Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| changes in alfalfa stem conductance induced by corynebacterium insidiosum toxin. | a toxin involved in bacterial wilt of alfalfa (medicago sativa l.) has been isolated from cultures of the pathogen, corynebacterium insidiosum, as well as from diseased plants (s. m. ries and g. a. strobel. 1972. physiological plant pathology 2: 133-142). the influence of this toxin, a glycopeptide with a molecular weight of 5 x 10(6), on the water relations of alfalfa was examined. it was found that very small amounts of the toxin (2 mug) significantly reduced stem conductance through 15-cm lon ... | 1975 | 16659122 |
| comparison of dna polymerase of rhizobium meliloti and alfalfa bacteroids. | dna dependent-dna polymerase activity was established and partially purified from extracts of cultured rhizobium meliloti, f-28, and nodule bacteroids (r. meliloti, f-28) of alfalfa plants (medicago sativa). polymerase activity in the partially purified fractions showed characteristic dependence on mg(2+), dna, and a full complement of deoxyribonucleoside triphosphates. dnase activity, preference of "activated" double strand dna, and inhibition by p-chloromercuribenzoate and mncl(2) were respons ... | 1975 | 16659337 |
| wound-induced accumulation of trypsin inhibitor activities in plant leaves: survey of several plant genera. | proteinase inhibitor-inducing factor (piif)-induced accumulation of trypsin inhibitory activity was assayed in leaves of 23 species of plants representing 10 agriculturally important genera. inhibitory activity was assayed in extracts from attached leaves or from excised leaves supplied through the cut petioles for 30 minutes with extracts containing the wound hormone piif, obtained from either tomato leaves or from the leaves of each plant under study. during subsequent incubation in light for ... | 1977 | 16659868 |
| a possible new nucleoside diphosphatase from the cytosol of soybean and alfalfa nodules. | nucleoside diphosphatase activity has been found in the cytosol of soybean (glycine max) and alfalfa (medicago satavia) nodules. the enzyme differs from other diphosphatases in that it does not exhibit a strong preference for one nucleoside diphosphate over another. very little, if any, diphosphatase activity was detected in root extracts of alfalfa and soybean seedlings. | 1977 | 16659936 |
| oxygen inhibition of photosynthesis: i. temperature dependence and relation to o(2)/co(2) solubility ratio. | the magnitude of the percentage inhibition of photosynthesis by atmospheric levels of o(2) in the c(3) species solanum tuberosum l., medicago sativa l., phaseolus vulgaris l., glycine max l., and triticum aestivum l. increases in a similar manner with an increase in the apparent solubility ratio of o(2)/co(2) in the leaf over a range of solubility ratios from 25 to 45. the solubility ratio is based on calculated levels of o(2) and co(2) in the intercellular spaces of leaves as derived from whole ... | 1977 | 16659981 |
| comparison of chorismate mutase isozyme patterns in selected plants. | a wide variety of plants have been assayed to determine if they contain three isozymes of chorismate mutase (ec 5.4.99.5) as does alfalfa (medicago sativa l.) or two isozymes, as does mung bean (phaseolus aureus). the isozymes were separated by disc electrophoresis. all anthophyta with the exception of some closely related leguminosae contained three isozymes of chorismate mutase. the one coniferophyta (a pine), and pterophyta (a fern) and one microphyllophyta (a selaginella) assayed contained t ... | 1978 | 16660432 |
| dna content of free living rhizobia and bacteroids of various rhizobium-legume associations. | the dna content of bacteroids from 22 different rhizobium-legume associations was compared to that of the corresponding free living rhizobium species using laser flow microfluorometry. in all 18 effective associations, the bacteroids had either similar or higher dna content than the free living rhizobia. bacteroid populations isolated from effective clover (trifolium repens) and alfalfa (medicago sativa) nodules had an average dna content of >1.5-fold higher than free living r. trifolii and r. m ... | 1979 | 16660736 |
| carbon exchange rates of shoots required to utilize available acetylene reduction capacity in soybean and alfalfa root nodules. | the co(2)-exchange rate required to make full use of available n(2)-fixation capacity, measured as acetylene reduction, was determined in soybean and alfalfa. carbohydrates of root systems were depleted during a 40-hour dark treatment; then plants were exposed to a 24-hour light period during which different co(2)-exchange rates were maintained with various co(2) concentrations. in three- and four-week-old soybeans and four-week-old alfalfa plants, acetylene-reduction capacity was used fully wit ... | 1980 | 16661368 |
| effect of ph, mg, co(2) and mercurials on the circular dichroism, thermal stability and light scattering of ribulose 1,5-bisphosphate carboxylases from alfalfa, spinach and tobacco. | circular dichroism, differential scanning calorimetry and light-scattering measurements of ribulose 1,5-bisphosphate carboxylase (e.c. 4.1.1.39) from alfalfa, spinach and tobacco show: a) the conformation and thermal stability of the native carboxylases are sensitive to changes in ph and to activation of the enzyme with mg(2+) and co(2). the helical content, denaturation temperature (t(d)) and specific enthalpy of denaturation (deltaq) decreased with increase in ph. addition of mg(2+) and co(2) ... | 1981 | 16662003 |
| transient susceptibility of root cells in four common legumes to nodulation by rhizobia. | root cells of four common legumes were found to remain susceptible to nodulation by rhizobia for only a short period of time. delayed inoculation experiments conducted with these legume hosts indicated that the initially susceptible region of the root became progressively less susceptible if inoculations were delayed by a few hours. profiles of the frequency of nodule formation relative to marks indicating the regions of root and root hair development at the time of inoculation indicated that no ... | 1981 | 16662065 |
| emission of hydrogen sulfide by leaf tissue in response to l-cysteine. | leaf discs and detached leaves exposed to l-cysteine emitted a volatile sulfur compound which was proven by gas chromatography to be h(2)s. this phenomenon was demonstrated in all nine species tested (cucumis sativus, cucurbita pepo, nicotiana tabacum, coleus blumei, beta vulgaris, phaseolus vulgaris, medicago sativa, hordeum vulgare, and gossypium hirsutum). the emission of volatile sulfur by cucumber leaves occurred in the dark at a similar rate to that in the light. the emission of leaf discs ... | 1982 | 16662510 |
| n abundance of nodules as an indicator of n metabolism in n(2)-fixing plants. | this paper expands upon previous reports of (15)n elevation in nodules (compared to other tissues) of n(2)-fixing plants. n(2)-fixing nodules of glycine max (soybeans), vigna unguiculata (cowpea), phaseolus vulgaris (common bean), phaseolus coccineus (scarlet runner bean), prosopis glandulosa (mesquite), and olneya tesota (desert ironwood) were enriched in (15)n. nodules of vicia faba (fava beans), arachis hypogaea (peanut), trifolium pratense (red clover), pisum sativum (pea), lathyrus sativus ... | 1982 | 16662517 |
| specific determination of alpha-amylase activity in crude plant extracts containing beta-amylase. | the specific measurement of alpha-amylase activity in crude plant extracts is difficult because of the presence of beta-amylases which directly interfere with most assay methods. methods compared in this study include heat treatment at 70 degrees c for 20 min, hgcl(2) treatment, and the use of the alpha-amylase specific substrate starch azure. in comparing alfalfa (medicago sativa l.), soybeans (glycine max [l.] merr.), and malted barley (hordeum vulgare l.), the starch azure assay was the only ... | 1983 | 16662809 |
| 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 |
| tissue cultures derived from ineffective root nodules of alfalfa : callus initiation and enzymic comparisons. | callus tissue cultures were developed from apical meristem regions of tumor-like ineffective root nodules of alfalfa. callus growth was a function of tissue source and hormone composition and concentration. callus derived from ineffective nodules also were shown not to contain rhizobium meliloti.glutamate dehydrogenase, glutamine synthetase, glutamate synthase, glutamate oxaloacetate transaminase and phosphoenolpyruvate carboxylase activities were present in callus cultures and in the respective ... | 1984 | 16663985 |
| nodule-specific polypeptides from effective alfalfa root nodules and from ineffective nodules lacking nitrogenase. | in addition to leghemoglobin, at least nine nodule-specific polypeptides from the alfalfa (medicago sativa l.)-rhizobium meliloti symbiosis were identified by immune assay. some of these polypeptides may be subunits of larger proteins but none appeared to be subunits of the same multimeric protein. all nine of the nodule-specific polypeptides were localized to within the plant cytosol; they were not found in extracts of bacteroids or in the peribacteroid space. at least one of these nodule-speci ... | 1985 | 16664146 |
| transport and partitioning of co(2) fixed by root nodules of ureide and amide producing legumes. | nodulated and denodulated roots of adzuki bean (vigna angularis), soybean (glycine max), and alfalfa (medicago sativa) were exposed to (14)co(2) to investigate the contribution of nodule co(2) fixation to assimilation and transport of fixed nitrogen. the distribution of radioactivity in xylem sap and partitioning of carbon fixed by nodules to the whole plant were measured. radioactivity in the xylem sap of nodulated soybean and adzuki bean was located primarily (70 to 87%) in the acid fraction w ... | 1985 | 16664323 |
| proteinase inhibitor i accumulation in tomato suspension cultures : induction by plant and fungal cell wall fragments and an extracellular polysaccharide secreted into the medium. | suspension-cultured cells of tomato accumulate proteinase inhibitor i as the sucrose is depleted from 1% to less than 0.1% in the culture medium. inhibitor i can be prematurely induced to accumulate in the cells by the addition to the medium of the proteinase inhibitor inducing factor, trigalacturonic acid, ethylene glycol chitin, or chitosan. in cultures grown in 0.6% initial sucrose with no inducers added, a uronic acid-rich extracellular polysaccharide appears in the medium during growth of t ... | 1986 | 16664609 |
| two indirect methods for detecting ureide synthesis by nodulated legumes. | two methods were developed for the detection of altered ureide metabolism in legume nodules. both techniques are based on the positive correlation between the presence of high xanthine dehydrogenase (ec 1.2.1.37) specific activity in nodules and the ability of those nodules to produce the ureides, allantoin and allantoic acid. in the first method, nodulated legumes are treated for 2 weeks with a soil drench of allopurinol. after allopurinol treatment, leaves of n(2)-fed, ureide-producing legumes ... | 1986 | 16664857 |
| sodium stimulation of uptake hydrogenase activity in symbiotic rhizobium. | initial observations showed a 100% increase in h(2)-uptake (hup) activity of rhizobium leguminosarum strain 3855 in pea root nodules (pisum sativum l. cv alaska) on plants growing in a baked clay substrate relative to those growing in vermiculite, and an investigation of nutrient factors responsible for the phenomenon was initiated. significantly greater hup activity was first measured in the clay-grown plants 24 days after germination, and higher activity was maintained relative to the vermicul ... | 1986 | 16665057 |
| some enzymes of hydrogen peroxide metabolism in leaves and root nodules of medicago sativa. | leaves and nodules (bacteroids and cytosol) of alfalfa (medicago sativa l. cv aragon) plants inoculated with rhizobium meliloti strain 102f51 have been analyzed for the presence of the enzymes superoxide dismutase (sod, ec 1.15.1.1), catalase (ec 1.11.1.6), and peroxidase (ec 1.11.1.7). all three fractions investigated (leaves, bacteroids, and nodular cytosol) show cu,zn-sod activity. besides, the bacteroids and cytosol of nodules possess cn(-)-insensitive sod activities. studies of sod inactiva ... | 1986 | 16665158 |
| factors influencing the induction of freezing tolerance by abscisic acid in cell suspension cultures of bromus inermis leyss and medicago sativa l. | a 2-gram fresh weight inoculum of bromegrass (bromus inermis leyss. culture bg970) cell suspension culture treated with 7.5 x 10(-5) molar abscisic acid (aba) for 7 days at 25 degrees c survived slow cooling to -60 degrees c. over 80% of the cells in aba treated cultures survived immersion in liquid n(2) after slow cooling to -40 or -60 degrees c. in contrast, a 6-gram fresh weight inoculum only attained a hardiness level of -28 degrees c after 5 days of aba treatment. ethanol (2 x 10(-2) molar) ... | 1987 | 16665261 |
| alfalfa root nodule carbon dioxide fixation : iii. immunological studies of nodule phosphoenolpyruvate carboxylase. | antiserum was prepared in rabbits against purified alfalfa (medicago sativa l.) nodule phosphoenolpyruvate carboxylase (pepc). immunotitration assays revealed that the antiserum recognized the enzyme from alfalfa nodules, uninoculated alfalfa roots, and from soybean nodules. tandem-crossed immunoelectrophoresis showed that the pepc protein from alfalfa roots and nodules was immunologically indistinguishable. the 101 kilodalton polypeptide subunit of alfalfa nodule pepc was identified on western ... | 1987 | 16665469 |
| flavone limitations to root nodulation and symbiotic nitrogen fixation in alfalfa. | transcription of the nodabc genes in rhizobium meliloti is required for root nodule formation in alfalfa (medicago sativa l.) and occurs when specific compounds, such as the flavone luteolin, are supplied by the host plant. results reported here indicate how luteolin in the root and rhizosphere can affect subsequent n(2) fixation and plant growth. previous experiments with ;hairy peruvian 32' (hp32), an alfalfa population produced from ;hairy peruvian' (hp) by two generations of selection for in ... | 1987 | 16665583 |
| trifolitoxin production and nodulation are necessary for the expression of superior nodulation competitiveness by rhizobium leguminosarum bv. trifolii strain t24 on clover. | rhizobium leguminosarum bv. trifolii t24 is ineffective in symbiotic nitrogen fixation, produces a potent antibiotic (referred to here as trifolitoxin) that is bacteriostatic to certain rhizobium strains, and is very competitive for clover root nodulation (ea schwinghamer, rp belkengren 1968 arch mikrobiol 64: 130-145). the primary objective of this work was to demonstrate the roles of nodulation and trifolitoxin production in the expression of nodulation competitiveness by t24. unlike wildtype ... | 1987 | 16665698 |
| role of motility and chemotaxis in efficiency of nodulation by rhizobium meliloti. | spontaneous mutants of rhizobium meliloti l5-30 defective in motility or chemotaxis were isolated and compared against the parent with respect to symbiotic competence. each of the mutants was able to generate normal nodules on the host plant alfalfa (medicago sativa), but had slightly delayed nodule formation, diminished nodulation in the initially susceptible region of the host root, and relatively low representation in nodules following co-inoculation with equal numbers of the parent. when ino ... | 1988 | 16666059 |
| nodulin gene expression in effective alfalfa nodules and in nodules arrested at three different stages of development. | nodulin gene expression was analyzed in effective and ineffective root nodules of alfalfa (medicago sativa l. cv iroquois) elicited by three different rhizobium meliloti mutants: an exob mutant having defective acidic exopolysaccharide that does not fluoresce on plates containing the fluorescent brightener calcofluor; fix21, a spontaneous mutant that has defective lipopolysaccharide and is calcofluor bright; and a rhizobium mutant resulting from a tn5 insertion in the nifh gene of the nif operon ... | 1988 | 16666302 |
| alfalfa root exudates and compounds which promote or inhibit induction of rhizobium meliloti nodulation genes. | using a plate induction assay, we demonstrate that alfalfa exudes inducer of rhizobium meliloti nodulation genes. the inducer is exuded from the infectible zone of the root, accumulates to at least 1 micromolar, and is not affected by 10 millimolar nitrate. no zones of inhibition are observed. a nodulation minus mutant line of alfalfa, mn-1008, exudes normal levels of inducer. r. meliloti grown in rich medium requires ten-fold higher concentrations of luteolin to achieve half-maximal induction a ... | 1988 | 16666315 |
| host-pathogen interactions : xxxii. a fungal glucan preparation protects nicotianae against infection by viruses. | a glucan preparation obtained from the mycelial walls of the fungus phytophthora megasperma f.sp. glycinea and known as an elicitor of phytoalexins in soybean was shown to be a very efficient inducer of resistance against viruses in tobacco. the glucan preparation protected against mechanically transmitted viral infections on the upper and lower leaf surfaces. whether the glucan preparation was applied by injection, inoculation, or spraying, it protected the plants if applied before, at the same ... | 1989 | 16666737 |
| nodule formation is stimulated by the ethylene inhibitor aminoethoxyvinylglycine. | previous researchers found that formation and function of nitrogen-fixing nodules on legume roots were severely inhibited by addition of exogenous ethylene. nodule formation by rhizobium meliloti on medicago sativa was stimulated twofold when the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (avg) was added with the inoculum. stimulation of nodule formation by avg showed a similar concentration dependence as inhibition of ethylene biosynthesis, suggesting that the primary action of avg ... | 1989 | 16667088 |
| interactions among flavonoid nod gene inducers released from alfalfa seeds and roots. | alfalfa (medicago sativa l.) seeds and roots can create complex rhizosphere effects by releasing flavonoids that induce nodulation (nod) genes in rhizobium meliloti. previous reports identified luteolin and 4,4'-dihydroxy-2'-methoxychalcone as strong inducers that are released from seeds and roots, respectively, and 4',7-dihydroxyflavone and 4',7-dihydroxyflavanone as weaker inducers which are exuded by roots. as a first step toward identifying flavonoid interactions that may occur in the rhizos ... | 1989 | 16667124 |
| a chalcone and two related flavonoids released from alfalfa roots induce nod genes of rhizobium meliloti. | flavonoid signals from alfalfa (medicago sativa l.) induce transcription of nodulation (nod) genes in rhizobium meliloti. previous investigations identified the flavone luteolin as an active inducer in alfalfa seed extracts, but the nature of nod inducers released from roots has not been reported. root exudate from 3-day-old alfalfa seedlings was purified and then assayed for biological activity with a nodabc-lacz fusion in r. meliloti. indentities of major nod inducers were established by spect ... | 1989 | 16667146 |
| chrysoeriol and luteolin released from alfalfa seeds induce nod genes in rhizobium meliloti. | flavonoid signals from alfalfa (medicago sativa l.) seed and root exudates induce transcription of nodulation (nod) genes in rhizobium meliloti. the flavone luteolin previously was isolated from alfalfa seeds by other workers and identified as the first nod gene inducer for r. meliloti. our recent study of ;moapa 69' alfalfa root exudates found no luteolin but did identify three other nod gene inducers: 4,4'-dihydroxy-2'-methoxychalcone, 4',7-dihydroxyflavone, and 4',7-dihydroxyflavanone. the go ... | 1990 | 16667231 |
| identification of the large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase as a substrate for transglutaminase in medicago sativa l. (alfalfa). | extracts prepared from floral meristematic tissue of alfalfa (medicago sativa l.) were investigated for expression of the enzyme transglutaminase in order to identify the major protein substrate for transglutaminase-directed modifications among plant proteins. the large polymorphic subunits of ribulose 1,5-bisphosphate carboxylase/oxygenase in alfalfa, with molecular weights of 52,700 and 57,600, are major substrates for transglutaminase in these extracts. this was established by: (a) covalent c ... | 1990 | 16667270 |
| purification and thermal dependence of glutathione reductase from two forage legume species. | alfalfa (medicago sativa l.) and sainfoin (onobrychis viciifolia scop.) are forage legumes that differ in their responses to high and low temperature stresses. thermal limitations on the function of glutathione reductase (ec 1.6.4.2) could adversely affect the ability of the plant to cope with adverse temperatures. our objectives were to (a) purify glutathione reductase from ;cimarron' alfalfa and ;pi 212241' sainfoin and (b) investigate the intraspecies variation in the thermal dependency of gl ... | 1990 | 16667283 |
| rhizobium meliloti exopolysaccharide mutants elicit feedback regulation of nodule formation in alfalfa. | nodule formation by wild-type rhizobium meliloti is strongly suppressed in younger parts of alfalfa (medicago sativum l.) root systems as a feedback response to development of the first nodules (g caetano-anollés, wd bauer [1988] planta 175: 546-557). mutants of r. meliloti deficient in exopolysaccharide synthesis can induce the formation of organized nodular structures (pseudonodules) on alfalfa roots but are defective in their ability to invade and multiply within host tissues. the formation o ... | 1990 | 16667284 |
| stress responses in alfalfa (medicago sativa l.): i. induction of phenylpropanoid biosynthesis and hydrolytic enzymes in elicitor-treated cell suspension cultures. | alfalfa (medicago sativa l.) cell suspension cultures accumulated high concentrations of the pterocarpan phytoalexin medicarpin, reaching a maximum within 24 hours after exposure to an elicitor preparation from cell walls of the phytopathogenic fungus colletotrichum lindemuthianum. this was preceded by increases in the extractable activities of the isoflavonoid biosynthetic enzymes l-phenylalanine ammonia-lyase, cinnamic acid 4-hydroxylase, 4-coumarate coenzyme a-ligase, chalcone synthase, chalc ... | 1990 | 16667295 |
| stress responses in alfalfa (medicago sativa l.): ii. purification, characterization, and induction of phenylalanine ammonia-lyase isoforms from elicitor-treated cell suspension cultures. | l-phenylalanine ammonia-lyase has been purified from elicitor-treated alfalfa (medicago sativa l.) cell suspension cultures using two protocols based on different sequences of chromatofocusing and hydrophobic interaction chromatography. three distinct forms of the intact enzyme were separated on the basis of affinity for octyl-sepharose, with isoelectric points in the range ph 5.1 to 5.4. the native enzyme was a tetramer of m(r) 311,000; the intact subunit m(r) was about 79,000, although polypep ... | 1990 | 16667296 |
| metabolism of tryptophan and tryptophan analogs by rhizobium meliloti. | the alfalfa symbiont rhizobium meliloti rm1021 produces indole-3-acetic acid in a regulated manner when supplied with exogenous tryptophan. mutants with altered response to tryptophan analogs still produce indole-3-acetic acid, but are fix(-) because bacteria do not fully differentiate into the nitrogen-fixing bacteriod form. these mutations are in apparently essential genes tightly linked to a dominant streptomycin resistance locus. | 1990 | 16667364 |
| concurrent synthesis and release of nod-gene-inducing flavonoids from alfalfa roots. | flavonoid signals from alfalfa (medicago sativa l.) induce transcription of nodulation (nod) genes in rhizobium meliloti. alfalfa roots release three major nod-gene inducers: 4',7-dihydroxyflavanone, 4',7-dihydroxyflavone, and 4,4'-dihydroxy-2'-methoxychalcone. the objective of the present study was to define temporal relationships between synthesis and exudation for those flavonoids. requirements for concurrent flavonoid biosynthesis were assessed by treating roots of intact alfalfa seedlings w ... | 1990 | 16667655 |
| stress responses in alfalfa (medicago sativa l.) : v. constitutive and elicitor-induced accumulation of isoflavonoid conjugates in cell suspension cultures. | the isoflavonoid conjugates medicarpin-3-o-glucoside-6''-o-malonate (mgm), afrormosin-7-o-glucoside (ag), and afrormosin-7-o-glucoside-6''-o-malonate (agm) were isolated and characterized from cell suspension cultures of alfalfa (medicago sativa l.), where they were the major constitutive secondary metabolites. they were also found in alfalfa roots but not in other parts of the plant. the phytoalexin medicarpin accumulated rapidly in suspension cultured cells treated with elicitor from colletotr ... | 1990 | 16667691 |
| aspartate aminotransferase in alfalfa root nodules : iii. genotypic and tissue expression of aspartate aminotransferase in alfalfa and other species. | aspartate aminotransferase (aat) plays an important role in nitrogen metabolism in all plants and is particularly important in the assimilation of fixed n derived from the legume-rhizoblum symbiosis. two isozymes of aat (aat-1 and aat-2) occur in alfalfa (medicago sativa l.). antibodies against alfalfa nodule aat-2 do not recognize aat-1, and these antibodies were used to study aat-2 expression in different tissues and genotypes of alfalfa and also in other legume and nonlegume species. rocket i ... | 1990 | 16667896 |
| stress responses in alfalfa (medicago sativa l.): vi. differential responsiveness of chalcone synthase induction to fungal elicitor or glutathione in electroporated protoplasts. | protoplasts derived from cell suspensions of alfalfa (medicago sativa l.) responded to treatment with fungal elicitor (fe) by an increase in endogenous chalcone synthase (chs) activity but were unresponsive to reduced glutathione (gsh). preexposure of protoplasts to polyethylene glycol and electroporation resulted in strong responsiveness to gsh but little change in responsiveness to fe. protoplasts from suspension cultures which had been subcultured more than 12 times lost responsiveness to gsh ... | 1990 | 16667919 |
| alfalfa controls nodulation during the onset of rhizobium-induced cortical cell division. | the formation of first nodules inhibits subsequent nodulation in younger regions of alfalfa (medicago sativa l.) roots by a feedback regulatory mechanism that controls nodule number systemically (g caetano-anollés, wd bauer [1988] planta 175: 546-557). following inoculation with wild-type rhizobium meliloti, almost all infections associated with cortical cell division developed into mature nodules. while the distribution of rhizobium- induced cell divisions closely paralleled the distribution of ... | 1991 | 16667992 |
| flavonoids released naturally from alfalfa seeds enhance growth rate of rhizobium meliloti. | alfalfa (medicago sativa l.) releases different flavonoids from seeds and roots. imbibing seeds discharge 3',4',5,7-substituted flavonoids; roots exude 5-deoxy molecules. many, but not all, of these flavonoids induce nodulation (nod) genes in rhizobium meliloti. the dominant flavonoid released from alfalfa seeds is identified here as quercetin-3-o-galactoside, a molecule that does not induce nod genes. low concentrations (1-10 micromolar) of this compound, as well as luteolin-7-o-glucoside, anot ... | 1991 | 16668056 |
| release and modification of nod-gene-inducing flavonoids from alfalfa seeds. | traces of luteolin, an important rhizobial nod gene inducer in rhizobium meliloti, are released by alfalfa (medicago sativa l.) seeds, but most luteolin in the seed exudate is conjugated as luteolin-7-o-glucoside (l7g). processes affecting the production of luteolin from l7g in seed exudate are poorly understood. results from this study establish that (a) seed coats are the primary source of flavonoids, including l7g, in seed exudate; (b) these flavonoids exist in seeds before imbibition; and (c ... | 1991 | 16668057 |
| stress responses in alfalfa (medicago sativa l.): x. molecular cloning and expression of s-adenosyl-l-methionine:caffeic acid 3-o-methyltransferase, a key enzyme of lignin biosynthesis. | s-adenosyl-l-methionine:caffeic acid 3-o-methyltransferase (comt, ec 2.1.1.6) catalyzes the conversion of caffeic acid to ferulic acid, a key step in the biosynthesis of lignin monomers. we have isolated a functionally active cdna clone (pcomt1) encoding alfalfa (medicago sativa l.) comt by immunoscreening a lambdazapii cdna expression library with anti-(aspen comt) antibodies. the derived amino acid sequence of pcomt1 is 86% identical to that of comt from aspen. southern blot analysis indicates ... | 1991 | 16668418 |
| nodules initiated by rhizobium meliloti exopolysaccharide mutants lack a discrete, persistent nodule meristem. | infection of alfalfa with rhizobium meliloti exo mutants deficient in exopolysaccharide results in abnormal root nodules that are devoid of bacteria and fail to fix nitrogen. here we report further characterization of these abnormal nodules. tightly curled root hairs or shepherd's crooks were found after inoculation with rm 1021-derived exo mutants, but curling was delayed compared with wild-type rm 1021. infection threads were initiated in curled root hairs by mutants as well as by wild-type r. ... | 1992 | 16668605 |
| growth and movement of spot inoculated rhizobium meliloti on the root surface of alfalfa. | inoculum droplets of approximately 10 nanoliter volume and containing about 10 rhizobium meliloti cells were placed onto the root surface of alfalfa seedlings in plastic growth pouches at either the root tip, the position of the smallest emergent root hairs, or at a site midway between these points. the droplets were initially confined to an area of about 0.2 square millimeter at the point of application. by 48 and 96 hours after inoculation, the inoculum bacteria and their progeny were distribu ... | 1992 | 16668744 |
| aspartate aminotransferase in effective and ineffective alfalfa nodules : cloning of a cdna and determination of enzyme activity, protein, and mrna levels. | aspartate aminotransferase (aat) is a key plant enzyme affecting nitrogen and carbon metabolism, particularly in legume root nodules and leaves of c(4) species. to ascertain the molecular genetic characteristics and biochemical regulation of aat, we have isolated a cdna encoding the nodule-enhanced aat (aat-2) of alfalfa (medicago sativa l.) by screening a root nodule cdna expression library with antibodies. complementation of an escherichia coli aat mutant with the alfalfa nodule aat-2 cdna ver ... | 1992 | 16668758 |
| regulation of expression of proteinase inhibitor genes by methyl jasmonate and jasmonic acid. | gel electrophoretic analysis of the proteinase inhibitor proteins induced in tomato leaves by airborne methyl jasmonate (ee farmer, ca ryan [1990] proc natl acad sci usa 87: 7713-7716) revealed the new appearance of inhibitors i and ii and two other, higher molecular mass proteins (63.5 and 87 kilodaltons). northern analysis of methyl jasmonate-induced inhibitors i and ii mrnas in tomato (lycopersicon esculentum) leaves, and of alfalfa trypsin inhibitor (a bowman-birk family inhibitor) mrna in a ... | 1992 | 16668777 |
| induction of somatic embryogenesis using side chain and ring modified forms of phenoxy acid growth regulators. | the induction of somatic embryo development in cell cultures of alfalfa (medicago sativa), celery (apium graveolens), and lettuce (lactuca sativa) was compared for 2,4-dichlorophenoxy-acetic acid (2,4-d) and various phenoxy acid growth regulators. tests using a series of straight chain extensions to the phenoxy acid side chain indicate that phenoxybutanoic acid is active, whereas the phenoxypropanoic and phenoxypentanoic analogs are inactive for the induction of alfalfa embryogenesis. side branc ... | 1992 | 16668836 |
| trigonelline and stachydrine released from alfalfa seeds activate nodd2 protein in rhizobium meliloti. | spectroscopic data (nuclear magnetic resonance, mass spectrometry, ultraviolet-visible) in this study identify trigonelline and stachydrine as major components of alfalfa (medicago sativa l.) seed rinse. moreover, biological assays show that these natural products induce nodulation (nod) gene transcription in rhizobium meliloti by activating the regulatory protein nodd2, but not the homologous nodd1 protein. these findings contrast with the fact that the only previously identified nodd2 activato ... | 1992 | 16669069 |
| rhizosphere selection of highly motile phenotypic variants of pseudomonas fluorescens with enhanced competitive colonization ability. | phenotypic variants of pseudomonas fluorescens f113 showing a translucent and diffuse colony morphology show enhanced colonization of the alfalfa rhizosphere. we have previously shown that in the biocontrol agent p. fluorescens f113, phenotypic variation is mediated by the activity of two site-specific recombinases, sss and xerd. by overexpressing the genes encoding either of the recombinases, we have now generated a large number of variants (mutants) after selection either by prolonged laborato ... | 2006 | 16672487 |
| a method for estimating the relative degree of saponification of xanthophyll sources and feedstuffs. | saponification of xanthophyll esters in various feed sources has been shown to improve pigmentation efficiency in broiler skin and egg yolks. three trials were conducted to evaluate a rapid liquid chromatography procedure for estimating the relative degree of xanthophyll saponification using samples of yellow corn, corn gluten meal, alfalfa, and 6 commercially available marigold meal concentrates. in each trial, samples were extracted using a modification of the 1984 association of official anal ... | 2006 | 16673764 |
| evaluation of abundance of aerobic bacteria in the rhizosphere of transgenic and non-transgenic alfalfa lines. | fourteen genetically modified lines of alfalfa (medicago sativa) containing the gene ov from japanese quail, coding for a methionine-rich protein ovalbumin, were evaluated for nodulation ability and concentration of aerobic bacteria in the rhizosphere. the transgenic lines were derived from a highly regenerable genotype rg9/i-14-22, selected from cv. lucia. on selective media, a higher concentration of ammonifying bacteria, bacterial spores, denitrifying and nitrifying bacteria were observed in ... | 2005 | 16681149 |
| influence of plant ontogeny and abiotic factors on resistance of glandular-haired alfalfa to potato leafhopper (hemiptera: cicadellidae). | laboratory experiments were conducted to characterize the trichome-based defense of glandular-haired alfalfa, medicago sativa l., against the potato leafhopper, empoasca fabae (harris). within-plant variability in leafhopper resistance was examined by caging adult leafhoppers to either basal or apical stem internodes of the leafhopper-resistant, glandular-haired m. sativa genotype g98a or the susceptible, nonglandular-haired m. sativa 'ranger'. young, actively secreting glandular trichomes are l ... | 2006 | 16686157 |
| changes in heat production by mature cows after changes in feeding level. | we hypothesized that adaptation of heat production in the realimented cow would occur over an extended period, and the length of time would be influenced by the level of feed. our objectives were to quantify the changes in heat production of cows after feed restriction and to quantify the effect of level of realimentation on the dynamics of heat production in lightweight cows. forty 4-yr-old nonpregnant, nonlacting cows (4-breed composite: 1/4 hereford, 1/4 angus, 1/4 red poll, and 1/4 pinzgauer ... | 2006 | 16699100 |
| effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings. | to assess the effects of flax addition and flax processing on feedlot performance and carcass characteristics, 128 yearling beef heifers (360 +/- 14 kg of initial bw) were blocked by weight and assigned randomly to feedlot diets that included no flax (control), whole flax (whl), rolled flax (rld; 1,300 microm), or ground flax (grd; 700 microm). heifers were fed a growth diet (31% corn, 30% corn silage, 18% barley malt pellets, 14% alfalfa, 4% linseed meal, and 3% supplement; dm basis) for 56 d, ... | 2006 | 16699112 |
| effects of nitro compounds and feedstuffs on in vitro methane production in chicken cecal contents and rumen fluid. | short-chain volatile fatty acids (vfa) and methane are the products from a wide variety of microorganisms living in the gastrointestinal tract. the objective of this study was to examine effects of feedstuff and select nitro compounds on vfa and methane production during in vitro incubation of laying hen cecal contents and rumen fluid from cattle and sheep. in the first experiment, one of the three nitro compound was added to incubations containing cecal contents from laying hens supplemented wi ... | 2006 | 16701620 |
| intake and performance of lactating cows grazing diverse forage mixtures. | twenty multiparous holstein cows in midlactation grazed pastures of 4 forage mixtures in a 12-wk study repeated during 2 grazing seasons to determine if forage mixture complexity affected intake and productivity of lactating dairy cows. the forage mixtures were 1) orchardgrass plus white clover [2 species (sp)]; 2) orchardgrass, white clover, and chicory (3sp); 3) orchardgrass, tall fescue, perennial ryegrass, red clover, birdsfoot trefoil, and chicory (6sp); and 4) 6sp mixture plus white clover ... | 2006 | 16702282 |
| lethal risk to birds from insecticide use in the united states--a spatial and temporal analysis. | we used pesticide use data and previously published models to estimate the lethal risk to birds from insecticides used in u.s. agriculture. data from the u.s. department of agriculture's national agricultural statistical service (nass, washington, d.c.) were used to assess how the lethal risk to birds has changed over the period 1991 to 2003 and to compare risk among crop types according to the most recently available surveys. because the nass data coverage is incomplete, both with respect to cr ... | 2006 | 16704051 |
| effects of nutritional environment and ram effect on breeding season in range sheep. | effects of season, nutritional environment, and presence of rams on incidence and rate of ovulation in fine-wool sheep in southern new mexico were investigated over 14 months (february 1983-march 1984). number of corpora lutea (cl) were observed each month by laparoscopy in random samples from six ewes in each subgroup. seasonality of ovulation in fine-wool sheep managed on range was much more marked than in animals managed on alfalfa hay in drylot. incidence of ovulation approached zero in rang ... | 1986 | 16726123 |
| epidemiological study on factors influencing fertility indices in israeli dairy herds. | the objective of this study was to determine feeding factors connected with differences in the fertility of israeli kibbutz dairy herds. in an epidemiological case-control survey, data from 30, low-fertility kibbutz dairy herds having a mean overall conception rate of 35% in multiparous cows were compared with the data from 30, high-fertility kibbutz dairy herds having a mean overall conception rate of 48% in multiparous cows. nutritional factors accounted for 67% of the differences between low- ... | 1992 | 16727142 |
| effect of low and high-saponin lines of alfalfa on pea aphid. | pea aphid fed on a high-saponin line of alfalfa showed reduction of reproduction and survival, and disturbance in development of its population. this line negatively influenced aphid probing behaviour, particularly prolonging the non-probing period and probing of the peripheral tissues (epidermis and mesophyll) and shortening the period of phloem sap ingestion. the high-saponin line of alfalfa differed from the low-saponin one by the presence of zanhic acid tridesmoside and a higher level of 3-g ... | 2006 | 16740274 |
| cbra is a stationary-phase regulator of cell surface physiology and legume symbiosis in sinorhizobium meliloti. | sinorhizobium meliloti produces an exopolysaccharide called succinoglycan that plays a critical role in promoting symbiosis with its host legume, alfalfa (medicago sativa). we performed a transposon mutagenesis and screened for mutants with altered succinoglycan production and a defect in symbiosis. in this way, we identified a putative two-component histidine kinase associated with a pas sensory domain, now designated cbra (calcofluor-bright regulator a). the cbra::tn5 mutation causes overprodu ... | 2006 | 16740957 |
| postprandial changes in plasma concentrations of growth hormone and ghrelin around weaning in the goat. | we measured and compared plasma levels of gh and ghrelin in response to feeding in 4-week-old (milk replacer-fed) and 13-week-old (alfalfa hay cube-fed) goats, in order to elucidate whether or not the postprandial regulation of these hormone levels changes around weaning. furthermore, we examined the effects of suckling from the dam or intravenous glucose administration on both hormone and insulin levels in kids. in 4-week-old goats, feeding of a milk replacer diet significantly increased plasma ... | 2006 | 16750532 |
| [modeling of lactic acid fermentation of leguminous plant juices]. | lactic acid fermentation of leguminous plant juices was modeled to provide a comparative efficiency assessment of the previously selected strains of lactic acid bacteria as potential components of starter cultures. juices of the legumes fodder galega, red clover, and alfalfa were subjected to lactic acid fermentation in 27 variants of experiment. local strains (lactobacillus sp. rs 2, lactobacillus sp. rs 3, and lactobacillus sp. rs 4) and the collection strain lactobacillus plantarum bs 933 app ... | 2006 | 16761580 |
| resource availability and quality influence patterns of diet mixing by sheep. | in grazing systems, forage availability is a function of herbivore density, which can influence an animal's ability to be selective. in turn, the influence of food availability on selectivity has the potential to influence plant biodiversity. we hypothesized that the ability of herbivores to mix toxin-containing foods in their diets is a function of the availability of nontoxic foods and the nutritional characteristics of the toxin-containing foods. we evaluated this hypothesis in two trials sim ... | 2006 | 16770717 |
| effect of scraping frequency in a freestall barn on volatile nitrogen loss from dairy manure. | the objective of this investigation was to evaluate the effect of scraping frequency (2x vs. 6x daily) on n volatilization from manure on the floor of a dairy free-stall barn. three trials (crossover design) were conducted in the summers of 2001 and 2002, and in the winter of 2003. nitrogen volatilization was estimated from the change in the n:p ratio in excreta at the time of excretion to the time when manure was scraped from the barn. total n loss was considered a maximum estimate of nh3-n los ... | 2006 | 16772577 |
| effect of selenium supplementation and source on the selenium status of horses. | this study was conducted to determine the effect of se supplementation and source on the se status of horses. eighteen 18-mo-old nonexercised horses were randomly assigned within sex to 1 of 3 treatments: 1) control (ctrl, no supplemental se, 0.15 mg of se/kg of total diet dm); 2) inorganic se (inorg, ctrl + 0.45 mg of se/kg of total diet dm from naseo3); or organic se [org, ctrl + 0.45 mg of se/kg of total diet dm from zinc-l-selenomethionine (availa se, zinpro, corp., eden prairie, mn)]. horse ... | 2006 | 16775058 |
| dissipation of phosalone and diazinon in fresh and dried alfalfa. | the objectives of this study were to determine the persistence of phosalone (s-6-chloro-2,3-dihydro-2-oxobenzoxazol-3-ylmethyl o, o-diethyl phosphorodithioate) and diazinon (o,o-diethyl o-2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate) residues in fresh and baled alfalfa under field conditions. plots of alfalfa were sprayed with each insecticide. fresh alfalfa was sampled up to 20 days after treatment, and dried alfalfa was sampled up to 25 weeks after baling. samples were analyzed for resi ... | 2006 | 16785169 |
| circulating fluidized bed combustion product addition to acid soil: alfalfa (medicago sativa l.) composition and environmental quality. | to reduce s emissions, petroleum coke with a high concentration of s was combusted with limestone in a circulating fluidized bed (cfb) boiler. the combustion process creates a bed product that has potential for agricultural uses. this cfb product is often alkaline and enriched in s and other essential plant nutrients, but also contains high concentrations of ni and v. agricultural land application of cfb product is encouraged, but little information is available related to plant responses and en ... | 2006 | 16787025 |
| fixj: a major regulator of the oxygen limitation response and late symbiotic functions of sinorhizobium meliloti. | sinorhizobium meliloti exists either in a free-living state in the soil or in symbiosis within legume nodules, where the bacteria differentiate into nitrogen-fixing bacteroids. expression of genes involved in nitrogen fixation and associated respiration is governed by two intermediate regulators, nifa and fixk, respectively, which are controlled by a two-component regulatory system fixlj in response to low-oxygen conditions. in order to identify the fixlj regulon, gene expression profiles were d ... | 2006 | 16788198 |
| genetic analysis of a baculovirus, autographa californica nuclear polyhedrosis virus i. isolation of temperature-sensitive mutants and assortment into complementation groups. | temperature-sensitive (ts) mutants were isolated from the baculovirus autographa californica (alfalfa looper) mnpv, grown in spodoptera frugiperda (fall armyworm) cells in the presence of n-methyl-n'-nitro-n-nitrosoguanidine. of 567 plaque isolates screened, 27 were temperature sensitive (ts), representing a mutation frequency of 4.8%. ten ts mutants were studied in detail: six failed to yield nonoccluded virus at 33 degrees c (nov mutants), whereas the other four produced nonoccluded virus but ... | 1979 | 16789180 |
| orientation of the genome of autographa californica nuclear polyhedrosis virus: a proposal. | the nuclear polyhedrosis virus of the alfalfa looper autographa californica contains a double-stranded, circular dna genome. fourteen scientists agreed to accept an orientation of this circular genome with respect to a physical map of the restriction endonuclease cleavage sites. | 1982 | 16789218 |
| vsp accumulation and cold-inducible gene expression during autumn hardening and overwintering of alfalfa. | this study describes the time-course of the accumulation of total soluble proteins (tsps) and vegetative storage proteins (vsps) and of the transcripts of cold-inducible (ci) and vsp-encoding genes in taproots of two alfalfa cultivars (ac caribou and europe) during their acclimation to natural autumn hardening and overwintering conditions in eastern canada. the impact of a defoliation in september on these winter hardening-related changes was also assessed. both concentrations and pools of vsps ... | 2006 | 16798845 |
| effects of three-dimensional and color patterns on nest location and progeny mortality in alfalfa leafcutting bee (hymenoptera: megachilidae). | abstract in alfalfa, medicago sativa l., seed production where high bee densities are released, alfalfa leafcutting bee, megachile rotundata (f.) (hymenoptera: megachilidae), females may enter several nesting holes before locating their nests. such levels of "wrong hole" visits lead to an increase in the time spent by females locating their own nests, thereby decreasing alfalfa pollination efficiency and possibly healthy brood production. the objectives of this study were to determine the effect ... | 2006 | 16813291 |
| expression of active hbmp2 in transgenic tobacco plants. | bone morphogenetic protein 2 (bmp2) is important for bone tissue repair. the goal of this research is to construct a high level human bmp2 (hbmp2) expression system using transgenic tobacco plants as a bioreactor. cauliflower mosaic virus (camv) 35s promoter, alfalfa mosaic virus (amv) enhancer, tobacco mosaic virus (tmv) enhancer, matrix attachment regions (mars) sequence, and "kozak" sequence were used to construct recombinant expression vectors and the high-expression vectors were screened ou ... | 2006 | 16819603 |
| diversity of a stable enrichment culture which is useful for silage inoculant and its succession in alfalfa silage. | alfalfa is a kind of forage that is difficult to ensile for good quality. therefore, inoculants are always used to enhance the preservation of alfalfa silage. through continuous restricted subcultivation, a lactic acid bacteria community (al2) was selected from well-fermented alfalfa silage, which sharply decreased the ph level and produced a large amount of lactic acid. the adding of al2 to alfalfa at ensiling resulted in a more rapid drop in ph and higher levels of lactic acid, and it also red ... | 2006 | 16819954 |
| role of rainfall intensity and hydrology in nutrient transport via surface runoff. | loss of soil nutrients in runoff accelerates eutrophication of surface waters. this study evaluated p and n in surface runoff in relation to rainfall intensity and hydrology for two soils along a single hillslope. experiments were initiated on 1- by 2-m plots at foot-slope (6%) and mid-slope (30%) positions within an alfalfa (medicago sativa l.)-orchardgrass (dactylis glomerata l.) field. rain simulations (2.9 and 7.0 cm h(-1)) were conducted under wet (spring) and dry (late-summer) conditions. ... | 2013 | 16825444 |
| effect of various combinations of alfalfa and standard layer diet on susceptibility of laying hens to salmonella enteritidis during forced molt. | feed deprivation is commonly used by the poultry industry to induce molting and stimulate multiple egg-laying cycles. however, feed deprivation has been observed experimentally to increase susceptibility of poultry to salmonella infections. previous studies indicated that alfalfa was efficacious in reducing salmonella; the present investigation was designed to evaluate the efficacy of combined alfalfa and layer diets on salmonella colonization. leghorn hens over 50 wk of age were divided into 12 ... | 2006 | 16830850 |
| the ntrpr operon of sinorhizobium meliloti is organized and functions as a toxin-antitoxin module. | the chromosomal ntrpr operon of sinorhizobium meliloti encodes a protein pair that forms a toxin-antitoxin (ta) module, the first characterized functional ta system in rhizobiaceae. similarly to other bacterial ta systems, the toxin gene ntrr is preceded by and partially overlaps with the antitoxin gene ntrp. based on protein homologies, the ntrpr operon belongs to the vapbc family of ta systems. the operon is negatively autoregulated by the ntrpntrr complex. promoter binding by ntrp is weak; st ... | 2006 | 16838793 |
| evaluation of dried and wet distillers grains included at two concentrations in the diets of lactating dairy cows. | the purpose of this study was to determine the lactation performance of dairy cows fed dried or wet distillers grains (dg) with solubles (ddgs or wdgs) at 2 dietary concentrations. a trial using 15 cows was designed as a replicated 5 x 5 latin square with periods of 4 wk each and data collected during wk 3 and 4 of each period. diets, on a dry matter basis, were: control, 10% ddgs, 20% ddgs, 10% wdgs, and 20% wdgs. all diets contained 25% corn silage, 25% alfalfa hay, and 50% of the respective c ... | 2006 | 16840630 |
| effects of concentrated separator by-product (desugared molasses) on intake, site of digestion, microbial efficiency, and nitrogen balance in ruminants fed forage-based diets. | in exp. 1, 4 ruminally and duodenally cannulated beef steers (444.0 +/- 9.8 kg) were used in a 4 x 4 latin square with a 2 x 2 factorial treatment arrangement to evaluate the effects of forage type (alfalfa or corn stover) and concentrated separator byproduct (csb) supplementation (0 or 10% of dietary dm) on intake, site of digestion, and microbial efficiency. in exp. 2, 5 wethers (44 +/- 1.5 kg) were used in a 5 x 5 latin square to evaluate the effects of csb on intake, digestion, and n balance ... | 2006 | 16864885 |
| inactivation of escherichia coli 0157:h7 and salmonella on mung beans, alfalfa, and other seed types destined for sprout production by using an oxychloro-based sanitizer. | the efficacy of a stabilized oxychloro-based food grade sanitizer to decontaminate seeds destined for sprout production has been evaluated. by using mung bean seeds as a model system, it was demonstrated that the sanitizer could be used to inactivate a five-strain cocktail of escherichia coli o157:h7 or salmonella introduced onto beans at 10(3) to 10(4) cfu/g. salmonella was more tolerant to stabilized oxychloro than was e. coli o157:h7, with sanitizer levels of >150 and >50 ppm, respectively, b ... | 2006 | 16865888 |
| arabidopsis thaliana is an asymptomatic host of alfalfa mosaic virus. | the susceptibility of arabidopsis thaliana ecotypes to infection by alfalfa mosaic virus (amv) was evaluated. thirty-nine ecotypes supported both local and systemic infection, 26 ecotypes supported only local infection, and three ecotypes could not be infected. no obvious symptoms characteristic of virus infection developed on the susceptible ecotypes under standard conditions of culture. parameters of amv infection were characterized in ecotype col-0, which supported systemic infection and accu ... | 2006 | 16875753 |
| role of non-protein amino acid l-canavanine in autoimmunity. | association of sle and alfalfa was first reported in a volunteer who developed lupus-like autoimmunity while ingesting alfalfa seed for a hypercholesterolemia study. this was corroborated with studies in monkeys fed with alfalfa sprout that developed sle. re-challenge with l-canavanine relapsed the disease. arginine homologue l-canavanine, present in alfalfa, was suspected as a cause. l-canavanine can be charged by arginyl trna synthetase to replace l-arginine during protein synthesis. aberrant ... | 2006 | 16890899 |
| autofluorescence detection of arbuscular mycorrhizal fungal structures in palm roots: an underestimated experimental method. | the aim of this study was to reassess the use of autofluorescence for evaluating am colonization in mycorrhizal roots in the light of criticisms of this method that affirmed that only metabolically inactive arbuscules autofluoresce. it was also investigated whether other mycorrhizal structures, such as hyphae, vesicles and spores, could be detected by autofluorescence, and whether the autofluorescence pattern of am fungal structures could be exploited methodologically, for example, in the detect ... | 2006 | 16893637 |
| ergosterol treatment leads to the expression of a specific set of defence-related genes in tobacco. | ergosterol is the main sterol of most fungi. production of reactive oxygen species after the treatment of tobacco and tomato cells by nano-molar concentrations of ergosterol was previously observed as well as the activation of some stress activated mitogen-activated protein kinases on alfalfa cells. in this paper, the expression of some defence-related genes after the ergosterol treatment of tobacco nicotiana tabacum plants is reported. the gene expression of pathogenesis related proteins of fam ... | 2006 | 16900324 |
| overexpression of bets, a sinorhizobium meliloti high-affinity betaine transporter, in bacteroids from medicago sativa nodules sustains nitrogen fixation during early salt stress adaptation. | sinorhizobium meliloti possesses several betaine transporters to cope with salt stress, and bets represents a crucial high-affinity glycine and proline betaine uptake system involved in the rapid acquisition of betaines by cells subjected to osmotic upshock. using a transcriptional lacz (beta-galactosidase) fusion, we showed that bets is expressed during the establishment of the symbiosis and in mature nitrogen-fixing nodules. however, neither nod nor fix phenotypes were impaired in a bets mutan ... | 2006 | 16903355 |
| isolation of a novel nodulin: a molecular marker of osmotic stress in glycine max/bradyrhizobium japonicum nodule. | symbiotic n(2) fixation of legume crops is highly sensitive to drought, which results in a dramatic drop of n accumulation and yield. the symbiosis between soybean (glycine max) and bradyrhizobium japonicum, because of its extreme sensitivity to drought, was chosen as a model to analyse the response to drought stress at a molecular level. the mrna differential display technique was performed to isolate cdna markers differentially expressed in well-watered [100% of n(2) fixation capacity (nfc)] a ... | 2006 | 16913873 |
| long-term field release of bioluminescent sinorhizobium meliloti strains to assess the influence of a reca mutation on the strains' survival. | a field release experiment was carried out to study the fate of the isogenic, firefly luciferase (luc) gene-tagged sinorhizobium meliloti strains l1 (reca-) and l33 (reca+) in the environment. both strains were released at concentrations of approximately 10(6) cfu g(-1) soil in replicate and randomized field plots, which had been sown with alfalfa (medicago sativa). the survival of both strains during the following 7 years could be subdivided into three phases: a sharp decline for more than two ... | 2006 | 16924432 |
| detection of escherichia coli in packaged alfalfa sprouts with an electronic nose and an artificial neural network. | a rapid method for the detection of escherichia coli (atcc 25922) in packaged alfalfa sprouts was developed. volatile compounds from the headspace of packaged alfalfa sprouts, inoculated with e. coli and incubated at 10 degrees c for 1, 2, and 3 days, were collected and analyzed. uninoculated sprouts were used as control samples. an electronic nose with 12 metal oxide electronic sensors was used to monitor changes in the composition of the gas phase of the package headspace with respect to volat ... | 2006 | 16924908 |
| [a luxr family regulator, expr regulates the expression of motc operon from sinorhizobium meliloti]. | in sinorhizobium meliloti strain rm1021, expr+ mutation results in the overproduction of eps ii, which is required for efficient invasion of root nodules on the host plant alfalfa. when rhizobia were grown in lb/mc medium for 36-hour then placed at room temperature, most of expr+ mutant (rm8530) cells aggregated at the bottom of the tubes, but expr+ sinr double mutant rm11528 and wild type rm1021 did not. the expr+ mutant was also found to swim slower than rm1021 on swarming plates, but the expr ... | 2006 | 16933625 |
| detection and differentiation of xylella fastidiosa strains acquired and retained by glassy-winged sharpshooters (hemiptera: cicadellidae) using a mixture of strain-specific primer sets. | xylella fastidiosa wells is a bacterial pathogen that causes a variety of plant diseases, including pierce's disease (pd) of grapevine, almond leaf scorch, alfalfa dwarf, citrus variegated chlorosis, and oleander leaf scorch (ols). numerous strains of this pathogen have been genetically characterized, and several different strains occur in the united states. the dominant vector in southern california is the glassy-winged sharpshooter, homalodisca coagulata (say) (hemiptera: cicadellidae). the hi ... | 2006 | 16937656 |
| yield and forage quality of glandular-haired alfalfa under alfalfa weevil (coleoptera: curculionidae) and potato leafhopper (hemiptera: cicadellidae) pest pressure in virginia. | cultivars of glandular-haired alfalfa, medicago sativa l., such as '54h69', are currently available and marketed as being resistant to potato leafhopper, empoasca fabae (harris) (hemiptera: cicadellidae). 54h69 and a standard, nonglandular-haired alfalfa 'choice' were evaluated at two locations in virginia over a 3-yr period. dry matter yields and concentrations of crude protein and acid detergent fiber were compared at the first, second, and third harvests. overall, the two cultivars produced s ... | 2006 | 16937677 |
| cloning, expression, and mapping of gdp-d-mannose pyrophosphorylase cdna from tomato (lycopersicon esculentum). | gdp-d-mannose pyrophosphorylase (gmp, ec 2.7.7.22) catalyzes the synthesis of gdp-d-mannose and represents the first committed step in plant ascorbic acid biosynthesis. using potato gmp cdna sequence as a querying probe, 65 highly homologous tomato ests were obtained from dbest of genbank and the putative cdna sequence of tomato gmp was assembled. the full-length gmp cdna of tomato was cloned by race-pcr with primers designed according to the assembled cdna sequence. the full-length cdna sequenc ... | 2006 | 16939010 |
| effect of thyme essential oils (thymus hyemalis and thymus zygis) and monensin on in vitro ruminal degradation and volatile fatty acid production. | the effect of the essential oils of thyme on the in vitro ruminal degradability of a barley seed/alfalfa hay substrate was studied. two essential oils were used, one from thymus hyemalis (th), rich in carvacrol, and the other from thymus zygis (tz), rich in thymol. four experimental treatments of in vitro degradability, using the daisy ii(200/220) incubator, were conducted including a negative control (co), a positive control at 7.5 microg/ml of monensin (mo), and two treatments with essential o ... | 2006 | 16939315 |
| metabolite profiles of nodulated alfalfa plants indicate that distinct stages of nodule organogenesis are accompanied by global physiological adaptations. | an effective symbiosis between sinorhizobium meliloti and its host plant medicago sativa is dependent on a balanced physiological interaction enabling the microsymbiont to fix atmospheric nitrogen. maintenance of the symbiotic interaction is regulated by still poorly understood control mechanisms. a first step toward a better understanding of nodule metabolism was the determination of characteristic metabolites for alfalfa root nodules. furthermore, nodules arrested at different developmental st ... | 2006 | 16941904 |