Showing papers on "Frankia published in 1983"

An effective strain of Frankia from Casuarina sp.

Abstract: A strain of Frankia, designated Cj1-82, from root nodules of a hybrid of Casuarina junghuhniana and C. equisetifolia has been isolated in pure culture. When grown under standard culture conditions, Cj1-82 exhibited the following characteristics: cushionlike colonies with short, wide hyphae and, in addition to typical sporangia, intercalary elongated sporangialike structures (SLS) which could be disrupted into sporelike units. No vesicles were found. When inoculated into the rhizosphere of C. equisetifolia, Cj1-82 produced vesicles. Reinfection of seedlings of C. equisetifolia was achieved repeatedly with inocula prepared from a suspension of Cj1-82. Sequences of infection of root hairs were described. Fourteen days after inoculation, nodules were apparent on the roots. Nodules were shown to be effective in nitrogen fixation as assessed by the acetylene-reduction technique.

Frankia diversity in an alder stand as estimated by sodium dodecyl sulfate - polyacrylamide gel electrophoresis of whole-cell proteins

Abstract: Procedures for estimating the diversity of Frankia isolates are described. Forty-three alder isolates were separated into six groups by comparing protein patterns obtained during sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE) of whole-cell lysates. Thirty-five of the strains comprised group A and were indistinguishable from one another. Four strains were quite similar to a Comptonia peregrina isolate (CpI1) and were included in group C. Group D had two members and groups B, E, and F each had one member. The groupings were confirmed by hyphal morphology, colony appearance, and carbon source utilization patterns.

The isolation of Frankia from nodules of Casuarina

Abstract: Attempting to isolate Frankia from Casuarina, we found that this endophyte exhibited two unexpected characteristics: (i) an inability of most infected nodule cells to produce Frankia colonies; and ...

Studies of growth and morphology of Frankia strains EAN1pec, EuI1c, CpI1, and ACN1AG

Abstract: A study was made of the ability of four strains of Frankia, representing two distinct host-compatibility groups, to utilize various carbon sources for growth. Isolates EAN1pec and EuI1c, representa...

Physiology, chemistry, serology, and infectivity of two Frankia isolates from Alnus incana subsp. rugosa

Abstract: Actinorhizal nodules of Alnus incana ssp. rugosa collected from plants growing within 30 km of each other in Jeffersonville and Stowe, VT, U.S.A., yielded two morphologically distinct strains of Frankia. A comparison of the cell chemistry of the strains showed that each had the same type of cell wall and whole-cell sugar and phospholipid composition; however, AirI2 lacked the unknown amino acid found in the cells of all frankiae previously examined. Their cellular fatty acid composition showed only minor qualitative differences. Physiologically, the strains differed in their relation to oxygen, in their uptake and utilization of carbohydrates, organic acids, and lipids, and in protease production. AirI1 induced effective nodules in the host plant; those of AirI2 were ineffective. AirI2 was unrelated serologically to all frankiae previously isolated from the genus Alnus. AirI1 was serologically typical.

Root hair deformation in the infection process of Alnus rubra

Abstract: Structural and cell developmental studies of root hair deformation in Alnus rubra Bong. (Betulaceae) were carried out following inoculation with the soil pseudomonad Pseudomonas cepacia 85, alone or in concert with Frankia, and using axenically grown seedlings. Deformational changes can be observed in elongating root hairs within 2 h of inoculation with P. cepacia 85. These growing root hairs become branched or multilobed and highly modified from the single-tip growth of axenic root hairs. The cell walls of deformed hairs are histologically distinctive when stained with the fluorochrome acridine orange. Filtrate studies using P. cepacia 85 suggest that the deforming substance is not a low molecular weight compound. Root hair deformation and the associated wall histology are host specific in that Betula root hairs show none of these responses when grown and inoculated in the experimental conditions described. The bacterially induced changes in root hair cell walls during deformation may create a chemically...

2-O-Methyl-D-mannose, a key sugar in the taxonomy of Frankia

Abstract: The classification of actinomycetes in the genus Frankia Brunchorst has been based partly on morphology but primarily on their ability to form N2-fixing nodules on roots of actinorhizal host plants. To identify nonsporulating and noninfective Frankia isolates, biochemical tests are needed. Sugars present in whole-cell hydrolysates have proven useful in the taxonomy of other genera of actinomycetes. We, and others, have found a sugar in all Frankia isolates examined thus far that is absent in all other actinomycetes tested. After reduction with NaBD2H4 and acetylation, the characteristic sugar was found by gas chromatographic and mass spectrometric analyses to be a 2-O-methyl hexose. The sugar was partially purified by high pressure liquid chromatography and demethylated to give a major product of mannose. Authentic 2-O-methyl mannose as its alditol acetate and trimethylsilyl methyl glycoside derivatives cochromatographed with the sugar. By gas–liquid chromatography of its trimethylsilyl (−)-2-butyl glycos...

Host–endophyte interactions in effective and ineffective nodules induced by the endophyte of Myrica gale

Abstract: Suspensions of crushed root nodules of Myrica gale containing the actinomycete Frankia induced nodule formation on roots of seedlings of M. gale and Comptonia peregrina grown in nutrient water culture. Nodules formed on M. gale were normal in structure and exhibited nitrogenase activity (measured as acetylene reduction) and provided the necessary nitrogen for seedling development. These effective nodules showed typical external and internal structure with the endophyte developing both vesicles and sporangia within cortical cells of the host tissue. Small nodules formed on C. peregrina representing the primary nodule stage. They lacked nitrogenase activity and were termed ineffective. Vesicles failed to develop within these ineffective nodules. However, sporangia were formed in infected cells and within intercellular spaces of the nodule cortical tissue. In addition, prominent amyloplasts occurred in infected cells of the ineffective nodules, a feature lacking in effective nodules. Exogenously supplied com...

Studies on the growth of Frankia isolates in relation to infectivity and nitrogen fixation (acetylene reduction)

Abstract: Several Frankia isolates were tested for their growth ability on a mineral medium containing glucose, succinic acid, or propionic acid as the sole carbon–energy source. Utilization of these nutrien...

Utilization of carbon and nitrogen compounds by Frankia in synthetic media and in root nodules of Alnus glutinosa, Hippophae rhamnoides and Datisca cannabina

Abstract: Frankia AvcI1 utilizes only Tweens and fatty acids as sole carbon sources but N2, NH4+, NO3−, and various amino acids as nitrogen sources. The yield in propionate medium was increased by CO2. Cells grown in media with Tween 80 or acetate as C source contain the glyoxylate-cycle enzymes, isocitrate lyase and malate synthase. These enzymes are repressed in cells grown in media with propionate as well as in the symbiotic stage of Frankia in the nodules. The nature of the carbon compounds utilized by Frankia in the nodule symbiosis is discussed. Vesicle clusters derived from root nodules of Alnus respire succinate (however, only at a very low rate, which probably is due to damage of the membrane of the endophyte). Vesicle clusters derived from Alnus and Hippophae nodules also take up O2 when supplied with a mixture of glutamate, malate, and NAD, indicating that the reduction equivalents could be transported from the host to the endophyte via the malate–aspartate shuttle. Vesicle clusters derived from Datisca ...

Cataloging Frankia strains

Abstract: A catalog listing known Frankia isolates and introducing a homogeneous numbering system for all strains will be published and distributed to interested scientists. Details are given concerning the procedure to be followed for cataloging the strains as well as the coding of information about them. An up-to-date listing of actinorhizal plant species is included along with the codes to be used for each plant taxon.

Effects of Pseudomonas cepacia and cultural factors on the nodulation of Alnus rubra roots by Frankia

Abstract: Infection of Alnus rubra Bong, roots by Frankia isolates was consistently promoted by Pseudomonas cepacia "helper" bacteria under a variety of cultural conditions. Pseudomonas cepacia, while helpful, was never necessary in securing nodulation of aseptic A. rubra by Frankia. Live P. cepacia cells were added with a Frankia isolate to aseptically grown A. rubra seedlings on Hoagland's agar slants. This doubled, on average, the number of nodules formed by Frankia alone when Frankia isolate, age of Frankia inoculum, Frankia medium, calcium concentration of seedling substrate, phosphate concentration of seedling substrate, and pH of seedling substrate were varied. There was an apparent interaction between seedling substrate pH and P. cepacia in the promotion of nodulation. At pH levels from 4.0 to 6.0 the infectivity of Frankia isolate ArI3 alone was greatly depressed compared with infectivity at the optimal pH for the growth of ArI3, around 7.0. However, at pH levels of 5.0, 5.5, and 6.0 the ability of P. cepa...

Influence of phenolics on in vitro growth of Frankia strains

Abstract: The influence of some common plant phenolics was tested on six Frankia strains isolated from both Alnus and Elaeagnus host plants. The addition of 1 mM of different phenolics to QmodB broth significantly influenced the growth and (or) the morphological development of Frankia. Ferulic, o-coumaric, and p-coumaric acids were extremely effective in inhibiting the growth of Frankia colonies, increasing the ramification of hyphae, and decreasing the number and size of sporangia produced in vitro. However, benzoic and p-hydroxybenzoic acids did not influence the total growth of Frankia colonies but stimulated the in vitro production of spherical septate vesicles on the two strains of Frankia type N tested. The possibility that these active phenolics, which are known to be present in Alnus actinorhizae, might act as "chemical mediators" between the host cell and its endophytic Frankia is suggested.

Deoxyribonucleic acid base composition of 12 Frankia isolates

Abstract: The base compositions of the DNA from 12 Frankia isolates were determined. The guanine plus cytosine content fell within the range of 68.4–72.1 mol% for all of the isolates tested. The DNA's from one Alnus isolate, one Comptonia isolate, and two Elaeagnus isolates were analyzed for the occurrence of modified bases, and none were found.

Aspects of the cultural behaviour of Frankia and possible ecological implications

Abstract: Frankia isolates primarily from Casuarina, Hippophae, and Myrica were examined for their response to changes in temperature, pH, and water potential and for utilization of various substrates. Isolates differed in their responses. The general trends were that optimum growth was around 30 °C, the upper limits close to 40 °C, and the lower limits near 15 °C. Growth was generally favoured by pH values lying between 6 and 8 with the Casuarina isolate showing a narrower range. The general pattern of behaviour towards water potential was that growth declined below about −2 to −6 bar (1 bar = 100 kPa). Meagre growth was shown at −23 bar for isolates, except the one from Myrica which ceased to grow at potentials lower than about −18 bar. Isolates differed in ability to utilize monosaccharides and polysaccharides and tricarboxylic acids, but all utilized some volatile fatty acids. They also differed in ability to grow in the presence of inorganic and organic nitrogen sources, amino acids, and urea. Vitamins stimula...

The role of diffusion in oxygen protection of nitrogenase in nodules of Alnus rubra

Abstract: Endophyte respiration in actinorhizal nodules has two main functions: to provide ATP and reductant for nitrogenase and associated enzymes and to protect nitrogenase from inactivation by oxygen. Combined with a diffusion path which limits the flow of oxygen, the consumption of oxygen by respiration maintains a very low internal . We have used a continuous-flow root-nodule gas-exchange system to investigate the properties of such a diffusion path in intact, attached nodules of Alnus rubra infected with Frankia strain ArI3. When nodules were exposed to gas mixtures containing argon, oxygen, and acetylene, the resulting curves of ethylene production versus acetylene concentration showed diffusion-limited enzyme kinetics. Consequently, ethylene production at very low acetylene concentrations (<0.2% v/v) was used to characterize the diffusion path that both acetylene and oxygen must traverse to reach their active sites in the endophyte. The permeability of this path changed markedly with temperature and can acc...

Lectin binding on surfaces of Frankia strains

Abstract: As a prerequisite for the formation of symbiotic association the two partners must come in contact at their cell surfaces, where the phenomena of specificity and recognition are believed to take place. Therefore, in the case of actinorhizal symbioses, probing of Frankia cell surfaces was investigated with fluorescein-labelled lectins as specific markers for sugar residues. Eleven Frankia isolates grown in vitro and originating from Alnus and Elaeagnus host-plant specificity groups were tested with lectins of different carbohydrate-binding specificities. The N-acetylglucosamine and sialic acid binding lectin groups were able to bind to cell surfaces of both type-N and type-P strains of the Alnus group but not to any Frankia strains of the Elaeagnus group. Sugar residues recognized by these lectin groups on colonies of Frankia strains of the Alnus group were detected on hyphae, vesicles, and sporangia but not on mature spores. The present lectin binding study demonstrates that the use of lectins as bioprobe...

Studies on the localization of infectible cells on Alnus glutinosa roots

Abstract: Four Frankia isolates ofAlnus glutinosa were studied in relation to the location of infectible cells along 10 day oldAlnus glutinosa roots. For all isolates tested a clear zonation in infectible cells was found just above the position of the root tip at the time of infection. Differences in the length of the root nodule induction zone were observed, depending on the isolate and possibly also depending on the age of the Frankia culture tested. A second infection zone was found which was the only infectible zone by an isolate with a retarded infective potential (LDAgp1). Root hair deformation is clearly correlated with the presence of Frankia near axenic alder plants, although actual contact of root hairs and the symbiont is not prerequisite. Some evidence is presented indicating that the type of deformation might be correlated with the Frankia strain.

The polar lipids and free sugars of Frankia in culture

Abstract: To further the identification of characteristics common to Frankia strains, the phospholipids and sugars which are readily extracted with chloroform–methanol from whole cells were examined using nine strains of Frankia. Separation of extract components was achieved by thin-layer chromatography. In agreement with previous reports we have identified two phospholipids, phosphatidyl inositol and diphosphatidyl glycerol, in eight of the strains tested. All strains contained a glucose disaccharide which we have tentatively identified as trehalose on the basis of (i) comparative thin-layer and paper chromatography with standards, (ii) examination of the hydrolyzed product, and (iii) tests for reducing versus nonreducing sugars. In addition, a hexose with the chromatographic properties of glucose was observed in cultures grown on M6B complex medium. The presence of the phospholipids in Frankia strains was not affected by the age of the culture or the media on which they grew. However, the disaccharide was not pre...

The role of lipids in the growth of Frankia isolates

Abstract: A comparison is made of the lipid requirements of some Frankia strains. Root-extract lipids from alder were essential for the isolation of Frankia strains from all nodules of Alnus glutinosa, Hippophae rhamnoides, and in one case of Myrica gale and, at least in the case of A. glutinosa, they cannot be replaced by lecithin, Tween 80, or propionate. Many strains no longer need these lipids during subsequent cultivation. Strains from the spore-negative nodules of A. glutinosa need the lipids even after prolonged cultivation on most media, though they can adapt to media with propionate but without root-extract lipids after several transfers. These adapted strains must be distinguished from occasional revertants which, moreover, have a reduced infectivity. The results of silica-gel column and thin-layer chromatographic analysis combined with alkaline hydrolysis indicate that the active factors in the root-extract lipids are special fatty acids either in free or in bound form.

In vitro morphogenesis and ultrastructure of a Frankia sp. ArI3 (Actinomycetales) from Alnus rubra and a morphologically similar isolate (AirI2) from Alnus incana subsp. rugosa

Abstract: An actinomycete (AirI2) with black spores was isolated from nodules of Alnus incana ssp. rugosa. Although this organism is very different in appearance from the typically white strains of Frankia from Alnus, it has all the main microscopic features of members of this genus. However, cytological differences have been observed when compared with a strain with white spores (ArI3).

Influence de quelques herbicides à large spectre sur la croissance et l'infectivité de cultures pures de Frankia

Abstract: L'influence de 4 herbicides couramment utilises en agriculture sur la croissance, la morphologie et l'infectivite de cultures pures de Frankia a ete etudiee. Aux doses prescrites par le fabricant, la croissance des cultures et la morphologie de Frankia ne sont pratiquement pas affectees par le Legurame, le Devrinol ou le Fulton. A fortes concentrations le Comodor inhibe totalement la croissance de certaines souches. La formation de nodules est fortement affectee par tous les herbicides utilises.

Effect of L-methionine-DL-sulfoximine on acetylene reduction and vesicle formation in derepressed cultures of Frankia strain D11

Abstract: L-Methionine-DL-sulfoximine, a glutamate analog known to inhibit glutamine synthetase (GS) and glutamate synthase (GOGAT), allowed nitrogenase biosynthesis by Frankia strain D11 in presence of NH4+. GS activity, detected in cell-free extracts of D11, was higher in N2-fixing than in nonfixing conditions. These facts suggested that nitrogenase biosynthesis in Frankia was probably regulated by GS, GOGAT, or a product of their reaction, but regulation of GS by an adenylylation–unadenylylation system was probably not involved. Similarities between Frankia and Anabaena cylindrica were stressed.

Dinitrogen fixation and nodulation by Frankia in Alnus incana as affected by inorganic nitrogen in pot experiments with peat

Abstract: The effects of single large or repeated, exponentially increasing applications of nutrients, with or without inorganic nitrogen and at two pH levels, on the growth, nodulation, acetylene reduction, and nutrient uptake in Alnus incana (L.) Moench were investigated in pot experiments with peat under controlled laboratory conditions. The repeated application of inorganic nitrogen did not suppress nitrogenase activity until the last 2 weeks, whereas an initial, large, nitrogen application effectively inhibited nodulation and activity throughout the 40-day experimental period. The mode of nitrogen application was thus found to be more important than the total amounts applied. Shoot length, leaf area, shoot–root relations, dry-matter production, and nitrogen contents of plants were determined at the end of the experiment, as well as the effect of Frankia inoculations. Nitrogenase activity was determined three times, at 0, 3, and 5 weeks. N2 fixation (balance/acetylene reduction) was found to be maximal, 55% of ...

Axenic nodulation of in vitro propagated Alnus glutinosa plantlets by Frankia strains

Abstract: Two clones of Alnus glutinosa plantlets propagated in vitro were inoculated, under axenic conditions, with eight different isolates of Frankia originating from different provenances and representing both type-N and type-P strains. All the plants inoculated formed typical and effective actinorhizae. The nodulated root systems were tested for the presence of microbial contaminants on different culture media. Typical Frankia colonies, growing on the root pieces incubated in the culture media, were subcultured and reinoculated on alder seedlings grown in plastic growth pouches. The results demonstrated that Frankia can induce a typical and effective nodulation on axenic Alnus glutinosa host plants without the help of any "microbial helper".