TY - JOUR
T1 - Indole
T2 - a signaling molecule or a mere metabolic byproduct that alters bacterial physiology at a high concentration?
AU - Kim, Jisun
AU - Park, Woojun
N1 - Publisher Copyright:
© 2015, The Microbiological Society of Korea and Springer-Verlag Berlin Heidelberg.
PY - 2015/7/29
Y1 - 2015/7/29
N2 - Indole is an organic compound that is widespread in microbial communities inhabiting diverse habitats, like the soil environment and human intestines. Measurement of indole production is a traditional method for the identification of microbial species. Escherichia coli can produce millimolar concentrations of indole in the stationary growth phase under nutrient-rich conditions. Indole has received considerable attention because of its remarkable effects on various biological functions of the microbial communities, for example, biofilm formation, motility, virulence, plasmid stability, and antibiotic resistance. Indole may function as an intercellular signaling molecule, like a quorum-sensing signal. Nevertheless, a receptor system for indole and the function of this compound in coordinated behavior of a microbial population (which are requirements for a true signaling molecule) have not yet been confirmed. Recent findings suggest that a long-known quorum-sensing regulator, E. coli’s SdiA, cannot recognize indole and that this compound may simply cause membrane disruption and energy reduction, which can lead to various changes in bacterial physiology including unstable folding of a quorum-sensing regulator. Indole appears to be responsible for acquisition of antibiotic resistance via the formation of persister cells and activation of an exporter. This review highlights and summarizes the current knowledge about indole as a multitrophic molecule among bacteria, together with recently identified new avenues of research.
AB - Indole is an organic compound that is widespread in microbial communities inhabiting diverse habitats, like the soil environment and human intestines. Measurement of indole production is a traditional method for the identification of microbial species. Escherichia coli can produce millimolar concentrations of indole in the stationary growth phase under nutrient-rich conditions. Indole has received considerable attention because of its remarkable effects on various biological functions of the microbial communities, for example, biofilm formation, motility, virulence, plasmid stability, and antibiotic resistance. Indole may function as an intercellular signaling molecule, like a quorum-sensing signal. Nevertheless, a receptor system for indole and the function of this compound in coordinated behavior of a microbial population (which are requirements for a true signaling molecule) have not yet been confirmed. Recent findings suggest that a long-known quorum-sensing regulator, E. coli’s SdiA, cannot recognize indole and that this compound may simply cause membrane disruption and energy reduction, which can lead to various changes in bacterial physiology including unstable folding of a quorum-sensing regulator. Indole appears to be responsible for acquisition of antibiotic resistance via the formation of persister cells and activation of an exporter. This review highlights and summarizes the current knowledge about indole as a multitrophic molecule among bacteria, together with recently identified new avenues of research.
KW - SdiA
KW - antibiotic resistance
KW - indole
KW - protein folding
KW - quorum sensing
KW - signaling
UR - http://www.scopus.com/inward/record.url?scp=84932614326&partnerID=8YFLogxK
U2 - 10.1007/s12275-015-5273-3
DO - 10.1007/s12275-015-5273-3
M3 - Review article
C2 - 26115989
AN - SCOPUS:84932614326
SN - 1225-8873
VL - 53
SP - 421
EP - 428
JO - Journal of Microbiology
JF - Journal of Microbiology
IS - 7
ER -