大麦根中禾谷多粘菌休眠孢子堆的超微结构

通过扫描电镜和透射电镜观察了禾谷多粘菌PolymyxagraminisLed．休眠孢子堆的超微结构。休眠孢子堆仅分布于寄主根表皮细胞中。休眠孢子堆形状不一,有的呈球状,有的呈律状,少则由几十个,多则由数百个紧密排列的休眠孢子组成。休眠孢子彼此通过刺突连接,细胞壁分4层,第三层局部区域结构松散,可能与初生游动孢子萌发孔有关。成熟休眠孢子细胞质丰富,细胞质膜内侧含有大量脂质粒,细胞质中央含一个细胞核,围围分布线粒体、内质网、高尔基体、液泡等细胞器。成熟的休眠孢子在越夏前大多数已释放初生游动孢子,只剩下空壳。表面凹陷是已释放游动孢子的休眠孢子一个特征。本文还讨论了禾谷多粘菌休眠孢子在病害流行学中的作用。     

大麦根中禾谷多粘菌休眠孢子堆的超微结构

通过扫描电镜和透射电镜观察了禾谷多粘菌Ｐｏｌｙｍｙｘａ ｇｒａｍｉｎｉｓ Ｌｅｄ。休眠孢子堆的超微结构。休眠孢子堆仅分布于寄主根表皮细胞中,休眠孢子堆形状不一,有的呈球状,有的呈棒状,少则由几十个,多则由数百个紧密列的休眠孢子组成。     

禾谷多粘菌对小麦梭条斑花叶病毒的传播及其土壤侵染潜力的测定

从大田侵染小麦梭条斑花叶病毒的小麦病根中挑取禾谷多粘菌休眠孢子堆,接种受侵染小麦品种扬麦４号,经砂培养纯化,获得５个禾谷多粘菌分离物,但都为无毒。无毒多粘菌休眠孢子堆接种表现ＷＳＳＭＶ症状的小麦,经培养可饲获病毒,并可经接咱后将病毒传播给无病小麦,供试的４个大小麦禾谷多粘菌分离物都可对大小进行交叉侵染,产生同样数量的游动孢子产量。供试５个病土和２个无病土样品,都具有强大持多粘菌侵染潜力,即使稀释放     

砂培体系中甜菜多粘菌生物学特性的研究

在改进的砂培体系中,甜菜多粘菌（Polymyxabetae）完成生活循环只需7天。利用砂培体系研究了多粘菌在不同pH值、光照、接种材料和接种量条件下,对寄主的侵染以及在其中繁殖的情况,研究了多粘菌完成侵染所需时间,侵染的游动孢子最初释放时间,游动孢子体外存活期和休眠孢子对温度的敏感性等生物学特性。     

禾谷多粘菌游动孢子超微结构观察

本文描述了寄生在大麦根部的禾谷多粘菌Polymyxa graminis Led.的次生游动孢子的超微结构,包括核、内质网、高尔基体、线粒体、脂质粒、排泄泡、小囊、具膜小囊、核糖体以及鞭毛基体(Kinetosome)和鞭毛杆等细胞器。游动孢子中未见微体。同时也在电镜下观察了游动孢子接触和穿透根细胞时所形成的管腔(Rohr)和棘杆(Stachel)以及游动孢子穿透细胞壁的详细过程。     

砂培体系中甜菜多粘菌生物学特性的研究

在改进的砂培体系中,甜菜多粘菌完成生活循环只需７天。利用砂培体系研究了多粘菌在不同ＰＨ值、光照,接种材料和接处量条件下,对寄主的侵染以及在其中繁殖的情况。 多粘菌完成侵染所需时间,侵染的游支孢子最初释放时间,游协孢子体外存活期和休眠孢子对温度的敏感性等生物学特性。     

甜菜多粘菌形态发育过程研究

甜菜多粘菌(Polymyxa betae)是一种专性寄生于甜菜根部的低等真菌,可作为甜菜坏死黄脉病毒(BNYVV)的传播介体并与甜菜丛根病的产生有关。对甜菜多粘菌的研究有助于了解其与所传病毒的生物学关系及其在引致甜菜丛根病中所起的作用。本文观察记录了甜菜多粘菌侵染甜菜根系及其在甜菜根细胞中的发育过程,对甜菜多粘菌各主要发育阶段进行了显微镜观察并发现在其游动孢子中有BNYVV粒体存在。根据观察结果并提出了甜菜多粘菌生活史模式图。     

印度雕蚀菌对三带喙库蚊幼虫生活力的影响

三带喙库蚊幼虫为印度雕蚀菌的寄生宿主,自然界中2—4龄幼虫均可感染印度雕蚀菌,感染后幼虫体肿胀,活动缓慢,对外界抵抗力降低,各龄幼虫虽可蜕皮,但在蜕皮过程中即行死亡。幼虫存活时间各为:2龄的5天;3龄的4—11天;4龄的4—9天,死亡率达100%。印度雕蚀菌的初生孢子囊和休眠孢子囊不同,可充满于幼虫的血腔,二型孢子囊的数量以前者为多,死亡虫体中多为成熟孢子囊,囊内可见有成熟而极为活跃的,带有鞭毛的游动孢子。经1—2小时,成熟游动孢子破囊而出,游动于水体中。 病态蚊幼主要滋生于有机物质丰富,水质清澈的秧稻田中。连续3年观察,其滋生地多为固定而局限,未发现与三带喙库蚊滋生同一地的中华按蚊和它种蚊虫的感染。     

细弱绒泡菌的生活史

利用燕麦-琼脂培养、基物培养及扫描电镜技术研究了细弱绒泡菌的个体发育过程,在燕麦琼脂培养基上完成了从孢子到孢子的生活史。结果表明,细弱绒泡菌生活史包括单核的黏变形体或游动胞、多核的营养体原质团以及孢子形成阶段。孢子球形,表面具细小疣点。孢子萌发为裂式,释放1黏变形体。黏变形体行变形运动,在有水的条件下,可转变为游动胞。成熟原质团橘黄色。原质团类型为显型,具有扇形网络状菌脉。成熟原质团可形成多个孢囊。琼脂培养基上获得的细弱绒泡菌孢子与野生型相似,并具有可育性。     

绵马鳞毛蕨精母细胞和游动精子超微结构特征的研究

应用电镜技术对蕨类植物绵马鳞毛蕨(RYOPTERIS CRASSIRHIZOMA Nakai)精母细胞和游动精子的超微结构特征进行了研究。精母细胞为多边形,细胞质内含有丰富的线粒体、质体、内质网、高尔基体等常见的细胞器．在细胞质中还可见到一些同心圆膜状结构,位于质膜的附近或精母细胞的角偶。同心圆膜状结构由双层膜环绕构成,外被l层单位膜。精母细胞与精子器的璧细胞之间形成了分离腔。在精母细胞质膜外形成了嗜锇层,这些结构的形成说明精母细胞已经开始与雄配子体逐渐分离,进入独立发育的阶段。尽管精母细胞之间也有嗜锇层的形成,但嗜锇层是不连续的,其上有一些空隙,精母细胞之间可通过空隙进行物质和信息的交流。成熟的精子细胞外被l层透明的薄膜,里面为游动精子。螺旋状。由环状细胞器环绕3～4圈构成．这些环状细胞器包括多层结卡构、微管带、巨大线粒体、鞭毛带和1个长形浓缩的细胞核。游动精子的后端为一些泡囊化的细胞质．其中包括一些残存的线粒体、造粉质体及大的囊泡等。当成熟的精子细胞排出精子器后。其内的游动精子挣脱透明质膜的束缚,摆脱后端的囊泡,成为1条游动精子。本文还对绵马鳞毛蕨和其它蕨类植物精子的超微结构特征进行了比较。     

Evaluation of Trichoderma spp. from central and northern regions of Turkey for suppression of Polymyxa betae as a vector of rhizomania disease

In the current study, 18 Trichoderma spp. isolates were obtained from different provinces in central and northern regions of Turkey. The ability of nine selected isolates to suppress the colonisation of roots by P. betae and the multiplication of BNYVV in sugar beet roots under controlled conditions were tested. Roots of seedlings growing in the P. betae-BNYVV-infested soil were analysed by enzyme-linked immunosorbent assay to test for the presence of BNYVV and checked microscopically for the density of cystosori of P. betae. The numbers of P. betae resting spores in cystosori for each treatment were counted using a light microscope. Except for isolates Tr-1 and Tr-5, the effect of selected Trichoderma isolates on suppressing multiplication of BNYVV varied between 4 and 53%. The total number of resting spores in the roots varied between 14.4 and 25.1 for the different Trichoderma spp. treatments. The lowest number of resting spores in clusters was recorded in T. harzianum Tr-8. In addition, the shapes of resting spores were not normal in the Tr-8 treatments. The cystosori from this treatment were also abnormally dark in colour and had deformed walls.     

Confirmation of the transmission of barley yellow mosaic virus (BaYMV) by the fungus Polymyxa graminis

Resting spores (cystosori) of Polymyxa graminis, selected from roots of barley plants infected with barley yellow mosaic virus (BaYMV), were used to start mono-fungal sand cultures. Out of 20 attempts using over 800 cystosori, P. graminis became established in 12, and in two of these BaYMV symptoms also occurred. BaYMV was detected by ELISA in extracts of dried roots heavily infected with cystosori and in zoospores of P. graminis. Calculations suggested that, on average, each zoospore carried less than 100 virus particles. In two virus acquisition experiments, non-viruliferous isolates of P. graminis failed to acquire BaYMV from roots of mechanically-inoculated plants. In two further experiments, non-viruliferous isolates were grown on rooted tillers produced from healthy plants and those infected with BaYMV by either vector or mechanical inoculation. Zoospores and cystosori of P. graminis subsequently transmitted the virus, but only from plants where it had been introduced by the vector. Repeated mechanical transmission appeared to have selected a strain of virus that could not be acquired and/or transmitted by the vector. The results provide convincing evidence that P. graminis is a vector of BaYMV but suggest that, in natural populations, only a small proportion of spores may be viruliferous.     

STUDIES ON THE LIFE CYCLE AND TAXONOMY OF LIGNIERA VERRUCOSA

Miller , Charles E. (A. and M. College of Texas, College Station.) Studies on the life cycle and taxonomy of Ligniera verrucosa. Amer. Jour. Bot. 46(10): 725–729. Illus. 1959.—A study of the roots of Veronica persica Poir. and V. hederaefolia L. plants infected with Sorosphaera veronicae Schroeter revealed intracellular cystosori and zoosporangial sori of Ligniera verrucosa. The zoosporangial phase of this species has been heretofore unknown. The plasmodia of L. verrucosa occur in root hairs, and other epidermal and sub-epidermal cells of the roots. Zoosporangial and cystosoral plasmodia are indistinguishable until cleavage has started. It is thought that plasmodia produced during early infection develop into zoosporangia, while those produced later develop into resting spores. Zoospores discharged from zoosporangia may reinfect host cells developing there into zoosporangial or cystosoral plasmodia. No evidence for any sexual process was observed. The spherical zoosporangia making up a single zoosporangial sorus may be interconnected; a single discharge pore may serve to liberate zoospores from different zoosporangia. In the Plasmodiophorales the classical basis for generic distinction has been the arrangement of the resting spores in the sorus. Ligniera, because of the supposedly uncharacteristic nature of its cystosori, has been suggested as a host-variety of Sorosphaera. A comparative study of the cystosori and zoosporangia of Ligniera and Sorosphaera growing in a single host has led to the conclusion that these genera should be considered distinct.     

禾谷多粘菌( Polymyxa graminis )侵染及传毒体系的研究

在人工气候箱内,以小麦为寄 主建立了专性寄生禾谷多粘菌（Ｐｏｌｙｍｙｘａ ｇｒａｍｉｎｉｓ）的侵染体系,ｇｒａｍｉｎｉｓ能够快速大量繁殖,生活史缩短为１３￣１５ｄ。简化了单孢子堆分离以及病根表面消毒等分离纯化方法,对接种的菌源材料、寄主苗龄、温度、ｐＨ值及营养液成分等影响因素进行了测定,优化完善了Ｐ．ｇｒａｍｉｎｉｓ的砂培条件。建立了针对小麦黄花叶病毒（ｗｈｅａ４ｔ ｙｅｌｌｏｗ ｍｏｓａｉｃ ｖ     

不同形态的烟曲霉对巨噬细胞自噬水平的影响

目的探究烟曲霉静息孢子、膨胀孢子以及菌丝对巨噬细胞自噬水平的影响。方法培养烟曲霉并收获静息孢子,在沙保弱液体培养基中振荡不同时间获得膨胀孢子及菌丝。以3种形态的烟曲霉分组处理RAW264.7细胞,免疫印迹法检测LC3BⅡ蛋白的表达量,逆转录PCR检测自噬相关蛋白Atg5、Atg7、Atg12 mRNA的转录水平。观察不同形态的烟曲霉刺激GFP-LC3B-RAW264.7细胞后GFP-LC3B的表达与定位。结果膨胀的烟曲霉孢子及菌丝刺激巨噬细胞后LC3BⅡ表达水平升高;Atg5与Atg12 mRNA的转录均明显增高,Atg7转录水平无显著变化;膨胀孢子诱导LC3B呈斑点样聚集并与之共定位,烟曲霉菌丝刺激后自噬体增多。结论烟曲霉膨胀孢子与菌丝能显著提高巨噬细胞自噬水平,静息的分生孢子不能引起巨噬细胞自噬功能的应答。     

Ultrastructural examination of the host inflammatory response within gills of netpen reared chinook salmon (Oncorhynchus tshawytscha) with Microsporidial Gill Disease

The sequence of host changes following the rupture of spore-laden xenomas of the microsporidian Loma salmonae during Microsporidial Gill Disease of Salmon was deduced from ultrastructural examination of the gills of naturally infected, moribund, chinook salmon from a commercial aquaculture site. The gills contained many stages of parasite development suggesting fish were chronically exposed to the parasite. Intact xenomas were generally found beneath the endothelium in arteries and arterioles and were encapsulated by a layer of collagen containing fibroblasts sometimes joined by desmosomes. Xenoma dissolution was characterized by neutrophil infiltration and loss of the xenoma plasma membrane and encapsulation. The inflammatory responses associated with ruptured xenomas ranged from acute lesions, denoted by a marked neutrophil infiltration and vascular thrombosis, to chronic lesions with a macrophage-rich infiltrate variously accompanied by neovascularization and vascular remodelling. Dendritic-like cells and plasma cells were characteristic throughout. Basement membrane damage of the primary filament epithelium and subsequent transepithelial expulsion of spores were associated with severe inflammation. An unusual previously undescribed multifocal change, in which epithelial cells invaded deeply beyond the normal boundaries of the basement membrane, affected areas of gill filament epithelium with basement membrane damage. Some neutrophils that contained L. salmonae spores, or spore polar tube, displayed morphological changes that included irregular cell shape, cytoplasmic darkening associated with an abundance of free ribosomes, lysis of neighbouring cells, and type II nuclear clefts. Fusion of apparently intact neutrophils occurred in other areas of the lesion, where close contacts between neighbouring cells were established and in some areas plasma membrane fusion occurred. Closely associated neutrophils with intact plasma membranes were observed to contain type II nuclear clefts, abundant granules and rough endoplasmic reticulum. Other neutrophils in the lesion displayed type I nuclear pockets, which is suspected to be an early stage of apoptosis.     

广东沿海洛氏角毛藻复合群物种多样性的探究

为了澄清洛氏角毛藻复合群的物种多样性, 并明确洛氏角毛藻和并基角毛藻的种间界限, 文章以广东沿海为例, 建立了洛氏角毛藻复合群的22个单克隆培养株系, 利用光学显微镜和电子显微镜技术, 开展了基于生活史的连续形态学观察; 结合基于核糖体大亚基编码基因D1-D3区序列的分子系统学分析。结果表明: 文章支持近年研究的观点, 认为“角毛基部并行融合”不是稳定特征, 不宜继续作为并基角毛藻的标志特征; 发现洛氏角毛藻形态相似藻株聚类在2个分支上, 确认了洛氏角毛藻确实存在隐藏的物种多样性。其中一类与目前认知的洛氏角毛藻最为接近, 而另一类在角毛孔纹、休眠孢子上存在明显区别。经过对洛氏角毛藻历史文献的对比研究, 发现洛氏角毛藻的物种界定存在混乱和模糊的情况, 如休眠孢子形态, 及其初生壳面是否具有二叉状分布结构等, 均存在相互矛盾或不一致的历史报道。     

THE INLAND CHAETOCEROS (BACILLARIOPHYCEAE) SPECIES OF NORTH AMERICA1

Five taxa of Chaetoceros occur in inland waters of North America. These most commonly occur in waters with elevated total dissolved solids in arid regions of the western United States and Canada. Chaetoceros amanita Cleve-Euler is characterized by consistently forming relatively long chains of cells and having very spinose primary resting spore valves. Chaetoceros elmorei Boyer also forms long chains of cells which are connected by evident valvar processes; spores are nearly always smooth. Chaetoceros muelleri Lemm. may form short chains with processes between sibling valves, but also produces solitary cells lacking processes. Chaetoceros muelleri var. subsalsum (Lemm.)Johansen et Rushforth is similar to the nominate but never produces cells with Processes. Both of the C. muelleri varieties produce spores with smooth primary valves. Chaetoceros simplex Ostenfeld is characterized by a noncolonial habit, cells lacking processes and the production of resting spores with warty to some what spinose primary valves.