产小檗碱诱变菌株培养条件的优化

S-NU-3-2菌株是对源自药用植物黄檗的内生真菌S6进行诱变获得的小檗碱产量比出发菌株有明显提高的突变株,本研究对其培养条件进行了优化,以期进一步提高其产量,为开发利用真菌发酵生产植物活性成分的新途径奠定基础。以菌丝生长和小檗碱产量为指标,筛选出了适宜该菌株发酵的基本培养基、碳源、氮源、光照和培养温度,并经进一步的正交试验优化,得出该高产菌株的最佳培养条件为豆芽汁基本培养基含蔗糖3%,酵母膏0.2%,pH7.0,温度26℃,全光照培养。与初始培养条件相比,在优化后的条件下,该菌株的小檗碱得率提高了47.2%,菌体生物量提高了24%。     

Laccase production and simultaneous decolorization of synthetic dyes in unique inexpensive medium by new isolates of white rot fungus

Morphological and biochemical analysis of the newly isolated white rot fungal (WRF-1) strain has ability to secrete laccase in the economical medium consisted of synthetic dyes, groundnut shell (GNS) and cyanobacterial biomass (algal bloom) under submerged shaking condition at pH 5.0 and 30 °C ± 2 °C temperature. WRF-1 strain was found to decolorize synthetic dyes efficiently at pH 5.0 and 30 °C ± 2 °C temperature. The laccase activity of strain was purified to homogeneity by chromatography with yield up to 70%. The molecular mass of laccase was found to be 70 kDa by SDS-PAGE and isoelectric point was 4.8. Biotransformation of the dyes was followed spectrophotometrically and dyes were found to decolorize completely after 6 days of fermentation. LC-MS studies were used to decipher the degradation profile of synthetic dyes by WRF-1. Indigo carmine gets degraded to isatin sulfonic acid and 4-amino-3-methylbenzenesulphonic acid whereas methyl orange degraded metabolites were identified as p-N,N′-dimethylamine phenyldiazine and p-hydroxybenzene sulfonic acid. Thus the study would give a road map for the production and application of laccase enzyme on a larger scale using low cost substrate.     

蝉拟青霉孢子粉对小菜蛾的致病性试验

试验采用蝉拟青霉(Paecilomyces cicadae)孢子粉处理小菜蛾Plutella xylostella L.幼虫,结果表明,蝉拟青霉可以在小菜蛾幼虫和蛹上寄生,并导致小菜蛾死亡。室内试验,蝉拟青霉对小菜蛾的致死率高达96.55%;田间试验,1.6×107个/mL浓度的022017#蝉拟青霉防治小菜蛾的校正死亡率可达75.86%。该结果可用于蝉拟青霉新型真菌杀虫剂的研制。     

云南美登木内生真菌Beauveria sp.Lr89中的两个环肽

从云南美登木(Maytenus hookeri Loes.)的根部分离到内生真菌Lr89,根据ITS序列分析,鉴定为白僵菌属(Beauveria)真菌。在PDA琼脂平板发酵物中分离得到2个环肽类化合物,经波波谱鉴定为isaridin A(1)和isariin B(2),本文首次报道了这两个化合物的13C NMR数据。     

Aluminium polyphosphate complexes in the mycorrhizal basidiomyceteLaccaria bicolor: A27Al-nuclear magnetic resonance study

The techniques of ²⁷Al- and ³¹P-nuclear magnetic resonance (NMR) spectroscopy were used to investigate the interactions of aluminium with intracellular ligands within the mycelium of the ectomycorrhizal basidiomycete Laccaria bicolor (Maire) Orton (S238). The vegetative mycelium was grown on medium containing 0.5 mM AlCl₃ for 0.5 to 3 d. The ²⁷Al-NMR spectra showed that aluminium was rapidly taken up and accumulated into polyphosphate complexes in the vacuole. Comparison with Al-polyphosphate complexes obtained in vitro on model systems indicated that Al forms at least three mixed-solvation complexes with Pi and polyphosphates, that there is more than one complex present under any set of conditions, and that the equilibrium between these complexes shifts dramatically with Al concentration in the medium. The high phosphate concentrations in the growth medium favoured the accumulation of the Al-polyphosphate complexes. When mycelium containing Al-polyphosphate complexes was transferred to Al-free nutrient solution for 9 d, the Alpolyphosphate complexes were not remobilized. The sequestration of Al in the polyphosphate complexes could therefore make a significant contribution to the protection of mycorrhizal plants against aluminium toxicity.Abbreviations NMR nuclear magnetic resonance - PolyP polyphosphate(s) - PP₁ terminal phosphate of PolyP - PP₃ middle phosphate of PolyP We thank Prof. Daniel Canet (Laboratoire de Méthodologie RMN, University of Nancy I, Vandceuvre-lès-Nancy, France) for his constant encouragement and Christine Delaruelle for skilled technical assistance in growing the fungal cultures. This work was supported by a research grant from the Commission of the European Communities (STEP-CT90-0059, Role of Ectomycorrhiza in Stress Tolerance of Forest Trees) to F.M. and a travel grant from the Institut National de la Recherche Agronomique to I.K.; R.C. is a recipient of a Postdoctoral Fellowship from the Natural Sciences and Engineering Research Council of Canada.     

Purification and characterization of a dextranase from Sporothrix schenckii

A dextranase (EC 3.2.1.11) was purified and characterized from the IP-29 strain of Sporothrix schenckii, a dimorphic pathogenic fungus. Growing cells secreted the enzyme into a standard culture medium (20 °C) that supports the mycelial phase. Soluble bacterial dextrans substituted for glucose as substrate with a small decrease in cellular yield but a tenfold increase in the production of dextranase. This enzyme is a monomeric protein with a molecular mass of 79 kDa, a pH optimum of 5.0, and an action pattern against a soluble 170-kDa bacterial dextran that leads to a final mixture of glucose (38%), isomaltose (38%), and branched oligosaccharides (24%). In the presence of 200 mM sodium acetate buffer (pH 5.0), the K _m for soluble dextran was 0.067 ± 0.003% (w/v). Salts of Hg²⁺, (UO₂)²⁺, Pb²⁺, Cu²⁺, and Zn²⁺ inhibited by affecting both V _max and K _m. The enzyme was most stable between pH values of 4.50 and 4.75, where the half-life at 55 °C was 18 min and the energy of activation for heat denaturation was 99 kcal/mol. S. schenckii dextranase catalyzed the degradation of cross-linked dextran chains in Sephadex G-50 to G-200, and the latter was a good substrate for cell growth at 20 °C. Highly cross-linked grades (i.e., G-10 and G-25) were refractory to hydrolysis. Most strains of S. schenckii from Europe and North America tested positive for dextranase when grown at 20 °C. All of these isolates grew on glucose at 35 °C, a condition that is typically associated with the yeast phase, but they did not express dextranase and were incapable of using dextran as a carbon source at the higher temperature. Received: 29 December 1997 / Accepted: 4 March 1998     

采自武夷山高温木质素降解菌优良菌株筛选及其木质素降解效果测定

本文旨在筛选能够高效降解秸秆木质素的高温真菌。对来自福建武夷山的农田土壤进行富集,采用苯胺蓝、愈创木酚和α-萘酚3种筛选平板结合木质素磺酸钙降解试验筛选木质素高温降解菌,采用范氏洗涤剂法测定一株高效降解菌对秸秆木质素的降解效果;最后以经典形态学和多基因分子系统学相结合的方法对该菌株进行鉴定。结果表明：经钓饵法,分离获得8株高温菌;通过初筛和复筛,获得了1株较好的木质素高温降解菌A12638H;将其用于降解水稻秸秆和玉米秸秆,发现木质素降解率分别达到41.7%和48.3%;该菌株经鉴定为大孢戴氏霉Taifanglania major。菌株A12638H具有很好的应用价值,值得在秸秆资源的开发利用中开展更深入的研究。     

Aspergillus taichungensis,a new species from Taiwan

Aspergillus taichungensis isolated from a soil sample collected in Taiwan is described as a new species. The new species is characterized by its restricted growth on Czapek's and malt extract agars and its white to light yellow colonies, radiate conidial heads, smooth and often diminutive conidiophores, hemispherical to elongate vesicles with biseriate aspergilla (conidiogenous cells), globose, micro-verrucose conidia and dark brown sclerotia. The species somewhat resemblesA. versicolor, A. terreus andA. flavipes, but differs in cultural and morphological details, and is considered to represent an interface species in the subgenusNidulantes.     

Taxonomy of someDiploschistes spp. (lichenized ascomycetes,Thelotremataceae) containing gyrophoric acid

Three species which contain both gyrophoric and lecanoric acids and possess perithecioid ascomata are recognized in the genusDiploschistes. D. badius andD. gyrophoricus are described as new, whileD. subcupreus is reduced to synonymy withD. sticticus. Two species occur in the southern hemisphere, whileD. badius is found in N. America.