Periplasmic enzymes in Bdellovibrio bacteriovorus and Bdellovibrio stolpii

Abstract

When cells of either Bdellovibrio bacteriovorus 109J or Bdellovibrio stolpii UKi2 were subjected to osmotic shock by treatment with sucrose-EDTA and MgCl2 solutions, only trace amounts of proteins or enzyme activities were released into the shock fluid. In contrast, when nongrowing cells were converted to motile, osmotically stable, peptidoglycan-free spheroplasts by penicillin treatment, numerous proteins were released into the suspending fluid. For both species, this suspending fluid contained substantial levels of 5'-nucleotidase, purine phosphorylase, and deoxyribose-phosphate aldolase. Penicillin treatment also released aminoendopeptidase N from B. bacteriovorus, but not from B. stolpii. Penicillin treatment did not cause release of cytoplasmic enymes such as malate dehydrogenase. The data indicated that bdellovibrios possess periplasmic enzymes or peripheral enzymes associated with the cell wall complex. During intraperiplasmic bdellovibrio growth, periplasmic and cytoplasmic enzymes of the Escherichia coli substrate cell were not released upon formation of the spherical bdelloplast during bdellovibrio penetration. Most of the E. coli enzymes were retained within the bdelloplast until later in the growth cycle, when they became inactivated or released into the suspending buffer or both.

Quantitative Changes in the Elasticity and Adhesive Properties of Escherichia coli ZK1056 Prey Cells During Predation by Bdellovibrio bacteriovorus 109J

“…Notably, we utilize a biofilm-forming E. coli prey strain that adheres strongly and naturally to a glass surface, allowing us to make AFM measurements on native prey cells in fluid without chemically altering the bacteria. Traditional biochemical techniques have shown that bdellovibrios extensively modify the prey cell wall and cytoplasmic membrane during their “growth phase” inside of their prey, but little is known about the physical changes that result from these biochemical processes. ,,,– Here we use AFM imaging and force measurements to demonstrate that the Bdellovibrio -induced biochemical modifications cause major changes in the elasticity and adhesive properties of E. coli prey cells.…”

Investigations into the Life Cycle of the Bacterial Predator Bdellovibrio bacteriovorus 109J at an Interface by Atomic Force Microscopy

“…This process of modification and invasion changes the shape and other characteristics of the invaded cell, so that it ''rounds up'' and swells (Tudor et al, 1990). The bdellovibrio also modifies the prey's inner (cytoplasmic) membrane so that degradative enzymes and degraded cellular material can be transferred between the prey's cytoplasm and the predator (Cover et al, 1984;Odelson et al, 1982;Pritchard et al, 1975;Rittenberg and Langley, 1975;Saier, 1994).…”