Download or read book Bacterial Genes and Genome Dynamics in the Environment written by Sonia C. Timberlake and published by . This book was released on 2013 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most marvelous features of microbial life is its ability to thrive in such diverse and dynamic environments. My scientific interest lies in the variety of modes by which microbial life accomplishes this feat. In the first half of this thesis I present tools to leverage high throughput sequencing for the study of environmental genomes. In the second half of this thesis, I describe modes of environmental adaptation by bacteria via gene content or gene expression evolution. Associating genes' usage and evolution to adaptation in various environments is a cornerstone of microbiology. New technologies and approaches have revolutionized this pursuit, and I begin by describing the computational challenges I resolved in order to bring these technologies to bear on microbial genomics. In Chapter 1, I describe SHE-RA, an algorithm that increases the useable read length of ultra-high throughput sequencing technologies, thus extending their range of applications to include environmental sequencing. In Chapter 2, I design a new hybrid assembly approach for short reads and assemble 82 Vibrio genomes. Using the ecologically defined groups of this bacterial family, I investigate the genomic and metabolic correlates of habitat and differentiation, and evaluate a neutral model of gene content. In Chapter 3, I report the extent to which orthologous genes in bacteria exhibit the same transcriptional response to the same change in environment, and describe the features and functions of bacterial transcriptional networks that are conserved. I conclude this thesis with a summary of my tools and results, their use in other studies, and their relevance to future work. In particular, I discuss the future experiments and analytical strategies that I am eager to see applied to compelling open questions in microbial ecology and evolution.
Download or read book The New Science of Metagenomics written by National Research Council and published by National Academies Press. This book was released on 2007-06-24 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although we can't usually see them, microbes are essential for every part of human life-indeed all life on Earth. The emerging field of metagenomics offers a new way of exploring the microbial world that will transform modern microbiology and lead to practical applications in medicine, agriculture, alternative energy, environmental remediation, and many others areas. Metagenomics allows researchers to look at the genomes of all of the microbes in an environment at once, providing a "meta" view of the whole microbial community and the complex interactions within it. It's a quantum leap beyond traditional research techniques that rely on studying-one at a time-the few microbes that can be grown in the laboratory. At the request of the National Science Foundation, five Institutes of the National Institutes of Health, and the Department of Energy, the National Research Council organized a committee to address the current state of metagenomics and identify obstacles current researchers are facing in order to determine how to best support the field and encourage its success. The New Science of Metagenomics recommends the establishment of a "Global Metagenomics Initiative" comprising a small number of large-scale metagenomics projects as well as many medium- and small-scale projects to advance the technology and develop the standard practices needed to advance the field. The report also addresses database needs, methodological challenges, and the importance of interdisciplinary collaboration in supporting this new field.
Download or read book The Pangenome written by Hervé Tettelin and published by Springer Nature. This book was released on 2020-04-30 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book offers the first comprehensive account of the pan-genome concept and its manifold implications. The realization that the genetic repertoire of a biological species always encompasses more than the genome of each individual is one of the earliest examples of big data in biology that opened biology to the unbounded. The study of genetic variation observed within a species challenges existing views and has profound consequences for our understanding of the fundamental mechanisms underpinning bacterial biology and evolution. The underlying rationale extends well beyond the initial prokaryotic focus to all kingdoms of life and evolves into similar concepts for metagenomes, phenomes and epigenomes. The book’s respective chapters address a range of topics, from the serendipitous emergence of the pan-genome concept and its impacts on the fields of microbiology, vaccinology and antimicrobial resistance, to the study of microbial communities, bioinformatic applications and mathematical models that tie in with complex systems and economic theory. Given its scope, the book will appeal to a broad readership interested in population dynamics, evolutionary biology and genomics.
Download or read book DNA Traffic in the Environment written by Hiromi Nishida and published by Springer. This book was released on 2019-02-21 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprehensively discusses our current understanding of the role and biological mechanisms of horizontal transfer of genetic elements in the environment, which has been important in the evolution of prokaryotes (archaea and bacteria). Horizontal transfer of genetic elements generates variations of prokaryotes and their genomes. Comparative studies of genomes revealed that it frequently occurred during archaeal and bacterial evolution. The book introduces a variety of studies related to horizontal gene transfer, gene silencing, plasmids, phages, transposons, and the emergence of microbes that degrade man-made xenobiotics and have antimicrobial resistance. Written by leading researchers in DNA traffic, the book is a valuable guide to horizontal transfer for both young scientists and experts in the field.
Download or read book Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria written by Frans J. de Bruijn and published by John Wiley & Sons. This book was released on 2016-07-13 with total page 1472 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Size Limits of Very Small Microorganisms written by National Research Council and published by National Academies Press. This book was released on 1999-10-13 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: How small can a free-living organism be? On the surface, this question is straightforward-in principle, the smallest cells can be identified and measured. But understanding what factors determine this lower limit, and addressing the host of other questions that follow on from this knowledge, require a fundamental understanding of the chemistry and ecology of cellular life. The recent report of evidence for life in a martian meteorite and the prospect of searching for biological signatures in intelligently chosen samples from Mars and elsewhere bring a new immediacy to such questions. How do we recognize the morphological or chemical remnants of life in rocks deposited 4 billion years ago on another planet? Are the empirical limits on cell size identified by observation on Earth applicable to life wherever it may occur, or is minimum size a function of the particular chemistry of an individual planetary surface? These questions formed the focus of a workshop on the size limits of very small organisms, organized by the Steering .Group for the Workshop on Size Limits of Very Small Microorganisms and held on October 22 and 23, 1998. Eighteen invited panelists, representing fields ranging from cell biology and molecular genetics to paleontology and mineralogy, joined with an almost equal number of other participants in a wide-ranging exploration of minimum cell size and the challenge of interpreting micro- and nano-scale features of sedimentary rocks found on Earth or elsewhere in the solar system. This document contains the proceedings of that workshop. It includes position papers presented by the individual panelists, arranged by panel, along with a summary, for each of the four sessions, of extensive roundtable discussions that involved the panelists as well as other workshop participants.
Download or read book Competition and Coexistence written by Ulrich Sommer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: The question "Why are there so many species?" has puzzled ecologist for a long time. Initially, an academic question, it has gained practical interest by the recent awareness of global biodiversity loss. Species diversity in local ecosystems has always been discussed in relation to the problem of competi tive exclusion and the apparent contradiction between the competitive exclu sion principle and the overwhelming richness of species found in nature. Competition as a mechanism structuring ecological communities has never been uncontroversial. Not only its importance but even its existence have been debated. On the one extreme, some ecologists have taken competi tion for granted and have used it as an explanation by default if the distribu tion of a species was more restricted than could be explained by physiology and dispersal history. For decades, competition has been a core mechanism behind popular concepts like ecological niche, succession, limiting similarity, and character displacement, among others. For some, competition has almost become synonymous with the Darwinian "struggle for existence", although simple plausibility should tell us that organisms have to struggle against much more than competitors, e.g. predators, parasites, pathogens, and envi ronmental harshness.
Download or read book Bacterial Genome and Population Dynamics with Implications for Public Health written by and published by . This book was released on 2020 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Bacterial populations are extraordinarily heterogeneous. Despite growing clonally, these populations are often composed of multiple lineages distinguished by both phenotype and genetic differences that are caused by both allelic and whole gene variation. Such genomic mosaicism and within-species variation can significantly impact a species' response to selective pressures from antibiotic use, vaccination, immune responses and host environment. One important process that contributes to this phenomenon is recombination, the exchange of very similar DNA sequences between strains which can result to either the addition or replacement of homologous genes. Current models of microbial recombination incorporate the null expectation that recombination is a homogenous process across a species, whereby different lineages of the same species and different genes within a genome exhibit the same rates of DNA donation and receipt. However, recent work has demonstrated that intra-species recombination rates can differ even between strains. This dissertation attempts to elucidate the extent of, and the processes underlying, heterogeneity in genomic content in microbial species and populations relevant to human health"--Page xii.
Download or read book Metagenomics for Microbiology written by Jacques Izard and published by Academic Press. This book was released on 2014-11-07 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concisely discussing the application of high throughput analysis to move forward our understanding of microbial principles, Metagenomics for Microbiology provides a solid base for the design and analysis of omics studies for the characterization of microbial consortia. The intended audience includes clinical and environmental microbiologists, molecular biologists, infectious disease experts, statisticians, biostatisticians, and public health scientists. This book focuses on the technological underpinnings of metagenomic approaches and their conceptual and practical applications. With the next-generation genomic sequencing revolution increasingly permitting researchers to decipher the coding information of the microbes living with us, we now have a unique capacity to compare multiple sites within individuals and at higher resolution and greater throughput than hitherto possible. The recent articulation of this paradigm points to unique possibilities for investigation of our dynamic relationship with these cellular communities, and excitingly the probing of their therapeutic potential in disease prevention or treatment of the future. Expertly describes the latest metagenomic methodologies and best-practices, from sample collection to data analysis for taxonomic, whole shotgun metagenomic, and metatranscriptomic studies Includes clear-headed pointers and quick starts to direct research efforts and increase study efficacy, eschewing ponderous prose Presented topics include sample collection and preparation, data generation and quality control, third generation sequencing, advances in computational analyses of shotgun metagenomic sequence data, taxonomic profiling of shotgun data, hypothesis testing, and mathematical and computational analysis of longitudinal data and time series. Past-examples and prospects are provided to contextualize the applications.
Download or read book Prokaryotic Genomics written by Michel Blot and published by Birkhäuser. This book was released on 2013-12-01 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prokaryotic Genomics provides molecular microbiologists in particular and researchers working with bacteria in general with the most important established recipes needed for their work. The volume covers both revisited classical methods and new tools for global analysis such as genomics or proteomics. It is written for those in need of a bench manual to complete their experiments and for those wanting to understand the modern tools used in microbiology.
Download or read book The Eco evolutionary Dynamics of Extrachromosomal Elements in Environmental Vibrio written by Hong Xue (Ph. D.) and published by . This book was released on 2014 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmids and other extrachromosomal elements (ECEs) are recognized as key factors mediating horizontal gene transfer; however, their diversity and dynamics among ecologically structured host populations in the wild remains poorly understood. Here we take a population-genomic approach to determine carriage of different types of ECEs in a recently established model for ecologically and genetically cohesive bacterial populations, asking whether different ECE types (i) are primarily associated to host phylogeny or ecology, (ii) have distinct transfer (and loss) patterns, and (iii) display different microevolutionary dynamics. We employed two models of environmental bacterial populations: a Vibrio cholerae population isolated from a coastal brackish pond (Oyster Pond, Woods Hole, MA), and diverse co-existing Vibrio populations comprising several species from Plum Island Sound (Ipswich, MA). High frequency (>40%) of a novel filamentous phage, VCYD, was detected in a collection of 531 isolates of V. cholerae. VCYD occurs both in the host-genome integrative form (IF) and a plasmid-like replicative form (RF). The relative frequency of each form differed among isolates from portions of the pond displaying different salinities, suggesting potential impact of host habitat on the biology of bacteriophages. Using the second model, we isolated 187 ECEs from 660 isolates previously categorized into 25 different ecologically and genetically cohesive populations. We identified the following elements: 22 bacteriophages, and 24 conjugative, 38 mobilizable and 103 so-called non-transmissible ECEs. While mobilizable ECEs require co-occurring conjugative plasmids for successful transfer, non-transmissible ECEs do not encode any genes for self-transfer. We further found that ECEs were significantly enriched in free-living cells, suggesting association of ECEs with host environment. The finding of phage as a major and stable ECE component is surprising and the absence of any integrase genes suggests that these are lysogens that do not integrate into the host genome. Finally, our data show that a type of plasmids previously defined as "non-transmissible" appears to be most common among Vibrio ECEs and that they have been transferred recently and frequently among distantly related populations through mechanisms yet to be uncovered. Overall, this study suggests a dynamic mobile gene pool with high turnover among host populations.
Download or read book Gene Transfer in the Environment written by Stuart B. Levy and published by McGraw-Hill Companies. This book was released on 1989 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Social Biology of Microbial Communities written by Institute of Medicine and published by National Academies Press. This book was released on 2013-01-10 with total page 633 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beginning with the germ theory of disease in the 19th century and extending through most of the 20th century, microbes were believed to live their lives as solitary, unicellular, disease-causing organisms . This perception stemmed from the focus of most investigators on organisms that could be grown in the laboratory as cellular monocultures, often dispersed in liquid, and under ambient conditions of temperature, lighting, and humidity. Most such inquiries were designed to identify microbial pathogens by satisfying Koch's postulates.3 This pathogen-centric approach to the study of microorganisms produced a metaphorical "war" against these microbial invaders waged with antibiotic therapies, while simultaneously obscuring the dynamic relationships that exist among and between host organisms and their associated microorganisms-only a tiny fraction of which act as pathogens. Despite their obvious importance, very little is actually known about the processes and factors that influence the assembly, function, and stability of microbial communities. Gaining this knowledge will require a seismic shift away from the study of individual microbes in isolation to inquiries into the nature of diverse and often complex microbial communities, the forces that shape them, and their relationships with other communities and organisms, including their multicellular hosts. On March 6 and 7, 2012, the Institute of Medicine's (IOM's) Forum on Microbial Threats hosted a public workshop to explore the emerging science of the "social biology" of microbial communities. Workshop presentations and discussions embraced a wide spectrum of topics, experimental systems, and theoretical perspectives representative of the current, multifaceted exploration of the microbial frontier. Participants discussed ecological, evolutionary, and genetic factors contributing to the assembly, function, and stability of microbial communities; how microbial communities adapt and respond to environmental stimuli; theoretical and experimental approaches to advance this nascent field; and potential applications of knowledge gained from the study of microbial communities for the improvement of human, animal, plant, and ecosystem health and toward a deeper understanding of microbial diversity and evolution. The Social Biology of Microbial Communities: Workshop Summary further explains the happenings of the workshop.
Download or read book Ecological Genomics written by Christian R. Landry and published by Springer Science & Business Media. This book was released on 2013-11-25 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researchers in the field of ecological genomics aim to determine how a genome or a population of genomes interacts with its environment across ecological and evolutionary timescales. Ecological genomics is trans-disciplinary by nature. Ecologists have turned to genomics to be able to elucidate the mechanistic bases of the biodiversity their research tries to understand. Genomicists have turned to ecology in order to better explain the functional cellular and molecular variation they observed in their model organisms. We provide an advanced-level book that covers this recent research and proposes future development for this field. A synthesis of the field of ecological genomics emerges from this volume. Ecological Genomics covers a wide array of organisms (microbes, plants and animals) in order to be able to identify central concepts that motivate and derive from recent investigations in different branches of the tree of life. Ecological Genomics covers 3 fields of research that have most benefited from the recent technological and conceptual developments in the field of ecological genomics: the study of life-history evolution and its impact of genome architectures; the study of the genomic bases of phenotypic plasticity and the study of the genomic bases of adaptation and speciation.
Download or read book Structure and Function of the Bacterial Genome written by Charles J. Dorman and published by John Wiley & Sons. This book was released on 2020-04-28 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents an integrated view of the expression of bacterial genetic information, genome architecture and function, and bacterial physiology and pathogenesis This book blends information from the very latest research on bacterial chromosome and nucleoid architecture, whole-genome analysis, cell signaling, and gene expression control with well-known gene regulation paradigms from model organisms (including pathogens) to give readers a picture of how information flows from the environment to the gene, modulating its expression and influencing the competitive fitness of the microbe. Structure and Function of the Bacterial Genome explores the governance of the expression of the genes that make a bacterium what it is, and updates the basics of gene expression control with information about transcription promoter structure and function, the role of DNA as a regulatory factor (in addition to its role as a carrier of genetic information), small RNAs, RNAs that sense chemical signals, ribosomes and translation, posttranslational modification of proteins, and protein secretion. It looks at the forces driving the conservation and the evolution of the dynamic genome and offers chapters that cover DNA replication, DNA repair, plasmid biology, recombination, transposition, the roles of repetitive DNA sequences, horizontal gene transfer, the defense of the genome by CRISPR-Cas, restriction enzymes, Argonaute proteins and BREX systems. The book finishes with a chapter that gives an integrated overview of genome structure and function. Blends knowledge of gene regulatory mechanisms with a consideration of nucleoid structure and dynamics Offers a 'DNA-centric' approach to considering transcription control Views horizontal gene transfer from a gene regulation perspective Assesses the opportunities and limitations of designing synthetic microbes or rewiring existing ones Structure and Function of the Bacterial Genome is an ideal book for graduate and undergraduate students studying microbial cell biology, bacterial pathogenesis, gene regulation, and molecular microbiology. It will also appeal to principal investigators conducting research on these and related topics and researchers in synthetic biology and other arms of biotechnology.
Download or read book Combating Antimicrobial Resistance written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2018-01-08 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: As of 2017, the emergence and spread of antimicrobial resistance continues unabated around the world, leaving devastating health and economic outcomes in its wake. Those consequences will multiply if collaborative global action is not taken to address the spread of resistance. Major drivers of antimicrobial resistance in humans have been accelerated by inappropriate antimicrobial prescribing in health care practices; the inappropriate use of antimicrobials in livestock; and the promulgation of antibiotic resistance genes in the environment. To explore the issue of antimicrobial resistance, the Forum of Microbial Threats planned a public workshop. Participants explored issues of antimicrobial resistance through the lens of One Health, which is a collaborative approach of multiple disciplines - working locally, nationally, and globally - for strengthening systems to counter infectious diseases and related issues that threaten human, animal, and environmental health, with an end point of improving global health and achieving gains in development. They also discussed immediate and short-term actions and research needs that will have the greatest effect on reducing antimicrobial resistance, while taking into account the complexities of bridging different sectors and disciplines to address this global threat. This publication summarizes the presentations and discussions from the workshop.
Download or read book Microbial Evolution written by Howard Ochman and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
