Trends in microbiology

The clinical importance of understanding the evolution of papillomaviruses.

Publication Date: 2010 Aug 23 PMID: 20739182
Authors: Bravo, I. G. - de Sanjose, S. - Gottschling, M.
Journal: Trends Microbiol

A significant fraction of human cancers is associated with infections by different papillomaviruses (PVs). In other vertebrates, the presence of specific PVs is also associated with different neoplasias. The popular view of PVs conceives them to be largely static and relies on generalized assumptions that have rarely been rigorously tested such as: virus-host codivergence, strict tissue tropism and host-specificity, their very low mutation rate and the absence of recombination. Here, we want to stress the need and the medical importance of understanding the evolutionary history and present-day dynamics of PVs. Understanding the way that PV genomes have evolved will clarify the link between a given genotype and the phenotypic and clinical outcome of the corresponding viral infection.

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Models and approaches to dissect host-symbiont specificity.

Publication Date: 2010 Aug 20 PMID: 20729086
Authors: Mandel, M. J.
Journal: Trends Microbiol

Animals are symbiotic superorganisms, composed of eukaryotic cells and specific microbial residents that perform essential functions for their host. As humans, we are beginning to appreciate the diversity and function of our own microbiota, but model systems are leading the field in illustrating the molecular mechanisms that allow specific relationships to be recapitulated during each host generation. This review focuses on models in which genetic screens, coupled with genomics, imaging, phylogenetics and population biology, have begun to allow a remarkably detailed investigation into the molecular dissection of the evolution of host specificity in animal symbionts.

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Epigenetic reprogramming of host genes in viral and microbial pathogenesis.

Publication Date: 2010 Aug 17 PMID: 20724161
Authors: Paschos, K. - Allday, M. J.
Journal: Trends Microbiol

One of the key questions in the study of mammalian gene regulation is how epigenetic methylation patterns on histones and DNA are initiated and established. These stable, heritable, covalent modifications are largely associated with the repression or silencing of gene transcription, and when deregulated can be involved in the development of human diseases such as cancer. This article reviews examples of viruses and bacteria known or thought to induce epigenetic changes in host cells, and how this might contribute to disease. The heritable nature of these processes in gene regulation suggests that they could play important roles in chronic diseases associated with microbial persistence; they might also explain so-called 'hit-and-run' phenomena in infectious disease pathogenesis.

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BST-2/tetherin: a new component of the innate immune response to enveloped viruses.

Publication Date: 2010 Sep PMID: 20688520
Authors: Evans, D. T. - Serra-Moreno, R. - Singh, R. K. - Guatelli, J. C.
Journal: Trends Microbiol

The interferon-inducible, transmembrane protein BST-2 (CD317, tetherin) directly holds fully formed enveloped virus particles to the cells that produce them, inhibiting their spread. BST-2 inhibits members of the retrovirus, filovirus, arenavirus and herpesvirus families. These viruses encode a variety of proteins to degrade BST-2 and/or direct it away from its site of action at the cell surface. Viral antagonism has subjected BST-2 to positive selection, leading to species-specific differences that presented a barrier to the transmission of simian immunodeficiency viruses (SIVs) to humans. This barrier was crossed by HIV-1 when its Vpu protein acquired activity as a BST-2 antagonist. Here, we review this new host-pathogen relationship and discuss its impact on the evolution of primate lentiviruses and the origins of the HIV pandemic.

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Nanostructured bacterial materials for innovative medicines.

Publication Date: 2010 Sep PMID: 20674365
Authors: Rodriguez-Carmona, E. - Villaverde, A.
Journal: Trends Microbiol

The development of innovative medicines and personalized biomedical approaches require the identification and implementation of new biocompatible materials produced by methodologically simple and cheap fabrication methods. The biological fabrication of materials, mostly carried out by microorganisms, has historically provided organic compounds with wide-spectrum biomedical applications, including hyaluronic acid, poly(gamma-glutamic acid) and polyhydroxyalkanoates. Additionally, the implementation of new methodological platforms such as metabolic engineering and systems biology have facilitated the controlled production of natural nanoparticles produced by bacteria, including metallic deposits of Au, Ag, Cd, Zn or Fe, virus-like particles or other nanoscale protein-only entities. The unexpected potential of such self-organized and functional materials in nanomedical scenarios (especially in drug delivery, imaging and tissue engineering) prompts serious consideration of further exploitation of bacterial cell factories as convenient alternatives to chemical synthesis and as sources of novel bioproducts that could dramatically expand the existing catalog of biomedical materials.

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Deep-sea piezosphere and piezophiles: geomicrobiology and biogeochemistry.

Publication Date: 2010 Sep PMID: 20663673
Authors: Fang, J. - Zhang, L. - Bazylinski, D. A.
Journal: Trends Microbiol

The deep-sea piezosphere accounts for approximately 75% of the total ocean volume and hosts active and diverse biological communities. Evidence obtained thus far suggests that the microbial biomass present in the piezosphere is significant. Continued international interest in exploring the deep ocean provides impetus to increase our understanding of the deep-sea piezosphere and of the influence of piezophilic microbial communities on the global ocean environment and on biogeochemical cycling occurring in the deep sea. Here, we review the diversity, metabolic characteristics, geomicrobiology and biogeochemistry of the deep-sea piezophiles.

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Unlocking pathogen genotyping information for public health by mathematical modeling.

Publication Date: 2010 Sep PMID: 20638846
Authors: Kretzschmar, M. - Gabriela M Gomes, M. - Coutinho, R. A. - Koopman, J. S.
Journal: Trends Microbiol

Molecular typing and mathematical modeling have gone through rapid development in the past decade. Both offer new insights into the epidemiology of infectious diseases, thereby contributing to a better understanding of transmission dynamics. Infectious disease surveillance and control benefit from the optimum use of these techniques. In this paper, we review recent developments and propose methods to integrate pathogen ecology and molecular evolution based on their common dependence on the underlying host contact patterns.

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Microbial nanoscopy: a closer look at microbial cell surfaces.

Publication Date: 2010 Sep PMID: 20630762
Authors: Dupres, V. - Alsteens, D. - Andre, G. - Dufrene, Y. F.
Journal: Trends Microbiol

How cell envelope constituents are spatially organised and how they interact with the environment are key questions in microbiology. Unlike other bioimaging tools, atomic force microscopy (AFM) provides information about the nanoscale surface architecture of living cells and about the localization and interactions of their individual constituents. These past years have witnessed remarkable advances in our use of the AFM molecular toolbox to observe and force probe microbial cells. Recent milestones include the real-time imaging of the nanoscale organization of cell walls, the quantification of subcellular chemical heterogeneities, the mapping and functional analysis of individual cell wall constituents and the analysis of the mechanical properties of single receptors and sensors.

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What's in a name? The semantics of quorum sensing.

Publication Date: 2010 Sep PMID: 20573513
Authors: Platt, T. G. - Fuqua, C.
Journal: Trends Microbiol

The expression of many bacterial phenotypes is regulated according to the concentration of chemical cues that they or other bacteria produce, a process often termed quorum sensing (QS). Many aspects of the environment can affect cue concentration. Thus these molecules might be indirect proxies for any one or combination of environmental factors. Recent research suggests that the adaptive significance of QS varies depending on its evolutionary and ecological context. Consequently, some researchers have proposed new terms, each emphasizing different adaptive functions, for the QS process. However, these new terms generate potential for a semantic quagmire and perpetuate the questionable notion that we can identify a single, dominant environmental feature to which the microbes respond. In fact, the ecological context of QS regulation, like the process itself, is complex and impacted by multiple aspects of natural environments.

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