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Detoxification Reactions (detoxification + reaction)
Selected AbstractsChronic toxicity and responses of several important enzymes in Daphnia magna on exposure to sublethal microcystin-LRENVIRONMENTAL TOXICOLOGY, Issue 3 2005Wei Chen Abstract In the current study, the toxicological mechanisms of microcystin-LR and its disadvantageous effects on Daphnia magna were examined. Survival rate, number of newborn, activity of several important enzymes [glutathione S-transferase (GST), lactate dehydrogenase (LDH), phosphatases, and glutathione], accumulated microcystins, and ultrastructural changes in different organs of Daphnia were monitored over the course of 21-day chronic tests. The results indicated that low concentrations of dissolved microcystin had no harmful effect on Daphnia. On the contrary, stimulatory effects were detected. In the presence of toxin at high dosage and for long-term exposure, GST and glutathione levels decreased significantly. The decreased enzyme activity in the antioxidant system probably was caused by detoxification reactions with toxins. And these processes of detoxification at the beginning of chronic tests may enable phosphatases in Daphnia magna to withstand inhibition by the toxins. At the same time, we also found that the LDH activity in test animals increased with exposure to microcystin-LR, indicating that adverse effects occurred in Daphnia. With microcystin given at a higher dosage or for a longer exposure, the effect on Daphnia magna was fatal. In the meantime, microcystin began to accumulate in Daphnia magna, and phosphatase activity started to be inhibited. From the ultrastructure results of cells in D. magna, we obtained new information: the alimentary canal may be the target organ affected by exposure of microcystins to D. magna. The results of the current study also suggested that the oxidative damage and PPI (protein phosphatase inhibition) mechanisms of vertebrates also are adapted to Daphnia. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 323,330, 2005. [source] Mycothiol-dependent proteins in actinomycetesFEMS MICROBIOLOGY REVIEWS, Issue 3 2007Mamta Rawat Abstract The pseudodisaccharide mycothiol is present in millimolar levels as the dominant thiol in most species of Actinomycetales. The primary role of mycothiol is to maintain the intracellular redox homeostasis. As such, it acts as an electron acceptor/donor and serves as a cofactor in detoxification reactions for alkylating agents, free radicals and xenobiotics. In addition, like glutathione, mycothiol may be involved in catabolic processes with an essential role for growth on recalcitrant chemicals such as aromatic compounds. Following a little over a decade of research since the discovery of mycothiol in 1994, we summarize the current knowledge about the role of mycothiol as an enzyme cofactor and consider possible mycothiol-dependent enzymes. [source] Transcriptional signatures in response to wheat germ agglutinin and starvation in Drosophila melanogaster larval midgutINSECT MOLECULAR BIOLOGY, Issue 1 2009H.-M. Li Abstract One function of plant lectins such as wheat germ agglutinin is to serve as defences against herbivorous insects. The midgut is one critical site affected by dietary lectins. We observed marked cellular, structural and gene expression changes in the midguts of Drosophila melanogaster third instar larvae that were fed wheat germ agglutinin. Some of these changes were similar to those observed in the midguts of starved D. melanogaster. Dietary wheat germ agglutinin caused shortening, branching, swelling, distortion and in some cases disintegration of the midgut microvilli. Starvation was accompanied primarily by shortening of the microvilli. Microarray analyses revealed that dietary wheat germ agglutinin evoked differential expression of 61 transcripts; seven of these were also differentially expressed in starved D. melanogaster. The differentially transcribed gene clusters in wheat germ agglutinin-fed larvae were associated with (1) cytoskeleton organization; (2) digestive enzymes; (3) detoxification reactions; and (4) energy metabolism. Four possible transcription factor binding motifs were associated with the differentially expressed genes. One of these exhibited substantial similarity to MyoD, a transcription factor binding motif associated with cellular structures in mammals. These results are consistent with the hypothesis that wheat germ agglutinin caused a starvation-like effect and structural changes of midgut cells of D. melanogaster third-instar larvae. [source] SHORT COMMUNICATION: Increased Expression of Glutathione by Estradiol, Tumor Necrosis Factor-Alpha, and Interleukin 1-Beta in Endometrial Stromal CellsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2009Sa Ra Lee Problem, The intracellular antioxidant system, based on glutathione (GSH), plays a key role in endometrial detoxification reactions and has been proposed to be involved in the pathogenesis endometriosis. This study was designed to evaluate whether estradiol (E2) and proinflammatory cytokines have any effects on expression of glutathione in endometrial stromal cells (ESCs). Method of study, Glutathione levels were measured utilizing high-performance liquid chromatography following in vitro culture and treatment of ESCs with estradiol, tumor necrosis factor-alpha (TNF-,) and interleukin 1-beta (IL-1,). Results, The GSH level in E2 (10,8 m) treatment group was significantly higher than in the control group at 48 h (P < 0.05). In vitro treatment of ESCs with TNF-, 10 ng/mL as well as E2 (10,8 m) plus TNF-, 10 ng/mL for 48 hr also led to a significant increase in GSH level (P < 0.05; P < 0.05, respectively). Both IL-1, 10 ng/mL and E2 (10,8 m) plus IL-1, 10 ng/mL for 48 hr increased GSH level significantly (P < 0.05; P < 0.05, respectively) as well. Conclusions, These findings might suggest that increased production of estradiol and proinflammatory cytokines in the peritoneal cavity possibly leads to the establishment of endometriosis through increased level of GSH. [source] | ||||||||||