January 1, 2015.
Bacterial biofilms play a critical role in inducing and sustaining chronic wounds that are serious health threats. Bacterial biofilms can also be found on medical prosthetics and implants that sustain infections in patients and cause life threatening situations. Bacteria self-produce these sticky extracellular substances termed a biofilm which help them to adhere to each other forming a community of microorganisms. One of the major issues is that biofilms have antimicrobial characteristics and provide protection from the immune system; biofilms are found in over 80% of human bacterial infections. Formation of a bacterial biofilm occurs when an individual (planktonic) bacterial cell attaches to a surface such as collagen exposed in a wound. The planktonic bacterial cell then converts into a biofilm phenotype which allows it to grow and divide on the surface thereby forming layers of microcolonies. After maturation, which is characterized by the production of an extracellular matrix, cells detach from the biofilm and disperse to re-enter the planktonic mode and repeat the biofilm cycle. Under conditions of stress, namely injury or disease, the human body releases adrenaline-like hormones called catecholamines such as epinephrine (adrenaline) and norepinephrine (noradrenaline). Many studies have indicated a close relationship between the presence of catecholamine hormones in a human host and the growth, formation, and virulence of bacterial biofilms. Furthermore, studies from Dr. Isseroff’s dermatology lab at UC Davis confirm that the presence of these catecholamines at dermal wound sites impair the healing process by generating a cellular response through activation of beta-adrenergic receptors. However, few species of bacterial biofilms have been shown to produce catecholamines independently, and none have been shown to produce epinephrine. We examined two species of bacteria commonly found in chronic wounds, Pseudomonas aeruginosa(Gram negative) and Staphylococcus aureus (Gram positive), to determine whether they can produce catecholamines in eukaryotic cell growth conditions. We examined the supernatants of the media after the bacteria were cultured with 0% and 10% concentrations of Adult Bovine Serum (ABS) and then detected for the presence of catecholamines by High Pressure Liquid Chromatography Electrochemical Detection (HPLC-ED).
Hormones, Hormone Substitutes, and Hormone Antagonists
Dr. Thomas Peavy
California State University, Sacramento (Sac State)
This material is based upon work supported by the S.D. Bechtel Jr. Foundation and is made possible with contributions from the National Science Foundation under Grant No. 1340110, Howard Hughes Medical Institute, Chevron Corporation, National Marine Sanctuary Foundation, and from the host research center. Any opinions, findings, and conclusions or recommendations expressed in this material are solely those of the authors. The STAR Program is administered by the Cal Poly Center for Excellence in STEM Education on behalf of the California State University system.
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