Characterization of the biofilm matrix composition of psychrotrophic, meat spoilage pseudomonads

Abstract

Psychrotrophic Pseudomonas species are the key spoilage bacteria of aerobically stored chilled meat. These organisms readily form biofilms on meat under refrigerated conditions leading to consumer rejection and associated economic losses. Limited information is available on the matrix composition of the biofilms formed by these bacteria. We quantified and characterized the main components of the matrix of mono-species biofilms of selected Pseudomonas fragi and Pseudomonas lundensis strains using chemical analysis and Raman spectroscopy. The biofilms were grown at 10 °C and 25 °C on nitro-cellulose membranes placed on surface sterilized beef cuts. Extra-cellular polymeric substances of the matrix were extracted in soluble and bound forms and were chemically assessed for total carbohydrates, proteins and extra-cellular DNA. Both Pseudomonas species showed a significant increase in total carbohydrates and total proteins when grown at 10 °C as compared to 25 °C. Extra-cellular DNA did not show a strong correlation with growth temperature. Raman spectra were obtained from planktonic bacteria and membrane grown biofilms at 10 °C and 25 °C. Higher levels of guanine were detected in planktonic cells as compared to biofilm cells. This study suggests that psychrotrophic Pseudomonas species may respond to cold stress by increasing extra-cellular polymer secretions.

Antibacterial Mechanism of Dellaglioa algida against Pseudomonas fluorescens and Pseudomonas fragi

“…Suppression During the Development Stage: In the experiments on the influence of various concentrations, including 0 MIC, 0.5 MIC, 1 MIC, and 2 MIC, of the CFS of D. algida on the capability of generation and growth of biofilm, the crystal violet staining method was utilized, where the approach to assay was inspired by [26][27][28]. Under the pathogen-free condition, stationary bacteria solution of 200 µL was put into a 96-well cell culture plate and cultured at 28 • C, while the TSB medium was utilized as blank control.…”

Microporous Multiresonant Plasmonic Meshes by Hierarchical Micro–Nanoimprinting for Bio‐Interfaced SERS Imaging and Nonlinear Nano‐Optics

“…[ 44,45 ] As the biofilm develops from 6 to 48 h, the peak for nucleic acids (968 cm –1 ) decreases in intensity, while several peaks associated with biofilm extracellular polymeric substance (EPS) [ 46 ] proteins (638, 822, 1180, 1240, 1366), carbohydrates (858 and 1140 cm –1 ), and lipids (1305 and 1444 cm –1 ) emerge. [ 47,48 ] These observations reflect that mesh SERS hotspot arrays experience increased exposure to EPS components (e.g., polysaccharides and proteins) and reduced exposure to the cell membrane and eDNA components during the biofilm formation and growth process. In this scenario, the increasing depth of the EPS layer within the biofilm may limit access of the buried cells and eDNA components to the SERS hotspots in the mesh sensors.…”

Microbial Biofilms: Structural Plasticity and Emerging Properties

“…The extracellular matrix contains a complex panel of chemically diverse molecules with various roles in biofilm development, architecture, and functions, also termed the matrixome [2]. This matrixome is highly dependent on species diversity and environmental conditions in terms of composition [3,4]. It cements cells together and highly participates in the shaping and the plasticity of biofilm spatial organization, resulting in a great diversity of biofilm architectures [5,6].…”