804597

RESUMO

This work reports for the first time the presence and molecular characterization of Eimeria myoxi in the garden dormouse (Eliomys quercinus) from the Doñana Natural Area (Andalusia, SW Spain). Fresh faecal samples were collected from a total of 28 garden dormice, which were caught following current guidelines for the ethical use of animals in research, and processing by a standard flotation technique with saturated saline solution. Then, wet drops were examined microscopically, and the number of oocysts was semi-quantified. Eimeria oocysts were observed in 16 of the 28 (57.1%) faecal samples, showing most of them a very low number of oocysts (≤1 oocyst per microscopic field × 400). The unsporulated oocysts visualized in 16 faecal samples were subspherical and of length 19.2 ± 1.2 µm and width 17.4 ± 1.1 µm, being morphologically compatible with E. myoxi. This finding was supported by molecular analysis of the small subunit ribosomal RNA (SSU-rRNA) gene, identifying the same species in 22 of the 28 (78.6%) dormice, including 15 samples in which oocyst size was compatible with E. myoxi. Moreover, the subsequent analyses of the apicoplast open reading frame 470 (ORF470) and the mitochondrial cytochrome c oxidase subunit I (COI) genes confirmed the molecular identification of the isolates as E. myoxi. The phylogeny analyses were consistent with previous phylogenetic studies and support the existence of three lineages of rodent-infecting Eimeria species.


Assuntos
Coccidiose , Eimeria , Myoxidae , Animais , Coccidiose/epidemiologia , Coccidiose/veterinária , Myoxidae/parasitologia , Oocistos , Filogenia , Espanha/epidemiologia
8.
Animal Model Exp Med ; 5(5): 482-484, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36149253

RESUMO

Monkeypox virus can infect several animals, including squirrels, Gambian poached rats, dormice, prairie dogs, monkeys, humans, etc. As reported, about 52 015 laboratory-confirmed cases, including 18 deaths, have been reported to WHO from 102 member states across all 6 WHO regions from 1 Jan 2022 to 2 Sep 2022. WHO defined the disease as a Public Health Emergency of International Concern (PHEIC) on 21 July 2022. These data showed that monkeypox is novel global threat.


Assuntos
Myoxidae , Humanos , Animais , Vírus da Varíola dos Macacos , Sciuridae , Muridae
9.
Physiol Biochem Zool ; 95(5): 400-415, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35930826

RESUMO

AbstractHibernation, or multiday torpor, allows individuals to save energy via substantial reductions of metabolism and body temperature but is regularly interrupted by euthermic phases called arousals. Social thermoregulation, or "huddling," can act in synergy with torpor in reducing individuals' energy and heat losses. In the wild, the garden dormouse (Eliomys quercinus) combines both strategies, which are crucial for winter survival of juveniles with limited prehibernation body fat reserves. We investigated via thermographic and temperature measurements (i) the energetic impact of huddling during an arousal from deep torpor, (ii) the dynamics of huddling behavior during hibernation, and (iii) its consequences during the entire winter in juvenile garden dormice. Thermographic images revealed a significant effect of huddling on torpor energetics, as it reduced heat exchange and mass loss by two-thirds in huddling versus single individuals during arousal. Our investigation of the dynamics of huddling further revealed a "random-like mechanistic" behavior during winter hibernation, as arousals from torpor were not always initiated by the same individuals. Animals took turns in initiating rewarming within a group, and the individual with highest body temperature during arousal entered into torpor later than the others within the huddle. The animals share both costs and benefits of huddling during arousals, without any energetic benefit of huddling over the entire winter on an individual level. We conclude that the dynamics of social thermoregulation during hibernation seems to counterbalance its benefit of reducing energetic costs associated against the energy-demanding process of rewarming from torpor.


Assuntos
Hibernação , Myoxidae , Torpor , Animais , Temperatura Corporal , Regulação da Temperatura Corporal , Hibernação/fisiologia , Myoxidae/fisiologia , Estações do Ano , Torpor/fisiologia
10.
PLoS One ; 17(7): e0265156, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35793361

RESUMO

Terrestrial anurans, with their typically short limbs, heavy-set bodies and absent claws or toe pads are incongruous tree climbers, but even occasional arboreal locomotion could offer substantial advantages for evading predators or accessing new shelter or food resources. Despite recent interest, arboreal behaviour remains rarely and unsystematically described for terrestrial amphibians in Europe, likely due to fundamental differences in survey methods and therefore a lack of field data. However, other taxa surveys specifically target trees and tree cavities. We undertook collaborations and large-scale data searches with two major citizen science projects surveying for arboreal mammals in Britain to investigate potential tree climbing by amphibians at a national scale. Remarkably, we found widespread arboreal usage by amphibians in England and Wales, with occupancy of hazel dormouse (Muscardinus avellenarius) nest boxes, tree cavities investigated as potential bat roosts and even a bird nest, by common toads (Bufo bufo), but few additional records of frogs or newts. Of the 277-400 sites surveyed annually for dormice since 2009 at least 18 sites had amphibians recorded in nest boxes while of the 1388 trees surveyed for bats a total 1.4% (19 trees) had toads present. Common toads were found using cavities in seven tree species and especially goat willow (Salix caprea). Toads are potentially attracted to tree cavities and arboreal nests because they provide safe and damp microenvironments which can support an abundance of invertebrate prey but the importance of such tree microhabitats for toad conservation remains unknown and our results should be interpreted cautiously. We encourage expanding and linking of unrelated biodiversity monitoring surveys and citizen science initiatives as valuable tools for investigating ecological traits and interactions.


Assuntos
Ciência do Cidadão , Myoxidae , Animais , Anuros , Bufo bufo , Hábitos , Mamíferos , Inquéritos e Questionários , Árvores , Reino Unido
11.
Zoolog Sci ; 39(2): 193-197, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35380190

RESUMO

We conducted a quantitative dietary analysis of the Japanese dormouse (Glirulus japonicus) using fecal samples collected in the subalpine zone of the Yatsugatake Mountains, central Japan. Dormouse diets were dominated by insects (69.2%) in summer and both fruit (43.0%) and insects (33.4%) in autumn. Leaves accounted for a small proportion of the diet in all seasons. Dormice may be reliant on insects because fruits are scant in summer, and on fruits to accumulate body fat in autumn before hibernation.


Assuntos
Myoxidae , Animais , Dieta/veterinária , Comportamento Alimentar , Japão , Estações do Ano
12.
J Anat ; 240(5): 914-935, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34784427

RESUMO

Dormice are widely dispersed across various ecosystems in Eurasia and Africa and among the oldest extant rodent lineages. Despite distinct morphological variation to be present between groups, comprehensive morphometrical studies on the dormouse skull are limited. Here, the form of eight out of the nine extant dormouse genera was analysed using 3D geometric morphometrics and linear biomechanical measurements, providing a better understanding of the overall morphological variation present within Gliridae. Species-, genus- and family-specific morphological trends in both the size and shape of the cranium and mandible are linked with specific habitats and feeding strategies. Smaller dormice show adaptations to a more arboreal lifestyle such as a relatively enlarged braincase and an inferiorly reoriented foramen magnum. Larger dormice show cranial modifications, including clear flattening of the skull and a more posteriorly positioned foramen magnum, hinting towards a more rupicolous lifestyle. Furthermore, specimens inhabiting arid areas appear to have more inflated auditory bullae, whereas other variable features, such as the length of the incisive foramen, were not associated with either size changes or climatic variables. Lastly, more robust and horizontally orientated zygomatic arches as well as increased robusticity of the molar row appear to be linked with herbivory in dormice, whereas thinner arches and small concave molars are seen in more insectivorous species. This study reveals clear convergent adaptations between dormouse species and results in a better understanding of ecological drivers underpinning the morphological divergence present within Gliridae.


Assuntos
Myoxidae , Animais , Ecossistema , Cabeça , Roedores/anatomia & histologia , Crânio/anatomia & histologia
13.
J Exp Biol ; 224(23)2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34762135

RESUMO

Hibernating mammals drastically lower their rate of oxygen consumption and body temperature (Tb) for several weeks, but regularly rewarm and stay euthermic for brief periods (<30 h). It has been hypothesized that these periodic arousals are driven by the development of a metabolic imbalance during torpor; that is, the accumulation or the depletion of metabolites or the accrual of cellular damage that can be eliminated only in the euthermic state. We obtained oxygen consumption (as a proxy of metabolic rate) and Tb at 7 min intervals over entire torpor-arousal cycles in the garden dormouse (Eliomys quercinus). Torpor bout duration was highly dependent on mean oxygen consumption during the torpor bout. Oxygen consumption during torpor, in turn, was elevated by Tb, which fluctuated only slightly in dormice kept at ∼3-8°C. This corresponds to a well-known effect of higher Tb on shortening torpor bout lengths in hibernators. Arousal duration was independent from prior torpor length, but arousal mean oxygen consumption increased with prior torpor Tb. These results, particularly the effect of torpor oxygen consumption on torpor bout length, point to an hourglass mechanism of torpor control, i.e. the correction of a metabolic imbalance during arousal. This conclusion is in line with previous comparative studies providing evidence for significant interspecific inverse relationships between the duration of torpor bouts and metabolism in torpor. Thus, a simple hourglass mechanism is sufficient to explain torpor/arousal cycles, without the need to involve non-temperature-compensated circadian rhythms.


Assuntos
Hibernação , Myoxidae , Torpor , Animais , Nível de Alerta , Temperatura Corporal , Ritmo Circadiano
14.
Mol Cell Endocrinol ; 533: 111315, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34052302

RESUMO

Our knowledge of the perception of stress and its implications for animals in the wild is limited, especially in regard to mammals. The aim of this study was therefore to identify sex specific effects of reproductive activity, body mass, food availability and hibernation on stress hormone levels in the edible dormouse (Glis glis), a small mammalian hibernator. Results of our study reveal that reproductive activity and pre-hibernation fattening were associated with high cortisol levels in both sexes. During the mating season, in particular individuals with low body masses had higher stress levels. Elevated levels of cortisol during pre-hibernation fattening were even higher in females that had formerly invested into reproduction compared to non-reproductive females. Previously observed impairments on health parameters and reduced survival rates associated with reproduction emphasize the functional relevance of high stress hormone levels for fitness. Prolonged food limitation, however, did not affect stress levels demonstrating the ability of dormice to predict and cope with food restriction.


Assuntos
Hidrocortisona/metabolismo , Myoxidae/fisiologia , Animais , Feminino , Hibernação , Traços de História de Vida , Masculino , Reprodução , Caracteres Sexuais , Estresse Fisiológico
15.
J Exp Zool A Ecol Integr Physiol ; 335(4): 436-453, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33830677

RESUMO

Arboreal mammals have evolved a range of biomechanical adaptations that allow them to navigate trees effectively. One such feature that has received considerable attention is the importance of vision that helps arboreal animals assess gap distances, assure proper foot placement, and inspect potential risks. While there is considerable debate about the relative importance of the visual system specifics, there is little doubt that the ability to at least see the environment must confer some level of safety when navigating arboreal substrates. In this study, we explore spatiotemporal and kinematic patterns of arboreal locomotion in the Vietnamese pygmy dormouse (Typhlomys chapensis), a blind rodent that uses ultrasonic echolocation to navigate in tree canopies. We compare these data with five other species of arboreal rodents and primates. Spatiotemporal gait characteristics are largely similar between the Vietnamese pygmy dormouse and other small-bodied arboreal species analyzed. Most notable is the tendency for relatively high-speed asymmetrical gaits on large-diameter substrates and slower symmetrical lateral-sequence gaits on small-diameter substrates. Furthermore, for all species speed is primarily regulated by increasing stride frequency rather than length. Kinematics of the Vietnamese pygmy dormouse changed little in response substrate size and were primarily driven by speed. These findings suggest that the information gathered during ultrasonic scanning is sufficient to allow effective quadrupedal locomotion while moving on arboreal supports. The Vietnamese pygmy dormouse may serve as a model for the quadrupedal nocturnal ancestor of bats, which had started developing ultrasonic echolocation and reducing vision while likely occupying an arboreal niche.


Assuntos
Ecolocação/fisiologia , Marcha/fisiologia , Myoxidae/fisiologia , Primatas/fisiologia , Animais , Membro Anterior/fisiologia , Membro Posterior/fisiologia , Masculino , Análise Espaço-Temporal , Especificidade da Espécie , Árvores
16.
Proc Biol Sci ; 287(1938): 20202085, 2020 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-33143584

RESUMO

Insular gigantism-evolutionary increases in body size from small-bodied mainland ancestors-is a conceptually significant, but poorly studied, evolutionary phenomenon. Gigantism is widespread on Mediterranean islands, particularly among fossil and extant dormice. These include an extant giant population of Eliomys quercinus on Formentera, the giant Balearic genus †Hypnomys and the exceptionally large †Leithia melitensis of Pleistocene Sicily. We quantified patterns of cranial and mandibular shape and their relationships to head size (allometry) among mainland and insular dormouse populations, asking to what extent the morphology of island giants is explained by allometry. We find that gigantism in dormice is not simply an extrapolation of the allometric trajectory of their mainland relatives. Instead, a large portion of their distinctive cranial and mandibular morphology resulted from the population- or species-specific evolutionary shape changes. Our findings suggest that body size increases in insular giant dormice were accompanied by the evolutionary divergence of feeding adaptations. This complements other evidence of ecological divergence in these taxa, which span predominantly faunivorous to herbivorous diets. Our findings suggest that insular gigantism involves context-dependent phenotypic modifications, underscoring the highly distinctive nature of island faunas.


Assuntos
Evolução Biológica , Myoxidae/fisiologia , Adaptação Fisiológica , Animais , Tamanho Corporal , Fósseis
17.
Sci Rep ; 10(1): 20323, 2020 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-33230252

RESUMO

Experimental studies suggest involvement of trimethylamine N-oxide (TMAO) in the aetiology of cardiometabolic diseases and chronic kidney disease (CKD), in part via metabolism of ingested food. Using a comparative biomimetic approach, we have investigated circulating levels of the gut metabolites betaine, choline, and TMAO in human CKD, across animal species as well as during hibernation in two animal species. Betaine, choline, and TMAO levels were associated with renal function in humans and differed significantly across animal species. Free-ranging brown bears showed a distinct regulation pattern with an increase in betaine (422%) and choline (18%) levels during hibernation, but exhibited undetectable levels of TMAO. Free-ranging brown bears had higher betaine, lower choline, and undetectable TMAO levels compared to captive brown bears. Endogenously produced betaine may protect bears and garden dormice during the vulnerable hibernating period. Carnivorous eating habits are linked to TMAO levels in the animal kingdom. Captivity may alter the microbiota and cause a subsequent increase of TMAO production. Since free-ranging bears seems to turn on a metabolic switch that shunts choline to generate betaine instead of TMAO, characterisation and understanding of such an adaptive switch could hold clues for novel treatment options in burden of lifestyle diseases, such as CKD.


Assuntos
Biomimética/métodos , Hibernação/fisiologia , Metilaminas/sangue , Insuficiência Renal Crônica/sangue , Ursidae/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Betaína/sangue , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/mortalidade , Colina/sangue , Feminino , Microbioma Gastrointestinal , Humanos , Leões/sangue , Masculino , Pessoa de Meia-Idade , Myoxidae/sangue , Estudos Prospectivos , Insuficiência Renal Crônica/complicações , Sus scrofa/sangue , Tigres/sangue
18.
Behav Processes ; 177: 104141, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32445854

RESUMO

Nest sharing in rodents and other vertebrates is believed to be promoted by the gain of thermoregulatory advantages, reproductive imperatives or to be a by-product of other benefits to group living. Here, we studied the patterns of nest box sharing over a yearly cycle in a wild population of the arboreal, nocturnal and heterothermic woodland dormouse (Graphiurus murinus). We evaluated whether the timing of dormouse aggregations and group composition were compatible with thermoregulatory or reproductive imperatives. Nest box sharing between two or more dormice was observed throughout the year and was not correlated with monthly minimum temperatures. Therefore, the observed aggregations could not be exclusively related to the gain of a thermoregulatory advantage. All-male and all-female aggregations were more frequent during the mating season, following which some females seemed to engage in communal nesting and continued to share nests with some of their offspring well beyond the weaning period. Our data suggest that nest sharing was only partly affected by basic reproductive needs. We hypothesize that dormouse aggregations were ultimately favoured by a high level of intra-sexual tolerance elicited by the presence of numerous kin-related and familiar individuals in the population. This seems to stem from the high inter-individual spatial overlaps and the promiscuous mating system previously reported in this species. Further studies focusing on natural resting sites and genetic relatedness between individuals are needed to confirm our findings and test our hypothesis.


Assuntos
Myoxidae , Animais , Feminino , Florestas , Masculino , Comportamento de Nidação , Reprodução , Comportamento Sexual
19.
Cells ; 9(4)2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32340154

RESUMO

Satellite cells (SCs) participate in skeletal muscle plasticity/regeneration. Activation of SCs implies that nuclear changes underpin a new functional status. In hibernating mammals, periods of reduced metabolic activity alternate with arousals and resumption of bodily functions, thereby leading to repeated cell deactivation and reactivation. In hibernation, muscle fibers are preserved despite long periods of immobilization. The structural and functional characteristics of SC nuclei during hibernation have not been investigated yet. Using ultrastructural and immunocytochemical analysis, we found that the SCs of the hibernating edible dormouse, Glis glis, did not show apoptosis or necrosis. Moreover, their nuclei were typical of quiescent cells, showing similar amounts and distributions of heterochromatin, pre-mRNA transcription and processing factors, as well as paired box protein 7 (Pax7) and the myogenic differentiation transcription factor D (MyoD), as in euthermia. However, the finding of accumulated perichromatin granules (i.e., sites of storage/transport of spliced pre-mRNA) in SC nuclei of hibernating dormice suggested slowing down of the nucleus-to-cytoplasm transport. We conclude that during hibernation, SC nuclei maintain similar transcription and splicing activity as in euthermia, indicating an unmodified status during immobilization and hypometabolism. Skeletal muscle preservation during hibernation is presumably not due to SC activation, but rather to the maintenance of some functional activity in myofibers that is able to counteract muscle wasting.


Assuntos
Ciclo Celular , Núcleo Celular/metabolismo , Hibernação , Modelos Biológicos , Células Satélites de Músculo Esquelético/citologia , Animais , Heterocromatina/metabolismo , Masculino , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/ultraestrutura , Myoxidae , Células Satélites de Músculo Esquelético/ultraestrutura
20.
J Therm Biol ; 88: 102510, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32125991

RESUMO

Phenotypic plasticity is crucial for how organisms respond to variation in their environment, affecting their diversity and distribution, especially in the light of rapid environmental change. Ecogeographical rules predict an association between specific adaptive morphological and physiological traits with cooler conditions due to higher latitude, elevation, or climate change. Such ecogeographical effects are often most evident in ancient species due to continuous selective adaptation occurring over long periods of time. Here, we use the suitably ancient Chinese pygmy dormouse (Typhlomys cinereus) to test whether body-size, appendage length and heart size vary in accordance with Bergmann's, Allen's and Hesse's rule, respectively. Based on a sample of 67 adult individuals (female, n = 29; male n = 38) trapped at 37 sites transcending an elevational range from 414 to 1757 m, we tested for trait concordance with Bergmann's rule (body mass, length and SMI), Allen's rule (length of tail, foot, ear, snout), and Hesse's rule (wet and dry heart mass). Effects of elevation (and thus temperature lapse rate; calculated as 0.61 °C per 100 m) on body size, appendage length and heart size, were tested by fitting Standardized Major Axis (SMA) models. We observed substantial heterogeneity in morphometric traits allowing for the detection of ecogeographical clines. However, none conformed with Bergmann's, Allen's (except ear size), or Hesse's rule. However, our results indicate some support for Geist's rule of net primary productivity. We conclude that pervasive functional life-history adaptations in this blind, arboreal, echolocating ancient species exceeded selection for morphological energy efficiency constraints, with the notable exception of reduced ear pinnae size at colder, elevated sites. This is an important consideration for predicting how species, and populations in general, may adapt to human induced rapid environmental change, contrary to expectations of warming driving selection for smaller body-size.


Assuntos
Tamanho Corporal/fisiologia , Myoxidae/fisiologia , Temperatura , Aclimatação , Animais , Mudança Climática , Feminino , Coração/anatomia & histologia , Masculino , Tamanho do Órgão
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