Physiology of Ex Planta Nitrogenase Activity in Rhizobium japonicum†

Induced by soy bean tissue cultures in socalled “tissue chambers”, Rhizobium japonicum str. 61-A-96 developed nitrogenase activity separated from the plant cells. The activity proceded for 48 h with a rate of 1 × 10-8 nmol C2H4 h-1 cell-1, which is about 6% of the activity measured for bacteroids from Rhizobium japonicum in nodules of Glycine max.

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Differentiation of Rhizobium japonicum, III. Inhibition of Nitrogenase Derepression by Chloramphenicol and Rifampicin Concentrations, Not Inhibiting Growth

Zeitschrift für Naturforschung C ◽

10.1515/znc-1978-11-1210 ◽

1978 ◽

Vol 33 (11-12) ◽

pp. 859-862 ◽

Cited By ~ 9

Author(s):

D. Werner

Keyword(s):

Gas Phase ◽

Doubling Time ◽

Slow Growth ◽

Nitrogenase Activity ◽

Cell Number ◽

Culture Conditions ◽

Rhizobium Japonicum ◽

Cell Protein ◽

Yeast Extract Mannitol ◽

Glycerol Medium

Development of nitrogenase (40 -140 nmol C2 H4 · mg protein-1· h-1) in Rhizobium japonicum 61-A-101 after transfer to special culture conditions (medium 20 P, 2% O2, 10% CO2, 88% N2 in the gas phase) is inhibited by chloramphenicol (6X 10-4 ·1O-3 м) and by rifampicin (10-5м). These concentrations do not inhibit the slow growth of the cells under these conditions with a doubling time of the cell protein and living cell number of 3 - 5 d. Nitrogenase activity of previously derepressed cells is not inhibited by chloramphenicol. Growth of the cells under air in yeast extract-mannitol-glycerol medium (8 h doubling time) is affected significantly more by chloramphenicol (2.5 · 10-4 м) than growth under nitrogenase derepressed culture conditions.

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Plant Peptidoglucans Affecting the Phenotypic Expression of Rhizobial Nitrogenase

Functional Plant Biology ◽

10.1071/pp9800251 ◽

1980 ◽

Vol 7 (3) ◽

pp. 251 ◽

Cited By ~ 2

Author(s):

R Storey ◽

M Reporter

Keyword(s):

Nitrogenase Activity ◽

Phenotypic Expression ◽

Deae Cellulose ◽

H2 Production ◽

Rhizobium Japonicum ◽

Small Peptide ◽

Root Cells ◽

Rhizobium Strains ◽

Hydrolysis Of

Dialysable substances capable of influencing rhizobial nitrogenase activity in vitro were obtained from Glycine max root cells during transfilter coculture with Rhizobium japonicum. These substances from the liquid plant-conditioned medium were chromatographed on Sephadex G-25, DEAE- cellulose and carboxymethylcellulose and on a concanavalin A-Sepharose column. The separated active column fractions initiated the phenotypic expression of nitrogenase activity (C2H2 reduction, H2 production) in different Rhizobium strains. Hydrolysis of these column fractions showed them to contain a small peptide and a glucan. Analysis of active fractions also showed the presence of bound copper. It was concluded that the plant fractions involved in stimulating rhizobial nitrogenase activity were peptidoglucans; at least one active fraction may also be a copper metallothionein.

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Low root temperatures and nitrogenase activity in soybean

Canadian Journal of Botany ◽

10.1139/b84-135 ◽

1984 ◽

Vol 62 (5) ◽

pp. 965-971 ◽

Cited By ~ 35

Author(s):

D. B. Layzell ◽

P. Rochman ◽

D. T. Canvin

Keyword(s):

Gas Exchange ◽

Relative Efficiency ◽

Nitrogenase Activity ◽

Temperature Drop ◽

Relative Increase ◽

Rhizobium Japonicum ◽

Hydrogenase Activity ◽

Symbiotic Association ◽

Short Term ◽

Gas Exchange System

A continuously flowing open gas exchange system was used to monitor the rates of CO2 evolution, C2H2 reduction, and H2 evolution from intact nodulated soybean ('Harosoy 63') roots, while root temperatures were dropped from the growing temperature (25 °C) to 10 °C at the rate of 5 °C/h. Four Rhizobium japonicum inoculants were used, three of which (type S (Nitragin Co.), USDA 16, USDA 35) displayed net H2 evolution while the fourth (USDA 110) did not evolve H2. Between 25 and 15 °C, values for Q10 in the H2-evolving symbioses ranged from 2.0 to 2.7 for CO2 evolution. 1.3 to 2.4 for C2H2 reduction, and 3.2 to 3.7 for H2 evolution. Nodulated roots of USDA 110 displayed the highest Q10 values for both CO2 evolution (Q10 = 2.9) and C2H2 reduction (Q10 = 15.2). The temperature profiles of these gas exchange measurements were used to calculate both the relative efficiency (RE = 1 − (H2 evolution/C2H2 reduction)) of N2 fixation and the ratio between CO2 evolution and C2H2 reduction at temperatures between 10 and 25 °C. The effect of short-term changes on the CO2/C2H2 ratio varied with symbiotic association. In the type-S symbiosis, long-term (96 h) treatments at low root temperature (9.5 °C) decreased the amount of CO2 evolved per C2H2 reduced to 35% of the value obtained at 25 °C. This study did not determine whether these observed changes were associated with N2 fixation or growth and maintenance of the nodulated root. In all H2-evolving symbioses, the RE increased from ca. 0.6 to 0.9 in response to a temperature drop from 25 to 10 °C. Studies of net H2 uptake and 3H2 exchange at 25 and 15 °C indicated that the observed changes in relative efficiency were due to variations in electron allocation by nitrogenase rather than a relative increase in uptake hydrogenase activity. The increase in RE above 0.75 suggested that lower temperatures may have altered the minimal nitrogenase electron allocation to less than one H2 per N2 fixed. This observed increase in RE with lower temperatures indicated that, in the symbioses studied, H2 evolution may have provided a buffer which permitted the maintenance of high levels of N2 fixation during short-term or diurnal fluctuations in soil temperature.

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Differentiation of Rhizobium japonicum. II. Enzymatic Activities in Bacteroids and Plant Cytoplasm during the Development of Nodules of Glycine max

Zeitschrift für Naturforschung C ◽

10.1515/znc-1978-5-612 ◽

1978 ◽

Vol 33 (5-6) ◽

pp. 373-381 ◽

Cited By ~ 33

Author(s):

R. Stripf ◽

D. Werner

Keyword(s):

Glycine Max ◽

Plant Cell ◽

Specific Activity ◽

Nitrogenase Activity ◽

Maximum Activity ◽

Rhizobium Japonicum ◽

Sharp Maximum ◽

Specific Activities ◽

Low Activity ◽

Japonicum Strain

Phytotron grown plants of Glycine max var. Caloria infected with Rhizobium japonicum 61-A-101 under controlled conditions as 14 d old seedlings develop a sharp maximum of nitrogenase activity of 13 ± 3 nmol C2H4 · h-1 · mg nodule fresh weight-1 19 d after infection, followed by a long period of reduced activity (3 -5 nmol) between 30 and 45 days after infection. A higher maximum activity (18 nmol C2H4 · h-1 · mg nodule-1, lasting 7 days was found in Glycine max var. Mandarin, with a similar peroid of low activity (3 - 4 nmol) following, between 35 and 50 d after infection. Nitrogenase activity in the varieties infected with Rhizobium japonicum strain 3I1 b 85 is very similar. In both varieties, the leghaemoglobin continues to increase (3 fold) after the maximum nitrogenase activity is reached and starts to decline only after 35 to 40 d. Specific activities of the three enzymes aspartate aminotransferase (E.C.2.6.1.1.), glutamate dehydrogenase (E.C.1.4.1.2.) and alanine aminotransferase (E.C.2.6.1.2.) in the plant cell cytoplasm are changing very similarly to nitrogenase activity in the bacteroids, whereas the specific activities of the three enzymes in the bacteroids decrease only very slightly between 19 and 45 d. For these 3 enzymes the specific activity in the bacteroids during the phase of maximum nitrogenase activity is only 20 - 40% of the specific activity in the cytoplasm. A constant low activity (0.350 units) of glutamine synthetase (E.C.6.3.1.2.) is found in bacteroids from 19 to 45 d old nodules, whereas the specific activity in the plant cytoplasm increases from about 1.2 units at 19 d to more than 6 units at 45 d. The specific activity of GOGAT (E.C.1.4.13.) in bacteroids is 2 - 3 times higher than in the plant cell cytoplasm and increases slightly. Alanine dehydrogenase (E.C.1.4.1.1.) and 3-hydroxybutyrate dehydrogenase (E.C.1.1.1.30.) activities in bacteroids increase between 19 and 35 d after infection by a factor of 2 - 3. In 35 - 45 d old nodules, the specific activity of aianine-dh in bacteroids of the same Rhizobium japonicum strain (61-A-101) from plant var. Caloria is significantly smaller than in bacteroids from plant var. Mandarin, whereas for 3-hydroxybutyrate-dh the activity in bacteroids from var. Caloria is enhanced compared to bacteroids from var. Mandarin.

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Requirement for Carbon Dioxide for Nonsymbiotic Expression of Rhizobium japonicum Nitrogenase Activity

Journal of Bacteriology ◽

10.1128/jb.152.1.510-513.1982 ◽

1982 ◽

Vol 152 (1) ◽

pp. 510-513

Author(s):

O. Mario Aguilar ◽

Gabriel Favelukes

Keyword(s):

Carbon Dioxide ◽

Nitrogenase Activity ◽

Rhizobium Japonicum ◽

Liquid Cultures

The expression and maintenance of nitrogenase (C 2 H 2 ) activity in growing, microaerobic liquid cultures of Rhizobium japonicum 3I1b110 was found to be stringently dependent on the sustained supply of CO 2 . This requirement for CO 2 appeared to exceed the basal requirement for growth and was not related to effects on pH.

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