Taxonomic composition of bacteria associated with cultivated mollusks <Emphasis Type="Italic">Crassostrea lugubris</Emphasis> and <Emphasis Type="Italic">Perna viridis</Emphasis> and with the water of the Gulf of Nha Trang lagoon,Vietnam

One hundred and four strains of heterotrophic bacteria have been isolated and characterized from two species of bivalve mollusks cultivated in the Gulf of Nha Trang (Vietnam) and from the water of a mariculture farm. The isolates have been identified on the basis of morphological, physiological, biochemical, and chemotaxonomic properties, as well as by the content of G+C bases in DNA. In the microflora of mollusks, Vibrio alginolyticus was predominant; the pathogenic species V. harveyi and V. splendidus were found as well. Staphylococci and bacilli occupied the second place in abundance after vibrios. In addition, coryneforms and enterobacteria, as well as Pseudomonas spp. and Pseudoalteromonas spp., were revealed. The composition of the water microflora was more diverse as compared with the microflora of mollusks. In the water, Bacillus spp., Vibrio spp., and Pseudomonas spp. were predominant. Brevibacterium spp. and other coryneform bacteria, as well as enterobacteria, occurred in significant amounts. In addition, Pseudoalteromonas spp., Marinococcus sp., Halobacillus sp., Shewanella sp., Sulfitobacter sp., and bacteria of the CFB cluster were noticed. The presence of pathogenic and conditionally pathogenic bacterial species in the water and mollusks is probably the reason for the high death rate of cultivated animals at the mariculture farm.     

Bacterial communities of brown and red algae from Peter the Great Bay, the Sea of Japan

The structure of microbial communities of brown algae, red algae, and of the red alga Gracilaria verrucosa, healthy and affected with rotten thallus, were comparatively investigated; 61 strains of heterotrophic bacteria were isolated and characterized. Most of them were identified to the genus level, some Vibrio spp., to the species level according to their phenotypic properties and the fatty acid composition of cellular lipids. The composition of the microflora of two species of brown algae was different. In Chordaria flagelliformis, Pseudomonas spp. prevailed, and in Desmarestia viridis, Bacillus spp. The composition of the microflora of two red algae, G. verrucosa and Camphylaephora hyphaeoides, differed mainly in the ratio of prevailing groups of bacteria. The most abundant were bacteria of the CFB cluster and pseudoalteromonads. In addition, the following bacteria were found on the surface of the algae: Sulfitobacter spp., Halomonas spp., Acinetobacter sp., Planococcus sp., Arthrobacter sp., and Agromyces sp. From tissues of the affected G. verrucosa, only vibrios were isolated, both agarolytic and nonagarolytic. The existence of specific bacterial communities characteristic of different species of algae is suggested and the relation of Vibrio sp. to the pathological process in the tissues of G. verrucosa is supposed.     

Bacterial communities of some brown and red algae from Peter the Great Bay, the Sea of Japan

The structure of microbial communities of brown algae, red algae, and of the red alga Gracilaria verrucosa, healthy and affected with thallus rot, were comparatively investigated; 61 strains of heterotrophic bacteria were isolated and characterized. Most of them were identified to the genus level, some Vibrio spp., to the species level according to their phenotypic properties and the fatty acid composition of cellular lipids. The composition of the microflora of two species of brown algae was different. In Chordaria flagelliphormis, Pseudomonas spp. prevailed, and in Desmarestia viridis, Bacillus spp. The composition of the microflora of two red algae, G. verrucosa and Camphylaephora hyphaeoides, differed mainly in the ratio of prevailing groups of bacteria. The most abundant were bacteria of the CFB cluster and pseudoalteromonads. In addition, the following bacteria were found on the surface of the algae: Sulfitobacter spp., Halomonas spp., Acinetobacter sp., Planococcus sp., Arthrobacter sp., and Agromyces sp. From tissues of the affected G. verrucosa, only vibrios were isolated, both agarolytic and nonagarolytic. The existence of specific bacterial communities characteristic of different species of algae is suggested and the relation of Vibrio sp. to the pathological process in the tissues of G. verrucosa is supposed.     

Life cycle of tetrodotoxin-producing <Emphasis Type="Italic">Bacillus</Emphasis> sp. on solid and liquid medium: Light and electron microscopy studies

The lifecycle of the Bacillus sp. 1839 cultivated during a long period on solid and liquid Youschimizu-Kimura medium was investigated, and then bacteria and spores were studied by light and transmission electron microscopy. Sporulation in this strain is distinguished by engulfment of forespore by mother cell. In the liquid medium, bacteria have the decondensed nucleoid and the loose granular component of cytoplasm; bacteria and spores are generally smaller; the outer coat of spores includes 2 concentric rings. On the solid substratum, the nucleoid is condensed, and the cytoplasmic region is extensive and dense; a longer cultivation stimulates transition of vegetative cells into the spore form; spores have a thicker outer coat with 3–5 rings. On the solid substratum, sporulation in Bacillus sp. 1839 is spontaneous, without additional stimulation; spores have a larger diameter and thicker layers than those in the liquid medium. This research contributes to the current understanding of biotechnological tetrodotoxin production from a bacterial raw material.     

The Vibrioflora of Hydrobionts and Waters of the Sea of Japan (Peter the Great Bay) and the South China Sea (Nha Trang Bay)

Russian Journal of Marine Biology - Strains of Vibrio spp. isolated from samples of water and aquatic organisms of the temperate (173&nbsp;strains) and tropical (124 strains) climatic zones...     

Comparative study of microbial communities from cultured and natural population of the mussel Mytilus trossulus in Peter the Great bay

The 525 strains of heterotrophic bacteria isolated from natural and cultured populations of the mussel Mytilus trossulus and the surrounding seawater were identified to a genus level on the basis of phenotypic analysis and the fatty acid composition of cell lipids. Gram-negative isolates were dominated by six genera of the family Enterobacteriaceae and by the genera Pseudoalteromonas, Vibrio, Photobacterium, Cytophaga/Flavobacterium/Bacteroides, Pseudomonas, and Moraxella, Gram-positive isolates were mainly represented by the genus Streptomyces. The taxonomic compositions of natural and cultured populations of the mussel M. trossulus in Peter the Great Bay were similar.     

Taxonomic composition of bacteria associated with cultivated mollusks Crassostrea lugubris and Perna viridis and with the water of the Gulf of Nha Trang Lagoon, Vietnam

One hundred and four strains of heterotrophic bacteria have been isolated and characterized from two species of bivalve mollusks cultivated in the Gulf of Nha Trang (Vietnam) and from the water of a mariculture farm. The isolates have been identified on the basis of morphological, physiological, biochemical, and chemotaxonomic properties, as well as by the content of G+C bases in DNA. In the microflora of mollusks, Vibrio alginolyticus was predominant; the pathogenic species V. harveyi and V. splendidus were found as well. Staphylococci and bacilli occupied the second place in abundance after vibrios. In addition, coryneforms and enterobacteria, as well as Pseudomonas spp. and Pseudoalteromonas spp., were revealed. The composition of the water microflora was more diverse as compared with the microflora of mollusks. In the water, Bacillus spp., Vibrio spp., and Pseudomonas spp. were predominant. Brevibacterium spp. and other coryneform bacteria, as well as enterobacteria, occurred in significant amounts. In addition, Pseudoalteromonas spp., Marinococcus sp., Halobacillus sp., Shewanella sp., Sulfitobacter sp., and bacteria of the CFB cluster were noticed. The presence of pathogenic and conditionally pathogenic bacterial species in the water and mollusks is probably the reason for the high death rate of cultivated animals at the mariculture farm.     

Distribution and characteristics of Bacillus bacteria associated with hydrobionts and the waters of the Peter the Great Bay, Sea of Japan

Bacilli of the species Bacillus subtilis, B. pumilus, B. mycoides, B. marinus and B. licheniformis (a total of 53 strains) were isolated from 15 invertebrate species and the water of the Vostok Bay, Peter the Great Bay, Sea of Japan. Bacilli were most often isolated from bivalves (22.7%) and sea cucumbers (18.9%); they occurred less frequently in sea urchins and starfish (13.2 and 7.5%, respectively). Most of bacilli strains were isolated from invertebrates inhabiting silted sediments. No Bacillus spp. strains were isolated from invertebrates inhabiting stony and sandy environments. The species diversity of bacilli isolated from marine objects under study was low. Almost all bacterial isolates were resistant to lincomycin. Unlike B. pumilus, B. subtilis isolates were mostly resistant to benzylpenicillin and ampicillin. Antibiotic sensitivity of B. licheniformis strains was variable (two strains were resistant to benzylpenicillin and oxacillin, while one was sensitive). A significant fraction of isolated bacilli contained pigments. Pigmented strains were more often isolated from seawater samples, while colorless ones predominated within hydrobionts. B. subtilis colonies had the broadest range of colors. In the Bacillus strains obtained, DNase, RNase, phosphatase, elastolytic, chitinase, and agarolytic activity was detected. Bacilli strains with hydrolytic activity occurred in invertebrates more often than in seawater.     

Physiological and Biochemical Characteristics of the Halophilic Bacteria Vibrio parahaemolyticus and V. alginolyticus Isolated from Marine Invertebrates of Peter the Great Bay, Sea of Japan

One hundred strains of halophilic vibrios were isolated from 16 species of marine invertebrates of Peter the Great Bay. Based on their morphological and biochemical characteristics, the bacteria were identified as Vibrio parahaemolyticus and Vibrio alginolyticus. Bacterial isolates possessed virulence enzymes (DNAase, lecithinase, catalase) and were characterized by a high enterotoxigenicity. It was determined that 76% of the V. parahaemolyticus strains and 43% of the V. alginolyticus strains were Kanagawa-positive. The isolates showed a high adhesive capability, the average adhesion index was 18.06 cells per erythrocyte for V. parahaemolyticus and 12.55 for V. alginolyticus. The results of this study suggest a high pathogenic potential of the isolated halophilic vibrios, which are an epidemic hazard to marine invertebrates and to humans.