Microbial Ecology in States of Health and Disease Workshop Summary (2014) / Chapter Skim
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A21 Antimicrobial peptides and the microbiome--Michael Zasloff
A21 Antimicrobial peptides and the microbiome--Michael Zasloff
Pages 489-496
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From page 489... ...
The skin of this amphibian, like that of other frogs, is invested with granular glands, neuroendocrine structures that synthesize at least a dozen antimicrobial peptides, along with proteins that create a hydrophobic gel on the skin surface when the gland discharges its contents. The wound is subsequently covered with a hydrophobic salve containing a cocktail of antimicrobial peptides at a concentration about 50–100 fold greater than required to kill all micro-organisms that might interfere with healing (Zasloff, 1987)
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From page 490... ...
It is likely that continuous low level discharge of the widely distributed granular glands maintains a relatively restricted diversity of resistant bacteria on its skin. In addition, several of the amphibian skin commensals are known to themselves secrete antimicrobial agents that must act to further reduce species diversity (Harris, 2006)
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From page 491... ...
If either organism is applied to the surface of unwashed human adult skin, within several minutes these bacteria die. If an antibody that inactivates either of the antimicrobial proteins is applied to the skin prior to application of bacteria, the corresponding microbes remain viable on the skin (Glaser et al., 2005; Koten et al., 2009)
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From page 492... ...
Few, if any microorganisms can normally be seen microscopically in fluids sampled from a healthy human airway. The epithelial lining of the normal human airway distal to the trachea is covered by a micron-thick fluid layer secreted by the underlying cells.
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From page 493... ...
In the small ntestine, specialized Paneth i cells that lie at the base of the crypts, secrete high concentrations of a cocktail of antimicrobial peptides and proteins that flood the overlying surface fluid layer. As a consequence of the mucous barrier, the bactericidal submucous fluid layer, and the rapid regeneration of the epithelial layer, bacteria generally cannot gain a foothold on the epithelial surface, nor invade the layer and enter the lamina propria.
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From page 494... ...
The ability of humans to coexist with environmental microbes and to support a diverse microbiome is in part a consequence of the existence of antimicrobial peptides and proteins. The antimicrobial barrier is generally clinically "silent" in states of health, creating a chemical barrier without the need for a degree of inflammation that we recognize clinically by the classic signs of "redness, heat, and swelling." At the same time, these substances exert selective pressure on the organisms that comprise our microbiome, influencing microbial ecology.
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From page 495... ...
1996. Cystic fibrosis airway epithelia fail to kill bacteria because of abnormal airway surface fluid.
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From page 496... ...
2012. Microbiome dynamics of human epidermis following skin barrier disruption.
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