Effects of methyl parathion on Chasmagnathus granulatus hepatopancreas: protective role of sesamol

Effects of saline-alkali stress on the tissue structure, antioxidation, immunocompetence and metabolomics of Eriocheir sinensis

Saline-alkali water resources are abundant and widely distributed in China. The effective utilization of saline-alkali water resources by fishery is of great significance to enhance the aquatic product economy and restore the ecology of saline-alkali environments. Eriocheir sinensis is a saline-alkali water-suitable species. To explore its physiological response to saline-alkali stress, the hepatopancreas tissue structure, antioxidation, immunocompetence and metabolomics were investigated after 96 h of gradient saline-alkali treatment. The results confirmed the hepatopancreas damage through tissue sectioning, abnormal enzyme activity (aspartate transaminase (AST), alanine aminotransferase (ALT)) and aberrant malondialdehyde (MDA) content. The activity of superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (T-AOC) was significantly upregulated (p < 0.05), which was followed by a decrease trend, indicating the enhancement of antioxidant capacity in response to the stress. Strengthened immunocompetence in response to saline-alkali toxicity was shown in the gradual increase of immune enzyme activity (acid phosphatase (ACP) and alkaline phosphatase (AKP)) and the upregulated expression of immune genes (hsp 70, hsp 90, proPO and toll). Among the differential metabolites quantified by metabolomics, small peptides were significantly downregulated (p < 0.05), and acylcarnitines were obviously upregulated (p < 0.05), indicating that saline-alkali toxicity inhibited protein catabolism and stimulated the mobilization of energy reserves. Metabolic pathways enriched through the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that Eriocheir sinensis activated different mechanisms in response to various degrees of stress, such as "ABC transporters" and "purine metabolism" in response to low saline-alkali stress, while "pyrimidine metabolism" and "beta-alanine metabolism" to high saline-alkali stress.

A new insight to characterize immunomodulation based on hepatopancreatic transcriptome and humoral immune factor analysis of the Cherax quadricarinatus infected with Aeromonas veronii

Cherax quadricarinatus is a type of large freshwater crayfish that is characterized by rapid growth and formidable adaptability. It has also been widely cultured and studied as a model organism. Aeromonas veronii is the dominant pathogen in aquatic environments and the primary threat to aquaculture's economic stability. To better understand the interactions between C. quadricarinatus and A. veronii, high-throughput RNA sequencing of the C. quadricarinatus hepatopancreas was carried out on a control group, susceptible group (6 h after infection), and resistant group (48 h after infection). A total of 65,850,929 genes were obtained. Compared with the control group, 2616 genes were up-regulated and 1551 genes were down-regulated in the susceptible group; while 1488 genes were up-regulated and 1712 genes were down-regulated in the resistant group. GO and KEGG analysis showed that these differentially expressed genes (DEGs) were associated with multiple immune pathways, including Toll-like receptors (TLRs), antigen processing and presentation, NOD-like receptor signaling pathway, phagosome, lysosome, JAK-STAT signaling pathway. qRT-PCR showed that infection by A. veronii changed the expression pattern of the serine proteinase inhibitor (SPI), crustacean hyperglycemic hormone (CHH), anti-lipopolysaccharide factor (ALF), and extracellular copper/zinc superoxide dismutase (SOD1), all of which were significantly higher than in the control group up to 48 h after infection. In addition, detection of superoxide dismutase (SOD), catalase (CAT), lysozyme (LZM), and phenoloxidase (PO) activity, as well as ceruloplasmin (CP) concentration at different times after infection showed diverse trends. Furthermore, pathological sections obtained 24 h after infection show lesions on the hepatopancreas and intestinal tissues caused by A. veronii. The results of this study provide a foundation for analyzing the immune mechanism of C. quadricarinatus infected with A. veronii at the transcriptional level and a theoretical basis for screening disease-resistant individuals to ensure healthy economic development of the aquatic industry.

Effects of chlorpyrifos on the crustacean Litopenaeus vannamei

Shrimps can be used as indicators of the quality of aquatic systems exposed to a variety of pollutants. Chlorpyrifos is one of the most common pesticides found in environmental samples. In order to evaluate the effects of chlorpyrifos, adult organisms of Litopenaeus vannamei were exposed to two sublethal concentrations of the pesticide (0.7 and 1.3 μg/L) for four days. The LC₅₀ (96-hours) value was determined and Lipid oxidation levels (LPO) and the activities of catalase (CAT), glutathion peroxidase (GPx), glutathion-S-transferase (GST) were assessed on the muscle, hepatopancreas and gills from the exposed organisms. In addition, inhibition of acetylcholinesterase (AChE) was determined in the brain. LC₅₀ (96-hours) was 2.10 μg/L of chlorpyrifos. Catalase activity and LPO were elevated in the three tissues, whereas a decrease of AChE activities in the brain and an increase of GST activity in the hepatopancreas were observed.

Transcriptomic responses of the clam Meretrix meretrix to the organophosphorus pesticide (dimethoate)

Organophosphorus pesticides (OPs) play a certain role in promoting the development of agriculture and forestry, but they may cause potential harm to aquatic life when entering rivers and polluting water sources. Previous researches have shown that OPs participate in the regulation mechanism of aquatic organisms. Here, our aim is to determine the underlying mechanisms of one OP (dimethoate) at the transcriptional level using the clam Meretrix meretrix. 4119 DEGs were obtained from high-throughput RNA sequencing data. Then, expression profiles of some genes were verified by qPCR, which showed a positive correlation with the RNA sequencing results. 14,481 simple sequence repeats were also identified and could be further used as molecular markers. In addition, some oxidative, immune, and stress-related genes were further discussed and could also be used as biomarkers to indicate the biological response of dimethoate. This study will help to better understand the clam's response mechanism to dimethoate stress.

Identification and functional analysis of inhibitor of NF-κB kinase (IKK) from Scylla paramamosain: The first evidence of three IKKs in crab species and their expression profiles under biotic and abiotic stresses

IKK (inhibitor of NF-κB kinase) is the critical regulator for NF-κB (nuclear factor-κB) pathway against pathogenic invasion in vertebrates or invertebrates. However, the IKK from crab species has not yet been identified. In the present study, three full-length cDNA sequences of IKKs from mud crab Scylla paramamosain, designated as SpIKKβ, SpIKKε1 and SpIKKε2, were firstly cloned through RT-PCR and RACE methods. This is also the first report about the identification of two IKKε genes in mud crab and even in crustaceans. The SpIKKβ cDNA was 2824 bp in length with an open reading frame (ORF) of 2382 bp, which encoded a putative protein of 793 amino acids (aa). The ORF of two SpIKKε isoforms, SpIKKε1 and SpIKKε2, were 2400 bp and 2331 bp in length encoding 799 aa and 776 aa, respectively. The crucial conserved residues and functional domains, including the kinase domains (KDs) and leucine zipper (LZ), were identified in all SpIKKs. Phylogenetic analysis suggested that SpIKKβ was classified into the IKKs class while SpIKKεs could be grouped into the IKK-related kinases class. The qRT-PCR analysis showed that three SpIKKs were constitutively expressed in all tested tissues and the highest expression levels of SpIKKβ and SpIKKεs were all in hemocyte. The gene expression profiles of SpIKKs were distinct when crabs suffered biotic and abiotic stresses including the exposures of Vibrio alginolyticus, poly (I:C), cadmium and air exposure, suggesting that the SpIKKs might play different roles in response to pathogens infections, heavy metal and air exposure. Moreover, IKKs from mud crab can significantly activate mammalian NF-κB pathway, suggesting the function of IKKs might be evolutionally well-conserved. Results of the RNAi experiments suggested that SpIKKs might regulate the immune signaling pathway when hemocytes were challenged with V. parahemolyticus or virus-analog poly (I:C). All of these results indicated that the obtained SpIKKs might be involved in stress responses against biotic or abiotic stresses, and it also highlighted their functional conservation in the innate immune system from crustaceans to mammals.

A comparative study on oxidative stress response in the hepatopancreas and midgut of the white shrimp Litopenaeus vannamei under gradual changes to low or high pH environment

White shrimp Litopenaeus vannamei were reared under conditions of gradual changes to a low pH (gradual-low pH, 6.65-8.20) or a high pH (gradual-high pH, 8.20-9.81) versus a normal pH environment (8.14-8.31) during a 28-day period. Survival of shrimp, and ROS production, antioxidant responses and oxidative damage in the hepatopancreas and midgut were investigated. Consequently, shrimp enhanced MnSOD, GPx, and Hsp70 transcripts as early defense mechanism in the hepatopancreas and midgut to scavenge excessive ROS during short-term (≤ 7 days) gradual-low and high pH stress. Meanwhile, the hepatopancreas was more sensitive to ROS than midgut because of earlier ROS production increase, antioxidant response and oxidative damage. Then, suppressed antioxidant response in the hepatopancreas and midgut of shrimp suggested a loss of antioxidant regulatory capacity caused by aggravated oxidative damage after long-term (≥ 14 days) gradual-high pH stress, leading to continuous death. However, enhanced GPx, GST, and Hsp70 transcripts in the hepatopancreas and midgut might be long-term(≥ 14 days) antioxidant adaptation mechanism of shrimp to gradual-low pH stress, which could prevent further ROS perturbation and weaken oxidative damage to achieve a new immune homeostasis, contributing to stable survival rate. Therefore, we have a few insights that it is necessary to protect hepatopancreas for controlling shrimp death under gradual-high pH stress.

The comprehensive expression analysis of the G protein-coupled receptor from Penaeus monodon indicating it participates in innate immunity and anti-ammonia nitrogen stress

The G protein-coupled receptors (GPCRs) composed a superfamily that played an important role in physiological processes of crustaceans, with multiple functions such as growth and development, acting as a defense against stimulations from external factors. In this paper, one kind of GPCRs were identified from Penaeus monodon, called PmGPCR, included an open reading frame (ORF) of 1113 bp. Bioinformatic analysis showed that PmGPCR protein had the typical structure of seven transmembrane domains (7TM), especially the special Asp-Arg-Try motif (DRY motif) between the third transmembrane structures (TM3) and the second intracellular loops (IL-2) which can prove that PmGPCR belongs to the rhodopsin-like family. The analyses of phylogenetic tree indicated that the amino acid sequence of PmGPCR should be merged into Procambarus clarkiic with high identity (98%). Quantitative real-time PCR (q RT-PCR) revealed that PmGPCR mRNA was highly expressed in hepatopancreas, abdominal ganglia and lymph, in which it was significantly higher than that of other tissues (P < 0.05). In addition, the expression of PmGPCR was analyzed during three days post-stimulation with the gram-positive/negative bacteria, the mRNA expression level increased after challenged with gram - positive bacteria in hepatopancreas, lymph and intestines. During the development stages, PmGPCR showed significantly higher expression in nauplius, zoea III, mysis III and post larvae stages than that in other development stages. Meanwhile, the highest transcripts expression of PmGPCR in abdominal ganglia, hepatopancreas, lymph and intestines respectively appeared at D0, D1, D2 and D3/D4 stages of molting. High or low concentration of ammonia nitrogen up-regulated the expression level of PmGPCR at the initial stage in hepatopancreas and gill, and then down-regulated at 48 h. These results indicated PmGPCR may mediate the pathways that involved in growth and development process, survival in the adversity, in addition, provided the useful data to research GPCR-mediated physiological and biological process and explain the mechanisms to defense pathogens and anti-stress in shrimp.

Histopathological effects of chlorpyrifos on the gills, hepatopancreas and gonads of the freshwater crab Zilchiopsis collastinensis. Persistent effects after exposure

Sublethal effects of the pesticide chlorpyrifos were evaluated in the crab Zilchiopsis collastinensis (Decapoda, Trichodactylidae). Crabs were exposed to high concentrations of chlorpyrifos at the beginning of the experiment and controlled dilution, under natural light and temperature conditions. A control and three concentrations (22.4, 41.25 and 61.4µg chlorpyrifos L^-1) were evaluated in triplicate. Nine crabs per concentration and day were used. The gills, hepatopancreas and ovaries were sampled before pesticide exposure (day 0) and 8, 15 and 22 days later, when concentrations were diluted and below the detection limits. The histopathological effects and their variations in time were observed and quantified. In gills, hyperplasias were observed in several cases, mainly in crabs exposed to chlorpyrifos. The number of collapsed lamellae and the number of affected lamellae quickly increased in exposed crabs, as effects were observed on day 8 and remained until day 22. In hepatopancreas there was an increase in the number of F and B -cells and affected tubules, especially after 22 days of exposure (p<0.05). In ovaries, there were no effects on gonadosomatic indexes or oocyte volume, but there was a significant increase in the atretic oocyte proportion related to pesticide exposure (p<0.05). The histopathological effects on the gills, hepatopancreas and ovaries were observed after exposure and persist even after dilution, and might be related to earlier exposures. Thus, these histopathological effects might be used as pesticide biomarkers even after the pesticide is not detected by chemical methods.

Effect of desiccation and resubmersion on the oxidative stress response of the kuruma shrimp Marsupenaeus japonicus

In the present study, the oxidative stress response in hepatopancreas of Marsupenaeus japonicus to desiccation stress and resubmersed in seawater were studied, such as respiratory burst, ROS production ( [Formula: see text] ), activities of antioxidant enzymes (CAT, GPx, SOD, POD and GST) and oxidative damage to lipid and protein (indexed by contents of MDA). The duration of desiccation significantly influenced shrimp survival, and the mortality rates were 37.5% and 87.5% after desiccation 5 h and 10 h, respectively. After desiccation stress 3 h, the respiratory burst, ROS production, and the activity of SOD and CAT were up-regulated significantly. The activity of GPx and POD, and the content of MDA decreased significantly at 0.5 h and 1 h, and then increased significantly at 3 h. But GST activity was no significant change after desiccation. During the resubmersion period, most of the antioxidant enzymes activities could recover to the control level at 24 h, but a small quantity of the oxidative stress still existed in tissues. HE staining showed that desiccation stress induced damage symptoms in hepatopancreas of M. japonicus. These results revealed that desiccation influenced the antioxidative status and caused oxidative stress and tissue damage via confusion of antioxidant enzymes in M. japonicus, but the oxidative stress could be eliminated within a certain range after the shrimps were resubmersed in seawater.

Oxidative stress response of the black tiger shrimp Penaeus monodon to Vibrio parahaemolyticus challenge

Vibrio parahaemolyticus is a virulent pathogen that affects shrimp aquaculture. Reactive oxygen species are produced by the immune system that defends the host against foreign microorganisms. In the present study, the oxidative stress response in hepatopancreas and gills of Penaeus monodon to V. parahaemolyticus challenge were studied, such as respiratory burst, ROS production (·O2(-) and ·OH), activities of antioxidant enzymes (CAT, GPx, SOD, POD and GST) and oxidative damage to lipid and protein (indexed by contents of MDA). Compared with the control group, after V. parahaemolyticus challenge, respiratory burst and ROS production were up-regulated significantly. GPx and POD activity increased significantly in hepatopancreas and gills of the shrimps at 12 h, but CAT activity decreased markedly at 12 h and 24 h. SOD and GST activity in hepatopancreas of the shrimps increased significantly at 1.5 h, but decreased markedly at 12 h-48 h. MDA content increased significantly after 6 h-24 h challenge. HE staining showed that V. parahaemolyticus challenge induced damage symptoms in hepatopancreas of P. monodon. Our study revealed that V. parahaemolyticus influenced the antioxidative status and caused oxidative stress and tissue damage via confusion of antioxidant enzymes in P. monodon.

Cloning and characterization of calreticulin and its association with salinity stress in P. trituberculatus

Calreticulin (CRT) is a highly conserved and multifunctional endoplasmic reticulum (ER) chaperone protein and plays important roles in salinity stress response. Portunus trituberculatus is a commercially important fishery species, and water salinity conditions influence its commercial farming significantly. In order to research the function of calreticulin under salinity stress, the full-length cDNA sequence of calreticulin from P. trituberculatus (PtCRT) was firstly cloned and characterized. The complete cDNA sequence of PtCRT is 1676 bp with 1218 bp open reading frame (ORF), encoding a polypeptide of 405 amino acids. Multiple sequence alignments showed that the deduced acid amino sequences of PtCRT shared the highest homology to CRT of Fenneropenaeus chinensis (89%). Fluorescent quantitative real-time PCR analysis indicated that PtCRT was expressed in all detected tissues and showed the highest expression level in hepatopancreas. In addition, salinity challenge significantly influenced the expression level of PtCRT in gill. Six single nucleotide polymorphisms (SNPs) were detected in cDNA sequence of PtCRT, and one SNP was associated with the salt tolerant trait. All results indicated that PtCRT plays an important role in mediating the salinity adaption of P. trituberculatus.

Acute toxicity of organophosphate fenitrothion on biomarkers in prawn Palaemonetes argentinus (Crustacea: Palaemonidae)

The effect of the organophosphate fenitrothion (FS) on the non-target freshwater prawn Palaemonetes argentinus was studied. Initially, the 96-h lethal concentration (LC50) of FS was determined in adult prawns. Inhibition of cholinesterase (ChE) in the muscle and hemolymph was assessed. Then, in the hepatopancreas, the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) were analyzed. Lipid peroxidation (LPO) was also determined in the hepatopancreas. The 96-h LC50 value was 1.12 μg/L. Hemolymph ChE activity showed a significant decrease in exposed prawns to FS compared to the control group, while no significant differences in the muscle were observed between groups (p < 0.05). FS caused a significant increase in the activity of antioxidant enzymes SOD, CAT, and GST compared to the control group (p < 0.02). By contrast, LPO levels were not affected by the pesticide (p < 0.05). These results indicate that P. argentinus is very sensitive to organophosphorus which alter biochemical parameters that are related to antioxidant status. Thus, these parameters could be used as biomarkers for assessing water pollution.

Histopathological effects of endosulfan to hepatopancreas, gills and ovary of the freshwater crab Zilchiopsis collastinensis (Decapoda: Trichodactylidae)

In this work, the effects of a pulse exposure of endosulfan on hepatopancreas, gills and ovary of the burrowing crab Zilchiopsis collastinensis were evaluated. The crabs were exposed to three sublethal concentrations in a pulse system with controlled dilutions. Water samples for pesticide concentrations measurements and crab tissue samples were taken when applications were made and 2, 8, 15 and 22 days after administering the pesticide. The exposure to endosulfan caused an increase in B cell number and a decrease in F and R cell number (p<0.05). Necrotic tubules, abnormal lumen and other histopathologies were observed in the hepatopancreas of crabs exposed to endosulfan. There was an increase in the proportion of collapsed gills caused by endosulfan effects. Other effects as hyperplasia were also observed. There were no changes in the gonadosomatic index of exposed crabs; however there were changes in the volume of oocytes of exposed crabs in certain days (p<0.05). The increase in B cell number and the consequent reduction in F cell number may be related to the detoxification processes. The changes in cell number within the hepatopancreas and the histopathologies observed both in hepatopancreas and gills might be used as endosulfan exposure indicators.

Histopathological and biochemical evidence of hepatopancreatic toxicity caused by cadmium in white shrimp, Palaemonetes argentinus

Cadmium (Cd) is one of the most common pollutants in the environment and induces a range of tissue changes or damages and organ dysfunction. The histopathological effects of Cd and lipid peroxidation (LPO) on hepatopancreas of the freshwater shrimp, Palaemonetes argentinus, were studied. Shrimp were obtained from two lagoons with contrasting environmental quality, De los Padres (LP, impacted site) and Nahuel Rucá (NR, reference site), and were exposed to 3.06 and 12.24µgCdL(-1) for 3, 7, 10 and 15 days. The health status of both populations was also evaluated by histological analysis of control individuals. After exposure, shrimp were transferred to clean water for 28 days to evaluate the recuperation capacity of hepatopancreas. Control shrimp from NR exhibited a normal hepatopancreas structure; unlike control shrimp from LP which showed several alterations. These results were attributed to the different environmental quality of lagoons. The exposure to Cd resulted in several alterations in the histological structure of the hepatopancreas of both populations. The observed alterations included haemocytic and connective infiltrations in the intertubular space, erosioned microvilli, ripple of basal lamina, atrophied epithelium and necrosis, however, the latter was only observed in shrimp from LP. The exposure also caused an increase of LPO levels in both populations. P. argentinus was able to repair the hepatopancreas structure from the damage caused by Cd, evidenced by the histopathological results and LPO levels. Obtained results are indicating that the histological analysis of the hepatopancreas proved to be a highly sensitive method for evaluating water quality, in both environmental and laboratory conditions.

The responsive expression of a chitinase gene in the ridgetail white prawn Exopalaemon carinicauda against Vibrio anguillarum and WSSV challenge

Chitinases are essential enzymes for crustaceans and participates in several biological processes, such as nutrient digestion, morphogenesis, pathogenesis, and pathogen defense. In the present study, the full-length cDNA of Chi (named EcChi) was cloned from the hemocytes of ridgetail white prawn Exopalaemon carinicauda by rapid amplification of cDNA ends methods. The full-length cDNA of EcChi was 1,319 bp, including contains a 5'-untranslated region (UTR) of 42 bp, 3'-UTR of 101 bp with a poly (A) tail, an open-reading frame of 1,176 bp, encoding a 391-amino acid polypeptide with the predicted molecular weight of 43.71 kDa and estimated isoelectric point of 4.78. Sequence analysis revealed that the conserved chitinases family 18 active site was predicted in the amino acid sequence of EcChi. BLAST analysis revealed that amino acids of EcChi shared high identity (61-77 %) with that of other crustaceans. Quantitative real-time PCR analysis indicated that EcChi could be detected in all the tested tissues, and strongly expressed in hepatopancreas of E. carinicauda. After challenged with Vibrio anguillarum and WSSV, EcChi transcripts both in hemocytes and hepatopancreas increased significantly in the first 3 h, respectively. These results indicated that EcChi might be involved in the innate immune responses to V. anguillarum and WSSV in E. carinicauda.

A redox active site containing murrel cytosolic thioredoxin: analysis of immunological properties

In this study, we have reported the immunological properties of cDNA encoding thioredoxin which is obtained from the database of Channa striatus (named as CsTRx) cDNA library. The analysis showed that the CsTRx polypeptide contains a thioredoxin domain between Val(2) and Asn(106). The domain possessed a thioredoxin active family at 24–42 along with a redox active site (also known as catalytic center) at (31)WCGPC(35). The analysis showed that the catalytic center is responsible for the control of protein function. Phylogenetic study showed that CsTRx clustered together with vertebrate TRx-1. Based on the phylogenetic analysis and other bioinformatics analysis, it is confirmed that the characterized CsTRx belongs to TRx-1 family. In addition, the sub-cellular localization prediction analysis showed that CsTRx is a cytosol thioredoxin. The highest gene expression was observed in gill (P < 0.05). Further, its transcriptional modulation was evaluated under fungal (Aphanomyces invadans), bacterial (Aeromonas hydrophila) and H2O2 challenges. The recombinant CsTRx protein was over-expressed and purified using an Escherichia coli expression vector system. We conducted a H2O2 peroxidase assay using recombinant CsTRx protein under various pH and temperature. Further, we studied the influence of recombinant CsTRx protein on C. striatus spleen leukocyte activation. The recombinant CsTRx protein enhanced the cell proliferation in a concentration dependant manner. The results of antioxidant analysis showed that the antioxidant capacity of recombinant CsTRx protein was determined to be 4.2 U/mg protein. We conducted an insulin disulfides assay to study the enzymatic oxidoreductase activity of CsTRx and we observed no activity in the control group. But the recombinant CsTRx protein addition rapidly increased the enzymatic oxidoreductase activity. Over all, the results showed that the CsTRx may contain potential antioxidant properties, which could regulate the oxidative stress created by various biological pathogens as well as chemical stress in the immune system of C. striatus, thus protecting it.

Molecular responses of calreticulin gene to Vibrio anguillarum and WSSV challenge in the ridgetail white prawn Exopalaemon carinicauda

Calreticulin (CRT), as a highly conserved endoplasmic reticulum luminal resident protein, plays important roles in Ca(2+) homeostasis, molecular chaperoning and response to viral infection. In this study, a full-length cDNA of CRT (designated EcCRT) was cloned from hemocytes of the ridgetail white prawn Exopalaemon carinicauda by using rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of EcCRT was 1725 bp, which contains a 5'-untranslated region (UTR) of 57 bp, 3'-UTR of 453 bp with a poly (A) tail, an open reading frame (ORF) of 1215 bp, encoding a 404 amino-acid polypeptide with the predicted molecular weight of 46.51 kDa and estimated isoelectric point of 4.32. The deduced amino acid sequence of EcCRT shared high identity (82%-85%) with that of other crustaceans. Phylogenetic analysis showed that EcCRT of E. carinicauda was clustered together with CRT of other shrimps, indicating that EcCRT should be a member of the CRT family. Quantitative real-time RT-qPCR analysis indicated that EcCRT was expressed in hemocytes, gill, hepatopancreas, muscle, ovary, intestine, stomach and eyestalk, with the highest expression level in hemocytes. After Vibrio anguillarum and WSSV challenge, the expression level of EcCRT transcripts both in the hemocytes and hepatopancreas of E. carinicauda were up-regulated in the first 6 h, respectively. The results suggested that EcCRT might be associated with the immune defenses to V. anguillarum and WSSV in E. carinicauda.

Antioxidant, lipid lowering, and membrane stabilization effect of sesamol against doxorubicin-induced cardiomyopathy in experimental rats

The present study was designed to evaluate the cardioprotective effect of sesamol against doxorubicin-induced cardiomyopathy in rats. In this study, the cardioprotective effect of sesamol against doxorubicin induced cardiomyopathy in experimental rats was evaluated at the dosage of 50 mg/kg bw. Doxorubicin was administered to rats at a total cumulative dose of 15 mg/kg through intraperitoneal route for 2 weeks in six-divided dose on 8th, 10th, 14th, 16th, 18th, and 21st day. After the last dose administration, the endogenous antioxidants and lipid peroxidation were estimated in heart tissue homogenate. Cardiac biomarkers such as troponin T, LDH, CK, and AST and lipid profiles such as cholesterol, triglycerides, HDL, LDL, and VLDL were estimated in serum. Sesamol has cardioprotective activity through normalization of doxorubicin-induced-altered biochemical parameters. Biochemical study was further supported by histopathological study, which shows that sesamol offered myocardial protection from necrotic damage. From these findings, it has been concluded that the sesamol has significant cardioprotection against doxorubicin induced cardiomyopathy via amelioration of oxidative stress, lipid lowering, and membrane stabilization effect.

Study of biochemical biomarkers in freshwater prawn Macrobrachium borellii (Crustacea: Palaemonidae) exposed to organophosphate fenitrothion

Several agrochemicals like organophosphates are extensively used to control pests in agricultural practices but they also adversely affect non-target fauna. The effect of organophosphorous fenitrothion on the prawn Macrobrachium borellii was evaluated. The 96-h LC50 was determined. Activity of superoxide dismutase, catalase, glutathione-S-transferase and lipid oxidation levels, were evaluated in the hepatopancreas from adults exposed to sublethal fenitrothion concentrations for 1, 2, 4 and 7 days. In addition, superoxide dismutase mRNA expression, acetylcholinesterase inhibition and haemocyte DNA damage were determined. The 96-h LC50 was 4.24μg/l of fenitrothion. Prawn exposed to sublethal FS concentrations showed an increase of both catalase and superoxide dismutase activities, mainly after 2 and 4 days exposure and an increase of glutathione-S-transferase activity from day 2 to day 7 while lipid oxidation levels increased mainly on day 1. Superoxide dismutase transcripts were significantly higher in fenitrothion -treated prawns, indicating an induction mechanism. Hemolymph analysis showed that while acetylcholinesterase activity decreased after 2 days, haemocytes displayed most DNA damage after 7-day exposure to fenitrothion. These results indicate that prawn enzymes are highly sensitive to fenitrothion exposure, and these biological responses in M. borellii could be valuable biomarkers to monitor organophosphorous contamination in estuarine environments.

Transcriptional regulation of extracellular copper zinc superoxide dismutase from white shrimp Litopenaeus vannamei following Vibrio alginolyticus and WSSV infection

The cDNA encoding an extracellular copper zinc superoxide dismutase (LvECSOD) was cloned from the hepatopancreas of white shrimp Litopenaeus vannamei. It consisted of 915 bp nucleotides with an open reading frame corresponding to a deduced protein of 178 amino acids. The LvECSOD contains a putative signal peptide of 16 amino acids, two potential N-linked glycosylation sites (N(115)GTA and N(135)ITG) and a copper zinc superoxide dismutase family signature sequence (G(162)NAGaRvACctI(173)). It was found that four copper binding sites, four zinc binding sites and two cysteines involving in the formation of the disulfide bridge were conserved in the protein. LvECSOD shared 33-58% identity to ECSODs from other organisms. Expression analysis revealed that LvECSOD mRNA was widely distributed in all the tissues examined. When the shrimp challenged with Vibrio alginolyticus or white spot syndrome virus (WSSV), expression of LvECSOD mRNA in the hepatopancreas and hemocytes was mediated responsively. Our results suggested that LvECSOD was implicated in the immune response induced by V. alginolyticus and WSSV.

A thioredoxin response to the WSSV challenge on the Chinese white shrimp, Fenneropenaeus chinensis

Thioredoxin (TRX) is involved in cell redox homeostasis. In addition, it is responsible for maintaining proteins in their reduced state. In our study, a Fenneropenaeus chinensis thioredoxin (FcTRX) gene was identified from the Chinese white shrimp. The full length of FcTRX was 777 bp, including a 60 bp 5' untranslated region (UTR), a 318 bp open reading frame (ORF) encoding a 105 amino acids protein, and a 399 bp 3' UTR. FcTRX contained a TRX domain with a conserved motif of Cys-Gly-Pro-Cys (CGPC). No signal peptide was predicted by SMART analysis. The molecular mass and pI of FcTRX were 12 kDa and 4.62, respectively. FcTRX is a widely distributed gene, and its mRNA is detected in hemocytes, hearts, hepatopancreas, gills, stomach, and intestine from an unchallenged shrimp. The expression level of FcTRX was the highest in hepatopancreas, where it was down-regulated to the lowest level at 12 h white spot syndrome virus (WSSV) challenge. In the gills, it went up to the highest level at 6 h. Western blot showed that FcTRX protein in hepatopancreas challenged with WSSV was down-regulated from 2 h to 12 h and then restored to the level similar to that of unchallenged shrimp at 24 h. In the gills challenged with WSSV, the FcTRX protein was up-regulated from 6 h to 24 h. Our research indicated its possible role in the anti-WSSV innate immunity of shrimps.

Molecular cloning and characterization of peroxiredoxin 6 from Chinese mitten crab Eriocheir sinensis

Peroxiredoxin is a superfamily of antioxidative proteins that play important roles in protecting organisms against the toxicity of reactive oxygen species (ROS). In this study, the full-length cDNA encoding peroxiredoxin 6 (designated EsPrx6) was cloned from Chinese mitten crab Eriocheir sinensis by using rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of EsPrx6 was of 1076 bp, containing a 5' untranslated region (UTR) of 69 bp, a 3' UTR of 347 bp with a poly (A) tail, and an open reading frame (ORF) of 660 bp encoding a polypeptide of 219 amino acids with the predicted molecular weight of 24 kDa. The conserved Prx domain, AhpC domain and the signature of peroxidase catalytic center identified in EsPrx6 strongly suggested that EsPrx6 belonged to the 1-Cys Prx subgroup. Quantitative real-time RT-PCR was employed to assess the mRNA expression of EsPrx6 in various tissues and its temporal expression in haemocytes of crabs challenged with Listonella anguillarum. The mRNA transcript of EsPrx6 could be detected in all the examined tissues with highest expression level in hepatopancreas. The expression level of EsPrx6 in haemocytes was down-regulated after bacterial challenge and significantly decreased compared to the control group at 12h. As time progressed, the expression level began to increase but did not recover to the original level during the experiment. The results suggested the involvement of EsPrx6 in responses against bacterial infection and further highlighted its functional importance in the immune system of E. sinensis.

A thioredoxin with antioxidant activity identified from Eriocheir sinensis

Thioredoxin, with a redox-active disulfide/dithiol in the active site, is the major ubiquitous disulfide reductase responsible for maintaining proteins in their reduced state. In the present study, the cDNA encoding thioredoxin-1 (designated EsTrx1) was cloned from Chinese mitten crab Eriocheir sinensis by using rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of EsTrx1 was of 641 bp, containing a 5' untranslated region (UTR) of 17 bp, a 3' UTR of 306 bp with a poly (A) tail, and an open reading frame (ORF) of 318 bp encoding a polypeptide of 105 amino acids. The high similarity of EsTrx1 with Trx1s from other animals indicated that EsTrx1 should be a new member of the Trx1 sub-family. Quantitative real-time PCR analysis revealed the presence of EsTrx1 transcripts in gill, gonad, hepatopancreas, muscle, heart and haemocytes. The expression of EsTrx1 mRNA in haemocytes was up-regulated after Listonella anguillarum challenge, reached the maximum level at 6h post-stimulation, and then dropped back to the original level gradually. In order to elucidate its biological functions, EsTrx1 was recombined and expressed in E. coli BL21 (DE3). The rEsTrx1 was demonstrated to possess the expected redox activity in enzymatic analysis, and to be more potent than GSH in antioxidant capacity. These results together indicated that EsTrx1 could function as an important antioxidant in a physiological context, and perhaps is involved in the responses to bacterial challenge.