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Biofilm growth is associated with an escalated level of mutations and horizontal gene transfer which is promoted in due to the packed and dense structure. Bacteria in biofilms communicate by quorum sensing, which activates genes participating in virulence factors production. [25] [26] Biofilms are the product of a microbial developmental ...
Quorum sensing (QS) is used by bacteria to form biofilms. Quorum sensing is used by bacteria to form biofilms because the process determines if the minimum number of bacteria necessary for biofilm formation are present. The criteria to form a biofilm is dependent on a certain density of bacteria rather than a certain number of bacteria being ...
Since the cell wall is required for bacterial survival, but is absent in some eukaryotes, several antibiotics (notably the penicillins and cephalosporins) stop bacterial infections by interfering with cell wall synthesis, while having no effects on human cells which have no cell wall, only a cell membrane.
Biofilms are a way for S. pyogenes, as well as other bacterial cells, to communicate with each other. In the biofilm gene expression for multiple purposes (such as defending against the host immune system) is controlled via quorum sensing. [34] One of the biofilm forming pathways in GAS is the Rgg2/3 pathway.
Because biofilms protect the bacteria, they are often more resistant to traditional antimicrobial treatments, making them a serious health risk. [1] For example, there are more than one million cases of catheter-associated urinary tract infections (CAUTI) reported each year, many of which can be attributed to bacterial biofilms. [2]
Most of the bacterial species found in the mouth belong to microbial communities, called biofilms, a feature of which is inter-bacterial communication. Cell–cell contact is mediated by specific protein adhesins and often, as in the case of inter-species aggregation, by complementary polysaccharide receptors. Another method of communication ...
Some bacteria, such as Streptococcus pyogenes, Staphylococcus aureus and Pseudomonas aeruginosa, produce a variety of enzymes which cause damage to host tissues.Enzymes include hyaluronidase, which breaks down the connective tissue component hyaluronic acid; a range of proteases and lipases; DNases, which break down DNA, and hemolysins which break down a variety of host cells, including red ...
Dispersin B is produced by Aggregatibacter actinomycetemcomitans, a Gram-negative oral bacterium, when it needs to detach and disperse adherent bacterial cells. [4] A. actinomycetemcomitans forms asymmetric biofilm lobed colonies that release single cells or small clusters of bacterial cells, which can attach to nearby surfaces, form new colonies, and enable the biofilm to spread.