This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Galperin, M. Y. Articles by Romano, A. H. Search for Related Content PubMed PubMed Citation Articles by Galperin, M. Y. Articles by Romano, A. H. Agricola Articles by Galperin, M. Y. Articles by Romano, A. H.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., Mar 1997, 969-972, Vol 63, No. 3
Copyright © 1997, American Society for Microbiology

Coregulation of beta-galactoside uptake and hydrolysis by the hyperthermophilic bacterium Thermotoga neapolitana

MY Galperin, KM Noll and AH Romano
Department of Molecular and Cell Biology, The University of Connecticut, Storrs, Connecticut 06269-3125

Regulation of the beta-galactoside transport system in response to growth substrates in the extremely thermophilic anaerobic bacterium Thermotoga neapolitana was studied with the nonmetabolizable analog methyl-beta-D-thiogalactopyranoside (TMG) as the transport substrate. T. neapolitana cells grown on galactose or lactose accumulated TMG against a concentration gradient in an intracellular free sugar pool that was exchangeable with external galactose or lactose and showed induced levels of beta-galactosidase. Cells grown on glucose, maltose, or galactose plus glucose showed no capacity to accumulate TMG, though these cells carried out active transport of the nonmetabolizable glucose analog 2-deoxy-D-glucose. Glucose neither inhibited TMG uptake nor caused efflux of preaccumulated TMG; rather, glucose promoted TMG uptake by supplying metabolic energy. These data show that beta-D- galactosides are taken up by T. neapolitana via an active transport system that can be induced by galactose or lactose and repressed by glucose but which is not inhibited by glucose. Thus, the phenomenon of catabolite repression is present in T. neapolitana with respect to systems catalyzing both the transport and hydrolysis of beta-D- galactosides, but inducer exclusion and inducer expulsion, mechanisms that regulate permease activity, are not present. Regulation is manifest at the level of synthesis of the beta-galactoside transport system but not in the activity of the system.

This article has been cited by other articles:

• Silva, Z., Sampaio, M.-M., Henne, A., Bohm, A., Gutzat, R., Boos, W., da Costa, M. S., Santos, H. (2005). The High-Affinity Maltose/Trehalose ABC Transporter in the Extremely Thermophilic Bacterium Thermus thermophilus HB27 Also Recognizes Sucrose and Palatinose. J. Bacteriol. 187: 1210-1218 [Abstract] [Full Text]  
• Chhabra, S. R., Shockley, K. R., Conners, S. B., Scott, K. L., Wolfinger, R. D., Kelly, R. M. (2003). Carbohydrate-induced Differential Gene Expression Patterns in the Hyperthermophilic Bacterium Thermotoga maritima. J. Biol. Chem. 278: 7540-7552 [Abstract] [Full Text]  
• Nanavati, D., Noll, K. M., Romano, A. H. (2002). Periplasmic maltose- and glucose-binding protein activities in cell-free extracts of Thermotoga maritima. Microbiology 148: 3531-3537 [Abstract] [Full Text]