Hernández Orville, Tamayo Diana, Torres Isaura, McEwen Juan Guillermo, García Ana María
Instituto de Biología, Universidad de Antioquia, Medellín, Colombia.
Biomedica. 2011 Oct-Dec;31(4):570-9. doi: 10.1590/S0120-41572011000400012.
Paracoccidioidomycosis is an endemic systemic mycosis caused by Paracoccidioides brasiliensis, a thermally dimorphic fungus that in tissues and cultures at 37°C grows as a yeast while at lower temperatures (less than 24°C) it becomes a mold; however the genes that rule these processes and their expression are poorly understood.
This research focused on the kinetic expression of certain genes in P. brasiliensis throughout the dimorphic process, one that involves the transition from the mycelium to yeast forms and the germination from the yeast to mycelium form.
A real-time quantitative polymerase chain reaction (RT-qPCR) was optimized to measure the expression of ten genes connected with diverse cellular functions including cell synthesis and wall structure, oxidative stress response, heat shock response, metabolism, proteins' processing, solute transport across the cell membrane and signal transduction pathways at different time points during the mycelia to yeast transition, as well as in the yeast to mycelia germination processes.
Genes involved in cell synthesis and wall structure, metabolism and signal transduction were differentially expressed and highly up-regulated during the yeast to mycelia germination process; on the other hand, genes involved in heat shock response, cell synthesis and wall structure were highly up-regulated during the mycelia to yeast transition process. The remaining genes were differentially regulated during both processes.
In this work the up-regulation of certain genes involved in the morphological changes occurring in P. brasiliensis yeast and mycelia forms were confirmed, indicating that these biological processes play an important role during the host-pathogen interactions, as well as in the fungus adaptation to environmental conditions.
副球孢子菌病是一种由巴西副球孢子菌引起的地方性系统性真菌病，巴西副球孢子菌是一种温度双相真菌，在组织和37℃培养时以酵母形式生长，而在较低温度（低于24℃）下则变成霉菌；然而，调控这些过程及其表达的基因仍知之甚少。
本研究聚焦于巴西副球孢子菌在双相过程中某些基因的动力学表达，该过程涉及从菌丝体到酵母形式的转变以及从酵母到菌丝体形式的萌发。
优化了实时定量聚合酶链反应（RT-qPCR），以测量与多种细胞功能相关的十个基因的表达，这些功能包括细胞合成和细胞壁结构、氧化应激反应、热休克反应、代谢、蛋白质加工、溶质跨细胞膜运输以及信号转导途径，在菌丝体到酵母转变的不同时间点，以及酵母到菌丝体萌发过程中进行测量。
参与细胞合成和细胞壁结构、代谢以及信号转导的基因在酵母到菌丝体萌发过程中差异表达且高度上调；另一方面，参与热休克反应、细胞合成和细胞壁结构的基因在菌丝体到酵母转变过程中高度上调。其余基因在两个过程中均受到差异调控。
在本研究中，证实了参与巴西副球孢子菌酵母和菌丝体形式形态变化的某些基因上调，表明这些生物学过程在宿主-病原体相互作用以及真菌适应环境条件过程中发挥重要作用。
