本文選題：白念珠菌　切入點：二態(tài)性　出處：《第三軍醫(yī)大學》2005年博士論文　論文類型：學位論文

【摘要】：近年來念珠菌感染已成為住院患者血行感染中第三或第四位最常見的病原菌,其中白念珠菌最為常見,占念珠菌屬40-70%。白念珠菌屬人體常居真菌,為條件致病真菌,一般以酶母相存在于機體,當機體免疫功能受到抑制或微生態(tài)失衡時,白念珠菌會轉變其生長形態(tài),可由酵母相轉為菌絲相,進而對機體產(chǎn)生危害。體外培養(yǎng)條件下,白念珠菌也可以酶母相形式或菌絲相形式生長,這種酵母與菌絲之間的轉換稱為菌相轉換。正因為白念珠菌在醫(yī)學中的重要地位,因此對其致病的機制進行了廣泛深入的研究。近年來對白念珠菌的毒力因子研究主要集中于三個方面:①粘附;②酶類;③菌相轉換。 菌相轉換,即酵母相生長轉到菌絲相生長的這一變化是白念珠菌感染轉變的過程,菌絲多則感染率高;另一方面,當天然突變或人工中斷某些基因導致不能形成菌絲的白念珠菌突變菌株,則在動物實驗中表現(xiàn)出毒力的降低或喪失,因此白念珠菌菌絲的形成與發(fā)病有一定的關系。已有的研究證實,菌絲的形成改變白念珠菌各種毒力因子的表達,致菌株毒力增加,感染性增強。 為更全面的尋找白念珠菌酵母相和菌絲相致病相關基因及其毒力因子,本研究應用LongSAGE 技術,定性定量檢測白念珠菌酵母相和菌絲相細胞表達基因的改變,構建白念珠菌酵母相和菌絲相細胞表達基因譜,聚類分析表達基因功能,探討酵母相和菌絲相細胞表達基因與菌相轉換、菌株毒力的相關性。 本研究選擇白念珠菌ATCC-90028 作為研究菌株,經(jīng)RPMI1640 體外誘導形成純的酵母相和菌絲相細胞作為研究材料,經(jīng)顯微鏡下計數(shù)其純度,細胞純度超過95%用于提取RNA;提取純化細胞的RNA 經(jīng)RT-PCR 檢測,證實實驗菌株為白念珠菌,且酵母相細胞無菌絲相細胞污染后,使用分離的RNA 進行LongSAGE 標簽庫的構建,這種使用細胞表型分子與特異性表達基因的雙重篩選,確保RNA 來源于均一性細胞,使經(jīng)LongSAGE 標簽庫分析獲得的基因表達譜,能夠代表該細胞的基因表達特征。
[Abstract]:In recent years, Candida albicans infection has become the third or 4th most common pathogen in blood infection of hospitalized patients, among which Candida albicans is the most common, accounting for 40-70th of Candida. When the immune function of the body is inhibited or the microecology is out of balance, Candida albicans will change its growth form, which can be changed from yeast to hyphae, and then harm to the body. Candida albicans can also grow in the form of an enzyme or a hyphae, and this transition between yeast and hyphae is called phase transition, precisely because of the importance of Candida albicans in medicine. In recent years, the virulence factors of Candida albicans were mainly focused on three aspects: 1: 1 adhesion to 2 enzymes and 3 strains. The transformation of mycelia from yeast to hyphae is the process of infection transformation of Candida albicans, and the infection rate of mycelium is high. When a mutant strain of Candida albicans that is unable to form hyphae due to natural mutation or artificial interruption of certain genes, it shows a decrease or loss of virulence in animal experiments. Therefore, the formation of Candida albicans mycelium has a certain relationship with the development of mycelium, which has been confirmed that the formation of mycelium changes the expression of various virulence factors of Candida albicans, resulting in increased virulence and increased infectivity of Candida albicans. In order to search for the pathogenicity genes and virulence factors of Candida albicans yeast and hyphae more comprehensively, the expression genes of yeast and hyphae of Candida albicans were detected qualitatively and quantitatively by LongSAGE technique. The cell expression gene profiles of Candida albicans in yeast and hyphal phase were constructed, and the function of expressed genes was analyzed by cluster analysis. The relationship between the expression of genes in yeast and hyphae cells and the transformation between yeast and mycelium and the virulence of the strain was discussed. In this study, Candida albicans ATCC-90028 was selected as the study strain, and pure yeast and hyphal phase cells were induced by RPMI1640 in vitro, and their purity was counted under microscope. The RNA of purified cells was identified as Candida albicans by RT-PCR detection, and the isolated RNA was used to construct the LongSAGE tagging library after the yeast phase cells were contaminated with hyphae cells. The double screening of cell phenotypic molecules and specific expressed genes ensures that RNA is derived from homogeneous cells, so that the gene expression profiles obtained by LongSAGE tagging library can represent the gene expression characteristics of the cells.
【學位授予單位】：第三軍醫(yī)大學
【學位級別】：博士
【學位授予年份】：2005
【分類號】：R379

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本文編號：1637615