Regulation of sorbitol metabolism in <i>Clostridium pasteurianum</i>

Mitchell, Wilfrid J.; Roohi, M. Sadegh; Morrison, D. C.

doi:10.1042/bst0130936

Cited by 1 publication

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“…Induction of metabolism of the PTS substrate sorbitol was, however, prevented in the presence of glucose. The mechanism of regulation of sorbitol metabolism by glucose has been shown to involve inhibition of sorbitol accumulation by the cell (Booth & Morris, 1982;Mitchell et al, 1985), and a more extensive description of the mechanism of inhibition of sorbitol uptake by glucose will be presented elsewhere (M. S. Roohi & W. J. Mitchell, unpublished work).…”

Section: Resultsmentioning

confidence: 99%

“…1 b). Nevertheless, despite the fact that the rate of utilization of glucose and sorbitol was similar, experiments following the incorporation of 14C-labelled carbohydrates have indicated a strong preference for glucose (Mitchell et al, 1985), demonstrating that carbon derived from glucose is preferentially incorporated into cellular material.…”

Section: Utilization Of Glucose and Other Pts Sugarsmentioning

confidence: 99%

“…The implication of these results is that, in uninduced cells, sorbitol is effectively excluded in the presence of glucose. Partial inhibition of sorbitol uptake by glucose and the analogue methyl aglucoside has in fact been demonstrated in fully induced cells (Booth & Morris, 1982;Mitchell et al, 1985). The extent of the inhibition is now known to be dependent on the ability of the sorbitol PTS to compete with the glucose PTS for a common energy pool (M. S. Roohi & W. J.…”

Section: W J Mitchell and O T H E R Smentioning

confidence: 99%

“…Cells growing exponentially in defined mineral salts medium containing excess (2%, w/v) carbon source were harvested and washed with 50 mM-potassium phosphate buffer, pH 7.0, containing 0.1% (w/v) L-cysteine hydrochloride. Activity of the sorbitol PTS was measured by following the rate of phosphorylation of ['SC]sorbitol in cells permeabilized by treatment with toluene (Mitchell & Booth, 1984;Mitchell et al, 1985). Cell suspensions were supplemented with 5 mM-MgC1, and 0-5 mM-PEP, and after a 5 min equilibration period at 37 "C, ['4C]sorbitol [l mCi mmol-' (37 MBq mmol-I)] was added to a concentration of 0.1 mM.…”

Section: E T H O D Smentioning

confidence: 99%

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Regulation of Carbohydrate Utilization in Clostridium pasteurianum

Mitchell¹,

Roohi²,

Mosely³

et al. 1987

Microbiology

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Clostridium pasteurianum is capable of fermentative growth on a number of carbohydrate compounds. Several, including glucose, fructose and sorbitol, are accumulated via a phosphoenolpyruvate-dependent phosphotransferase system (PTS), while the uptake of galactose and gluconate is protonmotive-force-dependent. We have examined the utilization of these substrates by cultures of C. pasteurianum growing on carbohydrate mixtures to determine whether the organism displays preferences for one carbon source over the others; such a preference may indicate the operation of specific mechanisms for regulation of carbohydrate metabolism. In most cases the carbohydrates were co-metabolized. Glucose was utilized together with fructose, gluconate and galactose, although galactose appeared to be favoured over glucose. This preference was not due to repression of synthesis of the glucose PTS. On the other hand, glucose prevented induction of the sorbitol PTS, and led to strong inhibition of sorbitol utilization in uninduced cells. Pre-adaptation of cells to growth on sorbitol counteracted the inhibition by glucose resulting in utilization of glucose and sorbitol at approximately equal rates.

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Section: Resultsmentioning

confidence: 99%

Section: Utilization Of Glucose and Other Pts Sugarsmentioning

confidence: 99%

Section: W J Mitchell and O T H E R Smentioning

confidence: 99%

Section: E T H O D Smentioning

confidence: 99%

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