Fibroblast growth-stimulating activity of S100A9 (MRP-14).

Fibroblasts play a critical role in chronic inflammation and wound healing. In this study, a fibroblast growth-stimulating factor was purified from the exudate of carrageenan-induced inflammation in rats. The purified protein was a disulfide-linked homodimer. Amino acid sequence analysis of the peptides generated by cleavage with cyanogen bromide and proteinase V8 resulted in identification of the protein as S100A9. Recombinant S100A9 as well as its disulfide-linked homodimer stimulated the proliferation of fibroblasts at a similar concentration of the purified protein. The concentration of S100A9 in the exudate was determined by immunoblot analysis. The total protein concentration in the exudate reached a maximum 4 days after carrageenan injection and then slightly decreased, whereas the concentration of S100A9 reached a maximum at day 3 and then decreased rapidly. These studies show that S100A9 is present at a high concentration in the exudate of carrageenan-induced inflammation in rats, and that S100A9 stimulates proliferation of fibroblasts, suggesting that it plays a role in chronic inflammation.     

Emulsions Stabilization and Lipid Digestion Profiles of Sodium Alginate Microgels: Effect of the Crosslink Density

Food Biophysics - In this research, microgels with different crosslink density were prepared using the hydrophilic sodium alginate (ALG), and the interfacial adsorption, emulsion formation and...     

Mutational deglycosylation of the Fc portion of immunoglobulin G causes O-sulfation of tyrosine adjacently preceding the originally glycosylated site

Mutagenesis directed to a specific glycosylation site has been widely used to examine biological roles of individual glycans. However, occurrence of any post-translational modification on such deglycosylated mutants has not yet been well characterized. Here we performed mass spectrometric analyses of the Fc fragment of an unglycosylated mutant of mouse immunoglobulin G2b, whose conserved N-glycosylation site, i.e. Asn297, was substituted with alanine. We found that a major part of this mutant is sulfated at Tyr296, which adjacently precedes the originally glycosylated site. Our findings demonstrate that mutational deglycosylation can induce an unexpected post-translational modification in the protein.     

Microtropiosides A–F: ent-Labdane diterpenoid glucosides from the leaves of Microtropis japonica (Celastraceae)

From a 1-BuOH-soluble fraction of a MeOH extract of the leaves of Microtropis japonica, collected in the Okinawa islands, six ent-labdane glucosides, named microtropiosides A–F, were isolated together with one known acyclic sesquiterpene glucoside. Their structures were elucidated by a combination of spectroscopic analyses, and their absolute configurations determined by application of the β-d-glucopyranosylation-induced shift-trend rule in ¹³C NMR spectroscopy and the modified Mosher’s method.