Mello Thaís Pereira de, Aor Ana Carolina, Oliveira Simone Santiago Carvalho de, Branquinha Marta Helena, Santos André Luis Souza Dos
Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Geral, Laboratório de Investigação de Peptidases, Rio de Janeiro, RJ, Brasil.
Mem Inst Oswaldo Cruz. 2016 Jun 27;0(7):0. doi: 10.1590/0074-02760160200.
In the present study, we have investigated some growth conditions capable of inducing the conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans. Germination in Sabouraud medium (pH 7.0, 37ºC, 5% CO2) showed to be a typically time-dependent event, reaching ~75% in S. minutisporum and > 90% in S. apiospermum, S. aurantiacum and L. prolificans after 4 h. Similar germination rate was observed when conidia were incubated under different media and pHs. Contrarily, temperature and CO2 tension modulated the germination. The isotropic conidial growth (swelling) and germ tube-like projection were evidenced by microscopy and cytometry. Morphometric parameters augmented in a time-dependent fashion, evidencing changes in size and granularity of fungal cells compared with dormant 0 h conidia. In parallel, a clear increase in the mitochondrial activity was measured during the transformation of conidia-into-germinated conidia. Susceptibility profiles to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin varied regarding each morphotype and each fungal species. Overall, the minimal inhibitory concentrations for hyphae were higher than conidia and germinated conidia, except for caspofungin. Collectively, our study add new data about the conidia-into-hyphae transformation in Scedosporium and Lomentospora species, which is a relevant biological process of these molds directly connected to their antifungal resistance and pathogenicity mechanisms.
在本研究中，我们调查了一些能够诱导阿氏枝孢霉、橙色枝孢霉、微小枝孢霉和多育镰孢霉分生孢子萌发的生长条件。在沙氏培养基（pH 7.0，37℃，5%二氧化碳）中萌发显示为典型的时间依赖性事件，4小时后微小枝孢霉的萌发率达到约75%，阿氏枝孢霉、橙色枝孢霉和多育镰孢霉的萌发率>90%。当分生孢子在不同培养基和pH值下培养时，观察到相似的萌发率。相反，温度和二氧化碳张力调节萌发。通过显微镜和细胞计数法证实了各向同性的分生孢子生长（肿胀）和芽管样突起。形态计量学参数随时间呈依赖性增加，表明与休眠0小时的分生孢子相比，真菌细胞的大小和颗粒度发生了变化。同时，在分生孢子转变为萌发分生孢子的过程中，线粒体活性明显增加。对伊曲康唑、氟康唑、伏立康唑、两性霉素B和卡泊芬净的敏感性谱因每种形态型和每种真菌种类而异。总体而言，除卡泊芬净外，对菌丝的最低抑菌浓度高于分生孢子和萌发分生孢子。总的来说，我们的研究增加了关于枝孢霉属和镰孢霉属物种中分生孢子向菌丝转变的新数据，这是这些霉菌的一个相关生物学过程，直接与其抗真菌耐药性和致病机制相关。
