Host-independent Growth of Bdellovibrio bacteriovorus in Microbial Extracts

Reiner, Albey M.; Shilo, Moshe

doi:10.1099/00221287-59-3-401

Cited by 34 publications

(31 citation statements)

References 3 publications

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“…Strikingly, a different gene-expression profile was obtained in AP cells incubated with prey extract without ghosts: bd0108 and pilA were not silenced, and groES1 and ftsZ, both strongly enhanced in the GP (40,56), were specifically induced. The other GP marker genes (pcnB, dgcB, rpoD, and rpoH) as well as the bdelloplast formation genes (bd0816 and bd3459) and merRNA responded similarly as when incubated with the ghost preparation.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies suggested that prey extracts might elicit preyindependent growth of WT B. bacteriovorus (40,41). However, we were unable to replicate these results.…”

Section: Discussionmentioning

confidence: 99%

“…Several efforts were made in the past to elicit growth of WT B. bacteriovorus with prey extract. These attempts met with varying degrees of success and could not be replicated (40,41).…”

Section: Significancementioning

confidence: 99%

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Cell-cycle progress in obligate predatory bacteria is dependent upon sequential sensing of prey recognition and prey quality cues

Rotem

Pasternak

Shimoni

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Predators feed on prey to acquire the nutrients necessary to sustain their survival, growth, and replication. In Bdellovibrio bacteriovorus, an obligate predator of Gram-negative bacteria, cell growth and replication are tied to a shift from a motile, free-living phase of search and attack to a sessile, intracellular phase of growth and replication during which a single prey cell is consumed. Engagement and sustenance of growth are achieved through the sensing of two unidentified prey-derived cues. We developed a novel ex vivo cultivation system for B. bacteriovorus composed of prey ghost cells that are recognized and invaded by the predator. By manipulating their content, we demonstrated that an early cue is located in the prey envelope and a late cue is found within the prey soluble fraction. These spatially and temporally separated cues elicit discrete and combinatory regulatory effects on gene transcription. Together, they delimit a poorly characterized transitory phase between the attack phase and the growth phase, during which the bdelloplast (the invaded prey cell) is constructed. This transitory phase constitutes a checkpoint in which the late cue presumably acts as a determinant of the prey's nutritional value before the predator commits. These regulatory adaptations to a unique bacterial lifestyle have not been reported previously.microbial ecology | bacterial physiology | bacterial cell cycle | predatory bacteria | Bdellovibrio bacteriovorus

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Section: Discussionmentioning

confidence: 99%

“…Previous studies suggested that prey extracts might elicit preyindependent growth of WT B. bacteriovorus (40,41). However, we were unable to replicate these results.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Cell-cycle progress in obligate predatory bacteria is dependent upon sequential sensing of prey recognition and prey quality cues

Rotem

Pasternak

Shimoni

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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show abstract

“…They do not, however, initiate rounds of DNA replication. Indeed, all attempts to culture wild-type Bdellovibrio isolates axenically on commercial media have failed (5,8,14,21). One possible explanation for this host dependency is that wild-type bdellovibrios might be auxotrophs that require a nutritional factor that is absent from standard complex media.…”

Section: Nature Of Bdellovibrio Host Dependencementioning

confidence: 99%

Bdellovibrio host dependence: the search for signal molecules and genes that regulate the intraperiplasmic growth cycle

Thomashow

Cotter

1992

J Bacteriol

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“…At present, little is known about this aspect of Bdellovibrio biology. Biochemical studies have demonstrated that concentrated cellular extracts from hosts and other bacteria can induce wild-type bdellovibrios to multiply on rich media (6,9,15). However, no specific growth factors or signal molecules have been identified, and the mechanism by which the extracts stimulate bdellovibrios to grow and multiply is not known (24).…”

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confidence: 99%

Identification of a Bdellovibrio bacteriovorus genetic locus, hit, associated with the host-independent phenotype

Cotter

Thomashow

1992

J Bacteriol

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Bdellovibrios invade and grow within the periplasmic space of suitable gram-negative bacteria. Wild-type bdellovibrios are obligately dependent on host cells for growth, but spontaneous host-independent (H-I) mutants that grow axenically on standard rich culture media can be isolated. Such mutants generally retain the ability to grow intraperiplasmically, although the plaques that they produce on lawns of host cells are smaller and more turbid than those produced by wild-type bdellovibrios. Here, we identify the first genetic locus associated with the H-I phenotype: hit (host interaction). We show that three individual H-I mutants suffered mutations at the hit locus and that recombination of wild-type hit sequences into the genomes of the H-I mutants greatly enhanced their plaquing ability. DNA sequence analysis localized the hit mutation in each of the H-I mutants to a 135-bp region of the genome. Mutations at hit may not fully account for the H-I phenotype, however, as recombination of wild-type hit sequences into the genomes of the H-I mutants had little effect on the axenic-growth phenotype of the mutants. Possible explanations for this result and potential roles for the hit locus are discussed.

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Host-independent Growth of Bdellovibrio bacteriovorus in Microbial Extracts

Cited by 34 publications

References 3 publications

Cell-cycle progress in obligate predatory bacteria is dependent upon sequential sensing of prey recognition and prey quality cues

Cell-cycle progress in obligate predatory bacteria is dependent upon sequential sensing of prey recognition and prey quality cues

Bdellovibrio host dependence: the search for signal molecules and genes that regulate the intraperiplasmic growth cycle

Identification of a Bdellovibrio bacteriovorus genetic locus, hit, associated with the host-independent phenotype

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