The contribution of cell-cell signaling and motility to bacterial biofilm formation.
ABSTRACT Many bacteria grow attached to a surface as biofilms. Several factors dictate biofilm formation, including responses by the colonizing bacteria to their environment. Here we review how bacteria use cell-cell signaling (also called quorum sensing) and motility during biofilm formation. Specifically, we describe quorum sensing and surface motility exhibited by the bacterium Pseudomonas aeruginosa, a ubiquitous environmental organism that acts as an opportunistic human pathogen in immunocompromised individuals. P. aeruginosa uses acyl-homoserine lactone signals during quorum sensing to synchronize gene expression important to the production of polysaccharides, rhamnolipid, and other virulence factors. Surface motility affects the assembly and architecture of biofilms, and some aspects of motility are also influenced by quorum sensing. While some genes and their function are specific to P. aeruginosa, many aspects of biofilm development can be used as a model system to understand how bacteria differentially colonize surfaces.
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ABSTRACT: Bacterial cell-to-cell signalling has emerged as a new area in microbiology. Individual bacterial cells communicate with each other and co-ordinate group activities. Although a lot of detail is known about the mechanisms of a few well-characterized bacterial communication systems, other systems have been discovered only recently. Bacterial intercellular communication has become a target for the development of new anti-virulence drugs.Nature Reviews Molecular Cell Biology 10/2002; 3(9):685-95. · 39.12 Impact Factor
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ABSTRACT: To obtain data on mesothelioma incidence in Central and Eastern Europe, a short questionnaire was sent to 83 researchers from 19 countries. The questions referred to the approximate number of mesotheliomas diagnosed per year in the country, degree of asbestos consumption, and percentage of lung carcinomas attributable to asbestos. Answers were received from 12 countries. For some major asbestos producers and/or consumers, such as Russia and Ukraine, mesothelioma data were unavailable or unreliable. In various countries of Central-Eastern Europe, the crude incidence of mesothelioma appeared to be lower than in Western countries. The reported annual numbers of mesotheliomas were 120 in Poland, 133 in Romania, and 78 in Hungary. Among the countries with a population of 5 million or less, the highest incidence was observed in Croatia (46 cases per year, peritoneal tumors not included). Data on the percentage of asbestos-related lung carcinomas are lacking. The knowledge about asbestos related cancer in Central and Eastern Europe remains fragmentary. Further investigations in this relevant area of public health should be encouraged.Acta medica Croatica: c̆asopis Hravatske akademije medicinskih znanosti 02/2000; 54(4-5):161-4.
Article: Quorum-sensing genes in Pseudomonas aeruginosa biofilms: their role and expression patterns.[show abstract] [hide abstract]
ABSTRACT: Acylated homoserine lactone molecules are used by a number of gram-negative bacteria to regulate cell density-dependent gene expression by a mechanism known as quorum sensing (QS). In Pseudomonas aeruginosa, QS or cell-to-cell signaling controls expression of a number of virulence factors, as well as biofilm differentiation. In this study, we investigated the role played by the las and rhl QS systems during the early stages of static biofilm formation when cells are adhering to a surface and forming microcolonies. These studies revealed a marked difference in biofilm formation between the PAO1 parent and the QS mutants when glucose, but not citrate, was used as the sole carbon source. To further elucidate the contribution of lasI and rhlI to biofilm maturation, we utilized fusions to unstable green fluorescent protein in concert with confocal microscopy to perform real-time temporal and spatial studies of these genes in a flowing environment. During the course of 8-day biofilm development, lasI expression was found to progressively decrease over time. Conversely, rhlI expression remained steady throughout biofilm development but occurred in a lower percentage of cells. Spatial analysis revealed that lasI and rhlI were maximally expressed in cells located at the substratum and that expression decreased with increasing biofilm height. Because QS was shown previously to be involved in biofilm differentiation, these findings have important implications for the design of biofilm prevention and eradication strategies.Applied and Environmental Microbiology 05/2001; 67(4):1865-73. · 3.83 Impact Factor