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Titolo:
Analysis of urease expression in Actinomyces naeslundii WVU45
Autore:
Morou-Bermudez, E; Burne, RA;
Indirizzi:
Univ Rochester, Sch Med & Dent, Dept Microbiol & Immunol, Rochester, NY 14642 USA Univ Rochester Rochester NY USA 14642 & Immunol, Rochester, NY 14642 USA Univ Rochester, Sch Med & Dent, Ctr Oral Biol, Rochester, NY USA Univ Rochester Rochester NY USA & Dent, Ctr Oral Biol, Rochester, NY USA
Titolo Testata:
INFECTION AND IMMUNITY
fascicolo: 12, volume: 68, anno: 2000,
pagine: 6670 - 6676
SICI:
0019-9567(200012)68:12<6670:AOUEIA>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
BACILLUS-SUBTILIS; DENTAL PLAQUE; STREPTOCOCCUS-SALIVARIUS; TRANSCRIPTIONAL ACTIVATORS; CONTINUOUS CULTURE; MICROBIAL UREASES; ESCHERICHIA-COLI; ORAL BACTERIA; GLNR GENE; NITROGEN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Burne, RA Univ Rochester, Sch Med & Dent, Dept Microbiol & Immunol, 601 Elmwood Ave,Rochester, NY 14642 USA Univ Rochester 601 Elmwood Ave Rochester NY USA 14642 14642 USA
Citazione:
E. Morou-Bermudez e R.A. Burne, "Analysis of urease expression in Actinomyces naeslundii WVU45", INFEC IMMUN, 68(12), 2000, pp. 6670-6676

Abstract

The hydrolysis of urea by ureases of oral bacteria in dental plaque can cause a considerable increase in plaque pH, which can inhibit the developmentof dental caries. There is also indirect evidence that urea metabolism maypromote the formation of calculus and that ammonia release from urea couldexacerbate periodontal diseases. Actinomyces naeslundii, an early colonizer of the oral cavity and a numerically significant plaque constituent, demonstrates comparatively low levels of urease activity on isolation, so this organism has not been considered a major contributor to total oral urease activity. In this study it was observed that urease activity and urease-specific mRNA levels in A. naeslundii WVU45 can increase up to 50-fold during growth under nitrogen-limiting conditions. Using primer extension analysis, a putative, proximal, nitrogen-regulated promoter of the A. naeslundii urease gene cluster was identified. The functionality and nitrogen responsiveness of this promoter were confirmed using reporter gene fusions and 5' deletion analysis. The data indicated that regulation of urease expression by nitrogen availability in A. naeslundii may require a positive transcriptionalactivator. Plaque bacteria may experience nitrogen limitation when carbohydrates are present in excess. Therefore, based on the results of this studyand in contrast to previous beliefs, strains of A. naeslundii may have thepotential to be significant contributors to total plaque ureolysis, particularly during periods when there is an increased risk for caries development.

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Documento generato il 26/01/21 alle ore 04:29:09