Download or read book Studies of Archaeal Virus host Systems in Thermal Environments written by and published by . This book was released on 2013 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Isolation and Studies of Virus host Systems from Non Acidic Geothermal Environments written by Tomohiro Mochizuki and published by . This book was released on 2012 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Viruses are known to infect members of all three domains, Eukarya, Bacteria and Archaea, but our knowledge about viruses infecting Archaea is still in its infancy. We have chosen an aerobic archaeon Aeropyrum pernix, growing optimally at pH7.0, 90-95°C, as a target host to broaden our knowledge of hyperthermophilic archaeal viruses. No virus of the genus Aeropyrum, nor the order Desulfurococcales, had been described prior to the PhD project. In the course of the research, four novel viruses of A. pernix have been isolated and studied. Firstly, the presence of two putative proviruses in the genome of A. pernix K1 was predicted by in silico analysis, and the two viruses Aeropyrum pernix spindle-shaped virus 1 (APSV1), and Aeropyrum pernix ovoid virus 1 (APOV1) were induced and isolated, and their genomes and morphotypes were characterized. The next approach was based on the screening for viruses infecting A. pernix in the environmental samples collected at hydrothermal areas close to the origin of A. pernix. This resulted in the discovery, isolation and characterization of Aeropyrum pernix bacilliform virus 1 (APBV1), and Aeropyrum spring-shaped virus (ASPV). The virus ASPV is the first hyperthermophilic archaeal virus with a ssDNA genome. The genome sequences of all four isolated viruses show no significant similarity with genomes of other known viruses. This result, along with unique morphological properties of the viruses APBV1 and ASPV, served as a basis for the proposal of two novel virus families, the Clavaviridae (APBV1) and Spiraviridae (ASPV). Together, the results of the research contributed to a better understanding of the viral diversity on our planet.
Download or read book Structural and Functional Studies of Archaeal Viruses written by C. Martin Lawrence and published by . This book was released on 2009 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Viruses populate virtually every ecosystem on the planet, including the extreme acidic, thermal, and saline environments where archaeal organisms can dominate. For example, recent studies have identified crenarchaeal viruses in the hot springs of Yellowstone National Park and other high temperature environments worldwide. These viruses are often morphologically and genetically unique, with genomes that show little similarity to genes of known function, complicating efforts to understand their viral life cycles. Here, we review progress in understanding these fascinating viruses at the molecular level and the evolutionary insights coming from these studies.
Download or read book Viruses of Hyperthermophilic Archaea written by Emmanuelle Quemin and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although, archaea were initially regarded as exotic microorganisms capable of growing in conditions which are hostile to humans, it became clear that they are ubiquitous and abundant in various environments. Detailed studies focusing on different aspects of archaeal biology have led to many unexpected discoveries, including the unique virosphere associated with archaea. Indeed, highly diverse viruses characterized by uncommon virion shapes and mysterious genomic contents have been isolated that typically do not resemble viruses of either bacteria or eukaryotes. Recent analysis of the sequential events of the viral cycle resulted in major breakthroughs in the field. In the framework of my PhD studies, I have focused on two model hyperthermo-acidophilic virus-host systems, the spindle-shaped SSV1 and rod-shaped SIRV2, both infecting organisms of the genus Sulfolobus. Initially, we defined structure-based lineages for all known spindle-shaped viruses isolated from highly divergent hosts and residing in very different environments. Then, we provided insights into the architecture of spindle-shaped viruses by showing that SSV1 virions are composed of glycosylated structural proteins and contain a lipid envelope. Finally, we focused on virus-host interplay. Whereas SIRV2 virions appear to use a similar entry strategy as flagellotrophic bacteriophages, SSV1 virions employ an exit mechanism reminiscent of the budding of eukaryotic enveloped viruses. Collectively, these studies shed light on the biology of archaeal viruses and help to define interesting targets that should be the focus of intensive research in the next future.
Download or read book Archaeal Host Virus Interactions written by Jennifer Fulton Wirth and published by . This book was released on 2011 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Viruses are the most abundant biological entity on earth, and virus-host interactions are one of the most important factors shaping microbial populations (Suttle, 2007b). The study of both the cellular and viral members of the domain Archaea is a relatively new field. Thus, the viruses (and their cellular hosts) of Archaea are poorly understood as compared to viruses of Bacteria and Eukarya. This work has sought to expand our understanding of archaeal viruses by two general approaches. The first is by developing and implementing the use of a genetic system for a crenarchaeal virus, Sulfolobus turreted icosahedral virus (STIV), isolated from a hot (82°C) acidic (pH 2.2) pool in Yellowstone National Park, USA. The second approach has been to look at viral communities and their interactions with their cellular hosts in natural environments. We have developed a genetic tool, an infectious clone for STIV, which has allowed for genetic analysis of this virus. A number of viral genes have been knocked out, and their functions investigated using this tool. We have determined that at least three viral genes, A197, B345 and C381, are required for viral replication, while one gene, B116, is not essential. Work continues investigating function for other STIV genes as well as specific interactions with its host, Sulfolobus solfataricus. We have performed total community sequencing (metagenomics) for both the cellular and viral populations of several hot springs in Yellowstone National Park. We have been able to assemble a near full-length putative novel viral genome from one of these sites. We have also performed an in depth analysis of the function of a newly described bacterial and archaeal adaptive immune system (CRISPR/Cas) in a natural environment. This study has provided insights into the function of this immune system in a complex nutrient limited environment, which would not have been observed by studying cultured isolates in a laboratory.
Download or read book The Prevalence of STIV C92 Like Proteins in Acidic Thermal Environments written by Jamie C. Snyder and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new type of viral-induced lysis system has recently been discovered for two unrelated archaeal viruses, STIV and SIRV2. Prior to the lysis of the infected host cell, unique pyramid-like lysis structures are formed on the cell surface by the protrusion of the underlying cell membrane through the overlying external S-layer. It is through these pyramid structures that assembled virions are released during lysis. The STIV viral protein c92 is responsible for the formation of these lysis structures. We searched for c92-like proteins in viral sequences present in multiple viral and cellular metagenomic libraries from Yellowstone National Park acidic hot spring environments. Phylogenetic analysis of these proteins demonstrates that, although c92-like proteins are detected in these environments, some are quite divergent and may represent new viral families. We hypothesize that this new viral lysis system is common within diverse archaeal viral populations found within acidic hot springs.
Download or read book Isolation and Characterization of Hyperthermophilic Archaeal Viruses written by Diana Paola Baquero Uriza and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extreme geothermal environments are inhabited by archaeal viruses with unique genome contents and remarkable morphologies, many of which have not been described among viruses infecting bacteria or eukaryotes. However, the number of known species of viruses infecting archaea remains low compared to the eukaryotic or bacterial viruses. Moreover, the lack of relationships to other known viruses and distinctiveness of their genomes suggest that the mechanisms of virus-host interaction are likely to be also novel. Therefore, in the framework of my studies, I have focused on two major lines of research: (i) isolation and characterization of new hyperthermophilic archaeal viruses and (ii) molecular mechanisms of virus-host interactions in Archaea. We investigated the virus diversity in the sulfurous fields of the Campi Flegrei volcano in Pozzuoli, Italy. Five new archaeal viruses infecting neutrophilic hyperthermophiles of the genus Pyrobaculum and acidophilic hyperthermophiles belonging to three different genera of the order Sulfolobales, namely, Saccharolobus, Acidianus, and Metallosphaera were isolated. The newly characterized viruses belong to the families Rudiviridae, Globuloviridae and Tristromaviridae. Notably, phylogenomic analysis of the newly isolated and previously sequenced rudiviruses revealed a clear biogeographic pattern, with all Italian rudiviruses forming a monophyletic clade, suggesting geographical structuring of virus communities in extreme geothermal environments. One of the non-enveloped rudiviruses isolated in Pozzuoli, namely, Saccharolobus solfataricus rod-shaped virus 1 (SSRV1), and the enveloped Sulfolobus islandicus filamentous virus (SIFV) were structurally and biochemically characterized. The study has revealed conserved structural features shared by these viruses and clarified the evolutionary relationship between non-enveloped and enveloped filamentous viruses. The second line of research focused on understanding the mechanisms of virion assembly and release on the example of the enveloped filamentous virus SIFV, which infects the hyperthermophilic and acidophilic archaeon Sulfolobus islandicus. Our results showed that SIFV is a lytic virus, which is released through pyramidal portals formed in the host cell membrane, a highly unexpected egress mechanism for an enveloped virus. Interestingly, dual-axis electron tomography revealed that SIFV virions acquire their lipid envelopes inside the host through an unknown mechanism, involving either de novo membrane formation or trafficking of lipids from the cytoplasmic membrane to virion assembly centers.
Download or read book Archaeal Virus host Interactions written by Tessa Quax and published by . This book was released on 2013 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this thesis provides novel insights in several aspects of the molecular biology of Archaea, Bacteria and their viruses. The archaeal virus Sulfolobus islandicus rod-shaped virus 2 (SIRV2), has a remarkable infection cycle. Infection with SIRV2 results in the formation of large virus associated pyramids (VAPs) on the host cell surface. The pyramids open during the final step of the infection cycle, to allow the release of virions. This virus release mechanism is unique. The VAPs are formed by self-assembly of one virus-encoded protein, PVAP. VAPs exist as discrete particles, and are baseless pyramids with heptagonal perimeter. The assembly process of the VAPs is described, based on cryo-electron tomography experiments and mutational analysis of PVAP. VAPs consists of two layers of which the outer one continuous with the cell membrane. PVAP expression in bacterial and eukaryotic cells resulted in VAP formation on nearly all membranes, demonstrating that PVAP serves as a universal membrane remodeling system, which might be exploited for biotechnological purposes. Whole transcriptome sequencing allowed determination of a global map of virus and host gene expression during the infection cycle. Host genes involved in anti-viral defence are activated (i.e. CRISPR-Cas and toxin anti-toxin systems). The multi-subunit protein complexes crucial for CRISPR anti-viral defence have an uneven stoichiometry and are encoded on operons. It is shown that differential translation is a key determinant of modulated expression of genes clustered in operons and that codon bias generally is the best in silico indicator of unequal protein production.
Download or read book Archaea written by Roger A. Garrett and published by John Wiley & Sons. This book was released on 2008-05-12 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduced by Crafoord Prize winner Carl Woese, this volumecombines reviews of the major developments in archaeal researchover the past 10–15 years with more specialized articlesdealing with important recent breakthroughs. Drawing on majorthemes presented at the June 2005 meeting held in Munich to honorthe archaea pioneers Wolfram Zillig and Karl O. Stetter, the bookprovides a thorough survey of the field from its controversialbeginnings to its ongoing expansion to include aspects ofeukaryotic biology. The editors have assembled articles from the premier researchersin this rapidly burgeoning field, including an account by CarlWoese of his original discovery of the Archaea (until 1990 termedarchaebacteria) and the initially mixed reactions of the scientificcommunity. The review chapters and specialized articles address theemerging significance of the Archaea within a broader scientificand technological context, and include accounts of cutting-edgeresearch developments. The book spans archaeal evolution,physiology, and molecular and cellular biology and will be anessential reference for both graduate students and researchers.
Download or read book Encyclopedia of Virology written by and published by Academic Press. This book was released on 2021-02-24 with total page 4109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encyclopedia of Virology, Fourth Edition, Five Volume Set builds on the solid foundation laid by the previous editions, expanding its reach with new and timely topics. In five volumes, the work provides comprehensive coverage of the whole virosphere, making this a unique resource. Content explores viruses present in the environment and the pathogenic viruses of humans, animals, plants and microorganisms. Key areas and concepts concerning virus classification, structure, epidemiology, pathogenesis, diagnosis, treatment and prevention are discussed, guiding the reader through chapters that are presented at an accessible level, and include further readings for those needing more specific information. More than ever now, with the Covid19 pandemic, we are seeing the huge impact viruses have on our life and society. This encyclopedia is a must-have resource for scientists and practitioners, and a great source of information for the wider public. Offers students and researchers a one-stop shop for information on virology not easily available elsewhere Fills a critical gap of information in a field that has seen significant progress in recent years Authored and edited by recognized experts in the field, with a range of different expertise, thus ensuring a high-quality standard
Download or read book Viruses Essential Agents of Life written by Günther Witzany and published by Springer Science & Business Media. This book was released on 2012-11-13 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: A renaissance of virus research is taking centre stage in biology. Empirical data from the last decade indicate the important roles of viruses, both in the evolution of all life and as symbionts of host organisms. There is increasing evidence that all cellular life is colonized by exogenous and/or endogenous viruses in a non-lytic but persistent lifestyle. Viruses and viral parts form the most numerous genetic matter on this planet.
Download or read book Principles of Molecular Virology written by Alan Cann and published by Elsevier. This book was released on 2005-07-26 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Principles of Molecular Virology, Fourth Edition" provides an essential introduction to modern virology in a clear and concise manner. It is a highly enjoyable and readable text with numerous illustrations that enhance the reader's understanding of important principles. It contains new material on virus structure, virus evolution, zoonoses, bushmeat, SARS and bioterrorism. The standard version includes a CD-ROM with Flash animations, virtual interactive tutorials and experiments, self-assessment questions, useful online resources, along with the glossary, classification of subcellular infectious agents and history of virology.
Download or read book Thermophiles written by Frank Robb and published by CRC Press. This book was released on 2007-12-13 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: We might think of them as living on the very edge of existence. Referred to as extremophiles, these microorganisms exhibit the most radical capacity for adaptation in those harsh environments that are just barely conducive to the existence of cellular life. Unlocking the mechanisms and understanding the evolutionary development that allows these si
Download or read book Life in Extreme Environments written by Ricardo Amils Pibernat and published by Springer Science & Business Media. This book was released on 2007-07-21 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an intriguing look at how life can adapt to many different extreme environments. It addresses the limits for life development and examines different strategies used by organisms to adapt to different extreme environments.
Download or read book Origin and Evolution of Viruses written by Esteban Domingo and published by Elsevier. This book was released on 2008-06-23 with total page 573 pages. Available in PDF, EPUB and Kindle. Book excerpt: New viral diseases are emerging continuously. Viruses adapt to new environments at astounding rates. Genetic variability of viruses jeopardizes vaccine efficacy. For many viruses mutants resistant to antiviral agents or host immune responses arise readily, for example, with HIV and influenza. These variations are all of utmost importance for human and animal health as they have prevented us from controlling these epidemic pathogens. This book focuses on the mechanisms that viruses use to evolve, survive and cause disease in their hosts. Covering human, animal, plant and bacterial viruses, it provides both the basic foundations for the evolutionary dynamics of viruses and specific examples of emerging diseases. NEW - methods to establish relationships among viruses and the mechanisms that affect virus evolution UNIQUE - combines theoretical concepts in evolution with detailed analyses of the evolution of important virus groups SPECIFIC - Bacterial, plant, animal and human viruses are compared regarding their interation with their hosts
Download or read book Human Herpesviruses written by Ann Arvin and published by Cambridge University Press. This book was released on 2007-08-16 with total page 1325 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive account of the human herpesviruses provides an encyclopedic overview of their basic virology and clinical manifestations. This group of viruses includes human simplex type 1 and 2, Epstein–Barr virus, Kaposi's Sarcoma-associated herpesvirus, cytomegalovirus, HHV6A, 6B and 7, and varicella-zoster virus. The viral diseases and cancers they cause are significant and often recurrent. Their prevalence in the developed world accounts for a major burden of disease, and as a result there is a great deal of research into the pathophysiology of infection and immunobiology. Another important area covered within this volume concerns antiviral therapy and the development of vaccines. All these aspects are covered in depth, both scientifically and in terms of clinical guidelines for patient care. The text is illustrated generously throughout and is fully referenced to the latest research and developments.
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.
