Substrate-dependent transcriptomic shifts in Pelotomaculum thermopropionicum grown in syntrophic co-culture with Methanothermobacter thermautotrophicus.
Bottom Line: As it thrives on a very small energy conserved by propionate oxidation under syntrophic association with a methanogen, its catabolic pathways and regulatory mechanisms are of biological interest.Expression of the central catabolic pathway (the propionate-oxidizing methylmalonyl-CoA pathway) was found to be substrate-dependent and was largely stimulated when P. thermopropionicum was grown on propionate and lactate.These results revealed that P. thermopropionicum has complex regulatory mechanisms that alter its metabolism in response to the syntrophic partner and growth substrates.
Affiliation: Laboratory of Applied Microbiology, Marine Biotechnology Institute, Kamaishi, Iwate 026-0001, Japan.Show MeSH
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Mentions: Numbers of differentially expressed CDSs (at least twofold change with the P‐values of < 0.05) in the syntrophic co‐cultures by reference to those in the fumarate monoculture are summarized in Table 1. The numbers for the ethanol, 1‐propanol and lactate cultures [295 (10.2%), 383 (13.2%) and 358 (12.4%) CDSs, respectively, among the 2892 CDSs analysed] were not largely different, while substantially more CDSs were differentially expressed in the propionate culture [966 CDSs (33.4%)]. This indicates that the global cellular situation in the propionate co‐culture was largely different from that in the fumarate monoculture, which may have been related to the large difference in the growth rate. In order to systematically compare the global transcriptional responses in the syntrophic co‐cultures, a hierarchical cluster analysis was performed for the microarray data (Fig. 3). This analysis indicated that the expression profiles for ethanol and 1‐propanol culture were similar (r = 0.96), while those for the lactate and propionate cultures were relatively largely different.
Affiliation: Laboratory of Applied Microbiology, Marine Biotechnology Institute, Kamaishi, Iwate 026-0001, Japan.