BIOL 2303 Lecture Notes - Lecture 16: Biofouling, Bradyrhizobium, Motility
2 Nov 2020
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Document Summary
Assemblage of microbial cells attached to a surface and encased in adhesive polysaccharides excreted by the cells. Can be single species or multispecies (bacteria and archaea) Mode of growth for most prokaryotes in natural environments. Develop only in areas of sufficient nutrients: examples: Cathethers, iud"s pacemakers: plaque on teeth, biofouling of pipes, rhizosphere and other plant surfaces. Confocal scanning laser micrographs of a developing pseudomonas aeruginosa biofilm. Motile cells become less sessile (non- motile) Up regulation of genes involved in capsule biosynthesis. Access to nutrients: traps nutrients from the environment, retains material secreted by microbes in the biofilm, promotes coordinated use of nutrients by different species. Protection: from predators/grazers- protozoa, macrophage, from chemicals- antibiotics, disinfectants. Allows for the development of micro-niches: gradients of ph, oxygen, nutrients. Being cells into close proximity for conjugation. P. auruginose- biofilm formation in human lungs- difficult to treat infection, biofilm assists in making bacteria antibiotic resistant and helping them persist in the infected individual.
