长期使用农药的土壤微生态变化研究初探

目的通过PCR-DEEG方法比较长期使用农药的土地和正常的土地菌群结构和数量的变化,阐述农药对土壤微生态环境的影响。方法收集长期使用农药的土壤和未使用农药的土壤,提取细菌基因组DNA,采用针对16S r DNA V3区的PCR-DGGE技术获得土壤菌群指纹图谱,进行相似性、多样性分析。结果长期使用农药的实验组土壤菌群结构与正常组比较差异有统计学意义(P0.05)。长期使用农药的土壤中出现四种特异性菌种:Candidatus saccharimonas、Anabaena cylindrical、Caldilinea aerophila和Sphingobium chlorophenolicum。Streptomyces niveus、Thermoanaerobacter菌种在长期使用农药的实验组含量增多,且差异均具有统计学意义(P0.01)。结论长期使用农药在一定程度上使土壤细菌种群的结构和数量发生变化,破坏了土壤微生态平衡。     

有机磷农药对人类健康的影响及农药残留检测方法研究进展

随着工农业生产的发展, 社会与生态环境环境对人类健康的影响愈来愈大。环境污染严重影响人类身体和心理健康。对有机磷农药的生产及使用现状, 有机磷农药的结构和毒性作用, 有机磷农药残留对生态环境的污染和对人类健康的危害以及检测方法进行了探讨, 以期为有机磷农药的安全使用和农药残留检测提供参考依据。     

农药规格与使用技术的配合问题

几年来农药治虫的规模,已由重点示范逐渐发展到全国各地农村,使用数量,亦年有增加,有些害虫如蝗虫,地下害虫、棉虫等,几乎完圣采用农药防治,因此,农药成为保证农业丰产的一项主要生产资料。但是,随着农药使用范围的扩大,带来了规格质量和使用技术的落後问题,因而在治虫工作中不断发生药害和失效等事故,以致影响农药治虫的推广与发展。这是当前治虫事业中存在的一个严重问题。     

我国绿色农药研究现状及发展建议

农药是保障粮食安全的战略性物资,但农药的不合理使用造成了农产品质量安全和生态环境安全等重大问题.绿色农药是根据绿色化学理念,采用环境友好的绿色原料,生产开发的更安全的农药.近年来,我国在绿色农药领域的研究实现了多个突破,极大提高了我国绿色农药原始创新能力,促进了我国农药产业的可持续发展.然而,我国农药产业的发展仍面临着诸多挑战.本文介绍了农药产业的国内外发展现状,绿色农药创制的研究进展和我国在农药产业上面临的问题,并从不同的角度提出了相应的建议.     

乐果对四尾栅藻碳、氮、磷营养缺乏的替补效应

有机磷农药属于有机磷化合物的范畴,一般是指磷(膦)酸酯、硫代磷酸酯、磷酰胺酯类有机磷化合物。因其具有杀虫力强、使用范围广、残留期较短等特点,从20世纪80年代开始,有机磷农药很快就取代了有机氯农药成为我国农药市场份额最大,使用最多最广的一代新生     

江西植物性农药资源及其利用

介绍了江西民间使用的30种植物性农药,并对利用植物性农药提出建议.     

农药对农区生物多样性的影响

农药的大量使用,已造成了许多生态环境问题,其中对生物多样性的影响尤为重要．农药的不合理使用,对生物群落的结构与功能产生了严重影响,降低了生物多样性．从昆虫群落结构、土壤中无脊椎动物种群数量、微生物区系和植物群落等方面论述了农药对农业区域生物多样性的影响,并提出了合理使用农药。保护农业区域生物多样性的具体措施．     

农药的发展与人类的健康

农药与人类的健康密切相关,它是造成人类疾病增多的原因之一,也是人们谈论的热点话题之一,人们往往把“农药”视为“毒药”。本文通过介绍常用农药给环境和人类健康造成的危害,提出在“白色农业”的发展下,应大力开发和使用微生物农药,逐步消除农药产生的公害问题,以纠正人们对农药的片面认识。     

广州地区农产品中有机磷农药残留调查

采用国家标准方法气相色谱(GC)法进行分析,通过对蔬菜、水果、粮食中16种有机磷农药残留量的检测,了解有机磷农药在广州地区农产品中的残留及其分布情况.50份农产品样品中有机磷农药各组分总的检出率为96.0%,其中蔬菜、水果、粮食检出率分别为96.8%、100%、80.0%.50份农产品样品中有机磷农药各组分总的超标率为36.0%,其中蔬菜、水果、粮食超标率分别为41.9%、21.4%、40.0%,16种有机磷农药中以马拉硫磷的超标率最高,为32.0%.不同组分有机磷农药在农产品中的残留量,以杀螟磷的平均含量最高,为1308.7μg·kg^-1,其次是辛硫磷和甲胺磷,分别为970.1μg·kg^-1和737.6μg·kg^-1;因此应提倡合理使用农药,加强农药使用的引导和监管.     

农用化学品污染及预防建议

农用化学品是农业生产的重要组成部分,其安全问题也成为人们关注的焦点。农用化学品可分为化肥、农药、农膜3类。化肥主要用于提高土壤肥力,增加农作物产量,不合理使用则会改变土壤性质,降低土壤肥力,并且对生态环境以及人类健康造成不可忽视的危害。农药主要用于杀菌、杀虫、除草等,在促进和保障农作物健康生长中发挥重要作用,但农药的滥用造成农药事故频发,农药的毒性富集作用以及残留问题越发引起人们的关注。农膜主要用于农膜覆盖栽培技术,农膜的原料主要是聚乙烯树脂等高分子化学物质,在土壤中很难降解,造成的环境污染问题日益突出。各种农用化学品的不合理使用,可降低农产品的质量,使其在出口贸易中受到极大限制,造成巨大的经济损失。本文在肯定农用化学品在现代化农业生产中的巨大贡献的同时,深入分析了其污染状况及危害,总结了当前国际上对于化肥、农药、农膜的研究进展以及所取得的成果,最后提出了科学使用农用化学品的建议。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.