Signals of positive selection in genomes of palearctic Myotis-bats coexisting with a fungal pathogen.

Disease can act as a driving force in shaping genetic makeup across populations, even species, if the impacts influence a particularly sensitive part of their life cycles. White-nose disease is caused by a fungal pathogen infecting bats during hibernation. The mycosis has caused massive population declines of susceptible species in North America, particularly in the genus Myotis. However, Myotis bats appear to tolerate infection in Eurasia, where the fungal pathogen has co-evolved with its bat hosts for an extended period of time. Therefore, with susceptible and tolerant populations, the fungal disease provides a unique opportunity to tease apart factors contributing to tolerance at a genomic level to and gain an understanding of the evolution of non-harmful in host-parasite interactions. To investigate if the fungal disease has caused adaptation on a genomic level in Eurasian bat species, we adopted both whole-genome sequencing approaches and a literature search to compile a set of 300 genes from which to investigate signals of positive selection in genomes of 11 Eurasian bats at the codon-level. Our results indicate significant positive selection in 38 genes, many of which have a marked role in responses to infection. Our findings suggest that white-nose syndrome may have applied a significant selective pressure on Eurasian Myotis-bats in the past, which can contribute their survival in co-existence with the pathogen. Our findings provide an insight on the selective pressure pathogens afflict on their hosts using methodology that can be adapted to other host-pathogen study systems.

[SPECIFICITY OF CONTENT AND MORPHOLOGY OF PERIPHERAL BLOOD CELLS IN THREE BAT SPECIES OF KARELIA DURING HIBERNATION].

Pronounced leukopenia during hibernation was found in bats (Chiroptera) of Karelia - brown long-eared bat (Plecotus auritus), Brandt's bat (Myotis brandtii) and northern bat (Eptesicus nilssoni). A higher content of lymphocytes, eosinophils and basophils was revealed in the northern bat featuring an increased resistance to cold as compared to the Brandt's bat and the brown long-eared bat. The differences in ratio of particular lymphocyte types may be related to biological, ecological and physiological peculiarities of the species studied.

[Tocopherol content in tissues of mammals of different ecogenesis].

Concentration of vitamin E (alpha-tocopherol) was studied in liver, kidney, heart, and skeletal muscle of 12 mammalian species. 9 of them inhabiting under natural conditions, while 3 being farm-bred. In most of the species the highest tocopherol distribution and level have been revealed, including those in taxonomically close species. These differences seem to be due to ecological peculiarities of the animals. The obtained results allow considering as one of factors of maintenance of the natural antioxidant system at the steady level.