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The sea cucumber Holothuria (Theelothuria) notabilis for the first time is reported from the Beibu Gulf, South China Sea. A morphological description of this new record with colour figures and scanning electron microcopy images of its ossicles are provided. This finding widens the geographical range of H. (T.) notabilis and indicates that this species may expand northwards in the South China Sea. With our new record, the subgenus theelothuria is now represented by three species in China. [ABSTRACT FROM PUBLISHER]

Abstract: A species-specific PCR (polymerase chain reaction) method was developed to identify the 11 sea cucumber species, even in highly processed food samples such as frozen or dried sea cucumbers (beche-de-mer). Universal primers were used for the amplification of 16S rRNA gene in each species. The alignment of the obtained sequences was the basis for the design of 11 species-specific reverse primers located in the 16S rRNA gene region. The developed species-specific PCR method was successfully applied to authenticate species of commercial sea cucumber products. Therefore, this method really provides a simple, fast and reliable protocol for the accurate identification of sea cucumber species, and also can be very useful for correct labeling of commercial products, traceability, and protection of the consumer''s rights. [Copyright &y& Elsevier]

The complete sequence of mitochondrial DNA (mt DNA) from Stichopus sp. (Echinodermata: Holothuroidea: Stichopodidae: Stichopus) was acquired using conventional PCR and long PCR followed by cloning and sequencing. The mt DNA is a circular molecule of 16 257 bp in length, containing the set of 37 genes, including 13 protein-coding genes ( PCGs), 22 t RNA genes and two ribosomal RNA genes. The plus strand consists of 30.9% A, 23.7% C, 16.0% G and 29.3% T bases (AT skew = 0.027; GC skew = −0.194). All 13 PCGs encode a total of 3782 amino acids and all 22 t RNA genes were predicted to be capable of folding into a clover-leaf secondary structure. Intergenetic regions in the mitochondrial genome of Stichopus sp. contain 903 bp in total, with the largest continuous region (674 bp, AT% = 58.6) between t RNA-Thr and t RNA-Pro. Analysis of phylogenetic relationship of family Stichopodidae and genetic distances (species among the family Stichopodidae and species within Stichopus monotuberculatus group) based on the partial cox1 sequence demonstrates that Stichopus sp. from the South China Sea is a member of S. monotuberculatus complex. [ABSTRACT FROM AUTHOR]

Abstract: Sea cucumbers are regarded as traditional delicacies, medicine and aphrodisiacs in Asia over many centuries. Generally, sea cucumbers are gutted, boiled and roasted, then preserved through drying, smoking or freezing. Thus, it is very difficult to identify clearly the species of processed sea cucumber on the basis of their morphology. In this work, FINS methodology was developed as a tool to assess the incidence of incorrect labeling of sea cucumbers belonging to family Holothuriidae in commercial food products. The result showed that 7 samples were incorrectly labeled (63.6%). Moreover, the technique allows the genetic identification of more than 40 species from all over the world. [ABSTRACT FROM AUTHOR]

Abstract: Sea cucumbers are traditional, delicious and luxurious seafood in Asia. They are usually provided to the consumers in the marketing formats of dried or frozen products. At the commercial level, they are much different not only in flavor, but also in price. The processing treatment makes them difficult for species identification based on morphological characterization. In this study, two molecular methods are developed to identify six species belonging to family Stichopodidae in commercial products. The first one is PCR–RFLP (polymerase chain reaction–restriction fragment length polymorphism), which uses PCR amplification of a common 570bp fragment of the 16S rRNA gene and follows codigestion with two restriction enzymes (XmnI and MwoI). Another one is FINS (forensically informative nucleotide sequencing) of the 16S rRNA gene, and the key of the method is the phylogenetic analysis of 16S rRNA gene sequences. The PCR–RFLP methodology can be used to authenticate the species tested in the present study and allow us to detect a fraudulent labeling of frozen Apostichopus japonicus product. And the FINS methodology confirms that the species substituted for A. japonicus belongs to the genera Isostichopus. Therefore, two molecular tools really provide convenient, useful and academic techniques to authenticate the species of commercial sea cucumber products. [Copyright &y& Elsevier]

Vitellogenesis is the process of yolk formation via accumulating vitellin (Vn) with nutrients in the oocytes. Expression of vitellogenin (Vg), the precursor of Vn, is one of the indicators for the start of vitellogenesis. In Pacific white shrimp (Litopenaeus vannamei), the type-II vitellogenesis-inhibiting hormone (VIH-2) effectively suppresses hepatopancreatic Vg mRNA expression. In this study, we demonstrate the increasing transcript levels of hepatopancreatic Vg during L. vannamei ovarian development, suggesting that the hepatopancreas-derived Vg/Vn may also contribute to vitellogenesis in this species. Using a combination of in vivo injections and in vitro primary cell cultures, we provide evidences that the inhibition of VIH-2 on hepatopancreatic Vg gene expression is mediated through a functional coupling of the GC/cGMP pathway with different MAPK-dependent cascades in female shrimp. In VIH-2 signaling, the NO-independent GC/cGMP/PKG cascades were upstream of the MAPKs. Activations of the MAPK signal by VIH-2 include the phosphorylation of JNK and the mRNA/protein expression of P38MAPK. Additionally, the cAMP/PKA pathway is another positive intracellular signal for hepatopancreatic Vg mRNA expression but is independent of its VIH-2 regulation. Our findings establish a model for the signal transduction mechanism of Vg regulation by VIH and shed light on the biological functions and signaling of the CHH family in crustaceans. [ABSTRACT FROM AUTHOR]

Osmoregulation is one of the most fundamental and delicately controlled processes in euryhaline marine species like penaeid shrimp. Here we first report a cDNA encoding for the crustacean cardioactive peptide (CCAP) precursor cloned from the intestine of Pacific white shrimp, Litopenaeus vannamei , a prominent commercial culture species. The CCAP mature peptide (PFCNAFTGC-NH 2 ) is generated by post-translational processing and found to be highly comparable with its counterparts in insects and other crustaceans. Semi-quantitative RT-PCR reveals that L. vannamei CCAP ( Lv-CCAP ) mRNA is predominantly expressed in the brain and intestine. However, only the expression level of intestine-derived Lv-CCAP mRNA showed responsiveness to salinity changes in culture. The inducible expressed Lv-CCAP mRNA by transfer to high-salinity condition was continuous, while mRNA expression stimulated by transfer to low-salinity condition was transient. Functionally, the stimulatory effects of CCAP on heart rates in the shrimp cultured in low- and normal-salinity conditions were confirmed. Furthermore, injection of CCAP could up-regulate the freshwater tolerance of shrimp by increasing their survival rates. Our study, as a whole, provides new insights into hormone-regulated crustacean osmostasis and may prove instructive to the inland freshwater penaeid shrimp aquaculture. State of relevance It proves instructive to freshwater shrimp aquaculture. [ABSTRACT FROM AUTHOR]

To better understand the adaptive strategies of osmotic and ionic regulation inPenaeus vannamei, a full-length cDNA sequence encoding the Na,K-ATPase alpha subunit was isolated and characterized by rapid amplification of the cDNA ends (RACE). The nucleotide sequence was 3953 bp in length and included a 300 bp 5′ untranslated region (UTR), 536 bp 3′ UTR with an AATAA canonical polyadenylation signal sequence and poly (A) tail, and a 3117 bp open reading frame (ORF) encoding a 1038 amino acid protein. The calculated molecular weight of the protein was 115.4 kDa with an estimated pI of 5.29. This sequence was submitted to the National Center for Biotechnology Information (NCBI) GenBank under accession number KF765670. A phenetic analysis showed that the Na,K-ATPase α-subunit ofP. vannameishared a high degree of identity with other species. The relevant mRNA was detected in all of the tissues examined by fluorescent quantitative real-time polymerase chain reaction. The expression level was higher in the gills and hepatopancreas, and lower in the guts, muscles and epithelia. Increased expression of Na,K-ATPase mRNA levels was observed in all of the tissues examined in response to salinity exposure, and there was a significant difference in the tissues of the gills and hepatopancreas (P< 0.05); however, no statistical difference was observed in the epithelia, guts and muscles compared with the controls (P> 0.05). The findings demonstrated that the Na,K-ATPase α-subunit is highly conserved in crustaceans, and differential expression in different tissues ofP. vannameiwas observed, indicating that the gene might have multiple functions in the shrimp. [ABSTRACT FROM PUBLISHER]

Molt-inhibiting hormone (MIH), a peptide member of the crustacean hyperglycemic hormone (CHH) family, is commonly considered as a negative regulator during the molt cycle in crustaceans. Phylogenetic analysis of CHH family peptides in penaeidae shrimps suggested that there is no significant differentiation between MIH and vitellogenesis-inhibiting hormone (VIH, another peptide member of CHH family), by far the most potent negative regulator of crustacean vitellogenesis known. Thus, MIH may also play a role in regulating vitellogenesis. In this study, two previously reported putative MIHs (LivMIH1 and LivMIH2) in the Pacific white shrimp ( Litopenaeus vannamei ) were expressed in Escherichia coli , purified by immobilized metal ion affinity chromatography (IMAC) and further confirmed by western blot. Regulation of vitellogenin (VTG) mRNA expression by recombinant LivMIH1 and LivMIH2 challenge was performed by both in vitro hepatopancreatic primary cells culture and in vivo injection approaches. In in vitro primary culture of shrimp hepatopancreatic cells, only LivMIH2 but not LivMIH1 administration could improve the mRNA expression of VTG. In in vivo injection experiments, similarly, only LivMIH2 but not LivMIH1 could stimulate hepatopancreatic VTG gene expression and induce ovary maturation. Our study may provide evidence for one isoform of MIH (MIH2 in L. vannamei ) may serve as one of the mediators of the physiological progress of molting and vitellogenesis. Our study may also give new insight in CHH family peptides regulating reproduction in crustaceans, in particular penaeidae shrimps. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is a key effector molecule produced in the innate immune systems of many species for antimicrobial defense. However, how NO production is regulated during bacterial infection in invertebrates, especially crustaceans, remains poorly understood. Vibrio harveyi , a Gram-negative marine pathogen, is among the most prevalent and serious threats to the world's shrimp culture industry. Its virulence typically manifests itself through shrimp hepatopancreas destruction. In the current study, we found that NO generated by an in vitro donor system (NOC-18) could rapidly and effectively kill V. harveyi . In addition, injection of heat-killed V . harveyi increased the concentration of NO/nitrite and the mRNA expression of nitric oxide synthase (NOS) in the hepatopancreas of Pacific white shrimp ( Litopenaeus vannamei ), the commercially most significant shrimp species. Live V . harveyi challenge also induced NO/nitrite production and NOS gene expression in primary L . vannamei hepatopancreatic cells in a time- and dose-dependent manner. Co-incubation of l -NAME, an inhibitor selective for mammalian constitutive NOSs, dose-dependently blocked V. harveyi -induced NO/nitrite production, without affecting V. harveyi -induced NOS mRNA expression. Furthermore, l -NAME treatment significantly increased the survival rate of infecting V. harveyi in cultured primary hepatopancreatic cells of L . vannamei . As a whole, we have demonstrated that endogenous NO produced by L . vannamei hepatopancreatic cells occurs in enzymatically regulated manners and is sufficient to act as a bactericidal molecule for V . harveyi clearance. [ABSTRACT FROM AUTHOR]

Tropical commercial sea cucumber Stichopus horrens is extensively distributed throughout the tropical Indo-Pacific region, and wild stocks are severely depleted over the past decade. This study firstly presented preliminary results on the spawning, the development of larvae and the growth of the juvenile of S. horrens in Xisha Islands. It was proved that S. horrens followed a predictable lunar spawning periodicity and might reproduce throughout the year in Xisha Islands. Dry stimulation was a simple and efficient way to induce S. horrens to spawn. The mean quantity of spawned eggs was 1.37×106 (s.e.=2.09×106, n=8), and the mean egg diameter was 114μm (s.e.=2.8μm, n=8). S. horrens developed from fertilized eggs to pentactula larval after 19–27days at 25–27°C. From oosperm to settled juvenile, the survival rate of S. horrens was 1.0%–6.83% when enough live microalgae were supplied. The mean growth rate of juveniles was 0.4mm per day and the survival rate was about 23.3%–50.5% during 80days culture after settlement. Then some juveniles of S. horrens were further cultivated in tanks and majority were released in the wild. Ongoing observations showed good survival and growth of juvenile in the wild. The study indicates S. horrens are amenable to culture using standard techniques which may also be applied on the culture of other tropical species. They exhibit a relatively quick growth both in indoor and wild culture. Furthermore, the test results support possible aquaculture and stock restoration using hatchery produced stocks. [ABSTRACT FROM AUTHOR]

Abstract: The global populations of Curry fish have been severely depleted over the past decade. This study describes spawning, fertilization, larval rearing, and juvenile growth in a commercially important Stichopus species. Data pooled from monthly trials conducted over 2years indicate that, under optimal conditions, juveniles can be grown to a size of ca. 20cm in length in 7months. The survival rates are typically between 30 and 50%. Pilot research indicates that the growth of young sea cucumbers in abandoned abalone tanks has potential. Overall, this study demonstrates that Curry fish can be reared in captivity, thus providing an alternative to fisheries, or a way to maintain sustainable harvests and eventually contribute to the restoration of the natural populations. [Copyright &y& Elsevier]