Explore the vast range of titles available.

Background Taurine and betaine are important nutrients in the Hong Kong oyster ( Crassostrea hongkongensis ) and have many important biological properties. To investigate the characteristics of taurine and betaine and identify single nucleotide polymorphisms (SNPs) associated with traits in C. hongkongensis , we cloned the full-length cDNA of key genes involved in taurine and betaine metabolism (unpublished data), determined taurine and betaine content and gene expression in different tissues and months of the oyster specimen collection, and developed SNPs in the gene coding region. Results We cloned the full-length cDNA of the genes that express cysteine dioxygenase and cysteine sulfite decarboxylase ( ChCSAD and ChCDO , respectively), which are key genes involved in taurine metabolism in C. hongkongensis , and found that betaine and taurine contents and the expression of key genes were regulated by seawater salinity. A total of 47 SNP markers were developed in the coding regions of ChCSAD , ChCDO , choline dehydrogenase ( ChCDH ), betaine aldehyde dehydrogenase ( ChBADH ), and betaine homocysteine methyltransferase ( ChBHMT ) using gene fragment resequencing and FLDAS-PCR. Through association analysis of a population of C. hongkongensis in the Maowei Sea, Guangxi, nine SNPs were found to be associated with taurine content, and one SNP was associated with betaine content. Haploid and linkage disequilibrium analyses showed that SNPs in ChCDO formed one linkage group with three haplotypes: ACACA, GTACA and GTTTG. The average taurine content of the corresponding individuals was 873.88, 838.99, and 930.72 μg/g, respectively, indicating the GTTTG haplotype has a significant advantage in terms of taurine content. Conclusions SNPs associated with taurine and betaine contents in C. hongkongensis were identified for the first time. We found that the GTTTG haplotype in the ChCDO coding region has a significant advantage in taurine content. These loci and haplotypes can serve as potential molecular markers for the molecular breeding of C. hongkongensis .

Aquaculture offers a promising source of economic and healthy protein for human consumption, which can improve wellbeing. Viral diseases are the most serious type of diseases affecting aquatic animals and a major obstacle to the development of the aquaculture industry. In the background of antibiotic-free farming, the development and application of antibiotic alternatives has become one of the most important issues in aquaculture. In recent years, many medicinal plants and their active pharmaceutical ingredients have been found to be effective in the treatment and prevention of viral diseases in aquatic animals. Compared with chemical drugs and antibiotics, medicinal plants have fewer side-effects, produce little drug resistance, and exhibit low toxicity to the water environment. Most medicinal plants can effectively improve the growth performance of aquatic animals; thus, they are becoming increasingly valued and widely used in aquaculture. The present review summarizes the promising antiviral activities of medicinal plants and their active pharmaceutical ingredients against aquatic viruses. Furthermore, it also explains their possible mechanisms of action and possible implications in the prevention or treatment of viral diseases in aquaculture. This article could lay the foundation for the future development of harmless drugs for the prevention and control of viral disease outbreaks in aquaculture.

(1) Background: Singapore grouper iridovirus (SGIV) can cause extensive fish deaths. Therefore, developing treatments to combat virulent SGIV is of great economic importance to address this challenge to the grouper aquaculture industry. Green tea is an important medicinal and edible plant throughout the world. In this study, we evaluated the use of green tea components against SGIV infection. (2) Methods: The safe working concentrations of green tea components were identified by cell viability detection and light microscopy. Additionally, the antiviral activity of each green tea component against SGIV infection was determined with light microscopy, an aptamer (Q5c)-based fluorescent molecular probe, and reverse transcription quantitative PCR. (3) Results: The safe working concentrations of green tea components were green tea aqueous extract (GTAE) ≤ 100 μg/mL, green tea polyphenols (TP) ≤ 10 μg/mL, epigallocatechin-3-gallate (EGCG) ≤ 12 μg/mL, (-)-epigallocatechin (EGC) ≤ 10 μg/mL, (-)-epicatechin gallate (EGC) ≤ 5 μg/mL, and (-)-epicatechin (EC) ≤ 50 μg/mL. The relative antiviral activities of the green tea components determined in terms of MCP gene expression were TP > EGCG > GTAE > ECG > EGC > EC, with inhibition rates of 99.34%, 98.31%, 98.23%, 88.62%, 73.80%, and 44.31%, respectively. The antiviral effect of aptamer-Q5c was consistent with the results of qPCR. Also, TP had an excellent antiviral effect in vitro, wherein the mortality of fish in only the SGIV-injection group and TP + SGIV-injection group were 100% and 11.67%, respectively. (4) Conclusions: In conclusion, our results suggest that green tea components have effective antiviral properties against SGIV and may be candidate agents for the effective treatment and control of SGIV infections in grouper aquaculture.

The bactericidal permeability-increasing protein (BPI) and lipopolysaccharide binding protein (LBP) are fundamental to innate immunity. However, their functional diversity and evolutionary conservation in ecologically crucial invertebrates, such as oysters, remain largely understudied. In this study, we identify and characterize a novel homolog of BPI/LBP, designated as ChBPI/LBP in the Hong Kong oyster (Crassostrea hongkongensis). Through structural and phylogenetic analysis, we identify ChBPI/LBP as a distinct member of the BPI protein family, with a high isoelectric point (pI of 9.26), indicating potent cationic BPI-like bactericidal function. We found that ChBPI/LBP is constitutively highly expressed at mucosal sites such as the gills and is rapidly upregulated in hemocytes following a challenge with Aeromonas hydrophila. Recombinant ChBPI/LBP demonstrated potent and specific bactericidal activity against Gram-negative pathogens. These findings suggest that ChBPI/LBP is an important antimicrobial peptide (AMP) effector in the oyster’s immune response. This work provides novel perspectives on the evolutionary mechanisms of innate immunity in bivalves and may have implications for disease management in aquaculture.

Heavy metal accumulation in freshwater ecosystem has become one of the major aquatic environmental concerns for freshwater flora and fauna due to their higher stability and bioaccumulation as well as bio-magnification properties. Furthermore, passing through the food web, these heavy metals affect human populations ultimately. This study assessed the heavy metal accumulation in Cirrhinus mrigala in spring, autumn, and winter at different locations (I, II, and III) of Panjnad headwork. Furthermore, the human health risk assessment for the consumption of C. mrigala from the sampling locations was also carried out. Fish were collected from upper (I), middle (II), and lower (III) stream of Panjnad on a monthly basis. The current study evaluated the accumulation of Aluminum (Al), Arsenic (As), Barium (Ba), and Lead (Pb) in various fish organs (liver, kidney, gills, fins, skin, muscles and bones) and assessed their potential hazard to human health through health risk assessment indicators. The results demonstrated a significant difference (p < 0.05) in heavy metal accumulation in different fish organs, seasons, and locations. The accumulation of Al, As, Ba, and Pb were considerably higher in liver and kidney as compared to the other body organs and followed a trend of liver > kidney > gills > fins > skin > bones > muscle and the overall mean concentrations of metals in different body tissues of C. mrigala were in the order of Al > As > Ba > Pb. The results also concluded that C. mrigala caught from the Panjnad headwork is not safe for human consumption due to higher values of TTHQIng (3.76), THQIng for Ba (3.27) and CRIng for As (6.4742).

ABSTRACT Noble scallop (Chlamys nobilis) is an economically important cultured marine bivalve shellfish common in southern China. Investigation on the molecular regulatory mechanisms of gonadal maturation in scallop is critical in the aquacultural industry. Here, gonads in maturing stage were obtained from noble scallops and sequenced using an Illumina high-throughput sequencer, producing 6.68 and 6.70 Gb of data for the ovary and testis, respectively. Reproduction-related genes, including vasa, nanos, and vitellogenin, and sex-determining genes, such as FoxL2, Dmrt, and sox9, were detected. Transcriptome comparison revealed 2,842 differentially expressed genes (DEGs), of which 591 exhibited biased expression in the ovary and 2,251 exhibited biased expression in the testis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of the DEGs were conducted. Results showed that GO terms and KEGG pathways related to protein glycosylation, fatty acid biosynthetic processes, hydrolase activity, and AMPK were enriched in the ovary, whereas those related to male organ formation and spermiogenesis were enriched in the testis. The glycosphingolipid biosynthesis pathway was identified for the first time in a mollusc testis.The present study provides the first transcriptomic analysis of C. nobilis, which will help clarify the molecular mechanisms of gonadal maturation.

Glycogen, a critical nutrient in Crassostrea hongkongensis , exhibits essential biological properties, with its quantitative levels serving as a pivotal parameter for phenotypic selection and genetic improvement of superior oyster strains. To investigate the characteristics of glycogen content and identify single nucleotide polymorphisms (SNPs) associated with this trait in C. hongkongensis , we cloned the full-length cDNA of key genes involved in glycogen metabolism, determined glycogen content and gene expression in different tissues and months of the oyster specimen collection, and developed SNPs in the gene coding region. The results demonstrated that glycogen synthase ( ChGS ) and glycogen phosphorylase ( ChGP ) are key genes regulating glycogen metabolism in C. hongkongensis . Both genes were ubiquitously expressed across all six analyzed tissues: gills, adductor muscle, mantle, labial palps, gonads, and digestive gland. Notably, mRNA expression levels of ChGS and ChGP in gonad and visceral tissues exhibited seasonal fluctuations, which showed significant correlation with glycogen content dynamics. Fifteen SNP markers were identified within the coding regions of ChGS and ChGP using fragment-length discrepant allele-specific polymerase chain reaction. The success rate of SNP identification was 37.5% (15/40). Using association analysis, one SNP located in the coding region of ChGS was found to be associated with glycogen content. These results provide potential molecular markers that can be used for the selection and breeding of glycogen traits in C. hongkongensis , and demonstrate the potential influence of ChGS and ChGP on glycogen content.

Cetacean-watching tourism has become an economically important recreation industry, but can compromise cetacean viability and hence tourism sustainability. While current management tactics pay much attention on industrialized cetacean-watching tourisms, impacts of tours operated by motorized boats in inshore waters are seldom discussed. This study investigated the spatial and temporal activities of dolphin-watching tours in Sanniang Bay, China, where tours specifically focus on Indo-Pacific humpback dolphins (Sousa chinensis). The primary boat-dolphin interaction directly overlaps with a core habitat of humpback dolphins. Average tour duration was shorter than 40 min and approximately one third of time was spent on following dolphins. Monthly tour activities were extremely high in February, early May, August, and October that corresponded to Chinese national festivals. An eastward shift of primary interaction site during high-tour-activity months implies a long-term tour impacts on habitat use of humpback dolphins in northern Beibu Gulf. We urge a collaboration and coordination between boat captains, tour managers, maritime administrative, academic teams, and NGOs to systematically collect tour statistics in Sanniang Bay, including daily tour and visitor numbers, encounter duration and locations, and unsustainable maritime activities. As eco-tourisms targeting humpback dolphins and other coastal cetaceans adopting small motorized boats are rapidly growing in southeastern Asia, management guidelines involving codes of conduct, allowable daily trips, and sustainable tourism tactics are urgently needed before the tourism becomes industrialized and economically oriented. Variables and statistics presented in this study can provide a baseline proxy to help design management guidelines to minimize unsustainable impacts on the target animals.

Bone morphogenetic proteins (BMPs) are multifunctional secreted cytokines that play important roles in bone formation. In the present study, a homologous BMP3 gene was identified from Pinctada fucata (PfBMP3). PfBMP3 was 2710 bp length, contained 1470 bp of ORFs. PfBMP3 gene was expressed at all stages tested, with the highest expression during the trochophore and metamorphosis stages. PfBMP3 gene was expressed in all tissues tested, with high levels detected in the gill and mantle. In situ hybridization of the mantle revealed that PfBMP3 was highly expressed in the inner epidermis of the inner fold, the outer epidermis of the middle fold, and outer epidermis of the mantle. In the shell notching experiments, the expression of PfBMP3 was up-regulated after treatment. These results indicated that PfBMP3 might play a role in P. fucata shell formation. The expression level of PfBMP3 in a low calcium aquacultural environment was higher than that in a high calcium aquacultural environment, suggesting that PfBMP3 might participate in calcium ion metabolism regulation. RNA interference (RNAi) showed that the expression level of the calmodulin gene PfCaM was down-regulated after RNAi, implying that the involvement of PfBMP3 in calcium ion metabolism might be through action with PfCaM.

The chloride channel 7 gene ( CLC7 ) of the Hong Kong oyster Crassostrea hongkongensis was cloned and named ChCLC7 . The cDNA was 2 572 bp in length, with a 5′ non-coding region containing 25 bp, a 3′ non-coding region containing 327 bp, and an open reading frame of 2 298 bp. ChCLC7 has 96.8% and 92.1% homology with CLC7 of Crassostrea gigas and Crassostrea virginica , respectively, and it was clustered with CLC7 of C. gigas and C. virginica . QRT-PCR showed that ChCLC7 was expressed in all eight tissues, with the highest in adductor muscle and second in gill. The ChCLC7 expression pattern in gill was altered significantly under high salinity stress with an overall upward and then downward trend. After RNA interference, the expression of ChCLC7 and survival rate of oyster under high salinity stress was reduced significantly, and so did the concentration of hemolymph chloride ion in 48–96 h after RNA interference. We believed that ChCLC7 could play an important role in osmoregulation of C. hongkongensis by regulating Cl − transport. This study provided data for the analysis of molecular mechanism against oyster salinity stress.