[Use of disc electrophoresis in polyacrylamide gel method for the separation of soluble proteins of vibrios]

The authors present the results of a comparative study of the protein spectra of 80 strains of various vibrios. Proteinograms were elaborated by the method of disc-electrophoresis in polyacrylamide gel for each strain and species. There were revealed 25 protein peaks with definite mobility coefficients. The number of peaks and their areas varied in different species. The qualitative and the quantitative differences between the vibrio species were established. Results of investigations demonstrated a possibliity of using the protein spectra for the differentiation of microorganisms.

Vibrio parahaemolyticus gastroenteritis during, the El Tor cholera epidemic in Togo (West Africa)

In the course of the El Tor cholera epidemic in Togo (West Africa), Vibrio parahaemolyticus was identified as the causative agent of a cholera-like gastroenteritis. From September 1971 to March 1973 81 cases were confirmed bacteriologically. Seventy patients developed cholera-like symptoms and at first were wrongly diagnosed as cholera cases; 6 other patients were simultaneoulsy infected with El Tor vibrios and V. parachaemolyticus. There was a markedly higher incidence in males than in females. Only sporadic cases occurred, and outbreaks and secondary cases have not been observed. It is suggested that V. parahaemolyticus might be an important agent of acute gastroenteritis on the coast of West Africa.

Isolation and purification of prodigiosin from Vibrio psychroerythrus

The red pigment of Vibrio psychroerythrus (formerly marine psychrophile NRC 1004) was identified as prodigiosin by comparison of its mass spectrum, absorption spectrum in the visible range, and chromatographic behavior with prodigiosin isolated from Serratia marcescens. The properties of the V. psychroerythrus pigment were clearly distinguishable from five other prodigiosin-like compounds isolated from three different microorganisms.

Immunochemical studies on lipopolysaccharide from agglutinable and non-agglutinable vibrios

Lipopolysaccharide (LPS) prepared from Vibrio cholerae and a non-agglutinable (NAG; not agglutinable with O-group I serum according to Gardner and Venkatraman [13]) vibrio strain, isolated from a patient with cholera-like clinical symptoms, have been compared with respect to their chemical composition and immunological behavior. In addition to a significant difference in the chemical composition between the two lipopolysaccharides, the LPS from V. cholerae, unlike that from the NAG vibrio, requires prior treatment with alkali for it to be an effective antigen in the indirect hemagglutination test with sheep cells. It has been suggested that the alkali acts by removing excess O-acetyl group from LPS of agglutinable vibrios. LPS from the NAG vibrio consistently showed a lower antibody response in rabbits in terms of agglutinin and vibriocidal titer. Also, the class of agglutinin antibody elicited by LPS of the NAG vibrio was predominantly immunoglobin M, and that from V. cholerae was immunoglobulin G under comparable conditions.

Lipopolysaccharide and proteins of the cell envelope of Vibrio marinus, a marine bacterium

Lipopolysaccharides isolated from the marine bacterium Vibrio marinus strain PS-207 were found to be similar to the lipopolysaccharides of R mutants of enteric organisms, with respect to extraction characteristics, percentage of lipid A (61%), and sugars of the polysaccharide side chain (glucose and heptose). A high ratio (2:1) of phosphate to amino sugar was found in the lipid A. Hydroxy fatty acids constituted only 14% of the total fatty acids of the lipid A fraction, whereas branched and straight-chain fatty acids were present in greater abundance. The major envelope proteins of V. marinus strain PS-207 fell into three molecular weight classes determined by SDS gel electrophoresis. Numerous protein species were observed in urea – acetic polyacrylamide gel electrophoresis preparations.

Extractable lipids of gram-negative marine bacteria: phospholipid composition

Phospholipid compositions of 20 strains of marine and estuarine bacteria were determined. Results showed that phospholipids of marine bacteria differed very little from those of nonmarine organisms with phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol being the predominant phospholipids in all strains examined. Lyso-phosphatidylethanolamine occurred in significant quantities among a number of the marine bacteria, and two of the isolates contained significant quantities of poly-beta-hydroxybutyrate. Effects of age and growth temperature on the phospholipid composition were also investigated. It is suggested that phylogenetic relationships among bacteria may be correlated with phospholipid composition.

Isolation and characterization of the fertility factor P of Vibrio cholerae

Vibrio cholerae strains with the transmissible fertility factor P contained a supercoiled circular deoxyribonucleic acid (DNA) component amounting to between 2 and 6% of the total DNA obtained from the cells. Such a component was not observed in V. cholerae strains lacking the fertility factor. This supercoiled circular DNA was isolated from P(+) cells, and the molecular weight was determined by sedimentation velocity experiments and electron microscopy to be approximately 80 million daltons. These supercoiled circular DNA molecules, which have a guanine plus cytosine (G + C) composition of 42%, were concluded to be the extrachromosomal P factor. It was calculated that there is approximately one copy of the P factor per chromosome. A small amount of supercoiled circular DNA was occasionally isolated from the P(-) strains of V. cholerae. The function of this component, which has a molecular weight of 40 million daltons, is not known. The molecules found in the P(-) strains were readily distinguished from the P(+) circular molecules by their smaller molecular weight and different G + C composition.

Studies of the cell envelope of Vibrio parahaemolyticus

Components of the cell envelope of Vibrio parahaemolyticus were investigated. Vibrio parahaemolyticus is an estuarine microorganism associated with diseases of marine and estuarine animals and seafood-borne enteritis in man. Purified lipopolysaccharide (LPS), isolated using a 45% phenol extraction procedure, was found to contain lipid A fraction to 27% of the LPS by weight. In the lipid A fraction, glucosamine was the only amino sugar to be present and a high molar ratio of phosphate to amino sugar (2.5:1) was noted. Two hydroxy fatty acids, hydroxydodecanoic and hydroxymyristic, were identified among the fatty acids by gas–liquid chromatography. A role of the lipopolysaccharides in the salt requirement of marine bacteria is suggested.

Isolation of protective somatic antigen from Vibrio cholerae (Ogawa) ribosomal preparations

Ribosomal preparations from Vibrio cholerae Ogawa and Inaba are protective immunogens for mice challenged with either serotype. Column chromatography of ribosomal fractions separated protective antigen from the ribosomes. The antigen is a heterogeneous colloid which contains protein, lipid, and carbohydrate in the ratio 3:1:1. Amino acid composition is that of a slightly acidic protein with no unusual complement of amino acids. The lipid component consists of several longchain fatty acids and of phosphatidyl ethanolamine. The major sugars identified were glucose and galactose. The colloid can be dissolved by treatment with chelating agents and sodium dodecyl sulfate. Purification of the solubilized material or of the colloid was unsuccessful.

Vibrio psychroerythrus sp. n.: classification of the psychrophilic marine bacterium, NRC 1004

A red-pigmented organism, formerly known as marine psychrophile NRC 1004, has been classified as Vibrio psychroerythrus sp. n. Classification was mainly based on morphology, the ability of the organism to oxidize and ferment glucose, its sensitivity to vibriostat 0/129, and its deoxyribonucleic acid base composition of 40.0 moles% guanine plus cytosine, determined by thermal denaturation. The organism gave positive reactions for catalase, oxidase, and starch hydrolysis and produced acid from maltose and dextrin but not from arabinose. It was indole- and citrate-negative and reduced nitrate to nitrite without producing gas.

Crystalline cholera toxin and toxoid

The exo-enterotoxin of Vibrio cholerae has been obtained in crystalline form. A solution of the crystalline protein was equal in potency to the parent pure toxin in both choleragenicity and skin reactivity. Crystals of the natural toxoid, choleragenoid, resemble those of the toxin in appearance. A solution of crystalline choleragenoid was equivalent to the parent preparation in the flocculation test.

Deoxyribonucleic acid relationships among marine vibrios

The deoxyribonucleic acid (DNA) relationships of 80 strains identified either as Vibrio parahaemolyticus, V. alginolyticus, and V. anguillarum, or as allied marine vibrios were delineated by DNA-DNA competition experiments as well as by measuring the thermal stabilities of the DNA-DNA duplexes formed in direct binding studies. The tested strains included isolates from Japan, Europe, and the United States. The V. parahaemolyticus and V. alginolyticus groups showed an average of 67% homology to one another and 30% to strains of V. anguillarum. Significantly, a number of the isolates from the Pacific Northwest which had been previously identified as V. parahaemolyticus based on morphological, biochemical, and serological evidence were shown either to be strains of V. anguillarum or to belong to as yet unnamed groups. Most strains isolated from diseased salmon in the Pacific Northwest proved to be virtually identical with V. anguillarum type C by DNA homology experiments, thereby differentiating them from similar strains isolated from diseased herring and occasionally from salmon. The latter Pacific Northwest isolates fell into two distinct genotypic groups. A plot of the per cent homology by competition versus the difference in the thermal stabilities of heterologous and homologous duplexes (DeltaT(m,e)) between the same DNA species shows a linear decline in homology of 4.25% per degree of DeltaT(m,e). The use of this relationship for estimating the percentage of the mispaired bases distinguishing DNA preparations directly from competition experiments is discussed.

Polyphasic taxonomy of the genus Vibrio: polynucleotide sequence relationships among selected Vibrio species

Polynucleotide relationships among selected Vibrio species were examined by means of deoxyribonucleic acid (DNA) reassociation reactions and chromatography on hydroxyapatite. Relative levels of intraspecific DNA duplex formation (V. cholerae-V. cholerae and V. parahaemolyticus-V. parahaemolyticus) were found to be high at 60 C (>80%), and only minimally reduced at 75 C. Interspecific DNA duplexes between V. cholerae DNA and that of the non-cholera vibrios also exhibited high relative levels of formation at 60 C (>80%) and, with one exception, were only slightly reduced at 75 C. The thermal stability of these duplexes formed at 60 or 75 C was virtually identical to that of homologous V. cholerae DNA duplexes. The degree of reassociation and the thermal stability of V. cholerae-non-cholera vibrio DNA duplexes suggests relatively little evolutionary divergence in these organisms. In all other interspecific DNA reassociation reactions, only low levels of DNA duplex formation were noted at 60 C (<25%), and these were drastically reduced (>50%) at 75 C. The degree of nucleotide sequence divergence indicated by these reactions suggests that these Vibrio species are not significantly related to V. cholerae or V. parahaemolyticus. Reassociation reactions between V. cholerae DNA and the DNA of V. parahaemolyticus indicated these species were not significantly related to each other.

In vitro and in vivo studies of streptomycin-dependent cholera vibrios

Streptomycin-dependent cholera vibrio strains were derived from Inaba, Ogawa, and NAG vibrios by the method of Mel. These phenotypes grew more slowly and attacked fermentable substances after a longer period of time than the streptomycin-sensitive parent strains. Rabbits injected with streptomycin-sensitive strains and their streptomycin-dependent forms showed homologous agglutinin production. Patas monkeys fed with 10(9) streptomycin-dependent strains shed them for 1 to 2 days without ill effect, whereas the same number of streptomycin-independent organisms caused disease. The possibility of the application of multiple doses of streptomycin-dependent organisms in oral immunization against cholera was considered.

Chemical constituents and hydrogenase binding in cell envelopes of Vibrio succinogenes

The particulate hydrogenase of Vibrio succinogenes is solubilized during treatment of cell envelopes at pH 11.0. Alkali-solubilized enzyme requires sulfhydryl compounds for activity. At neutral pH, soluble enzyme is reincorporated into alkalitreated cell envelopes and no longer requires an additional activator. In the present study, cell envelopes prepared by lysing cells with ethylenediaminetetraacetic acid plus lysozyme (EDTA-lysozyme) were used to determine the chemical composition of cell envelopes and derived pH 11.0 soluble and insoluble fractions and to investigate some properties of the binding and activation of alkali-solubilized hydrogenase. Lysis with EDTA-lysozyme resulted in the formation of spheroplast ghosts. The derived cell envelopes contained 61% protein, 3% ash, 23% lipid, and 1% phosphorus. The alkali-treated cell envelopes contained 50% protein, 2% ash, 24% lipid, and 1% phosphorus. The ash from cell envelopes and alkali-treated cell envelopes was rich in iron and phosphorus and also contained calcium, copper, magnesium, sodium, and zinc. Virtually all of the weight of the ashed samples was accounted for by the oxides of these metals. Since the reconstitution of particulate hydrogenase was achieved with pH 11.0 supernatant solution and precipitate, intact mucopeptide is not essential for hydrogenase binding. Release of hydrogenase during EDTA-lysozyme lysis was found to depend upon an apparent structural change which occurs in the membranes during extended storage at -20 C.