Masters Degrees (Microbiology)

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Browsing Masters Degrees (Microbiology) by Subject "Alicyclobacillus"

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    Molecular characterization of Sulfobacillus and related organisms
    (Stellenbosch : Stellenbosch University, 2004-03) Schutte, Mart-Alet (Martha Aletta); Rawlings, D. E.; Stellenbosch University. Faculty of Science. Dept. of Microbiology.
    ENGLISH ABSTRACT: Thirteen Sulfobacillus strains from different geographical locations and two Alicyclobacillus strains were included in this study. These organisms proved to be moderately thermophillic (two different sets of optimal temperatures of 45°C and 55°C were found), Gram-positive, endospore forming bacteria. The pH optima of the strains tested was pH 2.5 and the pH range lay between pH 1.5 and pH 5.0. It was established that some strains of Sulfobacillus had the capacity for anaerobic growth when using ferric iron as an electron donor. It was determined that S. thermosuljidooxidans was the species found within South African biooxidation plants. Plasm ids were identified within strain 611 (S. thermosuljidooxidans) isolated from a Billiton commercial plant. The sample of Sulfobacillus strains used in this study could clearly be divided into two groups based on the analysis of their 16S rRNA gene sequences as well as the number of ribosomal (rm) operons present as determined by Southern hybridization. A system for the convenient identification of Sulfobacillus species was developed using several of the techniques employed in this study. Preliminary identifications can be obtained by restriction enzyme digestion of the PCR amplified 16S rRNA gene. Confirmation of this placement can be done by comparison of the 16S - 23S rRNA spacer region amplification band sizes. Once the preliminary identification has been completed it is possible to place the isolate in the correct species by making use of the differences in sugar utilization that the species exhibit. The more laborious method of 16S rRNA sequence comparisons can be undertaken if there is still any uncertainty as to which species an isolate belongs to. Phylogenetic results obtained from the 16S rRNA gene sequence indicates that the genus Sulfobacillus should probably be divided into two individual genera. Further information gathered from the phylogenetic comparisons indicates that strain Riv-14 previously assigned to S. ambivalens is more closely related to S. montseratensis. Data obtained from 16S - 23S rRNA spacer region analysis confirms this result. Future work includes the use of DNA-DNA hybridization studies and mol% G+C ratio's in order verify the presence of two distinct genera as well as placing Riv-14 within the correct species.