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Sökning: swepub > Umeå universitet > Tidskriftsartikel > (1990-1994) > Sellstedt Anita 1955

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1.
  • Sellstedt, Anita, 1955-, et al. (författare)
  • IDENTIFICATION OF CASUARINA-FRANKIA STRAINS BY USE OF POLYMERASE CHAIN-REACTION (PCR) WITH ARBITRARY PRIMERS
  • 1992
  • Ingår i: FEMS Microbiology Letters. - 0378-1097. ; 93:1, s. 1-5
  • Tidskriftsartikel (refereegranskat)abstract
    • 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.
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2.
  • LINDBLAD, P, et al. (författare)
  • OCCURRENCE AND LOCALIZATION OF AN UPTAKE HYDROGENASE IN THE FILAMENTOUS HETEROCYSTOUS CYANOBACTERIUM NOSTOC PCC-73102
  • 1990
  • Ingår i: Protoplasma. - 0033-183X. ; 159:1, s. 9-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Free-living nitrogen-fixing Nostoc PCC 73102, a filamentous heterocystous cyanobacterium originally isolated from coralloid roots of the cycad Macrozamia sp., were examined for the presence of an uptake hydrogenase (H-2ase) enzyme. In vivo and in vitro hydrogen uptake measurements were used to study activities and SDS-PAGE and Western immunoblots to reveal occurrence of the hydrogenase protein. Also, transmission electron microscopy and immunocytological labeling were used to study the cellular and subcellular distribution of H-2se in the Nostoc cells. In vivo measurements demonstrated an active uptake of hydrogen in both light and darkness. Light stimulated in vivo hydrogen uptake with approximately 100%, and this was further doubled by increasing the pH2, from 56 to 208-mu-M H-2. An in vitro hydrogen of 1.1-mu-mol H-2/mg (protein)/h was observed when using phenazinemethosulphate as e- -acceptor. Western immunoblots revealed that a polypeptide with a molecular weight of about 55 kDa was immunologically related to uptake H-2ase holoenzyme purified from Alcaligenes latus. Immunolocalization demonstrated that the H-2ase protein was located both in heterocysts and vegetative cells. A higher specific labeling was associated with the cytoplasmic membranes where the vegetative cells are in contact with each other and where they actually are dividing into two vegetative cells. Using the particle analysis of an image processor, approximately equal H-2ase-gold labeling per cell area was observed in the nitrogen-fixing heterocysts compared to the photosynthetic vegetative cells. This study also shows that there was no correlation between presence of phycoerythrin and uptake H-2ase activity.
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5.
  • Sellstedt, Anita, 1955-, et al. (författare)
  • COMPOSITION OF AMINO-COMPOUNDS TRANSPORTED IN XYLEM OF CASUARINA SP
  • 1991
  • Ingår i: Journal of Experimental Botany. - 0022-0957. ; 42:245, s. 1493-1497
  • Tidskriftsartikel (refereegranskat)abstract
    • Seedlings (180-d-old) of Casuarina cunninghamiana L., C. equisetifolia Miq. and C. glauca Sieber inoculated with each of two different sources of Frankia, were analysed for translocated nitrogenous compounds in xylem sap. Analyses were also made on sap from nodulated and non-nodulated plants of C. glauca grown with or without a range of levels of combined nitrogen. Xylem exudates were collected from stems, roots, and individual nodules of nodulated plants and from stems and roots of non-nodulated plants. While the proportional composition of solutes varied, the same range of amino compounds was found in xylem sap from the three different symbioses. In C. glauca asparagine was the major amino acid in the root sap followed by proline, while in symbiotic C. cunninghamiana arginine accounted for more than 25% of the amino compounds. Citrulline was the major translocated product found in the stem exudate of symbiotic C. equisetifolia. Increasing concentrations of ammonium nitrate in the nutrient solution resulted in increasing levels of free ammonia and glutamine in xylem sap from stems of nodulated and non-nodulated C. glauca, but there was relatively little change in the prominent solutes, e.g. citrulline, proline, and arginine. The composition of nitrogenous solutes in stem or root exudates of C. glauca was similar to that of exudate collected from individual nodules and on this basis it was not possible to distinguish specific products of current N2 fixation in xylem. The main differences in N solute composition between the symbioses were apparently due to host plant effects rather than nodulation or the levels of combined N. Also, the data indicate that the use of the proportion of N in sap as citrulline (or indeed any other orgnaic N solute) could not be used as an index of nitrogen fixation.
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6.
  • Sellstedt, Anita, 1955-, et al. (författare)
  • EFFECT OF CARBON SOURCE ON GROWTH, NITROGENASE AND UPTAKE HYDROGENASE ACTIVITIES OF FRANKIA ISOLATES FROM CASUARINA SP
  • 1994
  • Ingår i: Plant and Soil. - 0032-079X. ; 158:1, s. 63-68
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of different carbon sources on the growth of Frankia isolates for Casuarina sp. was studied. In addition, regulation of nitrogenase and uptake hydrogenase activity by carbon sources was investigated. For each of the three isolates, JCT287, KB5 and HFPCcI3, growth was greatest on the carbon sources pyruvate and propionate. In general the carbon sources which gave the greatest growth gave the highest levels of nitrogenase activity, but repressed the activity of uptake hydrogenase. The regulation of growth, uptake hydrogenase activity and nitrogenase activity is discussed.
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7.
  • Sellstedt, Anita, 1955-, et al. (författare)
  • THE OCCURRENCE OF HEMOGLOBIN AND HYDROGENASE IN NODULES OF 12 CASUARINA-FRANKIA SYMBIOTIC ASSOCIATIONS
  • 1991
  • Ingår i: Physiologia Plantarum : An International Journal for Plant Biology. - 0031-9317. ; 82:3, s. 458-464
  • Tidskriftsartikel (refereegranskat)abstract
    • Seedlings of Casuarina cunninghamiana Miq., C. equisetifolia L. and C. glauca Sieber growing in N-deficient potting mix were inoculated with Frankia sp. from each of 4 different sources. After ca 4 months, plants were harvested and nodules from the 12 Casuarina-Frankia combinations evaluated for (1) concentrations of haemoglobin (measured as CO-reactive haem) and (2) occurrence of hydrogenase. The aim was to determine if these factors were related to nitrogen accumulation and biomass production. There were marked host-Frankia source interactions with up to 10-fold differences in plant dry weight and 50-fold differences in the efficiency of nitrogen fixation (as estimated by N2 accumulated mg-1 nodule dry weight). Differences in plant growth and nitrogen accumulation were apparently related to nodule specific activity, because the 12 associations had similar nodulation characteristics, e.g. for time for nodulation to occur. The concentration of haemoglobin in Casuarina nodules ranged from 0 to 27 nmol haem (g FW)-1. There was a strong linear correlation between concentrations of haemoglobin and dry weights of the whole plants (r = 0.77, 0.92 and 0.97, P less-than-or-equal-to 0.05) for C. cunninghamiana, C. equisetifolia and C. glauca symbiotic associations, respectively. However, the linear correlation between concentration of haemoglobin and nitrogen content of whole plant was lower (r = 0.60, 0.64 and 0.71, P less-than-or-equal-to 0.05) for the three Casuarina symbioses, respectively, and there was only a poor correlation between haemoglobin concentration in nodules and the rate of nitrogen accumulation on nodule weight basis. This indicates that haemoglobin concentration is not the sole physiological determinant of nitrogen fixation in Casuarina. All the Casuarina-Frankia symbiotic associations studied also showed the presence of a hydrogen uptake enzyme. The activity of the enzyme ranged from 5.1 to 34.1-mu-mol H2 (g FW)-1 h-1, and hydrogen uptake was not correlated with plant dry weight, nitrogen content or the rate of nitrogen fixation. Hydrogen evolution could not be detected in any of the associations.
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