Izvestiia Akademii nauk. Seriia biologicheskaia最新文献

The effect of abscisic acid (ABA) and fluridone on the content of endogenous phytohormones and free polyamines and the intensity of oxidative stress was studied in plants of Mesembryanthemum crystallinum L. under salinity. It was shown that the pretreatment of plant roots with 1 μM ABA, followed by the action of 300 mM NaCl, caused a protective effect and improved the physiological state of the plants, which was manifested in increased biomass and content of available cytokinins and reduced values of the indicators of oxidative stress. It was noted that the inhibitor fluridone reduced the effect of ABA and acted as a pro-oxidant.

The cytomorphological and biochemical composition of the blood has been studied for the deep-dwelling (bottom) morphotype of the Baikal omul infected by plerocercoids of Diphyllobothrium dendriticum, during the fish spawning migration. A decrease in hemoglobin synthesis and an increase in the proliferative activity of erythroid cells have been registered. The changes in the leukocyte population composition, immunoglobulin, and total protein concentrations evidenced a disorder of blood cell proliferation and differentiation and suppression of the immune response in the infected fish. The changes in the humoral and cell factors of homeostasis in Coregonus migratorius infected by D. dendriticum during the spawning period remain within the limits of the adaptive possibilities of the species.

The spatial arrangement of muscles in the oral suckers of six trematode species belonging to five families of the order Paramphistomatida is described. The functional load and adaptive significance of different muscle groups in the suckers themselves and the associated structures--preoral lip and muscular cap--are discussed. Complete section series in three projections have been examined; this demonstrates the presence of previously unnoticed structures, namely, semicircular and diagonal muscles, regulating shape of the oral cavity, and short longitudinal muscles, acting as a sphincter, as well as localization of the largest internal muscles on the sucker lateral sides. It has been shown that the presence of internal longitudinal muscles suggests that the organs in question are closer to the oral suckers of other trematodes rather than to their pharynxes.

An interfaced analysis of change of forage vegetation, nutrition of saigas (Saiga tatarica), and their state in tne steppe regions of Russia is performed. It is noted that the percent of graminoids has increased considerably and the proportion of forbs has decreased in the vegetation of current pastures, which has had a negative impact on the nutrition and state of saigas. It is shown that the lower nutritional value of graminoids has caused a decrease in the digestibility of forage used by saigas and does not provide the physiological requirements of the animals. It is established that modern steppe pastures, where gramineous communities prevail, are of little use or absolutely unsuitable for the stable existence of saiga populations. Only separate dwelling places with an abundance of forbs continue to provide adequate nutrition for saigas and well-being for their local groupings.

In this paper, we analyzed our own results and published data on the expression of regulatory genes encoding transcription factors Pax6/PAX6, Pitx2/PITX2, Fox1/FOXC1, Prox1/PROX1, Oct4/OCT4, Nanog/NANOG, and TGFβ2 signaling protein during morphogenesis of the cornea in vertebrates. We considered the results obtained for the cornea of model animals, primarily mice, and human fetal cornea. The main possibility of establishing common mechanisms of eye development in vertebrates in health and disease is comparative studies of eye morphogenesis of humans and animal models.

The distribution patterns and coenotic confines ofthe epiphytic lichen Lobaria pulmonaria have been studied. The factors limiting the habitat of this rare lichen species in the Kologriv Forest Nature Reserve (southern taiga subzone) have been revealed. It has been shown that L. pulmonaria is attracted to forest areas, which are less affected by humans and characterized by better light conditions than other communities. It has been found that L. pulmonaria is able to colonize trees at various ontogenetic states, beginning from virginal ones.

The frequency of occurrence of the mitotypes (control region, cytochrome b gene, and DN2 gene) has been studied for groups of gray whales feeding and growing along Chukotka Peninsula, Koryak Coast, eastern Kamchatka, and Sakhalin Island. The number of the mitotypes decreased dramatically from the northern waters southwards; however, the dominant mitotypes remained the same. Both mitochondrial lineages known for this species might be found for the whales gathering in the reproductive area along the Californian Coast in accordance with the comparison of the published and original data on the haplotypes of the control region. However, it has also been argued that similar sequences of the control region might be found in different mitochondrial genomes, and the analysis of only this site of mtDNA might lead to incorrect conclusions.

We analyzed data from our studies and other author's works concerning the influence of stress stimuli on the development of neuroendocrine and immune systems. The results of our analysis suggest that "immunological stress" induced by viral or bacterial infection, an unhealthy diet, and the mother's behavior during pregnancy and lactation are significant risk factors for the developing offspring. The brain is the key target for these factors. The continuous effect of stress stimuli during critical periods of brain development induces hyperactivity and increased response of hypothalamic-pituitary-adrenal system. This can increase the risk of the development of psychoneurological, metabolic, immunological, and behavioral disorders and the suppression of reproduction in the offspring. The plasticity of physiological systems helps the developing organism to adapt to the changing environment.