Chemical Interactions between Organisms in Microbial Communities

Abstract

Bacteria live almost exclusively in communities with other microorganisms, and often in association with multicellular hosts. These communities are capable of maintaining complex structural and functional stability over time, and exhibit fascinating properties of resiliency in response to environmental changes. This is a result of interactions between microbes and the environment and amongst members of the community. A multitude of chemical interactions occur in microbial communities where primary and secondary metabolites contribute to a wealth of interactions between organisms. The chemicals include a variety of nutrients, toxic or neutral metabolic byproducts, antibiotics, and cell-cell signaling molecules. These chemical and physical signals facilitate microbial relationship that can be competitive, cooperative or neutral, and thus are responsible for determining community structure. In turn, the surrounding community changes the microenvironment of individual cells who respond to chemical and environmental cues in a combinatorial manner. Current laboratory understanding of the genetics and mechanisms of interactions between microbes has the power to help us understand how complex microbial communities behave in the natural environment. In this chapter we review the current understanding of microbial communication, from the genetic and molecular aspects, to our current understanding of their ecological role.

Microbiology and Treatment of Acute Apical Abscesses

“…Increased diversity may be an important aspect of acute infections and collective pathogenicity, which is expected to be a result of the incalculable synergistic interactions among the community members and summation of virulence factors produced. It has been shown that every component of a polymicrobial infection, even species regarded as avirulent and/or in low numbers in the consortium, may somewhat affect the virulence of other members of the community (183)(184)(185)(186). Therefore, communication between bacterial community members can alter the production of virulence factors by certain pathogenic species and affect the collective pathogenicity of the consortium (185).…”

Sharing of quorum-sensing signals and role of interspecies communities in a bacterial plant disease

“…A transcriptional sensor/regulator belonging to the LuxR family then forms a complex with the cognate AHL at threshold ('quorum') concentrations thereby affecting the transcription of target genes (Fuqua et al, 2001). Bacteria in nature mostly grow as poly-microbial consortia, which most likely involve interspecies signaling through the action of diffusible signal molecules (Ryan and Dow, 2008;Duan et al, 2009). Understanding the signaling taking place in poly-bacterial communities will be a challenge for future studies as most investigations on QS thus far have involved mono-culture set-ups.…”

Evolutionary paths of electric oscillators

“…Одним из механизмов межклеточного взаимодействия прокариот является система, состоящая из белкового рецептора, чувстви-тельного к определенному сигналу, и регулятора ответа, который контролирует экспрес-сию нужных генов (Смольская, Песнякевич, 2006). В данном случае контроль регуляции генов осуществляется посредством небольших диффузионных молекул-феромонов (Duan et al, 2009). Такие сигнальные молекулы позволяют индивидуальным бактериальным клет-кам начать совместное действие тогда, когда будет достигнута пороговая плотность бакте-риальной популяции (кворум) (Lyon, 2007).…”