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R J Rennie

Publications and source records attributed to R J Rennie.

5 recordsLinked to original sources
PubMed1981

A single medium for the isolation of acetylene-reducing (dinitrogen-fixing) bacteria from soils.

A single medium, containing standard basal salts and three common carbon sources (sucrose, mannitol, and sodium lactate) is proposed to replace nitrogen-free media in common use for isolating dinitrogen-fixing bacteria. Eight commonly isolated genera of dinitrogen-fixing bacterial exhibited growth on this combined carbon medium that equalled or bettered growth on other carbon-containing media. Combined carbon medium also yielded the highest counts of putative dinitrogen-fixing bacteria from three southern Alberta soils. A survey of the bacteria isolated aerobically from the Burdett soil on combined carbon agar indicated that, at higher dilutions, 75% of the isolates exhibited acetylene reduction. These bacteria were identified as Azospirillum spp., Bacillus polymyxa, B. macerans, Klebsiella pneumoniae, Erwinia herbicola, and Enterobacter cloacae. The inclusion of yeast extract in combined carbon medium is considered essential to supply organic growth factors and may supply "starter" nitrogen that promotes growth without inhibiting acetylene reduction.

Acetylene↗
PubMed1980

Dinitrogen-fixing bacteria: computer-assisted identification of soil isolates.

Dinitrogen-fixing (acetylene-reducing) bacteria may be readily isolated from soils but extensive biochemical or immunobiological testing, or both, are required to identify them absolutely. A computer-assisted scheme for identification of nine genera of dinitrogen-fixing bacteria was developed and tested. The computer program is based on interpretation of the 70 biochemical tests of the API 20E and 50E, supplemented with tests for acetylene reduction, nitrate and nitrite reduction, catalase, oxidase, motility, and growth on MacConkey's bile salt medium. Dinitrogen-fixing Enterobacteriaceae (Klebsiella pneumoniae, Enterobacter cloacae, and Erwinia herbicola) were accurately identified using the data base in the API analytical profile index. Nonenteric dinitrogen-fixing bacteria (Azotobacter spp., Azospirillum spp., Derxia sp., Rhodospirillum sp., Clostridium sp., and Bacillus spp.) were subjected to these tests to form a new data base for these bacteria. The API tests agreed with standard biochemical tests commonly used to identify these bacteria, were reproducible with time, and were sufficiently unique to permit accurate identification of each species. The use of the API 20E and 50E tests plus the additional seven tests with these known data bases permitted rapid and precise identification of acetylene reducing bacteria from various agricultural ecosystems.

Acetylene↗
PubMed1977

Immunofluorescence studies of Nitrobacter populations in soils.

Certain steps of a protocol to enumerate a bacterium directly in soil by immunofluorescence were studied with respect to the enumeration of Nitrobacter in soils of diverse properties. Maximal counts of Nitrobacter were obtained by varying factors involved in the release of bacteria from the soil. Differences with respect to these factors were related to soil-colloidal properties. Enumeration protocols modified with regard to soil properties were used with strain-specific fluorescent antibodies (FA) to enumerate Nitrobacter populations (a) in soil during storage, (b) in comparison with most probable number (MPN) enumeration, and (c) occurring in a spectrum of soil samples. FA counting was rapid and precise and gave counts generally 10- to 100-fold higher than obtained by MPN. Nitrobacter cells of the two serotypes studied, designated as agilis and Winogradsky, occurred in each soil at levels of 10(4)-10(5) per gram.

Bacteriological Techniques↗
PubMed1976

Immunofluorescence detection of nitrogenase proteins in whole cells.

Fluorescent antibodies (FA) prepared against the Mo-Fe and Fe proteins of nitrogenase from Klebsiella pneumoniae M5aI were used to detect these protein components in toluene-treated whole cells that were actively reducing acetylene. The FA were highly specific, staining only nitrogenase component proteins originating from Klebsiella. Cross-reactions between the FA and purified nitrogenase proteins from other dinitrogen-fixing micro-organisms did not occur, except in the case of Bacillus polymyxa. The tests rapidly and accurately assayed the component proteins in Klebsiella mutants and derivatives to which Klebsiella nif genes had been transferred either by plasmid or by other means. Cross-reactions also indicated the degree of relatedness between nitrogenase proteins from dinitrogen-fixing micro-organisms of various origins.

Bacteria↗