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  • 1. Gustafsson, Erik
    et al.
    Oscarsson, Jan
    Umeå University, Faculty of Medicine, Odontology. Umeå University, Faculty of Medicine, Odontology, Oral Microbiology.
    Maximal transcription of aur (aureolysin) and sspA (serine protease) in Staphylococcus aureus requires staphylococcal accessory regulator R (sarR) activity.2008In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 284, no 2, 158-64 p.Article in journal (Refereed)
    Abstract [en]

    Previous studies have shown that expression of aur (metalloprotease; aureolysin) and sspA (V8 protease; serine protease) in Staphylococcus aureus strain 8325-4 is maximal in the postexponential phase of growth, when the agr (RNAIII) system is activated. Transcription of aur and sspA is mainly regulated through repression by sarA and rot, and RNAIII stimulates protease production by inhibiting translation of rot mRNA. As SarR is a repressor of sarA, inactivation of sarR would result in downregulation of aur and sspA transcription. This was confirmed by mRNA analysis using quantitative real-time PCR. However, we found that sarR acted as a direct stimulator, i.e. its positive effect on aur and sspA transcription did not require sarA (or rot) per se. In addition, aur and sspA were dependent on sarR for maximal transcription. This stimulating role of sarR was not restricted to the rsbU-deficient laboratory strain 8325-4 but was also demonstrated in S. aureus strain SH1000 (rsbU-complemented derivative of 8325-4) and in one clinical isolate.

  • 2.
    Lai, Xin-He
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Wang, S-Y
    Umeå University, Faculty of Medicine, Molecular Biology.
    Edebro, Helene
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Sjöstedt, Anders
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology.
    Francisella strains express hemolysins of distinct characteristics2003In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 224, no 1, 91-95 p.Article in journal (Refereed)
    Abstract [en]

    Historically, Francisella strains have been described as nonhemolytic. In this study, we show by use of solid and liquid hemolysis assays that some Francisella strains have hemolytic properties. The Francisella novicida type strain U112 is hemolytic to horse erythrocytes and Francisella philomiragia type strain FSC144 is hemolytic towards both human and horse erythrocytes. The F. novicida strain U112 released a protein (novilysin A) into the culture supernatant which cross-reacted with antiserum against Escherichia coli HlyA whereas there was no similar protein detectable with this cross-reactive property from the supernatant of the F. philomiragia strain.

  • 3. Leitz, G
    et al.
    Lundberg, C
    Fallman, E
    Axner, O
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Laser-based micromanipulation for separation and identification of individual Frankia vesicles2003In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 224, no 1, 97-100 p.Article in journal (Refereed)
    Abstract [en]

    In studies of symbiotic efficiency it is of great importance to identify and separate individual Frankia strains from a nodule. Therefore, a new laser-based micromanipulation technique has been developed in which individual vesicles from root nodules of two Frankia-Alnus symbioses have been successfully cut loose and separated from clusters of vesicles in sterile conditions under light microscopy using a laser scalpel and optical tweezers. Vesicles from the Alnus incana-Frankia AvCIl symbiosis were successfully isolated and grown in culture using this technique. The DNA from both Frankia sources was amplified by polymerase chain reaction (PCR). The work shows that a combination of laser-based manipulation techniques and PCR can be used for the separation and study of individual vesicles. This novel laser-based micromanipulation technique opens up various new possibilities, for instance, to study whether several Frankia strains can grow simultaneously in the same root nodule. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

  • 4. LINDBLAD, P
    et al.
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    IMMUNOGOLD LOCALIZATION OF HYDROGENASE IN FREE-LIVING FRANKIA CPI11989In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 60, no 3, 311-315 p.Article in journal (Refereed)
  • 5.
    Mohapatra, Anasuya
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Leul, Melakeselam
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Mattsson, Ulrika
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    A hydrogen-evolving enzyme is present in Frankia sp. R432004In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 236, no 2, 235-240 p.Article in journal (Refereed)
    Abstract [en]

    The ability to evolve hydrogen using methyl viologen as an electron donor was assayed in the nitrogen-fixing actinomycetes Frankia sp. R43 and Frankia sp. KB5. To further examine the nature of hydrogen-evolving enzymes that may be present in these organisms immunological studies were performed. Under anaerobic conditions (both nitrogen-limiting and nitrogen-containing) Frankia sp. R43 but not Frankia sp. KB5 evolved hydrogen,which was not linked to NAD-reducing activity. Immunological analysis of total protein from Frankia sp. R43 and Frankia sp. KB5 using an antiserum raised against Ralstonia eutropha HoxF, recognized an antigen in Frankia sp. R43 but not in Frankia sp. KB5. Immunogold labeling using antibodies raised against the R. eutropha HoxH recognized sites in both hyphae and vesicles of Frankia sp. R43, but not in Frankia sp. KB5. Based on these physiological and immunological findings, we conclude that Frankia sp. R43 has a hydrogen-evolving hydrogenase.

  • 6. Nancucheo, Ivan
    et al.
    Rowe, Owen F.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, Viikki Biocenter 1, University of Helsinki, Helsinki, Finland.
    Hedrich, Sabrina
    Johnson, D. Barrie
    Solid and liquid media for isolating and cultivating acidophilic and acid-tolerant sulfate-reducing bacteria2016In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 363, no 10, fnw083Article in journal (Refereed)
    Abstract [en]

    Growth media have been developed to facilitate the enrichment and isolation of acidophilic and acid-tolerant sulfate-reducing bacteria (aSRB) from environmental and industrial samples, and to allow their cultivation in vitro. The main features of the 'standard' solid and liquid devised media are as follows: (i) use of glycerol rather than an aliphatic acid as electron donor; (ii) inclusion of stoichiometric concentrations of zinc ions to both buffer pH and to convert potentially harmful hydrogen sulphide produced by the aSRB to insoluble zinc sulphide; (iii) inclusion of Acidocella aromatica (an heterotrophic acidophile that does not metabolize glycerol or yeast extract) in the gel underlayer of double layered (overlay) solid media, to remove acetic acid produced by aSRB that incompletely oxidize glycerol and also aliphatic acids (mostly pyruvic) released by acid hydrolysis of the gelling agent used (agarose). Colonies of aSRB are readily distinguished from those of other anaerobes due to their deposition and accumulation of metal sulphide precipitates. Data presented illustrate the effectiveness of the overlay solid media described for isolating aSRB from acidic anaerobic sediments and low pH sulfidogenic bioreactors.

  • 7. Pallen, Mark J
    et al.
    Francis, Matthew S
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Fütterer, Klaus
    Tetratricopeptide-like repeats in type-III-secretion chaperones and regulators2003In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 223, no 1, 53-60 p.Article in journal (Refereed)
    Abstract [en]

    Efficient type-III secretion depends on cytosolic molecular chaperones, which bind specifically to the translocators and effectors. In the past there has been a tendency to shoe-horn all type-III-secretion chaperones into a single structural and functional class. However, we have shown that the LcrH/SycD-like chaperones consist of three central tetratricopeptide-like repeats that are predicted to fold into an all-alpha-helical array that is quite distinct from the known structure of the SycE class of chaperones. Furthermore, we predict that this array creates a peptide-binding groove that is utterly different from the helix-binding groove in SycE. We present a homology model of LcrH/SycD that is consistent with existing mutagenesis data. We also report the existence of tetratricopeptide-like repeats in regulators of type-III secretion, such as HilA from Salmonella enterica and HrpB from Ralstonia solanacearum. The discovery of tetratricopeptide-like repeats in type-III-secretion regulators and chaperones provides a new conceptual framework for structural and mutagenesis studies and signals a potential unification of prokaryotic and eukaryotic chaperone biology.

  • 8.
    Sellstedt, Anita
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    SPECIFICITY AND EFFECTIVITY IN NODULATION BY FRANKIA ON SOUTHERN-HEMISPHERE ACTINORHIZA1995In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 125, no 2-3, 231-236 p.Article in journal (Refereed)
    Abstract [en]

    Nodulation ability was tested for Frankia strains HFPCcI3 and EL1, and Frankia sources A.t. and G.a. from Allocasuarina torulosa and Gymnostoma australianum, respectively, on A. torulosa Mig., Casuarina cunninghamiana Mig., G. australianum L. Johnson and Elaeagnus triflora Roxb. It was shown that A. torulosa and C. cunninghamiana formed nodules only with the Frankia sources obtained from their own host plant, while E. triflora formed nodules with three of the four Frankia sources tested. All nodules formed were effectively fixing nitrogen. Specific nitrogenase activity was highest in E. triflora inoculated with the Frankia strain isolated from nodules of the same species. Identification of Frankia sources in the nodules was performed by use of PCR amplification of DNA with a random primer. PCR amplification of DNA isolated from nodules of G. australianum and E. triflora inoculated with Frankia strain EL1 revealed, when compared with DNA amplified from free living Frankia strain EL1, that there was only one Frankia strain causing the observed nodules.

  • 9.
    Sellstedt, Anita
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Richau, Kerstin
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Aspects of nitrogen-fixing Actinobacteria, in particular free-living and symbiotic Frankia2013In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 342, no 2, 179-186 p.Article, review/survey (Refereed)
    Abstract [en]

    Studies of nitrogen-fixing properties among the Gram-positive Actinobacteria revealed that some species of Arthrobacter, Agromyces, Corynebacterium, Mycobacterium, Micromonospora, Propionibacteria and Streptomyces have nitrogen-fixing capacity. This is also valid for Frankia that fix nitrogen both in free-living and in symbiotic conditions. Frankia symbiosis results from interaction between the Frankia bacteria and dicotyledonous plants, that is, actinorhiza. These plants, which are important in forestry and agroforestry, form, together with the legumes (Fabales), a single nitrogen-fixing clade. It has been shown that a receptor-like kinase gene, SymRK, is necessary for nodulation in actinorhizal plants as well as in legumes and arbuscular mycorrhizal fungi. Recently, the involvement of isoflavonoids as signal molecules during nodulation of an actinorhizal plant was shown. The genome sizes of three Frankia species, Frankia EANpec, ACN14a and CcI3, are different, revealing a relationship between genome size and geographical distribution. Recent genomic sequencing data of Frankia represent genomes from cluster I to IV, indicating that the genome of DgI is one of the smallest genomes in Frankia. In addition, nonsymbiotic Frankiales such as Acidothermus cellulolyticus, Blastococcus saxoobsidens, Geodermatophilus obscurus and Modestobacter marinus have a variety of genome sizes ranging from 2.4 to 5.57Mb.

  • 10.
    Sellstedt, Anita
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    WULLINGS, B
    NYSTROM, U
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    IDENTIFICATION OF CASUARINA-FRANKIA STRAINS BY USE OF POLYMERASE CHAIN-REACTION (PCR) WITH ARBITRARY PRIMERS1992In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 93, no 1, 1-5 p.Article in journal (Refereed)
    Abstract [en]

    Free-living N2-fixing Frankia strains isolated from Casuarina sp. were investigated for genomic polymorphism. We used six 10-mer oligonucleotides as single arbitrary primers (AP) for the polymerase chain reaction (PCR) in order to amplify random DNA fragments in the genome of free-living Frankia strains. Agarose-gels of the amplified genomic DNA revealed that two of the six arbitrary primers showed polymorphism in the eight different Frankia genomes. Analysis of the AP-PCR products showed 9 polymorphic bands ranging from 4.1-0.60 kb. We conclude that single arbitrary primers can be used to amplify genomic DNA, and that polymorphism can be detected between the amplification products of the different Frankia genomes.

  • 11.
    Sellstedt, Anita
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    WULLINGS, B
    NYSTROM, U
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    IDENTIFICATION OF CASUARINA-FRANKIA STRAINS BY USE OF POLYMERASE CHAIN-REACTION (PCR) WITH ARBITRARY PRIMERS1992In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 93, no 1, 1-5 p.Article in journal (Refereed)
    Abstract [en]

    Free-living N2-fixing Frankia strains isolated from Casuarina sp. were investigated for genomic polymorphism. We used six 10-mer oligonucleotides as single arbitrary primers (AP) for the polymerase chain reaction (PCR) in order to amplify random DNA fragments in the genome of free-living Frankia strains. Agarose-gels of the amplified genomic DNA revealed that two of the six arbitrary primers showed polymorphism in the eight different Frankia genomes. Analysis of the AP-PCR products showed 9 polymorphic bands ranging from 4.1-0.60 kb. We conclude that single arbitrary primers can be used to amplify genomic DNA, and that polymorphism can be detected between the amplification products of the different Frankia genomes.

  • 12. Turkina, Maria V.
    et al.
    Olofsson, Annelie
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Magnusson, Karl-Eric
    Arnqvist, Anna
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vikstrom, Elena
    Helicobacter pylori vesicles carrying CagA localize in the vicinity of cell-cell contacts and induce histone H1 binding to ATP in epithelial cells2015In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 362, no 11, fnv076Article in journal (Refereed)
    Abstract [en]

    Helicobacter pylori produces outer membrane vesicles (OMV), delivering bacterial substances including the oncogenic cytotoxin-associated CagA protein to their surroundings. We investigated the effects of H. pylori OMV carrying CagA (OMV-CagA) on cell junctions and ATP-binding proteome of epithelial monolayers, using proteomics, mass spectrometry and imaging. OMV-CagA localized in close vicinity of ZO-1 tight junction protein and induced histone H1 binding to ATP. We suggest the expression of novel events in the interactions between H. pylori OMV and epithelia, which may have an influence on host gene transcription and lead to different outcomes of an infection and development of cancer.

  • 13.
    Zeng, Qing-Yin
    et al.
    Umeå University, Faculty of Science and Technology, Molecular Biology (Faculty of Science and Technology).
    Rasmuson-Lestander, Åsa
    Umeå University, Faculty of Science and Technology, Molecular Biology (Faculty of Science and Technology).
    Wang, Xiao-Ru
    Extensive set of mitochondrial LSU rDNA-based oligonucleotide probes for the detection of common airborne fungi.2004In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 237, no 1, 79-87 p.Article in journal (Refereed)
    Abstract [en]

    Fungi exist in every indoor and outdoor environment. Many fungi are toxigenic or pathogens that may cause various public health concerns. Rapid and accurate detection and identification of fungi require specific markers. In this study, partial mitochondrial large subunit rDNA was amplified and sequenced from 32 fungal strains representing 31 species from 14 genera. Based on the sequence variation pattern, 26 oligonucleotide probes were designed for their discrimination. The specificity of the probes was evaluated through homology search against GenBank database and hybridization examination on 38 fungal strains. The 26 probes were verified as highly specific to 20 fungal species. A two-step detection procedure through PCR followed by probe hybridization gave ten-fold increase in detection sensitivity than single-step PCR assay and would be a practical approach for environmental sample screening. The probes developed in this study can be applied in clinical diagnosis and environmental monitoring of fungal agents.

  • 14.
    Östberg, Yngve
    et al.
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Berg, Stefan
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Comstedt, Pär
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Wieslander, Åke
    Bergström, Sven
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Functional analysis of a lipid galactosyltransferase synthesizing the major envelope lipid in the Lyme disease spirochete Borrelia burgdorferi2007In: FEMS Microbiology Letters, ISSN 0378-1097, E-ISSN 1574-6968, Vol. 272, no 1, 22-29 p.Article in journal (Refereed)
    Abstract [en]

    One of the major lipids in the membranes of Borrelia burgdorferi is monogalactosyl diacylglycerol (MGalDAG), a glycolipid recently shown to carry antigenic potency. Herein, it is shown that the gene mgs (TIGR designation bb0454) of B. burgdorferi encodes for the protein bbMGS that, when expressed in Escherichia coli, catalyzes the glycosylation of 1,2-diacylglycerol with specificity for the donor substrate UDP-Gal yielding MGalDAG. Related lipid enzymes were found in many Gram-positive bacteria. The presence of this galactosyltransferase activity and synthesis of a cholesteryl galactoside by another enzyme were verified in B. burgdorferi cell extract. Besides MGalDAG, phosphatidylcholine, phosphatidylglycerol, and cholesterol were also found as major lipids in the cell envelope. The high isoelectric point of bbMGS and clustered basic residues in its amino acid sequence suggest that the enzyme interacts with acidic lipids in the plasma membrane, in agreement with strong enzymatic activation of bbMGS by phosphatidylglycerol. The membrane packing and immunological properties of MGalDAG are likely to be of great importance in vivo.

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