Crab Scylla Paramamosain Research Articles

The Health Risk for Consumers Under Heavy Metal Contamination Scenarios in Future: Reduce Bioaccumulation of Cd Pollutants in Estuary Mud Crab (Scylla Paramamosain) Through the Antagonism of Organic or Inorganic Se

The Health Risk for Consumers Under Heavy Metal Contamination Scenarios in Future: Reduce Bioaccumulation of Cd Pollutants in Estuary Mud Crab (Scylla Paramamosain) Through the Antagonism of Organic or Inorganic Se

Effects of lactic acid bacteria activation methods on mud crab ( Scylla paramamosain ) hatching rate and the microbiota in larval culture

Effects of lactic acid bacteria activation methods on mud crab ( <i>Scylla paramamosain</i> ) hatching rate and the microbiota in larval culture

MiR-9875 functions in antiviral immunity by targeting PDCD6 in mud crab (Scylla paramamosain)

ABSTRACT Programmed cell death 6 (PDCD6) is a well-known apoptosis regulator that is involved in the immunity of mammals. However, the effects of miRNA-mediated regulation of PDCD6 expression on apoptosis and virus infection in organisms, especially in marine invertebrates, have not been extensively explored. In this study, PDCD6 of mud crab (Scylla paramamosain) (Sp-PDCD6) was characterized. The results showed that Sp-PDCD6 contains five EF-hands domains and could suppress virus infection via apoptosis promotion. It also presented that Sp-PDCD6 was directly targeted by miR-9875 in vitro and in vivo, miR-9875 served as a positive regulator during the virus invasion. The findings indicated that the miR-9875-PDCD6 pathway possessed fundamental effects on the immune response to virus infection in mud crab. Therefore, our research provided a novel insight into the roles of both miR-9875 and PDCD6 in the regulation of apoptosis and virus defense in mud crab.

High-throughput sequencing reveals the core gut microbiota of the mud crab (Scylla paramamosain) in different coastal regions of southern China

BackgroundScylla paramamosain is a commercially important mud crab. The microbiota is a community that inhabits the crab intestine, and is important for physiological functional and host health.ResultsProteobacteria, Firmicutes, Bacteroidetes, Tenericutes, Spirochaetae and Fusobacteria were the dominant phyla of the 36 representative phyla. Eleven genera of the 820 representative genera were considered as core gut microbiota and were distributed in the five dominant phyla. The core genus of the Proteobacteria included Arcobacter, Photobacterium, Vibrio, Shewanella and Desulfovibrio. The other four phyla contained one or two genera. Male and female crab samples had two different core genera, (male samples: Psychrilyobacter & Lactococcus; female samples: Clostridium_sensu_stricto_11 and Candidatus_Bacilloplasma).ConclusionsThis is the first time core intestinal microbiota have been identified in crab from nine coastal regions of southern China. This study provides sequencing data related to the gut microbiota of S. paramamosain, and may contribute to probiotic development for S. paramamosain aquaculture industries.

Impact of different rearing systems on survival, growth and quality of mud crab (Scylla paramamosain) megalopae reared from early zoeae

This study aimed to compare the effects of four different rearing systems—namely clear water, green water, recirculating water and biofloc water systems—on survival, growth and quality of mud crab (Scylla paramamosain) megalopae reared from early zoeae. Twelve 60-L plastic buckets filled with 50 L of disinfected seawater were stocked with 20 larvae of zoea 1 (Z1) L−1. The larvae were fed both probiotic-enriched L-strain rotifers (Brachionus plicatilis) and probiotic-enriched Artemia (Artemia franciscana) in all systems. After 20 days of culture, the green water system resulted in the highest survival to megalopae than all the other systems. The survival of megalopae reared under the biofloc water system was similar to that of the clear water system, but both systems exhibited higher survival than the recirculating water system. However, larval growth performance was not affected by the various rearing systems. The quality of megalopae produced under these systems was determined by ammonia and simulated transport stress tests. The ammonia stress test did not show a significant difference in the quality of megalopae, but the simulated transport stress test demonstrated a significant effect of rearing system on the quality of mud crab megalopae. The resistance to the air exposure until the end of the 48 h of transport was observed in the green water system. Overall, the results of the present study revealed that the green water system is the most suitable for rearing Scylla paramamosain larvae from Z1 to megalopa stage.

The food composition in the Scylla paramamosain's stomach growing in the mangrove forest and industrial farming at Can Gio district, Ho Chi Minh City

Mud crab (Scylla paramamosain) farming is widely developed in Can Gio, however the economic value is not so high because buyers always prefer the crabs which are caught in the mangrove. The hypothesis is that whether there are differences in the food composition between two crab types (farming and mangrove) or not. So, the research was conducted at Can Gio mangrove forest to analyze the stomach content of S. paramamosain. The results were the food ingredients in S. paramamosain in Can Gio including snail shells, crab shells, animal materials, leaves, sand and unidentified materials. The snail shells, animal materials and leaves were dominant food on mangrove Scylla crab’s stomach. Meanwhile, the crab shells, animal materials and sand were main foods in the farming Scylla crab’s stomach. Leaves was the new food composition recorded in S. paramamosain stomach compared to previous studies. The result initially showed that the food composition affected the quality of Scylla paramamosain growing in Can Gio mangrove forest.

Coupled changes of bacterial community and function in the gut of mud crab (Scylla Paramamosain) in response to Baimang disease

Increasing evidence has revealed a close association between intestinal bacterial community and hosts health. However, it is unclear whether and what extend Baimang disease alters the intestinal microbiota in mud crab (Scylla paramamosain). Here, we conducted intestinal contents Illumina sequencing of healthy and Baimang diseased mud crab (S. paramamosain) to understand bacterial community variations among health status. In addition, bacterial functional predication was used to investigate whether and how the bacteria variations further change their functions? The phyla of Proteobacteria, Fusobacteria, Cyanobacteria, Tenericutes, Firmicutes, Bacteroidetes, and Spirochaetae constituted over 96.44% of the total intestinal bacteria, with being the dominant taxa. The 7 most significantly different orders, including the increased four orders of Clostridiales, Entomoplasmatales, Bacteroidales, and Mycoplasmatales and the decreased three orders of Vibrionales, Campylobacterales, and Fusobacteriales, accounted for 61.14% dissimilarity, probably being the indicator taxa of Baimang disease. Accordingly, 12 Kyoto Encyclopedia of Genes and Genomes orthologies in level 3 shifted significantly at the diseased crabs. Especially, bacterial secretion system, secretion system, lipopolysaccharide biosynthesis proteins and Vibrio cholerae pathogenic cycle, being related to bacterial virulence, were reduced. In addition, the reduced butanoate metabolism, and induced methane metabolism and one carbon pool by folate were important metabolic processes of probiotic, such as Bacteroides spp. and Clostridium spp., with playing critical roles in host health. This study suggests that Baimang disease coupled altered the intestinal bacterial communities and functions, providing timely information for further analysis the influencing mechanism of Baimang disease in mud crab (S. paramamosain).

Feeding in the megalopae of the mud crab (Scylla paramamosain): mechanisms, plasticity, role of chelipeds and effect of prey density

We used microscopic video records to analyse the behaviour of mud crab megalopae (Scylla paramamosain) fed on rotifers (Brachiomus spp.), Artemia sp. or copepods (Schmackeria dubin). The megalopae were able to capture prey whose sizes ranged from no larger than Artemia nauplii to no smaller than adult Artemia. The megalopae employed three feeding modes: (1) Ambush-Prey mode, (2) Swim-Suspension-Feed mode and (3) Sit-Sweep mode. These involved raptorial feeding, suspension feeding and an in-between raptorial-suspension feeding mode, depending on the size of the prey and their density in the surrounding water. The chelipeds played an important role in feeding. Megalopae used the chelipeds to grip or sweep prey items and their movement generated eddies that can increase feeding efficiency. To verify the contribution of the chelipeds to feeding efficiency, we observed and compared the animals under three cheliped treatment regimes: (1) Autotomized – chelipeds removed by induced autotomy; (2) Glued – chelipeds glued at the dactylus-propodus joint to eliminate their ability to grip; and (3) Control – normal chelipeds. The feeding rates of the autotomized and glued treatments were lower than those of the controls, demonstrating that the chelipeds assist in feeding but that the megalopae can still feed without them. The density of prey also affected feeding efficiency. Feeding rate and prey density were positively correlated. When prey density was high, megalopae were able to feed in excess of their nutritional requirements. The study shows that mud crab megalopae respond flexibly to variations in feeding conditions, such as damaged chelipeds, as well as prey size and density. We postulate that this plasticity evolved in response to the dilute and patchy prey conditions of the estuarine environment. All the analysed behaviours are illustrated with video sequences.

Isolation, gene cloning and expression profile of a pathogen recognition protein: A serine proteinase homolog ( Sp-SPH) involved in the antibacterial response in the crab Scylla paramamosain

To identify the frontline defense molecules against microbial infection in the crab Scylla paramamosain, a live crab pathogenic microbe, Vibrio parahaemolyticus, was recruited as an affinity matrix to isolate innate immune factors from crab hemocytes lysate. Interestingly, a serine proteinase homolog ( Sp-SPH) was obtained together with an antimicrobial peptide-antilipopolysaccharide factor ( Sp-ALF). We then determined the full-length cDNA sequence of Sp-SPH, which contained 1298 bp with an open reading frame of 1107 bp encoding 369 amino acid residues. Multiple alignment analysis showed that the deduced amino acid sequences of Sp-SPH shared overall identity (83.8%) with those of SPH-containing proteins from other crab species. Tissue distribution analysis indicated that the Sp-SPH transcripts were present in various tissues including eye stalk, subcuticular epidermis, gill, hemocyte, stomach, thorax ganglion, brain and muscle of S. paramamosain. The Sp-SPH was highly expressed in selected different development stages including embryo (I, II, III and V), zoea (I), megalopa, and juvenile. Importantly, the prophenoloxidase was also present in the embryos, zoea, juvenile and adult crabs, but relatively lower in megalopa compared to those of other stages. Furthermore, the Sp-SPH mRNA expression showed a statistically significant increase ( P < 0.05) in both hemocyte and subcuticular epidermis at 24 h, and in gill at 96 h after challenge of V. parahaemolyticus determined by quantitative real-time PCR. Taken together, the live-bacterial-binding activity and the acute-phase response against bacterial infection of Sp-SPH suggested that it might function as an innate immune recognition molecule and play a key role in host defense against microbe invasion in the crab S. paramamosain.

Identification of genes differentially expressed in hemocytes of Scylla paramamosain in response to lipopolysaccharide

Although the crab Scylla paramamosain has been cultured in China for a long time, little knowledge is available on how crabs respond to infection by bacteria. A forward suppression subtractive hybridization (SSH) cDNA library was constructed from their hemocytes and the up-regulated genes were identified in order to isolate differentially expressed genes in S. paramamosain in response to bacterial lipopolysaccharide (LPS). A total of 721 clones on the middle scale in the SSH library were sequenced. Among these genes, 271 potentially functional genes were recognized based on the BLAST searches in NCBI and were categorized into seven groups in association with different biological processes using AmiGO against the Gene Ontology database. Of the 271 genes, 269 translatable DNA sequences were predicted to be proteins, and the putative amino acid sequences were searched for conserved domains and proteins using the CD-Search service and BLASTp. Among 271 genes, 179 (66.1%) were annotated to be involved in different biological processes, while 92 genes (33.9%) were classified as an unknown-function gene group. It was noted that only 18 of the 271 genes (6.6%) had previously been reported in other crustaceans and most of the screened genes showed less similarity to known sequences based on BLASTn results, suggesting that 253 genes were found for the first time in S. paramamosain. Furthermore, two up-regulated genes screened from the SSH library were selected for full-length cDNA sequence cloning and in vivo expression study, including Sp-superoxide dismutase ( Sp-Cu-ZnSOD) gene and Sp-serpin gene. The differential expression pattern of the two genes during the time course of LPS challenge was analyzed using real-time PCR. We found that both genes were significantly expressed in LPS-challenged crabs in comparison with control. Taken together, the study primarily provides the data of the up-regulated genes associated with different biological processes in S. paramamosain in response to LPS, by which the interesting genes or proteins potentially involved in the innate immune defense of S. paramamosain will be investigated in future.

Potential of Stock Enhancement for Decapod Crustaceans

To evaluate the potential of stock enhancement for decapod crustaceans, we analyzed stock enhancement programs for 4 species: the penaeid prawns (Penaeus japonicus) in Japan and (Penaeus chinensis) China, the European lobster (Homarus gammarus) in Norway, and the mud crab (Scylla paramamosain) in Japan, for which stocking effectiveness has been intensively examined. For each species, we summarized the life cycle, fishery, and stocking programs and then comparatively analyzed the recapture rates, the yield from the released individuals (YPR), and the economic efficiency. Scylla paramamosain had some advantages in stock enhancement, including restricted living areas such as bays and estuaries, a large body size, and high values of the ratio of price per landed individual to the cost per released juvenile. These characteristics promised higher values of YPR and economic efficiency, even at lower recapture rates. Therefore, hatchery releases affect areas with small stocks of S. paramamosain. This scenario might also be inferred for H. gammarus, which had the highest YPR and does not generally migrate from the release site, although the economic efficiency was low due to the high cost of juvenile production. On the other hand, fishery productions of the penaeid prawns, which had a lower YPR, could not be augmented without a huge number of released juveniles and the maintenance of nursery habitats. The restocking is a more cost-effective measure for sustainable fishery production than only a sea ranching (put and take) operation. Therefore, hatchery releases for decapod crustaceans should be applied to rebuild wild stocks (restocking) with appropriate fishing regulations and habitat restoration. In the future, selection of target species for stock enhancement programs should take into account the necessity for restocking and their life history characteristics.

Diversity of bacteria isolated from crustacea larvae and their rearing water

The bacteria in the genus Vibrio are heterothrophic, which exist in the larval rearing water of Crustacea and often show diverse pathogenicities to marine animals. In order to assess the bacterial diversity associated with Crustacean seed production, 32 strains were isolated from black tiger shrimp (Penaeus monodon) and mangrove crab (Scylla paramamosain) larvae and their rearing-water and characterized using biochemical and molecular approaches. Two or more genotypically different species were identified. The vibriosis of black tiger shrimp was causes by V. harveyi, V. alginolyticus and Vibrio spp. predominantly, while that of crab by V. harveyi and V. alginolyticus only.