| 1. |
- Murphy, Elizabeth, et al.
(författare)
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Gram-positive anaerobic cocci - commensals and opportunistic pathogens.
- 2013
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 1574-6976. ; 37:4, s. 520-553
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Forskningsöversikt (refereegranskat)abstract
- Among the Gram-positive anaerobic bacteria associated with clinical infections, the Gram-positive anaerobic cocci (GPAC) are the most prominent and account for approximately 25-30% of all isolated anaerobic bacteria from clinical specimens. Still, routine culture and identification of these slowly growing anaerobes to the species level has been limited in the diagnostic laboratory, mainly due to the requirement of prolonged incubation times and time-consuming phenotypic identification. In addition, GPAC are mostly isolated from polymicrobial infections with known pathogens and therefore their relevance has often been overlooked. However, through improvements in diagnostic and in particular molecular techniques, the isolation and identification of individual genera and species of GPAC associated with specific infections have been enhanced. Furthermore, the taxonomy of GPAC has undergone considerable changes over the years, mainly due to the development of molecular identification methods. Existing species have been renamed and novel species have been added, resulting in changes of the nomenclature. As the abundance and significance of GPAC in clinical infections grow, knowledge of virulence factors and antibiotic resistance patterns of different species becomes more important. The present review describes recent advances of GPAC and what is known of the biology and pathogenic effects of Anaerococcus, Finegoldia, Parvimonas, Peptoniphilus and Peptostreptococcus, the most important GPAC genera isolated from human infections. © 2012 Federation of European Microbiological Societies. Published by BlackwellPublishing Ltd. All rights reserved.
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| 2. |
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| 3. |
- McCormick, Joseph R., et al.
(författare)
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Signals and regulators that govern Streptomyces development
- 2012
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 1574-6976. ; 36:1, s. 206-231
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Forskningsöversikt (refereegranskat)abstract
- Streptomyces coelicolor is the genetically best characterized species of a populous genus belonging to the gram-positive Actinobacteria. Streptomycetes are filamentous soil organisms, well known for the production of a plethora of biologically active secondary metabolic compounds. The Streptomyces developmental life cycle is uniquely complex and involves coordinated multicellular development with both physiological and morphological differentiation of several cell types, culminating in the production of secondary metabolites and dispersal of mature spores. This review presents a current appreciation of the signaling mechanisms used to orchestrate the decision to undergo morphological differentiation, and the regulators and regulatory networks that direct the intriguing development of multigenomic hyphae first to form specialized aerial hyphae and then to convert them into chains of dormant spores. This current view of S. coelicolor development is destined for rapid evolution as data from -omics studies shed light on gene regulatory networks, new genetic screens identify hitherto unknown players, and the resolution of our insights into the underlying cell biological processes steadily improve.
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| 4. |
- Pedersen, Karsten, 1952
(författare)
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Microbial life in deep granitic rock
- 1997
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 0168-6445 .- 1574-6976. ; 20:3-4, s. 399-414
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Forskningsöversikt (refereegranskat)
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| 5. |
- Singh, Birendra, et al.
(författare)
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Human pathogens utilize host extracellular matrix proteins laminin and collagen for adhesion and invasion of the host.
- 2012
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 1574-6976. ; 36:6, s. 1122-1180
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Tidskriftsartikel (refereegranskat)abstract
- Laminin (Ln) and collagen are multifunctional glycoproteins that play an important role in cellular morphogenesis, cell signaling, tissue repair and cell migration. These proteins are ubiquitously present in tissues as a part of the basement membrane (BM), constitute a protective layer around blood capillaries, and are included in the extracellular matrix (ECM). As a component of BMs, both Lns and collagen(s) are found in the blood-brain barrier, and thus function as major mechanical containment molecules that protect tissues from pathogens. Invasive pathogens breach the basal lamina and degrade ECM proteins of interstitial spaces and connective tissues by using various ECM degrading proteases or surface-bound plasminogen and matrix metalloproteinases recruited from the host. Most pathogens associated with the respiratory, gastrointestinal, or urogenital tracts, as well as the CNS or the skin have the capacity to bind and degrade Lns and collagen(s) in order to adhere to and invade host tissues. In this review we focus on the adaptability of various pathogens to utilize these ECM proteins as enhancers for adhesion to host tissues or as a targets for degradation in order to breach the cellular barriers. The major pathogens discussed are Streptococcus, Staphylococcus, Pseudomonas, Salmonella, Yersinia, Treponema, Mycobacterium, Clostridium, Listeria, Porphyromonas and Haemophilus; Candida, Aspergillus, Pneumocystis, Cryptococcus and Coccidioides; Acanthamoeba, Trypanosoma and Trichomonas; Retrovirus and papilloma virus © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
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| 6. |
- Omsland, Anders, et al.
(författare)
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Chlamydial metabolism revisited : interspecies metabolic variability and developmental stage-specific physiologic activities
- 2014
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 0168-6445 .- 1574-6976. ; 38:4, s. 779-801
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Tidskriftsartikel (refereegranskat)abstract
- Chlamydiae are a group of obligate intracellular bacteria comprising important human and animal pathogens as well as symbionts of ubiquitous protists. They are characterized by a developmental cycle including two main morphologically and physiologically distinct stages, the replicating reticulate body and the infectious nondividing elementary body. In this review, we reconstruct the history of studies that have led to our current perception of chlamydial physiology, focusing on their energy and central carbon metabolism. We then compare the metabolic capabilities of pathogenic and environmental chlamydiae highlighting interspecies variability among the metabolically more flexible environmental strains. We discuss recent findings suggesting that chlamydiae may not live as energy parasites throughout the developmental cycle and that elementary bodies are not metabolically inert but exhibit metabolic activity under appropriate axenic conditions. The observed host-free metabolic activity of elementary bodies may reflect adequate recapitulation of the intracellular environment, but there is evidence that this activity is biologically relevant and required for extracellular survival and maintenance of infectivity. The recent discoveries call for a reconsideration of chlamydial metabolism and future in-depth analyses to better understand how species- and stage-specific differences in chlamydial physiology may affect virulence, tissue tropism, and host adaptation.
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| 7. |
- Andersson, Dan I., et al.
(författare)
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Persistence of antibiotic resistance in bacterial populations
- 2011
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 0168-6445 .- 1574-6976. ; 35:5, s. 901-911
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Forskningsöversikt (refereegranskat)abstract
- Unfortunately for mankind, it is very likely that the antibiotic resistance problem we have generated during the last 60 years due to the extensive use and misuse of antibiotics is here to stay for the foreseeable future. This view is based on theoretical arguments, mathematical modeling, experiments and clinical interventions, suggesting that even if we could reduce antibiotic use, resistant clones would remain persistent and only slowly (if at all) be outcompeted by their susceptible relatives. In this review, we discuss the multitude of mechanisms and processes that are involved in causing the persistence of chromosomal and plasmid-borne resistance determinants and how we might use them to our advantage to increase the likelihood of reversing the problem. Of particular interest is the recent demonstration that a very low antibiotic concentration can be enriching for resistant bacteria and the implication that antibiotic release into the environment could contribute to the selection for resistance.
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| 8. |
- Bergman, Birgitta, et al.
(författare)
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Trichodesmium : a widespread marine cyanobacterium with unusual nitrogen fixation properties
- 2013
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 0168-6445 .- 1574-6976. ; 37:3, s. 286-302
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Forskningsöversikt (refereegranskat)abstract
- The last several decades have witnessed dramatic advances in unfolding the diversity and commonality of oceanic diazotrophs and their N(2) -fixing potential. More recently substantial progress in diazotrophic cell biology has provided a wealth of information on processes and mechanisms involved. The substantial contribution by the diazotrophic cyanobacterial genus Trichodesmium to the nitrogen influx of the global marine ecosystem is by now undisputable and of paramount ecological importance, while the underlying cellular and molecular regulatory physiology has only recently started to unfold. Here we explore and summarize current knowledge, related to optimization of its diazotrophic capacity, from genomics to ecophysiological processes, via eg. cellular differentiation (diazocytes) and temporal regulations, and suggest cellular research avenues that now ought to be explored. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
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| 9. |
- Shingler, Victoria
(författare)
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Signal sensory systems that impact σ(54)-dependent transcription
- 2011
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Ingår i: FEMS Microbiology Reviews. - : Oxford University Press (OUP). - 0168-6445 .- 1574-6976. ; 35:3, s. 425-440
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Tidskriftsartikel (refereegranskat)abstract
- Alternative σ-factors of bacteria bind core RNA polymerase to program the specific promoter selectivity of the holoenzyme. Signal-responsive changes in the availability of different σ-factors redistribute the RNA polymerase among the distinct promoter classes in the genome for appropriate adaptive, developmental and survival responses. The σ(54) -factor is structurally and functionally distinct from all other σ-factors. Consequently, binding of σ(54) to RNA polymerase confers unique features on the cognate holoenzyme, which requires activation by an unusual class of mechano-transcriptional activators, whose activities are highly regulated in response to environmental cues. This review summarizes the current understanding of the mechanisms of transcriptional activation by σ(54) -RNA polymerase and highlights the impact of global regulatory factors on transcriptional efficiency from σ(54) -dependent promoters. These global factors include the DNA-bending proteins IHF and CRP, the nucleotide alarmone ppGpp, and the RNA polymerase-targeting protein DksA.
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| 10. |
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