Hasim Sahar, Vaughn Elyse N, Donohoe Dallas, Gordon Donna M, Pfiffner Susan, Reynolds Todd B
Department of Microbiology, University of Tennessee, Knoxville, TN, 37996, USA.
Department of Nutrition, University of Tennessee, Knoxville, TN, 37996, USA.
Yeast. 2018 Apr;35(4):343-351. doi: 10.1002/yea.3297. Epub 2018 Feb 8.
Candida albicans is among the most common human fungal pathogens. The ability to undergo the morphological transition from yeast to hyphal growth is critical for its pathogenesis. Farnesol, a precursor in the isoprenoid/sterol pathway, is a quorum-sensing molecule produced by C. albicans that inhibits hyphal growth in this polymorphic fungus. Interestingly, C. albicans can tolerate farnesol concentrations that are toxic to other fungi. We hypothesized that changes in phospholipid composition are one of the factors contributing to farnesol tolerance in C. albicans. In this study, we found that loss of enzymes that synthesize the phospholipids phosphatidylserine (PS) and/or phosphatidylethanolamine (PE) compromise the tolerance of C. albicans to farnesol. Compared with wild type, the phospholipid mutant cho1∆/∆ (loss of PS and decreased PE synthesis) shows greater inhibition of growth, loss of ATP production, increased consumption of oxygen, and increased formation of reactive oxygen species in the presence of farnesol. The cho1∆/∆ mutant also exhibits decreased sensitivity to mitochondrial ATPase inhibition, suggesting that cells lacking PS and/or downstream PE rely less on mitochondrial function for ATP synthesis. These data reveal that PS and PE play roles in farnesol tolerance and maintaining mitochondrial respiratory function.
白色念珠菌是最常见的人类真菌病原体之一。从酵母形态转变为菌丝生长的能力对其致病性至关重要。法尼醇是类异戊二烯/甾醇途径中的一种前体,是白色念珠菌产生的一种群体感应分子,可抑制这种多态性真菌的菌丝生长。有趣的是,白色念珠菌能够耐受对其他真菌有毒的法尼醇浓度。我们推测磷脂组成的变化是白色念珠菌对法尼醇耐受性的影响因素之一。在本研究中,我们发现合成磷脂磷脂酰丝氨酸(PS)和/或磷脂酰乙醇胺(PE)的酶的缺失会损害白色念珠菌对法尼醇的耐受性。与野生型相比,磷脂突变体cho1∆/∆(PS缺失且PE合成减少)在法尼醇存在的情况下表现出更大的生长抑制、ATP产生减少、氧气消耗增加和活性氧形成增加。cho1∆/∆突变体对线粒体ATP酶抑制的敏感性也降低,这表明缺乏PS和/或下游PE的细胞在ATP合成中对线粒体功能的依赖较少。这些数据表明PS和PE在法尼醇耐受性和维持线粒体呼吸功能中发挥作用。