敌百虫、多菌灵对蚯蚓的自然土壤法毒性实验

在采用滤纸接触法研究的基础上,本试验采用自然土壤法研究了敌百虫、多菌灵对蚯蚓的毒性效应,结果显示,敌百虫对蚯蚓的LC50为4.332 g·L-1,多菌灵对蚯蚓的LC50为5.3645 g·L-1.自然土壤法中敌百虫对蚯蚓的毒性比多菌灵对蚯蚓的毒性大.     

PFOS对蚯蚓急性毒性和回避行为的影响

全氟辛烷磺酰基化合物(PFOS)作为一种新型持久性有机污染物,已经成为环境科学和毒理学的研究热点,其对生态环境的影响值得深入研究.本文采用OECD标准滤纸接触法、人工土壤法及自然土壤法研究了PFOS对蚯蚓急性致死作用及回避行为的影响.结果表明： PFOS对蚯蚓的急性毒性作用与染毒时间和染毒浓度相关,试验求得滤纸法48 h、人工土壤法14 d和自然土壤法14 d的LC₅₀值分别为13.64 μg·cm^-2、955.28 mg·kg^-1和542.08 mg·kg^-1;人工土壤和自然土壤中蚯蚓在PFOS的最大试验浓度组160 mg·kg^-1中均表现出显著的回避行为,表明蚯蚓可以明显感知较高浓度PFOS污染土壤并作出回避反应.与急性毒性试验的测试终点LC₅₀相比,蚯蚓行为测试终点对PFOS的反应更为敏感.自然土壤中PFOS对蚯蚓的急性毒性大于人工土壤,相同浓度PFOS作用下,蚯蚓于自然土壤中的回避行为较人工土壤明显.     

多菌灵和敌百虫单一与复合污染对蚯蚓的毒性效应研究

采用滤纸接触法研究了赤峰市周边地区普遍使用的农药多菌灵和敌百虫单一与复合污染对蚯蚓毒性效应.单一试验结果表明蚯蚓在这两种农药作用下表现出不同的中毒症状和死亡情况,敌百虫的毒性大于多菌灵的毒性,48 h时多菌灵和敌百虫的LC50分别为1.2795 g·L-1和0.0511 g·L-1;复合试验结果表明,多菌灵与敌百虫混合后毒性减弱,即二者复合作用表现为拮抗作用.     

几种杀虫剂对嗜虫书虱的触杀作用

采用滤纸药膜法比较了常用8种杀虫剂对嗜虫书虱Liposcelis entomophila的触杀作用,在药剂的推荐浓度下有机磷类杀虫剂对嗜虫书虱的急性触杀作用强于其它药剂.同时测定了杀螟硫磷、敌敌畏和溴氰菊酯(含增效醚)3种药剂对嗜虫书虱的触杀毒力,其24h内触杀作用的LC50分别为9.3284、2.1440和7.5007 μg/cm2,但杀螟硫磷的LC95为459.4949 μg/cm2,远高于敌敌畏的8.2453μg/cm2和溴氰菊酯(含增效醚)的14.5274 μg/cm2.此外,48h内敌敌畏等有机磷杀虫剂对嗜虫书虱的毒杀速度较其它供试药剂快.     

八种杀虫剂对愈纹萤叶甲成虫的毒力及田间防控效果

【目的】为探索适用于愈纹萤叶甲Galeruca reichardti成虫的防治药剂室内毒力测定方法,并筛选其防治的有效药剂。【方法】分别采用浸虫法、浸叶法和胃毒触杀联合毒力法测定了8种药剂对其成虫的毒力,并通过大田试验进一步验证。【结果】浸虫法测得除虫菊素对愈纹萤叶甲成虫的毒力最高,其LC50值为68.24 mg/L;浸叶法测得氟啶虫胺腈的毒力最高,其LC50值为111.11 mg/L;胃毒触杀联合法测得氟啶虫胺腈的毒力最高,其LC50值为67.94 mg/L。其中,除虫菊素毒力值变化最大,浸虫法毒力是浸叶法的28.97倍,胃毒联合法毒力是浸叶法的17.83倍。蛇床子素、苦参碱在3种生测方法中毒力较低。田间试验结果显示,50%氟啶虫胺腈水分散粒剂562.5 g/hm2防治效果达94.90%,对韭菜苗保苗效果为81.45%,且显著高于其他药剂。【结论】3种毒力测定方法均可用于该虫的毒力测定,而从此虫的为害特点来看,胃毒触杀联合毒力法更能显示药剂的毒力性质。在愈纹萤叶甲成虫盛发期选择氟啶虫胺腈喷施可以有效减轻该虫为害。     

龄期、饲养条件及生测方法对韭菜迟眼蕈蚊对药剂敏感性的影响

为建立针对韭蛆的简便、可靠的生测方法，采用胃毒触杀联合毒力法、人工饲料混药法和浸虫法分别测定毒死蜱、噻虫胺对韭蛆不同龄期幼虫的毒力，以明确龄期、温度和饲料等饲养条件及生测方法对韭菜迟眼蕈蚊对药剂敏感性测定结果的影响。三种方法测得2龄幼虫对毒死蜱的敏感性分别为4龄幼虫的11.9倍、7.4倍、3.3倍；4种饲料饲养的试虫，毒死蜱对取食韭菜、人工饲料、大葱的LC50分别为圆葱的1.84倍、1.47倍、2.31倍；在15~30℃范围内，随着试虫的饲养温度的升高，毒死蜱对韭蛆4龄幼虫的LC50不断增大；三种方法测得毒死蜱对4龄幼虫的LC50分别为67.199 mg/L、71.123 mg/L、88.120 mg/L，噻虫胺对4龄幼虫的LC50依次为3.584 mg/L、2.255 mg/L、4.329mg/L，并且胃毒触杀联合毒力法和人工饲料混药法的毒力曲线拟合度要好于浸虫法。试验表明：试虫龄期、饲养温度、饲养饲料等因素对韭菜迟眼蕈蚊对药剂敏感性存在明显影响，采用胃毒触杀联合毒力法和人工饲料混药法测定的结果比浸虫法准确可靠。     

6种重金属对赤子爱胜蚓的急性毒性效应与风险评价

【背景】近年来,土壤重金属污染问题日益凸显,对生态环境、食品安全和人体健康构成了严重威胁,其急性毒性尚未明确。【方法】采用滤纸接触法和人工土壤法测定了铜(Cu2+)、锌(Zn2+)、镍(Ni+)、镉(Cd2+)、铅(Pb2+)和锰(Mn2+)等6种重金属对赤子爱胜蚓的急性毒性效应,并参照欧盟指令91/414/EEC标准评价了其环境风险。【结果】滤纸接触法48h测定结果表明,6种重金属对蚯蚓的LC50为3.17(2.53～3.81)～90.42(69.45～140.47)μg.cm-2,其毒性次序为Cu2+>Zn2+>Ni+>Cd2+>Pb2+>Mn2+。人工土壤法14d测定结果表明,6种重金属对蚯蚓的LC50为1347(1236～1453)～6936(6144～8930)mg.kg-1,其毒性次序为Cu2+>Cd2+>Ni+>Zn2+>Mn2+>Pb2+。风险评价结果显示,Cu2+、Zn2+、Ni+、Cd2+、Pb2+和Mn2+等6种重金属的暴露比(toxicity/exposureratio,TER)分别为3.37、4.46、8.68、1428、13.87和5.85。【结论与意义】6种重金属对土壤动物蚯蚓均具有潜在的毒性效应。Cu2+、Zn2+、Ni+、Mn2+等4种重金属对赤子爱胜蚓存在急性毒性风险,而Cd2+和Pb2+对赤子爱胜蚓的急性毒性风险水平是可接受的。该评价结果可为我国制定基于风险的土壤环境质量标准提供依据。     

阿维菌素B1a对土壤微生物和蚯蚓的影响

研究了不同阿维菌素B_1a浓度对种土壤微生物生长和呼吸强度的影响及对土壤中蚯蚓的急性毒性.结果表明,土壤中阿维菌素B_1a浓度在83.3 mg·kg^-1以上时对种土壤细菌均表现出明显的抑制作用,但对土壤真菌不表现抑制作用.高浓度阿维菌素B_1a对土壤微生物的呼吸强度有抑制作用,并且在不同土壤其作用有差异.采用滤纸接触试验和人工土壤试验测定阿维菌素对蚯蚓的急性毒性(半数致死量,LD₅₀),接触毒性LD₅₀为.63μg·cm^-2,土壤法试验测定的LD₅₀在处理后第7 d和第1 d分别为2.13和17.06 mg·kg^-1.     

水菖蒲超临界CO_2萃取物对德国小蠊的触杀和驱避活性

水菖蒲(Acorus calamus L.)超临界CO2萃取物对德国小蠊Blattella germanica L.同时具有很好的触杀和驱避活性。采用药膜接触法和滤纸药膜选择法,分别研究水菖蒲超临界CO2萃取物对德国小蠊3龄若虫的触杀和驱避活性。结果表明:水菖蒲超临界CO2萃取物对德国小蠊的生物活性存在着明显的浓度-时间-效应。触杀作用中处理试虫12h后,最高浓度124.00μg/cm2的校正死亡率就达到98.33%,24h后达到100%。试虫在处理12h后的LC50为36.45μg/cm2。驱避活性中,最高浓度815.28μg/cm2的驱避率为67.73%,驱避等级达到了Ⅳ级。     

不同饲毒法测定Bt8010毒力效价研究

以棉铃虫初孵幼虫为供试虫,用合成饲料和天然饲料两种饲毒法,CS3ab-1991（毒力效价Ha 15000IU/mg)为标准品对Bt 8010粉剂进行毒力测定,饲毒后的供试虫在30℃恒温下培育72小时,合成饲料饲毒法测定的CS3ab-1991 LC50=108.6±10.8μg/ml,Bt8010 LC50=197.1±15.6μg/ml,毒力效价8273.1±715.8Ha IU/mg,天然饲料饲毒法测定的CS3ab-1991 LC50=406.3±47.5μg/ml,Bt8010 LC50=705.0±86.8μg/ml,毒力效价8633.2±871.8Ha IU/mg。     

Embryo and Endosperm Function and Failure inSolanumSpecies and Hybrids

Although the importance of the endosperm as a food store inmany angiosperm seeds is well known, its significance duringearly embryogenesis has been neglected. In many interspecifichybrids, and in some other situations, embryos do not developfully and abort. It has often been stated that this is causedby the endosperm failing to conduct sufficient nutrients tothe embryo, but seldom has it been suggested that the endospermactively controls most of the early stages of morphogenesisof the embryo. Information gleaned from a broad survey of theliterature, combined with additional evidence presented here,obtained fromSolanum incanumand interspecific hybrids, indicatethat the endosperm is dynamic and very active in regulatingearly embryo development. This requires highly integrated geneticcontrol of rapidly changing metabolism in the endosperm. Ininterspecific hybrids, lack of coordination may cause unbalancedproduction of growth regulating substances by the endospermand hence abortion of the embryo, or even unregulated productionof nucleases and proteases resulting firstly in autolysis ofthe endosperm and then digestion of the embryo. The endospermmay thus serve to detect inappropriate hybridization of speciesor ploidy levels and so prevent waste of resources by producingseeds that would result in sterile hybrids or unthrifty subsequentgenerations. This discriminatory function of the endosperm hasdiminished during evolution and domestication of the crop plantSolanummelongenaL.Copyright 1998 Annals of Botany Company Solanum, embryo morphogenesis, endosperm, hybrid, seed development.     

Pragmatic Women and Body Politics and Maternities and Modernities: Colonial and Postcolonial Experiences in Asia and the Pacific

Pragmatic Women and Body Politics. Margaret Lock and Patricia A. Kaufert. eds. Cambridge, UK: Cambridge University Press, 1998. xii +364 pp.
Maternities and Modernities: Colonial and Postcolonial Experiences in Asia and the Pacific. Kalpana Ram and Margaret Jolly. eds. Cambridge, UK: Cambridge University Press, 1998. xiv. 305 pp.     

HIFs and tumors--causes and consequences

For most organisms oxygen is essential fo life. When oxygen levels drop below those required to maintain the minimum physiological oxygen requirement of an organism or tissue it is termed hypoxia. To counter act possible deleterious effects of such a state, an immediate molecular response is initiated causing adaptation responses aimed at cell survival. This response is mediated by the hypoxia-inducible factor-1 (HIF-1), which is a heterodimer consisting of an alpha- and a beta-subunit. HIF-1 alpha protein is stabilized under hypoxic conditions and therefore confers selectivity to this response. Hypoxia is characteristic of tumors, mainly because of impaired blood supply resulting from abnormal growth. Over the past few years enormous progress has been made in the attempt to understand how the activation of the physiological response to hypoxia influences neoplastic growth. In this review some aspects of HIF-1 pathway activation in tumors and the consequences for pathophysiology and treatment of neoplasia are discussed.     

环腺苷酸应答元件结合蛋白与学习记忆

环腺苷酸(cAMP)应答元件结合蛋白(cAMP response element binding protein,CREB)是一种核转录因子,可与cAMP反应元件结合,调节基因转录,具有调节精子生成,昼夜节律,学习记忆等功能.近年来关于其在学习记忆中的作用成为医学研究热点.CREB是神经元内多条信息传递途径的汇聚点,参与长时记忆形成和突触可塑性.长时记忆(long-term memory)形成需依赖CREB介导的基因转录,干扰或抑制CREB活性可破坏长时记忆.长时程增强(long-term potentiation,LTP)是研究学习记忆的理想模型,在LTP诱导和维持过程中均可观察到CREB活性持续升高.但增龄过程中,海马CREB活性下降,影响学习记忆功能,与许多神经退行性疾病发生有关.     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

Morphological and constitutional features and self-esteem in children and adolescents

Studies of human constitution and mental features are traditionally among the main concepts of anthropological research. In this research, we attempted to discover connections between morphological and constitutional features and self-esteem in children and adolescents. Such a connection was discovered in some studied age groups. The obtained results could serve as a basis for further studies in this field.