Pb胁迫下外源GSH对马蔺体内Pb积累和非蛋白巯基化合物含量的影响

采用溶液培养研究Pb胁迫以及Pb胁迫下添加外源谷胱甘肽(GSH)和丁胱亚磺酰胺(BSO)对马蔺根和叶干质量、Pb含量以及非蛋白巯基总肽(NPT)、谷胱甘肽(GSH)和其他非蛋白巯基化合物(植物螯合肽(PC)、半胱氨酸(Cys))含量的影响.结果表明,300 mg/L高浓度Pb胁迫下马蔺根系内Pb的大量积累显著抑制马蔺根系的生长,但同浓度Pb胁迫下添加100 mg/L GSH后马蔺体内Pb含量和干质量均不同程度增加,尤其是地上部,地上部干质量比300 mg/L单独Pb胁迫下马蔺根系干质量增加20.5％,接近于对照水平.而300 mg/L的Pb胁迫下添加100 mg/L BSO(GSH和PC合成抑制剂)后马蔺根系和地上部干质量均不同程度下降,根系降幅较大.根和叶中非蛋白巯基化合物含量检测显示,与单独Pb胁迫相比,Pb胁迫下添加GSH后马蔺根系和地上部NPT、GSH和其他非蛋白巯基化合物含量均呈增加的趋势;而Pb胁迫下添加BSO后除马蔺地上部其他非蛋白巯基化合物含量略有增加外,马蔺根系和地上部NPT、GSH和其他非蛋白巯基化合物含量较单一Pb胁迫下均出现不同程度下降,尤其根系内GSH含量降幅最大.综合分析Pb胁迫下添加外源GSH和BSO后马蔺干质量、Pb含量以及不同非蛋白巯基化合物含量的变化及关系,表明Pb胁迫下添加BSO后马蔺生物量的下降可能与非蛋白巯基化合物合成受抑尤其是GSH的合成降低有关.因此,Pb胁迫下GSH在马蔺Pb吸收转运和解毒中具有更重要的作用.     

镉、锌胁迫对番茄幼苗生长及脯氨酸和谷胱甘肽含量的影响

研究水培条件下,重金属镉、锌胁迫对番茄种子萌发、幼苗生长及相关生理指标的影响。结果表明:镉、锌溶液(2.000 mmol/L)能明显抑制种子的发芽势、发芽率和根的伸长,受抑制程度为根>发芽势>发芽率;镉(0.001 mmol/L~0.100 mmol/L)和锌(0.010 mmol/L~1.000 mmol/L)能够抑制番茄幼苗株高的增长和干物质的积累、降低叶绿素a、叶绿素b、叶绿素a b及叶绿素a/b值;番茄茎、叶含水量在高浓度处理(镉、锌营养液浓度分别为0.100 mmol/L和1.000 mmol/L)时明显降低;番茄根、叶中脯氨酸和谷胱甘肽含量均随镉、锌营养液浓度的提高而呈增加趋势,而可溶性糖含量只有当镉、锌营养液浓度分别为0.100 mmol/L和0.100 mmol/L、1.000 mmol/L时才上升。依据试验结果,作者讨论了重金属镉、锌对番茄幼苗根、叶中可溶性糖、脯氨酸和谷胱甘肽含量的作用。     

Effects of reduced glutathione supplementation in semen freezing extender on frozen-thawed bull semen and in vitro fertilization

During cryopreservation, spermatozoa may suffer cold and cryo-induced injuries ―associated with alterations in cell defense systems― that are detrimental to their function and subsequent fertility. This study aimed to determine the efficacy of supplementing the semen freezing extender with the antioxidant reduced glutathione (GSH) in cattle. Semen was collected from four bulls and diluted in a freezing extender supplemented with or without GSH (0, 1, 5, and 10 mM) before the cooling step of the cryopreservation process. After thawing, the quality of the frozen-thawed semen was investigated for motility, viability, acrosomal and DNA integrity, and subsequent embryo development after in vitro fertilization of bovine oocytes. Additionally, semen from one of the bulls was used to analyze semen antioxidative potential, sperm penetration into oocytes, male pronucleus formation rate, and embryo DNA integrity. The sperm quality varied among bulls after GSH supplementation. One bull had decreased sperm total motility, and two bulls had decreased sperm DNA integrity. GSH supplementation had positive effects on embryo development for three bulls. Two of them showed both improved cleavage and blastocyst formation rates, while the other one only showed an improved cleavage rate. We observed positive effects on early male pronucleus formation and no negative effects on DNA integrity and cell number in blastocyst stage embryos. Although the effect varies depending on individual bulls and GSH concentration, GSH supplementation in semen may improve in vitro embryo production from frozen semen.     

柞蚕丝素解酒保肝功能食品对小鼠酒精性肝损伤的防治作用研究

为了探讨柞蚕丝素解酒保肝功能食品对小鼠酒精性肝损伤的防治作用,将90只小鼠随机分为空白组、模型组、阳性药组、柞蚕丝素解酒保肝功能食品高、中、低剂量组,连续灌胃30d,测定肝脏MDA、GSH、TG含量,光镜观察肝组织形态学变化。结果显示,与模型组相比,高、中剂量组可明显降低肝匀浆MDA含量,阳性药组和中、低剂量组可明显降低肝匀浆TG含量。阳性药组和高剂量组可明显升高肝匀浆GSH含量升高,表明柞蚕丝素解酒保肝功能食品对小鼠解酒性肝损伤具有一定的防治作用。     

Selenium and vitamin E, natural antioxidants, protect rat cerebral cortex against dimethoate-induced neurotoxicity

Pesticides have been used in agriculture to enhance food production by eradicating unwanted insects and controlling disease vectors, nevertheless occupational exposure to high levels of these compounds can lead to neurodegenerative disorders, characterized by serious oxidative and neurotoxic effects. However, there is a lack of consensus as to which determinations are best used to quantify future risks arising from xenobiotic exposure and natural antioxidant interventions. Our study aims to determine the potential ability of selenium and/or vitamin E, used as nutritional supplements, to alleviate oxidative stress in cerebral cortex tissue induced by dimethoate, an organophosphorus pesticide. Adult Wistar rats were exposed either to dimethoate (0.2 g/L of drinking water), dimethoate + selenium (0.5 mg/kg of diet), dimethoate + vitamin E (100 mg/kg of diet), or dimethoate + selenium + vitamin E, for 30 days. Exposure to dimethoate increased malondialdehyde levels, protein carbonyl groups and advanced oxidation protein products, while Na⁺K⁺-ATPase, acetylcholinesterase and butyrylcholinesterase activities decreased in the cerebral cortex. An increase in glutathione peroxidase, superoxide dismutase and catalase activities and a decrease in glutathione, non-protein thiols and vitamin C levels were observed. Administration of selenium and/or vitamin E through the diet in dimethoate treated rats ameliorated the biochemical parameters cited above. The histological findings confirmed the biochemical results. The model of this study that we employed characterized the relationships between dimethoate-induced neurotoxicity and its alleviation by natural antioxidants like selenium and vitamin E. These elements may be considered beneficial for the protection of cerebral cortex against injury induced by dimethoate.     

Avermectin exposure induces apoptosis in King pigeon brain neurons

The effect of avermectin was studied on King pigeon brain nerve cells by cytotoxicity [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide, MTT] and apoptosis [acridine orange/ethidium bromide (AO/EB) assay, transmission electron microscope (TEM) evaluation, measurement of mitochondrial membrane potential (Δψm), phosphatidylserine (PS) exposure, caspases activities, DNA fragmentation, reactive oxygen species (ROS) and caspase-3 mRNA expression] within the 2.5–10 μg L⁻¹ concentration-range. The results revealed that within the concentrations of 2.5–10 μg L⁻¹, avermectin showed obvious cytotoxicity and induced apoptosis in a dose-dependent manner to neurons of King pigeon in vitro. Cell viability were 99.93 ± 8.52%, 82.02 ± 4.99% and 78.23 ± 5.67% after 24 h of treatment with avermectin at the concentrations of 0, 2.5 and 5 μg L⁻¹, which decreased to 56.36 ± 2.17% of 10 μg L⁻¹. Treated cells showed typical apoptosis morphological changes including cytoplasmic vacuolation, chromatin condensation, unclear nuclear membrane and decreased/swollen mitochondria. Typical biochemical hallmarks of apoptosis including Δψm loss, PS exposure, activations of caspase-3, caspase-8 and caspase-9, DNA fragmentation were observed too. Moreover, the levels of ROS in the avermectin treatment groups increased significantly compared to control group. Furthermore, the caspase-3 mRNA levels increased significantly following AVM treatment. In conclusion, our experimental results show that avermectin has cytotoxicity to brain neurons of King pigeon in vitro and the mechanism of neurotoxicity induced by avermectin is closely related to apoptosis.     

The Cd‐tolerant rice mutant cadH‐5 is a high Cd accumulator and shows enhanced antioxidant activity

To investigate the mechanism of cadmium (Cd) detoxification in rice (Oryza sativa L.), a Cd‐tolerant mutant cadH‐5, obtained by an Agrobacterium tumefaciens‐based gene‐delivery system, was used for a Cd‐tolerance and accumulation study. After 15 d of exposure to 0.75 mM CdCl₂, significant phenotypic differences were observed between the wild type (WT) and cadH‐5. When exposed to 0.5 mM CdCl₂, higher Cd levels were accumulated in cadH‐5 root cell wall, root cytosol, and membranes than those in WT. However, Cd concentrations in root tissues varied in both WT and cadH5. No significant difference of hydrogen peroxide (H₂O₂) concentrations was observed between WT and cadH‐5, while contents of cell‐wall polysaccharides and phytochelatins (PCs) in the mutant were higher compared to WT. The ratios of reduced glutathione to oxidized glutathione (GSH : GSSG) and ascorbate to dehydroascorbate (ASC : DHA) were lower in WT than in cadH‐5, while the NADPH : NADP⁺ ratio was different to the ratios of GSH : GSSG and ASC : DHA; the ascorbate peroxidase (APX, EC 1.11.1.11), glutathione peroxidase (GR, EC 1.6.4.2), dehydroascorbate reductase (DHAR, EC 1.8.5.1), and monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) activities were lower in WT compared to cadH‐5. Our results indicate that under long‐term Cd stress, cadH‐5 plants can accumulate more Cd with more PC. Also, the redox status of ASC‐GSH cycle was more inhibited in WT than in cadH‐5 plants, rendering WT less able to scavenge reactive oxygen species (ROS). The cadH‐5 mutant maintains relatively high ASC, GSH, and NADPH concentrations, ratios of ASC : DHA, GSH : GSSG, and NADPH : NADP⁺, as well as antioxidative enzymatic activities and PC concentrations. Thus, it is tolerant of relatively high Cd accumulation.     

Oxidative damage in bone and erythrocytes of suckling rats exposed to 2,4-dichlorophenoxyacetic acid

Nowadays, people’s exposure to pesticides such as 2,4-dichlorophenoxyacetic acid (2,4-D) is increasing continuously. This compound is suspected to produce in excess free radicals which have adverse effects on human health causing several cell alterations in the organism. The present study investigated oxidative stress in the bone and erythrocytes of suckling rats whose mothers were treated with 2,4-D. Experiments were carried out on adult Wistar rats given 600 mg/L of 2,4-D in their drinking water from the 14th day of pregnancy until day 14 after delivery. Exposing dams to 2,4-D caused disorders in the bone of their progeny. Indeed, it induced changes in bone mineralization, especially calcium and phosphorus levels. Moreover, total tartrate-resistant acid phosphatase, which reflected bone resorption, was enhanced while total alkaline phosphatase, which reflected bone formation, was reduced suggesting that this herbicide accelerated bone resorption. The impairment of bone function corresponded histologically.Rats exposed to 2,4-D showed in both bone and erythrocytes an increase in malondialdehyde, advanced oxidation protein products and protein carbonyl levels and a decrease in non-enzymatic (glutathione, non-protein thiol, and vitamin C) and enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) antioxidant system.     

化合物YF-206防除乙草胺药害研究

本文采用土培法对本课题组所合成的化合物5-二氯乙酰基-6-甲基-9-氧杂-1,5-二氮杂二环[4.3.0]壬烷(YF-206)进行了室内活性测定实验。当化合物YF-206浓度为25mg/kg时,玉米各项生长指标恢复率达到最大,其株高、株鲜重的恢复率分别为:55.39%和55.86%;玉米幼苗根部GSH含量增幅达到50.59%,叶片中增幅为26.02%,玉米根部GST比活力为2.694 nmol/s/mg。实验结果表明化合物YF-206对玉米有较好的安全活性,能在一定程度上解除乙草胺对玉米的药害。