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R R Colwell

Publications and source records attributed to R R Colwell.

At least 289 records · Page 16Linked to original sources
PubMed1970

Intracytoplasmic membrane structures in Vibrio marinus.

An electron microscope study of Vibrio marinus strains MP-1, an obligate psychrophile, and PS-207, a moderate psychrophile, revealed numerous intracellular membranous structures. The structures were found to occur more frequently in V. marinus strain MP-1 than in strain PS-207. The frequency of occurrence and complexity of structure were related to age of the culture. In early logarithmic phase, cells revealed invaginations of the plasma membrane. More complex membrane forms, found in late logarithmic and stationary phase, were either myelin-like sheaths, for which the term "myelemma" is proposed, or membranes randomly arranged throughout the cells. The complex membrane forms were not observed to be directly connected with the plasma membrane. However, they were often found in approximation to the plasma membrane or associated with vacuoles and circular membrane profiles. Individual membranes were of a tripartite structure and of dimensions similar to the cell wall and plasma membrane.

Bacteriological Techniques↗
PubMed1970

Polyphasic taxonomy of the genus vibrio: numerical taxonomy of Vibrio cholerae, Vibrio parahaemolyticus, and related Vibrio species.

A set of 86 bacterial cultures, including 30 strains of Vibrio cholerae, 35 strains of V. parahaemolyticus, and 21 representative strains of Pseudomonas, Spirillum, Achromobacter, Arthrobacter, and marine Vibrio species were tested for a total of 200 characteristics. Morphological, physiological, and biochemical characteristics were included in the analysis. Overall deoxyribonucleic acid (DNA) base compositions and ultrastructure, under the electron microscope, were also examined. The taxonomic data were analyzed by computer by using numerical taxonomy programs designed to sort and cluster strains related phenetically. The V. cholerae strains formed an homogeneous cluster, sharing overall S values of >/=75%. Two strains, V. cholerae NCTC 30 and NCTC 8042, did not fall into the V. cholerae species group when tested by the hypothetical median organism calculation. No separation of "classic" V. cholerae, El Tor vibrios, and nonagglutinable vibrios was observed. These all fell into a single, relatively homogeneous, V. cholerae species cluster. V. parahaemolyticus strains, excepting 5144, 5146, and 5162, designated members of the species V. alginolyticus, clustered at S >/=80%. Characteristics uniformly present in all the Vibrio species examined are given, as are also characteristics and frequency of occurrence for V. cholerae and V. parahaemolyticus. The clusters formed in the numerical taxonomy analyses revealed similar overall DNA base compositions, with the range for the Vibrio species of 40 to 48% guanine plus cytosine. Generic level of relationship of V. cholerae and V. parahaemolyticus is considered dubious. Intra- and intergroup relationships obtained from the numerical taxonomy studies showed highly significant correlation with DNA/DNA reassociation data.

Alcaligenes↗
PubMed1970

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.

Centrifugation, Density Gradient↗
PubMed1969

Numerical Taxonomy of Heterotrophic Bacteria Growing in Association with Continuous-Culture Chlorella sorokiniana.

Twenty-nine cultures isolated from nonaxenic growths of Chlorella sorokiniana (Shihira and Krauss) and eight reference cultures were tested for 150 morphological and biochemical characteristics. The taxonomic data were subjected to computer analysis from which five major clusters were identified. The bacterial isolates have been placed in the genera: Pseudomonas, Acinetobacter, Flavobacterium, and Bacillus. Amino acid requirements of four strains from the test set were determined.

Journal Article↗
PubMed1969

Morphology and round body fermation in Vibrio marinus.

The morphology of Vibrio marinus MP-1 was studied by phase and electron microscopy. The ultrastructure of the vibrio form of V. marinus was found to be typically gram-negative with a trilaminar plasma membrane and cell wall. The coccoid or round bodies noted in otherwise pure cultures of V. marinus were frequently found in early and late stationary phase of growth. The round bodies in ultrathin section were found to contain at least one, and often three or four, cell units. Three types of round bodies were observed in ultrathin section, each differing in size and behavior: "spherules," "spheres" or the "round body," and "giant cells" or "macrospheres." The round bodies appeared to be associated with, or to result from, the constrictive cell division of V. marinus.

Cell Division↗
PubMed1968

Numerical taxonomy of catalase-negative cocci isolated from frozen vegetables.

Taxonomic data for 135 cultures of bacteria isolated from frozen snap beans and whole kernel corn were analyzed by computer. Of the isolates, 79% were grouped into five major clusters. Two of the groups consisted of leuconostocs, whereas the other three contained homofermentative types. The intergroup similarities suggested a generic level of similarity. Feature frequencies for the groups were calculated, and properties of the different groups are presented. Many of the isolates differed from described species.

Bacteria↗
PubMed1968

Properties of bacteria isolated from deep-sea sediments.

Thirty-eight isolates were subjected to taxonomic analysis by computer. Of the 38 isolates, 31 were from sediment samples collected at depths from 9,400 to 10,400 meters in the Philippine and Marianas Trenches of the Pacific Ocean, and 7 cultures were from seawater samples collected at various depths from surface to 4,000 meters and from several locations in the Pacific Ocean. A total of 116 characteristics were determined for each isolate, coded, and transferred to punch cards. Similarity values were obtained by computer analysis, with the use of two recently developed computer programs. Five distinct phenetic clusters were observed from the numerical analyses. Four of the clusters were identified as species of the genus Pseudomonas, and one, as an aerogenic species of Aeromonas. Group IV was identified as pigmented Pseudomonas fluorescens, and the major cluster, consisting of groups I and II, which merged at a species level of similarity, was treated as a new species of Pseudomonas. The 38 strain data were compared with data for 132 marine and nonmarine strains previously subjected to computer taxonomic analysis. The barotolerant deep-sea strains, with the exception of the deep-sea P. fluorescens isolates, clustered separately from all other marine strains.

Aeromonas↗
PubMed1967

Numerical taxonomy of gram-positive and catalase-positive rods isolated from frozen vegetables.

One hundred isolates from peas, beans, and corn were compared with cultures of Corynebacterium, Microbacterium, and Arthrobacter by use of numerical taxonomic procedures. Six groups (clusters), representing 75% of the isolates, resembled Corynebacteriaceae. There was some doubt regarding the genera represented because the groups were not closely related to many of the known strains. The relationship of the different groups to each other, as well as a number of their properties, is presented.

Arthrobacter↗
PubMed1967

Properties of Pseudomonas enalia, a marine bacterium pathogenic for the invertebrate Crassostrea gigas (Thunberg).

Bacteriological investigations of dead and dying oysters in populations of Crassostrea gigas grown in Hood Canal, Oyster Bay, and Willapa Bay, Washington, were undertaken. Living, and presumably normal, oysters within the same sample set were also examined. Results indicated that the natural flora of Crassostrea gigas (Thunberg) is composed of organisms representing the genera Pseudomonas, Achromobacter, Flavobacterium, and Vibrio. Pollution indicator organisms such as Escherichia coli were not found. The flora of dead or dying oysters included a somewhat greater incidence of Pseudomonas sp.; a seawater-requiring organism isolated on several occasions from oyster gapers which had been collected from different geographical areas was identified as P. enalia. A description of the organism has been provided, and the characteristics are listed to facilitate identification by other workers encountering the organism in future studies of a similar kind. The seawater requirement exhibited by P. enalia was deduced to be a requirement for sodium chloride for growth of the organism. Experiments to determine the pathogenicity of Pseudomonas enalia were performed by use of experimentally infected animals maintained in aerated seawater tanks. Death of C. gigas occurred when the animal body tissue was injected with viable bacterial cell suspension. Results of histological studies of the normal and infected oyster tissue suggest that bacterial invasion of the tissue occurred.

Alcaligenes↗