| magnesium absorption in human subjects from leafy vegetables, intrinsically labeled with stable 26mg. | collards, turnip greens, leaf lettuce, and spinach, grown in nutrient solution so that their mg content was 80 to 90% 26mg, were tested in ambulant male volunteers stabilized on a constant metabolic diet. the freeze-dried vegetables were incorporated in bran muffins in which the vegetables replaced part of the bran. bran muffins without vegetables were consumed for breakfast each day. they were also used as a standard test meal to which the vegetable muffins were compared. all subjects participa ... | 1984 | 6711467 |
| an outbreak of escherichia coli o157:h7 infections associated with leaf lettuce consumption. | in july 1995, 40 montana residents were identified with laboratory-confirmed escherichia coli o157:h7 infection; 52 residents had bloody diarrhea without laboratory confirmation. the median age of those with laboratory-confirmed cases was 42 years (range, 4- 86); 58% were female. thirteen patients were hospitalized, and 1 developed hemolytic-uremic syndrome. a case-control study showed that 19 (70%) of 27 patients but only 8 (17%) of 46 controls reported eating purchased (not home-grown) leaf le ... | 1998 | 9607837 |
| pathogenesis, treatment, and therapeutic trials in hemolytic uremic syndrome. | diarrhea-associated hemolytic uremic syndrome is one of the most common causes of acute renal failure in childhood. nearly all cases are the result of an antecedent infection by shiga toxin--producing strains of escherichia coli, especially the o157:h7 serotype. most cases occur after ingestion of contaminated meat; however, new food sources such as leaf lettuce, alfalfa sprouts, and goat's milk have been identified, and diarrhea-associated hemolytic uremic syndrome can occur after exposure to c ... | 1999 | 10202627 |
| children's descriptions of fractal shapes. | elementary-school students (n = 359), who had not been introduced to fractal geometry, examined and described the shape of three fractal sets, i.e., batter-fried chicken, popcorn, and curly leaf lettuce. the data were generated during individual, untimed, semistructured interviews. in general, the children used terminology of classical geometry to describe the shape of the popcorn, and they used adjectives, phrases, created words, and classical geometric terminology to describe the shape of the ... | 1999 | 10483660 |
| a century of plant virus management in the salinas valley of california, 'east of eden'. | the mild climate of the salinas valley, ca lends itself well to a diverse agricultural industry. however, the diversity of weeds, crops and insect and fungal vectors also provide favorable conditions for plant virus disease development. this paper considers the incidence and management of several plant viruses that have caused serious epidemics and been significant in the agricultural development of the salinas valley during the 20th century. beet curly top virus (bctv) almost destroyed the newl ... | 2000 | 11137170 |
| survival of helicobacter pylori in ready-to-eat foods at 4 degrees c. | the survival of helicobacter pylori (nctc 11638) in various semiprocessed and fresh, ready-to-eat foods, and one raw chicken was studied at 4 degrees c and under aerobic conditions by experimentally inoculating these with 10(4) cfu. cells were concentrated by two centrifugation cycles followed by plating onto selective blood agar medium made from wilkins-chalgren agar supplemented with 5% whole horse blood, and 30 mg/l colistin methanesulfonate, 100 mg/l cycloheximide, 30 mg/l nalidixic acid, 30 ... | 2001 | 11246912 |
| expression of red-shifted green fluorescent protein by escherichia coli o157:h7 as a marker for the detection of cells on fresh produce. | escherichia coli o157:h7 was transformed with a plasmid vector red-shifted green fluorescence protein (pegfp) to express red-shifted green fluorescence protein (egfp) from aequorea victoria. the egfp expression among total cells and nonviable cells was determined at the cellular level by microscopic observation of immunostained and membrane-impermeable, dye-stained cultures, respectively. e. coli o157:h7 retained pegfp during frozen storage at -80 degrees c. the percentage of egfp expression was ... | 2001 | 11252470 |
| evaluation of a polymerase chain reaction-based system for detection of salmonella enteritidis, escherichia coli o157:h7, listeria spp., and listeria monocytogenes on fresh fruits and vegetables. | a polymerase chain reaction (pcr)-based detection system, bax, was evaluated for its sensitivity in detecting salmonella enteritidis, escherichia coli o157:h7, listeria sp., and listeria monocytogenes on fresh produce. fifteen different types of produce (alfalfa sprouts, green peppers, parsley, white cabbage, radishes, onions, carrots, mushrooms, leaf lettuce, tomatoes, strawberries, cantaloupe, mango, apples, and oranges) were inoculated, in separate studies, with salmonella enteritidis, e. col ... | 2001 | 11403127 |
| modification of yield and chlorophyll content in leaf lettuce by hps radiation and nitrogen treatments. | this study evaluated the potential of high photosynthetic photon flux (ppf) from high-pressure sodium (hps) lamps, alone or in combination with metal halide (mh) plus quartz iodide (qi) incandescent lamps, to support lettuce growth, with or without n supplementation. varying exposures to radiation from combined hps, mh, and qi lamps influenced dry weight gain and photosynthetic pigment content of hydroponically grown black-seeded simpson' lettuce (lactuca sativa l.) seedlings. cumulative leaf ... | 1991 | 11537726 |
| environmental modification of yield and nutrient composition of 'waldmann's green' leaf lettuce. | leaf number, dry weight, and nutrient composition of lactuca sativa l. cv. waldmann's green leaves were compared following 9 days of treatment in a controlled environment room under various combinations of photosynthetic photon flux (ppf:350 vs 800 micromoles m-2 s-1), atmospheric co2 level (ambient vs 1500 micromoles mol-1), and single-strength (1x:15 mm) vs double-strength (2x:30 mm) nitrogen (n) as no3- alone or as nh4(+) + no3- (1:5 molar ratio). co2 enrichment greatly enhanced leaf number u ... | 1997 | 11539875 |
| association of escherichia coli o157:h7 with preharvest leaf lettuce upon exposure to contaminated irrigation water. | recent foodborne outbreaks have linked infection by enterohemorrhagic escherichia coli (ehec) serotype o157:h7 to the consumption of contaminated lettuce. contamination via food handler error and on-the-farm contamination are thought to be responsible for several outbreaks. though recent studies have examined the application of ehec to store-bought lettuce, little is known about the attachment of ehec to growing plants. we investigated the association of lettuce seedlings with ehec o157:h7 strai ... | 2002 | 11808792 |
| "association of escherichia coli o157:h7 with preharvest leaf lettuce upon exposure to contaminated irrigation water," a comment on: j. food prot. 65(1):18-25 (2002). | | 2002 | 12030281 |
| effects of food materials on removal of allium-specific volatile sulfur compounds. | effects of food materials were investigated on removal of several kinds of thiols, sulfides, and disulfides, which arise from vegetables of allium species during food preparation and eating. methanethiol, propanethiol, and 2-propenethiol were captured by raw foods such as fruits, vegetables, and mushrooms or a mixture of their acetone powders and phenolic compounds. the odor of diallyl disulfide was remarkably reduced by kiwi fruit, spinach, cutting lettuce, parsley, basil, mushrooms, and, parti ... | 2002 | 12059171 |
| suspending lettuce type influences recoverability and radiation sensitivity of escherichia coli o157:h7. | an outbreak strain of escherichia coli o157:h7 was inoculated onto closely related but structurally distinct types of lettuce (lactuca sativa): boston (butterhead lettuce), iceberg (crisphead lettuce), and green leaf and red leaf (colored variants of looseleaf lettuce). the e. coli o157:h7 was inoculated either onto the surface of cut leaf pieces or into a homogenized leaf suspension. samples were gamma irradiated, and the radiation sensitivity of the inoculated bacteria was expressed as a d-val ... | 2002 | 12233847 |
| development of a toxic bait for control of eastern lubber grasshopper (orthoptera: acrididae). | this study assessed baits for eastern lubber grasshopper, romalea guttata (houttuyn). when offered a choice among several grain-based baits (rolled oats, wheat bran, oat bran, yeast, corn meal, cornflakes) and vegetable oils (canola, corn, peanut, soybean), eastern lubber grasshopper adults preferred bait consisting of wheat bran carrier with corn oil as an added phagostimulant. other carriers were accepted but consumed less frequently. discrimination by eastern lubber grasshoppers among oils wa ... | 2003 | 12852592 |
| efficacy of detergents in removing salmonella and shigella spp. from the surface of fresh produce. | fresh produce has been implicated in several foodborne disease outbreaks. produce surfaces can be primary sites of contamination during production and handling. one approach to reduce contamination is to treat fresh produce with rinsing agents. in this study, different detergent agents were used at 22 and 40 degrees c to determine their efficacy in removing salmonella and shigella spp. from the surfaces of strawberries, tomatoes, and green-leaf lettuce. produce was inoculated at 22 degrees c wit ... | 2003 | 14672215 |
| inhibition of pathogens on fresh produce by ultraviolet energy. | ultraviolet energy at a wavelength of 253.7 nm (uvc) was investigated for its bactericidal effects on the surface of red delicious apples, leaf lettuce and tomatoes inoculated with cultures of salmonella spp. or escherichia coli o157:h7. inoculated samples were subjected to different doses ranging from 1.5 to 24 mw/cm(2) of uvc and enumerated on tryptic soy agar plus 0.05 g/l nalidixic acid to determine effective log reductions of microbial populations. uvc applied to apples inoculated with e. c ... | 2004 | 14672825 |
| alkylperoxyl radical scavenging activity of red leaf lettuce (lactuca sativa l.) phenolics. | although lettuce may provide relatively low levels of antioxidative phytochemicals which may contribute to human health, lettuce leaf extracts in fact contained compounds with high specific peroxyl radical scavenging activities. after determining the extraction conditions that minimized phenolic oxidation and produced the highest oxygen radical absorbance capacity (orac) values, the phenolic compounds from red leaf lettuce were separated by reverse-phase high-performance liquid chromatography (h ... | 2003 | 14705882 |
| persistence of enterohemorrhagic escherichia coli o157:h7 in soil and on leaf lettuce and parsley grown in fields treated with contaminated manure composts or irrigation water. | outbreaks of enterohemorrhagic escherichia coli o157:h7 infections associated with lettuce and other leaf crops have occurred with increasing frequency in recent years. contaminated manure and polluted irrigation water are probable vehicles for the pathogen in many outbreaks. in this study, the occurrence and persistence of e. coli o157:h7 in soil fertilized with contaminated poultry or bovine manure composts or treated with contaminated irrigation water and on lettuce and parsley grown on these ... | 2004 | 15270487 |
| persistence of salmonella enterica serovar typhimurium on lettuce and parsley and in soils on which they were grown in fields treated with contaminated manure composts or irrigation water. | there are many sources of pathogen contamination of vegetable crops in the field that include manure used as fertilizer and irrigation water. an avirulent strain of salmonella enterica serovar typhimurium was added to three different types of composts-pm-5 (poultry manure compost), 338 (dairy manure compost), and nviro-4 (alkaline stabilized dairy manure compost)-and irrigation water at 10(7) colony forming units (cfu)/g and 10(5) cfu/ml, respectively, to determine under field conditions the per ... | 2004 | 15992259 |
| bacteriological quality of organically grown leaf lettuce in norway. | to investigate bacteriological quality in organically grown leaf lettuce, including the presence of selected pathogenic bacteria, and to obtain information about organic lettuce production, including fertilizing regimes. | 2005 | 16033519 |
| microbial survey of selected ontario-grown fresh fruits and vegetables. | recent produce-related outbreaks have been receiving heightened media coverage, which has increased public concern toward the safety of fresh fruits and vegetables. in response, the microbial contamination of ontario-grown fresh fruits and vegetables was evaluated by the ontario ministry of agriculture, food and rural affairs during the summer of 2004. prior to this survey, information specific to the microbial contamination of ontario-produced fruits and vegetables was limited. this nonregulato ... | 2007 | 18095445 |
| irradiation compared with chlorination for elimination of escherichia coli o157:h7 internalized in lettuce leaves: influence of lettuce variety. | pathogenic bacteria internalized in leaf tissues are not effectively removed by surface treatments. irradiation has been shown to inactivate leaf-internalized bacteria, but many aspects of targeting these protected pathogens remain unknown. bacterial cells of a cocktail mixture of 3 isolates of escherichia coli o157:h7 were drawn into the leaves of iceberg, boston, green leaf, and red leaf lettuce using vacuum perfusion. the inoculated leaves were treated with a 3-min wash with sodium hypochlori ... | 2008 | 18577002 |
| leafy vegetable mix supplementation improves lipid profiles and antioxidant status in c57bl/6j mice fed a high fat and high cholesterol diet. | daily consumption of an antioxidant-rich leafy vegetable mix (lvm) was assessed for beneficial effects on plasma lipid profiles, tissue lipid peroxidation, and oxidative dna damage in c57bl/6j mice fed a high fat and high cholesterol diet (20% fat and 1% cholesterol, wt/wt) for 4 weeks. the lvm contained beet leaf, angelica, red leaf lettuce, dandelion, green cos lettuce, lollo rosso, romaine lettuce (12.5%, respectively), scotch kale, and red kale (6.25%, respectively). the mice (n = 16) were r ... | 2009 | 19735190 |
| 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 ... | 2009 | 19833024 |
| whole-leaf wash improves chlorine efficacy for microbial reduction and prevents pathogen cross-contamination during fresh-cut lettuce processing. | currently, most fresh-cut processing facilities in the united states use chlorinated water or other sanitizer solutions for microbial reduction after lettuce is cut. freshly cut lettuce releases significant amounts of organic matter that negatively impacts the effectiveness of chlorine or other sanitizers for microbial reduction. the objective of this study is to evaluate whether a sanitizer wash before cutting improves microbial reduction efficacy compared to a traditional postcutting sanitizer ... | 2010 | 20629885 |
| assessing the cross contamination and transfer rates of salmonella enterica from chicken to lettuce under different food-handling scenarios. | cross contamination of foodborne pathogens from raw meats to ready-to-eat foods has caused a number of foodborne outbreaks. the cross contamination and transfer rates of salmonella enterica from chicken to lettuce under various food-handling scenarios were determined. the following scenarios were tested: in scenario 1, cutting board and knife used to cut chicken (10(6) cfu/g) were also used for cutting lettuce, without washing; in scenario 2, cutting board and knife were washed with water separa ... | 2010 | 20630321 |
| determination of free inositols and other low molecular weight carbohydrates in vegetables. | different low molecular weight carbohydrates including saccharides, polyalcohols, sugar acids, and glycosides have been identified and quantified in different edible vegetables from asteraceae, amarantaceae, amarylidaceae, brassicaceae, dioscoreaceae, and solanaceae families by gas chromatography-mass spectrometry. apart from glucose, fructose, and sucrose, other saccharides such as sedoheptulose in chicory, spinach, cabbage, purple yam, eggplant, radish, and oak leaf lettuce, rutinose in eggpla ... | 2011 | 21366313 |
| root-zone temperature and nitrogen affect the yield and secondary metabolite concentration of fall- and spring-grown, high-density leaf lettuce. | background: understanding the effects of temperature and nitrogen levels on key variables, particularly under field conditions during cool seasons of temperate climates, is important. here, we document the impact of root-zone heating and nitrogen (n) fertility on the accumulation and composition of fall- and spring-grown lettuce biomass. a novel, scalable field system was employed. results: direct-seeded plots containing a uniform, semi-solid, and nearly stable rooting medium were established ou ... | 2011 | 21842529 |
| Use of a common laboratory glassware detergent improves recovery of Cryptosporidium parvum and Cyclospora cayetanensis from lettuce, herbs and raspberries. | The success of any protocol designed to detect parasitic protozoa on produce must begin with an efficient initial wash step. Cryptosporidium parvum and Cyclospora cayetanensis oocysts were seeded onto herbs, lettuces and raspberries, eluted with one of four wash solutions and the recovered number of oocysts determined via fluorescent microscopy. Recovery rates for fluorescein thiosemicarbazide labeled C. parvum oocysts seeded onto spinach and raspberries and washed with de-ionized water were 38. ... | 2011 | 22094179 |
| 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 |
| sanitizer efficacy in preventing cross-contamination of heads of lettuce during retail crisping. | this study was conducted to provide information regarding mitigation of cross-contamination through the use of sanitizer during crisping at retail outlets. seven non-inoculated heads and one inoculated head (≈5 log cfu/g) of lettuce were placed into commercial sink filled with 76 l of tap water (tw), electrolyzed water (ew, free chlorine: 43 ± 6 ppm), lactic acid and phosphoric acid-based sanitizer (lpa, ph 2.89), or citric acid-based sanitizer (ca, ph 2.78) and soaked for 5 min. two subsequent ... | 2017 | 28213024 |
| comparative validation study to demonstrate the equivalence of a minor modification to aoac official method 2005.04 assurance gds e. coli 0157:h7 method to the reference culture method: 375 gram sample size. | the assurance gds escherichia coli (e. col) o157:h7, aoac official method 2005.04, has been modified to include a larger sample size of 375 g. a methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. ninety samples and controls, representing three foods, were analyzed. results show no statistically detectable difference between the assurance gds e. coli o157:h7 assay and the reference culture methods for the detection of e. col ... | 2013 | 24000751 |
| retention of quality and nutritional value of 13 fresh-cut vegetables treated with low-dose radiation. | improving the microbial safety while maintaining quality of fresh fruits and vegetables will increase consumer confidence in fresh produce. this study was conducted to investigate the effects of irradiation at 1 kgy, a dose that potentially inactivates e. coli o157:h7 by 5 logs, on the quality of 13 common fresh-cut vegetables: iceberg, romaine, green and red leaf lettuce, spinach, tomato, cilantro, parsley, green onion, carrot, broccoli, red cabbage, and celery. the results showed that the appe ... | 2008 | 18803730 |
| salmonella surveillance on fresh produce in retail in turkey. | although turkey is one of the major producers of fruits and vegetables in the world, there has been no information available on the prevalence of pathogens in fresh produce. to fill this gap, we collected 503 fresh produce samples including tomato, parsley, iceberg lettuce, green-leaf lettuce and five different fresh pepper varieties (i.e., green, kapya, bell, mazamort and charleston) from 3 major districts within 9 supermarkets and 3 bazaars in ankara, turkey to investigate the presence of salm ... | 2015 | 25643853 |
| molecular mapping of high resistance to bacterial leaf spot in lettuce pi 358001-1. | lettuce (lactuca sativa l.) is a diploid (2n = 18) with a genome size of 2,600 mbp, and belongs to the family compositae. bacterial leaf spot (bls), caused by xanthomonas campestris pv. vitians, is a major disease of lettuce worldwide. leaf lettuce pi 358001-1 has been characterized as an accession highly resistant to bls and has white seed. in order to understand inheritance of the high resistance in this germplasm line, an f3 population consisting of 163 families was developed from the cross p ... | 2016 | 27454703 |
| simultaneous determination of 70 pesticide residues in leek, leaf lettuce and garland chrysanthemum using modified quechers method with multi-walled carbon nanotubes as reversed-dispersive solid-phase extraction materials. | leek, leaf lettuce and garland chrysanthemum are troublesome vegetables containing large amount of pigments which may bring serious matrix interferences in mass spectrometry analysis. multi-walled carbon nanotubes (mwcnts) have a good effect for the cleanup of troublesome matrix. so the study was designed to develop a multi-residue method for the determination of 70 pesticide residues in leek, leaf lettuce and garland chrysanthemum based on a modified quechers procedure using mwcnts as reversed- ... | 2015 | 26513135 |
| yield loss assessments for cultivars of broccoli, lettuce, and onion exposed to ozone. | the effects of the photochemical oxidant air pollutant ozone (o(3)) on growth and yield of three garden crops, broccoli (brassica oleracea l.), lettuce (lactuca sativa l.), and onion (allium cepa l.) were studied in an open-top chamber experiment conducted in the field in southern california. four cultivars each of leaf lettuce, broccoli, and globe onion were exposed to charcoal-filtered air (cf), non-filtered (nf) air, or nf plus 1.5 times ambient o(3) concentration from 4 weeks after germinati ... | 1990 | 15092228 |
| growth of wheat and lettuce and enzyme activities of soils under garlic stalk decomposition for different durations. | garlic (allium sativum l.) stalk is a byproduct of garlic production that is normally thought of as waste but is now considered a useful biological resource. it is necessary to utilize this resource efficiently and reasonably to reduce environmental pollution and achieve sustainable agricultural development. | 2016 | 27753097 |
| reversal of dietary-induced hyperlipidemia in biomphalaria glabrata (gastropoda). | 1. to determine if dietary induced hyperlipidemia in snails could be reversed, thin-layer chromatography studies were done on lipids in the digestive gland-gonad (dgg) complex of biomphalaria glabrata fed either hen's egg yolk for 2 weeks (group a), yolk for 1 week followed by leaf lettuce for 1 week (group b), or lettuce for 2 weeks (group c). 2. the major lipid fractions in group a were triacylglycerols, phosphatidylethanolamine, and phosphatidylcholine, along with lesser amounts of sterol est ... | 1991 | 1682097 |
| dry deposition of gaseous radioiodine and particulate radiocaesium onto leafy vegetables. | radionuclides released to the atmosphere during dry weather (e.g. after a nuclear accident) may contaminate vegetable foods and cause exposure to humans via the food chain. to obtain experimental data for an appropriate assessment of this exposure path, dry deposition of radionuclides to leafy vegetables was studied under homogeneous and controlled greenhouse conditions. gaseous (131)i-tracer in predominant elemental form and particulate (134)cs-tracer at about 1 mum diameter were used to identi ... | 2009 | 19640563 |
| consumer sensory analysis of organically and conventionally grown vegetables. | consumers of organically grown fruits and vegetables often believe that these products taste better than conventional produce. however, comparison of produce from supermarket shelves does not permit adequate assessment of this consumer perception, given potentially confounding cultivar and environmental effects. we used replicated side-by-side plots to produce organic and conventional vegetables for consumer sensory studies. in one test, red loose leaf lettuce, spinach, arugula, and mustard gree ... | 2007 | 17995860 |
| comparative validation study to demonstrate the equivalence of a minor modification to aoac official method 2005.05 assurance gds shiga toxin genes (o157) method to the reference culture method: 375 gram sample size. | the assurance gds shiga toxin genes (0157), aoac official methodsm 2005.05, has been modified to include a larger sample size of 375 g. a methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. ninety samples and controls, representing three foods, were analyzed. results show no statistically detectable difference between the assurance gds escherichia coli o157:h7 assay and the reference culture methods for the detection of e. c ... | 2013 | 24000752 |
| fate of escherichia coli o157:h7 and salmonella in soil and lettuce roots as affected by potential home gardening practices. | the survival and distribution of enteric pathogens in soil and lettuce systems were investigated in response to several practices (soil amendment supplementation and reduced watering) that could be applied by home gardeners. | 2013 | 23893354 |
| biocontrol of escherichia coli o157: h7 on fresh-cut leafy greens. | the effect of a bacteriophage cocktail (ecoshield™) that is specific against escherichia coli o157:h7 was evaluated against a nalidixic acid-resistant enterohemorrhagic e. coli o157:h7 rm4407 (ehec) strain on leafy greens stored under either (1) ambient air or (2) modified atmosphere (ma; 5% o2/35% co2/60% n2). pieces (~2 × 2 cm(2)) of leafy greens (lettuce and spinach) inoculated with 4.5 log cfu/cm(2) ehec were sprayed with ecoshield™ (6.5 log pfu/cm(2)). samples were stored at 4 or 10°c for u ... | 2013 | 23819107 |
| incidence of naturally internalized bacteria in lettuce leaves. | lettuce is the fresh leafy vegetable most frequently involved in foodborne disease outbreaks. human bacterial pathogens may be experimentally internalized into lettuce plants, but the occurrence of natural microflora inside lettuce leaves has not been elucidated. to characterize the endophytic microorganism residing in commercial lettuce leaves, two separate studies were conducted. first, a total of 30 and 25 heads of romaine and red leaf lettuce, respectively, served as the source of individual ... | 2013 | 23454817 |
| presence of human pathogens in produce from retail markets in northern germany. | two hundred fresh produce samples (cucumber, carrots, herbs, leaf lettuce, and ready-to-eat mixed salad leaves) were obtained from retail in northern germany in 2015. these were investigated for microbial contamination and the presence of foodborne pathogens, including listeria monocytogenes, salmonella serovars, presumptive bacillus (b.) cereus, and shiga toxin-producing escherichia coli using culture-dependent (enrichment, plating on selective media) and -independent (real-time polymerase chai ... | 2017 | 28594569 |
| thallium contamination in arable soils and vegetables around a steel plant-a newly-found significant source of tl pollution in south china. | thallium (tl) is a highly toxic rare element. severe tl poisoning can cause neurological brain damage or even death. the present study was designed to investigate contents of tl and other associated heavy metals in arable soils and twelve common vegetables cultivated around a steel plant in south china, a newly-found initiator of tl pollution. potential health risks of these metals to exposed population via consumption of vegetables were examined by calculating hazard quotients (hq). the soils s ... | 0 | 28233568 |
| effect of cadmium accumulation on mineral nutrient levels in vegetable crops: potential implications for human health. | consumption of vegetables is often the predominant route whereby humans are exposed to the toxic metal cd. health impacts arising from cd consumption may be influenced by changes in the mineral nutrient content of vegetables, which may occur when plants are exposed to cd. here, we subjected model root (carrot) and leaf (lettuce) vegetables to soil cd concentrations of 0.3, 1.5, 3.3, and 9.6 μg g(-1) for 10 weeks to investigate the effect of cd exposure on cd accumulation, growth performance, and ... | 0 | 27411535 |
| greater adherence to the alternative healthy eating index is associated with lower incidence of physical function impairment in the nurses' health study. | physical function is integral to healthy aging, in particular as a core component of mobility and independent living in older adults, and is a strong predictor of mortality. limited research has examined the role of diet, which may be an important strategy to prevent or delay a decline in physical function with aging. | 0 | 27170727 |
| [distribution characteristics and risk assessment of phthalic acid esters in agricultural products around the pearl river delta. south china]. | in order to investigate and assess the distribution of pathalic acid easters (paes) in agricultural products from typical areas of the pearl river delta, south china, 131 agricultural products were sampled for determination of 6 paes priority pollutants classified by the u. s. epa by gc-fid. the results showed that the total contents of the paes (sigma paes) in agricultural products samples ranged from nd to 79.86 mg x kg(-1) and the mean value was 2.84 mg x kg(-1), with the detected ratio of 98 ... | 0 | 27078973 |
| stability of carotenoids and tocopherols in ready-to-eat baby-leaf lettuce and salad rocket during low-temperature storage. | minimally processed ready-to-eat baby-leaf vegetables (blvs) are the most convenient source to include the health beneficial bioactive in the daily diet. in the present study, the visual quality and storage stability of carotenoids, tocopherols were investigated in lettuce (green and red romaine) and salad rocket blvs. the commercially packed samples of blvs were stored at 0 °c and 4 °c in dark conditions and analyzed after 0, 2, 4, 8 and 12 days of storage. all the studied samples were found in ... | 0 | 27075434 |
| bioaccessibility of heavy metals in vegetables and its association with the physicochemical characteristics. | the bioaccessibilites of heavy metals in vegetables grown around a waste-incinerator site were estimated using the physiologically based extraction test (pbet) method, to assess potential health risk to the local consumers. the average gastric and intestinal bioaccessibilities of cd, cr, cu, ni, and pb in vegetables varied within 3.2-9.4 and 0.8-5.3 %, 1.4-2.3 and 1.1-1.9 %, 25-46 and 13-26 %, 6.6-30 and 2.6-5.3 %, 11-29 and 7.1-23 %, respectively. strong negative correlations were found between ... | 0 | 26564187 |
| occurrence sampling in a residence hall foodservice: cleaning times for selected vegetables. | objectives of this study were to analyze work functions in a vegetable pre-preparation unit of a large residence hall foodservice using occurrence sampling and to determine cleaning times for selected vegetables. data were collected in the early spring for 14 consecutive days. total hours worked were 349.5; 2,174 observations were recorded. percentage labor time and minutes expended were calculated for cleaning selected vegetables. average cleaning times were established for minutes per pound an ... | 1985 | 3968358 |
| in vitro bile acid binding capacities of red leaf lettuce and cruciferous vegetables. | in the present study, we tested the bile acid binding capacity of red leaf lettuce, red cabbage, red kale, green kale, and brussels sprouts through in vitro digestion process by simulating mouth, gastric, and intestinal digestion using six bile acids at physiological ph. green and red kale exhibited significantly higher (86.5 ± 2.9 and 89.7 ± 0.9%, respectively) bile acid binding capacity compared to the other samples. further, three different compositions of bile acids were tested to understand ... | 2017 | 28812344 |
| accumulation of heavy metals in leaf vegetables from agricultural soils and associated potential health risks in the pearl river delta, south china. | this study investigated the extent of heavy metal accumulation in leaf vegetables and associated potential health risks in agricultural areas of the pearl river delta (prd), south china. total concentrations of mercury (hg), cadmium (cd), lead (pb), chromium (cr) and arsenic (as) were determined in 92 pairs of soil and leaf vegetable (flowering chinese cabbage, lettuce, pakchoi, chinese cabbage, loose-leaf lettuce, and chinese leaf mustard) samples collected from seven agricultural areas (cities ... | 2014 | 24185814 |
| characterization of phenolic compounds in green and red oak-leaf lettuce cultivars by uhplc-dad-esi-qtof/ms using mse scan mode. | lettuce (lactuca sativa) is one of the most popular leafy vegetables in the world and constitutes a major dietary source of phenolic compounds with health-promoting properties. in particular, the demand for green and red oak-leaf lettuces has considerably increased in the last years but few data on their polyphenol composition are available. moreover, the usage of analytical edge technology can provide new structural information and allow the identification of unknown polyphenols. in the present ... | 2017 | 28833875 |
| impact of solar radiation exposure on phyllosphere bacterial community of red-pigmented baby leaf lettuce. | solar radiation has been identified as a stress factor affecting phyllosphere associated bacteria colonization and survival during primary production. in the present study, the impact of different solar radiation doses on the phyllosphere microbiota of red-pigmented baby leaf lettuce cultivated in open field under commercial conditions was evaluated. four weeks before harvest, the growing field was divided into four plots; each one was consecutively covered with one-week-interval with a light-ex ... | 2017 | 28576376 |
| reuse of organomineral substrate waste from hydroponic systems as fertilizer in open-field production increases yields, flavonoid glycosides, and caffeic acid derivatives of red oak leaf lettuce (lactuca sativa l.) much more than synthetic fertilizer. | effects of organic waste from a hydroponic system added with minerals (organomineral fertilizer) and synthetic fertilizer on major polyphenols of red oak leaf lettuce using hplc-dad-esi-ms(3) were investigated. interestingly, contents of the main flavonoid glycosides and caffeic acid derivatives of lettuce treated with organomineral fertilizer were equal to those synthesized without soil additives. this was found although soil nutrient concentrations, including that of nitrogen, were much lower ... | 2016 | 27606685 |
| co₂ enrichment can produce high red leaf lettuce yield while increasing most flavonoid glycoside and some caffeic acid derivative concentrations. | carbon dioxide (co2) enrichment is a common practice in greenhouses to increase crop yields up to 30%. yet, reports on the effect on foliar phenolic compounds vary. we studied the effect on two red leaf lettuce cultivars, grown for 25 days in growth chambers at co2 concentrations of 200 or 1,000 ppm, with some plants exchanged between treatments after 11 days. as expected, head mass increased with higher co2 concentration. regression analysis, corrected for head mass, showed increased concentrat ... | 2016 | 26776031 |
| weather variability influences color and phenolic content of pigmented baby leaf lettuces throughout the season. | the lack of consistency in homogeneous color throughout the season of pigmented baby leaf lettuce is a problem for growers because of the rejection of the product and consequently the economic loss. changes in color as well as individual and total phenolic composition and content as a response to the climatic variables were studied following the analysis of three pigmented baby leaf lettuces over 16 consecutive weeks from february to may, which corresponded to the most important production seaso ... | 2015 | 25650715 |
| freshly characterization and storability of mini head lettuces at optimal and abusive temperatures. | selection of lettuce varieties less sensitive to quality deterioration and more tolerant to abusive temperatures during handling, transportation, and storage is essential to minimize economical and quality losses that affect both producers and consumers. this work was focused on the quality changes of four baby head lettuces (lactuca sativa l.), two butter (red and green) and two oak-leaf (red and green) types, during storage at 0 ℃ and 10 ℃ for 10 days. lettuce quality was determined by measuri ... | 2016 | 25631488 |
| water-soluble compounds of lettuce inhibit dna damage and lipid peroxidation induced by glucose/serum deprivation in n2a cells. | oxidative stress, increase of lipid peroxidation and resultant dna damage are associated with pathophysiology of many human diseases such as acute and chronic cns injuries and diseases, cancer, and also aging. this work was done to investigate whether water fraction from the hydroalcoholic extract of green leaf lettuce (lactuca sativa l.) can protect n2a cells against glucose/serum deprivation (gsd)-induced lipid peroxidation and dna fragmentation. the cells were cultivated for 12 h in gsd condi ... | 2014 | 25265820 |
| physiological, phytochemical and structural changes of multi-leaf lettuce caused by salt stress. | environmental stress due to salt has been described to enhance lettuce processability, shelf life and consumer acceptability. moderate salinity causes altered leaf carotenoid, lignin, phenolic and flavonol levels without noticeable changes in the green colour and morphology of lettuce. the aim of this study was to understand the improvements in processability, due to salt stress, related to textural properties and structural characteristics. | 2014 | 24170602 |
| temporary reduction of radiation does not permanently reduce flavonoid glycosides and phenolic acids in red lettuce. | applying transparent daytime screens in greenhouses in cool seasons reduces the amount of energy needed for heating, but also the solar radiation available for crops. this can reduce yield and product quality of leafy vegetables because of constrained photosynthesis and altered biosynthesis. to study this, we cultivated five-week old red leaf lettuce (lactuca sativa l.) for four weeks in growth chambers under a photosynthetic photon flux density (ppfd) of 225 and 410 μmol m(-2) s(-1), respective ... | 2013 | 23735845 |
| led lighting and seasonality effects antioxidant properties of baby leaf lettuce. | we report on the application of supplementary light-emitting diode (led) lighting within a greenhouse for cultivation of red, green and light green leaf baby lettuces (lactuca sativa l.) grown under natural illumination and high-pressure sodium (hps) lamps (16-h; ppfd-170 μmol m(-2)s(-1)) during different growing season. supplementary lighting from blue 455/470 nm and green 505/530 nm leds was applied (16-h; ppfd-30 μmol m(-2)s(-1)). our results showed that to achieve solely a positive effect is ... | 2012 | 25005972 |
| effects of seasonal variation on sensory properties and total phenolic content of 5 lettuce cultivars. | butterhead, crisphead, green leaf, red leaf, and romaine types of lettuce (lactuca sativa l.) are all commonly available in u.s. markets. sensory properties of lettuce may vary in response to environmental factors that often fluctuate widely throughout the growing season. bitterness is generally thought to increase in lettuce grown at higher temperatures and may be related to phenolic content. this study evaluated sensory properties and total phenolic content of 5 lettuce cultivars harvested ear ... | 2010 | 20492312 |
| 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 ... | 2007 | 17894455 |
| 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 ... | 2007 | 17539550 |
| a system and methodology for measuring volatile organic compounds produced by hydroponic lettuce in a controlled environment. | a system and methodology were developed for the nondestructive qualitative and quantitative analysis of volatile emissions from hydroponically grown 'waldmann's green' leaf lettuce (lactuca sativa l.). photosynthetic photon flux (ppf), photoperiod, and temperature were automatically controlled and monitored in a growth chamber modified for the collection of plant volatiles. the lipoxygenase pathway products (z)-3-hexenal, (z)-3-hexenol, and (z)-3-hexenyl acetate were emitted by lettuce plants af ... | 1996 | 11539353 |
| effects of incandescent radiation on photosynthesis, growth rate and yield of 'waldmann's green' leaf lettuce. | effects of different ratios incandescent (ln) to fluorescent (fl) radiation were tested on growth of 'waldmann's green' leaf lettuce (lactuca sativa l.) in a controlled environment. after 4 days of treatment, dry weight, leaf area, relative growth rate (rgr), net assimilation rate (nar), leaf area ratio (lar) and photosynthetic rate (pn) were greater for plants grown at 84 rather than 16% of total irradiance (82 w m-2) from ln lamps. although leaf dry weight and area were 12-17% greater at 84% l ... | 1989 | 11539045 |
| effects of co2 and photosynthetic photon flux on yield, gas exchange and growth rate of lactuca sativa l. 'waldmann's green.' | enrichment of co2 to 46 mmol m-3 (1000 mm3 dm-3) at a moderate photosynthetic photon flux (ppf) of 450 micromoles m-2 s-1 stimulated fresh and dry weight gain of lettuce leaves 39% to 75% relative to plants at 16 mmol m-3 co2 (350 mm3 dm-3). relative growth rate (rgr) was stimulated only during the first several days of exponential growth. elevating co2 above 46 mmol m-3 at moderate ppf had no further benefit. however, high ppf of 880-900 micromoles m-2 s-1 gave further, substantial increases in ... | 1988 | 11539044 |
| growth and yield characteristics of 'waldmann's green' leaf lettuce under different photon fluxes from metal halide or incandescent + fluorescent radiation. | 'waldmann's green' leaf lettuce (lactuca sativa l.) was grown either under 84% irradiance from incandescent (in) + 16% from fluorescence (fl) lamps, or 100% from metal halide (mh) lamps, both at 392 micromoles s-1 m-2 of photosynthetically active radiation (400-700 nm) from 11 to 19 days after seeding. no differences in leaf dry weight, leaf area, relative growth rate (rgr) or photosynthesis (pn) occurred after 8 days of exposure to these radiation treatments for 20 h day-1. however, a 23% reduc ... | 1988 | 11539046 |
| stimulating productivity of hydroponic lettuce in controlled environments with triacontanol. | triacontanol (1-triacontanol) applied as a foliar spray at 10(-7) m to 4-day-old, hydroponically grown leaf lettuce (lactuca sativa l.) seedlings in a controlled environment increased leaf fresh and dry weight 13% to 20% and root fresh and dry weight 13% to 24% 6 days after application, relative to plants sprayed with water. when applied at 8 as well as 4 days after seeding, triacontanol increased plant fresh and dry weight, leaf area, and mean relative growth rate 12% to 37%. there was no benef ... | 1987 | 11539702 |
| effect of 16 and 24 hours daily radiation (light) on lettuce growth. | a 50% increase in total radiation by extending the photoperiod from 16 to 24 hr doubled the weight of all cultivars of loose-leaf lettuce (lactuca sativa l.) 'grand rapids forcing', 'waldmanns green', 'salad bowl', and 'rubyconn', but not a butterhead cultivar, 'salina'. when total daily radiation (moles of photons) was the same, plants under continuous radiation weighed 30% to 50% more than plants under a 16 hr photoperiod. by using continuous radiation on loose-leaf lettuce, fewer lamp fixture ... | 1986 | 11539771 |
| stimulation of lettuce productivity by manipulation of diurnal temperature and light. | 'salad bowl' and 'waldmann's green' leaf lettuce (lactuca sativa l.) were exposed to photosynthetic photon flux densities (ppfd) of 444 or 889 micromoles s-1 m-2 for 20 hours day-1 under a diurnal temperature regime of 25 degrees c days/15 degrees nights or 20 degrees days/15 degrees nights. leaf dry weight of both cultivars was highest under the high ppfd/warm temperature regime and lowest under the low ppfd/cool temperature regime. 'waldmann's green' yielded more than did 'salad bowl' at 889 m ... | 1983 | 11542283 |
| development and validation of an analytical method for multi-residue determination of pesticides in lettuce using quechers-uhplc-ms/ms. | a new analytical method for multi-residue determination of 16 multiclass pesticides in lettuce was developed using ultra high performance liquid chromatography with tandem mass spectrometry with a triple quadrupole mass analyzer and positive mode electrospray ionization, using a previously optimized quick, easy, cheap, effective, rugged, and safe method for sample preparation. validation studies, according to document sante/11945/2015, demonstrated that the developed method is selective, accurat ... | 2018 | 29293290 |
| investigation of bioaccessibility of cu, fe, mn, and zn in market vegetables in the colon using pbet combined with shime. | the in vitro bioaccessibility of trace metals associated with oral ingestion of market vegetables (lettuce, pak choi, cole, and leaf lettuce) of beijing, china was studied. the physiologically based extraction test (pbet) combined with the simulator of human intestinal microbial ecosystem (shime) was applied to simulate stomach, small intestine, and colon of human. in the gastro-intestinal phases, the bioaccessibility of cu, fe, mn, and zn varied within 5.7-75.5%, 17.3-50.4%, 13.3-49.1%, and 19. ... | 2017 | 29242507 |
| dissipation and residues of pyrethrins in leaf lettuce under greenhouse and open field conditions. | pyrethrins are nowadays widely used for prevention and control of insects in leaf lettuce. however, there is a concern about the pesticide residue in leaf lettuce. a reliable analytical method for determination of pyrethrins (pyrethrin-and п, cinerin і and п, and jasmolin і and п) in leaf lettuce was developed by using gas chromatography-mass spectrometry (gc-ms). recoveries of pyrethrins in leaf lettuce at three spiking levels were 99.4-104.0% with relative standard deviations of 0.9-3.1% (n = ... | 2017 | 28754023 |
| mitigating cadmium accumulation in greenhouse lettuce production using biochar. | greenhouse experiments were conducted to investigate the influence of rice straw biochar (rsb) on soil cadmium (cd) availability and accumulation in lettuce. the rsb was applied either in bands or broadcast in the test site of four greenhouses with soil cd concentrations ranging from 1.70-3.14 μg g-1. biochar doses applied in bands were half of those broadcast. the cd levels in the shoots of lettuce were observed to be reduced by up to 57% with increasing rsb application rate (0, 6, 12, 18 t ha- ... | 2017 | 28074369 |
| transcriptome analysis and anthocyanin-related genes in red leaf lettuce. | this study aimed to analyze the transcriptome profile of red lettuce and identify the genes involved in anthocyanin accumulation. red leaf lettuce is a popular vegetable and popular due to its high anthocyanin content. however, there is limited information available about the genes involved in anthocyanin biosynthesis in this species. in this study, transcriptomes of 15-day-old seedlings and 40-day-old red lettuce leaves were analyzed using an illuminia hiseqtm 2500 platform. a total of 10.6 gb ... | 2016 | 26909931 |
| nitrogen limited red and green leaf lettuce accumulate flavonoid glycosides, caffeic acid derivatives, and sucrose while losing chlorophylls, β-carotene and xanthophylls. | reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. the reason for this is still under discussion. the plants' response to low nitrogen concentration can interact with other factors, for example radiation intensity. we cultivated red and green leaf lettuce hydroponically in a mediterranean greenhouse, supplying three different levels of nitroge ... | 2015 | 26569488 |
| variation of the pseudomonas community structure on oak leaf lettuce during storage detected by culture-dependent and -independent methods. | the genus pseudomonas plays an important role in the lettuce leaf microbiota and certain species can induce spoilage. the aim of this study was to investigate the occurrence and diversity of pseudomonas spp. on oak leaf lettuce and to follow their community shift during a six day cold storage with culture-dependent and culture-independent methods. in total, 21 analysed partial pseudomonas 16s rrna gene sequences matched closely (> 98.3%) to the different reference strain sequences, which were di ... | 2016 | 26425802 |
| effect of aerated compost tea on the growth promotion of lettuce, soybean, and sweet corn in organic cultivation. | this study investigated the chemical characteristics and microbial population during incubation of four kinds of aerated compost teas based on oriental medicinal herbs compost, vermicompost, rice straw compost, and mixtures of three composts (movr). it aimed to determine the effects of the aerated compost tea (act) based on movr on the growth promotion of red leaf lettuce, soybean and sweet corn. findings showed that the ph level and ec of the compost tea slightly increased based on the incubati ... | 2015 | 26361474 |
| estimated daily intake and seasonal food sources of quercetin in japan. | quercetin is a promising food component, which can prevent lifestyle related diseases. to understand the dietary intake of quercetin in the subjects of a population-based cohort study and in the japanese population, we first determined the quercetin content in foods available in the market during june and july in or near a town in hokkaido, japan. red leaf lettuce, asparagus, and onions contained high amounts of quercetin derivatives. we then estimated the daily quercetin intake by 570 residents ... | 2015 | 25849945 |
| concentration and transportation of heavy metals in vegetables and risk assessment of human exposure to bioaccessible heavy metals in soil near a waste-incinerator site, south china. | there is limited study focusing on the bioaccumulation of heavy metals in vegetables and human exposure to bioaccessible heavy metals in soil. in the present study, heavy metal concentrations (cr, ni, cu, pb and cd) were measured in five types of vegetables, soil, root, and settled air particle samples from two sites (at a domestic waste incinerator and at 20km away from the incinerator) in guangzhou, south china. heavy metal concentrations in soil were greater than those in aerial parts of vege ... | 2015 | 25829292 |
| unlike quercetin glycosides, cyanidin glycoside in red leaf lettuce responds more sensitively to increasing low radiation intensity before than after head formation has started. | this study investigated the effect of low-level photosynthetic photon flux density (ppfd; 43-230 μmol m(-2) s(-1)) on the major phenolic compounds of red leaf lettuce in three growth stages, before, during, and after head formation, using hplc-dad-esi-ms(2) and evaluating via multiple regression analysis. generally, the light-related increase of flavonoid glycosides was structure and growth stage-dependent. in detail, an interaction was detected between plant age and ppfd regarding cyanidin-3-o- ... | 2014 | 24382136 |
| cool-cultivated red leaf lettuce accumulates cyanidin-3-o-(6″-o-malonyl)-glucoside and caffeoylmalic acid. | cultivating lettuce in greenhouses at low temperatures improves its co2-balance and may increase its content of flavonoid glycosides and phenolic acids. we cultivated 5weeks old red leaf lettuce seedlings at 20/15°c (day/night) or 12/7°c until plants reached comparable growth stages: small heads were harvested after 13 (warm) and 26 (cool)days, while mature heads were harvested after 26 (warm) or 52 (cool)days. additionally, some plants were cultivated first cool then warm and vice versa (39days ... | 2014 | 24176360 |
| lettuce production and antioxidant capacity are differentially modified by salt stress and light intensity under ambient and elevated co2. | as a consequence of the increasing importance of vegetables in the human diet, there is an interest in enhancing both the productivity and quality of vegetables. a number of factors, including plant genotype and environmental growing conditions, can impact the production and quality of vegetables. the objective of this study was to determine whether elevated co2, salinity, or high light treatments assayed individually, or salinity or high light in combination with elevated co2, increased biomass ... | 2013 | 23838124 |
| predicting perchlorate uptake in greenhouse lettuce from perchlorate, nitrate, and chloride irrigation water concentrations. | perchlorate (clo) has been detected in edible leafy vegetables irrigated with colorado river water. the primary concern has been the clo concentration in lettuce ( l. var. l.). there has been a limited number of studies on clo uptake, but the interactive effect of other anions on clo uptake is not known in detail. we conducted a greenhouse clo uptake experiment using two types of lettuce (iceberg and butterhead) to investigate the interaction of uptake of clo, cl, and no on clo uptake under cont ... | 2013 | 23673756 |
| led illumination affects bioactive compounds in romaine baby leaf lettuce. | the effect of light quality on phytochemicals in romaine baby leaf lettuce 'thumper' was investigated in (i) a closed environment and (ii, iii) a greenhouse (16 h, 21/17 °c): (i) basal (638, 455, 660, 735 nm) leds supplemented with uv (380 nm), green (510 nm), yellow (595 nm) or orange (622 nm) leds (ppfd of ∼175 µmol m(-2) s(-1) ); (ii) high-pressure sodium (hps) lamps (90 µmol m(-2) s(-1) ) supplemented with blue (455, 470nm) or green (505, 530nm) leds (30 µmol m(-2) s(-1) ); (iii) at 3 days b ... | 2013 | 23584932 |
| nutritional yield: a proposed index for fresh food improvement illustrated with leafy vegetable data. | consumer interest in food products, including fresh vegetables, with health promoting properties is rising. in fresh vegetables, these properties include vitamins, minerals, dietary fiber, and secondary compounds, which collectively impart a large portion of the dietary, nutritional or health value associated with vegetable intake. many, including farmers, aim to increase the health-promoting properties of fresh vegetables on the whole but they face at least three obstacles. first, describing cr ... | 2012 | 22922881 |
| effects of exogenous abscisic acid on yield, antioxidant capacities, and phytochemical contents of greenhouse grown lettuces. | antioxidants and phytochemicals in vegetables are known to provide health benefits. strategies that enhance these properties are expected to increase the nutritional values of vegetables. the objective of this research is to assess the effects of exogenous abscisic acid (aba) on yield, antioxidant capacities, and phytochemical content of lettuces grown in a greenhouse. red loose leaf lettuce (cv. galactic) and green loose leaf lettuce (cv. simpson elite) were cultivated using a randomized comple ... | 2010 | 20420437 |
| a new quantitative and low-cost determination method of nitrate in vegetables, based on deconvolution of uv spectra. | a new uv-spectrophotometric method for the determination of nitrate in vegetables is presented. the method is based on the spectral deconvolution: uv spectrum of a sample is considered as a linear combination of absorption spectra, named reference spectra. the combination of a small number of spectra of reference allows to reconstitute the shape of uv spectrum of an unknown sample. there have been several fresh vegetables (lettuce, curly lettuce, oak-leaf lettuce), as well as frozen spinaches th ... | 2008 | 18656681 |
| changes in the flavonoid and phenolic acid contents and antioxidant activity of red leaf lettuce (lollo rosso) due to cultivation under plastic films varying in ultraviolet transparency. | red leaf lettuce (lollo rosso) was grown under three types of plastic films that varied in transparency to uv radiation (designated as uv block, uv low, and uv window). flavonoid composition was determined by high-performance liquid chromatography (hplc), total phenolics by the folin-ciocalteu assay, and antioxidant capacity by the oxygen radical absorbance capacity (orac) assay. exposure to increased levels of uv radiation during cultivation caused the leaves to redden and increased concentrati ... | 2007 | 18001028 |
| antioxidant capacity of leafy vegetables as affected by high tunnel environment, fertilisation and growth stage. | this study was conducted to evaluate the influences of protected environment, organic fertilisation and growth stage on the oxygen radical absorbance capacity (orac) values of leafy vegetables. | 2007 | 20836178 |
| effect of transpiration on pb uptake by lettuce and on water soluble low molecular weight organic acids in rhizosphere. | the effect of transpiration (high and low) on pb uptake by leaf lettuce and on water soluble low molecular weight organic acids (lmwoas) in rhizosphere has been studied. after two weeks of growth the plants were cultured in greenhouse for more four weeks and two days. pb(no(3))(2) solutions of different concentrations (100, 200, and 300 mg l(-1) of pb) were then added to the quartz sand pots of different plants and studies were initiated. blank experiments (without treating the quartz sand pots ... | 2006 | 16554084 |
| phytochemical phenolics in organically grown vegetables. | fruit and vegetable intake is inversely correlated with risks for several chronic diseases in humans. phytochemicals, and in particular, phenolic compounds, present in plant foods may be partly responsible for these health benefits through a variety of mechanisms. since environmental factors play a role in a plant's production of secondary metabolites, it was hypothesized that an organic agricultural production system would increase phenolic levels. cultivars of leaf lettuce, collards, and pac c ... | 2005 | 16302198 |
| toxic potential of oleander derived compost and vegetables grown with oleander soil amendments. | california recycles 50% of previously disposed trash. increased use of yardwastes and composts has raised concern about toxic materials in these products. oleander is a toxic shrub common to ca landscapes and is frequently clipped and disposed of in greenwaste containers, resulting in concerns about the toxicity of oleander-contaminated yardwastes and composts from these wastes. information about breakdown of oleandrin (one of the glycoside toxicants of oleander) during composting or the ability ... | 2003 | 12882497 |
| predicting lettuce canopy photosynthesis with statistical and neural network models. | an artificial neural network (nn) and a statistical regression model were developed to predict canopy photosynthetic rates (pn) for 'waldman's green' leaf lettuce (latuca sativa l.). all data used to develop and test the models were collected for crop stands grown hydroponically and under controlled-environment conditions. in the nn and regression models, canopy pn was predicted as a function of three independent variables: shootzone co2 concentration (600 to 1500 micromoles mol-1), photosynthet ... | 1998 | 11542672 |