Particle agglutination assays to identify fibronectin and collagen cell surface receptors and lectins in Aeromonas and Vibrio species

A rapid particle agglutination assay (PAA) utilizing latex beads coated with connective tissue and serum proteins was evaluated for its ability to identify fibronectin, collagen (types I and IV), fibrinogen, and transferrin cell surface receptors on Vibrio and Aeromonas strains isolated from diseased fish, human infections, and the environment. Similar tests were performed to screen for cell surface lectins. Vibrio as well as Aeromonas strains were found to bind connective tissue proteins (collagen types I, II, and IV and fibronectin), serum proteins (i.e., fibrinogen), and glycoproteins (bovine submaxillary mucin, hog gastric mucin, orosomucoid, and fetuin) immobilized on the latex particles. The specificity of the agglutination reaction was studied by particle agglutination inhibition assays performed by preincubating bacterial suspensions in solutions containing either gelatin (for the various connective tissue protein PAA reagents) or sialic acid-rich glycoproteins (for the various glycoprotein PAA reagents). Expression of cell surface receptors for connective tissue proteins was found to depend on culture methods.

A trans-unsaturated fatty acid in a psychrophilic bacterium, Vibrio sp. strain ABE-1

A high level of a trans-unsaturated fatty acid was found in the phospholipids of a psychrophilic bacterium, Vibrio sp. strain ABE-1. This fatty acid was identified as 9-trans-hexadecenoic acid (C16:19t) by gas-liquid chromatography and infrared absorption spectrometry. C16:1(9)t accounted for less than 1% of the total fatty acids in cells grown at 5 degrees C and reached 12% of the total at 20 degrees C. We suggest that the increase in the level of the trans-unsaturated fatty acid is related to the high growth rate of this bacterium at elevated temperatures. Possible biological roles of the trans-unsaturated fatty acid in the adaptation of the microorganism to the ambient temperature are discussed.

Studies on the lipopolysaccharide of a virulent and an avirulent strain of Vibrio vulnificus

Vibrio vulnificus is a marine bacterium associated with both primary septicemias and wound infections in humans. The lipopolysaccharides of a virulent and an avirulent strain of Vibrio vulnificus were compared with respect to their chemical constituents and electrophoretic characteristics. 2-Keto-3-deoxyoctonic acid, a normal constituent of the lipopolysaccharide of typical Enterobacteriaceae, was not found in the lipopolysaccharide of either strain. Hexadecenoate (C16:1) was the predominant fatty acid of the lipid A moiety of the lipopolysaccharides and of the membrane phospholipids of both strains. Hydroxy fatty acids composed 44% of the total fatty acids of the lipid A of the avirulent and 40% of those in the virulent strain. In addition, odd-numbered fatty acids were detected in both lipopolysaccharides. The electrophoretic profile was similar for both strains, but demonstrated no "ladder-like" pattern characteristic of "smooth" lipopolysaccharides. The result of this study showed no significant differences between the lipopolysaccharides of the virulent and avirulent strains of Vibrio vulnificus. The possible role for lipopolysaccharide in pathogenesis of Vibrio vulnificus infections is discussed.

[Chemical properties of lipopolysaccharide (LPS) isolated from Vibrio anguillarum PT514]

Vibrio anguillarum, one of the causative agents of fish vibriosis, is serologically and biochemically divided into three groups (A, B and C). The chemical composition and molecular architecture of lipopolysaccharide (LPS) isolated from V. anguillarum PT 514, which belongs to serogroup B, were investigated. The LPS contained glucose (Glc), fructose (Fru), L-glycero-D-mannoheptose (L-D Hep), glucosamine (GlcN) and 4-amino-4,6-dideoxyglucose as sugar constituents in molar ratios of 8.9:0.7:3.0:1.1:1.6. Sephadex G-50 gel-chromatography of a degraded polysaccharide fraction separated from the LPS by 5% acetic acid hydrolysis suggested that the O-specific polysaccharide region consists of, in average, as much as 29 moles of Glc per 3 moles of L-D Hep, while the core polysaccharide contains at least Glc, L-D Hep and GlcN in molar ratios of 3.2 : 3.0 : 0.2. Fru and 4-amino-4,6-dideoxyglucose components were released from LPS on weak-acid hydrolysis, indicating that PT 514 LPS is distinguishable from those of Vibrio anguillarum belonging to the other serogroups. 2-Keto-3-deoxyoctonate (KDO), a common sugar constituent of gram-negative bacterial LPS, was not detected by Weissbach's color reaction under the conventional hydrolysis condition, but O-phosphoryl KDO was found in the strong-acid hydrolysate (4 M HCl, 100 C, 45 min). This substance was identical, at least in high-voltage paper electrophoresis, to 5-O-phosphoryl KDO.(ABSTRACT TRUNCATED AT 250 WORDS)

A common cytolytic region in myotoxins, hemolysins, cardiotoxins and antibacterial peptides

Several proteins and polypeptides of reptilian, amphibian, insect, and microbial origin share a common cytolytic property. However, these cytolysins fulfill different objectives. They provide offensive armament in the case of toxins, but defensive systems in the case of antibacterial peptides. The sequences of several nonenzymatic cytolysins and their analogues were compared to identify the structural requirements for cytolytic activity. These cytolysins, although isolated from phylogenetically unrelated organisms, possess the common sequence features of a cationic site flanked by a hydrophobic surface. The presence of such a region apparently confers the cytolytic activity of various cytolysins. The concept of a cytolytic region is strongly supported by the existence of several natural and synthetic analogues of cytolysins and by chemical modification studies of these cytolysins. This prediction provides a new focus for cytolysin research. The understanding of this structure-function relationship should facilitate the design, synthesis, and development of better antibacterial and anticancer peptides.

Homogeneity of a hemolysin(Vh-rTDH) produced by clinical and environmental isolates of Vibrio hollisae

The characteristics of Vh-rTDH, a hemolysin similar to Vp-TDH of Vibrio parahaemolyticus produced by clinical and environmental isolates of Vibrio hollisae, were comparatively studied. All 7 strains of V. hollisae tested were found to produce indistinguishable Vh-rTDH when they were examined by heat-stability test, Western blotting analysis and conventional polyacrylamide slab gel electrophoresis.

A comparative study of the sugar composition of lipopolysaccharides isolated from Vibrio cholerae, 'Vibrio albensis' and Vibrio metschnikovii

A comparative study was made of the quantitative sugar composition of lipopolysaccharides (LPS) isolated from Vibrio cholerae (O1 and non O1 groups), 'V. albensis', 'V. proteus' and V. metschnikovii. The amino sugars 4-amino-4,6-dideoxy-D-mannose (perosamine) and 2-amino-2,6-dideoxy-D-glucose (quinovosamine) were present exclusively in LPS isolated from S-form O1 group of V. cholerae regardless of serotype (i.e. Ogawa or Inaba) and biotype (i.e. classical or eltor). Classical O1 group V. cholerae was distinguishable from eltor O1 group V. cholerae on the basis of the fructose content of the LPS: greater than 3% and less than or equal to 1%, respectively. Distinct differences in the sugar composition of LPS were observed between V. cholerae and 'V. albensis', 'V. proteus' and V. metschnikovii.

Purification and characterization of Vibrio metschnikovii cytolysin

An extracellular cytolysin produced by Vibrio metschnikovii was purified by acid precipitation, phenyl-Sepharose CL-4B chromatography, and rechromatography on a phenyl-Sepharose CL-4B column and high-performance liquid chromatography on a Mono Q (anion-exchange) column. The purified cytolysin had a molecular weight of 50,000 and an isoelectric point of 5.1. It was inactivated by heating at 60 degrees C for 5 min and was inhibited by Zn2+, Cu2+, and high concentrations of cholesterol. Lysis of calf erythrocytes by cytolysin was temperature dependent and occurred only above 18 degrees C. Moreover, no lysis was observed at high concentrations of erythrocytes, suggesting that the cytolysin lyses erythrocytes by a multihit mechanism. This cytolysin had no immunological cross-reactivities with hemolysins from other Vibrio species tested, indicating that it is a new cytolysin. V. metschnikovii cytolysin lysed erythrocytes from several animal species (calf, rabbit, guinea pig, mouse, human, sheep, chicken, and horse) and cultured cells (Vero and Chinese hamster ovary), caused fluid accumulation in the intestines of infant mice, and increased vascular permeability in rabbit skin.

Purification of the yellow fluorescent protein from Vibrio fischeri and identity of the flavin chromophore

A low molecular weight protein (approximately 25,000 D) exhibiting a yellow fluorescence emission peaking at approximately 540 nm was isolated from Vibrio fischeri (strain Y-1) and purified to apparent homogeneity. FMN is the chromophore, but it exhibits marked red shifts in both the absorption (lambda max = 380, 460 nm) and the fluorescence emission. When added to purified luciferase from the same strain, which itself catalyzes an emission of blue-green light (lambda max approximately 495 nm), this protein induces a bright yellow luminescence (lambda max approximately 540 nm); this corresponds to the emission of the Y-1 strain in vivo. This yellow bioluminescence emission is thus ascribed to the interaction of these two proteins, and to the excitation of the singlet FMN bound to this fluorescent protein.

Fluid accumulation in infant mice caused by Vibrio hollisae and its extracellular enterotoxin

Vibrio hollisae, a halophilic bacterium isolated from patients with diarrhea, was examined for virulence factor production. Intragastric administration of 2 X 10(7) CFU per mouse elicited fluid accumulation which peaked at ca. 6 h postchallenge in infant mice. An enterotoxin which elongated Chinese hamster ovary (CHO) cells was detected in extracts of infected-mouse intestines and in culture fluids from various growth media. The yield of the enterotoxin was maximal beginning at the onset of the stationary phase of growth in heart infusion broth supplemented with 0.5% NaCl. A concentrated preparation obtained by ammonium sulfate precipitation of culture supernatant fluids induced intestinal fluid accumulation which peaked at 2 h postchallenge in infant mice. The abilities of the enterotoxin preparation to elongate CHO cells and to elicit fluid accumulation in infant mice were inseparable by gel filtration, isoelectric focusing, and hydrophobic interaction chromatography. The enterotoxin has a molecular weight of ca. 33,000 by gel filtration and an isoelectric point of ca. 4 and is sensitive to heat.

Structural elucidation of the O-specific polysaccharide of the phenol-phase soluble lipopolysaccharide of Vibrio anguillarum

The structure of the O-specific polysaccharide of the phenol-soluble cellular lipopolysaccharide of Vibrio anguillarum has been investigated. The studies involved the use of methylation analysis, partial hydrolysis with 48% hydrogen fluoride, Smith degradation, oxidation with chromium trioxide, and comprehensive proton and carbon-13 nuclear magnetic resonance studies, in which one- and two-dimensional experiments were carried out. As a result of these studies it is proposed that the O-specific polysaccharide of Vibrio anguillarum is composed of a regular heteropolymer, i.e., a main chain of (1----4)-linked 3-acetamido-3,6-dideoxy-beta-L-glucose residues alternately substituted through O-2 with side chain residues of 2-acetamido-2,6-dideoxy-alpha-D-glucose, which seem to be substituted through either O-3 or O-4 with propionyl groups (R), as in the following structure. (Formula: see text)

[Similarity of Vibrio alginolyticus, V. cholerae and other Vibrio species with respect to the structure of their flagellar apparatus and ribosomal 5S-RNA]

Electron microscopic analysis of basal bodies of the flagella Vibrio alginolyticus revealed a structure composed of four discs. The diameters of two discs localized in the cytoplasmic membrane appeared to be twice as little as those of the other two discs. In this respect the basal body of V. alginolyticus resembles that of V. cholerae. The 5S sequence of ribosomal RNA from V. alginolyticus appeared to be similar to those of V. cholerae, V. harveyi and some other vibrios. Comparison of 5S-RNA sequence culminated in a dendrogram of evolutionary relationships of various bacterial species, suggesting that V. alginolyticus is a typical representative of the Vibrionacea family. The data obtained are discussed in terms of the role of Na+ energy metabolism in living cells.

Characterization of anguibactin, a novel siderophore from Vibrio anguillarum 775(pJM1)

Anguibactin, a siderophore produced by cells of Vibrio anguillarum 775 harboring the pJM1 plasmid, has now been isolated from the supernatants of iron-deficient cultures. This iron-reactive material was purified by adsorption onto an XAD-7 resin and subsequent gel filtration on a Sephadex LH-20 column. The resulting neutral compound produced an ion at m/z 348 in mass spectrometry and contained one sulfur, four oxygen, and four nitrogen atoms as determined by elemental analysis. Its strong UV absorbance and blue fluorescence were suggestive of a phenolic moiety. In colorimetric reactions anguibactin behaved like a catechol. The catechol assignment was supported by the appearance of a new absorption band at 510 nm in the ferric complex and by the appearance of peaks at 1,367, 1,447, 1,469, and 1,538 cm-1 in the resonance Raman spectrum. In addition, the infrared spectrum gave evidence of a secondary amide function, but no free carboxylic acid or hydroxamic acid groups were observed. A third iron-ligating group was suggested by the liberation of three protons during iron binding; mass spectrometry of the resulting material yielded a molecular ion characteristic of a 1:1 complex of ferric anguibactin. The purified anguibactin exhibited specific growth-promoting activity under iron-limiting conditions for a siderophore-deficient mutant of V. anguillarum 775(pJM1). A novel structure for anguibactin was indicated by the failure of a large number of known siderophores and synthetic chelators to yield a similar type of specific cross-feeding in the V. anguillarum bioassay.

Differential scanning calorimetry of bacteria

Thermograms obtained by differential scanning calorimetry of a range of bacteria of different heat resistances were compared. Equations were derived to calculate the rate at which the numbers of viable organisms in a calorimeter decline as the temperature is raised at a constant rate. Vegetative bacteria scanned at 10 degrees C min-1 showed multi-peaked thermograms with four major peaks (denoted m, n, p and q) occurring in the regions 68-73, 77-84, 89-99 and 105-110 degrees C respectively. Exceptions were that peak m (the largest peak) occurred at 79-82 degrees C in Bacillus stearothermophilus and an additional peak, r, was detected in Escherichia coli at 119 degrees C. At temperatures below the main peak m there were major differences in thermograms between species. There was a direct relationship between the onset of thermal denaturation and the thermoresistance of different organisms. Heat-sensitive organisms displayed thermogram features which were absent in the more heat-resistant types. When samples were cooled to 5 degrees C and re-heated, a small endothermic peak, pr, was observed at the same temperature as p. Peaks p and pr were identified as the melting endotherms of DNA. In all vegetative organisms examined, maximum death rates, computed from published D and z values, occurred at temperatures above the onset of thermal denaturation, i.e. cell death and irreversible denaturation of cell components occurred within the same temperature range.

Characterization of extracellular substance of Vibrio anguillarum toxic for rainbow trout and mice

An extracellular toxic substance was separated from the cell-free culture filtrate of Vibrio anguillarum (strain NCMB571). Two fractions (GI and GII + III) obtained by Sephadex G-200 chromatography following DEAE-cellulose chromatography were lethal to rainbow trout and mice. Material separated from the GI fraction by Sepharose 4B affinity chromatography (GI-A fraction) was lethal to these animals. By sodium dodecylsulfate polyacrylamide gel electrophoresis, the GI and GI-A fractions were found to be composed of components with molecular weights of 44K and 34K, and 44K, respectively. The 44K protein band was associated with carbohydrate. Peripheral vascular disorder was observed in fish and mice that died after inoculation with GI or GI-A fraction. The toxic substance was sensitive to potassium periodate but was resistant to trypsin and acetone. Heat inactivation of the toxic substance was almost complete at 100 C for 20 min and complete at 121 C for 20 min. The toxic activity was not associated with hemolytic or proteolytic activity. Homologous antitoxin completely neutralized the toxic activity.

Isolation and characterization of a cyclic AMP receptor protein from luminous Vibrio harveyi cells

A cAMP receptor protein (CRP) species was purified from the luminous Vibrio harveyi cells to apparent homogeneity. This protein had a dimeric structure with a molecular weight of 23,000 per subunit. Among all eight nucleotides tested, only cAMP (Kd = 3 to 4 microM at 0 degrees C and 52 microM at 23 degrees C) and cGMP (Kd = 6 to 10 microM at 0 degrees C and 67 microM at 23 degrees C) bound to this protein. Its binding to poly(dI-dC), poly(dA-dT), and DNA fragments isolated from V. harveyi cells were all significantly enhanced by the addition of cAMP. Based on patterns of limited proteolysis by trypsin, this CRP assumes different conformations in the absence and presence of cAMP. Also consistent with this conclusion is the finding that the binding of cAMP to CRP induced about 50% quenching of the CRP fluorescence with a concomitant 3-nm blue shift from the original 336-nm emission peak. The binding of cGMP resulted in similar fluorescence changes but had no apparent effect on the pattern of proteolysis by trypsin. Using an in vitro transcription system known to be dependent on cAMP and Escherichia coli CRP, the synthesis of a run-off transcript product was also significantly enhanced by cAMP and this V. harveyi CRP.

Purification and characterization of an extracellular cytolysin produced by Vibrio damsela

Large amounts of an extremely potent extracellular cytolysin produced by the halophilic bacterium Vibrio damsela were obtained free of detectable contamination with medium constituents and other bacterial products by sequential ammonium sulfate precipitation, gel filtration with Sephadex G-100, and hydrophobic interaction chromatography with phenyl-Sepharose CL-4B. The cytolysin is heat labile and protease sensitive and has a molecular weight (estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) of ca. 69,000 and an isoelectric point of ca. 5.6. The first 10 amino-terminal amino acid residues of the cytolysin are Phe-Thr-Gln-Trp-Gly-Gly-Ser-Gly-Leu-Thr. The cytolysin was very active against erythrocytes from 4 of the 18 animal species examined (mice, rats, rabbits, damselfish) and against Chinese hamster ovary cells and was lethal for mice (ca. 1 microgram/kg, intraperitoneal median lethal dose). Lysis of mouse erythrocytes by the cytolysin is a multi-hit, at least two-step process consisting of a temperature-independent, toxin-binding step followed by a temperature-dependent, membrane-perturbation step(s).

Relation of capsular materials and colony opacity to virulence of Vibrio vulnificus

Colonies which varied in opacity were isolated from the four strains of Vibrio vulnificus. Opaque and translucent colonial types of the strains were distinguished from the corresponding parent strains. Variation in the opacity of colonies formed by each strain was accompanied by variation of capsular material formation, which was clarified by electron microscopy of the organisms stained with ruthenium red. The opaque-type colonies of the strains had capsular materials. On the other hand, three translucent-type colonies had no observable capsular materials, and one had incomplete capsular materials, in contrast to the corresponding opaque type. The corresponding opaque and translucent types of the strains were compared for points of virulence in mice and guinea pigs. By having capsular materials, the bacterial strains acquired resistance to serum bactericidal action, antiphagocytic activity, high lethality for mice, and strong invasiveness in the subcutaneous tissue of guinea pigs. Capsular materials of V. vulnificus were considered to be important for the expression of virulence.

Production and partial characterization of a Vibrio fluvialis cytotoxin

Conditions are described for the production of an extracellular cytotoxin or CHO cell-killing factor by Vibrio fluvialis, a recently recognized enteric pathogen. The cell-killing factor was ammonium sulfate precipitable, heat labile, and inactivated by proteases, and had an isoelectric point (estimated by sucrose density gradient electrofocusing) and an apparent molecular weight (estimated by gel filtration) of ca. 4.8 and 12,200, respectively. The culture supernatant fluids also possessed hemolytic and phospholipase A2 activities; however, they were separable from cell-killing factor activity by gel filtration. The substance(s) possessing the hemolytic and phospholipase activities coeluted when fractionated by gel filtration with Sephacryl S-200 (apparent molecular weight of ca. 34,500) and had isoelectric points of ca. 4.4 and 4.5, respectively.

Partial purification of extracellular toxic material of fish Vibrio

Hemolytic activity of 3 pathogenic strains, of fish Vibrio commonly associated with vibriosis (V anguillarum NCMB6 and NCMB571 strains, and Vibrio sp N7802 strain) was examined, using chicken and mammalian erythrocytes. Vibrio strains NCMB6 and NCMB571 and their culture filtrates had hemolytic activity against 8 kinds of erythrocytes tested, whereas Vibrio strain N7802 produced only a little amount of hemolysin. Strain NCMB571 culture filtrate and its material partially purified by column chromatography were lethal in mice. From 2 peaks of protein, hemolysin was recovered from the 1st peak, which coincided with toxicity in mice. Heat-inactivation of culture filtrate indicated that hemolytic materials may be thermolabile proteins, but that toxic material may be comparatively thermostable.

Purification of enterotoxins from Vibrio mimicus that appear to be identical to cholera toxin

Cholera toxin-like (CT-like) enterotoxins produced by two strains of Vibrio mimicus, 61892 and 63616, isolated from diarrhea patients in Bangladesh, were purified, and their physicochemical, biological, and immunological properties were compared with those of CT produced by classical Vibrio cholerae 569B. The CT-like toxins were produced by lincomycin-resistant mutants grown in the presence of lincomycin at 200 micrograms/ml for strain 63616 and 250 micrograms/ml for strain 61892 and were purified by coprecipitation with hexametaphosphate followed by chromatography on phosphocellulose. The pure CT-like toxins were indistinguishable from 569B CT in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, rabbit intestinal loop and Y-1 adrenal cell assays, antiserum neutralization and binding inhibition assays, and Ouchterlony immunodiffusion, except that the CT-like toxins appeared to consist almost entirely of A subunit which was proteolytically unnicked. Trypsin nicking, however, resulted in fragments that appeared to be identical to those of 569B CT. These results indicate that at least one species of Vibrio other than V. cholerae can produce enterotoxins which are virtually identical to CT.

The ribonucleotide sequence of 5s rRNA from two strains of deep-sea barophilic bacteria

Deep-sea bacteria were isolated from the digestive tract of animals inhabiting depths of 5900 m in the Puerto Rico Trench and 4300 m near the Walvis Ridge. Growth of two bacterial strains was measured in marine broth and in solid media under a range of pressures and temperatures. Both strains were barophilic at 2 degrees C (+/- 1 degrees C) with an optimal growth rate of 0.22 h-1 at a pressure 30% lower than that encountered in situ. At 1 atm they grew at temperatures ranging from 1.2 to 18.2 degrees C (+/- 0.3 degrees C), while in situ pressures increased the upper temperature limit to 23.3 degrees C. Both strains were identified as members of the genus Vibrio, based on standard taxonomic tests and mol% G + C values (47.0 and 47.1). Ribonucleotide sequences determined for 5S ribosomal RNA from each strain confirmed relationship to the Vibrio-Photobacterium group, as represented by V. harveyi and P. phosphoreum, but the barophiles were clearly distinct from these species. Secondary structure conformed to the established model for eubacterial 5S rRNA.

Characterization of the surface antigens of the marine fish pathogens Vibrio anguillarum and Vibrio ordalii

The technique of immunoblotting was used to identify the surface antigens of the marine vibrios pathogenic for fish, Vibrio anguillarum and Vibrio ordalii. Polyclonal antisera raised in rabbits to strains representing the two most common serotypes causing Vibriosis in fish in North America were used. The results demonstrated that antigenic specificity was conferred by the lipopolysaccharides, with three serotypes being displayed among the strains examined. The lipopolysaccharides of strains chosen as type species for V. anguillarum and V. ordalii displayed antigenic cross-reactivity. The morphological heterogeneity of the Vibrio lipopolysaccharides was also analyzed in silver-stained polyacrylamide gels and by intrinsic 32P-radiolabelling. Two distinct lipopolysaccharide morphologies were exhibited, one with 0 polysaccharide chains of heterogeneous chain length, the other having 0 polysaccharide chains of more uniform chain length but displaying microheterogeneity. These lipopolysaccharide morphologies corresponded to different serogroups. Two minor proteins of apparent molecular weights 49000-51000 present in outer membrane preparations isolated by the sarcosinate extraction procedure were also strong antigens, and common to all strains of V. anguillarum tested and to several strains of V. ordalii. The major outer membrane protein was a weak antigen common to both species.

The relationship between three potential pathogens and pollution indicator organisms in Nova Scotian coastal waters

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.

[DNA content in bacteria of the genera Bacillus, Pseudomonas, Proteus and Vibrio]

DNA content in bacterium Bacillus subtilis, Pseudomonas aeruginosa. Proteus vulgaris, Vibrio proteus at different growth condition has been studied. It has been shown that during the cultures growth DNA content is various independently of culture age and as a rule exceeds one chromosome weight and depends on growth condition.

Occurrence of uronic acid in lipopolysaccharides of Vibrionaceae

The occurrence of uronic acid as a sugar constituent of lipopolysaccharides (LPS) in Vibrionaceae was demonstrated for the first time. More than 100 strains were examined. Of five genera constituting Vibrionaceae, i.e., Vibrio, Aeromonas, Plesiomonas, Photobacterium, and Lucibacterium, the latter three contained uronic acid in LPS of all of their constituting members examined, while it was totally lacking in Aeromonas LPS so far tested. Only the members of genus Vibrio were found to be divided into uronic acid-containing and -lacking groups; V. parahaemolyticus, V. alginolyticus, V. fisheri, V. costicola, Beneckea ('Vibrio'), and V. fluvialis belonged to the former, while all four biotypes of V. cholerae regardless of their serotypes, V. vulnificus and V. anguillarum, belonged to the latter group. The uronic acid content of V. parahaemolyticus O1 to O12 LPS ranged from 1.6 to 4.2%. The uronic acid residue released from V. parahaemolyticus O1, O4, O10, and O12 LPS by heating in 5% acetic acid at 100 C for 2 hr was identified as galacturonic acid; in particular, that from O12 LPS was characterized as D-galacturonic acid.

Isolation and characterization of 3-acetamido-3,6-dideoxy-L-glucose from the core oligosaccharides obtained from the aquatic gram-negative bacteria Aeromonas hydrophila and Vibrio anguillarum

The amino sugar 3-acetamido-3,6-dideoxy-L-glucose has been isolated and characterized from the core oligosaccharide obtained from the bacterial lipopolysaccharides of Aeromonas hydrophila and Vibrio anguillarum. This is the first occasion in which a dideoxyamino sugar has been confirmed as a constituent of the core oligosaccharide rather than the O-polysaccharide.

Polyacrylamide gel electrophoresis and infrared spectroscopy of vibrio biotypes

Polyacrylamide gel electrophoresis and infrared spectroscopy were used to study the relationship between Vibrio cholerae (classical), Vibrio cholerae (El Tor), and nonagglutinable (NAG) vibrios. Acid extracts of the different strains produced type-specific electrophoretic patterns, and the infrared spectra revealed broad absorption maxima which largely correspond to those found in other organisms. With the exception of the NAG vibrios, the infrared spectra of cholera El Tor vibrios were identical. Strain-specific differences were found in the exoprotein spectra of these organisms by the sodium dodecyl sulphate - polyacrylamide gel electrophoretic technique.

[Characteristics of the heat-stable enterotoxin of NAG vibrios]

Cell-free culture filtrate boiled for 15 minutes has been found to retain its biological activity in various experimental models used for the determination of the toxicogenicity of cholera vibrio filtrates. During gel filtration of the concentrated filrate o. NAG vibrio, strain NO. 9852, through Sephadex G-75 toxic activity could be detected in the free volume of the column, which was indicative of the fact that the molecular weight of the thermostable enterotoxin was about 70,000 daltons and greater. The methods of gel diffusion and aggregated hemagglutination have been used to show that the thermostable enterotoxin of NAG vibrio No. 9852 is immunologically unrelated to cholerogen. Some data obtained in experimental models suggest that the thermostable enterotoxin probably differs from cholera enterotoxin in the mechanism of its action.

[Similarity of the DNA mucleotide sequences of vibrios]

The systematic position of some Vibrio species was ascertained by the method of molecular DNA -- DNA hybridization. The DNA of the brine vibrios V. costicola and V. fischeri were shown to have about 10% of sequences homologous with DNA of a typical cholera vibrio (V. cholerae eltor No. 334). Similarity between the genomes of other representatives of the Vibrionaceae family, as well as in DNA hybridization of V. costicola and V. fischeri, was found to be approximately on the same level. All species included into the genus, Vibrio on account of their phenotypic characteristics may be considered to have essential differences in the structures of their genomes.

The N-terminal sequence of the ribosomal 'A' protein from two moderate halophiles, Vibrio costicola and an unidentified moderate (NRCC 11227)

The 'A' protein, equivalent to ribosomal protein EL7/L12 from Escherichia coli, has been isolated and purified from two moderate halophiles Vibrio costicola and NRCC 11227. The 'A' protein from V. costicola contained an N-terminal serine and separated into two forms on DEAE-cellulose and two-dimensional electrophoresis while the equivalent protein in NRCC 11227 contained an N-terminal alanine residue and was present in only one form. The amino acid composition and mobility on two-dimensional gels indicated these proteins were very similar to EL7/L12. The first 38 residues of the 'A' proteins were sequenced and compared to the equivalent protein from E. coli and the extreme halophile Halobacterium cutirubrum. The N-terminal region of the 'A' protein from both moderate halophiles showed substantial homology to EL 12 (75--80%) but no evidence of any homology to the equivalent protein from the extreme halophile. The ribosomal proteins equivalent to ES1A in E. coli were also isolated and their amino acid compositions determined.

The 4-amino sugars present in the lipopolysaccharides of vibro cholerae and related vibrios

Brief treatment, with 10 M hydrochloric acid, of the lipopolysaccharides of Vibrio cholerae and related organisms led to the release of 4-amino-4, 6-dideoxy-D-mannose (D-perosamine) and 4-amino-4-deoxyl-L-arabinose. These sugar are highly unstable and undergo complex changes in neutral and basic media. Of the strains examined, the lipopolysaccharides from representatives of the Inaba group contain only D-perosamine, while those of the Ogawa biotype have 4-amino-4-deoxyl-L-arabinose as an additional component. The other Vibrios produce lipopolysaccharides which lack these sugars.

An ancient divergence among the bacteria

The 16S ribosomal RNAs from two species of methanogenic bacteria, the mesophile Methanobacterium ruminantium and the thermophile Methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with T1 ribonuclease. These two organisms are found to be sufficiently related that they can be considered members of the same genus or family. However, they bear only slight resemblance to "typical" Procaryotic genera; such as Escherichia, Bacillus and Anacystis. The divergence of the methanogenic bacteria from other bacteria may be the most ancient phylogenetic event yet detected--antedating considerably the divergence of the blue green algal line for example, from the main bacterial line.

Cell-bound cations of the moderately halophilic bacterium Vibrio costicola

Over most of the range of salt concentrations in which the moderately halophilic bacterium Vibrio costicola could grow, the sum of the cell-associated Na+ + K+ ions was at least as high as in the external medium. This is in contrast to other moderate halophiles, which have substantially lower internal than external salt concentrations for most of their growth range. The relative amounts of Na+ and K+ in V. costicola varied with environmental conditions. The K+/Na+ ratio fell during anaerobic incubation or when cells were poisoned. As Na+ ions left the cells, K+ ions entered. However, movement of these ions was not tightly coupled, since K+ content of cells could increase without a corresponding decrease in Na+ content. The Mg2+ contents of cells varied little with environmental conditions.

Amino sugar contents and phage inactivating properties of lipopolysaccharide from cholera and El Tor vibrios

Cholera and El Tor lipopolysaccharide (LPS) were identical in respect of chemical composition except that the hexosamine content was significantly lower and galactosamine was absent in El Tor LPS. Mukerjee's group IV cholera phage phi149 was inactivated by cholera LPS but was resistant to El Tor LPS.

[Modification of Schmidt-Tannhauser's method of bacterial nucleic acid fractionation]

It was revealed that in fractionation of nucleic acids by Schmidt-Tannhauser's method up to 90% of the DNA of bacteria was destroyed in the course of alkaline hydrolysis changing into the RNA fraction (the alkali-labile fraction of the DNA). The authors suggest a modification of the method based on the precipitation of the alkali-labile DNA fraction from the RNA fraction with ethanol. This modified method permits to record over 96% of all the cell DNA of bacteria.

Study of genetic relationships among marine species of the genera Beneckea and Photobacterium by means of in vitro DNA/DNA hybridization

Strains representative of species of the marine genera Beneckea and Photobacterium were used as reference standards in in vitro DNA/DNA competition experiments. Within a given species, strains were found to be related by over 80% competition. (Competition was defined as the amount of radioactive DNA displaced by heterologous DNA relative to the amount displaced by homologous DNA.) On the basis of interspecies competition values (expressed as averages), the following groupings could be made: 1. "Photobacterium" fischeri was related to strain ATCC 15382 by a competition of 38% and was distinct from all the other strains tested (competition less than or equal to 11%). 2. The genus Photobacterium consisted of 3 species, P.phosphoreum, P.leiognathi, and a newly designated species, P.angustum (composed of non-luminous strains). The latter species was found to be related to P.leiognathi and P.phosphoreum by 56 and 28% competition, respectively, while P.phosphoreum was related to P.leiognathi by 29%. 3. In the genus Beneckea, 65% competition was detected between B.harveyi and B.campbellii as well as between B.parahaemolytica and B.alginolytica. These pairs of species were related to each other by 51-58% and to B.natriegens by 34-56% competition. A newly designated pathogenic species, B.vulnifica, appeared to have a low but significant relationship to all the above mentioned species of Beneckea. 4. Two biotypes, related by 68% competition, were recognized in the species B.splendida. Similarly, B.pelagia was found to consist of 2 biotypes related by a competition of 67%. The competition values between these species were 38-40%. 5. B.nereida, B.nigrapulchrituda, and "Vibrio" anguillarum had competition values less than or equal to 30% to each other as well as to other species of Beneckea. 6. With Vibrio cholerae as the reference standard, V.albensis was found to be related by a competition of 82%, while V.proteus and V.metschnikovii had competition values of 22 and 12%, respectively. These results suggested that V.albensis should be synonymized with V.cholerae, while the latter two organisms should remain distinct from this species. V.cholerae as well as the other terrestrial organisms tested did not appear to be significantly related to any of the marine strains (competition values less than or equal to 27%). The speciation derived from the results of the DNA/DNA competition experiments was compared to previous speciation based on phenotypic similarities.

[Comparative study of the proteinograms of vibrios and of closely related microorganisms by means of polyacrylamide gel disc electrophoresis]

Proteinograms of 112 strains of vibrios and closely affiliated microorganisms were studied by disc electrophoresis in polyacrylamide gel. Up to 25 protein peaks with definite mobility coefficients were revealed. The influence of the culture medium on the protein spectrum of the microbes was found. The frequency of peak formation was of great significance for the differentiation of the microbes under study. The quantitative characteristics of the peak area could not be used for differentiation.