Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Regulation mechanisms underlying the biosynthesis of daptomycin and related lipopeptides

Daptomycin is a lipopeptide antibiotics used to treat Gram-positive pathogens infections, including drug-resistant strains. In-depth exploration of its biosynthesis and regulation is crucial for metabolic engineering improvement of this ever-increasing important antibiotic. The past years have witnessed the significant progresses in the understanding of the molecular mechanisms underlying the biosynthesis and regulation of daptomycin. This information was updated in our review, with special focus on the regulatory network integrating a wide variety of physiological and environmental inputs. This should provide novel insight into the regulatory mechanism of biosynthesis of daptomycin and nodes for strain improvement to increase the yields of daptomycin.     

Structure and function of mycobacterium glycopeptidolipids from comparative genomics perspective

Glycopeptidolipids (GPLs) attached to the outer surface of the greasy cell envelope, are a class of important glycolipids synthesized by several non‐tuberculosis mycobacteria. The deletion or structure change of GPLs confers several phenotypical changes including colony morphology, hydrophobicity, aggregation, sliding motility, and biofilm formation. In addition, GPLs, particular serovar specific GPLs, are important immunomodulators. This review aims to summarize the advance on the structure, function and biosynthesis of mycobacterium GPLs. J. Cell. Biochem. 114: 1705–1713, 2013. © 2013 Wiley Periodicals, Inc.