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Single Bacterial Cells (single + bacterial_cell)
Selected AbstractsQuorum sensing: the power of cooperation in the world of PseudomonasENVIRONMENTAL MICROBIOLOGY, Issue 4 2005Mario Juhas Summary Work over the past few years has provided evidence that quorum sensing is a generic regulatory mechanism that allows bacteria to launch a unified, coordinated response in a population density-dependent manner to accomplish tasks which would be difficult, if not impossible, to achieve for a single bacterial cell. Quorum sensing systems are widespread among pseudomonads and the one of the human opportunistic pathogen Pseudomonas aeruginosa belongs to the most extensively studied cell-to-cell communication systems. In this organism, quorum sensing is highly complex and is made up of two interlinked N- acyl homoserine lactone (AHL)-dependent regulatory circuits, which are further modulated by a non-AHL-related signal molecule and numerous regulators acting both at the transcriptional and post-transcriptional level. This genetic complexity may be one of the key elements responsible for the tremendous environmental versatility of P. aeruginosa. Work of the past few years showed that quorum sensing is essential for the expression of a battery of virulence factors as well as for biofilm formation in P. aeruginosa and thus represents an attractive target for the design of novel drugs for the treatment of P. aeruginosa infections. Furthermore, the cell-to-cell communication ability was also demonstrated in a number of additional pseudomonads. [source] Direct analysis of clinical relevant single bacterial cells from cerebrospinal fluid during bacterial meningitis by means of micro-Raman spectroscopyJOURNAL OF BIOPHOTONICS, Issue 1-2 2009Michaela Harz Abstract Bacterial meningitis is a relevant public health concern. Despite the availability of modern treatment strategies it is still a life-threatening disease that causes significant morbidity and mortality. Therefore, an initial treatment approach plays an important role. For in-time identification of specific bacterial pathogens of the cerebrospinal fluid (CSF) and emerged antimicrobial and adjunctive treatment, microbiological examination is of major importance. This contribution spotlights the potential of micro-Raman spectroscopy as a biomedical assay for direct analysis of bacteria in cerebrospinal fluid of patients with bacterial meningitis. The influence of miscellaneous artificial environments on several bacterial species present during bacterial meningitis was studied by means of Raman spectroscopy. The application of chemometric data interpretation via hierarchical cluster analysis (HCA) allows for the differentiation of in vitro cultured bacterial cells and can also be achieved on a single cell level. Moreover as proof of principle the investigation of a CSF sample obtained from a patient with meningococcal meningitis showed that the cerebrospinal fluid matrix does not mask the Raman spectrum of a bacterial cell notably since via chemometric analysis with HCA an identification of N. meningitidis cells from patients with bacterial meningitis could be achieved. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Detection of bacteria aided by immuno-nanoparticlesJOURNAL OF RAMAN SPECTROSCOPY, Issue 11 2007Ghinwa Naja Abstract Magnetic immuno-nanorice particles were used for the capture and detection of Escherichia coli (E. coli) bacteria. The selectivity of the method was attained by attaching a specific anti- E. coli antibody on the surface of the nanorice, binding exclusively to E. coli. The antibody attachment to the nanorice (60% sorption efficiency) took place through protein-A molecules (82% uptake). Once E. coli was captured, the immuno-nanorice-bacteria complex was separated from the solution using the magnetic property of the nanorice. The detection of bacteria sorbed onto the immuno-nanorice was accomplished using the ultra-violet resonance Raman (UVRR) method, detecting single bacterial cells. Specific information concerning the aromatic residues tyrosine (Tyr), phenylalanine (Phe) and tryptophan (Trp) was derived. The discriminant function and cluster hierarchical analysis confirmed the specific and reliable bacteria-detection capabilities. Copyright © 2007 John Wiley & Sons, Ltd. [source] Numbers and transported state of Escherichia coli in runoff direct from fresh cowpats under simulated rainfall,LETTERS IN APPLIED MICROBIOLOGY, Issue 2 2006R.W. Muirhead Abstract Aims:, To investigate the number of Escherichia coli in runoff derived directly from fresh cowpats and to determine if the E. coli are attached to dense particles, in flocs or as individual cells. Methods and Results:, Three cowpats were collected monthly from the same farm for 13 months and the number of E. coli in them estimated. A rainfall simulator was used to generate runoff from the individual cowpats, which was fractioned to determine the transported state of any E. coli present. The number of E. coli in the cowpat runoff was highly variable and was strongly correlated with the number of E. coli in the cowpat. Only a small percentage (approx. 8%) of the E. coli in runoff were attached to dense (>1·3 g ml,1) particles and there was no evidence of flocculation of the cells. Conclusions:,Escherichia coli in runoff from cowpats are transported predominantly as individual cells. Significance and Impact of the Study:, Mitigation strategies to reduce the number of faecal bacteria in overland flow from agricultural land need to be designed to trap single bacterial cells. [source] | ||||||||||