Publications

mass spectrometric quantification of indole-3-acetic acid in rhizobium culture supernatants: relation to root hair curling and nodule initiation.	indole-3-acetic acid (iaa) has been unequivocally identified in culture supernatants of rhizobium strains by gas chromatography-mass spectrometry. a method for accurately quantitating iaa in bacterial culture supernatants, employing deuterium-labeled iaa as an internal standard, has been developed. similar iaa concentrations were found in culture supernatants of chosen rhizobium mutants (defective in nodule formation) and their corresponding parent strains. since some of the mutants are known to ...	1982	16346073
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
alteration of the trifoliin a-binding capsule of rhizobium trifolii 0403 by enzymes released from clover roots.	the effect of white clover root exudate on capsules of rhizobium trifolii 0403 was examined. the clover lectin trifoliin a was detected in root exudate of two clover varieties by indirect immunofluorescence with antibody against this lectin purified from clover seed. trifoliin a bound uniformly to encapsulated, heat-fixed cells during 1 h of incubation with root exudate. after 4 to 8 h of incubation, trifoliin a was only bound to one pole of the cells. transmission electron microscopy showed tha ...	1982	16346081
quantitative study of nodulation competitiveness in rhizobium strains.	we compared the nodulation competitiveness of three strains of rhizobium leguminosarum by counting the number of nodules formed on faba bean plants after the application at sowing time of different concentrations of the strains to soils already containing rhizobium strains of the same species. a relationship of type y = ax was found to exist between the ratio of the nodules formed by the applied inoculum strain to the nodules formed by the soil strains and the ratio of rhizobium cells in the ino ...	1982	16346089
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
effect of salinity on rhizobium growth and survival.	this study examines the effect of salinity on the growth and survival of rhizobium spp. in culture media and soil. eleven isolates from saline and nonsaline environments were compared. the growth (mean doubling time) of all strains and species tested decreased when the electrical conductivity of the culture medium (yeast extract-mannitol) was raised from 1.2 ms cm to 6.7 ms cm (15% seawater equivalent) or to 13.1 ms cm (28% seawater equivalent). three of eleven strains failed to grow at 13.1 ms ...	1982	16346113
nodulation of pole bean (phaseolus vulgaris l.) by rhizobium species of two cross-inoculation groups.	physiology and morphology of pole bean (phaseolus vulgaris l. cv kentucky wonder) root nodules induced by two rhizobium species of different cross-inoculation groups have been compared. root nodules induced by rhizobium sp. 127e15, which is a strain of the cowpea group rhizobium, were pinkish, had irregular shapes, and were only partially effective. their peak acetylene reduction activity was 4.36 mumol of c(2)h(4) formed per g of fresh nodules per h at 30 days after inoculation. the effective n ...	1982	16346121
competitiveness of rhizobium trifolii strains associated with red clover (trifolium pratense l.) in mississippi soils.	five strains of rhizobium trifolii were evaluated in competition with indigenous populations in nodulating red clover (trifolium pratense l.) cv. kenland in two different soils in mississippi. double antibiotic resistance acquisition was used to measure the proportion of nodules occupied by the introduced mutant strains. in vertisol soil, strains rp113-7, 162bb1, lm1, and 162p17 were recovered in at least 94% of the assayed nodules, whereas ta1 was found in 83.8% of the nodules. at an ultisol lo ...	1982	16346130
comparison of the pour, spread, and drop plate methods for enumeration of rhizobium spp. in inoculants made from presterilized peat.	inoculants prepared with presterilized peat were enumerated by the pour, spread, and drop plate techniques. results indicated that the three plating methods were interchangeable. the drop plate method was preferred because of its economy in materials and labor.	1982	16346141
recognition of leguminous hosts by a promiscuous rhizobium strain.	the lima bean (phaseolus lunatus l.) and the pole bean (phaseolus vulgaris l.) are nodulated by rhizobia of two different cross-inoculation groups. rhizobium sp. 127e15, a cowpea-type rhizobium, can induce effective nodules on the lima bean and partially effective nodules on the pole bean. rhizobium phaseoli 127k14 can induce effective nodules on the pole bean but does not reciprocally nodulate the lima bean. root hairs of the lima bean when inoculated with rhizobium sp. 127e15 showed tip curlin ...	1982	16345975
genetic analysis of nitrogen fixation in a tropical fast-growing rhizobium.	the rhizobium strain ors571, which is associated with the tropical legume sesbania rostrata, has the property of growing in the free-living state at the expense of ammonia or n(2) as sole nitrogen source. five mutants, isolated as unable to form colonies on plates under conditions of nitrogen fixation, were studied. all of them, which appear as fixin planta, are nif mutants. with mutant 5740, nitrogenase activity of the crude extract was restored by addition of pure mo-fe protein of klebsiella p ...	1982	16453420
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
interactions between nitrogen fixation, mycorrhizal colonization, and host-plant growth in the phaseolus-rhizobium-glomus symbiosis.	bean (phaseolus vulgaris l. cv. dwarf) roots were inoculated with rhizobium phaseoli and colonized by the vesicular-arbuscular mycorrhizal (vam) fungus glomus fasciculatum gerd. and trappe or left uncolonized as controls. the symbiotic associations were grown in an inert substrate using 0, 25, 50, 100, or 200 milligrams hydroxyapatite (hap) (ca(10)[po(4)](6)[oh](2)) per pot as a p amendment. plant and nodule dry weights and nodule activity increased for both vam and control plants with increasin ...	1982	16662513
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
significance of hydrogen evolution in the carbon and nitrogen economy of nodulated cowpea.	the carbon and nitrogen economies of a single cultivar of cowpea (vigna unguiculata (l.) walp.cv caloona) nodulated with either a high h(2)-evolving strain (176a27) or a low h(2)-evolving strain (cb756) of rhizobium were compared. the two symbioses did not differ in total dry matter production, seed yield, nitrogen fixed, the spectrum of nitrogenous solutes produced by nodules for export, or the partitioning of net photosynthate within the plant throughout the growth cycle. detailed examination ...	1983	16662769
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
a comparison of the surface polysaccharides from rhizobium leguminosarum 128c53 smrif with the surface polysaccharides from its exo mutant.	the surface polysaccharides of rhizobium leguminosarum 128c53 sm(r)rif(r) (parent) and its exo(-1) mutant were isolated and characterized. the parent carries out normal symbiosis with its host, pea, while the exo(-1) mutant does not nodulate the pea. the following observations were made. (a) the parent produces lipopolysaccharide (lps), typical acidic extracellular polysaccharide (eps), and three additional polysaccharides, ps1, ps2, and ps3. the ps1 and ps2 fractions are likely to be the capsul ...	1983	16662808
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
effect of the host legume on acetylene reduction and hydrogen evolution by rhizobium nitrogenase.	the relative efficiency (re) of n(2) fixation (re = 1 - [h(2) evolved in air]/[acetylene reduced]) was investigated in a rhizobium strain lacking uptake hydrogenase activity (hup(-)). variation in re of such strains presumably reflects changes in the electron allocation coefficient of nitrogenase. by artificially extending the normal dark period of 24-day-old pisum sativum l. cv ;alaska' inoculated with the hup(-)r. leguminosarum strain 3740, reproducible changes in re were obtained. the re show ...	1983	16662950
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
effect of rhizobial strain and host plant on nitrogen isotopic fractionation in legumes.	lotus pedunculatus l., medicago sativa l., macroptilium atropurpureum, glycine max, and trifolium repens l. were grown in a n-free medium and inoculated with one of ten rhizobium strains. dry matter, n content, and delta(15)n values were determined for various plant parts.nodules, with the exception of those from lucerne, were enriched in (15)n relative to atmospheric n. considerable variation was found in delta(15)n values of plant herbage (-4.5 to +0.8). the extent of isotopic discrimination w ...	1983	16663110
host plant cultivar effects on hydrogen evolution by rhizobium leguminosarum.	the effect of host plant cultivar on h(2) evolution by root nodules was examined in symbioses between pisum sativum l. and selected strains of rhizobium leguminosarum. hydrogen evolution from root nodules containing rhizobium represents the sum of h(2) produced by the nitrogenase enzyme complex and h(2) oxidized by any uptake hydrogenase present in those bacterial cells. relative efficiency (re) calculated as re = 1 - (h(2) evolved in air/c(2) h(2) reduced) did not vary significantly among ;felt ...	1983	16663112
role of inosine monophosphate oxidoreductase in the formation of ureides in nitrogen-fixing nodules of cowpea (vigna unguiculata l. walp.).	cell-free extracts from nodules of cowpea (vigna unguiculata l. (walp.) cv caloona:rhizobium strain cb756) prepared in the presence of 15% (v/v) glycerol showed high rates (30 to 60 nanomoles nad reduced per minute per gram fresh weight nodule) of inosine monophosphate oxidoreductase (ec 1.2.1.14) activity. the enzyme was labile (half-life of activity less than 3 hours) but could be stabilized for up to 18 hours by inclusion of the substrates nad and inosine monophosphate in the breaking media. ...	1983	16663115
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
phytohormones, rhizobium mutants, and nodulation in legumes : iii. auxin metabolism in effective and ineffective pea root nodules.	high specific activity [(3)h]indole-3-acetic acid (iaa) was applied to the apical bud of intact pea (pisum sativum l. cv greenfeast) plants. radioactivity was detected in all tissues after 24 hours. more radioactivity accumulated in the nodules than in the parent root on a fresh weight basis and more in effective (nitrogen-fixing) nodules than in ineffective nodules (which do not fix nitrogen).for most samples, thin layer chromatography revealed major peaks of radioactivity at the r(f) values of ...	1983	16663219
effect of temperature on nitrogenase functioning in cowpea nodules.	nitrogenase (ec 1.7.99.2) activity of a cowpea (vigna unguiculata (l.) walp cv caloona) symbiosis formed with a rhizobium strain (176a27) lacking uptake hydrogenase and maintained under conditions of a 12-hour day at an air temperature of 30 degrees c (800-1000 microeinsteins per square meter per second) and a 12-hour night at an air temperature of 20 degrees c showed a marked diurnal variation in ratio of nitrogen fixed to hydrogen evolved. as little as 0.3 micromole nitrogen was fixed per micr ...	1983	16663226
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
organization and expression of rhizobium meliloti nitrogen fixation genes.	the boundaries of a nif gene cluster in rhizobium meliloti were determined by tn5 mutagenesis. these genes are clustered within a 14- to 15-kilobase (kb) region that includes the nitrogenase structural genes. sequences within 10 kb on either side of this region are devoid of symbiotically essential gene function. rna blot analysis identified a 5- to 6-kb transcript that corresponds to the nitrogenase structural gene operon. the 5' end of this transcript and its polarity were determined by nuclea ...	1983	16593313
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
hemoglobin in a nonleguminous plant, parasponia: possible genetic origin and function in nitrogen fixation.	a dimeric hemoglobin was purified from nitrogen-fixing root nodules formed by association of rhizobium with a nonleguminous plant, parasponia. the oxygen dissociation rate constant is probably sufficiently high to allow parasponia hemoglobin to function in a fashion similar to that of leghemoglobin, by oxygen buffering and transport during symbiotic nitrogen fixation. the identification of hemoglobin in a nonlegume raises important questions about the evolution of plant hemoglobin genes.	1983	17816020
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
parasitism of rotylenchulus reniformis on soybean root rhizobium nodules in venezuela.		1983	19295793
cloning of the symbiotic region of rhizobium leguminosarum: the nodulation genes are between the nitrogenase genes and a nifa-like gene.	the region of the rhizobium leguminosarum plasmid prl1ji involved in nodulation and nitrogen fixation has been cloned on a series of four overlapping cosmid clones. these clones represent 60 kb of prl1ji dna on which a series of tn5-induced fix and nod alleles have been identified, with the two most distant alleles being separated by 45 kb of dna. the mutant alleles fell into three groups, two clusters of fix alleles separated by one cluster of nod alleles. within one group of fix alleles, dna h ...	1983	16453461
nodule-specific host proteins in effective and ineffective root nodules of pisum sativum.	nodule-specific root proteins - so called nodulins - were identified in root nodules of pea plants by an immunological assay. nodulin patterns were examined at different stages of nodule development. about 30 nodulins were detectable during development. some were preferentially synthesized before nitrogen fixation started, whereas the majority were synthesized concomitantly with leghaemoglobin. some of the nodulins were located within the peribacteroid membrane. ineffective rhizobium strains (a ...	1983	16453462
motility and chemotaxis of rhizobium meliloti in soil.	the spreading of rhizobium meliloti strains in various autoclaved soils was measured by using simple modifications of established techniques. behavioral mutants were used to demonstrate that efficient spreading requires active motility and chemotaxis. the rate of spreading was affected by physical or chemical differences among soils and by changes in water content.	1983	16346435
survival of rhizobium phaseoli in coal-based legume inoculants applied to seeds.	eight coals used as carriers in legume inoculants promoted the survival of rhizobium phaseoli on pinto bean seeds. although peat was more protective, most coal-based inoculants provided >10 viable rhizobia per seed after 4 weeks.	1983	16346218
free-living rhizobium strain able to grow on n(2) as the sole nitrogen source.	a rhizobium strain isolated from stem nodules of the legume sesbania rostrata was shown to grow on atmospheric nitrogen (n(2)) as the sole nitrogen source. non-n(2)-fixing mutants isolated directly on agar plates formed nodules that did not fix n(2) when inoculated into the host plant.	1983	16346220
effect of acidity on the composition of an indigenous soil population of rhizobium trifolii found in nodules of trifolium subterraneum l.	acidity affected which members of an indigenous soil population of rhizobium trifolii nodulated trifolium subterraneum l. cv. mt. barker. in three experiments involving plants grown either in mineral salts agar adjusted to ph 4.8 or 6.8 and inoculated with a soil suspension or grown directly in samples of unamended soil (ph 4.8) or soil amended with caco(3) (ph 6.4), 121 of 151 isolates of r. trifolii were placed into four serogroups. seventy-nine of these isolates were placed into two serogroup ...	1983	16346425
congo red absorption by rhizobium leguminosarum.	congo red absorption is generally considered a contraindication of rhizobium. however, r. leguminosarum takes up the dye on yeast extract-mannitol agar. the uptake of congo red varies among strains of r. leguminosarum, as shown elsewhere with strains of r. trifolii and r. meliloti. congo red absorption does not distinguish rhizobia from other bacteria, but may be useful as a strain marker.	1983	16346177
production of antimicrobial and bacteriocin-like substances by rhizobium trifolii.	rhizobium trifolii strains iari and rel-1 produced substances with broad and narrow activity spectra, respectively. reproducible inhibitory zones of various sizes produced by r. trifolii iari (2 to 14 mm) and r. trifolii rel-1 (2 to 6 mm) were detected, depending upon the indicator organism used. the maximum production of these substances by both strains of r. trifolii was observed on l-arabinose agar. a preliminary characterization of the antimicrobial substance produced by strain iari showed r ...	1983	16346202
population changes and persistence of rhizobium phaseoli in soil and rhizospheres.	the impact of legume cultivation on the establishment and persistence of an inoculant strain of rhizobium phaseoli and its ability to compete with a resident population of r. phaseoli for nodule occupancy was examined utilizing strain-specific fluorescent antibodies. the soil (hubbard loamy sand) was inoculated homogeneously with 5 x 10 cells per g of soil and confined in plastic cylinders kept in field plots. inoculated and uninoculated cylinders were either left fallow or planted to two seeds ...	1983	16346203
identification of rhizobium phaseoli strains that are tolerant or sensitive to soil acidity.	a study was conducted to determine whether the survival of rhizobium phaseoli in acid soils could be predicted on the basis of the tolerance of the organism to acidity in culture. of 16 strains tested, all grew in culture at ph 4.6, but only those that grew at ph 3.8 survived in soils having ph values of 4.1 to 4.6. strains that tolerated the lowest ph values in culture were tolerant of the highest aluminum concentrations. in one acid soil, an acid-tolerant strain was unable to survive in number ...	1983	16346239
hydrogen recycling by rhizobium leguminosarum isolates and growth and nitrogen contents of pea plants (pisum sativum l.).	the ability to recycle h(2) evolved by nitrogenase is thought to be of importance in increasing the efficiency of n(2) fixation and to be a factor in increasing plant yield in symbiotic systems. to determine whether this ability is a significant factor in the rhizobium leguminosarum-pisum sativum l. system, plants were inoculated with r. leguminosarum isolates which differed in their ability to oxidize h(2) and in their relative efficiency of n(2) fixation. these plants were grown at three level ...	1983	16346248
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
competition among rhizobium leguminosarum strains for nodulation of lentils (lens esculenta).	thirty-one cultures of rhizobium leguminosarum were screened for effectiveness (c(2)h(2) reduction) on lentils (lens esculenta). fluorescent antibodies prepared against three of the most effective strains (hawaii 5-0, nitragin 92a3, and nitragin 128a12) exhibited a high degree of strain specificity; the antibodies reacted strongly with their homologous rhizobia in culture and with bacteroids in nodules. they did not cross-react with one another, and only weakly with 5 of the 47 other r. legumino ...	1983	16346257
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
effects of carrier and temperature on survival of rhizobium spp. in legume inocula: development of an improved type of inoculant.	the effects of inoculant carrier, temperature, and storage period on the survival of rhizobium strains were determined by plate count and most-probable-number analyses. preliminary experiments showed that survival of rhizobia was affected by each of these factors and their interactions. results of further studies indicated that six strains of rhizobia survived better at high temperatures when lyophilized and suspended in an oil carrier as compared to finely ground peat. the oil base inocula cont ...	1983	16346313
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
interaction of agromyces ramosus with other bacteria in soil.	agromyces ramosus occurs in very high numbers in most soils and, based on studies of laboratory isolates, does not require host cells for growth. nevertheless, it attacked and destroyed most of the gram-positive and gram-negative bacterial species tested as possible host organisms. a. ramosus also attacked and destroyed saccharomyces cerevisiae. the possibility of attack on fungi was unclear. among the bacteria serving as hosts were the important soil species azotobacter vinelandii, rhizobium le ...	1983	16346402
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
free-living rhizobium strain able to grow on n(2) as the sole nitrogen source.	[this corrects the article on p. 711 in vol. 45.].	1983	16346430
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
the conserved part of the t-region in ti-plasmids expresses four proteins in bacteria.	the t-region of ti-plasmids expresses four proteins (mol. wts. 74,000, 49,000, 28,000 and 27,000) in escherichia coli minicells. promoter activities are determined by sequences within the t-region, and the protein-coding regions map in that part of the t-region which is highly conserved in octopine and nopaline plasmids and which is responsible for shoot and root inhibition when expressed in plant cells. three of the regions expressed in bacteria correlate with three regions which are transcribe ...	1983	11894956
intergeneric transfer and exchange recombination of restriction fragments cloned in pbr322: a novel strategy for the reversed genetics of the ti plasmids of agrobacterium tumefaciens.	transmission of cole1/pmb1-derived plasmids, such as pbr322, from escherichia coli donor strains was shown to be an efficient way to introduce these plasmids into agrobacterium. this was accomplished by using e. coli carrying the helper plasmids pgj28 and r64drd11 which provide the cole1 mob functions and tra functions, respectively. for example, the broad host-range replication plasmid, pgv1150, a co-integrate plasmid between pbr322 and the w-type mini-sa plasmid, pgv1106, was transmitted from ...	1983	11894957
identification of sequences involved in the polyadenylation of higher plant nuclear transcripts using agrobacterium t-dna genes as models.	sequences in the 3'-untranslated region of two different octopine t-dna genes were analyzed with regard to their significance in polyadenylation. poly(a) addition sites were localized precisely by s1 nuclease mapping with t-dna-derived mrnas isolated from tobacco. the gene encoding transcript 7' contains two aataaa hexanucleotides, respectively 119 bp and 170 bp downstream of the taa stop codon. a single poly(a) site was mapped 24-25 bp downstream of the first aataaa. further, we show that a mut ...	1983	11894958
morphology of root nodules and nodule-like structures formed by rhizobium and agrobacterium strains containing a rhizobium meliloti megaplasmid.	we examined expression of the megaplasmid prme41b of rhizobium meliloti in two different rhizobium sp. strains and in agrobacterium tumefaciens. transfer of prme41b into these bacteria was facilitated by insertion of a recombinant plasmid coding for mobilization functions of rp4 into the nif region (kondorosi, a., e. kondorosi, c.e. pankhurst, w. j. broughton, and z. banfalvi, 1982, mol. gen. genet., 188:433-439). in all cases, transconjugants formed nodule-like structures on the roots of medica ...	1983	6885919
detection of antibacterial substances in some plant residues and their effect on certain micro-organisms.	the effect of dry residues from several plants, belonging to different families on certain microorganisms in vitro and in vivo, was studied. dry residues of paprica leaves, tomato tops, egg plant leaves, guava leaves, onion peels, garlic tops, wheat straw, sugar cane leaves, cotton leaves, egyptian clover tops, field bean tops or pea tops were examined for the presence of antibacterial substances, using successive extractions with hexane, ethyl ether, ethanol, and water, respectively, for each p ...	1983	6845904
stereochemistry of an alpha, beta-elimination reaction by d-glucosaminate dehydratase.	the proton nmr analysis of d-glucosaminate dehydratase reaction in d2o revealed the incorporation of a deuterium atom at c-3 carbon of the product, 2-keto-3-deoxy-d-gluconate. based on the chemical shift of c-3 proton of the product and the coupling constant characteristic for the c-3 and c-4 axial-axial coupling in the 2c5 pyranose conformation, the deuterium is in the pro-s position. thus, the dehydration of d-glucosaminate by the enzyme proceeds in a retention mode at c-3 carbon. kinetic para ...	1983	6852253
a new opine derived from nopaline.	nopaline (n-[4-[(aminoiminomethyl)amino-]-1s-carboxybutyl]-2r-aminopentanedioic acid and isonopaline (n-[4-[(aminoiminomethyl)amino-1s-carboxybutyl]- 2s-aminopentanedioic acid) have been synthesized and separated by crystallization. in addition, a derivative of each of these compounds that forms spontaneously from the parent compounds under the usual crystallization conditions was isolated and characterized. the chemical properties, elemental analysis, 1h-nmr spectrum, and electrophoretic behavi ...	1983	6863246
[demonstration of a metabolic property of rhibozium meliloti usable for its classification].	fast-growing rhizobium and agrobacterium strans were studied for their behaviour towards two carbohydrates (glucose and fructose) according to the following criteria: acidification and soluble exopolysaccharide production by resting cells. r. meliloti and agrobacterium spp. showed a similar behaviour: in glucose-containing medium, acidification occurred and few exopolysaccharides were produced, whereas in medium supplemented with fructose, a neutral ph was maintained and large amounts of exopoly ...	1983	6870083
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
symbiotic properties of c4-dicarboxylic acid transport mutants of rhizobium leguminosarum.	the transport of succinate was studied in bacteroids of an effective, streptomycin-resistant strain (gf160) of rhizobium leguminosarum. high levels of succinate transport occurred, and the kinetics, specificity, and sensitivity to metabolic inhibitors were similar to those previously described for free-living cells. the symbiotic properties of two transposon (tn5)-mediated c4-dicarboxylate transport mutants (strains gf31 and gf252) were determined. strain gf31 formed ineffective nodules, and bac ...	1983	6853448
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
genetic analysis of t-dna transcripts in nopaline crown galls.	plant crown gall tumor cells result from the insertion and expression of a defined dna sequence, called t-dna, which is derived from the ti plasmid, harbored by agrobacterium tumefaciens strains. to study the function of the genes of the t-dna of the nopaline ti plasmid, ptic58, a collection of mutants was isolated so that t-dna genes are inactivated either separately or in various combinations. it was found that no single t-dna gene or t-region border is absolutely essential for stable tumor fo ...	1983	6839358
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
[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
polysaccharide production by certain antibiotic resistant mutants of rhizobium sp (cowpea miscellany).		1983	6629842
structure of t-dna in roots transformed by agrobacterium rhizogenes.	dna isolated from hairy roots incited on daucus carota by agrobacterium strains harboring the ri plasmid was probed with ri plasmid fragments to identify plasmid sequences transferred and integrated into the plant genome. one hairy root line was incited by an a. rhizogenes natural isolate strain harboring two large plasmids in addition to the ri plasmid. dna from hairy roots incited by this strain contained a total of five nonidentical copies of t-dna which together comprised a t-dna complement ...	1983	6875427
biosynthesis of amino acids from sucrose and krebs cycle metabolites by rhizobium lupini bacteroids.	the possibility of amino acids biosynthesis from sucrose, metabolites of krebs cycle or glyoxylate and ammonium by intact bacteroids has been studied. the suspension of intact rhizobium lupini bacteroids in phosphate buffer solution ph 7.8 was shown to catalyse the biosynthesis from sucrose and ammonium of some amino acids, such as alanine, aspartic and glutamic acids, glycine and serine. the yield of alanine and aspartic acid was 2.5-3 times higher than that of other amino acids, which were for ...	1983	6855750
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
[comparative evaluation of the use of glucose and fructose by the oxidative pathway in a strain of rhizobium meliloti].	the oxidation rate in resting cells of rhizobium meliloti was investigated with either glucose or fructose as substrate. fructose uptake was found to be complete, whereas glucose uptake did not fully occur, yielding 2-kitogluconic acid in the medium. at the end of fructose oxidation, significant levels of this substrate and its derivatives had accumulated in the bacteria.	1983	6681255
methylammonium uptake by rhizobium sp. strain 32h1.	we present evidence that methylammonium is transported into cowpea rhizobium sp. strain 32h1 cells by a membrane carrier whose natural substrate is ammonium. after growth in low (0.2%) oxygen, which is necessary for nitrogen fixation by these cells, respiring rhizobial cells took up [14c]methylammonium to high intracellular levels. cells grown in atmospheric (21%) oxygen did not take up methylammonium. uptake (transport plus metabolism) was maximal in cells harvested in the early stationary phas ...	1983	6826521
plant tumors.		1983	6842759
purification and electron microscopy of a large plasmid of rhizobium meliloti 41.	a large plasmid dna molecule was purified from rhizobium meliloti 41 by cscl-ethidium bromide density gradient centrifugation. electron microscopic and agarose gel electrophoretic data suggest that addition of alkali effectively removes the chromosomal dna, the plasmid dna can be precipitated from the cleared lysate and no gradient centrifugation is needed for plasmid purification.	1983	6659858
relationship between adenylate cytokinin production and ti plasmid of agrobacterium tumefaciens.	to know whether the tumor-inducing plasmid of agrobacterium tumefaciens carries genetic information of the biosynthesis of cytokinins, the levels of 6-(3-methyl-2-butenyl-amino)purine (ipade) and its 4-hydroxy derivative trans-zeatin (trans-z) and its p-beta-d-ribofuranoside (trans-zr) produced in media by wild-type virulent strain, plasmid-cured avirulent strain and the deletion mutant were compared. the highest levels of ipade and trans-z were found in the culture filtrate of late-log phase gr ...	1983	6664842
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
rhizobium infection and nodulation: a beneficial plant disease?		1983	6357057
a general method for the transfer of cloned genes to plant cells.	this paper describes a method for the transfer to plant cells of any cloned gene, regardless of its termini or internal restriction enzyme cleavage sites. a broad host-range intermediate vector, pgv1117, was constructed containing hindiii-23, a right-end t-region fragment of the nopaline plasmid ptic58. using in vivo protection by ecori methylase and ecori linker ligation, a fragment of rabbit chromosomal dna, carrying the beta-globin gene, was inserted into plasmid pgv1117. following transmissi ...	1983	6628995
identification of a rhizobium trifolii plasmid coding for nitrogen fixation and nodulation genes and its interaction with pjb5ji, a rhizobium leguminosarum plasmid.	rhizobium trifolii t37 contains at least three plasmids with sizes of greater than 250 megadaltons. southern blots of agarose gels of these plasmids probed with rhizobium meliloti nif dna indicated that the smallest plasmid, prtt37a, contains the nif genes. transfer of the rhizobium leguminosarum plasmid pjb5ji, which codes for pea nodulation and the nif genes and is genetically marked with tn5, into r. trifolii t37 generated transconjugants containing a variety of plasmid profiles. the plasmid ...	1983	6630147
compatibility of rhizobium japonicum with commercial pesticides in vitro.		1983	6640140
heat curing of a sym plasmid in a fast-growing rhizobium sp. that is able to nodulate legumes and the nonlegume parasponia sp.	genes involved in nodulation of both legumes and the nonlegume parasponia sp., as well as nitrogenase genes, reside on a large plasmid in a fast-growing rhizobium sp. from lablab purpureus. this plasmid can be cured by incubation at elevated temperatures and can be mobilized by the p1 group plasmid rp1::tn501.	1983	6571729
ultrastructural analysis of ineffective alfalfa nodules formed by nif::tn5 mutants of rhizobium meliloti.	ineffective alfalfa nodules formed by rhizobium meliloti nif::tn5 mutants were examined by light and electron microscopy. r. meliloti nifh::tn5 mutants formed nodules that were similar in structure to wild-type nodules except that nifh- bacteroids accumulated a compact, electron-dense body. in contrast to nodules induced by wild type and nifh mutants, nifdk- r. meliloti mutants induced nodules which contained numerous starch grains and prematurely senescent bacteroids. in addition, meristematic ...	1983	6575011
in vitro expression of nitrogenase activity in parasponia-rhizobium strain anu 289.	rhizobium strain anu 289 derepressed nitrogenase activity under defined in vitro conditions. acetylene reduction was detected both in agar and liquid stationary culture. the strain is capable of nitrogen-fixing nodulation of legumes [such as siratro (macroptilium atropurpureum urb] as well as the non-legumes parasponia andersonii and p. rugosa. nitrogenase activity as high as 40-70 nmol c2h4 per mg protein after 7 days of incubation was detected. strain anu 289 was similar to rhizobium strains 3 ...	1983	6575732
a functional map of the nopaline catabolism genes on the ti plasmid of agrobacterium tumefaciens c58.	the nopaline catabolism (noc) genes are located in a 14.4 kb region on the ptic58 plasmid of a. tumefaciens c58. these genes permit the bacterium to grow on nopaline n2-(1,3-dicarboxylpropyl) arginine, a substrate produced in plant tumors initiated by strain c58. the functions of the noc genes include the use of nopaline and l-ornithine as sole carbon and nitrogen sources. using tn5 insertional mutants, we have identified and mapped the positions of the genes that are responsible for nopaline ca ...	1983	6577260
isolation and characterization of the reca gene of rhizobium meliloti.	interspecific complementation of an escherichia coli reca mutant with plasmids containing a gene bank of rhizobium meliloti dna was used to identify a clone which contains the reca gene of r. meliloti. the r. meliloti reca protein can function in recombination and in response to dna damage when expressed in an e. coli reca host, and hybridization studies have shown that dna sequence homology exists between the reca gene of e. coli and that of r. meliloti. the isolated r. meliloti reca dna was us ...	1983	6305915
genetic aspects of biodegradation by pseudomonads.		1983	6315474
klebsiella pneumoniae nifa product activates the rhizobium meliloti nitrogenase promoter.	bacteria in the genus rhizobium normally fix nitrogen only when they interact with leguminous plants to produce on the roots a highly differentiated structure, the nodule, within which the bacteria differentiate into nitrogen-fixing bacteroids. by contrast, the enteric bacterium klebsiella pneumoniae reduces nitrogen in a free-living state in conditions of low oxygen tension and deficiency of fixed nitrogen. in k. pneumoniae, the overall circuitry by which nitrogen-fixation (nif) genes are regul ...	1983	6338395
structural relationships among rhizobium meliloti symbiotic promoters.	symbiotic nitrogen fixation by rhizobium meliloti requires the developmentally specific expression of certain bacterial genes. one set of these genes encodes the subunits of nitrogenase, the enzyme responsible for the reduction of atmospheric dinitrogen to ammonia, and another set consists of closely linked genes also essential for nitrogen fixation. examination of promoter and probable regulatory regions for these gene sets has revealed extensive dna sequence conservation for more than 160 bp u ...	1983	6317191
[cloning and the expression of the r. meliloti nitrogenase gene (nif d) in e. coli].		1983	6321122
recombination deficient mutants of rhizobium meliloti 41.	two mutants deficient in homologous genetic recombination have been isolated from rhizobium meliloti 41 after tn5 mutagenesis. both mutants are defective in the induction of temperate phage 16-3 by uv-light, mytomycin-c or bleomycin, their uv sensitivity is more pronounced than that of the wild-type strain, and they lack the 'sos activity' responsible for induced mutations.	1983	6314090
the detailed physical map of the temperate phage 16-3 of rhizobium meliloti 41.	restriction cleavage maps for enzymes ecori, bamhi, psti, pvuii, xbai and ecorv of rhizobium meliloti temperate phage 16-3 have been established. together with the earlier maps (hindiii, kpni, hpai, bglii) 98 restriction sites, 'evenly' distributed, have been mapped along the phage genome, including the so far unmarked silent region of the chromosome. all the restriction maps have been fitted to each other by computer optimalization. beyond for conventional techniques a computer program (pmap) f ...	1983	6314093
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
[cloning of the ti-plasmid dna fragments of agrobacterium tumefaciens in escherichia coli and the identification of the site of origin of ti-plasmid replication].		1983	6321123