草甘膦水剂分析方法研究

前言关于草甘膦(glyphosate)的分析方法,国内外报道有高效液相色谱法、亚硝化紫外分光光度法、络合滴定法、亚硝化滴定法、柱层析比色法。目前我国生产草甘膦水剂的厂家,主要采用络合滴定法和亚硝化紫外分光光度法,个别采用亚硝化滴定法和柱层析分光光度法。这些方法受产品中的杂质、添加剂等干扰,使得测定结果偏高,不能反映草甘膦水剂的真实含量,难以科学地指导生产,也无法控制产品质量。     

重氮化滴定法的要点

在农药分析中常常采用亚硝酸钠滴定法,又称重氮化滴定法。测定含有氨基和硝基的化合物,例如:防治麦类锈病使用的对氨基苯磺酸钠可用亚硝酸钠标准溶液直接滴定来测定其含量;有机磷杀虫剂对硫磷(NaSO_3—(?)—NH_2·2H_2O),     

黄杨组织中水分、不饱和脂肪酸、维生素C等与其耐寒性关系

本试验选取种植于包头市内五个不同生境中的三个黄杨品种,在冬季、夏季分别测定与耐寒性相关的生理指标,如水分、不饱和脂肪酸及维生素C等,以分析其耐寒性差异。结果表明:组织中水分含量呈夏季多冬季少的趋势,从含量的差异中可以判别黄杨耐寒性的大小,水分含量可以作为黄杨耐寒性的生理指标;不饱和脂肪酸变化没有明显规律,仅能作为黄扬耐寒性的参考指标。维生素C也呈现夏多冬少趋势,变化较为明显,可作为黄杨耐寒性的生理指标。以上几项综合得出:三个黄杨品种的耐寒性强弱依次是锦熟黄杨最强,朝鲜黄杨次之,小叶黄杨最弱。     

奶和茶不适宜一起喝

茶叶含有儿茶素与β-胡萝卜素、维生素C、维生素E等，多项实验证明，茶叶能清除自由基、延缓衰老、预防癌症。     

乙烯利含量最新国家标准化学滴定分析方法的初探

本文讨论了化学滴定法测定乙烯利含量过程中,化学试剂氢氧化钠的纯度（即杂质NaCO3）对乙烯利含量的影响,并提出了对试剂和氢氧化钠标准溶液的要求。     

服药忌食橘子

橘子含有丰富的果酸和维生素C,服用维生素K、磺胺类药物、安体舒通、氨苯喋啶和补钾药物时,均应忌食橘子。橘子中丰富的营养成分有降血脂、抗动脉粥样硬化等作用,对于预防心血管疾病的发生大有益处。橘汁中含有一种名为"诺米     

蝗虫可作为药用昆虫资源

蝗虫,又称蚂蚱、蚱蜢。是我国常见的一种大害虫,但就其本身而言是可以作为药用昆虫资源变害为益来利用的。蝗虫含蛋白质、脂肪、脂肪酸、维生素 A、维生素 B、维生素 C等以及其它微量元素,可鲜用或干燥入药,具有止咳平喘、止痉、解毒、透疹等功能。主要用     

不同降水年型下秸秆带状覆盖对西北旱地马铃薯品质和产量的影响

为探明不同覆盖方式对马铃薯品质和产量的影响，于2019—2021年在西北半干旱雨养农业区设置秸秆带状覆盖(SM)、地膜覆盖(PM)、无覆盖露地(CK)3个处理，通过测定马铃薯块茎维生素C、淀粉、直链淀粉、还原糖、粗蛋白含量及产量指标，研究不同覆盖方式对马铃薯品质和产量的影响。结果表明：不同降水年型下秸秆带状覆盖和地膜覆盖均可以显著改善马铃薯的品质，丰水年(2019年和2020年),与CK相比，SM处理显著提高了块茎淀粉、直链淀粉的含量，增幅分别为15.2%和31.9%,PM处理显著提高了粗蛋白含量，增幅为26.6%;平水年(2021年),与CK相比，SM处理维生素C、还原糖含量分别显著提高20.4%和5.1%,PM处理维生素C、还原糖、粗蛋白含量分别显著提高35.2%、8.3%、14.6%;覆盖方式对马铃薯品质的影响整体表现为SM>PM。主成分分析和灰色关联度分析表明，SM和PM处理均可提高马铃薯品质，且SM处理马铃薯品质与产量关联度高于PM处理，SM处理下淀粉、直链淀粉含量与产量的关联度最高。覆盖栽培方式均显著提高了马铃薯鲜薯产量，SM、PM分别较CK提高13.7%～19.5%...     

广西崇左油梨叶部炭疽病病原菌分离与鉴定

<正>油梨(Persea americana Mill.)又名鳄梨、酪梨，原产于墨西哥与中美洲高原，其营养丰富，含有多种维生素、脂肪酸、蛋白质、维生素等^[1]。随着油梨的规模化种植，病虫害问题也随之发生，炭疽病是油梨叶部常见病害之一。国外有学者报道油梨果实炭疽病病原菌有Colletotrichum gloeosporioides^[2]、C. acutatum^[3]等。近日，我国学者报道来自海南儋州的油梨炭疽菌病原菌为C. siamense^[4]，还有学者分析了购自广州一水果商铺油梨果(进口自秘鲁)上的炭疽病病原菌种类为果生刺盘孢(C. fructicola)^[5]。     

用抗氧化剂防治多种作物灰霉病和菌核病

本研究通过测试18种抗氧化剂(游离基清除剂)防治灰霉病的效果表明,苏达灭羟甲苯、丹宁酸、维生素C和二甲亚砜(1.0毫克分子浓度)能控制番茄果实灰霉病,也能控制黄瓜果实灰霉病(苏达灭羟甲苯除外),一些氧化剂(苯甲酸与苏达灭羟甲苯或去甲二氢愈创木酸,维生素C与苏达灭羟甲苯或丙没食子酸等)复配后表现显著的附加效果。增效剂维C和柠檬酸提高了几种抗氧化剂的防治效果。氧化剂中的葡糖酸内酯、丙没食子酸和硫脲对核盘菌的抑病效果分别达76％、59％和51％。     

基于DPPH法对紫茎泽兰提取物抗氧化活性的研究

以维生素c为对照,采用DPPH法研究紫茎泽兰叶和茎醇提物的抗氧化活性,并计算它们的Ic20。结果表明：1．6mg／mL紫茎泽兰叶和茎的醇提物有很好的清除能力,清除率均达到80％以上,相当于0．10mg／mL维生素C的清除率;紫茎泽兰叶和茎的Ic50为0．3．0．7mg／mL,维生素c为0．04mg／mL。说明紫茎泽兰叶的清除能力强于茎,紫茎泽兰清除自由基的能力为维生素c的1／10。总之,紫茎泽兰具有较强的抗氧化活性。     

Deltamethrin induced alterations of hematological and biochemical parameters in fingerlings of Catla catla (Ham.) and their amelioration by dietary supplement of vitamin C

The present study was carried out to investigate the sub-lethal toxicity of technical grade deltamethrin (a synthetic pyrethroid) of concentration 1.61 μg/L (1/3rd of 96 h LC₅₀) on hematological and biochemical parameters of catla (Catla catla) fingerlings and its amelioration through dietary vitamin C. The deltamethrin exposed fishes were fed with different levels of supplemented vitamin C such as 50, 250, 500 and 1000 mg/kg diet to see its ameliorating effect by assaying hematological parameters viz. total erythrocyte count (TEC), total leukocyte count (TLC), hemoglobin content (Hb), total serum protein, albumin, globulin, albumin–globulin ratio and biochemical parameters such as lactate dehydrogenase (LDH), acetylcholine esterase (AChE), alanine amino transferase (ALT), aspartate amino transferase (AST), total adenosine triphosphatase (ATPase), magnesium adenosine triphosphatase (Mg²⁺-ATPase) and sodium potassium adenosine triphosphatase (Na⁺, K⁺-ATPase) activities. The finding of this study showed that deltamethrin had negative effect on the hematological and biochemical parameters of Catla catla. The experimental group, which was exposed to deltamethrin and fed with normal diet showed significantly lower values (P ? 0.05) of all parameters studied except ALT activity. This might be due to possible disruption of hematopoiesis and proteosynthesis. However, the fish fed with varied concentration of vitamin C in diets neutralized the toxic effect of deltamethrin, as evidenced by significantly lowered hematological and biochemical response. Vitamin C @ 1000 mg/kg diet was the most effective in amelioration of harmful effect of deltamethrin on hematological and biochemical parameters of catla fingerlings. The result suggests that vitamin C can be effectively used to neutralize the toxic effect of deltamethrin on catla.     

Chronic chlorpyrifos-induced oxidative changes in the testes and pituitary gland of Wistar rats: Ameliorative effects of vitamin C

Chlorpyrifos (CPF), a chlorinated organophosphate insecticide that is widely used in agriculture and public health, has been implicated in male reproductive toxicity. Apart from acetylcholinesterase inhibition, CPF has been shown to induce changes characteristic of oxidative stress. Therefore, the aim of the present study was to evaluate the effects of vitamin C on oxidative changes in the testes and pituitary gland of rats chronically exposed to CPF. Twenty adult male Wistar rats were divided into four groups of five animals each: Group I (S/oil) received soya oil (2 ml/kg); Group II (VC) was administered with vitamin C (100 mg/kg); Group III (CPF) was given CPF (10.6 mg/kg; ∼1/8th LD₅₀); Group IV (VC + CPF) was pretreated with vitamin C (100 mg/kg) and then given CPF (10.6 mg/kg), 30 min later. The regimens were administered orally by gavage once daily for 15 weeks. Thereafter, the rats were sacrificed and the testes and pituitary glands were evaluated for the concentration of malonaldehyde (MDA) and activities of superoxide dismutase (SOD) and catalase (CAT). The result shows that CPF increased MDA concentration and reduced activities of SOD and CAT, which were ameliorated by pretreatment with vitamin C.     

Effect of paraoxon-methyl and parathion-methyl on DNA in human lymphocytes and protective action of vitamin C

The molecular basis of the genotoxicity of the commonly used organophosphorus insecticide, parathion-methyl is poorly understood and there is a lack of information on the possible effects of its metabolic conversion products. In the present work the action of parathion-methyl and its immediate metabolite paraoxon-methyl on DNA in human lymphocytes was compared using the comet assay. Parathion-methyl at 25 and 75 µM did not cause any significant changes but at 200 µM a significant increase in the tail moment was observed as compared with the control. Paraoxon-methyl at 25, 75 and 200 µM evoked dose-dependent DNA damage measured as a significant increase in comet tail moment of lymphocytes. The change evoked by paraoxon-methyl at 200 µM was much more pronounced than that by parathion-methyl at the same concentration. To search for the mechanism underlying the observed effect, the action of a well-known antioxidant, vitamin C, along with parathion-methyl and paraoxon-methyl was studied. The vitamin at 10 and 50 µM reduced the DNA-damaging activity of paraoxon-methyl at all its concentrations. The results indicate that the reported genotoxic effects of parathion-methyl could be mainly attributed to its metabolite paraoxon-methyl. The protective action of vitamin C suggests that paraoxon-methyl may cause oxidative DNA damage. © 1999 Society of Chemical Industry     

1,2-苯二硫酚衍生-高效液相色谱法检测二硫代氨基甲酸酯类化合物的方法改进

通过添加抗氧化剂四氢呋喃和抗坏血酸,对传统的二硫代氨基甲酸酯类化合物检测方法——1,2-苯二硫酚衍生-高效液相色谱法进行了优化和改进,并用4种常用二硫代氨基甲酸酯类杀菌剂[70%代森锰锌可湿性粉剂(WP)、68%精甲霜锰锌水分散粒剂(WG)、68%霜脲锰锌WG和55%唑醚代森联WG]对该方法进行了验证。结果表明:当1,2-苯二硫酚浓度为12 mmol/L、代森锰锌用乙二胺四乙酸二钠(EDTA,p H 9.3)及代森联用二乙基三胺五乙酸(DTPA,p H 10.0)解络合、且同时添加体积分数为4%的四氢呋喃和40 mg/L的抗坏血酸时衍生化条件最优。除55%唑醚代森联WG外,其他3种商品杀菌剂待测液在衍生化后48 h内均保持稳定且相对标准偏差5%,满足测试要求。该方法操作简便快捷,检出目标物明确,不受二硫代氨基甲酸酯类杀菌剂常见代谢物乙撑硫脲及二硫化碳的影响,检测效率高,适用于该类杀菌剂的批量测试。     

Chlorpyrifos-induced oxidative stress and histological changes in retinas and kidney in rats: Protective role of ascorbic acid and alpha tocopherol

This study was undertaken to evaluate the antioxidant effect of vitamins C and E against oxidative stress, apoptosis and histological changes of kidney and retina in CPF-treated rats. Forty male Sprague-Dawley rats were divided into four groups including the control group, the group treated orally with a single dose of CPF (63 mg/kg b.w.), the group injected intramuscularly (i.m.) with vitamin C (250 mg/kg b.w.), and intraperitonealy (i.p.) with vitamin E (150 mg/kg b.w.) daily for 7 days and the group treated with CPF (single dose) and injected with vitamins (for 7 days). The results showed that CPF induced apoptosis and severe oxidative stress as indicated by the significant increase in MDA and sFasL concentration and the significant decrease in GSH concentration in serum. Co-administration of vitamins C and E ameliorate these toxic effects and improved the histological pictures of kidneys and retinas. It could be concluded that combined administration of vitamins C and E is useful in the routine therapy for the protection against tissue damage induced by CPF.     

青枯雷尔氏菌温度相关致病基因yqhE功能研究

不同温度下青枯雷尔氏菌表达谱PPI网络分析发现,yqhE可能是青枯雷尔氏菌新的温度相关致病基因。克隆青枯雷尔氏菌CBM613的yqh E基因,结果发现该基因长度为831 bp,共编码276个氨基酸。基因敲除结果显示,28℃培养的yqhE突变株较野生型菌株致病力降低,病程延长,但并未彻底丧失致病力。20℃和28℃培养的yqh E突变株维生素C的生物合成皆被抑制;与28℃相比,20℃培养下野生型菌株维生素C的合成能力降低。突变株在20℃和28℃培养下甲基乙二醛（MG）和丙二醛（MDA）明显积累,其中20℃积累更多;20℃培养的野生型菌株MG和MDA比28℃积累更多。维生素C的生物合成被抑制导致青枯雷尔氏菌自由基清除能力减弱与氧化应激反应增强,MG和MDA积累产生细胞毒性,上述结果可能与28℃培养的突变株致病力减弱,20℃培养的野生型菌株致病力丧失有关。综上结果表明yqhE是青枯雷尔氏菌温度相关致病基因。     

Protective effect of vitamin C against chlorpyrifos oxidative stress in male mice

Pesticides may induce oxidative stress leading to generate free radicals and alternate antioxidant or oxygen free radical scavenging enzyme system. This study was conducted to investigate the acute toxicity of chlorpyrifos toward male mice and the oxidative stress of the sub-lethal dose (1/10 LD₅₀) on the lipid peroxidation level (LPO), reduced glutathione content (GSH) and antioxidant enzymes; catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glucose-6-phosphate dehydrogenase (G6PD), and glutathione-S-transferase (GST) activities. Also, the protective effects of vitamin C (200 mg/kg body weight, bw) 30 min before or after administration of chlorpyrifos were investigated. The results demonstrated that the LD₅₀ value of chlorpyrifos was 134.95 mg/kg bw. The oral administration of 13.495 mg/kg chlorpyrifos significantly caused elevation in LPO level and the activities of antioxidant enzymes including CAT, SOD and GST. However, GPx activity remained unchanged, while the level of GSH and G6PD activity were decreased. Vitamin C treatment to chlorpyrifos intoxicated mice decreased LPO level and GST activity, normalized CAT, SOD and G6PD activities, while GSH content was increased. We conclude that vitamin C significantly reduces chlorpyrifos-induced oxidative stress in mice liver and the protective effect of the pre-treatment with vitamin C is better than the post-treatment.     

植物生长调节剂对马铃薯块茎淀粉含量及品质的影响

大田栽培条件下,以马铃薯(Solanum tuberosum L.)荷兰212为材料,叶面喷施不同植物生长调节剂,通过比较块茎中转化酶、淀粉酶活性变化以及蔗糖、淀粉、维生素C等含量变化的差异,研究喷施植物生长调节剂对马铃薯块茎品质的调控效应.结果表明:在块茎生长过程中,2-N,N-二乙氨基乙基己酸酯(DTA-6)对块茎...     

Vitamin K requirement in Danish anticoagulant-resistant Norway rats (Rattus norvegicus)

Resistance to warfarin has been connected to an increase in dietary requirement for vitamin K in British strains of the Norway rat, Rattus norvegicus (Berk). This study examines vitamin K requirement of Danish anticoagulant-resistant Norway rats using a vitamin K deficient feeding test. Wild bromadiolone-resistant rats sampled from different localities in Denmark and rats from bromadiolone-resistant and susceptible laboratory strains were fed on a vitamin K deficient diet over a maximum period of 15 days. Development of vitamin K deficiency, measured as reduced blood-clotting capacity, took place in 43% of the Danish resistant rats and was independent of sex, treatment with supplementary vitamin K3 and sampling locality. Development of deficiency was slower for resistant rats that were supplemented with vitamin K3 prior to the feeding test, suggesting storage of the vitamin K in a vitamin body pool. Intraperitoneal administration of vitamin K1 revealed that 80 microg vitamin K1 kg(-1) bodyweight was sufficient to restore normal blood clotting activity in deficient rats, while 60 microg vitamin K1 kg(-1) bodyweight was insufficient. We conclude that vitamin K requirement is moderately increased in Danish homozygous resistant rats whereas heterozygous resistant rats only have a minor increase in vitamin K requirement compared with susceptible rats. We found no indication of different resistance types being present in our test material since vitamin K requirement was not different between rats from separate sampling localities.