Transcriptome survey of phototransduction and clock genes in marine bivalves.

Marine animals exhibit a variety of biological rhythms, such as solar and lunar-related cycles; however, our current molecular understanding of biological rhythms in marine animals is quite limited. Identifying and understanding the expression patterns of clock genes from available transcriptomes will help elucidate biological rhythms in marine species. Here, we perform a comprehensive survey of phototransduction and circadian genes using the mantle transcriptome of the scallop Patinopecten yessoensis and compare the results with those from three other bivalves. The comparison reveals the presence of transcripts for most of the core members of the phototransduction and circadian networks seen in terrestrial model species in the four marine bivalves. Matches were found for all 37 queried genes, and the expressed transcripts from the deep sequencing data matched 8 key insect and mammalian circadian genes. This demonstrates the high level of conservation of the timekeeping mechanism from terrestrial species to marine bivalves. The results provide a valuable gene resource for studies of "marine rhythms" and also further our understanding of the diversification and evolution of rhythms in marine species.

Investigations on the genomic diversity of OXA from isolated Acinetobacter baumannii.

We distinguished the four OXA-type carbapenemase subgroup alleles present in 120 strains of Acinetobacter baumannii by using polymerase chain reaction (PCR) and investigated the distributions of the OXA subgroups in clinically isolated samples. Amplification of the OXA genes blaOXA-23, blaOXA-24, blaOXA-51, and blaOXA-58 was performed by multiplex PCR. Antibiotics susceptibility test was conducted for determine the sensitivity of the A. baumannii to clinical common used antibiotics by Kirby-Bauer method. Results revealed that 46 (51.69%) of the samples were positive for only the blaOXA51 gene and 41 (46.07%) were positive for both the blaOXA51 and blaOXA58 genes in the 89 isolates of A. baumannii. Among these, 45 were carbapenem-resistant and 44 carbapenem-sensitive. Strains containing either blaOXA51 or blaOXA58 showed resistance or sensitivity to carbapenems, respectively. A. baumannii isolated from intensive care units showed significantly higher resistance rate to Cefepime, Piperacillin-tazobactam, Amikacin, Ceftazidime, Cefotaxime, Sulfamethoxazole-trimethoprim, and Gentamicin than those isolated from other departments (P < 0.05). In conclusion, we found that the presence of blaOXA-51 and blaOXA-58 appears to convey a mechanism of resistance or sensitivity to carbapenems, respectively, in A. baumannii clinical isolates.

Novel polymorphic microsatellite markers isolated from the pen shell Atrina pectinata (Mollusca: Bivalvia: Pinnidae).

In this study, we isolated 21 novel polymorphic microsatellite DNA loci from the pen shell Atrina pectinata using magnetic-bead hybridization enrichment. The characteristics of these loci were tested using a population of 30 individuals collected from the Penglai coast, Shandong Province. The number of alleles ranged from 2 to 13, and polymorphism information content (PIC) varied from 0.1730 to 0.8954. Values for observed heterozygosity (HO) and expected heterozygosity (HE) ranged from 0.0714 to 0.9231 and from 0.1948 to 0.9237, respectively. Four loci deviated significantly from Hardy-Weinberg equilibrium. The newly developed microsatellite markers will be beneficial in assessing the genetic diversity, population structure and genetic conservation of A. pectinata, and in other relevant research.

Isolation and characterization of 48 polymorphic microsatellite markers for the blood clam Scapharca broughtonii (Arcidae).

Blood clams (Scapharca broughtonii) are widely cultivated and consumed in noutheast Asia. Forty-eight polymorphic microsatellite loci were developed for this clam using magnetic-bead hybridization enrichment. The number of alleles per locus ranged from 2 to 14. Polymorphism of these loci was assessed in 30 individuals from a population collected from coastal areas of Qingdao, China. The values of observed heterozygosity, expected heterozygosity and polymorphism information content per locus ranged from 0.1034 to 0.9655, from 0.1831 to 0.9208, and from 0.1638 to 0.8964, respectively. Forty-three of 48 loci conformed to Hardy-Weinberg equilibrium. These microsatellite loci would be useful for molecular genetic breeding, population genetics, genome mapping, and other relevant research on S. broughtonii.