Symbiotic interaction of Rhizobium with roots of legume plants leads to the formation of root nodules that are capable of reducing atmospheric nitrogen. In nodule cells, bacteria are always enclosed inside the peribacteroid membrane (pbm) which is derived from the plant cell plasma membrane. The pbm mediates all the molecular exchanges between the host plant and bacteria. The pbm of soybean (Glycine max) nodules induced by Bradyrhizobium japonicum was characterized for the presence of nodule-specific proteins (nodulins), which may be involved in some of the nodule-specific roles the pbm plays. The pbm was found to contain a number of nodulins, and most of them were shown to be of plant origin. The peribacteroid fluid (pbf) was also purified and shown to contain nodulins. Some of the pbf proteins were highly glycosylated. Immunological localization at the electron microscopic level has shown that pbm nodulins are inserted specifically in the pbm; almost none are detected in the plasma membrane (pm) of infected cells even though the pbm is derived from it. The amino acid sequences of three different pbm nodulins (nodulin-23, -24 and -26) do not share significant primary structure homology, neither do their tentative secondary structures. Our results do not preclude targeting based on pbm-nodulin-specific feature(s) of the proteins; but it is possible that pbm-specific localization is achieved by differential rates of membrane synthesis, or turnover, in pbm as compared to the plasma membrane.

This study investigated possible reasons for the failure of the acetylene inhibition assay of denitrification in highly reducing environments and resulted in the isolation of a denitrifying Cytophaga from soil enriched by anaerobic incubation with glucose, nitrous oxide (N(,2)O), acetylene (C(,2)H(,2)), and sulfide (S('2-)). Such soil enrichments and pure cultures of the isolated Cytophaga (Is-11) reduced N(,2)O rapidly even in the presence of a normally inhibitory concentration of C(,2)H(,2) (4 kPa), providing S('2-) was present 8.0 umol (g soil)('-1) or 0.4 umol (mL culture)('-1) . The observed reaction appears to be unique to this soil Cytophaga since other organisms tested, using the same or similar experimental conditions, failed to show this response. / The isolate was characterized, after extensive comparative studies with five Cytophaga johnsonae strains, as a pigmented, Gram-negative, non-motile, gliding filamentous bacillus. Although these features established a taxonomic link with the family Cytophagaceae, the inability of Is-11 to digest chitin and DNA base composition of about 42.5 mol% (G+C) make the organism's specific affiliation uncertain.

xxix, 283 leaves : ill. ; 25 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agricultural Biochemistry and Soil Science, 1974

Thesis (Ph.D.) -- University of Adelaide, Dept. of Agricultural Biochemistry and Soil Science, 1974.

Thesis (Ph.D)--Murdoch University, 2008. / Thesis submitted to the Faculty of Sustainability, Environmental and Life Sciences. Includes bibliographical references (p. 213-220).

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 124-143). Also available in print.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

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