Cuéllar-Cruz Mayra, López-Romero Everardo, Ruiz-Baca Estela, Zazueta-Sandoval Roberto
Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, C.P. 36050, Guanajuato, Mexico,
Curr Microbiol. 2014 Nov;69(5):733-9. doi: 10.1007/s00284-014-0651-3. Epub 2014 Jul 8.
Invasive candidiasis is associated with high mortality in immunocompromised and hospitalized patients. Candida albicans is the main pathological agent followed by Candida glabrata, Candida krusei, Candida parapsilosis, and Candida tropicalis. These pathogens colonize different host tissues in humans as they are able to neutralize the reactive species generated from nitrogen and oxygen during the respiratory burst. Among the enzymatic mechanisms that Candida species have developed to protect against free radicals are enzymes with antioxidant and immunodominant functions such as flavohemoglobins, catalases, superoxide dismutases, glutathione reductases, thioredoxins, peroxidases, heat-shock proteins, and enolases. These mechanisms are under transcriptional regulation by factors such as Cta4p, Cwt1p, Yap1p, Skn7p, Msn2p, and Msn4p. However, even though it has been proposed that all Candida species have similar enzymatic systems, it has been observed that they respond differentially to various types of stress. These differential responses may explain the colonization of different organs by each species. Here, we review the enzymatic mechanisms developed by C. albicans and C. glabrata species in response to oxidative and nitrosative stresses. Lack of experimental information for other pathogenic species limits a comparative approach among different organisms.
侵袭性念珠菌病在免疫功能低下和住院患者中与高死亡率相关。白色念珠菌是主要的病原体,其次是光滑念珠菌、克柔念珠菌、近平滑念珠菌和热带念珠菌。这些病原体定植于人类的不同宿主组织,因为它们能够中和呼吸爆发过程中由氮和氧产生的活性物质。在念珠菌属为抵御自由基而发展出的酶促机制中,具有抗氧化和免疫主导功能的酶包括黄素血红蛋白、过氧化氢酶、超氧化物歧化酶、谷胱甘肽还原酶、硫氧还蛋白、过氧化物酶、热休克蛋白和烯醇酶。这些机制受Cta4p、Cwt1p、Yap1p、Skn7p、Msn2p和Msn4p等因子的转录调控。然而,尽管有人提出所有念珠菌属都有相似的酶系统,但已观察到它们对各种应激的反应存在差异。这些差异反应可能解释了每个物种对不同器官的定植情况。在这里,我们综述白色念珠菌和光滑念珠菌属针对氧化应激和亚硝化应激所发展出的酶促机制。其他致病物种缺乏实验信息限制了不同生物体之间的比较研究方法。