红色毛癣菌部分表达序列标签的分析

红色毛癣菌是最常见和流行范围最广的一种浅部致病真菌. 在构建红色毛癣菌cDNA文库的基础上, 获得4002条ESTs. 与GenBank数据库中的序列同源性比较表明, 其中30%(1226条)与其他生物已知功能的基因产物具有不同程度的同源性, 24.81%(989条)仅得到简单的功能提示, 45.19%(1787条)与目前已知的任何蛋白质都没有显著同源性, 为全新的未知功能基因. 对一些与红色毛癣菌生长代谢、信号传导、致病和耐药相关的重要功能基因做了初步分析, 阐明了红色毛癣菌的部分重要代谢途径, 为进一步探索其生理过程、致病和耐药机理, 寻找新的药物靶标提供了重要的分子基础和线索.     

红色毛癣菌的研究进展

红色毛癣菌是最常见的也是世界范围内传播是广的一种皮肤癣菌,属毛癣菌属,本文简述了最近几年在该菌的基因鉴定,基因分类,基因结构的分子生物学研究和免疫学研究方面的主要进展,在基因鉴定中发展了红色毛癣菌特异性探针TR20S和毛癣菌属特异性引物TR1、TR2和NS5,NS6;利用测序方法对毛癣菌属进行了重新分类,并且用探针,限制性片段多态性分析等方法对红色毛癣菌进行了种内分型研究。     

红色毛癣菌致儿童脓癣1例

报道儿童脓癣1例。患儿男,5岁,头部左后侧圆形脓肿破溃结痂伴瘙痒疼痛半个月余。取断发及脓液直接镜检及真菌培养均阳性,做小培养确定菌种为红色毛癣菌,经综合治疗后痊愈。     

红色毛癣菌蛋白酶MEP和SUB的表达及临床意义

目的探讨红色毛癣菌蛋白酶MEP和SUB的表达及临床意义。方法抽提红色毛癣菌总RNA,采用半定量RTPCR法检测红色毛癣菌金属蛋白酶(Metalloproteinases,MEP)、枯草菌素蛋白酶(subtilisins,SUB)基因表达量的变化。结果不同病例的红色毛癣菌SUB的表达水平与临床症状的严重程度密切相关,而与患者的年龄、性别、病程等无明显相关性;MEP的表达水平在不同年龄、性别、病程和临床分型等方面存在一定差异,但无显著意义。结论红色毛癣菌致病力的大小可能与SUB的不同表达有关。     

红色毛癣菌菌株的特异性PCR鉴定方法研究

目的建立一种快速的红色毛癣菌分子生物学鉴定方法。方法根据红色毛癣菌保守区域-真菌核糖体DNA（rDNA）的转录间隔区（ITS）设计特异性引物,采用上游：ITS19865＇GAC ACC AAG AAA AAA TTC TCT GAA GA3＇,下游：ITS24415＇GTC CTG AGG GCG CTG AA3＇为引物对45株红色毛癣菌、5株须癣毛癣菌和1株紫色毛癣菌菌株的DNA进行PCR扩增,观察产物电泳带型的差异。结果 45株红色毛癣菌均能扩增出目的片段,5株须癣毛癣菌和1株紫色毛癣菌均无目的片段扩增出。结论红色毛癣菌可用特异引物PCR方法快速鉴定。     

红色毛癣菌的生物学特性研究

目的 观察红色毛癣菌在不同温度、不同培养基上的生长和产孢情况,并对其进行分子生物学鉴定.方法 ①大培养:采用沙堡葡萄糖琼脂(SDA)和马铃薯葡萄糖琼脂(PDA)平皿,27℃、35℃黑暗培养,测量菌落直径,绘成生长曲线.②小培养(钢圈法):采用SDA、PDA、溴甲酚紫乳固体葡萄糖琼脂(BCP-MSG)、乳蜜琼脂(M)和复合维生素B(VitB)培养基,27℃、30℃黑暗培养,观察镜下菌丝生长、孢子产生情况.③进行rDNA 18S和ITS序列测定.结果 在SDA,PDA上,27℃条件下菌落生长速度较35℃快;在5种培养基上,SDA、PDA产孢较快较多,复合维生素B培养基产孢较慢,但产生大分生孢子较多.30℃产孢更丰富.对部分菌株rDNA ITS、18S PCR扩增产物纯化后直接测序,结果在GenBank中比对、分析,相似度为98%～100%,均鉴定为红色毛癣菌.结论 SDA、PDA均为鉴定和分离红色毛癣菌的合适培养基.5种培养基均可用来刺激红色毛癣菌产孢,其中SDA、PDA产孢较早、较丰富.红色毛癣菌rDNA 18S和ITS序列测定是一种快速准确的红色毛癣菌分子生物学鉴定方法.     

家庭内红色毛癣菌病患者间菌株差异性分析

目的用PCR技术比较分离自同一家庭红色毛癣菌病患者的菌株差异性,分析家庭内多发的红色毛癣菌病的致病菌株是家内相互感染,还是家外感染。方法以家庭内多发的皮肤癣菌病患者为研究对象,分离致病菌株并以传统方法鉴定菌种。再分别用随机扩增多态性DNA(RAPD)和巢式PCR特异扩增红色毛癣菌的串联重复亚元件(TRSS:TRS-1/TRS-2)产生的指纹图谱分析种内株间有无差异性。结果纳入实验的16株菌分离自8个家庭,用形态学等方法及种特异引物均鉴定为红色毛癣菌。RAPD显示4个家庭内的菌株间有差异性,TRS-1区PCR指纹图谱显示5个家庭内菌株有株间差异,TRS-2区能鉴定出2个家庭内菌株间有差异。综合各方法共区分出6个家庭内的菌株间有带型差异。结论该研究提示家庭内多发红色毛癣菌病从家外途径感染率高于家内感染。TRS-1区PCR指纹图谱对红色毛癣菌的菌株区分度高于RAPD,更适于红色毛癣菌株间分型。结合多种分子分型方法可最大限度发现不同菌株间的差异。     

红色毛癣菌孢子期与萌芽期基因表达比较分析

红色毛癣菌(Trichophyton rubrum)是最常见和流行范围最广的一种浅部感染真菌, 它的孢子萌发是和致病密切相关且非常重要的发育过程. 为研究出芽时生理、生化以及细胞学方面的改变, 从红色毛癣菌cDNA文库中选取了3364条有明确功能注释的表达序列标签(ESTs)制备了cDNA芯片, 对孢子期及萌芽期进行了基因表达变化的研究. 数据分析表明, 孢子萌发过程中有335个基因表达上调, 主要是翻译、 修饰蛋白及结构蛋白. 细胞壁和细胞膜组分大量合成, 暗示它们是细胞形态发生的基础. 二组分信号转导系统的组成部分表达上调, 推测它可能在红色毛癣菌孢子萌发过程中起着重要作用. 各种代谢途径表达旺盛, 特别是参与糖酵解和氧化磷酸化的基因基本都上调, 说明在氧气和葡萄糖充足的环境下, 孢子主要通过有氧呼吸获得能量. 本研究对了解红色毛癣菌孢子萌发过程中基因表达的变化及其信号转导和代谢特点提供了重要线索, 对其他浅部真菌的研究也具有重要意义.     

106株红色毛癣菌基因分型与药敏分析CSCD

目的探索海南地区的红色毛癣菌基因型与感染部位、药敏的关系。方法基于红色毛癣菌核糖体rDNA非转录区(NTS)的基因分型进行种内分型,依据“CLSI-M38-A2”方案进行药敏实验。结果106株红色毛癣菌TRS-1基因型有5种带型,其中TypeⅠ52株(49.06%),TypeⅡ14株(13.21%),TypeⅢ5株(4.72%),TypeⅣ型3株(2.83%),其他带型32株(30.18%)。TRS-2基因型有3种带型,其中TypeⅠ68株(64.15%),TypeⅡ6株(5.66%),其他带型32株(30.19%)。药敏结果MIC几何均数由低至高分别为特比萘芬(0.0092μg/mL)、伏立康唑(0.0181μg/mL)、伊曲康唑(0.1491μg/mL)、酮康唑(0.1630μg/mL)、氟康唑(2.3164μg/mL)。有42株菌表现出对抗真菌药物不敏感,不敏感菌株TRS-1和TRS-2分型均以TypeⅠ为主。结论海南地区流行的红色毛癣菌TRS-1和TRS-2基因型均以TypeⅠ为主。以对特比萘芬(0.0092μg/mL)、伏立康唑(0.0181μg/mL)MIC几何均数最低。本结果发现本地区的红色毛癣菌不敏感菌株与基因带型关系不大,也与感染部位无关,可能与来源有关。     

改良CLSI M38-A方案应用于红色毛癣菌的研究进展

国内外学者将改良CLSI M38-A方案应用于红色毛癣菌时进行了改进。这些改进包括红色毛癣菌培养基为燕麦培养基、马铃薯葡萄糖琼脂（PDA）、沙堡弱葡萄糖琼脂（SDA）,接种物仅含小分生孢子,培养基为RPMI1640,接种物量为CFU/ml,培养温度为28℃,培养时间为7 d,MICs终点确定标准为MIC-0,质控菌株选择须癣毛癣菌MRL1957和红色毛癣菌MRL666。     

Comparison between gene expression of conidia and germinating phase in Trichophyton rubrum

Trichophyton rubrum is a dominating superficial dermatophyte, whose conidial germination is correlated to pathopoiesis and a highly important developmental process. To investigate the changes of physiology, biochemistry and cytology during the germination, we selected 3364 function identified ESTs from T. rubrum cDNA library to construct cDNA microarrays, and compared the gene expression levels of conidia and germinating phase. Data analysis indicated that 335 genes were up-regulated during the germination, which mainly encoded translated, modified proteins and structural proteins.The constituents of cell wall and cell membrane were synthetized abundantly, suggesting that they are the foundation of cell morphogenesis. The ingredients of the two-component signal transduction system were up-regulated, presuming that they were important for the conidial germination. Genes of various metabolic pathways were expressed prosperously, especially the genes that participated in glycolysis and oxidative phosphorylation were up-regulated on the whole, demonstrating that in the environment with sufficient oxygen and glucose, conidia obtained energy through aerobic respiration.This paper provides important clues which are helpful to understanding the changes in gene expression, signal conduction and metabolism characteristics during T. rubrum conidial germination, and possess significant meaning to the study of other superficial dermatophytes.     

Comparison between gene expression of conidia and germinating phase in Trichophyton rubrum

Trichophyton rubrum is a dominating superficial dermatophyte, whose conidial germination is correlated to pathopoiesis and a highly important developmental process. To investigate the changes of physiology, biochemistry and cytology during the germination, we selected 3364 function identified ESTs from T. rubrum cDNA library to construct cDNA microarrays, and compared the gene expression levels of conidia and germinating phase. Data analysis indicated that 335 genes were up-regulated during the germination, which mainly encoded translated, modified proteins and structural proteins. The constituents of cell wall and cell membrane were synthetized abundantly, suggesting that they are the foundation of cell morphogenesis. The ingredients of the two-component signal transduction system were up-regulated, presuming that they were important for the conidial germination. Genes of various metabolic pathways were expressed prosperously, especially the genes that participated in glycolysis and oxidative phosphorylation were up-regulated on the whole, demonstrating that in the environment with sufficient oxygen and glucose, conidia obtained energy through aerobic respiration. This paper provides important clues which are helpful to understanding the changes in gene expression, signal conduction and metabolism characteristics during T. rubrum conidial germination, and possess significant meaning to the study of other superficial dermatophytes. Supported by the National High Technology Research and Development Program of China (Grant No. 2001AA223021) and National Key Technologies R&D Programme (Grant No. 2002BA711A14)     

In vitro characterization of Trichophyton rubrum and T. mentagrophytes biofilms

Dermatophytes are fungi responsible for a disease known as dermatophytosis. Biofilms are sessile microbial communities surrounded by extracellular polymeric substances (EPS) with increased resistance to antimicrobial agents and host defenses. This paper describes, for the first time, the characteristics of Trichophyton rubrum and T. mentagrophytes biofilms. Biofilm formation was analyzed by light microscopy, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) as well as by staining with crystal violet and safranin. Metabolic activity was determined using the XTT reduction assay. Both species were able to form mature biofilms in 72?h. T. rubrum biofilm produced more biomass and EPS and was denser than T. mentagrophytes biofilm. The SEM results demonstrated a coordinated network of hyphae in all directions, embedded within EPS in some areas. Research and characterization of biofilms formed by dermatophytes may contribute to the search of new drugs for the treatment of these mycoses and might inform future revisions with respect to the dose and duration of treatment of currently available antifungals.     

Identification of novel secreted proteases during extracellular proteolysis by dermatophytes at acidic pH

The dermatophytes are a group of closely related fungi which are responsible for the great majority of superficial mycoses in humans and animals. Among various potential virulence factors, their secreted proteolytic activity attracts a lot of attention. Most dermatophyte-secreted proteases which have so far been isolated in vitro are neutral or alkaline enzymes. However, inspection of the recently decoded dermatophyte genomes revealed many other hypothetical secreted proteases, in particular acidic proteases similar to those characterized in Aspergillus spp. The validation of such genome predictions instigated the present study on two dermatophyte species, Microsporum canis and Arthroderma benhamiae. Both fungi were found to grow well in a protein medium at acidic pH, accompanied by extracellular proteolysis. Shotgun MS analysis of secreted protein revealed fundamentally different protease profiles during fungal growth in acidic versus neutral pH conditions. Most notably, novel dermatophyte-secreted proteases were identified at acidic pH such as pepsins, sedolisins and acidic carboxypeptidases. Therefore, our results not only support genome predictions, but demonstrate for the first time the secretion of acidic proteases by dermatophytes. Our findings also suggest the existence of different pathways of protein degradation into amino acids and short peptides in these highly specialized pathogenic fungi.     

Amino acid- or protein-dependent growth of Trichophyton mentagrophytes and Trichophyton rubrum

Culture conditions were examined for Trichophyton mentagrophytes and Trichophyton rubrum, which are major pathogens involved in dermatophytosis. They grew well in Sabouraud's dextrose broth or RPMI 1640. Growth in phosphate-buffered yeast nitrogen base supplemented with glucose was very slow, although growth improved significantly with the addition of amino acids or proteins to the medium. The fungi could also grow using human nail fragments as the only source of nutrition. Examination of proteases by substrate gel electrophoresis indicated that distinct sets of proteases are secreted from the dermatophytes in two different media, Sabouraud's dextrose broth and nail fragments. A protease inhibitor, phenylmethanesulfonyl fluoride, inhibited the growth of the fungi on nail fragments, but it did not inhibit their growth in Sabouraud's dextrose broth.     

A Study on Stability of Phenotype and Genotype of Trichophyton rubrum

Objective: To explore the stability of phenotype and genotype in Trichophyton rubrum. Methods: All the strains were cultured on Sabouraud’s dextrose agar slopes, and identified to species level. Strains isolated recently were subcultured on Sabouraud agar slopes four times at an interval of 4 weeks. DNA was extracted with CTAB method. A probe consisting of 3′ end of 18S rDNA, adjacent ITS1, 5.8S rDNA and ITS2 regions was amplified from template DNA of the T. rubrum standard strain using fungal universal primers NS5 and ITS4, labelled by P³² and hybridized with EcoR I-digested T. rubrum genomic DNA. Results: (1) Four phenotypes were isolated from 207 T. rubrum strains, with downy type (45.4%) in the first place, and granular type not found. After 1 year of conservation, 54 strains showed morphological variations with the total variation rate of 26.1%. (2) Eleven strains showed variations in colony morphology or pigment upon subculture. (3) AP-PCR analysis of 10 T. rubrum isolates and one T. rubrum standard strain showed similar DNA patterns with main bands at 2.2, 1.7, 1.3, 0.9 and 0.7 kb. No changes in DNA pattern were found upon subculture. (4) Hybridization analysis revealed that all the 11 T. rubrum strains presented three bands and were identified into two types (2.4, 3.9, 5.9 kb and 2.4, 4.4, 6.5 kb). No changes in band pattern were found upon subculture. Conclusions: Phenotype of T. rubrum was instable and the colonial morphology and pigment easily changed during conservation or subculture, while its genotype was relatively stable.