Using Fourier Transform Infrared (FT-IR) Absorbance Spectroscopy and Multivariate Analysis To Study the Effect of Chlorine-Induced Bacterial Injury in Water
| Autor: | Hamzah M. Al-Qadiri, Murad A. Al-Holy, Barbara Rasco, Nivin Al-Alami |
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| Rok vydání: | 2008 |
| Předmět: |
Colony Count
Microbial chemistry.chemical_element Infrared spectroscopy medicine.disease_cause Absorbance Cell wall chemistry.chemical_compound Spectroscopy Fourier Transform Infrared Escherichia coli polycyclic compounds Chlorine medicine Fourier transform infrared spectroscopy Chromatography Bacteria biology Water General Chemistry biology.organism_classification chemistry Multivariate Analysis Pseudomonas aeruginosa Peptidoglycan Water Microbiology General Agricultural and Biological Sciences |
| Zdroj: | Journal of Agricultural and Food Chemistry. 56:8992-8997 |
| ISSN: | 1520-5118 0021-8561 |
| DOI: | 10.1021/jf801604p |
| Popis: | The effect of chlorine-induced bacterial injury on spectral features using Fourier transform infrared (FT-IR) absorbance spectroscopy was studied using a mixed bacterial culture of (1:1) ca. 500 CFU/mL each Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 15442 in 0.9% saline. Bacterial cells were treated with 0, 0.3, or 1.0 ppm of initial free chlorine (21 degrees C, 1 h of contact time). Chlorine-injured and dead bacterial cells retained the ATR spectral properties of uninjured or live cells in the region of C-O-C stretching vibrations of polysaccharides, indicative of the cell wall peptidoglycan layer and lipopolysaccharide outer leaflet. This confirms the observations of others that extensive bacterial membrane damage is not a key factor in the inactivation of bacteria by chlorine. The bactericidal effect of chlorine caused changes in the spectral features of bacterial ester functional groups of lipids, structural proteins, and nucleic acids, with apparent denaturation reflected between 1800 and 1300 cm (-1) for injured bacterial cells. Three-dimensional principal component analysis (PCA) showed distinct segregation and clustering of chlorine-treated and untreated cells. Cells exposed to chlorine at 0.3 or 1.0 ppm could be distinguished from the untreated control 73 and 80% of the time, respectively, using soft independent modeling of class analogy (SIMCA) analysis. This study suggests that FT-IR spectroscopy may be applicable for detecting the presence of injured and viable but not culturable (VBNC) waterborne pathogens that are underestimated or not discernible using conventional microbial techniques. |
| Databáze: | OpenAIRE |
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