A Comparison of the Characteristics of Extracellular Protein Secretion by a Gram-Positive and a Gram-Negative Bacterium

Coleman, G.; Abbas-Ali, B.; Sutherland, John P.; Fyfe, Lorna; Finley, Andrew O.

doi:10.1007/978-1-4684-1274-1_2

Cited by 3 publications

(3 citation statements)

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“…amino acids as found in investigations with isolated bacterial strains (Coleman et al 1987) as well as with lake-water samples (Chrost 1991). This effect is caused by the reduction in the affinity of mRNA for a promoter, causing a decrease in enzyme formation.…”

Section: Discussionmentioning

confidence: 81%

“…This effect is caused by the reduction in the affinity of mRNA for a promoter, causing a decrease in enzyme formation. In addition, the activity of an enzyme can be regulated by the effect of competition (Coleman et al 1987) when catabolites stimulating growth are present in high amounts shifting the cell metabolism towards growth. This inhibits enzyme production by changing the concentrations of the cellular components involved in the regulation of transcription.…”

Section: Discussionmentioning

confidence: 99%

“…Most of the extracellular hydrolytic enzymes are regulated by substrate induction, catabolite repression or competition (Priest 1984, Coleman et al 1987. Investigations with natural mixtures of microbial organisms from freshwater (Chrost & Overbeck 1990) and marine environments (Koster et al 1991) showed that the microbial communities reacted to altered substrate availability by significant changes in enzyme production.…”

Section: Introductionmentioning

confidence: 99%

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Regulation of microbial enzymatic degradation of organic matter in deep-sea sediments

Boetius¹,

Lochte²

1994

Mar. Ecol. Prog. Ser.

132

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The enzymatic response of a natural deep-sea microbial community to input of organic matter was investigated by substrate enrichment experiments. Sediments from the BIOTRANS area at 47"N 20°W in the NE Atlantic (4500 m depth) were supplied with particulate and dissolved organic matter from stenhzed net plankton and incubated under in situ pressure and temperature. Changes in the potential hydrolytic activities of the extracellular enzymes a-and P-glucosidase, chitobiase, lipase and aminopeptidase were observed over a 15 d incubation period. Direct microscopic counts and phospholipid concentrations were used as measures of microbial biomass. Induction of enzyme production proportional to the supply of organic matter was found for enzymes degrading structural polysaccharides (P-glucosidase, chitobiase), while aminopeptidase activity was Inhibited and no clear effect was found for enzymes degrading storage compounds (a-glucosidase and lipase). Particulate organic matter induced higher enzyme production than equivalent amounts of dissolved organic matter. Only a slight increase in microbial biomass was observed until the end of the experiment after 15 d indicating that changes in enzyme activity were not due to bacterial growth. The observations give evidence that the production of enzymes in natural mixed microbial communities is directly regulated by the supply of appropriate food.

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Section: Discussionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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