The possibility of incorporating N-acetylneuraminic acid (Neu5Ac) in infant formulas and other functional foods has opened up the need to synthesize N-acetylneuraminic acid using N-acetylneuraminate lyases (NALs) by reversible aldol condensation of pyruvate and N-acetyl-d-mannosamine. Until now, NALs have been cloned from pathogenic microorganisms; however, this Article describes the expression and characterization of an N-acetylneuraminate lyase from the Staphylococcus carnosus TM300, a GRAS microorganism used in fermented meat. ScNAL showed a high level of expression in E. coli (403 mg L–1 culture). This, combined with its simple two-step purification procedure, the highest recovery described to date (86%), its kinetic parameters, which are in the same order of magnitude as best reported NALs, and its optimum pH and temperature, make ScNAL a promising and cheap biocatalyst. To confirm its biotechnological potential, the Neu5Ac was synthesized in 3 h in simple industrial working conditions with a high degree of conversion (94%).

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The in vitro activities of amoxicillin, cefuroxime, ceftetrame, cefetamet, cefixime, tigemonam, erythromycin, roxithromycin, and dirithromycin against 30 clinical isolates of Campylobacter pylori were determined by an agar dilution technique. Roxithromycin and amoxicihlin (MICs for 90% of isolates tested, 0.01 and 0.06 ,ug/ml, respectively) were the most active antibiotics tested, but all strains were susceptible to all antimicrobial agents tested.Since Marshall and Warren detected and isolated Campylobacter pylori from gastric mucosa (9, 17), the role of this bacterium in the pathogenesis of gastroduodenal lesions has been controversial (7,15).It has been suggested that C. pylori colonization is secondary to damage of the gastroduodenal mucosa by other factors (W. L. Peterson, E. L. Lee, and M. Feldman, Gastroenterology 90:1585, 1986), but several studies indicated a close association between both chronic gastritis and peptic ulcer and C. pylori (1,4,16). Clearance of microorganisms with amoxicillin or bismuth salts that leads to resolution of gastritis has been demonstrated (8; M. L.