1887

Abstract

SUMMARY: Growth of the detergent-degrading bacterium C12B on pyruvate supplemented with pure tetradecan-2-sulphate and tetradecan-2-ol together, led to induction of the S3 alkylsulphatase active towards symmetrical or near-symmetrical secondary alkyl sulphates. Induction was accompanied by disappearance of the tetradecan-2-sulphate surfactant and by the appearance of some of the S3 activity (up to 45% of the total) in the culture fluid. Induction did not occur when one or other or both of the C compounds was omitted from the minimal-pyruvate growth medium, nor with resting cell suspensions even with both compounds present. Provided that the pyruvate medium contained tetradecan-2-sulphate, good induction of S3 enzyme could also be achieved by replacing tetradecan-2-ol with any one of most secondary alcohols tested, including alkan-2-ols (C to C), symmetrical alcohols (C to C) and decanol isomers with the hydroxyl at C-3, C-4 or C-5. Primary alcohols were ineffective. Requirements for the ester component of the inducer combination were more closely defined; maintaining tetradecan-2-ol and pyruvate as constant components, no activity was detected with C, C or C alkan-2-sulphates, very feeble activity with C and C homologues, and increasing activity from C to C. Symmetrical and near-symmetrical alkyl sulphates (substrates of the S3 enzyme) and primary alkyl sulphates, all tested in combination with tetradecan-2-ol plus pyruvate, failed to induce significant amounts of S3 enzyme even at elevated concentrations. Critical micelle concentrations were measured for alkan-2-sulphates and correlated with co-inducer capacity and with the concentration dependence of induction by tetradecan-2-sulphate, which followed a hyperbolic saturation curve with co-inducer = 0.29 m (inducer concentration giving half-maximum induction). Successful induction was also achieved with tetradecan-2-sulphate alone (no alcohol added), but only in the absence of pyruvate, under which circumstances hydrolysis of tetradecan-2-sulphate to the parent alcohol occurred as a prerequisite to bacterial growth. The collective results suggested that induction required not only a combination of secondary alcohol and long-chain alkan-2-sulphate in appropriate amounts (concerted induction), but also that their presence was required at a particular time, when the cells were actively growing and dividing.

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/content/journal/micro/10.1099/00221287-132-3-727
1986-03-01
2019-10-18
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