title: The regulatory effect of fermentable sugar levels on the production of leukotoxin by Actinobacillus actinomycetemcomitans.
abstract: The relationship between sugar availability and RTX (repeats in toxin) cytotoxin (leukotoxin) production in the periodontopathic bacterium, Actinobacillus actinomycetemcomitans, was investigated using a chemostat. A actinomycetemcomitans 301-b produced significant amounts of leukotoxin in anaerobic fructose-limited chemostat cultures at a dilution rate of 0.15 h-1 and at pH 7.0. When the growth limitation was relieved by pulsing the cultures with 50 or 150 mM fructose (final concentrations), leukotoxin production immediately stopped and the amount of cellular leukotoxin decreased until the culture was returned to fructose-limited conditions. Leukotoxin synthesis was also repressed in the chemostat cultures by pulsing with glucose but not with the non-fermentable sugar analog, alpha-methyl-D-glucoside. Leukotoxin production was also repressed by fructose in chemostat cultures of ATCC 33384, which is generally recognized as a non-leukotoxin-producing or minimally leukotoxic strain.
authors.affiliation: Department of Periodontology and Endodontology, Okayama University Dental School, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Mizoguchi
authors.forename: H
authors.initials: H
authors.lastname: Ohta
authors.forename: A
authors.initials: A
authors.lastname: Miyagi
authors.forename: H
authors.initials: H
authors.lastname: Kurihara
authors.forename: S
authors.initials: S
authors.lastname: Takashiba
authors.forename: K
authors.initials: K
authors.lastname: Kato
authors.forename: Y
authors.initials: Y
authors.lastname: Murayama
authors.forename: K
authors.initials: K
authors.lastname: Fukui
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000378:metabolism*; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000737:chemistry; D050260:Carbohydrate Metabolism; D005098:Exotoxins / Q000096:biosynthesis* / Q000737:chemistry; D005285:Fermentation; D007700:Kinetics; D008970:Molecular Weight
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins; C018579:leukotoxin