Biofilms of research in anything from mechanics,
Biofilms surroundus in the environment and therefore make up an important topic of research inanything from mechanics, health and disease, to understanding how natureinteracts.
Biofilms consist of a group of species specific, or nonspecific,bacteria that adhere to one another by secretion of an extracellular polymericsubstance, a sticky substance made up of sugars, DNA or protein. Many aspectsof cell-to-cell communication are required not only in the initial biofilmformation but in maintaining the integrity of the colony throughout its lifetime.Bacterial cells must initially recognize the circumstances of its environment,and the abundance of other cells in its proximity. Eventually they must come incontact with one another and/or to a surface before they can begin multiplyingand differentiating. Depending on the alternation of strains of bacteria, cellsutilize various forms of communication and response mechanisms in the formationof biofilms.Biofilm adherenceand formation in common gram-negative bacteria differs slightly from oneanother. Essentially, biofilms play a critical role in antibiotic resistanceand host cell infection.
In terms of EscherichiaColi, cell colonies respond to autoinducers to successfully invade tissueby the creation of specific Type I fimbrae. This alteration in morphologyallows the pathogenic bacteria to migrate and adhere to one another, as well asto the mannose receptors spanning the host cell. Lectin is another sugarpolymer critical to biofilm productivity and cell-to-cell interaction.
Fluorescentlylabeled lectin has been used to prove biofilm regulation on the biogenesis ofthese polysaccharides making up the extracellular matrix. Gram-negative Pseudomonas Aeruginosa is known to haveto two essential lectin binding proteins. In response to quorum sensingmechanisms such as las or rhl, P.
Aeruginosa can alter their gene expression creating a chemical gradientthroughout the colony, thus dedicating a subset of cells to monitoring PELexopolysaccharide secretion, as well as the synthesis of the DNA component ofthe extracellular matrix. In addition to autoinducors, Pseudomonas also responds to other signal molecules including lowdosage antibiotics and pigments.