INSTABILITIES OF THE PATHOGENIC YEAST CANDIDA ALBICANS

描述(摘自申请者摘要)：谢尔曼博士和他的团队 最近证明了念珠菌的标准实验室菌株 白念珠菌自发地产生了不同类型的殖民地 与单个和多个毛发相关的形态突变 染色体重排。其中一些突变体不稳定，并给出了 在进一步的亚克隆之后上升到额外的殖民地形式。最近， 他们已经证明了四个独立的个体的电泳核型。 临床分离株彼此不同，一些染色体 表面上看，差异类似于 形态突变体。他们认为，染色体的异常 从正常菌株产生的基因提供了一种在这种情况下的遗传变异 无性微生物。这项建议涉及一项系统的调查。 电泳法的核型和染色体模式 与形态突变相关的重排及其比较 这些突变株对各种临床分离株具有很强的敏感性。高分辨率 脉冲场电泳法分离紧密运转的细菌 并检测到异常长度的细微变化 正交场变色-凝胶电泳法(OFAGE) 等值线钳制的均匀电场凝胶电泳(CHEF)。 染色体重排将以杂交为特征 将NotI和SfiI限制性片段分离到对应于 每条染色体上都有分布的位点。RDNA重复数，即 可能是所观察到的第八号染色体长度变化的原因 在四个临床分离株和许多形态突变株中，将 只需用BamHI(或其他限制)消化总DNA即可估算 不切割rDNA的内切酶)，用 或厨师，以及与rDNA探针杂交的斑点。评选结果 突变株和独立临床分离株的比较可能会提供 相信这样的假设，即染色体异常正在提供 允许白念珠菌适应新的环境的基因变异 他们的主人。人类染色体异常的模式和类型 稳定和不稳定的突变体揭示了它们的机制 站起来。

DESCRIPTION (Adapted from applicant's abstract): Dr. Sherman and his group have recently demonstrated that standard laboratory strains of Candida albicans spontaneously gave rise to different types of colonial morphological mutants that are associated with single and multiple gross chromosomal rearrangements. Some of the mutants were unstable and gave rise to additional colonial forms after further subcloning. More recently, they have shown that the electrophoretic karyotypes of four independent clinical isolates all differed from each other, and some of the chromosomal differences superficially resembled the alterations uncovered in the morphological mutants. They suggest that the chromosomal aberrations arising from normal strains provide a means for genetic variation in this asexual microorganism. This proposal deals with a systematic investigation of the patterns of electrophoretic karyotypes and chromosomal rearrangements associated with morphological mutants and comparisons of these mutants to a variety of clinical isolates. High resolution procedures of pulse field electrophoresis to separate the closely running chromosomes and to detect slight variations of abnormal lengths will be carried out with orthogonal-field alteration-gel electrophoresis (OFAGE) and contour-clamped homogeneous-electric-field gel electrophoresis (CHEF). The chromosomal rearrangements will be characterized by hybridizing separated NotI and SfiI restriction fragments to probes corresponding to sites distributed along each chromosome. The number of rDNA repeats, that could be responsible for the variation of chromosome VIII length observed in the four clinical isolates and in many morphological mutants, will be estimated simply by digesting total DNA with BamHI (or another restriction endonuclease that does not cleave rDNA), separating the fragments with OFAGE or CHEF, and hybridizing blots with a rDNA probe. The results of the comparisons of the mutants and independent clinical isolates may provide credence to the hypothesis that the chromosomal aberrations are providing genetic variation that allows C. albicans to adapt to new conditions of their host. The patterns and types of chromosomal aberrations in the stable and unstable mutants my shed light on mechanisms by which they arise.