Doctoral Degrees (Microbiology)

Permanent URI for this collection

https://scholar.sun.ac.za/handle/10019.1/3627

Browse

Browsing Doctoral Degrees (Microbiology) by browse.metadata.advisor "Chenia, H. Y."

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Comparative proteomic and genomic analysis of Flavobacterium johnsoniae-like biofilm, planktonic and agar surface-associated cells
    (Stellenbosch : University of Stellenbosch, 2010-03) Flemming, Leonard; Chenia, H. Y.; Rawlings, D. E.; University of Stellenbosch. Faculty of Science. Dept. of Microbiology.
    ENGLISH ABSTRACT: Pathogenic Flavobacterium spp. cause serious disease outbreaks in a variety of farmed fish, which lead to large economic losses in the aquaculture industry on an annual basis. The ability of Flavobacterium johnsoniae-like isolates to grow as surface-associated communities (biofilms) in aquaculture systems poses a threat to fish health over extended periods of time. The biofilmforming ability of 28 F. johnsoniae-like isolates obtained from diseased fish were correlated with their chitin-degrading abilities and extracellular carbohydrate complexes (ECC) and their pulsed-field gel electrophoresis (PFGE) genotypes. Physiological changes in the proteome of 5 day planktonic, biofilm and agar surface-associated cultures of F. johnsoniae-like isolates YO12 and YO64 were analyzed by two-dimensional (2-D) gel electrophoresis and 17 differentially expressed and 14 uniquely expressed proteins were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Thirty-two differentially expressed genes in 5 day biofilm and agar surface-associated cultures of F. johnsoniae-like isolates YO12 and YO64 were identified using suppression subtractive hybridization (SSH). Significant negative correlations were observed between the chitin-degrading abilities and ECC and the biofilmforming capacity of 24 h biofilm cultures of F. johnsoniae-like isolates. Genetic heterogeneity was displayed by the F. johnsoniae-like isolates following PFGE. A significant positive correlation was observed between PFGE types and fish host species. Differentially and uniquely expressed proteins identified in planktonic, biofilm and agar surface-associated phases by 2-D/MS as well as differentially expressed genes identified in the biofilm and agar surface-associated phases by SSH were categorized as being involved in adaptation/protection, metabolic processes, membrane/transport/ motility and transcription/ translation. As far as we know, this is the first report on the characterization of differentially expressed genes and gene products of F. johnsoniae-like isolates obtained from diseased fish in South Africa.