Pic Protein From Enteroaggregative Induces Different Mechanisms for Its Dual Activity as a Mucus Secretagogue and a Mucinase.

A hallmark of enteroaggregative (EAEC) infection is the formation of an intestinal biofilm, which comprises a mucus layer with immersed bacteria. Pic is an autotransporter secreted by EAEC, and other pathotypes, and has been involved in two apparently contradictory phenotypes, as a mucus secretagogue and as a mucinase. Here, we investigated this Pic dual activity, mucus secretagogue capability and mucinolytic activity, in human goblet cells that secrete MUC2 and MUC5AC.

Nf-GH, a glycosidase secreted by Naegleria fowleri, causes mucin degradation: an in vitro and in vivo study.

Aim: The aim of this work was to identify, characterize and evaluate the pathogenic role of mucinolytic activity released by Naegleria fowleri.

Materials & Methods: Zymograms, protease inhibitors, anion exchange chromatography, MALDI-TOF-MS, enzymatic assays, Western blot, and confocal microscopy were used to identify and characterize a secreted mucinase; inhibition assays using antibodies, dot-blots and mouse survival tests were used to evaluate the mucinase as a virulence factor.

Results: A 94-kDa protein with mucinolytic activity was inducible and abolished by p-hydroxymercuribenzoate.