Browsing by Author "Robb, Frank T"

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    Characterization and regulation of serine exoproteases and collagenase in vibrio alginolyticus
    (1982) Hare, Patricia; Woods, David R; Robb, Frank T
    The production of an extracellular collagenase and serine proteases by Vibrio alginolyticus during stationary phase was inhibited by a temperature shift from 30 to 37°C and by lack of oxygen. V. alginolyticus had identical growth rates at 30 and 37°C. Aeration did not affect the growth rate of stationary phase cells when the exoproteases were being produced. Macromolecular synthesis in stationary phase cells was not affected by temperature. The regulation of exoprotease production by temperature and oxygen is specific and has implications regarding the ecology of V. alginolyticus. The synthesis of a 100 000 molecular weight protein was induced in V. alginolyticus by either raising the temperature from 30 to 37°C, a lack of oxygen or (NH₄)₂SO₄. Histidine stimulated synthesis of a 52 000 molecular weight protein. The possibility that these proteins have a regulatory role in exoenzyme synthesis is discussed.
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    Genetic and biochemical studies of Vibrio alginolyticus glutamine synthetase
    (1988) Maharaj, Romilla; Woods, David R; Robb, Frank T
    A genomic library of the collagenolytic Vibrio alginolyticus strain was established in Escherichia coli HB101 employing the positive selection vector pEcoR251. A glutamine synthetase (GS) gene, glnA was identified by complementation of the glnA deletion in E. coli ET8051 glnA, glnL, glnG deletion strain. The glnA region of V. alginolyticus was cloned on a 5.7 kb insert in pRM210.
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    Molecular biology studies on the extracellular serine proteases of Vibrio alginolyticus
    (1989) Deane, Shelly May; Woods, David R; Robb, Frank T
    Vibrio alginolyticus is a gram-negative aerobic bacterium that produces several extracellular serine proteases and a collagenase during the stationary growth phase. The aim of this study was to investigate alkaline serine protease production by this organism, and to attempt the cloning and expression of a V.alginolyticus protease gene in Escherichia coli.
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    Physiological and ecological studies of mannitol utilizing marine bacteria
    (1985) Davis, Claire Louise; Robb, Frank T
    Bacteria were isolated from the kelp beds on the West Coast of South Africa. Strains isolated from the water column and kelp fronds were classified as Pseudomonas, Vibrio, Acinetobacter and Flavobacterium species. Bacterial diversity in adjacent kelp dominated habitats was examined using numerical analysis, and it was found that nearshore and offshore isolates were similar, whereas bacteria isolated from beached kelp and interstitial waters were dissimilar from them and from each other. Changes in numbers of bacteria able to form colonies on plates were monitored during upwelling and downwelling conditions.
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    Studies on the regulation of extracellular collagenase production by vibrio alginolyticus
    (1981) Reid, Graham Charlton; Woods, David R; Robb, Frank T
    Vibrio alginolyticus synthesized extracellular collagenase in a highly aerated peptone medium at the late-exponential and early-stationary phases of growth. Collagenase synthesis was subject to end-product repression and was repressed by various amino acids and ammonium ions. Glutamine caused severe repression of collagenase production. Collagenase synthesis was sensitive to catabolite repression by glucose and a number of carbon sources. Cyclic AMP, dibutyryl cyclic AMP and cyclic GMP did not relieve catabolite repression. Glucose and 2-deoxyglucose caused a severe transient repression. No intracellular preformed collagenase was detected and collagenase production ceased when induced cells were washed and resuspended in buffer.Trypsin and a-chymotrypsin had no effect on collagenase production by cells or sphaeroplasts. The inducers of collagenase production in peptone were shown to have abroad molecular weight range between 1, 000 and 60,000. The peptone inducers supported slow growth of V. alginolyticus when supplied as the sole nitrogen source in minimal medium. Digestion of the peptone inducers with purified V. alginolyticus collagenase resulted in a decrease in their inducing ability,whereas digestion with trypsin or a-chymotrypsin did not. Peptone acted as an inhibitor of collagenase.