Catálogo de publicaciones - revistas

<jats:p>The growing number of complete microbial genome sequences provides a powerful tool for studying the biology of microorganisms. In combination with assays for function, genomic-based approaches can facilitate efficient and directed research strategies to elucidate mechanisms of bacterial pathogenicity. As genomic information accrues, the challenge remains to construct a picture of the biology that accurately reflects how individual genes collaborate to create the complex world of microbial specialization.</jats:p>

<jats:p> A major breakthrough in understanding the bacterial cell is the discovery that the cell is highly organized at the level of protein localization. Proteins are positioned at particular sites in bacteria, including the cell pole, the incipient division plane, and the septum. Differential protein localization can control DNA replication, chromosome segregation, and cytokinesis and is responsible for generating daughter cells with different fates upon cell division. Recent discoveries have revealed that progression through the cell cycle and communication between cellular compartments are mediated by two-component signal transduction systems and signaling pathways involving transcription factor activation by proteolytic processing. Asymmetric cell division in <jats:italic>Caulobacter crescentus</jats:italic> and sporulation in <jats:italic>Bacillus subtilis</jats:italic> are used as paradigms for the control of the cell cycle and cellular morphogenesis in bacterial cells. </jats:p>

<jats:p>Interest in bacterial pathogenesis has recently increased because of antibiotic resistance, the emergence of new pathogens and the resurgence of old ones, and the lack of effective therapeutics. The molecular and cellular mechanisms of microbial pathogenesis are currently being defined, with precise knowledge of both the common strategies used by multiple pathogenic bacteria and the unique tactics evolved by individual species to help establish infection. What is emerging is a new appreciation of how bacterial pathogens interact with host cells. Many host cell functions, including signal transduction pathways, cytoskeletal rearrangements, and vacuolar trafficking, are exploited, and these are the focus of this review. A bonus of this work is that bacterial virulence factors are providing new tools to study various aspects of mammalian cell functions, in addition to mechanisms of bacterial disease. Together these developments may lead to new therapeutic strategies.</jats:p>

<jats:p>Analysis of viral and bacterial pathogenesis has revealed common themes in the ways in which plants and animals respond to pathogenic agents. Pathogenic bacteria use macromolecule delivery systems (types III and IV) to deliver microbial avirulence proteins and transfer DNA-protein complexes directly into plant cells. The molecular events that constitute critical steps of plant-pathogen interactions seem to involve ligand-receptor mechanisms for pathogen recognition and the induction of signal transduction pathways in the plant that lead to defense responses. Unraveling the molecular basis of disease resistance pathways has laid a foundation for the rational design of crop protection strategies.</jats:p>

<jats:p>Over three decades of molecular-phylogenetic studies, researchers have compiled an increasingly robust map of evolutionary diversification showing that the main diversity of life is microbial, distributed among three primary relatedness groups or domains: Archaea, Bacteria, and Eucarya. The general properties of representatives of the three domains indicate that the earliest life was based on inorganic nutrition and that photosynthesis and use of organic compounds for carbon and energy metabolism came comparatively later. The application of molecular-phylogenetic methods to study natural microbial ecosystems without the traditional requirement for cultivation has resulted in the discovery of many unexpected evolutionary lineages; members of some of these lineages are only distantly related to known organisms but are sufficiently abundant that they are likely to have impact on the chemistry of the biosphere.</jats:p>