Microbial Signalling And Communication

Presents information at the forefront of this exciting field and includes contributions on a range of organisms and signalling molecules.

Many bacterial diseases are caused by organisms growing together as communities or biofilms. These microorganisms have the capacity to coordinately regulate specific sets of genes by sensing and communicating amongst themselves utilizing a variety of signals. This book examines the mechanisms of quorum sensing and cell-to-cell communication in bacteria and the roles that these processes play in regulating virulence, bacterial interactions with host tissues, and microbial development. Recent studies suggest that microbial cell-to-cell communication plays an important role in the pathogenesis of a variety of disease processes. Furthermore, some bacterial signal molecules may possess immunomodulatory activity. Thus, understanding the mechanisms and outcomes of bacterial cell-to-cell communication has important implications for appreciating host-pathogen interactions and ultimately may provide new targets for antimicrobial therapies that block or interfere with these communication networks.

Providing a comprehensive insight into cellular signaling processes in bacteria with a special focus on biotechnological implications, this is the first book to cover intercellular as well as intracellular signaling and its relevance for biofilm formation, host pathogen interactions, symbiotic relationships, and photo- and chemotaxis. In addition, it deals in detail with principal bacterial signaling mechanisms -- making this a valuable resource for all advanced students in microbiology. Dr. Krämer is a world-renowned expert in intracellular signaling and its implications for biotechnology processes, while Dr. Jung is an expert on intercellular signaling and its relevance for biomedicine and agriculture.

It is generally assumed that microorganisms synthesize, release, detect and respond to small signaling hormone-like molecules. These molecules are used for a process termed “quorum sensing” (QS), a phenomenon that enables bacteria to sense when the minimal number of cells, or “quorum,” is achieved for a concerted response to be initiated. Words such as “language” and “behavior” are frequently used to depict QS in the literature. More simply put, language and cross-talk between bacteria, and between bacteria and animal or plant hosts, determines the behavior (e.g., beneficial or pathogenic effects) of bacteria. Currently, the major concern is to understand and decode this language. Overall, bacterial cross-talk was mainly studied on environmental, plant, and human pathogenic bacteria. Few studies considered food-related lactic acid bacteria. The cross-talk between bacteria influences the behavior and, in turn, the environmental adaptation and phenotypes. Therefore, it is understood that bacterial cross-talk has important applicative repercussions. The language spoken between bacteria populating the same food ecosystem may condition the phenotypic traits of starter lactic acid bacteria and, consequently, their performance. This Brief aims to define the basis of cell-to-cell signalling in food fermentation and will highlight: (i) microbiology, nutritional, chemical and functional aspects; (ii) functional properties due to microbial adaptation to the gastrointestinal tract; (iii) principal phenotypes under control of QS circuitries; (iv) quorum quenching. This Brief will be the first reference on this topic and it will highlight the main results for a more productive industrial application. Draft content 1. Signals of food related Gram-negative and Gram-positive bacteria The chapter will describe the different signaling languages used by Gram-negative bacteria (N-acyl-L-homoserine lactones) and Gram-positive bacteria (based on the synthesis of post-translationally modified peptides) and the universal chemical lexicon, shared by both Gram-positive and -negative bacteria (autoinducer-2 through the activity of the LuxS enzyme). 2. Phenotypes related to quorum sensing The chapter will describe the bacterial phenotypes, such as virulence, biofilm maturation, bacteriocin synthesis, and secondary metabolite production under control of QS circuitries. 3. Cell-to-cell signalling in fermented food: sourdough The chapter will describe the language spoken between bacteria populating the same food ecosystem (sourdough) and will provide an overview of the conditioned phenotypic traits of starter lactic acid bacteria and, consequently, their performance. 4. Cell-to-cell signalling in fermented food: yoghurt The chapter will describe the language spoken between bacteria populating the same food ecosystem (yoghurt) and will provide an overview of the conditioned phenotypic traits of starter lactic acid bacteria and, consequently, their performance. 5. Probiotic message at the intra-, inter-species and inter-kingdom level The chapter will describe the mechanisms that regulate the interaction between microorganism and host, and the capacity of the microorganism to adapt to environment. Particular reference will also be made to: (i) pathogen inhibition and restoration of microbial homeostasis through microbe-microbe interactions; (ii) enhancement of epithelial barrier function; and (iii) modulation of immune responses. 6. New Perspectives of quorum sensing This chapter will provide an overview of the future perspective regarding quorum sensing, showing that bacterial cross-talk may have important applicative repercussions. It will highlight the interference on the language of QS, which is defined as quorum quenching (QQ). Increasing translation of the bacterial cross-talk has shown that in some environmental circumstances, quenching of the language may occur.

Summarizes the science and recent research developments of chemical communication among bacteria

A multiplicity of biotrophic micro-organisms interact with plants in nature, forming symbiotic relationships that range from mutualism to antagonism. Microorganisms that have adopted biotrophy as a lifestyle are able to colonize the plant and often to cross the plant cell boundaries by forming intracellular structures that are the site of nutrient uptake/exchange. To establish themselves within plant tissues, both mutualistic and pathogenic biotrophs need to overcome the plant defense response through an exchange of molecular signals. Our knowledge of the nature of these signals and their function in the interaction has rapidly increased over the last few years. This volume focuses on the genetic, molecular and cellular components involved in the communication between partners of well-known symbioses, but also reports on the advances for less studied systems.

Communication is defined as an interaction between at least two living agents which share a repertoire of signs. These are combined according to syntactic, semantic and context-dependent, pragmatic rules in order to coordinate behavior. This volume deals with the important roles of soil bacteria in parasitic and symbiotic interactions with viruses, plants, animals and fungi. Starting with a general overview of the key levels of communication between bacteria, further reviews examine the various aspects of intracellular as well as intercellular biocommunication between soil microorganisms. This includes the various levels of biocommunication between phages and bacteria, between soil algae and bacteria, and between bacteria, fungi and plants in the rhizosphere, the role of plasmids and transposons, horizontal gene transfer, quorum sensing and quorum quenching, bacterial-host cohabitation, phage-mediated genetic exchange and soil viral ecology.