Characterization of germination and activation of Bdellovibrio bdellocysts

Abstract

A simple method of assaying germination of bdellocysts in liquid medium has been devised. Bdellocysts can be induced to genninate by any of eight L-amino acids or the monovalent cations K+ and NH4+. L-Glutamine was the best individual inducer of germination, although the resulting rate of germination was much slower than in a complex medium. The use of a defined germination medium containing L-glutame, KCl, and NH4Cl produced a faster rate of germination than did complex media. Bdellocysts germinated most rapidly at pH 8.0 and at 35°C and required aerobic conditions. Respiration ofbdeliocysts began to increase at 3 min after the addition of germinants. Germination was inhibited by respiratory-chain inhibitors and by inhibitors of macromolecular synthesis. When bdellocysts were heat shocked at sublethal temperatures for short periods, there was no effect on the rate of germination in the defined germination medium or in the complex medium. However, heat-shocked bdellocysts germinated at a much faster rate in the presence of single inducers of germination when compared to nonshocked bdeilocysts. The bdeflovibrios are predacious bacteria that are capable of growth on susceptible prey bacteria. One strain, Bdellovibrio sp. strain W (2),

Formation of Stable Bdelloplasts as a Starvation-Survival Strategy of Marine Bdellovibrios

“…Bdellovibrio sp. strain W bdellocysts can be induced to germinate by glutamine and other amino acids and by NH4' ions (18). Nevertheless, these compounds and many others do not induce activation of stable bdelloplasts from marine bdellovibrios.…”

“…This survival mechanism has not been described previously, and there are important differences between this survival mechanism and the survival mechanism of bdellocysts of Bdellovibrio sp. strain W. For example, after activation, each stable bdelloplast releases more than one progeny cell, depending on the initial size of the prey cells, whereas a germinating bdellocyst gives rise to a single attack-phase cell (18). Another difference is that stable bdelloplasts are not notably resistant to environmental factors, such as desiccation.…”

Whole-Genome Sequencing and Comparative Genome Analysis Provided Insight into the Predatory Features and Genetic Diversity of TwoBdellovibrioSpecies Isolated from Soil

“…Members of the genus Bdellovibrio are diverse with some of them exhibiting unique features that can influence their ecological adaptations. For instance, B. bacteriovorus strain W has the unique ability to develop a dormant structure called bdellocyst which can help them survive unfavorable conditions [ 4 ]. B. bacteriovorus is an obligate predatory bacterium.…”

Impact of bdellovibrio-and-like organisms (BALOs) on mixed species biofilm communities

“…This phase is characterized by Bdellovibrio cell elongation into a filamentous cell(Figure 1.2 E). During growth in the periplasm, the predator and prey cell together form a structure termed as the 'bdelloplast'[90,91]. The bdelloplast has been found to be more withstanding than the vegetative counterparts to a number of stresses, such as desiccation, high temperature, sonication, as well as attacks from other microbial predators[85].…”

“…Both of the predators formed plaques on lawns of K. pneumoniae and P. protegens Pf-5, suggesting that the isolated predators might have prey ranges that extend across multiple bacterial species. The plaques formed by 'BALOs #2' were also consistent with those formed by relatively well-studied Bdellovibrio spp., such as B.bacteriovorus HD100 and B. bacteriovorus 109J[89,91], suggesting 'BALOs #2' is closely related to the group of Bdellovibrio spp.FISH and 16S rRNA gene sequence analysis was performed to determine the phylogenetic classification and the identities of these predatory species. For the FISH They do not penetrate into the prey's inner compartments, but rather function by adhering to the prey's surface and 'sucking' the nutrients from the attached prey cell.…”