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Abstract Response surface methodology coupled with a Box-Behnken design (RSM-BBD) was used to optimize neutrase concentration (A: 4–6% (w/w)), liquid-solid ratio (B: 10–20 mL/g) and hydrolysis time (C: 3–5 h) to obtain shrimp shell wastes hydrolysates with α-amylase inhibitory activity. The optimum conditions were enzyme concentration of 5.4% (w/w), liquid-solid ratio of 13 mL/g, time of 4.1 h, temperature of 50 °C and pH of 7.0. Under these conditions, the α-amylase inhibitory rate was 43.4%, in agreement with the prediction model with a coefficient of determination (R2) of 0.9676. Shrimp shell wastes hydrolysates showed significant ability to scavenge diphenyl picryl hydrazinyl free radicals, reduce iron (III) and inhibit lipid peroxidation. Shrimp shell waste hydrolysates consisted mainly of small peptides with molecular weights less than 4 kDa and high essential amino acids (278 mg/g), which indicated its high nutritional value based on the FAO/WHO recommended standard protein. The results showed that shrimp shell waste hydrolysates contained valuable components that could be converted into useful and potentially high-value products. Graphical abstract fx1 Highlights • A Box-Behnken Design (BBD) was used to obtain shrimp shell waste hydrolysates (SSWH) with α-amylase inhibitory activity. • Optimal conditions occurred at neutrase concentration of 5.4% (w/w), liquid-solid ratio of 13 mg/mL and time of 4.1 h. • SSWH may be used as a nutritional food resource with α-amylase inhibition activity and high essential amino acids. [ABSTRACT FROM AUTHOR]

Abstract: The ovary of triploid shrimp Fenneropenaeus chinensis was apparently impaired compared to that of the diploid shrimp at the same age. Therefore triploid shrimp ovary is possible to be taken as a model to understand the mechanism of ovary development of shrimp compared to that of the ovary of diploid shrimp at the same age. In the present study, a suppression subtractive hybridization (SSH) technique was applied to identify differentially expressed genes in the ovary between diploid and triploid shrimp. For the forward library (RNA from the ovary of triploid shrimp as the tester), 54 genes were identified. For the reverse library (RNA from the ovary of diploid shrimp as the tester), 16 genes were identified. The identified genes encoded proteins with multiple functions, including extracellular matrix components, cytoskeleton, cell growth and death, metabolism, genetic information processing, signal transduction/transport or immunity related proteins. Eleven differentially expressed genes were selected to be confirmed in the ovaries of triploid and diploid shrimp by semi-quantitative RT-PCR. Genes encoding spermatogonial stem-cell renewal factor, cytochrome c oxidase subunits I and II, clottable protein, antimicrobial peptide and transposase showed up-regulated expressions in the ovary of triploid shrimp. Genes encoding tubulin, cellular apoptosis susceptibility protein, farnesoic acid O-methyltransferase, thrombospondin and heat shock protein 90 genes showed higher expressions in the ovary of diploid shrimp. The differential expressions of the above genes are suggested to be related to the ovary development of shrimp. It will provide a new clue to uncover the molecular mechanisms underlying the ovarian development in penaeid shrimp. [Copyright &y& Elsevier]

Cadmium (Cd) is one of the typical metal pollutants in the Bohai Sea. To evaluate the acute toxicological effects of Cd on marine crustaceans, juvenile Fenneropenaeus chinensis and Portunus trituberculatus were exposed to Cd at environmentally relevant concentrations (5 and 50 μg/L) for 96 h. Cd accumulation, antioxidants and metabolite profiles were characterized to elucidate the responses of juvenile crustaceans to Cd stress. Significant Cd accumulation was observed in both juvenile crustaceans in 50 μg/L Cd-treated group. Results showed that Cd exposure induced hormesis based on the alterations of GSH, SOD and CAT activities (i.e. increased levels in the low concentration of Cd treatment and recovered levels in the high concentration of Cd treatment) in juvenile P. trituberculatus. Similarly, the responses of GSH contents presented hormesis pattern in Cd-treated juvenile F. chinensis. Na+-K+-ATPase contents were significantly elevated in 50 μg/L Cd-treated group. In addition, untargeted NMR-based metabolomics indicated Cd caused the disturbance in osmotic regulation and energy consumption in both juvenile F. chinensis and P. trituberculatus via different pathways. The immunotoxicity and movement disorder were uniquely demonstrated in juvenile P. trituberculatus after Cd exposure. [Display omitted] ● GSH, SOD and CAT presented typical hormetic curves in juvenile P. trituberculatus. ● GSH also presented hormesis pattern in juvenile F. chinensis. ● Cd disturbed osmotic regulation and energy consumption in juvenile crustaceans. ● Cd potentially induced immunotoxicity and movement disorder in juvenile crabs. [ABSTRACT FROM AUTHOR]

Abstract: A modified surface spreading technique for synaptonemal complex (SC) analysis was tested to assess the process of chromosome synapsis in spermatocytes of diploid and induced triploid Fenneropenaeus chinensis. Spermatocytes of diploid shrimp showed typical morphological characteristics of eukaryote SC, with complete synapsis of bivalents. No recognizable bivalent associated with sex chromosomes was observed in spermatocytes of diploid shrimp. However, differences in morphology of SC, including unsynapsed univalents, bivalents, totally paired trivalents with non-homologous synapsis, partner switches and triple synapsis were identified at early pachytene stage of triploid spermatocytes. Triple synapsis was especially common at late pachytene stage in spermatocytes of triploid shrimp. The observed abnormal synapsis behavior of chromosomes in spermatocytes indicated that triploid male shrimp may find it difficult to develop normal haploid sperm. [Copyright &y& Elsevier]

Metal pollution in Laizhou Bay along the Bohai Sea in China has been posing a risk on fishery species and hence may affect seafood quality. In this work, shrimps Fenneropenaeus chinensis were sampled from three sites, namely, a reference (site 6334) and two metal-polluted (sites 6262 and 7262) sites, located in Laizhou Bay. The metal concentrations in shrimp muscle tissues were tested using the ICP-MS technique. The Cr and Cu concentrations were the highest in the shrimp samples from site 7262, exceeding the national seafood safety standard Ⅱ, and the As concentration was much higher than the national seafood safety standard Ⅲ. NMR-based metabolomics indicated that metal pollution induced oxidative and immune stresses, damaged the muscular structure, and disrupted energy metabolism in shrimps at sites 6262 and 7262, in particular disturbed osmotic regulation in shrimps at site 7262. Glycine and serine could serve as biomarkers for Cd in F. chinensis. • As in F. chinensis from the middle of Laizhou Bay (S7262) had seafood security risk. • Cr and Cu in F. chinensis from S7262 exceeded national seafood safety standard Ⅱ. • Metal pollution caused oxidative and immune stresses in F. chinensis by metabolomics. • Metal pollution affected various energy metabolism pathways by metabolomics. • Glycine and serine might be used as biomarkers for Cd in shrimp F. chinensis. [ABSTRACT FROM AUTHOR]