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  • 1.
    Ast, Jennifer C
    et al.
    University of Michigan, Department of Ecology and Evolutionary Biology.
    Dunlap, Paul V
    University of Michigan, Department of Ecology and Evolutionary Biology.
    Phylogenetic analysis of the lux operon distinguishes two evolutionarily distinct clades of Photobacterium leiognathi.2004In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 181, no 5, p. 352-61Article in journal (Refereed)
    Abstract [en]

    The luminous marine bacterium Photobacterium mandapamensis was synonymized several years ago with Photobacterium leiognathi based on a high degree of phenotypic and genetic similarity. To test the possibility that P. leiognathi as now formulated, however, actually contains two distinct bacterial groups reflecting the earlier identification of P. mandapamensis and P. leiognathi as separate species, we compared P. leiognathi strains isolated from light-organ symbiosis with leiognathid fishes (i.e., ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1) with strains from seawater originally described as P. mandapamensis and later synonymized as P. leiognathi (i.e., ATCC 27561(T) and ATCC 33981) and certain strains initially identified as P. leiognathi (i.e., PL-721, PL-741, 554). Analysis of the 16S rRNA and gyrB genes did not resolve distinct clades, affirming a close relationship among these strains. However, strains ATCC 27561(T), ATCC 33981, PL-721, PL-741 and 554 were found to bear a luxF gene in the lux operon ( luxABFE), whereas ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1 lack this gene ( luxABE). Phylogenetic analysis of the luxAB(F)E region confirmed this distinction. Furthermore, ATCC 27561(T), ATCC 33981, PL-721, PL-741 and 554 all produced a higher level of luminescence on high-salt medium, as previously described for PL-721, whereas ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1 all produced a higher level of luminescence on low-salt medium, a characteristic of P. leiognathi from leiognathid fish light organs. These results demonstrate that P. leiognathi contains two evolutionarily and phenotypically distinct clades, P. leiognathi subsp. leiognathi (strains ATCC 25521(T), ATCC 25587, lequu.1.1 and lleuc.1.1), and P. leiognathi subsp. mandapamensis (strains ATCC 27561(T), ATCC 33981, PL-721, PL-741 and 554).

  • 2. Braune, Wolfram
    et al.
    Ekelund, Nils
    Institutionen för Fysiologisk Botanik, Lunds Universitet.
    Phototactic responses in Haematococcus lacustris and its modification by light intensity and the carotenoid biosynthesis inhibitor Norflurazon1990In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 154, p. 448-452Article in journal (Refereed)
    Abstract [en]

    At fluence rates below 45 W· m-2 cells of the flagellate stage of Haematococcus lacustris react only positively phototactically with a rather high degree of orientation (indicated by r values up to 0.66 with the Rayleigh test). The directedness of orientation decreases with decreasing irradiance. The degree of directedness of the phototactic response depends on the intensity of preirradiation: Low light intensity applied after strong light application results in a dark reaction (low r values), low light given after darkness stimulates a rather high degree of directedness of positive phototaxis. Weak blue light (=483 nm; 0.4 W · m-2) stimulates positive phototactic response, whereas comparable red light (=658 nm; 0.5 W · m-2) does not.

    Cells which were grown in a medium containing 10-4 M Norflurazon (effective in inhibition of carotenoid biosynthesis) although maintaining motility completely lose the ability to react positively phototactically. The possible role of carotenoids in the phototactic orientation is discussed.

  • 3.
    Ekelund, Nils
    Department of Plant Physiology, University of Lund.
    Effects of calcium channel blockers and DCMU on motility and the photophobic response of Gyrodinium dorsum1989In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 151, p. 187-190Article in journal (Refereed)
    Abstract [en]

    The effects of the calcium channel blockers, verapamil, diltiazem and lanthanum ions and the Ca2+ dependency on motility as well as the photophobic response (stop-response) of Gyrodinium dorsum were studied. At Ca2+ concentrations below 10-3 M, motility was inhibited. La3+ inhibits the stop-response, in contrast to verapamil and diltiazem. The only calcium channel blocker that increased the amount of non-motile cells was verapamil. The results indicate that motility are Ca2+ dependent and that the stop-responses of G. dorsum could be affected by extracellular Ca2+. Effects of the photosythesis inhibitor (DCMU) on the stop-response was also determined. With background light of different wavelength (614, 658 and 686 nm) the stop-response increased. DCMU inhibited this effect of background light. Negative results with the monoclonal antibody Pea-25 directed to phytochrome and the results with DCMU, indicate that the stop-response of G. dorsum is coupled to photosynthesis rather than to a phytochrome-like pigment. Oxygen evolution, but not cell movement, was completely inhibited by 10-6 M DCMU.

  • 4. Ferreira, Daniela
    et al.
    Leitão, Elsa
    Sjöholm, Johannes
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Oliveira, Paulo
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Lindblad, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Moradas-Ferreira, Pedro
    Tamagnini, Paula
    Transcription and regulation of the hydrogenase(s) accessory genes, hypFCDEAB, in the cyanobacterium Lyngbya majuscula CCAP 1446/42007In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 188, no 6, p. 609-617Article in journal (Refereed)
    Abstract [en]

    Lyngbya majuscula CCAP 1446/4 is a filamentous cyanobacterium possessing both an uptake and a bi-directional hydrogenase. The presence of a single copy of the hyp operon in the cyanobacterial genomes suggests that these accessory genes might be responsible for the maturation of both hydrogenases. We investigated the concomitant transcription of hypFCDEAB with the hydrogenases structural genes-hup and hox. RT-PCRs performed with L. majuscula cells grown under different physiological conditions showed a substantial decrease in the relative amount of hupL transcript under non-N-2-fixing conditions. In contrast, no significant differences were observed for the transcript levels of hypFCDEAB in all conditions tested, while minor fluctuations could be discerned for hoxH. Previously, it was demonstrated that the transcriptional regulators NtcA and LexA interact with the promoter regions of hup and hox, respectively, and that putative binding sites for both proteins are present in the hyp promoter of L. majuscula. Therefore, a putative involvement of NtcA and LexA in the regulation of the hyp transcription was investigated. Electrophoretic mobility shift assays resulted in NtcA or LexA-bound retarded fragments, suggesting the involvement of these proteins in the transcriptional regulation of hypFCDEAB.

  • 5. Hagemann, Martin
    et al.
    Hasse, Dirk
    University of Rostock, Germany.
    Berg, Gabriele
    Detection of a phage genome carrying a zonula occludens like toxin gene (zot) in clinical isolates of Stenotrophomonas maltophilia.2006In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 185, no 6Article in journal (Refereed)
    Abstract [en]

    During a study of the genetic diversity of Stenotrophomonas strains, we found an autonomous replicating DNA molecule in chromosomal DNA preparations of the clinical Stenotrophomonas maltophilia strain c5. The entire sequence of 6,907 bp of the isolated DNA molecule was determined, which was called phiSMA9. Seven ORFs, which code for proteins with considerable similarity to proteins in databases, were identified in the DNA sequence. The largest ORF shows high sequence similarities to the pI protein of the filamentous phage phiLf, which was later shown to be identical to toxin Zot of Vibrio cholerae. Beside the Zot-like protein, six other proteins with similarities to known phage proteins such as a phage replication protein RstA and phage absorption or coat protein are encoded on phiSMA9, which indicate that this circular DNA molecule represents the replicative form of a linear phage genome. A PCR-based screening showed that only five from the totally investigated 47 Stenotrophomonas strains of clinical and environmental origin harbor these genes. Altogether, we describe the first genome of a phage for the nosocomial pathogen Stenotrophomonas, which contains a Zot toxin like gene and might be regarded as the first Stenotrophomonas virulence factor.

  • 6.
    Karlsson, Anna
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Bo
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    CO2-dependent fermentation of phenol to acetate, butyrate and benzoate by an anaerobic, pasteurised culture2000In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 173, no 5-6, p. 398-402Article in journal (Refereed)
    Abstract [en]

    Fermentative degradation of phenol was studied using a non-methanogenic, pasteurised enrichment culture containing two morphologically different bacteria. Phenol was fermented to benzoate, acetate and butyrate and their relative occurrence depended on the concentration of hydrogen. Proportionately more benzoate was formed with high initial levels of H2. The influence of P(H2) on the fermentation pattern was studied both in dense cell suspensions and in growing cultures by addition of hydrogen. An increase in growth yield (OD578 was observed, compared to controls, as a consequence of phenol degradation, however, the increase was less in H2-amended treatments, in which most of the phenol ended up as benzoate. The degradation of phenol in the dense cell suspension experiments was dependent on CO2. Benzoate was not degraded when added as a substrate to the growing culture. This is, to our knowledge, the first report concerning the fermentative degradation of phenol to nonaromatic products.

  • 7. Leganés, Francisco
    et al.
    Blanco-Rivero, Amaya
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid.
    Fernández-Piñas, Francisca
    Redondo, Miguel
    Fernández-Valiente, Eduardo
    Fan, Qing
    Lechno-Yossef, Sigal
    Wolk, C Peter
    Wide variation in the cyanobacterial complement of presumptive penicillin-binding proteins2005In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 184, no 4, p. 234-248Article in journal (Refereed)
    Abstract [en]

    A genomic analysis of putative penicillin-binding proteins (PBPs) that are involved in the synthesis of the peptidoglycan layer of the cell wall and are encoded in 12 cyanobacterial genomes was performed in order to help elucidate the role(s) of these proteins in peptidoglycan synthesis, especially during cyanobacterial cellular differentiation. The analysis suggested that the minimum set of PBPs needed to assemble the peptidoglycan layer in cyanobacteria probably does not exceed one bifunctional transpeptidase-transglycosylase Class A high-molecular-weight PBP; two Class B high-molecular-weight PBPs, one of them probably involved in cellular elongation and the other in septum formation; and one low-molecular-weight PBP. The low-molecular-weight PBPs of all of the cyanobacteria analyzed are putative endopeptidases and are encoded by fewer genes than in Escherichia coli. We show that in Anabaena sp. strain PCC 7120, predicted proteins All2981 and Alr4579, like Alr5101, are Class A high-molecular-weight PBPs that are required for the functional differentiation of aerobically diazotrophic heterocysts, indicating that some members of this class of PBPs are required specifically for cellular developmental processes.

  • 8. Lin, Po-Chi
    et al.
    Puhar, Andrea
    Biochemisches Institut, Universität Zürich, Zurich, Switzerland, Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, Paris Cedex 15, France.
    Steuber, Julia
    NADH oxidation drives respiratory Na+ transport in mitochondria from Yarrowia lipolytica2008In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 190, no 4, p. 471-480Article in journal (Refereed)
    Abstract [en]

    It is generally assumed that respiratory complexes exclusively use protons to energize the inner mitochondrial membrane. Here we show that oxidation of NADH by submitochondrial particles (SMPs) from the yeast Yarrowia lipolytica is coupled to protonophore-resistant Na+ uptake, indicating that a redox-driven, primary Na+ pump is operative in the inner mitochondrial membrane. By purification and reconstitution into proteoliposomes, a respiratory NADH dehydrogenase was identified which coupled NADH-dependent reduction of ubiquinone (1.4 micromol min(-1) mg(-1)) to Na+ translocation (2.0 micromol min(-1) mg(-1)). NADH-driven Na+ transport was sensitive towards rotenone, a specific inhibitor of complex I. We conclude that mitochondria from Y. lipolytica contain a NADH-driven Na+ pump and propose that it represents the complex I of the respiratory chain. Our study indicates that energy conversion by mitochondria does not exclusively rely on the proton motive force but may benefit from the electrochemical Na+ gradient established by complex I.

  • 9. Neubauer, H
    et al.
    Pantel, I
    Lindgren, Per-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Characterization of the molybdate transport system ModABC of Staphylococcus carnosus. 1999In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 172, p. 109-115Article in journal (Refereed)
  • 10.
    Selstam, Eva
    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).
    Campbell, D
    Membrane lipid composition of the unusual cyanobacterium Gloeobacter violaceus sp PCC 7421, which lacks sulfoquinovosyl diacylglycerol1996In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 166, no 2, p. 132-135Article in journal (Refereed)
    Abstract [en]

    Gloeobacter violaceus sp. PCC 7421 is an unusual cyanobacterium with only one cellular membrane, which lacks the thylakoid membranes found in other oxygenic photosynthetic organisms. The cell membrane lipids in G. violaceus sp. PCC 7421 are monogalactosyl diacylglycerol, digalactosyl diacylglycerol, phosphatidyl glycerol and phosphatidic acid in the molar proportion of 51, 24, 18 and 4% respectively. This lipid composition resembles that of the cell membrane from other cyanobacteria, but completely lacks sulfoquinovosyl diacylglycerol. This lack of sulfoquinovosyl diacylglycerol is exceptional for a photosynthetic membrane. The membrane lipids are esterified to 14:0, 16:0, 16:1, 18:0, 18:1, 18:2 and alpha 18:3 fatty acids.

  • 11. Sirijovski, Nick
    et al.
    Mamedov, Fikret
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Olsson, Ulf
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Hansson, Mats
    Rhodobacter capsulatus magnesium chelatase subunit BchH contains an oxygen sensitive iron-sulfur cluster2007In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 188, no 6, p. 599-608Article in journal (Refereed)
    Abstract [en]

    Magnesium chelatase is the first unique enzyme of the bacteriochlorophyll biosynthetic pathway. It consists of three subunits (BchI, BchD, and BchH). Amino acid sequence analysis of the Rhodobacter capsulatus BchH revealed a novel cysteine motif ((393)CX(2)CX(3)CX(14)C) that was found in only six other proteobacteria (CX(2)CX(3)CX(11-14)C). The cysteine motif is likely to coordinate an unprecedented [Fe-S] cluster. Purified BchH demonstrated absorbance in the 460 nm region. This absorbance was abolished in BchH proteins with alanine substitutions at positions Cys396 and Cys414. These modified proteins were also EPR silent. In contrast, wild type BchH protein in the reduced state showed EPR signals resembling those of a [4Fe-4S] cluster with rhombic symmetry and g values at 1.90, 1.93, and 2.09, superimposed with a [3Fe-4S] cluster centered at g = 2.02. The [3Fe-4S] signal was observed independently of the [4Fe-4S] signal under oxidizing conditions. Mg-chelatase activity assays showed that the cluster is not catalytic. We suggest that the [4Fe-4S] and [3Fe-4S] signals originate from a single coordination site on the monomeric BchH protein and that the [4Fe-4S] cluster is sensitive to oxidation. It is speculated that the cluster participates in the switching between aerobic and anaerobic life of the proteobacteria.

  • 12.
    Strandberg, Rebecka
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Tzelepis, Georgios
    Johannesson, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Karlsson, Magnus
    Coexistence and expression profiles of two alternative splice variants of the pheromone receptor gene pre-1 in Neurospora crassa2013In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 195, no 10-11, p. 773-780Article in journal (Refereed)
    Abstract [en]

    In this study, we show that two splice variants of the pheromone receptor gene (pre-1) transcript coexist in vegetative and reproductive tissues of the filamentous ascomycete fungus Neurospora crassa. The two splice variants differ by intron retention of the last intron, which is predicted to result in a premature stop codon and loss of 322 amino acids in the C-terminal cytosolic region of PRE-1. Using quantitative PCR, we show that expression of the variants is influenced by mating type (mat), with a higher proportion of intron-spliced transcripts in a mat A strain and a higher proportion of the intron-retained variant in a mat a strain. The intron-retained PRE-1 variant is predicted to lack 6 ubiquitination sites that may influence receptor function. In conclusion, N. crassa produce two pre-1 splice variants that display different transcription profiles.

  • 13. Wegrzyn, A.
    et al.
    Czyz, A.
    Gabig-Ciminska, Magdalena
    KTH, Superseded Departments, Biotechnology.
    Wegrzyn, G.
    ClpP/ClpX-mediated degradation of the bacteriophage lambda O protein and regulation of lambda phage and lambda plasmid replication2000In: Archives of Microbiology, ISSN 0302-8933, E-ISSN 1432-072X, Vol. 174, no 02-jan, p. 89-96Article in journal (Refereed)
    Abstract [en]

    The O protein is a replication initiator that binds to the ori lambda region and promotes assembly of the bacteriophage lambda replication complex. This protein, although protected from proteases by other elements of the replication complex, in a free form is rapidly degraded in the host, Escherichia coil, by the ClpP/ClpX protease. Nevertheless, the physiological role of this rapid degradation remains unclear. Here we demonstrate that the copy number of plasmids derived from bacteriophage lambda is significantly higher in wild-type cells growing in rich media than in slowly growing bacteria. However, lambda plasmid copy number in bacteria devoid of the ClpP/ClpX protease was not dependent on the bacterial growth rate and in all minimal media rested was comparable to that observed in wildtype cells growing in a rich medium. Contrary to lambda plasmid replication, the efficiency of lytic growth of bacteriophage lambda was found to be dependent on the host growth rate in both wild-type bacteria and clpP and clpX mutants. The activities of two major lambda promoters operating during the lytic development, p(R) and p(L), were found to be slightly dependent on the host growth rate. However, when p(R) activity was significantly decreased in the dnaA mutant, production of phage progeny was completely abolished at low growth rates. These results indicate that the O protein (whose level in E. coli cells depends on the activity of ClpP/ClpX protease) is a major limiting factor in the regulation of lambda plasmid replication at low bacterial growth rates. However, this protein seems to be only one of the limiting factors in the bacteriophage lambda lytic development under poor growth conditions of host cells. Therefore, it seems that the role of the rapid ClpP/ClpX-mediated proteolysis of the O protein is to decrease the efficiency of early DNA replication of the phage in slowly growing host cells.

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