Winogradskyella luteola sp.nov., Erythrobacter ani sp. nov., and Erythrobacter crassostrea sp.nov., isolated from the hemolymph of the Pacific Oyster Crassostrea gigas.

Three new bacterial strains, WHY3T, WH131T, and WH158T, were isolated and described from the hemolymph of the Pacific oyster Crassostrea gigas utilizing polyphasic taxonomic techniques. The 16S rRNA gene sequence analysis revealed that strain WHY3T was a member of the genus Winogradskyella, whereas strains WHI31T and WH158T were members of the genus Erythrobacter. According to the polygenomic study the three strains formed individual lineages with strong bootstrap support. The comparison of dDDH-and ANI values, percentage of conserved proteins (POCP), and average amino acid identity (AAl) between the three strains and their relatives established that the three strains represented two separate genera. Menaquinone-6 was reported as the major respiratory quinone in strain WHY3T and Ubiquinone-10 for strains WH131T and WH158T, respectively. The major cellular fatty acids for strain WHY3T were C15:0, anteiso-C15:1 ω7c, iso-C15:0, C16:1ω7c. The major cellular fatty acids for strains WH131T and WH158T were C14:02-OH and t18:1ω12 for WH131T and C17:0, and C18:1ω7c for strain WH158T. Positive Sudan Black B staining Indicated the presence of polyhydroxyalkanoic acid granules for strains WH131T and WH158T but not for strain WHY3T. The DNA G + C contents of strains WHY3T, WH131T and WH158T were 34.4, 59.7 and 56.6%, respectively. Gene clusters predicted some important genes involved in the bioremediation process. Due to the accomplishment of polyphasic taxonomy, we propose three novel species Winogradskyella luteola sp.nov. (type strain WHY3T = DSM 111804T = NCCB 100833T), Erythrobacter ani sp.nov. (WH131T = DSM 112099T = NCCB 100824T) and Erythrobacter crassostrea sp.nov. (WH158T = DSM 112102T = NCCB 100877T).

Photobacterium arenosum WH24, Isolated from the Gill of Pacific Oyster Crassostrea gigas from the North Sea of Germany: Co-cultivation and Prediction of Virulence.

Cream colored bacteria from marine agar, strain WH24, WH77, and WH80 were isolated from the gill of the Crassostrea gigas a Pacific oyster with a filter-feeding habit that compels accompanying bacteria to demonstrate a high metabolic capacity, has proven able to colonize locations with changing circumstances. Based on the 16S rRNA gene sequence, all strains had high similarity to Photobacterium arenosum CAU 1568T (99.72%). This study involved phenotypic traits, phylogenetic analysis, antimicrobial activity evaluation, genome mining, Co-cultivation experiments, and chemical studies of crude extracts using HPLC and LC-HRESIMS. Photobacterium arenosum WH24 and Zooshikella harenae WH53Twere co-cultivated for 3 days in a rotary shaker at 160 rpm at 30 °C, and LC-MS monitored the chemical profiles of the co-cultures on the third day. The UV chromatograms of the extracts of the co-cultivation experiments show that Zooshikella harenae WH53T could be inhibited by strain WH24. The high virulence of Photobacterium arenosum WH24 was confirmed by genome analysis. Gene groups with high virulence potential were detected: tssA (ImpA), tssB (ImpB/vipA), tssC (ImpC/vipB), tssE, tssF (ImpG/vasA), tssG (ImpH/vasB), tssM (IcmF/vasK), tssJ (vasD), tssK (ImpJ/vasE), tssL (ImpK/vasF), clpV (tssH), vasH, hcp, lapP, plpD, and tpsB family.

Antimicrobial potential of culturable actinobacteria isolated from the Pacific oyster Crassostrea gigas (Bivalvia, Ostreidae).

AIMS: Explore the diversity of culturable actinobacteria isolated from the Pacific oyster Crassostrea gigas with special emphasis on their antimicrobial activity. METHODS AND RESULTS: For the characterization of the isolated actinobacteria, a polyphasic approach was adopted and thereby phenotypic descriptions, phylogenetic analysis, evaluations of antimicrobial activities and chemical analyses of crude extracts through HPLC and LC-HRESIMS were performed. Five strains were isolated from C. gigas. The 16S rRNA gene analysis revealed that three of them were taxonomically affiliated to the genus Streptomyces and the other two strains were related to Micromonospora. High inhibition was detected against different test microorganisms such as Candida albicans, Staphylococcus aureus, Bacillus subtilis and Mycobacterium smegmatis. On the basis of the chemical analysis, 11 compounds from the active fractions of the crude extracts were determined, and 8 were related putatively to previously reported compounds. CONCLUSIONS: Actinobacteria isolated from C. gigas represent an interesting reservoir of antimicrobial compounds, and further study to uncover the full capacity of this source is encouraged. SIGNIFICANCE AND IMPACT: At present, the study of actinobacteria and their antimicrobial potential from uncommon sources as C. gigas is vital to the development of new therapeutic agents to cope with the widespread resistance of human pathogens.