| 1. |
- Andersson, Dan I., et al.
(författare)
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Antibiotic resistance and its cost : is it possible to reverse resistance?
- 2010
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 8:4, s. 260-271
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Forskningsöversikt (refereegranskat)abstract
- Most antibiotic resistance mechanisms are associated with a fitness cost that is typically observed as a reduced bacterial growth rate. The magnitude of this cost is the main biological parameter that influences the rate of development of resistance, the stability of the resistance and the rate at which the resistance might decrease if antibiotic use were reduced. These findings suggest that the fitness costs of resistance will allow susceptible bacteria to outcompete resistant bacteria if the selective pressure from antibiotics is reduced. Unfortunately, the available data suggest that the rate of reversibility will be slow at the community level. Here, we review the factors that influence the fitness costs of antibiotic resistance, the ways by which bacteria can reduce these costs and the possibility of exploiting them.
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| 2. |
- Andersson, Dan I., et al.
(författare)
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Microbiological effects of sublethal levels of antibiotics
- 2014
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 12:7, s. 465-478
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Forskningsöversikt (refereegranskat)abstract
- The widespread use of antibiotics results in the generation of antibiotic concentration gradients in humans, livestock and the environment. Thus, bacteria are frequently exposed to non-lethal (that is, subinhibitory) concentrations of drugs, and recent evidence suggests that this is likely to have an important role in the evolution of antibiotic resistance. In this Review, we discuss the ecology of antibiotics and the ability of subinhibitory concentrations to select for bacterial resistance. We also consider the effects of low-level drug exposure on bacterial physiology, including the generation of genetic and phenotypic variability, as well as the ability of antibiotics to function as signalling molecules. Together, these effects accelerate the emergence and spread of antibiotic-resistant bacteria among humans and animals.
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| 3. |
- Ankarklev, Johan, et al.
(författare)
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Behind the smile : cell biology and disease mechanisms of Giardia species
- 2010
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 8:6, s. 413-422
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Forskningsöversikt (refereegranskat)abstract
- The eukaryotic intestinal parasite Giardia intestinalis was first described in 1681, when Antonie van Leeuwenhoek undertook a microscopic examination of his own diarrhoeal stool. Nowadays, although G. intestinalis is recognized as a major worldwide contributor to diarrhoeal disease in humans and other mammals, the disease mechanisms are still poorly understood. Owing to its reduced complexity and proposed early evolutionary divergence, G. intestinalis is used as a model eukaryotic system for studying many basic cellular processes. In this Review we discuss recent discoveries in the molecular cell biology and pathogenesis of G. intestinalis.
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| 4. |
- Gribaldo, Simonetta, et al.
(författare)
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The origin of eukaryotes and their relationship with the Archaea : are we at a phylogenomic impasse?
- 2010
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Ingår i: Nature Reviews Microbiology. - 1740-1526 .- 1740-1534. ; 8:10, s. 743-752
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Tidskriftsartikel (refereegranskat)abstract
- The origin of eukaryotes and their evolutionary relationship with the Archaea is a major biological question and the subject of intense debate. In the context of the classical view of the universal tree of life, the Archaea and the Eukarya have a common ancestor, the nature of which remains undetermined. Alternative views propose instead that the Eukarya evolved directly from a bona fide archaeal lineage. Several recent large-scale phylogenomic studies using an array of approaches are divided in supporting either one or the other scenario, despite analysing largely overlapping data sets of universal genes. We examine the reasons for such a lack of consensus and consider how alternative approaches may enable progress in answering this fascinating and as-yet-unresolved question.
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| 5. |
- Gripenland, Jonas, et al.
(författare)
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RNAs : regulators of bacterial virulence
- 2010
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 8:12, s. 857-866
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Tidskriftsartikel (refereegranskat)abstract
- RNA-based pathways that regulate protein expression are much more widespread than previously thought. Regulatory RNAs, including 5' and 3' untranslated regions next to the coding sequence, cis-acting antisense RNAs and trans-acting small non-coding RNAs, are effective regulatory molecules that can influence protein expression and function in response to external cues such as temperature, pH and levels of metabolites. This Review discusses the mechanisms by which these regulatory RNAs, together with accessory proteins such as RNases, control the fate of mRNAs and proteins and how this regulation influences virulence in pathogenic bacteria.
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| 6. |
- Johansson, Cecilia, et al.
(författare)
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Regulation of human papillomavirus gene expression by splicing and polyadenylation.
- 2013
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 11:4, s. 239-51
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Tidskriftsartikel (refereegranskat)abstract
- Human papillomaviruses (HPVs) are small DNA tumour viruses that are present in more than 99% of all cervical cancers. The ability of these viruses to cause disease is partly attributed to the strict coordination of viral gene expression with the differentiation stage of the infected cell. HPV gene expression is regulated temporally at the level of RNA splicing and polyadenylation, and a dysregulated gene expression programme allows some HPV types to establish long-term persistence, which is a risk factor for cancer. In this Review, we summarize the role of splicing and polyadenylation in the regulation of HPV gene expression and discuss the viral and cellular factors that control these processes.
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| 7. |
- Lindås, Ann-Christin, et al.
(författare)
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The cell cycle of archaea
- 2013
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 11:9, s. 627-638
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Forskningsöversikt (refereegranskat)abstract
- Growth and proliferation of all cell types require intricate regulation and coordination of chromosome replication, genome segregation, cell division and the systems that determine cell shape. Recent findings have provided insight into the cell cycle of archaea, including the multiple-origin mode of DNA replication, the initial characterization of a genome segregation machinery and the discovery of a novel cell division system. The first archaeal cytoskeletal protein, crenactin, was also recently described and shown to function in cell shape determination. Here, we outline the current understanding of the archaeal cell cycle and cytoskeleton, with an emphasis on species in the genus Sulfolobus, and consider the major outstanding questions in the field.
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| 8. |
- Makarova, Kira S, et al.
(författare)
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Evolution and classification of the CRISPR-Cas systems
- 2011
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Ingår i: Nature Reviews Microbiology. - : Nature Publishing Group. - 1740-1526 .- 1740-1534. ; 9:6, s. 467-477
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Tidskriftsartikel (refereegranskat)abstract
- The CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) modules are adaptive immunity systems that are present in many archaea and bacteria. These defence systems are encoded by operons that have an extraordinarily diverse architecture and a high rate of evolution for both the cas genes and the unique spacer content. Here, we provide an updated analysis of the evolutionary relationships between CRISPR-Cas systems and Cas proteins. Three major types of CRISPR-Cas system are delineated, with a further division into several subtypes and a few chimeric variants. Given the complexity of the genomic architectures and the extremely dynamic evolution of the CRISPR-Cas systems, a unified classification of these systems should be based on multiple criteria. Accordingly, we propose a 'polythetic' classification that integrates the phylogenies of the most common cas genes, the sequence and organization of the CRISPR repeats and the architecture of the CRISPR-cas loci.
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| 9. |
- McGuckin, MA, et al.
(författare)
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Mucin Dynamics and Enteric Pathogens
- 2011
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 9:4, s. 265-78
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Forskningsöversikt (refereegranskat)abstract
- Abstract: The extracellular secreted mucus and the cell surface glycocalyx prevent infection by the vast numbers of microorganisms that live in the healthy gut. Mucin glycoproteins are the major component of these barriers. In this Review, we describe the components of the secreted and cell surface mucosal barriers and the evidence that they form an effective barricade against potential pathogens. However, successful enteric pathogens have evolved strategies to circumvent these barriers. We discuss the interactions between enteric pathogens and mucins, and the mechanisms that these pathogens use to disrupt and avoid mucosal barriers. In addition, we describe dynamic alterations in the mucin barrier that are driven by host innate and adaptive immune responses to infection.
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| 10. |
- Philippot, Laurent, et al.
(författare)
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The ecological coherence of high bacterial taxonomic ranks
- 2010
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Ingår i: Nature Reviews Microbiology. - : Springer Science and Business Media LLC. - 1740-1526 .- 1740-1534. ; 8:7, s. 523-529
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Forskningsöversikt (refereegranskat)abstract
- The species is a fundamental unit of biological organization, but its relevance for Bacteria and Archaea is still hotly debated. Even more controversial is whether the deeper branches of the ribosomal RNA-derived phylogenetic tree, such as the phyla, have ecological importance. Here, we discuss the ecological coherence of high bacterial taxa in the light of genome analyses and present examples of niche differentiation between deeply diverging groups in terrestrial and aquatic systems. The ecological relevance of high bacterial taxa has implications for bacterial taxonomy, evolution and ecology.
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