乐果降解菌LGX1的筛选及其降解特性研究

通过富集培养,从连续施用农药乐果的土壤中分离得到一株具有较强降解有机磷农药乐果能力的细菌菌株LGX1,通过菌落形态观察及细菌的16SrDNA测序,对其进行了鉴定,同时初步研究了其降解性能。结果表明：该菌株为蜡状芽孢杆菌（Bacillus cereus）,在接种量为20%,乐果初始质量浓度为100mg·L-1,外加碳源葡萄糖质量分数为2%,温度为35℃,初始pH值为4时该菌株对乐果的降解能力最强;并且能在以辛硫磷、毒死蜱和三唑磷为唯一碳源的基础盐培养基中生长,且均比在以乐果为唯一碳源的基础盐培养基中生长的OD600值要高,初步推断菌株LGX1对有机磷农药的降解有一定的广谱性。     

水-硅油双相体系对多环芳烃降解菌的筛选及鉴定

选用水-硅油双相体系驯化筛选降解多环芳烃的优势菌株。筛选体系为：50mL无机盐溶液＋10mL硅油。从74瓶富集液中,对降解效果明显的富集液进行多环芳烃降解率的液相色谱定量测定。对蒽的降解率最高为45%;对荧蒽的降解率最高为99%,几乎全部降解,对苯并[a]芘的降解率为27%。筛选到一株能够高效降解蒽、菲、芘、荧蒽的菌株,编号LD29,鉴定结果为矢野口鞘氨醇杆菌LD29（Sphingobium yanoikuyae LD29）。富集液Y12对5种多环芳烃的降解效果同样很明显。     

生态毒理数据筛查与评价准则研究

化学品生态风险评价和水质基准研究需要大量生态毒理数据,由于目前关于化学品毒性效应的研究较多,不同文献对同一测试终点的报道常常存在一定的差异,数据选择不当会直接影响最终评价结果。为了降低专业人员在数据筛选过程中的主观影响,有必要制定一套科学合理、操作性强的数据筛查与评价准则。本文整理比较了美国、荷兰、德国和澳大利亚等4个国家的5个毒理数据筛查与评价方法,并以荷兰的CRED方法为主,结合另外4个筛选方法以及现有的水质基准推导指南和生态风险评价技术导则,从可靠性、相关性、精确性三个方面详细阐述了数据质量评价标准与使用规范。其中数据质量评价包括五个方面:(1)实验设计,包括测试标准、操作规程、数据有效性、对照组设置;(2)实验试剂的纯度及其杂质的物理化学性质;(3)受试生物的基本信息和来源;(4)暴露条件,包括试验系统、暴露浓度设置及变化、暴露时间、生物负荷;(5)数据分析,包括平行样、统计分析方法、浓度-效应关系、原始数据;数据使用规范主要考虑受试生物、测试终点和暴露场景与评价目标的相关性,以及生态风险评价和水质基准推导对数据精确性的要求。这些均可为我国从事生态风险评价和水质基准研究的工作人员提供有益借鉴,使数据筛选过程更加客观、统一,同时还可以作为毒理实验论文撰写依据,提高数据报道质量。     

环境风险评价中泄漏类重大事故的筛选研究

提出了采用"风险排序,以平均风险指数为尺度"来筛选项目中泄漏类重大事故的方法。该方法是对工业事故风险评估方法(ARAMIS)采用的风险严重度指数法的修正和应用范围的推广。借助已有事故发生的概率统计值,对所引概率进行修正,用Risk System预测得到的半致死浓度范围表征事故的后果。基于概率与后果提出风险指数概念,对各事故风险排序;以平均风险指数为尺度筛选出重大事故。采用该方法对某化工项目环境风险评价中重大事故进行了筛选,此方法与修正前的方法计算的结果一致。方法简单易行,为定量确定单个项目中泄漏类重大事故提供了依据。     

Toxicological effects of N,N,N′,N′-tetramethylethylenediamine on electric eel (Electrophorus electricus) acetylcholinesterase and human serum butyrylcholinesterase

This study examined the adverse effects of N,N,N′,N′-tetramethylethylenediamine (TEMED) on electric eel (Electrophorus electricus) acetylcholinesterase (AChE) and human serum butyrylcholinesterase (BChE). Data show that TEMED inhibited AChE in electric eel as well as human serum BChE. Kinetic studies indicated that the inhibition produced by TEMED in both sources was of mixed type, i.e. K_m increased and V _max decreased in a concentration-dependent manner. K_I (constant of ChE–substrate–TEMED complex into ChE–substrate complex and TEMED) was estimated to be 0.674 mM for electric eel and 0.024 mM for human serum BChE. The γK_m (dissociation constant of ChE–substrate–TEMED complex into ChE–TEMED complex and substrate) was 0.083 and 0.2 mM for electric eel AChE and human serum BChE, respectively. The IC₅₀ for electric eel and for human serum ChE was 1.57 and 0.043 mM, respectively. The present results suggest that TEMED produced adverse effects on electric eel and human serum via inhibition of ChE.     

Human serum paraoxonase gene polymorphisms and association with chronic symptoms of pesticide toxicity in Indian farmers

The association between PON1 (serum paraoxonase) genotype and symptoms of pesticide toxicity was examined in a total of 268 farm workers in Andhra Pradesh, India. Approximately 140 of the farm workers who did not report at least two of the symptoms of chronic toxicity, such as abdominal pain, nausea, dizziness, headache, drowsiness, fatigue, tremors of fingers, numbness, or limb weakness were categorized as controls. The remaining 128 farmers showed 2 or more of the above symptoms. All the farm workers were genotyped for polymorphisms of PON1 gene at amino acid positions 55 (exon 3) and 192 (exon 6). A decrease in the percentage of high-activity genotypes at both L55M and Q192R was observed in the farm workers reporting symptoms of pesticide toxicity. When combined genotype distribution at both exons was analyzed, a marked increase in the percentage of low-activity genotypes LLQQ, LMQQ, MMQQ, and MMQR was also observed in symptomatic farmers compared to controls. Age, working years, smoking, duration of exposure, and alcoholism were not statistically significant when compared to symptoms of chronic toxicity. Our findings suggest that L55M and Q192R gene polymorphisms influence the variable susceptibility of farmers to pesticide; and thus may be considered a useful biomarker of genetic susceptibility in assessing an individual's risk of pesticide exposures.     

Effect of dietary Jatropha curcas seed meal on rabbits infested by adult ticks of Hyalomma marginatum marginatum

The objective of this study was to investigate the effectiveness of the oral administration of Jatropha curcas seed meal (JCSM) on serum biochemical parameters and histopathology of skin, liver, and kidney of rabbits experimentally infested by Hyalomma marginatum marginatum. Thirty healthy mixed-breed rabbits were randomly divided into five equal groups. The first group was kept as a control and fed soya bean meal. The remaining groups were fed diets containing 2.5%, 5%, 7.5%, or 10% JCSM. At the sixth week, each group was divided into two subgroups. Ticks were introduced to all members of one subgroup, the other subgroup being kept as control. Blood samples were collected and analyzed for biochemical parameters before (zero time) and after the treatment, on the 6th and 8th weeks. Histopathological studies were conducted 8 weeks after the treatment. The results revealed that JCSM could be used in the treatment of ectoparasites at levels of less than 10% in the diet without any serious effects on liver and kidney functions.     

Strontium and its relationship with trace elements Mg,Cu, Co,and Mo in human blood and serum

The aim of the study was to assess the influence of exposure to strontium on human blood and serum concentrations of magnesium, copper, cobalt, and molybdenum. Inductively coupled plasma–mass spectrometry (ICP-MS) was used to analyze the elemental content of whole blood and blood serum of 97 healthy men including 70 workers in a thermal power plant and 27 control subjects from the rural area of Dragash (Kosovo), an environment without pollution. The results showed that chronic moderate exposure to strontium decreases the levels of copper in blood (BCu) and serum (SCu), of cobalt in blood (BCo) and serum (SCo), and of molybdenum in blood (BMo). All changes in blood and serum concentrations of these essential elements were significant but remained within the normal range. The results suggest that strontium may induce adverse health effects in humans.     

Clinical and analytical follow‐up of 25 persons exposed accidentally to beryllium†

An accidental exposition of 25 persons to beryllium dust was used to follow up trace analytical and clinical parameters over a period of 10 months. Although no exposed person shows any symptoms of an acute beryllium intoxication, up to 5‐fold increased beryllium concentrations could be analysed in serum samples about 10 hours after exposition. The beryllium clearance shows a biological half time in the range of 2 to 8 weeks. The beryllium determination in the nanogram range was carried out using a combined method by flameless a.a.s. with a detection limit of 0.6 ppb Be and a relative standard deviation from 20 to 4% in relation to the concentration range of beryllium measurement.

Beryllium analyses are completed by thorax X‐ray, spirometry, y‐globulins and liver enzymes (SGOT, SGPT), which have shown no pathological values. Because it is known for beryllium to sensitize the cellular immune response, neopterin measurement was used to determine the activity of the immune system. Neopterin, a pteridine synthesized by activated macrophages after stimulation by gamma‐interferon derived from sensitized T‐lymphocytes, was determined in urine samples by HPLC combined with an fluorescence detector. Only in two cases a slight increase of neopterin has been found. As a result of this study it can be summarized, that a short‐time exposure to beryllium (10–20 h), which results in a increase of beryllium in serum to the fivefold normal beryllium level, does not initiate any symptoms of an acute beryllium intoxication. The exposed persons are controlled in future to evaluate the further course.     

Ecotoxicological testing of soil by four bacterial biotests

The objective of this work was threefold. Firstly, this paper intends to introduce four microbial toxicity screening methods (Bacillus subtilis agar diffusion method, Azotobacter agile and Pseudomonas fluorescens dehydrogenase enzyme inhibition tube test, and Photobacterium phosphoreum contact toxicity test) for the investigation of contaminated solid samples such as soil and sediment. Secondly, this work was carried out to prove that both soil characteristics and chemical form of contaminants influence the bioavailability of contaminants and alter the toxicity of soil sample considerably. Thirdly, the sensitivity of the above mentioned four biotests to different contaminants of the soil (heavy metals, organic compounds) was determined and compared. The data evaluation was processed by computer aided statistical methods such as cluster, correlation and principal components analysis by the use of Statgraphics^R.

According to cluster analysis carried out separately for chemical data and biological data, we observed that those samples that have similar chemical composition do not show similar toxicity, which is probably due to different bioavailability of contaminants, the impacts of soil characteristics as well as interaction of contaminants. According to the investigation of sensitivity of the examined four biotests the following conclusion could be drawn: P. phosphoreum and A. agile tests are similar in the sense that they are sensitive to Cu to a large extent and also to PAHs and hydrocarbons (CH) to a lesser extent. B. subtilis test corresponds well with P. fluorescens test method since both tests give good correlation with heavy metals. Neither B. subtilis nor P.fluorescens biotests are sensitive to organic soil contaminants such as PAH and CH.