Proteomic analysis of organic sulfur compound utilisation in Advenella mimigardefordensis strain DPN7T

Advenella mandrilli sp. nov., a bacterium isolated from the faeces of Mandrillus sphinx

A novel Gram-negative strain WQ 585^T, isolated from the faeces of mandrills (Mandrillus sphinx) collected at Yunnan Wild Animal Park, Yunnan province, China, was subjected to a polyphasic taxonomic study. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate belongs to the genus Advenella, sharing 98.5% and 98.2% sequence similarity with the type strain Advenella alkanexedens LAM0050^T and Advenella faeciporci M-07^T, respectively. The predominant ubiquinone was Q-8. The major cellular fatty acids (> 10%) were C_16:0, C_17:0 cyclo and Summed Feature 2. The G + C content of the genomic DNA of strain WQ 585^T was 49.0%. The whole genome average nucleotide identity (gANI) values of strain WQ 585^T with strain A. alkanexedens LAM0050^T and A. faeciporci M-07^T were 86.7% and 86.7%, and the digital DNA-DNA hybridization values of strain WQ 585^T with strain A. alkanexedens LAM0050^T and A. faeciporci M-07^T were 64.5% and 62.5%, respectively. Growth occurred at 10-45 °C (optimally at 20-30 °C), pH 6.0-9.0 (optimally at pH 7.0), and 0-5% (w/v) NaCl (optimally at 0.5-2.0%). On the basis of the taxonomic evidence, a novel species, Advenella mandrilli sp. nov., is proposed. The type strain is WQ 585^T (= KCTC 82396 ^T = CCTCC AA 2020028 ^T).

The catabolism of 3,3'-thiodipropionic acid in Variovorax paradoxus strain TBEA6: A proteomic analysis

Variovorax paradoxus strain TBEA6 is one of the few organisms known to utilize 3,3'-thiodipropionate (TDP) as the only source of carbon and energy. It cleaves TDP to 3-mercaptopropionate (3MP), which is a direct precursor for polythioester synthesis. To establish this process in V. paradoxus TBEA6, it is crucial to unravel its TDP metabolism. Therefore, a proteomic approach with subsequent deletion of interesting genes in the bacterium was chosen. Cells were cultivated with D-gluconate, TDP or 3-sulfinopropionate as the only carbon sources. Proteins with high abundances in gels of cells cultivated with either of the organic sulfur compounds were analyzed further. Thereby, we did not only confirm parts of the already postulated TDP metabolism, but also eight new protein candidates for TDP degradation were detected. Deletions of the corresponding genes (two enoyl-CoA hydratases (Ech-20 and Ech-30), an FK506-binding protein, a putative acetolactate synthase, a carnitinyl-CoA dehydratase, and a putative crotonase family protein) were obtained. Only the deletions of both Ech-20 and Ech-30 led to a TDP negative phenotype. The deletion mutant of VPARA_05510, which encodes the putative crotonase family protein showed reduced growth with TDP. The three genes are located in one cluster with genes proven to be involved in TDP metabolism. Thermal shift assays showed an increased stability of Ech-20 with TDP-CoA but not with TDP. These results indicate that Ech-20 uses TDP-CoA as a substrate instead of TDP. Hence, we postulate a new putative pathway for TDP metabolism. Ech-30 interacts with neither TDP-CoA nor TDP but might interact with other CoA-activated intermediates of the proposed pathway. Further enzyme characterization is necessary to unravel the complete pathway from TDP to 3MP.