INSTABILITIES OF THE PATHOGENIC YEAST CANDIDA ALBICANS

描述（改编自申请人摘要）：谢尔曼博士及其团队 最近证明，念珠菌的标准实验室菌株 白色念珠菌自发地引起不同类型的殖民 形态突变体与单个和多个总 染色体重排。 有些突变体不稳定， 在进一步亚克隆后产生额外的殖民形式。 最近， 他们已经表明，四个独立的染色体组型， 临床分离株彼此之间都不同，一些染色体 表面上的差异类似于发现的变化， 形态突变体 他们认为染色体畸变 从正常菌株中产生的基因提供了一种遗传变异的手段， 无性微生物 这项建议涉及系统的调查 电泳核型和染色体的模式 与形态学突变体相关的重排和 这些突变体与多种临床分离株的关系。 高分辨率 脉冲场电泳程序分离紧密运行的 染色体和检测异常长度的轻微变化将是 采用正交场交替凝胶电泳（OFAGE）进行 和轮廓钳位双向电场凝胶电泳（CHEF）。 染色体重排将通过杂交来表征， 将分离的NotI和SfiI限制性片段连接到相应的探针上， 位点分布于每条染色体的沿着。 rDNA重复序列的数量， 可能是负责的变化，染色体VIII长度观察 在四个临床分离株和许多形态突变体中， 通过用BamHI（或另一种限制性内切酶）消化总DNA来简单地估计 不切割rDNA的核酸内切酶），用 OFAGE或CHEF，并用rDNA探针进行杂交印迹。 的结果 突变株和独立临床分离株的比较可以提供 相信染色体畸变提供了 遗传变异使得C.白念珠菌适应新的条件 他们的主人。 染色体畸变的模式和类型 稳定和不稳定的突变体可以阐明它们 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.