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Salmov N.N.,Russian Academy of Sciences | Vikhlyantsev I.M.,Russian Academy of Sciences | Ulanova A.D.,Russian Academy of Sciences | Gritsyna Y.V.,Russian Academy of Sciences | And 5 more authors.
Biochemistry (Moscow) | Year: 2015

Seasonal changes in the isoform composition of thick and thin filament proteins (titin, myosin heavy chains (MyHCs), nebulin), as well as in the phosphorylation level of titin in striated muscles of brown bear (Ursus arctos) and hibernating Himalayan black bear (Ursus thibetanus ussuricus) were studied. We found that the changes that lead to skeletal muscle atrophy in bears during hibernation are not accompanied by a decrease in the content of nebulin and intact titin-1 (T1) isoforms. However, a decrease (2.1-3.4-fold) in the content of T2 fragments of titin was observed in bear skeletal muscles (m. gastrocnemius, m. longissimus dorsi, m. biceps) during hibernation. The content of the stiffer N2B titin isoform was observed to increase relative to the content of its more compliant N2BA isoform in the left ventricles of hibernating bears. At the same time, in spite of the absence of decrease in the total content of T1 in the myocardium of hibernating brown bear, the content of T2 fragments decreased.

Saveljev A.P.,Zhitkov Russian Research Institute Of Game Management And For Farming | Shar S.,National University of Mongolia | Scopin A.E.,Zhitkov Russian Research Institute Of Game Management And For Farming | Otgonbaatar M.,Hovd State University | And 3 more authors.
Russian Journal of Biological Invasions | Year: 2015

The modern status and population trends of three alien semiaquatic mammals in a transboundary (Mongolia/Russia) ecosystem of the Uvs Nuur Hollow were studied. The muskrat, American mink, and Eurasian beaver (Sino-Mongolian subspecies) have almost equivalent size of “life arenas,” but different population trends, different success in naturalization, and different impact on native ecosystems. It is concluded that differences of naturalization in these three mammals are defined not by postintroduction history or the effect of some abiotic factors, but by the diversity and abundance of trophic niches in the Uvs Nuur Basin. It is stated that, in the conditions of a sharply continental climate and a rigid hydroregime, the adaptation to a new ecosystem is easier for herbivorous mammals having richer and stabler food resources than for carnivorous animals. The behavioral adaptive mechanisms promoting naturalization are described. The evolutionary stability of the building instinct is very important for beaver colonization of new habitats. The utilitarian value of alien species for the human population of the given territory is estimated. © 2015, Pleiades Publishing, Ltd.

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