Microbial Evolution Under Extreme Conditions

Today's microorganisms represent the vast majority of biodiversity on Earth and have survived nearly 4 billion years of evolutionary change. However, we still know little about the processes of evolution as applied to microorganisms and microbial populations. Microbial evolution occurred and continues to take place in a vast variety of environmental conditions that range from anoxic to oxic, from hot to cold, from free-living to symbiotic, etc. Some of these physicochemical conditions are considered "extreme", particularly when inhabitants are limited to microorganisms. It is easy to imagine that microbial life in extreme environments is somehow more constrained and perhaps subjected to different evolutionary pressures. But what do we actually know about microbial evolution under extreme conditions and how can we apply that knowledge to other conditions? Appealingly, extreme environments with their relatively limited numbers of inhabitants can serve as good model systems for the study of evolutionary processes. A look at the microbial inhabitants of today's extreme environments provides a snapshot in time of evolution and adaptation to extreme conditions. These adaptations manifest at different levels from established communities and species to genome content and changes in specific genes that result in altered function or gene expression. But as a recent (2011) report from the American Academy of Microbiology observes: "A complex issue in the study of microbial evolution is unraveling the process of evolution from that of adaptation. In many cases, microbes have the capacity to adapt to various environmental changes by changing gene expression or community composition as opposed to having to evolve entirely new capabilities." We have learned much about how microbes are adapted to extreme conditions but relatively little is known about these adaptations evolved. How did the different processes of evolution such as mutation, immigration, horizontal (lateral) gene transfer, recombination, hybridization, genetic drift, fixation, positive and negative selection, and selective screens contribute to the evolution of these genes, genomes, microbial species, communities, and functions? What are typical rates of these processes? How prevalent are each of these processes under different conditions? This book explores the current state of knowledge about microbial evolution under extreme conditions and addresses the following questions: What is known about the processes of microbial evolution (mechanisms, rates, etc.) under extreme conditions? Can this knowledge be applied to other systems and what is the broader relevance? What remains unknown and requires future research? These questions will be addressed from several perspectives including different extreme environments, specific organisms, and specific evolutionary processes.

This text is devoted to a particular class of microbe & focuses on its ecology, systematics, physiological & molecular biology. Also included is a discussion of potentially exploitable biotechnological & industrial uses for extremophiles.

Many Microorganisms and some macro-organisms can live under extreme conditions. For example, high and low temperature, acidic and alkaline conditions, high salt areas, high pressure, toxic compounds, high level of ionizing radiation, anoxia and absence of light, etc. Many organisms inhabit environments characterized by more than one form of stress (Polyextremophiles). Among them are those who live in hypersaline and alkaline, hot and acidic, cold/hot and high hydrostatic pressure, etc. Polyextremophiles found in desert regions have to copy with intense UV irradiation and desiccation, high as well as low temperatures, and low availability of water and nutrients. This book provides novel results of application to polyextremophiles research ranging from nanotechnology to synthetic biology to the origin of life and beyond.

Modern methods and approaches, such as the analysis of molecular sequences to infer evolutionary relationships among organisms, have provided vast new sets of data to further our understanding ofliving organisms, but there remain enigmas in the biological world that will keep scientists working and thinking for decades. Microorganisms by virtue of their small size and almost unbounded diversity provide ample examples of intriguing mysteries that are being challenged with all of the techniques the modern scientific arsenal can provide. One whole arena of this battle to resolve puzzling mysteries about various microorganisms is the almost unbelievable ability of many micro-organisms to live in extreme environments. Whether the challenge is extreme heat, cold, pressure, hyper salinity, alkalinity or acidity, some micro-organisms live now where no life might seem possible. This fascinating state of affairs is the context for this present volume edited by Joseph Seckbach. This Volume is a compilation of many of the especially interesting questions and biological challenges that arise in the consideration of microorganisms in general and the extremophiles in particular.

This book explores microbial lifestyles, biochemical adaptations, and trophic interactions occurring in extreme environments. By summarizing the latest findings in the field it provides a valuable reference for future studies. Spark ideas for biotechnological and commercial exploitation of microbiomes at the extremes of life are presented. Chapters on viruses complement this highly informative book. In a vertical journey through the microbial biosphere it covers aspects of cold environments, hot environments, extreme saline environments, and extreme pressure environments, and more. From the deep sea, through polar deserts, up to the clouds in the air - the diversity of microbial life in all habitats is described, explored, and comprehensively reviewed. Possible biotechnical applications are discussed. This book aims to provide a useful reference for those who want to start a research program in extreme microbiology and, hopefully, inspire new research directions.

Bacteria have been the dominant forms of life on Earth for the past 3.5 billion years. They rapidly evolve, constantly changing their genetic architecture through horizontal DNA transfer and other mechanisms. Consequently, it can be difficult to define individual species and determine how they are related. Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology examines how bacteria and other microbes evolve, focusing on insights from genomics-based studies. Contributors discuss the origins of new microbial populations, the evolutionary and ecological mechanisms that keep species separate once they have diverged, and the challenges of constructing phylogenetic trees that accurately reflect their relationships. They describe the organization of microbial genomes, the various mutations that occur, including the birth of new genes de novo and by duplication, and how natural selection acts on those changes. The role of horizontal gene transfer as a strong driver of microbial evolution is emphasized throughout. The authors also explore the geologic evidence for early microbial evolution and describe the use of microbial evolution experiments to examine phenomena like natural selection. This volume will thus be essential reading for all microbial ecologists, population geneticists, and evolutionary biologists.

The book compiles the latest studies on microorganisms thriving in extreme conditions. Microbes have been found in extremely high and low temperatures, highly acidic to saline conditions, from deserts to the Dead sea, from hot-springs to underwater hydrothermal vents- the diversity is incredible. The various chapters highlight the microbial life and describe the mechanisms of tolerance to these harsh conditions, and show how an understanding of these phenomena can help us exploit the microbes in biotechnology. The theme of the book is highly significant since life in these environments can give vital clues about the origin and evolution of life on earth, as a lot of these conditions simulate the environment present billions of years ago. Additionally, the study of adaptation and survival of organisms in such environments can be important for finding life on other planets. This book shall be useful for students, researchers and course instructors interested in evolution, microbial adaptations and ecology in varied environments.