Influence of light on the morphological changes that take place during the development of the <Emphasis Type="Italic">Flammulina velutipes</Emphasis> fruit body

We show that fruit bodies of Flammulina velutipes can be induced in complete darkness after a sharp temperature reduction (23° to 16°C). However, the fruit bodies that form in complete darkness have a long stipe with an undeveloped pileus on the top (pinhead fruit bodies) and are thinner and whiter than the normal fruit bodies which are formed in the light. This finding suggests that F. velutipes fruit bodies cannot mature in complete darkness. However, when we irradiated the fruit bodies that had formed in complete darkness, a pileus developed immediately, and 4 days later the separation between the stipe and the pileus could be observed. Immediately after light exposure, the stipe also thickened and became increasingly pigmented. The stipe elongation was inhibited until 8 days after light exposure, although stipe elongation progressed very quickly thereafter. Basidospores were also visible in the gills 8 days after light exposure. We consider that the basidiospore development is involved in this rapid stipe elongation, which aids the effective dispersal of basidiospores.     

Basidiomycetous fungus Flammulina velutipes harbors two linear mitochondrial plasmids encoding DNA and RNA polymerases

Basidiomycetous fungus Flammulina velutipes R15 strain had two linear plasmids in its mitochondria designated pFV1 and pFV2. They were double-stranded DNAs, whose sizes were 8.3 and 8.9 kb, respectively. Sequencing analysis of 7364 bases of the pFV1 and 6861 bases of the pFV2 revealed that the both plasmids had one set of two open reading frames (ORFs) each of that encoded putative DNA and RNA polymerases similar to those of mitochondrial plasmids in other filamentous fungi. In phylogenetic analysis of deduced amino acid sequences of the ORFs and counterparts of other filamentous fungi, the pFV2 was expectedly clustered with plasmids of basidiomycetous fungi. whereas the pFV1 with kalilo plasmid of ascomycetous fungus Neurospora intermedia.     

金针菇液态发酵培养基的筛选

研究不同碳源、氮源及无机盐对金针菇菌丝体产量的影响,采用正交设计法进行金针菇液态发酵培养基配方筛选和优化,确定了最佳培养基配方为大米粉3%、酵母粉1%、KH2PO40.1%、MgSO4.7H2O 0.05%。同时利用此配方培养测定了发酵过程pH、还原糖和氨基氮含量的变化,结果表明:发酵过程中pH变化很小,培养末期略有上升;还原糖含量呈先增后降的变化,氨基氮含量呈上升趋势。     

Production of enokipodins A, B, C, and D: a new group of antimicrobial metabolites from mycelial culture of Flammulina velutipes

Antimicrobial compounds enokipodins A, B, C, and D were originally isolated from the culture filtrates of Flammulina velutipes mycelial culture. Analysis of antibacterial activity by the paper disk method and quantification of enokipodins A–D by high performance liquid chromatography (HPLC) showed that F. velutipes mycelia produced enokipodins A–D in their late growing phase. Great genetic variability in production of these compounds was observed among ten strains of F. velutipes in analyses of antimicrobial activity by the hole-plate diffusion method and quantification by HPLC. Enokipodins A–D demonstrated antimicrobial activity mainly against the gram-positive bacteria Bacillus subtilis and Staphylococcus aureus. Evaluation of minimum inhibitory doses (MIDs) showed that MIDs of enokipodins A and C for B. subtilis were as low as that of the penicillin G antibiotic.     

He-Ne激光对金针菇SOD高产株的诱变效应

用He-Ne激光辐照诱金针茹（Flammulina Velutipes）的原生质体、菌丝体片段,分生孢子悬液,并进行初筛、复筛及突变株遗传稳定性研究。结果表明：采用原生质体进行诱变,其正突变率,单株SOD产量提高率,产SOD遗传稳定性均高于菌系体与分生孢子。激光诱变原生质体是获得金针茹SOD高产株的有效途径。     

金针菇淀粉酶家族基因鉴定及其表达特性分析

本研究对金针菇淀粉酶家族基因进行了信息分析,并选用金针菇双核菌株H1123作为实验材料,分析了菌丝生长过程中淀粉酶活性和淀粉酶基因表达特性之间的关系。结果表明,金针菇淀粉酶家族包含6个α淀粉酶和1个γ淀粉酶。7个淀粉酶基因的表达量均在菌丝接种后第10天出现峰值,并与胞外淀粉酶活性呈同步变化,说明基质中淀粉的分解和利用是淀粉酶家族各成员之间相互协调的结果。其中α-Amy-1、α-Amy-4、α-Amy-5的上调幅度最大,为淀粉降解和代谢过程的主效基因。值得注意的是胞内淀粉酶基因α-Amy-1在第10天时达到约90倍的上调表达水平。我们推测：金针菇胞外淀粉酶将淀粉分解为小分子单糖的同时,其胞内淀粉酶也参与了这些糖类的吸收和运输过程。     

高通量测序检测金针菇RNAi转化子插入位点及拷贝数

本研究对金针菇Flammulina velutipes的一个RNAi转化子菌株1382R3进行了高通量测序,以本实验室先前获得的野生型W23基因组数据为参考,分析了该转化子的基因插入位点以及拷贝数。转化子菌株1382R3是通过农杆菌介导将fv-hmg1-RNAi载体转化至金针菇菌株并通过PCR检测筛选标记而得到。通过BLAST将转化子测序的reads对外源载体和基因组定位,找到具有基因组序列（GS）和外源载体序列（ES）两种序列的临界reads,并据此使用PERL语言程序成功在转化子1382R3菌株中找到两个插入位点。对两个插入位置的序列分析表明：在插入位点1,T-DNA片段部分插入;在插入位点2,T-DNA全部插入到基因组。两个插入位点都对基因组内源基因的表达造成了一定的干扰。此方法拓宽了高通量测序技术的应用范围,将其运用到遗传转化插入位置和拷贝数的研究中,有利于食用菌的功能基因组及基因工程研究。     

Some characteristics of three groups in Flammulina velutipes classified by analysis of esterase isozymes

 Analysis of isozymes was carried out against wild and cultivated commercial stocks of Flammulina velutipes to analyze their genetic differences. Esterase isozymes from F. velutipes showed many bands and variations among the different stocks on the gel. The stocks of F. velutipes in Japan were largely classified into three groups (tentatively named groups A, B, and C) according to the cluster analysis of esterase isozymes. Some characteristics of the three groups were examined. Group C was characterized by a larger spore size, slower spawn running, and a paler pileus color than groups A and B. Furthermore, group B showed a smaller spore size, slower spawn running, and paler pileus color than group A. Received: August 27, 2002 / Accepted: October 10, 2002 Correspondence to:K. Nishizawa     

Lignicolous fungi from northern Serbia as natural sources of antioxidants

As a result of an interest in natural derived metabolites, lignicolous fungi have taken on great importance in biochemical investigations. In the present study, antioxidative screening analyses have included in vitro testing of different extracts (aqueous, methanol, chloroform) of four fungal species using three different assays: Fe²⁺/ascorbate-induced lipid peroxidation by TBA assay, the neutralisation of OH· radicals and the radical scavenging capacity with the DPPHk]assay. TLC analysis confirmed the existance of phenolics in the extracts, but also indicates the presence of some other compounds. The obtained results indicate that MeOH extracts manifested a degree of activity higher than that of CHCl₃ extracts. With respect to antioxidative activity, the extracts can be ranged in the following declining order: G. lucidum, G. applanatum, M. giganteus and F. velutipes. These results suggest that analyzed fungi are of potential interest as sources of strong natural antioxidants that could be used in the food industries and nutrition.     

金针菇营养保健作用

本文对金针菇的营养成份进行了综述,对其生理活性物质、富锌菌丝体、富锗菌丝体及其制剂的生理功能进行了总结。