Regulation of biofilm formation by Pseudomonas chlororaphis in an in vitro system

Abstract

The mutants of Pseudomonas chlororaphis 449 with completely or partially suppressed accumula tion of N acyl homoserine lactones exhibited the absence or a pronounced decrease of their capacity for stim ulation of biofilm growth in the presence of azithromycin. Biofilms of the wild type strain preformed in the presence of the stimulatory azithromycin concentrations exhibited more intense staining with a polysaccha ride specific dye 1,9 dimethyl methylene blue (DMMB) and were more resistant to heat shock. These find ings indicate accumulation of the structural matrix polysaccharides, which play a protective role under con ditions of thermal shock. Extremely low azithromycin concentrations (0.001-0.01 µg/mL) inhibit biofilm formation by P. chlororaphis 449 and P. chlororaphis 66 with suppression of the synthesis of DMMB staining polysaccharides.

The Impact of Norepinephrine on Mono-Species and Dual-Species Staphylococcal Biofilms

“…A PTFE cube assay was used to compare mono-species planktonic and biofilm growth and to analyze the range of NE concentrations on bacteria. It was developed recently [ 17 , 18 , 19 ] and used in this work with modifications. Briefly, glass tubes were filled with cubes (21 chemically pure 4 × 4 × 4 mm PTFE cubes, Ftoroplast.…”

Bacterial biofilms in food processing environments: a review of recent developments in chemical and biological control

“…An example of how such change of expression in these genes can effect biofilm formation is a study of Pseudomonas chlororaphis mutants with completely or partially suppressed accumulation of acyl‐HSL. Those mutants with completely suppressed genes do not form biofilms, whereas those with partially suppressed genes form reduced biofilms (Gannesen et al ., ).…”

Epinephrine affects gene expression levels and has a complex effect on biofilm formation in Micrococcus luteus strain C01 isolated from human skin

“…Many compounds synthesized by human cells affect the microbiota, such as various humoral factors, hormones and neurotransmitters [ [15] , [16] , [17] , [18] ]. Biofilms are resistant to various antimicrobial agents, such as antibiotics, biocides and the host immune system/These properties are important in chronic infectious diseases [ 19 , 20 ], and skin biofilms are not an exception. Thus, it would be useful to searchnovel compounds with antibiofilm activities that do not cause resistance in pathogens.…”