As Extracellular Glutamine Levels Decline,Asparagine Becomes an Essential Amino Acid

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Perpendicular axes of differentiation generated by mitochondrial introgression

Differential introgression of mitochondrial vs. nuclear DNA generates discordant patterns of geographic variation and can promote population divergence and speciation. We examined a potential case of mitochondrial introgression leading to two perpendicular axes of differentiation. The Eastern Yellow Robin Eopsaltria australis, a widespread Australian bird, shows a deep mitochondrial split that is perpendicular to north–south nuclear DNA and plumage colour differentiation. We propose a scenario to explain this pattern: (i) first, both nuclear and mitochondrial genomes differentiated in concert during north–south population divergence; (ii) later, their histories disconnected after two mitochondrial introgression events resulting in a deep mitochondrial split perpendicular to the nuclear DNA structure. We explored this scenario by coalescent modelling of ten mitochondrial genes and 400 nuclear DNA loci. Initial mitochondrial and nuclear genome divergences were estimated to have occurred in the early Pleistocene, consistent with the proposed scenario. Subsequent climatic transitions may have driven later mitochondrial introgression. We consider neutral introgression unlikely and instead propose that the evidence is more consistent with adaptive mitochondrial introgression and selection against incompatible mitochondrial‐nuclear combinations. This likely generated an axis of coastal‐inland mitochondrial differentiation in the face of nuclear gene flow, perpendicular to the initial north–south axis of differentiation (reflected in genomewide nuclear DNA and colour variation).     

A novel framework for evaluating in situ breeding management strategies in endangered populations

Conservation breeding management aims to reduce inbreeding and maximize the retention of genetic diversity in endangered populations. However, breeding management of wild populations is still rare, and there is a need for approaches that provide data-driven evidence of the likelihood of success of alternative in situ strategies. Here, we provide an analytical framework that uses in silico simulations to evaluate, for real wild populations, (i) the degree of population-level inbreeding avoidance, (ii) the genetic quality of mating pairs, and (iii) the potential genetic benefits of implementing two breeding management strategies. The proposed strategies aim to improve the genetic quality of breeding pairs by splitting detrimental pairs and allowing the members to re-pair in different ways. We apply the framework to the wild population of the Critically Endangered helmeted honeyeater by combining genomic data and field observations to estimate the inbreeding (i.e., pair-kinship) and genetic quality (i.e., Mate Suitability Index) of all mating pairs for seven consecutive breeding seasons. We found no evidence of population-level inbreeding avoidance and that ~91.6% of breeding pairs were detrimental to the genetic health of the population. Furthermore, the framework revealed that neither proposed management strategy would significantly improve the genetic quality or reduce inbreeding of the mating pairs in this population. Our results demonstrate the usefulness of our analytical framework for testing the efficacy of different in situ breeding management strategies and for making evidence-based management decisions.     

Salmonella typhimurium population in water environment under the influence of temperature

The strategy of the adaptation of S. typhimurium population to water environment under the influence of temperature factor was studied by scanning electron microscopy. Salmonellae were found to adhere to the surface of the Daphnia chitin covering. The study revealed that S. typhimurium population existed in water in the form of covered microcolonies as well as in the form of spheroplast-type cells and small cells in the L-form, joined with bands. The viability of salmonellae in water environment was studied without interaction and following interaction with Daphnia.     

Activity of propriospinal neurons in segments C3 and C4 during fictitious locomotion in cats

Activity of propriospinal neurons in segments C3 and C4 was recorded in immobilized decerebrate cats, whose spinal cord was divided at the lower thoracic level, during locomotor activity of neuronal mechanisms controlling the forelimbs (fictitious locomotion of the forelimbs). Neurons were identified according to antidromic responses to stimulation of the lateral column of the spinal cord at level C6. Antidromic responses also appeared in 70% of these neurons to stimulation of the medullary lateral reticular nucleus. During fictitious locomotion, i.e., in the absence of afferent signals from the limb receptors, rhythmic modulation of the discharge of most neurons was observed, correlating with activity of motoneurons. If the rostral region of the cervical enlargement of the spinal cord was cooled, causing generation of the locomotor rhythm to cease, rhythmic activity of propriospinal neurons in segments C3 and C4 also ceased. The main source of modulation of activity of propriospinal neurons in segments C3 and C4 is thus the central spinal mechanisms controlling activity of the forelimbs.Institute for Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. M. V. Lomonosov Moscow University. Translated from Neirofiziologiya, Vol. 17, No. 3, pp. 320–326, May–June, 1985.     

Work with youth--the basis of educational programs aimed at the prevention of HIV infection

During the recent 10 years, 1987-1997, syphilis morbidity was found to increase 60-fold in Omsk Province. In 1997 adolescents constituted 6.0% in the structure of persons who contacted the disease. In this year more than 500 adolescent using drugs were registered in the region. The introduction of drugs by injection was practiced by 9.6% of the adolescents. The program aimed mainly at changing the behavior of young people with orientation on the choice of a healthy mode of life and theirs information about risk factors associated with sex transmitted diseases particularly HIV infection is discussed.     

A cultured concentrated inactivated vaccine against tick-borne encephalitis studied during the immunization of children and adolescents

The word deals with the results obtained in the study of the reactogenicity and immunological activity of concentrated and inactivated tissue-culture tick-borne encephalitis vaccine, manufactured by the Chumakov Institute of Poliomyelitis and Viral Encephalitides, in the immunization of children and adolescents. The vaccine proved to be moderately reactogenic and exhibited pronounced immunological activity. In 91.5% of the immunized children the fourfold increase of the antibody level was observed. On the basis of the data obtained in this study the tick-borne encephalitis vaccine was recommended for use in medical practice for the prophylaxis of tick-borne encephalitis among children and adolescents.