Toward a population genetic analysis of Salmonella: genetic diversity and relationships among strains of serotypes S. choleraesuis, S. derby, S. dublin, S. enteritidis, S. heidelberg, S. infantis, S. newport, and S. typhimurium.

Variation in the chromosomal genomes of 1527 isolates of eight common serotypes (O and H antigen profiles) of Salmonella was assessed by analysis of electrophoretically demonstrable allelic polymorphism at 23 metabolic enzyme loci. Seventy-one distinctive electrophoretic types, representing multilocus genotypes, were identified. A basically clonal population structure was indicated by the presence of strong linkage disequilibrium among enzyme loci, the association of each serotype with a relatively small number of multilocus enzyme genotypes, and the global distribution of certain genotypes. For each of six of the serotypes, 83-96% of isolates were members of a single clone. The occurrence of each of four serotypes (S. derby, S. enteritidis, S. infantis, and S. newport) in isolates of clones belonging to several evolutionary lineages, some of which are distantly related, suggests that the horizontal transfer and recombination of chromosomal genes mediating expression of cell-surface antigens has been a significant process in the evolution of the salmonellae. Two divergent clone clusters of S. derby differ in the relative frequency with which they cause disease in birds versus mammals, and two major lineages of S. newport differ in the frequency with which their clones are associated with disease in humans versus animals.     

Rheumatic diseases in the U.S.S.R

Despite our inability to precisely prognosticate disease, accumulation of knowledge about risk factors allows us to form a real basis for attempts at primary prevention of rheumatic disease. Because rheumatic diseases are multifactorial in nature, it may be suggested that the more factors an individual has the higher is the risk of disease. Relative risk values are certain to have a known limitation, since they are not independent. In addition, the number of risk factors may be significantly more than that known today. Increasing our knowledge in disease etiology and pathogenesis will definitely increase the number of risk factors. At the same time, available data may serve as a basis for developing a system for individual and group prognosis, the latter being to a certain degree tentative for the majority of diseases. All factors affecting disease development and course are divided into the controllable and the uncontrollable. The majority of the factors mentioned--especially, the environmental--are controllable ones. So the challenge facing practitioners and scientists involves development of a comprehensive system of recommendations aimed at elimination or maximum lessening of unfavorable risk factors, which is the only real basis for primary rheumatic disease prophylaxis.     

基于16S rRNA 初步探讨福建华溪蟹与修水华溪蟹的遗传分化

采用PCR结合DNA测序技术,测定两种华溪蟹Sinopotamon.fukienense 与 S.xiusuiense 线粒体16S rRNA基因序列的组成和变异。经比对获得513 bp的核苷酸序列,并分析S.fukienense与S.xiusuiense 间的的遗传分化。结果显示S.fukienense和S.xiusuiense两个群体之间的遗传距离为0.032±0.006,遗传分化指数（Fst）为0.70336,基因流(Nm)为0.11。这表明两群体间高度分化,基因交流很少。重建的系统发生显示它们各自形成独立的分支,这与形态学鉴定结果基本一致。     

New approach in treatment of cardiac decompensation in U. S. S. R.

Based on Meerson's fundamental work^3,4 on the genesis of ventricular hypertrophy and decompensation, Russian investigators supplemented the conventional therapy of cardiac decompensation with preparations related to the synthesis of protein and nucleic acids. The merit of the supplemental treatment was shown in the clinical course as well as in various objective criteria (blood chemistry, hemodynamics, systolic parameters, ECG). The reported results are highly significant and their method merits trial in other centers.