Transcriptome analysis of Penaeus vannamei hepatopancreas reveals differences in toxicity mechanisms between phoxim and prometryne

Exposure to nanopolystyrene and phoxim at ambient concentrations causes oxidative stress and inflammation in the intestines of the Chinese mitten crab (Eriocheir sinensis)

Nanopolystyrene (NP) and phoxim (PHO) are common environmental pollutants in aquatic systems. We evaluated the toxic effects of exposure to ambient concentrations of NP and/or PHO in the intestines of the Chinese mitten crab (Eriocheir sinensis). Our study showed that histopathological changes were observed in the intestines. Specifically, NP and/or PHO exposure increased intraepithelial lymphocytes. Furthermore, NP and/or PHO exposure induced oxidative stress, as evidenced by a significant decrease in superoxide dismutase activity (SOD), peroxidase activity (POD), and total antioxidant capacity (T-AOC). Pro-inflammatory gene expression and transcriptome analysis demonstrated that NP and/or PHO exposure induced the intestinal inflammatory response. Transcriptome results showed that NP and/or PHO exposure upregulated the NF-κB signaling pathway, which is considered a key pathway in the inflammatory response. Additionally, the expression of pro-inflammatory genes significantly increased after a single exposure to NP or PHO, but it exhibited a significant decrease after the co-exposure. The downregulation of these genes in the co-exposure group likely suggested that the co-exposure mitigated intestinal inflammation response in E. sinensis. Collectively, our findings mainly showed that NP and/or PHO exposure at ambient concentrations induces oxidative stress and inflammatory response in the intestines of E. sinensis.

Differential Toxicity Responses between Hepatopancreas and Gills in Litopenaeus vannamei under Chronic Ammonia-N Exposure

Ammonia nitrogen is one of the main toxic substances in aquatic cultivation environments. Chronic exposure to excessive amounts of ammonia-N creates toxic consequences, retarding the growth of aquatic organisms. This study investigated the growth performance, morphological and physiological alterations, and transcriptome changes in the hepatopancreas and gills of white shrimp Litopenaeus vannamei. The results showed that there was no significant difference in the survival rate (p > 0.05), whereas growth performance was reduced significantly in the treated groups compared to the control groups (p < 0.05). Significant structural damage and vacuolation occurred in hepatopancreas and gill tissues in the treated groups. Superoxide dismutase (SOD) activity and Na+/K+-ATPase content were significantly increased by chronic ammonia-N exposure in the two tissue groups. In addition, catalase (CAT) activity and malondialdehyde (MDA) levels were significantly altered in the hepatopancreas groups (p < 0.05), whereas no differences were observed in the gill groups (p > 0.05). There were 890 and 1572 differentially expressed genes identified in the hepatopancreas (treated versus control groups) and gills (treated versus control groups), respectively, of L. vannamei under chronic ammonia-N exposure. Functional enrichment analysis revealed associations with oxidative stress, protein synthesis, lipid metabolism, and different serine proteases. The gills maintained cellular homeostasis mainly through high expression of cytoskeleton and transcription genes, whereas the hepatopancreas down-regulated related genes in the ribosome, proteasome, and spliceosome pathways. These genes and pathways are important in the biosynthesis and transformation of living organisms. In addition, both tissues maintained organismal growth primarily through lipid metabolism, which may serve as an effective strategy for ammonia-N resistance in L. vannamei. These results provided a new perspective in understanding the mechanisms of ammonia-N resistance in crustaceans.

Transcriptomic analysis of the antioxidant responses and immunomodulatory effects of dietary melatonin in red swamp crayfish (Procambarus clarkii)

This study aimed to investigate the effects of dietary melatonin (MT) levels on the antioxidant capacity, immunomodulatory, and transcriptional regulation of red swamp crayfish. Six experimental diets with different levels of MT (0, 22.5, 41.2, 82.7, 165.1, and 329.2 mg/kg diet) were fed to juvenile crayfish for 60 d. The transcriptome data of the control group and the group supplemented with dietary MT at 165.1 mg/kg were obtained using RNA-seq. In total, 3653 differentially expressed genes (2082 up-regulated and 1571 down-regulated) were identified. Pathways and genes related to antioxidant immune and growth performance were verified by qRT-PCR. The total hemocyte count, phagocytosis rate, and respiratory burst were significantly increased in the MT (165.1 mg/kg) group compared to the control group. Analysis of antioxidant immune-related enzymes in the hepatopancreas demonstrated that dietary MT (165.1 mg/kg) significantly increased activities of catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase and significantly decreased aspartate aminotransferase and alanine aminotransferase activity. At the transcriptional level, dietary MT up-regulated expression levels of genes associated with antioxidant immune and development, which included toll-like receptors, Crustin, C-type lectin, and so on. To conclude, MT could be used as a supplement in crayfish feed to increase immunity and antioxidant capacity and according to the broken line regression, the ideal MT concentration was the 159.02 mg/kg. Overall, this study demonstrates the role of melatonin in the antioxidant responses and immunomodulatory of Procambarus clarkii, laying the foundation for the development of melatonin as a feed additive in the aquaculture of this species.

New insights into the regulation mechanism of Pacific white shrimp (Litopenaeus vannamei) hepatopancreas under 4-nonylphenol exposure using transcriptome analysis

4-Nonylphenol (4-NP) is one of the common endocrine-disrupting chemicals (EDCs) in estuaries and coastal zones, which can exert detrimental effects on the physiological function of aquatic organisms. However, the molecular response triggered by 4-NP remains largely unknown in Pacific white shrimp (Litopenaeus vannamei). In this study, transcriptomic analysis was performed to investigate the underlying mechanisms of 4-NP toxicity in the hepatopancreas of L. vannamei. Nine RNA-Seq libraries were generated from L. vannamei at 0 h, 24 h, and 48 h following exposure to 4-NP. Compared with 0 h vs 24 h, 962 up- and 463 down-regulated differentially expressed genes (DEGs) were identified, indicating that many genes in L. vannamei were induced to resist adverse circumstances by 4-NP exposure. In contrast, 902 up- and 1027 down-regulated DEGs were revealed in the comparison of 0 h vs 48 h, demonstrating that prolonged exposure to the stress from 4-NP resulted in more inhibited genes. To validate the accuracy of the transcriptome data, eight DEGs were selected for quantitative real-time polymerase chain reaction (qRT-PCR), which were consistent with the RNA-Seq results. Through KEGG pathway enrichment analysis, three specific pathways related to hormonal effects and endocrine function of L. vannamei were enriched significantly, including tyrosine metabolism, insect hormone biosynthesis, and melanogenesis. After 4-NP stress, genes involved in tyrosine metabolism (Tyr) and melanogenesis pathway (AC, CBP, Wnt, Frizzled, Tcf, and Ras) were induced to promote melanin pigment to help shrimp resist adverse environments. In the insect hormone biosynthesis, ALDH, CYP15A1, CYP15A1/C1, and JHE genes were activated to synthesize juvenile hormone (JH), while Spook, Phm, Sad, and CYP18A1 were induced to generate molting hormone. There is an enhanced interaction between the molting hormone and JH, with JH playing a dominant role and maintaining its "classic status quo action". Our study demonstrated that 4-NP exposure led to impairments of biological functions in L. vannamei hepatopancreas. The genes and pathways identified provide novel insights into the molecular mechanisms underlying 4-NP toxicity effects in prawns and enrich the information on the toxicity mechanism of crustaceans in response to EDCs exposure.

Effects of Prometryn Exposure on Hepatopancreas Oxidative Stress and Intestinal Flora in Eriocheir sinensis (Crustacea: Decapoda)

There is growing evidence that long-term exposure to prometryn (a widely used herbicide) can induce toxicity in bony fish and shrimp. Our previous study demonstrated its 96 h acute toxicity on the crab Eriocheir sinensis. However, studies on whether longer exposure to prometryn with a lower dose induces toxicity in E. sinensis are scarce. Therefore, we conducted a 20 d exposure experiment to investigate its effects on the hepatopancreas and intestine of E. sinensi. Prometryn reduce the activities of antioxidant enzymes, increase the level of lipid peroxidation and cause oxidative stress. Moreover, long-term exposure resulted in immune and detoxification fatigue, while short-term exposure to prometryn could upregulate the expression of genes related to immunity, inflammation and detoxification. Prometryn altered the morphological structure of the hepatopancreas (swollen lumen) and intestine (shorter intestinal villi, thinner muscle layer and thicker peritrophic membrane). In addition, prometryn changed the species composition of the intestinal flora. In particular, Bacteroidota and Proteobacteria showed a dose-dependent decrease accompanied by a dose-dependent increase in Firmicutes at the phylum level. At the genus level, all exposure groups significantly increased the abundance of Zoogloea and a Firmicutes bacterium ZOR0006, but decreased Shewanella abundance. Interestingly, Pearson correlation analysis indicated a potential association between differential flora and hepatopancreatic disorder. Phenotypic abundance analysis indicated that changes in the gut flora decreased the intestinal organ's resistance to stress and increased the potential for opportunistic infection. In summary, our research provides new insights into the prevention and defense strategies in response to external adverse environments and contributes to the sustainable development of E. sinensis culture.

Effects of prometryn on oxidative stress, immune response and apoptosis in the hepatopancreas of Eriocheir sinensis (Crustacea: Decapoda)

Prometryn, a triazine pesticide product used to control weed growth, poses a high risk to aquatic organisms in the environment. Several toxicological evaluations have been performed on bony fish and shrimp exposed to prometryn. However, there have been no reports conducted on the toxic mechanism of prometryn with regard to Eriocheir sinensis. In this study, our research evaluated the toxic effects of prometryn via in vitro and in vivo toxicity tests on E. sinensis. Firstly, we estimated the exposure toxicity of prometryn to E. sinensis, and then we constructed a 6 h transcriptional profile and conducted an enrichment analysis. To further reveal the toxicity of prometryn, the hepatopancreas (hepatopancreatic cells) was analyzed for antioxidant, immune and lipid-metabolism-related enzymes, antioxidant- and apoptosis-related gene expression, histopathology and TUNEL. From the results, we determined that the 96 h-LD50 was 70.059 mg/kg, and using RNA-seq, we identified 933 differentially expressed genes (DEGs), which were mainly enriched in the amino and fatty acid metabolism and the cell-fate-determination-related signaling pathway. The results of the biochemical assays showed that prometryn could significantly decrease the activities/levels of CAT, SOD, GSH, AKP and ACP, reduce the levels of T-AOC, TG, TCH, C3 and C4, and increase the MDA content. In addition, the expression levels of Nrf2, GSTs and HO-1 were first upregulated and then downregulated with increasing time. Histopathology showed that prometryn damaged the structure of the hepatopancreas cells and induced apoptosis, suggesting that the PI3K-Akt signaling pathway may be involved in the damage process of hepatopancreas cells (PI3K, PDK and Akt were downregulated whereas Bax was upregulated), leading to their apoptosis. The above results indicated that prometryn could cause injury of the hepatopancreas through oxidative stress, induce cell apoptosis, disrupt the lipid metabolism and cause immune damage. This study provided useful data for understanding and evaluating the toxicity of prometryn to aquatic crustacea.

Combined transcriptome and metabolome analysis reveal key regulatory genes and pathways of feed conversion efficiency of oriental river prawn Macrobrachium nipponense

BACKGROUND

Oriental river prawn Macrobrachium nipponense is an economically important aquaculture species in China, Japan, and Vietnam. In commercial prawn farming, feed cost constitutes about 50 to 65% of the actual variable cost. Improving feed conversion efficiency in prawn culture will not only increase economic benefit, but also save food and protect the environment. The common indicators used for feed conversion efficiency include feed conversion ratio (FCR), feed efficiency ratio (FER), and residual feed intake (RFI). Among these, RFI is much more suitable than FCR and FER during the genetic improvement of feed conversion efficiency for aquaculture species.

RESULTS

In this study, the transcriptome and metabolome of hepatopancreas and muscle of M. nipponense from high RFI low RFI groups, which identified after culture for 75 days, were characterized using combined transcriptomic and metabolomic analysis. A total of 4540 differentially expressed genes (DEGs) in hepatopancreas, and 3894 DEGs in muscle were identified, respectively. The DEGs in hepatopancreas were mainly enriched in KEGG pathways including the metabolism of xenobiotics by cytochrome P450 (down-regulated), fat digestion and absorption (down-regulated) and aminoacyl-tRNA biosynthesis (up-regulated), etc. The DEGs in muscle were mainly enriched in KEGG pathways including the protein digestion and absorption (down-regulated), glycolysis/gluconeogenesis (down-regulated), and glutathione metabolism (up-regulated), etc. At the transcriptome level, the RFI of M. nipponense was mainly controlled in biological pathways such as the high immune expression and the reduction of nutrients absorption capacity. A total of 445 and 247 differently expressed metabolites (DEMs) were identified in the hepatopancreas and muscle, respectively. At the metabolome level, the RFI of M. nipponense was affected considerably by amino acid and lipid metabolism.

CONCLUSIONS

M. nipponense from higher and lower RFI groups have various physiological and metabolic capability processes. The down-regulated genes, such as carboxypeptidase A1, 6-phosphofructokinase, long-chain-acyl-CoA dehydrogenase, et. al., in digestion and absorption of nutrients, and the up-regulated metabolites, such as aspirin, lysine, et. al., in response to immunity could be potential candidate factors contributed to RFI variation for M. nipponense. Overall, these results would provide new insights into the molecular mechanism of feed conversion efficiency and assist in selective breeding to improve feed conversion efficiency in M. nipponense.

Identification of key immune and stress related genes and pathways by comparative analysis of the gene expression profile under multiple environmental stressors in pacific white shrimp (Litopenaeus vannamei)

Water salinity, pH, and nitrite concentration are considered environmental factors affecting the growth rate, survival, health, and physiological conditions of aquatic animals. The identification of key genes that are involved in the response to environmental stressors is essential for controlling stress in aquatic animals and sustainable aquaculture. In this study, RNA sequencing was performed to identify the differentially expressed genes (DEGs) and biological pathways that are involved in the response of the hepatopancreas to environmental stressors, including low salinity stress, nitrite stress, low pH stress, and high pH stress. The DEGs were enriched in biological pathways related to immune response, energy metabolism, oxidative stress response, hemostasis, and enzymatic activity of the hepatopancreas. In addition to the identification of DEGs related to each stressor, some DEGs were found to be expressed among all groups. The most important overlapping DEGs under multiple stressors were juvenile hormone esterase-like protein 2 (JHE-like), myosin light chain, C-type lectin 2, myosin-9-like, anti-lipopolysaccharide factor 1 (ALF-1), peroxisomal acyl-coenzyme An oxidase 1-like (ACX1), hepatic lectin-like, venom phosphodiesterase 2-like, hemolymph clottable protein-like (CP), cathepsin L, and Ras-like protein 2. The results of the present study provide additional information regarding the transcriptional response of the hepatopancreas to low salinity, nitrite, low pH, and high pH stress. Moreover, the discovery of several overlapping DEGs among different stressors provided a better understanding of the molecular function of the hepatopancreas.

Chlorphoxim induces neurotoxicity in zebrafish embryo through activation of oxidative stress

It is known that chlorphoxim is a broad-spectrum and high-effective pesticide. With the wide use in agricultural practice, chlorphoxim residue is also frequently detected in water, but its potential toxicity to aquatic life is still unclear. In this study, zebrafish is used as a model to detect the toxicity of chlorphoxim. Our results showed that exposure of high concentration of chlorphoxim at 96 h post-fertilization (hpf) resulted in a high mortality and pericardium edema rate, a low hatchability rate and heart rate. The nervous system damage, swimming behavior alteration and acetylcholinesterase (AChE) inhibition were measured in zebrafish embryos after a 6 days post-fertilization (dpf) of chlorphoxim exposure. The expression of neural-related genes is abnormal in zebrafish embryos. Chlorphoxim exposure significantly increases oxidative stress in zebrafish embryos by inhibiting antioxidant enzyme (SOD and CAT) and activating reactive oxygen species (ROS). As expected, chlorphoxim exposure induces apoptosis by enhancing the expression of apoptotic genes (Bax, Bcl2, and p53). Astaxanthin (ATX), an effective antioxidant, was found to be able to rescue the neurotoxicity of chlorphoxim through relieving oxidative stress and apoptosis. Altogether, the results showed that chlorphoxim exposure led to severe neurotoxicity to zebrafish embryos, which was contributed to a more comprehensive understanding of the safety use of the organophosphorus pesticide.

Effects of dietary Ginkgo biloba leaf extract on growth performance, immunity and environmental stress tolerance of Penaeus vannamei

Ginkgo biloba leaf extract (GBE) has been extensively used in the treatment of diseases due to its anti-inflammatory, antioxidant, and immunomodulatory effects. In aquaculture, GBE is widely used as a feed additive, which is important to enhance the immunity of aquatic animals. The current study evaluated the effects of adding GBE to the diet of Penaeus vannamei (P. vannamei) under intensive aquaculture. The GBE0 (control group), GBE1, GBE2, and GBE4 groups were fed a commercial feed supplemented with 0.0, 1.0, 2.0, and 4.0 g/kg GBE for 21 days, respectively. The results showed that dietary GBE could alleviate hepatopancreas tissue damage and improve the survival rate of shrimp, and dietary 2 g/kg GBE could significantly increase the total hemocyte count (THC), the hemocyanin content, the antioxidant gene's expression, and the activity of their encoded enzymes in P. vannamei. Furthermore, transcriptome data revealed that immunity-related genes were upregulated in the GBE2 group compared with the GBE0 group after 21 days of culture. Drug metabolism-cytochrome P450, sphingolipid metabolism, linoleic acid metabolism, glycerolipid metabolism, fat digestion and protein digestion and absorption pathways were significantly enriched, according to KEGG results. Surprisingly, all of the above KEGG-enriched pathways were significantly upregulated. These findings demonstrated that supplementing P. vannamei with 2 g/kg GBE improved its environmental adaptability by improving immunity, lipid metabolism, and detoxification. In this study, a comprehensive evaluation of the effects of dietary GBE on the intensive aquaculture of P. vannamei was conducted to provide a reference for the healthy culture of P. vannamei.

Joint toxic effects of phoxim and lambda-cyhalothrin on the small yellow croaker (Larimichthys polyactis)

Although pesticides commonly exist as combinations in real-life situations of the aquatic ecosystem, the impact of the toxicity of their mixtures has remained largely unclear. In this study, we investigated the combined effects of two neurotoxic pesticides, including one organophosphate insecticide phoxim (PHO) and one pyrethroid insecticide lambda-cyhalothrin (LCY), on the embryos of the small yellow croaker (Larimichthys polyactis), and their potential pathways. LCY exhibited higher toxicity relative to PHO, with a 72-h LC₅₀ value of 0.0074 mg a.i. L^-1, while the corresponding value for PHO was 0.12 mg a.i. L^-1. The mixture of PHO and LCY exerted a synergistic effect on the embryos of L. polyactis. The activities of antioxidant enzyme CAT and apoptotic enzyme caspase 3 were substantially changed in most single and combined exposure groups relative to the baseline value. Under both single and combined exposures, more significant changes were found in the mRNA expression of five genes, including the immunosuppression gene ngln2, the apoptosis gene P53, the endocrine system gene cyp19a1b, as well as neurodevelopment genes of ap and acp2, relative to the baseline value. Furthermore, the non-target metabolomic analysis demonstrated that hundreds of differential metabolites, including two bile acids (taurodeoxycholic acid and tauroursodeoxycholic acid), were significantly increased in the exposure groups. The bile acids were closely associated with the gut microbiota, and 16S rRNA sequencing results demonstrated dysfunction of the gut microbiota after exposure, especially in the combined exposure group. Our findings indicated that there might be a potential risk connected to the co-occurrence of these two pesticides in aquatic vertebrates. Consequently, future ecological risk assessments should incorporate synergistic mixtures because the current risk assessments do not consider them.

Comprehensive Transcriptomic and Metabolomic Analysis of the Litopenaeus vannamei Hepatopancreas After WSSV Challenge

Litopenaeus vannamei is the major farmed shrimp species worldwide. White spot disease due to white spot syndrome virus (WSSV) is severely affecting shrimp worldwide, causing extensive economic losses in L. vannamei culture. This is the first study that applied combined transcriptomic and metabolomic analysis to study the effects on the L. vannamei hepatopancreas after WSSV challenge. Our transcriptomic data revealed differentially expressed genes (DEGs) associated with immunity, apoptosis, the cytoskeleton and the antioxidant system in the hepatopancreas of L. vannamei. Metabolomic results showed that WSSV disrupts metabolic processes including amino acid metabolism, lipid metabolism and nucleotide metabolism. After challenged by WSSV, immune-related DEGs and differential metabolites (DMs) were detected in the hepatopancreas of L. vannamei, indicating that WSSV may damage the immune system and cause metabolic disorder in the shrimp. In summary, these results provide new insights into the molecular mechanisms underlying L. vannamei's response to WSSV.

Effects of chronic prometryn exposure on antioxidative status, intestinal morphology, and microbiota in sea cucumber (Apostichopus japonicus)

Prometryn is an occasional triazine herbicide used in aquaculture to kill algae. However, deposition of prometryn at the bottom of the pond poses a potential threat to aquatic animals, especially benthos, such as the sea cucumber. This study investigated the toxic effects of prometryn oral exposure on antioxidants, and the intestinal histomorphology and microbiome of sea cucumbers. Results showed that the accumulation of prometryn in the intestine, respiratory tree, and body wall decreased sequentially under the same level. Severe pathological damages were observed in the intestines of sea cucumbers fed with 0.080 and 1.595 g/kg prometryn (measured concentration). Moreover, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) concentrations were significantly increased in prometryn treatment groups compared to the control group (P < 0.05), while the catalase (CAT) activity was significantly decreased (P < 0.05) in the coelomic fluid of treatment groups. At the phylum level, the abundance of Proteobacteria was significantly higher in the 0.080 g/kg treatment group than in the control group. In addition, prometryn exposure reduced the diversity of intestinal microflora in sea cucumbers. In conclusion, these results suggest that prometryn has potential toxicity to sea cucumber. Therefore, the harm of prometryn deposited in the sediment to aquatic animals must be a concern in aquaculture.

Transcriptome analysis to elucidate the toxicity mechanisms of fenvalerate, sulfide gatifloxacin, and ridomil on the hepatopancreas of Procambarus clarkii

Most antibiotics, insecticides, and other chemicals used in agricultural and fishery production tend to persist in the environment. Fenvalerate, sulfide gatifloxacin, and ridomil are widely used in aquaculture as antibacterial, antifungal, and antiparasitic drugs; however, their toxicity mechanism remains unclear. Thus, we herein analyzed the effects of these three drugs on the hepatopancreas of Procambarus clarkii at the transcriptome level. Twelve normalized cDNA libraries were constructed using RNA extracted from P. clarkii after treatment with fenvalerate, sulfide gatifloxacin, or ridomil and from an untreated control group, followed by Kyoto Encyclopedia of Genes and Genomes pathway analysis. In the control vs fenvalerate and control vs sulfide gatifloxacin groups, 14 and seven pathways were significantly enriched, respectively. Further, the effects of fenvalerate and sulfide gatifloxacin were similar on the hepatopancreas of P. clarkii. We also found that the expression level of genes encoding senescence marker protein-30 and arylsulfatase A was downregulated in the sulfide gatifloxacin group, indicating that sulfide gatifloxacin accelerated the apoptosis of hepatopancreatocytes. The expression level of major facilitator superfamily domain containing 10 was downregulated, implying that it interferes with the ability of the hepatopancreas to metabolize drugs. Interestingly, we found that Niemann pick type C1 and glucosylceramidase-β potentially interact with each other, consequently decreasing the antioxidant capacity of P. clarkii hepatopancreas. In the fenvalerate group, the downregulation of the expression level of xanthine dehydrogenase indicated that fenvalerate affected the immune system of P. clarkii; moreover, the upregulation of the expression level of pancreatitis-associated protein-2 and cathepsin C indicated that fenvalerate caused possible inflammatory pathological injury to P. clarkii hepatopancreas. In the ridomil group, no pathway was significantly enriched. In total, 21 genes showed significant differences in all three groups. To conclude, although there appears to be some overlap in the toxicity mechanisms of fenvalerate, sulfide gatifloxacin, and ridomil, further studies are warranted.

Complete Genome Sequence and Function Gene Identify of Prometryne-Degrading Strain Pseudomonas sp. DY-1

The genus Pseudomonas is widely recognized for its potential for environmental remediation and plant growth promotion. Pseudomonas sp. DY-1 was isolated from the agricultural soil contaminated five years by prometryne, it manifested an outstanding prometryne degradation efficiency and an untapped potential for plant resistance improvement. Thus, it is meaningful to comprehend the genetic background for strain DY-1. The whole genome sequence of this strain revealed a series of environment adaptive and plant beneficial genes which involved in environmental stress response, heavy metal or metalloid resistance, nitrate dissimilatory reduction, riboflavin synthesis, and iron acquisition. Detailed analyses presented the potential of strain DY-1 for degrading various organic compounds via a homogenized pathway or the protocatechuate and catechol branches of the β-ketoadipate pathway. In addition, heterologous expression, and high efficiency liquid chromatography (HPLC) confirmed that prometryne could be oxidized by a Baeyer-Villiger monooxygenase (BVMO) encoded by a gene in the chromosome of strain DY-1. The result of gene knock-out suggested that the sulfate starvation-induced (SSI) genes in this strain might also involve in the process of prometryne degradation. These results would provide the molecular basis for the application of strain DY-1 in various fields and would contribute to the study of prometryne biodegradation mechanism as well.

Protective Effect of Se-Methylselenocysteine on Elaidic Acid-Induced Inflammation in Human Arterial Endothelial Cells

This study was designed to investigate the anti-inflammatory effect of Se-methylselenocysteine (MSC) on elaidic acid (9t18:1, EA) induced human arterial endothelial cells (HAECs). MTT and flow cytometry were used to determine cell viability and cell apoptosis respectively. Western blotting was used to assess protein expression of intercellular adhesion molecular 1 (ICAM-1), E-selectin, interleukin-8 (IL-8), endothelial nitric oxide synthase (e-NOS) and phospholipases A2 (PLA2), while enzyme-linked immunosorbent assay (ELISA) was performed to examine the secretion level of nitric oxide (NO). In the cell viability assay, EA significantly decreased cell viability when compared with negative control (NC) group, and MSC effectively reversed this adverse effect, especially at the concentration of 200 μmol/L with 24 h incubation. Also, the same concentration of MSC prevented HAECs cell apoptosis induced by EA. In addition, we found that the expression of ICAM-1, E-selectin, IL-8 and PLA2 were significantly increased and e-NOS decreased in EA group compared with NC group. Inhibition of PLA2 promoted ICAM-1, E-slectin and IL-8 expression in HAECs induced by EA. And MSC down-regulated the secretion of NO level in EA-induced HAECs. Based on these results, we concluded that MSC activated PLA2 which regulated the expression of ICAM-1, E-selectin and IL-8 to protect inflammation induced by EA in HEACs.