The dimorphic yeast Candida albicans is the most common pathogenic fungus found in humans. While this species is normally commensal, a morphological switch from budding yeast to filamentous hyphae allows the fungi to invade epithelial cells and cause infections. The phenotypic change is controlled by the adenylyl cyclase, Cyr1. Interestingly, this protein contains a leucine-rich repeat (LRR) domain, which is commonly found in innate immune receptors from plants and animals. A functional and pure LRR domain was obtained in high yields from E. coli expression. Utilizing a surface plasmon resonance assay, the LRR was found to bind diverse bacterial derived carbohydrates with high affinity. This domain is capable of binding fragments of peptidoglycan, a carbohydrate polymer component of the bacterial cell wall, as well as anthracyclines produced by Streptomyces, leading to hyphae formation. These findings add another dimension to the human microbiome, taking into account yeast-bacteria interactions that occur in the host.

中文翻译：

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细菌衍生的碳水化合物与Cyr1结合并触发白色念珠菌的菌丝生长。

双态酵母白色念珠菌是人类中最常见的致病真菌。虽然该物种通常是共生的，但从发芽的酵母到丝状菌丝的形态转换允许真菌侵入上皮细胞并引起感染。表型变化是由腺苷酸环化酶Cyr1控制的。有趣的是，这种蛋白质包含一个富含亮氨酸的重复（LRR）域，该域通常存在于动植物的先天免疫受体中。从大肠杆菌表达中以高产率获得了功能性和纯净的LRR结构域。利用表面等离振子共振测定法，发现LRR以高亲和力结合各种细菌衍生的碳水化合物。该结构域能够结合肽聚糖的片段，肽聚糖是细菌细胞壁的一种碳水化合物聚合物成分，以及链霉菌产生的蒽环类抗生素，导致形成菌丝。考虑到宿主中发生的酵母菌与细菌的相互作用，这些发现为人类微生物组增加了新的维度。