title: [Extracellular protease as a reversible adhesion regulator in Pseudomonas fluorescens].
abstract: The investigation of growth dynamics and protein content in a batch Pseudomonas fluorescens culture grown in a synthetic medium with glucose as the sole source of carbon and energy showed that cells reversibly adhere to the walls of the cultivation flask during the first 2-3 h of growth. Over this time period, the total protein content of free and bound cells increased exponentially at a rate of 0.25 h-1, the fraction of proteins in cells being almost the same (60-70%). The protein content in the medium increased from 3 to 50 mg/l, reaching about 30% of the total protein of the culture. The addition of the exponential culture liquid filtrate to the medium together with the inoculum led to the complete inhibition of cell adhesion and a drastic activation of proteolysis, with a concurrent release of more than 80% of cellular proteins into the medium. After 3-5 h of growth, the concentration of extracellular proteins decreased to the control level. Exogenously added proteinase K inhibited cell adhesion, the effect being more pronounced for R-type than for S-type cells. The hypothesis is discussed that the short-term reversible adhesion of cells is regulated with the involvement of a mixture of hydrocarbons, which inactivate the functional activity of bacterial adhesins, and proteases, which digest these adhesins.
authors.affiliation: Institute of Microbiology, Russian Academy of Sciences, pr. 60-letiya Oktyabrya 7, k. 2, Moscow, 117811 Russia.
authors.forename: Iu A
authors.initials: IuA
authors.lastname: Nikolaev
authors.forename: N S
authors.initials: NS
authors.lastname: Panikov
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism; D001422:Bacterial Adhesion / Q000187:drug effects*; D001426:Bacterial Proteins / Q000032:analysis / Q000096:biosynthesis; D017077:Culture Media, Conditioned; D019286:Endopeptidase K / Q000494:pharmacology*; D005947:Glucose; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D019286:Endopeptidase K; D005947:Glucose