Higher masseter muscle mass in grazing than in browsing ruminants

Using cranioskeletal measurements, several studies have generated evidence that grazing ruminants have a more pronounced mastication apparatus, in terms of muscle insertion areas and protuberances, than browsing ruminants, with the resulting hypothesis that grazers should have larger, heavier chewing muscles than browsers. However, the only investigation of this so far [Axmacher and Hofmann (J Zool 215:463-473, 1988)] did not find differences between ruminant feeding types in the masseter muscle mass of 22 species. Here, we expand the dataset to 48 ruminant species. Regardless of phylogenetic control in the statistical treatment, there was a significant positive correlation of body mass and masseter mass, and also a significant association between percent grass in the natural diet and masseter mass. The results support the concept that ruminant species that ingest more grass have relatively larger masseter muscles, possibly indicating an increased requirement to overcome the resistance of grass forage. The comparative chewing resistance of different forage classes may represent a rewarding field of ecophysiological researc

Immune response of hibernating European bats to a fungal challenge

Immunological responses of hibernating mammals are suppressed at low body temperatures, a possible explanation for the devastating effect of the white-nose syndrome on hibernating North American bats. However, European bats seem to cope well with the fungal causative agent of the disease. To better understand the immune response of hibernating bats, especially against fungal pathogens, we challenged European greater mouse-eared bats (Myotis myotis) by inoculating the fungal antigen zymosan. We monitored torpor patterns, immune gene expressions, different aspects of the acute phase response and plasma oxidative status markers, and compared them with sham-injected control animals at 30 min, 48 h and 96 h after inoculation. Torpor patterns, body temperatures, body masses, white blood cell counts, expression of immune genes, reactive oxygen metabolites and non-enzymatic antioxidant capacity did not differ between groups during the experiment. However, zymosan injected bats had significantly higher levels of haptoglobin than the control animals. Our results indicate that hibernating greater mouse-eared bats mount an inflammatory response to a fungal challenge, with only mild to negligible consequences for the energy budget of hibernation. Our study gives a first hint that hibernating European bats may have evolved a hibernation-adjusted immune response in order to balance the trade-off between competent pathogen elimination and a prudent energy-saving regime

Population genetics of the main population of brown bears in southwest Asia

Genetic studies of the Eurasian brown bear (Ursus arctos) have so far focused on populations from Europe and North America, although the largest distribution area of brown bears is in Asia. In this study, we reveal population genetic parameters for the brown bear population inhabiting the Grand Kaçkar Mountains (GKM) in the north east of Turkey, western Lesser Caucasus. Using both hair (N = 147) and tissue samples (N = 7) collected between 2008 and 2014, we found substantial levels of genetic variation (10 microsatellite loci). Bear samples (hair) taken from rubbing trees worked better for genotyping than those from power poles, regardless of the year collected. Genotyping also revealed that bears moved between habitat patches, despite ongoing massive habitat alterations and the creation of large water reservoirs. This population has the potential to serve as a genetic reserve for future reintroductions in the Middle East. Due to the importance of the GKM population for on-going and future conservation actions, the impacts of habitat alterations in the region ought to be minimized; e.g., by establishing green bridges or corridors over reservoirs and major roads to maintain habitat connectivity and gene flow among populations in the Lesser Caucasus

Epigenetic signatures of social status in wild female spotted hyenas (Crocuta crocuta)

In mammalian societies, dominance hierarchies translate into inequalities in health, reproductive performance and survival. DNA methylation is thought to mediate the effects of social status on gene expression and phenotypic outcomes, yet a study of social status-specific DNA methylation profiles in different age classes in a wild social mammal is missing. We tested for social status signatures in DNA methylation profiles in wild female spotted hyenas (Crocuta crocuta), cubs and adults, using non-invasively collected gut epithelium samples. In spotted hyena clans, female social status influences access to resources, foraging behavior, health, reproductive performance and survival. We identified 149 differentially methylated regions between 42 high- and low-ranking female spotted hyenas (cubs and adults). Differentially methylated genes were associated with energy conversion, immune function, glutamate receptor signalling and ion transport. Our results provide evidence that socio-environmental inequalities are reflected at the molecular level in cubs and adults in a wild social mammal

Assessing Coagulation Parameters in Healthy Asian Elephants (Elephas maximus) from European and Thai Populations

The Asian elephant population is continuously declining due to several extrinsic reasons in their range countries, but also due to diseases in captive populations worldwide. One of these diseases, the elephant endotheliotropic herpesvirus (EEHV) hemorrhagic disease, is very impactful because it particularly affects Asian elephant calves. It is commonly fatal and presents as an acute and generalized hemorrhagic syndrome. Therefore, having reference values of coagulation parameters, and obtaining such values for diseased animals in a very short time, is of great importance. We analyzed prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen concentrations using a portable and fast point-of-care analyzer (VetScan Pro) in 127 Asian elephants from Thai camps and European captive herds. We found significantly different PT and aPTT coagulation times between elephants from the two regions, as well as clear differences in fibrinogen concentration. Nevertheless, these alterations were not expected to have biological or clinical implications. We have also sequenced the coagulation factor VII gene of 141 animals to assess the presence of a previously reported hereditary coagulation disorder in Asian elephants and to investigate the presence of other mutations. We did not find the previously reported mutation in our study population. Instead, we discovered the presence of several new single nucleotide polymorphisms, two of them being considered as deleterious by effect prediction software

Intravital Dynamic and Correlative Imaging of Mouse Livers Reveals Diffusion-Dominated Canalicular and Flow-Augmented Ductular Bile Flux

Background and Aims Small‐molecule flux in tissue microdomains is essential for organ function, but knowledge of this process is scant due to the lack of suitable methods. We developed two independent techniques that allow the quantification of advection (flow) and diffusion in individual bile canaliculi and in interlobular bile ducts of intact livers in living mice, namely fluorescence loss after photoactivation and intravital arbitrary region image correlation spectroscopy. Approach and Results The results challenge the prevailing “mechano‐osmotic” theory of canalicular bile flow. After active transport across hepatocyte membranes, bile acids are transported in the canaliculi primarily by diffusion. Only in the interlobular ducts is diffusion augmented by regulatable advection. Photoactivation of fluorescein bis‐(5‐carboxymethoxy‐2‐nitrobenzyl)‐ether in entire lobules demonstrated the establishment of diffusive gradients in the bile canalicular network and the sink function of interlobular ducts. In contrast to the bile canalicular network, vectorial transport was detected and quantified in the mesh of interlobular bile ducts. Conclusions The liver consists of a diffusion‐dominated canalicular domain, where hepatocytes secrete small molecules and generate a concentration gradient and a flow‐augmented ductular domain, where regulated water influx creates unidirectional advection that augments the diffusive flux

Mitogenome Phylogeny Including Data from Additional Subspecies Provides New Insights into the Historical Biogeography of the Eurasian lynx Lynx lynx.

Previous molecular studies of the wide-ranging Eurasian lynx Lynx lynx focused mainly on its northern Palearctic populations, with the consequence that the reconstruction of this species' evolutionary history did not include genetic variation present in its southern Palearctic distribution. We sampled a previously not considered Asian subspecies (L. l. dinniki), added published data from another Asian subspecies (L. l. isabellinus), and reassessed the Eurasian lynx mtDNA phylogeny along with previously published data from northern Palearctic populations. Our mitogenome-based analyses revealed the existence of three major clades (A: Central Asia, B: SE Europe/SW Asia, C: Europe and Northern Asia) and at least five lineages, with diversification in Lynx lynx commencing at least 28kyr earlier than hitherto estimated. The subspecies L. l. isabellinus harbors the most basal matriline, consistent with the origin of Lynx lynx in this subspecies' current range. L. l. dinniki harbors the second most basal matriline, which is related to, and may be the source of, the mtDNA diversity of the critically endangered Balkan lynx L. l. balcanicus. Our results suggest that the Anatolian peninsula was a glacial refugium for Eurasian lynx, with previously unconsidered implications for the colonization of Europe by this species

Planning tiger recovery: Understanding intraspecific variation for effective conservation

Although significantly more money is spent on the conservation of tigers than on any other threatened species, today only 3200 to 3600 tigers roam the forests of Asia, occupying only 7% of their historical range. Despite the global significance of and interest in tiger conservation, global approaches to plan tiger recovery are partly impeded by the lack of a consensus on the number of tiger subspecies or management units, because a comprehensive analysis of tiger variation is lacking. We analyzed variation among all nine putative tiger subspecies, using extensive data sets of several traits [morphological (craniodental and pelage), ecological, molecular]. Our analyses revealed little variation and large overlaps in each trait among putative subspecies, and molecular data showed extremely low diversity because of a severe Late Pleistocene population decline. Our results support recognition of only two subspecies: the Sunda tiger, Panthera tigris sondaica, and the continental tiger, Panthera tigris tigris, which consists of two (northern and southern) management units. Conservation management programs, such as captive breeding, reintroduction initiatives, or trans-boundary projects, rely on a durable, consistent characterization of subspecies as taxonomic units, defined by robust multiple lines of scientific evidence rather than single traits or ad hoc descriptions of one or few specimens. Our multiple-trait data set supports a fundamental rethinking of the conventional tiger taxonomy paradigm, which will have profound implications for the management of in situ and ex situ tiger populations and boost conservation efforts by facilitating a pragmatic approach to tiger conservation management worldwid

Environmental change-dependent inherited epigenetic response

Epigenetic modifications are a mechanism conveying environmental information to subsequent generations via parental germ lines. Research on epigenetic responses to environmental changes in wild mammals has been widely neglected, as well as studies that compare responses to changes in different environmental factors. Here, we focused on the transmission of DNA methylation changes to naive male offspring after paternal exposure to either diet (~40% less protein) or temperature increase (10 °C increased temperature). Because both experiments focused on the liver as the main metabolic and thermoregulation organ, we were able to decipher if epigenetic changes differed in response to different environmental changes. Reduced representation bisulfite sequencing (RRBS) revealed differentially methylated regions (DMRs) in annotated genomic regions in sons sired before (control) and after the fathers’ treatments. We detected both a highly specific epigenetic response dependent on the environmental factor that had changed that was reflected in genes involved in specific metabolic pathways, and a more general response to changes in outer stimuli reflected by epigenetic modifications in a small subset of genes shared between both responses. Our results indicated that fathers prepared their offspring for specific environmental changes by paternally inherited epigenetic modifications, suggesting a strong paternal contribution to adaptive processes

Tissue-specific epigenetic inheritance after paternal heat exposure in male wild guinea pigs

External temperature change has been shown to modify epigenetic patterns, such as DNA methylation, which regulates gene expression. DNA methylation is heritable, and as such provides a mechanism to convey environmental information to subsequent generations. Studies on epigenetic response to temperature increase are still scarce in wild mammals, even more so studies that compare tissue-specific epigenetic responses. Here, we aim to address differential epigenetic responses on a gene and gene pathway level in two organs, liver and testis. We chose these organs, because the liver is the main metabolic and thermoregulation organ, and epigenetic modifications in testis are potentially transmitted to the F2 generation. We focused on the transmission of DNA methylation changes to naive male offspring after paternal exposure to an ambient temperature increase of 10 °C, and investigated differential methylated regions of sons sired before and after the paternal exposure using Reduced Representation Bisulfite Sequencing. We detected both a highly tissue-specific epigenetic response, reflected in genes involved in organ-specific metabolic pathways, and a more general regulation of single genes epigenetically modified in both organs. We conclude that genomes are context-specifically differentially epigenetically regulated in response to temperature increase. These findings emphasize the epigenetic relevance in cell differentiation, which is essential for the specific function(s) of complex organs, and is represented in a diverse molecular regulation of genes and gene pathways. The results also emphasize the paternal contribution to adaptive processes