Bacterial Stress Responses

Gain new insight on utilizing bacterial stress responses to better combat bacterial infection with antibiotics and improve biotechnology. • Reviews the vast number of new findings that have greatly advanced the understanding of bacterial stress responses in the past 10 years. • Explores general regulatory principles, including the latest findings from genomics studies, including new research findings on both specific and general stress responses. • Details how stress responses affect the interactions between bacteria and host cells and covers bacterial stress responses in different niches and communities, with an emphasis on extreme environments.

Bacteria in various habitats are subject to continuously changing environmental conditions, such as nutrient deprivation, heat and cold stress, UV radiation, oxidative stress, dessication, acid stress, nitrosative stress, cell envelope stress, heavy metal exposure, osmotic stress, and others. In order to survive, they have to respond to these conditions by adapting their physiology through sometimes drastic changes in gene expression. In addition they may adapt by changing their morphology, forming biofilms, fruiting bodies or spores, filaments, Viable But Not Culturable (VBNC) cells or moving away from stress compounds via chemotaxis. Changes in gene expression constitute the main component of the bacterial response to stress and environmental changes, and involve a myriad of different mechanisms, including (alternative) sigma factors, bi- or tri-component regulatory systems, small non-coding RNA’s, chaperones, CHRIS-Cas systems, DNA repair, toxin-antitoxin systems, the stringent response, efflux pumps, alarmones, and modulation of the cell envelope or membranes, to name a few. Many regulatory elements are conserved in different bacteria; however there are endless variations on the theme and novel elements of gene regulation in bacteria inhabiting particular environments are constantly being discovered. Especially in (pathogenic) bacteria colonizing the human body a plethora of bacterial responses to innate stresses such as pH, reactive nitrogen and oxygen species and antibiotic stress are being described. An attempt is made to not only cover model systems but give a broad overview of the stress-responsive regulatory systems in a variety of bacteria, including medically important bacteria, where elucidation of certain aspects of these systems could lead to treatment strategies of the pathogens. Many of the regulatory systems being uncovered are specific, but there is also considerable “cross-talk” between different circuits. Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria is a comprehensive two-volume work bringing together both review and original research articles on key topics in stress and environmental control of gene expression in bacteria. Volume One contains key overview chapters, as well as content on one/two/three component regulatory systems and stress responses, sigma factors and stress responses, small non-coding RNAs and stress responses, toxin-antitoxin systems and stress responses, stringent response to stress, responses to UV irradiation, SOS and double stranded systems repair systems and stress, adaptation to both oxidative and osmotic stress, and desiccation tolerance and drought stress. Volume Two covers heat shock responses, chaperonins and stress, cold shock responses, adaptation to acid stress, nitrosative stress, and envelope stress, as well as iron homeostasis, metal resistance, quorum sensing, chemotaxis and biofilm formation, and viable but not culturable (VBNC) cells. Covering the full breadth of current stress and environmental control of gene expression studies and expanding it towards future advances in the field, these two volumes are a one-stop reference for (non) medical molecular geneticists interested in gene regulation under stress.

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The Cover Image for This Research Topic is Used With Permission of the Authors and Publishers of the Following Article: Winkler J, Seybert A, König L, Pruggnaller S, Haselmann U, Sourjik V, Weiss M, Frangakis AS, Mogk A, Bukau B.EMBO J. 2010 Mar 3;29(5):910-23. doi: 10.1038/emboj.2009.412. Epub 2010 Jan 21

Food-borne bacterial pathogens encounter a number of stressors during food processing and preservation. More and more pathogens are able to adapt their physiological properties and/or genetic expression to survive these stressors and pose a risk to food safety and public health. This book provides the reader with a comprehensive overview of common food processing-associated stressors (e.g., heat, cold, acid, osmosis, and oxidation) and deals with the molecular basis of the respective bacterial stress response mechanisms (e.g., viable but nonculturable state, biofilm formation, sporulation, and cross-protection response). Additionally, various chapters cover the response mechanisms of foodborne pathogens to emerging nonthermal sterilisation technologies such as ultrasound, high-pressure processing, pulsed electric fields, ultraviolet light, irradiation and phytochemicals. Through this book we also learn about future prospects for the efficient control of stress adaption in foodborne pathogens to ensure maximum consumer safety. This book offers a valuable resource for researchers, graduate students, food process engineers and product developers in the fields of food science and microbiology.

Throughout the food processing chain and after ingestion by the host, food associated bacteria have to cope with a range of stress factors such as thermal and/or non-thermal inactivation treatments, refrigeration temperatures, freeze-drying, high osmolarity, acid pH in the stomach or presence of bile salts in the intestine, that threaten bacterial survival. The accompanying plethora of microbial response and adaptation phenomena elicited by these stresses has important implications for food technology and safety. Indeed, while resistance development of pathogenic and spoilage microorganisms may impose health risks for the consumer and impart great economic losses to food industries, reduced survival of probiotic bacteria may strongly compromise their claimed health benefit attributes. As a result, substantial research efforts have been devoted in the last decades to unravel the mechanisms underlying stress response and resistance development in food associated microorganisms in order to better predict and improve (i) the inactivation of foodborne pathogens and spoilage microorganisms on the one hand and (ii) the robustness and performance of beneficial microorganisms on the other. Moreover, the recent implementation of system-wide omics and (single-)cell biology approaches is greatly boosting our insights into the modes of action underlying microbial inactivation and survival. This Research Topic aims to provide an avenue for dissemination of recent advances within the field of microbial stress response and adaptation, with a particular focus not only on food spoilage and pathogenic microorganisms but also on beneficial microbes in foods.

Beginning with the basics of lactic acid bacteria and stress response, then working into specific fields of research and current developments, Stress Responses of Lactic Acid Bacteria will serve as an essential guidebook to researchers in the field, industry professionals, and advanced students in the area. The exploration of stress responses in lactic acid bacteria began in the early 90s and revealed the differences that exist between LAB and the classical model microorganisms. A considerable amount of work has been performed on the main genera / species of LAB regarding the genes implicated and their actual role and regulation, and the mechanisms of stress resistance have also been elucidated. Recent genome and transcriptome analyses complement the proteome and genetic information available today and shed a new light on the perception of and the responses to stress by lactic acid bacteria.

Foods fermented with lactic acid bacteria are an important part of the human diet. Lactic acid bacteria play an essential role in the preservation of food raw materials and contribute to the nutritional, organoleptic, and health properties of food products and animal feed. The importance of lactic acid bacteria in the production of foods throughout the world has resulted in a continued scientific interest in these micro-organisms over the last two decades by academic research groups as well as by industry. This research has resulted in a number of important scientific breakthroughs and has led to new applications. The most recent of these advances is the establishment of the complete genome sequences of a number of different lactic acid bacterial species. To communicate and stimulate the research on lactic acid bacteria and their applications, a series of tri-annual symposia on lactic acid bacteria was started in 1983 under the auspices of the Netherlands Society for Microbiology (NVVM), which was later also supported by the Federation of European Microbiological Societies (FEMS). The aim of these state-of-the-art symposia is to offer a unique platform for universities, institutes, and industry in this area of biotechnology, to present recent work, to obtain information on new developments, and to exchange views with colleagues from all over the world on scientific progress and applications. The growing number of participants at these symposia has been a clear demonstration of the interest of the international industrial and scientific community in this area of research. The 7th Symposium is based on a number of plenary lectures that review the scientific progress of the last years in the different areas of research on lactic acid bacteria, and which are documented in this special issue of Antonie van Leeuwenhoek.