Effect of <Emphasis Type="Italic">Codonopsis pilosula</Emphasis> on Immune and Digestion in Sea Cucumber, <Emphasis Type="Italic">Apostichopus japonicus</Emphasis>

A 8-week trial was conducted to evaluate the effect of Codonopsis pilosula on immune and digestion in sea cucumber. The results showed that the total coelomocytes counts (TCC), phagocytic activity and superoxide anion production (O₂^-), superoxide dismutase (SOD), acid phosphatase (ACP), phenoloxidase (PO) activities in coelomocytes of sea cucumbers were improved significantly after 28 or 42 days. Again dietary C. pilosula had a positive impact by activating the RNA expression levels of complement component 3 (C3), lysozyme and protease, amylase and alginase activities in the gut. Finally the resistance of A. japonicus against Vibrio splendidus was enhanced.     

Changes in Body Wall of Sea Cucumber (<Emphasis Type="Italic">Stichopus japonicus</Emphasis>) during a two-Step Heating Process Assessed by Rheology,LF-NMR,and Texture Profile Analysis

Sea cucumber (Stichopus japonicus) is regarded as a highly priced delicacy in Japan and China owing to its unique elasticity and palatability. Heating is an essential step to process sea cucumber with desired texture. In the present study, sea cucumber body wall was pre-heated at 40 °C, followed by post-heating at 80 °C. Changes in body wall were assessed by rheology, LF-NMR, and texture profile analysis. The small strain rheological analysis indicated that there were significant structural changes of body wall at about 40 °C during pre-heating. Large strain texture profile analysis and the storage modulus showed a good correlation. LF-NMR analysis displayed only one water population in samples pre-heated at 40 °C for up to 120 min, and the population did not change significantly with the heating duration. This demonstrated that structural changes and moisture loss from the inter collagen fibrils were not significant. As for samples post-heated at 80 °C, three distinct peaks were found and the T ₂ relaxation time and area of the bulk water decreased significantly, revealing significant changes of internal structures and loss of water-holding capacity. T ₂ parameters had a good correlation to texture profile analysis parameters for samples after both pre-heating and post-heating.     

The Current Status of Populations of the Sea Cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis> (Selenka, 1867) in the Far Eastern Marine Reserve

The spatial distribution of the sea cucumber Apostichopus japonicus (Selenka, 1867) in the Far Eastern Marine Reserve was studied using scuba. The abundance, size composition, population density, and distribution of A. japonicus were determined. The population density of this species at the mainland coast was higher than in waters around islands in the reserve. Seasonal movements of sea cucumber were observed: in autumn large individuals migrate to greater depths, but at the beginning of summer they move to shallow water. The average sizes of individuals and population density of sea cucumber in the reserve do not differ from those in unprotected areas of Peter the Great Bay. A comparative analysis of our own and literature data showed that the current estimates of sea cucumber population density in the reserve are 5?7 times lower than estimates for the period before the illegal fishing of sea cucumber began in Primorye.     

Genome-Wide Identification of the Dicer-Like,Argonaute, and RNA-Dependent RNA Polymerase Gene Families in Cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.)

Dicer, Argonaute (AGO), and RNA-dependent RNA polymerase (RDR) comprise the core components of RNA-induced silencing complexes, which trigger RNA silencing. Here, we performed a complete analysis of the cucumber Dicer-like, AGO, and RDR gene families including the gene structure, genomic localization, and phylogenetic relationships among family members. We identified seven CsAGO genes, five CsDCL genes, and eight CsRDR genes in cucumber. Based on phylogenetic analysis, each of these genes families was categorized into three or four clades. The orthologs of CsAGOs, CsDCLs, and CsRDRs were identified in apple, peach, wild strawberry, foxtail millet, and maize, and the evolutionary relationships among the orthologous gene pairs were investigated. We also investigated the expression levels of CsAGOs, CsDCLs, and CsRDRs in various cucumber tissues. All CsAGOs were relatively higher upregulated in leaves and tendrils than in other organs, especially CsAGO1c, CsAGO1d, and CsAGO7. All CsDCL genes were relatively higher upregulated in tendrils, with almost no expression detected for CsDCL1, CsDCL4a, or CsDCL4b in other organs. In addition, CsRDR1a, CsRDR2, CsRDR3, and CsRDR6 had relatively higher upregulation in tendrils, whereas almost all CsRDRs were downregulation in other organs. The results of this study will facilitate further studies of gene silencing pathways in cucumber.     

The distribution of macrobenthic epifauna in the Far Eastern Marine Reserve based on remote underwater video data

The spatial distribution of epifauna in the Far Eastern Marine Reserve was examined using a remotely operated vehicle. The abundance and distribution patterns of the sea stars Patiria pectinifera, Distolasterias nipon, and Asterias amurensis, as well as those of brittle stars, the black sea cucumber Cucumaria japonica, the sea urchin Strongylocentrotus intermedius, the ascidian Halocynthia aurantium, hermit crabs, and the Japanese scallop Mizuhopecten yessoensis were determined in the South Section of the Reserve. The average biomass of five dominant epifaunal species ranged from 51.0 to 87.4% of the average biomass of the softbottom communities.