Previous studies have shown that Vibrio splendidus infection causes mitochondrial damage in Apostichopus japonicus coelomocytes,leading to the production of excessive reactive oxygen species(ROS)and irreversible apopt...Previous studies have shown that Vibrio splendidus infection causes mitochondrial damage in Apostichopus japonicus coelomocytes,leading to the production of excessive reactive oxygen species(ROS)and irreversible apoptotic cell death.Emerging evidence suggests that mitochondrial autophagy(mitophagy)is the most effective method for eliminating damaged mitochondria and ROS,with choline dehydrogenase(CHDH)identified as a novel mitophagy receptor that can recognize non-ubiquitin damage signals and microtubule-associated protein 1 light chain 3(LC3)in vertebrates.However,the functional role of CHDH in invertebrates is largely unknown.In this study,we observed a significant increase in the mRNA and protein expression levels of A.japonicus CHDH(AjCHDH)in response to V.splendidus infection and lipopolysaccharide(LPS)challenge,consistent with changes in mitophagy under the same conditions.Notably,AjCHDH was localized to the mitochondria rather than the cytosol following V.splendidus infection.Moreover,AjCHDH knockdown using si RNA transfection significantly reduced mitophagy levels,as observed through transmission electron microscopy and confocal microscopy.Further investigation into the molecular mechanisms underlying CHDH-regulated mitophagy showed that AjCHDH lacked an LC3-interacting region(LIR)for direct binding to LC3 but possessed a FB1 structural domain that binds to SQSTM1.The interaction between AjCHDH and SQSTM1 was further confirmed by immunoprecipitation analysis.Furthermore,laser confocal microscopy indicated that SQSTM1 and LC3 were recruited by AjCHDH in coelomocytes and HEK293T cells.In contrast,AjCHDH interference hindered SQSTM1 and LC3 recruitment to the mitochondria,a critical step in damaged mitochondrial degradation.Thus,AjCHDH interference led to a significant increase in both mitochondrial and intracellular ROS,followed by increased apoptosis and decreased coelomocyte survival.Collectively,these findings indicate that AjCHDH-mediated mitophagy plays a crucial role in coelomocyte survival in A.japonicus following V.splendidus infection.展开更多
The sea cucumber Apostichopus japonicus plays important roles in marine benthic ecosystem as environmental cleaners,and it is the important aquaculture species in China.High water temperature poses critical threat for...The sea cucumber Apostichopus japonicus plays important roles in marine benthic ecosystem as environmental cleaners,and it is the important aquaculture species in China.High water temperature poses critical threat for the survival of A.japonicus,which has resulted in extensive death in summer.To explore the genes expression profiles under different levels of heat stress,the high-throughput RNA-seq was applied in this study.Our results revealed a total of 1371,1225 and 1408 differentially expressed genes(DEGs)in 26℃for 6 h,26℃for 48 h and 30℃for 6 h respectively in comparison with Control group.The pathway analysis suggested“Protein processing in endoplasmic reticulum(ER)”was significantly enriched in all these heat stress(HS)treatment groups.The expression results of key DEGs in this pathway(Hsp70,Derlin,NEF,PDI,GPR94 and ERP57)by qRT-PCR was in accordance with the RNA-seq data.The subcluster analysis of DEGs revealed that a variety of heat shock proteins(HSPs)and calcium ion binding proteins had an obvious up-regulated expression in 26℃for 6 h,comparatively low expression in 26℃for 48 h,and the highest expression in 30℃for 6 h.The other DEGs subcluster,consisting of critical components of extracellular matrix(ECM)and a subset of peptidases and proteases,showed significantly rising tendency in 30℃for 6 h.Additionally,the expression of matrix metalloproteases(MMP1,MMP16 and MMP19)was prominently affected by HS,and peaked in 30℃for 6 h.This study provides a series of candidate genes for further study about heat shock response in A.japonicus,especially genes associated with protein processing in ER and regulation of ECM,which also offers new insights into cellular homeostasis under stressful conditions in marine invertebrates.展开更多
Sea cucumber(Apostichopus japonicus)is an excellent model for investigating effects of bottom-dwellers on carbon mig-ration and transformation.However,the molecular mechanism of respiratory metabolism process variatio...Sea cucumber(Apostichopus japonicus)is an excellent model for investigating effects of bottom-dwellers on carbon mig-ration and transformation.However,the molecular mechanism of respiratory metabolism process variation caused by feeding rations is poorly understood.In this study,treatment groups set as 1%(about 0.63g),3%,and 7%of total body weight(named F1,F3 and F7 groups respectively).The potential molecular mechanisms behind the functions of respiratory tree and body wall were investigated by RNA-Seq.A total of 52411 expressed genes were identified from 89342 expressed transcripts.The results showed 759,254 and 334 genes were up-regulated,and 334,445 and 992 genes were down-regulated in respiratory tree of F1 vs.F3,F1 vs.F7 and F3 vs.F7,respectively.Meanwhile,2070,1601 and 896 genes were up-regulated,and 1303,1337 and 1144 genes were down-regulated in body wall between F1 vs.F3,F1 vs.F7 and F3 vs.F7,respectively.Differentially expressed genes were enriched in salivary secretion and ECM-receptor interaction pathways in respiratory tree,and in various types of N-glycan biosynthesis,ribosome and sphingolipid metabolism pathways in body wall.These results suggested respiratory tree and body wall were involved in activation of respiratory metabolisms in response to different feeding rations.Our research provided valuable knowledge for physiological differences in res-piratory metabolism.展开更多
Aestivation is a common strategy of sea cucumbers(Apostichopus japonicus)in response to high-temperature conditions.Previous studies have individually investigated the immune and physiological alterations at the aesti...Aestivation is a common strategy of sea cucumbers(Apostichopus japonicus)in response to high-temperature conditions.Previous studies have individually investigated the immune and physiological alterations at the aestivation stage.However,these studies have not evaluated the relationship between immunity and physiology.In this study,we explored the transcriptome and metabolome of A.japonicus during the aestivation stage to study the relationship.The transcriptome analysis of dormant(aestivation)and revived A.japonicus generated 2368 differentially expressed genes,including 927 downregulated genes and 1441 upregulated genes.Based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses,the downregulated genes in the dormant group were found to be involved in DNA replication,RNA metabolic process,and protein metabolism,which results in the inhibition of motility,skeletal development,neural activity,cell proliferation,and development of A.japonicus.In contrast,the upregulated genes were found to be associated with fatty acid metabolism,carbohydrate hydrolysis,and phagocytosis.In the metabolome analysis,the downregulated metabolites were found to be associated with fatty acid metabolism,starch and sucrose metabolism,and TCA cycle.This indicates that dormant sea cucumbers consume reserved carbohydrates and fatty acids to maintain low levels of energy supply.The protein-protein interaction network analysis further revealed that carbohydrate hydrolysis promoted phagocytosis activity in the dormant group.This study provides new insights into potential molecular mechanisms of sea cucumber survival in high-temperature conditions,which is critical in aquaculture of sea cucumbers.展开更多
The construction of enrichment library proves to be one of the efficient approaches for isolating microsatellites in this study. The genomic DNA of sea cucumber was digested with HaeIII and size-selected DNA fragments...The construction of enrichment library proves to be one of the efficient approaches for isolating microsatellites in this study. The genomic DNA of sea cucumber was digested with HaeIII and size-selected DNA fragments (250-700 bp) were ligated to an adaptor. Microsatellite-containing sequences were captured by using a combination of GA and CA probes, which were attached to a nylon membrane. The microsatellite enrichment library constructed in this study consisted of approximately 700 clones. Two hun-dred and thirty-two clones reacted positively after the library screening procedure. Of the 50 clones sequenced, all contained at least one microsatellite and one duplicate clone was found. Approximately 86% of the sequenced fragments permitted to design primers for sequence tagged microsatellite site (STMS).展开更多
Organisms produce high levels of reactive oxygen species(ROS)to kill pathogens or act as signaling molecules to induce immune responses;however,excessive ROS can result in cell death.To maintain ROS balance and cell s...Organisms produce high levels of reactive oxygen species(ROS)to kill pathogens or act as signaling molecules to induce immune responses;however,excessive ROS can result in cell death.To maintain ROS balance and cell survival,mitophagy selectively eliminates damaged mitochondria via mitophagy receptors in vertebrates.In marine invertebrates,however,mitophagy and its functions remain largely unknown.In the current study,Vibrio splendidus infection damaged mitochondrial morphology in coelomocytes and reduced mitochondrial membrane potential(ΔΨm)and mitophagosome formation.The colocalization of mitochondria and lysosomes further confirmed that lipopolysaccharide(LPS)treatment increased mitophagy flux.To explore the regulatory mechanism of mitophagy,we cloned Bcl2/adenovirus E1 B 19 kDa protein-interacting protein 3(BNIP3),a common mitophagy receptor,from sea cucumber Apostichopus japonicus(Aj BNIP3)and confirmed that Aj BNIP3 was significantly induced and accumulated in mitochondria after V.splendidus infection and LPS exposure.At the mitochondrial membrane,Aj BNIP3 interacts with microtubule-associated protein 1 light chain 3(LC3)on phagophore membranes to mediate mitophagy.After Aj BNIP3 interference,mitophagy flux decreased significantly.Furthermore,Aj BNIP3-mediated mitophagy was activated by ROS following the addition of exogenous hydrogen peroxide(H2 O2),ROS scavengers,and ROS inhibitors.Finally,inhibition of BNIP3-mediated mitophagy by Aj BNIP3 small interfering RNA(si RNA)or high concentrations of lactate increased apoptosis and decreased coelomocyte survival.These findings highlight the essential role of Aj BNIP3 in damaged mitochondrial degradation during mitophagy.This mitophagy activity is required for coelomocyte survival in A.japonicus against V.splendidus infection.展开更多
Skin ulceration syndrome(SUS)is the main diseases aff ected the development of sea cucumber(Apostichopus japonicus)culture industries.To better observe the changes in the sea cucumber A.japonicus with SUS and understa...Skin ulceration syndrome(SUS)is the main diseases aff ected the development of sea cucumber(Apostichopus japonicus)culture industries.To better observe the changes in the sea cucumber A.japonicus with SUS and understand the pathogenesis of the disease,activities of superoxide dismutase(SOD),catalase(CAT),and level of malondialdehyde(MDA)in coelomic fluid were detected using the Assay Kit and metabolites in the body wall were assessed using ultra-performance liquid chromatography and quadrupole-time of flight mass spectrometry.The results indicated that level of MDA was increased during SUS compared with healthy individuals(P<0.01),but activities of SOD and CAT were reduced(P<0.05).In metabolomics analysis,metabolites,such as adenosine,choline,betaine aldehyde,palmitic acid,and taurine,were found to be upregulated and 2-oxoadipic acid,anthranilic acid(vitamin L1),thioetheramide-PC,cholesterol-3-sulfate,and pentadecanoic acid were downregulated(VIP>1 and P<0.1).Pathway enrichment analysis indicated most enrichment of KEGG pathways were mainly related to energy metabolism,immunity,and osmoregulation such as ABC transporters,glycine,serine and threonine metabolism,tryptophan metabolism and neuroactive ligand-receptor interaction.Our study reflected the difference in enzyme activity and metabolites between A.japonicus with SUS and those without,which will provide reference data for investigating SUS.展开更多
Monoculture of sea cucumber(pond S) and polyculture of shrimp with sea cucumber(pond SS) were established to evaluate the effect of shrimp on the environmental conditions of sea cucumber farming pond. Contributions of...Monoculture of sea cucumber(pond S) and polyculture of shrimp with sea cucumber(pond SS) were established to evaluate the effect of shrimp on the environmental conditions of sea cucumber farming pond. Contributions of sediment organic matter(SOM2) resuspended from benthic sediment and the suspended particulate organic matter(SPOM) deposited from the water column to the precipitated organic matter(SOM1) collected with sediment traps were estimated with carbon stable isotope analysis. The results showed that the levels of SPOM and SOM2 in pond SS significantly decreased in comparison with those in pond S at the end of experiment(P < 0.05), indicating that co-culturing shrimp in sea cucumber farming pond could purify the farming water. Carbon stable isotope analysis showed that the proportion of SOM2 in SOM1 in pond SS(84.97% ± 0.38%) was significantly lower than that in pond S(95.20% ± 0.30%)(P < 0.05), suggesting that the resuspension of organic matter from benthic sediment into overlying water was reduced in polyculture pond. In contrast, the proportion of SPOM in SOM1 in pond SS(15.03% ± 0.38%) was significantly higher than that in pond S(4.80% ± 0.30%)(P < 0.05), indicating that the sedimentation of SPOM from water column was enhanced in pond SS owing to the biodeposition effect of shrimp.展开更多
Apostichopus japonicus is an important invertebrate that is widely used as a tonic food in Asian countries.The purpose of this study is to purify and identify a class of compound,the saponins,from the body wall of A.j...Apostichopus japonicus is an important invertebrate that is widely used as a tonic food in Asian countries.The purpose of this study is to purify and identify a class of compound,the saponins,from the body wall of A.japonicus,and to establish a new me-thod to determine the quantity of saponins in the sea cucumber.In this study,the saponins of A.japonicus,cladoloside A(CA),were ob-tained from 80%ethanol extract by column chromatography for the first time and were characterized using the spectral method.The resulting purified saponins were then profiled using ^(1)HNMR,^(13)CNMR,and ESI-MS,which revealed the CA molecular formula of C_(53)H_(82)O_(2) and contained a triterpenoid backbone,a methylglucopyranosyl moiety,a quinovopyranosyl,and two xylopyranosyls.A me-thod for the quantitative determination of CA,comprising microwave-assisted extraction,high-performance liquid chromatography,and diode array detector method,was established.Extraction efficiency was optimized by changing microwave power,extraction sol-vent,volume,time,and temperature.Results showed that under the optimum conditions(extraction time of 10 min,temperature of 45℃,and solvent of 25 mL 70%ethanol under 400 W),the detection limit of CA was 0.0015 mg mL^(−1),and the recoveries of CA from samples at spiking levels of 10,20,and 50μg g^(−1) ranged from 90.1%-104%.The proposed method was successfully applied to ana-lyze the saponins in different tissues of A.japonicus collected in different seasons.The method developed in this study can provide quantitative technical support for the quality control of A.japonicus.展开更多
The present study was conducted to determine the change of digestive physiology in sea cucumber Apostichopus japonicus(Selenka) induced by corn kernels meal and soybean meal in diets. Four experimental diets were test...The present study was conducted to determine the change of digestive physiology in sea cucumber Apostichopus japonicus(Selenka) induced by corn kernels meal and soybean meal in diets. Four experimental diets were tested, in which Sargassum thunbergii was proportionally replaced by the mixture of corn kernels meal and soybean meal. The growth performance, body composition and intestinal digestive enzyme activities in A. japonicus fed these 4 diets were examined. Results showed that the sea cucumber exhibited the maximum growth rate when 20% of S. thunbergii in the diet was replaced by corn kernels meal and soybean meal, while 40% of S. thunbergii in the diet can be replaced by the mixture of corn kernels meal and soybean meal without adversely affecting growth performance of A. japonicus. The activities of intestinal trypsin and amylase in A. japonicus can be significantly altered by corn kernels meal and soybean meal in diets. Trypsin activity in the intestine of A. japonicus significantly increased in the treatment groups compared to the control, suggesting that the supplement of corn kernels meal and soybean meal in the diets might increase the intestinal trypsin activity of A. japonicus. However, amylase activity in the intestine of A. japonicus remarkably decreased with the increasing replacement level of S. thunbergii by the mixture of corn kernels meal and soybean meal, suggesting that supplement of corn kernels meal and soybean meal in the diets might decrease the intestinal amylase activity of A. japonicus.展开更多
F-type lectins(Fucolectins)are carbohydrate-binding proteins and play important roles in innate immune responses against pathogenic microbial invasion.In our previous research,we found that two homologous Fucolectin g...F-type lectins(Fucolectins)are carbohydrate-binding proteins and play important roles in innate immune responses against pathogenic microbial invasion.In our previous research,we found that two homologous Fucolectin genes,AjFTL-1 and AjFTL-2,exhibited different expression profiles after lipopolysaccharides(LPS)challenge in Apostichopus japonicus.However,the transcriptional regulation mechanism of these two genes remains largely unknown.In this study,the 5'flanking regions of Aj FTL-1 and Aj FTL-2 genes were cloned and the promoter activities were studied in epithelioma papulosum cyprinid(EPC)cell system.First,in silico analysis indicated that these two promoters both contain numerous putative transcription factor binding sites including NF-κB,CREB,and CREBP1,and both contain a TATA box.Additionally,luciferase assay and progressive 5'truncation analysis revealed that AjFTL-1 and AjFTL-2 both possess high promoter activities in EPC cells.Moreover,the luciferase activity of AjFTL-1 promoter was significantly regulated by peptidoglycan(PGN)and mannan(MAN),while AjFTL-2 promoter was prominently regulated by LPS and MAN,indicating Aj FTL-1 and Aj FTL-2 genes showed different transcriptional regulation pattern under different immune stimulation.More importantly,analyses of the functional promoter regions revealed the presence of two potential NF-κB binding sites(-769 bp to-761 bp,-185 bp to-172 bp)in Aj FTL-1 and one potential binding site(-530 to-517 bp)in Aj FTL-2.Different truncated reporter vectors and expression vector co-transfection revealed that transcription factor NF-κB/Rel could significantly increase the AjFTL-2 promoter activity,but not AjFTL-1 promoter activity.These findings indicated that in marine invertebrates,different Fucolectin members differ in transcription regulations and expression patterns,and might play different roles in immune defenses during pathogen infection.展开更多
Abstract The unfolded protein response(UPR)is an important protective and compensatory strategy used during endoplasmic reticulum stress caused by factors including glucose starvation,low pH,or heat shock.However,ther...Abstract The unfolded protein response(UPR)is an important protective and compensatory strategy used during endoplasmic reticulum stress caused by factors including glucose starvation,low pH,or heat shock.However,there is very little information on the possible role(s)of the UPR under adverse conditions experienced by marine invertebrates.We observed that rough endoplasmic reticulum(ER)was dramatically expanded and numerous autophagosomes were accumulated in the intestinal cells of sea cucumbers,Apostichopus japonicus,under heat stress(4 h at 25°C compared with 15°C controls).Moreover,heat stress led to sharp increases in the relative transcript and protein expression levels of two primary ER chaperones:the endoplasmic reticulum resident protein 29-like(ERP29)and protein disulfi de-isomerase A6-like(PDIA6).These results suggest a potential adaptive mechanism to deal with heat-induced stress in sea cucumber intestine.展开更多
Sea cucumbers are recognized as food and drug resources with many nutritional benefits, and Apostichopus japonicus is a kind of sea cucumber with good quality. Processing methods have some effect on its quality. This ...Sea cucumbers are recognized as food and drug resources with many nutritional benefits, and Apostichopus japonicus is a kind of sea cucumber with good quality. Processing methods have some effect on its quality. This study aimed to explore the effects of Apostichopus japonicus with three different processing methods (dried, instant, and enzymatic sea cucummbers) on intestinal microflora dysregulation using a cyclophosphamide (cy) induced immunosuppressive mouse model. The expression of lysozyme, immunoglobulin A (IgA), and polymeric immunoglobulin receptor (pIgR) in the intestine and gut microbiota were investigated. The results showed that three types of A. japonicus could improve mucosal immunity and regulate gut microbiota. Dietary A. japonicus could reverse microbial imbalance, including increasing the bacterial diversity, enhancing the number of Bifidobacterium, and changing the bacterial composition. The most effect was observed with dried A. japonicus. Expression of lysozyme and IgA in the intestine was significantly increased. This study identified positive effects of dietary A. japonicus on mucosal immunity, particularly on gut microbiota, suggesting that dietary A. japonicus may aid in improving mucosal immunity and preventing exogenous infection. Additionally, the processing method has some effect on immunomodulatory function.展开更多
Sea cucumber is a food with nutritional benefits distributing mainly in Asia, and Apostichopus japonicus (A. japonicus) is a kind of sea cucumber whose quality is better than any others. However, different processing ...Sea cucumber is a food with nutritional benefits distributing mainly in Asia, and Apostichopus japonicus (A. japonicus) is a kind of sea cucumber whose quality is better than any others. However, different processing methods make various effect on its quality. In this study, we evaluated the protection effect of A. japonicus with different processing methods on mice with ulcerative colitis induced by trinitrobenzene sulfonic acid (TNBS), especially on the intestinal microflora. The expression of IFN-γ/IL-4 and IL-1β in gut, and intestinal microbiota were discussed. The results revealed that three different processing methods of A. japonicus could decrease the expression of inflammatory cytokines, except for the expression of IFN-γ/IL-4 treated with enzymatic, and dried A. japonicus was the most efficient. A. japonicus could change the microbiotic imblance relatively back to normal in terms of bacterial diversity and composition, meanwhile increase the abundance of Bifidobacteria, Lactobacillus and Clostridium leptum. The elements of protein, polysaccharide in dried, instant, enzymatic A. japonicus are 73.09%, 65.06%, 57.42% and 6.72%, 5.46%, 5.45% respectively. This study indicated that A. japonicus have a good improving effect on ulcerative colitis, especially on the microbiome, and processing methods had an effect on alleviation of ulcerative colitis, which might be associated with content of protein and polysaccharide.展开更多
The papilla number is one of the most economically important traits of sea cucumber in the China marketing trade.However,the genetic basis for papilla number diversity in holothurians is still scarce.In the present st...The papilla number is one of the most economically important traits of sea cucumber in the China marketing trade.However,the genetic basis for papilla number diversity in holothurians is still scarce.In the present study,we conducted genomewide association studies(GWAS)for the trait papilla number of sea cucumbers utilizing a set of 400,186 high-quality SNPs derived from 200 sea cucumbers.Two significant trait-associated SNPs that passed Bonferroni correction(P<1.25E−7)were located in the intergenic region near PATS1 and the genic region of EIF4G,which were reported to play a pivotal role in cell growth and proliferation.The fine-mapping regions around the top two lead SNPs provided precise causative loci/genes related to papilla formation and cellular activity,including PPP2R3C,GBP1,and BCAS3.Potential SNPs with P<1E−4 were acquired for the following GO and KEGG enrichment analysis.Moreover,the two lead SNPs were verified in another population of sea cucumber,and the expressive detection of three potential candidate genes PATS1,PPP2R3C,and EIF4G that near or cover the two lead SNPs was conducted in papilla tissue of TG(Top papilla number group)and BG(Bottom papilla number group)by qRT-PCR.We found the significantly higher expression profile of PATS1(3.34-fold),PPP2R3C(4.90-fold),and EIF4G(4.23-fold)in TG,implying their potential function in papilla polymorphism.The present results provide valuable information to decipher the phenotype differences of the papilla trait and will provide a scientific basis for selective breeding in sea cucumbers.展开更多
The Chinese herb Houttuynia cordata Thunb(abbreviated as HCT hereafter)has been widely used in human and livestock medical research.However,few studies have tested the effects of HCT in aquaculture systems,particularl...The Chinese herb Houttuynia cordata Thunb(abbreviated as HCT hereafter)has been widely used in human and livestock medical research.However,few studies have tested the effects of HCT in aquaculture systems,particularly in echinoderms.In this study,the impact of HCT was evaluated when used as a feed additive to enhance the immune response of the sea cucumber,Apostichopus japonicus.Two concentrations,1.5%and 3%,of HCT powder were tested by adding them to the feed.Feeding experiments had a four week duration and each week,the humoral and cellular immunity index of the intestine,tentacles,peristome,and coelomic fluid were analyzed.The results indicated that the percentage of A.japonicus coelomocytes significantly increased after supplementing feed with HCT,and reached a peak after one week of feeding with the 3%HCT supplementation.Analysis of reactive oxygen species(ROS)indicated that HCT in feed caused a notable increase in the coelomocyte ROS concentrations over the experimental period.In both the 1.5%and 3%HCT addition groups,the ROS peaked in the third week and then remained stable.In addition,alkaline phosphatase,acid phosphatase,superoxide dismutase,lysozyme activity of the intestine,tentacles,peristome and coelomic fluid were significantly improved during the four-week test period.In conclusion,1.5%and 3%HCT added to feed boosts the immune responses of A.japonicus.HCT has potential as an immune enhancer for mariculture of sea cucumbers.展开更多
A water flow simulation device capable of adjusting flow velocity was designed in flow velocity range of 0–30 cm/s,with which an indoor experiment was conducted to simulate the movement and adhesive behaviors of diff...A water flow simulation device capable of adjusting flow velocity was designed in flow velocity range of 0–30 cm/s,with which an indoor experiment was conducted to simulate the movement and adhesive behaviors of different-sized Apostichopus japonicus under different flow velocities.Observation showed that,in slow flow(~5 cm/s),A.japonicus moved more distance than in still water,and hardly moved in the riptide(~30 cm/s);and the adhesive capacity of A.japonicus was related to the flow velocity and attachment time.A.japonicus were able to attach to the bottom after any attachment time in the slow flow,after 10 s in the medium flow(~15 cm/s),and after 60 s in the riptide(~30 cm/s).In addition,larger A.japonicus were stronger with adhesive ability than smaller ones.The transcriptome data showed that the expression of transient receptor potential cation channel subfamily A,member 1(TRPA1)in the tube feet was increased significantly in a flowing water,but those in the tentacles and tube feet were not significantly changed.Fluorescence in-situ hybridization results showed that TRPA1 was expressed around the watervascular of tentacles,tube feet,body wall,and spines.Therefore,tube feet were important for sea cucumbers to keep themselves stable in relatively swift flow with adhesion ability.展开更多
基金supported by the National Natural Science Foundation of China (32102825)Natural Science Foundation of Zhejiang Province (LQ22C190003)。
文摘Previous studies have shown that Vibrio splendidus infection causes mitochondrial damage in Apostichopus japonicus coelomocytes,leading to the production of excessive reactive oxygen species(ROS)and irreversible apoptotic cell death.Emerging evidence suggests that mitochondrial autophagy(mitophagy)is the most effective method for eliminating damaged mitochondria and ROS,with choline dehydrogenase(CHDH)identified as a novel mitophagy receptor that can recognize non-ubiquitin damage signals and microtubule-associated protein 1 light chain 3(LC3)in vertebrates.However,the functional role of CHDH in invertebrates is largely unknown.In this study,we observed a significant increase in the mRNA and protein expression levels of A.japonicus CHDH(AjCHDH)in response to V.splendidus infection and lipopolysaccharide(LPS)challenge,consistent with changes in mitophagy under the same conditions.Notably,AjCHDH was localized to the mitochondria rather than the cytosol following V.splendidus infection.Moreover,AjCHDH knockdown using si RNA transfection significantly reduced mitophagy levels,as observed through transmission electron microscopy and confocal microscopy.Further investigation into the molecular mechanisms underlying CHDH-regulated mitophagy showed that AjCHDH lacked an LC3-interacting region(LIR)for direct binding to LC3 but possessed a FB1 structural domain that binds to SQSTM1.The interaction between AjCHDH and SQSTM1 was further confirmed by immunoprecipitation analysis.Furthermore,laser confocal microscopy indicated that SQSTM1 and LC3 were recruited by AjCHDH in coelomocytes and HEK293T cells.In contrast,AjCHDH interference hindered SQSTM1 and LC3 recruitment to the mitochondria,a critical step in damaged mitochondrial degradation.Thus,AjCHDH interference led to a significant increase in both mitochondrial and intracellular ROS,followed by increased apoptosis and decreased coelomocyte survival.Collectively,these findings indicate that AjCHDH-mediated mitophagy plays a crucial role in coelomocyte survival in A.japonicus following V.splendidus infection.
基金The National Natural Science Foundation of China under contract Nos 42276143 and 31902360the Shandong Provincial Natural Science Foundation under contract Nos ZR2022MC050 and ZR2022QD003the“First Class Fishery Discipline”Programme[(2020)3]in Shandong Province。
文摘The sea cucumber Apostichopus japonicus plays important roles in marine benthic ecosystem as environmental cleaners,and it is the important aquaculture species in China.High water temperature poses critical threat for the survival of A.japonicus,which has resulted in extensive death in summer.To explore the genes expression profiles under different levels of heat stress,the high-throughput RNA-seq was applied in this study.Our results revealed a total of 1371,1225 and 1408 differentially expressed genes(DEGs)in 26℃for 6 h,26℃for 48 h and 30℃for 6 h respectively in comparison with Control group.The pathway analysis suggested“Protein processing in endoplasmic reticulum(ER)”was significantly enriched in all these heat stress(HS)treatment groups.The expression results of key DEGs in this pathway(Hsp70,Derlin,NEF,PDI,GPR94 and ERP57)by qRT-PCR was in accordance with the RNA-seq data.The subcluster analysis of DEGs revealed that a variety of heat shock proteins(HSPs)and calcium ion binding proteins had an obvious up-regulated expression in 26℃for 6 h,comparatively low expression in 26℃for 48 h,and the highest expression in 30℃for 6 h.The other DEGs subcluster,consisting of critical components of extracellular matrix(ECM)and a subset of peptidases and proteases,showed significantly rising tendency in 30℃for 6 h.Additionally,the expression of matrix metalloproteases(MMP1,MMP16 and MMP19)was prominently affected by HS,and peaked in 30℃for 6 h.This study provides a series of candidate genes for further study about heat shock response in A.japonicus,especially genes associated with protein processing in ER and regulation of ECM,which also offers new insights into cellular homeostasis under stressful conditions in marine invertebrates.
基金supported by the National Natural Science Foundation of China(No.31672657).
文摘Sea cucumber(Apostichopus japonicus)is an excellent model for investigating effects of bottom-dwellers on carbon mig-ration and transformation.However,the molecular mechanism of respiratory metabolism process variation caused by feeding rations is poorly understood.In this study,treatment groups set as 1%(about 0.63g),3%,and 7%of total body weight(named F1,F3 and F7 groups respectively).The potential molecular mechanisms behind the functions of respiratory tree and body wall were investigated by RNA-Seq.A total of 52411 expressed genes were identified from 89342 expressed transcripts.The results showed 759,254 and 334 genes were up-regulated,and 334,445 and 992 genes were down-regulated in respiratory tree of F1 vs.F3,F1 vs.F7 and F3 vs.F7,respectively.Meanwhile,2070,1601 and 896 genes were up-regulated,and 1303,1337 and 1144 genes were down-regulated in body wall between F1 vs.F3,F1 vs.F7 and F3 vs.F7,respectively.Differentially expressed genes were enriched in salivary secretion and ECM-receptor interaction pathways in respiratory tree,and in various types of N-glycan biosynthesis,ribosome and sphingolipid metabolism pathways in body wall.These results suggested respiratory tree and body wall were involved in activation of respiratory metabolisms in response to different feeding rations.Our research provided valuable knowledge for physiological differences in res-piratory metabolism.
基金supported by the Science and Technology Program of Fujian Province(Nos.2018R1003-1 and 2019R1013-5)the Special Funds for Marine and Fishery Structure Adjustment(No.2020HYJG02)the Marine Economy Innovation and Area Development Demonstration Project of Fujian Province(No.FJHJF-L-2020-4)。
文摘Aestivation is a common strategy of sea cucumbers(Apostichopus japonicus)in response to high-temperature conditions.Previous studies have individually investigated the immune and physiological alterations at the aestivation stage.However,these studies have not evaluated the relationship between immunity and physiology.In this study,we explored the transcriptome and metabolome of A.japonicus during the aestivation stage to study the relationship.The transcriptome analysis of dormant(aestivation)and revived A.japonicus generated 2368 differentially expressed genes,including 927 downregulated genes and 1441 upregulated genes.Based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses,the downregulated genes in the dormant group were found to be involved in DNA replication,RNA metabolic process,and protein metabolism,which results in the inhibition of motility,skeletal development,neural activity,cell proliferation,and development of A.japonicus.In contrast,the upregulated genes were found to be associated with fatty acid metabolism,carbohydrate hydrolysis,and phagocytosis.In the metabolome analysis,the downregulated metabolites were found to be associated with fatty acid metabolism,starch and sucrose metabolism,and TCA cycle.This indicates that dormant sea cucumbers consume reserved carbohydrates and fatty acids to maintain low levels of energy supply.The protein-protein interaction network analysis further revealed that carbohydrate hydrolysis promoted phagocytosis activity in the dormant group.This study provides new insights into potential molecular mechanisms of sea cucumber survival in high-temperature conditions,which is critical in aquaculture of sea cucumbers.
文摘The construction of enrichment library proves to be one of the efficient approaches for isolating microsatellites in this study. The genomic DNA of sea cucumber was digested with HaeIII and size-selected DNA fragments (250-700 bp) were ligated to an adaptor. Microsatellite-containing sequences were captured by using a combination of GA and CA probes, which were attached to a nylon membrane. The microsatellite enrichment library constructed in this study consisted of approximately 700 clones. Two hun-dred and thirty-two clones reacted positively after the library screening procedure. Of the 50 clones sequenced, all contained at least one microsatellite and one duplicate clone was found. Approximately 86% of the sequenced fragments permitted to design primers for sequence tagged microsatellite site (STMS).
基金supported by the National Natural Science Foundation of China(32073003,32102825)Natural Science Foundation of Zhejiang Province(LZ19C190001)+1 种基金Key Project from Science Technology Department of Zhejiang Province(2019R52016)K.C.Wong Magna Fund in Ningbo University。
文摘Organisms produce high levels of reactive oxygen species(ROS)to kill pathogens or act as signaling molecules to induce immune responses;however,excessive ROS can result in cell death.To maintain ROS balance and cell survival,mitophagy selectively eliminates damaged mitochondria via mitophagy receptors in vertebrates.In marine invertebrates,however,mitophagy and its functions remain largely unknown.In the current study,Vibrio splendidus infection damaged mitochondrial morphology in coelomocytes and reduced mitochondrial membrane potential(ΔΨm)and mitophagosome formation.The colocalization of mitochondria and lysosomes further confirmed that lipopolysaccharide(LPS)treatment increased mitophagy flux.To explore the regulatory mechanism of mitophagy,we cloned Bcl2/adenovirus E1 B 19 kDa protein-interacting protein 3(BNIP3),a common mitophagy receptor,from sea cucumber Apostichopus japonicus(Aj BNIP3)and confirmed that Aj BNIP3 was significantly induced and accumulated in mitochondria after V.splendidus infection and LPS exposure.At the mitochondrial membrane,Aj BNIP3 interacts with microtubule-associated protein 1 light chain 3(LC3)on phagophore membranes to mediate mitophagy.After Aj BNIP3 interference,mitophagy flux decreased significantly.Furthermore,Aj BNIP3-mediated mitophagy was activated by ROS following the addition of exogenous hydrogen peroxide(H2 O2),ROS scavengers,and ROS inhibitors.Finally,inhibition of BNIP3-mediated mitophagy by Aj BNIP3 small interfering RNA(si RNA)or high concentrations of lactate increased apoptosis and decreased coelomocyte survival.These findings highlight the essential role of Aj BNIP3 in damaged mitochondrial degradation during mitophagy.This mitophagy activity is required for coelomocyte survival in A.japonicus against V.splendidus infection.
基金Supported by the National Natural Science Foundation of China(No.31772849)the Scientific Research Funding Project of Liaoning Provincial Department of Education in 2019(No.DL201901)the Program for Liaoning Innovative Research Team in University(No.LT2019003)。
文摘Skin ulceration syndrome(SUS)is the main diseases aff ected the development of sea cucumber(Apostichopus japonicus)culture industries.To better observe the changes in the sea cucumber A.japonicus with SUS and understand the pathogenesis of the disease,activities of superoxide dismutase(SOD),catalase(CAT),and level of malondialdehyde(MDA)in coelomic fluid were detected using the Assay Kit and metabolites in the body wall were assessed using ultra-performance liquid chromatography and quadrupole-time of flight mass spectrometry.The results indicated that level of MDA was increased during SUS compared with healthy individuals(P<0.01),but activities of SOD and CAT were reduced(P<0.05).In metabolomics analysis,metabolites,such as adenosine,choline,betaine aldehyde,palmitic acid,and taurine,were found to be upregulated and 2-oxoadipic acid,anthranilic acid(vitamin L1),thioetheramide-PC,cholesterol-3-sulfate,and pentadecanoic acid were downregulated(VIP>1 and P<0.1).Pathway enrichment analysis indicated most enrichment of KEGG pathways were mainly related to energy metabolism,immunity,and osmoregulation such as ABC transporters,glycine,serine and threonine metabolism,tryptophan metabolism and neuroactive ligand-receptor interaction.Our study reflected the difference in enzyme activity and metabolites between A.japonicus with SUS and those without,which will provide reference data for investigating SUS.
基金funded by the National Natural Science Foundation of China (Nos. 31172426 and 31372549)Ministry of Science and Technology of China (Nos. 2011BAD13B03 and 2012GA740001)supported by the Program for New Century Excellent Talents in University (NCET-11-0466)
文摘Monoculture of sea cucumber(pond S) and polyculture of shrimp with sea cucumber(pond SS) were established to evaluate the effect of shrimp on the environmental conditions of sea cucumber farming pond. Contributions of sediment organic matter(SOM2) resuspended from benthic sediment and the suspended particulate organic matter(SPOM) deposited from the water column to the precipitated organic matter(SOM1) collected with sediment traps were estimated with carbon stable isotope analysis. The results showed that the levels of SPOM and SOM2 in pond SS significantly decreased in comparison with those in pond S at the end of experiment(P < 0.05), indicating that co-culturing shrimp in sea cucumber farming pond could purify the farming water. Carbon stable isotope analysis showed that the proportion of SOM2 in SOM1 in pond SS(84.97% ± 0.38%) was significantly lower than that in pond S(95.20% ± 0.30%)(P < 0.05), suggesting that the resuspension of organic matter from benthic sediment into overlying water was reduced in polyculture pond. In contrast, the proportion of SPOM in SOM1 in pond SS(15.03% ± 0.38%) was significantly higher than that in pond S(4.80% ± 0.30%)(P < 0.05), indicating that the sedimentation of SPOM from water column was enhanced in pond SS owing to the biodeposition effect of shrimp.
基金supported by the National Key R&D Program of China(No.2018YFD0900105)the Entrepre-neurship Program for High-Level Talent of Dalian(No.2018RD10)+1 种基金the Liaoning Revitalization Talents Program(No.XLYC1907109)the Liaoning Key Research and Development Program(No.2018228004).
文摘Apostichopus japonicus is an important invertebrate that is widely used as a tonic food in Asian countries.The purpose of this study is to purify and identify a class of compound,the saponins,from the body wall of A.japonicus,and to establish a new me-thod to determine the quantity of saponins in the sea cucumber.In this study,the saponins of A.japonicus,cladoloside A(CA),were ob-tained from 80%ethanol extract by column chromatography for the first time and were characterized using the spectral method.The resulting purified saponins were then profiled using ^(1)HNMR,^(13)CNMR,and ESI-MS,which revealed the CA molecular formula of C_(53)H_(82)O_(2) and contained a triterpenoid backbone,a methylglucopyranosyl moiety,a quinovopyranosyl,and two xylopyranosyls.A me-thod for the quantitative determination of CA,comprising microwave-assisted extraction,high-performance liquid chromatography,and diode array detector method,was established.Extraction efficiency was optimized by changing microwave power,extraction sol-vent,volume,time,and temperature.Results showed that under the optimum conditions(extraction time of 10 min,temperature of 45℃,and solvent of 25 mL 70%ethanol under 400 W),the detection limit of CA was 0.0015 mg mL^(−1),and the recoveries of CA from samples at spiking levels of 10,20,and 50μg g^(−1) ranged from 90.1%-104%.The proposed method was successfully applied to ana-lyze the saponins in different tissues of A.japonicus collected in different seasons.The method developed in this study can provide quantitative technical support for the quality control of A.japonicus.
基金funded by the National Natural Science Foundation of China (Nos.31172426 and 31372549)the Ministry of Science and Technology of China (No.2011BAD13B03)
文摘The present study was conducted to determine the change of digestive physiology in sea cucumber Apostichopus japonicus(Selenka) induced by corn kernels meal and soybean meal in diets. Four experimental diets were tested, in which Sargassum thunbergii was proportionally replaced by the mixture of corn kernels meal and soybean meal. The growth performance, body composition and intestinal digestive enzyme activities in A. japonicus fed these 4 diets were examined. Results showed that the sea cucumber exhibited the maximum growth rate when 20% of S. thunbergii in the diet was replaced by corn kernels meal and soybean meal, while 40% of S. thunbergii in the diet can be replaced by the mixture of corn kernels meal and soybean meal without adversely affecting growth performance of A. japonicus. The activities of intestinal trypsin and amylase in A. japonicus can be significantly altered by corn kernels meal and soybean meal in diets. Trypsin activity in the intestine of A. japonicus significantly increased in the treatment groups compared to the control, suggesting that the supplement of corn kernels meal and soybean meal in the diets might increase the intestinal trypsin activity of A. japonicus. However, amylase activity in the intestine of A. japonicus remarkably decreased with the increasing replacement level of S. thunbergii by the mixture of corn kernels meal and soybean meal, suggesting that supplement of corn kernels meal and soybean meal in the diets might decrease the intestinal amylase activity of A. japonicus.
基金financially supported by the National Natural Science Foundation of China(No.31802331)the Natural Science Foundation of Zhejiang Province(Nos.LZ19C190001,LY20C190002)+1 种基金the Natural Science Foundation of Ningbo(No.2018A610340)the K.C.Wong Magna Fund in Ningbo University。
文摘F-type lectins(Fucolectins)are carbohydrate-binding proteins and play important roles in innate immune responses against pathogenic microbial invasion.In our previous research,we found that two homologous Fucolectin genes,AjFTL-1 and AjFTL-2,exhibited different expression profiles after lipopolysaccharides(LPS)challenge in Apostichopus japonicus.However,the transcriptional regulation mechanism of these two genes remains largely unknown.In this study,the 5'flanking regions of Aj FTL-1 and Aj FTL-2 genes were cloned and the promoter activities were studied in epithelioma papulosum cyprinid(EPC)cell system.First,in silico analysis indicated that these two promoters both contain numerous putative transcription factor binding sites including NF-κB,CREB,and CREBP1,and both contain a TATA box.Additionally,luciferase assay and progressive 5'truncation analysis revealed that AjFTL-1 and AjFTL-2 both possess high promoter activities in EPC cells.Moreover,the luciferase activity of AjFTL-1 promoter was significantly regulated by peptidoglycan(PGN)and mannan(MAN),while AjFTL-2 promoter was prominently regulated by LPS and MAN,indicating Aj FTL-1 and Aj FTL-2 genes showed different transcriptional regulation pattern under different immune stimulation.More importantly,analyses of the functional promoter regions revealed the presence of two potential NF-κB binding sites(-769 bp to-761 bp,-185 bp to-172 bp)in Aj FTL-1 and one potential binding site(-530 to-517 bp)in Aj FTL-2.Different truncated reporter vectors and expression vector co-transfection revealed that transcription factor NF-κB/Rel could significantly increase the AjFTL-2 promoter activity,but not AjFTL-1 promoter activity.These findings indicated that in marine invertebrates,different Fucolectin members differ in transcription regulations and expression patterns,and might play different roles in immune defenses during pathogen infection.
基金Supported by the National Natural Science Foundation of China(No.41676124)。
文摘Abstract The unfolded protein response(UPR)is an important protective and compensatory strategy used during endoplasmic reticulum stress caused by factors including glucose starvation,low pH,or heat shock.However,there is very little information on the possible role(s)of the UPR under adverse conditions experienced by marine invertebrates.We observed that rough endoplasmic reticulum(ER)was dramatically expanded and numerous autophagosomes were accumulated in the intestinal cells of sea cucumbers,Apostichopus japonicus,under heat stress(4 h at 25°C compared with 15°C controls).Moreover,heat stress led to sharp increases in the relative transcript and protein expression levels of two primary ER chaperones:the endoplasmic reticulum resident protein 29-like(ERP29)and protein disulfi de-isomerase A6-like(PDIA6).These results suggest a potential adaptive mechanism to deal with heat-induced stress in sea cucumber intestine.
文摘Sea cucumbers are recognized as food and drug resources with many nutritional benefits, and Apostichopus japonicus is a kind of sea cucumber with good quality. Processing methods have some effect on its quality. This study aimed to explore the effects of Apostichopus japonicus with three different processing methods (dried, instant, and enzymatic sea cucummbers) on intestinal microflora dysregulation using a cyclophosphamide (cy) induced immunosuppressive mouse model. The expression of lysozyme, immunoglobulin A (IgA), and polymeric immunoglobulin receptor (pIgR) in the intestine and gut microbiota were investigated. The results showed that three types of A. japonicus could improve mucosal immunity and regulate gut microbiota. Dietary A. japonicus could reverse microbial imbalance, including increasing the bacterial diversity, enhancing the number of Bifidobacterium, and changing the bacterial composition. The most effect was observed with dried A. japonicus. Expression of lysozyme and IgA in the intestine was significantly increased. This study identified positive effects of dietary A. japonicus on mucosal immunity, particularly on gut microbiota, suggesting that dietary A. japonicus may aid in improving mucosal immunity and preventing exogenous infection. Additionally, the processing method has some effect on immunomodulatory function.
文摘Sea cucumber is a food with nutritional benefits distributing mainly in Asia, and Apostichopus japonicus (A. japonicus) is a kind of sea cucumber whose quality is better than any others. However, different processing methods make various effect on its quality. In this study, we evaluated the protection effect of A. japonicus with different processing methods on mice with ulcerative colitis induced by trinitrobenzene sulfonic acid (TNBS), especially on the intestinal microflora. The expression of IFN-γ/IL-4 and IL-1β in gut, and intestinal microbiota were discussed. The results revealed that three different processing methods of A. japonicus could decrease the expression of inflammatory cytokines, except for the expression of IFN-γ/IL-4 treated with enzymatic, and dried A. japonicus was the most efficient. A. japonicus could change the microbiotic imblance relatively back to normal in terms of bacterial diversity and composition, meanwhile increase the abundance of Bifidobacteria, Lactobacillus and Clostridium leptum. The elements of protein, polysaccharide in dried, instant, enzymatic A. japonicus are 73.09%, 65.06%, 57.42% and 6.72%, 5.46%, 5.45% respectively. This study indicated that A. japonicus have a good improving effect on ulcerative colitis, especially on the microbiome, and processing methods had an effect on alleviation of ulcerative colitis, which might be associated with content of protein and polysaccharide.
基金the National Key Research and Development Program of China(2018YFD0901601)National Natural Science Foundation of China(32072976)Sanya Yazhou Bay Science and Technology City(SKJC-KJ-2019KY01).
文摘The papilla number is one of the most economically important traits of sea cucumber in the China marketing trade.However,the genetic basis for papilla number diversity in holothurians is still scarce.In the present study,we conducted genomewide association studies(GWAS)for the trait papilla number of sea cucumbers utilizing a set of 400,186 high-quality SNPs derived from 200 sea cucumbers.Two significant trait-associated SNPs that passed Bonferroni correction(P<1.25E−7)were located in the intergenic region near PATS1 and the genic region of EIF4G,which were reported to play a pivotal role in cell growth and proliferation.The fine-mapping regions around the top two lead SNPs provided precise causative loci/genes related to papilla formation and cellular activity,including PPP2R3C,GBP1,and BCAS3.Potential SNPs with P<1E−4 were acquired for the following GO and KEGG enrichment analysis.Moreover,the two lead SNPs were verified in another population of sea cucumber,and the expressive detection of three potential candidate genes PATS1,PPP2R3C,and EIF4G that near or cover the two lead SNPs was conducted in papilla tissue of TG(Top papilla number group)and BG(Bottom papilla number group)by qRT-PCR.We found the significantly higher expression profile of PATS1(3.34-fold),PPP2R3C(4.90-fold),and EIF4G(4.23-fold)in TG,implying their potential function in papilla polymorphism.The present results provide valuable information to decipher the phenotype differences of the papilla trait and will provide a scientific basis for selective breeding in sea cucumbers.
基金This work was funded in part by the State Key Research Project"Marine environment safety"(2017YFC1404503)General Scientific Research Project of Education Department in Liaoning Province(L2015077)+1 种基金Doctoral Research Project of Science and Technology Department program in in Liaoning Province(201601287)Doctoral Research Project of Dalian Ocean University(HDYJ201617).
文摘The Chinese herb Houttuynia cordata Thunb(abbreviated as HCT hereafter)has been widely used in human and livestock medical research.However,few studies have tested the effects of HCT in aquaculture systems,particularly in echinoderms.In this study,the impact of HCT was evaluated when used as a feed additive to enhance the immune response of the sea cucumber,Apostichopus japonicus.Two concentrations,1.5%and 3%,of HCT powder were tested by adding them to the feed.Feeding experiments had a four week duration and each week,the humoral and cellular immunity index of the intestine,tentacles,peristome,and coelomic fluid were analyzed.The results indicated that the percentage of A.japonicus coelomocytes significantly increased after supplementing feed with HCT,and reached a peak after one week of feeding with the 3%HCT supplementation.Analysis of reactive oxygen species(ROS)indicated that HCT in feed caused a notable increase in the coelomocyte ROS concentrations over the experimental period.In both the 1.5%and 3%HCT addition groups,the ROS peaked in the third week and then remained stable.In addition,alkaline phosphatase,acid phosphatase,superoxide dismutase,lysozyme activity of the intestine,tentacles,peristome and coelomic fluid were significantly improved during the four-week test period.In conclusion,1.5%and 3%HCT added to feed boosts the immune responses of A.japonicus.HCT has potential as an immune enhancer for mariculture of sea cucumbers.
基金the National Key R&D Program of China(No.2019YFD0900800)the National Science Foundation for Young Scientists of China(No.41606171)+1 种基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2018SDKJ0502)the Science and Technology Service Network Program of Chinese Academy of Sciences(No.KFJ-STS-ZDTP-55)。
文摘A water flow simulation device capable of adjusting flow velocity was designed in flow velocity range of 0–30 cm/s,with which an indoor experiment was conducted to simulate the movement and adhesive behaviors of different-sized Apostichopus japonicus under different flow velocities.Observation showed that,in slow flow(~5 cm/s),A.japonicus moved more distance than in still water,and hardly moved in the riptide(~30 cm/s);and the adhesive capacity of A.japonicus was related to the flow velocity and attachment time.A.japonicus were able to attach to the bottom after any attachment time in the slow flow,after 10 s in the medium flow(~15 cm/s),and after 60 s in the riptide(~30 cm/s).In addition,larger A.japonicus were stronger with adhesive ability than smaller ones.The transcriptome data showed that the expression of transient receptor potential cation channel subfamily A,member 1(TRPA1)in the tube feet was increased significantly in a flowing water,but those in the tentacles and tube feet were not significantly changed.Fluorescence in-situ hybridization results showed that TRPA1 was expressed around the watervascular of tentacles,tube feet,body wall,and spines.Therefore,tube feet were important for sea cucumbers to keep themselves stable in relatively swift flow with adhesion ability.
