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A simplified procedure for filter paper electrophoresis is described in which disturbing factors such as evaporation, heating, buffer concentration gradients, and pH changes in the electrode vessels were reduced to a minimum. Artificial mixtures of highly purified proteins could be separated and the components isolated. The application of the method to a variety of studies on serum proteins is demonstrated. Protein concentration in paper segments was determined by two different methods of protein estimation. Curves were obtained showing the same five major peaks for normal serum as found by the classical methods of free electrophoresis. Comparisons were made of the areas of the various components under the curves obtained with the different methods. Two dimensional electrophoresis was applied to serum and serum components. It proved of value in demonstrating the heterogeneity of fractions such as the γ-globulin of serum. The polysaccharide dextran was used as an index of the extent of electro-osmotic flow during the course of the various experiments. The ratio of the distance of electroosmotic flow and the distance of protein migration was shown to be constant for a given type of paper. For serum albumin on Munktell 20 paper this ratio was 0.35. A formula for mobilities applicable to liquid in a highly porous supporting medium is presented. Mobility values for human serum albumin at various pH levels on paper showed approximate agreement with those obtained in free solution giving a similar isoelectric point.

Fígado, veneno e sôro sanguíneo de "Bothrops jararaca" foram estudados por meio da eletroforese em papel e determinação de atividades enzimáticas. Xantina oxidase e deshidrogenase foram encontradas sòmente no fígado das cobras. A análise espectrográfica do veneno e do sôro confirmam os resultados negativos obtidos para xantina oxidase uma vez que não foi encontrado molibdêneo. L-amino ácido oxidase foi determinada no fígado, sÔro e veneno. A eletroforese em papel do sôro sanguíneo mostrou que existem 7 frações proteicas, sendo que duas apresentam fluorescência característica de flavinas, quando expostas à luz ultra-violeta. Em vista dos resultados obtidos é concluido que as flavinas do sôro e do veneno de Bothrops jararaca estão na maior parte ligadas às proteínas. Estas flavinas combinadas parecem estar sob a forma de FAD (flavina adenina dinucleotídeo) fazendo parte do grupo prostético da L-amino ácido oxidase, uma vez que não foi encontrada nenhuma atividade de xantina oxidase.

The growth inhibition test for identifying Mycoplasma species has been modified by drying antibody-impregnated paper discs at 5 C. When stored at −20 C, these discs have been found to retain their inhibitory activity for longer than 7 months. Since these discs can be stored for long period of time, significant advantages over present methods result. When, for example, discs are arranged on a ring, a single test can be used for the identification of an unknown human species. Valuable antisera can be distributed to other laboratories on paper discs in much less volume than can fluid antiserum. Considerable savings of time result from prior preparation of many discs that can then be stored and used over a long period of time. The growth-inhibiting antibody is stable, and the activity is not enhanced by a heat-labile accessory factor from fresh guinea pig serum which increases the antibody titer in the metabolic inhibition test.

Suspensions of chloroplasts isolated from leaves of spinach or peas and illuminated in suitable aqueous media are capable of both 02 evolution and CO2 fixation at rates comparable with those which occur in vivo (8, 11). Under these conditions the major radioactive products of photosynthetic "4CO2 assimilation are glycerate-3-P and dihydroxyacetone-P, a considerable proportion of which may be recovered from the medium outside the chloroplasts (3). It is still not clear what prevents metabolism of these early products of photosynthesis to hexose phosphates and compounds such as amino acids and sucrose. Recently we have suggested (6) that glycerate-3-P and DHAP1 accumulate in chloroplast suspensions simply because they diffuse from the plastids into the external medium where they cannot be metabolized further. We have shown that these compounds were not accumulated if the volume of medium in the experimental sample was reduced to a minimum by layering the chloroplasts on filter paper discs. Under these conditions the chloroplasts accumulated hexose-monoP and amino acids such as glycine and alanine but did not form significant amounts of sucrose. Factors controlling the biosynthesis of sucrose from CO2 in chloroplasts remain unknown. It is possible that the nature of the products formed by isolated chloroplasts could depend on the relative concentrations of intermediates of the photosynthetic carbon reduction cycle within the plastids. We have therefore investigated effects of preincubating chloroplasts with varying concentrations of glycerate-3-P and sugar phosphates on the distribution of radioactivity into the products of 14CO2 assimilation by spinach

Wright's model for the effects of random fluctuations in gene frequency in a population of fixed size is generalized to randomly fluctuating population size, and treated from the viewpoint of G. Malécot, using a martingale convergence theorem. The gene frequency approaches a limit, whose value depends on the actual realization, or history, of the process; that is, convergence is with probability one (or: almost surely) in statistical language. The limit does not necessarily represent a state of fixation of either allele; in particular, the limiting probability distribution is not necessarily trivial. For the special case of deterministically varying population size, a necessary and sufficient condition for such non-triviality is given.

Microbiological assay of individual antibiotics in mixtures of antibiotics depends on the use of selective inactivation and/or of test bacteria with differential susceptibility. Controlled experiments revealed that streptomycin in concentrations of 20 and 40 μg/ml did not influence a disk diffusion assay of penicillin with Sarcina lutea (ATCC 9341) as the test organism. In the case of penicillin concentrations less than or equal to 1 IU/ml, addition of 80 μg of streptomycin per ml influenced the penicillin assay significantly. Clinical use of streptomycin resulting in levels above 40 μg/ml usually did not occur; therefore penicillin could be assayed as though streptomycin were not present. We observed additionally that S. lutea was unable to grow on agar plates prepared with semicarbazide hydrochloride.

The method of E.V. Borutski was used for determining the production of chironomids, that is, the dynamics of the number and biomass of the larvae were analysed, their death, a calculation of emergence and the number of deposited egg layings was carried out. In addition to the method of Borutski, the authors also calculated the seasonal dynamics of the number of larvae of the younger age stages in the microbenthos. Translated from Russian into English

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