长根小奥德蘑双孢菌株与四孢菌株核相变化的比较

用双苯并咪唑（Hoechst 33258）染色法分别对长根小奥德蘑Oudemansiella radicata双孢菌株和四孢菌株的菌丝、子实体、担孢子进行染色观察,结果表明：双孢长根小奥德蘑菌丝细胞多为单核,无锁状联合;原担子中单核进行一次有丝分裂形成两个横向或纵向排列的子核,这2个子核分别进入2个担孢子中,留下无核的空担子;成熟担孢子具有一个核。四孢长根小奥德蘑菌丝细胞大多数为双核,具有锁状联合;进入原担子中的两个单倍性细胞核先发生核配,形成一个二倍性的核,再经过减数分裂形成四个染色体减半的单倍性子核,     

双孢蘑菇疣孢霉病的发病过程及病原菌的核相研究

【目的】确定有害疣孢霉的传播途径,明确双孢蘑菇受有害疣孢霉侵染后发病症状和微观形态变化,以及有害疣孢霉的核相。【方法】将有害疣孢霉喷施于培养料及覆土材料的不同深度,观察记录双孢蘑菇的发病情况;将有害疣孢霉接种于不同生长阶段的双孢蘑菇子实体,观察记录其发病情况;使用光学显微镜及扫描电镜观察双孢蘑菇子实体受有害疣孢霉侵染前后的形态变化;通过DAPI(4′,6-二脒基-2-苯基吲哚)染色的方法对有害疣孢霉核相进行观察。【结果】将有害疣孢霉接种于培养料及覆土层的不同深度得到双孢蘑菇发病率如下:覆土层表面覆土层中间覆土与培养料交界处培养料中间层;有害疣孢霉可以侵染双孢蘑菇的任意阶段,将其接种于原基直径小于3 mm子实体表面时,得到不能正常分化的"马勃状"组织;对有害疣孢霉的侵染过程进行观察得到:其孢子可粘附于双孢蘑菇表面,并萌发长出芽管,接种处双孢蘑菇表面产生褐色病斑,双孢蘑菇菌丝体发生质壁分离,最后菌丝体膨大,细胞壁变薄甚至溢裂,菌丝体内部中空;有害疣孢霉产生两种类型的分生孢子,Ⅰ类无隔膜含1个细胞核;Ⅱ类具1隔膜含2个细胞核,2个细胞核被隔膜分开;细胞核的第1次有丝分裂发生于分生孢子母细胞中;厚垣孢子由上下2个细胞构成,上胞中含有2个细胞核。下胞含1–2个细胞核。有害疣孢霉的厚垣孢子萌发可产生1–2个芽管,芽管中细胞核的数目不断变化,一般0–2个细胞核。【结论】双孢蘑菇受其侵染后发生显著的细胞学变化;我们对有害疣孢霉做遗传分析时,进行单孢分离需挑取无隔膜的分生孢子为实验材料进行遗传分析。     

土红粉盖鹅膏菌减数分裂及核相变化的观察

用双苯并咪唑（Ｈｏｅｃｈｓｔ ３３２５８）染色法对不同大小的土红粉盖鹅膏菌子０实体切取菌褶进行观察。结果表明：土红盖鹅膏菌最初形成单倍性双核原担子,单倍性双核原担子发生核配,形成二倍性单核原担子,二倍性单核原担子细胞核发生染色体复制,经减数分裂过程形成４个染色体减半的单倍性子核,这４个子核分别进入形成的４个担孢子中,留下无核的空担子;在减数分裂过程中,出现明显的土星环式细胞;在担孢子中子核又发生有     

优雅蝈螽精子形成过程中核的形态结构变化观察（英文）

【目的】螽斯精子结构复杂,具有特征性的箭头状顶体,是研究昆虫精子形成的理想材料。为了研究螽斯精子形成过程中的动态变化机制,特别是细胞核的凝集机制和箭头状顶体的发生机制,本研究对优雅蝈螽Gampsocleis gratiosa精细胞和精子的细胞核进行了观察。【方法】选择发育良好的优雅蝈螽成虫精巢为研究材料,利用透射电镜技术、普通光学显微镜和荧光显微镜技术,制作光镜切片和电镜切片进行观察。【结果】根据其形态结构变化特征,将优雅蝈螽精子形成过程中的细胞核分为4个阶段：圆形核、叶形核、柱状核和成熟阶段。我们还通过常规HE染色,结合DNA特异性荧光探针DAPI,证明了圆形核时期,精细胞内具有两个明显的球状结构,一个为细胞核,另一个是原顶体;精子成熟阶段,精子尾部排出的细胞质微滴中含有DNA。【结论】优雅蝈螽精子形成过程中,精细胞的细胞核经历了显著的形态变化,精细胞核的形态变化与细胞骨架微管相关,细胞核塑形伴随着染色质的重组。本研究为进一步阐明直翅目昆虫精子形成的分子机制奠定了基础。     

灰花纹鹅膏菌(Amanita fuliginea)子实体发育及核相观察

采用石蜡切片、压片等方法对灰花纹鹅膏菌(Amanita fuliginea)子实体发育过程进行了观察,并用核荧光染料Hoechst 33258对灰花纹鹅膏菌子实体发育过程中的核相变化进行了观察。结果表明,灰花纹鹅膏菌子实体发育是典型的半被果型发育,菌褶是子实层同时发育类型,属于同型菌髓。在子实体发育过程中,单倍的二核担子核配后形成短暂的二倍体单核担子,经过减数分裂形成四核担子,有近40%的担子中核再进行一次有丝分裂形成8核担子,担子进一步发育产生担孢子,其中,二核担孢子约占95%,单核担孢子约2.4%,三核孢子2%左右,4核担孢子约0.4%。灰花纹鹅膏菌基因组中染色体数目2n=10条。     

浙江无核柿炭疽病菌鉴定及附着胞形成过程中的核相变化

浙江无核柿炭疽病近年来在浙江淳安地区严重发生,根据形态学特征病原菌鉴定为胶孢炭疽菌ColletotrichumgloeosporioidesPenz.,在枝条病斑上的分生孢子盘通常不产生刚毛,分生孢子顶端顶部钝圆,基部平截,分生孢子盘中的孢子包埋在基质中,紧密结合在一起。分生孢子在自然寄主和人工培养条件下形态特征相似。6个柿树炭疽菌菌株的rDNAITS序列联配显示,其序列是相同的。用UPGMA方法分析ITS1-ITS2序列构建的炭疽菌系统发育树把6个柿树炭疽菌菌株和其它寄主上的胶孢炭疽菌或其有性型围小丛壳菌菌系分入同一个组,与根据形态学的鉴定结果一致。在附着胞形成过程中,用DAPI荧光染色观察到核相发生两次有丝分裂变化。第一次有丝分裂发生在分生孢子固着聚苯乙烯塑料培养皿3-4h后,随后,分生孢子中部形成一个隔膜,把它分成两个细胞;6~7h后,分生孢子发生第二次有丝分裂。分裂后,一个核通过芽管移入附着胞中。     

HSP70、PCNA、ALP和ACP在小鼠前胃癌变过程中的表达变化及意义

目的:本研究用NSEE作为诱变剂建立NIH小鼠前胃癌病变(即小鼠食管的膨大部分)模型,探讨HSP70、PCNA和ALP、ACP在前胃癌变过程中的表达及意义.方法:分别在给药后14 d、28 d、42 d、56 d、70 d、84 d分六批处死小鼠,取其前胃,采用H.E染色、免疫组化ABC法和同工酶电泳法对小鼠前胃癌变过程中细胞形态的改变、HSP70、PCNA、ALP和ACP的表达进行了跟踪研究.结果:在诱发NIH小鼠前胃癌变过程中,HSP70、PCNA、ALP和ACP的表达均呈现升高趋势,且成正相关关系.结论:食管癌中HSP70、PCNA、ALP和ACP的表达可反映食管癌变程度,尤其是ALP和PCNA在癌变早期就明显高于正常,推测其可能是食管癌的早期诊断、治疗和预后检测更为敏感的指标.     

核黄素生物合成研究 1.微量培养中核黄菌(Eremothecium ashbyii)发育过程中的形态变化

从本试验观察到,核黄菌的生长全部过程是自配子或菌丝在培养基中开始发育成营养菌丝,部分菌丝形成配子囊形成配子,部分菌丝衰老自溶。当菌丝发育最盛时,核黄素的形成是最多,衰老时培养基核黄素逐渐丰富起来。核黄菌在有空气和缺乏空气时,它们的发育是有区别的,即是在缺乏空气(表面下生长)时,菌丝是细长不形成配子和产生少量核黄素。     

宋内Ⅰ相O抗原及霍乱毒素B亚基在福氏2a痢疾菌中的表达及其免疫保护效果的观察

本文利用基因重组的方法,将宋内Ｉ相Ｏ抗原基因以及霍乱毒素Ｂ亚单位基因（ｃｔｘ－Ｂ）克隆至带链球菌的ａｓｄ基因的表达载体,然后转化至ａｓｄ－痢疾菌苗株福氏２ａＴ３２。脂多糖银染以及Ｗｅｓｔｅｒｎｂｌｏｔｔｉｎｇ实验证实以上两基因都能在宿主菌中稳定表达。动物（小白鼠）保护实验表明,该重组菌对福氏２ａ、宋内氏痢疾菌的保护效率达１００％,对霍乱弧菌的保护效率也达７０％。该菌具有稳定、无抗生素标记、多价的特点。     

禾谷镰刀菌降解毒素基因Tri101的克隆和序列分析

禾谷镰刀菌Tri101基因编码的单端孢酶烯3-O-乙酰转移酶可通过加乙酰基的形式使禾谷镰刀菌产生的单族毒素(如DON)转变为较低的毒性。本研究利用RT-PCR技术从禾谷镰刀菌0623中扩增并克隆了Tri101基因的cDNA片段,测序结果表明,Tri101基因核苷酸序列阅读框架全长1356bp(GenBank序列号:GQ907236),编码451个氨基酸的多肽,推测分子量为49.45kD,等电点为5.14。氨基酸序列同源性比对结果表明,它与Kimura报道的禾谷镰刀菌Tri101氨基酸序列同源性最高,为99.56%,与其它13种镰刀菌的Tri101氨基酸序列的同源性分别为97.91%-75.68%。系统进化树分析结果表明,Fusarium graminearium0623与Fusarium sporotrichioides属于同一进化枝且与Fusarium asiaticum有较近的亲缘关系,而与F.oxysporum、F.moniliforme、F.nygamai、F.nisikadoi和F.decemcellulare的亲缘关系较远。     

Role of hydroxycinnamic acids in the infection of maize silks by Fusarium graminearum Schwabe

In the current study, the hydroxycinnamic acids in silks of diverse maize inbred lines differing in Fusarium resistance were determined at several times after inoculation with Fusarium graminearum or sterile water as control. The main objective was to determine the possible relationship between the hydroxycinnamic acid changes in silks and ear rot resistance. Several changes in the cell-wall-bound hydroxycinnamic acid concentrations were observed after inoculation with F. graminearum, although these changes were not directly correlated with genotypic resistance to this fungus. Ester-bound ferulic acid decreased, probably due to degradation of hemicellulose by hydrolytic enzymes produced by Fusarium spp., while p-coumaric acid and diferulates showed slight increases that, in conjunction, did not result in delayed F. graminearum progression through the silks. It is important to note that the decrease of ferulic acid in the F. graminearum treatment was faster in susceptible than in resistant genotypes, suggesting a differential hemicellulose degradation in silk tissues. Therefore, the ability of the maize genotypes to slow down that process through hemicellulose structural features or xylanase inhibitors needs to be addressed in future studies.     

Pathogenicity of Fusarium graminearum Schwabe isolates from Poland towards seedlings of cereal species

Ten isolates ofFusarium graminearum Schwabe originating from diseased cereal plants and kernels were tested for pathogenicity to various cultivars of wheat, rye, triticale and oats. The isolates varied greatly in their pathogenicity to the seedlings of the species, and were most pathogenic to rye and triticale, less pathogenic to barley and wheat and least pathogenic to oats.     

Conjugation resistance to Fusarium graminearum Schwabe with multiple molecular forms of some enzymes in winter wheat

Electrophoretic spectra of multiple molecular forms of peroxidase (EC 1.11.1.7), superoxide dismutase (EC 1.15.1.1), phenol oxidase (EC 1.10.3.1), and cytochrome oxidase (EC 1.9.3.1) in seedlings of two aegilops species and eleven genotypes of bread winter wheat differing in the level of their resistance to Fusarium infection are presented. Several izoforms of peroxidase, phenol oxidase, and superoxide dismutase correlate with the level of resistance to Fusarium. Infection of plants with the pathogen enhances expressiveness of some multiple forms of enzymes. Such response to infection in less pronounced in the sensitive genotypes as compared with that in the resistant ones.     

The aerobiology of Fusarium graminearum

Current knowledge of the aerobiology of Fusarium graminearum sensu lato is based on decades of published research documenting the processes of spore discharge, atmospheric transport, and deposition in this important pathogen of cereal crops worldwide. Spores from both local and more distant sources have been shown to cause infection in susceptible cereal crops when environmental conditions are favorable. Susceptible crops may be exposed throughout a growing season to airborne spores deposited in rain events and in night-time hours through gravitational settling. Given that spores deposited on cereal florets originate from distant as well as local sources, disease risk forecasts, based currently on weather favoring local spore production during the days before peak infection (i.e., initiation of crop flowering), might be improved by placing greater emphasis on local weather directly favoring infection at and following the time of flowering. Also, considering the genetic diversity of fungal spores introduced to local agricultural fields following atmospheric transport, crop breeders should select resistant varieties based on screening against a set of fungal isolates that represent the range of virulence observed in fungal populations across a broader geographic region. An increased understanding of the aerobiology of F. graminearum contributes to the overall knowledge of plant pathogen transport in the atmosphere.     

Morphogenesis in germinating Fusarium graminearum macroconidia

Fusarium graminearum (teleomorph Gibberella zeae) is a significant pathogen of wheat and corn. F. graminearum forms multicellular macroconidia that play an important role in dissemination of the disease. The spatial pattern of morphogenesis in germinating macroconidia is described. Germ tubes preferentially emerge from the apical cells in a bipolar pattern that appears to be common to filamentous fungi. Chitin deposition occurs at two locations: the spore apices and cortical regions of macroconidial cells that subsequently produce a germ tube. The spatial pattern of morphogenesis requires the presence of functional microtubules, which may be responsible for the transport of key polarity factors to specific sites. These observations suggest that F. graminearum possesses a regulatory system that marks germ tube emergence sites. Perturbation of this system may represent an effective approach for inhibiting colonization of host plant surfaces.     

Evaluation of Fusarium head blight in barley infected by Fusarium graminearum

Fusarium head blight, which is primarily caused by Fusarium graminearum, is a devastating disease in the barley field. A real-time PCR protocol was developed to evaluate the growth of this pathogen in the host plant tissues. All four strains harbored the gene encoding ATP-BINDING CASSETTE TRANSPORTER (FgABC; FGSG_00541) as a single copy within their genomes. Our Southern blot result was identical with the genomic data for F. graminearum strain PH-1. Based on the crossing point (CP) values obtained in our TaqMan real-time PCR analysis, two standard curves describing the relationship among the CP value, FgABC copy number, and amount of fungal DNA were constructed. Chronological enumeration of fungal growth was coincided with the symptom development.     

青色荧光蛋白标记的禾谷镰孢转化子的构建

【背景】近年来玉米茎腐病在我国大部分玉米产区普遍重度发生,其中镰孢菌茎腐病不仅造成了重大的经济损失,而且镰孢菌产生的毒素给人体和动物的健康也带来严重威胁。【目的】玉米茎腐病的病原组成复杂,禾谷镰孢是其中的主要病原之一,该病原菌侵染寄主导致发病的机制急需深入研究。【方法】以pCAMBIA1300质粒为骨架,利用重叠PCR的方法构建表达青色荧光蛋白的质粒pCAMBIA1300-CFP-Kan,通过农杆菌介导的遗传转化技术,将青色荧光蛋白的编码基因整合到禾谷镰孢基因组中。【结果】经过PCR鉴定和荧光显微观察,确定获得了31株青色荧光标记的禾谷镰孢菌。【结论】侵染试验结果显示,激光共聚焦显微镜下禾谷镰孢在玉米茎秆组织中的定殖位置清晰可见,该结果为进一步研究不同镰孢菌在寄主中的定殖规律奠定了基础。     

Properties of Fusarium graminearum galactose oxidase

The kinetics and action mechanism of the galactose oxidase from Fusarium graminearum were studied. pH-optimum of the enzyme activity and stability was 7.0, the activity and stability of the galactose oxidase being decreased at any other values of pH. The enzyme is destabilized at acidic pH that is connected with protonization of its ionogenic group with pK 4.7. The temperature optimum of the galactose oxidase is 35 degrees C. When studying the enzyme thermoinactivation, it was found that at temperatures below 30 degrees C the energy of activation of denaturation was about 40 kcal/mole and at temperatures ranging from 30 to 70 degrees C - 13 kcal/mole. On the basis of the data obtained it was concluded that a low-temperature form of the galactose oxidase, possessing a higher energy of activation of denaturation, is more active than a high-temperature form. The value of Km for the enzyme in respect to galactose was 0.19 M, and the value of Vmax = 360 mumole/min per g of the preparation.