Emerson enhancement of carbon fixation but not of acetylene reduction (nitrogenase activity) in Anabaena cylindrica

Planta ◽  
1973 ◽  
Vol 109 (1) ◽  
pp. 27-38 ◽  
Author(s):  
R. L. Lyne ◽  
W. D. P. Stewart
Keyword(s):  
Acetylene Reduction ◽  
Carbon Fixation ◽  
Nitrogenase Activity ◽  
Anabaena Cylindrica

Rehydration response of nitrogenase activity and carbon fixation in terrestrial Nostoc commune from Stipa–Bouteloa grassland

1983 ◽  
Vol 61 (10) ◽  
pp. 2658-2668 ◽  
Author(s):  
D. S. Coxson ◽  
K. A. Kershaw
Keyword(s):  
Respiratory Burst ◽  
Acetylene Reduction ◽  
Carbon Fixation ◽  
Light Exposure ◽  
Nitrogenase Activity ◽  
Net Photosynthesis ◽  
Rapid Decline ◽  
Carbon Dioxide Exchange ◽  
Nostoc Commune ◽  
Lower Temperature

The effects of wetting–drying cycles on patterns of carbon dioxide exchange and acetylene reduction were examined for colonies of the terrestrial cyanophyte Nostoc commune collected from a semiarid grassland site in southern Alberta, Canada. At 14 and 21 °C acetylene reduction takes ca. 14 h to resume maximal rates, although activity is detected within minutes of rehydration. Net photosynthesis reaches compensation minutes after rehydration and is maximal in under 80 min at 21 °C. No respiratory burst is evident, either for replicates previously dried rapidly (0.5 h) or slowly (5 h). In marked contrast, however, at 7 °C only minimal recovery of acetylene reduction is evident after 48 h diurnal treatment, while net photosynthesis requires a recovery time of 6 h. Again no respiratory burst is evident. After rehydration, the magnitude of acetylene reduction is strongly dependent on both the previous illumination level and temperature. The rapid decline in activity on transfer to darkness or on addition of 3-(3,4-dichlorophenyl)-1,1-dimethylurea can be moderated by increasing the duration of the previous light exposure or by incubation at lower temperature. This suggests the presence of substrate pools, the replenishment of which by photosynthesis allows oxidative phosphorylative support of nitrogenase activity in the dark. The extreme resistance of N. commune to desiccation and heat stress combined with its ability to resume metabolic activity within minutes of wetting should allow very effective utilization of small precipitation events during the summer months. The slower recovery of nitrogenase activity upon rehydration at lower temperatures may restrict winter field activity on rare occasions when thalli become dehydrated between snowfall periods.

Photorespiration and nitrogenase activity in the blue-green alga, Anabaena cylindrica

1972 ◽  
Vol 180 (1058) ◽  
pp. 87-102 ◽  
Keyword(s):  
Green Alga ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Dark Respiration ◽  
Reducing Power ◽  
Blue Green Alga ◽  
Anabaena Cylindrica ◽  
Oxygen Inhibition ◽  
Highly Sensitive ◽  
Photosynthetic Oxygen

Oxygen uptake in the light (photorespiration) by the nitrogen-fixing blue-green alga Anabaena cylindrica may be up to twenty times the dark respiration rate. The rate of uptake in the light increases linearly with increasing p O 2 while dark respiration is saturated at a p O 2 near 0.05 atm. Photorespiration is inhibited rapidly and completely by DCMU (3 x 10 -5 m) but KCN (10 -4 m) has little effect. Exogenously supplied hydroxyethane sulphonate (10 -5 m), an inhibitor of glycollate oxidase activity, and glycollate do not affect respiration, although 14 C-labelled glycollate is assimilated in the light and in the dark. Photorespiration is highly sensitive to p CO 2 and to NaHCO 3 concentration and approaches true photosynthetic oxygen production at the CO 2 compensation point of 10 parts/10 6 . A CO 2 concentration of 0.02 atm completely inhibits photorespiration whereas true photosynthesis is scarcely affected. Conditions which stimulate photorespiration (low p CO 2 and high p O 2 ) progressively inhibit acetylene reduction. In short-term studies DCMU inhibits acetylene reduction under condi­tions which stimulate photorespiration but has little effect under conditions which inhibit photorespiration. The results suggest that photorespiration and nitrogenase activity com­pete indirectly for reducing power and that at least one mechanism of oxygen inhibition of nitrogenase activity is via a stimulation of photorespiration.

The effect of light-dependent oxygen consumption on nitrogenase activity in Anabaena cylindrica

1986 ◽  
Vol 64 (9) ◽  
pp. 1843-1848 ◽  
Author(s):  
Donald L. Smith ◽  
David G. Patriquin ◽  
Margareta Dijak ◽  
George M. Curry
Keyword(s):  
Oxygen Consumption ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Dark Respiration ◽  
Anabaena Cylindrica ◽  
Heat Treated ◽  
Carbonyl Cyanide ◽  
Photosynthetic Oxygen ◽  
Similar Decrease ◽  
Effect Of Light

Light-dependent oxygen consumption (LDOC) was observed in isolated heterocysts and in intact and sonicated CO2-fixing Anabaena cylindrica cells. The rate of LDOC in heterocysts was about three times that of CO2-fixing cells. Photosynthetic oxygen production by A. cylindrica became light saturated at 0.3 to 0.5 mW cm−2. LDOC and nitrogenase activity (acetylene reduction) increased with light intensity up to 2.5 mW cm−2 and incubation under air resulted in much larger relative acetylene reduction increases than incubation under N2. Carbonyl cyanide-m-chlorophenyl-hydrazone, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and cyanide did not affect the rate of LDOC in isolated heterocysts or cell-free preparations of CO2-fixing cells. However, all three substances induced LDOC in CO2-fixing cells. Heat treatment (100 °C for 1 min) caused a doubling of LDOC. Depletion of reduced carbon reserves by dark incubation caused a similar decrease in LDOC and dark respiration. The higher rates of LDOC observed in heat-treated materials were removed by catalase, but not by superoxide dismutase. Catalase injection released half of the O2 consumed through LDOC by heated preparations. LDOC increased with temperature up to 85 °C, and increased threefold with pH between pH 10 and 11.5. The possibility that LDOC may act to protect the nitrogenase of the heterocyst from oxygen inactivation is discussed.

Estimating Nitrogenase Activity of Faba Bean (Vicia faba) by Acetylene Reduction (Ar) Assay

1990 ◽  
Vol 17 (5) ◽  
pp. 489 ◽  
Author(s):  
Herdina ◽  
JH Silsbury
Keyword(s):  
Diurnal Variation ◽  
Vicia Faba ◽  
Faba Bean ◽  
Closed System ◽  
N2 Fixation ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Electron Flow ◽  
Specific Rate ◽  
Rooting Medium

Methods of conducting acetylene reduction (AR) assay were appraised for estimating the nitrogenase activity of nodules of faba bean (Vicia faba L.). Factors considered were: (i) disturbance of plants when removing the rooting medium; (ii) assay temperature; (iii) the use of whole plants rather than detached, nodulated roots; (iv) diurnal variation in nodule activity; and (v) a decline in C2H4 production after exposure to C2H2. Plants growing in jars of 'oil dry' (calcined clay) had the same AR activity when assayed in situ in a closed system as when assayed after removal of the rooting medium. Assay temperatures of 12.5, 17.5 and 22.5°C influenced the specific rate of AR with the optimum at 17.5°C. Removal of the shoot resulted in a rapid decrease in AR activity in both vegetative and reproductive plants but the effect was much larger in the latter. AR and respiration by nodulated roots were closely linked and both varied markedly over a diurnal 12 h/12 h cycle. Since no fluctuation was found after nodules were detached, diurnal variation in the respiration of nodulated roots is attributed to change in nodule activity. Half of the dark respiration of nodulated roots was associated with respiration of the nodules and thus largely with N2 fixation. Since the AR assay provides no information on how electron flow in vivo is partitioned between reduction of N2 and reduction of protons, diurnal variation in hydrogen evolution (HE) in air and Ar/O2 in an open system was used to estimate this partitioning. Diurnal variation in apparent N2 fixation estimated in this manner was examined at a 'low' PPFD (300 μmol m-2 s-1) and at 'high' (1300 μmol m-2 s-1) to explore whether variation could be attributed to change in carbohydrate supply. Although HE in air and in Ar/O2 were both closely linked with the respiration of the nodulated root, apparent N2 fixation showed only a slight diurnal variation at 'low' light and almost none at 'high'. Vegetative plants showed no C2H2-induced decline in activity with exposure to C2H2 but reproductive plants did. This difference appears to be an age effect rather than attributable to flowering per se, since a decline occurred even when plants were kept vegetative by disbudding. A closed system for AR assay appears satisfactory for vegetative faba bean but such an assay over a 40-min period during the reproductive stage would underestimate nitrogenase activity by about 20%.

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

1983 ◽  
Vol 61 (11) ◽  
pp. 2956-2963 ◽  
Author(s):  
U. Granhall ◽  
T. Ericsson ◽  
M. Clarholm
Keyword(s):  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Inorganic Nitrogen ◽  
Experimental Period ◽  
Alnus Incana ◽  
Nitrogen Application ◽  
Noticeable Effect ◽  
Essential Nutrients ◽  
Pot Experiments ◽  
Ph Level

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 total nitrogen uptake, in minus-N pots with single applications of essential nutrients. The fastest growth was, however, noted in pots with single applications of all nutrients, including N. Among the latter, pots inoculated with Frankia showed the best growth, in spite of low nitrogenase activity. The only noticeable effect of a raised pH level was a reduced endophyte activity in minus-N pots with single applications of essential nutrients, due to increased N mineralization in the peat.

scholarly journals Whole-Genome Transcriptional Profiling of Bradyrhizobium japonicum during Chemoautotrophic Growth

2008 ◽  
Vol 190 (20) ◽  
pp. 6697-6705 ◽  
Author(s):  
William L. Franck ◽  
Woo-Suk Chang ◽  
Jing Qiu ◽  
Masayuki Sugawara ◽  
Michael J. Sadowsky ◽  
...  
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Carbon Fixation ◽  
Cultured Cells ◽  
Isocitrate Lyase ◽  
Nitrogenase Activity ◽  
Glyoxylate Cycle ◽  
Transcriptional Profiling ◽  
Pentose Phosphate ◽  
Hydrogen Gas ◽  
Essential Components

ABSTRACT Bradyrhizobium japonicum is a facultative chemoautotroph capable of utilizing hydrogen gas as an electron donor in a respiratory chain terminated by oxygen to provide energy for cellular processes and carbon dioxide assimilation via a reductive pentose phosphate pathway. A transcriptomic analysis of B. japonicum cultured chemoautotrophically identified 1,485 transcripts, representing 17.5% of the genome, as differentially expressed when compared to heterotrophic cultures. Genetic determinants required for hydrogen utilization and carbon fixation, including the uptake hydrogenase system and components of the Calvin-Benson-Bassham cycle, were strongly induced in chemoautotrophically cultured cells. A putative isocitrate lyase (aceA; blr2455) was among the most strongly upregulated genes, suggesting a role for the glyoxylate cycle during chemoautotrophic growth. Addition of arabinose to chemoautotrophic cultures of B. japonicum did not significantly alter transcript profiles. Furthermore, a subset of nitrogen fixation genes was moderately induced during chemoautotrophic growth. In order to specifically address the role of isocitrate lyase and nitrogenase in chemoautotrophic growth, we cultured aceA, nifD, and nifH mutants under chemoautotrophic conditions. Growth of each mutant was similar to that of the wild type, indicating that the glyoxylate bypass and nitrogenase activity are not essential components of chemoautotrophy in B. japonicum.

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.

scholarly journals Studies on nitrogenase activity of diazotrophic isolates from different rice production systems

2016 ◽  
Vol 8 (1) ◽  
pp. 284-289
Author(s):  
S. Kanimoli ◽  
K. Kumar
Keyword(s):  
Acetylene Reduction ◽  
Tamil Nadu ◽  
Production Systems ◽  
Nitrogenase Activity ◽  
Rice Production ◽  
Lowland Rice ◽  
Aerobic Rice ◽  
Marked Variation ◽  
Reduction Assay ◽  
First Time

The present study was carried out to evaluate the nitrogen fixing ability of diazotrophs isolated from the rhizosphere soils of rice which were grown in three different rice growing systems. A total of hundred and ten isolates obtained were subjected to Acetylene Reduction Assay (ARA) and ninety eight isolates recorded significant amount of nitrogenase activity in a range of 185.73 to 3794.55 nmoles of ethylene mg of protein-1 h-1. The highest nitrogenase activity was recorded by Derxia (3794.55 nmoles of ethylene mg of protein-1 h-1) isolated from Trichy (lowland). Among the three different rice production systems, isolates obtained from lowland rice (Derxia – 3794.5 nmoles of ethylene mg of protein-1 h-1) recorded higher nitrogenase activity followed by Aerobic (Pseudomonas - 2194.89 nmoles of ethylene mg of protein-1 h-1) and SRI (Azotobacter - 1971.85 nmoles of ethylene mg of protein-1 h-1) rice isolates. The results revealed marked variation in the ARA of the diazotrophic isolates obtained from lowland, SRI and Aerobic rice. The nitrogenase activity of diazotrophs from rice fields have been reported earlier but the nitrogenase activity of diazotrophs from three different rice production systems from various parts of Tamil Nadu is reported for the first time from India.

scholarly journals Factors Influencing Nitrogenase Activity (Acetylene Reduction) by Root Nodules of Groundnut, Arachis hypogaea L.

1983 ◽  
Vol 10 (1) ◽  
pp. 26-29 ◽  
Author(s):  
P. T. C. Nambiar ◽  
P. J. Dart
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Activity Period ◽  
Diurnal Fluctuation ◽  
Factors Influencing ◽  
Arachis Hypogaea L ◽  
Reduction Assay

Abstract Acetylene reduction assay, used to measure nitrogenase activity of legume root nodules, is influenced by environmental factors, which limit its application. The effects of some of the environmental factors on acetylene reduction by groundnut root nodules are described. The activity was nonlinear during the first hour of incubation. Assay temperature above 25 C decreased the activity. Washing the nodulated roots prior to the assay also decreased the activity. The activity was influenced by light intensity, soil moisture, and moisture content in the incubation bottle. Diurnal fluctuation with one maximum and one minimum activity period during a 24 hour cycle was observed. Nitrogenase activity was higher during the postrainy season compared to that of the rainy season. A virginia cultivar Kadiri-71 had higher nitrogenase activity than a dwarf valencia cultivar, MH 2.

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