Effects of nitrogen,phosphorus and potassium fertilizers on the assimilation capacity ofBeta vulgaris chloroplasts (I)

Summary Aspects of non-cyclic photophosphorylation and NADP photoreduction,viz (a) the effects produced on these processes by the three fertilizer elements: nitrogen, phosphorus and potassium; (b) variations in the catalase activity of reaction mixtures following fertilizer application, and (c) correlations between photosynthesis as measured on leaf-tissue discs and the assimilation capacity of chloroplast suspension, were studied. The role of catalase in the non-cyclic photophosphorylation processes was also studied.While photophosphorylation is influenced chiefly by the level of available soil phosphorus, NADP reduction is affected by all three nutrients. In addition, there was a greater degree of significance, for diagnostic and application purposes, in the values obtained if these two activities were referred to the chloroplast count rather than to the chlorophyll content.Catalase activity, in addition to responding in a different way to the respective fertilizer treatments and, in particular to available soil nitrogen, was governed by the principal constituents of the reaction mixture and in a manner contrary to that of non-cyclic photophosphorylation as measured in terms of oxygen evolution.Experimental findings further showed that photosynthesis is correlated chiefly with NADP-reduction capacity.     

Statistical measurement of signal transmission in the central nervous system of the crayfish

Summary Transmission of nerve signals in the crayfish brain was studied by means of the transfer function derived from input-output analysis with random stimulation. The transfer function was measured in the form of frequency-response-function and represented by Bode plot. Two classes of the frequency-response-functions were discriminated, corresponding to two types of response patterns evoked by the constant frequency stimuli. The first type had the characteristics of a band pass filter similar to an underdamped resonant circuit. The second one had the characteristics of a phase lag circuit, occasionally, with additional small positive or negative peak at almost the same frequency as the resonance of the first type. A few possibilities for the resonance and the phase lag mechanisms were discussed.     

Die wachstumsfördernde Wirkung von Tannin auf Getreidekoleoptilen

Zusammenfassung Schwach konzentrierte Tanninlösungen (5·10^–5 bis 5·10^–8 molar) vermochten das Wachstum 10 mm langer Koleoptilabschnitte von 15 Kulturformen vonAvena sativa, Hordeum distichon, Hordeum vulgare, Zea mays, Triticum aestivum undSecale cereale um etwa 6–25% zu fördern. Die mögliche Beteiligung von Gerbstoffen am Streckungswachstum höherer Pflanzen wurde diskutiert.

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Summary The growth of 10 mm coleoptile sections of 15 cultivars ofAvena sativa, Hordeum distichon, Hordeum vulgare, Zea mays, Triticum aestivum andSecale cereale was stimulated by dilute tannin-solutions (5·10^–5 to 5·10^–8 molar) from 6 up to 25%. The possible role of tannins in elongation growth of higher plants was discussed.

     

Reduction of a Tetrazolium Salt in Determining Growth Activity of Yeast-Phase Histoplasma capsulatum

A colorimetric method using a tetrazolium compound, 3,4,5-dimethylthiozalil-(1 or 2),2,5-diphenyltetrazolium bromide (TTBr), was developed for studying the growth activity of yeast-phase Histoplasma capsulatum. Materials extracted in phosphate buffer, pH 7.0, from cells at different stages of growth reduced TTBr. Colorimetric changes were correlated with enzymatic activity. Under standardized conditions specified herein, the optical density of the reduced tetrazole was an index of the growth activity of the organism.     

Superinfection with R Factors by Transduction in Escherichia coli and Salmonella typhimurium

Superinfection immunity is found in the conjugal transfer of R factors between two fi(+) R factors and between two fi(-) R factors (fi = fertility inhibition), as we reported previously. In contrast, no reduction in the frequencies of transduction of an fi(+) R factor 222 was caused by the presence of fi(+) R factors in the recipients in transduction systems with phage P1kc in Escherichia coli K-12 and with phage P22 in Salmonella typhimurium LT-2. The absence of superinfection immunity in transduction may be due to the difference in the route of entry of the R factor. The frequencies of transduction of an fi(+) R factor were reduced, although slightly, by the presence of fi(-) R factors in the recipients. This reduction is probably due to host-controlled restriction of the entering fi(+) R factor by the fi(-) R factors in the recipients, since transduction of an fi(+) R factor by the transducing phage propagated on the strain carrying both fi(+) and fi(-) R factors was not reduced by the presence of homologous fi(-) R factors in the recipients. The fi(+) R factor 222, when transduced to the recipient strains carrying other R factors, recombined genetically at high frequencies with these resident R factors, regardless of their fi type.     

About phoma liliana Chandra & Tandon

Summary In vitro,Phoma liliana could not be distinguished from the later-describedP. ehretiae and two incidental isolates fromMangifera andChrysanthemum. Starting from the principle of the classification in the Deuteromycetes, our conclusion is that we must speak of one and the same form-species, which can be found on different plants.     

Studies on several genetic hematological traits of the Mexican population. XII. Distribution of blood group antigens in twelve Indian tribes

Blood samples from 1090 Mexican Indians belonging to the Chol, Chontal, Totonac, Huastec, Mixe, Mazatec, Zapotec, Mixtec, Chinantec, Nahua, Cora and Huichol linguistic groups, were obtained and examined in regard to the following blood group antigens: A, B. M, N, P, C, c, D, E, e, Fy(a), K and Di(a). The gene frequencies were similar to what has been described for other Amerindians; high values for O, M, CDe, cDE and Duffy; low to absent Kell and presence of Diego in variable amounts. The frequency of chromosomes CDE and cDe/cde was somewhat higher than usual and some of the tribes had relatively high frequencies of the A and B antigens. It was felt that variable degrees of non-Indian admixture was at least partially responsible for this situation. A previous study dealing with the distribution of abnormal hemoglobins and glucose-6-phosphate dehydrogenase deficiency in these same tribes, had strongly suggested the possibility of some Negro admixture in the Chontal, Nahua and Cora tribes. However, this was not specifically reflected in their blood group distribution. This served to emphasize the need of investigating as many markers as possible when trying to characterize a population.