Capacity for hexose respiration in symbiotic <i>Frankia</i> from <i>Alnus incana</i>

Vikman, Per‐Åke; Huss‐Danell, Kerstin

doi:10.1111/j.1399-3054.1987.tb06154.x

Cited by 12 publications

(5 citation statements)

References 26 publications

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“…The sugars sucrose, trehalose, maltose, glucose and fructose stimulated respiration in vesicle clusters from Alnus rubra (Lopez, Young & Torrey, 19866). Respiration in vesicle clusters of Alnus incana was stimulated by glucose and the phosphorylated sugars glucose-6-phosphate and 6-phosphogluconate in the presence of NAD (Vikman & Huss-Danell, 1987«). Several relevant enzymes (hexokinase, glucose-6phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and pyruvate kinase) were active in vesicle clusters from the nodules of these two species of alder (Lopez & Torrey, 1985;Vikman & Huss-Danell, 1987a).…”

Section: Carbon Metabolism In Nodulesmentioning

confidence: 98%

Actinorhizal symbioses and their N₂ fixation

1997

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summary More than 200 angiosperms, distributed in 25 genera, develop root nodule symbioses (actinorhizas) with soil bacteria of the actinomycetous genus Frankia. Although most soils studied contain infective Frankia, cultured strains are available only after isolation from root nodules. Frankia infects roots via root hairs in some hosts or via intercellular penetration in others. The nodule originates in the pericycle. The number of nodules in Alnus is determined by the plant in an autoregulated process that, in turn, is modulated by nutrients such as nitrogen and phosphate. Except in the genera Allocausarina and Casuarina, Frankia in nodules develops so‐called vesicles where nitrogenase is localized. Sporulation of Frankia occurs in some symbioses. As a group, actinorhizal plants show a large range of anatomical and biochemical adaptations in order to balance the oxygen tension near nitrogenase. In symbioses with well aerated nodule tissue like Alnus, the vesicles have a multilayered envelope composed mainly of lipids, bacterio‐hopanetetrol and their derivatives. This envelope is assumed to retard the diffusion of oxygen into the nitrogenase‐containing vesicle. In symbioses like Casuarina, the infected plant cells themselves, rather than Frankia, appear to retard oxygen diffusion, and high concentrations of haemoglobin indicate an infected region with a low oxygen tension. At least in Alnus spp., ammonia resulting from N2 fixation is assimilated by glutamine synthetase in the plant. The carbon compound(s) used by Frankia in nodules is not yet known. Nitrogenase activity decreases in response to a number of environmental factors but recovers upon return to normal conditions. This dynamism in nitrogenase activity is often explained by loss and recovery of active nitrogenase and has been traced to loss and recovery of the nitrogenase proteins themselves. Recovery is partly due to growth of Frankia and to development of new vesicles in the Alnus nodules. In the field, varying conditions continuously affect the plants and the measured rate of N2 fixation is a result not only of the conditions prevailing at the moment but also of the conditions experienced over preceding days. N2 fixed by actinorhizal plants is substantial and actinorhizal plants have great potential in soil reclamation and in various types of forestry. Several species are also useful in horticulture.

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Section: Carbon Metabolism In Nodulesmentioning

confidence: 98%

Actinorhizal symbioses and their N₂ fixation

1997

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“…have not been isolated yet, so their carbon source preferences have yet to be analyzed. Studies on the metabolism of symbiotic Frankia have been performed using so-called vesicle clusters, consisting of symbiotic vesicles together with a part of their subtending hyphae isolated from nodules (Van Straten et al, 1977;Vikman and Huss-Danell, 1987b). Vesicle clusters from Alnus spp.…”

Section: Supplying the Microsymbiont With Energymentioning

confidence: 99%

Root-based N2-fixing Symbioses: Legumes, Actinorhizal Plants, Parasponia sp. and Cycads

2005

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In the mutualistic symbioses between legumes and rhizobia, actinorhizal plants and Frankia, Parasponia sp. and rhizobia, and cycads and cyanobacteria, the N 2 -fixing microsymbionts exist in specialized structures (nodules or cyanobacterial zones) within the roots of their host plants. Despite the phylogenetic diversity among both the hosts and the microsymbionts of these symbioses, certain developmental and physiological imperatives must be met for successful mutualisms. In this review, phylogenetic and ecological aspects of the four symbioses are first addressed, and then the symbioses are contrasted and compared in regard to infection and symbio-organ development, supply of carbon to the microsymbionts, regulation of O 2 flux to the microsymbionts, and transfer of fixed-N to the hosts. Although similarities exist in the genetics, development, and functioning of the symbioses, it is evident that there is great diversity in many aspects of these root-based N 2 -fixing symbioses. Each symbiosis can be admired for the elegant means by which the host plant and microsymbiont integrate to form the mutualistic relationships so important to the functioning of the biosphere.

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“…The very low ratio (0,4%) of mitochondrial volume to total volume of material in the preparations (Tab, 2) implies that mitochondrial contamination was negligible. We have shown previously that activity of soluble cytoplasmic host enzymes was undetectable in veside cluster preparations and that Frankia membrane integrity was at least partly retained (Vikman and Huss-Danell 1987), These facts all imply that this kind of preparation is suitable for studies on the metabolism of symbiotic Frankia from Alnus incana root nodules.…”

Section: Pktare Analysismentioning

confidence: 78%

“…Respiration of vesicle clusters expressed on total protein basis was 60 nmol O^ (mg prot) ' min"' (Vikman and Huss-Daneil 1987). This rate corresponds to tiie rates below if the following assumptions are made: 1) the relative volumes of different structures in a vesicle cluster are as found in Tab, 2; 2) respiration is performed only by the specified fraction; 3) the protein concentration is similar in ail structures in a vesicie duster, a. Douce (1985), NADH as substrate of 60 nmol O2 (mg protein) ' min ' (Vikman and Huss-Danell 1987), Assuming that protein is equally distributed between the different structures in the preparation, and that respiration was only performed by mitochondria (Tab, 3), then these mitochondria would have a respiration rate that is about 30 times higher than obtained in the best mitochondrial preparations (Douce 1985), Even if all the observed non-Frankia material (mitochondria and miscellaneous) were able to respire, which is very unlikely, this means that they would have to be 7 times as active as the best preparations of mitochondria from yeast (Douce 1985), Such high respiratory rates are very unlikely. The assumption on equal protein distribution (Tab.…”

Section: Pktare Analysismentioning

confidence: 96%

Purity of Frankia preparations from root nodules of Alnus incana

Vikman¹,

Huss‐Danell²

1987

Physiologia Plantarum

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K. 1987, Purity of Frankia preparations from root noduies of Ainus incana. -Physiol. Piant, 71: 489-494.Frankia vesicle clusters were prepared from Alnus incana (L.) Moench root nodules by a homogenization-filtration procedure. The preparation was examined by transmission electron microscopy and computerized picture analysis to quantify contamination from tbe host plant. Spedai attention was paid to piant mitochondria. Mitochondria were only found in 30% of the 50 sections of clusters examined. In sections containing mitochondria the mean number of mitochondria per cluster section was 1.5, The relative volume of all objects found in the vesicle clusters was calculated. More than 98% of the volume of a preparation consisted of Frankia vesicles and hyphae, while only 0,4% of the volume was host plant mitochondria. The frequency of mitochondria in a preparation could be birther decreased by osmotic shock. It is conduded that Frankia veside clusters, prepared from Alnus incana by the homogenization-filtration technique used here, are suffidently pure to be used for studies of Frankia metabolism.

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Capacity for hexose respiration in symbiotic Frankia from Alnus incana

Cited by 12 publications

References 26 publications

Actinorhizal symbioses and their N₂ fixation

Actinorhizal symbioses and their N₂ fixation

Root-based N2-fixing Symbioses: Legumes, Actinorhizal Plants, Parasponia sp. and Cycads

Purity of Frankia preparations from root nodules of Alnus incana

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Capacity for hexose respiration in symbiotic Frankia from Alnus incana

Cited by 12 publications

References 26 publications

Actinorhizal symbioses and their N2 fixation

Actinorhizal symbioses and their N2 fixation

Root-based N2-fixing Symbioses: Legumes, Actinorhizal Plants, Parasponia sp. and Cycads

Purity of Frankia preparations from root nodules of Alnus incana

Contact Info

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Actinorhizal symbioses and their N₂ fixation

Actinorhizal symbioses and their N₂ fixation