title: Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria.
abstract: Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera - Vibrio cholerae О1 - is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6-5.8.
authors.affiliation: a The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, 26 Acad. G. Bonchev Str, 1113 Sofia, Bulgaria.
authors.forename: Rumyana
authors.initials: R
authors.lastname: Eneva
authors.forename: Stephan
authors.initials: S
authors.lastname: Engibarov
authors.forename: Tanya
authors.initials: T
authors.lastname: Strateva
authors.forename: Radoslav
authors.initials: R
authors.lastname: Abrashev
authors.forename: Ignat
authors.initials: I
authors.lastname: Abrashev
mesh_terms: D002031:Bulgaria; D009439:Neuraminidase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D044163:Vibrio cholerae non-O1 / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D014871:Water Microbiology
chemical_list: D009439:Neuraminidase