Thesis (PhD(Microbiology))--University of Stellenbosch, 2010. / 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. / AFRIKAANSE OPSOMMING: Patogene Flavobacterium spp. veroorsaak ernstige infeksie uitbrake in ’n
verskeidenheid gekweekte vissoorte, wat jaarliks tot groot ekonomiese
verliese in die akwakultuur bedryf lei. Die vermoë van Flavobacterium
johnsoniae-tipe isolate om as oppervlak-gehegde gemeenskappe (biofilms) in
akwakultuur sisteme te groei bedreig visgesondheid oor verlengde periodes.
Die vermoë van 28 F. johnsoniae-tipe isolate om biofilms te vorm is vergelyk
met hul vermoë om chitien te degradeer, die profiel van hul ekstrasellulêre
koolhidraat komplekse (EKK) en bandpatrone verkry met puls-veld jel
elektroforese (PVJE). Fisiologiese veranderinge in die proteoom van 5-dagoue
planktoniese-, biofilm- en agar oppervlak-geassosieerde kulture van F.
johnsoniae-tipe isolate YO12 en YO64 is met twee-dimensionele (2-D) jel
elektroforese geanaliseer. Sewentien differensieël uitgedrukte en 14 uniek
uitgedrukte proteïene is deur middel van matriks-geassisteerde laser
desorpsie ioniserings-tyd van vlug-massa spektrometrie (MGLDI-TVV MS)
geïdentifiseer. Twee-en-dertig differensieël uitgedrukte gene in 5-dag-oue
biofilm- en agar oppervlak-geassosieerde kulture van F. johnsoniae-tipe
isolate YO12 en YO64 was deur middel van suppressie afgetrokke
hibridisasie (SAH) geïdentifiseer. Beduidende negatiewe korrelasies is tussen
die chitin-degraderings vermoë en EKK en die biofilm-vormings kapasiteit van
24-uur-oue biofilm kulture van F. johnsoniae-tipe isolate waargeneem.
Resultate verkry met PVJE het die heterogene samestelling van F.
johnsoniae-tipe isolate uitgewys. ‘n Beduidende positiewe korrelasie is tussen
PVJE groeperings en vis gasheer spesie waargeneem. Differensieël en uniek
uitgedrukte gene geidentifiseer in die planktoniese-, biofilm- en agar
oppervlak-geassosieerde fases is deur middel van 2-D/MS asook differensieël
uitgedrukte gene geïdentifiseer in die biofilm en agar oppervlakgeassosieerde
fases deur middel van SAH was as betrokke by
aanpassing/beskerming, metaboliese prosesse, membraan/vervoer/
beweeglikheid en transkripsie/translasie gekategoriseer. Sover bekend is
hierdie die eerste beskrywing van differensieël uitgedrukte gene en
geenprodukte van F. johnsoniae-tipe isolate afkomstig van geinfekteerde vis
in Suid Afrika.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/4020 |
| Date | 03 1900 |
| Creators | Flemming, Leonard |
| Contributors | Chenia, H. Y., Rawlings, D. E., University of Stellenbosch. Faculty of Science. Dept. of Microbiology. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Format | 214 p. : ill. |
| Rights | University of Stellenbosch |
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