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1.
报道枝孢菌属Cladosporium Link二新种:马兜铃枝孢 C. aristolochiae H. Zhang etZ. Y. Zhang sp nov.寄生在马兜铃科Aristolochiaccae 的南川马兜铃.Aristolochiakwargsiensis Chun et How ex C.F. Liang叶上,结香枝孢 Cladosporium edgeworthiae H.Zhang,et Z. Y.Zhang sp nov.寄生在瑞香科Thymelacaccac的结香Edgeworthiachrysantha Lindl.叶上。枝孢菌属真菌在马兜铃科是首次报道,瑞香科上的荛花异孢 Heterosporium wikstro—emiae Sawada(裸名),其分生孢子圆柱形,0-3个隔膜,表面粗糙,14~44×5~6μm,比本种大而宽,易于区别。文中为新种提供了拉丁文简介并附图。模式标本保藏于云南农业大学真菌标本室(MHYAU)。  相似文献   

2.
采用分室培养法,在同一宿主植物生长的土壤中设含有0、5、25、50mg/kg4个不同浓度重金属镉的菌丝生长室(用30μm尼龙网与根系隔开)以期建立在宿主植物生长状况完全相同的条件下研究环境因素对AM真菌直接影响的新方法,并在此基础上探讨不同浓度的重金属镉对丛枝菌根真菌Glomus mosseae(BEG167)生长的直接影响。结果表明,与不施加镉的处理相比,土壤中施加低浓度镉(5mg/kg)刺激了G.mosseae的生长,其菌丝总长度最大;高浓度镉(大于25mg/kg)抑制了G.mosseae的生长,其菌丝总长度较小。AM真菌的代谢活性与土壤镉浓度的关系也表现出与菌丝生物量相同的规律。以上结果表明:G.mosseae在镉污染环境中有应激反应的特征,即:当G.mosseae受到轻微毒害时,为了适应其生存条件的改变而不断增加其代谢活性和生长量来降低镉的毒害。此外,本方法用于研究宿主植物生长状况相同的条件下,重金属毒害或其他环境因素对AM真菌生长代谢的直接影响是可行的。  相似文献   

3.
从三尖杉 ,南方红豆杉及香榧中分离出 1 72株内生真菌 ,对其进行抗菌活性检测 ,结果表明共 90株内生真菌对一种或多种植物病原真菌 ,如红色面孢霉 (Neurosporasp .) ,木霉 (Trichodermasp .) ,镰刀菌 (Fusariumsp .)等有抑制作用 ,来自三尖杉、南方红豆杉和香榧的抗菌活性菌株比例分别为 40 %,54.2 %及 57.1 %。其中平板抑菌圈直径大于1 5mm的高抗菌株有 3 5株。按Ainsworth等鉴定系统和方  相似文献   

4.
黑曲霉诱变株Aspergillus niger T21糖化酶产量提高的分子基础   总被引:6,自引:2,他引:4  
黑曲霉Aspergillus niger T21是以A.niger AS3.795为出发株经诱变获得的糖化酶高产菌株,产量比原株提高10~17倍.Northern分析知T21的糖化酶mRNA含量约为AS3. 795的20倍,表明糖化酶基因(glaA)转录水平的提高是糖化酶产量提高的主要原因.以编码葡糖苷酸酶(GUS)的E.coli uidA为报告基因,分别与T21和AS3.795的glaA 5′调控区融合后,引入A.niger,根据转化子GUS酶活性测定结果,T21glaA 5′调控区的启动子活性是AS3.795相应启动子活性的3倍多,提示cis调控的改变是T21glaA转录水平提高的重要原因之一,但trans调控的改变是T21glaA转录水平提高的更重要的原因. 作为trans调控研究的第1步,进行了T21glaA 5′调控区的功能分析,结果表明,ATG上游-408 ~-513间的约100 bp区域与 glaA基因高水平表达相关.  相似文献   

5.
对毛白杨(Populus tomentosa Carr.)叶围煤污菌(sooty moulds)群落组成及演替进行了探罚,分析了叶面营养物及其变化。 结果表明,叶面真菌的分离物密度随叶片的衰老而增加。对毛白杨叶面真菌分离鉴定,属于煤污菌有8种真菌:链格孢(Alternaria alternata),芽枝状枝孢(Cladosporium cladosporioides),球孢枝孢(Coladosporium sphaerospermum),尖孢枝孢(Cladosporium oxysporum),出芽短梗霉(Aurecobasidium pullulans),棕黑腐质霉(Humtco'a tuscoatra),伏克盾壳霉(Coniothyrixm fuckelii)和直立枝顶孢(Acremoniumstrictum)。不同生长期叶面真菌群落组成及优势种不同,叶面出现黑霉层后,以3种煤污菌为优势种即出芽短梗霉、链格孢和芽枝状枝孢。不同的菌表现一定的演替模式,定殖及达到峰值的时间不同。毛白杨叶面含有多种营养物,其含量及组分随生长期不同而异.与叶面真菌分离物密度呈显著性相关。此外,对蚜虫的发生、叶面营养物含量、煤污菌三者的关系进行了讨论。  相似文献   

6.
过量铜对4种外生菌根真菌的生长、碳氮和铜积累的影响   总被引:13,自引:0,他引:13  
为了了解外生菌根真菌在过量铜胁迫下的生长和物质积累特点,揭示外生菌根真菌对过量铜胁迫的抵抗能力,研究了四种外生菌根真菌—美味牛肝菌(Boletus edulis)、铆钉菇(Gomphidius viscidus)、厚环乳牛肝菌(Suillus grevillei)和红绒盖牛肝(Xerocomus chrysenteron)在过量铜胁迫条件下菌丝中铜积累量、菌丝生长特性以及碳氮积累速率。四种测试菌种菌丝中的铜积累量,随营养液中铜浓度的增加而增加,在46mg/L铜培养基下生长15d,四种菌种菌丝内铜浓度分别是对照的40~60倍。B.edulis和X.chrysenteron菌丝中铜浓度与培养基中铜浓度呈直线相关,S.grevilleiG.viscidus为指数相关。菌丝在铜胁迫下依然呈S曲线增长,但初始生长推迟,指数增长期比对照晚1~2d。菌丝生物量和碳氮积累随铜浓度增加而显著降低。综合所有试验结果显示,四种测试菌种对过量铜的抗性强度为:B.edulis>G.viscidus>S.grevillei>X.chrysenteron。  相似文献   

7.
丝状真菌表达分泌系统中受体菌的构建   总被引:8,自引:0,他引:8  
黑曲霉糖化酶高产菌株T21经紫外诱变后, 通过酪蛋白平板和蛋白酶活性测定筛选出胞外酸性蛋白酶活力仅为原株076%的菌株A.nigerT21-201,其生长特性和产糖化酶活力与原株基本一致。利用原生质体PEG法将含有报告基因vhb的表达分泌质粒Pgt10-vhb通过与选择标记质粒的共转化导入此蛋白酶部分缺陷株及其原株T21,检测在蛋白酶缺陷株Aspergillus niger T21-201 和原株T21中VHb的分泌表达,结果表明在A.nigerT21-201中VHb表达水平显著高于原株,但Northern blot却显示在两菌株中vnb基因的转录水平近似,由此证明酸性蛋白酶缺陷对保护外源蛋白产生了显著效果。   相似文献   

8.
【目的】构建用于比较黄曲霉(Aspergillus flavus,A. flavus)菌株之间致病力差异的小鼠感染模型,并利用该模型评价真菌病毒AfPV1对宿主A. flavus致病力的影响。【方法】用不同浓度环磷酰胺腹腔注射Institute of Cancer Research (ICR)小鼠,根据白细胞的数量判断小鼠免疫抑制程度;通过滴鼻和尾静脉两种感染方法接种不同浓度的A. flavus孢子量,统计14 d以内小鼠的死亡率,确定A. flavus最佳的孢子接种量;通过小鼠组织的菌落负荷量以及肺部组织的病理观察,确定A. flavus感染是否成功;最后利用该小鼠模型评价真菌病毒AfPV1对寄主A. flavus致病力的影响。【结果】腹腔注射环磷酰胺的浓度为250 mg/kg时,能够达到免疫抑制水平;小鼠组织真菌负荷和病理组织切片观察显示A. flavus成功感染接种的ICR小鼠组织;在滴鼻接种模型中,A. flavus的孢子接种量为40μL(1×106CFU/mL)时比较合适评价A. flavus菌株之间的差异;在尾静脉接种的模型中,A. flavus的孢子...  相似文献   

9.
长白山地区真菌降解木质素的研究   总被引:9,自引:0,他引:9  
王地  刘期松 《微生物学报》1990,30(4):296-304
采用Bavendamn氏反应,漆酶(Laccase)和α-酪氨酸酶反应(α-tyrosinase reacrion)呼吸率,紫外分光光度法和扫描电镜等方法,对来自长白山地区的五株真菌进行了定性、定量测定。结果表明,长白山地区存在木质素分解菌,它们分属于曲霉属(Aspergillus)、木霉属(Trtchoderma)及毛霉属(Mucor)。它们均能不同程度地降解小叶杨(Populus simonti)、龙爪柳(Salix matsydana F. fortuosa)、家榆(Ulmus pumila)、山毛桃(Persian davidiana)的碱性水溶木质素,游离木质素及细胞回复木质素。降解主要发生在第8天以后,在第12-14天时趋于稳定,其木质素的剩余量在44—74%,它们参与木质素降解的酶不同于已报道过的白腐菌的酶。  相似文献   

10.
已报道的EMSA和Footprinting试验表明黑曲霉Aspergillus niger T21糖化酶基因glaA启动子区−489~−414 bp及−390~−345 bp (分别简称为DC, PC)是与蛋白粗提液中同一蛋白因子结合, 并均含有CCAAT五核苷酸的序列. 对DC, PC在糖化酶表达调控中的作用进行了分析. 用CGTAA取代CCAAT, 获得突变体DCm, PCm, 两者均丧失体外结合蛋白因子的能力. 突变体的体内分析结果显示, DC和PC中任何一个发生突变或改变DC, PC在原启动子中的相对方向, 则启动子的活性下降到基础表达水平. 将多拷贝串联后的DC引入A. niger T21glaA启动子原位, 则内源糖化酶的表达和由该启动子引导的外源uidA基因的表达均发生下降, 但由构巢曲霉3-磷酸甘油醛脱氢酶启动子PgpdA引导的uidA的表达不受影响, 而且EMSA结果表明不等DC拷贝的A. niger转化子中DNA结合蛋白的含量没有明显变化, 表明多拷贝DC的引入引起了调控蛋白的滴定效应. 从A. niger T21cDNA中克隆到AngHapC基因, 将AngHapC基因引入上述含多拷贝DC而糖化酶低表达的A. niger菌株, AngHapC基因的表达使糖化酶的表达量得到明显回升. 上述结果表明, DC和PC中CCAAT五核苷酸序列为蛋白因子结合所必需, 而且两者必须同时与调控蛋白结合才能发挥促进转录的作用, AngHapC为与DC区域结合的正调节蛋白.  相似文献   

11.
The preparation of hair for the determination of elements is a critical component of the analysis procedure. Open-beaker, closedvessel microwave, and flowthrough microwave digestion are methods that have been used for sample preparation and are discussed. A new digestion method for use with inductively coupled plasma-mass spectrometry (ICP-MS) has been developed. The method uses 0.2 g of hair and 3 mL of concentrated nitric acid in an atmospheric pressurelow-temperature microwave digestion (APLTMD) system. This preparation method is useful in handling a large numbers of samples per day and may be adapted to hair sample weights ranging from 0.08 to 0.3 g. After digestion, samples are analyzed by ICP-MS to determine the concentration of Li, Be, B, Na, Mg, Al, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, As, Se, Rb, Sr, Zr, Mo, Pd, Ag, Cd, Sn, Sb, I, Cs, Ba, Pt, Au, Hg, Tl, Pb, Bi, Th, and U. Benefits of the APLTMD include reduced contamination and sample handling, and increased precision, reliability, and sample throughput.  相似文献   

12.
杨超  佐佐木均 《昆虫学报》2019,62(10):1212-1227
【目的】利用日本北海道虻类评估和验证外生殖器在分类学上的意义。【方法】将虻类成虫标本浸渍在生理盐水中并置于双目显微镜下通过针和镊子在培养皿中进行解剖并绘图,观察第9背板、第10背板、尾叶、第8腹板、受精囊、受精囊管及生殖叉器的形态特征。【结果】在日本北海道共记录了虻科(Tabanidae) 3亚科7属38种。我们观察并描述了3亚科其中的6属24种的雌性外生殖器的主要特征。亚科之间存在明显差异;然而在一般情况下属之间很难建立一种方法来确定共同点;种之间只有在斑虻属Chrysops中有相似之处,其他属中则比较多样化。因此,亚科鉴定根据第9背板、第8腹板及受精囊足以进行区分,属及种鉴定需要结合第9背板、第10背板、尾叶、第8腹板、受精囊、受精囊管及生殖叉器各自的特征组合在一起才能区分开来。我们也制作了虻类外生殖器的检索表。【结论】和许多其他昆虫一样,外生殖器是虻科的重要分类特征,对于促进分类学和系统学的发展具有重要意义。本研究首次对分布在日本北海道的虻科雌性外生殖器进行了系统研究。  相似文献   

13.
 A data matrix of 143 morphological and chemical characters for 142 genera of euasterids according to the APG system was compiled and complemented with rbcL and ndhF sequences for most of the genera. The data were subjected to parsimony analysis and support was assessed by bootstrapping. Strict consensus trees from analyses of morphology alone and morphology + rbcL + ndhF are presented. The morphological data recover several groups supported by molecular data but at the level of orders and above relationships are only superficially in agreement with molecular studies. The analyses provide support for monophyly of Gentianales, Aquifoliales, Apiales, Asterales, and Dipsacales. All data indicate that Adoxaceae are closely related to Dipsacales and hence they should be included in that order. The trees were used to assess some possible morphological synapomorphies for euasterids I and II and for the orders of the APG system. Euasterids I are generally characterised by opposite leaves, entire leaf margins, hypogynous flowers, “early sympetaly” with a ring-shaped corolla primordium, fusion of stamen filaments with the corolla tube, and capsular fruits. Euasterids II often have alternate leaves, serrate-dentate leaf margins, epigynous flowers, “late sympetaly” with distinct petal primordia, free stamen filaments, and indehiscent fruits. It is unclear which of these characters represent synapomorphies and symplesiomorphies for the two groups, respectively, and there are numerous expections to be interpreted as reversals and parallelisms. Received August 28, 2000 Accepted August 7, 2001  相似文献   

14.
Targeted genetic manipulation using homologous recombination is the method of choice for functional genomic analysis to obtain a detailed view of gene function and phenotype(s). The development of mutant strains with targeted gene deletions, targeted mutations, complemented gene function, and/or tagged genes provides powerful strategies to address gene function, particularly if these genetic manipulations can be efficiently targeted to the gene locus of interest using integration mediated by double cross over homologous recombination.Due to very high rates of nonhomologous recombination, functional genomic analysis of Toxoplasma gondii has been previously limited by the absence of efficient methods for targeting gene deletions and gene replacements to specific genetic loci. Recently, we abolished the major pathway of nonhomologous recombination in type I and type II strains of T. gondii by deleting the gene encoding the KU80 protein1,2. The Δku80 strains behave normally during tachyzoite (acute) and bradyzoite (chronic) stages in vitro and in vivo and exhibit essentially a 100% frequency of homologous recombination. The Δku80 strains make functional genomic studies feasible on the single gene as well as on the genome scale1-4.Here, we report methods for using type I and type II Δku80Δhxgprt strains to advance gene targeting approaches in T. gondii. We outline efficient methods for generating gene deletions, gene replacements, and tagged genes by targeted insertion or deletion of the hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) selectable marker. The described gene targeting protocol can be used in a variety of ways in Δku80 strains to advance functional analysis of the parasite genome and to develop single strains that carry multiple targeted genetic manipulations. The application of this genetic method and subsequent phenotypic assays will reveal fundamental and unique aspects of the biology of T. gondii and related significant human pathogens that cause malaria (Plasmodium sp.) and cryptosporidiosis (Cryptosporidium).  相似文献   

15.
Deterioration in the ability to perform "Activities of daily living" (ADL) is an early sign of Alzheimer's disease (AD). Preclinical behavioural screening of possible treatments for AD currently largely focuses on cognitive testing, which frequently demands expensive equipment and lots of experimenter time. However, human episodic memory (the most severely affected aspect of memory in AD) is different to rodent memory, which seems to be largely non-episodic. Therefore the present ways of screening for new AD treatments for AD in rodents are intrinsically unlikely to succeed. A new approach to preclinical screening would be to characterise the ADL of mice. Fortuitously, several such assays have recently been developed at Oxford, and here the three most sensitive and well-characterised are presented. Burrowing was first developed in Oxford. It evolved from a need to develop a mouse hoarding paradigm. Most published rodent hoarding paradigms required a distant food source to be linked to the home cage by a connecting passage. This would involve modifying the home cage as well as making a mouse-proof connecting passage and food source. So it was considered whether it would be possible to put the food source inside the cage. It was found that if a container was placed on the floor it was emptied by the next morning., The food pellets were, however, simply deposited in a heap at the container entrance, rather than placed in a discrete place away from the container, as might be expected if the mice were truly hoarding them. Close inspection showed that the mice were performing digging ("burrowing") movements, not carrying the pellets in their mouths to a selected place as they would if truly hoarding them. Food pellets are not an essential substrate for burrowing; mice will empty tubes filled with sand, gravel, even soiled bedding from their own cage. Moreover, they will empty a full tube even if an empty one is placed next to it. Several nesting protocols exist in the literature. The present Oxford one simplifies the procedure and has a well-defined scoring system for nest quality. A hoarding paradigm was later developed in which the mice, rather than hoarding back to the real home cage, were adapted to living in the "home base" of a hoarding apparatus. This home base was connected to a tube made of wire mesh, the distal end of which contained the food source. This arrangement proved to yield good hoarding behaviour, as long as the mice were adapted to living in the "home base" during the day and only allowed to enter the hoarding tube at night.  相似文献   

16.
We have created a novel high-throughput imaging system for the analysis of behavior in 7-day-old zebrafish larvae in multi-lane plates. This system measures spontaneous behaviors and the response to an aversive stimulus, which is shown to the larvae via a PowerPoint presentation. The recorded images are analyzed with an ImageJ macro, which automatically splits the color channels, subtracts the background, and applies a threshold to identify individual larvae placement in the lanes. We can then import the coordinates into an Excel sheet to quantify swim speed, preference for edge or side of the lane, resting behavior, thigmotaxis, distance between larvae, and avoidance behavior. Subtle changes in behavior are easily detected using our system, making it useful for behavioral analyses after exposure to environmental toxicants or pharmaceuticals.  相似文献   

17.
目前,白血病复发是患者死亡的主要原因之一。肿瘤细胞和微环境的相互作用,以及隐匿在骨髓中的肿瘤干细胞,促进了白血病的复发和向淋巴组织的转移,因此白血病的治疗、转移和复发问题受到广泛关注。外泌体是由绝大多数细胞分泌的双层脂质膜囊泡,可以调控细胞间的交流和信息传递。在白血病细胞、基质细胞和内皮细胞之间的相互联系中都涉及到外泌体,白血病细胞来源的外泌体存在于白血病患者的血浆中,能把其携带的白血病相关抗原及微小RNA呈递给靶细胞,促进白血病肿瘤细胞的增殖,有助于肿瘤细胞实现免疫逃避,保护白血病细胞抵抗化疗药物导致的细胞毒性作用,促进血管生成及肿瘤细胞的迁移。因此,外泌体与白血病的转移、治疗及预后密切相关,可以用来检测和监测白血病的进展。本文综述了外泌体的来源、形成与分泌机制,以及外泌体在白血病发生前、发展中、预后和免疫治疗中所扮演的重要角色。  相似文献   

18.
The cellular factors involved in mRNA degradation and translation repression can aggregate into cytoplasmic domains known as GW bodies or mRNA processing bodies (P-bodies). However, current understanding of P-bodies, especially the regulatory aspect, remains relatively fragmentary. To provide a framework for studying the mechanisms and regulation of P-body formation, maintenance, and disassembly, we compiled a list of P-body proteins found in various species and further grouped both reported and predicted human P-body proteins according to their functions. By analyzing protein-protein interactions of human P-body components, we found that many P-body proteins form complex interaction networks with each other and with other cellular proteins that are not recognized as P-body components. The observation suggests that these other cellular proteins may play important roles in regulating P-body dynamics and functions. We further used siRNA-mediated gene knockdown and immunofluorescence microscopy to demonstrate the validity of our in silico analyses. Our combined approach identifies new P-body components and suggests that protein ubiquitination and protein phosphorylation involving 14-3-3 proteins may play critical roles for post-translational modifications of P-body components in regulating P-body dynamics. Our analyses provide not only a global view of human P-body components and their physical interactions but also a wealth of hypotheses to help guide future research on the regulation and function of human P-bodies.  相似文献   

19.
ABSTRACT. Concentration and composition of ciliate protozoa in the families Ophryoscolecidae and Isotrichidae were determined in rumen contents of domestic sheep ( Ovis ammon aries ) from Cyprus. A total of five genera of Ophryoscolecidae were identified, Metadinium, Enoploplastron, Polyplastron, Epidinium , and Ophryoscolex , which included six species: Metadinium affine, Enoploplastron triloricatum, Polyplastron multivesiculatum, Epidinium ecaudatum, Epidinium graini, and Ophryoscolex purkynjei. Eight separate forms of Epidinium were identified ( E. ecaudatum f. ecaudatum, E, e. f. caudatum, E. e. f. bicaudatum, E. e. f. tricaudatum, E. e. f. quadricaudatum, E. graini f. graini, E. g. f. caudatricoronatum , and E. g. f. caudaquadricoronatum ), along with five forms of Ophryoscolex purkynjei (O. p. f. purkynjei, O. p. f. bifidobicinctus, O. p. f. bifidoquadricinctus, O. p. f. bicoronatus, O. p. f. tricoronatus , and O. p. f. quadricoronatus). Three species of Isotrichidae were observed, Isotricha intestinalis, I. prostoma , and Dasytricha ruminantium. This study reports new host records for three forms of Epidinium graini and Ophryoscolex purkynjei f. bifidobicinctus. The rumen fauna in the family Ophryoscolecidae from Cypriote domestic sheep appear to have limited diversity compared to those from Turkish and Far Eastern (Chinese/Japanese) sheep, while they are more diverse than those found in Western European (Scottish) and North American (Canadian/Alaskan) sheep.  相似文献   

20.
Amylopathy is a term that describes abnormal synthesis and accumulation of amyloid beta (Aβ) in tissues with time. Aβ is a hallmark of Alzheimer''s disease (AD) and is found in Lewy body dementia, inclusion body myositis and cerebral amyloid angiopathy 1-4. Amylopathies progressively develop with time. For this reason simple organisms with short lifespans may help to elucidate molecular aspects of these conditions. Here, we describe experimental protocols to study Aβ-mediated neurodegeneration using the worm Caenorhabditis elegans. Thus, we construct transgenic worms by injecting DNA encoding human Aβ42 into the syncytial gonads of adult hermaphrodites. Transformant lines are stabilized by a mutagenesis-induced integration. Nematodes are age synchronized by collecting and seeding their eggs. The function of neurons expressing Aβ42 is tested in opportune behavioral assays (chemotaxis assays). Primary neuronal cultures obtained from embryos are used to complement behavioral data and to test the neuroprotective effects of anti-apoptotic compounds.  相似文献   

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