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171.
Both pentachlorophenol and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) had been studied widely because of their probable anti-estrogenic activity. Sodium pentachlorophenol (PCP-Na), as a industrial product used in many fields, usually contains a trace of TCDD. The aim of this study was to assess the anti-estrogenic effect of PCP-Na in juvenile goldfish (Gurassius auratus) hepatocyte cultures using vitellogenin (VTG) as the biomarker. The ID50 of PCP-Na was investigated and then a series of concentrations (0.001 0.5 μg/ml) of PCP-Na were evaluated to estimate the anti-estrogenic activity. Results showed that PCP-Na was cytotoxic for hepatocytes even at very low concentration 〈1.21 μg/ml, and it could not induce VTG at any concentrations tested. Since it failed to stimulate VTG production, the possibility of its anti-estrogenic effect was tested, and a well-known anti-estrogenic compound-tamoxifen was used as positive control. PCP-Na caused a reduction in VTG synthesis in juvenile goldfish (Carassius auratus) hepatocytes at concentrations 〉0.1μg/ml when co-exposure with 1μg/ml 17β-estradiol (E2), making its anti-estrogenic activity approximately as potent as tamoxifen. Our results indicate that PCP-Na can act as negative modulators of estrogenic function in juvenile goldfish (Carassius auratus) hepatocytes.  相似文献   
172.
微生物絮凝剂产生菌的初步筛选及条件试验   总被引:5,自引:1,他引:4  
从活性污泥中筛选到18株絮凝剂产生菌,经复筛得到一株高效絮凝剂产生菌L-3.分别研究了碳源、氮源、无机盐、初始pH值、培养温度等对其产生絮凝剂的影响.结果表明,葡萄糖、玉米淀粉是较好的碳源,酵母膏为最佳氮源,最适宜培养温度为30 ℃,初始pH为7~9,摇床转速为160 r/min.  相似文献   
173.
以废弃的冶金高炉渣为原料,采用混酸酸溶-水热合成法制备了光催化剂,并对其进行了SEM、UV-Vis、XRD、比表面积等物性测试分析;通过处理甲基橙模拟废水,探讨了制备过程中渣酸比、混酸配比、渣用量、溶渣时间等条件对高炉渣制光催化剂活性的影响。将所制光催化剂与P25光催化剂进行对比分析,结果表明,高炉渣制光催化剂不仅具有较高的光催化活性,而且制备成本低廉,仅为P25光催化剂的1/10,这对于冶金高炉渣的循环再利用及光催化氧化技术的工业化应用具有重要的实际意义。  相似文献   
174.
Dissolved iron (Fe) distribution and speciation was determined in water samples (0–200?m) collected in a coastal area near Terra Nova Bay during the austral summer of 2014. Nutrients, dissolved oxygen, chlorophyll-a, phytoplankton composition and prokaryotic biomass distribution were investigated in combination with measurements of the physical properties of the water columns and its dynamics. The dFe value was above the limiting growth concentration, ranging from 0.52 to 4.51?nM, and it showed a spatial variability with a horizontal length scale of about 10?km, according to the variability of the water column physical properties and to iron sources. The organic ligands (L) maintained the concentrations of dFe at levels much higher than the inorganic solubility of Fe, keeping it available for phytoplankton and the log K’FeL values found (from 22.1 to 23.6) highlighted the presence of complexes of differing stabilities.  相似文献   
175.
Introduction. This study aimed to examine the effectiveness of a physical activity (PA) program on weight control, physical fitness, occupational stress, job satisfaction and quality of life of overweight and sedentary employees in high-tech industries. Methods. Participants in the intervention group (n?=?37) were instructed to carry out a PA program at moderate intensity for 60?min/session, 3 sessions/week for 12 weeks. Those in the control group (n?=?38) received no PA program and were asked to continue their routine lifestyle. Evaluations were performed at baseline and at the end of the intervention. Results of structured questionnaires and blood biochemistry tests and evaluations of physical fitness were analyzed. Results. The PA program effectively reduced the number of risk factors for metabolic syndrome and body fat percentage, and improved physical fitness such as flexibility, muscular strength and endurance and cardiorespiratory endurance. The intervention also significantly decreased levels of serum triglyceride, total cholesterol and low-density lipoprotein cholesterol. Significant positive effects on work control, interpersonal relationships at work, global job satisfaction and quality of life were also demonstrated. Conclusion. This study showed that a PA program can be helpful in improving physical, physiological and psychological outcomes for overweight and sedentary employees in high-tech industries.  相似文献   
176.
采用室内恒温培养研究了施肥对不同农田土壤微生物活性的影响。结果表明,在红壤、水稻土和潮土中,土壤微生物量、土壤酶活性大小顺序均为有机肥配施无机肥处理>单施有机肥处理>单施无机肥处理,但对脲酶来说,其活性大小顺序为有机肥配施无机肥处理>单施无机肥处理>单施有机肥处理。从土壤类型来看,土壤微生物量碳、氮和土壤酶活性大小以水稻土最大,潮土次之,红壤最小。3种土壤的微生物量、土壤酶活性在培养的45~60d之间分别达到最大值,以后逐渐下降。部分单施无机肥处理的土壤微生物量、土壤酶活性最大值比单施有机肥处理、有机肥配施无机肥处理提前15d。相关分析表明,有机肥配施无机肥处理及单施有机肥处理,3种土壤的土壤微生物量碳、氮与土壤过氧化氢酶、转化酶、蛋白酶、脲酶及速效养分呈显著或极显著的相关性;单施无机肥处理中,土壤微生物量碳、氮与土壤过氧化氢酶、蔗糖转化酶、蛋白酶、脲酶显著或极显著相关,与部分速效养分相关不显著。  相似文献   
177.
用模拟酸雨淋洗土壤,造成土壤酸化和盐基流失,然后播种小麦(Triticumaestivum)。幼苗长至5片叶子时的测定表明:幼苗的生物量、叶片叶绿素含量和光合速率均降低,次生根减少,根系活动下降。酸化土壤对根系生物量和某些生理活动的影响大于对地上部的影响。  相似文献   
178.
NaCl,Na2CO3胁迫下星星草根际K^+,Na^+,Ca^2+的生理行为   总被引:16,自引:1,他引:16  
对星星草施加25~600mmol·L-1NaCl及12.5~200mmol·L-1Na2CO3的盐胁迫处理,分析其根际K+、Na+、Ca2+的生理行为.结果表明:Na2CO3对培养液中K+、Na+、Ca2+活度的影响大于NaCl,其中Na2CO3使Ca2+活度极度下降;营养液中K+、Na+、Ca2+活度与星星草根中K+、Na+含量密切相关,其中,根中K+、Na+含量与营养液中Ca2+活度和Na+活度平方之比即(Ca2+)/(Na+)2之间具有一致的曲线关系,根系环境中的(Ca2+)/(Na+)2对植物K+、Na+吸收有决定性作用.星星草地上部分K+、Na+含量与其根中K+、Na+含量也相关.根(DW)中K+在0.38~0.52mmol·g-1间可维持地上部分K+含量基本稳定.根中Na+含量较低时,地上部分Na+含量随根中含量升高而平缓上升.但根中Na+高至一定值时,地上部分Na+转而急剧上升,提示星星草在由根向上转运K+、Na+的过程中有一定调控作用.  相似文献   
179.
转Bt-cry1Ac棉花花粉对意大利蜜蜂生长发育的影响   总被引:3,自引:1,他引:3  
研究了取食转Bt-cry1Ac棉花花粉对意大利蜜蜂的影响,主要包括意大利蜜蜂的生长发育、体内酶活性的变化.结果发现,取食转Bt-cry1Ac基因棉花花粉的意大利蜜蜂与取食非转基因亲本棉花花粉的蜜蜂(CK)相比,4、5、6日龄幼虫体重差异不显著,幼虫及蛹的历期也没有明显差异.取食转Bt-cry1Ac基因棉花花粉的意大利蜜蜂6日龄幼虫体内的谷胱甘肽-S-转移酶、总蛋白酶活力与CK相比,没有显著差异.取食转Bt-cry1Ac基因棉花花粉的意大利蜜蜂幼虫体内的α-乙酸萘酯酶、乙酰胆碱酯酶活力极显著高于CK,强碱性、弱碱性类胰蛋白酶活力极显著低于CK,类胰凝乳蛋白酶活力显著低于CK.另外,采用酶联免疫(ELISA)方法在取食转Bt-cry1Ac基因棉花花粉的蜜蜂6日龄幼虫体内能够检测到Bt杀虫蛋白.表4参12  相似文献   
180.
Abstract:  Conservation biologists and others hypothesize that humankind's "ecological footprint" is affected not only by the sheer intensity of human activity but also by its spatial arrangement. We used a multivariate statistical model and state-level data to evaluate correlations between species imperilment and the level and spatial distribution of human settlement and infrastructure development in the United States. The level of human activity—measured by the number of people and households, incidence of roads, and intensity of nighttime lights—was significantly correlated with the ecological imperilment of species. Our regression models consistently showed that a 1% increase in the level of human activity across the United States was associated with about a 0.25% increase in the proportion of plant and animal species considered at risk of extinction by The Nature Conservancy. The distribution of human activity did not affect species imperilment. Our results point to rising levels of human activity—and not some particular (e.g., sprawling) distribution of human activity—as the most relevant anthropogenic factor explaining biodiversity loss in the United States.  相似文献   
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