飞虱虫疠霉杀蚜效果及开发应用前景

通过比较飞虱虫疠霉 (Pandoradelphacis)与其它几种常见蚜虫专化性病原真菌新蚜虫疠霉(P .neoaphidis)、安徽虫瘟霉 (Zoothphoraanhuiensis)和根虫瘟霉 (Z .radicans)对桃蚜 (Myzuspersicae)毒力 ,证实了该菌的杀蚜应用潜力。时间 -剂量 -死亡率模型分析表明 ,飞虱虫疠霉杀蚜的各项毒力指标与其它几种虫霉相似或略高 ,但杀蚜速率更快。同时对培养性状、产孢特性和生长适温等的比较研究发现 ,该菌具有易发酵生产、产孢能力强和温度生长范围宽等特点 ,是一种较为理想的有望研制开发成杀蚜真菌制剂的病原菌。此外 ,根据虫霉孢子主动弹射的生物学特性 ,提出了该菌的适用剂型 ,并对它们的流行学特性及其在设栽培中的应用前景进行了讨论。     

块状耳霉的分离、鉴定、培养和寄主范围

1981年自感染真菌的扁豆蚜(Aphis craccivora Koch)虫尸上分离到一株虫毒菌,经鉴定是耳霉属的块状耳霉(couidiobolus thromboides Drechsler)。该菌易于分离和培养,在培养基上可形成大量休眠孢子,休眠孢子容易萌发,六天中萌发率达53%。经试验该种虫霉可以感染多种蚜虫,是一种有希望制成杀蚜菌剂的真菌。     

根虫瘟霉和相关种的分类地位研究及其ITS核苷酸序列分析

根虫瘟霉是最常见的一种虫霉,寄主广泛,世界广布。目前有学者认为该种是个复合种。本研究对世界不同地区和不同寄主的根虫瘟霉及其近缘类群总计19个菌株,进行3个靶位点（ITS、LSU rDNA、RPB2）的分子系统发育学分析。结果显示,根虫瘟霉ITS长度较为保守性,介于1 321-1 324bp之间,而所研究的虫霉亚门的其他类群的长度范围较大,为556-1 654bp。本研究确认根虫瘟霉是单系种,同时西虫瘟霉、矛孢虫瘟霉和英吉利虫瘟霉具有明确种的分类地位。鬼笔状虫瘟霉种应该被视为西虫瘟霉的异名。     

虫霉真菌分类系统名录

虫霉真菌是低等真菌的重要成员,目前包含280余种,多为节肢动物的专性寄生真菌,少数腐生于土壤和枯枝落叶。本文在Humber发表的虫霉真菌分类框架上,结合近期发表的虫霉真菌分类单元,对该类真菌分类系统名录进行更新,介绍了1门、3纲、3目、10科和25属的分类学特征,并对当前虫霉真菌分类存在的问题进行了总结和展望。     

双玻片插片诱导新西兰匍柄霉产生分生孢子的方法

匍柄霉属(Stemphylium)是重要无性丝孢真菌类群,多数种菌难以诱导产生适宜形态学分类研究的分生孢子。以新西兰匍柄霉(Stemphylium eturmiunum)为材料,经适宜培养后(PDA培养基,25℃培养3~4 d),将双玻片斜插入生长适量菌丝的平板,延续培养3~4周后,进行玻片制作和显微描述,结果发现双玻片插片诱导培养处理后,匍柄霉种菌易产生充分发育的产孢细胞、产孢梗及适量的无性分生孢子。该技术方法简便易行,避免了选择性培养基诱导产生的缺陷,适宜于匍柄霉及其近似属若干难以产生无性分类特征的分类研究,为系统开展该类真菌系统分类研究提供技术借鉴。     

中国腐霉属的水生种类

腐霉属是一个世界广布分类群,迄今为止已报道约100种.它们主要分布于土坡中,条件适合时侵染植物引起病害,造成多种经济植物的重大损失.腐霉也见水中,它们既可寄生于藻类及一些小动物上,也可腐生于动植物残骸上.在研究微生物与水质关系时,腐霉的作用是不可忽视的.在发酵工业上,腐霉可望用于生产多种酶类及转化街族化合物,所以它是一个经济意义较重要的类群.     

线虫草科弯颈霉属研究进展

弯颈霉属Tolypocladium是W. Gams于1971年建立的新属,该属的特点是瓶梗基部呈球形或椭圆形膨大,瓶颈细长而弯曲,分生孢子单生或黏聚成小头状,截至目前国际真菌名录数据库中记录弯颈霉属真菌有43种。其模式种为膨大弯颈霉Tolypocladium inflatum W.Gams。弯颈霉属是一类重要虫生真菌,生态分布广,寄主种类多,弯颈霉属很多种被发现是虫草属无性型,与虫草属的关系十分密切,2014年一些国际著名真菌学家基于分子生物学的新分类系统将弯颈霉属归入到线虫草科Ophiocordicipitaceae。弯颈霉属能产生多种杀虫和抗菌的有效成分,如环孢菌素(Cyclosporin)、大团囊素(Ophiocordin,蛋白酶强抑制剂)、线肽素(efrapeptin)、四聚胺酸素(Ophiosetin)、多种杀虫剂等。文中综述了弯颈霉属真菌的分类、生活习性与生态分布等,介绍了其药理药效及有效化学成分等相关研究,并展望了弯颈霉属真菌的研究发展前景。     

盾壳霉产生几丁质酶的条件研究

本实验采用摇瓶培养研究了盾壳霉(Coniothyrium minitans)产生几丁质酶的条件。改良的天然马铃薯葡萄糖培养基(mPDB)较合成培养基(SMCS)更适宜作为盾壳霉产生几丁质酶的基础培养基。添加9种不同碳源试验表明葡萄糖较适宜于盾壳霉产几丁质酶;氮源试验表明硝酸钾是产酶的较适宜氮源。盾壳霉形成几丁质酶的培养时间以15 d为佳,培养的适宜pH值为6.5。     

木霉现有种类名录

木霉因其在酶、抗生素及生防等方面有着重要的经济生产价值而得到世界广泛的研究和关注。截止目前,已报道木霉种类达到212种,准确对其进行分类和鉴定对于木霉的研究和利用有着重要的意义。本文整理了目前已报道的木霉种类名录及用于木霉系统发育种类鉴定的分子技术和工具,这些技术和工具为木霉研究者对木霉进行准确种类鉴定提供技术指导和帮助。     

虫霉目新种和新记录

本文报道了虫霉目的一个新种和3个新记录种。新种叶蝉虫疫霉(Erynia cicadellisLi et Fan sp.nov.)是我国南方稻叶蝉虫霉流行病的病原之一,与近缘种飞虱虫疫霉[E．Deiphaeis (Heri) Humber et Ben-Ze’ev] 的主要区别在于后者孢子较大,且不具有假根。蚜虫疫霉[E. aphidis (Hoffm.) Humber et Ben-Ze'ev]系世界不常见种,国内首次在陕西岚皋及福州的桃蚜上记录;飞虱虫疫霉和佩氏虫疫霉[E．Petchii Ben-Ze'ev et Kenneth)皆系南方褐稻虱虫霉流行病的病原。     

Some advances in the study of lichens since the time of E. M. Holmes

Some of the principal advances in our knowledge of lichens made since the time of E. M. Holmes are briefly reviewed. Floristic studies on British lichens have continued and distribution maps of particular species are now being produced. These studies have shown that many species have disappeared from areas affected by air pollution by sulphur dioxide. Lichen taxonomy has seen the acceptance of chemical characters as valid taxonomic criteria, and the realization that ascus types, ascocarp structure and ascocarp ontogeny are more important at the generic level than ascospore characters alone. Lichens are not now thought of as a single taxonomic group but as fungi related to various orders of non-lichenized Ascomycotina, united only in their common method of nutrition (symbiosis with algae); some lichenized and non-lichenized species with identical types of ascocarps are consequently being treated as members of the same genus. Considerable progress has been made in describing lichen communities characteristic of particular substrates and situations and in understanding the factors which may affect the occurrence of particular species. Lichens have proved to be particularly valuable indicators of mean air pollution levels and scales for the estimation of these levels based solely on the lichen vegetation have been devised. Physiological and ultrastructural studies on lichens have progressed rapidly in the last decade. Carbohydrates have been demonstrated to move from the algal to the fungal component and the mobile carbohydrates found to differ in lichens with different genera of algae. The algal and fungal partners have been isolated and studied in pure culture. Most attempts to synthesize lichens have met with little success but in 1970 a thallus was formed from its components in culture. It is now possible to grow some lichens under controlled conditions in the laboratory and these techniques, together with transplant experiments, will clearly assume considerable importance in the investigation of taxonomic and ecological problems in the future. Little progress has been made in the study of lichen cytology or the factors affecting the establishment of lichen thalli. Lichens constitute an important part of some ecosystems and their decline due to anthropogenic influences is consequently a matter of concern for all biologists.     

Chemicals in aroids: a survey, including new results for polyhydroxy alkaloids and alkylresorcinols

The Araceae is a large, mainly tropical family, many members of which contain bioactive substances which are often either toxic or irritating. Inflorescences frequently emit strong fragrances. The active compounds have not been adequately determined nor is the chemotaxonomy of the family very well known, except for one major study of flavonoids. Two groups of compounds of known bioactivity–alkylresorcinols and nitrogenous sugar analogues–have been sought in representative species from most of the genera in the family. Although percentage sampling was necessarily small, a few examples of species containing these substances were found and some taxonomic suggestions are made and compared with results in the literature. This survey is a basis for further work on the family.     

Chemicals in aroids: a survey, including new results for polyhydroxy alkaloids and alkylresorcinols

The Araceae is a large, mainly tropical family, many members of which contain bioactive substances which are often either toxic or irritating. Inflorescences frequently emit strong fragrances. The active compounds have not been adequately determined nor is the chemotaxonomy of the family very well known, except for one major study of flavonoids. Two groups of compounds of known bioactivity—alkylresorcinols and nitrogenous sugar analogues—have been sought in representative species from most of the genera in the family. Although percentage sampling was necessarily small, a few examples of species containing these substances were found and some taxonomic suggestions are made and compared with results in the literature. This survey is a basis for further work on the family.     

DISTRIBUTION OF VERTEBRATES IN THE SILURIAN OF ESTONIA

A rich collection of Silurian vertebrate remains, including abundant thelodont and acanthodian scales, has been made from recent borings on the Estonian island of Saaremaa (Ösel). Thelodonts have been reported for the first time at the top of the Jaagarahu Stage, as have anaspids from the Rootsiküla (formerly Kaarma) Stage, and acanthodians from the Paadla Stage. Arthrodires as well as actinopterygians (?), represented by the genus Andreolepis, have been found for the first time on Saaremaa. Arthrodires appear to be the oldest known members of this group. The recent stratigraphical classification of the Silurian of Estonia has been taken into account, and the stratigraphical distribution of the vertebrate genera and species is given. The correlation between some of the vertebrate-bearing beds of Saaremaa, Gotland, and the southern Baltic is also discussed.     

Nitric oxide production in agricultural soils

Numerous papers on nitric oxide have been published covering various aspects ranging from its solution and gas-phase chemistry, biochemical and physiological functions and atmospheric processes. This review emphasizes recent developments in the literature relating to NO/NOx production in agricultural soils. We have tried to minimize overlap with other recent and relevant review articles. Emission measurements that have been made since 1992 are tabulated and discussed in terms of variability, fertilization effects, and advances made in monitoring fluxes. We describe attempts made by a number of authors to utilize ecological markers such as aeration, water, ammonium, nitrate content, etc. in order to distinguish between nitrification and denitrification as the primary source of production and/or consumption in natural field situations. This may allow a rational accounting for the high spatial and temporal variability observed, and the formulation of reliable predictive models. Factors such as diffusion, oxygen, water, and carbon (content and quality) that regulate or significantly influence production, consumption and emission are discussed. Finally some important implications of recent research relating to nitrification and denitrification is presented showing the chemical oxidation of NO which could occur when the acetylene inhibition technique is used.     

PHYLOGENYOF THE VLE-14 CHLAMYOMONAS (CHLOROPHYCEAE) GROUP: A STUDY OF 18S rRNA GENE SEQUENCES1

Comparative specificity of sporangial wall autolysins (i.e. vegetative lytic enzymes [VLE]) derived from sporulating cultures has been used to group Chlamydomonas taxa into 15 different VLE types. The VLE-14 group, including isolates of C. geitleri, C. noctigama, C. monoica, C. pinicola, C. terricoia, and C. hindakii, is one of the largest of these VLE groups. Genetic studies have shown that a number of the VLE-14 taxa are interfertile, albeit with little or reduced viability of progeny. A reevaluation of the VLE-14 group suggested that all members should be regarded as distinct isolates of C. noctigama. The present investigation tests the phylogenetic implications of the VLE evidence and examines the validity of the taxonomic reevaluation in a phylogenetic context by analysis of 18S rRNA gene sequence data. Results from analyses of the sequence data are consistent with an interpretation of the VLE evidence as indicative of monophyletic taxa. Phylogenetic analyses of the sequence data are also consistent with the taxonomic reevaluation and reidentification of the group. However, at least some of the VLE-14 isolates studied in this investigation fit criteria for distinct biologic or phylogenetic species. It is concluded that the VLE-14 taxa represent a very closely allied group that includes some isolates that are in the early stages of speciation ly reproductive isolation.     

TISSUE CULTURE IN THE PRODUCTION OF NOVEL DISEASE-RESISTANT CROP PLANTS

1. Plant tissue cultures form the basis of a number of techniques which have been developed to effect genetic changes in plants. Progress is being made in the application of these techniques in breeding new, disease-resistant cultivars. 2. It is possible to induce and select for mutants among populations of cultured plant cells. Novel disease-resistant plants of a small number of species have been regenerated from cells selected in culture for their resistance to toxins produced by pathogens, both with and without prior exposure to mutagens. It is not known whether such procedures are widely applicable, and the nature of the genetic changes involved has not yet been determined. 3. The tissues of plant species which are propagated vegetatively are normally genetic mosaics with regard to many characteristics, including resistance to disease. Thus, some of the plants regenerated from cultured cells of such species are more resistant to pathogens than the parent plants. Novel plants produced in this way are already being used in some breeding programmes. 4. Many attempts have been made to modify the genomes of cultured plant cells by means of exogenous nucleic acids. The evidence for integration and replication of this genetic material is equivocal. The technique, therefore, offers no immediate prospects for the development of novel disease-resistant plants, but may be important in the long term as methods are perfected for using plasmids and other agents as carriers of useful genes. 5. Steady advances are being made in producing somatic hybrids of crop plants by fusion of isolated protoplasts. In the long term it may be possible to use protoplast fusion to transfer desirable disease-resistance traits between related species which cannot be hybridized by conventional breeding methods. 6. The culture of excised embryos may be used to grow interspecific and inter-generic hybrid plants in cases where incompatibility occurs after normal fertilization. The technique is already being used by breeders in the production of disease-resistant hybrids of crop species. 7. It is concluded that tissue culture has a limited but useful role to play in the development of novel disease-resistant crop plants.     

中国蹄盖蕨属的研究Ⅰ-属下分类

蹄盖蕨属是蕨类植物中分类最困难的大属之一,中国、喜马拉雅和日本为其分布中心。隶属于本属的种实际上是由蹄盖蕨科或广义蹄盖蕨属中其他属被划分出去以后剩余下来的种类集合而成的"大杂烩",因此,它们被放在一起并非是一个单系起源的自然类群;属下不同类群分化的程度相差也很大,有的类群进化活跃,近缘种很多,有的类群则很孤立,所以属下单位所包括的种数相差悬殊;孢子周壁表面褶皱的有无在本属的属下分类中占有重要的位置。已发表的中国蹄盖蕨属植物名称约有300多个,它们初步被处理为117种和一些变种和杂种,本文建议把这些种分为14个组和15个系。     

Ecology and genetics of tropical rhizobia species

Biological nitrogen fixation (BNF) technology with special reference to Rhizobium-legume symbiosis is growing very rapidly with the hope of combatting world hunger by producing cheaper protein for animal and human consumption in the Third World. One can see rapid progress made in the biochemistry and molecular biology of symbiotic nitrogen fixation in general; however, less progress has been made on the ecological aspects despite the fact that an enormous amount of literature is available on inoculation problems and on agronomic aspects of symbiotic nitrogen fixation. So far most information on Rhizobium concerns fast-growing rhizobia and their host legume. Although it is essential that food production using BNF technology should be maximized in the Third World, the least work has been done on slow-growing rhizobia, which are generally found in tropical and sub-tropical soils. The majority of the developing countries are in tropical and sub-tropical regions. Except for R. japonicum, a microsymbiont partner of soybean (Glycine max), the majority of the slow-growing rhizobia belong to the cowpea group, and we refer to cowpea rhizobia as tropical rhizobia species. In this review we have tried to consolidate the recent progress made on ecology and genetics of tropical rhizobia. By using recombinant DNA technology techniques it is expected that super strains of rhizobia with desirable characteristics can be produced. One must evaluate the efficiency and effectiveness of these genetically manipulated laboratory strains under field conditions. In conclusion, if one aims at combatting hunger in the Third World using BNF technology, an intensive research programme on fundamental and applied aspects of tropical rhizobia species is suggested. This involves close cooperation between molecular biologists and microbial ecologists.     

Dimorphic spore production in the genus Acaulospora

Species of the genus Acaulospora are partly characterized by the production of ‘acaulosporoid’ spores. The simultaneous formation of glomoid and acaulosporoid spores by some species in the Glomeromycota has been used as a basis for taxonomic classification. We report the presence of both glomoid and acaulosporoid spores in four Acaulospora species. Analysis of the 18S rRNA gene confirmed that only A. spinosa was present in a pot culture that produced two morphs. The functional significance of dimorphic spore production is unknown but the production of blastic spores is not a characteristic that can have any significance as a taxonomic character.