The bdellovibrios are gram-negative bacteria which prey upon other gram-negative bacteria. They are found in a variety of habitants and likely represent a significant biological control of gram-negative bacteria in the environment. They attach to the surface of their prey, traverse the outer membrane and peptidoglycan, and establish residence in the periplasmic space. Here they execute a program of highly efficient biochemical processes which results in the proliferation of the bdellovibrios at the expense of the prey. The proposed research is a continuation of recent studies which show that Bdellovibrio recruits intact outer membrane proteins from the prey. These prey-derived proteins are inserted into the outer membrane of the Bdellovibrio. The mechanism accounting for this novel process of protein mobilization and relocalization will be examined by attempting to select mutants defective in this process, and by employing E. coli prey which express structurally altered porins. If mutant proteins are found which fail to be acquired by the bdellovibrios, the structural alterations in the proteins will be assessed from peptide maps and from peptide sequencing techniques. The possible role of donor and recipient membrane fluidities also will be examined to assess their significance in the relocalization process. The outlined experiments along with a series of descriptive experiments designed to correlate protein acquisition with other known biochemical events of the Bdellovibrio life-cycle are expected to provide sufficient information to permit the formulation of hypothetical mechanisms which can be tested experimentally. This research is anticipated to provide a unique approach to evaluating structure-function relationships in membrane proteins. Additionally, it is anticipated that the proposed research will make a significant contribution to revealing the biochemical basis of predation by Bdellovibrio.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM034838-01S1
Application #
3286529
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1986-09-01
Project End
1988-08-31
Budget Start
1986-09-01
Budget End
1988-08-31
Support Year
1
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Louisiana State University Hsc New Orleans
Department
Type
School of Medicine & Dentistry
DUNS #
782627814
City
New Orleans
State
LA
Country
United States
Zip Code
70112
Flores, B M; Batzer, M A; Stein, M A et al. (1993) Structural analysis and demonstration of the 29 kDa antigen of pathogenic Entamoeba histolytica as the major accessible free thiol-containing surface protein. Mol Microbiol 7:755-63
Gordon, R F; Stein, M A; Diedrich, D L (1993) Heat shock-induced axenic growth of Bdellovibrio bacteriovorus. J Bacteriol 175:2157-61
Reed, S L; Flores, B M; Batzer, M A et al. (1992) Molecular and cellular characterization of the 29-kilodalton peripheral membrane protein of Entamoeba histolytica: differentiation between pathogenic and nonpathogenic isolates. Infect Immun 60:542-9
Stein, M A; McAllister, S A; Torian, B E et al. (1992) Acquisition of apparently intact and unmodified lipopolysaccharides from Escherichia coli by Bdellovibrio bacteriovorus. J Bacteriol 174:2858-64
Fralick, J A; Diedrich, D L; Casey-Wood, S (1990) Isolation of an Lc-specific Escherichia coli bacteriophage. J Bacteriol 172:1660-2
Stein, M A; McAllister, S A; Johnston, K H et al. (1990) Detection of lipopolysaccharides blotted to polyvinylidene difluoride membranes. Anal Biochem 188:285-7
Diedrich, D L; Stein, M A; Schnaitman, C A (1990) Associations of Escherichia coli K-12 OmpF trimers with rough and smooth lipopolysaccharides. J Bacteriol 172:5307-11
Diedrich, D L (1988) Bdellovibrios: recycling, remodelling and relocalizing components from their prey. Microbiol Sci 5:100-3
Talley, B G; McDade Jr, R L; Diedrich, D L (1987) Verification of the protein in the outer membrane of Bdellovibrio bacteriovorus as the OmpF protein of its Escherichia coli prey. J Bacteriol 169:694-8