Cellulose in the cell walls of the bangiophyceae (rhodophyta)

Mechanically isolated cell walls of the conchocelis phase of Bangia fuscopurpurea yield cellulose II (regenerated cellulose) upon treatment with Schweitzer's reagent. X-ray powder analysis and thin-layer chromatography of partial hydrolyzates confirm the presence of cellulose in this extract. Gas-liquid chromatographic analysis of wall hydrolyzates indicates that xylose, mannose, galactose, and glucose are major wall constituents. The presence of cellulose in the conchocelis provides evidence that this bangiophycean life cycle phase represents a transitional form or link between the two classes of red algae, Bangiophyceae and Florideophyceae. This suggests a close affinity of the two classes of the Rhodophyta and supports the hypothesis that bangiophycean algae were precursors of the Florideophyceae.     

木霉菌原生质体的制备和再生的研究

采用正交拉丁设计对影响木霉菌原生质体制备和再生的条件进行了系统研究。结果表明：木霉菌原生质体制备受到缓冲体系、渗透压稳定剂、木霉菌菌龄、细胞壁降解酶的种类、酶解时间和再生培养基的影响，而不受木霉菌株系的影响。其中以磷酸缓冲体系和蔗糖为渗透压调节剂的降解体系为最佳，木霉菌菌龄以培养20h较好，崩溃酶对木霉菌细胞壁的降解效果好，酶解时间以4h为最佳，再生培养基以基础培养基和NaCl为渗透压调节剂为最佳。     

四种真菌基因组编码的细胞壁降解酶生物信息学分析

为了比较病原性真菌和非病原性真菌基因组编码的植物细胞壁降解酶,用BLAST(Basic Local Alignment Search tool)结合人工二次筛选的方法确定了四种真菌基因组编码的多种植物细胞壁降解酶,并用SignalP来判断细胞壁降解酶能否被分泌到细胞外.结果表明病原性真菌和非病原性真菌基因组编码的植物细胞壁降解酶在种类和数量上存在着明显的差异,其中E3(endoglucanase Ⅱ)仅由病原性真菌基因组编码,而且能够被分泌到细胞外,可能与病原性真菌对植物的致病性有着密切的关系.     

Fungal morphogenesis: cell wall construction in Mucor rouxii

An autoradiographic study revealed two different patterns of cell wall constructioni associated with two types of morphogenesis in Mucor rouxii. In hyphae, the cell wall was preferentially synthesized in the apical region; these cylindrical walls seemed to be generated by a sharply descending gradient of wall synthesis radiating from the apex. In spherical cells (germinating spores, yeast cells), wall formation occurred largely, if not entirely, in uniformly dispersed fashion over the entire cell periphery.     

丙烷脒对番茄灰霉病菌超微结构的影响

    利用电子显微技术研究了丙烷脒(propamidine)对番茄灰霉病菌(Botrytis cinerea Pers.)菌丝形态和细胞结构的影响.研究发现丙烷脒不仅影响菌丝的生长,而且引起菌丝形态和细胞结构一系列的变化.丙烷脒处理番茄灰霉病菌菌丝后,引起病菌菌丝形态和细胞结构的变化主要包括:菌丝分枝增多,并呈不规则的膨大和缢缩,细胞壁出现不规则的加厚,顶端加厚尤其严重,线粒体数目急剧增多且出现不规则的膨大现象,随着处理时间的延长,细胞出现空泡化和电子致密度增加现象.这些细胞学变化特征最终导致菌丝细胞解体死亡.     

小麦品种对条锈病低反应型抗性的组织学和超微结构研究

 采用荧光显微镜、微分干涉显微镜和电子显微镜技术 ,系统研究了非亲和组合中小麦对条锈病低反应型抗性的组织学和超微结构特征。非亲和组合分别由小麦品种牛朱特与条中 2 8号小种、杂种 4 6与条中 2 9号小种、天选 882与条中 2 9号小种组成 ,对照亲和组合由小麦品种辉县红与条中 2 9号小种组成。观察结果表明 ,小麦条锈菌在感病品种和抗病品种上发育的组织学和超微结构特征有明显差异。病菌在抗病品种上表现为菌丝生长受抑 ,菌落形成延迟或败育 ,病菌吸器母细胞和吸器数量明显减少。寄主细胞的坏死与条锈菌的发育受阻密切相关 ,免疫组合中病菌的受抑程度高于近免疫组合的。电镜观察发现 ,在抗病品种上 ,病菌胞间菌丝、吸器母细胞、吸器在细胞和亚细胞水平 ,均发生了一系列异常变化 ,其中包括原生质的电子致密度加深、液泡增多变大、菌丝细胞壁不规则增厚、细胞器排列紊乱及解体、吸器母细胞及吸器丧失其生理功能、病菌最终畸形坏死。同时发现抗病品种受病菌侵染时可迅速产生结构防卫反应 ,新形成胞壁沉积物和吸器鞘等结构 ,以阻碍病菌进一步的扩展与发育。就小麦品种与条锈菌非亲和组合中表现出的组织学和细胞学特征与小麦抗锈性表达的关系进行了讨论。     

Histology and Ultrastructure of Incompatible Combination Between Puccinia striiformis and Wheat Cultivars with Low Reaction Type Resistance

The incompatible combinations between races of Puccinia striiformis and wheat cuitivars withlow reaction type resistance were examined by means of fluorescent microscopy, differential interference con-trast microscopy and electron microscopy. The incompatible combinations consisted of wheat cultivar Niuzhuteplus CY28, Hybrid46 plus CY29 and Tianxuan882 plus CY29, while the compatible combination was wheatcultivar Huixianhong plus CY28. The observation revealed a striking difference in the fungal development andthe host responses between susceptible and resistant wheat cuitivars following infection by the pathogen. Themain histological manifestation of the pathogen development in the resistant wheat cultivars include inhibitionof hyphal growth, delay of hyphal branching and colony formation, decrease of formation of haustorial mothercells and haustoria, and occurrence of host cell necrosis. The observation by electron microscopy demonstratedthat a series of abnormal changes occurred in intercellular hyphae, haustorial mother cells and haustoria dur-ing pathogen development in the resistant wheat cultivars. The cytoplasm became more electron-dense and vac-uoles in the cytoplasm increased in number and size. The cell walls of hyphae, haustorial mother cells werethickened irregularly. The organeiles were disorderly distributed in the cytoplasm and the haustorial mothercells and haustoria lost their physiological function. In the final stage of the pathogen development, the inter-cellular hyphae, haustorial mother cells and haustoria became necrotic and collapsed. The structural defensereactions such as formation of cell wall apposition, collar and encasement of haustorium were essentially morepronounced in the infected wheat leaves of the resistant cultivars than in the susceptible one. In addition, therelationship between the host resistance expression and the histological and cytological features occurred in theincompatible combination was discussed in this paper.     

镉胁迫对巴西蘑菇镉亚细胞分布和非蛋白巯基的影响

本研究以不同浓度镉胁迫下的巴西蘑菇菌株J1（高Cd积累菌株）和J77（低Cd积累菌株）为实验材料，通过差速离心和酶联免疫法（ELISA），研究了菌丝生长、镉亚细胞分布、细胞内镉螯合相关的小分子非蛋白巯基化合物含量的变化以及小分子非蛋白巯基化合物代谢酶的活性，从细胞水平及酶学活性方面揭示了不同镉积累菌株对镉胁迫的响应机制。结果显示：随着外源添加镉浓度增加，2个菌株菌丝生长均受到抑制，出现大量气生菌丝，且J77气生菌丝多于J1； J1和J77菌丝中镉的分布规律均为细胞壁>细胞液>细胞器，表明细胞壁具有固持Cd²⁺的作用；菌株J77中谷胱甘肽硫转移酶（GST）、谷胱甘肽过氧化物酶（GSH-Px）活性均高于J1； J77和J1中植物螯合肽（PCs）和非蛋白巯基（NPT）含量变化趋势一致，表现出“低促高抑”；相关性分析显示，镉胁迫与GSH-Px活性呈正相关关系，NPT含量与PCs含量呈极显著正相关。巴西蘑菇菌丝体镉解毒机制包括细胞壁沉积和重金属分区，非蛋白巯基物质的合成，不同菌株对镉胁迫响应存在差异。     

外源H2O2处理对马铃薯块茎干腐病的控制及其机理

【目的】研究外源过氧化氢（H2O2）处理对采后马铃薯块茎干腐病的控制效果及作用机理。【方法】在离体条件下通过扫描电镜、透射电镜等方法观察分析外源H2O2对马铃薯干腐病菌(Fusarium sulphureum)生长、菌落形态及其超微结构的影响,并以陇薯3号马铃薯为试材,分别在处理前后接种F. sulphureum,研究外源H2O2对病害的治愈和预防作用。【结果】外源H2O2处理强烈抑制了F. sulphureum的菌丝生长和孢子萌发且表现出明显的浓度效应,显著增大了F. sulphureum的细胞膜透性;扫描电镜观察发现H2O2处理过的F. sulphureum菌落分布不均匀,菌丝缠绕、扭曲在一起,部分菌丝出现断裂、塌陷等现象;透射电镜进一步观察到H2O2处理过的菌丝细胞壁加厚且内部出现空腔。体内试验结果表明,外源H2O2处理对处理前后接种F. sulphureum的马铃薯块茎干腐病均具有一定控制作用。【结论】H2O2不仅对病原物具有直接的抑制作用,还能有效提高马铃薯块茎组织的抗病性,因此H2O2可以作为一种具有潜力的天然防腐剂应用于马铃薯采后病害的控制。     

杨梅共生菌Frankia的分离培养及侵染特性

采用根瘤匀浆和根瘤切片法对福建南部、中部和东北部的杨梅根瘤共生菌进行了分离,并进行菌株培养、初步鉴定及侵染特性检测。结果获得6株共生菌,菌株具有分枝状菌丝、孢囊、泡囊等典型Frankia的特征性结构,经无氮诱导有固氮活性,在BAP液体培养基中生长良好,适宜的碳源为乙酸钠、丙酸钠和丙酮酸钠,适宜的氮源为酪蛋白。5个菌株生理类群为B型,细胞壁化学组分为Ⅲ型,菌株FMr16比较特异,具有串珠状菌丝体,生理类群为A型,细胞壁组分为Ⅱ型。侵染结果表明,6个菌株可侵染杨梅、沙枣、沙棘和四川桤木,但不使木麻黄结瘤,菌丝体接种效果好于根瘤匀浆接种,菌丝体分批接种效果优于单次接种。     

江南桤木根瘤及其内生菌超微结构的研究

用光学显微镜、透射电镜和扫描电镜对江南桤木(Alnus trabeculo sa Hand—Mazz.)根瘤形态解剖特征及其内生菌的超微结构进行了观察研究。 江南桤木根瘤属于典型的枝丛状类型瘤,多年生根瘤簇直径1—5cm。电镜图象表示,成熟根瘤的内皮层细胞中存在大量菌丝与泡囊,少数感染细胞产生大量多态形的拟类菌体细胞。菌丝分枝、具有高密度电子的单层细胞壁和单层壁的横隔膜,直径0.3—0.5μm,细胞质内有明显单位膜的中间体。成熟的泡囊园形或椭圆形,表面比较光滑,细胞壁不完整,直径为2—4μm。内生菌的这些不同发育形态与它们在共生固氮中的作用,本文也作了讨论。     

Antifungal Activity of Chitosan on Fusarium sulphureum in Relation to Dry Rot of Potato Tuber

The antifungal activity of chitosan on Fusarium sulphureum in relation to the inhibitory effect on dry rot of potato tuber was investigated. The results showed spore germination and mycelial growth of F. sulphureum were inhibited by chitosan treatment and the inhibitory effect was highly correlated with chitosan concentration used in this study. Morphological changes such as intertwisting hyphal, distortion, and swelling with excessive branching were observed by scanning electron microscopy （SEM） observation. Transmission electron microscopy （TEM） observation further indicated the ultrastructural alterations of hyphae. These changes included abnormal distribution of cytoplasma, non-membraneous inclusion bodies assembling in cytoplasm, considerable thickening of the hyphal cellular walls, and very frequent septation with malformed septa. Application of chitosan at higher concentration caused serious damage to fungal hyphae, including cellular membrane disorganisation, cell wall disruption, and breaking of inner cytoplast. New hyphae （daughter hyphae） inside the collapsed hyphal cells was often detected in the cytoplasm of chitosan-treated hyphae. In vivo tests showed that chitosan treatment at 0.5 or 1% effectively controlled the dry rot of potato tuber inoculated with a spore suspension ofF. sulphureum. However, the chitosan treatment at 1% caused phytotoxicity to potato tuber. This study suggests that the use of chitosan could be a promising handling as a natural fungicide to partially substitute for the synthetic fungicides in potato tuber.     

Infection Behaviour of Melampsora larici-populina on the Leaf Surface of Populus purdomii

Behaviours of urediospore germtube in Melampsora larici-populina on the leaf surface of Populus purdomii were studied by light microscope,scanning electron microscope (SEM),transmission electron microscope (TEM),and fluorescence microscope.Crab-like fusion cells on leaf surface,intercellular hyphal cells in leaf tissues,as well as nucleus states,were observed and counted up in this study.Under unsaturated humidity,32％ of germinated tubes fused into a distinguishable swollen crab-shaped cell at the merging site,and 10.5％ of observed crab-like cells had more than three nuclei.Wedge-shaped mycelia developed and then penetrated the leaf surface directly,or indirectly through stomata.Tips of germtube passed through the intercellular cells of poplar leaves directly were found in TEM.Aniline blue dyeing also showed that the infecting hyphae could invade into the cuticle and epidemic cell wall directly.For the case of infection through stomata,there were two different situations.Short branches and wedge hyphae usually penetrated the leaf surface via opened stomata,whereas,some germtube branches and wedge hyphae penetrated leaves through the guard cell walls or stoma lips.In the latter case,the stomata were always closed.The samples from wild forestlands had the same fused cells and wedge hyphae,but the occurrence rate was much higher than that in the chamber.Even under the saturated air humidity,germtubes could roll back and formed fusion structure,or merged together with their tips.The fusion cells might centralize the plasma of merged germtubes and have a strong survival capacity to protect germtubes from dying under arid circumstances,and provide a chance of genetic variation as well.     

立枯丝核菌拮抗青霉菌筛选及抑菌机制初步研究

为筛选具有生防作用的青霉菌菌株并探索其作用机制,采用平板稀释法和对峙培养法,从宁夏回族自治区境内不同作物土壤中分离到18株青霉菌菌株,筛选到1株具有高效拮抗立枯丝核菌的生防菌P19,对立枯丝核菌丝生长抑制率达58.5%。利用光学显微镜观察P19对立枯丝核菌菌丝形态的影响,发现菌丝壁出现弯曲和畸形,原生质体凝结和溶解,菌丝被溶解等现象。结果表明,P19对立枯丝核菌具有明显的抑制作用,其生长对立枯丝核菌造成空间和营养方面的竞争,也可能是P19所含有的抗菌物质破坏立枯丝核菌的细胞壁,进而溶解菌丝内的原生质体,使立枯丝核菌的生长受到限制。     

虎头兰菌根中酸性磷酸酶的定位及活性变化

为揭示虎头兰与共生的菌根真菌间的相互作用,应用细胞化学的方法定位研究了虎头兰菌根中入侵的菌丝被消化过程的酸性磷酸酶(AcPase)活性变化,结果表明:AcPase反应出现在虎头兰菌根皮层细胞的细胞壁和膜系统上.在菌根真菌侵入虎头兰根部细胞,入侵菌丝被溶酶体包围并消解,直到被消解成空腔或彻底解体,最后溶酶体也随之消失的过程中,虎头兰细胞内的细胞壁、胞间隙、细胞膜、胞间连丝等处AcPase的活性呈现由高到低,最后完全消失的变化;在溶酶体和菌丝细胞上AcPase的活性则表现出由低到高,然后又逐渐降低直至完全消失.被菌丝侵入的虎头兰细胞发生了一系列的变化:细胞壁严重扭曲变形,线粒体、叶绿体及大量小液泡等细胞器消失,细胞核变形逐渐降解直至消失;溶酶体大量出现并包围和消解菌丝细胞,菌丝细胞被彻底消化,溶酶体消失;细胞内又重新出现线粒体、液泡、更新核等细胞器,更新核还可不断的进行有丝分裂.      

核桃仁霉烂病病原菌鉴定及生物学特性研究

对核桃仁霉烂病病原菌进行了分离鉴定,并对其生物学特性进行了研究。结果表明,核桃仁霉烂病病原为立枯丝核菌。病原菌最适生长条件为:25~30℃,pH值5~9,PDA培养基,连续光照。核桃应储存在低温、干燥条件下,以抑制病原菌生长,减少病害的发生。     

硼对不同甘蓝型油菜品种悬浮细胞生长及细胞壁组成的影响

利用不同硼效率甘蓝型油菜（Brassica napus)品种下胚轴诱导的悬浮细胞，研究硼对细胞生长和细胞壁组成的影响及不同硼效率油菜品种细胞壁组成的差异。结果表明：在0－0.5mg/L的硼含量范围内，细胞的生长速度随硼含量的增加而增加。缺硼显著提高细胞壁提取率和SDS（十二烷基碘酸钠）提取物含量，降低纤维素和半纤维素含量，特别对硼低效品种影响更大。硼高效品种悬浮细胞细胞壁提取率和半纤维素含量低于低效品种，碱溶性果胶含量高于低效品种，螯合剂可溶性果胶和纤维素含量品种间差异不显著。     

亚麻快速生长期细胞壁形成相关基因的表达分析

【目的】亚麻在快速生长期其韧皮纤维细胞发育在SP(the snap point)点上下端分别经历细胞伸长和次生细胞壁加厚2个不重叠时期。研究亚麻快速生长期不同组织、不同时期、不同器官中与细胞壁形成相关的β-半乳糖苷酶(Lu BGALs)、纤维素合酶(Lu CESAs)等家族基因的表达谱,探讨快速生长期亚麻韧皮纤维细胞细胞壁的发育模式,为改善亚麻纤维产量提供理论依据。【方法】以生长45 d的亚麻根、茎韧皮纤维、叶为材料,用透射电镜观察并测量茎韧皮纤维细胞细胞壁结构和厚度,采用实时荧光定量(q RT-PCR)方法,研究亚麻快速生长期Lu BGALs和Lu CESAs等细胞壁形成相关的基因在亚麻韧皮纤维不同阶段的表达特点。【结果】在SP点上部TOP端纤维细胞细胞壁薄,约110 nm;紧邻SP点茎中部的MID区(约500 nm)和茎下部的BOT区(约650 nm),细胞壁厚度明显增厚,细胞壁质地均一,没有明显的分层现象,说明SP点中部和下部韧皮纤维细胞细胞壁已经开始加厚但还未进入次生壁加厚阶段,与TOP明显不同。亚麻Lu BGAL1在TOP区的表达显著低于MID区和BOT区,表明其主要参与纤维细胞细胞壁加厚过程。而Lu BGAL3、Lu BGAL6、Lu BGAL9在TOP区表达最高,MID区次之,表明此类基因主要参与亚麻韧皮细胞伸长和细胞壁重建过程。Lu BGAL5在幼嫩的TOP区表达量高,在亚麻茎较为成熟的MID区较低,说明Lu BGAL5在细胞壁形成过程中起作用。其他BGALs基因的表达量均较低。在亚麻茎幼嫩的TOP区纤维细胞中,亚麻纤维素合酶基因Lu CESA1、Lu CESA3、Lu CESA7、Lu CESA8、Lu CESA9和Lu CESA10都检测出较高的表达量,且明显高于其在MID区和BOT区的表达。其中Lu CESA3和Lu CESA10在MID区的表达显著低于BOT区,其他几个CESAs基因在MID和BOT的表达并无明显差异。结合这些基因在亚麻快速生长期不同器官中的表达模式,结果说明,亚麻中6个CESA(Lu CESA1、Lu CESA3、Lu CESA7、Lu CESA8、Lu CESA9和Lu CESA10)主要促进亚麻韧皮纤维细胞的伸长。Lu Su Sy在幼茎韧皮纤维细胞中表达量高,表明亚麻茎伸长和加粗需要大量能量。Lu XTH4在亚麻细胞壁发育过程中发挥作用。【结论】快速生长期亚麻茎韧皮纤维细胞细胞壁没有次生加厚过程;Lu BGAL3、Lu BGAL5、Lu BGAL6、Lu BGAL9、Lu CESA1、Lu CESA3、Lu CESA9和Lu CESA10在亚麻细胞壁细胞伸长过程中起作用;Lu BGAL1主要促进亚麻细胞壁加厚过程;Lu Su Sy和Lu XTH4在亚麻细胞壁发育中发挥作用。     

Mutagenic and recombinogenic activities of the food additive furylfuramide in eurkaryotes

The mutagenic and recombinogenic activities of furylfuramide, an antimicrobial food additive, were tested in a two-component heterokaryon of Neurospora crassa and a diploid strain of Saccharomyces cerevisiae, respectively. The results show that furylfuramide is genetically active in both eukaryotic organisms; it induces mutations in Neurospora crassa and mitotic crossing over in Saccharomyces cerevisiae.     

玉米抗腐霉菌茎腐病超微结构的研究

超微结构观察表明,抗茎腐病玉米品种冀丰５８号幼苗根组织被肿吓腐霉菌侵染后,细胞迅速出现严重的质壁分离,质膜消失、各种细胞器紊乱破碎。侵入根组织的肿囊腐霉菌数量少,幼嫩且形态异常,菌丝外周或整个菌丝中出理一些电子致密物质,可能与发生过敏性坏死反应有关。感颈腐病品种掖单１３号幼苗根组织被侵染细胞的壁完整,但细胞质凝聚或细胞器发生解体。根组织内在大量胞间及胞内生长菌丝,菌丝较成熟、粗壮,含大量的泡囊及线粒体,结构正常。氟乐灵浸种后再接种肿囊腐霉,玉米根系的超微结构较单独接种肿囊霉处理有明显的不同,抗病品种的ＨＲ反应更加剧烈、迅速,甚至感病品种也被诱导产生了ＨＲ反应,尤其是被侵染细胞及其临近细胞有大量近球形的电子致密物质沉积,该物质可能与抗性有关。这些电子致密物质在抗感品种上均有出现,在单独接种肿囊腐霉处理中出现很少。