Factors affecting vesicle formation and acetylene reduction (nitrogenase activity) in Frankia sp. CpI1

1981 ◽  
Vol 27 (8) ◽  
pp. 815-823 ◽  
Author(s):  
John D. Tjepkema ◽  
William Ormerod ◽  
John G. Torrey
Keyword(s):  
Acetylene Reduction ◽  
Ethylenediaminetetraacetic Acid ◽  
Nitrogenase Activity ◽  
Carbon Sources ◽  
Vesicle Formation ◽  
Free Medium ◽  
Factors Affecting ◽  
Reducing Activity ◽  
Acetylene Reducing Activity

Vesicle formation and acetylene reduction (nitrogenase activity) were observed when washed hyphae from cultures of Frankia sp. CpI1 were transferred to a nitrogen-free medium containing ethylenediaminetetraacetic acid and succinate. Succinate could be replaced by malate or fumarate, but not other carbon sources. Maximum acetylene reduction and vesicle numbers were observed at a pH of 6.0–6.5, at 25–30 °C, and at atmospheric [Formula: see text] or somewhat less (5–20 kPa). Addition of 1 mM NH4Cl almost completely inhibited vesicle formation and acetylene-reducing activity, but did not immediately inhibit such reducing activity by cultures with preexisting vesicles. Acetylene-reducing activity was never observed in the absence of vesicle formation.

Nitrogen fixation (acetylene reduction) by Klebsiella pneumoniae in association with 'Park' Kentucky bluegrass (Poa pratensis L.)

1981 ◽  
Vol 27 (1) ◽  
pp. 52-56 ◽  
Author(s):  
L. V. Wood ◽  
R. V. Klucas ◽  
R. C. Shearman
Keyword(s):  
Nitrogen Fixation ◽  
Klebsiella Pneumoniae ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Surface Sterilization ◽  
Reducing Activity ◽  
Acetylene Reducing Activity

Turfs of 'Park' Kentucky bluegrass reestablished in the greenhouse and inoculated with Klebsiella pneumoniae (W6) showed significantly increased nitrogen fixation (acetylene reduction) compared with control turfs. Mean ethylene production rates per pot were 368 nmol h−1 for K. pneumoniae treated turfs, 55 nmol h−1 for heat-killed K. pneumoniae treated turfs, and 44 nmol h−1 for untreated turfs. Calculated lag periods before activity was observed were generally very short (less than 1 h).When 'Park' Kentucky bluegrass was grown from seed on soil-less medium of Turface, a fired aggregate clay, inoculation with K. pneumoniae (W6) resulted in 9 of 11 turfs showing nitrogenase activity (mean ethylene producion rate per pot was 195 nmol h−1). Only 3 of 11 turfs treated with heat-killed K. pneumoniae showed any activity and their mean rate of ethylene production (40 nmol h−1 per pot) was significantly lower than that for turfs treated with K. pneumoniae.Using the 'Park'–Turface soil-less model system it was shown that acetylene reducing activity was (i) root associated, (ii) generally highest at a depth of 1–4 cm below the surface, (iii) enhanced by washing excised roots, and (iv) inhibited by surface sterilization of excised roots. Klebsiella pneumoniae was recovered from Turface and roots showing acetylene reducing activity.

Kinetics of first-cutting regrowth of alfalfa plants and nitrogenase activity in a controlled environment with and without added nitrate

1983 ◽  
Vol 61 (9) ◽  
pp. 2405-2409 ◽  
Author(s):  
F. D. H. Macdowall
Keyword(s):  
Dry Matter ◽  
Rhizobium Meliloti ◽  
Nitrogenase Activity ◽  
Radical Change ◽  
N Nutrition ◽  
Meliloti Strain ◽  
Medicago Sativa L ◽  
Reducing Activity ◽  
Acetylene Reducing Activity ◽  
Kinetics Of

Seedlings of Medicago sativa L. cv. Algonquin were grown in vermiculite and nodulated by Rhizobium meliloti strain 102F70 at two lower levels of N, until flowering when the tops were cut off to leave about 10% shoot stubble. Residual shoot dry matter immediately resumed first-order growth and maintained it throughout regrowth to second flowering. The rate constants of shoot regrowth were 34% lower (at 15 mM NO3−), 25% lower (at 1.5 mM NO3− symbiotically), or 220% higher (at zero NO3− symbiotically) than the values for 1 to 4-week-old seedlings, which indicated a radical change in physiology. Root dry matter resumed exponential growth after a 7-day recession and its recovery and yields were independent of N nutrition. The most pronounced minima occurred in the acetylene-reducing activity of nitrogenase, the kinetics of which paralleled root dry matter except that its redevelopment stopped after two-thirds of the regrowth time. The rate coefficient for the redevelopment of nitrogenase activity equalled that for its development during the seedling stage, which suggested unchanged limitations on that process until its redevelopment stopped.

Relative contributions to nitrogenase (acetylene reducing) activity of stem and root nodules in Sesbania rostrata

1992 ◽  
Vol 38 (6) ◽  
pp. 577-583 ◽  
Author(s):  
J. K. Ladha ◽  
Minviluz Garcia ◽  
R. P. Pareek ◽  
G. Rarivoson
Keyword(s):  
Acetylene Reduction ◽  
Root Nodule ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Dry Weight ◽  
Acetylene Reduction Activity ◽  
Sesbania Rostrata ◽  
Reduction Activity ◽  
Acetylene Reducing Activity ◽  
Aerial Stem

Six experiments, two each in the phytotron, greenhouse, and field, were conducted to assess the contribution of nitrogenase activity (acetylene reduction) by stem nodules in the presence and absence of root nodules of Sesbania rostrata (Brem & Oberm). In a greenhouse experiment, the effect of detaching already formed aerial stem nodules on the restoration of root nodules and nitrogenase activity was studied. The field experiment compared nodulation and acetylene-reduction activity by dual-nodulating S. rostrata and root-nodulating Sesbania cannabina. Acetylene-reduction activity expressed per gram of nodule dry weight was higher for stem nodules than for root nodules. Root nodule dry weight and acetylene-reduction activity failed to increase after stem inoculation, but root nodule dry weight and acetylene-reduction activity increased several fold within 15 days of detachment of aerial stem nodules. Stem nodulation, which occurred without inoculation under lowland field condition, suppressed root nodulation, thus accounting for more than 75% of total nitrogenase activity. Sesbania rostrata showed higher acetylene-reduction activity than S. cannabina. In dual-nodulating plants, root and stem nodules appeared to strike a balance in competition for energy, which may be controlled by stem nodulation. Key words: Sesbania rostrata, Azorhizobium caulinodans, stem nodule, root nodule, acetylene-reducing activity.

scholarly journals (349) Fertilizer-N Effectson Cycas–Nostoc Symbiosis

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1061A-1061
Author(s):  
Laura M. R. Rinaldi ◽  
Maria C. Margheri ◽  
Alba Ena
Keyword(s):  
Nutrient Solution ◽  
Nitrogenase Activity ◽  
Growth Cycle ◽  
N Fertilization ◽  
Fertilizer N ◽  
Reducing Activity ◽  
Acetylene Reducing Activity ◽  
Nitrogen Treatments ◽  
Indoor And Outdoor

Cycasrevoluta Thunb., cultivated as an ornamental plant for indoor and outdoor use, is characterized by an extremely slow rate of growth. In spite of the occurrence in its coralloid roots of the nitrogen-fixing cyanobiont Nostoc, N fertilization is commonly used to accelerate Cycas growth. A greenhouse experiment was conducted to examine the effects of two forms of combined N on growth of Cycas plants and cyanobacterial nitrogenase activity, measured on intact plants. Cycas plants grown in pots were fertilized from June to September with nutrient solution containing macronutrients as P, K, Mg, and Hoagland's micronutrients. N (700 mg/plant) was supplied as KNO3, or applied as NH4NO3; control plants received nutrient solution without nitrogen. Treatments were applied monthly and repeated for three times. Each treatment consisted of 15 plants. The length of the new leaves was recorded during the growth cycle of the plants. The nitrogenase activity, based on acetylene reducing activity (ARA), was measured on the plants in situ in July and in October. N fertilization stimulated both the nitrogenase activity and the growth of the plants. In comparison with the control, average increases in ARA of more than 20% were observed in the treated plants. Nitrogenase activity was slightly better in the presence of NH4NO3 in July, whereas the values measured in October were about the same for two treatments. The two forms of nitrogen were the same also regarding the stimulus on growth: in N-treated plants the total length of the new leaves was more than double with respect to the control at the end of the growing season. Control plants grown without fertilizer N had a slow start to their growth cycles and were unable to recover and compensate later for the lack of transient N.

scholarly journals Nitrogenase of Klebsiella pneumoniae. Inhibition of acetylene reduction by magnesium ion explained by the formation of an inactive dimagnesium–adenosine triphosphate complex

1974 ◽  
Vol 139 (1) ◽  
pp. 211-214 ◽  
Author(s):  
Roger N. F. Thorneley ◽  
Keith R. Willison
Keyword(s):  
Klebsiella Pneumoniae ◽  
Adenosine Triphosphate ◽  
Acetylene Reduction ◽  
Inhibitory Effect ◽  
Magnesium Ion ◽  
Active Substrate ◽  
Reducing Activity ◽  
Acetylene Reducing Activity

Acetylene-reducing activity of purified nitrogenase from Klebsiella pneumoniae was studied over a range of ATP and Mg2+ concentrations at 15°C, pH7.8. Inhibition at Mg2+ concentrations of 2.5–30mm was due to the formation of the inactive complex, Mg2ATP. At higher Mg2+ concentrations an additional inhibitory effect was observed. The results were consistent with a MgATP complex being the active substrate with an apparent Km(MgATP)=0.4mm.

A comparison of carbon source utilization for growth and nitrogenase activity in two Frankia isolates

1986 ◽  
Vol 32 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Mary F. Lopez ◽  
Patricia Young ◽  
John G. Torrey
Keyword(s):  
Nitrogen Fixation ◽  
Carbon Source ◽  
Oxygen Uptake ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Carbon Sources ◽  
Alnus Rubra ◽  
Nitrogen Fixing ◽  
Pure Cultures

The carbon source requirements for the growth and nitrogen fixation of two morphologically distinct Frankia isolates were examined. Isolate ArI3 (from Alnus rubra) grew well on propionate, malate, acetate, and trehalose, and isolate CcI2 (from Casuarina cunninghamiana) grew best on pyruvate, acetate, and propionate. In general, the same carbon sources that supported growth supported both the development of vesicles and nitrogenase activity in long-term induction experiments in both isolates. However, ArI3 cultures induced on proprionate had 7 to 26 times the activity of other carbon sources and ArI3 cultures induced on acetate did not develop any detectable acetylene reduction. In a parallel set of experiments, cultures of both isolates were induced for nitrogenase activity on propionate and the resulting nitrogen fixing cultures were washed free of the organic acid by centrifugation. The washed cultures were incubated in the presence of various carbon sources to determine the ability of a particular substrate to supply energy directly for nitrogen fixation when vesicles and nitrogenase were already present. As was observed in the long-term induction experiments, pyruvate, propionate, and acetate supported the greatest activity in CcI2. Succinate and malate supported the greatest activity in ArI3, and propionate had very little stimulation of acetylene reduction. The reason for the lack of stimulation by propionate for washed cells of ArI3 was unclear but may have been due to toxic concentrations of the organic acid. In an attempt to compare the carbon utilization of ArI3 in pure culture with that in the alder symbiosis, oxygen uptake in the presence of various carbon sources of vesicles clusters isolate from Alnus rubra nodules inoculated with ArI3 was compared with the oxygen uptake of nitrogen-fixing pure cultures of ArI3. The oxygen uptake of the isolated vesicle clusters was stimulated by sucrose, trehalose, and glucose, but not by a variety of organic acids. In comparison, nitrogen-fixing pure cultures of ArI3 readily oxidized sugars and organic acids.

Etude de la dynamique de l'azote à haute altitude. I. Fixation d'azote (réduction de l'acétylène) par Alnus viridis

1979 ◽  
Vol 57 (19) ◽  
pp. 1979-1985 ◽  
Author(s):  
André Moiroud ◽  
André Capellano
Keyword(s):  
Reduction Method ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Cold Climate ◽  
Green Alder ◽  
Alnus Viridis ◽  
Reducing Activity ◽  
Diurnal Fluctuations ◽  
Acetylene Reducing Activity ◽  
Vegetative Season

During two vegetative seasons (1977, 1978), Alnus viridis Chaix root nodules were incubated in the field and assayed for nitrogen fixing activity by acetylene reduction method. In green alder the nitrogenase activity took place with the first opening of buds (June); maximum values were attained in July–August; the activity decreased steadily until leaf fall, and then ceased. Diurnal fluctuations in acetylene reducing activity were observed, the 1400-hour values were twice those of 1000 hours. The optimal temperature for nitrogenase activity was below 20 °C; this fact would be in relation with better adaptation of Alnus viridis to cold climate. The nodular biomass being only 40 kg/ha, the nitrogen fixed during the vegetative season (mid-June to mid-October) was only about 8 kg/ha. Symbiotic fixation accounted for only 10% of the nitrogen requirements of green alder.

ATP and acetylene-reducing activity of a sulfate-reducing bacterium

1977 ◽  
Vol 23 (5) ◽  
pp. 567-572 ◽  
Author(s):  
T. Sekiguchi ◽  
A. Noguchi ◽  
Y. Nosoh
Keyword(s):  
Energy Source ◽  
Sulfate Reduction ◽  
Acetylene Reduction ◽  
Adenine Nucleotides ◽  
Desulfovibrio Vulgaris ◽  
Atp Level ◽  
Sulfate Reducing ◽  
Reducing Activity ◽  
Acetylene Reducing Activity

A sulfate-reducing bacterium, a strain of Desulfovibrio vulgaris, when lactate or pyruvate was supplied as an electron and energy source, reduced acetylene only in the presence of sulfate. Acetylene reduction started after a lag of 1 h. H2 which acts as an electron and energy source for sulfate reduction was unable to reduce acetylene even in the presence of sulfate. It was suggested, from the measurements of the amounts of adenine nucleotides of the bacterium incubated under various conditions, that the bacterium is able to reduce acetylene at a high ATP level or a high ATP/ADP ratio.

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