Results-Reduction-Lfchimera-Chx-Control-h

In contrast, MH at concentration up to 100 µM did not inhibit biofilm formation. The ratio of live/dead bacteria in biofilm was also significantly lower after 15 min exposure to 20 µM of LFchimera compared to control and 20-50 µM of CHX and MH. Altogether, the results obtained indicate that LFchimera is able to inhibit in vitro subgingival biofilm formation and reduce viability of multispecies bacteria in biofilm better than Antibacterial activity of chensinin-1b, a peptide with a random coil conformation, against multiple-drug-resistant Pseudomonas aeruginosa. Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Nosocomial infections caused by Pseudomonas aeruginosa are difficult to treat due to the low permeability of its outer membrane as well as to its remarkable ability to acquire further resistance to antibiotics. Chensinin-1b exhibited antibacterial activity against the tested multiple-drug-resistant bacteria with However, the MIC (25μM) of chensinin-1b to multiple-drug-resistant P. aeruginosa strain (MRPA 0108) was 16-fold higher than that observed to P.

aeruginosa susceptible strain CGMCC 160 (PA1860). Chensinin-1b was able to disturb the integration of the cytoplasmic membrane of PA1860 and MRPA0108 cells similarly, but the outer membrane permeability of MRPA0108 cells was significantly lower. This low permeability was associated with increased expression of lipopolysaccharide (LPS) in the outer membrane and a decrease in negatively charged phospholipids in the outer membrane leaflet. In addition, the biofilm of MRPA0108 was responsible for the reduced susceptibility to chensinin-1b. A higher concentration of chensinin-1b (12µM) was required to maximally inhibit the formation of MRPA0108 biofilm. Notably, chensinin-1b inhibited the formation of MRPA0108 biofilm at concentrations below its MIC value by down-regulating the a significant antibacterial effect against MRPA0108 in vivo. Administration of chensinin-1b to mice infected with MRPA 0108 significantly increased survival by 50-70%.

Moreover, chensinin-1b reduced the production of pro-inflammatory mediators and correspondingly reduced lung and liver tissue damage in the mouse model of septic shock induced by MRPA 0108. Collectively, Colanic acid polymer suggest that chensinin-1b could be an effective antibiotic against multiple-drug-resistant bacterial strains. SinR is a mutational target for fine-tuning biofilm formation in laboratory-evolved strains of Bacillus subtilis. BACKGROUND: Bacteria often form multicellular, organized communities known as biofilms, which protect cells from a variety of environmental stresses. During biofilm formation, bacteria secrete a species-specific matrix; in Bacillus subtilis biofilms, the matrix consists of protein polymers and exopolysaccharide. Many domesticated strains of B. subtilis have a reduced ability to form biofilms, and we conducted a two-month evolution experiment to test whether laboratory culturing provides selective pressure against biofilm RESULTS: Bacteria grown in two-month-long batch culture rapidly diversified their biofilm-forming characteristics, exhibiting highly diverse colony morphologies on LB plates in the initial ten days of culture.

Generally, Colanic acid polymer decreased over time; however, multiple types of colony morphology remained in our final two-month-old populations, both under shaking and static conditions. Notably, while our final populations featured cells that produce less biofilm matrix than did the ancestor, cells overproducing biofilm matrix were present as well. We took a candidate-gene approach to identify mutations in the strains that overproduced matrix and found point mutations in the biofilm-regulatory gene sinR. Introducing these mutations into the ancestral strain phenocopied or partially phenocopied the evolved biofilm phenotypes. CONCLUSIONS: Our data suggest that standard laboratory culturing conditions do not rapidly select against biofilm formation. Although biofilm matrix production is often reduced in domesticated bacterial strains, we found that matrix production may still have a fitness benefit in the laboratory. We suggest that adaptive specialization of biofilm-forming species can occur through mutations that modulate biofilm formation as in B.

subtilis. Kinetics of biofilm formation by drinking water isolated Penicillium expansum. Current knowledge on drinking water (DW) biofilms has been obtained mainly from studies on bacterial biofilms. Very few reports on filamentous fungi (ff) biofilms are available, although they can contribute to the reduction in DW quality.