双酚A(BPA)暴露对WHHL家兔糖类和脂类代谢的影响

为利用和人类更为接近的动物模型来研究在高脂血症条件下,BPA暴露是否能促进脂类和糖类代谢异常,并探索潜在的毒性效应机制,选取渡边可遗传高脂血症家兔(WHHL)模型,通过灌胃的方式将其暴露于400μg·kg-1体重的BPA溶液长达12周。在持续暴露第8周,检测了在空腹状态下,家兔血浆中葡萄糖、胰岛素和脂肪含量的变化,并根据所得结果进行了静脉注射胰岛素耐受试验(IVTT)。在暴露第12周,同样对空腹状态下,家兔血浆中的葡萄糖,胰岛素和脂肪含量进行了检测,并测量了血压和心率。然后,将所有的家兔进行解剖,通过苏木精-伊红(HE)及糖原(PAS)染色分别对心脏和肝脏部位的脂肪及糖原蓄积情况进行了病理学切片分析。同时,检测了肝脏中与脂类和糖类代谢相关基因在m RNA水平上的表达变化。结果显示,BPA暴露8周后促使WHHL家兔发生了胰岛素抵抗现象,导致第12周血糖及胰岛素含量升高,同时也促进了高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)及游离脂肪酸(NEFA)含量的上升。BPA暴露第12周,暴露组WHHL家兔的冠状动脉粥样硬化损伤程度未发生明显增加,但心肌细胞发生了肿胀,胞质中出现了脂肪的蓄积,同时伴随着心律失常。肝脏重量发生增加,肝细胞中同时出现了脂肪和糖原的蓄积现象,相关基因的表达发生了显著上调。研究结果表明,BPA持续暴露可促进WHHL家兔发生脂类和糖类代谢异常,其毒性效应机制可能和胰岛素抵抗及相关基因的异常表达有关。     

畜禽养殖过程抗生素使用与耐药病原菌及其抗性基因赋存的研究进展

兽用抗生素在提高畜禽生产性能、防治疾病方面发挥着重要作用,目前全球超过一半以上抗生素用于畜禽养殖,畜禽养殖源耐药病原菌、抗性基因及其传播风险愈益得到人们的重视。我国是畜禽养殖和抗生素使用大国,但兽用抗生素使用、病原菌耐药水平及其抗性基因类型等数据却较为缺乏,不利于今后畜禽养殖源耐药病原菌及其传播风险的控制。因此,本文通过文献调研,对我国和主要发达国家的兽用抗生素使用情况、畜禽养殖源耐药病原菌及其携带的抗性基因、基因移动元件以及向环境传播的途径进行分析、总结,以期为规范合理用药、降低耐药病原菌及其抗性基因传播风险,建立从畜禽养殖场至公共环境全过程的抗性污染控制链条提供借鉴。     

Characterization and catabolic genes detection of three oil-degrading Rhodococcus spp.北大核心CSCD

Oil pollution is one of the major factors causing environmental deterioration. Bioremediation of oil contaminated environments by microorganisms attracts much research attention. This study aimed to screen efficient oil-degrading bacteria from oil contaminated soil and analyze their characteristics and catabolic genes. Oil-degrading bacteria were screened from oil contaminated soil in minimal medium containing crude oil and identified by morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis. Their growth and degradation characteristics were studied with ultraviolet spectroscopy and GC-MS analysis. The surfactant production was studied by adopting culture method. The major oil-degrading related genes were detected by t he PCR a mplification. As a result, t hree oil-degrading bacteria strains named KB1, 2182 and JC3-47 were isolated from the oil contaminated soil samples. The strains could use crude oil as the sole carbon source to degrade oil with a degrading rate of 41.02%, 32.26% and 55.90%, respectively, when cultured in minimal medium containing crude oil for 3 days. The bacteria were identified to belong to genus Rhodococcus. With 100% similarity of 16S rDNA sequences of the three strains with known ones of Rhodococcus, KB1 was preliminarily identified as Rhodococcus erythropolis, 2182 as Rhodococcus equi, and JC3-47 as Rhodococcus qingshengii. They grew well at 10-50 °C, with the initial pH of 3-9 and the NaCl concentration of 0-5%. The optimal temperature for bacterial growth was 35 °C, 35 °C and 30 °C respectively. KB1 and 2182 could grow at pH 2 and 9.0% of NaCl. The bacteria grew well in broth containing different organic substrates as sole carbon source, such as n-dodecane, n-octadecane, benzene, methylbenzene, xylene and naphthaline. KB1 and JC3-47 could grow well in broth containing pyrene. GC-MS analysis revealed that the bacteria could effectively degrade medium- and long-chain alkane components in crude oil. The bacteria produced biosurfactants and decreased the surface tension of the culture broth. They also showed adhesion activities to n-hexadecane. The oil-degrading related genes such as alkane monooxygenase, aromatic-ring-hydroxylating dioxygenase and catechol dioxygenase genes were detected in all the three strains. Besides, biphenyl dioxygenase genes were detected in KB1 and 2182. The isolated Rhodococcus spp. strains could effectively degrade petroleum hydrocarbons with high adaptabilities to extreme environments such as high salt and low temperature. They are supposed to be applied broadly in the bioremediation of oil contaminated soil in such environments.     

多溴联苯醚微生物降解过程与机理的研究进展

多溴联苯醚(PBDEs)属溴代阻燃剂,曾因其优良的阻燃性能而广泛应用于电子电器、石油化工和建材纺织等工业产品中.然而,随着大量生产和使用,PBDEs已成为大气、水体、土壤和生物体等多环境介质中普遍检出且极具生态风险的有机污染物.因此,开展微生物降解研究对于典型环境中PBDEs污染风险消除和污染修复,具有重要的科学意义.本文从PBDEs环境归趋行为及其暴露风险出发,综述了PBDEs微生物厌氧降解和好氧降解的最新研究动态,比较分析了两种降解过程的降解特性与影响因素,并针对微生物,尤其是好氧微生物降解机理,阐述了bph A或etb A功能基因及其编码酶对PBDEs好氧降解过程的调控作用,同时就PBDEs微生物高效降解菌种选育、降解机理等方面的研究趋势进行了展望.     

长期施用猪粪水稻土抗生素抗性基因污染研究

为了全面研究猪粪有机肥对水稻土抗生素抗性及分布格局的影响,选择295对抗生素抗性基因引物,采用高通量荧光定量PCR对水稻土中的抗生素抗性基因污染情况进行了研究.结果表明,未施用猪粪水稻土检测出66种抗性基因,而施用猪粪水稻土则检测出107种抗生素抗性基因,施用猪粪后水稻土中抗生素抗性基因种类显著增加(P<0.05).相对于未施用猪粪水稻土,施用猪粪水稻土有49种抗生素抗性基因丰度显著增加(P<0.05),其中施用猪粪水稻土中喹诺酮类/氯霉素类抗性基因的mexF的丰度相对于未施用猪粪水稻土增加1791倍.高通量定量结果表明,施用猪粪的水稻土抗生素抗性基因分布格局发生显著变化,高通量定量技术是研究环境抗生素抗性基因的一个非常实用的工具.     

The exposure risks associated with pathogens and antibiotic resistance genes in bioaerosol from municipal landfill and surrounding area

Pathogenic microbes with antibiotic resistance can thrive on municipal solid waste as nutrients and be aerosolized and transported to vicinities during waste disposal processes. However, the characterization of pathogenic bioaerosols and assessment of their exposure risks are lacking. Herein, particle size, concentration, activity, antibiotic resistance, and pathogenicity of airborne microorganisms were assessed in different sectors of a typical landfill. Results showed that active sector in downwind direction has the highest bioaerosol level (1234 CFU/m³), while residential area has the highest activity (14.82 mg/L). Botanical deodorizer from mist cannon can effectively remove bioaerosol. Most bioaerosols can be inhaled into respiratory system till bronchi with sizes ranging from 2.1−3.3 and 3.3−4.7 µm. Pathogenic bacteria (Bacilli, Bacillus, and Burkholderia-Paraburkholderia) and allergenic fungi (Aspergillus, Cladosporium, and Curvularia) prevailed in landfill. Although high abundance of microbial volatile organic compounds (mVOCs) producing bioaerosols were detected, these mVOCs contributed little to odor issues in landfill. Notably, surrounding areas have higher levels of antibiotic-resistance genes (ARGs) than inner landfill with tetC, acrB, acrF, mdtF, and bacA as dominant ones. Most ARGs were significantly correlated with bacterial community, while environmental parameters mainly influenced fungal prevalence. These findings can assist in reducing and preventing respiratory allergy or infection risks in occupational environments relating to waste management.     

灾害地貌专家系统试验研究

介绍了灾害地貌专家的建造原理与方法,阐述了灾害地貌专家知识的分类分级方法,讨论了灾害地貌专家系统中知识表示的基本原则和知识库中专家知识的组织方式,以及推理机的设计和推理规则的构造原理与方法。系统采用压缩编码方式存储各种地学专题图形和遥感图像数据,具有与图像的存储更新,查询检索、分析处理、图像显少自动制图功能。该系统可以对灾害地貌过程进行专家级的预测和评价,并对灾害地貌的综合治理与区域规划提出几种可     

多源土地利用地学知识的获取与应用

土地利用地学知识可应用于LIS智能化分析及辅助遥感影像解译,是国土信息化工程建设中值得深入研究的重要技术环节之一.明确了土地利用地学知识概念,构建了多数据源的土地利用地学知识体系,针对不同数据源分析了土地利用地学知识的获取及表达,并着重对土地利用地学知识辅助遥感影像解译进行了阐述,指出采用知识辅助高分辨率遥感影像解译是亟待深入开展研究的课题.     

分光光度法分析中增色、褪色反应标准曲线绘制的一般形式

介绍了在分光光度法分析中，增色反应和褪色反应的标准曲线绘制用朗伯-比耳定律可推导出一般数学表达形式。其中增色反应为Ai=kbCi，使用频率较高；褪色反应为A0-Ai=k′bCi，实际工作中应用较少。     

真鲷去毒相关基因cDNA序列的克隆与肝脏组成型表达分析

赤潮发生时产生的一些海洋生物毒素对人类和海洋动物的安全形成潜在的威胁甚至导致死亡.为从分子水平探讨鱼类中海洋藻毒素的去毒分子机理,采用RT-PCR法克隆了真鲷(Pagrus major)肝脏芳香烃受体核转位蛋白(ARNT)和I时相异生素代谢酶细胞色素P4501A(CYP1A)基因cDNA核心序列,同时,应用半定量RT-PCR方法,以β-肌动蛋白作为外参照,在其指数期增长的范围内研究了芳香烃受体(AHR)、ARNT、CYP1A、II时相异生素代谢酶alpha型谷胱甘肽S-转移酶(GSTA1、GSTA2)、rho型谷胱甘肽S-转移酶(GSTR)、热休克蛋白70(HSP70)基因组成型表达水平.结果发现,真鲷ARNT、CYP1A基因cDNA核心序列片段分别长438bp和908bp,分别编码146和302个氨基酸.序列同源性分析发现,真鲷与门齿鲷(Stenotomus chrysops)、石首鱼(Micropogon undulatus)ARNT基因氨基酸序列同源性高达97.2%、95.2%,与斑马鱼(Brachydanio rerio)、人、大鼠、小鼠ARNT同源性较低(77.2%～79.3%).真鲷与门齿鲷、金头鲷(Sparus auratus)、欧洲川鲽(Rhombus maximus)、欧洲海鲈(Dicentrachus labrax)CYP1A基因氨基酸序列同源性较高,为84.8%～94.0%,与斑马鱼、人、小鼠CYP1A同源性较低,为59.6%～77.8%.真鲷肝脏AHR、ARNT、CYP1A、GSTA1、GSTA2、GSTR和HSP70基因组成型表达水平分别为(25.32±6.56)%、(26.22±4.24)%、(146.5±16.06)%、(55.42±3.75)%、(48.82±10.89)%、(79.47±3.13)%、(107.42±14.34)%.