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 McGavin, M Articles by Forsberg, C W Search for Related Content PubMed PubMed Citation Articles by McGavin, M Articles by Forsberg, C W Agricola Articles by McGavin, M Articles by Forsberg, C W

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1990 May; 56(5): 1235-1244

Regulation and distribution of Fibrobacter succinogenes subsp. succinogenes S85 endoglucanases.

Department of Microbiology, University of Guelph, Ontario, Canada.

ABSTRACT

The distribution of endoglucanase activities in cultures of Fibrobacter succinogenes subsp. succinogenes S85 grown on different carbon sources was examined by a variety of biochemical and immunological techniques. Total culture endoglucanase activity was primarily cell associated and was expressed constitutively, although synthesis of endoglucanase 1 (EG1) was repressed by cellobiose. Western immunoblotting showed that EG1 and EG3 were released into the culture fluid during growth, while EG2 remained largely associated with the cell. Subcellular localization showed low endoglucanase activity in the periplasmic fraction and similar, high levels in the cytoplasmic and membrane fractions. Western immunoblotting showed that EG2 was absent from the periplasmic fraction. Data from immunoelectron microscopy with either polyclonal or monoclonal antibody to EG2 revealed a high density of gold labeling at sites where there was a disruption in the regular features of the cell surface, such as in blebbing or physical tearing of the membrane. When cells were grown on cellulose, there was a high density of labeling on the cellulose but not on the cells, indicating that EG2 has limited exposure at the cell surface. On the basis of these data, export of enzymes from their intracellular locations appears to occur via three different mechanisms: a specific secretory pathway independent of cellulose, a secretory mechanism which is mediated by contact with cellulose, and a generalized blebbing process that occurs irrespective of the carbon source.

This article has been cited by other articles:

• Koike, S., Pan, J., Kobayashi, Y., Tanaka, K. (2003). Kinetics of In Sacco Fiber-Attachment of Representative Ruminal Cellulolytic Bacteria Monitored by Competitive PCR. J DAIRY SCI 86: 1429-1435 [Abstract] [Full Text]