The discovery of stress-induced mutagenesis has changed ideas about mutation and evolution, and revealed mutagenic programs that differ from standard spontaneous mutagenesis in rapidly proliferating cells. The stress-induced mutations occur during growth-limiting stress, and can include adaptive mutations that allow growth in the otherwise growth-limiting environment. The stress responses increase mutagenesis specifically when cells are maladapted to their environments, i.e. are stressed, potentially accelerating evolution then. The mutation mechanism also includes temporary suspension of post-synthesis mismatch repair, resembling mutagenesis characteristic of some cancers. Stress-induced mutation mechanisms may provide important models for genome instability underlying some cancers and genetic diseases, resistance to chemotherapeutic and antibiotic drugs, pathogenicity of microbes, and many other important evolutionary processes. This book covers pathways of stress-induced mutagenesis in all systems. The principle focus is mammalian systems, but much of what is known of these pathways comes from non-mammalian systems.

Concerted efforts to study starvation and survival of nondifferentiating vegeta tive heterotrophic bacteria have been made with various degrees of intensity, in different bacteria and contexts, over more than the last 30 years. As with bacterial growth in natural ecosystem conditions, these research efforts have been intermittent, with rather long periods of limited or no production in between. While several important and well-received reviews and proceedings on the topic of this monograph have been published during the last three to four decades, the last few years have seen a marked increase in reviews on starvation survival in non-spore-forming bacteria. This increase reflects a realization that the biology of bacteria in natural conditions is generally not that of logarithmic growth and that we have very limited information on the physiology of the energy-and nutrient-limited phases of the life cyde of the bacterial cello The growing interest in nongrowing bacteria also sterns from the more recent advances on the molecular basis of the starvation-induced nongrowing bacterial cello The identification of starvation-specific gene and protein re sponders in Escherichia coli as weIl as other bacterial species has provided molecular handles for our attempts to decipher the "differentiation-like" responses and programs that nondifferentiating bacteria exhibit on nutrient limited growth arrest. Severallaboratories have contributed greatly to the progress made in life after-log research.

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.

An "age" has passed in the 40 years since we first observed recovery from radiation damage in irradiated bacteria. During the early 1930s, we had been discussing the possibility of rapid changes after radiation exposure with Farring ton Daniels, Benjamin Duggar, John Curtis, and others at the University of Wisconsin. After working with living cells, we had concluded that organisms receiving massive insults must have a wide variety of repair mechanisms available for restoration of at least some of the essential properties of the cell. The problem was how to fmd and identify these recovery phenomena. At that time I was working on a problem considered to be of great importance-the existence of the so-called mitogenetic rays. Several hundred articles and a score of books had already appeared dealing with mitogenetic rays, a type of radiation that was thought to exist in the shorter ultraviolet region. Our search for mitogenetic rays necessitated the design of experiments of greatest sensitivity for the detection of ultraviolet. It was vital that conditions be kept as constant as possible during exposure. All the work was done at icewater temperature (3-5°C) during and after exposure. We knew that light was an important factor for cell recovery, so all our experiments were done in dim light, with the plated-out cells being covered with dark cloth. Our statements on the effect of visible light stimulated Kelner to search for "photoreactivation' (as it was later called).

Publisher Description

Most organisms and populations have to cope with hostile environments, threatening their existence. Their ability to respond phenotypically and genetically to these challenges and to evolve adaptive mechanisms is, therefore, crucial. The contributions to this book aim at understanding, from a evolutionary perspective, the impact of stress on biological systems. Scientists, applying different approaches spanning from the molecular and the protein level to individuals, populations and ecosystems, explore how organisms adapt to extreme environments, how stress changes genetic structure and affects life histories, how organisms cope with thermal stress through acclimation, and how environmental and genetic stress induce fluctuating asymmetry, shape selection pressure and cause extinction of populations. Finally, it discusses the role of stress in evolutionary change, from stress induced mutations and selection to speciation and evolution at the geological time scale. The book contains reviews and novel scientific results on the subject. It will be of interest to both researchers and graduate students and may serve as a text for graduate courses.

The DNA of all organisms is constantly being damaged by endogenous and exogenous sources. Oxygen metabolism generates reactive species that can damage DNA, proteins and other organic compounds in living cells. Exogenous sources include ionizing and ultraviolet radiations, carcinogenic compounds and environmental toxins among others. The discovery of multiple DNA lesions and DNA repair mechanisms showed the involvement of DNA damage and DNA repair in the pathogenesis of many human diseases, most notably cancer. These books provide a comprehensive overview of the interdisciplinary area of DNA damage and DNA repair, and their relevance to disease pathology. Edited by recognised leaders in the field, this two-volume set is an appealing resource to a variety of readers including chemists, chemical biologists, geneticists, cancer researchers and drug discovery scientists.

Abstract: This book presents contemporary information on mutagenesis in plants and its applications in plant breeding and research. The topics are classified into sections focusing on the concepts, historical development and genetic basis of plant mutation breeding (chapters 1-6); mutagens and induced mutagenesis (chapters 7-13); mutation induction and mutant development (chapters 14-23); mutation breeding (chapters 24-34); or mutations in functional genomics (chapters 35-41). This book is an essential reference for those who are conducting research on mutagenesis as an approach to improving or modifying a trait, or achieving basic understanding of a pathway for a trait --.