北京和安徽的水生丝孢菌

本文报道了北京、安徽部分地区水生丝孢菌中国新纪录16属23种,它们是缩翼孢Atatosporh constricta,弯水线孢 Anguillospora curvula隐水线孢A．Furtiva, 大水线孢A．Gigantca,透明毛虫孢 Camposporium pellucidum, 长臂水棒孢 Clavatospora longibrat-hiata, 水生疣钉孢Heliscus submersus,心球放射孢 Lemonniera centrosphaera, 角放射孢L．Cornuta, 线放射孢 L．Filifarmis,舟新月孢 Lunulospora eymbiformis,角基刺孢 Myco-centrospora angulata,叉四枝孢 Tetracladium furcatum,芒四绺孢Tetraploa aristata,水生三胞霉 Tricellula aquatica,弯三胞霉T．Curvatis,异常三枝孢 Tricladium anomalum,毛三枝孢 T. chaetocladium,香桃木多绺孢 Tripospermum myrti,尖火箭孢Triscelophorus acuminatus,大变孢霉Varicosporium giganteum,橙色鸟孢霉 Volucrispora aurantiaca和榛鸟孢霉V．Ornithomorpha等。     

中国弯孢属的分类研究II

报道弯孢属的两个新种,柱弯孢Curvularia cylindrica和拟棒弯孢Curvulariatra chycarpi,前者生于葱Allium fistulosum上,后者生于棕榈Trachycarpus fortunei上。柱弯孢的分生孢子柱状细长,4个隔膜,这是区别于其它种的显著特征。拟棒弯孢的形态与棒弯孢C.clavata B.L.Jain近似,但是其分生孢子明显的大于后者。研究标本保存在山东农业大学植物病理学标本室(HSAUP)。     

中国弯孢属分类研究Ⅰ. ——生于禾本科植物上的一个新种和一个中国新记录种

报道生于禾本科Gramineae植物上的弯孢属真菌一个新种,薏苡生弯孢Curvularia coicicola,和一个中国新记录种,黄茅弯孢 Curvularia heteropogonis Alcorn。新种S形、淡色的分生孢子是区别于其它弯孢种的显著特征。研究标本保藏在山东农业大学植物病理标本室(HSAUP)。     

中国的新月孢属真菌

本文报道了我国新月孢属真菌Harposporium anguillulae,Harcuatum,H crassum,Hlilliptotanum,H. oxyeoracum和一个新种——小旋孢新月孢Harposporium microspirale sp,nov.。新种主要特征为球形瓶梗上着生1～3个小梗,孢子微旋,9．6～13．9×0．6～0．9μm.     

用新月弯孢霉11β-羟基化16a-甲基化合物RS-21醋酸酯

对新月弯孢霉AS3．4381的菌丝体转化16a-甲基Reicbstein's 化合物S21-醋酸酯(I)生成16a-甲基氢化可的松(II)进行了研究。培养24h的菌丝体的11β-羟基化活性最高;乙醇对此羟基化活性的抑制作用明显。当(1)浓度为0.15％,转化72h,产物(II)的重量收率为55.4％。     

新月弯孢霉原生质体制备及再生条件的研究

以从自然界中筛选的新月弯孢霉（Ｃｕｒｖｕｌａｒｉａｌｕｎａｔａ）Ｄ－１为出发菌株,进行原生质体制备及再生条件的研究。将培养至１６ｈ的Ｄ－１菌丝体经ＤＴＴ溶液处理３０ｍｉｎ后,用溶壁酶和纤维素酶的混合酶液于３０℃下酶解４ｈ,原生质体释放量达到６．０×１０^６个／ｍＬ,原生质体再生率为８．３％。     

腔孢纲一新属——珊座孢属

本文报道寄生于云南水稻上半知菌中腔孢纲一新属。 此菌子实体为扁球形的表生子座,子座含外子座和内子座;分生孢子腔生于内子座,珊瑚状,无孔口;分生孢子梗生于腔室内壁上,无色无隔,倒棍棒形,细而长;分生孢子无色,链生,有或无隔,长椭圆形或长卵形。根据上述特征被鉴定为新属、新种,命名为珊座孢新属Corallocytostroma Yu et Zhang gen. Nov. 和稻珊座孢新种 Corallocytostroma oryzae Yu et Zhang sp. Nov. 此菌也是水稻上的一种新病害(穗果病)的病原菌,危害在不断增加,值得注意。     

甾体C11β—羟基生物转化菌株新月弯孢霉的筛选和鉴定

文章对甾体C11β－羟某化生物转化菌株－新月弯孢霉的生长和生物转化特征进行了研究。经过反复筛选,最终选出了一株氧化可的松转化率达30％的最优菌株。文中描述了新月弯孢霉菌体生长过程中,菌体干重与PH的变化情况,并通过正交实验确定了该菌株生长的最适培养基配方。经过研究,对新月弯孢霉菌株的生长和生物转化特性及其进行甾体C11β－羟基化生物转化过程有了初步的了解。     

中国热带地区的半知菌I.云南尾孢菌属及其近似属的种

本文报道云南热带地区尾孢菌属及其近似属真菌45种,其中有一个新种：番木瓜短胖孢(Cercosporidium papayae Y．L Guo,sp．nov．),寄生在番木瓜科(Caricaceae)番木瓜(Carica papaya L)叶上。短胖孢属真菌在番木瓜科植物上是首次报道。文中为新种提供了拉丁文简介、描述并附图。模式标本保藏在中国科学院微生物研究所真菌标本室(HMAS)。寄生在番木瓜(Carica papaya L)上的Cercospora mamaonis Vicgas ＆ Chupp与本种近似,二者都具有子座。分生孢子梗紧密簇生,但前者分生孢子梗(5～25×2～3μm)和分生孢子(10～45×2～3μm)均短而窄。番木瓜尾孢(Cercospora papayae Hansf.)与本种的区别在于无子座,分生孢子梗色泽深(中度褐色),分生孢子梗长(50～200×3.5～6μm),分生孢子无色,针形,窄(20～75×3～5μm)。     

黄孢原毛平革菌基因启动子的分离与鉴定

利用启动子探针型载体pSUPV8直接在大肠杆菌(Escherichia coli)中分离黄孢原毛平革菌(Phanerochaete chrysosporium)基因启动子片段,获得6个潮霉素抗性(Hyg-r)重组子。对重组子CH2、CH6进行序列分析,结果发现它们都存在真核生物基因启动子的保守序列;用原生质体转化法将其转化黄孢原毛平革菌,仅pCH6获得了潮霉素抗性转化子;PCR和斑点杂交分析表明,pCH6已成功导入黄孢原毛平革菌,并启动潮霉素抗性基因的表达。     

Solid state cultivation of Curvularia lunata for transformation of rifamycin B to S

Biotransformation of rifamycin B to rifamycin S using two strains of C. lunata namely NCIM 716 and NMU grown on various solid substrates viz., grass, paper, jowar/wheat straw, bran and bagasse was studied. Almost complete biotransformation efficiency of rifamycin B at 0. 06 mM concentration was observed within 24 hr. Among these two strains, C. lunata NMU showed 90% of biotransformation and higher rate of cellulose utilization on solid substrates vis-à-vis reference strain. Cellulase activity of both strains was also studied for exoglucanase, endoglucanase and beta-glucosidase. Column bioreactor studies with bagasse revealed further improvement in biotransformation efficiency of C. lunata NMU.     

Toxigenicity of fungi from grain sorghum

The mycoflora of nine varieties of grain sorghum was determined by plating serial dilutions of ground samples on rose bengal-streptomycin agar. Seventeen species of fungi representing 10 genera were identified. Curvularia, Penicillium, Mucor, and Aspergillus were dominant genera. Extracts of P. herquei were highly toxic to brine shrimp, while those of C. clavata, C. lunata, and Mucor mucedo showed low to moderate toxicity. Extracts of C. clavata, C. lunata, and M. mucedo were highly toxic to chicken embryos; those of six other species showed low to moderate toxicity. Extracts of C. clavata, C. lunata, M. mucedo, Fusarium moniliforme, Alternaria tenuissima, P. herquei, and P. steckii showed varying degrees of toxicity to day-old cockerels.     

玉米弯孢叶斑病菌的形态学分类与RAPD分析

对16个供试弯孢分离株根据其分生孢子的形态进行分类,其中12个为新月弯孢(Curvularia luna-ta),其余4个是画眉草弯孢(C.eragrostidis)。对这些分离株基因组DNA进行RAPD分析发现,一些分属于两种不同弯孢菌的分离株间比同种弯孢的分离株间具有更近的遗传距离,即具有更近的亲缘关系。因此,根据弯孢菌的形态分类和利用RAPD标记的分类结果存在不一致现象。     

Ultrastructure and genotypic characterization of the filamentous fungus Cochliobolus lunatus in comparison to the anamorphic strain Curvularia lunata

Abstract Although Curvularia lunata is classified as a conidial anamorph of Cochliobolus lunatus , the electron microscopic studies revealed the ultrastructure of both strains to be significantly different. C. lunatus m118 grows in the hyphal form characterized by a thick cell wall and numerous lipid bodies. C. lunata forms thinner hyphae of various sizes and large oval spores. Electrophoretic karyotypes of C. lunatus m118 (this paper) and C. lunata AT46 (Osiewacz, H. and Ridder, R. (1991) Curr. Genet. 20, 151–155) as well as RAPD-PCR analysis with the primer (GTG)₅ indicate close genetic relationship of both microorganisms.     

一株产漆酶真菌新月弯孢霉JQH-100在染料脱色中的应用

从感染叶斑病的玉米叶片中分离、纯化得到一株高产漆酶的新月弯孢霉Curvularia lunata JQH-100菌株。液体培养Curvularia lunata JQH-100可产漆酶且活性较高,产酶高峰出现在第3天;以ABTS为底物粗酶液的最适反应温度是30℃,最适反应pH是2.8;染料脱色的研究表明,共培养体系对茜素红的脱色率达到了92.6%,对中性红和刚果红的脱色率也都在80%以上;Curvularia lunata JQH-100所产漆酶经纯化后对染料茜素红和刚果红有较高的脱色率,分别为82.1%和81.2%。研究结果显示Curvularia lunata JQH-100在染料废水处理中有较大应用潜力。     

Melanin biosynthesis in the fungus Curvularia lunata (teleomorph: Cochliobolus lunatus)

Curvularia lunata (teleomorph: Cochliobolus lunatus) is a known plant and human pathogen. Tricyclazole, a specific inhibitor of pentaketide melanin biosynthesis, blocked the biosynthesis of melanin in Curvularia lunata and caused the accumulation of the melanin metabolites flaviolin and 2-hydroxyjuglone. This showed that melanin in Curvularia lunata is produced by a pentaketide pathway from 1,8-dihydroxynaphthalene. The 1,3,8-trihydroxynaphthalene reductase (3HNR) gene, associated with the melanin pathway of Curvularia lunata, was identified and characterized. An alignment of 3HNR sequences enabled the design of primers covering conserved regions. A PCR-amplified fragment of Curvularia lunata genomic DNA was used for screening the cDNA library. Three independent cDNA clones revealed an 801-bp open reading frame encoding a 267 amino acid protein. The protein was expressed in Escherichia coli and purified to homogeneity. The predicted amino acid sequence of the 28.6-kDa protein demonstrated homology to other fungal 3HNR and other members of the short-chain dehydrogenase super family. Northern analyses revealed that 3HNR from Curvularia lunata is expressed synchronously with melanization after 3 days of Curvularia lunata growth in malt extract medium. No 3HNR reductase gene expression nor melanization was observed when Curvularia lunata was grown in yeast nitrogen base medium.     

Towards the first inhibitors of trihydroxynaphthalene reductase from Curvularia lunata: synthesis of artificial substrate, homology modelling and initial screening

Trihydroxynaphthalene reductase (3HNR) is an essential enzyme in the biosynthesis of fungal melanin and it represents an emerging target for the development of new fungicides and antimicotics. To promote the discovery of new inhibitors, an improved chemical synthesis of the artificial substrate 2,3-dihydro-2,5-dihydroxy-4H-benzopyran-4-one (DDBO) was developed. A series of compounds were screened on 3HNR from Curvularia lunata, a known plant pathogen and an opportunistic human pathogen, and several structurally diverse hits were obtained. Homology modelling of 3HNR from C. lunata can explain their binding modes and will enable further structure-based design of new and improved inhibitors.     

Accumulation of HDMBOA-Glc is induced by biotic stresses prior to the release of MBOA in maize leaves

The effects of biotic stresses on the contents of benzoxazinones (Bxs) were investigated in maize leaves. When the causal agent of southern corn leaf blight, Bipolaris maydis, was inoculated on the third leaf, the amount of 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (HDMBOA-Glc) increased, reaching a maximum level 48 h after inoculation. The inoculation of weakly pathogenic Curvularia lunata and non-pathogenic Alternaria alternata also resulted in accumulation of HDMBOA-Glc, and filtrates of the cultures of B. maydis, C. lunata and A. alternata also showed the accumulation of elicitor-active compounds by the fungi. Furthermore the infection of B. maydis induced formation of dark brown lesions, where most abundant Bx-related compound was 6-methoxy-2-benzoxazolinone (MBOA). The later is formed by degradation of DIMBOA and HDMBOA, whereas HDMBOA-Glc was most abundant in the surrounding green tissues. Among the Bx-related compounds, MBOA exhibited the strongest inhibition of the germination of the conidia and of the growth of germ tubes of B. maydis, C. lunata and A. alternata. In addition to fungal infection, the feeding by rice armyworm larvae resulted in HDMBOA-Glc accumulation. These findings are discussed in relation to the possible ecological relevance of the conversion of DIMBOA-Glc into HDMBOA-Glc.     

Effect of temperature on the infectivity of metacercariae of Zygocotyle lunata (Digenea: Paramphistomidae)

As a test of the energy limitation hypothesis (ELH), we predicted that temperature would have a significant influence on the infectivity of metacercariae of the digenetic trematode Zygocotyle lunata. Snails infected with Z. lunata were collected from ponds near Crawfordsville, Indiana, isolated at room temperature, and examined for the release of cercariae. Newly encysted metacercariae were collected and incubated 1-30 days at 1 of 5 temperatures (0, 3, 25, 31, 37 C). Twenty-five cysts were fed to each of 5 or 10 mice per treatment group (temperature). At 17 days postinfection, mice were killed and worms were recovered; data were collected on levels of infection in each group and the total body area of each worm. No worms were found in mice fed cysts that had been held at 0 C or 37 C (after 30 days). There were no differences in prevalence, infectivity, or mean intensity among the 3, 25, and 31 C treatments. Infectivity of metacercariae incubated at 37 C for 1 day was significantly greater than in all other treatments, while infectivity of metacercariae in the 37 C/15-day treatment was significantly lower than in all others. Mean body area of worms at 37 C/15 days was significantly greater than at other temperatures, suggesting density-dependent increases in growth. These results, particularly those from the 37 C treatments, are consistent with the ELH; infectivity was lower at high temperatures or when incubated for more time at 1 temperature (fewer energy reserves). It is suggested that microhabitat conditions experienced by metacercariae of Z. lunata could contribute to longer larval life, thus influencing this parasite's temporal dispersal.