| the 3' untranslated region of a soybean cytosolic glutamine synthetase (gs1) affects transcript stability and protein accumulation in transgenic alfalfa. | higher plants assimilate nitrogen in the form of ammonia through the concerted activity of glutamine synthetase (gs) and glutamate synthase (gogat). the gs enzyme is either located in the cytoplasm (gs1) or in the chloroplast (gs2). glutamine synthetase 1 is regulated in different plants at the transcriptional level and there are some reports of regulation at the level of protein stability. here we present data that clearly establish that gs1 in plants is also regulated at the level of transcrip ... | 2006 | 16460515 |
| alfalfa mob1-like proteins are involved in cell proliferation and are localized in the cell division plane during cytokinesis. | mps-one-binder (mob) proteins play a crucial role in yeast cytokinesis. after cloning two mob1-like genes, msmob1-a and msmob1-b from alfalfa (medicago sativa l.) we show that, although they are constitutively expressed in roots, stems, leaves, flowers and pods, their transcripts and proteins are mostly produced in actively proliferating tissues. a polyclonal antibody specifically raised against msmob1 proteins was used for immunolocalization studies in synchronized root tip cells. the subcellul ... | 2006 | 16460730 |
| estimation of undegradable intake protein in forages using neutral detergent insoluble nitrogen at a single in situ incubation time point. | two experiments were conducted to evaluate the use of neutral detergent insoluble nitrogen (ndin) at a single in situ incubation time point to estimate the undegradable intake protein (uip) in forages as well as to compare rates of ndin degradation. forage samples in exp. 1 comprised diet samples collected from range and meadow pastures monthly from may through september. in exp. 2, clipped samples of alfalfa, birdsfoot trefoil, kura clover, and smooth bromegrass, and diet samples of the mixed l ... | 2006 | 16478957 |
| ruminal in situ disappearance kinetics of nitrogen and neutral detergent insoluble nitrogen from common crabgrass forages sampled on seven dates in northern arkansas. | southern crabgrass (digitaria ciliaris [retz.] koel.) is often an undesirable species in field and forage crops, but visual observations suggest that livestock prefer it to many other summer forages. the objectives of this study were to assess the nutritive value of crabgrass sampled weekly between july 11 and august 22, 2001 and then to determine ruminal in situ disappearance kinetics of n and neutral detergent insoluble n (ndin) for these forages. a secondary objective was to compare these kin ... | 2006 | 16478959 |
| rhizobial exopolysaccharides: genetic control and symbiotic functions. | specific complex interactions between soil bacteria belonging to rhizobium, sinorhizobium, mesorhizobium, phylorhizobium, bradyrhizobium and azorhizobium commonly known as rhizobia, and their host leguminous plants result in development of root nodules. nodules are new organs that consist mainly of plant cells infected with bacteroids that provide the host plant with fixed nitrogen. proper nodule development requires the synthesis and perception of signal molecules such as lipochitooligosacchari ... | 2006 | 16483356 |
| expression of avian reovirus sigmac protein in transgenic plants. | avian reovirus (arv) structural protein, sigmac encoded by s1 genome segment, is the prime candidate to become a vaccine against arv infection. two plant nuclear expression vectors with expression of sigmac-encoding gene driven by camv 35s promoter and rice actin promoter were constructed, respectively. agrobacterium containing the s1 expression constructs were used to transform alfalfa, and transformants were selected using hygromysin. the integration of s1 transgene in alfalfa chromosome was c ... | 2006 | 16488486 |
| effects of codon modification on human bmp2 gene expression in tobacco plants. | bone morphogenetic protein 2 (bmp2) has great potential in therapeutic applications. we are working on generating transgenic plants as a bioreactor to produce bmp2. we have studied the effects of codon optimization on the expression of human bmp2 (hbmp2) in tobacco plants. three modified hbmp2 genes were transformed into tobacco under the control of either cauliflower mosaic virus 35s (camv35s) promoter or double-camv35s promoter plus alfalfa mosaic virus (amv) enhancer. the fused beta-glucuroni ... | 2006 | 16491379 |
| effects of alfalfa and fructooligosaccharide on molting parameters and bone qualities using dual energy x-ray absorptiometry and conventional bone assays. | the aim of this study was to evaluate effects of alfalfa and fructooligosaccharides (fos) on molting performance and bone parameters compared with the conventional feed withdrawal molting procedure. a total of 36 single comb white leghorn hens (84 wk of age) were used for this experiment. the hens were divided into 6 treatment groups with 6 birds per treatment: pre-trial control (pc), full fed (ff), feed withdrawal (fw), 100% alfalfa (a100), a100 + 0.375% fos (a100l), and a100 + 0.75% fos (a100h ... | 2006 | 16493940 |
| [degradation process and plant diversity of alfalfa grassland in north loess plateau of china]. | vegetation recovery and reconstruction is the key of ecosystem restoration in the north loess plateau. with the liudaogou catchment of shenmu county, shaanxi province as test area, this paper studied the dynamics of the plant diversity of artificial alfalfa (medicago sativa) grassland during its degradation process. the results showed that the degradation process of the grassland could be divided into three stages, i.e., artificial alfalfa grassland stage (1-6 yrs), transitional stage from artif ... | 2005 | 16515180 |
| in vivo anthelmintic activity of dorycnium rectum and grape seed extract against ostertagia (teladorsagia) circumcincta and trichostrongylus colubriformis in sheep. | to assess the in vivo anthelmintic activity of condensed tannins (ct) in the forage species dorycnium rectum and medicago sativa, and in an extract from grape (vitus vinifera) seeds (gse), against two species of parasite, teladorsagia (ostertagia) circumcincta and trichostrongylus colubriformis, at different stages of their life cycle, in sheep that were parasite-naïve or previously exposed to nematodes. | 2006 | 16528390 |
| effects of chronic exposure to soy meal containing diet or soy derived isoflavones supplement on semen production and reproductive system of male rabbits. | soy and derivative diets deliver large doses of isoflavones to human and animals throughout their lifespan, including gestation. epidemiologic and experimental data suggest that the consumption of soybean containing foods may protect against cardiovascular disease and decrease breast, prostate and endometrial cancer risk. based on animal and in vitro studies, however, concerns have been raised that consumption of isoflavones may cause potential adverse effects on the reproductive tract and behav ... | 2007 | 16530993 |
| strategies to obtain stable transgenic plants from non-embryogenic lines: complementation of the nn1 mutation of the nork gene in medicago sativa mn1008. | strategies to introduce genes into non-embryogenic plants for complementation of a mutation are described and tested on tetraploid alfalfa (medicago sativa). genes conditioning embryogenic potential, a mutant phenotype, and a gene to complement the mutation can be combined using several different crossing and selection steps. in the successful strategy used here, the m. sativa genotype mnnc-1008(nn) carrying the recessive non-nodulating mutant allele nn ( 1 ) was crossed with the highly embryoge ... | 2006 | 16534599 |
| early interactions of rhizobium leguminosarum bv. phaseoli and bean roots: specificity in the process of adsorption and its requirement of ca(sup2+) and mg(sup2+) ions. | roots of phaseolus vulgaris l. were incubated with dilute suspensions (1 x 10(sup3) to 3 x 10(sup3) bacteria ml(sup-1)) of an antibiotic-resistant indicator strain of rhizobium leguminosarum bv. phaseoli in mineral medium and washed four times by a standardized procedure prior to quantitation of adsorption (g. caetano-anolles and g. favelukes, appl. environ. microbiol. 52:371-376, 1986). the population of rhizobia remaining adsorbed on roots after washing was homogeneous, as indicated by the fir ... | 1995 | 16535005 |
| attenuation of symbiotic effectiveness by rhizobium meliloti saf22 related to the presence of a cryptic plasmid. | several wild-type strains of rhizobium meliloti isolated from alfalfa nodules exhibited different plasmid profiles, yet did not differ in growth rate in yeast-mannitol medium, utilization of 43 different carbon sources, intrinsic resistance to 14 antibiotics, or detection of 16 enzyme activities. in contrast, three measures of effectiveness in symbiotic nitrogen fixation with alfalfa (shoot length, dry weight, and nitrogen content) indicated that r. meliloti saf22, whose plasmid profile differs ... | 1995 | 16535033 |
| greenhouse and field evaluations of an autoselective system based on an essential thymidylate synthase gene for improved maintenance of plasmid vectors in modified rhizobium meliloti. | the stability of the thy autoselective system, based on an essential thymidylate synthase gene, for enhanced maintenance of plasmid vectors in rhizobium meliloti was evaluated in the greenhouse and with field-grown alfalfa. the thy autoselective system consists of a free-replicating, broad-host-range plasmid vector containing a copy of the thya gene from lactococcus lactis subsp. lactis and a spontaneous mutant of r. meliloti deficient in thymidylate synthase (thy(sup-)). under greenhouse condit ... | 1995 | 16535168 |
| effects of a bacterial hay preservative (pediococcus pentosaceus) on hay under experimental storage conditions. | the abundant growth of molds and thermophilic actinomycetes in stored hay decreases its quality and can be hazardous for the producer who inhales these contaminants when the moldy hay is fed in closed barns. these microbes are responsible for a respiratory disease called farmer's lung. products, including bacterial cultures that can be inoculated in hay, are available to prevent hay deterioration by molds and bacteria. the aim of this study was to verify the effectiveness of pediococcus pentosac ... | 1995 | 16535180 |
| inoculation with sinorhizobium meliloti rmbpc-2 increases alfalfa yield compared with inoculation with a nonengineered wild-type strain. | inoculation of alfalfa seeds with any of three recombinant strains of sinorhizobium meliloti significantly increased overall plant biomass compared with inoculation with the wild-type strains over a 3-year period at three locations. a high proportion of nodules were occupied by the inoculum strains throughout the 3-year period. | 1996 | 16535451 |
| occurrence of flavonoids and nucleosides in agricultural soils. | an ecologically relevant soil extraction procedure separated two types of molecules important for bacteria: flavonoids and small hydrophilic organic compounds. two flavonoids, identified previously as inducers of nodulation genes in rhizobium meliloti, were detected in rhizosphere soil from alfalfa (medicago sativa l.). in addition, biologically significant quantities (micromoles per kilogram) of ribonucleosides and deoxyribonucleosides were found in all soils tested. long-term wheat (triticum a ... | 1997 | 16535739 |
| regulation of the phosphate stress response in rhizobium meliloti by phob. | alkaline phosphatase activity and phosphate transport rates in rhizobium meliloti increased significantly when medium phosphate levels decreased to approximately 10 (mu)m. both responses were abolished in a tn5:: phob mutant, but the mutant could be complemented by a plasmid that contained cloned r. meliloti phob. the phob(sup-) mutant had a normal symbiosis phenotype under growth conditions that supplied either limiting or nonlimiting levels of phosphate to the host plant medicago sativa, sugge ... | 1997 | 16535758 |
| sinorhizobium meliloti blub is necessary for production of 5,6-dimethylbenzimidazole, the lower ligand of b12. | an insight into a previously unknown step in b(12) biosynthesis was unexpectedly obtained through our analysis of a mutant of the symbiotic nitrogen fixing bacterium sinorhizobium meliloti. this mutant was identified based on its unusually bright fluorescence on plates containing the succinoglycan binding dye calcofluor. the mutant contains a tn5 insertion in a gene that has not been characterized previously in s. meliloti. the closest known homolog is the blub gene of rhodobacter capsulatus, wh ... | 2006 | 16537439 |
| strain distribution of alfalfa weevil (coleoptera: curculionidae) in an intergrade zone. | strain distribution for the alfalfa weevil, hypera postica (gyllenhal), was determined for the five major alfalfa-growing regions of new mexico. mitochondrial dna from field-collected weevils at each location was digested and sequenced to differentiate among strains. eastern, egyptian, and western strains were recovered, along with a population not matching any known strain. the majority of sites examined had populations of two strains intermingled within a field. this is the first confirmation ... | 2005 | 16539129 |
| inactivation of escherichia coli o157:h7, salmonella typhimurium dt104, and listeria monocytogenes on inoculated alfalfa seeds with a fatty acid-based sanitizer. | alfalfa seeds were inoculated with a three-strain cocktail of escherichia coli o157:h7, salmonella enterica subsp. enterica serovar typhimurium dt104, or listeria monocytogenes by immersion to contain approximately 6 to 8 log cfu/g and then treated with a fatty acid-based sanitizer containing 250 ppm of peroxyacid, 1,000 ppm of caprylic and capric acids (emery 658), 1,000 ppm of lactic acid, and 500 ppm of glycerol monolaurate at a reference concentration of 1x. inoculated seeds were immersed at ... | 2006 | 16541689 |
| determination of undegradable intake protein digestibility of forages using the mobile nylon bag technique. | two experiments were conducted using 2 ruminally and duodenally fistulated steers to determine the digestibility of undegradable intake protein (uip) of smooth bromegrass (bromis inermis), birdsfoot trefoil (lotus coniculatus l.), and heat-treated alfalfa (medicago sativa) using the mobile nylon bag technique. undegradable intake protein was determined using neutral detergent insoluble cp at a single in situ incubation time point based on 75% of the total mean retention time estimated from ivdmd ... | 2006 | 16543566 |
| grain source and processing in diets containing varying concentrations of wet corn gluten feed for finishing cattle. | two experiments were conducted to evaluate combinations of wet corn gluten feed (wcgf) and barley, as well as the particle size of dry-rolled barley and corn, in finishing steer diets containing wcgf. in exp. 1, 144 crossbred steers (initial bw = 298.9 +/- 1.4 kg) were used to evaluate barley (0.566 kg/l and 23.5% ndf for whole barley) and wcgf combinations in finishing diets containing 0, 17, 35, 52, or 69% wcgf (dm basis), replacing barley and concentrated separator byproduct. a sixth treatmen ... | 2006 | 16543577 |
| activation of an alfalfa cyclin-dependent kinase inhibitor by calmodulin-like domain protein kinase. | kip-related proteins (krps) play a central role in the regulation of the cell cycle and differentiation through modulation of cyclin-dependent kinase (cdk) functions. we have identified a cdk inhibitor gene from medicago truncatula (mt) by a yeast two-hybrid screen. the krpmt gene was expressed in all plant organs and cultured cells, and its transcripts accumulated after abscisic acid and nacl treatment. the krpmt protein exhibits seven conserved sequence domains and a pest motif that is also de ... | 2006 | 16553899 |
| dietary modulation of p-nonylphenol-induced polycystic kidneys in male sprague-dawley rats. | we had previously found that p-nonylphenol (np) at 1000-2000 ppm in a soy- and alfalfa-free diet induced severe polycystic kidney disease (pkd) in both male and female pups exposed from gestation day 7 through postnatal day (pnd) 50 and hypothesized that differences in dietary components contributed to the severity of lesions relative to those reported in other studies using similar doses of np. the present study investigated the dietary modulation of np-induced pkd using the same exposure regim ... | 2006 | 16554316 |
| [symbiosis between the nodule bacterium sinorhizobium meliloti and alfalfa (medicago sativa) under salinization conditions]. | two hundred forty-three isolates of alfalfa nodule bacteria (sinorhizobium meliloti) were obtained from legume nodules and soils sampled in the northern aral region, experiencing secondary salinization. isolates obtained from nodules (n isolates) were significantly more salt-tolerant than those from soils (s isolates) when grown in a liquid medium with 3.5% nacl. it was found that wild species of alfalfa, melilot, and trigonella preferably formed symbioses with salt-tolerant nodule bacteria in b ... | 2006 | 16579450 |
| conservation of nodulation genes between rhizobium meliloti and a slow-growing rhizobium strain that nodulates a nonlegume host. | parasponia, a woody member of the elm family, is the only nonlegume genus whose members are known to form an effective nitrogen-fixing symbiosis with a rhizobium species. the bacterial strain rp501 is a slow-growing strain of rhizobium isolated from parasponia nodules. strain rp501 also nodulates the legumes siratro (macroptilium atropurpureum) and cowpea (vigna unguiculata). using a cosmid clone bank of rp501 dna, we isolated a 13.4-kilobase (kb) ecori fragment that complemented insertion and p ... | 1985 | 16593600 |
| isolation and characterization of nodulation genes from bradyrhizobium sp. (vigna) strain irc 78. | an 11.76-kilobase-pair (kb) segment of dna from bradyrhizobium sp. (vigna) strain irc 78 that hybridizes to nodulation genes of rhizobium meliloti strain 41 was isolated. hybridization of the 11.76-kb dna fragment to dna from other bradyrhizobium species revealed a high degree of sequence conservation in this region. transfer of the 11.76-kb segment to nodulation-defective (nod(-)) mutants of r. meliloti restored their ability to induce nodules on medicago sativa (alfalfa). mutants of strain irc ... | 1985 | 16593624 |
| rhizobium meliloti genes required for nodule development are related to chromosomal virulence genes in agrobacterium tumefaciens. | symbiotically essential genes have been identified in rhizobium meliloti that are structurally and functionally related to chromosomal virulence (chv) genes of agrobacterium tumefaciens. homologous sequences also exist in the genomes of other fast-growing rhizobia including rhizobium trifolii, rhizobium leguminosarum, and rhizobium phaseoli. in agrobacterium, the chva and chvb loci are known to be essential for oncogenic transformation of dicotyledonous plants and for attachment to plant cells [ ... | 1986 | 16593714 |
| expression of the nodulation gene noda in rhizobium meliloti and localization of the gene product in the cytosol. | the noda gene of rhizobium meliloti encodes a 21.8-kda protein, which is conserved in several rhizobium species. we overproduced the noda protein as a fusion product with a portion of the lambda ci repressor in escherichia coli. this fusion protein was purified from inclusion bodies by gel and hydroxyapatite chromatography in the presence of nadodso(4). monospecific polyclonal antibodies against the hybrid protein were used to detect the noda protein in the cytosol of e. coli and r. meliloti by ... | 1986 | 16593791 |
| genes for the catabolism and synthesis of an opine-like compound in rhizobium meliloti are closely linked and on the sym plasmid. | in alfalfa nodules induced by rhizobium meliloti strain l5-30 the compound l-3-o-methyl-scyllo-inosamine (3-o-msi) is synthesized. this compound is also catabolized specifically by this strain. its biological properties are therefore similar to the agrobacterium opines. to answer the question whether opine-like compounds ("rhizopines") play a role in a plant symbiotic interaction, we isolated the genes for the catabolism of 3-o-msi (moc genes) and for the induction of its synthesis in the nodule ... | 1987 | 16593802 |
| induction of bradyrhizobium japonicum common nod genes by isoflavones isolated from glycine max. | the early events in legume nodulation by rhizobium spp. involve a conserved gene cluster known as the common nod region. a broad-host-range plasmid (pea2-21) containing a bradyrhizobium japonicum noddabc-lacz translational fusion was constructed and used to monitor nod gene expression in response to soybean root extract. two inducing compounds were isolated and identified. analysis using ultraviolet absorption spectra, proton nuclear magnetic resonance, and mass spectrometry showed that the two ... | 1987 | 16593884 |
| characterization of a gene from a tomato pathogen determining hypersensitive resistance in non-host species and genetic analysis of this resistance in bean. | xanthomonas campestris pv. vesicatoria is the causal agent of leaf spot disease on pepper and tomato. on non-host plants, such as bean, soybean, cowpea, alfalfa, and cotton, x. campestris pv. vesicatoria is unable to cause disease, inducing instead a hypersensitive resistance response (hr). since avirulence genes from x. campestris pv. vesicatoria specifically induce hr in several pepper cultivars, we investigated whether there were avirulence genes governing induction of resistance in non-host ... | 1988 | 16593982 |
| early nodulin genes are induced in alfalfa root outgrowths elicited by auxin transport inhibitors. | rhizobium nod genes are essential for root hair deformation and cortical cell division, early stages in the development of nitrogen-fixing root nodules. nod(-) mutants are unable to initiate nodules on legume roots. we observed that n-(1-naphthyl)phthalamic acid and 2,3,5-triiodobenzoic acid, compounds known to function as auxin transport inhibitors, induced nodule-like structures on alfalfa roots. the nodule-like structures (pseudonodules) were white, devoid of bacteria, and resembled nodules e ... | 1989 | 16594017 |
| identification of sinorhizobium meliloti early symbiotic genes by use of a positive functional screen. | the soil bacterium sinorhizobium meliloti establishes nitrogen-fixing symbiosis with its leguminous host plant, alfalfa, following a series of continuous signal exchanges. the complexity of the changes of alfalfa root structures during symbiosis and the amount of s. meliloti genes with unknown functions raised the possibility that more s. meliloti genes may be required for early stages of the symbiosis. a positive functional screen of the entire s. meliloti genome for symbiotic genes was carried ... | 2006 | 16597978 |
| characterization of three rop gtpase genes of alfalfa (medicago sativa l.). | three cdna clones coding for medicago sativa rop gtpases have been isolated. the represented genes could be assigned to various linkage groups by genetic mapping. they were expressed in all investigated plant organs, although at different level. relative gene expression patterns in response to sinorhizobium infection of roots as well as during somatic embryogenesis indicated their differential participation in these processes. dna sequences coding for altogether six different medicago sp. rop gt ... | 2006 | 16603258 |
| effect of amount and ruminal degradability of soybean meal protein on performance of lactating dairy cows. | twenty-eight holstein cows (4 with ruminal cannulas) were blocked by days in milk into 7 groups and then randomly assigned to 1 of 7 balanced 4 x 4 latin square diet sequences. the diets contained [dry matter (dm) basis] 20% alfalfa silage, 35% corn silage, and 45% concentrate mainly from high-moisture corn and soybean meal. diets differed in crude protein (cp) content and source of protein supplement: diet a) 15.6% cp, 3.7% solvent-extracted soybean meal (ssbm), 4.5% expeller soybean meal (esbm ... | 2006 | 16606733 |
| modeling small-scale dairy farms in central mexico using multi-criteria programming. | milk supply from mexican dairy farms does not meet demand and small-scale farms can contribute toward closing the gap. two multi-criteria programming techniques, goal programming and compromise programming, were used in a study of small-scale dairy farms in central mexico. to build the goal and compromise programming models, 4 ordinary linear programming models were also developed, which had objective functions to maximize metabolizable energy for milk production, to maximize margin of income ov ... | 2006 | 16606736 |
| effect of dietary crude protein concentration on ruminal nitrogen metabolism in lactating dairy cows. | ten lactating holstein cows fitted with ruminal cannulas that were part of a larger feeding trial were blocked by days in milk into 2 groups and then randomly assigned to 1 of 2 incomplete 5 x 5 latin squares. diets contained [dry matter (dm) basis] 25% alfalfa silage, 25% corn silage, and 50% concentrate. rolled high-moisture shelled corn was replaced with solvent-extracted soybean meal to increase crude protein (cp) from 13.5% to 15.0, 16.5, 17.9, and 19.4% of dm. each of the 4 experimental pe ... | 2006 | 16606740 |
| effect of dietary crude protein concentration on milk production and nitrogen utilization in lactating dairy cows. | forty lactating holstein cows, including 10 with ruminal cannulas, were blocked by days in milk into 8 groups and then randomly assigned to 1 of 8 incomplete 5 x 5 latin squares to assess the effects of 5 levels of dietary crude protein (cp) on milk production and n use. diets contained 25% alfalfa silage, 25% corn silage, and 50% concentrate, on a dry matter (dm) basis. rolled high-moisture shelled corn was replaced with solvent-extracted soybean meal to increase cp from 13.5 to 15.0, 16.5, 17. ... | 2006 | 16606741 |
| sinorhizobium meliloti differentiation during symbiosis with alfalfa: a transcriptomic dissection. | sinorhizobium meliloti is a soil bacterium able to induce the formation of nodules on the root of specific legumes, including alfalfa (medicago sativa). bacteria colonize nodules through infection threads, invade the plant intracellularly, and ultimately differentiate into bacteroids capable of reducing atmospheric nitrogen to ammonia, which is directly assimilated by the plant. as a first step to describe global changes in gene expression of s. meliloti during the symbiotic process, we used who ... | 2006 | 16610739 |
| wet corn gluten feed and alfalfa hay levels in dry-rolled corn finishing diets: effects on finishing performance and feedlot nitrogen mass balance. | one-hundred ninety-two crossbred steers (initial bw = 351 +/- 11 kg) were used to determine the effects of removing alfalfa hay (ah) from dry-rolled corn-based diets containing wet corn gluten feed (wcgf) on animal performance and nutrient (n and om) mass balance in open feedlot pens. steers were stratified by weight and assigned randomly to 24 pens (2 x 3 factorial) and fed for 132 d from june to october 2002. experimental diets contained either 0 or 35% wcgf and 0, 3.75, or 7.5% ah, and were f ... | 2006 | 16612023 |
| ghrelin enhances glucose-induced insulin secretion in scheduled meal-fed sheep. | the purpose of this study was to investigate the effects of physiologic levels of ghrelin on insulin secretion and insulin sensitivity (glucose disposal) in scheduled fed-sheep, using the hyperglycemic clamp and hyperinsulinemic euglycemic clamp respectively. twelve castrated suffolk rams (69.8 +/- 0.6 kg) were conditioned to be fed alfalfa hay cubes (2% of body weight) once a day. three hours after the feeding, synthetic ovine ghrelin was intravenously administered to the animals at a rate of 0 ... | 2006 | 16614382 |
| antimicrobial activity of saponins from medicago sp.: structure-activity relationship. | the antimicrobial activity of saponins from medicago sativa, m. arborea and m. arabica against a selection of medically important yeasts, gram-positive and -negative bacteria was investigated. structure-activity growth inhibitory effects of related prosapogenins and sapogenins are also described. increasing antibiotic activity was observed going from the saponin extracts to the sapogenin samples, suggesting that the sugar moiety is not important for the antimicrobial efficacy. activity was espec ... | 2006 | 16619355 |
| the effect of predators and hymenopterous parasites on population fluctuations of alfalfa aphids. | among alfalfa pests in iran three aphid species, green alfalfa aphid acyrthosiphon pisum harris spotted alfalfa aphid therioaphis trifolii forma maculata buckton and blue alfalfa aphid, acyrthosiphon kondoi shinji are important pests. the green alfalfa aphid can be observed all along the growing season particularly from late may to mid june at karaj climate conditions. during this period, the mean monthly maximum temperature and relative humidity were about 28 degrees c and 60-65% respectively. ... | 2005 | 16628912 |
| inhibition of salmonella enterica by plant-associated pseudomonads in vitro and on sprouting alfalfa seed. | foodborne illness due to the consumption of contaminated raw or lightly cooked sprouts is a continuing food safety concern. in this study, we tested several plant-associated pseudomonads for their ability to inhibit the growth of salmonella enterica both in vitro and in situ. an agar spot bioassay method was used with three different media. only pseudomonas fluorescens 2-79 produced clear zones of inhibition when tested against five serovars of s. enterica, and activity was dependent on media ty ... | 2006 | 16629011 |
| investigations of rhizobium biofilm formation. | the development of nitrogen-fixing nodules of the rhizobium-legume symbiosis, especially the early stages of root hair deformation and curling, infection thread formation, and nodule initiation, has been well studied from a genetic standpoint. in contrast, the factors important for the colonization of surfaces by rhizobia, including roots-an important prerequisite for nodule formation-have not been as thoroughly investigated. we developed conditions for analyzing the ability of two fast-growing ... | 2006 | 16629750 |
| crop protection by seed coating. | providence of sufficient and healthy food for increasing human population clears the importance of notice to increasing crop production in company with environmental loss reduction. growth and yield of every plant with sexual reproduction, depends on germination & emergence of sown seeds. seed is a small alive plant that its biological function is protection and nutrition of embryo. biological, chemical and physiological characteristics of seed, affect on plant performance & its resistance to un ... | 2005 | 16637182 |
| detection of alfalfa mosaic virus (amv) in pea field in iran. | during the spring and summer, in 2003-2004, pea viruses were identified in twenty pea fields of tehran. some leaf samples were collected randomly from pea fields of tehran. samples were tested by double antibody sandwich enzyme linked immunosorbent assay (das-elisa) technique using polyclonal antiserum of alfalfa mosaic virus (amv), as-0001, dsmz, braunschweig, germany). the samples were extracted in 0.1 m phosphate buffer ph 7 to 7.5 and inoculated on chenopodium amaranticolor, chenopodium quin ... | 2005 | 16637206 |
| effects of phytoestrogens on testosterone secretion by leydig cells from biłgoraj ganders (anser anser). | the aim of this study was to examine ganders at different stages of the reproductive season and the effect of: (1) diets with high phytoestrogen content and (2) in vitro phytoestrogen treatment on testosterone secretion by isolated leydig cells. thirty-six male biłgoraj geese were fed control diets with low phytoestrogen content (containing grass meal) and diets with high phytoestrogens (containing alfalfa meal and soy). testes were obtained from both groups of ganders at three different times o ... | 2006 | 16641036 |
| assay of substances stimulatory to legume nodule formation. | two methods were developed for the assay of substances stimulatory to the nodulation of bean (phaseolus vulgaris) roots growing from segments of hypocotyl tissue. coconut water was the chief source of active material, but extracts of cotyledons, hypocotyls and leaves of beans and of horse chestnut fruits were also stimulatory. high concentrations of nitrate improved nodulation both in the presence and absence of coconut water. the ash of coconut water was inactive. whole alfalfa seedlings formed ... | 1967 | 16656537 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |