Synergistic and antagonistic effects of atrazine on the toxicity of organophosphorodithioate and organophosphorothioate insecticides to Chironomus tentans (Diptera: Chironomidae)

The acute toxicities of two organophosphorodithioate (dimethoate and disulfoton) and two organophosphorothioate (omethoate and demeton-S-methyl) insecticides were evaluated individually and in binary combination with the herbicide atrazine using fourth-instar larvae of the aquatic midge, Chironomus tentans. Atrazine alone up to 1000 μg/L did not show significant toxicity to the midges in a 48-h bioassay. However, atrazine concentrations as low as 1 μg/L in combination with dimethoate at EC₂₅ (concentration to affect 25% of tested midges), 100 μg/L in combination with disulfoton (EC₂₅), and 10 μg/L in combination with demeton-S-methyl (EC₂₅) significantly enhanced the toxicity of each organophosphate insecticide. In contrast, atrazine concentrations of 10 μg/L and above in combination with omethoate (EC₂₅) significantly decreased the toxicity of the insecticide. Biochemical analysis indicated that increased toxicity of dimethoate, disulfoton, and demeton-S-methyl in binary combination with atrazine correlated to the increased inhibition of acetylcholinesterase. Furthermore, cytochrome P450-dependent O-deethylation activity in the midges exposed to atrazine at 1000 μg/L was 1.5-fold higher than that in the control midges. Thus, atrazine appeared to induce cytochrome P450 monooxygenases in the midges. Elevated cytochrome P450 monooxygenase activity may increase the toxicities of dimethoate, disulfoton, and demeton-S-methyl by enhancing the oxidative activation of dimethoate into omethoate, and disulfoton and demeton-S-methyl into their sulfoxide analogs with increased anticholinesterase activity. In contrast, atrazine reduced the toxicity of omethoate possibly by enhancing the oxidative metabolic detoxification since omethoate does not require oxidative activation.     

不同类型有机物料的有机磷组成及生物有效性

[目的]研究不同有机物料的有机磷组成及其作为磷源施用后的供磷能力,为化肥磷的有机替代奠定理论基础.[方法]供试有机物料包括粪肥类(猪粪、羊粪)、绿肥类(豌豆、苜蓿和绿豆)、秸秆类(小麦秸秆、玉米秸秆和油菜秸秆).分析了8种有机物料的全磷、有机磷含量和C/P值,采用Bowman-Cole方法测定了有机磷中的活性(LOP)...     

CYP450 epoxygenase/EET pathway attenuates adipose inflammation of obese mice through HIF-1α

AIM To investigate the effects of cytochrome P450 （CYP450） epoxygenase/epoxyeicosatrienoic acid （EET） pathway on insulin resistance in obese mice, and to explore the possible mechanisms. METHODS High-fat diet-induced obesity model was established in C57BL/6Cnc mice, and the obese mice were randomly divided into 3 groups, including obesity group （treated with saline; n=10）, EET group （treated with 11,12-EET; n=10） and EET inhibitor 14,15-epoxyeicosa-5（Z）-enoic acid （EEZE） group （n=10）. Normal C57BL/6Cnc mice （n=10） treated with saline served as control. Protein expression of CYP2J2 （one of CYP450 epoxygenases） and hypoxia-inducible factor-1α （HIF-1α） was measured by Western blot. Vessel-like structure was detected by immunofluorescence staining. The serum levels of insulin, tumor necrosis factor-α （TNF-α）, interleukin （IL）-1β, IL-6 and monocyte chemoattractant protein-1 （MCP-1） were measured by ELISA. RESULTS In obese mice, homeostasis model assessment of insulin resistance （HOMA-IR） values were increased, the protein level of CYP2J2 was reduced, and the protein level of HIF-1α was increased in adipose tissues as compared with the controls （P<0.05）. The serum levels of MCP-1, IL-1β, IL-6 and TNF-α were also significantly increased in obese mice （P<0.05）. After treatment with 11, 12-EET, the HOMA-IR values were decreased compared with vehicle-treated obese mice, HIF-1α expression levels were decreased in the adipose tissue, and the serum levels of MCP-1, IL-1β, IL-6 and TNF-α were reduced （P<0.05）. Immunohistochemical results of adipose tissue from vehicle-treated obese mice showed a marked decrease in vessel-like structures （CD31-positive） compared with normal control mice （P<0.05）. EET treatment significantly increased the newly formed vessel-like structures in the visceral adipose tissues of obese mice as compared with vehicle-treated obese mice （P<0.05）. CONCLUSION High-fat diet-induced obesity and insulin resistance are closely related to the CYP450 pathway. Exogenous EETs effectively decrease obesity-induced insulin resistance possibly through pro-angiogenesis and attenuation of hypoxia and inflammation.     

三种内生真菌与大花蕙兰共生对矿质营养吸收的影响

以从兰科植物出的内生真菌与大花蕙兰接种,均能形成菌根,其中ＧＣ９４１和ＧＣ９４５两种菌只侵染根的表皮细胞,在细胞内呈菌丝结结构,而ＧＣ９３４菌在侵染前期同前两和种真菌,后期菌丝可部分侵染皮层细胞,并呈疏松的分枝状结构。３种内生真菌可使幼苗茎叶干重比增施矿质营养但不接种真菌的处理（ＣＫ２）提高１７３．２％－２５０．１％,并对植株吸收Ｎ,Ｐ,Ｋ养分有促进作用,其中ＧＣ９４５菌使幼苗吸收Ｎ和Ｋ的量比ＣＫ     

旋毛虫p53糖蛋白抗原研究进展

旋毛虫p53糖蛋白是旋毛虫肌幼虫排泄分泌抗原的主要抗原组分之一,具有肌幼虫期特异表达特性,主要定位在肌幼虫β-杆细胞.不同旋毛虫种p53糖蛋白氨基酸序列相对保守,但抗原性有差异,在同一种内变异极少,具有种及属特异性抗原表位.论文就旋毛虫p53糖蛋白抗原的分子结构、不同发育时期的特异性表达、抗原性等方面的研究进展进行综述...     

中国西部草地生态系统可持续发展的探讨

针对在西部大开发战略背景下中国西部草地生态系统的可持续发展问题,从可持续发展研究的背景出发,参阅国内外对可持续发展的理解和研究,在对中国西部草地生态系统的特点、利用情况、存在问题进行分析的基础上,参照可持续发展思想、千年生态系统综合评估思想和社会经济理论,提出实现中国西部草地生态系统可持续发展就是要处理好西部草地自然资源和生态环境子系统、经济发展子系统、科技文化子系统、人口子系统、草地资源利用子系统和草地管理子系统之间的关系,解决好系统相悖的问题,促进各个子系统耦合,使西部草地生态系统全面协调可持续发展。     

EIAV Rev蛋白拮抗eqTRIM5α介导的AP-1信号通路的机制研究

为探究马传染性贫血病毒(EIAV)附属蛋白Rev负调控Tripartite motif-containing protein 5α(TRIM5α)介导的AP-1信号通路的机制,本研究将pEIAV-Rev-HA和pcDNA3.1质粒分别与含TRIM5α基因的质粒及pGL3-AP-1-Luc(AP-1报告质粒)共转染HEK 293T细胞,采用荧光素酶试验检测Rev对TRIM5α激活的AP-1信号通路的影响;将pEIAV-Rev-HA和pcDNA3.1质粒分别与含TAK1、TAB2、P38和c-Jun基因的质粒及pGL3-AP-1-Luc共转染HEK 293T细胞,采用荧光素酶试验检测Rev对TRIM5α下游转导分子(TAK1、TAB2、P38、c-Jun)激活的AP-1信号通路的影响;将pEIAV-Rev-HA和pcDNA3.1质粒分别与含TAK1、TAB2、P38基因的质粒共转染HEK293T细胞,利用western blot试验分别检测TAK1、TAB2、P38的表达水平;将pEIAV-Rev-HA和pcDNA3.1质粒分别与含P38基因的质粒共转染HEK 293T细胞后加入蛋白酶体抑制剂MG132,利用western blot检测P38蛋白的表达情况。结果显示,共转染EIAV-Rev-HA实验组中TRIM5α对AP-1的激活倍数为0.4,而共转染pcDNA3.1对照组中相应的激活倍数为26.0;共转染pEIAV-Rev-HA实验组中,TAK1、TAB2、P38和c-Jun对AP-1信号通路的激活倍数分别为7.7、0.1、0.6、9.8,而共转染pcDNA3.1对照组中对AP-1信号通路的激活倍数分别为60.0、1.5、6.3、12.0;转染pEIAV-Rev-HA+pP38-Flag组与转染pcDNA3.1+pP38-Flag组相比,前者P38蛋白的表达量显著降低;加入蛋白酶体抑制剂组则恢复了P38蛋白的表达。上述结果表明,EIAV Rev显著下调eqTRIM5α及其下游转导分子TAK1、TAB2、P38激活的AP-1信号通路,但不显著下调c-Jun激活的AP-1信号通路;EIAV Rev通过蛋白酶体途径降解P38蛋白的表达而抑制eqTRIM5α激活的AP-1信号通路。本研究结果为理解EIAV与宿主蛋白相互作用提供参考依据。     

禽呼肠孤病毒P17蛋白基因在大肠杆菌中的表达及其ELISA检测方法的建立

用设计合成的1对跨越禽呼肠孤病毒（ARV）P17非结构蛋白基因完整开放阅读框（ORF）的特异性引物，对ARVS1133株进行了RT-PCR扩增。扩增产物与pGEX-4T-1原核表达载体连接后，转化大肠杆菌BL21感受态细胞。经0．2mmol／LIPTG诱导，表达的融合蛋白分子质量为42.4ku，占茵体总蛋白的34％。表达产物P17蛋白经不同浓度尿素纯化后，纯度达到85％。Western-blotting显示，纯化的P17蛋白能与感染ARV的阳性血清反应，说明其具有抗原性。以此重组蛋白为包被抗原初步建立了用于鉴别检测ARV活病毒感染与灭活疫苗免疫的SPF鸡血清的ELISA。     

Quantification of dietary calcium requirement of fingerling Heteropneustes fossilis based on growth,feed conversion efficiency,mineralization and serum alkaline phosphatase activity

Seven isonitrogenous (400 g/kg crude protein) and isocaloric (17.89 kJ/g gross energy) purified diets (casein‐gelatin based) with different concentrations of calcium (0, 1, 2, 3, 4, 5 and 6 g/kg) supplemented with calcium lactate at the levels of 0, 5.4, 10.8, 16.3, 21.8, 27.27 and 32.73 g/kg were prepared and fed for 12 weeks to triplicate groups of Heteropneustes fossilis (7.46 ± 0.03 g) to determine the optimum dietary calcium requirement. Analysed values of calcium in the diets were 2.41, 3.82, 4.56, 5.99, 6.71, 7.40 and 8.19 g/kg, respectively. Absolute weight gain, specific growth rate, protein retention efficiency, protein gain and feed conversion ratio of fish fed diets with increasing levels of dietary calcium improved up to 5.99 g/kg and then levelled off. Whole‐body protein, moisture and ash contents improved up to 5.99 g/kg dietary calcium and stabilized thereafter. However, whole‐body fat exhibited reverse pattern and decreased with incremental levels of dietary calcium up to 5.99 g/kg. Whole‐body and vertebrae mineralization was also significantly affected (p < .05) by the increasing dietary calcium levels. Alkaline phosphatase activity improved significantly (p < .05) up to 6.71 g/kg, and no change was recorded beyond this level. Serum calcium and phosphorus concentrations were not influenced (p > .05) by dietary calcium levels. The Ca–P ratio remained static in the whole body, vertebrae and serum. Broken‐line regression analysis of data obtained on growth, mineralization and serum ALP activity against increasing levels of dietary calcium reflected the optimum calcium requirement between 5.77–6.81 g/kg diet.