[Analysis of various taxon specific parameters of the guard hair cuticles for development of the mammalian identification system by morphometric characteristics of their hair]. / Analiz nekotorykh takson-spetsifichnykh parametrov kutikuly ostevykh volos dlia razrabotki sistemy identifikatsii mlekopitaiushchikh po morfometricheskim kharakteristikam volosa.

Mathematical indices of the structure of the external surface of guard hairs have been developed on the basis of a KS300 system of automatic image analysis (Kontrom Elektronik, Germany), which are capable of serving, in some cases, as diagnostic parameters of large taxa (order, family). The guard hair morphology is affected by various factors, such as body region where a given hair is located, season, diet, sex of individual, and state of its health, which is expressed in changes of some morphometric data. For a more complete analysis of the characteristics of the guard hair structure, it is necessary to use indices that describe the macro- and microstructure of the external surface of the stem and its internal structure.

[The attraction of Campbell (Phodopus campbelli) and Djungarian (Phodopus sungorus) hamster pups to the odor of the secretion from specific complexes in the corners of the mouth of the mother]. / Privlechenie detenyshei khomiachka Kémpbella (Phodopus campbelli) i dzhungarskogo (Phodopus sungorus) zapakhom sekreta spetsificheskikh kompleksov v uglakh rta samki-materi.

The hamsters, Phodopus campbelli and Ph. sungorus have additional sacculi at the opening of the cheek pouches. The secretion of additional sacculi is very important for normalization of some aspects of the hamsters' physiology, as well as growth and development of pups, and also for chemical communication. We studied the role of the mother's additional sacculi secretion in mother-youngs interaction. It was shown that this secretion is most attractive for pups of both species from 6th to 11th day after the birth. During this period the pups begin to consume solid food but their own complexes only begin to form. Hence, pups may use the mother's additional sacculi as an additional (and may be the main) source of the secretion at this time. The difference in behavioral patterns of pups of the two studied species suggests some specific features of postnatal ontogenesis of additional sacculi.

[Study of diversity of the animal population in zonal climatic gradients using the transect method]. / Izuchenie raznoobraziia zhivotnogo naseleniia v zonal'nykh klimaticheskikh gradientakh s ispol'zovaniem transektnogo metoda.

Zonal trends of changes in animal population diversity on land are studied with the models of individual taxa and multispecies communities. Development of the transect method and use of different scale topoecological gradients make it possible to follow the succession of the species composition and topical preferences of individual species, as well as changes in their absolute and relative abundance, which lead to changes in the structure and pattern of functioning of the community as a whole. Modern methodological approaches concerning organization of complex studies on megatransects crossing several natural zones are analyzed. Methods of estimation of inter- and intrazonal changes in the animal population structure and diversity are discussed.

[Response of adult djungarian hamsters (Phodopus sungorus) to odor signals of species of their own and opposite sex during different seasons with the reference to reproduction process]. / Otvet vzroslykh dzhungarskikh khomiachkov (Phodopus sungorus) na zapakhovye signaly osobei svoego i protivopoloznogo pola v raznye sezony goda v sviazi s protekaniem protsessa razmnozheniia.

Studies were carried out on adult Djungarian hamster (Phodopus sungorus) males living in familial pairs under natural thermal and light regimes year-round. The response of hamsters to the odors of urine, secretory substances of the midabdominal gland and additional saccules in the ostium of cheek pouches, and faeces from conspecific males and females were studied. The results obtained suggest that the odors of urine and also feces play an important role in sexual recognition of individuals. These odors are especially attractive for the males in summer, during the period of active breeding. The tested males examined the odor of the midabdominal gland from individuals of the same sex reliably longer throughout the year, but in winter the interest in this odor was higher than in summer. These secretory substances appear to be important in organization of territorial interactions between individuals. The results of observations on breeding and the data on sex ratio in the broods from pairs with the tested males were compared to similar data obtained earlier for Roborovskii hamsters (Sokolov and Feoktistova, 1996). Similarities and differences were found in the course of breeding in the studied species.

Towards defining the pathogenesis of the hairless phenotype.

Mutation of the hairless (hr) gene in mice causes severe abnormalities during the first hair follicle regression (catagen), resulting in complete baldness. Here, we further characterize how hairlessness develops in HRS/J hairless mouse skin (hr) by histology, histochemistry, immunohistology, and in situ hybridization. We show that, in hr skin, only two defined epithelial cell populations in the distal outer root sheath (ORS) retain their integrity, whereas the rest of the ORS disintegrates. The surviving distal ORS forms the characteristic utriculi, whereas the remnants of the bulge get isolated from other epithelial compartments, but retain the capacity to proliferate and to produce either columnar epithelial outgrowths or selected dermal cysts. Normal dermal papilla structures get lost during the development of hairlessness. Based on the patterns of keratin 17 mRNA and neural cell adhesion molecule antigen expression, and on the distribution of alkaline phosphatase activity, we propose that dermal cysts in hr skin arise from (i) the central ORS, (ii) bulge-derived cells, or (iii) the disintegrating proximal ORS under the influence of dermal papilla remnants. The hr mutation seems to disrupt the integrity of key functional tissue units in the hair follicle, possibly due to a dysregulation of normal, catagen-associated apoptosis and/or an impairment of cell adhesion, whereas the distal follicle epithelium (including its stem cell region) seems to be largely protected from this. Thus, hairless mice offer a unique model for dissecting the as yet obscure functional properties of the hr gene product in maintaining follicle integrity during normal catagen.

[Taxonomy of the musk deer (Artiodactyla, Mammalia)]. / Sistematika kabargi (Artiodactyla, Mammalia).

We studied the chromosome sets and specific morphological features and phenetic traits of hair cover coloration, as well the pattern of its inheritance upon experimental hybridization. The diploid set of chromosomes in the animals from the northern part of the range contains 2n = 58 (there are two additional B-chromosomes in the Far Eastern musk deer) and is identical to that from the southern musk deer forms. Discrete polymorphic features of neck and hair cover coloration have been identified in the northern and southern musk deer, and these are used as taxonomic features. A map illustrates distribution of the established subspecies.

[The histostructure of the adrenal gland in the Campbell hamster after extirpation of a specific midventral gland]. / Izuchenie gistostruktury nadpochechnika khomiachka Kémpbella pri ékstirpatsii spetsificheskoi srednebriushnoi zhelezy.

We studied the histological structure of the adrenal glands within four months after extirpation of the midabdominal gland in newborn hamsters. Structural changes of the cells in all zones of the adrenal cortex suggest development of a compensatory reaction to the midabdominal gland extirpation. Hence, the midabdominal gland was a component of the complex of endocrine glands and synthesizes, in all likelihood, some precursors of steroid hormones and, thus, fulfilled both the exocrine and endocrine functions.