Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| apparent destruction and reutilization of heterologous dna applied to seeds of lactuca sativa [proceedings]. | 1977 | 79399 | |
| occupational dermatitis from lactuca sativa (lettuce) and cichorium (endive). simultaneous occurrence of immediate and delayed allergy as a cause of contact dermatitis. | four patients with occupational contact dermatitis to lactuca sativa had cross-sensitivity to cichorium endivia. one of the patients also had contact urticaria to lactuca and cichorium, and another reacted positively to scratch tests with these plants as a sign of immediate allergy. in two cases such immediate allergy was considered the cause of a vesicular, intense itching eruption within a few minutes of contact with fresh leaves of lactuca on previously eczematous skin. the severe chronic der ... | 1977 | 139283 |
| breaking of seed dormancy by catalase inhibition. | germination of some dormant seeds is promoted by solutions of thiourea, sodium nitrite, and hydroxylamine salts. the promotions are accompanied by irreversible inhibition of catalase (ec 1.11.1.6) in extracts from the seeds. the seeds are also promoted in germination by catechol and pyrogallol solutions. these effects are recorded for lettuce (lactuca sativa l. cv. grand rapids) and pigweed (amaranthus albus l.) seeds. the results indicae that metabolically derived hydrogen peroxide, spared from ... | 1977 | 235126 |
| [purification and characterization of chloroplast carbonate dehydratase from leaves of lactuca sativa (author's transl)]. | two isoenzymes of carbonate dehydratase were identified in green leaf tissue of lactuca sativa. their molecular weights were found to be 195 000 and 250 000. the lighter isoenzyme (i) was further characterized. it is localized in the chloroplast fraction. with polyacrylamide gel electrophoresis in the presence of dodecyl sulphate, subunits with a molecular weight of 34 000 and higher aggregates of this size could be detected. this is interpreted as an indication of an hexameric enzyme structure. ... | 1975 | 812792 |
| [biological effect of vibration on plants]. | the biological effect of vibration of lactuca sativa dry seeds and seedlings cultivated at optimal (20 degrees c) and suboptimal (4 degrees c) temperatures was studied. the effect of vibration slightly depended on its frequency (500-2000 hz). however, plant sensitivity to the exposure was related to their physiological state. vibration-induced disorders were transient, i.e. they returned to the normal rapidly enough. | 2012 | 824497 |
| light-induced de-epoxidation of violaxanthin in lettuce chloroplasts. iv. the effects of electron-transport conditions on violaxanthin availability. | 1. in isolated chloroplasts of lactuca sativa var. manoa, the size of the violaxanthin fraction which is available for de-epoxidation is not directly dependent on electron transport but rather related to the reduced level of some electron carrier between the photosystems. this is concluded from the effects of various electron-transport conditions on violaxanthin availability: under conditions of electron transport through both photosystems, availability was saturated at a lower electron-transpor ... | 1975 | 1125284 |
| [natural infection by broad bean wilt virus in head lettuce (lactuca sativa l.) (author's transl)]. | 1975 | 1242248 | |
| [presence of intestinal parasites in vegetables sold in the metropolitan region of são paulo, sp, brazil. i--search of helminths]. | vegetables in natura, commercially traded in the metropolitan area of s. paulo, were analysed by the appropriate methodology with a view to discovering an identifying the paths of transmission of enteroparasites of medical interest. the vegetables under study consisted of 50 samples of each variety listed below: lettuce (lactuca sativa)-oily leaves and crisphead varieties, endive (chicorium sp) and water-cress (nasturtium officinale). results showed high rates of contamination in all the vegetab ... | 1992 | 1342513 |
| [presence of intestinal parasites in vegetables sold in the metropolitan area of são paulo-sp, brazil. ii--research on intestinal protozoans]. | vegetables in nature, commercially traded in the metropolitan area of s. paulo, brazil, were analyzed by means of the appropriate methodology with a view to discovering and identifying protozoan cysts of medical interest. the vegetables under study consisted of 50 samples of each of the varieties listed below: lettuce (lactuca sativa)-oily leaves and crisp-head varieties, endive (chicorium sp) and watercress (nasturtium officinale). results showed high rates of contamination in all the varieties ... | 1992 | 1342522 |
| recent amplification of triose phosphate isomerase related sequences in lettuce. | a random cdna clone was identified as distinguishing near-isogenic lines for downy mildew resistance in lettuce. the clone detected multiple restriction fragments in genomic southern blots of lettuce. restriction fragment length polymorphisms (rflps) detected by this clone mapped to separate clusters of resistance genes; therefore, these sequences were studied in a greater detail. sequence analysis indicated that the cdna encoded the glycolytic enzyme triose phosphate isomerase (tpi). the lettuc ... | 1992 | 1356093 |
| dark induction of zeaxanthin-dependent nonphotochemical fluorescence quenching mediated by atp. | zeaxanthin-dependent nonphotochemical fluorescence quenching is a light-induced activity in plants that apparently protects against the potentially damaging effects of excess light. we report a dark-induced nonphotochemical quenching in thylakoids of lactuca sativa l. cv. romaine mediated by atp. this effect is due to low lumen ph from hydrolysis-dependent proton pumping and hence required an active atpase. the induction was optimal at 0.3 mm atp, a physiological concentration, and occurred unde ... | 1992 | 1542689 |
| glycosidic activities of candida albicans after action of vegetable latex saps (natural antifungals) and isoconazole (synthetic antifungal). | glycosidic activities have been examined in candida albicans grown on medium culture containing latex sap (natural antifungal) or isoconazole (synthetic antifungal). the different types of utilized latex sap were those of lactuca sativa (latex exuded from articulated laticifers) and asclepias curassavica (latex flowing from non-articulated laticifers). the same enzyme assays were performed on c. albicans grown without antifungal compounds. except for alpha-arabinosidase, all glycosidase activiti ... | 1991 | 1922192 |
| antifungal action of latex saps from lactuca sativa l. and asclepias curassavica l. | asclepias curassavica and lactuca sativa latex saps inhibit the growth of candida albicans because they degrade a great number of yeasts. this was confirmed by scanning and transmission electron microscopy observations. after a contact of 4 h and 6 h yeasts are deformed and emptied of their cytoplasmic content. moreover, it appears that these saps, particularly asclepias, also act on the cell wall: the substances presumed to be responsible for these effects were probably terpens and cardenolids ... | 1990 | 2090937 |
| mycoplasma lactucae sp. nov., a sterol-requiring mollicute from a plant surface. | strain 831-c4t (t = type strain), isolated from the surface of lettuce plants (lactuca sativa) obtained from a retail food market, was shown to be a sterol-requiring mollicute. morphological examination of this organism by electron and dark-field microscopic techniques showed that it consists of small, nonhelical, nonmotile, pleomorphic coccoid cells, with individual cells surrounded by a single cytoplasmic membrane. no evidence of a cell wall was observed. the organism grew rapidly in all conve ... | 1990 | 2223606 |
| [effect of outer space factors on lettuce seeds (lactuca sativa) flown on "kosmos" biosatellites]. | the effect of cosmic radiation on air-dry lettuce (lactuca sativa) seeds was investigated. it was attempted to discriminate the effects of cosmic ionizing radiation per se and its combination with solar light radiation. it was found that the number of aberrant cells in the seeds exposed to solar light was smaller than that of cells chielded with 0.0008 to 0.0035 g/cm2 foil which could be attributed to photoreactivity. | 2006 | 2329764 |
| [effect of single exposure of the seeds of lactuca sativa to heavy ions of galactic cosmic radiation at orbital manned space stations "saliut-6" and "saliut-7"]. | this paper presents the results of measuring single heavy ions (hi) of galactic cosmic rays during 40- to 457-day flights of manned orbital stations salyut-6 and salyut-7. cytogenetic analysis of lactuca sativa seeds showed a significant increase of aberrant cells and cells with multiple chromosome aberrations in seeds hit with hi compared to non-hit++ seeds during flights of 123 to 457 days in duration. there was a good correlation between curves showing aberrant cells as a function of flight o ... | 2006 | 2625981 |
| [combined effects of beta radiation and shock wave on the seeds of lettuce lactuca sativa l]. | the effect of shock wave (sw) and beta-radiation (beta) on lactuca sativa l. seeds was investigated. exposure to sw at an amplitude of 200 and 600 mpa in various combinations with beta caused a lower survival rate and development of abnormal plants. at an amplitude of 600 mpa, when the sw + beta protocol was used, the maximum amount of abnormalities was seen after 220-240 hours of wetting and when the beta + sw protocol was used the maximum amount of abnormalities was seen after 80-100 hours of ... | 2014 | 2716274 |
| isolation, molecular properties and kinetic studies of a strict beta-fucosidase from lactuca sativa latex. its possible role in the cell-wall degradation of articulated laticifers. | a beta-fucosidase located in the latex serum of lactuca sativa has been isolated and purified to homogeneity. this enzyme greatly differs from the other fucosidases already known in that it is strictly specific for the fucosyl residue and for the anomeric beta carbon. it is the first time that such an enzyme is shown to exist. the enzyme is a monomer and its molecular mass is close to 37 kda. its sedimentation constant is equal to 2.8 s. it is very stable at ph 5.5 in citrate/phosphate buffer bu ... | 2012 | 3409886 |
| the genetics of esterase isozymes in lactuca sativa l. | 1987 | 3435432 | |
| methyl mercury toxicity in plant cultures: modification of resistance and demethylation by light and/or 2,4-dichlorophenoxyacetic acid. | cultures of daucus carota, ca-68-10, and lactuca sativa, le-67, were grown at increasing methyl mercury (mehg) concentrations ranging from initial doses of 0.05 to 5.0 micrograms/ml per day for 4 days with or without 0.15 microgram/ml 2,4-dichlorophenoxyacetic acid (2,4-d) in the presence or absence of light. the presence of 2,4-d interacted with light synergistically in the expression of mehg toxicity within the whole range of concentrations. demethylation patterns increased or decreased depend ... | 1987 | 3595486 |
| polycyclic aromatic compounds (pac) in leaf lettuce. | twenty-three samples of leaf lettuce (lactuca sativa var. crispa) cultivated in private gardens in southern finland were analyzed for polycyclic aromatic hydrocarbons (pah) and derivatives. the total pah concentrations varied from 4.8 to 94 micrograms/kg fresh weight. nitro derivatives of pah were detected in only five samples. one lettuce sample was also analyzed for pah oxy-derivatives. 9h-fluoren-9-one (1.3 microgram/kg) and 6 h-benzo[cd]pyren-6-one (0.3 microgram/kg) were found. the profiles ... | 2013 | 3765856 |
| localization of chloroplastic fatty acid synthesis de novo in the stroma. | the synthesis of fatty acids de novo from [2-14c]malonyl-coa was studied in fractions from lettuce (lactuca sativa) and pea (pisum sativum) chloroplasts. when lettuce chloroplasts were subjected to osmotic lysis, disintegration through a yeda press and high-speed centrifugation, essentially all of the fatty-acid-synthetic activity was found to be soluble. the distribution of the activity in various chloroplast fractions was similar to that of soluble marker enzymes such as ribulose-1,5-bisphosph ... | 1985 | 3994672 |
| sidedness studies of thylakoid phosphatidylglycerol in higher plants. | the transmembrane distribution of phosphatidylglycerol was determined in thylakoids from barley (hordeum vulgare), lettuce (lactuca sativa) and pea (pisum sativum) chloroplasts. phospholipase a2 and phospholipase d digestion and chemical-labelling methods were used. phosphatidylglycerol was preferentially localized in the outer (stromal) leaflet. the proportion of the phospholipid in this leaflet ranged from about 66% in pea to about 75% for barley and lettuce thylakoids. one of the main fatty a ... | 1985 | 4026805 |
| [effect of heavy charged particles in galactic cosmic radiation on seeds]. | the experiments were carried out on lactuca sativa seeds exposed for 20, 66, 123 and 308 days in a biostack also containing physical detectors of heavy charged particles. the purpose of the experiments was to measure the yield of aberrant cells and its dependence on the exposure time and the site where particles hit the object. the cytogenetic examination demonstrated a significant difference between the seeds that were or were not hit by heavy charged particles. this is indicative of a signific ... | 2006 | 4033049 |
| [isolation and identification of the flavon(ol)glycosides of the endive (cichorium endivia l.) and the lettuce (lactuca sativa l.) (author's transl)]. | 2016 | 4277861 | |
| [an action spectrum of photomorphogenesis under high energy conditions and its interpretation on the basis of phytochrome (hypocotyl growth inhibition in lactuca sativa l)]. | 1967 | 4384903 | |
| phytochrome and temperature relations in lactuca sativa l. grand rapids seed germination after thermo-dormancy. | 1972 | 4621828 | |
| [morphological variability of myeoplasma-like bodies in the phloem of lactuca sativa l]. | 1972 | 4679140 | |
| biosynthesis of phytoquinones. homogentisic acid: a precursor of plastoquinones, tocopherols and alpha-tocopherolquinone in higher plants, green algae and blue-green algae. | 1. by means of (14)c tracer experiments and isotope competition experiments the roles of d-tyrosine, p-hydroxyphenylpyruvic acid, p-hydroxyphenylacetic acid, phenylacetic acid, homogentisic acid and homoarbutin (2-methylquinol 4-beta-d-glucoside) in the biosynthesis of plastoquinones, tocopherols and alpha-tocopherolquinone by maize shoots was investigated. it was established that d-tyrosine, p-hydroxyphenylpyruvic acid and homogentisic acid can all be utilized for this purpose, whereas p-hydrox ... | 1970 | 4986835 |
| [the effect of postradiation storage on the mutation process and germination of lettuce seeds (lactuca sativa) irradiated with co 60 gamma-rays]. | 2001 | 5052700 | |
| chemical form and physiological availability of iodine in lettuce (lactuca sativa). | 1967 | 6030612 | |
| the aster yellows controversy: current status. | evidence for and against the spiroplasmal etiology of aster yellows (ay) disease is examined. a spiroplasma, serologically identical to spiroplasma citri, was cultivated by some workers from lettuce (lactuca sativa l.) plants claimed to be naturally infected with ay. the isolated spiroplasma was shown to be infectious by injecting macrosteles fascifrons with the cultured organisms and then confining the injected leafhoppers on healthy plants. the reports claiming that a spiroplasma is the etiolo ... | 1983 | 6382826 |
| uptake of 2,4-d in higher plants from artificial rain. | sinapis alba l., lapsana communis l., achillea millefolium l., brassica napus l., lactuca sativa l., and lycopersicum esculentum l. were exposed to 2,4-dichlorophenoxy [2-14c]acetic acid (2,4-d) at 10 micrograms liter-1 in artificial rain, ph 6.5 and 3.3. the 2,4-d was absorbed in all species tested. concentrations of parent 2,4-d appeared at the highest level in achillea (0.1 mg kg-1 dry wt), and at zero level in lycopersicum. twenty-one daily treatments at ph 6.5 for 30-min periods increased d ... | 1984 | 6428858 |
| relative resistance of and delayed toxicity in undifferentiated plant cells to methyl mercury. | meristematic cells of carrot (daucus carota l., ca68-10) and lettuce (lactuca sativa l., le-67) cultured in 71-v medium (with 0.15 microgram/ml 2, 4-d) were given one initial dose (0.0001, 0.001, or 0.01 microgram/ml) of methyl mercury (mehg) at 0 hr, cultured for 288 hr. and then subcultured for 4 weeks. in another experiment, mehg was added in four daily doses (0.05, 0.10, 0.50, 1.0, 2.5, or 5.0 micrograms/ml) starting at 72 hr for 120 hr and then subcultured for 168 hr. the resulting 50% grow ... | 1984 | 6510322 |
| an evaluation of acetone extracts from six plants in the ames mutagenicity test. | acetone extracts from six plants were evaluated for mutagenic activity with the salmonella/mammalian-microsome mutagenicity test (ames) utilizing tester strains ta98 and ta100 and in the presence and absence of induced rat liver microsomes. extracts from alfalfa (medicago sativa), lettuce (lactuca sativa) and thread-leaf groundsel (senecio longilobus) produced only negative responses. comfrey (symphytum officinale) and tansy ragwort (senecio jacobaea) extracts produced toxic responses that were ... | 1983 | 6836587 |
| studies on herbal remedies i: analysis of herbal smoking preparations alleged to contain lettuce (lactuca sativa l.) and other natural products. | 1982 | 7062258 | |
| [cytogenetic effects in experimental exposure to the heavy charged particles of galactic cosmic radiation on the kosmos-1129 biosatellite]. | the experiment was carried out on lattice (lactuca sativa) seeds flown in a biocontainer equipped with plastic detectors to record heavy charged particles (hcp). the purpose of the experiment was to determine the yield of aberrant cells as a result of irradiation, and to identify this effect as a function of hcp topography in the seed. the cytogenetic examination of flight seedlings revealed a significant difference between the seeds which were hit with hcp and those that remained intact. this i ... | 2006 | 7120912 |
| the effect of phytohormones produced by arthrobacter sp. on the phosphatase activity in plant roots. | phytohormonal activity (auxins, gibberellins, cytokinins) was tested in the supernatant of a culture of arthrobacter sp. crude extract of the phytohormonal fraction was used as substrate for the growth of lactuca sativa seedlings. treating with bacterial hormones resulted in an increased plant develop- ment. furthermore, a sharp increase of the acid phosphatase activity was observed in the roots. | 1981 | 7262713 |
| [effect of aqueous extracts of tamus communis l. leaves on the germination of seeds of various species]. | the different influence of germination and growth inhibitors in aqueous extracts, at the same concentration, of tamus communis l. leaves, on germinating seeds and seedlings of nigra l., lactuca sativa l., medicago sativa l., has been shown. this action, very marked at the experimental concentrations, is not toxic, as the seeds and seedlings, if immersed in deionized water after treatments, recover their germination and growth. this recovery occurs however differently in the plants investigated. | 1981 | 7284097 |
| l-lactate dehydrogenase from leaves of higher plants. kinetics and regulation of the enzyme from lettuce (lactuca sativa l). | 1. l-lactate dehydrogenase from lettuce (lactuca sativa) leaves was purified to electrophoretic homogeneity by affinity chromatography. 2. in addition to its nad(h)-dependent activity with l-lactate and pyruvate, the enzyme also catalyses the reduction of hydroxypyruvate and glyoxylate. the latter activities are not due to a contamination of the enzyme preparations with hydroxypyruvate reductase. 3. the enzyme shows allosteric properties that are markedly by the ph. 4. atp is a potent inhibitor ... | 1981 | 7316976 |
| stabilization of adenine nucleotide ratios at various values by an oxygen limitation of respiration in germinating lettuce (lactuca sativa) seeds. | the concentrations of adenine nucleotides were determined in germinating lettuce (lactuca sativa) seeds after transitions from air to hypoxic or anoxic atmospheres. the ratio atp/adp and the energy charge were rapidly lowered after the transitions and remained stable at low values for hours. the energy charge in anoxia stabilized at a value close to 0.3. after 24 h in anoxia the energy charge rose rapidly to high values (0.9) when n2 was replaced by air. the metabolic properties of lettuce seeds ... | 1980 | 7447934 |
| effect of crop development on biogenic emissions from plant populations grown in closed plant growth chambers. | the biomass production chamber at john f. kennedy space center is a closed plant growth chamber facility that can be used to monitor the level of biogenic emissions from large populations of plants throughout their entire growth cycle. the head space atmosphere of a 26-day-old lettuce (lactuca sativa cv. waldmann's green) stand was repeatedly sampled and emissions identified and quantified using gc-mass spectrometry. concentrations of dimethyl sulphide, carbon disulphide, alpha-pinene, furan and ... | 1995 | 7669278 |
| influence of growth conditions on the value of crisphead lettuce. 4. quality changes during storage. | crisphead lettuce (lactuca sativa l. var capitata cvs. marius and saladin) were grown with a nitrogen supply from 50 to 200 kg n/hectare. heads were stored for one or two weeks at 1 degree c in cold storage or ice bank cooling. samples were taken for measurement of dry matter, sugars, vitamin c and nitrate. the content of dry matter, sugars (glucose, fructose) and vitamin c decreased with increasing level of nitrogen, and the content of nitrate increased. except for nitrate the contents of the o ... | 1995 | 7792264 |
| a lactuca universal hybridizer, and its use in creation of fertile interspecific somatic hybrids. | a lactuca sativa cv. ardente line heterozygous for a gene encoding resistance to kanamycin, a positive and dominant trait, was crossed with cv. girelle, which is heterozygous for a recessive albinism marker. the resulting seeds yielded 25% albino seedlings, of which 50% were also resistant to kanamycin. such plantlets (kr, a) grown in vitro were used for preparation of universal hybridizer protoplasts, since green buds that can develop on kanamycin containing-medium should result from fusion wit ... | 1994 | 7816020 |
| analysis of a detailed genetic linkage map of lactuca sativa (lettuce) constructed from rflp and rapd markers. | a detailed genetic map has been constructed from the f2 population of a single intraspecific cross of lactuca sativa (n = 9). it comprises 319 loci, including 152 restriction fragment length polymorphism (rflp), 130 random amplified polymorphic dna (rapd), 7 isozyme, 19 disease resistance, and 11 morphological markers. thirteen major, four minor linkage groups and several unlinked markers are identified for this genome which is estimated to be approximately 1950 cm. rflp and rapd markers show si ... | 1994 | 7912217 |
| lettuce and carrot allergy: are they related? | lettuce is commonly included in many elimination diets of subjects with either food allergy or atopic dermatitis since ige-mediated allergic reactions have not been reported. we have observed a positive carrot skin test and/or rast in two clinically lettuce sensitive, ragweed allergic subjects and positive lettuce skin test and/or rast in two ragweed allergic patients with oral allergy syndrome to carrot. in this study lettuce allergy and the allergenic relationship between iceberg lettuce (lact ... | 2004 | 8005454 |
| mutants of downy mildew resistance in lactuca sativa (lettuce). | as part of our investigation of disease resistance in lettuce, we generated mutants that have lost resistance to bremia lactucae, the casual fungus of downy mildew. using a rapid and reliable screen, we identified 16 distinct mutants of latuca sativa that have lost activity of one of four different downy mildew resistance genes (dm). in all mutants, only a single dm specificity was affected. genetic analysis indicated that the lesions segregated as single, recessive mutations at the dm loci. dm3 ... | 1994 | 8088530 |
| phytogrowth-inhibitory activities of 2-thiophenecarboxylic acid and its related compounds. | 2-thiophenecarboxylic acid (i) exhibited growth-inhibitory activity in five kinds of plants. in particular, i strongly inhibited the growth of the roots of lactuca sativa l. var. longifolia lam and echinochloa utilis ohwi et yabuno, even at the low concentration of 5.0 x 10(-3) m. furthermore, all of the i-related compounds (ii-v and vii-x) except for vi, showed more or less obvious inhibitory activity on the seeds of sesamum indicum l. compounds vii-x, in which the carboxyl group of i was repla ... | 1994 | 8148810 |
| intron loss from the nadh dehydrogenase subunit 4 gene of lettuce mitochondrial dna: evidence for homologous recombination of a cdna intermediate. | the mitochondrial gene coding for subunit 4 of the nadh dehydrogenase complex i (nad4) has been isolated and characterized from lettuce, lactuca sativa. analysis of nad4 genes in a number of plants by southern hybridization had previously suggested that the intron content varied between species. characterization of the lettuce gene confirms this observation. lettuce nad4 contains two exons and one group iia intron, whereas previously sequenced nad4 genes from turnip and wheat contain three group ... | 1994 | 8190077 |
| transactivation of ds elements in plants of lettuce (lactuca sativa). | the maize transposable element, activator (ac), is being used to develop a transposon mutagenesis system in lettuce, lactuca sativa. in this paper, we describe somatic and germinal transactivation of ds by chimeric transposase genes in whole plants. constructs containing either the ds element or the ac transposase open reading frame (orf) were introduced into lettue. the ds element was located between either the 35s or the nos promoter and a chimeric spectinomycin resistance gene (which included ... | 1993 | 8246892 |
| infrequent transposition of ac in lettuce, lactuca sativa. | the maize transposable element activator (ac) is being used to develop a transposon mutagenesis system in lettuce, lactuca sativa. two constructs containing the complete ac from the waxy-m7 locus of maize were introduced into lettuce and monitored for activity using southern analysis and pcr amplification of the excision site. no transposition of ac was detected in over 32 transgenic r1 plants, although these constructs were known to provide frequent transposition in other species. also, no tran ... | 1993 | 8395257 |
| simple chromatographic systems permitting both dna purification and separation of 2'-deoxyribonucleoside 3'-monophosphates as substrates for 32p-postlabelling studies. | the 32p-postlabelling method has recently been applied to the measurement of oxidative dna damage. the assay requires the isolation of 2'-deoxyribonucleoside 3'-monophosphates subsequent to the extraction of dna followed by its enzymatic digestion. as an alternative to the use of toxic and oxidizing solvents such as phenol, a simple purification method is proposed, based mainly on size-exclusion chromatography carried out either with ready-made columns (nap-10, sec-2000) or, more conveniently, w ... | 1993 | 8491811 |
| anti-hyperglycemic effect of some edible plants. | the anti-hyperglycemic effect of 12 edible plants was studied on 27 healthy rabbits, submitted weekly to subcutaneous glucose tolerance tests after gastric administration of water, tolbutamide or a traditional preparation of the plant. tolbutamide, cucurbita ficifolia, phaseolus vulgaris, opuntia streptacantha, spinacea oleracea, cucumis sativus and cuminum cyminum decrease significantly the area under the glucose tolerance curve and the hyperglycemic peak. brassica oleracea var. botrytis, alliu ... | 1995 | 8569244 |
| molecular analysis of irradiation-induced and spontaneous deletion mutants at a disease resistance locus in lactuca sativa. | the major cluster of disease resistance genes in lettuce (lactuca sativa) contains at least nine downy mildew resistance genes (dm) spanning a genetic distance of 20cm and a physical distance of at least 6 mb. nine molecular markers that were genetically tightly linked to dm3 were used to analyze nine independent deletion mutants and construct a map of the region surrounding dm3. this analysis identified a linear order of deletion breakpoints and markers along the chromosome. there was no eviden ... | 1996 | 8676874 |
| violaxanthin de-epoxidase. | violaxanthin de-epoxidase catalyzes the de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin in the xanthophyll cycle. its activity is optimal at approximately ph 5.2 and requires ascorbate. in conjunction with the transthylakoid ph gradient, the formation of antheraxanthin and zeaxanthin reduces the photochemical efficiency of photosystem ii by increasing the nonradiative (heat) dissipation of energy in the antennae. previously, violaxanthin de-epoxidase had been partially purified. ... | 1996 | 8742341 |
| rhizobium leguminosarum as a plant growth-promoting rhizobacterium: direct growth promotion of canola and lettuce. | early seedling root growth of the nonlegumes canola (brassica campestris cv. tobin, brassica napus cv. westar) and lettuce (lactuca sativa cv. grand rapids) was significantly promoted by inoculation of seeds with certain strains of rhizobium leguminosarum, including nitrogen- and nonnitrogen-fixing derivatives under gnotobiotic conditions. the growth-promotive effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. auxotrophic rhi ... | 1996 | 8868235 |
| inhalative occupational and ingestive immediate-type allergy caused by chicory (cichorium intybus). | we report a first case of occupational allergy to chicory (cichorium intybus) in a vegetable wholesaler. symptoms occurred after oral, cutaneous or inhalatory exposure. the patient also reported reactions after ingestion of botanically related endive (cichorium endivia) and lettuce (lactuca sativa). we identified the responsible allergen by sds-page and immunoblot to be a 48-kda protein, confined to the non-illuminated parts of the plants. no cross-reactivity was found with mugwort (artemisia vu ... | 1996 | 8877160 |
| molecular and functional characterization of slide, an ac-like autonomous transposable element from tobacco. | a new transposable element of tobacco, slide, was isolated from the tl mutant line, which shows somatic instability, after its transposition into a locus encoding nitrate reductase (nr). the slide-124 element is 3733 bp long and its coding sequences show similarities with conserved domains of the transposases of ac, tam3 and hobo. excision from the nr locus is detectable in somatic leaf tissues and slide mobility is triggered by in vitro tissue culture. slide excision events create footprints si ... | 1996 | 8879239 |
| activation of aniline by extracts from plants and induction of chromosomal damages in chinese hamster ovary cells. | activation of aniline by plant extracts was studied by a chromosomal damage induction assay in chinese hamster ovary (cho) cells in vitro. extracts from roots of vicia faba activated aniline and the activation caused increases in chromosomal aberrations (cas) and endoreduplicated cells (ercs), but did not cause sister-chromatid exchanges (sces). extracts from pisum sativum and lactuca sativa, however, did not activate aniline. all c-hydroxylated metabolites of aniline, o-aminophenol, m-aminophen ... | 1996 | 9037777 |
| kinetic study of the suicide inactivation of latent polyphenoloxidase from iceberg lettuce (lactuca sativa) induced by 4-tert-butylcatechol in the presence of sds. | in plants, polyphenoloxidase undergoes an irreversible inactivation during the oxidation of o-diphenol to o-quinones. in the present paper, using latent polyphenoloxidase from iceberg lettuce (lactuca sativa), in the presence of an activating agent, sds, the kinetic parameters that characterize the enzyme during its action on the suicide substrate 4-tert-butylcatechol have been determined. the effect of ph has also been considered. it was seen that the presence of sds in the reaction medium chan ... | 1997 | 9187250 |
| a transgenic mutant of lactuca sativa (lettuce) with a t-dna tightly linked to loss of downy mildew resistance. | one hundred and ninety-two independent primary transformants of lettuce cv. diana were obtained by co-cultivation with agrobacterium tumefaciens carrying constructs containing maize ac transposase and ds. r2 families were screened for mutations at four genes (dm) for resistance to downy mildew. one family, designated dm3t524, had lost resistance to an isolate of bremia lactucae expressing the avirulence gene avr3. loss of resistance segregated as a single recessive allele of dm3. the mutation wa ... | 1997 | 9353944 |
| regulation of thermal dissipation of absorbed excitation energy and violaxanthin deepoxidation in the thylakoids of lactuca sativa. photoprotective mechanism of a population of photosystem ii centers | non-photochemical quenching of chlorophyll a fluorescence is thought to be mainly associated with thermal dissipation of excitation energy taking place within the antenna and reaction center of ps ii. in this report, non-photochemical fluorescence quenching was investigated in the fluorescence yields induced by a series of short and high-energy flashes after dark adaptation. the observation of period four fluorescence oscillations with increasing flash number indicates functioning o2 evolving ce ... | 1998 | 9507102 |
| occupational dermatitis in danish gardeners and greenhouse workers (iii). compositae-related symptoms. | the clinical part of the study aimed at describing epidemiological and diagnostic aspects of occupational compositae dermatitis. patch testing with the sesquiterpene lactone (sl) and compositae mixes, feverfew extract and supplementary allergens in 250 selected gardeners showed compositae allergy in 25, 17 females and 8 males. 24 were possibly occupationally sensitized. the mean age was lower and the preponderance of women higher compared to classical compositae dermatitis, and the distribution ... | 1998 | 9536405 |
| identification of a 37 kda plant protein that interacts with the turnip mosaic potyvirus capsid protein using anti-idiotypic-antibodies. | experimental data are provided for the presence of a plant protein that interacts with the capsid protein (cp) of turnip mosaic potyvirus (tumv). the receptor-like protein was identified by exploiting the molecular mimicry potential of anti-idiotypic antibodies. a single-chain fv molecule derived from the monoclonal antibody 7a (mab-7a), which recognizes the cp of tumv, was produced in escherichia coli and the recombinant protein was used to raise rabbit antibodies. the immune serum reacted with ... | 1998 | 9617793 |
| assessment of the transfer of 137cs in three types of vegetables consumed in hong kong. | a dynamic food chain model has been built for the modeling of the transfer of 137cs in three types of vegetables consumed in hong kong, namely, white flowering cabbage (brassica chinensis), head lettuce (lactuca sativa) and celery (apium graveolens). some parameters have been estimated from the experimental data obtained in this work. the experimental data include the transfer factors of 137cs from soil to the different vegetable species which are determined through high resolution gamma spectro ... | 1998 | 9745700 |
| study of a case of hypersensitivity to lettuce (lactuca sativa). | allergic reactions to lettuce (lactuca sativa) are not too frequent and few cases of systemic adverse reactions after its ingestion have been described. | 1998 | 9756210 |
| localized changes in peroxidase activity accompany hydrogen peroxide generation during the development of a nonhost hypersensitive reaction in lettuce | peroxidase activity was characterized in lettuce (lactuca sativa l.) leaf tissue. changes in the activity and distribution of the enzyme were examined during the development of a nonhost hypersensitive reaction (hr) induced by pseudomonas syringae (p. s.) pv phaseolicola and in response to an hrp mutant of the bacterium. assays of activity in tissue extracts revealed ph optima of 4.5, 6.0, 5.5 to 6.0, and 6.0 to 6.5 for the substrates tetramethylbenzidine, guaiacol, caffeic acid, and chlorogenic ... | 1998 | 9808752 |
| phytochrome regulates gibberellin biosynthesis during germination of photoblastic lettuce seeds. | germination of lettuce (lactuca sativa l.) seed is regulated by phytochrome. the requirement for red light is circumvented by the application of gibberellin (ga). we have previously shown that the endogenous content of ga1, the main bioactive ga in lettuce seeds, increases after red-light treatment. to clarify which step of ga1 synthesis is regulated by phytochrome, cdnas encoding ga 20-oxidases (ls20ox1 and ls20ox2, for l. sativa ga 20-oxidase) and 3beta-hydroxylases (ls3h1 and ls3h2 for l. sat ... | 1998 | 9847128 |
| microsatellite retrieval in lettuce (lactuca sativa l.). | by using enriched genomic libraries, microsatellite-containing sequences were isolated from lettuce (lactuca sativa) with high efficiency. with this approach, a sizeable fraction (up to 55%) of the clones contained a microsatellite. in about half of these clones, primers could be designed for pcr amplification of the microsatellite. this yielded 28 primer sets amplifying unambiguously scorable products, of which 26 showed polymorphisms in a test set of six lettuce varieties. practically all micr ... | 1999 | 10208007 |
| postharvest analysis of vitamin c and inorganic cations in lettuce by cze. | in the present work, we used capillary zone electrophoresis (cze) for the analysis of vitamin c and inorganic cations (potassium, sodium, calcium, and magnesium) in lettuce (lactuca sativa) during postharvest storage. the leaves of the creasphead lettuce samples were treated with 18 m omega water for cation analysis and, alternatively, with 3% wt/vol oxalic acid solution for ascorbic acid extraction. they were then homogenized and centrifuged, and the supernatants were introduced into the capill ... | 2013 | 10327371 |
| mapping morphological genes relative to molecular markers in lettuce (lactuca sativa l.) | two f2 populations were generated by crossing morphologically diverse genetic stocks in order to map 10 morphological traits relative to polymerase chain reaction-based molecular markers (rapds). using one segregating population generated from crossing the experimental line, 'dwarf-2', with the butterhead cultivar, 'saffier', the dwarf phenotype conditioned by the dwf2 locus was mapped using bulked segregation analysis to within 38 cm of the adh3 locus. using the second segregating population ge ... | 1999 | 10336698 |
| toxicity of formulated glycol deicers and ethylene and propylene glycol to lactuca sativa, lolium perenne, selenastrum capricornutum, and lemna minor | laboratory studies were conducted to determine the toxicity of ethylene glycol (eg) and propylene glycol (pg) as well as two formulated glycol aircraft deicing/anti-icing fluids (adafs) to lettuce (lactuca sativa), perennial ryegrass (lolium perenne), a green alga (selenastrum capricornutum), and duckweed (lemna minor). seedling emergence, root length, and shoot length were measured in lettuce and ryegrass; cell growth of the alga and frond growth, chlorophyll a, and pheophytin a of the duckweed ... | 1999 | 10341039 |
| retention of microcystis aeruginosa and microcystin by salad lettuce (lactuca sativa) after spray irrigation with water containing cyanobacteria. | colonies and single cells of microcystis aeruginosa and the hepatotoxin microcystin were retained by salad lettuce after growth with spray irrigation water containing the microcystin-producing cyanobacteria. these findings are discussed in terms of crop spray irrigation with water containing cyanobacteria and potential human exposure to cyanobacterial toxins via plant foods grown in such circumstances. | 1999 | 10400301 |
| phytotoxic lignans of leucophyllum frutescens. | bioassay-guided fractionation of the hexane:ethyl acetate (1:1) extract of the leaves of leucophyllum frutescens (berl.) i.m.johnst (scrophulariaceae) led to the isolation of its phytotoxic constituents diayangambin (1), epiyangambin (2), diasesartemin (3) and epiashantin (4). phytotoxicity was demonstrated as inhibition of seed germination of agrostis stolonifera cv. penncross (poaceae) and inhibition of development of lactuca sativa l. (asteraceae) seedlings in a microassay using 24-well plate ... | 1999 | 10441036 |
| determination of ametryn herbicide by bioassay and gas chromatography-mass spectrometry in analysis of residues in drinking water. | a simple, rapid and quantitative bioassay method was compared to a gas chromatography/mass spectrometry (gc/ms) procedure for the analysis of ametryn in surface and groundwater. this method was based on the activity of ametryn in inhibiting the growth of the primary root and shoot of germinating letuce, lactuca sativa l. seed. the procedure was sensitive to 0.01 microgram/l and was applicable from this concentration up to 0.6 microgram/l. initial surface sterilization of the seed, selection of p ... | 1999 | 10464973 |
| [the enteroparasitic contamination of commercial vegetables in the cities of niterói and rio de janeiro, brazil]. | the aim of this study was to evaluate the parasitological contamination of vegetables to be consumed raw and commercialized in niterói and rio de janeiro cities. we studied 128 samples of vegetables--lettuce (lactuca sativa) and watercress (nasturtium officinale)--from supermarkets, greengrocer shops and self-service restaurants. only 6.2% of the samples were positive for parasitic structures with morphological aspects similar to those of animal parasites. we detected acarids, acarid eggs, insec ... | 1999 | 10495664 |
| [in process citation] | this study focuses on how allelopathic mechanisms may be involved in the floristic composition and dynamics of cistus albidus shrubbery. allelopathic potential of essential oils was measured for lactuca sativa (toxicity for other species) and cistus albidus (self-toxicity). these oils have little effect on germination but significantly increase, even in low quantities, the number of unviable seedlings and inhibit normal seedling growth. these results explain, at least partially, the existence of ... | 1999 | 10505240 |
| a plant-derived edible vaccine against hepatitis b virus. | the infectious hepatitis b virus represents 42 nm spherical double-shelled particles. however, analysis of blood from hepatitis b virus carriers revealed the presence of smaller 22 nm particles consisting of a viral envelope surface protein. these particles are highly immunogenic and have been used in the design of hepatitis b virus vaccine produced in yeast. upon expression in yeast, these proteins form virus-like particles that are used for parenteral immunization. therefore, the dna fragment ... | 1999 | 10506582 |
| characterization of monophenolase activity of polyphenol oxidase from iceberg lettuce. | polyphenol oxidase (ec 1.14.18.1), a thylakoid membrane-bound enzyme, was isolated by sonication of osmotically shocked chloroplasts from iceberg lettuce (lactuca sativa). the enzyme showed monophenolase activity when assayed on (p-hydroxyphenyl)propionic acid with 3-methyl-2-benzothiazolinone hydrazone in a reliable continuous spectrophotometric method, with high sensitivity, accuracy, and precision. the monophenolase activity showed a lag period before the steady-state rate (v(ss)) was reached ... | 1999 | 10563992 |
| nitric oxide stimulates seed germination and de-etiolation, and inhibits hypocotyl elongation, three light-inducible responses in plants. | seed germination, greening of etiolated plants and inhibition of hypocotyl elongation are stimulated by light, which is sensed by various types of photoreceptor. nitric oxide (no) has proven to be a bioactive molecule, especially in mammalian cells and, most recently, in plants. like some phytochrome-dependent processes, many no-mediated ones are accomplished through increases in cgmp levels. given these similarities, we proposed that no could take part in light-mediated events in plants. here w ... | 2000 | 10664127 |
| identification of multi-gene families encoding isopentenyl diphosphate isomerase in plants by heterologous complementation in escherichia coli. | two cdnas encoding isopentenyl diphosphate isomerase (ipi) in adonis aestivalis, arabidopsis thaliana, and lactuca sativa, and single examples from oryza sativa and tagetes erecta were identified. an analysis of these and other ipi leads us to suggest a separate origin for green algal and plant genes and propose that a single gene encodes plastid and cytosolic ipi in plants. | 2000 | 10750717 |
| metabolite profiling of sesquiterpene lactones from lactuca species. major latex components are novel oxalate and sulfate conjugates of lactucin and its derivatives. | wounding leaves or stems of lactuca species releases a milky latex onto the plant surface. we have examined the constituents of latex from lactuca sativa (lettuce) cv. diana. the major components were shown to be novel 15-oxalyl and 8-sulfate conjugates of the guaianolide sesquiterpene lactones, lactucin, deoxylactucin, and lactucopicrin. the oxalates were unstable, reverting to the parent sesquiterpene lactone on hydrolysis. oxalyl derivatives have been reported rarely from natural sources. the ... | 2000 | 10858433 |
| inhibition of plant asparagine synthetase by monoterpene cineoles. | asparagine (asn) synthetase (as) is the key enzyme in asn biosynthesis and plays an important role in nitrogen mobilization. despite its important physiological function, little research has been done documenting inhibitors of plant as. plant growth inhibition caused by the natural monoterpene 1,4-cineole and its structurally related herbicide cinmethylin was reversed 65% and 55%, respectively, by providing 100 microm asn exogenously. reversion of the phytotoxic effect was dependent on the conce ... | 2000 | 10859202 |
| natural and synthetic podolactones with potential use as natural herbicide models. | a collection of 11 natural and synthetic podolactones have been tested as allelochemicals in a range between 10(-4) and 10(-9) m, and their potential use as natural herbicide models is discussed. their effects on the germination and growth of the dicots lactuca sativa (cv. nigra and cv. roman), lepidium sativum, and lycopersicon esculentum and the monocots allium cepa, hordeum vulgare, and triticum aestivum as standard target species have been studied. an important inhibitory effect on the germi ... | 2000 | 10898656 |
| impact of insecticides and surfactant on lettuce physiology and yield. | insecticides are used extensively on lettuce, lactuca sativa l., grown in southwestern arizona because of heavy insect pressure that can potentially reduce lettuce productivity. multiple sprays are made per season to manage these insects in lettuce. one of the major concerns related to extensive insecticide applications in lettuce is the potential subtle impact of insecticides that may reduce lettuce photosynthesis and yield. we conducted field and greenhouse experiments to examine the impact of ... | 2000 | 10902331 |
| cantaloupe melon peroxidase: characterization and effects of additives on activity. | peroxidase in cantaloupe melon (cucumis melo l. var. reticulatus naud.), a fruit commonly fresh cut processed, was characterized to determine reaction pathway, optimal conditions for activity and effect of some additives on enzymatic action. mn2+, cacl2, nano2 and kinetin had partial inhibitory effects on enzyme activity. activity was effectively inhibited by compounds capable of chelating peroxidase heme iron such as diethyldithiocarbamate and tiron, but unaffected by edta. free radical scaveng ... | 2000 | 10907237 |
| inactivation of dna replication origins by the cell cycle regulator, trigonelline, in root meristems of lactuca sativa. | the effects of trigonelline (trg) on the cell cycle in root meristems of lactuca sativa l. were examined in the knowledge that trg is a cell cycle regulator that causes cell arrest in g2, and prevents ligation of replicons in s-phase. the hypothesis was tested that continuous exposure to trg would perturb dna replication which, in turn, would lengthen the cell cycle and impair root elongation. using dna fibre autoradiography, mean replicon size was 31 and 13 microm in the trg (3 mm) and control ... | 2000 | 10923713 |
| growth promoting effect of two sinorhizobium meliloti strains (a wild type and its genetically modified derivative) on a non-legume plant species in specific interaction with two arbuscular mycorrhizal fungi. | in the present study, we have investigated whether the ubiquitous rhizosphere soil organism sinorhizobium meliloti has a plant growth promoting (pgp) effect on non-leguminous plant species. such pgp activity was investigated for both a wild type strain and its genetically modified (gm) derivative, which had an enhanced biofertilizer capability. the pgp effect of these rhizobial strains was tested in interaction with two arbuscular-mycorrhizal (am) fungi: g. mosseae or g. intraradices on lettuce ... | 2000 | 11011093 |
| a comparison of peronospora parasitica (downy mildew) isolates from arabidopsis thaliana and brassica oleracea using amplified fragment length polymorphism and internal transcribed spacer 1 sequence analyses. | amplified fragment length polymorphism (aflp) fingerprints and internal transcribed spacer 1 (its1) sequences from 27 peronospora parasitica isolates (collected from arabidopsis thaliana or brassica oleracea), 5 albugo candida isolates (from the same hosts and from capsella bursa-pastoris), and 1 bremia lactucae isolate (from lactuca sativa) were compared. the aflp analysis divided the isolates into five groups that correlated with taxonomic species and, in most cases, with host origin. the only ... | 2000 | 11017765 |
| quantification of metal bioavailability for lettuce (lactuca sativa l.) in field soils. | understanding metal bioavailability of plants in soils requires, apart from physiological processes and symbiosis with arbuscular mycorrhizal fungi, the consideration of the chemical availability in the soil solution (the intensity of the toxic exposure) and the soil's capacity to supply the metal (capacity). in this contribution we report on the time-dependent accumulation of as, cd, cr, cu, ni, pb, and zn in lettuce (lactuca sativa l.). bioassays with 17 dutch field soils and two artificially ... | 2000 | 11031301 |
| classical and biochemical endpoints in the evaluation of phytotoxic effects caused by the herbicide trichloroacetate. | three terrestrial plant species, oat (avena sativa ), chinese cabbage (brassica campestris cv. chinensis) and lettuce (lactuca sativa), were exposed to different concentrations of herbicide tca (sodium trichloroacetate) in a growth test according to guideline oecd # 208. classical (i.e. germination and biomass) and biochemical (i.e., antioxydant enzyme activities) endpoints were investigated. germination rate decreased significantly at 3.9 mg tca kg dry soil(-1) (for oat and lettuce) and 62.5 mg ... | 2000 | 11064042 |
| the action spectrum for maximal photosensitivity of germination. | fruits of garden lettuce, imbibed in 0.01 m kno3, were depleted of maternal active phytochrome b by saturating deep-red exposure and photosensitized by chilling for 1 week at 4 degrees c. twenty saturated fluence-response curves for photoinduced germination were elaborated between 300 and 800 nm, using exposure periods from 6 to 600 s at 22.5 degrees c; there is linear and closely parallel regression in the logarithmic probability net. the reciprocals of the half-response fluences obtained gave ... | 2000 | 11091963 |
| abscisic acid and hypoxic induction of anoxia tolerance in roots of lettuce seedlings. | lettuce (lactuca sativa l.) seedlings were subjected to anoxic stress after aba-pretreatment (aba-pt) or hypoxic-pretreatment (h-pt). the h-pt increased the survivability of the anoxia in roots of the seedlings by 5.2-fold compared to that of non-pretreated (n-pt) seedlings. aba-pt also increased the survivability at concentrations greater than 1 microm, and the survivability increased with increasing aba doses. at 100 microm aba, the survivability was 4.5-fold greater than that of n-pt seedling ... | 2000 | 11113172 |
| recombination and spontaneous mutation at the major cluster of resistance genes in lettuce (lactuca sativa). | two sets of overlapping experiments were conducted to examine recombination and spontaneous mutation events within clusters of resistance genes in lettuce. multiple generations were screened for recombinants using pcr-based markers flanking dm3. the dm3 region is not highly recombinagenic, exhibiting a recombination frequency 18-fold lower than the genome average. recombinants were identified only rarely within the cluster of dm3 homologs and no crossovers within genes were detected. three popul ... | 2001 | 11157000 |
| effect of wounding on phenolic enzymes in six minimally processed lettuce cultivars upon storage. | the effect of wounding on polyphenol oxidase (ppo), peroxidase (pod), and phenylalanine ammonia-lyase (pal) was studied in six minimally processed lettuce (lactuca sativa l.) cultivars upon storage for 7 days at 5 degrees c (iceberg mikonos (im), i. green queen (igq), i. asdrúbal (ia), little gem sandra (lgs), romaine cazorla (rc), and r. modelo (rm)). wounding of lettuce tissue midribs (because of minimal processing) caused an exponential increase in ppo activity due to the activation process f ... | 2001 | 11170594 |
| preparation and biological activity of four epiprogoitrin myrosinase-derived products. | (5r)-5-vinyl-1,3-oxazolidine-2-thione, (2s)-1-cyano-2-hydroxy-3-butene, and two diastereoisomeric erythro-(2s)- and threo-(2s)-1-cyano-2-hydroxy-3,4-epithiobutanes were prepared in pure form starting from (2s)-2-hydroxybut-3-enyl glucosinolate (epiprogoitrin). this glucosinolate was isolated in almost pure form using ripe seeds of crambe abyssinica and then hydrolyzed under different conditions. the hydrolysis was carried out using either myrosinase immobilized on nylon, to produce (5r)-5-vinyl- ... | 2001 | 11170613 |
| one ring or two? determination of ring number in carotenoids by lycopene epsilon-cyclases. | carotenoids in the photosynthetic membranes of plants typically contain two beta-rings (e.g., beta-carotene and zeaxanthin) or one epsilon- and one beta-ring (e.g., lutein). carotenoids with two epsilon-rings are uncommon. we reported earlier that the arabidopsis thaliana lycopene epsilon-cyclase (lcye) adds one epsilon-ring to the symmetrical linear substrate lycopene, whereas the structurally related lycopene beta-cyclase (lcyb) adds two beta-rings. here we describe a cdna encoding lcye in rom ... | 2001 | 11226339 |
| responses of plant growth rate to nitrogen supply: a comparison of relative addition and n interruption treatments. | this paper investigates the effects of uptake of nitrate and the availability of internal n reserves on growth rate in times of restricted supply, and examines the extent to which the response is mediated by the different pools of n (nitrate n, organic n and total n) in the plant. hydroponic experiments were carried out with young lettuce plants (lactuca sativa l.) to compare responses to either an interruption in external n supply or the imposition of different relative n addition rate (rar) tr ... | 2001 | 11283176 |
| assessment of toxicity reduction after metal removal in bioleached sewage sludge. | sewage sludge can be applied to land to supply and recycle organic matter and nutrients. trace elements in sludge, however, may accumulate in the soil with repeated sludge applications. reducing metal content may therefore reduce the adverse effects of sludge application. the objective of this study was to evaluate the efficiency of bioleaching technology in reducing metal content and toxicity as measured by a battery of terrestrial and liquid-phase bioassays. sludge-soil mixtures simulating the ... | 2001 | 11317888 |
| interlaboratory study for the validation of an ecotoxicological procedure to monitor the quality of septic sludge received at a wastewater treatment plant. | septic tank sludge is regularly hauled to the montreal urban community (muc) wastewater treatment plant. it is then discharged and mixed with the wastewater inflow before entering the primary chemical treatment process. an ecotoxicological procedure integrating chemical and toxicological analyses has been recently developed and applied to screen for the illicit discharge of toxic substances in septic sludge. the toxicity tests used were the microtox, the bacterial-respiration, and the lettuce (l ... | 2001 | 11339716 |