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In the present study, the tissue-specific and temporal gene expression profiles of four catalogues of gonadal development-related genes (sex differentiation-related, steroid receptor, steroidogenic, and structural genes) were detected in nine tissues and during 11 successive developmental stages in the Pengze crucian carp (Pcc) (a triploid mono-female gynogenic fish). The results showed that these target genes exhibited overlapping distributions in various tissues, with the exception of Pcc-vasa and Pcc-cyp17a1. Gene expression profiling of the developmental stages showed that all of the target genes simultaneously reached peak expression levels at 40 and 48 days post hatching (dph). Both 40 and 48 dph appeared to be two key time points associated with the process of Pcc gonadal development. These data will provide a clear understanding of gene expression patterns associated with the gonadal development-related genes of this gynogenic teleost.

Studies were conducted to determine the cause of high mortalities of cultured half-smooth tongue sole Cynoglossus semilaevis. Gross signs of disease included loss of appetite, erratic swimming, and haemorrhages on the head, opercula and base of fins, dorsal fin rot, swollen abdomen filled with ascitic fluid and herniation of the intestine. Histological examination of the liver showed focal areas of necrosis and extensive haemorrhages. Virtually pure, dense bacterial cultures were obtained from liver, kidney and spleen tissues, and high pathogenicity of the isolates to tongue sole was confirmed. The phenotypic characteristics of the isolates including morphological, physiological and biochemical characteristics were determined. The 16S rRNA and gyrB genes of the isolates were sequenced, and the phylogenetic trees representing genetic relatedness between the isolate and publicly available 16S rRNA and gyrB gene sequences from GenBank were constructed. The results confirmed that the diseased tongue soles were infected with Vibrio aestuarianus. The sequenced 16S rRNA gene of strain TS1 (GenBank Accession No. GQ372983) was 1446bp, the gyrB gene of strain TS1 (GenBank Accession No. GQ372984) was 1200bp and the two genes exhibited high similarity (98~99%) to those of V. aestuarianus from GenBank. In addition, the activities of extracellular enzymes and haemolysin were also studied; the results showed that the isolates produced beta haemolysis on rabbit blood agar, lecithinase, proteinase, DNase and lipase, but gelatinase was not produced., (© 2010 Blackwell Publishing Ltd.)