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Identification of Glycine as the Factor in Peptone Which Induces Pleomorphism in Azotobacter Vinelandii

The rigid peptidoglycan layer of the cell wall is responsible for maintaining the structural integrity of bacteria. Antibiotics such as penicillin exert their anti-bacterial effect by inhibiting synthesis of peptodoglycan, and enzymes such as lysozyme destroy cell integrity by hydrolyzing specific bonds in the interior of this macromolecule. Defective cells can no longer withstand the high turgor pressure within the cell because they are no longer protected by a rigid wall and tend to become fragile and spherical or irregular in shape. While all bacteria are pleomorphic under certain conditions which do not normally affect other bacteria. This is exemplified by the pleomorphic growth of Azotobacter in nutrient agar or peptone-containing medium. The purpose of this investigation was to study the nature of peptone-induced pleomorphism of Azotobacter. The first phase of study dealt with the effects of poptone on the growth and morphology of A. vinelandii. Many diverse froms were observed in peptone-containing media, but it was shown that all cell types were related to the "fungoid" family of pleomorphic cells. Although Azotobacter failed to accumulate detectable levels of cell-wall precursors in response to glycine treatment, it was shown that glycine acted only on metabolically active cells. In addition, incorporation of glycine into cell wall of Azotobacter was not required for induction of pleomorphism. Methionine and aspartic acid, and to a lesser degree alanine and isoleucine, were found to competitively inhibit glycine toxicity.

Identiferoai:union.ndltd.org:unt.edu/info:ark/67531/metadc935735
Date12 1900
CreatorsRosenthal, Raoul Simon
ContributorsVela, G. Roland, 1927-, Gracy, Robert W., Bass, Joe A., Harris, Ben G., Masaracchia, Ruthann A.
PublisherNorth Texas State University
Source SetsUniversity of North Texas
LanguageEnglish
Detected LanguageEnglish
TypeThesis or Dissertation
Formatvii, 123 leaves : ill., Text
RightsPublic, Rosenthal, Raoul Simon, Copyright, Copyright is held by the author, unless otherwise noted. All rights

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