The biology of Zymomonas.

One-hundred-and-forty-five isolates of marine origin were submitted to an extensive physiological, nutritional, and morphological characterization. All strains were gram-negative, facultatively anaerobic, straight or curved rods which were motile by means of flagella. Glucose was fermented with the production of acid but no gas. Sodium but no organic growth factors were required. None of the strains were able to denitrify or fix molecular nitrogen. The results of nutritional and physiological tests were submitted to a numerical analysis. On the basis of phenotypic similarity, nine groups were established. These groups could be distinguished from one another by multiple, unrelated, phenotypic traits. Six groups which had deoxyribonucleic acid (DNA) containing 45 to 48 moles per cent guanine plus cytosine (GC) were assigned to a redefined genus Beneckea . All of the strains in this genus, when grown in liquid medium, had a single, polar flagellum. When grown on a solid medium, many strains had peritrichous flagella. Two groups were similar to previously described species and were designated B. alginolytica and B. natriegens . The remaining four groups were designated B. campbellii, B. neptuna, B. nereida , and B. pelagia . An additional group of phenotypically similar strains having the properties of the genus Beneckea was not included in the numerical analysis. These strains were readily separable from species of this genus and were designated B. parahaemolytica . Of the remaining groups, one was identified as Photobacterium fischeri . The other group (B-2) which had about 41 moles% GC content in its DNA could not be placed into existing genera. Images

Taxonomy of Marine Bacteria: the Genus Beneckea

A serotyping scheme based on the detection of O antigens by slide agglutination in fish-pathogenic strains of Vibrio anguillarum is presented. Over a period of 5 years 270 Vibrio strains from feral and cultured fish, 189 strains from the environment, and 36 strains from invertebrates were collected. The strains were divided into 10 distinct serotypes (O1 through O10). More than 90% of the fish-pathogenic strains, but only 40% of the environmental strains, were typable; 71% of the strains isolated from cultured rainbow trout were serotype O1, whereas 78% of the strains isolated from feral fish were serotype O2. No dominating environmental serotype was found. A serotyping system for V. anguillarum is proposed. A total of 90 strains received from culture collections and laboratories in different countries were typed according to the present system.

Serotyping of Vibrio anguillarum.

A review of the literature shows that although the number of serotypes of Vibrio anguillarum reported from different countries varies, most of the vibriosis outbreaks throughout the world are caused by only 2 serotypes: 01 and 0 2 (European serotype designation). The remaining serotypes, associated mainly with environmental samples such as water, sediment, phytoand zooplankton, are generally non-pathogenic to fish. This raises the question as to whether the 2 major pathogenic serotypes of V. anguillarum (isolated only from diseased or carrier fish) should be considered opportunistic or obligate fish pathogens. In addition, information useful in epizootiological and vaccination studies is presented about the antigenic heterogeneity detected within serotype 0 2 . In this review, emphasis is placed on the presence in the marine environment of vibrios (presumptively assigned to the V. splendidus and V. pelagius) species that are taxonomically and serologically related with V. anguillarum and some of which have been associated with disease in fish cultured on the Atlantic coast of Spain and Norway. The precise phylogenetic position of these V. anguillarum-like organisms are well as their actual threat to marine aquaculture remains to be clarified.

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A review of the taxonomy and seroepizootiology of Vibrio anguillarum, with special reference to aquaculture in the northwest of Spain

. A total of 517 Vibrio anguillarum strains isolated from discased fish together with 14 V. anguillarum serogroup O2 and V. ordalii type strains were serotyped using the European scrotyping system. Marked species differences were recorded. In isolates from salmonids serovar O1 (70.2%) and O2 (20.2%) were dominantwhilst a minor proportion belonged to other serogroups or were non-typeable. Figures for turbot were similar to those from salmonids. In 32 isolates from sea bass, sea bream and mullet, most strains belonged to serogroup O1. while one was O2a. one O7, and the rest non-typeable In cod serovar O2 was dominant while only a minor proportion belonged to other serogroups or were non-typeable. The ecl isolates belonged equally to serovars O2 and O3. All O2 strain were subtyped with absorbed O2a and O2b antisera. O2a was dominant in all fish species. but in cod. the relative number of O2b isolates was considerably higher than in other fish species. The applicability of the European serotyping system is discussed and compared with other serotyping systems.

Vibrio anguillarum serovars associated with vibriosis in fish

Cultural characteristics and serological relationships of pathogenic marine vibrios isolated from fish in the Pacific Northwest were studied. These organisms were compared with cultures of Vibrio anguillarum, a known fish pathogen. On the basis of morphological and cultural characteristics, the Pacific Northwest strains of Vibrio were found to be closely related to V. anguillarum. Serological analyses of thermostable antigens served to distinguish three serotypes among the vibrios. Serotype 1 was composed of organisms isolated from Northwest salmonids; serotype 2 of strains of V. anguillarum from European waters; and serotype 3 of organisms isolated from Pacific herring. The epidemiology of vibrio disease among populations of fish in the Pacific Northwest is discussed.

Characterization and Relatedness of Marine Vibrios Pathogenic to Fish: Physiology, Serology, and Epidemiology

Deoxyribonucleic acid (DNA) isolated from several pathogenic marine vibrios was utilized in studies of base composition and nucleotide sequence relationships. Patterns of relatedness inferred from DNA criteria were found to correlate closely with those inferred from morphological, physiological, and serological analysis of the same organisms. The utility of the phenotypic and genotypic approaches to the determination of relatedness is discussed.

R. E. Pacha

Papers

Characterization and Relatedness of Marine Vibrios Pathogenic to Fish: Physiology, Serology, and Epidemiology

Characterization and relatedness of marine vibrios pathogenic to fish: deoxyribonucleic acid homology and base composition.