ATP-gated P2X7 receptor (P2RX7) channel is a key component for purinergic signaling and plays important roles in the innate immune response in mammals. However, the expression, molecular properties and immune significances of P2RX7 in lower vertebrates are still very limited. Here we identified and characterized a novel bony fish P2RX7 homologue cDNA, termed poP2RX7, in Japanese flounder (Paralichthys olivaceus). PoP2RX7 protein shares about 60–88% sequence similarity and 45–78% sequence identity with known vertebrate P2RX7 proteins. Phylogenetic analysis placed poP2RX7 and other P2RX7 proteins within their own cluster apart from other P2RX members. While the functional poP2RX7 channel shares structural features in common with known P2RX7 homologs, electrophysiological studies revealed that BzATP, the more potent agonist for known mammalian and fish P2RX7s, shows similar potency to ATP in poP2RX7 activation. poP2RX7 mRNA constitutively expressed in all examined tissues from unstimulated healthy Japanese flounder with dominant expression in hepatopancreas and the lowest expression in head kidney, trunk kidney, spleen and gill. poP2RX7 mRNA expression, however, was significantly induced in Japanese flounder head kidney primary cells by Poly(I:C) and bacterial endotoxin LPS stimulations. In vivo experiments further revealed that poP2RX7 gene expression was substantially up-regulated by immune challenge with infectious bacteria Edwardsiella tarda and Vibrio anguillarum. Moreover, activation of poP2RX7 results in an increased gene expression of multifunctional cytokines IL-1β and IL-6 in the head kidney primary cells. Collectively, we identified and characterized a novel fish P2RX7 homolog which is engaged in Japanese flounder innate immune response probably through modulation of pro-inflammatory cytokines expression.

The new secondary metabolites verrucosidinol (1) and its derivative verrucosidinol acetate (2), together with a potent neurotoxin verrucosidin (3), a congener norverrucosidin (4) and a mixture of two known phytotoxic metabolites terrestric acids (5 and 6), were isolated from the marine derived fungus Penicillium aurantiogriseum. Verrucosidinol has a ring-opened ethylene oxide moiety in the polyene α-pyrone skeleton, and verrucosidinol acetate is its acetate derivative. The chemical structures were determined by comparing with literature data and a combination of spectroscopic techniques, including high resolution mass spectrum and two-dimentional nuclear magnetic resonance spectroscopic analysis.

No abstract

No abstract

Information about seasonal bacterial composition and diversity is of great value for exploitation of marine biological resources and improvement of ecological environment. Here PCR-amplified restriction fragment length polymorphism (PCR-RFLP) of 16S rRNA genes was used to evaluate seasonal bacterial diversity and community composition in Bohai Bay. A total of 24 bacterial communities were sampled from seawater and sediment of three representative sites in a whole seasonal cycle: spring (April), summer (July), autumn (October), and winter (January). Bacterial Genomic DNA was extracted and PCR-amplified to obtain 16S rDNA fragments which were cloned to construct 24 16s rDNA libraries. Clones of each library were selected randomly for PCR-RFLP analysis of rDNA fragments, and eventually 101 genotypes were identified by RFLP fingerprintings. These 101 genotypes were sequenced and their respective phylotype was identified through the Blast tool of NCBI (similarity 96-100%) and phylogenetic analyses. Among our phylotypes, 80.2% belonged to the genera a-Proteobacteria, b-proteobacteria,c-Proteobacteria, d-Proteobacteria, e-proteobacteria, Flavobacteria, Cytophaga-Flavobacteria-Bacteroides, Verrucomicrobia, Firmicutes and Actinobacteria. Sequence analyses revealed that 47.5% (48) of clone sequences were similar to those of uncultured marine bacteria in the environment. In addition, bacterial diversity and composition clearly displayed seasonal variety. More genera were discovered in summer than any other seasons, and some special species appeared only in specific season.