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variations in bioactive substance contents and crop yields of lettuce (lactuca sativa l.) cultivated in soils with different fertilization treatments.changes in crop yields and bioactive substance contents were studied in lettuce crop concerning the influence of soil nutritional status as a result of compost and vermicompost additions obtained from different organic substrates. plant productions and main pigment contents in lettuce were higher in all the fertilized soils than in the untreated soil, with the exception of the one treated with urban solid waste compost. these positive effects correlate with nitrogen level increase in soil. howev ...200919821565
lack of internalization of escherichia coli o157:h7 in lettuce (lactuca sativa l.) after leaf surface and soil inoculation.survival and internalization characteristics of escherichia coli o157:h7 in iceberg, romaine, and leaf lettuce after inoculation of leaf surfaces and soil were determined. a five-strain mixture of e. coli o157:h7 in water and cow manure extract was used as an inoculum for abaxial and adaxial sides of leaves at populations of 6 to 7 log and 4 log cfu per plant. the five strains were individually inoculated into soil at populations of 3 and 6 log cfu/g. soil, leaves, and roots were analyzed for th ...200919833024
rin4 causes hybrid necrosis and race-specific resistance in an interspecific lettuce hybrid.some inter- and intraspecific crosses may result in reduced viability or sterility in the offspring, often due to genetic incompatibilities resulting from interactions between two or more loci. hybrid necrosis is a postzygotic genetic incompatibility that is phenotypically manifested as necrotic lesions on the plant. we observed hybrid necrosis in interspecific lettuce (lactuca sativa and lactuca saligna) hybrids that correlated with resistance to downy mildew. segregation analysis revealed a sp ...200919855048
[agrobacterium-mediated transformation of lettuce (lactuca sativa l.) with vectors bearing genes of bacterial antigenes from mycobacterium tuberculosis].transgenic plants of lettuce lactuca sativa l. cv. eralash, sniezinka, rubinovoje kruzevo with genes coding synthesis of tuberculosis antigenes have been obtained by agrobacterium-mediated transformation. cotyledons of in vitro seedlings were used as the initial material for transformation with plasmids pcb063 (genes esat6, nptii) and pcb064 (genes esat6:ag85b(-tmd), nptii). pcr-analysis has shown the presence both selective and target genes in all plants analyzed. at the same time, the rt-pcr h ...200919938623
heat and drought stress during growth of lettuce (lactuca sativa l.) does not promote internalization of escherichia coli o157:h7.studies were done to determine the effect of heat stress on internalization of escherichia coli o157:h7 in lettuce subjected to different watering practices during growth. iceberg and romaine lettuce were grown in sandy soil in an environmental chamber at 23 degrees c during the day and 7 degrees c at night, with a 12-h photoperiod. thirty days after transplanting seedlings, potting soil was inoculated with a five-strain mixture of green fluorescent protein-labeled e. coli o157:h7 at populations ...200920003727
[bio-objects and biological methods of space radiation effects evaluation].the unique conditions of space experiments place austere requirements to bio-objects and biological methods of radiation effects evaluation. the paper discusses suitability of a number of bio-objects varying in stage of evolution and metabolism for space researches aimed to state common patterns of the radiation damage caused by heavy ions (hi), and character of hi-cell interaction. physical detectors in space experiments of the bioblock series make it possible to identify bio-objects hit by spa ...200920120909
an allelopathic substance in red pine needles (pinus densiflora).aqueous methanol extracts of red pine (pinus densiflora) needles inhibited the growth of roots and shoots of cress (lepidium sativum), lettuce (lactuca sativa), alfalfa (medicago sativa), ryegrass (lolium multiflorum), timothy (pheleum pratense), digitaria sanguinalis and echinochloa crus-galli. increasing the extract concentration increased inhibition, suggesting that the pine needles may have growth inhibitory substances and possess allelopathic potential. the aqueous methanol extract of the p ...200918755523
nonhost versus host resistance to the grapevine downy mildew, plasmopara viticola, studied at the tissue level.following inoculation of host and nonhost plants with plasmopara viticola, the grapevine downy mildew, a histological survey was undertaken to identify the stage where its development is contained in nonhosts and in resistant host plants. three herbaceous nonhost species, beta vulgaris, lactuca sativa, and capsicum annuum, and three grapevine species displaying different level of resistance (vitis vinifera [susceptible], vitis riparia [partially resistant] and muscadinia rotundifolia [totally re ...200818943253
phytochrome- and gibberellin-mediated regulation of abscisic acid metabolism during germination of photoblastic lettuce seeds.germination of lettuce (lactuca sativa) 'grand rapids' seeds is regulated by phytochrome. the action of phytochrome includes alterations in the levels of gibberellin (ga) and abscisic acid (aba). to determine the molecular mechanism of phytochrome regulation of aba metabolism, we isolated four lettuce cdnas encoding 9-cis-epoxycarotenoid dioxygenase (biosynthesis; lsnced1-lsnced4) and four cdnas for aba 8'-hydroxylase (catabolism; lsaba8ox1-lsaba8ox4). measurements of aba and its catabolites sho ...200818184730
efficient qtl detection for nonhost resistance in wild lettuce: backcross inbred lines versus f(2) population.in plants, several population types [f(2), recombinant inbred lines, backcross inbred lines (bils), etc.] are used for quantitative trait locus (qtl) analyses. however, dissection of the trait of interest and subsequent confirmation by introgression of qtls for breeding purposes has not been as successful as that predicted from theoretical calculations. more practical knowledge of different qtl mapping approaches is needed. in this recent study, we describe the detection and mapping of quantitat ...200818251002
biological and chemical evaluation of sewage water pollution in the rietvlei nature reserve wetland area, south africa.macroinvertebrate communities in rietvlei nature reserve wetland area and their relationship with water quality were studied with the aim to evaluate their use as potential indicators of pollution. sampling locations were selected to include outlets from sewage effluent, agricultural and informal residential runoff. a large increase in nutrient concentrations was observed downstream from discharged treated sewage with an associated decrease in species richness. bioassays performed included: daph ...200818280017
bioactive triterpene derivatives from latex of two euphorbia species.we have investigated the antifeedant and toxic effects of 23 semisynthetic terpenoid derivatives obtained through chemical modifications of the major components of euphorbia resinifera (alpha-euphol and alpha-euphorbol) and e. officinarum (obtusifoliol and 31-norlanostenol) latex on several insect species (spodoptera littoralis, myzus persicae and rhopalosiphum padi), their selective cytotoxicity on insect sf9 and mammalian cho cells and their phytotoxic effects on lactuca sativa. the conversion ...200818304594
novel mechanism of modulating natural antioxidants in functional foods: involvement of plant growth promoting rhizobacteria nrrl b-30488.the significance of plant growth-promoting rhizobacteria (pgpr) mediated increase in antioxidant potential in vegetables is yet unknown. the plant growth-promoting bacterium bacillus lentimorbus nrrl b-30488 (b-30488) mediated induction of dietary antioxidant in vegetables ( trigonella foenum-graecum, lactuca sativa, spinacia oleracea, and daucus carota) and fruit ( citrus sinensis) after minimal processing (fresh, boiled, and frozen) was tested by estimating the total phenol content, level of a ...200818491912
transient expression of chicken alpha interferon gene in lettuce.we investigated the possibility of producing chicken alpha interferon (chifn-alpha) in transgenic plants. the cdna encoding chifn-alpha was introduced into lettuce (lactuca sativa l.) plants by using an agro-infiltration transient expression system. the chifn-alpha gene was correctly transcribed and translated in the lettuce plants according to rt-pcr and elisa assays. recombinant protein exhibited antiviral activity in vitro by inhibition of vesicular stomatitis virus (vsv) replication on chick ...200818500773
plant response to heavy metal toxicity: comparative study between the hyperaccumulator thlaspi caerulescens (ecotype ganges) and nonaccumulator plants: lettuce, radish, and alfalfa.thlaspi caerulescens (alpine pennycress) is one of the best-known heavy metal (hm) hyperaccumulating plant species. it exhibits the ability to extract and accumulate various hm at extremely high concentrations. in this hydroponic study, the performance of t. caerulescens (ecotype ganges) to accumulate cd, zn, and cu was compared with that of three nonaccumulator plants: alfalfa (medicago sativa), radish (raphanus sativus), and lettuce (lactuca sativa). plants were exposed to the separately disso ...200818528911
uptake of sigmaddt, arsenic, cadmium, copper, and lead by lettuce and radish grown in contaminated horticultural soils.horticultural soils can contain elevated concentrations of selected trace elements and organochlorine pesticides as a result of long-term use of agrichemicals and soil amendments. a glasshouse study was undertaken to assess the uptake of weathered sigmaddt {sum of the p, p'- and o, p-isomers of ddt [1,1,1-trichloro-2,2- bis( p-chlorophenyl)ethane], dde [1,1-dichloro-2,2- bis( p-chlorophenyl)ethylene] and ddd[1,1-dichloro-2,2- bis( p-chlorophenyl)ethane]}, arsenic (as), cadmium (cd), copper (cu), ...200818624413
does subcellular distribution in plants dictate the trophic bioavailability of cadmium to porcellio dilatatus (crustacea, isopoda)?the present study examined how subcellular partitioning of cd in plants with different strategies to store and detoxify cd may affect trophic transfer of cd to the isopod porcellio dilatatus. the plant species used were lactuca sativa, a horticultural metal accumulator species; thlaspi caerulescens, a herbaceous hyperaccumulator species; and the nonaccumulator, t. arvense. taking into account that differences in subcellular distribution of cd in plants might have an important role in the bioavai ...200818624580
ssrs and indels mined from the sunflower est database: abundance, polymorphisms, and cross-taxa utility.simple sequence repeats (ssrs) are abundant and frequently highly polymorphic in transcribed sequences and widely targeted for marker development in eukaryotes. sunflower (helianthus annuus) transcript assemblies were built and mined to identify ssrs and insertions-deletions (indels) for marker development, comparative mapping, and other genomics applications in sunflower. we describe the spectrum and frequency of ssrs identified in the sunflower est database, a catalog of 16,643 est-ssrs, a col ...200818633591
germination of photoblastic lettuce seeds is regulated via the control of endogenous physiologically active gibberellin content, rather than of gibberellin responsiveness.phytochrome regulates lettuce (lactuca sativa l. cv. grand rapids) seed germination via the control of the endogenous level of bioactive gibberellin (ga). in addition to the previously identified lsga20ox1, lsga20ox2, lsga3ox1, lsga3ox2, lsga2ox1, and lsga2ox2, five cdnas were isolated from lettuce seeds: lscps, lsks, lsko1, lsko2, and lskao. using an escherichia coli expression system and functional assays, it is shown that lscps and lsks encode ent-copalyl diphosphate synthase and ent-kaurene ...200818653696
lettuce mosaic virus: from pathogen diversity to host interactors.taxonomy: lettuce mosaic virus (lmv) belongs to the genus potyvirus (type species potato virus y) in the family potyviridae. physical properties: the virion is filamentous, flexuous with a length of 750 nm and a width of 15 nm. the particles are made of a genomic rna of 10 080 nucleotides, covalently linked to a viral-encoded protein (the vpg) at the 5' end and with a 3' poly a tail, and encapsidated in a single type of capsid protein. the molecular weight of the capsid protein subunit has been ...200818705846
transgenic lettuce seedlings carrying hepatitis b virus antigen hbsag.the obtainment of transgenic edible plants carrying recombinant antigens is a desired issue in search for economic alternatives viewing vaccine production. here we report a strategy for genetic transformation of lettuce plants (lactuca sativa l.) using the surface antigen hbsag of hepatitis b virus. transgenic lettuce seedlings were obtained through the application of a regulated balance of plant growth regulators. genetic transformation process was acquired by cocultivation of cotyledons with a ...200819287831
use of polishing pond effluents to cultivate lettuce (lactuca sativa) in a hydroponic system.the sanitary quality and productivity of hydroponic lettuce (lactuca sativa l.) plants cultivated under greenhouse conditions and treated with effluent from anaerobic reactor + polishing pond followed by physical-chemical treatment was evaluated. two hydroponic cultivations were performed at summer and winter time at vitoria-es, brazil. the treatments for both cultivations were: t1) conventional nutrient solution, t2) effluent from physical-chemical treatment, t3) effluent from polishing pond, a ...200819039187
arabidopsis r2r3-myb transcription factor atmyb60 functions as a transcriptional repressor of anthocyanin biosynthesis in lettuce (lactuca sativa).the myb transcription factors play important roles in the regulation of many secondary metabolites at the transcriptional level. we evaluated the possible roles of the arabidopsis r2r3-myb transcription factors in flavonoid biosynthesis because they are induced by uv-b irradiation but their associated phenotypes are largely unexplored. we isolated their genes by race-pcr, and performed transgenic approach and metabolite analyses in lettuce (lactuca sativa). we found that one member of this prote ...200818317777
effect of combined physico-chemical processes on the phytotoxicity of olive mill wastewaters.a pool of laboratory experiments is planned with the aim of evaluating the possibility to reduce the phytotoxicity of olive mill wastewater (omw) with combined physico-chemical processes (centrifugation-ozonation, centrifugation-solar photolysis, centrifugation-solar modified photofenton, centrifugation-solar modified photofenton-ozonation). a moderate cod removal of an omw is reached by using ozonation or solar modified photofenton separately or solar modified photofenton/o(3) combined process ...200818006039
can artificial soil be used in the vegetative vigor test for u.s. pesticide registration?current testing guidelines for pesticide registration for the protection of nontarget plants calls for the use of sterilized, standardized soil consisting of primarily sandy loam, loamy sand, loamy clay, or clay loam that contains up to 3% organic matter. low organic matter soils can be difficult to manage in a greenhouse setting because when soils dry, they contract, causing impeded water infiltration, or when overwatered, poor drainage increases the chances of anaerobic conditions. the purpose ...200818563958
the natural compound benzoxazolin-2(3h)-one selectively retards cell cycle in lettuce root meristems.benzoxazolin-2(3h)-one (boa) is a natural plant product that is phytotoxic to target plant species, inhibiting germination and growth and causing oxidative damage. we investigated its effects on the root meristems of seedlings of lettuce (lactuca sativa) by means of light and transmission electron microscopy, flow cytometry, and conventional determination of mitotic index. flow cytometry analyses and mitotic index showed a retard of cell cycle in boa-treated meristems with selective activity at ...200818597799
bioactive apocarotenoids from tectona grandis.the bioactive fractions of tectona grandis have yielded seven apocarotenoids, two of which have been isolated for the first time as natural products (tectoionols a and b). the chemical structures were determined through 1d and 2d nuclear magnetic resonance experiments. the absolute configuration of tectoionol a was determined using a modified mosher methodology. some nmr assignments for the compounds 9(s)-4-oxo-7,8-dihydro-beta-ionol and 3beta-hydroxy-7,8-dihydro-beta-ionone have been corrected ...200818834604
phytotoxicity evaluation of five pharmaceutical pollutants detected in surface water on germination and growth of cultivated and spontaneous plants.the phytotoxicity of 5 pharmaceuticals detected in italian rivers, atorvastatin (7-[2-(4-fluorophenyl)-3-phenyl-4-(phenylcarbamoyl)-5-propan-2-yl-pyrrol-1-yl]-3,5-dihydroxy-heptanoic acid), gemfibrozil (5-(2,5-dimethylphenoxy)-2,2-dimethyl-pentanoic acid), tamoxifene (2-[4-(1,2-diphenylbut-1-enyl)phenoxy]-n,n-dimethyl-ethanamine), ethinyl estradiol (17-ethynyl-13-methyl-7,8,9,11, 12,13,14,15,16,17-decahydro-6h-cyclopenta[a]phenanthrene-3,17-diol) and sildenafil (methyl-9-propyl-2,4,7,8-tetrazabi ...200818205060
selecting single-copy nuclear genes for plant phylogenetics: a preliminary analysis for the senecioneae (asteraceae).compared to organelle genomes, the nuclear genome comprises a vast reservoir of genes that potentially harbor phylogenetic signal. despite the valuable data that sequencing projects of model systems offer, relatively few single-copy nuclear genes are being used in systematics. in part this is due to the challenges inherent in generating orthologous sequences, a problem that is ameliorated when the gene family in question has been characterized in related organisms. here we illustrate the utility ...200818305978
hormesis in mixtures -- can it be predicted?binary mixture studies are well established for mixtures of pollutants, pesticides, or allelochemicals and sound statistical methods are available to evaluate the results in relation to reference models. the majority of mixture studies are conducted to investigate the effect of one compound on the inhibitory action of another. however, since stimulatory responses to low concentrations of chemicals are gaining increased attention and improved statistical models are available to describe this phen ...200818640701
hybridization rates between lettuce (lactuca sativa) and its wild relative (l. serriola) under field conditions.hybridization and introgression between crops and wild relatives may have important evolutionary and ecological consequences such as gene swamping or increased invasiveness. in the present study, we investigated hybridization under field conditions between crop lettuce (lactuca sativa) and its wild relative prickly lettuce (l. serriola), two cross-compatible, predominantly autogamous and insect pollinated species. in 2003 and 2004, we estimated the rates of hybridization between l. sativa and l. ...200818549768
antifeedant and phytotoxic activity of the sesquiterpene p-benzoquinone perezone and some of its derivatives.the sesquiterpene p-benzoquinone perezone (1), isolated from perezia adnata var. alamani (asteraceae), and its non-natural derivatives isoperezone (2), dihydroperezone (3), dihydroisoperezone (4), and anilidoperezone (5) were tested as antifeedants against the herbivorous insects spodoptera littoralis, leptinotarsa decemlineata, and myzus persicae. compounds 1-5 exhibited strong antifeedant activity against l. decemlineata and m. persicae, and elicited a low response by s. littoralis. antifeedan ...200818528728
mycorrhizal and non-mycorrhizal lactuca sativa plants exhibit contrasting responses to exogenous aba during drought stress and recovery.the arbuscular mycorrhizal (am) symbiosis enhances plant tolerance to water deficit through the alteration of plant physiology and the expression of plant genes. these changes have been postulated to be caused (among others) by different contents of abscisic acid (aba) between am and non-am plants. however, there are no studies dealing with the effects of exogenous aba on the expression of stress-related genes and on the physiology of am plants. the aim of the present study was to evaluate the i ...200818469324
postharvest changes in water status and chlorophyll content of lettuce (lactuca sativa l.) and their relationship with overall visual quality.the purpose of this study was to evaluate water status, chlorophyll content (c), and overall visual quality (ovq) of fresh butter lettuce (lactuca sativa var. lores) as well as these indexes' evolution during storage and their relationships, if any. whole lettuce plants were stored at optimal postharvest conditions (0 to 2 degrees c and 97% to 99% relative humidity). measured parameters during each sampling day were relative water content (rwc), water content (wc), free water (fw), bound water ( ...200818211369
[calcium distribution in the central cell of lettuce (lactuca sativa l.) before and after pollination].potassium antimonite precipitation was used to locate calcium in the central cell of lettuce (lactuca sativa l.) before and after pollination. at 3d before anthesis, two polar nuclei of central cell separately located at two polarity of the cell, and few calcium precipitates (ppts) appeared in the polar nuclei and cytoplasm, but some ppts in its small vacuoles. at 2d before anthesis, two polar nuclei moved toward the middle of the cell and fused to form a secondary nucleus, and the ppts evidentl ...200818464591
salt in irrigation water affects the nutritional and visual properties of romaine lettuce (lactuca sativa l.).the influence of salinity stress on the growth, appearance, and nutritional compounds, especially phenolic compounds and carotenoids, of romaine lettuce (lactuca sativa l.), a low salt tolerant plant, was studied. the dry weight, height, and color of the lettuce plants were significantly changed by long-term irrigation (15 days) with higher nacl concentration (i.e., >100 mm). however, no significant differences were observed in the growth and appearance among the control, all short-term treatmen ...200818439016
development of a biomarker for metal bioavailability: the lettuce fatty acid composition.because lactuca sativa l. is a plant widely used in ecotoxicological analyses, a study was developed to determine whether the fatty acid composition of lettuce leaves could be used as an additional biomarker of soil contamination by metals such as pb, cu, zn, and cd. unlike seed germination or seedling growth, the fatty acid composition of lettuce leaves differed significantly between uncontaminated and field metal-contaminated soils. hence, this lipid biomarker might provide an early indication ...200818419182
environmental fate and effects of nicotine released during cigarette production.a variety of test methods were used to study the gradation, bioaccumulation, and toxicity of nicotine. studies included determination of the octanol-water partition coefficient, conversion to co2 in soil and activated sludge, and evaluation of the effects on microbiological and algal inhibition as well as plant germination and root elongation. the partitioning of nicotine between octanol and water indicated that nicotine will not bioaccumulate regardless of the ph of the medium. the aqueous and ...200818399728
preparation and phytotoxicity of novel kaurane diterpene amides with potential use as herbicides.novel kaurane ditepene monoamides were synthesized in good yields directly from kaurenoic ( 1) and grandiflorenic ( 2) acids and unprotected symmetrical diamines, using a modified protocol for monoacylation. amides from 1 and 2 and monoamines were also obtained and tested against seed germination and growth of radicle and shoot of lactuca sativa (lettuce), at 10 (-3), 10 (-5), and 10 (-7) m. amides from symmetrical diamines showed significant inhibitory activity at higher concentrations.200818393433
biotic interactions modify the transfer of cesium-137 in a soil-earthworm-plant-snail food web.the present study investigated the possible influence of the earthworm aporrectodea tuberculata on the transfer of cesium-137 ((137)cs) from a contaminated (130 bq/kg) deciduous forest soil to the lettuce lactuca sativa and to the snail cantareus aspersus (formerly helix aspersa) in two laboratory experiments. in the first experiment, the international organization for standardization 15952 test was used to expose snails for five weeks to contaminated soil with or without earthworms. in these co ...200818266477
metabolic fate of [14c] chlorophenols in radish (raphanus sativus), lettuce (lactuca sativa), and spinach (spinacia oleracea).chlorophenols are potentially harmful pollutants that are found in numerous natural and agricultural systems. plants are a sink for xenobiotics, which occur either intentionally or not, as they are unable to eliminate them although they generally metabolize them into less toxic compounds. the metabolic fate of [ (14)c] 4-chlorophenol (4-cp), [ (14)c] 2,4-dichlorophenol (2,4-dcp), and [ (14)c] 2,4,5-trichlorophenol (2,4,5-tcp) was investigated in lettuce, spinach, and radish to locate putative to ...200818763782
genetic variation for lettuce seed thermoinhibition is associated with temperature-sensitive expression of abscisic acid, gibberellin, and ethylene biosynthesis, metabolism, and response genes.lettuce (lactuca sativa 'salinas') seeds fail to germinate when imbibed at temperatures above 25 degrees c to 30 degrees c (termed thermoinhibition). however, seeds of an accession of lactuca serriola (uc96us23) do not exhibit thermoinhibition up to 37 degrees c in the light. comparative genetics, physiology, and gene expression were analyzed in these genotypes to determine the mechanisms governing the regulation of seed germination by temperature. germination of the two genotypes was differenti ...200818753282
role of syrphid larvae and other predators in suppressing aphid infestations in organic lettuce on california's central coast.organic lettuce, lactuca sativa l., growers on the central coast of california rely on conservation biological control to manage nasonovia ribisnigri mosley (hemiptera: aphididae) and other aphid pests of lettuce. in 2006, we carried out five replicated field trials to determine the importance of syrphid larvae in the suppression of n. ribisnigri and other aphids infesting organic romaine lettuce. we used entrust, a spinosad-based insecticide approved for use on organic farms, to suppress syrphi ...200818950033
phytotoxic effects of leukamenin e (an ent-kaurene diterpenoid) on root growth and root hair development in lactuca sativa l. seedlings.leukamenin e, an ent-kaurene diterpenoid isolated from isodon racemosa (hemsl) hara, showed phytotoxic effects on root growth and root hair development of lettuce seedlings (lactuca sativa l.). lower concentrations (10 microm) of leukamenin e did not affect root growth, but at concentrations higher than 50 microm, the rate was inhibited. the influence of leukamenin e on root growth rate was closely correlated with alterations in the mitotic index. a low incidence of aberrant mitosis image was ob ...200818937011
chemical characterization of new oxylipins from cestrum parqui, and their effects on seed germination and early seedling growth.isolation, chemical characterization, and phytotoxicity of five new oxylipins, together with seven already known related compounds, from cestrum parqui l' hérl. is reported. all the structures were elucidated on the basis of their spectral data, especially 1d-(1h- and 13c-nmr, dept) and 2d-nmr (cosy, tocsy, hsqc, hmbc, and noesy). the configurations of the stereogenic c-atoms were determined by the mosher's method. the compounds have been assayed for their phytotoxicity on lactuca sativa at conc ...200818816534
quantitative trait loci associated with lettuce seed germination under different temperature and light environments.temperature and light are primary environmental cues affecting seed germination. to elucidate the genetic architecture underlying lettuce (lactuca sativa l.) seed germination under different environmental conditions, an f8 recombinant inbred line population consisting of 131 families was phenotyped for final germination and germination rate. seeds were imbibed in water at 20 degrees c under continuous red light (20-rc), 20 degrees c continuous dark (20-dc), 31.5 degrees c continuous red light (3 ...200818956026
oil palm waste and synthetic zeolite: an alternative soil-less growth substrate for lettuce production as a waste management practice.a study was conducted to assess the characteristics and the prospective utilization of oil palm waste (op) and synthetic zeolite (sz) developed by coal fly ash, as an alternative substrate to peat and commercial perlite for lettuce (lactuca sativa l.) production. the sz, op, sphagnum peat (pe), perlite (pl) and two different sz-op mixtures (v/v) at the ratio of 1 : 3 and 1 : 10 were utilized as the substrates under this study. the substrates formulated by mixing sz with op at the ratio of 1 : 3 ...200819039073
phenyl cinnamate derivatives from oxalis pes-caprae.during the screening of mediterranean invasive plants, oxalis pes-caprae was identified as promising species. the fresh leaves and twigs of the plant were crumbled and extracted with acoet. the solution was concentrated, and separated into acidic and neutral fractions. the crude neutral residue was fractionated by chromatographic procedures, followed by structure elucidation on the basis of 1h- and 13c-nmr, and ms data analysis, and six new phenyl cinnamate derivatives were identified. the phyto ...200819035569
separating the effects of hypobaria and hypoxia on lettuce: growth and gas exchange.the objectives of this research were to determine the influence of hypobaria (reduced atmospheric pressure) and reduced partial pressure of oxygen (po2) [hypoxia] on carbon dioxide (co2) assimilation (c(a)), dark-period respiration (dpr) and growth of lettuce (lactuca sativa l. cv. buttercrunch). lettuce plants were grown under variable total gas pressures [25 and 101 kpa (ambient)] at 6, 12 or 21 kpa po2)(approximately the partial pressure in air at normal pressure). growth of lettuce was compa ...200718251894
chromosomal study of lettuce and its allied species (lactuca spp., asteraceae) by means of karyotype analysis and fluorescence in situ hybridization.in this study, in addition to the karyotype analysis, the chromosomal distributions of 5 s and 18 s rdnas, and the arabidopsis-type (t3ag3) telomeric sequences were detected by means of fluorescence in situ hybridization (fish) to promote the information of chromosomal organization and evolution in the cultivated lettuce and its wild relatives, l. sativa, l. serriola, l. saligna and l. virosa. the karyotype analysis revealed the dissimilarity between l. virosa and the remaining species. in all f ...200718215246
effect of methyl jasmonate on phenolic compounds and carotenoids of romaine lettuce (lactuca sativa l.).the effect of exogenous methyl jasmonate (meja) on antioxidative compounds of romaine lettuce ( lactuca sativa l.) was investigated. lettuces were treated with various meja solutions (0, 0.05, 0.1, 0.25, and 0.5 mm) before harvest. total phenolic compounds content and antioxidant capacity of romaine lettuce significantly increased after meja treatments (0.1, 0.25, and 0.5 mm). the total content of phenolic compounds of the romaine lettuce treated with 0.5 mm meja (31.6 microg of gallic acid equi ...200717990849
[studies on the calcium distribution in developing synergids of lettuce (lactuca sativa l.)].potassium antimonite was used to locate calcium in the synergids of lettuce (lactuca sativa l) during their development. the two synergids on 3d before anthesis formed evident polarity with most cytoplasm located in the micropylar end and nucleus in the middle and a big vacuole in the chalazal end. at this time, calcium precipitates were a few in both cells. calcium precipitates in the two synergids began to increase on 2d before anthesis. synergid wall in the micropylar end thickened on 1d befo ...200717966463
cinnamic ester derivatives from oxalis pes-caprae (bermuda buttercup).seven new cinnamic ester derivatives ( 1- 7) were isolated from a methanol extract of the fresh leaves and twigs of oxalis pes-caprae (bermuda buttercup). the structures of these new compounds were determined by spectroscopic data interpretation. the effects of compounds 1- 7 on the germination and growth of lactuca sativa (lettuce) were studied.200717922549
relationship between lead uptake by lettuce and water-soluble low-molecular-weight organic acids in rhizosphere as influenced by transpiration.the relationship between pb uptake by leaf lettuce ( lactuca sativa l.) and water-soluble low-molecular-weight organic acids (lmwoas) in rhizosphere, as influenced by transpiration (high and low), has been studied. studies were carried out by culturing lettuce plants grown for 2 weeks in pots filled with quartz sand mixed with anion-exchange resin and then for 30 days in a greenhouse. the potted lettuce plants were subjected to stress by the addition of pb(no 3) 2 solutions (100, 200, and 300 mg ...200717894455
an assessment of the role of ethylene in mediating lettuce (lactuca sativa) root growth at high temperatures.growth of temperate lettuce (lactuca sativa) plants aeroponically in tropical greenhouses under ambient root-zone temperatures (a-rzts) exposes roots to temperatures of up to 40 degrees c during the middle of the day, and severely limits root and shoot growth. the role of ethylene in inhibiting growth was investigated with just-germinated (24-h-old) seedlings in vitro, and 10-d-old plants grown aeroponically. compared with seedlings maintained at 20 degrees c, root elongation in vitro was inhibi ...200717728295
withanolides from jaborosa kurtzii.two new withanolides were isolated and characterized from the aerial parts of jaborosa kurtzii, namely, jaborosalactone 43 (1), with a spiranoid delta-lactone at c-22, and jaborosalactone 44 (2), a 12-oxowithanolide, which may function as a biosynthetic precursor to 1. these new compounds were fully characterized by a combination of spectroscopic methods. compound 1 showed selective phytotoxicity toward a dicotyledon species, lactuca sativa (lettuce).200717711343
absorption of selenium by lactuca sativa as affected by carboxymethylcellulose.several organic compounds of high molecular weight present in soil interact with selenium and may act as active binding agents affecting its availability in soil, and, consequently, selenium uptake by plants. this study is aimed at investigating the effects of polysaccharides on selenium speciation in soil and on selenium absorption by lactuca sativa l. plants. three-week-old seedlings were transplanted into pots filled with soil, and sodium selenite at rates of 1.5 and 5mgsekg(-1) of soil, or s ...200717107704
toxicity assessment of a complex industrial wastewater using aquatic and terrestrial bioassays daphnia pulex and lactuca sativa.aquatic and terrestrial bioassays were used to assess toxicity at several stages in an industrial wastewater treatment plant that processes 400 l/s from a complex influent formed by wastewater from 135 industries. daphnia pulex and lactuca sativa were used to assess and compare toxicity between the influent wastewater and effluent wastewater from an activated sludge process, and compare their relationship with physicochemical parameters of biological oxygen demand (bod); chemical oxygen demand ( ...200717680481
effects of genotype and transpiration rate on the uptake and accumulation of perchlorate (clo4-) in lettuce.although evidence of perchlorate accumulation in plants exists, there is a scarcity of information concerning the key factors and mechanisms involved. to ascertain whether genotypic variation in perchlorate accumulation occurs within lettuce, hydroponic plant uptake experiments were conducted with five types of lettuce (lactuca sativa l.), which were grown to market size atthree perchlorate (clo4-) concentrations (1, 5, or 10 microg/l). perchlorate accumulated in the leafy tissues to varying amo ...200717539550
ecotoxicological tests assessment of soils polluted by chromium (vi) or pentachlorophenol.carbon mineralisation and plant germination and growth (lactuca sativa seeds) tests have been performed in two soils of different properties, experimentally spiked with pentachlorophenol (pcp) or cr (vi), in concentrations between 0.001 and 1000 mg kg(-1). the evaluation has been done considering the following parameters of carbon transformation test: soil cumulative basal respiration after 14 days incubation, substrate induced respiration after 12 h of glucose addition, and, in the plant germin ...200717379274
molecular characterisation of lac s 1, the major allergen from lettuce (lactuca sativa).ige sensitisation to non-specific lipid transfer proteins (nsltp), e.g., pru p 3 the major allergen from peach and most important allergenic ltp, is strongly associated with severe symptoms in food allergic patients. lac s 1, a member of the nsltp protein family, was recently identified as major allergen in lettuce (lactuca sativa), but has not yet been investigated on the molecular basis.200717349693
qtls for shelf life in lettuce co-locate with those for leaf biophysical properties but not with those for leaf developmental traits.developmental and biophysical leaf characteristics that influence post-harvest shelf life in lettuce, an important leafy crop, have been examined. the traits were studied using 60 informative f9 recombinant inbed lines (rils) derived from a cross between cultivated lettuce (lactuca sativa cv. salinas) and wild lettuce (l. serriola acc. uc96us23). quantitative trait loci (qtls) for shelf life co-located most closely with those for leaf biophysical properties such as plasticity, elasticity, and br ...200717347132
determination of phytotoxicity of soluble elements in soils, based on a bioassay with lettuce (lactuca sativa l.).in this work the different concentrations of soluble elements in soils from natural (peridotitic soils) and anthropogenic (soils affected by a pyrite-mine spill) origin, are used to determine the phytotoxicity in lettuce (lactuca sativa l.). the solutions are obtained from soil:water extracts (1:1), having neutral ph and high concentrations of as, pb, zn, mn, co and ni, with values exceeding the toxic level for soil solution [bohn hl, mcneal bl, o'connor ga. soil chemistry, wiley interscience. w ...200717316769
preparation of 2h-furo[2,3-c]pyran-2-one derivatives and evaluation of their germination-promoting activity.the butenolide, 3-methyl-2h-furo[2,3-c]pyran-2-one (1), has recently been identified as the germination stimulant present in smoke that promotes the germination of seeds from a wide range of plant species. in this paper, we describe the preparation of a number of analogues of 1 and compare their efficacy in promoting seed germination of three highly smoke-responsive plant species, lactuca sativa l. cv. grand rapids (asteraceae), emmenanthe penduliflora benth. (hydrophyllaceae), and solanum orbic ...200717316021
phytotoxicity of secondary metabolites from aptenia cordifolia.from the fresh leaves or twigs of aptenia cordifolia, a total of 29 compounds were isolated, including the new tetranoroxyneolignan 18, the new dilignan 19, and the beta-ionone derivative 27, previously only known as a synthetic compound, together with 26 known compounds. the structures of the new products were determined by (1)h-, (13)c-, and 2d-nmr, as well as hr-ms analyses. the phytotoxic effects of the isolates on the germination and growth of the dicotyledon lactuca sativa l. (lettuce) wer ...200717311224
polyphenol content and antioxidative activity in some species of freshly consumed salads.ten genotypes belonging to lactuca sativa, cicorium intybus, plantago coronopus, eruca sativa, and diplotaxis tenuifolia and used in fresh mixed salads were investigated for their polyphenol contents. flavonoids and hydroxycinnamic acids were characterized by high-performance liquid chromatography (hplc)/diode array detection/mass spectrometry. quercetin, kaempferol, luteolin, apigenin, and crysoeriol derivatives were identified; hydroxycinnamic acids were all caffeoyl derivatives. the total pol ...200717279769
genetic distance sampling: a novel sampling method for obtaining core collections using genetic distances with an application to cultivated lettuce.this paper introduces a novel sampling method for obtaining core collections, entitled genetic distance sampling. the method incorporates information about distances between individual accessions into a random sampling procedure. a basic feature of the method is that automatically larger samples are obtained if accessions are further apart and smaller samples if accessions are closer together. genetic distance sampling can be used in conjunction with predefined stratifications of the accessions. ...200717180377
a survey of syrphid predators of nasonovia ribisnigri in organic lettuce on the central coast of california.organic lettuce, lactuca sativa l., producers on california's central coast rely on endemic syrphid flies (diptera: syrphidae) to suppress populations of nasonovia ribisnigri mosley (homoptera: aphididae) and other aphids affecting lettuce. growers are using various forms of habitat manipulation to enhance biological control. we surveyed syrphids collected from organic romaine in and around the salinas valley from march through september 2005 to gain a better understanding of the species respons ...200717370807
mechanism of selective phytotoxicity of l-3,4-dihydroxyphenylalanine (l-dopa) in barnyardgrass and lettuce.l-3,4-dihydroxyphenylalanine (l-dopa) is one of the few allelochemicals in which the phytotoxic action mechanism has been studied. excess exogenous l-dopa suppresses root elongation in some plant species, and the inhibitory action is species-selective. the main factor of phytotoxicity of l-dopa is considered to be oxidative damage by reactive oxygen species (ros) and/or free radical species (frs). this study was performed to elucidate the mechanism of species-selective phytotoxicity. the involve ...200717899281
simultaneous modelling of the thermal degradation kinetics of pectin methylesterase in lettuce (lactuca sativa l.) and carrot (daucus carota l.) extracts: analysis of seasonal variation and tissue type.the thermal degradation kinetics of pectin methylesterase (pme) from carrot and lettuce were studied. fresh extracts were exposed to temperatures from 55 to 70 degrees c until the enzyme was inactivated. a model based on the presence of two forms of the enzyme, one active and one non-active, is proposed. the natural variability of the pme activity was taken into the model in the form of normally distributed random effects. the common model parameters obtained (cleavage constant (0.0395+/-0.0062 ...200717928712
comparative cross-species alternative splicing in plants.alternative splicing (as) can add significantly to genome complexity. plants are thought to exhibit less as than animals. an algorithm, based on expressed sequence tag (est) pairs gapped alignment, was developed that takes advantage of the relatively small intron and exon size in plants and directly compares pairs of ests to search for as. est pairs gapped alignment was first evaluated in arabidopsis (arabidopsis thaliana), rice (oryza sativa), and tomato (solanum lycopersicum) for which annotat ...200717496110
phytotoxic eremophilanes from ligularia macrophylla.systematic bioassay-guided fractionation of the methylene chloride extract of the roots from ligularia macrophylla was performed to identify both phytotoxic and antifungal compounds. four phytotoxic eremophilanes (furanoeremophilan-14beta,6alpha-olide, 6beta-angeloyloxy-10beta-hydroxyfuranoeremophilane, eremophil-7(11)-ene-12,8alpha;14beta,6alpha-diolide, and 3alpha-angeloyloxybakkenolide a) and two antifungal fatty acids (linoleic acid and alpha-linolenic acid) were isolated. the x-ray crystal ...200718044832
allelopathy on bark of downed logs of chamaecyparis obtusa sieb. and zucc. var. formosana (hayata) rehder.chamaecyparis obtusa sieb. and zucc. var. formosana (hayata) rehder is the dominant species in the temperate forest of yuanyang lake nature reserve (yyl), taiwan. although downed logs of c. obstusa var. formosana occupy only a small percentage of the forest floor area in yyl, they are important regeneration substrates. seedlings of this species often grow without competition on the new downed logs, and a few broadleaf trees grow with them. we hypothesized that the bark of the newly fallen logs p ...200717476467
behavioral responses of schistocerca americana (orthoptera: acrididae) to azadirex (neem)-treated host plants.azadirex (azadirachtin and other biologically active extracts from neem trees) has been shown to have considerable potential to be used in integrated pest management systems based on its growth regulator/insecticide properties. less well known are the antifeedant properties. the feeding-deterrent properties of a commercial azadirex formulation (azatrol ec) were evaluated using both no-choice and choice tests, the american grasshopper, schistocerca americana (drury), and four host plants [savoy c ...200717370818
response of five lettuce cultivars to root-knot nematode, meloidogyne incognita.the root-knot nematode, meloidogyne incognito (kofoid et white) chitwood is an important pathogen of vegetables. five commercial cultivars of lettuce (lactuca sativa l.) were evaluated under greenhouse conditions for resistance to meloidogyne incognita, benguet population. plants were inoculated with 1000 eggs collected from 'apollo' tomato (lycopersicon esculentum) roots. the degree of galling and number of egg masses were assessed 4 and 8 weeks after inoculation. host plant response was classi ...200718399501
a comparative analysis of the lactuca and helianthus (asteraceae) plastid genomes: identification of divergent regions and categorization of shared repeats.we have sequenced two complete chloroplast genomes in the asteraceae, helianthus annuus (sunflower), and lactuca sativa (lettuce), which belong to the distantly related subfamilies, asteroideae and cichorioideae, respectively. the helianthus chloroplast genome is 151 104 bp and the lactuca genome is 152 772 bp long, which is within the usual size range for chloroplast genomes in flowering plants. when compared to tobacco, both genomes have two inversions: a large 22.8-kb inversion and a smaller ...200721636403
identification of race 1 of fusarium oxysporum f. sp. lactucae on lettuce by inter-retrotransposon sequence-characterized amplified region technique.abstract fusarium wilt of lettuce, caused worldwide by fusarium oxysporum f. sp. lactucae, is an emerging seed-transmitted disease on lactuca sativa. in order to develop a molecular diagnostic tool for identifying race 1 (vcg0300) of the pathogen on vegetable samples, an effective technique is presented. inter-retrotransposon amplified polymorphism polymerase chain reaction (pcr), a technique based on the amplification of genomic regions between long terminal repeats, was applied. it was shown t ...200718943639
ecotoxicity monitoring of hydrocarbon-contaminated soil during bioremediation: a case study.the ecotoxicity of hydrocarbon-contaminated soil originating from a brownfield site was evaluated during a 17-month biodegradation pilot test. the initial concentration of total petroleum hydrocarbons (tphs) in the soil was 6380 microg/g dry weight. an amount of 200 kg soil was inoculated with 1.5 l of the bacterial preparation gem-100 containing pseudomonas sp. and acinetobacter sp. strains (5.3 x 10(10) cfu.ml(-1)) adapted to diesel fuel. the concentration of tphs in the soil decreased by 65.5 ...200717106791
heterologous expression of the mutated melon ethylene receptor gene cm-ers1/h70a produces stable sterility in transgenic lettuce (lactuca sativa).the mutated melon ethylene receptor gene cm-ers1/h70a was introduced into tobacco and induced stable sterility in transgenic lines. this gene contains a missense mutation that converts the his(70) residue to ala in the melon ethylene receptor gene cm-ers1. to test the applicability of this inducible sterility system to other plants, lettuce (lactuca sativa) was transformed with the gene using agrobacterium, and putative transformants containing cm-ers1/h70a were obtained. thirteen randomly selec ...200717207555
solid-state cultures of fusarium oxysporum transform aromatic components of olive-mill dry residue and reduce its phytotoxicity.the present study mainly investigated the ability of solid-state cultures of the non-pathogenic fusarium oxysporum strain bafc 738 to transform aromatic components to reduce the phytotoxicity in olive-mill dry residue (dor), the waste from the two-phase manufacturing process. lignin, hemicellulose, fats and water-soluble extractives contents of dor colonized by the fungus for 20 weeks were reduced by 16%, 25%, 71% and 13%, respectively, while the cellulose content increased by 25%. in addition, ...200717207620
extreme size and sequence variation in the its rdna of bremia lactucae.bremia lactucae regel (chromista, peronosporaceae) is an economically destructive pathogen, which causes downy mildew disease on lettuce (lactuca sativa l.) worldwide. the ribosomal internal transcribed spacer (its) of bremia lactucae isolates was analyzed for the first time. the its region of lettuce downy mildew was observed to have a size of 2458 bp; thereby, having one of the longest its sizes recorded to date. the majority of the extremely large sized its2 length of 2086 was attributed to t ...200717286165
successful gene tagging in lettuce using the tnt1 retrotransposon from tobacco.the tobacco (nicotiana tabacum) element tnt1 is one of the few identified active retrotransposons in plants. these elements possess unique properties that make them ideal genetic tools for gene tagging. here, we demonstrate the feasibility of gene tagging using the retrotransposon tnt1 in lettuce (lactuca sativa), which is the largest genome tested for retrotransposon mutagenesis so far. of 10 different transgenic bushes carrying a complete tnt1 containing t-dna, eight contained multiple transpo ...200717351058
ecotoxicity of a polycyclic aromatic hydrocarbon (pah)-contaminated soil.soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (pahs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. the total concentration of the 16 pahs listed as priority pollutants by the us environmental protection agency (us-epa) was 2634+/-241 mg/kgdw in soil samples. the toxicity of water-extractable pollutants from the contaminated soil samples was evaluated using acute (vibrio fischeri; microtox test, daphnia ma ...200717382389
toxicity evaluation of the process effluent streams of a petrochemical industry.the physico-chemical characteristics and the acute toxicity of several wastewater streams, generated in the industrial production of synthetic rubber, were determined. the acute toxicity was evaluated in bioassays using different organisms: danio rerio (fish), lactuca sativa (lettuce) and brachionus calyciflorus (rotifer). the removal of toxicity attained in the industrial wastewater treatment plant was also determined upstream and downstream of the activated sludge process. the results obtained ...200717396408
physiological and molecular responses of lactuca sativa to colonization by salmonella enterica serovar dublin.this paper describes the physiological and molecular interactions between the human-pathogenic organism salmonella enterica serovar dublin and the commercially available mini roman lettuce cv. tamburo. the association of s. enterica serovar dublin with lettuce plants was first determined, which indicated the presence of significant populations outside and inside the plants. the latter was evidenced from significant residual concentrations after highly efficient surface disinfection (99.81%) and ...200717513585
silencing of the major family of nbs-lrr-encoding genes in lettuce results in the loss of multiple resistance specificities.the rgc2 gene cluster in lettuce (lactuca sativa) is one of the largest known families of genes encoding nucleotide binding site-leucine-rich repeat (nbs-lrr) proteins. one of its members, rgc2b, encodes dm3 which determines resistance to downy mildew caused by the oomycete bremia lactucae carrying the cognate avirulence gene, avr3. we developed an efficient strategy for analysis of this large family of low expressed genes using post-transcriptional gene silencing (ptgs). we transformed lettuce ...200717587302
sulfamethazine uptake by plants from manure-amended soil.animal manure is applied to agricultural land as a means to provide crop nutrients. however, animal manure often contains antibiotics as a result of extensive therapeutic and subtherapeutic use in livestock production. the objective of this study was to evaluate plant uptake of a sulfonamide-class antibiotic, sulfamethazine, in corn (zea mays l.), lettuce (lactuca sativa l.), and potato (solanum tuberosum l.) grown in a manure-amended soil. the treatments were 0, 50, and 100 microg sulfamethazin ...200717596632
relay cropping cauliflower with lettuce as a means to manage first-generation cabbage maggot (diptera: anthomyiidae) and minimize cauliflower yield loss.first-generation cabbage maggot, delia radicum (l.) (diptera: anthomyiidae), can cause extensive damage to newly transplanted brassica crops. this study investigated the use of relay cropping, a form of intercropping that involves overlapping two crops in the same field for a short period, as a means to 1) reduce first-generation d. radicum egg numbers by disrupting female host finding and 2) minimize yield loss by reducing the time that crops overlap. because of the high incidence of two other ...200717598546
localisation and metabolism of reactive oxygen species during bremia lactucae pathogenesis in lactuca sativa and wild lactuca spp.a plant's physiology is modified simultaneously with oomycete pathogen penetration, starting with release and accumulation of reactive oxygen species (ros). localisation of superoxide, hydrogen peroxide, peroxidase and variation in their activity, and the isoenzyme profile of antioxidant enzymes peroxidase (1.11.1.7), catalase (ec 1.11.1.6), superoxide dismutase (ec 1.15.1.1) were studied in six genotypes of four lactuca spp. (l. sativa, l. serriola, l. saligna and l. virosa) challenged with bre ...200717629488
assessment of contamination potential of lettuce by salmonella enterica serovar newport added to the plant growing medium.the capacity of salmonella enterica serovar newport to contaminate romaine lettuce (lactuca sativa l. cv. nogal) via the root system was evaluated in 17-, 20-, and 33-day-old plants. apparent internalization of salmonella via the root to the above-ground parts was identified in 33- but not 17- or 20-day-old plants and was stimulated by root decapitation. leaves of lettuce plants with intact and damaged roots harbored salmonella at 500 +/- 120 and 5,130 +/- 440 cfu/g of leaf, respectively, at 2 d ...200717685348
overexpression of arabidopsis homogentisate phytyltransferase or tocopherol cyclase elevates vitamin e content by increasing gamma-tocopherol level in lettuce (lactuca sativa l.).tocopherols, essential components of the human diet, are synthesized exclusively by photosynthetic organisms. to increase tocopherol content by increasing total flux to the tocopherol biosynthetic pathway, genes encoding arabidopsis homogentisate phytyltransferase (hpt/v-te2) and tocopherol cyclase (tc/vte1) were constitutively overexpressed in lettuce (lactuca sativa l.). total tocopherol content of the transgenic plants overexpressing either of the genes was increased by more than 2-fold mainl ...200717978586
strong increase of foliar inulin occurs in transgenic lettuce plants (lactuca sativa l.) overexpressing the asparagine synthetase a gene from escherichia coli.transgenic lettuce (lactuca sativa l. cv. 'cortina') lines expressing the asparagine synthetase a gene from escherichia coli were produced to alter the plant nitrogen status and eventually enhance growth. the relative molecular abundance of water-soluble metabolites was measured by 1h nmr in transgenic and conventional plants at early developmental stages and grown under the same conditions. nmr metabolic profiles assessed that a transgenic line and the wild-type counterpart shared the same comp ...200718044837
shelf-life extension of fresh-cut iceberg lettuce (lactuca sativa l) by different antimicrobial films.this study was conducted to investigate the antibacterial activity and shelf-life extension effect of iceberg lettuce packed in bn/pe film. the bn/pe film has a strong microbial suppression effect on pathogenic bacteria such as escherichia coli, salmonella enteritidis, and s. typhimurium. the number of psychrophiles and mesophiles during 5 days of cold storage of fresh-cut iceberg lettuce at 10 degrees c packaged in bn/pe film was strictly suppressed in comparison with other tested films (opp, p ...200718051596
phytotoxicity and accumulation of anthracene applied to the foliage and sandy substrate in lettuce and radish plants.the effects of anthracene (ant) on the growth of two species of vegetable plants (lactuca sativa l. and raphanus sativus l.), which play an important role in the human diet, were studied. ant was applied to the leaves of these plants by foliar deposition, in aerosol form, and to the sandy substrate in which the plants were grown in a greenhouse. it was found that ant affected plant biomass, especially root biomass, in the case of both foliar and soil application. under conditions of induced chem ...200716368141
synthesis and assembly of escherichia coli heat-labile enterotoxin b subunit in transgenic lettuce (lactuca sativa).escherichia coli heat-labile enterotoxin b subunit (ltb) strongly induces immune responses and can be used as an adjuvant for co-administered antigens. synthetic ltb (sltb) based on optimal codon usage by plants was introduced into lettuce cells (lactuca sativa) by agrobacterium tumefaciens-mediated transformation methods. the sltb gene was detected in the genomic dna of transgenic lettuce leaf cells by pcr dna amplification. synthesis and assembly of the sltb protein into oligomeric structures ...200716919472
quantification of contamination of lettuce by gfp-expressing escherichia coli o157:h7 and salmonella enterica serovar typhimurium.the primary objective of this study was to determine the possibility of internalization of gfp-expressing escherichia coli o157:h7 and salmonella enterica serovar typhimurium (s. typhimurium) strains mae 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (lactuca sativa cv. tamburo) grown in an inoculated hydroponic and soil system. the second aim was to quantify the level of contamination with the use of a proper surface sterilization method. silver nitrate wa ...200716943102
lettuce (lactuca sativa l.).lettuce is a globally important leafy vegetable with the united states being the largest world producers. the crop is susceptible to a number of viruses that are aphid transmitted and also highly vulnerable to post harvest diseases. although wild species of lettuce are an important source of disease resistance genes, their introgression into commercial lettuce has been limited owing to sexual incompatibilities. hence, the development of a gene transfer system for lettuce would be extremely valua ...200616988367
effectiveness of two-sided uv-c treatments in inhibiting natural microflora and extending the shelf-life of minimally processed 'red oak leaf' lettuce.the use of uv-c radiation treatments to inhibit the microbial growth and extend the shelf-life of minimally processed 'red oak leaf' lettuce was investigated. initially, uv-c resistance of 20 bacterial strains from different genera often associated with fresh produce (enterobacter, erwinia, escherichia, leuconostoc, pantoea, pseudomonas, rahnela, salmonella, serratia and yersinia) were tested in vitro. most of the bacterial strains were inhibited with the minimum dose (30 j m(-2)). erwinia carot ...200616943010
selecting a battery of bioassays for ecotoxicological characterization of wastes.this study was conducted in france within the context of waste classification (hazardous waste council directive 91/689/eec), and focused on "ecotoxic" property (h14). in 1998, an experimental test strategy was developed to assess ecotoxicological properties of wastes using a battery of six standardized bioassays. this combined direct and indirect approaches integrating two solid-phase tests: emergence and growth inhibition of lactuca sativa (14 days), mortality of eisenia fetida (14 days) and f ...200616545863
evaluating the contribution of soil properties to modifying lead phytoavailability and phytotoxicity.soil properties affect pb bioavailability to human and ecological receptors and should be considered during ecological risk assessment of contaminated soil. we used path analysis (pa) to determine the relative contribution of soil properties (ph, organic c [oc], amorphous fe and al oxides [feal], and cation-exchange capacity [cec]) in modifying pb bioavailability. the response of biological endpoints (bioaccumulation and dry matter growth [dmg]) of lettuce (lactuca sativa) grown on 21 pb-spiked ...200616566156
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