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.

Effect of Long-Term Light Deprivation on α-Tocopherol Content in Rats during Ontogeny.

We studied the effect of long-term light deprivation which began at different stages of ontogeny on the content of α-tocopherol in rats during the first 3 months of postnatal development. In the offspring postnatally exposed to constant darkness, the level of α-tocopherol in the liver, kidneys, heart, skeletal muscles, and lungs was significantly decreased at the early stages of postnatal ontogeny (2 weeks and 1 month). In rats kept under constant darkness after birth, the content of α-tocopherol in the lungs was also reduced at the age of 1 month. The modulating effect of light deprivation on the level of α-tocopherol can be associated both with the impact of disturbed circadian rhythms and with increased content of melatonin in the body.

[Absence of photoperiodism and digestive enzymes in rats: the role of the age and endogenous melatonin level.]

We studied the effect of prolonged absence of a photoperiodic signal (constant lighting and constant darkness) on the changes of digestive enzymes' activity in late postnatal ontogenesis of rats. Age-related alterations are characterized as a change in activity of enzymes, as well as a redistribution of the functional activity between the amylo- and lipolytic links, the upper and lower divisions of the gastrointestinal tract. It was shown that along with age, the activity of enzymes is affected both by the absence of photoperiodism and by the level of melatonin associated with the light regime. In conditions of light deprivation the age-related changes characterizing the «aging¼ of the digestive system are observed later compared with standard illumination and especially constant illumination.

[Circadian rhythms of antioxidant enzyme's activity in young and adult rats under light deprivation conditions.]

We studied the age-related features of circadian rhythms of superoxide dismutase (SOD) and catalase activity in the liver of rats under light deprivation. In standard light conditions (LD), significant daily fluctuations in SOD activity with a maximum at 07:00 am was detected only in young animals (1,5 months) but catalase activity was observed in young (1,5 months) and in adults (7,5 months) with peak at 04:00 am. The daily dynamics of total and specific activity of SOD and catalase in the liver in young and adult rats differed depending on the period of ontogeny in which the impact of light deprivation began. When the females and offspring were moved to darkness after birth (group LD/DD), the circadian rhythms of SOD and catalase activitys were observed in young and were absent in adult rats. However, circadian rhythms of the antioxidant enzymes (AOE) activities were inherent only adult rats when light deprivation impacted on pregnant females (group DD/DD). Changes in circadian rhythms under light deprivation were characterized either by a phase shift of the enzymes activity (in the LD/DD group) or by a violation of their develpoment in ontogeny (in the DD/DD group). During aging significant decreasing of catalase activity was compensated by an increase in the amplitude of circadian rhythms of activity of this enzyme in animals of all groups. A distinctive feature of daily fluctuations in AOЕ activity in young rats in LD and LD/DD groups can be considered the presence of an ultradian rhythm in the general circadian cycle, which had a second peak with a smaller amplitude and shorter period.

[Taxonomic and ethnical dispersion of phenomenon of pineal concretions in the gerontological context.]

Pineal gland (PG), or epiphysis, is involved in the organization of biological rhythms and adaptive reactions of the organism through the hormone melatonin. It is shown that various factors can influence the morphology and functional activity of the gland. Calcified concretions (corpora arenacea, brain sand) are unique biomineral structures of the PG, the causes of the formation and possible functional significance of which remain unclear until now. Currently, concrements have been found in several species of birds, in many mammals as well as humans; they are absent in fish, amphibians and reptiles. In this review, we have collected the available literature data on the composition, mechanisms of formation, and the possible factors affecting the accumulation of concretions in the epiphysis. Despite the fact that the generally accepted point of view is the age-dependent nature of the accumulation of pineal calcium deposits, the available data on the PG mineralization lead to the conclusion that, most likely, there is a multifactorial mechanism for the formation of concrements. In addition, the nature and crystallinity of the inorganic tissue of the pineal concretions suggest that corpora arenacea is rather a regulated and physiological than pathological type of petrification. The existence of contradictory data on the connection between the formation of brain sand and the change in the functional activity of the PG during seasonal endocrine changes and in the process of aging makes the study of deposits as the necessary and requiring in-depth investigation.

[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.

Effects of Geroprotectors on Age-Related Changes in Proteolytic Digestive Enzyme Activities at Different Lighting Conditions.

We studied the effect of melatonin and epithalon on age-related changes in proteolytic digestive enzyme activity in the pancreas and gastric mucosa of rats kept under different lighting conditions. In rats kept under standard illumination, pepsin activity and the total proteolytic activity in the stomach and pancreas increased by the age of 12 months, but then decreased. Constant and natural lighting disturbed the age dynamics of proteolytic digestive enzyme activity. Administration of melatonin and epithalon to animals exposed to constant lighting restored age dynamics of pepsin activity and little affected total proteolytic activity.

[MORPHOLOGICAL FEATURES OF NEUTROPHILS AND EOSINOPHILS GRANULES IN SAPPHIRE MINKS].

It has been established that sapphire minks have abnormality of subcellular structure of blood and bone marrow neutrophils and eosinophils. The abnormality consists in forming of abnormal "giant" granules. The si- ze and the number of abnormal granules significantly change during maturation of leucocytes in bone marrow. We have found differences between abnormal granules forming in neutrophils and eosinophils that depend on the maturing stage and the cells life cycle duration as well as morphofunctional features of these granulocytes.

[Morphological peculiarities of peripheral blood lymphocytes in arctic foxes after administration of various doses of vitamins A and E].

The aim of this work was to study the effect of various doses of vitamins A and E on the morphometric parameters and surface architectonics peculiarities of peripheral blood lymphocytes in veiled Arctic foxes. Using light microscopy, it was found that in the blood of veiled Arctic foxes (n=30) most of the lymphocytes had relatively smooth surface, and only in some cells cytoplasmic protrusions were observed. Large doses of vitamins A and E that were introduced into animal diet, caused significant reduction of morphometric parameters in relatively smooth forms of lymphocytes, while vitamin A changed the microrelief of their surface.