Publications
Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
---|
dilution of liquid rhizobium cultures to increase production capacity of inoculant plants. | experiments were undertaken to test whether peat-based legume seed inoculants, which are prepared with liquid cultures that have been deliberately diluted, can attain and sustain acceptable numbers of viable rhizobia. liquid cultures of rhizobium japonicum and rhizobium phaseoli were diluted to give 10, 10, or 10 cells per ml, using either deionized water, quarter-strength yeast-mannitol broth, yeast-sucrose broth, or yeast-water. the variously diluted cultures were incorporated into gamma-irrad ... | 1982 | 16346075 |
variations in ability of rhizobium japonicum strains to nodulate soybeans and maintain fixation in the presence of nitrate. | this study investigated differences in sensitivity to nitrate of soybean (glycine max cv. davis) symbioses with 16 different rhizobium japonicum strains. when nitrate (20 mm) was added to established symbioses, there were no significant differences in the degree of inhibition of acetylene reduction for any of the 16 strains. when nitrate was present during the establishment of nodules, high levels of nitrate (10 mm) were equally inhibitory on all symbioses, whereas specific strain effects appear ... | 1982 | 16346093 |
enzymes of amide and ureide biogenesis in developing soybean nodules. | amide and ureide biogenic enzymes were measured in the plant fraction of soybean (glycine max) nodules during the period 11 to 23 days after inoculation with rhizobium japonicum (usda 3i1b142). enzymes involved in the initial assimilation of ammonia, i.e. glutamine synthetase, glutamate synthase, and aspartate aminotransferase, showed substantial increases in their specific activities over the time course. these increases paralleled the induction of nitrogenase activity in the bacteroid and legh ... | 1982 | 16662397 |
synthesis and accumulation of nitrite in soybean nodules supplied with nitrate. | nodulated soybean plants (glycine max [l.] merr) were grown in sand culture without combined n or with a continuous supply of nitrate in nutrient solution. moderate nitrate concentration (30 milligrams n per liter) had little effect on nodule weight/plant while high nitrate concentration (100 milligrams n per liter) depressed nodule weight/plant by 70 to 80% with harvests 30 to 60 days after planting and initiation of nitrate treatments.the effect of nitrate supply on ammonium, amino, and ureide ... | 1982 | 16662417 |
relative abundance of ureides and nitrate in plant tissues of soybean as a quantitative assay of nitrogen fixation. | the relationship between the relative abundance of ureides ([ureide-n/ureide-n plus nitrate-n] x 100) in the shoot axis (stems plus petioles), nodulated roots and leaflets of "bragg" soybean (glycine max [l.] merrill) and the symbiotic dependence of these plants was examined under glass-house conditions. plants, inoculated with effective rhizobium japonicum cb1809, were grown with their roots exposed continuously to a nutrient solution containing either 0, 1.5, 3.0, 6.0 or 12.0 millimolar no(3)- ... | 1982 | 16662425 |
respiratory and nitrogenase activities of soybean nodules formed by hydrogen uptake negative (hup) mutant and revertant strains of rhizobium japonicum characterized by protein patterns. | rates of respiratory co(2) loss and nitrogenase activities of h(2) uptake-negative mutant strains and h(2) uptake-positive revertant strains of rhizobium japonicum have been investigated. two-dimensional gel protein patterns of bacteroids formed by inoculation of soybeans (glycine max l.) with these two strains show that they are closely related and revealed only one obvious difference between them. on the basis of molecular weight standards, it was concluded that the missing protein spot in the ... | 1982 | 16662677 |
a comparative study of the physiology of symbioses formed by rhizobium japonicum with glycine max, vigna unguiculata, and macroptilium atropurpurem. | although rhizobium japonicum nodulates vigna unguiculata and macroptilium atropurpurem, little is known about the physiology of these symbioses. in this study, strains of r. japonicum of varying effectiveness on soybean were examined. the nonhomologous hosts were nodulated by all the strains tested, but effectiveness was not related to that of the homologous host. on siratro, compared to soybean, many strains reversed their relative effectiveness ranking. both siratro and cowpea produced more dr ... | 1982 | 16662732 |
spectral evidence for a component involved in hydrogen metabolism of soybean nodule bacteroids. | a component with a difference spectrum similar to that of b-type cytochromes which becomes reduced upon the addition of h(2) has been demonstrated in soybean nodule bacteroids. this electron carrier, referred to as component 559-h(2), is present in hydrogenase-positive strains of rhizobium japonicum but has not been detected in mutants that lack hydrogenase activity or in hydrogenase-negative wild-type strains. a positive correlation between concentrations of component 559-h(2) and hydrogenase a ... | 1982 | 16662741 |
nodulation of soybean byrhizobium japonicum mutants with altered capsule synthesis. | spontaneous mutants with altered capsule synthesis were isolated from a marked strain of the symbiont,rhizobium japonicum. differential centrifugation was used to enrich serially for mutants incapable of forming capsules. the desired mutants were detected by altered colony morphology and altered ability to bind host plant lectin. three mutants failed to form detectable capsules at any growth phase when cultured in vitro or in association with the host (soybean,glycine max (l.) merr.) roots. thes ... | 1982 | 24275968 |
glutamine synthetase, glutamate synthase and glutamate dehydrogenase in rhizobium japonicum strains grown in cultures and in bacteroids from root nodules of glycine max. | the growth yields of three strains of rhizobium japonicum (cb 1809, cc 723, cc 705) in culture solutions containing l-glutamate were about twice those grown with ammonium. the activities of glutamine synthetase (gs; ec 6.3.1.2) and glutamate dehydrogenase (gdh; ec 1.4.1.4) were dependent on the nitrogen source in the medium and also varied with growth. both nadph-and nadh-dependent glutamate synthase (gogat; ec 1.4.1.13) and nadph-dependent gdh were found in strains grown with either glutamate o ... | 1983 | 24258169 |
lectin in five soybean cultivars previously considered to be lectin-negative. | hemagglutinating proteins were isolated by affinity chromatography from seeds of each of five cultivars of soybeans (clycine max (l.) merr.) previously reported to lack detectable lectin (s.p. pull et al., 1978; science 200, 1277). quantities were between 1,000 and 10,000 times less than that found in the seeds of the reference cultivar, chippewa. the sensitivity of the hemagglutinating assay was 0.05 μg ml(-1). hemagglutinating activity was demonstrated in affinity-purified fractions from bulk ... | 1983 | 24264541 |
cytochromes of rhizobium japonicum 61a76 bacteroids from soybean nodules. | bacteroids of rhizobium japonicum 61a76 were isolated from nodules of field-grown soybean plants by sucrose density gradient fractionation. the major cytochromes, aa(3), b, c, and possibly o were present in the bacteroids throughout the active nitrogen-fixing life of the nodule. this is in contrast with previous reports using other r. japonicum strains in which cyotchromes aa(3) and o were not found. | 1983 | 16662786 |
nitrate and nitrite reduction in relation to nitrogenase activity in soybean nodules and rhizobium japonicum bacteroids. | soybean (glycine max l. cv williams) seeds were sown in pots containing a 1:1 perlite-vermiculite mixture and grown under greenhouse conditions. nodules were initiated with a nitrate reductase expressing strain of rhizobium japonicum, usda 110, or with nitrate reductase nonexpressing mutants (nr(-) 108, nr(-) 303) derived from usda 110. nodules initiated with either type of strain were normal in appearance and demonstrated nitrogenase activity (acetylene reduction). the in vivo nitrate reductase ... | 1983 | 16662897 |
enzymes of ureide synthesis in pea and soybean. | soybean (glycine max) and pea (pisum sativum) differ in the transport of fixed nitrogen from nodules to shoots. the dominant nitrogen transport compounds for soybean are ureides, while amides dominate in pea. a possible enzymic basis for this difference was examined.the level of enzymes involved in the formation of the ureides allantoin and allantoic acid from inosine 5'-monophosphate (imp) was compared in different tissues of pea and soybean. two enzymes, 5'-nucleotidase and uricase, from soybe ... | 1983 | 16662981 |
metabolism of c-labeled photosynthate and distribution of enzymes of glucose metabolism in soybean nodules. | the metabolism of translocated photosynthate by soybean (glycine max l. merr.) nodules was investigated by (14)co(2)-labeling studies and analysis of nodule enzymes. plants were exposed to (14)co(2) for 30 minutes, followed by (12)co(2) for up to 5 hours. the largest amount of radioactivity in nodules was recovered in neutral sugars at all sampling times. the organic acid fraction of the cytosol was labeled rapidly. although cyclitols and malonate were found in high concentrations in the nodules ... | 1983 | 16663058 |
a rapid regulatory response governing nodulation in soybean. | the number of nodules which develop on the primary root of soybean seedlings (glycine max l. merr) after inoculation with rhizobium japonicum is substantially diminished in the region of the root developmentally 10 to 15 hours younger than the region maximally susceptible to nodulation at the time of inoculation. this rapid inhibition of nodulation has been investigated by inoculating soybean seedlings with rhizobia at two different times, 15 hours apart. living r. japonicum cells, but not heter ... | 1983 | 16663209 |
construction of a rhizobium japonicum gene bank and use in isolation of a hydrogen uptake gene. | a gene bank of rhizobium japonicum dna was constructed by using the broad host range conjugative cosmid plafr1. eighty-three percent of the clones in the bank contained cosmids with insert dna averaging 22.6 kilobase pairs in length. a series of cosmids containing a hydrogen uptake (hup) gene was identified by transferring the gene bank into a h(2) uptake-negative (hup(-)) r. japonicum point mutant (pj17nal) and screening tetracycline-resistant colonies for the ability to grow chemolithotrophica ... | 1983 | 16593268 |
nickel: a micronutrient element for hydrogen-dependent growth of rhizobium japonicum and for expression of urease activity in soybean leaves. | soybean plants and rhizobium japonicum 122 des, a hydrogen uptake-positive strain, were cultured in media purified to remove ni. supplemental ni had no significant effect on the dry matter or total n content of plants. however, the addition of ni to both nitrate-grown and symbiotically grown plants resulted in a 7- to 10-fold increase in urease activity (urea amidohydrolase, ec 3.5.1.5) in leaves and significantly increased the hydrogenase activity (ec 1.18.3.1) in isolated nodule bacteroids. wh ... | 1983 | 16578770 |
mutants of rhizobium japonicum with increased hydrogenase activity. | some strains of rhizobium japonicum can use hydrogen as an energy source for growth under microaerophilic conditions. mutant strains have been selected that use hydrogen in the presence of high partial pressures of oxygen. the mutants contain more hydrogenase than the parent strain, both as free-living cells and as bacteroids in nitrogen-fixing soybean root nodules. | 1983 | 17754553 |
rapid colony screening method for identifying hydrogenase activity in rhizobium japonicum. | a method has been developed for the rapid screening of rhizobium japonicum colonies for hydrogenase activity based on their ability to reduce methylene blue in the presence of respiratory inhibitors and hydrogen. hydrogen uptake-positive (hup) colonies derepressed for hydrogenase activity were visualized by their localized decolorization of filter paper disks impregnated with the dye. appropriate responses were seen with a number of hup and hup wild-type strains of r. japonicum as well as hup mu ... | 1983 | 16346252 |
physiology of ex planta nitrogenase activity in rhizobium japonicum. | thirty-nine wild-type strains of rhizobium japonicum have been studied for their ability to synthesize nitrogenase ex planta in defined liquid media under microaerobic conditions. twenty-one produced more than trace amounts of acetylene reduction activity, but only a few of these yielded high activity. the oxygen response curves were similar for most of the nitrogenase-positive strains. the strains derepressible for activity had several phenotypic characteristics different from non-derepressible ... | 1983 | 16346295 |
evaluation of nitrate reductase activity in rhizobium japonicum. | nitrate reductase activity was evaluated by four approaches, using four strains of rhizobium japonicum and 11 chlorate-resistant mutants of the four strains. it was concluded that in vitro assays with bacteria or bacteroids provide the most simple and reliable assessment of the presence or absence of nitrate reductase. nitrite reductase activity with methyl viologen and dithionite was found, but the enzyme activity does not confound the assay of nitrate reductase. | 1983 | 16346376 |
competition of rhizobium japonicum strains in early stages of soybean nodulation. | the effects of preexposure of soybean (glycine max l. merrill) roots to rhizobium japonicum strains and subsequent establishment of other strains in the nodules were investigated by using combinations of effective strains (usda 110 and usda 138) and effective-ineffective strains (usda 110 and sm-5). strain usda 110 was a better competitor than either usda 138 or sm-5 on cultivars lee and peking. however, when either of the two less-competitive strains was inoculated into 2-day-old seedlings befo ... | 1983 | 16346400 |
possible involvement of a megaplasmid in nodulation of soybeans by fast-growing rhizobia from china. | several isolates from a newly described group of fast-growing acid-producing soybean rhizobia, rhizobium japonicum, were analyzed for plasmid content. all contained from one to four plasmids with molecular weights of 100 x 10 or larger. although most of the isolates shared plasmids of similar size, the restriction endonuclease (bamhi, ecori, and hindiii) patterns of the plasmids from three of the isolates were vastly different. growth in the presence of acridine orange was effective in producing ... | 1983 | 16346403 |
analysis of poly-beta-hydroxybutyrate in rhizobium japonicum bacteroids by ion-exclusion high-pressure liquid chromatography and uv detection. | ion-exclusion high-pressure liquid chromatography (hplc) was used to measure poly-beta-hydroxybutyrate (phb) in rhizobium japonicum bacteroids. the products in the acid digest of phb-containing material were fractionated by hplc on aminex hpx-87h ion-exclusion resin for organic acid analysis. crotonic acid formed from phb during acid digestion was detected by its intense absorbance at 210 nm. the aminex-hplc method provides a rapid and simple chromatographic technique for routine analysis of org ... | 1983 | 16346443 |
high-frequency induction of nodulation and nitrogen fixation mutants of rhizobium japonicum. | more than 50 symbiotic mutants of rhizobium japonicum were isolated by purported plasmid-curing techniques. wild-type r. japonicum strains were grown in liquid culture at 28 or 36 degrees c in different concentrations of acridine orange, ethidium bromide, or sodium dodecyl sulfate for selection of mutants. the symbiotic traits of 133 isolates from nine treatment groups were determined. forty-two isolates were nod- nif+, seven were nod+ nif-, and two were nod- nif-. the nifdh genes were deleted i ... | 1983 | 6630155 |
rna polymerase from rhizobium japonicum. | dna-dependent rna polymerase (ec 2.7.7.6) from rhizobium japonicum was purified. the subunit structure was found to be beta beta' alpha 2 alpha, with the following apparent molecular weights determined by electrophoresis: mr (beta and beta') 150,000 each, mr (sigma) 96,000, mr (alpha) 40,000, mr (holoenzyme) 490,000, mr (core enzyme) 380,000. the recovery of sigma was 28%. rna polymerase from aerobically grown r. japonicum cells and from nitrogen-fixing cells have the same electrophoretic proper ... | 1983 | 6639271 |
compatibility of rhizobium japonicum with commercial pesticides in vitro. | 1983 | 6640140 | |
tryptophan auxotrophs of rhizobium japonicum. | eleven tryptophan-requiring mutants of rhizobium japonicum i-110 ars were isolated after nitrous acid mutagenesis and fell into five groups based on characterization by supplementation with intermediates and enzyme assays. | 1983 | 6643394 |
effects of culture age on symbiotic infectivity of rhizobium japonicum. | the infectivity of the soybean symbiont rhizobium japonicum changed two- to fivefold with culture age for strains 110 ars, 138 str spc, and 123 spc, whereas culture age had relatively little effect on the infectivity of strains 83 str and 61a76 str. infectivity was measured by determining the number of nodules which developed on soybean primary roots in the zone which contained developing and preemergent root hairs at the time of inoculation. root cells in this region of the host root are suscep ... | 1983 | 6681538 |
pleomorphism and acetylene-reducing activity of free-living rhizobia. | cowpea-type rhizobium sp. strain 32h1 and rhizobium japonicum usda 26 and 110 grown on a glutamate-mannitol-gluconate agar medium showed increases in the number of pleomorphic cells coincident with their acetylene-reducing activity. pleomorphs appeared to be inhibited in growth nonuniformly, because acetylene-reducing cultures were mixtures of rod, branched (v, y, and t), and other irregularly shaped cells. in contrast, strain usda 10 consistently failed to reduce acetylene, even though it also ... | 1983 | 6822472 |
a soybean lectin having 4-o-methyl-d-glucuronic acid specificity. | evidence is presented for the presence of a new lectin activity in soybean seeds [glycine max (l.) merrill] that has specificity towards the 4-o-methyl-d-glucurono-l-rhamnan exopolysaccharide produced by certain strains of rhizobium japonicum. bacterial agglutination and precipitin reactions revealed the lectin activity in phosphate-buffered saline extracts of seeds of all cultivars tested, including the "lectinless" varieties. reaction of such extracts with carbohydrate haptens demonstrated tha ... | 1983 | 6838587 |
protoporphyrin formation in rhizobium japonicum. | the obligately aerobic soybean root nodule bacterium rhizobium japonicum produces large amounts of heme (iron protoporphyrin) only under low oxygen tensions, such as exist in the symbiotic root nodule. aerobically incubated suspensions of both laboratory-cultured and symbiotic bacteria (bacteroids) metabolize delta-aminolevulinic acid to uroporphyrin, coproporphyrin, and protoporphyrin. under anaerobic conditions, suspensions of laboratory-cultured bacteria form greatly reduced amounts of protop ... | 1983 | 6841317 |
involvement of cytochromes and a flavoprotein in hydrogen oxidation in rhizobium japonicum bacteroids. | electron transport components involved in h2 oxidation were studied in membranes from rhizobium japonicum bacteroids. hydrogen oxidation in membranes was inhibited by antimycin a and 2-n-heptyl-4-hydroxyquinoline-n-oxide with ki values of 39.4 and 5.6 microm, respectively. the inhibition of h2 uptake by cyanide was triphasic with ki values of 0.8, 9.9, and 93.6 microm. this result suggested that three cyanide-reactive components were involved in h2 oxidation. h2-reduced minus o2-oxidized absorpt ... | 1983 | 6874637 |
nif- hup- mutants of rhizobium japonicum. | two h2 uptake-negative (hup-) rhizobium japonicum mutants were obtained that also lacked symbiotic n2 fixation (acetylene reduction) activity. one of the mutants formed green nodules and was deficient in heme. hydrogen oxidation activity in this mutant could be restored by the addition of heme plus atp to crude extracts. bacteroid extracts from the other mutant strain lacked hydrogenase activity and activity for both of the nitrogenase component proteins. hup+ revertants of the mutant strains re ... | 1983 | 6874648 |
[induced resistance to kanamycin and tetracycline in rhizobium japonicum]. | spontaneous mutants km-r and tc-r of r. japonicum with various levels of resistance to kanamycin (0.8-20 mg/ml) and tetracycline (130-210 micrograms/ml) were isolated. no cross resistance in the mutants was observed. plasmid r68.45 transferred to the wild strains resistance to 210 micrograms/ml of tetracycline and to 20 mg/ml of kanamycin. this plasmid did not practically increase the resistance to tetracycline in mutants tc-r. at the same time it markedly increased the resistance to kanamycin i ... | 1983 | 6881945 |
in rhizobium japonicum the nitrogenase genes nifh and nifdk are separated. | in contrast to klebsiella pneumoniae or fast-growing rhizobium species, such as r. meliloti, where the nitrogenase structural genes are clustered in one operon (nifhdk), in slow-growing rhizobium japonicum 110, nifh and nifdk are on separate operons. | 1983 | 6307985 |
regulation of hydrogenase in rhizobium japonicum: analysis of mutants altered in regulation by carbon substrates and oxygen. | the synthesis of the h2 uptake system in free-living rhizobium japonicum sr is repressed both by oxygen and by carbon substrates. mutants selected for the ability to express hydrogenase in 10.0% partial pressure o2 were also less sensitive than the wild type to repression by carbon substrates such as arabinose, glycerol, gluconate, and succinate. the h2 uptake system in another class of mutants, previously shown to be hypersensitive to repression by o2, is also more sensitive to repression by ca ... | 1983 | 6315681 |
succinate transport by free-living forms of rhizobium japonicum. | we have demonstrated that the transport of succinate into the cells of rhizobium japonicum strains usda 110 and usda 217 is severely inhibited by cyanide, azide, and 2,4-dinitrophenol, but not by arsenate. these results suggest an active mechanism of transport that is dependent on an energized membrane, but does not directly utilize atp. the apparent km for succinate was 3.8 microm for strain usda 110 and 1.8 microm for strain usda 217; maximal transport velocities were 1.5 and 3.3 nmol of succi ... | 1983 | 6402487 |
transfer of nitrate reductase genes of the cyanobacterium nostoc muscorum into rhizobium japonicum. | transformation of rhizobium japonicum cb1809 was studied using dna from the cyanobacterium nostoc muscorum atcc 27893. a spontaneous nitrate reductase deficient (nar-) mutant (nr-6) of r. japonicum cb1809 was isolated with a frequency of 8.4 x 10(-7). streptomycin (sm) and neomycin (neo) resistance markers were introduced into strain nr-6, and the resulting strain was designated nr-6 smr neor. experiments with cyanobacterial dna and live cells of strain nr-6 smr neor indicated transformation of ... | 1983 | 6415231 |
comparative study of the dna-binding hu-type proteins from slow growing and fast growing strains of rhizobiaceae. | the dna-binding hu-type proteins have been isolated from two very different strains of rhizobiaceae : agrobacterium tumefaciens and rhizobium japonicum. these proteins have been called hat and hrj respectively. their electrophoretic mobility on polyacrylamide gel, amino acid composition and crossed immunoreactivity have been compared to that of the homologous protein isolated from rhizobium meliloti: the protein hrm . the proteins hat and hrm show close similarities whereas the protein hrj diffe ... | 1984 | 6428409 |
nickel is a component of hydrogenase in rhizobium japonicum. | the derepression of h2-oxidizing activity in free-living rhizobium japonicum does not require the addition of exogenous metal to the derepression media. however, the addition of edta (6 microm) inhibited derepression of h2 uptake activity by 80%. the addition of 5 microm nickel to the derepression medium overcame the edta inhibition. the addition of 5 microm cu or zn also relieved edta inhibition, but to a much lesser extent; 5 microm fe, co, mg, or mn did not. the kinetics of induction and magn ... | 1984 | 6429119 |
bacteriophage that can distinguish between wild-type rhizobium japonicum and a non-nodulating mutant. | a bacteriophage (phage tn1) that lyses rhizobium japonicum 3i1b110 was isolated from tennessee soil. structurally, this phage resembles the escherichia coli phage t4, having an icosahedral head (47 by 60 nm) and a contractile tail (17 by 80 nm). an interesting feature of this phage is that it lyses all of the symbiotic defective mutants derived from r. japonicum 3i1b110 that were tested, except one, mutant strain hs123. mutant strain hs123 is a non-nodulating mutant that is defective in attachme ... | 1984 | 6476831 |
role of rhizobitoxine in protecting soybean roots from macrophomina phaseolina infection. | bacterization of soybean seeds or roots with rhizobium japonicum significantly reduced charcoal rot disease caused by macrophomina phaseolina . rhizobium japonicum inhibited the growth of m. phaseolina on both liquid and solid media. replacement of nutrient medium with culture filtrate of r. japonicum significantly reduced mycelial growth of m. phaseolina . whole culture extracts of r. japonicum yielded a toxic substance which was identified as rhizobitoxine after chromatographic, ultraviolet, a ... | 1984 | 6539157 |
mode of infection, nodulation specificity, and indigenous plasmids of 11 fast-growing rhizobium japonicum strains. | eleven fast-growing strains of rhizobium japonicum were characterized with respect to indigenous plasmids and abilities to infect (inf+) and nodulate (nod+) cowpea, siratro, wild soybean, and three commercial cultivars of soybean. all strains caused infection via infection threads in root hairs and consistently nodulated cowpea, siratro, and wild soybean in growth pouches. interactions with commercial cultivars of soybean were strikingly strain specific. some combinations were nod-, and infectio ... | 1984 | 6542099 |
extracellular polysaccharide composition, ex planta nitrogenase activity, and dna homology in rhizobium japonicum. | the composition of the major acidic extracellular polysaccharide (eps) of 25 strains of rhizobium japonicum was determined. eight strains synthesized an acidic eps containing rhamnose and 4-o- methylglucuronic acid and were closely related according to dna homology. these same strains also expressed high levels of ex planta nitrogenase activity. sixteen strains produced an acidic eps containing glucose, mannose, galacturonic acid, and galactose and were also related by dna homology. these strain ... | 1984 | 6586714 |
the nifh and nifdk promoter regions from rhizobium japonicum share structural homologies with each other and with nitrogen-regulated promoters from other organisms. | in several species of rhizobium the three genes which encode the nitrogenase complex are separated into two operons, nifh and nifdk. we have mapped the transcriptional promoter sites for these two operons from r. japonicum usda strain 110 by s1 protection analyses using bacterial rna isolated from soybean nodules. transcription of the nifdk operon is initiated at a site located 46 nucleotides upstream of the proposed translation initiation codon. nifh transcription initiates predominantly at a s ... | 1984 | 6588133 |
rhizobium japonicum nitrogenase fe protein gene (nifh). | a 12.1-kilobase psti fragment from rhizobium japonicum, which contains homology to both the klebsiella pneumoniae and the rhizobium meliloti nifh genes, was cloned into vector phe3 . the nifh -homologous region was localized on the restriction enzyme cleavage map by southern blot hybridization experiments. dna fragments overlapping the r. japonicum nifh gene were subcloned into plasmid vectors to allow the expression of this region in escherichia coli minicells. the nifh gene product (the polype ... | 1984 | 6327620 |
isolation and expression of rhizobium japonicum cloned dna encoding an early soybean nodulation function. | a first visible step in the nodulation of legumes by rhizobium spp. is the deformation and curling of root hairs. we have identified and cloned dna sequences encoding this function from two strains of rhizobium japonicum (usda 122 and usda 110) with a weakly homologous probe from rhizobium meliloti. root hair curling encoded by the cloned dna fragments was examined on soybeans (glycine soja ) after conjugative transfer of these sequences in broad-host-range vectors to various bacterial genera. p ... | 1984 | 6327649 |
transposon tn5-induced mutagenesis of rhizobium japonicum yielding a wide variety of mutants. | when the "suicide" vector psup1011, which carries transposon tn5 (kmr), was introduced into rhizobium japonicum usda 110, kanamycin-resistant (kmr) colonies were detected at a frequency (4.2 x 10-6) ca. 30 times greater than the spontaneous kanamycin resistance frequency (1.4 x 10-7). ten thousand kmr mutants were isolated and tested for nutritional auxotrophy. auxotrophs were detected at a frequency of 0.5%. the following classes of auxotrophs were identified: adenine- (three), histidine- (thre ... | 1984 | 6330038 |
induced plasmid-genome rearrangements in rhizobium japonicum. | the p group resistance plasmids rp1 and rp4 were introduced into rhizobium japonicum by polyethylene-glycol-induced transformation of spheroplasts. after cell wall regeneration, transformants were recovered by selecting for plasmid determinants. plant nodulation, nitrogen fixation, serological, and bacterial genetics studies revealed that the transformants were derived from the parental strains and possessed the introduced plasmid genetic markers. agarose gel electrophoresis, restriction enzyme ... | 1984 | 6360996 |
preservation of rhizobium viability and symbiotic infectivity by suspension in water. | three rhizobium japonicum strains and two slow-growing cowpea-type rhizobium strains were found to remain viable and able to rapidly modulate their respective hosts after being stored in purified water at ambient temperatures for periods of 1 year and longer. three fast-growing rhizobium species did not remain viable under the same water storage conditions. after dilution of slow-growing rhizobium strains with water to 10(3) to 10(5) cells ml-1, the bacteria multiplied until the viable cell coun ... | 1984 | 6378090 |
some properties of the nickel-containing hydrogenase of chemolithotrophically grown rhizobium japonicum. | the uptake hydrogenase of chemolithotrophically grown rhizobium japonicum was purified to apparent homogeneity with a final specific activity of 69 mumol of h2 oxidized per min per mg of protein. the procedure included triton extraction of broken membranes and deae-cellulose and sephacryl s-200 chromatographies. the purified protein contained two polypeptides separable only by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. they comigrated on native polyacrylamide gels and sucrose den ... | 1984 | 6384183 |
coordinate expression of hydrogenase and ribulose bisphosphate carboxylase in rhizobium japonicum hupc mutants. | in contrast to the wild type, h2 uptake-constitutive mutants of rhizobium japonicum expressed both hydrogenase and ribulose bisphosphate carboxylase activities when grown heterotrophically. however, as bacteroids from soybean root nodules, the h2 uptake-constitutive mutants, like the wild type, did not express ribulose bisphosphate carboxylase activity. | 1984 | 6384199 |
evaluation of active versus passive uptake of metabolites by rhizobium japonicum bacteroids. | rhizobium japonicum bacteroids were isolated anaerobically from soybean [glycine max (l.) merr] nodules. the bacteroids, which were capable of acetylene reduction and respiration, were used to study the uptake of metabolites by a method which permits correction for nonspecific adsorption of metabolites and estimation of total cell volume. these determinations permit active uptake to be assessed from metabolite accumulation against a concentration gradient. succinate, malate, alpha-ketoglutarate, ... | 1984 | 6203891 |
characterization of rhizobium japonicum hydrogen uptake genes. | recombinant cosmids from a gene library of the dna from hup+ rhizobium japonicum 122des previously have been shown to restore hydrogenase activity when transferred by conjugation into certain hup- mutants of r. japonicum. we generated a restriction map covering 32.2 kilobases of this cosmid dna. at least 25.3 kilobases of the cosmid phu1 were shown to have the same arrangement as those in the genome of strain 122des. analysis of tn5 insertions into the 122des genome indicates that hup-specific s ... | 1984 | 6090382 |
isolation and expression of the bradyrhizobium japonicum adenylate cyclase gene (cya) in escherichia coli. | a 5.0-kilobase-pair hindiii fragment of bradyrhizobium japonicum dna containing the cya gene which encodes adenylate cyclase was isolated as an insert in pbr322, using marker rescue of the maltose-negative phenotype of an escherichia coli cya mutant for identification. the isolated b. japonicum dna fragment was capable of reversing the pleiotropic phenotype of cya mutations when inserted in either orientation in the hindiii site of pbr322. the complemented e. coli strains produced high levels of ... | 1984 | 6090388 |
physical organization of the bradyrhizobium japonicum nitrogenase gene region. | in bradyrhizobium japonicum usda 110 the three genes that encode the nitrogenase enzyme complex are separated into two transcription units, nifh and nifdk. we have physically mapped a 33-kilobase-pair region of the b. japonicum genome that contains both nifh and nifdk. the nifdk operon is located transcriptionally upstream from nifh, and all three genes are transcribed in the same direction. within the 20-kilobase-pair region that separates the promoters for these two transcription units, we hav ... | 1984 | 6090394 |
reiteration of genes involved in symbiotic nitrogen fixation by fast-growing rhizobium japonicum. | by using cloned rhizobium meliloti nodulation (nod) genes and nitrogen fixation (nif) genes, we found that the genes for both nodulation and nitrogen fixation were on a plasmid present in fast-growing rhizobium japonicum strains. two ecori restriction fragments from a plasmid of fast-growing r. japonicum hybridized with nif structural genes of r. meliloti, and three ecori restriction fragments hybridized with the nod clone of r. meliloti. cross-hybridization between the hybridizing fragments rev ... | 1984 | 6094491 |
mineral soils as carriers for rhizobium inoculants. | mineral soil-based inoculants of rhizobium meliloti and rhizobium phaseoli survived better at 4 degrees c than at higher temperatures, but ca. 15% of the cells were viable at 37 degrees c after 27 days. soil-based inoculants of r. meliloti, r. phaseoli, rhizobium japonicum, and a cowpea rhizobium sp. applied to seeds of their host legumes also survived better at low temperatures, but the percent survival of such inoculants was higher than peat-based inoculants at 35 degrees c. survival of r. pha ... | 1984 | 16346460 |
rhizosphere response as a factor in competition among three serogroups of indigenous rhizobium japonicum for nodulation of field-grown soybeans. | rhizosphere response was studied as a factor in competition among indigenous rhizobium japonicum serogroups for the nodulation of soybeans under field conditions. r. japonicum serogroups 110, 123, and 138 were found to coexist in a waukegan field soil where they were determined to be the major nodulating rhizobia in soybean nodules. competitive relationships among the three serogroups in that soil and in rhizospheres were examined during two growing seasons with several host cultivars with and w ... | 1984 | 16346501 |
rhizobium japonicum serogroup and hydrogenase phenotype distribution in 12 states. | a survey was conducted in 1980 on 972 isolates of rhizobium japonicum obtained from 65 soybean field locations in 12 states. isolates were examined for the hydrogenase (hup) phenotype and somatic serogroup identity. only 20% of the isolates were hup, with a majority of hup isolates occurring in 10 of the 12 states. the most predominant serogroup was 31 (21.5%), followed by 123 (13.6%). although most serogroups contained a majority of hup isolates, marked differences occurred. none of the isolate ... | 1984 | 16346502 |
invalidity of the concept of slow growth and alkali production in cowpea rhizobia. | a total of 103 rhizobial strains representing the cowpea miscellany and rhizobium japonicum were studied with regard to growth rate, glucose metabolic pathways, and ph change in culture medium. doubling times ranged from 1.4 +/- 0.04 to 44.1 +/- 5.2 h; although two populations of "fast-growing" and "slow-growing" rhizobia were noted, they overlapped and were not distinctly separated. twenty-four strains which had doubling times of less than 8 h all showed nadp-linked 6-phosphogluconate dehydroge ... | 1984 | 16346589 |
fast-growing rhizobium japonicum that effectively nodulates several commercial glycine max l. merrill cultivars. | several isolates of fast-growing rhizobium japonicum that nodulate the wild soybean glycine soja have been recently described (keyser et al., science 215:1631-1632, 1982). we demonstrate that one of these isolates, designated prc 440 or usda 191, has a wider host range than that previously reported and is able to nodulate several commercial glycine max cultivars as effectively as does slow-growing r. japonicum 61a76. electron microscopic examination revealed no obvious differences between strain ... | 1984 | 16346594 |
nitrogen fixation and carbon dioxide assimilation in rhizobium japonicum. | in free-living rhizobium japonicum cultures, the stimulatory effect of co(2) on nitrogenase (acetylene reduction) activity was mediated through ribulose bisphosphate carboxylase activity. two mutant strains (cj5 and cj6) of r. japonicum defective in co(2) fixation were isolated by mitomycin c treatment. no ribulose bisphosphate carboxylase activity could be detected in strain cj6, but a low level of enzyme activity was present in strain cj5. mutant strain cj5 also exhibited pleiotropic effects o ... | 1984 | 16346608 |
enhancing soybean rhizosphere colonization by rhizobium japonicum. | a study was conducted to seek means to increase the colonization of the rhizosphere of soybeans (glycine max l. merrill) by rhizobium japonicum. for this purpose, a strain of r. japonicum that was resistant to benomyl, streptomycin, and erythromycin was used. the numbers of r. japonicum rose quickly in the first 2 days after soybean seeds were planted in soil and then rapidly fell. the decline was slower if the seeds were coated with benomyl. this fungicide reduced the numbers of bacteria and pr ... | 1984 | 16346616 |
nodulation of soybeans as affected by half-root infection with heterodera glycines. | a split-root technique was applied to soybean, glycine max (l.) merr. cv. lee 68, to characterize the nature of the nodulation suppression by race 1 of the soybean cyst nematode (scn), heterodera glycines. root-halves of each split-root plant were inoculated with rhizobium japonicum, and one root-half only was inoculated with various numbers of scn eggs. nodulation (indicated by nodule number, nodule weights, and ratio of nodule weight to root weight) and nitrogen-fixing capacity (indicated by r ... | 1984 | 19295882 |
expression of beta-galactosidase controlled by a nitrogenase promoter in stem nodules of aeschynomene scabra. | a 365-base-pair (bp) dna fragment, containing the promoter region of the nitrogenase reductase (nifh) gene from stem rhizobium btai1, has been isolated and sequenced. the transcription initiation sites were localized at positions 152 (major initiation) and 114 (minor initiation) nucleotides upstream of the translation initiation codon. the 200-bp nucleotide sequence upstream of the nifh structural gene shows substantial homology to the corresponding nifh regions of cowpea rhizobium (100%), paras ... | 1984 | 16593514 |
cloned avirulence gene of pseudomonas syringae pv. glycinea determines race-specific incompatibility on glycine max (l.) merr. | a genomic library of pseudomonas syringae pv. glycinea race 6 dna was constructed in the mobilizable cosmid vector plafr1 and maintained in escherichia coli hb101. completeness of the library was estimated by assaying clones for the expression of ice-nucleating activity in e. coli. ice-nucleation activity was represented approximately once in every 600 clones. six hundred eighty random race 6 cosmid clones were mobilized from e. coli by plasmid prk2013 in individual conjugations to a race 5 stra ... | 1984 | 16593517 |
effect of salinity on nodule formation by soybean. | a split-root growth system was employed to evaluate the effect of nacl on nodule formation by soybean (glycine max l. merr. cv davis). by applying the salinity stress and rhizobial inoculum to only one-half the root system, the effects of salinity on shoot growth were eliminated in the nodulation process. rhizobium colonization of inoculated root surfaces was not affected by the salt treatments (0.0, 26.6, 53.2, and 79.9 millimolar nacl). while shoot dry weight remained unaffected by the treatme ... | 1984 | 16663389 |
role of lectins in the specific recognition of rhizobium by lotononis bainesii. | fluorescein isothiocyanate (fitc)-labeled lectin purified from the root of lotononis bainesii baker was bound by cells of five out of seven l. bainesii-nodulating strains of rhizobium under culture conditions. with the exception of a strain of rhizobium leguminosarum, strains of noninfective rhizobia failed to bind the root lectin under these conditions. the two nonlectin binding l. bainesii-specific strains did not bind root lectin on the l. bainesii rhizoplane although this was observed with t ... | 1984 | 16663509 |
suppression of nodule development of one side of a split-root system of soybeans caused by prior inoculation of the other side. | in a split-root system of soybeans (glycine max l. merr), inoculation of one half-side suppressed subsequent development of nodules on the opposite side. at zero time, the first side of the split-root system of soybeans received rhizobium japonicum strain usda 138 as the primary inoculum. at selected time intervals, the second side was inoculated with the secondary inoculum, a mixture of r. japonicum strain usda 138 and strain usda 110. in a short-day season, nodulation by the secondary inoculum ... | 1984 | 16663555 |
enzymes of the poly-beta-hydroxybutyrate and citric acid cycles of rhizobium japonicum bacteroids. | the activities of several enzymes of the citric acid and poly-beta-hydroxybutyrate cycles were measured in rhizobium japonicum 3i1b-143 bacteroids which had been isolated from soybean nodules by sucrose gradient centrifugation. during the period of developing nitrogenase activity, the specific activity of fumarase, hydroxybutyrate dehydrogenase, beta-ketothiolase, and pyruvate dehydrogenase complex increased whereas acetoacetate-succinyl-coa transferase and isocitrate dehydrogenase decreased. ma ... | 1984 | 16663750 |
lysis of bacterioids in the vicinity of the host cell nucleus in an ineffective (fix(-)) root nodule of soybean (glycine max). | in nodules of glycine max cv. mandarin infected with a nod (+)fix(-) mutant of rhizobium japonicum (rh 31-marburg), lysis of bacteroids was observed 20 d after infection, but occurred in the region around the host cell nucleus, where lytic compartments were formed. bacteroids, and peribacteroid membranes in other parts of the host cell remained stable until senescence (40d after infection). with two other nod(+) fix(-) mutants of r. japonicum either stable bacteroids and peribacteroid membranes ... | 1984 | 24253941 |
insertion and deletion mutations within the nif region of rhizobium japonicum. | insertion and deletion mutants were used to characterize a genomic region of rhizobium japonicum where the nitrogenase structural genes are located on two separate operons nifdk and nifh. in addition to previously described nifd:: tn5 and nifk:: tn5 mutations we have now generated, by localized mutagenesis, further tn5 insertion mutations in the vicinity of nifdk as well as within and adjacent to nifh. the nifd:: tn5, nifk:: tn5, and nifh:: tn5 mutant strains were of the nod(+) fix(-) phenotype ... | 1984 | 24310349 |
spatial relationships between uninfected and infected cells in root nodules of soybean. | in soybean (glycine max (l.) merr.) the uninfected cells of the root nodule are responsible for the final steps in ureide production from recently fixed nitrogen. stereological methods and an original quantitative method were used to investigate the organization of these cells and their spatial relationships to infected cells in the central region of nodules of soybean inoculated with rhizobium japonicum strain usda 3i1b110 and grown with and without nitrogen (as nitrate) in the nutrient medium. ... | 1985 | 24241217 |
ultrastructure of infection-thread development during the infection of soybean by rhizobium japonicum. | the location and topography of infection sites in soybean (glycine max (l.) merr.) root hairs spot-inoculated with rhizobium japonicum have been studied at the ultrastructural level. infections commonly developed at sites created when the induced deformation of an emerging root hair caused a portion of the root-hair cell wall to press against an adjacent epidermal cell, entrapping rhizobia within the pocket between the two host cells. infections were initiated by bacteria which became embedded i ... | 1985 | 24249405 |
relationship between ureide n and n(2) fixation, aboveground n accumulation, acetylene reduction, and nodule mass in greenhouse and field studies with glycine max l. (merr). | the relationship between ureide n and n(2) fixation was evaluated in greenhouse-grown soybean (glycine max l. merr.) and lima bean (phaseolus lunatus l.) and in field studies with soybean. in the greenhouse, plant n accumulation from n(2) fixation in soybean and lima bean correlated with ureide n. in soybean, n(2) fixation, ureide n, acetylene reduction, and nodule mass were correlated when n(2) fixation was inhibited by applying kno(3) solutions to the plants. the ureide-n concentrations of dif ... | 1985 | 16664027 |
nitrate inhibition of legume nodule growth and activity : i. long term studies with a continuous supply of nitrate. | the synthesis and accumulation of nitrite has been suggested as a causative factor in the inhibition of legume nodules supplied with nitrate. plants were grown in sand culture with a moderate level of nitrate (2.1 to 6.4 millimolar) supplied continuously from seed germination to 30 to 50 days after planting. in a comparison of nitrate treatments, a highly significant negative correlation between nitrite concentration in soybean (glycine max [l.] merr.) nodules and nodule fresh weight per shoot d ... | 1985 | 16664051 |
nitrate inhibition of legume nodule growth and activity : ii. short term studies with high nitrate supply. | soybean plants (glycine max [l.] merr) were grown in sand culture with 2 millimolar nitrate for 37 days and then supplied with 15 millimolar nitrate for 7 days. control plants received 2 millimolar nitrate and 13 millimolar chloride and, after the 7-day treatment period, all plants were supplied with nil nitrate. the temporary treatment with high nitrate inhibited nitrogenase (acetylene reduction) activity by 80% whether or not rhizobium japonicum bacteroids had nitrate reductase (nr) activity. ... | 1985 | 16664052 |
host recognition in the rhizobium-soybean symbiosis : evidence for the involvement of lectin in nodulation. | rhizobium japonicum mutant strain hs111 was previously shown to be defective in the rate of initiation of infection leading to subsequent nodule formation (1984 plant physiol 74: 84-89). mutant strain hs111's defect in nodulation can be phenotypically reversed to wild type levels by pretreatment with root exudates from all soybean varieties that have been tested. the data indicate that lectin-rhizobium interaction is necessary for the phenotypic reversal of the nodulation characteristics of muta ... | 1985 | 16664109 |
a supernodulation and nitrate-tolerant symbiotic (nts) soybean mutant. | the nodulation characteristics of soybean (glycine max) mutant nts382 are described. the mutant nodulated significantly more than the parent cultivar bragg in the presence and absence of several combined nitrogen sources (kno(3), urea, nh(4)cl, and nh(4)no(3)). the number of nodules on the tap root and on lateral roots was increased in the mutant line. in the presence of kno(3) and urea, nitrogenase activity was considerably higher in nts382 than in bragg. mutant plants were generally smaller th ... | 1985 | 16664203 |
decreased exopolysaccharide synthesis by anaerobic and symbiotic cells of bradyrhizobium japonicum. | experiments were conducted to determine whether symbiotic bacteroids of bradyrhizobium japonicum produce exopolysaccharide within soybean (glycine max [l.] merr. cv ;lee 74') nodules. b. japonicum strains rt2, a derivative of usda 110 with resistance to streptomycin and rifampicin, and rt176-1, a mutant deficient in exopolysaccharide synthesis, were used. although aerobically cultured rt2 produced 1550 micrograms of exopolysaccharide per 10(10) cells, root nodules formed by rt2 contained only 55 ... | 1985 | 16664430 |
glycine-glomus-rhizobium symbiosis: ii. antagonistic effects between mycorrhizal colonization and nodulation. | soybean (glycine max [l.] merr.) plants grown in pot cultures were inoculated with the vesicular-arbuscular mycorrhizal (vam) fungus glomus mosseae (nicol. & gerd.) gerd. and trappe and rhizobium japonicum strain 61a118 at planting (g(1)r(1)) or at 20 days (g(20)r(20)), or with one of the endophytes after the other has colonized the host root (g(1)r(20), g(20)r(1)). nodulated (pr(1)) and vam (g(1)n) dipartite associations, or nonsymbiotic plants (pn) using nutrient solutions with n, p, or n + p ... | 1985 | 16664528 |
intra- and interspecies transfer and expression of rhizobium japonicum hydrogen uptake genes and autotrophic growth capability. | cosmids containing hydrogen uptake genes have previously been isolated in this laboratory. four new cosmids that contain additional hup gene(s) have now been identified by conjugal transfer of a rhizobium japonicum 122des gene bank into a tn5-generated hup(-) mutant and screening for the acquisition of hup activity. the newly isolated cosmids, phu50-phu53, contain part of the previously isolated phu1 but extend as far as 20 kilobases beyond its border. phu52 complements five of six hup(-) mutant ... | 1985 | 16578786 |
effectiveness of rhizobium strains used in inoculants after their introduction into soil. | rhizobium strains used in inoculants for trifolium spp., medicago spp., glycine max, and lotus pedunculatus were isolated from nodules of these legumes grown in soils into which the rhizobia had been introduced 4 to 8 years before. isolations were made from a total of 420 nodules. nodule occupancy by the inoculant strains varied from 17.7% for a soybean strain to 100% in the case of l. pedunculatus whose specific rhizobia did not occur in the soils studied. in general, inoculant strains isolated ... | 1985 | 16346692 |
simplified enzyme-linked immunosorbent assay for routine identification of rhizobium japonicum antigens. | a simple, reliable, and flexible modification of the indirect enzyme-linked immunosorbent assay was developed for the identification of rhizobium japonicum antigens from cultures and nodules. the procedure emphasizes efficient use of time and reagents, adaptability to variously equipped laboratories, and maintenance of sensitivity levels that are adequate for ecological studies. | 1985 | 16346765 |
anaerobic growth and denitrification among different serogroups of soybean rhizobia. | we screened soybean rhizobia originating from three germplasm collections for the ability to grow anaerobically in the presence of no(3) and for differences in final product formation from anaerobic no(3) metabolism. denitrification abilities of selected strains as free-living bacteria and as bacteroids were compared. anaerobic growth in the presence of no(3) was observed in 270 of 321 strains of soybean rhizobia. all strains belonging to the 135 serogroup did not grow anaerobically in the prese ... | 1985 | 16346767 |
influence of environmental factors on interstrain competition in rhizobium japonicum. | the effect of several biotic and abiotic factors on the pattern of competition between two strains of rhizobium japonicum was examined. in two minnesota soils, waseca and waukegan, strain usda 123 occupied 69% (waseca) and 24% (waukegan) of the root nodules on glycine max l. merrill cv. chippewa. usda 110 occupied 2% of the root nodules in the waseca soil and 12% of the nodules in the waukegan soil. under a variety of other growth conditions-vermiculite, vermiculite amended with waseca soil, and ... | 1985 | 16346786 |
determination of the hydrogenase status of individual legume nodules by a methylene blue reduction assay. | we adapted a method for the rapid screening of colonies of free-living rhizobium japonicum for hydrogenase activity to determine the hydrogenase status of individual soybean nodules. crude bacteroid suspensions from nodules containing strains known to be hydrogen uptake positive (hup) caused a localized decolorization of filter paper disks, whereas suspensions from nodules arising from inoculation with hydrogen uptake-negative (hup) mutants or strains did not decolorize the disks. the reliabilit ... | 1985 | 16346869 |
predominance of fast-growing rhizobium japonicum in a soybean field in the people's republic of china. | soybean rhizobia were isolated from two soils with different cropping histories from hubei province in central china. the first, from honghu county, has been under soybean cultivation for decades. all of the isolates obtained from nodules on soybeans growing in this soil were fast-growing, acid-producing rhizobia. however, slow-growing, alkali-producing isolates were obtained at higher dilutions of the same soil. the second soil, from wuchang county, has been under rice cultivation with no recor ... | 1985 | 16346926 |
isolation of genes (nif/hup cosmids) involved in hydrogenase and nitrogenase activities in rhizobium japonicum. | recombinant cosmids containing a rhizobium japonicum gene involved in both hydrogenase (hup) and nitrogenase (nif) activities were isolated. an r. japonicum gene bank utilizing broad-host-range cosmid plafr1 was conjugated into hup- nif- r. japonicum strain sr139. transconjugants containing the nif/hup cosmid were identified by their resistance to tetracycline (tcr) and ability to grow chemoautotrophically (aut+) with hydrogen. all tcr aut+ transconjugants possessed high levels of h2 uptake acti ... | 1985 | 3882669 |
further evidence that two unique subunits are essential for expression of hydrogenase activity in rhizobium japonicum. | eight strains of rhizobium lacking hydrogenase uptake (hup) activity and 17 transconjugant strains carrying the hup cosmids phu1, phu52, or phu53 (g. r. lambert, m. a. cantrell, f. j. hanus, s. a. russell, k. r. haddad, and h. j. evans, proc. natl. acad. sci. usa, 82:3232-3236, 1985) were screened for hup activity and the presence of immunologically detectable hydrogenase polypeptides. crude extracts of these strains were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and ... | 1985 | 3900036 |
rhizobium japonicum hydrogenase: purification to homogeneity from soybean nodules, and molecular characterization. | rhizobium japonicum hydrogenase was purified to homogeneity from soybean root nodules by four column chromatography steps after solubilization from membranes by treatment with a nonionic detergent. the specific activity was from 40 to 65 mumol h2 oxidized min-1 mg protein-1 and was increased 450-fold relative to that in bacteroids. the yield of activity was from 7 to 12%. the molecular weight of the native enzyme was 104,000 as determined by sucrose density gradient centrifugation. electrophores ... | 1985 | 3919648 |
nitric oxide-dependent proton translocation in various denitrifiers. | respiration of no resulted in transient proton translocation in anaerobically grown cells of four physiologically diverse denitrifiers. paracoccus denitrificans, rhodopseudomonas sphaeroides subsp. denitrificans, "achromobacter cycloclastes," and rhizobium japonicum gave, respectively, h+/no ratios of 3.65, 4.96, 1.94, and 1.12. antimycin a completely inhibited no-dependent proton translocation in p. denitrificans and severely restricted translocation in the r. sphaeroides strain. proton uptake ... | 1985 | 3928599 |
production of monoclonal antibodies in culture. | factors that affected the production of monoclonal antibodies by a mouse-mouse hybridoma cell line, propagated in vitro in stirred vessels, were investigated. the purpose of the research was to estimate the efficiency of this system for large scale production of monoclonal antibodies. the antibody produced by these hybridoma cells was an igg2a, specific for a surface antigen on rhizobium japonicum nr-7 cells. antibody content in the culture supernatant was determined by a radial-immunodiffusion ... | 1985 | 3930316 |
expression of cytochrome o in hydrogen uptake constitutive mutants of rhizobium japonicum. | mutant strains of rhizobium japonicum constitutive for h2 uptake activity (hupc) contained significantly more membrane-bound b-type cytochrome than did the wild type when grown heterotrophically. the hupc strains contained approximately three times more dithionite- and nadh-reducible co-reactive b-type cytochrome than did the wild type; the absorption features of the co spectra were characteristic of cytochrome o. this component, designated cytochrome b', was not reduced by nadh in the presence ... | 1985 | 3968033 |
role of ubiquinone in hydrogen-dependent electron transport in rhizobium japonicum. | direct evidence for the involvement of ubiquinone in h2 oxidation by rhizobium japonicum was demonstrated; h2 reduced ca. 80% of the extractable ubiquinone. the inhibitor 2-n-heptyl-4-hydroxyquinoline-n-oxide blocked electron transport at a site between ubiquinone and the cytochromes. the results showed that no cytochrome component mediates electron flow from hydrogen to ubiquinone. | 1985 | 3968040 |
molecular and immunological comparison of membrane-bound, h2-oxidizing hydrogenases of bradyrhizobium japonicum, alcaligenes eutrophus, alcaligenes latus, and azotobacter vinelandii. | the membrane-bound hydrogenases of bradyrhizobium japonicum, alcaligenes eutrophus, alcaligenes latus, and azotobacter vinelandii were purified extensively and compared. sodium dodecyl sulfate-polyacrylamide gel electrophoresis of each hydrogenase revealed two prominent protein bands, one near 60 kilodaltons and the other near 30 kilodaltons. the migration distances during nondenaturing polyacrylamide gel electrophoresis were similar for all except a. vinelandii hydrogenase, which migrated furth ... | 1985 | 4008438 |
conservation of symbiotic nitrogen fixation gene sequences in rhizobium japonicum and bradyrhizobium japonicum. | southern hybridization with nif (nitrogen fixation) and nod (nodulation) dna probes from rhizobium meliloti against intact plasmid dna of rhizobium japonicum and bradyrhizobium japonicum strains indicated that both nif and nod sequences are on plasmid dna in most r. japonicum strains. an exception is found with r. japonicum strain usda194 and all b. japonicum strains where nif and nod sequences are on the chromosome. in r. japonicum strains, with the exception of strain usda205, both nif and nod ... | 1985 | 4008441 |