• Volume 47, Issue 1

      January 1958,   pages  1-54

    • Search for ratoon stunting disease of sugarcane in Bihar

      K L Khanna S L Sharma R C Srivastava J N Sinha

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      1. The latest findings about the disease as regards its symptoms and causal agent are summarised.

      2. Observations made on 26 varieties in 8 factory reserved areas and Research Farms at Pusa and Patna in February–March 1955 showed that its two main symptoms, namely the discoloration of vascular bundles at nodes and the reduction in length of stalks without a corresponding decrease in their girth, were generally absent.

      3. Experimental work with the stunted material of six varieties showed that (a) it gained both in length and girth of stalks when it was planted without any treatment but given optimum conditions of growth and (b) that the juice of these stunted canes failed to transmit the virus to healthy material.

      4. (a) The percentage of blocked vascular bundles also fell when the stunted material was grown under favourable conditions and (b) there was no rise when healthy material was brought in close contact with the diseased (?) juice.

      5. It may, therefore, be stated for the present that there is little likelihood of the disease being present in the State. Careful watch, however, is beeing maintained.

    • Studies on Indian ichneumonidæ (Hymenoptera) Subfamily: Gelinae - Part I. Tribes Gelini and Echthrini

      E S Narayanan Kundanlal

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    • Evaluation of staining procedures following fixation of yeast in iodine formol acetic solution

      Saraswathy Royan

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      1. Fixation for sixty to ninety minutes in Gram’s iodine diluted with an equal quantity of water and incorporated with formaldehyde and glacial acetic acid gives a life-like preservation of the cellular structures except for the overall reduction in the size of the cells.

      2. The necessity for the removal of RNA by acid hydrolysis as a preliminary but essential step to the succeeding staining procedures is emphasized. Judged from stained preparations there is little difference between extraction of RNA with normal HCl at 60° C. or with 10% perchloric acid at 28° C.

      3. The structure of the nucleus in carefully stained hæmatoxylin preparations are superposable on those seen in living cells under phase contrast. While euco-basic fuchsin tints only a limited region of the nucleus, the details revealed by the Giemsa stain are intermediate between Feulgen and hæmatoxylin preparations.

      4. The nucleus occupies an extra-vacuolar position. The vacuole is Feulgen negative and is therefore a cytoplasmic inclusion.

    • Studies in pectic enzymes of parasitic fungi - I. Secretion of protopectinase enzyme byPythium de Baryanum hesse on different potato media

      S C Gupta

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      Potato decoction and extracted sap of frozen potato tubers form good media for the production of protopectinase enzyme byPythium de Baryanum Hesse, the latter medium being better as it could be diluted to half-strength without losing its quality. Minced potato extract is not suitable medium for enzyme secretion, the reason might be oxidation of certain compounds present in plant tissues.

      The amount of growth of the mycelium has no relation with the protopectinase enzyme production.

    • Non-acetylation of sulfanilamide during acquirement of drug resistance inBacillus subtilis

      Sudha Joshi A Sreenivasan

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      Cells of susceptible and sulfanilamide-resistant strains ofBacillus subtilis were harvested under various cultural conditions and examined for their ability, if any, to acetylate sulfanilamide.

      The effects of added acetate, citrate and accessory factors such as pantothenic acid and methionine were studied.

      Experiments were also carried out employing cells enriched with glucose, phosphate and pantothenic acid.

      The results showed no measurable acetylation of sulfanilamide in all cases.

      A diazotizable arylamine accumulated in the culture filtrates of 0·5 per cent. sulfanilamide-resistant strain, but not of the susceptible strain, during growth of the organism and even in the absence of added sulfanilamide.

      It is concluded that detoxification of sulfonamides through acetylation is not the mechanism of drug resistance inB. subtilis. There is also no adaptive enzyme formation for the detoxification or utilization of sulfanilamide during acquisition of drug resistance.

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