Journal of Microbial & Biochemical Technology

Characterisation of extracellular DNA in Listeria monocytogenes biofilm with the use of fluorescent techniques

Joint Event on 4^th World Congress and Expo on Applied Microbiology & 2^nd International Conference on Food Microbiology

November 29-December 01, 2017 Madrid, Spain

Martina Bohacova, Demnerova K and Pazlarova J

University of Chemistry and Technology, Prague, Czech Republic

Posters & Accepted Abstracts: J Microb Biochem Technol

Abstract:

Extracellular DNA (eDNA) is an abundant matrix component that protects biofilm from the environmental stress, facilitate the horizontal gene transfer and serve as source of nutrients. eDNA is also found in Listeria monocytogenes biofilm, but it is unknown to which extent its importance as a matrix component varies from strain to strain. This study aims to determine if strain-specific variations exist, and if the role of eDNA in L. monocytogenes biofilms is dependent on the conditions under which the biofilm was formed. Biofilm forming capacity of 10 selected Listeria monocytogenes strains originating from food of different phylogenetic lineages and serotypes was examined using crystal violet assay. The strains were cultured under static condition in nutrient rich environment at 37 �°C, and in low nutrient environment at ambient temperature. Biofilm forming capacity was evaluated by crystal violet assay, and the 3D structure of biofilm was studied by fluorescence staining and confocal microscopy. Extracellular DNA was quantified by PicoGreen�® staining and fluorometric detection. Significant differences in biofilm forming capacity were found between the culturing conditions. There was a positive correlation between extracellular DNA production and total biomass under both culturing conditions and the significant difference was shown in extracellular DNA release between the conditions. Although extracellular DNA concentration was affected by biomass, confocal laser scanning microscopy (CLSM) images revealed information about spatial distribution in biofilm. Extracellular DNA signal distribution was found to be influenced by strain and lineage. Recent Publications 1. Flemming H C and Wingender J (2010) The biofilm matrix. Nat Rev Microbiol 8(9):623-33. 2. Guilbaud M, et al. (2015) Exploring the diversity of listeria monocytogenes biofilm architecture by high-throughput confocal laser scanning microscopy and the predominance of the honeycomb-like morphotype. Applied and Environmental Microbiology 81(5):1804-1810. 3. Kadam S R, et al. (2013) Diversity assessment of Listeria monocytogenes biofilm formation: Impact of growth condition, serotype and strain origin. Int J Food Microbiol 165(3):259-264. 4. Okshevsky M and Meyer R L (2013) The role of extracellular DNA in the establishment, maintenance and perpetuation of bacterial biofilms. Crit Rev Microbiol. 33:73-80. 5. Tang L, et al. (2013) Extracellular DNA in adhesion and biofilm formation of four environmental isolates: a quantitative study. FEMS Microbiol Ecol. 86:394â��403.

Biography :

Martina Bohacova is a PhD student in Microbiology who is studying biofilm matrix dynamics in L. monocytogenes biofilms. Currently, she is gaining experience with fluorescence based techniques like confocal laser scanning microscopy, general statistic methods, image analysis and risk assessment in food microbiology.