Characterization and heterologous expression of plasmalogen synthase MeHAD from Megasphaera elsdenii.

Plasmalogens (Pls) are vinyl-ether bond-containing glycerophospholipids or glycosyl diradyl glycerols, and are of great importance in the physiological functions and stability of cell membrane. Here, we identified and characterized that the plasmalogen synthase MeHAD from anaerobic Megasphaera elsdenii was responsible for vinyl-ether bond formation. Different from the 2-hydroxyacyl-CoA dehydratase (HAD) family plasmalogen synthase PlsA-PlsR which are encoded by two genes in Clostridium perfringens, the HAD homolog (MeHAD) encoded by a single gene MELS_0169 was found in M.

HexSDF Is Required for Synthesis of a Novel Glycolipid That Mediates Daptomycin and Bacitracin Resistance in C. difficile.

Clostridioides difficile is a Gram-positive opportunistic pathogen responsible for 250,000 hospital-associated infections, 12,000 hospital-associated deaths, and $1 billion in medical costs in the United States each year. There has been recent interest in using a daptomycin analog, surotomycin, to treat C. difficile infections.

Plasmalogens in bacteria, sixty years on.

The presence of plasmalogens in bacteria has been known for 60 years. The recent discovery of two genes encoding reductases that convert diacyl lipids to 1-alk-1'-enyl 2-acyl lipids has confirmed the derivation of plasmalogens from the corresponding diacyl lipids in bacteria. These genes are widely distributed in anaerobic and in some facultatively anaerobic bacteria.

Cyclopropane Fatty Acids Are Important for Serovar Typhimurium Virulence.

A variety of eubacteria, plants, and protozoa can modify membrane lipids by cyclopropanation, which is reported to modulate membrane permeability and fluidity. The ability to cyclopropanate membrane lipids has been associated with resistance to oxidative stress in Mycobacterium tuberculosis, organic solvent stress in Escherichia coli, and acid stress in E. coli and Salmonella.

Lipid diversity in clostridia.

Studies of the lipidomes of twenty-one species of clostridia have revealed considerable diversity. Even among those species now defined as Clostridium sensu stricto, which are related to Clostridium butyricum, the type species, lipid analysis has shown that a number of distinct clades have characteristic polar lipids. All species of Clostridium sensu stricto have phosphatidylethanolamine, phosphatidylglycerol and cardiolipin which are present as all acyl or alk-1'-enyl acyl (plasmalogen) species.