根瘤菌菌剂的研究与开发现状

根瘤菌与豆科植物共生成为豆科植物固氮的重要方式,它可以为豆科植物提供所需氮量的1/2～1/3。因此,土壤中有效根瘤菌的数量是决定豆科植物产量的重要因素,而根瘤菌菌剂的使用可以有效地提高土壤中根瘤菌数量。本文从根瘤菌菌剂制备中高效菌种的选育及匹配、高密度菌剂的制备、菌剂保存方法等方面进行综述。比较了自然选育、杂交选育和诱变选育等各类选育方法及琼脂试管配对法和水培配对法的优缺点;总结了菌剂制备的一般过程和方法;论述了菌剂保藏过程中冷冻干燥法和各种保护剂的使用对菌剂保藏效果的影响。本文阐述了根瘤菌菌剂的制备工艺和发展方向,为根瘤菌剂的研制提供重要参考。     

草木樨根瘤菌(Rhizobium meliloti)高效菌株筛选初报

草木樨是辽宁西部主要的牧草绿肥品种。目前生产上存在着前期生长缓慢,产草量低的问题,施用根瘤菌肥料对促进生长,提高鲜草产量有重要作用。为此,我们自1980年开展了草木樨根瘤菌优良菌株筛选工作。现将1980年—1981年筛选结果整理如下。一、草木樨根瘤菌菌种形态及培养特     

生物肥料在辽宁省的应用

生物肥料在辽宁省的应用宋玉清,马麟祥（辽宁省农业科学院土肥所微生物研究室,沈阳１１０１６１）我省对自生固氮菌和根瘤菌在农业上的应用进行了一系列工作,研究了圆褐固氮菌在不同土类中的生态分布和大豆、花生、碗豆、草木栖根瘤菌的菌种选育和有效施用技术,菜豆根...     

花生根瘤菌高效菌剂的研究

我国在豆科作物上应用根瘤菌接种措施至今已近40年。实践证明,花生在播种时,人工接种根瘤菌,一般能增产10％左右。但这一优势在花生生长期,从外观上难以察看出来,这直接影响着花生根瘤菌剂大面积推广应用。考虑到稀土元素和石油助长剂等所具有的生理活性特点以及与根瘤菌剂配合施用的效果,特开展本项研究,以提高菌剂的应用效果。     

大豆根瘤菌突变株的细菌学鉴定(简报)

大豆根瘤菌优良菌种的选育,对提高根瘤菌的接种效果起着重要的作用。以往大都从自然界筛选的办法来获得高固氮高结瘤率的菌株,R. L. Maier等人应用诱变的手段对美国商业用大豆根瘤菌进行处理,得到的诱变菌株较野生菌株结瘤早、固氮力高,在生长室内并能提高植株     

生态工程领域微生物菌剂研究进展

阐述了微生物菌剂在生态工程领域的应用范围、效果和国内外的研究状况,总结了目前微生物菌剂研制中菌种的选育方法和常用的几类菌,并通过系统举例介绍了乳酸菌、酵母菌、光合细菌、芽孢杆菌这些常用菌种在污染物处理方面的效果及在废水处理生态工程方面的相关研究进展。同时,阐明了微生物混合培养技术在复合菌剂研究中的重要性,对微生物菌剂的作用机理进行了探讨,指出了目前关于微生物菌剂的研究大多只是集中于应用效果方面,而对作用机理研究得不够深入,以及复合菌系中微生物相互作用和影响的复杂性,并对此提出了一些建议。最后,对微生物菌剂的应用前景进行了展望。     

1株高效花生根瘤菌的筛选与鉴定

从辽宁多地花生种植土壤及其鲜根瘤初步筛选到30株花生根瘤菌,进一步通过回接盆栽花生,测定花生根瘤数、根瘤干重,以及鲜根瘤固氮酶活性、植株全氮量等,筛选出1株结瘤固氮能力较强花生根瘤菌wz-6,通过16S rDNA序列分析,鉴定为圆明慢生根瘤菌(Bradyrhizobium yuanmingense)。为开发优质花生根瘤菌菌剂奠定基础。     

我国豆科植物根瘤菌资源多样性及应用基础研究

北京农业大学菌种保藏中心(CCBAU)现已保藏根瘤菌5000余株,是全世界最大的根瘤菌资源数据库。通过对其中的2000余株根瘤菌作多相分类研究,确定根瘤菌新属2个、新种11个。结合根瘤菌宿主及其生态环境的关系,提出根瘤菌与豆科植物共生关系的新认识;并得出豆科植物接种根瘤菌的新见解,这对于西部大开发中新区种植豆科植物接种适宜的根瘤菌具有重要指导意义。     

新型的根瘤菌剂—油菌剂的研究

根瘤菌使用效果,关键在于菌剂质量。目前生产的菌剂,其剂型落后,运输不便(如琼脂、泥炭菌剂),且不耐干旱高温。采用丸衣化接种,在一定程度上可耐高温干燥,但仅适合某些厚皮种子。对一些皮薄的花生、大豆种子,种皮常遭破损而影响发芽率。因此,研究适宜的剂型,是当前迫切需要解决的课题。     

荷兰豆根瘤菌的分离、鉴定及其菌剂的研制和应用

本文对南方出口蔬菜-荷兰豆的根瘤菌进行分离、鉴定及其菌剂的研制和应用的研究．结果表明,所分离的菌株能适应本省的不同类型的土壤环境,与荷兰豆中的多个品种结出有效根瘤,盆栽试验结瘤率达到100％,大田应用在90％以上;接种了该菌株,能使荷兰豆植株较高大粗壮、分枝多、有效花多、结荚数增加、产品的质量提高,大田应用的增产率可达14％,产品一级率可提高10％左右。大田试验结果表明,施用该菌剂,可减少氮肥的施用量,降低生产成本,从而提高荷兰豆生产的经济效益．     

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.