三颗针对白假丝酵母的抑制作用

目的 研究三颗针对白假丝酵母的抑制作用。方法 采用溴化噻唑蓝四唑法（MTT）和琼脂平板法测定三颗针对白假丝酵母的最低抑菌浓度（MIC）和最低杀菌浓度（MFC）;利用倒置荧光显微镜观察三颗针对白假丝酵母菌丝形成的影响;采用MTT法测定三颗针对白假丝酵母菌丝萌发不同时期的抑制率。结果 三颗针对白假丝酵母具有较强的抑制作用。其中,采用琼脂平板法测得三颗针抑制该菌的MIC为2 mg/mL,MFC为4 mg/mL。三颗针能减缓该菌的生长速度或使其停止生长,且浓度越高作用效果越明显。其中4 mg/mL的三颗针作用白假丝酵母6 h后,能够完全抑制菌丝形成。对于24 h后已经萌发为菌丝态的白假丝酵母,三颗针可抑制菌丝的继续生长,与对照组相比,4 mg/mL的三颗针对于萌发2 h后的白假丝酵母的菌丝抑制率为76.7%（P<0.01）。结论 三颗针能抑制白假丝酵母菌丝的生长和萌发。     

假丝酵母属的聚类分析和代谢活性的研究

本文对35株假丝酵母测定了84项性状,用不同的聚类方法进行了聚类,结果以Ssm系数的UPGMA方式处理较合适。根据UPGMA聚类结果,这些菌株主要分成两大类群。对代谢活性(生理生化性状的阳性百分率,MA%)分析的结果发现,第一类群的代谢活性在40%至73%之间,而第二类群在9%至33%之间,类群间代谢活性有明显差异。实验结果还表明,某些传统鉴定方法中的鉴定指标(如硝酸盐同化等)不能代表类群的特征,而另外一些指标(如MA%,海藻糖、松三糖和麦芽糖的同化等)具有类群的特征性。虫生假丝酵母(C.insectorum)和穿凿假丝酵母(C.terebra)的相似性系数高达90%,这两个种应该合并为一种。     

BDSF对白假丝酵母体外作用的研究

白假丝酵母(又称白念珠菌)是人体重要的条件致病真菌.在正常人体中,白假丝酵母是一种无害共生真菌;在免疫力低下人群中,白假丝酵母可引起假丝酵母病,轻者可导致黏膜感染,重者可发展为系统性疾病,甚至危及生命.白假丝酵母从酵母相至菌丝相的形态转变是极其重要的致病因素之一.BDSF是小分子短链脂肪酸,由Burkholderia cenocepacia分泌产生.对酵母相白假丝酵母,在BDSF≥30 μmol/L时因菌丝生长受强烈抑制,无法从酵母相向菌丝相转变.而对菌丝相白假丝酵母,当BDSF在30 μmol/L和60 μmol/L时,菌丝进一步生长并产生分支,但随菌丝分支生长,新生的分支菌丝不断转变为酵母相;当BDSF增加至120 μmol/L时,菌丝生长和分支状况几乎完全受抑制.由此可见,BDSF不仅强烈抑制菌丝生长,还可促使新生的菌丝相向酵母相转化.     

白假丝酵母检测的研究进展

白念菌病已成为艾滋病等免疫功能低下患者的严重并发症和直接致死原因,是医源性感染的常见病之一,其早期诊断与防治是目前重要的研究课题。本文综述了近年来该菌免疫学及分子生物学检测技术试验与应用的研究进展。     

白假丝酵母活性代谢物种类及分离技术的研究进展

白假丝酵母是常见的条件致病菌,研究其生物机制有重要意义.代谢物作为生物体基因表达的终产物,对其种类和含量的研究可作为基因组学和蛋白质组学的重要补充.本文综述了目前研究中所发现的与白假丝酵母形态学和应激相关的代谢物种类和作用以及其分离和分析方法,为进一步研究其致病机制和耐药性提供参考.     

白假丝酵母形态转换相关基因及其调控途径的研究进展

白假丝酵母可在酵母相和菌丝相之间进行转换,这种形态转换对白假丝酵母的黏附、侵入和逃逸宿主免疫系统攻击的能力等都具有很大的影响。近年来,运用分子生物学方法克隆出了一系列与白假丝酵母形态转换相关的基因,并发现了两条调控其形态转换的信号传导途径。     

热带假丝酵母代谢烷烃过程中的β-氧化和代谢调控

热带假丝酵母 (Ｃａｎｄｉｄａｔｒｏｐｉｃａｌｉｓ)能利用烷烃作唯一碳源和能源。当以烷烃或脂肪酸为碳源时 ,在细胞内可形成大量的过氧化物酶体 (ｐｅｒｏｘｉｓｏｍｅ) ,同时诱导生成脂肪酸 β 氧化酶系 ,当以葡萄糖为碳源时 ,则极少有过氧化物酶体形成[1] ,一些Ｃ .ｔｒｏｐｉｃａｌｉｓ能氧化烷烃生成长链二元酸 (ｌｏｎｇｃｈａｉｎｄｉｃａｒｂｏｘｙｌｉｃａｃｉｄ ,ＤＣＡ)。由于这些特征 ,人们从酶学、分子生物学和实际应用等方面对这种酵母进行了深入研究 ,并阐述了Ｃ .ｔｒｏｐｉｃａｌｉｓ代谢烷烃的途径、脂肪酸β 氧化酶系…     

白假丝酵母二相性及其与致病性关系的研究进展

白假丝酵母是二相性真菌,本文主要综述了近年来有关该茵的形态发育、二相性转移的外界条件、二相性发生的分子生物学基础及二相性与致病性之间关系方面的研究进展。     

白假丝酵母天冬氨酸蛋白酶研究进展

白假丝酵母是免疫功能低下宿主条件致病感染中最常见的病原真菌之一,目前基本已肯定分泌型天冬氨酸蛋白酶(s印)在其致病过程中具有重要作用。现将近年来有关白假丝酵母Sap的研究从其编码基因、分子特性和表达以及在白假丝酵母致病中的作用等作一综述。     

抗系统性白念珠菌感染的先天性免疫

白念珠菌是引起浅部、深部真菌感染常见的病原菌.先天免疫反应在宿主抗系统性白念珠菌感染中起主导作用.介导宿主抗念珠菌感染的先天性免疫包括一系列真菌识别受体及免疫效应细胞.宿主对系统性白念珠菌感染的免疫反应是决定患者预后的关键.本文就宿主抗系统性白念珠菌感染的先天性免疫机制进行综述.     

大鼠白念珠菌支气管肺感染时肺组织Toll样受体2的表达及意义

目的 探讨Toll样受体2(TLR2)在白念珠菌支气管肺感染大鼠肺组织模型中的表达及意义.方法 建立白念珠菌支气管肺感染大鼠模型,观察感染后肺组织病理形态学改变,采用免疫组织化学法观察感染后不同时间(第3天、第7天)白念珠菌支气管肺感染大鼠肺组织TLR2的表达,并与未感染组进行比较.结果 大鼠白念珠菌支气管肺感染后肺组织TLR2表达水平明显升高.结论 白念珠菌支气管肺感染肺组织TLR2表达增高可能参与感染的炎症反应.     

大鼠支气管肺白念珠菌感染后血清IL-17水平及意义

目的探讨大鼠支气管肺白念珠菌感染后血清白细胞介素17(IL-17)的变化及意义。方法将24只Sprague Dawley(以下简称SD)健康雄性鼠随机分为3组,每组8只,免疫低下+白念珠菌感染组(阳性对照组);免疫低下+生理盐水组(阴性对照组);免疫正常+白念珠菌感染组(实验组)。因为实验过程中存在大鼠死亡,最终每组各有6只大鼠完成实验。系统应用糖皮质激素建立免疫低下的大鼠模型;实验组及阳性对照组使用标准白念珠菌菌株混悬液经气管插管注入而建立感染模型;阴性对照组使用生理盐水作对照。感染后第1、3、5、7天使用尾静脉取血分离血清;酶联免疫吸附法(ELISA)检测血清IL-17水平;第7天取血后处死大鼠,取右肺下叶组织进行HE染色观察。结果第3、5天实验组血清IL-17水平高于对照组,而第1、7天3组间无差异;两对照组IL-17水平无差异。肺组织病理:实验组呈明显炎症反应;阳性对照组呈轻微炎症反应;阴性对照组未见明显炎性细胞浸润。结论大鼠白念珠菌支气管肺感染后,免疫正常的大鼠在感染中期血清IL-17水平升高,IL-17可能通过促进中性粒细胞在气道的聚集而参与炎症反应;IL-17的水平与机体炎症反应呈正相关;IL-17在气道白念珠菌感染后炎症介导及机体防御机制的调动中起一定作用。     

念珠菌性阴道炎小鼠模型的建立

目的建立念珠菌定植的阴道感染小鼠模型。方法先用林可霉素溶液(浓度为100mg/ml)冲洗小鼠阴道,再将念珠菌接种到小鼠阴道内。结果模型组小鼠阴道内主要细菌数量乳杆菌显著下降(P<0.01),出现阴道红肿、分泌物多呈块状和阴道黏膜充血等念珠菌阴道炎的典型症状。结论通过抗生素处理后,再在小鼠阴道内接种念珠菌,念珠菌能在小鼠阴道内定植,即建立了念珠菌性阴道炎的小鼠模型。     

Immunomodulatory and protective effect of probiotic Lactobacillus casei against Candida albicans infection in malnourished mice

The effect of Lactobacillus casei CRL 431 (Lc), when administered as a supplement to a repletion diet, on the resistance of malnourished mice to Candida albicans infection was studied. Weaned mice were malnourished by being given a protein-free diet (PFD) for 21 days. The malnourished mice were then fed a balanced conventional diet (BCD) for 7 days or BCD for 7 days with supplemental Lc on days 6 and 7 (BCD+Lc). Malnourished (MNC) and well-nourished (WNC) mice were used as controls. At the end of the treatments the mice were infected intraperitoneally with C. albicans. Animals that had received probiotics had improved survival and resistance against this infection compared to those in the BCD and MNC groups. The number and fungicidal activity of phagocytes, and the concentrations of tumor necrosis factor-α, interferon-γ and interleukin-6 (IL-6), increased in blood and infected tissues in all experimental groups, but MNC mice showed lower concentrations than those in the WNC group. BCD and BCD+Lc mice showed higher concentrations of these variables than those in the MNC group, but only the BCD+Lc group presented values similar to the WNC mice. Malnutrition also impaired the production of IL-17 and IL-10 in response to infection. Both repletion treatments normalized IL-17 concentrations, but IL-10 in the BCD+Lc group was significantly higher than in WNC mice. The addition of L. casei to the repletion diet normalized the immune response against C. albicans, allowing efficient recruitment and activation of phagocytes, as well as effective release of pro-inflammatory cytokines. In addition, probiotic treatment induced an increase in IL-10 concentrations, which would have helped to prevent damage caused by the inflammatory response.     

Candida glabrata and Candida albicans; dissimilar tissue tropism and infectivity in a gnotobiotic model of mucosal candidiasis

Germ-free transgenic epsilon 26 (Tgepsilon26) mice, deficient in both natural killer (NK)- and T-cells, were inoculated (orally) with each of two Candida glabrata (BG2 or BG1003) or Candida albicans (CAF2-1 or SC5314) strains. Candida glabrata- or C. albicans-colonized mice exhibited similar numbers of viable Candida in the alimentary tract. Neither C. glabrata nor C. albicans caused systemic candidiasis of endogenous (alimentary tract) origin. Candida albicans invaded oroesophageal (tongue, palate, esophagus) and keratinized gastric tissues, evoked hyperkeratosis and a prominent, chronic, granulocyte-dominated, inflammatory response in all infected tissues, stimulated the production of splenic granulocytes and was lethal for the mice within 3-5 weeks after oral colonization. The two C. glabrata strains colonized the alimentary tract and penetrated into the keratinized (cardia-antrum) gastric tissues, but in contrast to C. albicans, were unable to infect oroesophageal tissues. Furthermore, C. glabrata strains were not lethal for the Tgepsilon26 mice, and did not evoke an inflammatory response in colonized gastric tissues or stimulate the production of splenic granulocytes. This 'stealth-like' behavior could explain the ability of C. glabrata to persist in infected tissues and survive as a commensal in the alimentary tract.     

Avirulence of Candida albicans auxotrophic mutants in a rat model of oropharyngeal candidiasis

Abstract The virulence of Candida albicans strain SC5413 and two isogenic derivatives have been investigated in a rat model of oropharyngeal candidiasis. The results demonstrate that both mutant strains are avirulent in this animal model while the parental strain readily initiates infection. Avirulence is not related to altered growth characteristics or the inability of the strains to undergo yeast-to-hyphal morphogenesis. The potential importance of nutritional sufficiency as a virulence factor as well as the possibility of utilizing such strains in the development of an in vitro expression technology system for Candida albicans is discussed.     

Azole sensitivity in Candida albicans

Abstract In the present study, we assessed the influence of three culture media on the susceptibility 'in vitro' of twenty four clinical strains belonging to Candida albicans against three imidazole-derivatives and also, we investigated the situation of azole sensitivity in three of these strains.