Transcriptomic response to ammonia-N stress in the hepatopancreas of swimming crab Portunus trituberculatus

The swimming crab Portunus trituberculatus is an important farmed species in China.Ammonia-N represents a major physiological challenge for crab culture and the hepatopancreas plays a major role in physiological adaptation processes.To better understand the molecular mechanism of the crab in response to ammonia-N stress,we performed a transcriptome analysis in the hepatopancreas of P.trituberculatus challenged with ammonia-N stress(5 mg/L),using the high-throughput sequencing technology.In total,52,280 unigenes were obtained from the hepatopancreas of P.trituberculatus,with an average length of 678 bp.Functional categorization and pathways showed some diiferentially expressed genes were involved in amino acid and nucleobase metabolism,energy metabolism,antioxidation,immune response,reproduction,moulting and material transport.The differential expression patterns of eight randomly selected annotated genes were validated by quantitative real-time PCR(qPCR).Results revealed a substantial number of genes modified by ammonia-N stress and a few significant ammonia acclimation pathways,which will serve as an invaluable resource for revealing the molecular basis of physiological adaptation mechanism in P.trituberculatus.

Integration of chemical and biological methods:A case study of polycyclic aromatic hydrocarbons pollution monitoring in Shandong Peninsula,China

Polycyclic aromatic hydrocarbons(PAHs),as persistent toxic substances(PTS),have been widely monitored in coastal environment,including seawater and sediment.However,scientific monitoring methods,like ecological risk assessment and integrated biomarker response,still need massive researches to verify their availabilities.This study was performed in March,May,August and October of 2018 at eight sites,Yellow River estuary(S1),Guangli Port(S2),Xiaying(S3),Laizhou(S4),Inner Bay(S5),Outer Bay(S6),Hongdao(S7)and Hongshiya(S8)of Shandong Peninsula,China.The contents of 16 priority PAHs in local seawater and sediment were determined,by which ecological risk assessment risk quotient(RQ)for seawater and sediment quality guidelines(SQGs)were calculated to characterize the PAHs pollution.Meanwhile,multiple biomarkers in the digestive gland of clam Ruditapes philippinarum were measured to represent different biological endpoints,including ethoxyresorufin-O-deethylase(EROD),glutathione S-transferase(GST),sulfotransferase(SULT),superoxide dismutase(SOD)and lipid peroxidation(LPO),by which integrated biomarker response(IBR)was calculated to provide a comprehensive assessment of environmental quality.Taken together,these results revealed the heaviest pollution at S2 as both PAHs concentrations and biomarkers responses reflected,and supported the integrated biomarker response as a useful tool for marine environmental monitoring,through its integration with SQGs.

Bioaccumulation and function analysis of glutathione S-transferase isoforms in Manila clam Ruditapes philippinarum exposed to different kinds of PAHs

This study analyzed the function of different glutathione S-transferase(GST)isoforms and detoxification metabolism responses in Manila clam,Ruditapes philippinarum,exposed to 4 kinds of polycyclic aromatic hydrocarbons(PAHs)single,and their mixtures for 15 days under laboratory conditions.13 kinds of GSTs in R.philippinarum were classified,and the results of tissue distribution indicated that 12 kinds of GSTs(except GST sigma 3)expressed most in digestive glands.We detected the m RNA expression levels of aryl hydrocarbon receptor signaling pathway,and detoxification system in digestive glands of clams exposed to benzo[a]pyrene(Ba P),chrysene(CHR),benzo[a]anthracene(Ba A),benzo[b]fluoranthene(Bb F),and Ba P+CHR+Ba A+Bb F,respectively.Among these genes,we selected GST-sigma,GST-omega and GST-pi as potential indicators to Ba P;GST-sigma,GST-A and GST-rho to CHR;GST-pi,GST-sigma,GST-A,GST-rho and GST-microsomal to Ba A;GST-theta and GST-mu to Bb F;while GST-pi and GST-mu to the mixture of Ba P,CHR,Ba A and Bb F.Additionally,the bioaccumulation of PAHs in tissues increased remarkably over time,and showed an obvious doseeffect.Under the same concentration,the bioaccumulation in single exposure group was higher than that in mixture group,and the bioaccumulation of PAHs in tissues with different concentrations of stress was irregular.The results revealed the metabolic differences and bioaccumulation rules in clams exposed to four kinds of PAHs,and provided more valuable information for the PAHs risk assessment.