Search results for "BIOFILM"

Inhibitors of antibiotic resistance mechanisms: clinical applications and future perspectives

2020

Bacterial strains responsible for antibiotic resistant infections are increasing in an alarming way and the evolution of resistance mechanisms seems to be unstoppable. In the past decade, many efforts have been made in order to counteract this phenomenon but very few compounds have reached clinical trials. The development of new classes of antibiotics able to overcome the main bacterial drug resistance mechanisms is urgently required to counter the imminent danger of a postantibiotic era.

Shedding light on biogas: Phototrophic biofilms in anaerobic digesters hold potential for improved biogas production

2019

Conventional anaerobic digesters intended for the production of biogas usually operate in complete darkness. Therefore, little is known about the effect of light on their microbial communities. In the present work, 16S rRNA gene amplicon Nanopore sequencing and shotgun metagenomic sequencing were used to study the taxonomic and functional structure of the microbial community forming a biofilm on the inner wall of a laboratory-scale transparent anaerobic biodigester illuminated with natural sunlight. The biofilm was composed of microorganisms involved in the four metabolic processes needed for biogas production, and it was surprisingly rich in Rhodopseudomonas faecalis, a versatile bacterium…

Bifunctional dentifrice: Amorphous polyphosphate a regeneratively active sealant with potent anti- Streptococcus mutans activity

2017

Abstract Objective In this study we demonstrate that inorganic polyphosphate (polyP) exhibits a dual protective effect on teeth: it elicits a strong antibacterial effect against the cariogenic bacterium Streptococcus mutans and, in form of amorphous calcium polyP microparticles (size of 100–400 nm), it efficiently reseals cracks/fissures in the tooth enamel and dentin. Methods Three different formulations of amorphous polyP microparticles (Ca-polyP, Zn-polyP and Sr-polyP) were prepared. Results Among the different polyP microparticles tested, the Ca-polyP microparticles, as a component of a newly developed formulation of a dentifrice, turned out to be most effective in inhibiting growth of …

Multiple-stressor effects on river biofilms under different hydrological conditions

2016

Summary We studied the relative importance of environmental factors (river flow, nutrients, dissolved organic matter) and organic micro-pollutants [herbicides, insecticides, industrial organic compounds, personal care products, antibiotics and pharmaceuticals, (PhCs)] to the structure and function of epilithic biofilms under various hydrological conditions and land uses. Biofilms from four river basins in the Iberian Peninsula (Llobregat, Ebro, Jucar and Guadalquivir) were analysed in summer–autumn during a wet period and base-flow conditions. The sites experienced different levels of pollution. We used variance partitioning (Redundancy Detrended Analysis, RDA) to link environmental stresso…

Microbial Adaptation to Boreal Saturated Subsurface: Implications in Bioremediation of Polychlorophenols

2008

Saturated subsurface environments pose challenges to the intrinsic microbiology. Prevailing environmental conditions (temperature, pH, bioavailability of substrates and nutrients) affect microbial biodegradation activity, which is often favored by certain redox conditions. Microbial adaptation in each redox environment proceeds by selection and enrichment of indigenous bacteria, evolution of novel catabolic pathways and horizontal gene transfer (Wilson et al. 1985; van der Meer et al. 1998; Tiirola et al. 2002b). Formation of biofilms enables microbial retainment, co-operation among microorganisms and enhanced gene transfer among organisms (Singh et al. 2006). Chlorophenols are toxic and pe…

Total mercury and methyl-mercury contents and accumulation in polar microbial mats.

2014

Although polar regions are considered isolated and pristine areas, the organisms that inhabit these zones are exposed to global pollution. Heavy metals, such as mercury, are global pollutants and can reach almost any location on Earth. Mercury may come from natural, volcanic or geological sources, or result from anthropogenic sources, in particular industrial or mining activities. In this study, we have investigated one of the most prominent biological non-marine communities in both polar regions, microbial mats, in terms of their Hg and methyl-mercury (MeHg) concentrations and accumulation capacities. The main hypotheses posed argued on the importance of different factors, and to test them…

TOWARD POTENT ANTIBIOFILM DEGRADABLE MEDICAL DEVICES: GENERIC METHODOLOGIES FOR THE SURFACE MODIfiCATION OF POLYLACTIDE

2014

When Functionalization of PLA Surfaces Meets Thiol−Yne Photochemistry: Case Study with Antibacterial PolyaspartamideDerivatives

2014

International audience; In this work we wish to report on the covalent functionalization of polylactide (PLA) surfaces by photoradical thiol–yne to yield antibacterial surfaces. At first, hydrophilic and hydrophobic thiol fluorescent probes are synthesized and used to study and optimize the conditions of ligation on alkyne-PLA surfaces. In a second part, a new antibacterial polyaspartamide copolymer is covalently grafted. The covalent surface modification and the density of surface functionalization are evaluated by SEC and XPS analyses. No degradation of PLA chains is observed, whereas covalent grafting is confirmed by the presence of S2p and N1s signals. Antiadherence and antibiofilm acti…

Modeling in Microbial Ecology

2014

SPE IPM; International audience; The bases and the principles of modeling in microbial community ecology and biogeochemistry are presented and discussed. Several examples are given. Among them, the fermentation process is largely developed, thus demonstrating how the model allows determining the microbial population growth rate, the death rate, and the maintenance rate. More generally, these models have been used to increase the development of bioenergetic formulations which are presently used in biogeochemical models (Monod, Droop, DEB models). Different types of interactions (competition, predation, and virus–bacteria) are also developed. For each topic, a complete view of the models used…

Association of colony morphotypes with virulence, growth and resistance against protozoan predation in the fish pathogen Flavobacterium columnare.

2014

Many opportunistic pathogens can alternate between inside- and outside-host environments during their life cycle. The opportunistic fish pathogen Flavobacterium columnare is an inhabitant of the natural microbial community and causes significant yearly losses in aquaculture worldwide. The bacterium grows in varying colony morphotypes that are associated with either virulence (rhizoid type) or resistance to starvation and phages (rough type). Rough type strains can arise spontaneously or can be induced by phage infection. To identify the determinants of morphotype fitness, we measured virulence, growth parameters, biofilm-forming ability and resistance to amoeba and ciliate predation of both…