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The European Journal of Neuroscience Feb 2024Besides regulating the amount of light that reaches the retina, fluctuations in pupil size also occur in isoluminant conditions during accommodation, during movement and...
Besides regulating the amount of light that reaches the retina, fluctuations in pupil size also occur in isoluminant conditions during accommodation, during movement and in relation to cognitive workload, attention and emotion. Recent studies in mammals and birds revealed that the pupils are also highly dynamic in the dark during sleep. However, despite exhibiting similar sleep states (rapid eye movement [REM] and non-REM [NREM] sleep), wake and sleep state-dependent changes in pupil size are opposite between mammals and birds, due in part to differences in the type (striated vs. smooth) and control of the iris muscles. Given the link between pupil dynamics and cognitive processes occurring during wakefulness, sleep-related changes in pupil size might indicate when related processes are occurring during sleep. Moreover, the divergent pupillary behaviour observed between mammals and birds raises the possibility that changes in pupil size in birds are a readout of processes not reflected in the mammalian pupil.
Topics: Animals; Wakefulness; Sleep; Sleep, REM; Sleep, Slow-Wave; Mammals; Electroencephalography
PubMed: 37038095
DOI: 10.1111/ejn.15983 -
PeerJ 2023Southern Mexico's tropical forests are home to the country's highest richness of mammal species; La Chinantla region is situated within this area, its name from the...
Southern Mexico's tropical forests are home to the country's highest richness of mammal species; La Chinantla region is situated within this area, its name from the indigenous group residing in the area and holding territorial ownership, namely the Chinantecos. In La Chinantla, there are no Protected Areas; instead, there are Areas Destined Voluntarily for Conservation (ADVC) and "Voluntary Conservation Areas" (VCA), that are managed by local inhabitants through social consensus. These ADVC may function as an archipelago reserve, which represents regional diversity, including the social context, through complementarity. To verify its biodiversity, we analyzed the richness, composition, distribution, and conservation of wild mammals in the region. Records were obtained from four sources-primary data collection, databases, scientific literature, and community monitoring-and were organized into four zones based on altitudinal and vegetation gradients. We compared the diversity between zones for three categories of mammals: small (<100 gr.), bats, and medium and large (>100 gr.). 134 species were identified comprising 11 orders, 26 families and 86 genera. The zone with highest elevation presented the greatest species richness for the assemblage of mammals and terrestrial mammals, while the zone with the lowest elevation had the highest richness of bats. For each mammal category, the zone with the most species also registered the highest number of exclusive species. For the assemblage of mammals and for medium and large mammals, the similarity index was highest between the two intermediate zones, while for small mammals and bats, the greatest similarity occurred between the areas of higher altitude. The study region was found to have the second highest richness of mammals in Mexico. Finally, we suggest that the conservation proposals by indigenous people could function as a set of "islands" that promote the conservation of biodiversity, possibly as an Archipelago Reserve.
Topics: Humans; Animals; Chiroptera; Mexico; Biodiversity; Mammals; Forests
PubMed: 37953770
DOI: 10.7717/peerj.16345 -
Environmental Pollution (Barking, Essex... Oct 2023Marine mammals consume large quantities of microplastic particles, likely via trophic transfer (i.e., through prey who have consumed plastic) and direct consumption from...
Marine mammals consume large quantities of microplastic particles, likely via trophic transfer (i.e., through prey who have consumed plastic) and direct consumption from seawater or sediment. Microplastics have been found in the stomachs, gastro-intestinal tracts, and feces of cetaceans and pinnipeds. Translocation of ingested microplastics has been documented in other organs of several aquatic species, but has not been examined in marine mammals. Marine mammals have highly specialized lipid-rich tissues which may increase susceptibility to lipophilic microplastics. Here we demonstrate the occurrence of microplastics, ranging in size, mass concentration, and particle count concentration from 24.4 μm - 1387 μm, 0.59 μg/g - 25.20 μg/g, and 0.04 - 0.39 particles/g, respectively, in four tissues (acoustic fat pad, blubber, lung, & melon) from twelve marine mammal species inclusive of mysticetes, odontocetes, and phocids. Twenty-two individuals were examined for microplastics using a combination of Raman spectroscopy and pyrolysis gas chromatography with mass spectrometry. Overall, 68% of individuals had at least one microplastic particle in at least one of the four tissue types, with the most common polymer and shape observed being polyethylene and fibers, respectively. These findings suggest some proportion of ingested microplastics translocate throughout marine mammal bodies posing an exposure risk to both marine mammals and people. For people, exposure could be directly through consumption for those who rely on marine mammals as food and indirectly to peoples globally who consume the same prey resources as marine mammals. Some individuals examined represent samples obtained over two decades ago, suggesting that this process, and thus exposure risk, has occurred for some time.
Topics: Animals; Microplastics; Plastics; Cucurbitaceae; Water Pollutants, Chemical; Gas Chromatography-Mass Spectrometry; Cetacea; Caniformia; Adipose Tissue; Environmental Monitoring
PubMed: 37541381
DOI: 10.1016/j.envpol.2023.122252 -
Emerging Microbes & Infections Dec 2023Powassan virus (POWV, family ) is a reemerging tick-borne virus endemic in North America and Russia. In 1997, a POWV-like agent was isolated from in New England and...
Powassan virus (POWV, family ) is a reemerging tick-borne virus endemic in North America and Russia. In 1997, a POWV-like agent was isolated from in New England and determined to be genetically distinct from the original POWV isolate. This revealed the existence of two lineages: lineage 1, prototype Powassan virus (POWV-1) and lineage 2, deer tick virus (DTV). POWV-1 is thought to be primarily maintained in a cycle between and woodchucks and and squirrels, while DTV is primarily maintained in a cycle between and small mammal hosts. Recent tick, mammalian, and human isolates from New York State (NYS) have been identified as DTV, but for the first time in 45 years, we detected four POWV-1 isolates, including the first reported isolation of POWV-1 from . We aimed to investigate genotypic and phenotypic characteristics of recent NYS isolates through sequence analysis and evaluation of replication kinetics and . Our sequencing revealed genetic divergence between NYS POWV-1 isolates, with two distinct foci. We found that POWV-1 isolates displayed variable replication kinetics in nymphal ticks but not in cell culture. POWV-1 isolated from displayed increased fitness in experimentally infected as compared to historic and recent POWV-1 isolates from . These data suggest the emergence of divergent POWV-1 strains in alternate tick hosts and maintenance of genetically and phenotypically discrete POWV-1 foci.
Topics: Animals; Humans; Ixodes; Encephalitis Viruses, Tick-Borne; New York; North America; Russia; Mammals
PubMed: 36503411
DOI: 10.1080/22221751.2022.2155585 -
Royal Society Open Science Jul 2023Dietary variation within and across species drives the eco-evolutionary responsiveness of genes necessary to metabolize nutrients and other components. Recent evidence...
Dietary variation within and across species drives the eco-evolutionary responsiveness of genes necessary to metabolize nutrients and other components. Recent evidence from humans and other mammals suggests that sugar-rich diets of floral nectar and ripe fruit have favoured mutations in, and functional preservation of, the gene, which encodes the ADH class 4 enzyme responsible for metabolizing ethanol. Here we interrogate a large, comparative dataset of gene sequence variation, including that underlying the amino acid residue located at the key site (294) that regulates the affinity of ADH7 for ethanol. Our analyses span 171 mammal species, including 59 newly sequenced. We report extensive variation, especially among frugivorous and nectarivorous bats, with potential for functional impact. We also report widespread variation in the retention and probable pseudogenization of . However, we find little statistical evidence of an overarching impact of dietary behaviour on putative function or presence of derived alleles at site 294 across mammals, which suggests that the evolution of is shaped by complex factors. Our study reports extensive new diversity in a gene of longstanding ecological interest, offers new sources of variation to be explored in functional assays in future study, and advances our understanding of the processes of molecular evolution.
PubMed: 37448478
DOI: 10.1098/rsos.230451 -
Pathogens (Basel, Switzerland) Jul 2023Rickettsiae of the spotted fever group (SFG) are zoonotic tick-borne pathogens. Small mammals are important hosts for the immature life stages of two of the most common...
Rickettsiae of the spotted fever group (SFG) are zoonotic tick-borne pathogens. Small mammals are important hosts for the immature life stages of two of the most common tick species in Europe, and . These hosts and vectors can be found in diverse habitats with different vegetation types like grasslands and forests. To investigate the influence of environmental and individual factors on prevalence, this study aimed to analyse the prevalence of SFG rickettsiae in ticks and small mammals in different small-scale habitats in central Germany for the first time. Small mammals of ten species and ticks of two species were collected from grasslands and forests in the Hainich-Dün region, central Germany. After species identification, DNA samples from 1098 ticks and ear snips of 1167 small mammals were screened for DNA by qPCR targeting the gene. Positive samples were retested by conventional PCR targeting the gene and sequencing. DNA was detected in eight out of ten small mammal species. Small mammal hosts from forests (14.0%) were significantly more often infected than those from grasslands (4.4%) ( < 0.001). The highest prevalence was found in the mostly forest-inhabiting genus (14.8%) and the lowest in (6.6%), which inhabits grasslands. The prevalence was higher in (46.3%) than in the complex (8.6%). Adult ticks were more often infected than nymphs ( = 0.0199). All sequenced rickettsiae in complex ticks were , and the ones in were . Unlike adults, questing nymphs have had only one blood meal, which explains the higher prevalence in adults. Interestingly, habitat type did influence infection probability in small mammals, but did not in ticks. A possible explanation may be the high prevalence in and which were more abundant in the forest.
PubMed: 37513780
DOI: 10.3390/pathogens12070933 -
Medecine Sciences : M/S Dec 2023Animal models remain important for the study of human pathologies. The most widely used model (mouse) is an endothermic mammal like humans, maintained at ambient...
Animal models remain important for the study of human pathologies. The most widely used model (mouse) is an endothermic mammal like humans, maintained at ambient temperatures (22 °C). Its energy metabolism is overactivated, a situation rarely observed in humans thanks to various adaptations (clothing, heating…). The thermoneutral zone is defined as a range of ambient temperatures that allows an organism to regulate body temperature without using additional thermoregulatory processes. There are many examples of divergent results between studies conducted at 22 °C or at 30 °C (thermoneutrality for mice). Therefore, it seems essential to take into account the housing temperature both for animal welfare and for the relevance of the results.
Topics: Humans; Animals; Mice; Models, Animal; Body Temperature Regulation; Energy Metabolism; Temperature; Mammals
PubMed: 38108724
DOI: 10.1051/medsci/2023176 -
The Veterinary Clinics of North... Sep 2023Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in... (Review)
Review
Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to exotics. Exotic animals present unique challenges with AKI management such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for exotic companion mammals. The following article will discuss the same in non-mammalian patients.
Topics: Animals; Animals, Exotic; Critical Care; Prognosis; Acute Kidney Injury; Critical Illness; Mammals
PubMed: 37302935
DOI: 10.1016/j.cvex.2023.05.005 -
Ecology and Evolution Nov 2023Water availability significantly influences bird and mammal ecology in terrestrial ecosystems. However, our understanding of the role of water as a limiting resource for...
Water availability significantly influences bird and mammal ecology in terrestrial ecosystems. However, our understanding of the role of water as a limiting resource for birds and mammals remains partial because most of the studies have focused on surface water bodies in desert and semi-desert ecosystems. This study assessed the use of two types of surface water bodies (waterholes and epikarst rock pools) and one arboreal (water-filled tree holes) by birds and mammals in the seasonally dry tropical forests of the Calakmul Biosphere Reserve in southern Mexico. We deployed camera traps in 23 waterholes, 22 rock pools, and 19 water-filled tree holes in this karstic region to record visits by small, medium, and large-bodied birds and mammals during the dry and rainy seasons. These cameras were set up for recording videos documenting when animals were making use of water for drinking, bathing, or both. We compared the species diversity and composition of bird and mammal assemblages using the different types of water bodies by calculating Hill numbers and conducting nonmetric multidimensional scaling (NMDS), indicator species, and contingency table analyses. There was a greater species richness of birds and mammals using surface water bodies than tree holes during both seasons. There were significant differences in species composition among bird assemblages using the different water bodies, but dominant species and diversity remained the same. Terrestrial and larger mammalian species preferentially used surface water bodies, whereas arboreal and scansorial small and medium mammals were more common in arboreal water bodies. These findings suggest that differences in water body characteristics might favor segregation in mammal activity. The different water bodies may act as alternative water sources for birds and complementary sources for mammals, potentially favoring species coexistence and increasing community resilience to environmental variation (e.g., fluctuations in water availability). Understanding how differences in water bodies favor species coexistence and community resilience is of great relevance from a basic ecological perspective but is also crucial for anticipating the effects that the increased demand for water by humans and climate change can have on wildlife viability.
PubMed: 38034340
DOI: 10.1002/ece3.10781 -
ELife Mar 2024Gasdermins oligomerize to form pores in the cell membrane, causing regulated lytic cell death called pyroptosis. Mammals encode five gasdermins that can trigger...
Gasdermins oligomerize to form pores in the cell membrane, causing regulated lytic cell death called pyroptosis. Mammals encode five gasdermins that can trigger pyroptosis: GSDMA, B, C, D, and E. Caspase and granzyme proteases cleave the linker regions of and activate GSDMB, C, D, and E, but no endogenous activation pathways are yet known for GSDMA. Here, we perform a comprehensive evolutionary analysis of the gasdermin family. A gene duplication of GSDMA in the common ancestor of caecilian amphibians, reptiles, and birds gave rise to GSDMA-D in mammals. Uniquely in our tree, amphibian, reptile, and bird GSDMA group in a separate clade than mammal GSDMA. Remarkably, GSDMA in numerous bird species contain caspase-1 cleavage sites like YVAD or FASD in the linker. We show that GSDMA from birds, amphibians, and reptiles are all cleaved by caspase-1. Thus, GSDMA was originally cleaved by the host-encoded protease caspase-1. In mammals the caspase-1 cleavage site in GSDMA is disrupted; instead, a new protein, GSDMD, is the target of caspase-1. Mammal caspase-1 uses exosite interactions with the GSDMD C-terminal domain to confer the specificity of this interaction, whereas we show that bird caspase-1 uses a stereotypical tetrapeptide sequence to confer specificity for bird GSDMA. Our results reveal an evolutionarily stable association between caspase-1 and the gasdermin family, albeit a shifting one. Caspase-1 repeatedly changes its target gasdermin over evolutionary time at speciation junctures, initially cleaving GSDME in fish, then GSDMA in amphibians/reptiles/birds, and finally GSDMD in mammals.
Topics: Animals; Caspase 1; Caspases; Gasdermins; Inflammasomes; Amphibians; Reptiles; Birds
PubMed: 38497531
DOI: 10.7554/eLife.92362