Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China; Institute of Bioresource and Agriculture, Hong Kong Baptist University, Hong Kong Special Administrative Region, China.
Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China; Institute of Bioresource and Agriculture, Hong Kong Baptist University, Hong Kong Special Administrative Region, China.
Chemosphere. 2022 Sep;302:134748. doi: 10.1016/j.chemosphere.2022.134748. Epub 2022 May 3.
Mold contamination is one of the most important causes for indoor air pollution. Previous studies have indicated the feasibility of employing wet-dry cycles, a special water treatment approach in indoor environments, to control indoor mold contamination. However, the underlying mechanisms regulating the responses of indoor molds to changing moisture conditions remains to be elucidated. Here, we studied the mechanisms regulating the responses to wet-dry cycles (termed as moisture dynamics) in Aspergillus penicillioides, Cladosporium cladosporioides, and Aspergillus niger. First, the dormant spores of each mold species were grown to the swollen stage. Next, swollen spores were incubated at different water activity (a) levels (0.4, 0.6 and 0.8 a) for up to 15 days. Afterward, the viability, lipid peroxidation and antioxidant activities (both enzymatic and non-enzymatic) of treated molds were determined. Our results show that the mold species that survived better under moisture dynamics also encountered less oxidative damage and exhibited stronger antioxidant activities. Moreover, lower RH imposed severer oxidative stress to C. cladosporioides and A. niger. Pearson correlation coefficient indicate significant correlations between oxidative stress and a of dry periods, oxidative damage and mold survival, as well as oxidative responses and mold survival. Collectively, these results imply that oxidative stress adaptation regulates the viability of A. penicillioides, C. cladosporioides, and A. niger in response to moisture dynamics. Our findings facilitate the development of novel engineering solutions for indoor air pollution.
霉菌污染是室内空气污染的最重要原因之一。先前的研究表明，采用干湿循环（室内环境中的一种特殊水处理方法）来控制室内霉菌污染是可行的。然而，调节室内霉菌对变化的水分条件的响应的潜在机制仍有待阐明。在这里，我们研究了调节青霉（Aspergillus penicillioides）、枝孢霉（Cladosporium cladosporioides）和黑曲霉（Aspergillus niger）对干湿循环（称为水分动态）响应的机制。首先，将每种霉菌的休眠孢子培养到肿胀阶段。接下来，将肿胀的孢子在不同的水活度（a）水平（0.4、0.6 和 0.8 a）下孵育长达 15 天。然后，测定处理后的霉菌的活力、脂质过氧化和抗氧化活性（酶和非酶）。我们的结果表明，在水分动态下生存能力更好的霉菌物种也遭遇了较少的氧化损伤，并表现出更强的抗氧化活性。此外，较低的 RH 对 C. cladosporioides 和 A. niger 造成更严重的氧化应激。皮尔逊相关系数表明，氧化应激与干燥期的 a、氧化损伤与霉菌存活率以及氧化反应与霉菌存活率之间存在显著相关性。总的来说，这些结果表明，氧化应激适应调节青霉、枝孢霉和黑曲霉在应对水分动态时的活力。我们的发现为室内空气污染的新型工程解决方案的开发提供了便利。
