Contrary to the planktonic state of bacteria, their biofilm form represents severe complications in areas such as human medicine or food industry due to the increasing resistance against harsh conditions and treatment. In the present study, infrared attenuated total reflection (IR-ATR) spectroscopy has been applied as an analytic tool studying Escherichia coli ( E. coli) biofilm formation close to real time. We report on IR spectroscopic investigations on the biofilm formation via ATR waveguides probing the biofilm in the spectral window of 1800-900 cm-1 at dynamic flow conditions, which facilitated monitoring the growth dynamics during several days. Key IR bands are in the range 1700-1590 cm-1 (amide I), 1580-1490 cm-1 (amide II), and 1141-1006 cm-1 extracellular polymeric substances (EPS), which were evaluated as a function of time. Cyclic fluctuations of the amide I and amide II bands and a continuous increase of the EPS band were related to the starvation of bottom-layered bacteria caused by the nutrient gradient. Potential death of bacteria may then result in cannibalistic behavior known for E. coli colonies. Observing this behavior via IR spectroscopy allows revealing these cyclical changes in bottom-layered bacteria within the biofilm under continuous nutrient flow, in molecular detail, and during extended periods for the first time.
... and ATR Spectroscopy Monitors 9 the Dynamics of Proton Pumping Proteins -- C. ... ... V Fraile -- ÍXTable of Contents -- 9-^ ECSBM -- Structural Dynamics of Proteins -- ATR/FTIR Spectroscopy ... ... Fastermann, 1 Heberle -- A New Method Coupling Polarized ATR-FTIR Spectroscopy and iH/^H Exchange to ... ... Spectroscopy -- R. ... ... Barth -- Perfusion-Induced Differences in Cytochrome с Oxidase: ATR/FT-IR Studies 80 -- R. M. ...
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This study reports on the successful use of a machine learning approach using attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy for the classification and prediction of a donor's sex from the fingernails of 63 individuals. A significant advantage of ATR FT-IR is its ability to provide a specific spectral signature for different samples based on their biochemical composition. The infrared spectrum reveals unique vibrational features of a sample based on the different absorption frequencies of the individual functional groups. This technique is fast, simple, non-destructive, and requires only small quantities of measured material with minimal-to-no sample preparation. However, advanced multivariate techniques are needed to elucidate multiplex spectral information and the small differences caused by donor characteristics. We developed an analytical method using ATR FT-IR spectroscopy advanced with machine learning (ML) based on 63 donors' fingernails (37 males, 26 females). The PLS-DA and ANN models were established, and their generalization abilities were compared. Here, the PLS scores from the PLS-DA model were used for an artificial neural network (ANN) to create a classification model. The proposed ANN model showed a greater potential for predictions, and it was validated against an independent dataset, which resulted in 92% correctly classified spectra. The results of the study are quite impressive, with 100% accuracy achieved in correctly classifying donors as either male or female at the donor level. Here, we underscore the potential of ML algorithms to leverage the selectivity of ATR FT-IR spectroscopy and produce predictions along with information about the level of certainty in a scientifically defensible manner. This proof-of-concept study demonstrates the value of ATR FT-IR spectroscopy as a forensic tool to discriminate between male and female donors, which is significant for forensic applications.
- MeSH
- Algorithms * MeSH
- Humans MeSH
- Nails * MeSH
- Neural Networks, Computer MeSH
- Specimen Handling MeSH
- Spectroscopy, Fourier Transform Infrared methods MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Fully and partially hydrolyzed poly(vinyl alcohol) (PVA) was modified with zinc sulphate in the concentration range from 0 to 9 wt% of recalculated zinc content using the solvent cast technique. The resulting polymeric films were characterized by optical microscopy, stress-strain analysis, differential scanning calorimetry and Fourier transform infrared spectroscopy (FT-IR-ATR). In addition, agar diffusion test and dilution and spread plate technique were used for determination of antibacterial properties of the films against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) bacterial strains. A mathematical model was applied on the measured data and parameters characterizing the antibacterial efficiency of the material were calculated and discussed. The results revealed that the PVA hydrolysis degree can play an important role in all studied properties, including antibacterial activity of the all PVA-based materials.
- MeSH
- Anti-Bacterial Agents chemistry pharmacology MeSH
- Calorimetry, Differential Scanning MeSH
- Escherichia coli drug effects MeSH
- Hydrolysis MeSH
- Polymers chemistry pharmacology MeSH
- Polyvinyl Alcohol chemistry MeSH
- Pseudomonas aeruginosa drug effects MeSH
- Zinc Sulfate chemistry MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Staphylococcus aureus drug effects MeSH
- Models, Theoretical MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Biofilms are complex microbial communities that tend to attach to either biotic or abiotic surface. Enclosed in a self-produced extracellular polymeric substance (EPS) matrix, the biofilms often cause persistent infections. The objective of this study was to investigate the antibiofilm activity of dimethyl sulfoxide (DMSO) and afatinib against Gram-negative pathogens. Test microorganisms used in this study were Escherichia coli ATCC 1299, Pseudomonas aeruginosa ATCC 10145, and Salmonella typhimurium ATCC 14028. Biofilms were developed in 96-well microplate at 37°C for 24 h. Following removal of non-adherent cells, analysis of biofilm viability, biofilm biomass, and extracellular polymeric substances (EPS) matrix were performed using resazurin assay, crystal violet assay, and attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, respectively. Bradford protein assay was conducted to determine the total amount of EPS proteins. The results demonstrated that both 32% DMSO alone and its combination with 3.2 μg/mL afatinib were effective in killing biofilm cells and reducing biofilm biomass. IR spectral variations of EPS matrix of biofilms in the range between 1700 and 900 cm-1 were also observed. Reduction in EPS proteins verified the chemical modifications of EPS matrix. In conclusion, 32% DMSO alone and its combination with 3.2 μg/mL afatinib showed remarkable antibiofilm activities against Gram-negative pathogens. It was suggested that the biofilm inhibition was mediated by the chemical modification of EPS matrix.
- MeSH
- Anti-Bacterial Agents pharmacology MeSH
- Biofilms drug effects MeSH
- Quinazolines pharmacology MeSH
- Dimethyl Sulfoxide pharmacology MeSH
- Escherichia coli drug effects physiology MeSH
- Pseudomonas aeruginosa drug effects physiology MeSH
- Salmonella typhimurium drug effects physiology MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Drug Synergism MeSH
- Publication type
- Journal Article MeSH
