Yanhong Wang

Molecular characterization of metallothionein from white shrimp, Litopenaeus vannamei and its expression response to salinity stress

Abstract The metallothioneins (MTs) are conserved and multi-functional proteins which play crucial roles in the transportation of essential trace elements and the detoxification of harmful metallic elements. A novel MT homologue (accession no. JN707684) was isolated from the Litopenaeus vannamei hypersalinity subtractive library and used to carry out tissue-specific expression under varying salinity stress. The complete cDNA sequence of LvMT contains a 177 bp open reading frame encoding 58 amino acids, a 66 bp 5′-UTR, and a 117 bp 3′-UTR. The LvMT was expressed in the highest peak in the hepatopancreas under hyposalinity (3 g l−1) (19.43-fold, p < 0.01) and hypersalinity (40 g l−1) (22.3-fold, p < 0.01) stress for 6 h. A phylogenetic analysis revealed that LvMT is similar to other crustacean MT proteins. The LvMT was distributed in both the cytoplasm and the nucleus of HeLa and EPC cells.

The genetic diversity of the noble scallop (Chlamys nobilis, Reeve 1852) in China assessed using five microsatellite markers.

Five highly variable microsatellite loci were used to investigate the genetic diversity and population structure of the noble scallop Chlamys nobilis, in the South China Sea. A total of 200 individual scallops from 4 populations were genotyped. All of the 5 microsatellite loci screened in this study showed polymorphism. A total of 32 different alleles were observed over all loci. The number of alleles per locus ranged from 3 to 12. The average allelic number of these polymorphic markers was 6.4. The averages of observed (Ho) and expected heterozygosity (He) ranged from 0.07 to 0.32 and from 0.119 to 0.459, respectively. A highly significant deviation from the Hardy-Weinberg Law, owing primarily to heterozygote deficiency, was found in all populations studied. The Nanao population exhibited more genetic diversity than the other three populations in terms of allele richness and observed and expected heterozygosity.

Transcriptomic analyses on muscle tissues of Litopenaeus vannamei provide the first profile insight into the response to low temperature stress

The Pacific white shrimp (Litopenaeus vannamei) is an important cultured crustacean species worldwide. However, little is known about the molecular mechanism of this species involved in the response to cold stress. In this study, four separate RNA-Seq libraries of L. vannamei were generated from 13°C stress and control temperature. Total 29,662 of Unigenes and overall of 19,619 annotated genes were obtained. Three comparisons were carried out among the four libraries, in which 72 of the top 20% of differentially-expressed genes were obtained, 15 GO and 5 KEGG temperature-sensitive pathways were fished out. Catalytic activity (GO: 0003824) and Metabolic pathways (ko01100) were the most annotated GO and KEGG pathways in response to cold stress, respectively. In addition, Calcium, MAPK cascade, Transcription factor and Serine/threonine-protein kinase signal pathway were picked out and clustered. Serine/threonine-protein kinase signal pathway might play more important roles in cold adaptation, while other three signal pathway were not widely transcribed. Our results had summarized the differentially-expressed genes and suggested the major important signaling pathways and related genes. These findings provide the first profile insight into the molecular basis of L. vannamei response to cold stress.

A preliminary study on microsatellite markers screening from EST sequences of Litopenaeus vannamei : A preliminary study on microsatellite markers screening from EST sequences of Litopenaeus vannamei

EST-SSR marker development by screening and mining the SSR repeats in the EST database of Litopenaeus vannamei,161 075 EST sequences were downloaded from EST sequences in the database of GenBank.EST sequences were analyzed and the SSR was screened with SSIRT(http:∥www.gramene.org/db/markers.ssrtoo).As a result,12 600(7.8%)SSRs were identified from the EST resources,among which there were 10 104(80.2%)dinucleotide,2 036(16.1%)trinucleotide,336(2.7%)tetranucleotide,35(0.3%)pentanucleotide and 89(0.7%)hexanucleode SSRs.Among the dinucleotide sequences,AG/CT repeat motif accounted for 4 820(47.8%),3 584(35.4%)AC/GT repeat motif,AT/TA,CG/GC repeat motif was 1 673(6.6%),27(0.2%)respectively.77 pairs of primers were designed with Primer Premier 5.0.Fifty four primer pairs obtained expected product,with the success rate of 70.1%.And 28 of them showed polymorphism among 10 individuals,polymorphism rate was 51.9%.Number of alleles ranged from 2 to 5,and PCR product size was 140-600 bp.This implies that the polymorphism EST-SSR developed from NCBI could work in genetic mapping,gene clone and gene functional research.