Artesunate Effect on Schistosome Thioredoxin Glutathione Reductase and Cytochrome c Peroxidase as New Molecular Targets in Schistosoma mansoni-infected Mice

Objective To investigate the possible effect of artesunate （ART） on schistosome thioredoxin glutathione reductase （TGR） and cytochrome c peroxidase （CcP） in Schistosoma mansoni-infected mice. Methods A total of 200 laboratory bred male Swiss albino mice were divided into 4 groups （50 mice in each group）. Group I： infected untreated group （Control group） received a vehicle of 1% sodium carbonyl methylcellulose （CMC-Na）; Group II： infected then treated with artesunate; Group III infected then treated with praziquantel, and group IV： infected then treated with artesunate then praziquantel. Adult S. mansoni worms were collected by Animal Perfusion Method, tissue egg counted, TGR, and CcP mRNA Expression were estimated of in $. mansoni adult worms by semi-quantitative rt-PCR. Results Semi-quantitative rt-PCR values revealed that treatment with artesunate caused significant decrease in expression of schistosome TGR and CcP in comparison to the untreated group. In contrast, the treatment with praziquantel did not cause significant change in expression of these genes. The results showed more reduction in total worm and female worm count in combined ART-PZQ treated group than in monotherapy treated groups by either ART or PZO, Moreover, complete disappearance （100%） of tissue eggs was recorded in ART-PZQ treated group with a respective reduction rate of 95.9% and 68.4% in ART- and PZQ-treated groups. Conclusion The current study elucidated for the first time that anti-schistosomal mechanisms of artesunate is mediated via reduction in expression of schistosome TGR and CcP. Linking these findings, addition of artesunate to praziquantel could achieve complete cure outcome in treatment of schistosomiasis.

Glutathione Reductase, Liver Transaminases and Atypical Lymphocytes Count as Early Predictive Biomarkers in Diagnosis of Thrombocytopenia in Dengue Viral Infection

Objective: The aim of the study is to identify whether Atypical Lymphocyte (AL), liver transaminases, and Glutathione Reductase (GR) can be used as potential biomarkers in the assessment of severity and thrombocytopenia in dengue. Methods: A cross-sectional analytical study was carried out on diagnosed dengue patients admitted to Nawaloka Hospital, Sri Lanka. Blood samples were taken from patients (n = 50) on the day of admission, 3rd and 5th day from admission for analysis of GR, aspartate transaminase, alanine transaminase, platelets, white blood cells, and Atypical Lymphocytes (AL). Results: GR level of all three measured stages had a higher area under the curve (>88%), high sensitivity and specificity compared to liver transaminases. A significant regression model represents on admission GR and AL levels as predictive variables to platelet levels in day 03 from admission (Day 3 Platelet level = 127155.3 - 383 * GR - 0.431 * AL). Conclusion: Liver transaminases, GR, and AL% can be considered as a profile of predictive biomarkers in early diagnosis of severity of dengue infection. The degree of thrombocytopenia can be predicted using on admission GR and AL% level in acute dengue viral infection.

Decreased glutathione reductase2 leads to early leaf senescence in Arabidopsis

Glutathione reductase（GR） catalyzes the reduction of glutathione disulfide（GSSG） to reduced glutathione（GSH）and participates in the ascorbate-glutathione cycle, which scavenges H_2O_2. Here, we report that chloroplastic/mitochondrial GR2 is an important regulator of leaf senescence. Seed development of the homozygous gr2 knockout mutant was blocked at the globular stage. Therefore, to investigate the function of GR2 in leaf senescence, we generated transgenic Arabidopsis plants with decreased GR2 using RNAi. The GR2 RNAi plants displayed early onset of age-dependent and darkand H2O2-induced leaf senescence, which was accompanied by the induction of the senescence-related marker genes SAG12 and SAG13. Furthermore, transcriptome analysis revealed that genes related to leaf senescence, oxidative stress, and phytohormone pathways were upregulated directly before senescence in RNAi plants. In addition, H2O2 accumulated to higher levels in RNAi plants than in wild-type plants and the levels of H_2O_2 peaked in RNAi plants directly before the early onset of leaf senescence. RNAi plants showed a greater decrease in GSH/GSSG levels than wild-type plants during leaf development. Our results suggest that GR2 plays an important role in leaf senescence by modulating H_2O_2 and glutathione signaling in Arabidopsis.

High-throughput screening against thioredoxin glutathione reductase identifies novel inhibitors with potential therapeutic value for schistosomiasis

Background:Schistosomiasis,a parasitic disease also known as bilharzia and snail fever,is caused by different species of flatworms,such as Schistosoma mansoni(S.mansoni).Thioredoxin glutathione reductase(TGR)from S.mansoni(SmTGR)is a well-characterized drug target for schistosomiasis,yet no anti-SmTGR compounds have reached clinical trials,suggesting that therapeutic development against schistosomiasis might benefit from additional scaffolds targeting this enzyme.Methods:A high-throughput screening(HTS)assay in vitro against SmTGR was developed and applied to a diverse compound library.SmTGR activity was quantified with ThioGlo®,a reagent that fluoresces upon binding to the free sulfhydryl groups of the reaction product GSH(reduced glutathione).Results:We implemented an HTS effort against 59,360 synthetic compounds.In the primary screening,initial hits(928 or 1.56%)showing greater than 90%inhibition on SmTGR activity at a final concentration of 10μM for each compound were identified.Further tests were carried out to confirm the effects of these hits and to explore the concentration-dependent response characteristics.As a result,74 of them(0.12%)representing 17 chemical scaffolds were confirmed and showed a great concentration-dependent inhibitory trend against SmTGR,including structures previously shown to be lethal to schistosomal growth.Of these,two scaffolds displayed a limited structure-activity relationship.When tested in cultured larvae,39 compounds had cidal activity in 48 h,and five of them killed larvae completely at 3.125μM.Of these,three compounds also killed adult worms ex vivo at concentrations between 5μM and 10μM.Conclusion:These confirmed hits may serve as starting points for the development of novel therapeutics to combat schistosomiasis.

Influence of temperature on glutathione level and glutathione-related enzyme activities of Antarctic ice microalgae Chlamydomonas sp.ICE-L

GSH system plays a role in the control of the redox balance state, anti-oxidation and protecting life from injury of ROS （ reactive oxygen species）. In present paper, the possible GSH system of Chlamydomonas sp. ICE-L has been investigated by evaluating GSH and GSH-related enzymatic responses at different temperatures using spectrophotometer methods. The results showed that the GSH system is correlated positively to low temperature, and other factors but GR are correlated negatively to high temperature. So GSH and GSH-related enzymes play an important role in the adaptation of Antarctic ice microalgae to low temperature.

Effect of Cadmium Stress on the Growth, Antioxidative Enzymes and Lipid Peroxidation in Two Kenaf (Hibiscus cannabinus L.) Plant Seedlings

The effects of cadmium stress on the growth, antioxidative enzymes and lipid peroxidation in two kenaf plants, Fuhong 991 and ZM412, were analysed under control （0.5-strength Hoagland＇s nutrient solution） or five levels of cadmium stress （0.5- strength Hoagland＇s nutrient solution containing different concentrations of Cd2＋）. The leaves and roots of control and cadmium-stressed plants were harvested after 3 wk. At the same Cd concentration, the Cd tolerance index of Fuhong 991 was higher than that of ZM412, indicating that Fuhong 991 may be more tolerant to Cd than ZM412. The superoxide dismutase （SOD）, catalase activity （CAT） and peroxidase （POD） activities fluctuated in the leaves of the Cd-stressed plants compared to the control, whereas the glutathione reductase activity （GR） was much larger than the control for Fuhong 991, ensuring that sufficient quantities of GSH were available to respond to the cadmium stress. In comparison to the control, the dynamic tendency of the SOD, CAT and POD activities in roots of the Cd-stressed plants all increased and then declined, but the POD activity of Fuhong 991 remained nearly unchanged at all of the stress levels. The increase in the enzyme activities demonstrated that Fuhong 991 was more tolerant to cadmium than ZM 412. The lipid peroxidation was enhanced only in the leaves of Cd-stressed ZM 412. These findings indicated that antioxidative activities may play important roles in Cd-stressed Fuhong 991 and ZM 412 and that the leaf and root cell membranes of Fuhong 991 have a greater stability than those of ZM 412. For pollution monitoring purposes, the GR activity in the roots and leaves may serve as a biomarker of Cd for Fuhong 991, whereas lipid peroxidation may serve as biomarker for ZM 412.

Effect of Cd on GSH and GSH-related enzymes of Chlamydomonas sp.ICE-L existing in Antarctic ice

Glutathione(GSH) and GSH-related enzymes play a great role in protecting organisms from oxidative damage. The GSH level and GSH-related enzymes activities were investigated as well as the growth yield and malonyldialdehyde(MDA) content in the Antarctic ice microalga Chlamydomonas sp. ICE-L exposure to the different cadmium concentration in this paper. The results showed that the higher concentration Cd inhibited the growth of ICE-L significantly and Cd would induce formation of MDA. At the same time, it is clear that GSH level, glutathione peroxidases(GPx) activity and glutathione S\|transferases(GST), activity were higher in ICE-L exposed to Cd than the control. But GR activity dropped notably when ICE-L were cultured in the medium containing Cd. Increase of GSH level, GPx and GST activities acclimate to oxidative stress induced by Cd and protect Antarctic ice microalga Chlamydomonas sp. ICE-L from toxicity caused by Cd exposure. These parameters may be used to assess the biological impact of Cd in the Antarctic pole region environment.

High Temperature and the Ethylene Antagonist 1-Methylcyclopropene Alter Ethylene Evolution Patterns,Antioxidant Responses,and Boll Growth in Gossypium hirsutum

The cotton (Gossypium hirsutum L.) crop experiences high temperatures during flowering and boll development, but information regarding the impact of ethylene inhibition and high temperature on early boll development is limited. The objective of this study was to determine the effects of high temperature and the anti-ethylene compound 1-methylcy-cloprone (1-MCP) on G. hirsutum boll development. Treatments consisted of temperature regime (38/20?C and 30/ 20?C), 1-MCP treatment, and days past anthesis (DPA). High temperature decreased ethylene synthesis by 61% at 2 DPA, and 1-MCP caused a 40% decrease in ethylene production at 1 DPA. Glutathione reductase activity increased under high temperature, whereas superoxide dismutase activity (SOD) and membrane peroxidation (malondialdehyde content) remained unchanged. 1-MCP treatment did not affect GR activity in developing bolls. High temperature and 1-MCP treatment increased the weight of cotton bolls collected 8 DPA with an increase of 0.7 and 1 g, respectively. We propose that increased GR activity in bolls exposed to high temperature may mitigate oxidative damage. Additionally, we conclude that ethylene inhibition (either high temperature or 1-MCP-induced) immediately after flowering (1 or 2 DPA) could potentially have positive impacts on early boll growth.