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101.
To test the current hypotheses on the relationship between the mating system, reproductive strategy, aggression, and secretion of testosterone, a comparative study of interactions in pair encounters, the level of parental care, and the gonadal testosterone level in males was performed in six rodent species (Clethrionomys rutilus, Meriones meridianus, Microtus arvalis, Lagurus lagurus, Lasiopodomys mandarinus, and Meriones unguiculatus) with different types of spatial-and-ethological population structures (SEPSs). It is shown that this dependence is absent in species with promiscuous mating and dominance hierarchy among males (C. rutilus and M. meridianus, SEPS type II). A trade-off, or negative correlation, was found in M. arvalis—a species with weak pair bonds and male competition for receptive females (SEPS type III). In species with persistent pair bonds and structured family groups (L. mandarinus and M. unguiculatus, SEPS type IV), no inverse relationship between the secretion of testosterone and paternal behavior was found either. Moreover, in male L. mandarinus androgens appear to stimulate paternal care.  相似文献   
102.
Main problems of neuropharmacology and its important component, psychopharmacology, are discussed in the communication. Examples of new approaches in the studies of the mechanisms of the effects of psychopharmacological agents are presented; in particular, the agents affecting functions of neuropeptide systems are described. Possibilities for creation of new psychopharmacological drugs and possibilities for their use as analyzers in the study of neurophysiological functions and pathological processes in the nervous system are discussed.  相似文献   
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1. Endogenous proteolysis in human erythrocyte membranes was studied in human erythrocyte membranes incubated at 37 degrees C by monitoring changes in 2-D electrophoretic pattern of membrane polypeptides and in the spectra of maleimide-spin labeled membranes. 2. A strong effect of exogenous proteases derived from contaminating other blood elements was found, resulting in formation of specific spots on 2-D electropherograms, requiring very careful leukocyte removal in investigations of red cell membrane protein composition and proteolysis. 3. Studies of the effects of protease inhibitors and Ca2+ confirmed a complex pattern of endogenous red cell membrane proteolysis ("self-digestion") involving many substrates and enzymes. 4. A promoting effect of high concentrations (150 mM) of Ca2+ on endogenous red cell membrane proteolysis was found.  相似文献   
105.
It has been demonstrated by the method of competitive displacement of own chromatin histone by excess total histone that chromatin dispersity influence the strength of histone-DNA interactions in a medium of physiological ionic strength. Histone NI was removed from chromatin after the quantity of total histone added to chromatin was equivalent to that existing in chromatin. The proportion of histones H2A and H2B removed from chromatin was increased after mechanical of ultrasonic degradation of chromatin at 5-20-fold excess of total extra-histone. In some histone preparations, the removal of histones H2A and H2B was not detectable at even 200-fold excess of total histone. This may be explained by strengthening histone-DNA interactions in superhelical loops of chromatin.  相似文献   
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The interactions of sexual partners and care of the offspring in male and female Mongolian gerbils reared in biparental and uniparental family groups (without an adult male) were compared. In individuals reared in biparental family groups, sexual differences related to the manifestation of parental care were small and statistically insignificant. In individuals reared in uniparental groups, the interactions of sexual partners related to grooming changed; the duration in males decreased threefold, as compared to the norm; indices of parental behavior of females and, especially of males, related to tactile stimulation of pups (huddling with pups in the nest and duration of licking pups) also decreased. The importance of the parental contribution of males, especially of tactile stimulation, in the evolution of the family-group mode of life is discussed.  相似文献   
109.

Background  

Oxidative stress induced by the production of reactive oxygen species may play a critical role in the stimulation of HIV replication and the development of immunodeficiency. This study was conducted as there are limited and inconclusive studies on the significance of a novel early marker of oxidative stress which can reflect the total antioxidant capacity in HIV patients,  相似文献   
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