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At least 19 recordsLinked to original sources
PubMed2000

A proposal for the reclassification of Bdellovibrio stolpii and Bdellovibrio starrii into a new genus, Bacteriovorax gen. nov. as Bacteriovorax stolpii comb. nov. and Bacteriovorax starrii comb. nov., respectively.

Bdellovibrios are unique bacteria with the ability to prey upon a wide variety of susceptible Gram-negative bacteria. Micro-organisms exhibiting this trait have been included in the genus Bdellovibrio despite their isolation from diverse habitats and relatively unstudied taxonomic relatedness. In this study, 16S rDNA sequences were compared from known terrestrial Bdellovibrio species, Bdellovibrio bacteriovorus 100T, Bdellovibrio stolpii Uki2T and Bdellovibrio starrii A3.12T in order to study their phylogenetic relationship. The two sequences from B. stolpii Uki2T and B. starrii A3.12T were 90.0% similar to each other but exhibited only 81.7% and 81.2% similarity, respectively to B. bacteriovorus 100T. Phylogenetic analysis indicated that B. bacteriovorus 100T clustered in a separate clade from B. starrii A3.12T and B. stolpii Uki2T, demonstrating only a distant relationship between B. bacteriovorus 100T and the other two recognized type species. DNA-DNA hybridization experiments also demonstrated <4% hybridization between these three species. On the basis of the results obtained from the phylogenetic analysis and DNA-DNA hybridization studies, it is proposed that B. stolpii Uki2T and B. starrii A3.12T should be transferred to a new genus, Bacteriovorax gen. nov. as Bacteriovorax stolpii comb. nov. and Bacteriovorax starrii comb. nov., respectively. It is also proposed that the type species for the new genus Bacteriovorax should be Bacteriovorax stolpii comb. nov.

Base Composition↗
PubMed1982

Periplasmic enzymes in Bdellovibrio bacteriovorus and Bdellovibrio stolpii.

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 enzymes 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.

5'-Nucleotidase↗
PubMed1968

Interacton of Bdellovibrio bacteriovorus and host bacteria. I. Kinetic studies of attachment and invasion of Escherichia coli B by Bdellovibrio bacteriovorus.

Quantitative methods were developed for the study of the early stages in the interaction of Bdellovibrio bacteriovorus and host bacteria. Attachment measurements were based on the differential filtration of host and parasite. Invasion was measured by estimation of radioactively labeled Bdellovibrio cells remaining attached to the host cells after mechanical agitation. The kinetics of attachment and the final number of Bdellovibrio cells attached were dependent on the multiplicity of the parasite, the composition and pH of the medium, and the incubation temperature. Inhibitors of Bdellovibrio motility, including chelating agents, NaN(3), and low pH, all inhibited attachment, as did anaerobiosis. Ultraviolet-killed host cells retained their competence for attachment of Bdellovibrio cells, whereas heat-killed cells lost it. Invasion was selectively inhibited by inhibitors of protein synthesis, such as streptomycin, puromycin, and chloramphenicol. These antibiotics had no effect on attachment.

Azides↗
PubMed1969

Interaction of Bdellovibrio bacteriovorus and host bacteria. II. Intracellular growth and development of Bdellovibrio bacteriovorus in liquid cultures.

The intracellular life cycle of Bdellovibrio bacteriovorus 109 growing on Escherichia coli in a dilute nutrient medium exhibits a period of constant infective titer while the parasite grows and elongates inside the host cell. This period is terminated after 2 to 4 hr, and the number of the plaque-forming units in the culture rises rapidly to as much as six times the initial titer. The growth pattern of Bdellovibrio is similar with actively growing or resting host cells, or with host cells killed by ultraviolet irradiation or by heating at 70 C. The yield of B. bacteriovorus strain 109 in two-membered cultures with E. coli B depends on the host concentration and may reach 7.5 x 10(10) cells per ml. Penicillin, which has no effect on the attachment and penetration of Bdellovibrio, inhibits its multiplication.

Bacteria↗
PubMed1992

Acquisition of apparently intact and unmodified lipopolysaccharides from Escherichia coli by Bdellovibrio bacteriovorus.

The ability of Bdellovibrio bacteriovorus to relocalize the OmpF major outer membrane porins from its Escherichia coli prey to its own outer membranes is diminished in prey expressing smooth lipopolysaccharide (S-LPS). Since porins exist in the membrane complexed with LPS, we examined the LPS associated with relocalized porin to determine whether it had been acquired intact, mixed or replaced with Bdellovibrio LPS, or derivatized by the bdellovibrios. The relocalized trimers were found associated with the same LPS originally bound to them in the E. coli. The bulk-phase LPS from bdellovibrios grown on various chemotypes of rough prey was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine whether more than the trimer-bound LPS was acquired by the bdellovibrios. This analysis revealed bands of Bdellovibrio LPS matching the LPS chemotype of the prey. One or two other bands were identical in migration to the LPS of prey-independent mutants of B. bacteriovorus and represented bdellovibrio-synthesized LPS. The LPS of bdellovibrios grown on prey with radiolabeled lipid A showed radioactivity only in gel band positions identical with those of the prey's LPS. The amount of this prey-derived LPS was shown by enzyme-linked immunosorbent assay to reach a constant value during the purification of the bdellovibrios, and it represented approximately 25% of the total Bdellovibrio LPS. Immunoelectron microscopy confirmed the presence of prey-derived LPS on the cell surface of bdellovibrios, and no evidence could be found for bdellovibrio-induced modifications of the relocalized prey LPS.

Bacterial Outer Membrane Proteins↗
PubMed2000

Prey range characterization, ribotyping, and diversity of soil and rhizosphere Bdellovibrio spp. isolated on phytopathogenic bacteria.

Thirty new Bdellovibrio strains were isolated from an agricultural soil and from the rhizosphere of plants grown in that soil. Using a combined molecular and culture-based approach, we found that the soil bdellovibrios included subpopulations of organisms that differed from rhizosphere bdellovibrios. Thirteen soil and seven common bean rhizosphere Bdellovibrio strains were isolated when Pseudomonas corrugata was used as prey; seven and two soil strains were isolated when Erwinia carotovora subsp. carotovora and Agrobacterium tumefaciens, respectively, were used as prey; and one tomato rhizosphere strain was isolated when A. tumefaciens was used as prey. In soil and in the rhizosphere, depending on the prey cells used, the concentrations of bdellovibrios were between 3 x 10(2) to 6 x 10(3) and 2.8 x 10(2) to 2.3 x 10(4) PFU g(-1). A prey range analysis of five soil and rhizosphere Bdellovibrio isolates performed with 22 substrate species, most of which were plant-pathogenic and plant growth-enhancing bacteria, revealed unique utilization patterns and differences between closely related prey cells. An approximately 830-bp fragment of the 16S rRNA genes of all of the Bdellovibrio strains used was obtained by PCR amplification by using a Bdellovibrio-specific primer combination. Soil and common bean rhizosphere strains produced two and one restriction patterns for this PCR product, respectively. The 16S rRNA genes of three soil isolates and three root-associated isolates were sequenced. One soil isolate belonged to the Bdellovibrio stolpii-Bdellovibrio starrii clade, while all of the other isolates clustered with Bdellovibrio bacteriovorus and formed two distantly related, heterogeneous groups.

Bdellovibrio↗
PubMed1981

Incorporation of substrate cell lipid A components into the lipopolysaccharide of intraperiplasmically grown Bdellovibrio bacteriovorus.

The composition of Bdellovibrio bacteriovorus lipopolysaccharide (LPS) was determined for cells grown axenically and intraperiplasmically on Escherichia coli or Pseudomonas putida. The LPS of axenically grown bdellovibrios contained glucose and fucosamine as the only detectable neutral sugar and amino sugar, and nonadecenoic acid (19:1) as the predominant fatty acid. Additional fatty acids, heptose, ketodeoxyoctoic acid, and phosphate were also detected. LPS from bdellovibrios grown intraperiplasmically contained components characteristic of both axenically grown bdellovibrios and the substrate cells. Substrate cell-derived LPS fatty acids made up the majority of the bdellovibrio LPS fatty acids and were present in about the same proportions as in the substrate cell LPS. Glucosamine derived from E. coli LPS amounted to about one-third of the hexosamine residues in intraperiplasmically grown bdellovibrio LPS. However, galactose, characteristic of the E. coli outer core and O antigen, was not detected in the bdellovibrio LPS, suggesting that only lipid A components of the substrate cell were incorporated. Substrate cell-derived and bdellovibrio-synthesized LPS materials were conserved in the B. bacteriovorus outer membrane for at least two cycles of intraperiplasmic growth. When bdellovibrios were grown on two different substrate cells successively, lipid A components were taken up from the second while the components incorporated from the lipid A of the first were conserved in the bdellovibrio LPS. The data show that substrate cell lipid A components were incorporated into B. bacteriovorus lipid A during intraperiplasmic growth with little or no change, and that these components, fatty acids and hexosamines, comprised a substantial portion of bdellovibrio lipid A.

Bdellovibrio↗
PubMed1969

Isolation and characterization of host-independent Bdellovibrios.

A reliable method has been developed for the isolation of host-independent (H-I; i.e., "saprophytic") strains of Bdellovibrio from host-dependent (H-D; i.e., "parasitic") cultures. The technique involves growing streptomycin-resistant (Sm(r)) H-D cultures on streptomycin-susceptible (Sm(8)) host cells. A lysate containing large numbers of the Sm(r) H-D cells and some remaining Sm(8) host cells is transferred to a selection medium which contains the antibiotic. The Sm(8) host cells in the lysate are killed, and the Sm(r) H-I strains develop in broth within 3 to 6 days. By use of this method, it has been possible to isolate H-I strains from 16 different H-D Bdellovibrio strains studied. The frequency of occurrence of host independence is in the range of one H-I colony per 10(6) to 10(7) plaque-forming units of H-D bdellovibrios. The H-I cultures are nonfermentative, do not reduce nitrate, are strongly proteolytic, are oxidase-positive, and do not utilize 14 different carbon compounds as sources of energy for growth. Most H-I cultures are catalase-positive upon initial isolation from H-D lysates, but some cultures lose this enzyme upon subsequent transfers through host-free media. Most H-I bdellovibrios are pleomorphic, consisting of vibrio- to spiral-shaped cells typically measuring 0.3 to 0.4 mum in width and 1 to 10 mum in length. All H-I bdellovibrios have a cytochrome a and c component (H-I A3.12 differs from the other strains in the location of the peaks of the cytochrome spectrum). All are sensitive to oxytetracycline and (except for strain H-I A3.12) to the vibriostatic pteridine 0/129; most bdellovibrios, except for H-I A3.12, are generally uniformly resistant or susceptible to a given antibiotic. Bdellovibrio and Vibrio spp. have common cytochrome difference spectra and susceptibilities to oxytetracycline and to the vibriostatic pteridine 0/129. All H-I bdellovibrios examined produce an exocellular protease which digests heat-killed host cells. Bdellovibrios possessing predatory and bacteriolytic properties could be reselected from H-I bdellovibrio cultures growing in the presence of living host cells. Attempts to select for bacteriolytic isolates from Vibrio and Spirillum spp. were unsuccessul.

Bacteria↗
PubMed1972

Molecular heterogeneity of the Bdellovibrios: evidence of two new species.

A systematic examination of a variety of isolates of the bacterial endoparasite Bdellovibrio has revealed extensive molecular diversity. The quantity of deoxyribonucleic acid (DNA) polynucleotide homology ranges from more than 90% among the isolates with DNA containing 50 to 51% guanine plus cytosine (GC) to undetectable levels between the 43% GC and 51% GC isolates. The two isolates with low GC-containing DNA (H-I Bdellovibrio A3.12 and UKi2) have only 16% DNA homology. H-I Bdellovibrio A3.12 and 109 have barely detectable ribosomal ribonucleic acid (rRNA) homology, whereas the homology approaches 100% among all the high GC isolates tested. Cases of high DNA/DNA and DNA/rRNA homologies are reflected in low dissimilarities of enzyme migration patterns in starch gel electrophoresis. The dissimilarities exhibited among the high GC Bdellovibrio isolates are as low as those previously reported for different Escherichia coli strains. The zymograms of H-I Bdellovibrio A3.12 and UKi2 are completely different from each other as well as from all other bdellovibrios (100% dissimilarity). Genome sizes determined for the representative isolates demonstrate three size ranges which coincide with group differences based on the above measurements. Enzyme assays reveal that all isolates possess a tricarboxylic acid cycle and most contain an alanine and glutamic dehydrogenase. We conclude that the use of bacterial endoparasitism as a defining trait has resulted in a molecularly diverse collection of isolates. It is recommended that the specific epitaph bacteriovorus be used only for the type specimen (Bdellovibrio 100 of Stolp and Starr, 1963) and for other related 50 to 51% GC isolates. The heterogeneity of the group warrants two new species. We designate Bdellovibrio A3.12 as the nomenclatural type of B. starrii sp. n. and Bdellovibrio UKi2 as the nomenclatural type of B. stolpii sp. n.

Adenine Nucleotides↗
PubMed2004

Reclassification of salt-water Bdellovibrio sp. as Bacteriovorax marinus sp. nov. and Bacteriovorax litoralis sp. nov.

Bdellovibrios are unique, predatory bacteria with an intraperiplasmic growth and multiplication phase within their prey, which consists of many Gram-negative bacteria. Until recently, all bacteria that exhibited these traits were included in the genus Bdellovibrio. However, analysis of 16S rDNA sequences and other studies have demonstrated substantial genotypic, phenotypic and ecotypic diversity among the organisms in this genus (Baer et al., 2000; Snyder et al., 2002). This has resulted in reclassification of Bdellovibrio stolpii and Bdellovibrio starrii into the newly constructed genus Bacteriovorax (Baer et al., 2000). In this study, examination of marine isolates of Bdellovibrio (designated SJT, AQ and JS5T) has revealed them to be related more closely to the newly designated genus Bacteriovorax. Phylogenetic analysis of 16S rRNA gene sequences revealed that marine isolates SJT, AQ and JS5T clustered in a separate clade from Bdellovibrio bacteriovorus 100T as part of the clade that contains Bacteriovorax spp., indicating a much closer taxonomic relationship to the latter. DNA-DNA hybridization experiments also demonstrated <5 % similarity between Bdellovibrio bacteriovorus 100T and the marine isolates. Distinct differences between the salt-water group and Bdellovibrio spp. were also observed by determination of DNA G+C content, salinity growth testing and antibiotic sensitivity analysis. On the basis of the results from the studies described above, it is proposed that marine isolates SJT (=ATCC BAA-682T=DSM 15412T) and JS5T (=ATCC BAA-684T=DSM 15409T) should be classified within the genus Bacteriovorax as the type strains of Bacteriovorax marinus sp. nov. and Bacteriovorax litoralis sp. nov., respectively.

Bacterial Typing Techniques↗
PubMed1978

Metabolism of RNA-ribose by Bdellovibrio bacteriovorus during intraperiplasmic growth on Escherichia coli.

During intraperiplasmic growth of Bdellovibrio bacteriovorus 109J on Escherichia coli some 30 to 60% of the initial E. coli RNA-ribose disappeared as cell-associated orcinol-positive material. The levels of RNA-ribose in the suspending buffer after growth together with the RNA-ribose used for bdellovibrio DNA synthesis accounted for 50% or less of the missing RNA-ribose. With intraperiplasmic growth in the presence of added U-14C-labeled CMP, GMP, or UMP, radioactivity was found both in the respired CO2 and incorporated into the bdellovibrio cell components. The addition of exogenous unlabeled ribonucleotides markedly reduced the amounts of both the 14CO2 and 14C incorporated into the progeny bdellovibrios. During intraperiplasmic growth of B. bacteriovorus on [U-14C]ribose-labeled E. coli BJ565, ca. 74% and ca. 19% of the initial 14C was incorporated into the progeny bdellovibrios and respired CO2, respectively. Under similar growth conditions, the addition of glutamate substantially reduced only the 14CO2; however, added ribonucleotides reduced both the 14CO2 and the 14C incorporated into the progeny bdellovibrios. No similar effects were found with added ribose-5-phosphate. The distribution of 14C in the major cell components was similar in progeny bdellovibrios whether obtained from growth on [U-14C]ribose-labeled E. coli BJ565 or from E. coli plus added U-14C-labeled ribonucleotides. After intraperiplasmic growth of B. bacteriovorus on [5,6-3H-]uracil-[U-14C]ribose-labeled E. coli BJ565 (normal or heat treated), the whole-cell 14C/3H ratio of the progeny bdellovibrios was some 50% greater and reflected the higher 14C/3H ratios found in the cell fractions. B. bacteriovorus and E. coli cell extracts both contained 5'-nucleotidase, uridine phosphorylase, purine phosphorylase, deoxyribose-5-phosphate aldolase, transketolase, thymidine phosphorylase, phosphodeoxyribomutase, and transaldolase enzyme activities. The latter three enzyme activities were either absent or very low in cell extracts prepared from heat-treated E. coli cells. It is concluded that during intraperiplasmic growth B. bacteriovorus degrades some 20 to 40% of the ribonucleotides derived from the initial E. coli RNA into the base and ribose-1-phosphate moieties. The ribose-1-phosphate is further metabolized by B. bacteriovorus both for energy production and for biosynthesis, of non-nucleic acid cell material. In addition, the data indicate that during intraperiplasmic growth B. bacteriovorus can metabolize ribose only if this compound is available to it as the ribonucleoside monophosphate.

Bdellovibrio↗
PubMed1988

Metabolism of periplasmic membrane-derived oligosaccharides by the predatory bacterium Bdellovibrio bacteriovorus 109J.

Membrane-derived oligosaccharides (MDO), a class of osmotically active carbohydrates, are the major organic solutes present in the periplasm of Escherichia coli and many other gram-negative bacteria when cells are grown in a medium of low osmolarity. Analyses of growing cells of Bdellovibrio bacteriovorus, a gram-negative predator of other bacteria, have confirmed that they also synthesize a characteristic MDO-like class of oligosaccharides. The natural growth environment of bdellovibrios is the periplasm of other gram-negative bacteria. Because of this location, prey cell MDO constitute a potential source of organic nutrients for growing bdellovibrios. Using cells of E. coli whose MDO were 3H labeled, we examined the extent to which B. bacteriovorus 109J metabolizes these prey cell components. Interestingly, there was neither significant degradation nor incorporation of prey cell MDO by bdellovibrios during the course of their intracellular growth. In fact, bdellovibrios had little capability either to degrade extracellular MDO that was made available to them or to transport glucose, the major monomeric constituent of prey cell MDO. Instead, periplasmic MDO were irreversibly lost to the extracellular environment during the period of bdellovibrio attack and penetration. Thus, although prey cell periplasmic proteins are retained, other important periplasmic components are released early in the bdellovibrio growth cycle. The loss of these MDO may aid in the destabilization of the prey cell plasma membrane, increasing the availability of cytoplasmic constituents to the periplasmic bdellovibrio.

Bdellovibrio↗
PubMed1984

Distribution of bdellovibrios in the water column of an estuary.

The distribution of bdellovibrios in the water column of the Miles River has been studied. Water samples were collected every 4 h over a 24-h period from five depths in the water column. The samples were cultured for the recovery of bdellovibrios lytic against Vibrio parahaemolyticus. Environmental parameters, i.e., salinity, temperature, turbidity, and dissolved oxygen (DO) were measured for each sample. Bdellovibrios were observed to be uniformly distributed at all depths measured in the water columns. There were no significant differences between the number of bdellovibrios recovered at the various depths. There were significant differences between the number of bdellovibrios recovered at various sampling times. However, no basis for these significant differences could be established. No association was found between the number of bdellovibrios recovered and the environmental parameters measured. Of interest was the observation that the distribution of the aerobic bdellovibrios did not correlate with DO measurements. The results suggest that neither depth nor DO content influenced the recovery of bdellovibrios from the Miles River.

Bdellovibrio↗
PubMed1976

[Detection of bdellovibrios and bacteriophages in the seawater near the shores].

The frequency of occurrence of bdellovibrios and intestinal bacteriophages at the sites of contamination in the sea and along the sea shore and at the points remote from the sources of contamination was studied. At the contaminated sites bdellovibrios were revealed in 73.3-100% and bacteriophage in 75-83.4% of the samples. There was found to be a moderate correlative association between the bdellovibrios, bacteriophages and the coli titre. In the water of the shore region of the sea bdellovibrios were found in 15.4%, and bacteriophages in 20.9% of the samples. An attempt at a sanitary assessment of beaches by the data of bdellovibrio detection was unsuccessful. There was found no correlative association between the coli-titre and the bdellovibrios in the water of the shore area. Bdellovibrio proved to play an insignificant role in the processes of self-purification from the intestinal microbial flora of weakly and moderately contaminated sea water. Taking into consideration the high resistance in the sea water of the intestinal bacteriophages preference was given to them over the bdellovibrios as the index of the sea water contamination.

Bacteriophages↗
PubMed1990

Formation of stable bdelloplasts as a starvation-survival strategy of marine bdellovibrios.

Several wild-type isolates of marine bdellovibrios formed stable bdelloplasts when they infected gram-negative bacterial prey under certain culture conditions. Synchronous predator-prey cultures and low nutrient concentrations increased the yield of stable bdelloplasts. The bdellovibrio cells retained in the stable bdelloplasts showed a high survival capacity in nutrient-depleted saline solution (10% viable Bdellovibrio cells after 3 months at 25 degrees C), whereas Bdellovibrio attack-phase cells kept under the same starvation conditions lost viability more quickly (1% viable cells after 48 h). The addition of yeast extract to a stable bdelloplast suspension induced lysis of the bdelloplasts and release of motile infecting attack-phase Bdellovibrio cells. Other substances, such as free amino acids, protein hydrolysates, NH(4), carbohydrates, and organic amines, did not induce such a release. Stable bdelloplasts were highly hydrophobic and had a lower endogenous respiration rate than attack-phase cells. In general, stable bdelloplasts were almost as sensitive to temperature changes, desiccation, sonication, tannic acid, and Triton X-100 treatment as attack-phase cells. Electron microscopy of stable bdelloplasts did not reveal any extra cell wall layer, either in the bdelloplast envelope or in the retained Bdellovibrio cells, unlike the bdellocysts of the soil bacterium Bdellovibrio sp. strain W. We propose that formation of stable bdelloplasts is a survival strategy of marine bdellovibrios which occurs in response to nutrient- and prey-poor seawater habitats.

Journal Article↗
PubMed1997

Effects of temperature, salinity, and substrate on the colonization of surfaces in situ by aquatic bdellovibrios.

Recent studies suggest that surfaces are a more conducive habitat than the water column for the proliferation of bdellovibrios in the aquatic environment. The effect of temperature and salinity on the colonization of bdellovibrios on oyster shell, glass, and polystyrene surfaces in situ was investigated over an annual cycle. Sterile surfaces were suspended in various bodies of water for intervals ranging from 24 to 120 h. The results revealed that bdellovibrios associated with different types of surfaces over a broad temperature and salinity range. After 24 h of submersion in waters with temperatures from 9.0 to 26.7(deg)C, the ranges in log(inf10) values per square centimeter for the three surfaces were as follows: oyster shell, 2.2 to 2.5; glass, 0.3 to 2.2; and polystyrene, 0.7 to 1.6. Bdellovibrios were not recovered from surfaces submerged in water at temperatures below 8(deg)C during the 120-h experimental cycle. The number of bdellovibrios and culturable bacteria on oyster shells was significantly higher than the numbers on glass and polystyrene at all time intervals. The number of bdellovibrios was positively correlated with temperature and salinity on all surfaces. A positive correlation between the number of recoverable bacteria and temperature was observed, but the results with respect to salinity were diverse. The numbers of bdellovibrios recovered from oyster shells (up to 48 h) and water samples were significantly increased at salinities greater than 11(permil) compared to those in lower-salinity environments. The results of this study reveal that like many other bacteria in the aquatic environment, bdellovibrios prefer to associate with surfaces. This association provides the predators a rich source of prey bacteria in surface biofilms and perhaps protection in the gel-like matrix of the biofilm.

Journal Article↗
PubMed1976

Response of Neisseria gonorrhoeae to Bdellovibrio species.

Bdellovibrio species are small, highly motile bacteria that are predators upon other bacteria in nature. Bdellovibrios attach to, penetrate, replicate within, and destroy prey that share the general characteristic of gram negativity. The lipopolysaccharide moiety of the cell membrane of target microorganisms appears to contain the principal receptor site for bdellovibrio attachment. Since gonococci also contain lipopolysaccharide that is similar in many respects to that contained within gram-negative rods, studies were conducted to determine the extent of gonococcal interaction with a variety of bdellovibrio species. Despite transient attachment, penetration of gonococci by bdellovibrios never occurred. Failure of bdellovibrio parasitization was unrelated to gonococcal species, colony type, piliation, penicillin susceptibility, or virulence as influenced by passage in embryonated eggs. In experiments involving mixtures of gonococci and more typical gram-negative bacillary prey, the latter were always attacked by bdellovibrios, whereas the former were ignored. Despite evidence for similarities between gonococcal and gram-negative bacillary lipopolysaccharides, resemblances do not extend to the point where gonococci are susceptible to bdellovibrio parasitization.

Gram-Negative Aerobic Bacteria↗