Identification and analysis of the biological activity of the new strain of Pseudoalteromonas piscicida isolated from the hemal fluid of the bivalve Modiolus kurilensis (F. R. Bernard, 1983).

A cultivated form of bacteria (strain 2202) was isolated from the hemal fluid of the bivalve mollusk Modiolus kurilensis. Based on the set of data collected by genetic and physiological/biochemical analyses, the strain was identified as the species Pseudoalteromonas piscicida. Strain 2202 exhibits antimicrobial activity against Staphylococcus aureus, Candida albicans, and Bacillus subtilis but not against Escherichia coli and Pseudomonas aeruginosa. These activities characterize the behavior of strain 2202 as predator-like and classify it as a facultative predator. Being part of the normal microflora in the hemolymph of M. kurilensis, when external conditions change, strain 2202 shows features of opportunistic microflora. The strain 2202 exhibits selective toxicity towards larvae of various invertebrates: it impairs the early development of Mytilus edulis, but not of Strongylocentrotus nudus. Thus, the selective manner in which P. piscicida strains interact with various species of microorganisms and eukaryotes should be taken into consideration when using their biotechnological potential as a probiotic in aquaculture, source of antimicrobial substances, and factors that prevent fouling.

The tellurite-reducing bacterium Alteromonas macleodii from a culture of the toxic dinoflagellate Prorocentrum foraminosum.

The Alteromonas macleodii strain 2328 was isolated from a clonal culture of the toxic dinoflagellate Prorocentrum foraminosum. The strain exhibits a resistance to high K2TeO3 concentrations (2500 µg/mL). A study of the growth dynamics of the strain exposed to K2TeO3 has shown a longer lag phase and a reduced stationary phase compared to those during cultivation with no toxicant. The fatty acids profile is dominated by 16:1 (n-7), 16:0, 17:1, 15:0, 18:1 (n-7), and 17:0. The 2328 strain belongs to the Gammaproteobacteria and is related to the genus Alteromonas with 99-100% sequence similarity to some intra-genome allele variants (paralogues) of 16S rRNA from A. macleodii. A phylogenetic reconstruction (ML and NJ), based on HyHK amino acid sequences, has revealed that the analyzed 2328 strain forms a common cluster with A. macleodii strains. In the presented work, the ability of A. macleodii to reduce potassium tellurite to elemental tellurium has been recorded for the first time. Bacteria reduce potassium tellurite to Te (0), nanoparticles of which become distributed diffusely and in the form of electron-dense globules in cytoplasm. Large polymorphous metalloid crystals are formed in the extracellular space. Such feature of the A. macleodii strain 2328 makes it quite attractive for biotechnological application as an organism concentrating the rare metalloid.

Tetrodotoxin-producing Bacillus sp. from the ribbon worm (Nemertea) Cephalothrix simula (Iwata, 1952).

Specimens of the toxic ribbon worm Cephalothrix simula from the Sea of Japan were screened for tetrodotoxin-producing bacteria. A single TTX-producing bacterial strain (No 1839) was isolated from tissues of C. simula and studied by immunohistochemical methods (including immunoelectron and immunofluorescent microscopies) with anti-TTX antibodies. Sequencing of 16S rRNA gene of the strain 1839 showed that it is most likely Bacillus sp. CU040510-015 and Bacillus asahii. Based on its morphological and biochemical properties, however we suppose that the isolated Bacillus sp. 1839 should be classified as representing a new species. Microdistribution of TTX in bacterial cell was investigated under electron microscope by immunoenzymatic methods. TTX was concentrated in the forespore and free spores, but it was not detected in the vegetative cells of Bacillus sp. 1839. We suggest that release of free mature spores from sporangium of Bacillus sp. 1839 leads to appearance of toxin in tissues of C. simula. Confocal laser-scanning microscopy (CLSM) method with anti-TTX antibodies can be recommended for preliminary detection of apparent TTX accumulation.

Incidence and characteristics of Staphylococcus aureus and Listeria monocytogenes from the Japan and South China seas.

The distribution of Staphylococcus aureus and Listeria monocytogenes in the sea water and marine organisms of Peter the Great and Nha Trang bays, the phenotypic properties and antibiotic sensitivity of the isolates were studied. S. aureus was recorded from 9.3% samples in the Sea of Japan and from 20.4% samples in the South China Sea, L. monocytogenes respectively from 5.9 % and 5.8 % samples. S. aureus and L. monocytogenes found in the tropics differed in their phenotypic properties from those found in the temperate zone. Antibiotic resistance was detected in 81.8% and 71.8% of S. aureus strains and in 19% and 71.4% of L. monocytogenes strains respectively from Peter the Great Bay and from Vietnam. The results show that multiresistant strains of S. aureus and L. monocytogenes are widespread throughout Peter the Great and Nha Trang bays and present a hazard to the health of humans and marine animals.

Biochemical and pathogenic properties of the natural isolate of Shewanella algae from Peter the great bay, sea of Japan.

Pathogenic properties of the natural isolate of Shewanella algae from the coelomic fluid of the sea cucumber Apostichopus japonicus (Peter the Great Bay, Sea of Japan) were investigated. The isolate had oxydative metabolism, was positive for ornithine decarboxylase, cytochrome oxidase, catalase, DNase and gelatinase, hemolytically active, did not produce acid from carbohydrates, and did not hydrolyze urea and esculin. The strain was resistant to penicillin, amoxicillin, and ampicillin and susceptible to tetracycline and carbenicillin. Among cellular fatty acids, 13:0-i, 15:0-i, 16:0, 16:1(n-7), 17:0-i, and 17:0-ai dominated. These biochemical properties made it possible to attribute the isolated bacteria to the genus Shewanella and identified as S. algae. The cells of this bacterium were introduced into the coelomic cavity of another echinoderm, the sea urchin Strongylocentrotus nudus. As a result, in about 24h the animals became slow and 3-8days after the inoculation died. Dividing bacteria were being found during the experiment in the coelomic fluid as well as in the phagosomes of amoebocytes, i.e. cells acting as phagocytes in the coelomic fluid. The studies of the invasive properties of strain 156 showed that bacterial cells entered the subcuticular space of S. nudus and A. japonicus through the cuticle and stayed there for a long time without penetrating epithelium and exerting toxic effect upon the organisms of the laboratory animals. Pathogenic effect of S. algae can be manifested only if the cutaneous epithelium is destroyed permitting it to penetrate the lower tissue layers. The toxicity of S. algae is confirmed by in vitro experiments. The inoculation of the embryonic cells of S. nudus with samples of this bacterium caused the death of 10% of cells within an hour and 100% of cells within 12h after inoculation. The results of the investigations demonstrate that S. algae could produce opportunistic infection in the sea cucumber A. japonicus and the sea urchin S. nudus, which may be natural reservoirs of this human pathogen.

Fulvivirga kasyanovii gen. nov., sp. nov., a novel member of the phylum Bacteroidetes isolated from seawater in a mussel farm.

A novel, strictly aerobic, heterotrophic, gliding, Gram-negative, oxidase-, catalase-, beta-galactosidase- and alkaline phosphatase-positive marine bacterium, designated strain KMM 6220(T), was isolated from seawater and studied by using a polyphasic taxonomic approach. The DNA G+C content of strain KMM 6220(T) was 59.9 mol%. The predominant fatty acids were iso-C(15 : 1), iso-C(15 : 0), iso-C(15 : 0) 3-OH, iso-C(17 : 0) 3-OH and C(16 : 1)omega7/iso-C(15 : 0) 2-OH. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that strain KMM 6220(T) formed a cluster with the misclassified strains [Flexibacter] aggregans NBRC 15974 and [Flexibacter] tractuosus NBRC 16035 and with the type strains of Reichenbachiella agariperforans and Roseivirga ehrenbergii with levels of similarity of 95.9, 94.4, 92.0 and 91.8 %, respectively. On the basis of its phenotypic, chemotaxonomic, genotypic and phylogenetic characteristics, strain KMM 6220(T) is considered to represent a novel species of a new genus in the phylum Bacteroidetes, for which the name Fulvivirga kasyanovii gen. nov., sp. nov. is proposed. The type strain of the type species is KMM 6220(T) (=CCTCC AB 206119(T)=KCTC 12832(T)).

Echinicola vietnamensis sp. nov., a member of the phylum Bacteroidetes isolated from seawater.

The taxonomic position of a novel marine, heterotrophic, gliding, halotolerant and light-pink-pigmented bacterium, designated strain KMM 6221(T), was examined by using a polyphasic approach. 16S rRNA gene sequence analysis indicated that strain KMM 6221(T) is affiliated with the genus Echinicola, a member of the phylum Bacteroidetes, with levels of similarity of 94.7-95.0 % to strains of Echinicola pacifica. Growth of strain KMM 6221(T) was observed with 0-15 % NaCl and at 6-44 degrees C. The DNA G+C content of strain KMM 6221(T) was 45.9 mol%. On the basis of molecular distinctiveness supported by phenotypic and chemotaxonomic data, strain KMM 6221(T) is considered to represent a novel species of the genus Echinicola, for which the name Echinicola vietnamensis sp. nov. is proposed. The type strain is KMM 6221(T) (=DSM 17526(T)=LMG 23754(T)).