| 1. |
- Andersson, Jan O, et al.
(författare)
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A century of typhus, lice and Rickettsia
- 2000
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Ingår i: Research in Microbiology. - : EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER. - 0923-2508 .- 1769-7123. ; 151:2, s. 143-150
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Tidskriftsartikel (refereegranskat)abstract
- At the beginning of the 20th century, it was discovered at the Pasteur Institute in Tunis that epidemic typhus is transmitted by the human body louse. The complete genome sequence of its causative agent, Rickettsia prowazekii, was determined at Uppsala University in Sweden at the end of the century. In this mini-review, we discuss insights gained from the genome sequence of this fascinating and deadly organism.
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| 2. |
- Naumov, Gennadi I., et al.
(författare)
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Genetic characterization of the nonconventional yeast Hansenula anomala
- 2001
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Ingår i: Research in Microbiology. - : Elsevier. - 0923-2508 .- 1769-7123. ; 152:6, s. 551-562
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Tidskriftsartikel (refereegranskat)abstract
- We describe genetic, molecular and taxonomic characteristics of the yeast Hansenula anomala. Pulsed-field gel electrophoresis of chromosomal DNAs from 19 H. anomala strains and related species indicated that H. anomala had a clearly different karyotype. Chromosome length polymorphism of the H. anomala strains was independent of their geographic origin and source of isolation. The strains were classified into four groups of similar karyotypes and one strain showed a unique profile. The sizes of chromosomes ranged from 850 to 3500 kb in different strains. The haploid chromosome number of H. anomala is at least nine. We have found RAPD primers discriminating at both the species and strain levels. All the primers tested except the M13 core sequence generated unique patterns with most strains. The results indicate the usefulness of PCR analysis with primer M13 for identification of the H. anomala species. Screening of the CBS (Utrecht) collection strains of H. anomala showed that they are rather difficult objects for genetic hybridization analysis. The strains have low fertility, viz. very poor sporulation, low mating type activities and, as a rule, nonviable ascospores. The majority of the hybrids obtained are polyploid, probably tetraploid, as judged by the segregation of control auxotrophic markers. Nevertheless, some monosporic cultures of the strains studied, including the biocontrol yeast J121, formed diploid hybrids with regular meiotic segregation of control auxotrophic markers. As a rule, H. anomala isolates are homothallic, showing delayed self-diploidization. Rare stable heterothallic strains of H. anomala also occur.
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| 3. |
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| 4. |
- Campos, Manuel, et al.
(författare)
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The type II secretion system : a dynamic fiber assembly nanomachine
- 2013
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Ingår i: Research in Microbiology. - : Elsevier BV. - 0923-2508 .- 1769-7123. ; 164:6, s. 545-555
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Tidskriftsartikel (refereegranskat)abstract
- Type II secretion systems (T2SSs) share common origins and structure with archaeal flagella (archaella) and pili, bacterial competence systems and type IV pili. All of these systems use a conserved ATP-powered machinery to assemble helical fibers that are anchored in the plasma membrane. The T2SSs assemble pseudopili, periplasmic filaments that promote extracellular secretion of folded periplasmic proteins. Comparative analysis of T2SSs and related fiber assembly nanomachines might provide important clues on their functional specificities and dynamics. This review focuses on recent developments in the study of pseudopilus structure and biogenesis, and discusses mechanistic models of pseudopilus function in protein secretion.
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| 5. |
- Christel, Stephan, et al.
(författare)
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Comparison of Boreal Acid Sulfate Soil Microbial Communities in Oxidative and Reductive Environments
- 2019
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Ingår i: Research in Microbiology. - : Elsevier. - 0923-2508 .- 1769-7123. ; 170:6-7, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- Due to land uplift after the last ice age, previously stable Baltic Sea sulfidic sediments are becoming dry land. When these sediments are drained, the sulfide minerals are exposed to air and can release large amounts of metals and acid into the environment. This can cause severe ecological damage such as fish kills in rivers feeding the northern Baltic Sea. In this study, five sites were investigated for the occurrence of acid sulfate soils and their geochemistry and microbiology was identified. The pH and soil chemistry identified three of the areas as having classical acid sulfate soil characteristics and culture independent identification of 16S rRNA genes identified populations related to acidophilic bacteria capable of catalyzing sulfidic mineral dissolution, including species likely adapted to low temperature. These results were compared to an acid sulfate soil area that had been flooded for ten years and showed that the previously oxidized sulfidic materials had an increased pH compared to the unremediated oxidizied layers. In addition, the microbiology of the flooded soil had changed such that alkalinity producing ferric and sulfate reducing reactions had likely occurred. This suggested that flooding of acid sulfate soils mitigates their environmental impact.
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| 6. |
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| 7. |
- Fuxelius, Hans-Henrik, et al.
(författare)
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The genomic and metabolic diversity of Rickettsia
- 2007
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Ingår i: Research in Microbiology. - : Elsevier BV. - 0923-2508 .- 1769-7123. ; 158:10, s. 745-753
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Tidskriftsartikel (refereegranskat)abstract
- Comparative genomics of Rickettsia and Orientia has revealed an exciting interplay between reductive evolutionary forces acting on metabolic genes in all species and proliferation of mobile genetic elements in some species. These contradictory evolutionary forces highlight the influence of chance, adaptation and host-cell exploitation during the evolution of intracellular bacteria.
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| 8. |
- Goncalves, Odete Sofia Lopes, et al.
(författare)
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The repeated 36 amino acid motif of Chlamydia trachomatis Hc2 protein binds to the major groove of DNA
- 2019
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Ingår i: Research in Microbiology. - : ELSEVIER. - 0923-2508 .- 1769-7123. ; 170:6-7, s. 256-262
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Tidskriftsartikel (refereegranskat)abstract
- The gram-negative, obligate intracellular human pathogen, Chlamydia trachomatis has a bi-phasic developmental cycle. The histone H1-like C. trachomatis DNA binding protein, Hc2, is produced late during the developmental cycle when the dividing reticulate body transforms into the smaller, metabolically inactive elementary body. Together with Hc1, the two proteins compact the chlamydial chromosome and arrest replication and transcription. Hc2 is heterogeneous in length due to variation in the number of lysine rich pentamers. Six pentamers and one hexamer constitute a 36 amino acid long repetitive unit that, in spite of variations, is unique for Chlamydiaceae. Using synthetic peptides, the DNA-binding capacity of the 36 amino acid peptide and that of a randomized peptide was analyzed. Both peptides bound and compacted plasmid DNA, however, electron microscopy of peptide/DNA complexes showed major differences in the resulting aggregated structures. Fluorescence spectroscopy was used to analyze the binding. After complexing plasmid DNA with each of three different intercalating dyes, increasing amounts of peptides were added and fluorescence spectroscopy performed. The major groove binder, methyl green, was displaced by both peptides at low concentrations, while the minor groove binder, Hoechts, and the intercalating dye, Ethidium Bromide, were displaced only at high concentrations of peptides. (C) 2019 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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| 9. |
- González, Carolina, et al.
(författare)
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Genetic variability of psychrotolerant Acidithiobacillus ferrivorans revealed by (meta)genomic analysis.
- 2014
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Ingår i: Research in Microbiology. - : Elsevier BV. - 0923-2508 .- 1769-7123. ; 165:9, s. 726-734
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Tidskriftsartikel (refereegranskat)abstract
- Acidophilic microorganisms inhabit low pH environments such as acid mine drainage that is generated when sulfide minerals are exposed to air. The genome sequence of the psychrotolerant Acidithiobacillus ferrivorans SS3 was compared to a metagenome from a low temperature acidic stream dominated by an A. ferrivorans-like strain. Stretches of genomic DNA characterized by few matches to the metagenome, termed 'metagenomic islands', encoded genes associated with metal efflux and pH homeostasis. The metagenomic islands were enriched in mobile elements such as phage proteins, transposases, integrases and in one case, predicted to be flanked by truncated tRNAs. Cus gene clusters predicted to be involved in copper efflux and further Cus-like RND systems were predicted to be located in metagenomic islands and therefore, constitute part of the flexible gene complement of the species. Phylogenetic analysis of Cus clusters showed both lineage specificity within the Acidithiobacillus genus as well as niche specificity associated with an acidic environment. The metagenomic islands also contained a predicted copper efflux P-type ATPase system and a polyphosphate kinase potentially involved in polyphosphate mediated copper resistance. This study identifies genetic variability of low temperature acidophiles that likely reflects metal resistance selective pressures in the copper rich environment.
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| 10. |
- Grones, Peter
(författare)
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Characterization of newly identified DnaA and DnaB proteins from Acetobacter
- 2016
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Ingår i: Research in Microbiology. - : Elsevier BV. - 0923-2508 .- 1769-7123. ; 167, s. 655-668
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Tidskriftsartikel (refereegranskat)abstract
- Although chromosomal replication is an essential feature of the bacterial life cycle, the replication mechanism and involved molecular players have never been properly characterized in the Acetobacter genera. Thanks to whole-genome sequencing, the unknown replication proteins from Acetobacter pasteurianus and Acetobacter orleanensis, DnaA-like and DnaB-like, could be identified. Despite the low nucleotide or amino acid similarity to the respective orthologs from Escherichia coli, their involvement during replication regulation was corroborated by artificial microRNA. In the Acetobacter genome, a novel replication origin, oriAo, was detected with three 9-nucleotide-long DnaA boxes to which DnaA-like proteins bind actively. Bacterial two-hybrid systems and co-immunoprecipitation confirmed the homologous and heterologous interactions between DnaA-like and DnaB-like proteins with their E. coli orthologs. This communication is due to the conserved tryptophan at position 6 for E. coli or 25 for Acetobacter that unables DnaA-like proteins to form oligomeric protein structures after its substitution. Altogether, these results provide novel insights into the genome replication mechanism in Acetobacter. (C) 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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