宁波滩涂贝类养殖区沉积物中有机氯农药和多氯联苯残留及生态风险评估

利用GC-ECD对宁波市主要滩涂贝类养殖区表层沉积物中的多氯联苯(PCBs)和有机氯农药六六六(HCHs)、滴滴涕(DDTs)的残留量进行测定,研究其分布状况,并进行生态风险评估.结果表明:贝类养殖区表层沉积物中的总有机氯农药含量为0.80～32.40ng·g-1,多氯联苯含量为3.20～33.33 ng·g-1.HCHs主要来自远距离大气传输及历史残留,部分区域有DDTs输入,其来源可能是三氯杀螨醇的使用.大部分站位的p,p’-DDT和DDTs存在潜在的生态风险,其中墙头和西店海域的p,p’-DDT残留超过生物效应中值,对底栖生物毒害效应较高.大多数站位PCBs的生态风险较低.     

土壤和沉积物中多氯代有机化合物厌氧降解研究进展

多氯代有机化合物(PCOCs)是土壤和沉积物中的典型污染物,厌氧条件下PCOCs能够发生脱氯发应,从而使其毒性大大降低,脱氯后形成的低氯代化合物可以进一步好氧降解,直至完全矿化。从PCOCs的降解过程出发,重点综述了几种典型PCOCs的厌氧脱氯机理以及几种重要影响因素;阐明了脱氯反应是PCOCs厌氧降解的关键步骤,反应的发生必须有还原剂提供电子,微生物的参与尤为重要;同时展望了同位素示踪法在研究PCOCs降解机制上的应用,以及开发高效降解PCOCs微生物的必要性等。     

外源乙烯对长春花生理水平和生物碱积累的影响

药用植物长春花中含有100多种萜类吲哚生物碱（TIAs）,其中具有抗肿瘤功效的长春碱和长春新碱受到关注。为了研究外源乙烯处理对长春花生长情况、生理状态和萜类吲哚生物碱合成的整体影响,本文以长春花幼苗为实验材料,使用外源乙烯处理后对比了不同生长条件下长春花的生物量积累、根茎伸长、光合参数以及生物碱含量等指标,分析了生物碱合成与其他指标之间的相关性。结果表明,外源乙烯处理使长春花乙稀释放量上升,乙烯信号响应因子erf基因表达量提高。乙烯利抑制长春花幼苗生物量积累、根纵向生长,促进茎秆横向加粗生长,由非气孔因素导致净光合速率（P_n）和气孔导度（G_s）下降。外源乙烯促进异胡豆苷（STR）、长春质碱（CAT）、文多灵（VIN）和长春碱（VINB）积累,并且促进长春碱合成途径中关键酶基因str和CrPRX上调表达。相关性分析结果表明,次生代谢产物的积累、生长指标、光合参数之间存在明显的相关性;长春质碱、文多灵、长春碱与茎秆直径（SD）显著正相关（P < 0.05）,与生物量（B）、株高（H）、根长（RL）、净光合速率（P_n）呈显著负相关（P < 0.05）。本文为研究外源乙烯调控长春花生物碱积累的机制提供理论基础。     

不同氮水平下盐胁迫对大麦幼苗中某些氮化物积累的影响(简报)

在土培条件下,提高氮素供应水平和NaCl处理浓度后大麦幼苗地上部和根中的全氮,蛋白质氮和游离氨基酸总量增加;蛋白质氮占全氮的比值亦因NaCl处理浓度的增大而提高。在盐胁迫下,游离脯氨酸占氨基酸总量的百分比明显增加,而谷氨酸所占比例则下降。     

水稻籽粒发育过程中各器官镉积累量的变化及其与基因型和土壤镉水平的关系

以镉（Cd）积累潜力不同的2个籼稻品种为材料,研究了籽粒发育过程中各器官中Cd含量的动态变化及其与土壤中Cd含量的关系。结果表明,在含Cd的生长环境中,水稻根系中的Cd含量在整个生育期中保持稳定增长的趋势,而茎叶、穗轴和稻壳等器官在营养生长阶段积累了大量的Cd,然后在籽粒充实过程中向外输出,其中旗叶和稻壳中的Cd输出率在50%以上,明显高于其他营养器官。根系和叶片中的Cd含量与土壤中的Cd含量呈高度线性相关,茎秆和籽粒中的Cd含量与土壤中的Cd含量呈抛物线相关,说明根系、茎秆、叶片等营养器官对Cd有储存和“过滤”作用。低积累品种‘X24’穗轴中的Cd含量明显低于高积累品种‘T705’,说明营养器官中的Cd向籽粒中转运的速率是决定籽粒中Cd积累量的关键因素。但是,只有当土壤中的Cd含量为0.3~1.2 mg＆#183;kg-1时,低积累品种精米中的Cd含量才会显著低于高积累品种;当土壤中的Cd含量高于2.4 mg＆#183;kg-1时,2个品种精米中的Cd含量没有显著差异。     

北京主要绿化植物和土壤对大气中硫的积累特点及其指示、净化作用

本文研究了北京城、近郊区50种植物和土壤对硫的吸收、积累特点及其指示、净化作用。结果表明:不同植物种以旱柳的含硫量最高,珍珠梅的含硫量最低;不同类型植物的含硫量以苔藓植物>阔叶落叶乔木>草本植物>落叶灌木>常绿针叶乔木;植物、土壤的含硫量都以工业污染区最高,植物含硫量可为自然背景值的2.5—10倍,土壤含硫量可为自然背景值的4倍。主要绿化植物和土壤的含硫量可指示出不同功能区硫的污染状况,反应本区大气的环境质量。研究的10种植物的吸收净化量,乔木中以泡桐最大,约6kg/ha·a,依次为泡桐>旱柳>槐树>刺槐>毛白杨;灌木以紫丁香最大,约达4kg/ha·a,依次为紫丁香>珍珠梅>榆叶梅>紫薇>连翘。上述研究结果,可为城市规划和选择适宜的,净化量大、抗性强的绿化树种提供科学依据。     

Cd-Cu复合胁迫对黄菖蒲叶片及根系中Cd和Cu的积累及其迁移率的影响

采用水培法研究了Cd-Cu复合胁迫(5 mg·L-1Cd-10 mg·L-1Cu;5 mg-L-1Cd-20 mg·L-1Cu;25 mg·L-1 Cd-10 mg·L-1Cu;25 mg·L-1Cd-20 mg·L-1Cu)条件下黄菖蒲(Iris pseudacorus L.)叶片和根系对Cd和Cu的积累作用及黄菖蒲体内Cd和Cu迁移率的变化规律.结果表明,在50 d的胁迫期内,黄菖蒲叶片和根系中的Cd和Cu含量分别随培养液中Cd和Cu浓度的提高而增加,并随胁迫处理时间的延长基本呈增加的趋势,在胁迫末期明显提高.在不同浓度Cd-Cu复合胁迫条件下,黄菖蒲根系中的Cd和Cu积累量明显高于叶片.在Cd浓度不变的条件下,黄菖蒲叶片和根系中的Cd含量随培养液中Cu浓度的提高而增加;在Cu浓度不变的条件下,黄菖蒲叶片中Cu含量随培养液中Cd浓度的提高而降低.在不同胁迫时间,黄菖蒲植株对Cd的迁移率不同,但培养液中Cd的浓度较高,黄菖蒲植株对Cd的迁移率也较高;黄菖蒲植株对Cu的迁移率随胁迫时间的延长基本上呈上升趋势.研究结果显示,在Cd-Cu复合胁迫条件下,Cu对黄菖蒲体内Cd的吸收具有一定的协同吸收作用,而Cd对Cu的吸收则有一定的拈抗作用.     

二化性家蚕滞育、非滞育和即时浸酸卵中糖代谢相关酶mRNA水平和活性的变化

【目的】探究家蚕Bombyx mori胚胎发育早期卵内糖代谢与滞育的关系。【方法】以家蚕二化性品种“秋丰”活化越年卵为材料,一部分于17℃暗催青,孵化后常规饲养,制备非滞育命运卵(ND);另一部分于25℃明催青,孵化后常规饲养,制备滞育命运卵(DD),再用盐酸溶液处理部分DD卵制备即时浸酸卵(IA)。在卵产下或浸酸后0, 2, 6, 12, 24, 48, 72和96 h分别取样,利用qRT-PCR测定家蚕卵中己糖激酶(hexokinase, HK)、磷酸果糖激酶(phosphofructokinase, PFK)、山梨醇脱氢酶(sorbitol dehydrogenase, SDH)、磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate carboxykinase, PEPCK)和海藻糖酶(trehalase, TRE)5种糖代谢相关酶基因的mRNA表达水平,利用紫外-可见分光光度法测定家蚕卵中这5种酶的活性。【结果】家蚕糖酵解途径关键酶己糖激酶(BmHK)和磷酸果糖激酶(BmPFK),以及糖分解代谢关键酶山梨醇脱氢酶(BmSDH-1)和海藻糖酶(BmTRE)在ND和IA中的mRNA水平和活性均普遍高于在DD中的;而糖异生途径相关的磷酸烯醇式丙酮酸羧激酶(BmPEPCK)在DD中的mRNA水平和活性均高于在ND和IA中的。【结论】结果提示,DD因胚胎滞育的需要,胚胎发育早期卵内糖代谢以能量和物质的贮存为主;而ND和IA由于胚胎发育进程较快,糖代谢以物质分解代谢为主。本研究初步揭示了家蚕卵内糖代谢与滞育的关系,有助于更好地理解家蚕滞育的分子机制。     

Persistente chlororganische Verbindungen, Quecksilber und radioaktive Nuklide in Eiern von Rotmilanen (Milvus milvus) aus Sachsen-Anhalt

Zusammenfassung  Insgesamt wurden 60 Resteier des Rotmilans in drei Untersuchungsgebieten im südlichen Teil des Bundeslandes Sachsen-Anhalt zwischen 1987–1993 gesammelt und auf elf persistente Chlorkohlenwasserstoff-Verbindungen und Quecksilber sowie z. T. auf radioaktive Nuklide untersucht:

On the inhibition of microsomal drug metabolism by polychlorinated biphenyls (PCB) and related phenolic compounds.

The in vitro metabolism of p-nitroanisole, aminopyrine, and aniline by rat liver microsomal monoxygenases were studied in the presence of different polychlorinated biphenyl (PCB) mixtures and some related hydroxybiphenyls. The tested PCB mixtures contained preferably dichloro- (di-CB), tetrachloro- (tetra-CB), or hexachlorobiphenyls (hexa-CB). All PCB were competitive inhibitors of only aminopyrine demethylation by normal microsomes (Ki 22-39 micron). In microsomes of PCB-pretreated rats the aminopyrine demethylation was inhibited noncompetitively by di-CB and hexa-CB whereas tetra-CB remained a competitive inhibitor (Ki 12 micron). Moreover, after PCB pretreatment all PCB were competitive inhibitors of p-nitroanisole demethylation. 2-OH-biphenyl and 4-OH-biphenyl caused competitive inhibition of aminopyrine demethylation and aniline hydroxylation but failed to inhibit p-nitroanisole metabolism by normal microsomes. Chlorinated 4-hydroxybiphenyls inhibited competitively the metabolism of both type I and type II substrates. However, after PCB pretreatment all phenolic compounds caused uncompetitive inhibition of aniline hydroxylation.     

New high-resolution mass spectrometric approach for the measurement of polychlorinated biphenyls and organochlorine pesticides in human serum

To increase our analytical throughput for measuring polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides without sacrificing data quality, we have developed and validated a combined PCB/OC pesticide gas chromatography-high-resolution mass spectrometry (GC-HRMS) analysis. In a single GC-HRMS analysis, both selected PCBs and OC pesticides are detected and quantified. Previously, this has been difficult, if not impossible, because of the major difference in masses of the most abundant electron-impact ions. However, we have identified slightly less abundant ions to monitor that allow us to successfully combine these analytes into a single analysis without sacrificing any analytical sensitivity or instrument reliability. Consequently, we have been able to double our analytical throughput by modification of mass spectrometric parameters alone. Our new methodology has been validated against our current GC-HRMS method, which entails using two separate injections, one for PCB analysis and one for OC pesticide analysis. The two methods differ by less than 4% overall, with no systematic bias. We used this method to analyze approximately 350 serum samples over a period of several months. We found that our new method was as reliable in automated, overnight runs as our current method.     

Improved sample preparation method for selected persistent organochlorine pollutants in human serum using solid-phase disk extraction with gas chromatographic analysis

An improved solid-phase extraction (SPE) method was developed to isolate and concentrate trace levels of selected POPs (persistent organochlorine pollutants) in human serum prior to GC–MS in SIM mode or GC–ECD quantitation. The extraction involves denaturation of serum proteins with formic acid, SPE using C₁₈ Empore™ disk cartridges, followed by elimination of lipid interferences using a sulfuric acid wash of the eluate. Use of the SPE disk improved assay throughput and gave a cleaner analytical matrix compared with previously reported solid-phase and liquid–liquid extraction techniques. The extraction method provided consistent recoveries at three fortification levels using ¹³C₁₂ PCB 149 as internal standard. Recoveries ranged from 48 to 140% for organochlorine pesticides (6.25, 12.5 and 25 ng/ml) and 71 to 126% for polychlorinated biphenyls (0.625, 1.25 and 2.5 ng/ml).     

The reductive dechlorination of 2,3,4,5-tetrachlorobiphenyl in three different sediment cultures: evidence for the involvement of phylogenetically similar Dehalococcoides-like bacterial populations

Anaerobic cultures capable of reductively dechlorinating 2,3,4,5-tetrachlorobiphenyl (CB) were enriched from three different sediments, one estuarine, one marine and one riverine. Two different electron donors were used in enrichments with the estuarine sediment (elemental iron or a mixture of fatty acids). The removal of doubly flanked meta and para chlorines to form 2,3,5-CB and 2,4,5-CB was observed in all cultures. Bacterial community analysis of PCR-amplified 16S rRNA gene fragments revealed different communities in these cultures, with the exception of one common population that showed a high phylogentic relatedness to Dehalococcoides species. No Dehalococcoides-like populations were ever detected in control cultures to which no PCBs were added. In addition, the dynamics of this Dehalococcoides-like population were strongly correlated with dechlorination. Subcultures of the estuarine sediment culture demonstrated that the Dehalococcoides-like population disappeared when dechlorination was inhibited with 2-bromoethanesulfonate or when 2,3,4,5-CB had been consumed. These results provide evidence that Dehalococcoides-like populations were involved in the removal of doubly flanked chlorines from 2,3,4,5-CB. Furthermore, the successful enrichment of these populations from geographically distant and geochemically distinct environments indicates the widespread presence of these PCB-dechlorinating, Dehalococcoides-like organisms.     

微生物降解多氯联苯的研究进展

多氯联苯是一种持续性有机污染物,在自然环境中很难降解。在目前研究的降解方法中,微生物降解最具潜力。本文对多氯联苯微生物降解的研究进展进行了综述,包括厌氧还原脱氯,好氧氧化以及生物表面活性剂的作用,介绍了几种降解方法耦合应用的现状和前景,指出了应用中存在的问题和今后的发展方向。