Project description:Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a persistent nitramine explosive with long-lasting properties. Rhodococcus sp. strain DN22 has been discovered as one of the microorganisms capable of RDX degradation. Despite respectable studies on Rhodococcus sp. strain DN22, the proteins participating in RDX degradation (Oxidoreductase and Cytochrome P450) in the strain remain to be fragments. In this study, complete genome of Rhodococcus sp. strain DN22 was sequenced and analyzed, and the entire sequences of the two genes encoding Oxidoreductase and Cytochrome P450 in Rhodococcus sp. strain DN22 were predicted, which were validated through proteomic data. Besides, despite the identification of certain chemical substances as proposed characterized degradation intermediates of RDX, few studies have investigated the physiological changes and metabolic pathways occurring within Rhodococcus sp. cells when treated with RDX, particularly through the use of mass spectrometry-based omics. Hence, proteomics and metabolomics of Rhodococcus sp. strain DN22 were performed and analyzed with the presence or absence of RDX in the medium. A total of 3186 protein groups were identified and quantified between the two groups, with 117 proteins being significantly differentially expressed proteins. A total of 1056 metabolites were identified after merging positive and negative ion modes, among which 131 metabolites were significantly differential. Through the combined analysis of differential proteomics and metabolomics, several KEGG pathways, including two-component system, ABC transporters, alanine, aspartate and glutamate metabolism, arginine biosynthesis, purine metabolism, nitrogen metabolism, and phosphotransferase system (PTS) were found to be significantly enriched. We expect that our investigation will expand the acquaintance of Rhodococcus sp. strain DN22, and the knowledge of microbial degradation.
Project description:Transcriptome studies confirm the nitrogen limited physiological state of both the wild-type and mutant cells. In addition, multiple differentially expressed genes involved in the synthesis and consumption of pools of acetyl-CoA, acetoacetyl-CoA and 3-hydroxybutyryl-CoA, key metabolites for PHA and TAG synthesis, were identified. An enrichment analysis of differentially expressed genes in the nitrogen starved wild-type versus the isogenic RHA1_ro02104 mutant strain identified genes in the mutant involved in fatty acid and lipid as well as genes involved in acyl-CoA hydrolysis and triacylglycerol degradation. An 8 x 15K array study using total RNA recovered from triplicate cultures of Rhodococcus jostii RHA1 under nitrogen rich and nitrogen starved conditions and triplicate cultures of Rhodococcus jostii RHA1 TadA-homolog deletion mutants (2104) under nitrogen rich and nitrogen starved conditions.
