College of Life and Environmental Science, Wenzhou University, Wenzhou, People's Republic of China.
National and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou University, Wenzhou, People's Republic of China.
PLoS One. 2022 Dec 2;17(12):e0278503. doi: 10.1371/journal.pone.0278503. eCollection 2022.
P-nitrophenol (PNP) is a carcinogenic, teratogenic, and mutagenic compound that can cause serious harm to the environment. A strain of Pseudomonas putida DLL-E4, can efficiently degrade PNP in a complex process that is influenced by many factors. Previous studies showed that the expression level of pnpA, a key gene involved in PNP degradation, was upregulated significantly and the degradation of PNP was obviously accelerated in the presence of glucose. In addition, the expression of crc, crcY, and crcZ, key genes involved in catabolite repression, was downregulated, upregulated, and upregulated, respectively. To investigate the effect of the carbon catabolite repression (CCR) system on PNP degradation, the crc, crcY, and crcZ genes were successfully knocked out by conjugation experiments. Our results showed that the knockout of crc accelerated PNP degradation but slowed down the cell growth. However, the knockout of crcY or crcZ alone accelerated PNP degradation when PNP as the sole carbon source, but that knockout slowed down PNP degradation when glucose was added. The results indicate that the CCR system is involved in the regulation of PNP degradation, and further work is required to determine the details of the specific regulatory mechanism.
对硝基苯酚（PNP）是一种致癌、致畸和致突变的化合物，会对环境造成严重危害。恶臭假单胞菌 DLL-E4 菌株可以通过一个复杂的过程高效降解 PNP，这个过程受许多因素影响。先前的研究表明，参与 PNP 降解的关键基因 pnpA 的表达水平显著上调，并且在葡萄糖存在的情况下，PNP 的降解明显加快。此外，参与分解代谢物阻遏的关键基因 crc、crcY 和 crcZ 的表达分别下调、上调和上调。为了研究碳分解代谢物阻遏（CCR）系统对 PNP 降解的影响，通过接合实验成功敲除了 crc、crcY 和 crcZ 基因。结果表明，crc 的敲除加速了 PNP 的降解，但减缓了细胞的生长。然而，当 PNP 作为唯一的碳源时，crcY 或 crcZ 的单独敲除会加速 PNP 的降解，但当添加葡萄糖时，PNP 的降解会减缓。结果表明，CCR 系统参与了 PNP 降解的调控，需要进一步的工作来确定具体调控机制的细节。
