Secretion of organic acids and bases by the kidneys of marine teleosts

In the experiments performed on kidneys of 5 species of marine Teleostei, morphological peculiarities in secretion of 8 fluorescent organic acids (uranin, primulin, tripaphlavin, erythrosin etc.) and in 5 organic bases (rhodamin C, auramin etc.) have been studied. At a very low concentration in the incubation medium--about 0.005 mg/ml--the substances mentioned penetrate into the epithelial cell of the canaliculus; its weak fluorescence appears, and soon they begin to be excreted in great amount through the apical part of the plasmolemma and accumulated in the canalicular lumen. All the substances studied accumulate in the cell and only some of them (uranin, primulin, titanic yellow, etc.) are secreted into the canalicular lumen. Penicillinum and probenecide inhibit penetration of the organic acids into the cell through the basal membrane. Uranin secretion into the canalicular lumen is inhibited in the presence of furocemid; amilorid, magnium and sulfate ions do not influence secretion of the organic acids. Secretion of the organic bases does not change when paraaminohippuric acid and furocemid are added to the medium, but it decreases when concentration of magnium ions increases.     

Cross microbial antigens of the human bronchopulmonary apparatus]

The work was undertaken to assess the antigenic affinity of some Neisseria perflava, Klebsiella pneumoniae, Staphylococcus aureus strains serving as active sensitinogen of the human broncho-pulmonary apparatus. With the aid of the complement fixation test, precipitation after Ouchterolony, and immunoelectrophoresis there was established the presence of a series of similar antigenic determinants common for all the three microbes and for determinant responsible for the cross reactions of two microbes only.     

Etiologic role of bacteria of the genus Providencia in acute intestinal diseases

A study was made of morphological, cultural, biochemical properties and antigenic structure (by O-antigen) of 59 strains isolated in group acute intestinal affection of children at the pioneer camp. By the combination of biochemical properties (31 tests) all the cultures isolated were referred to Providencia alcalifaciens of biotype 7. Serological typing with the aid of experimental diagnostic agglutinating O-sera showed these strains to be referred to serological group O2. Identity of the O-antigen of the isolated cultures to the standard O2 strain was confirmed by the results of cross reactions of agglutinin absorption. The results of bacteriological and clinico-epidemiological studies offered a possibility of regarding the isolated Providencia alcalifaciens of serological group O2 as the causative agents of the group intestinal disease in children.     

pH-induced conformational changes of DNA

The electrophoretic mobility of calf thymus DNA has been measured in aqueous buffered solutions as a function of pH. In the pH range 3.7–3.0, two electrophoretic species appear. The faster one migrates with the mobility of native DNA, the slower one migrates with a mobility close to that of thermally denatured DNA. The ratio of the two species varies with pH. Decreasing the pH increase the relative amount of the slower-moving component. These results may be interpreted by assuming that the DNA used in these experiments has a broad heterogeneity of base composition and that the conformational stability with respect to pH increases with increasing G + C content.