The Phospholipid N-Methyltransferase and Phosphatidylcholine Synthase Pathways and the ChoXWV Choline Uptake System Involved in Phosphatidylcholine Synthesis Are Widely Conserved in Most, but Not All Brucella Species

Abstract

The brucellae are facultative intracellular bacteria with a cell envelope rich in phosphatidylcholine (PC). PC is abundant in eukaryotes but rare in prokaryotes, and it has been proposed that Brucella uses PC to mimic eukaryotic-like features and avoid innate immune responses in the host. Two PC synthesis pathways are known in prokaryotes: the PmtA-catalyzed trimethylation of phosphatidylethanolamine and the direct linkage of choline to CDP-diacylglycerol catalyzed by the PC synthase Pcs. Previous studies have reported that B. abortus and B. melitensis possess non-functional PmtAs and that PC is synthesized exclusively via Pcs in these strains. A putative choline transporter ChoXWV has also been linked to PC synthesis in B. abortus. Here, we report that Pcs and Pmt pathways are active in B. suis biovar 2 and that a bioinformatics analysis of Brucella genomes suggests that PmtA is only inactivated in B. abortus and B. melitensis strains. We also show that ChoXWV is active in B. suis biovar 2 and conserved in all brucellae except B. canis and B. inopinata. Unexpectedly, the experimentally verified ChoXWV dysfunction in B. canis did not abrogate PC synthesis in a PmtA-deficient mutant, which suggests the presence of an unknown mechanism for obtaining choline for the Pcs pathway in Brucella. We also found that ChoXWV dysfunction did not cause attenuation in B. suis biovar 2. The results of these studies are discussed with respect to the proposed role of PC in Brucella virulence and how differential use of the Pmt and Pcs pathways may influence the interactions of these bacteria with their mammalian hosts.

High microbiome and metabolome diversification in coexisting sponges with different bio-ecological traits

“…In C. nucula negative associations with DG seem to co-occur also with extracellular symbionts. These include Oligoflexaceae, an extracellular partner taxon in corals 121 , and Synechoccocus spongiarium 122 , which had also negative association with MePC, phosphatidylcholine derivatives typical of eukaryote membranes, and reported in intracellular bacteria to avoid host immune responses 123 . Instead, HCO36, UBA10353 and TK17 microbes were positively related with DG, being TK17 also correlated with MePC.…”

Metabolomics profiling reveals berberine-inhibited inflammatory response in human gingival fibroblasts by regulating the LPS-induced apoptosis signaling pathway

“…Ceramide is the key metabolite of sphingomyelin metabolism. Its biological functions primarily include inducing apoptosis ( Toshima et al, 2019 ; Partoazar et al, 2021 ), regulating cell differentiation ( Naeini et al, 2021 ), regulating cellular immunity, and participating in regulating inflammatory response ( Aragón-Aranda et al, 2021 ). Our results revealed that berberine could significantly decrease LysoPC levels, which indicated that berberine could significantly prevent LPS-induced systemic inflammation by regulating the abnormal phospholipid metabolic pathway.…”

Pseudochrobactrum algeriensis sp. nov., isolated from lymph nodes of Algerian cattle

“…This indicates that the phospholipid methyltransferase (PmtA) pathway is active. Although the PmtA pathway was proposed to be a trait distinguishing the Pseudochrobactrum and Ochrobactrum clades from Brucella [ 1 ], it has been recently shown that some Brucella species have an active PmtA pathway and thus produce PMME and PDME [ 20 ], in contrast to B. abortus and B. melitensis where PMME and PDME are not or barely detectable [ 21, 22 ].…”