A real-time PCR assay for detection and quantification of Verticillium dahliae in spinach seed.

Science.gov (United States)

Duressa, Dechassa; Rauscher, Gilda; Koike, Steven T; Mou, Beiquan; Hayes, Ryan J; Maruthachalam, Karunakaran; Subbarao, Krishna V; Klosterman, Steven J

2012-04-01

Verticillium dahliae is a soilborne fungus that causes Verticillium wilt on multiple crops in central coastal California. Although spinach crops grown in this region for fresh and processing commercial production do not display Verticillium wilt symptoms, spinach seeds produced in the United States or Europe are commonly infected with V. dahliae. Planting of the infected seed increases the soil inoculum density and may introduce exotic strains that contribute to Verticillium wilt epidemics on lettuce and other crops grown in rotation with spinach. A sensitive, rapid, and reliable method for quantification of V. dahliae in spinach seed may help identify highly infected lots, curtail their planting, and minimize the spread of exotic strains via spinach seed. In this study, a quantitative real-time polymerase chain reaction (qPCR) assay was optimized and employed for detection and quantification of V. dahliae in spinach germplasm and 15 commercial spinach seed lots. The assay used a previously reported V. dahliae-specific primer pair (VertBt-F and VertBt-R) and an analytical mill for grinding tough spinach seed for DNA extraction. The assay enabled reliable quantification of V. dahliae in spinach seed, with a sensitivity limit of ≈1 infected seed per 100 (1.3% infection in a seed lot). The quantification was highly reproducible between replicate samples of a seed lot and in different real-time PCR instruments. When tested on commercial seed lots, a pathogen DNA content corresponding to a quantification cycle value of ≥31 corresponded with a percent seed infection of ≤1.3%. The assay is useful in qualitatively assessing seed lots for V. dahliae infection levels, and the results of the assay can be helpful to guide decisions on whether to apply seed treatments.

Sampling Plans for the Thrips Frankliniella schultzei (Thysanoptera: Thripidae) in Three Lettuce Varieties.

Science.gov (United States)

Silva, Alisson R; Rodrigues-Silva, Nilson; Pereira, Poliana S; Sarmento, Renato A; Costa, Thiago L; Galdino, Tarcísio V S; Picanço, Marcelo C

2017-12-05

The common blossom thrips, Frankliniella schultzei Trybom (Thysanoptera: Thripidae), is an important lettuce pest worldwide. Conventional sampling plans are the first step in implementing decision-making systems into integrated pest management programs. However, this tool is not available for F. schultzei infesting lettuce crops. Thus, the objective of this work was to develop a conventional sampling plan for F. schultzei in lettuce crops. Two sampling techniques (direct counting and leaf beating on a white plastic tray) were compared in crisphead, looseleaf, and Boston lettuce varieties before and during head formation. The frequency distributions of F. schultzei densities in lettuce crops were assessed, and the number of samples required to compose the sampling plan was determined. Leaf beating on a white plastic tray was the best sampling technique. F. schultzei densities obtained with this technique were fitted to the negative binomial distribution with a common aggregation parameter (common K = 0.3143). The developed sampling plan is composed of 91 samples per field and presents low errors in its estimates (up to 20%), fast execution time (up to 47 min), and low cost (up to US $1.67 per sampling area). This sampling plan can be used as a tool for integrated pest management in lettuce crops, assisting with reliable decision making in different lettuce varieties before and during head formation. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Pesticide Residues in Commercial Lettuce, Onion, and Potato Samples From Bolivia—A Threat to Public Health?

DEFF Research Database (Denmark)

Skovgaard, Marlene; Renjel, Susana; Jensen, Olaf Chresten

2017-01-01

lettuce samples from La Paz were sampled on August 15, 2015 at a local market and screened for 283 pesticides. Residues of cypermethrin, chlorpyrifos, difenoconazol, or/and λ-cyhalothrin were detected in 50% of the lettuce samples, whereas no pesticides were found in potatoes and onions. In 20......% of the lettuce samples, the measurements were above the maximum residue limits, and 2 or 3 pesticides were identified simultaneously. Washing almost halved the pesticide levels, but still 20% of the samples showed measurements above the limits. No samples contained concentrations of pesticides which alone...

Plant-mediated restriction of Salmonella enterica on tomato and spinach leaves colonized with Pseudomonas plant growth-promoting rhizobacteria.

Science.gov (United States)

Hsu, Chiun-Kang; Micallef, Shirley A

2017-10-16

Reducing Salmonella enterica association with plants during crop production could reduce risks of fresh produce-borne salmonellosis. Plant growth-promoting rhizobacteria (PGPR) colonizing plant roots are capable of promoting plant growth and boosting resistance to disease, but the effects of PGPR on human pathogen-plant associations are not known. Two root-colonizing Pseudomonas strains S2 and S4 were investigated in spinach, lettuce and tomato for their plant growth-promoting properties and their influence on leaf populations of S. enterica serovar Newport. Plant roots were inoculated with Pseudomonas in the seedling stage. At four (tomato) and six (spinach and lettuce) weeks post-germination, plant growth promotion was assessed by shoot dry weight (SDW) and leaf chlorophyll content measurements. Leaf populations of S. Newport were measured after 24h of leaf inoculation with this pathogen by direct plate counts on Tryptic Soy Agar. Root inoculation of spinach cv. 'Tyee', with Pseudomonas strain S2 or S4 resulted in a 69% and 63% increase in SDW compared to non-inoculated controls (pgrowth by over 40% compared to controls (pgrowth promotion was detected in tomato cv. 'BHN602', but S2-inoculated plants had elevated leaf chlorophyll content (13%, pgrowth, but also reduce the fitness of epiphytic S. enterica in the phyllosphere. Plant-mediated effects induced by PGPR may be an effective strategy to minimize contamination of crops with S. enterica during cultivation. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of various conventional methods for sampling weeds in potato and spinach crops

Directory of Open Access Journals (Sweden)

David Jamaica

2014-04-01

Full Text Available This study aimed to evaluate (at an exploratory level, some of the different conventional sampling designs in a section of a potato crop and in a commercial crop of spinach. Weeds were sampled in a 16 x 48 m section of a potato crop with a set grid of 192 sections. The cover and density of the weeds were registered in squares of from 0.25 to 64 m². The results were used to create a database that allowed for the simulation of different sampling designs: variables and square size. A second sampling was carried out with these results in a spinach crop of 1.16 ha with a set grid of 6 x 6 m cells, evaluating the cover in 4 m² squares. Another database was created with this information, which was used to simulate other sampling designs such as distribution and quantity of sampling squares. According to the obtained results, a good method for approximating the quantity of squares for diverse samples is 10-12 squares (4 m² for richness per ha and 18 or more squares for abundance per hectare. This square size is optimal since it allows for a sampling of more area without losing sight of low-profile species, with the cover variable best representing the abundance of the weeds.

Preharvest internalization of Escherichia coli O157:H7 into lettuce leaves, as affected by insect and physical damage.

Science.gov (United States)

Erickson, Marilyn C; Liao, Jean; Payton, Alison S; Riley, David G; Webb, Cathy C; Davey, Lindsey E; Kimbrel, Sophia; Ma, Li; Zhang, Guodong; Flitcroft, Ian; Doyle, Michael P; Beuchat, Larry R

2010-10-01

Environmental pests may serve as reservoirs and vectors of zoonotic pathogens to leafy greens; however, it is unknown whether insect pests feeding on plant tissues could redistribute these pathogens present on the surface of leaves to internal sites. This study sought to differentiate the degree of tissue internalization of Escherichia coli O157:H7 when applied at different populations on the surface of lettuce and spinach leaves, and to ascertain whether lettuce-infesting insects or physical injury could influence the fate of either surface or internalized populations of this enteric pathogen. No internalization of E. coli O157:H7 occurred when lettuce leaves were inoculated with 4.4 log CFU per leaf, but it did occur when inoculated with 6.4 log CFU per leaf. Internalization was statistically greater when spinach leaves were inoculated on the abaxial (underside) than when inoculated on the adaxial (topside) side, and when the enteric pathogen was spread after surface inoculation. Brief exposure (∼18 h) of lettuce leaves to insects (5 cabbage loopers, 10 thrips, or 10 aphids) prior to inoculation with E. coli O157:H7 resulted in significantly reduced internalized populations of the pathogen within these leaves after approximately 2 weeks, as compared with leaves not exposed to insects. Surface-contaminated leaves physically injured through file abrasions also had significantly reduced populations of both total and internalized E. coli O157:H7 as compared with nonabraded leaves 2 weeks after pathogen exposure.

Evaluation of sanitary quality of lettuce (Lactuca sativa, L. irrigated with reused water in comparison with commercialized lettuce

Directory of Open Access Journals (Sweden)

Claudinei Fonseca Souza

2011-08-01

Full Text Available Inadequate use of water resources reduces their availability and therefore, research focused on their reutilization is required. This work evaluated the sanitary quality of lettuce irrigated with reused water in comparison with samples of lettuce commercialized in Taubaté (SP market. An experiment was developed in a greenhouse with three beds of lettuce irrigated with reused water and three beds of lettuce irrigated with urban water supply. After lettuce biological cycle had been completed, lettuce samples were collected from the beds (irrigated and non-irrigated with reused water and from samples of lettuce commercialized in the city market that were analyzed in the laboratory. The analyses were done using the multiple tubes methodology. The results showed that the samples from lettuce irrigated with urban water supply were not contaminated by either total or thermotolerant coliforms while samples of irrigated lettuce with reused water were contaminated by total coliforms. Samples from commercialized lettuce were contaminated by both kinds of coliforms. Results indicated that the application of reused water for agricultural purposes should occur only after carefully treatment to allow a safe use and to contribute to the water use sustainability.

Dry deposition of radionuclides on leafy vegetables

International Nuclear Information System (INIS)

Heuberger, H.; Tschiersch, J.; Shinonaga, T.; Bunzl, K.; Pliml, A.; Dietl, F.; Keusch, M.

2004-01-01

The dry deposition of gaseous elemental radio-iodine and particulate radio-caesium on mature leafy vegetable was studied in chamber experiments. The simultaneous exposition of endive, head lettuce, red oak leaf lettuce and spinach (spring leafy vegetable) rsp. curly kale, white cabbage and spinach (summer leafy vegetable) was performed under homogeneous and controlled conditions. The sample collective of each species was such large that for the expected variation of the results a statistically firm analysis was possible. Significant differences were observed for the 131 I deposition on spring vegetable: the deposition on spinach was roughly 3times that on leaf lettuce, 4times that on endive and 9times that on head lettuce. For 134 Cs, there was no significant difference between spinach and leaf lettuce, about twice the amount was deposited on both species as on endive and 3times as on head lettuce. All summer vegetables showed differences in deposition. For lodine, the deposition on spinach was roughly 3times (6times) that on curly kale and 35times (100times) that on white cabbage in the 2 experiments. For caesium, the deposition to curly kale was highest, about twice that on spinach and 35times (80times) that on white cabbage. The deposition velocity could be estimated, in average it was about 8times higher for 131 I than for 134 Cs. The influence of the particle size on the deposition velocity was small in the considered size range. Washing could reduce the contamination by about 10% for 131 I and 45% for 134 Cs. (orig.)

The Effect of Repeated Irrigation with Water Containing Varying Levels of Total Organic Carbon on the Persistence of Escherichia coli O157:H7 on Baby Spinach

Science.gov (United States)

The California lettuce and leafy greens industry has adopted the Leafy Greens Marketing Agreement (LGMA), which allows for 126 Most Probable Number (MPN) generic E. coli/100ml in irrigation water. Repeat irrigation of baby spinach plants with water containing E. coli O157:H7 and different levels of...

Reasoned opinion on the modification of the existing MRLs for indoxacarb in various salad plants and in spinach-like plants

OpenAIRE

European Food Safety Authority

2013-01-01

In accordance with Article 6 of Regulation (EC) No 396/2005, Belgium, hereafter referred to as the evaluating Member State (EMS), compiled an application to modify the existing MRLs for the active substance indoxacarb in rucola, cress, land cress, red mustard, other lettuce and salad plants, purslane (including sorrel and glassworth), beet leaves and other spinach and similar (leaves). In order to accommodate for the intended uses of indoxacarb, Belgium proposed to raise the existing MRLs fro...

Interlaboratory comparison of environmental relevant nuclides with spinach powder as sample medium; Vergleichspruefung mit Spinatpulver als Probenart fuer umweltrelevante Nuklide

Energy Technology Data Exchange (ETDEWEB)

Roos, N.; Tait, D. [Max Rubner-Institut, Kiel (Germany). Leitstelle fuer Boden, Bewuchs, Futtermittel und Nahrungsmittel pflanzlicher und tierischer Herkunft

2014-01-20

Spinach is cited as a representative medium for leafy vegetables in the Integrated Measurement and Information System for the surveillance of environmental radioactivity (IMIS) in Germany. Fresh spinach, however, is not suitable in interlaboratory comparisons on the determination of spiked radionuclides because of the difficulties in homogeneously distributing the radionuclides and attaining a known specific activity in the samples. In contrast, spinach powder is finely milled, so that homogeneous distribution and known specific activities of the nuclides are more readily achievable. For this interlaboratory comparison spinach powder was mixed with the pure beta emitter Sr-90 and the gamma-emitting nuclides I-131, Cs-134 and Cs-137. After homogenization samples were dispatched to 77 laboratories from Germany and other European countries (59 in Germany, 5 in Switzerland, 4 each in the UK and Austria, and one each in France, Italy, the Netherlands, Ireland and Luxembourg). In addition to the added nuclides participants had to determine the natural radionuclide K-40. The participants were instructed to use a fast method for the determination of dry matter (DM). To check the homogeneity of the nuclide distribution 14 samples of the labeled spinach powder were randomly selected and analyzed in the Coordinating Laboratory for the Surveillance of Radioactivity in the Environment of the Max Rubner-Institute (MRI). According to DIN 13528:2005 the samples showed sufficient homogeneity of the added nuclides. For the evaluation of the interlaboratory comparison the Physikalisch-Technische Bundesanstalt (PTB) determined reference values for the the specific activities (Bq per kg DM) of the gamma emitters. The values with the expanded uncertainties (k = 2) were as follows: I-131: 181 ± 6 Bq/kg; Cs-134: 34.4 ± 1.1 Bq/kg; Cs-137: 11.1 ± 0.4 Bq/kg; K-40: 1240 ± 40 Bq/kg. Since a reference value of the PTB for the specific activity of Sr-90 was not available the general average

Kinetic thermal degradation of vitamin C during microwave drying of okra and spinach.

Science.gov (United States)

Dadali, Gökçe; Ozbek, Belma

2009-01-01

In this present study, the effect of microwave output power and sample amount on vitamin C loss in okra (Hibiscus esculenta L.) and spinach (Spinacia oleracea L.) were investigated using the microwave drying technique. The procedure is based on the reaction between l-ascorbic acid (vitamin C) and 2,6-dichloroindophenol. The proposed method was applied successfully to both okra and spinach for the determination of ascorbic acid (vitamin C) content. It was observed that as the microwave output power increased or as the sample amount decreased, the vitamin C in okra and spinach decreased as well. The activation energy for degradation of vitamin C for both okra and spinach was calculated using an exponential expression based on the Arrhenius equation.

Chemical weed control in Spinach (Spiniacia oleracea

Directory of Open Access Journals (Sweden)

A. Modhej

2016-03-01

Full Text Available Introduction Spinach (Spinacia oleracea is an annual plant of family Chenopodiaceae. It is cultivated in temperate and cold regions in Khouzestan in autumn and winter. Weeds are the main problems that limit the production of vegetables. Competition ability of spinach against weeds is very low and weeds cause the loss of quality and quantity in this plant. Weeds reduce germination and establishment and growth of spinach. Weed management in spinach should be done at the beginning of the season. Hand weeding is the best way to control weeds spinach, although due to the high cost it is not cost effective, but is steel common in large areas. Weed control spinach, using chemical methods, the number of weeds are kept below the threshold of economic damage. Materials and Methods The experiment was conducted in a randomized complete block design with 15 treatments and three replications. Treatments included pre-plant application of EPTC at 5 and 6 lit ha-1, pre-plant application of Trifluralin at 2 lit ha-1, pre-plant and pre-emergence application of Pendimethalin at 3 lit ha-1, pre-emergence and post-emergence application of Meteribouzin at 300 g ha-1, pre-emergence and post-emergence application of Meteribouzin at 400 g ha-1, pre-emergence and post-emergence application of Imazethapyr at 0.7 lit ha-1, pre-emergence and post-emergence application of Imazethapyr at 1 lit ha-1, weedy and weed free checks. Each plot the size of 2.5 × 2 meters and 10 row cultivation with distances between rows of 15 cm and the distance between the plants 25 cm and the sowing depth was 3 cm. The herbicide treatments were applied to the back sprayer with Flat fan nozzle with volume of consumption of 240 lit ha-1 solution. The final harvest was about 50 days after emergence. Sampling of weeds 10 days before harvest was performed with using quadrate 0.5 ×0.5. Results Discussion Important broad-leaf and narrow leaf weeds observed in the field, included field bindweed

Differences in the dry deposition of gaseous elemental I-131 to several leafy vegetable species

International Nuclear Information System (INIS)

Shinonaga, T.; Heuberger, H.; Tschiersch, J.

2004-01-01

The height of the dry deposition of gaseous elemental 131 I to leafy vegetable is quite uncertain because of the different habit, surface texture and leaf uptake of the different plant species. There is no comparative data on the deposition to various species, but leafy vegetables are taken as reference plants for the estimation of the height of contamination of vegetable foods after a nuclear accident. Therefore new chamber experiments were performed to determine under homogeneous and controlled conditions the dry deposition of gaseous elemental 131 I on mature leafy vegetable. The simultaneous exposition of endive, head lettuce, red oak leaf lettuce and spinach (spring leafy vegetable) rsp. curly kale, white cabbage and spinach (summer leafy vegetable) was arranged. The sample collective of each species was such large that for the expected variation of the results a statistically firm analysis was possible. Significant differences were observed for the 131 I deposition on spring vegetable: the deposition on spinach was roughly 3 times that on leaf lettuce, 4 times that on endive and 9 times that on head lettuce. All summer vegetables showed differences in deposition. For Iodine, the deposition on spinach was roughly 3 times (6 times) that on curly kale and 35 times (100 times) that on white cabbage in the 2 experiments. Washing by deionised water could reduce the contamination only by about 10% for 131 I. (author)

Sensitivity of Pseudomonas fluorescens to gamma irradiation following surface inoculations on romaine lettuce and baby spinach

Science.gov (United States)

Irradiation of fresh fruits and vegetables is a post-harvest intervention measure often used to inactivate pathogenic food-borne microbes. We evaluated the sensitivity of Pseudomonas fluorescens strains (2-79, Q8R1, Q287) to gamma irradiation following surface inoculations on romaine lettuce and spi...

76 FR 38037 - Mevinphos; Data Call-in Order for Pesticide Tolerances

Science.gov (United States)

2011-06-29

..., strawberries, grapes, lettuce, melons, watermelon, peas, peppers, summer squash, cucumbers, and tomatoes (40..., spinach, summer squash, strawberries, and tomatoes); and 5. Processing Study (tomatoes) (860.1520). III..., cabbage, cauliflower, celery, grapes, lettuce, peas, peppers, spinach, summer squash, strawberries, and...

Distinguishing Bovine Fecal Matter on Spinach Leaves Using Field Spectroscopy

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Colm D. Everard

2016-08-01

Full Text Available Detection of fecal contaminants on leafy greens in the field will allow for decreasing cross-contamination of produce during and post-harvest. Fecal contamination of leafy greens has been associated with Escherichia coli (E. coli O157:H7 outbreaks and foodborne illnesses. In this study, passive field spectroscopy measuring reflectance and fluorescence created by the sun’s light, coupled with numerical normalization techniques, are used to distinguish fecal contaminants on spinach leaves from soil on spinach leaves and uncontaminated spinach leaf portions. A Savitzky-Golay first derivative transformation and a waveband ratio of 710:688 nm as normalizing techniques were assessed. A soft independent modelling of class analogies (SIMCA procedure with a 216 sample training set successfully predicted all 54 test set sample types using the spectral region of 600–800 nm. The ratio of 710:688 nm along with set thresholds separated all 270 samples by type. Application of these techniques in-field to avoid harvesting of fecal contaminated leafy greens may lead to a reduction in foodborne illnesses as well as reduced produce waste.

Combining essential oils and olive extract for control of multi-drug resistant Salmonella enterica on organic leafy greens

Science.gov (United States)

We investigated the combined antimicrobial effects of plant essential oils and olive extract against antibiotic resistant Salmonella enterica serovar Newport on organic leafy greens. Organic baby spinach, mature spinach, romaine lettuce, and iceberg lettuce were inoculated with S. Newport and dip-t...

The influence of the microbial quality of wastewater, lettuce cultivars and enumeration technique when estimating the microbial contamination of wastewater-irrigated lettuce.

Science.gov (United States)

Makkaew, P; Miller, M; Cromar, N J; Fallowfield, H J

2017-04-01

This study investigated the volume of wastewater retained on the surface of three different varieties of lettuce, Iceberg, Cos, and Oak leaf, following submersion in wastewater of different microbial qualities (10, 10 2 , 10 3 , and 10 4 E. coli MPN/100 mL) as a surrogate method for estimation of contamination of spray-irrigated lettuce. Uniquely, Escherichia coli was enumerated, after submersion, on both the outer and inner leaves and in a composite sample of lettuce. E. coli were enumerated using two techniques. Firstly, from samples of leaves - the direct method. Secondly, using an indirect method, where the E. coli concentrations were estimated from the volume of wastewater retained by the lettuce and the E. coli concentration of the wastewater. The results showed that different varieties of lettuce retained significantly different volumes of wastewater (p 0.01) were detected between E. coli counts obtained from different parts of lettuce, nor between the direct and indirect enumeration methods. Statistically significant linear relationships were derived relating the E. coli concentration of the wastewater in which the lettuces were submerged to the subsequent E. coli count on each variety the lettuce.

In vitro liberation of carotenoids from spinach and Asia Salads after different domestic kitchen procedures

DEFF Research Database (Denmark)

Eriksen, Jane Nygaard; Luu, Amy; Dragsted, Lars Ove

2016-01-01

-carotene liberation from spinach and Asia salads by applying an in vitro digestion protocol and UHPLC analysis. Reduction of particle size resulted in a three- to fourfold increase in liberation of lutein and β-carotene when comparing whole leaf and puree preparations of spinach. However, this positive effect...... was shown to be nullified by the severe heat impact during stir-frying of minced spinach, showing that domestic treatments need to be chosen carefully to maximise carotenoid liberation. Steaming significantly improved lutein liberation from Asia salads, but had no or a negative effect in spinach samples...

Differences in the deposition of radionuclides to leafy vegetables

International Nuclear Information System (INIS)

Tschiersch, J.; Shinonaga, T.; Heuberger, H.; Bunzl, K.; Pliml, A.; Dietl, F.; Keusch, M.

2003-01-01

To quantify the variability in deposition to several species, the dry deposition of gaseous elemental radio-iodine and particulate radio-caesium on mature leafy vegetables was studied inside a deposition chamber by comparative experiments. The simultaneous exposition of endive, head lettuce, red oak leaf lettuce, curly kale, white cabbage and spinach was performed under homogeneous and controlled conditions ( 131 vertical stroke 2 -portion, particle median, stomata opening, air humidity and temperature). Significant differences were observed for the 131 vertical stroke deposition on spring vegetables: the deposition on spinach was roughly 3times that on leaf lettuce, 4times that on endive and 9times that on head lettuce. For 134 Cs, there was no significant difference between spinach and leaf lettuce, about twice the amount was deposited on both species as on endive and 3times as on head lettuce. All summer vegetables showed differences in deposition. For Iodine, the deposition on spinach was roughly 3times (6times) that on curly kale and 35times (100times) that on white cabbage in the 2 experiments. For Caesium, the deposition to curly kale was highest, about twice that on spinach and 35times (80times) that on white cabbage. The deposition was always the lowest on the closed heads of white cabbage and head lettuce. The many open stomata of spinach increased the efficiency of gaseous deposition. In addition, rough and crimpy leafs increased the particle deposition efficiency. The estimation of the deposition velocity showed that dry deposition was in average about 8times higher for 131 vertical stroke than for 134 Cs. The influence of the particle size on the deposition velocity was small in the considered size range. Washing could reduce the contamination by about 10% for 131 vertical stroke and 45% for 134 Cs. (orig.) [de

Effect of Verticillium dahliae soil inoculum levels on spinach seed infection

DEFF Research Database (Denmark)

Sapkota, Rumakanta; Olesen, Merete Halkjær; Deleuran, Lise Christina

2016-01-01

Verticillium dahliae is a soilborne pathogen and a threat to spinach seed production. The aim of this study was to understand the relation between V. dahliae soil inoculum and infection in harvested seed. Quantitative polymerase chain reaction was used for quantification of the pathogen. Semifield...... experiments in which spinach was grown in soils with different inoculum levels enabled us to determine a threshold level for V. dahliae DNA of 0.003 ng/g of soil for seed infection to occur. Soils from production fields were sampled in 2013 and 2014 during and before planting, as well as the harvested seed....... Seed from plants grown in infested soils were infected with V. dahliae in samples from both the semifield and open-field experiments. Lower levels of pathogen were found in seed from spinach grown in soils with a scattered distribution of V. dahliae (one or two positive of three soil subsamples) than...

Lettuce contact allergy

DEFF Research Database (Denmark)

Paulsen, Evy; Andersen, Klaus E

2016-01-01

Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present...... person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy.......Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present...... new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22...

Monitoring of the vegetable garden open air spinach and soil radioactivity in Beijing during the Japan Fukushima nuclear accident

International Nuclear Information System (INIS)

Zhou Qiang; Xu Cuihua; Tuo Fei; Zhang Jing; Li Wenhong; Zhang Qing; Zhang Weijun; Zhang Jianfeng; Su Xu

2012-01-01

Objective: To detect artificial radionuclide content in the spinach and soil in open air vegetable garden in Beijing during Fukushima nuclear accident and to study the radioactive contamination characteristics of the samples. Methods: 6 spinach samples and 3 soil samples in open air vegetable garden were obtained through continuously sampling. High-purity germanium (HPGe) γ spectrometry was used to analyze activity concentrations of artificial radionuclide 131 I etc in these samples. Results: Artificial radionuclide 131 I was detected in the 6 open air spinach samples. Artificial radionuclide 137 Cs was detected in 3 vegetable garden soil samples, trace amount of 131 I was detected in 1 open-air surface soil sample alone. Conclusions: Following the Fukushima nuclear accident, spinach in Beijing's open-air vegetable garden was slightly polluted by artificial radionuclide 131 I, with the highest values of pollution appeared around April 4, 2011, but it could not cause harm to human health. (authors)

A comparative study of the antacid effect of raw spinach juice and spinach extract in an artificial stomach model.

Science.gov (United States)

Panda, Vandana Sanjeev; Shinde, Priyanka Mangesh

2016-12-01

BackgroundSpinacia oleracea known as spinach is a green-leafy vegetable consumed by people across the globe. It is reported to possess potent medicinal properties by virtue of its numerous antioxidant phytoconstituents, together termed as the natural antioxidant mixture (NAO). The present study compares the antacid effect of raw spinach juice with an antioxidant-rich methanolic extract of spinach (NAOE) in an artificial stomach model. MethodsThe pH of NAOE at various concentrations (50, 100 and 200 mg/mL) and its neutralizing effect on artificial gastric acid was determined and compared with that of raw spinach juice, water, the active control sodium bicarbonate (SB) and a marketed antacid preparation ENO. A modified model of Vatier's artificial stomach was used to determine the duration of consistent neutralization of artificial gastric acid for the test compounds. The neutralizing capacity of test compounds was determined in vitro using the classical titration method of Fordtran. Results NAOE (50, 100 and 200 mg/mL), spinach juice, SB and ENO showed significantly better acid-neutralizing effect, consistent duration of neutralization and higher antacid capacity when compared with water. Highest antacid activity was demonstrated by ENO and SB followed by spinach juice and NAOE200. Spinach juice exhibited an effect comparable to NAOE (200 mg/mL). ConclusionsThus, it may be concluded that spinach displays significant antacid activity be it in the raw juice form or as an extract in methanol.

Use of the Keele injector for sample introduction for gas chromatographic analysis of vinclozolin in lettuces.

Science.gov (United States)

Shim, J H; Lee, Y S; Kim, M R; Lee, C J; Kim, I S

2003-10-10

We examined a Keele injector for sample introduction for gas chromatographic analysis of vinclozolin treated in lettuces. Samples in milligram quantity were introduced into a glass tube in a Keele injector at a gas chromatograph injection port. The glass tube was then crushed to allow the sample to carry onto a capillary column in a normal manner. The standard calibration curve for quantitative detection of vinclozolin was obtained by determining vinclozolin spiked in samples at variable concentrations. The calibration curve showed a linear response to vinclozolin ranging from 0.05 to 1.0 microg/g, giving a slope value of 174.8, the y-intercept value of -2.8146 and the mean r2-value of 0.9994. Limit of quantification for vinclozolin was 0.05 microg/g by this method, comparable to 0.01 microg/g by a normal injector. When samples treated previously with vinclozolin were determined by the Keele injector, vinclozolin was found to be about 30% lower as compared to a normal method, suggesting about 70% recovery of the spiked vinclozolin by the Keele injector. From these results, the Keele injector was suggested to be potential for sample introduction in gas chromatographic analysis of vinclozolin in lettuce samples.

Lettuce contact allergy.

Science.gov (United States)

Paulsen, Evy; Andersen, Klaus E

2016-02-01

Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Lettuce breeding

Science.gov (United States)

In the 2016-2017 period, major efforts targeted resistance to lettuce drop caused by Sclerotinia species, Verticillium wilt, Fusarium wilt, bacterial leaf spot, corky root, downy mildew, drought tolerance, lettuce aphid, tipburn, shelf-life of salad-cut lettuce, and multiple disease resistance. Resi...

New poleroviruses associated with yellowing symptoms in different vegetable crops in Greece.

Science.gov (United States)

Lotos, L; Maliogka, V I; Katis, N I

2016-02-01

Four poleroviral isolates from Greece, two from lettuce, one from spinach and one from watermelon showing yellowing symptoms, were molecularly characterized by analyzing the sequence of a large part of the genome spanning from the 3'-terminal part of the RdRp to the end of the CP gene. The sequences were analyzed for their similarity and phylogenetic relationships to other members of the genus Polerovirus as well as for evidence of recombination events. The results revealed the existence of two putatively new viruses: one from lettuce and one from spinach, provisionally named "lettuce yellows virus" and "spinach yellows virus", respectively. Also, a new recombinant virus infecting lettuce, herein named "lettuce mild yellows virus", and a watermelon isolate of pepo aphid-borne yellows virus (PABYV) were identified. Our study highlights the existence of high genetic diversity within the genus Polerovirus, which could be associated with the emergence of new viral diseases in various crops worldwide.

Generic Escherichia coli contamination of spinach at the preharvest stage: effects of farm management and environmental factors.

Science.gov (United States)

Park, Sangshin; Navratil, Sarah; Gregory, Ashley; Bauer, Arin; Srinath, Indumathi; Jun, Mikyoung; Szonyi, Barbara; Nightingale, Kendra; Anciso, Juan; Ivanek, Renata

2013-07-01

The objective of this study was to determine the effects of farm management and environmental factors on preharvest spinach contamination with generic Escherichia coli as an indicator of fecal contamination. A repeated cross-sectional study was conducted by visiting spinach farms up to four times per growing season over a period of 2 years (2010 to 2011). Spinach samples (n = 955) were collected from 12 spinach farms in Colorado and Texas as representative states of the Western and Southwestern United States, respectively. During each farm visit, farmers were surveyed about farm-related management and environmental factors using a questionnaire. Associations between the prevalence of generic E. coli in spinach and farm-related factors were assessed by using a multivariable logistic regression model including random effects for farm and farm visit. Overall, 6.6% of spinach samples were positive for generic E. coli. Significant risk factors for spinach contamination with generic E. coli were the proximity (within 10 miles) of a poultry farm, the use of pond water for irrigation, a >66-day period since the planting of spinach, farming on fields previously used for grazing, the production of hay before spinach planting, and the farm location in the Southwestern United States. Contamination with generic E. coli was significantly reduced with an irrigation lapse time of >5 days as well as by several factors related to field workers, including the use of portable toilets, training to use portable toilets, and the use of hand-washing stations. To our knowledge, this is the first report of an association between field workers' personal hygiene and produce contamination with generic E. coli at the preharvest level. Collectively, our findings support that practice of good personal hygiene and other good farm management practices may reduce produce contamination with generic E. coli at the preharvest level.

Generic Escherichia coli Contamination of Spinach at the Preharvest Stage: Effects of Farm Management and Environmental Factors

Science.gov (United States)

Navratil, Sarah; Gregory, Ashley; Bauer, Arin; Srinath, Indumathi; Jun, Mikyoung; Szonyi, Barbara; Nightingale, Kendra; Anciso, Juan; Ivanek, Renata

2013-01-01

The objective of this study was to determine the effects of farm management and environmental factors on preharvest spinach contamination with generic Escherichia coli as an indicator of fecal contamination. A repeated cross-sectional study was conducted by visiting spinach farms up to four times per growing season over a period of 2 years (2010 to 2011). Spinach samples (n = 955) were collected from 12 spinach farms in Colorado and Texas as representative states of the Western and Southwestern United States, respectively. During each farm visit, farmers were surveyed about farm-related management and environmental factors using a questionnaire. Associations between the prevalence of generic E. coli in spinach and farm-related factors were assessed by using a multivariable logistic regression model including random effects for farm and farm visit. Overall, 6.6% of spinach samples were positive for generic E. coli. Significant risk factors for spinach contamination with generic E. coli were the proximity (within 10 miles) of a poultry farm, the use of pond water for irrigation, a >66-day period since the planting of spinach, farming on fields previously used for grazing, the production of hay before spinach planting, and the farm location in the Southwestern United States. Contamination with generic E. coli was significantly reduced with an irrigation lapse time of >5 days as well as by several factors related to field workers, including the use of portable toilets, training to use portable toilets, and the use of hand-washing stations. To our knowledge, this is the first report of an association between field workers' personal hygiene and produce contamination with generic E. coli at the preharvest level. Collectively, our findings support that practice of good personal hygiene and other good farm management practices may reduce produce contamination with generic E. coli at the preharvest level. PMID:23666336

Assessment of cobalt levels in wastewater, soil and vegetable ...

African Journals Online (AJOL)

carrot, lettuce, onion, spinach, cabbage, tomato and okra) samples collected on seasonal basis from January, 2013 to September 2014 along Kubanni stream channels in Zaria. The results show cobalt levels in wastewater were in the range of ...

Enzyme-assisted extraction of stabilized chlorophyll from spinach.

Science.gov (United States)

Özkan, Gülay; Ersus Bilek, Seda

2015-06-01

Zinc complex formation with chlorophyll derivatives in spinach pulp was studied by adding 300ppm Zn(2+) for production of stable food colorant, followed by the heating at 110°C for 15min. Zinc complex formation increased at pH values of 7.0 or greater. Pectinex Ultra SP-L was selected for enzyme-assisted release of zinc-chlorophyll derivatives from spinach pulp. Effect of enzyme concentration (1-9%), treatment temperature (30-60°C), and time (30-210min) on total chlorophyll content (TCC) were optimized using response surface methodology. A quadratic regression model (R(2)=0.9486) was obtained from the experimental design. Optimum treatment conditions were 8% enzyme concentration, 45°C, and 30min, which yielded a 50.747mgTCC/100g spinach pulp. Enzymatic treatment was followed by solvent extraction with ethanol at a solvent-to-sample ratio of 2.5:1 at 60°C for 45min for the highest TCC recovery. Pretreatment with enzyme and extraction in ethanol resulted in 39% increase in Zn-chlorophyll derivative yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

Detailed characterization of Mirafiori lettuce virus-resistant transgenic lettuce.

Science.gov (United States)

Kawazu, Yoichi; Fujiyama, Ryoi; Noguchi, Yuji; Kubota, Masaharu; Ito, Hidekazu; Fukuoka, Hiroyuki

2010-04-01

Lettuce big-vein disease is caused by Mirafiori lettuce virus (MiLV), which is vectored by the soil-borne fungus Olpidium brassicae. A MiLV-resistant transgenic lettuce line was developed through introducing inverted repeats of the MiLV coat protein (CP) gene. Here, a detailed characterization study of this lettuce line was conducted by comparing it with the parental, non-transformed 'Kaiser' cultivar. There were no significant differences between transgenic and non-transgenic lettuce in terms of pollen fertility, pollen dispersal, seed production, seed dispersal, dormancy, germination, growth of seedlings under low or high temperature, chromatographic patterns of leaf extracts, or effects of lettuce on the growth of broccoli or soil microflora. A significant difference in pollen size was noted, but the difference was small. The length of the cotyledons of the transgenic lettuce was shorter than that of 'Kaiser,' but there were no differences in other morphological characteristics. Agrobacterium tumefaciens used for the production of transgenic lettuce was not detected in transgenic seeds. The transgenic T(3), T(4), and T(5) generations showed higher resistance to MiLV and big-vein symptoms expression than the resistant 'Pacific' cultivar, indicating that high resistance to lettuce big-vein disease is stably inherited. PCR analysis showed that segregation of the CP gene was nearly 3:1 in the T(1) and T(2) generations, and that the transgenic T(3) generation was homozygous for the CP gene. Segregation of the neomycin phosphotransferase II (npt II) gene was about 3:1 in the T(1) generation, but the full length npt II gene was not detected in the T(2) or T(3) generation. The segregation pattern of the CP and npt II genes in the T(1) generation showed the expected 9:3:3:1 ratio. These results suggest that the fragment including the CP gene and that including the npt II gene have been integrated into two unlinked loci, and that the T(1) plant selected in our study did

Dry deposition of particulate Cs-134 to several leafy vegetable species and comparison to deposition of gaseous radioiodine

International Nuclear Information System (INIS)

Tschiersch, J.; Shinonaga, T.; Heuberger, H.

2004-01-01

The height of the dry deposition of particulate radionuclides to leafy vegetable is quite uncertain because of the different habit, surface texture and leaf uptake of the different species. There is no comparative data on the deposition to various species, but leafy vegetables are taken as reference plants for the estimation of the height of contamination of vegetable foods after a nuclear accident. Therefore new chamber experiments were performed to determine under homogeneous and controlled conditions the dry deposition of particulate radio-caesium on mature leafy vegetable. The simultaneous exposition of endive, head lettuce, red oak leaf lettuce and spinach (spring leafy vegetable) rsp. curly kale, white cabbage and spinach (summer leafy vegetable) was arranged. The sample collective of each species was such large that for the expected variation of the results a statistically firm analysis was possible. For spring vegetable, there was no significant difference observed in deposition of 134 Cs between spinach and leaf lettuce, about twice the amount was deposited on both species as on endive and 3 times as on head lettuce. All summer vegetables showed differences in deposition for Caesium, the deposition to curly kale was highest, about twice that on spinach and 35 times (80 times) that on white cabbage. The normalized deposition velocity could be estimated, in average it was about 8 times lower for 134 Cs than for gaseous elemental 131 I. The influence of the particle size on the deposition velocity was small in the considered size range of 0.58-1.1μm (AMAD) of the monodisperse aerosol. Washing could reduce the contamination by about 45% for 134 Cs. (author)

Comparative Infection Progress Analysis of Lettuce big-vein virus and Mirafiori lettuce virus in Lettuce Crops by Developed Molecular Diagnosis Techniques.

Science.gov (United States)

Navarro, Jose A; Botella, Francisco; Maruhenda, Antonio; Sastre, Pedro; Sánchez-Pina, M Amelia; Pallas, Vicente

2004-05-01

ABSTRACT Nonisotopic molecular dot blot hybridization technique and multiplex reverse transcription-polymerase chain reaction assay for the specific detection of Lettuce big-vein virus (LBVV) and Mirafiori lettuce virus (MiLV) in lettuce tissue were developed. Both procedures were suitable for the specific detection of both viruses in a range of naturally infected lettuce plants from various Spanish production areas and seven different cultivars. The study of the distribution of both viruses in the plant revealed that the highest concentration of LBVV and MiLV occurred in roots and old leaves, respectively. LBVV infection progress in a lettuce production area was faster than that observed for MiLV. In spite of different rates of virus infection progress, most lettuce plants became infected with both viruses about 100 days posttransplant. The appearance of both viruses in lettuce crops was preceded by a peak in the concentration of resting spores and zoosporangia of the fungus vector Olpidium brassicae in lettuce roots.

Effect of waste mica on transfer factors of {sup 134}Cs to spinach and lettuce; Effet de dechets de mica sur les facteurs de transfert du {sup 134}Cs a l'epinard et la laitue

Energy Technology Data Exchange (ETDEWEB)

Sreenivasa Chari, M.; Manjaiah, K.M. [Indian Agricultural Research Institute, Division of Soil Science and Agricultural Chemistry, New Delhi - 110012 (India); Sachdev, P.; Sachdev, M.S. [Indian Agricultural Research Institute, Nuclear Research Laboratory, New Delhi - 110012 (India)

2011-07-15

A greenhouse pot culture experiment was conducted to study the effect of graded levels of waste mica (0, 10, 20 and 40 g kg{sup -1}) on reducing the radiocesium uptake by spinach (Spinacia olerecea L) and lettuce (Lactuca sativa L.) grown in {sup 134}Cs-contaminated (at 37 k Bq kg{sup -1} soil) Inceptisols, Vertisols and Ultisols. The biomass yield, and potassium content and its uptake by crops have been significantly improved by waste mica application. The crops grown in Vertisols recorded higher biomass yield, and K content and its uptake as compared with Inceptisols and Ultisols. The average {sup 134}Cs transfer factor values recorded were: 0.21, 0.17 and 0.26 at the first cutting, 0.15, 0.12 and 0.28 at the second cutting and 0.07, 0.05 and 0.23 at the third cutting from Inceptisols, Vertisols and Ultisols, respectively. Waste mica significantly suppressed radiocesium uptake, the effect being more pronounced at 40 g mica kg{sup -1} soil. There exists an inverse relationship between the {sup 134}Cs transfer factors with plant potassium content and also the K uptake by the crops. (authors)

Uptake, translocation, and transformation of pentachlorophenol in soybean and spinach plants

International Nuclear Information System (INIS)

Casterline, J.L. Jr.; Barnett, N.M.; Ku, Y.

1985-01-01

Soybean plants were grown for 90 days and spinach plants for 64 days in a mixture of sterilized greenhouse soil and sand containing 10 ppm pentachlorophenol. All plant parts and soil samples were extracted and separated into nonpolar and polar fractions. Major nonpolar and polar metabolites were identified by gas-liquid chromatography and mass spectrometry. Nonpolar fractions from both soybean and spinach plants were found to contain pentachlorophenol and its metabolites, 2,3,4,6-tetrachlorophenol, methoxytetrachlorophenol, 2,3,4,6-tetrachloroanisole, and pentachloroanisole. Cleavage of polar metabolites from the soybean plants by acid hydrolysis yielded organic solvent-extractable products. These products were identified as pentachlorophenol, 2,3,4,6-tetrachlorophenol, and methoxytetrachlorophenol. Cleavage of polar materials from spinach plants yielded only pentachlorophenol. The polar metabolites from the soybean plants were also subjected to enzymatic cleavage by beta-glucosidase. The conjugates consisted mostly of O-glucosides of the same metabolites released by acid hydrolysis. Failure of hydrolysis by aryl sulfatase indicated that very little or no sulfates were present. The metabolites found in the plants were not detected in soil samples obtained from pots immediately after the plants were harvested

Irradiation of lettuce (Lactuca sativa. L.): microbiological and sensory aspects

International Nuclear Information System (INIS)

Tsuhako, Vanessa Provenzano

2005-01-01

The increasing demand for fresh foods have stimulated the marketing of minimally processed vegetables. However, these products maintain most of their natural microbiota even after being sanitized, including pathogenic microorganisms. Refrigerated storage allows the growth of psychotropic microorganisms and among them the pathogen Listeria monocytogenes. The ingestion of food contaminated with L. monocytogenes may represent a risk to pregnant women and their fetuses and to immunocompromised people. Non-thermal alternative processes for food preservation, such as irradiation, can reduce pathogenic and spoilage microorganism populations without impairing substantial changes in sensory, physical or chemical attributes. The aims of this research were to evaluate the effect of gamma radiation on L. monocytogenes artificially inoculated on minimally processed lettuce, to evaluate its effect on lettuce leaves through acceptance sensory test and to determine the irradiated vegetable shelf life through sensory and microbiological tests. A mixture of 4 types of lettuce (Iceberg, Boston, Loose-leaf and Red loose-leaf) were artificially inoculated with L. monocytogenes (7 log UFC/g lettuce) and then exposed to 0.3; 0.6; 0.9 and 1.2 kGy, under refrigeration. The DlO values for L. monocytogenes varied fram 0.18 to 0.21 kGy. Sensory and microbiological tests indicated that the shelf life of Iceberg lettuce stored at 7 deg C was 5 and 7 days for the irradiated and non-irradiated samples, respectively, and for the irradiated and non-irradiated Loose-leaf lettuce samples were 10 days. For the non-irradiated Boston sample, the shelf life was 3 days and for the Irradiated 7 days. Red loose-leaf showed 5 and 4 days of shelf lives for the irradiated and non-irradiated, respectively. Irradiated samples presented better microbiological quality than non-irradiated ones. The irradiation is feasible process to improve quality and safety of lettuce leaves. (author)

Development of a Standardized Approach for Assessing Potential Risks to Amphibians Exposed to Sediment and Hydric Soils

Science.gov (United States)

2004-05-01

different foods in amphibian tests. Possible foods considered for this study included boiled spinach, boiled lettuce , fish flakes, TetraMin...other foods such as boiled spinach or lettuce . • Sediment tests in flow-through chambers are preferable over static-renewal systems because of... hybridization may be possible. Amphibian Ecological Risk Assessment Guidance Manual Q:\\mw97\\Projects\\9070045\\419\\Appendix C\\appC-1

Antioxidant activity of fermented broccoli and spinach by Kombucha culture

Science.gov (United States)

Artanti, Nina; Susilowati, Agustine; Aspiyanto, Lotulung, Puspa Dewi Narrij; Maryati, Yati

2017-11-01

Broccoli (Brassica oleracea L.) and spinach (Amaranthus spp.) are vegetables that known to have many benefit for health. Previous studies on the fermentation of those vegetables using kombucha cultured showed increase in bioactive components such as total polyphenol content. The current studies was performed to evaluate the antioxidant activity of fermented spinach and broccoli before (feed) and after treatment with filtration (retentate and permeate). Filtration was conducted using Stirred Ultrafiltration Cell (SUFC) with UF membrane 100,000 MWCO mode at fixed condition (stirred rotation 300 rpm, room temperature, pressure 40 psia). Antioxidant evaluation was conducted using 2,2-diphenyl-1-picril hydrazyl (DPPH) free radical scavenging activity assay. The results showed that all samples from fermented broccoli showed antioxidant activity (feed 15.82% inhibition and retentate 15.29% inhibition), with the best antioxidant activity was obtained from permeate (75.98% inhibition). Whereas from fermented spinach only permeate showed antioxidant activity (21.84% inhibition) and it significantly lower than broccoli permeate. The mass spectrum of LCMS analysis on broccoli samples showed the present of several mass spectrum with (M+H) range from 148.1 to 442.5 in feed, retentate and permeate. In those samples (M+H) 360.4 always has the highest relative intensity. These results suggest that fermented broccoli has potential for development as functional drink for the source of antioxidant and the permeate obtained from filtration treatment significantly increased the antioxidant activity.

Agronomic viability of New Zealand spinach and kale intercropping.

Science.gov (United States)

Cecílio, Arthur B; Bianco, Matheus S; Tardivo, Caroline F; Pugina, Gabriel C M

2017-01-01

The intercropping is a production system that aims to provide increased yield with less environmental impact, due to greater efficiency in the use of natural resources and inputs involved in the production process. An experiment was carried out to evaluate the agronomic viability of kale and New Zealand spinach intercropping as a function of the spinach transplanting time. (0, 14, 28, 42, 56, 70, 84 and 98 days after transplanting of the kale). The total yield (TY) and yield per harvest (YH) of the kale in intercropping did not differ from those obtained in monoculture. The spinach TY was influenced by the transplanting time, the earlier the transplanting, the higher the TY. The spinach YH was not influenced by the transplanting time, but rather by the cultivation system. In intercropping, the spinach YH was 13.5% lower than in monoculture. The intercropping was agronomically feasible, since the land use efficiency index, which was not influenced by the transplanting time, had an average value of 1.71, indicating that the intercropping produced 71% more kale and spinach than the same area in monoculture. Competitiveness coefficient, aggressiveness and yield loss values showed that kale is the dominating species and spinach is the dominated.

Antioxidant properties of differently processed spinach products

NARCIS (Netherlands)

Castenmiller, J.J.M.; Linssen, J.P.H.; Heinonen, I.M.; Hopia, A.I.; Schwarz, K.; Hollman, P.C.H.; West, C.E.

2002-01-01

The effect of variously processed spinach products (whole-leaf, minced and enzymatically liquefied spinach) on lipid oxidation was determined. In an autoxidative methyl linoleate (MeLo) system the inhibition of hydroperoxide formation, measured by HPLC after three days of oxidation, was in

Agricultural Extension Needs of Spinach (Basella spp.) Farmers in ...

African Journals Online (AJOL)

USER

Spinach can be grown in a variety of fertile organic matter soil, and ... and takes an important place in the population diet because of its affordability and the nutrients it ..... fertilizer ( = 0.35), source for effectively marketing spinach ( = 0.34) and provision of credit for spinach .... of Fish Farming in Rivers State, Nigeria. Journal ...

Bacterial diversity and community structure in lettuce soil are shifted by cultivation time

Science.gov (United States)

Liu, Yiqian; Chang, Qing; Guo, Xu; Yi, Xinxin

2017-08-01

Compared with cereal production, vegetable production usually requires a greater degree of management and larger input of nutrients and irrigation, but these systems are not sustainable in the long term. This study aimed to what extent lettuce determine the bacterial community composition in the soil, during lettuce cultivation, pesticides and fertilizers were not apply to soil. Soil samples were collected from depths of 0-20cm and 20-40cm. A highthroughput sequencing approach was employed to investigate bacterial communities in lettuce-cultivated soil samples in a time-dependent manner. The dominant bacteria in the lettuce soil samples were mainly Proteobacteria, Actinobacteria, Chloroflexi, Nitrospirae, Firmicutes, Acidobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes, Gemmatimo nadetes, Cyanobacteria. Proteobacteria was the most abundant phylum in the 6 soil samples. The relative abundance of Acidobacteria, Firmicutes, Bacteroidetes, Verrucomicrobia and Cyanobacteria decreased through time of lettuce cultivation, but the relative abundance of Proteobacteria, Actinobacteria, Gemmatimonadetes, Chloroflexi, Planctomycetes and Nitrospirae increased over time. In the 0-20cm depth group and the 20-40cm depth soil, a similar pattern was observed that the percentage number of only shared OTUs between the early and late stage was lower than that between the early and middle stage soil, the result showed that lettuce growth can affect structure of soil bacterial communities.

Bacteriological quality of vegetables from organic and conventional production in different areas of Korea.

Science.gov (United States)

Tango, Charles Nkufi; Choi, Na-Jung; Chung, Myung-Sub; Oh, Deog Hwan

2014-08-01

Foods grown in organic production systems have been described as representing an increased risk to public health compared with foods from conventional production. Leafy vegetables (spinach, romaine lettuce, and green sesame leaves) grown in organic and conventional systems were collected from various areas in Korea and examined using standard culture methods to compare the microbiological quality of the produce grown in the two agricultural systems. The 354 samples of these leafy vegetables were analyzed for levels of indicator bacteria (aerobic bacteria, coliforms, and Escherichia coli) and the prevalence of the pathogens Staphylococcus aureus, E. coli O157:H7, Listeria monocytogenes, Bacillus cereus, and Salmonella. Aerobic bacteria and coliforms were detected in all vegetable types, but nonpathogenic E. coli was below the limit of detection in all samples. B. cereus was the most prevalent pathogen, found on 7 (11.1%) of the 63 organic spinach samples. The prevalence of S. aureus was highest in organic sesame leaves; it was found on 5 (8.0%) of the 63 samples. The prevalence of L. monocytogenes was highest on organic romaine lettuce and spinach; it was found in 4 (6.4%) of 63 samples of each type of vegetable. E. coli O157:H7 found on only 1 (1.58%) of 55 conventional spinach samples. These results suggest that farming type at most only slightly affects the hygienic quality of leafy vegetables, and no effect was found for sample collection area. Salmonella was not isolated from any of the conventional or organic leafy vegetables. These results do not support the hypothesis that organic produce poses a substantially greater risk of pathogen contamination than does conventional produce.

Faecal and protozoan parasite contamination of water spinach (Ipomoea aquatica) cultivated in urban wastewater in Phnom Penh, Cambodia

DEFF Research Database (Denmark)

Anh, Vuong Tuan; Tram, Nguyen Thuy; Klank, Lise Tønner

2007-01-01

Objective To identify the level of contamination with thermotolerant coliforms (ThC), intestinal helminth eggs and protozoan parasites in water spinach (Ipomoea aquatica) cultivated in a wastewater-fed lake in Phnom Penh, Cambodia. Methods The investigation was carried out from July 2004 to May...... into a stream. Water spinach samples were harvested at each of the three locations with and without wastewater contact according to the normal practices of farmers, and analysed for ThC, protozoan parasites (Giardia, Cryptosporidium and Cyclospora), and helminth eggs (Ascaris lumbricoides, Trichuris trichura...... and hookworm) using standard methods. Wastewater samples were also collected at each of the three locations and analysed for ThC and helminth eggs. Results High concentrations of ThC (approximately 10(5)-10(7)/g) were found in water spinach samples. ThC mean counts did not differ significantly, neither between...

JPRS Report Environmental Issues

Science.gov (United States)

1990-08-31

grow their own lettuce , spinach, strawberry and cherries. Now people are asking: How long have they and their children been eating produce containing...contamina- tion to be as severe as it turned out. Plant tests were performed in seven locations, involving spinach, lettuce and sorrels. The...no sturgeon. Then they thought quickly, and released some kind of fish with a funny name, bester or something (a hybrid of beluga and sterlet). But

Isolation of chlorophyll a from spinach leaves

Directory of Open Access Journals (Sweden)

E.D. Dikio

2008-08-01

Full Text Available An efficient method for separating chlorophyll a from spinach leaves by column chromatography and solvent extraction techniques has been developed. The purity and identity of the chlorophyll a have been confirmed by UV-Vis, IR and mass spectrometry. Yields from 100 g of freeze-dried spinach were 23 – 24 mg of chlorophyll a.

Development of marker-free transgenic lettuce resistant to Mirafiori lettuce big-vein virus.

Science.gov (United States)

Kawazu, Yoichi; Fujiyama, Ryoi; Imanishi, Shunsuke; Fukuoka, Hiroyuki; Yamaguchi, Hirotaka; Matsumoto, Satoru

2016-10-01

Lettuce big-vein disease caused by Mirafiori lettuce big-vein virus (MLBVV) is found in major lettuce production areas worldwide, but highly resistant cultivars have not yet been developed. To produce MLBVV-resistant marker-free transgenic lettuce that would have a transgene with a promoter and terminator of lettuce origin, we constructed a two T-DNA binary vector, in which the first T-DNA contained the selectable marker gene neomycin phosphotransferase II, and the second T-DNA contained the lettuce ubiquitin gene promoter and terminator and inverted repeats of the coat protein (CP) gene of MLBVV. This vector was introduced into lettuce cultivars 'Watson' and 'Fuyuhikari' by Agrobacterium tumefaciens-mediated transformation. Regenerated plants (T0 generation) that were CP gene-positive by PCR analysis were self-pollinated, and 312 T1 lines were analyzed for resistance to MLBVV. Virus-negative plants were checked for the CP gene and the marker gene, and nine lines were obtained which were marker-free and resistant to MLBVV. Southern blot analysis showed that three of the nine lines had two copies of the CP gene, whereas six lines had a single copy and were used for further analysis. Small interfering RNAs, which are indicative of RNA silencing, were detected in all six lines. MLBVV infection was inhibited in all six lines in resistance tests performed in a growth chamber and a greenhouse, resulting in a high degree of resistance to lettuce big-vein disease. Transgenic lettuce lines produced in this study could be used as resistant cultivars or parental lines for breeding.

Phloem sap collection from lettuce (Lactuca sativa L.): Methodology and yield.

Science.gov (United States)

van Helden, M; Tjallingii, W F; van Beek, T A

1994-12-01

Three methods to collect phloem sap on different lettuce lines were optimized and are described in detail. The success ratio for stylectomy of aphids was over 80% through the combination of a specially designed setup and electrical penetration graphs to monitor phloem sap ingestion. For unknown reasons on some lettuce lines stylets never showed sustained exudation. There were clear differences in stylet exudation between two aphid species on the same lettuce line. Honeydew collection in hexadecane made accurate quantitative analysis possible; samples were large and clean, but biotransformed. The EDTA chelation method produced large samples, but dilution, oxidation, and impurities from the wound surface reduced the reliability.

Plants: Partners in Health? Vegetables, Fruits, Herbs, and You

Science.gov (United States)

... and types every day. Broccoli, spinach, collard greens, kale, and other dark leafy greens are good choices. ... opposite effect. Foods rich in vitamin K include kale, spinach, Brussels sprouts, and some types of lettuce. ...

Reducing microbial contamination on wastewater-irrigated lettuce by cessation of irrigation before harvesting

DEFF Research Database (Denmark)

Keraita, Bernard; Konradsen, Flemming; Drechsel, Pay

2007-01-01

OBJECTIVE: To assess the effectiveness of cessation of irrigation before harvesting in reducing microbial contamination of lettuce irrigated with wastewater in urban vegetable farming in Ghana. METHODS: Assessment was done under actual field conditions with urban vegetable farmers in Ghana. Trials...... were arranged in completely randomized block design and done both in the dry and wet seasons. Seven hundred and twenty-six lettuce samples and 36 water samples were analysed for thermotolerant coliforms and helminth eggs. RESULTS: On average, 0.65 log units for indicator thermotolerant coliforms and 0.......4 helminth eggs per 100 g of lettuce were removed on each non-irrigated day from lettuce in the dry season. This corresponded to a daily loss of 1.4 tonnes/ha of fresh weight of lettuce. As an input for exposure analysis to make risk estimates, the decay coefficient, k, for thermotolerant coliforms was 0...

Cellular transport of lutein is greater from uncooked rather than cooked spinach irrespective of whether it is fresh, frozen, or canned.

Science.gov (United States)

O'Sullivan, Laurie; Ryan, Lisa; Aherne, S Aisling; O'Brien, Nora M

2008-08-01

Lutein, a carotenoid found in significant levels in spinach, has attracted a great deal of attention owing to its reported function as a shield against the photooxidative effects of blue light. Therefore, the rationale of this study was to examine the effects of various processing and cooking methods on lutein bioavailability from spinach (Spinacia oleracea) using an in vitro digestion procedure coupled with the use of a human intestinal Caco-2 cell model. Fresh, frozen, and canned spinach were analyzed uncooked and after boiling or microwave cooking. Lutein content from the uncooked and cooked digested food (digestate) and appropriate micelles was determined. Micellarized lutein from the spinach samples was adjusted to 0.1 micromol/L and added to Caco-2 cells. Cellular uptake and secretion (cellular transport) of lutein were determined. Our results showed that digestate obtained from uncooked canned spinach had greater lutein content (P canned spinach digestate and micelles compared with their uncooked counterparts. Interestingly, there were no differences in the micellarization of lutein between the cooking and processing methods. Cellular transport of lutein was greater from uncooked spinach micelles compared with boiled or microwave-cooked spinach. To conclude, although the lutein content of digesta and micelles may have been modified, its micellarization was not significantly affected by any of the cooking or processing methods tested. In general, cellular transport of lutein was greatest in uncooked spinach irrespective of whether the spinach was fresh, frozen, or canned.

Concentration of cadmium, zinc and manganese in root, stalk and leaf of spinach and tomato in Hamedan

Directory of Open Access Journals (Sweden)

A. Ghobadi

2016-11-01

Full Text Available Heavy metals are considers as significant environment pollutants. Their entrance into food chain is a serious health hazard to humans. This study was conducted to determine the concentrations of Cadmium, Zinc and Manganese in root, stalk and leaf portions of spinach and tomato. For this reason, during 2014 in Hamedan city, 3 farms with 5 repetitions from each farm were sampled. Samples were subjected to acid-digestion and the concentrations of the elements were assayed by inductively coupled plasma (ICP. According to the results, the average concentrations of heavy metals in root, stalk and leaf of spinach was estimated at: cadmium, 0.14, 0.24, 0.34 mg/kg, zinc, 15.53, 24.82, 35 mg/kg and manganese, 26.59, 24.42, 45.38 mg/kg, respectively. The data for the tomato samples were: cadmium, 16.20, 24.42, 33.81 mg/kg, Zinc, 21.48, 39.74, 52.92 mg/kg and manganese, 26.60, 42.41, 61.90 mg/kg, respectively. The mean concentration of cadmium and manganese in spinach and tomato showed a significant difference with the WHO/FAO standard limit. However, in the case of zinc the difference was insignificant. It was concluded that in this experiment the spinach and tomato samples were polluted with higher concentration of cadmium and manganese than the approved limit of WHO/FAO and therefore was found risky for the consumers.

Series of Norovirus Outbreaks Caused by Consumption of Green Coral Lettuce, Denmark, April 2016

DEFF Research Database (Denmark)

Müller, Luise; Rasmussen, Lasse Dam; Jensen, Tenna

2016-01-01

In early April 2016, an unusual high number of point-source outbreaks of gastrointestinal disease were reported to occur in Denmark. Outbreaks were individually investigated. Two analytical studies were performed. Patient stool samples collected and analysed; positive stool samples were sequenced...... over the polymerase and/or capsid gene areas. Implicated lettuce heads were collected and analysed for the presence of norovirus. Foods were traced-back and traced-forward and international alert systems applied. A total of 23 linked point-source outbreaks occurred over the course of one week. Fresh...... green coral lettuce (Lollo Bionda lettuce) had been consumed in all settings. In a cohort study including 234 participants a dish containing green lettuce was associated with illness. Norovirus of Genogroup I (GI) was detected in samples from 28 patients comprising eight of the outbreaks. Sequencing...

Persistence of 14C maneb in lettuce plants an soil

International Nuclear Information System (INIS)

Bennaceur, M.; Sennaoui, Z.; Meguenni, H.

1992-10-01

Maneb residue is studied on lettuce plant and soil after spraying on greenhouse with 14C maneb. The residues declined with time. After 37 days from the application, 14C maneb residues in water extracts declined to 1,5. 10-2ug/g from 5,8. 10-1ug/g of the zero day sample in lettuce plants and 4,6. 10-3ug/g from 1,73. 10-1ug/g in soil. The 14C internals residues in lettuce and soil increase respectively till 16 days and 24 days, then decrease to 88% and 4,05% after 37 days. ETU was present in lettuce plant after 8 days then decreases with time. Two metabolites were identified by TLC (EU,ETU)

Determination of Profenofos Pesticidal Residue in Lettuce (Lactuca sativa L. by Gas Chromatographic Method

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Yohannes Alen

2015-05-01

Full Text Available The determination of profenofos pesticidal residue in the lettuce (Lactuca sativa L. by using gas chromatography using flame photometric detector (FPD had been investigated. The lettuce was collected from Padang Luar area, Agam distric, West Sumatera. Sample for determination of profenofos residue divided into three groups: unwashed (A, washed with water (B, and washed with detergent (C. Maceration with sonication was used for the extraction using ethylacetateas a solvent. The results showed that profenofos pesticide residue in sample A, B and C were 0.204, 0.080 and 0.061 ppm, respectively. These profenofos pesticidal residue are over than the Maximum Residue Limits (MRL that established by The Japan Food Chemical Research Foundation (0.05 ppm even though World Health Organization (WHO has not established Maximum Residue Limits (MRL profenofos on lettuce. Based on the statistical analysis one-way method (Anova using SPSS 20.0 showed that there was a significant concentrations difference between lettuce A from lettuce B and lettuce C with p < 0.05.

Resistance to lettuce aphid (Nasonovia ribisnigri) biotype 0 in wild lettuce accessions PI 491093 and PI 274378

Science.gov (United States)

Lettuce aphid, Nasonovia ribisnigri Mosley (Homoptera : Aphididae), is a major insect pest of lettuce, Lactuca sativa L, in many commercial lettuce productions areas around the world. Resistance to lettuce aphid was first reported in Lactuca virosa L. accession IVT 280 and characterized as complete,...

Microbiological quality and safety assessment of lettuce production in Brazil.

Science.gov (United States)

Ceuppens, Siele; Hessel, Claudia Titze; de Quadros Rodrigues, Rochele; Bartz, Sabrina; Tondo, Eduardo César; Uyttendaele, Mieke

2014-07-02

The microbiological quality and safety of lettuce during primary production in Brazil were determined by enumeration of hygiene indicators Escherichia coli, coliforms and enterococci and detection of enteric pathogens Salmonella and E. coli O157:H7 in organic fertilizers, soil, irrigation water, lettuce crops, harvest boxes and worker's hands taken from six different lettuce farms throughout the crop growth cycle. Generic E. coli was a suitable indicator for the presence of Salmonella and E. coli O157:H7, while coliforms and enterococci were not. Few pathogens were detected: 5 salmonellae and 2 E. coli O157:H7 from 260 samples, of which only one was lettuce and the others were manure, soil and water. Most (5/7) pathogens were isolated from the same farm and all were from organic production. Statistical analysis revealed the following environmental and agro-technical risk factors for increased microbial load and pathogen prevalence in lettuce production: high temperature, flooding of lettuce fields, application of contaminated organic fertilizer, irrigation with water of inferior quality and large distances between the field and toilets. Control of the composting process of organic fertilizers and the irrigation water quality appear most crucial to improve and/or maintain the microbiological quality and safety during the primary production of lettuce. Copyright © 2014 Elsevier B.V. All rights reserved.

Using a Specific RNA-Protein Interaction To Quench the Fluorescent RNA Spinach.

Science.gov (United States)

Roszyk, Laura; Kollenda, Sebastian; Hennig, Sven

2017-12-15

RNAs are involved in interaction networks with other biomolecules and are crucial for proper cell function. Yet their biochemical analysis remains challenging. For Förster Resonance Energy Transfer (FRET), a common tool to study such interaction networks, two interacting molecules have to be fluorescently labeled. "Spinach" is a genetically encodable RNA aptamer that starts to fluoresce upon binding of an organic molecule. Therefore, it is a biological fluorophore tag for RNAs. However, spinach has never been used in a FRET assembly before. Here, we describe how spinach is quenched when close to acceptors. We used RNA-DNA hybridization to bring quenchers or red organic dyes in close proximity to spinach. Furthermore, we investigate RNA-protein interactions quantitatively on the example of Pseudomonas aeruginosa phage coat protein 7 (PP7) and its interacting pp7-RNA. We utilize spinach quenching as a fully genetically encodable system even under lysate conditions. Therefore, this work represents a direct method to analyze RNA-protein interactions by quenching the spinach aptamer.

Uptake and Accumulation of Pharmaceuticals in Lettuce Under Surface and Overhead Irrigations

Science.gov (United States)

Bhalsod, G.; Chuang, Y. H.; Jeon, S.; Gui, W.; Li, H.; Guber, A.; Zhang, W.

2015-12-01

Pharmaceuticals and personal care products are being widely detected in wastewater and surface waters. As fresh water becomes scarcer, interests in using reclaimed water for crop irrigation is intensified. Since reclaimed waters often carry trace levels of pharmaceuticals, accumulation of pharmaceuticals in food crops could increase the risk of human exposure. This study aims to investigate uptake and accumulations of pharmaceuticals in greenhouse-grown lettuce under contrasting irrigation practices (i.e., overhead and surface irrigations). Lettuce was irrigated with water spiked with 11 commonly used pharmaceuticals (acetaminophen, caffeine, carbamazepine, sulfadiazine, sulfamethoxazole, carbadox, trimethoprim, lincomycin hydrochloride, oxytetracycline hydrochloride, monensin sodium, and tylosin). Weekly sampling of lettuce roots, shoots, and soils were continued for 5 weeks, and the samples were freeze dried, extracted for pharmaceuticals and analyzed by LC-MS/MS. Preliminary results indicate that higher concentrations of pharmaceuticals were found in overhead irrigated lettuce compared to surface irrigated lettuce. For carbamezapine, sulfadiazine, trimethoprim, oxytetracycline, and monensin sodium, their concentrations generally increased in lettuce shoots in the overhead treatment over time. However, acetaminophen was found at higher concentrations in both shoots and roots, indicating that acetaminophen can be easily transported in the plant system. This study provides insight on developing better strategies for using reclaimed water for crop irrigations, while minimizing the potential risks of pharmaceutical contamination of vegetables.

CONSUMER ATTITUDES TOWARD ORGANICALLY GROWN LETTUCE

OpenAIRE

Wolf, Marianne McGarry; Johnson, Bradey; Cochran, Kerry; Hamilton, Lynn L.

2002-01-01

This research shows that approximately 29 percent of lettuce purchases in California expect to purchase an organically grown lettuce product in the future. Organic lettuce purchasers are more likely to be female, have a higher household income and a higher level of education. Consumers are concerned with the freshness, quality, price, and environmental impact of the lettuce they purchase.

Decontamination and survival of Enterobacteriaceae on shredded iceberg lettuce during storage.

Science.gov (United States)

Osaili, Tareq M; Alaboudi, Akram R; Al-Quran, Heba N; Al-Nabulsi, Anas A

2018-08-01

Enterobacteriaceae family can contaminate fresh produce at any stage of production either at pre-harvest or post-harvest stages. The objectives of the current study were to i) identify Enterobacteriaceae species on iceberg lettuce, ii) compare the decontamination efficiency of water, sodium hypochlorite (free chlorine 200 ppm), peroxyacetic acid (PA 80 ppm; Kenocid 2100 ® ) or their combinations and ionizing radiation against Enterobacteriaceae on shredded iceberg lettuce and iii) determine the survival of Enterobacteriaceae post-treatment storage of shredded iceberg lettuce at 4, 10 and 25 °C, for up to 7 days. Klebsiella pneumonia spp. pneumonia, Enterobacter cloacae, Klebsiella oxytoca, Pantoea spp., Leclercia adecarboxylata and Kluyvera ascorbate were identified on iceberg lettuce. No significant difference (P≥ 0.05) among Enterobacteriaceae survival after washing with water or sanitizing with sodium hypochlorite or Kenocid 2100 ® (reduction ≤ 0.6 log CFU/g) were found. Combined sanitizer treatments were more effective against Enterobacteriaceae than single washing/sanitizing treatments. Sanitization of iceberg lettuce with combined washing/sanitizing treatments reduced Enterobacteriaceae by 0.85-2.24 CFU/g. Post-treatment growth of Enterobacteriaceae during storage on samples sanitized with sodium hypochlorite and Kenocid 2100 ® was more than on samples washed with water. The D 10 -value of Enterobacteriaceae on shredded iceberg lettuce was 0.21 KGy. The reduction of Enterobacteriaceae populations on iceberg after gamma radiation (0.6 KGy) was 3 log CFU/g, however, Enterobacteriaceae counts increased post-irradiation storage by 4-5 log CFU/g. Therefore, washing shredded iceberg lettuce with combined sanitizing treatment (sodium hypochlorite/sodium hypochlorite, sodium hypochlorite/Kenocid 2100 ® , or Kenocid 2100 ® /Kenocid 2100 ® ) for total time of 6 min or exposing it to gamma irradiation (0.6 KGy) can decrease the risk of

Enhancement of iron content in spinach plants stimulated by magnetic nano particles

Energy Technology Data Exchange (ETDEWEB)

Yulianto, Agus; Astuti, Budi; Amalia, Saptaria Rosa [Physics Department, Faculty of Mathematics and Natural Science, Universitas Negeri Semarang (Indonesia)

2016-04-19

In our previous study, the iron content in spinach plants could be detected by magnetic susceptibility values. In the present work, magnetic nano particles were found from the iron sand. The magnetic nano particles are synthesis by using co-precipitation process and sol-gel technique. The stimulation of magnetic nano particles in the plant has been done by the provision of magnetic nano particles in growing media. After certain time, plant samples was characterized using susceptibility-meter MS2B and atomic absorption spectroscopy to measure the magnetic susceptibility and the amount of iron content that absorbed of the plant, respectively. The iron content in the spinach plants was increased when the magnetic nano particles was injected in the growing media.

Nitrate accumulation in spinach

NARCIS (Netherlands)

Steingröver, Eveliene Geertruda

1986-01-01

Leafy vegetables, like spinach, may contain high concentrations of nitrate. In the Netherlands, about 75% of mean daily intake of nitrate orginates from the consumption of vegatables. Hazards to human health are associated with the reduction of nitrate to nitrite. Acute nitrite poisoning causes

Assessment of microbiological contamination of fresh, minimally processed, and ready-to-eat lettuces (Lactuca sativa), Rio de Janeiro State, Brazil.

Science.gov (United States)

Brandão, Marcelo L L; Almeida, Davi O; Bispo, Fernanda C P; Bricio, Silvia M L; Marin, Victor A; Miagostovich, Marize P

2014-05-01

This study aimed to assess the microbiological contamination of lettuces commercialized in Rio de Janeiro, Brazil, in order to investigate detection of norovirus genogroup II (NoV GII), Salmonella spp., total and fecal coliforms, such as Escherichia coli. For NoV detection samples were processed using the adsorption-elution concentration method associated to real-time quantitative polymerase chain reaction (qPCR). A total of 90 samples of lettuce including 30 whole fresh lettuces, 30 minimally processed (MP) lettuces, and 30 raw ready-to-eat (RTE) lettuce salads were randomly collected from different supermarkets (fresh and MP lettuce samples), food services, and self-service restaurants (RTE lettuce salads), all located in Rio de Janeiro, Brazil, from October 2010 to December 2011. NoV GII was not detected and PP7 bacteriophage used as internal control process (ICP) was recovered in 40.0%, 86.7%, and 76.7% of those samples, respectively. Salmonella spp. was not detected although fecal contamination has been observed by fecal coliform concentrations higher than 10(2) most probable number/g. E. coli was detected in 70.0%, 6.7%, and 30.0% of fresh, MP, and RTE samples, respectively. This study highlights the need to improve hygiene procedures at all stages of vegetable production and to show PP7 bacteriophage as an ICP for recovering RNA viruses' methods from MP and RTE lettuce samples, encouraging the evaluation of new protocols that facilitate the establishment of methodologies for NoV detection in a greater number of food microbiology laboratories. The PP7 bacteriophage can be used as an internal control process in methods for recovering RNA viruses from minimally processed and ready-to-eat lettuce samples. © 2014 Institute of Food Technologists®

Lutein bioavailability is higher from lutein-enriched eggs than from supplements and spinach in men.

Science.gov (United States)

Chung, Hae-Yun; Rasmussen, Helen M; Johnson, Elizabeth J

2004-08-01

Lutein may be protective against diseases such as age-related macular degeneration (ARMD). At present, data regarding bioavailability of lutein from various sources are insufficient. Healthy men (n = 10) participated in an intervention study with a crossover design. After a 2-wk washout period during which they consumed a low-carotenoid diet, the men were administered 1 of 4 lutein doses (lutein supplement, lutein ester supplement, spinach, and lutein-enriched egg) for 9 d. All lutein doses provided 6 mg lutein except for the lutein ester dose, which provided 5.5 mg lutein equivalents. Serum samples were collected from fasting subjects on d -14, 1 (baseline), 2, 3, and 10 and analyzed for changes in lutein concentration. Triacylglycerol-rich lipoproteins (TRL) were separated from postprandial blood samples (0-24 h) after the first lutein dose and analyzed for lutein concentration. Subjects completed all 4 treatments of the study in random order. Results from repeated-measures 1-way ANOVA showed that the baseline and dose-adjusted lutein response in serum was significantly higher after egg consumption than after lutein, lutein ester, and spinach consumption on d 10. There was no significant difference in TRL response. In conclusion, the lutein bioavailability from egg is higher than that from other sources such as lutein, lutein ester supplements, and spinach. The lutein bioavailability from lutein, lutein ester supplements, and spinach did not differ. This finding may have implications for dietary recommendations that may decrease the risk of certain diseases, e.g., ARMD.

Potential internalisation of caliciviruses in lettuce.

Science.gov (United States)

Urbanucci, A; Myrmel, M; Berg, I; von Bonsdorff, C-H; Maunula, L

2009-10-31

Fresh produce such as lettuce (Lactuca sativa) has often been linked to epidemic viral gastroenteritis. In these cases, it is unknown whether the viral contamination has occurred during the growing or the processing of the implicated product. In this study lettuce was grown in the presence of enteric viruses, and the uptake of viruses via the roots into the edible parts (leaves and stem) of the lettuce plants was investigated, for plants with both intact and damaged roots. The roots of lettuce, growing either in hydroponic culture or in soil, were exposed to canine calicivirus (CaCV) and a human genogroup 2 norovirus (HuNoV) by these being added into the water or soil in which the lettuce was growing. Leaves from lettuce plants and seedlings were examined for viruses by real-time RT-PCR. When the lettuce plants were exposed to very high concentrations of CaCV, the virus was detected in lettuce leaves, indicating contamination via the roots, but the frequency of positive results was low. Internalisation occurred in both seedlings and grown plants, in both hydroponic and soil cultures, and occurred whether the roots were intact or damaged. However, internalisation of HuNoV was not detected in any of the experimental set ups, although the concentrations to which the plants were exposed were relatively high. Based on these results, viral contamination of lettuce plants via roots cannot be excluded, but is apparently not an important transmission route for viruses.

Microbial risk in wastewater irrigated lettuce: comparing Escherichia coli contamination from an experimental site with a laboratory approach.

Science.gov (United States)

Makkaew, P; Miller, M; Fallowfield, H J; Cromar, N J

This study assessed the contamination of Escherichia coli, in lettuce grown with treated domestic wastewater in four different irrigation configurations: open spray, spray under plastic sheet cover, open drip and drip under plastic sheet cover. Samples of lettuce from each irrigation configuration and irrigating wastewater were collected during the growing season. No E. coli was detected in lettuce from drip irrigated beds. All lettuce samples from spray beds were positive for E. coli, however, no statistical difference (p > 0.05) was detected between lettuces grown in open spray or covered spray beds. The results from the field experiment were also compared to a laboratory experiment which used submersion of lettuce in wastewater of known E. coli concentration as a surrogate method to assess contamination following irrigation. The microbial quality of spray bed lettuces was not significantly different from submersed lettuce when irrigated with wastewater containing 1,299.7 E. coli MPN/100 mL (p > 0.05). This study is significant since it is the first to validate that the microbial contamination of lettuce irrigated with wastewater in the field is comparable with a laboratory technique frequently applied in the quantitative microbial risk assessment of the consumption of wastewater irrigated salad crops.

Perception of bitterness, sweetness and liking of different genotypes of lettuce.

Science.gov (United States)

Chadwick, M; Gawthrop, F; Michelmore, R W; Wagstaff, C; Methven, L

2016-04-15

Lettuce is an important leafy vegetable, consumed across the world, containing bitter sesquiterpenoid lactone (SL) compounds that may negatively affect consumer acceptance and consumption. We assessed liking of samples with differing absolute abundance and different ratios of bitter:sweet compounds by analysing recombinant inbred lines (RILs) from an interspecific lettuce mapping population derived from a cross between a wild (L. serriola acc. UC96US23) and domesticated lettuce (L. sativa, cv. Salinas). We found that the ratio of bitter:sweet compounds was a key determinant of bitterness perception and liking. We were able to demonstrate that SLs, such as 8-deoxylactucin-15-sulphate, contribute most strongly to bitterness perception, whilst 15-p-hydroxylphenylacetyllactucin-8-sulphate does not contribute to bitter taste. Glucose was the sugar most highly correlated with sweetness perception. There is a genetic basis to the biochemical composition of lettuce. This information will be useful in lettuce breeding programmes in order to produce leaves with more favourable taste profiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Fermented Spinach as Sources of Pre-Converted Nitrite on Color Development of Cured Pork Loin

Science.gov (United States)

Hwang, Ko-Eun

2017-01-01

The effect of fermented spinach extracts on color development in cured meats was investigated in this study. The pH values of raw cured meats without addition of fermented spinach extract or nitrite (negative control) were higher (pmeats in treatment groups were decreased with increasing addition levels of fermented spinach extract. The lightness and yellowness values of raw cured meats formulated with fermented spinach extract were higher (pmeats were increased with increasing fermented spinach extract levels, whereas the yellowness values of cooked cured meats were decreased with increasing levels of fermented spinach extract. The lowest volatile basic nitrogen (VBN) and thiobarbituric acid reactive substances (TBARS) values were observed in the positive control group with addition of nitrite. TBARS values of cured meats added with fermented spinach extract were decreased with increasing levels of fermented spinach extract and VBN values of curing meat with 30% fermented spinach extract was lower than the other treatments. Total viable bacterial counts in cured meats added with fermented spinach extract ranged from 0.34-1.01 Log CFU/g. E. coli and coliform bacteria were not observed in any of the cured meats treated with fermented spinach extracts or nitrite. Residual nitrite contents in treatment groups were increased with increasing levels of fermented spinach extract added. These results demonstrated that fermented spinach could be added to meat products to improve own curing characteristics. PMID:28316477

Investigation Of Infrared Drying Behaviour Of Spinach Leaves Using ANN Methodology And Dried Product Quality

Directory of Open Access Journals (Sweden)

Sarimeseli Ayse

2015-12-01

Full Text Available Effects of infrared power output and sample mass on drying behaviour, colour parameters, ascorbic acid degradation, rehydration characteristics and some sensory scores of spinach leaves were investigated. Within both of the range of the infrared power outputs, 300–500 W, and sample amounts, 15–60 g, moisture content of the leaves was reduced from 6.0 to 0.1±(0.01 kg water/kg dry base value. It was recorded that drying times of the spinach leaves varied between 3.5–10 min for constant sample amount, and 4–16.5 min for constant power output. Experimental drying data obtained were successfully investigated by using artificial neural network methodology. Some changes were recorded in the quality parameters of the dried leaves, and acceptable sensory scores for the dried leaves were observed in all of the experimental conditions.

SPECIFICITY OF ACCUMULATION OF VARIOUS RADIONUCLIDES (137Cs и 90Sr IN SPINACH (Spinacia oleracea L.

Directory of Open Access Journals (Sweden)

A. V. Soldatenko

2016-01-01

Full Text Available Knowledge of the specificity of accumulation of 137Cs and 90Sr by plants and limits of accumulation by plant fruits plays a key role at breeding of vegetable crops, which make demand for ecological safety of the product. The article is concerned with the study of varietal sources of spinach (Spinacia oleracea L. aimed at development of ecological safety product on the territory polluted by radionuclides.The specificity of accumulation of radionuclides 137Cs and 90Sr was studied in 54 varieties of spinach at industrial contaminated and polluted lands. Experimental tests were conducted in the Moscow and Bryansk regions in 2012 and 2014. The absolute value of radionuclide 90Sr was higher than absolute value of radionuclide 137Cs in all studied zones. It was found that the hazard rate of 90Sr is higher because the level of pollution of product reaches up to 76% from maximum permissible concentration (MPC, while the level of product pollution by 137Cs is 26,4% from MPC. The spinach genotype differentiation for 90Sr in the most environments is lower than differentiation for 137Cs. The histograms of distribution 90Sr and 137Cs showed that samples amount in the groups of accumulation for both radionuclides are equal. Statistically significant data for radionuclides 137Cs and 90Sr in spinach were not obtained. The evaluation of spinach for low content of radionuclides should be conducted separately for each radionuclide on various backgrounds.

Monitoring programme on nitrates in vegetables and vegetable-based baby foods marketed in the Region of Valencia, Spain: levels and estimated daily intake.

Science.gov (United States)

Pardo-Marín, O; Yusà-Pelechà, V; Villalba-Martín, P; Perez-Dasí, J A

2010-04-01

This study was carried out to determine the current levels of nitrates in vegetables and vegetable-based baby foods (a total of 1150 samples) marketed in the Region of Valencia, Spain, over the period 2000-2008, and to estimate the toxicological risk associated with their intake. Average (median) levels of nitrate in lettuce, iceberg-type lettuce and spinach (1156, 798 and 1410 mg kg(-1) w/w, respectively) were lower than the maximum limits established by European Union legislation. Thirteen fresh spinach samples exceeded the regulatory limits. Median nitrate values in other vegetables for which a maximum limit has not been fixed by the European Commission were 196, 203, 1597, 96, 4474 and 2572 mg kg(-1) w/w (for potato, carrot, chard, artichoke, rucola and lamb's lettuce, respectively). The estimated nitrate daily intakes through vegetables consumption for adult, extreme consumers and children were found to be about 29%, 79.8% and 15.1%, respectively, of the acceptable daily intake (3.7 mg kg(-1)). The levels (median = 60.4 mg kg(-1) w/w) found in vegetable-based baby foods were, in all cases, lower the maximum level proposed by European Union legislation. The estimated nitrate daily intake through baby foods for infants between 0-1 and 1-2 years of age were 13% and 18%, respectively, of the acceptable daily intake.

Wild lettuce (Lactuca virosa) toxicity.

Science.gov (United States)

Besharat, Sima; Besharat, Mahsa; Jabbari, Ali

2009-01-01

Wild lettuce (Lactuca virosa) can cause toxic effects when eaten. Wild lettuce grows in the north of Iran and some natives consume it unaware of its adverse side effects. We describe eight patients with manifestations of wild lettuce toxicity, admitted to a general hospital affiliated to the Golestan University of Medical Sciences. All the patients recovered (although one had to spend 48 h in the intensive care unit) and no chronic complications were reported. A clinical suspicion of toxicity caused by wild lettuce intake and an accurate history formed the basis of the diagnosis. Conservative treatment, vital sign monitoring, control of patient intake and output, and reducing patient agitation provided the basis for treatment.

Genetic investigation of the nonhost resistance of wild lettuce, Lactuca saligna, to lettuce downy mildew, Bremia lactucae

NARCIS (Netherlands)

Boer, den E.

2014-01-01

Abstract

Downy mildew (Bremia lactucae) in lettuce (Lactuca sativa) is a devastating foliar disease causing high losses in lettuce cultivation. The wild lettuce and nonhost species, Lactuca saligna, is absolute resistant to downy mildew and

Dichroism in spinach chloroplasts

NARCIS (Netherlands)

Thomas, J.B.; Lierop, J.H. van; Ham, M. ten

1967-01-01

In spinach chloroplasts oriented at steel-water interfaces parallel to the light beam a distinct dichroism is measured at about 680 nm. This dichroism is minimal upon addition of sucrose up to a final concentration of 0.18 M to the medium, the dichroic ratio amounting to 1.02. It is concluded that

Physical and mechanical properties of spinach for whole-surface online imaging inspection

Science.gov (United States)

Tang, Xiuying; Mo, Chang Y.; Chan, Diane E.; Peng, Yankun; Qin, Jianwei; Yang, Chun-Chieh; Kim, Moon S.; Chao, Kuanglin

2011-06-01

The physical and mechanical properties of baby spinach were investigated, including density, Young's modulus, fracture strength, and friction coefficient. The average apparent density of baby spinach leaves was 0.5666 g/mm3. The tensile tests were performed using parallel, perpendicular, and diagonal directions with respect to the midrib of each leaf. The test results showed that the mechanical properties of spinach are anisotropic. For the parallel, diagonal, and perpendicular test directions, the average values for the Young's modulus values were found to be 2.137MPa, 1.0841 MPa, and 0.3914 MPa, respectively, and the average fracture strength values were 0.2429 MPa, 0.1396 MPa, and 0.1113 MPa, respectively. The static and kinetic friction coefficient between the baby spinach and conveyor belt were researched, whose test results showed that the average coefficients of kinetic and maximum static friction between the adaxial (front side) spinach leaf surface and conveyor belt were 1.2737 and 1.3635, respectively, and between the abaxial (back side) spinach leaf surface and conveyor belt were 1.1780 and 1.2451 respectively. These works provide the basis for future development of a whole-surface online imaging inspection system that can be used by the commercial vegetable processing industry to reduce food safety risks.

Occurrence of perchlorate in groundwater, paired farmland soil, lettuce, and rhizosphere soil from Chengdu, China.

Science.gov (United States)

Tang, Yulu; Zhong, Bifeng; Qu, Bing; Feng, Shujin; Ding, Sanglan; Su, Shijun; Li, Zhi; Gan, Zhiwei

2017-05-24

A total of 28 groundwater, paired farmland soil, lettuce, and its rhizosphere soil samples were collected from Chengdu, China to detect perchlorate levels and to evaluate the relationships of perchlorate concentrations among these matrices. The perchlorate concentrations in the groundwater, farmland soil, lettuce, and rhizosphere soil samples ranged from below detection limit to 60.2 μg L -1 , from below detection limit to 249 μg kg -1 dry weight (dw), from 2.07 to 1010 μg kg -1 wet weight, and from below detection limit to 314 μg kg -1 dw, respectively. Significant correlation was found in the perchlorate levels among the farmland soil, lettuce, and rhizosphere soil, suggesting that they have common pollution sources, or perchlorate might transfer from farmland soil-rhizosphere soil-plant. However, there is no significant correlation between groundwater and the other three matrices, indicating that infiltration from perchlorate contaminated farmland soil was not the predominant source for groundwater pollution in Chengdu. The perchlorate concentrations in the farmland soil and lettuce samples were significantly higher than those in the rhizosphere soil, primarily due to uptake of perchlorate through the rhizosphere micro-environment by lettuce, or accelerated degradation by rhizospheric microorganisms, which contributed more needs further investigation.

Wild lettuce (Lactuca virosa) toxicity

OpenAIRE

Besharat, Sima; Besharat, Mahsa; Jabbari, Ali

2009-01-01

Wild lettuce (Lactuca virosa) can cause toxic effects when eaten. Wild lettuce grows in the north of Iran and some natives consume it unaware of its adverse side effects. We describe eight patients with manifestations of wild lettuce toxicity, admitted to a general hospital affiliated to the Golestan University of Medical Sciences. All the patients recovered (although one had to spend 48 h in the intensive care unit) and no chronic complications were reported. A clinical suspicion of toxicity...

Classification of fecal contamination on leafy greens by hyperspectral imaging

Science.gov (United States)

Yang, Chun-Chieh; Jun, Won; Kim, Moon S.; Chao, Kaunglin; Kang, Sukwon; Chan, Diane E.; Lefcourt, Alan

2010-04-01

This paper reported the development of hyperspectral fluorescence imaging system using ultraviolet-A excitation (320-400 nm) for detection of bovine fecal contaminants on the abaxial and adaxial surfaces of romaine lettuce and baby spinach leaves. Six spots of fecal contamination were applied to each of 40 lettuce and 40 spinach leaves. In this study, the wavebands at 666 nm and 680 nm were selected by the correlation analysis. The two-band ratio, 666 nm / 680 nm, of fluorescence intensity was used to differentiate the contaminated spots from uncontaminated leaf area. The proposed method could accurately detect all of the contaminated spots.

Multi-residue determination of pharmaceutical and personal care products in vegetables.

Science.gov (United States)

Wu, Xiaoqin; Conkle, Jeremy Landon; Gan, Jay

2012-09-07

Treated wastewater irrigation and biosolid amendment are increasingly practiced worldwide and contamination of plants, especially produces that may be consumed raw by humans, by pharmaceutical and personal care products (PPCPs), is an emerging concern. A sensitive method was developed for the simultaneous measurement of 19 frequently-occurring PPCPs in vegetables using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) for detection, combined with ultrasonic extraction and solid phase extraction (SPE) cleanup for sample preparation. Deuterated standards were used as surrogates to quantify corresponding analytes. The corrected recoveries ranged between 87.1 and 123.5% for iceberg lettuce, with intra- and inter-day variations less than 20%, and the method detection limits (MDLs) in the range of 0.04-3.0 ng g⁻¹ dry weight (dw). The corrected recoveries were equally good when the method was used on celery, tomato, carrot, broccoli, bell pepper and spinach. The method was further applied to examine uptake of PPCPs by iceberg lettuce and spinach grown in hydroponic solutions containing each PPCP at 500 ng L⁻¹. Twelve PPCPs were detected in lettuce leaves with concentrations from 0.2 to 28.7 ng g⁻¹ dw, while 11 PPCPs were detected in spinach leaves at 0.04-34.0 ng g⁻¹ dw. Given the diverse chemical structures of PPCPs considered in this study, this method may be used for screening PPCP residues in vegetables and other plants impacted by treated wastewater or biosolids, and to estimate potential human exposure via dietary uptake. Copyright © 2012 Elsevier B.V. All rights reserved.

Escherichia coli Contamination of Lettuce Grown in Soils Amended with Animal Slurry

DEFF Research Database (Denmark)

Jensen, Annette Nygaard; Storm, Christina; Forslund, Anita

2013-01-01

A pilot study was conducted to assess the transfer of Escherichia coli from animal slurry fertilizer to lettuce, with E. coli serving as an indicator of fecal contamination and as an indicator for potential bacterial enteric pathogens. Animal slurry was applied as fertilizer to three Danish agric...... types between slurry, soil, and lettuce. The frequent finding of fecal-contaminated lettuce indicates that human pathogens such as Salmonella and Campylobacter can be present and represent food safety hazards.......A pilot study was conducted to assess the transfer of Escherichia coli from animal slurry fertilizer to lettuce, with E. coli serving as an indicator of fecal contamination and as an indicator for potential bacterial enteric pathogens. Animal slurry was applied as fertilizer to three Danish....... coli. A relatively higher frequency of E. coli in lettuce compared with the soil samples at harvest suggests environmental sources of fecal contamination, e.g., wildlife. The higher frequency was supported by the finding of 21 different PFGE types among the E. coli isolates, with only a few common PFGE...

Effect of alkyl-N-phenylcarbamates on photochemical activity of spinach chloroplasts

International Nuclear Information System (INIS)

Sersen, F.; Kralova, K.; Macho, V.

1999-01-01

This study is aimed to investigate the effect of alkyl-N-phenylcarbamates on photosynthetic electron transport in spinach chloroplasts, to determine site of action in the photosynthetic apparatus of spinach chloroplasts and to find correlations between their structure and biological activity. (authors)

Multifactorial effects of ambient temperature, precipitation, farm management, and environmental factors determine the level of generic Escherichia coli contamination on preharvested spinach.

Science.gov (United States)

Park, Sangshin; Navratil, Sarah; Gregory, Ashley; Bauer, Arin; Srinath, Indumathi; Szonyi, Barbara; Nightingale, Kendra; Anciso, Juan; Jun, Mikyoung; Han, Daikwon; Lawhon, Sara; Ivanek, Renata

2015-04-01

A repeated cross-sectional study was conducted to identify farm management, environment, weather, and landscape factors that predict the count of generic Escherichia coli on spinach at the preharvest level. E. coli was enumerated for 955 spinach samples collected on 12 farms in Texas and Colorado between 2010 and 2012. Farm management and environmental characteristics were surveyed using a questionnaire. Weather and landscape data were obtained from National Resources Information databases. A two-part mixed-effect negative binomial hurdle model, consisting of a logistic and zero-truncated negative binomial part with farm and date as random effects, was used to identify factors affecting E. coli counts on spinach. Results indicated that the odds of a contamination event (non-zero versus zero counts) vary by state (odds ratio [OR] = 108.1). Odds of contamination decreased with implementation of hygiene practices (OR = 0.06) and increased with an increasing average precipitation amount (mm) in the past 29 days (OR = 3.5) and the application of manure (OR = 52.2). On contaminated spinach, E. coli counts increased with the average precipitation amount over the past 29 days. The relationship between E. coli count and the average maximum daily temperature over the 9 days prior to sampling followed a quadratic function with the highest bacterial count at around 24°C. These findings indicate that the odds of a contamination event in spinach are determined by farm management, environment, and weather factors. However, once the contamination event has occurred, the count of E. coli on spinach is determined by weather only. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

A PCR procedure for the detection of Giardia intestinalis cysts and Escherichia coli in lettuce.

Science.gov (United States)

Ramirez-Martinez, M L; Olmos-Ortiz, L M; Barajas-Mendiola, M A; Giono Cerezo, S; Avila, E E; Cuellar-Mata, P

2015-06-01

Giardia intestinalis is a pathogen associated with foodborne outbreaks and Escherichia coli is commonly used as a marker of faecal contamination. Implementation of routine identification methods of G. intestinalis is difficult for the analysis of vegetables and the microbiological detection of E. coli requires several days. This study proposes a PCR-based assay for the detection of E. coli and G. intestinalis cysts using crude DNA isolated from artificially contaminated lettuce. The G. intestinalis and E. coli PCR assays targeted the β-giardin and uidA genes, respectively, and were 100% specific. Forty lettuces from local markets were analysed by both PCR and light microscopy and no cysts were detected, the calculated detection limit was 20 cysts per gram of lettuce; however, by PCR, E. coli was detected in eight of ten randomly selected samples of lettuce. These data highlight the need to validate procedures for routine quality assurance. These PCR-based assays can be employed as alternative methods for the detection of G. intestinalis and E. coli and have the potential to allow for the automation and simultaneous detection of protozoa and bacterial pathogens in multiple samples. Significance and impact of the study: There are few studies for Giardia intestinalis detection in food because methods for its identification are difficult for routine implementation. Here, we developed a PCR-based method as an alternative to the direct observation of cysts in lettuce by light microscopy. Additionally, Escherichia coli was detected by PCR and the sanitary quality of lettuce was evaluated using molecular and standard microbiological methods. Using PCR, the detection probability of Giardia cysts inoculated onto samples of lettuce was improved compared to light microscopy, with the advantage of easy automation. These methods may be employed to perform timely and affordable detection of foodborne pathogens. © 2015 The Society for Applied Microbiology.

Suppression Effects of Betaine-Enriched Spinach on Hyperhomocysteinemia Induced by Guanidinoacetic Acid and Choline Deficiency in Rats

Directory of Open Access Journals (Sweden)

Yi-Qun Liu

2014-01-01

Full Text Available Betaine is an important natural component of rich food sources, especially spinach. Rats were fed diets with betaine or spinach powder at the same level of betaine for 10 days to investigate the dose-dependent effects of spinach powder supplementation on hyperhomocysteinemia induced by guanidinoacetic acid (GAA addition and choline deprivation. The GAA-induced hyperhomocysteinemia in rats fed 25% casein diet (25C was significantly suppressed by supplementation with betaine or spinach, and it was completely suppressed by taking 11.0% spinach supplementation. The choline deprivation-induced enhancement of plasma homocysteine concentration in rats fed 25% soybean protein diet (25S was markedly suppressed by 3.82% spinach. Supplementation with betaine or spinach partially prevented the effects of GAA on hepatic concentrations of methionine metabolites. The decrease in activity of betaine-homocysteine S-methyltransferase (BHMT and cystathionine β-synthase (CBS in GAA-induced hyperhomocysteinemia was recovered by supplementation with betaine or spinach. Supplementation with betaine or spinach did not affect BHMT activity, whereas it partially restored CBS activity in choline-deprived 25S. The results indicated that betaine or spinach could completely suppress the hyperhomocysteinemia induced by choline deficiency resulting from stimulating the homocysteine removal by both remethylation and cystathionine formation.

Uptake of different species of iodine by water spinach and its effect to growth.

Science.gov (United States)

Weng, Huan-Xin; Yan, Ai-Lan; Hong, Chun-Lai; Xie, Lin-Li; Qin, Ya-Chao; Cheng, Charles Q

2008-08-01

A hydroponic experiment has been carried out to study the influence of iodine species [iodide (I(-)), iodate (IO(-)(3)), and iodoacetic acid (CH(2)ICOO(-))] and concentrations on iodine uptake by water spinach. Results show that low levels of iodine in the nutrient solution can effectively stimulate the growth of biomass of water spinach. When iodine levels in the nutrient solution are from 0 to 1.0 mg/l, increases in iodine levels can linearly augment iodine uptake rate by the leafy vegetables from all three species of iodine, and the uptake effects are in the following order: CH(2)ICOO(-) >I(-)>IO(-)(3). In addition, linear correlation was observed between iodine content in the roots and shoots of water spinach, and their proportion is 1:1. By uptake of I(-), vitamin C (Vit C) content in water spinach increased, whereas uptake of IO(-)(3) and CH(2)ICOO(-) decreased water spinach Vit C content. Furthermore, through uptake of I(-) and IO(-)(3). The nitrate content in water spinach was increased by different degrees.

Folate Biofortification in Hydroponically Cultivated Spinach by the Addition of Phenylalanine.

Science.gov (United States)

Watanabe, Sho; Ohtani, Yuta; Tatsukami, Yohei; Aoki, Wataru; Amemiya, Takashi; Sukekiyo, Yasunori; Kubokawa, Seiichi; Ueda, Mitsuyoshi

2017-06-14

Folate is an important vitamin mainly ingested from vegetables, and folate deficiency causes various health problems. Recently, several studies demonstrated folate biofortification in plants or food crops by metabolic engineering through genetic modifications. However, the production and sales of genetically modified foods are under strict regulation. Here, we developed a new approach to achieve folate biofortification in spinach (Spinacia oleracea) without genetic modification. We hydroponically cultivated spinach with the addition of three candidate compounds expected to fortify folate. As a result of liquid chromatography tandem mass spectrometry analysis, we found that the addition of phenylalanine increased the folate content up to 2.0-fold (306 μg in 100 g of fresh spinach), representing 76.5% of the recommended daily allowance for adults. By measuring the intermediates of folate biosynthesis, we revealed that phenylalanine activated folate biosynthesis in spinach by increasing the levels of pteridine and p-aminobenzoic acid. Our approach is a promising and practical approach to cultivate nutrient-enriched vegetables.

Impact of Sweet Potato Starch-Based Nanocomposite Films Activated With Thyme Essential Oil on the Shelf-Life of Baby Spinach Leaves

Directory of Open Access Journals (Sweden)

Aseel Issa

2017-06-01

Full Text Available Salmonella Typhimurium (S. Typhi and Escherichia coli (E. coli have been responsible for an increasing number of outbreaks linked to fresh produce, such as baby spinach leaves, in the last two decades. More recently, antimicrobial biodegradable packaging systems have been attracting much attention in the food packaging industry as eco-friendly alternatives to conventional plastic packaging. The objective of this study was to evaluate the effect of antibacterial nanocomposite films on inoculated spinach leaves and on the sensory properties of these leaves during eight days of refrigerated storage. In this study, an antibacterial film comprised of sweet potato starch (SPS, montmorillonite (MMT nanoclays and thyme essential oil (TEO as a natural antimicrobial agent was developed. Our results showed that the incorporation of TEO in the film significantly (p < 0.05 reduced the population of E. coli and S. Typhi on fresh baby spinach leaves to below detectable levels within five days, whereas the control samples without essential oil maintained approximately 4.5 Log colony forming unit (CFU/g. The sensory scores for spinach samples wrapped in films containing TEO were higher than those of the control. This study thus suggests that TEO has the potential to be directly incorporated into a SPS film to prepare antimicrobial nanocomposite films for food packaging applications.

Evaluation of Lettuce Genotypes for Seed Thermotolerance

Science.gov (United States)

Thermoinhibition of lettuce (Lactuca sativa L.) seed germination is a common problem associated with lettuce production. Depending on lettuce cultivars, seed germination may be inhibited when temperatures exceed 28oC. The delay or inhibition of seed germination at high temperatures may reduce seedli...

Characterization of lettuce big-vein associated virus and Mirafiori lettuce big-vein virus infecting lettuce in Saudi Arabia.

Science.gov (United States)

Umar, M; Amer, M A; Al-Saleh, M A; Al-Shahwan, I M; Shakeel, M T; Zakri, A M; Katis, N I

2017-07-01

During 2014 and 2015, 97 lettuce plants that showed big-vein-disease-like symptoms and seven weed plants were collected from the Riyadh region. DAS-ELISA revealed that 25% and 9% of the lettuce plants were singly infected with LBVaV and MiLBVV, respectively, whereas 63% had a mixed infection with both viruses. The results were confirmed by multiplex reverse transcription polymerase chain reaction using primers specific for LBVaV and MiLBVV. LBVaV and MiLBVV were also detected in Sonchus oleraceus and Eruca sativa, respectively. The nucleotide sequence of LBVaV and MiLBVV Saudi isolates ranged from 94.3-100%, and their similarities to isolates with sequences in the GenBank database ranged from 93.9 to 99.6% and 93.8 to 99.3%, respectively. Olpidium sp. was present in the roots of lettuce plants with big-vein disease and it was shown to facilitate transmission of both viruses.

Partial aphid resistance in lettuce negatively affects parasitoids.

Science.gov (United States)

Lanteigne, Marie-Eve; Brodeur, Jacques; Jenni, Sylvie; Boivin, Guy

2014-10-01

This study investigated the effects of partial plant resistance on the lettuce aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), a major pest of cultivated lettuce (Lactuca sativa L.), and one of its parasitoids, Aphidius ervi Haliday (Hymenoptera: Braconidae). Aphids were reared on susceptible (L. sativa variety Estival; S) or partially resistant (Lactuca serriola L. PI 491093; PR) lettuce, and next parasitized by A. ervi females. Fitness proxies were measured for both aphids and parasitoids. Developmental time to adult stage took longer for alate and apterous aphids (an average of 3.5 and 1.5 additional days, respectively) on PR than on S lettuce, and fecundity of alate aphids reared on PR lettuce was reduced by 37.8% relative to those reared on S lettuce. Size (tibia length) and weight of aphids reared on PR lettuce were lower than for aphids reared on S lettuce from the third and second instar onward, respectively. Parasitism of aphids reared on PR plants resulted in lower parasitoid offspring emergence (-49.9%), lower adult female (-30.3%) and male (-27.5%) weight, smaller adult female (-17.5%) and male (-11.9%) size, and lower female fecundity (37.8% fewer eggs) than when parasitoids developed from aphids reared on S plants. Our results demonstrate that partial aphid resistance in lettuce negatively affects both the second and third trophic levels. Host plant resistance in cultivated lettuce may therefore create an ecological sink for aphid parasitoids.

Lettuce Allergy Is a Lipid Transfer Syndrome-Related Food Allergy With a High Risk of Severe Reactions.

Science.gov (United States)

Muñoz-García, E; Luengo-Sánchez, O; Moreno-Pérez, N; Cuesta-Herranz, J; Pastor-Vargas, C; Cardona, V

Lipid transfer protein (LTP) sensitization is the most common cause of food allergy in the Mediterranean area, with peach allergy acting as the primary sensitizer in most cases. Lettuce has been described as a common offending food in patients with LTP syndrome. The aim of the study was to investigate the frequency and clinical expression of LTP syndrome in a sample of lettuceallergic patients. We determined specific IgE to Pru p 3 and lettuce in a sample of 30 patients with a diagnosis of lettuce allergy. Symptoms elicited by other LTP-containing plant-derived foods and the presence of cofactors were assessed. The clinical symptoms of lettuce allergy were frequently severe, with 18 of the 30 patients experiencing anaphylaxis. All the patients had allergic reactions to other plant foods. Cofactors were involved in the clinical reactions of 13 of the 30 patients. Sensitization to pollens was found in 90% of patients. Lettuce allergy is found not as an isolated condition but in the context of LTP syndrome and it is characterized by severe reactions and frequent cofactor association.

In-package inhibition of E.coli 0157:H7 on bulk romaine lettuce using cold plasma

Science.gov (United States)

Dielectric barrier discharge atmospheric cold plasma (DACP) treatment was evaluated for the inactivation of Escherichia coli O157:H7, surface morphology, color, carbon dioxide generation, and weight loss of bulk Romaine lettuce in a commercial plastic clamshell container. The lettuce samples were pa...

Interaction between Silver Nanoparticles and Spinach Leaf

Science.gov (United States)

Tian, Y.; Li, H.; Zhang, Y.; Riser, E.; He, S.; Zhang, W.

2013-12-01

Interactions of engineered nanoparticles (ENPs) with plant surfaces are critical to assessing the bioavailability of ENPs to edible plants and to further evaluating impacts of ENPs on ecological health and food safety. Silver nanoparticles (i.e., nanoAg) could enter the agroecosystems either as an active ingredient in pesticides or from other industrial and consumer applications. Thus, in the events of pesticide application, rainfall, and irrigation, vegetable leaves could become in contact and then interact with nanoAg. The present study was to assess whether the interaction of nanoAg with spinach leaves can be described by classical sorption models and to what extent it depends on and varies with dispersion methods, environmental temperature, and ion release. We investigated the stability and ion release of nanoAg dispersed by sodium dodecyl sulfate (SDS, 1%) and humic acid (HA, 10 mg C/L) solutions, as well as sorption and desorption of nanoAg on and from the fresh spinach leaf. Results showed SDS-nanoAg released about 2%-8% more Ag ion than HA-nanoAg. The sorption of Ag ion, described by the Freundlich model in the initial concentration range of 0.6-50 mg/L, was 2-4 times higher than that of nanoAg. The sorption of nanoAg on spinach leaf can be fitted by the Langmuir model, and the maximum sorption amount of HA-nanoAg and SDS-nanoAg was 0.21 and 0.41 mg/g, respectively. The higher sorption of SDS-nanoAg relative to that of HA-nanoAg could be partially resulted from the higher release of Ag ion from the former. The maximum desorption amount of HA-nanoAg and SDS-nanoAg in 1% SDS solution was 0.08 and 0.10 mg/g, respectively. NanoAg attachment on and its penetration to the spinach leaf was visualized by the Scanning Electron Microscope equipped with an Energy Dispersive Spectrometer (SEM-EDS). It is equally important that the less sorption of nanoAg under low environmental temperature could be partially due to the closure of stomata, as verified by SEM-EDS. Cyto

Irrigation Water Sources and Time Intervals as Variables on the Presence of Campylobacter spp. and Listeria monocytogenes on Romaine Lettuce Grown in Muck Soil.

Science.gov (United States)

Guévremont, Evelyne; Lamoureux, Lisyanne; Généreux, Mylène; Côté, Caroline

2017-07-01

Irrigation water has been identified as a possible source of vegetable contamination by foodborne pathogens. Risk management for pathogens such as Campylobacter spp. and Listeria monocytogenes in fields can be influenced by the source of the irrigation water and the time interval between last irrigation and harvest. Plots of romaine lettuce were irrigated with manure-contaminated water or aerated pond water 21, 7, or 3 days prior to harvesting, and water and muck soil samples were collected at each irrigation treatment. Lettuce samples were collected at the end of the trials. The samples were tested for the presence of Campylobacter spp. and L. monocytogenes. Campylobacter coli was isolated from 33% of hog manure samples (n = 9) and from 11% of the contaminated water samples (n = 27), but no lettuce samples were positive (n = 288). L. monocytogenes was not found in manure, and only one sample of manure-contaminated irrigation water (n = 27) and one lettuce sample (n = 288) were positive. No Campylobacter or L. monocytogenes was recovered from the soil samples (n = 288). Because of the low incidence of pathogens, it was not possible to link the contamination of either soil or lettuce with the type of irrigation water. Nevertheless, experimental field trials mimicking real conditions provide new insights into the survival of two significant foodborne pathogens on romaine lettuce.

Cadmium uptake in above-ground parts of lettuce (Lactuca sativa L.).

Science.gov (United States)

Tang, Xiwang; Pang, Yan; Ji, Puhui; Gao, Pengcheng; Nguyen, Thanh Hung; Tong, Yan'an

2016-03-01

Because of its high Cd uptake and translocation, lettuce is often used in Cd contamination studies. However, there is a lack of information on Cd accumulation in the above-ground parts of lettuce during the entire growing season. In this study, a field experiment was carried out in a Cd-contaminated area. Above-ground lettuce parts were sampled, and the Cd content was measured using a flame atomic absorption spectrophotometer (AAS). The results showed that the Cd concentration in the above-ground parts of lettuce increased from 2.70 to 3.62mgkg(-1) during the seedling stage, but decreased from 3.62 to 2.40mgkg(-1) during organogenesis and from 2.40 to 1.64mgkg(-1) during bolting. The mean Cd concentration during the seedling stage was significantly higher than that during organogenesis (a=0.05) and bolting (a=0.01). The Cd accumulation in the above-ground parts of an individual lettuce plant could be described by a sigmoidal curve. Cadmium uptake during organogenesis was highest (80% of the total), whereas that during bolting was only 4.34%. This research further reveals that for Rome lettuce: (1) the highest Cd content of above-ground parts occurred at the end of the seedling phase; (2) the best harvest time with respect to Cd phytoaccumulation is at the end of the organogenesis stage; and (3) the organogenesis stage is the most suitable time to enhance phytoaccumulation efficiency by adjusting the root:shoot ratio. Copyright © 2015 Elsevier Inc. All rights reserved.

Silencing the lettuce homologs of small rubber particle protein does not influence natural rubber biosynthesis in lettuce (Lactuca sativa).

Science.gov (United States)

Chakrabarty, Romit; Qu, Yang; Ro, Dae-Kyun

2015-05-01

Natural rubber, cis-1,4-polyisoprene, is an important raw material in chemical industries, but its biosynthetic mechanism remains elusive. Natural rubber is known to be synthesized in rubber particles suspended in laticifer cells in the Brazilian rubber tree (Hevea brasiliensis). In the rubber tree, rubber elongation factor (REF) and its homolog, small rubber particle protein (SRPP), were found to be the most abundant proteins in rubber particles, and they have been implicated in natural rubber biosynthesis. As lettuce (Lactuca sativa) can synthesize natural rubber, we utilized this annual, transformable plant to examine in planta roles of the lettuce REF/SRPP homologs by RNA interference. Among eight lettuce REF/SRPP homologs identified, transcripts of two genes (LsSRPP4 and LsSRPP8) accounted for more than 90% of total transcripts of REF/SRPP homologs in lettuce latex. LsSRPP4 displays a typical primary protein sequence as other REF/SRPP, while LsSRPP8 is twice as long as LsSRPP4. These two major LsSRPP transcripts were individually and simultaneously silenced by RNA interference, and relative abundance, polymer molecular weight, and polydispersity of natural rubber were analyzed from the LsSRPP4- and LsSRPP8-silenced transgenic lettuce. Despite previous data suggesting the implications of REF/SRPP in natural rubber biosynthesis, qualitative and quantitative alterations of natural rubber could not be observed in transgenic lettuce lines. It is concluded that lettuce REF/SRPP homologs are not critically important proteins in natural rubber biosynthesis in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid detection of Salmonella typhimurium on fresh spinach leaves using phage-immobilized magnetoelastic biosensors

Science.gov (United States)

Horikawa, Shin; Li, Suiqiong; Chai, Yating; Park, Mi-Kyung; Shen, Wen; Barbaree, James M.; Vodyanoy, Vitaly J.; Chin, Bryan A.

2011-06-01

This paper presents an investigation into the use of magnetoelastic biosensors for the rapid detection of Salmonella typhimurium on fresh spinach leaves. The biosensors used in this investigation were comprised of a strip-shaped, goldcoated sensor platform (2 mm-long) diced from a ferromagnetic, amorphous alloy and a filamentous fd-tet phage which specifically binds with S. typhimurium. After surface blocking with bovine serum albumin, these biosensors were, without any preceding sample preparation, directly placed on wet spinach leaves inoculated with various concentrations of S. typhimurium. Upon contact with cells, the phage binds S. typhimurium to the sensor thereby increasing the total mass of the sensor. This change in mass causes a corresponding decrease in the sensor's resonant frequency. After 25 min, the sensors were collected from the leaf surface and measurements of the resonant frequency were performed immediately. The total assay time was less than 30 min. The frequency changes for measurement sensors (i.e., phageimmobilized) were found to be statistically different from those for control sensors (sensors without phage), down to 5 × 106 cells/ml. The detection limit may be improved by using smaller, micron-sized sensors that will have a higher probability of contacting Salmonella on the rough surfaces of spinach leaves.

Phosphate effect on the content of selected elements in a lettuce variety grown at a contaminated soil

International Nuclear Information System (INIS)

Armelin, M.J.A.; Saiki, M.; Maihara, V.A.; Moreira, E.G.; Trevizam, A.R.; Muraoka, T.; Silva, M.L.S.

2014-01-01

The purpose of this study was to evaluate the efficiency of superphosphate fertilizer in remediating a contaminated soil with potentially toxic elements. For this, different phosphorus doses were used in a number of lettuce plants. The element concentrations determined in their leaves were compared with those found in control lettuce plants. Instrumental neutron activation analysis was the analytical technique used to determine element concentration in lettuce leave samples. The application of 250 mg kg -1 of P was the most effective treatment to reduce the concentrations of Br, Ca, Cd, Cl, Co, Cr, Fe, K, Mg, Mn, Sb and Zn in lettuce leaves. (author)

Proteomic Analysis of Lettuce Seed Germination and Thermoinhibition by Sampling of Individual Seeds at Germination and Removal of Storage Proteins by Polyethylene Glycol Fractionation1

Science.gov (United States)

Song, Bin-Yan; Deng, Zhi-Jun; Wang, Yue; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

2015-01-01

Germination and thermoinhibition in lettuce (Lactuca sativa ‘Jianyexianfeng No. 1’) seeds were investigated by a proteomic comparison among dry seeds, germinated seeds at 15°C, at 15°C after imbibition at 25°C for 48 h, or at 25°C in KNO3 (all sampled individually at germination), and ungerminated seeds at 25°C, a thermoinhibitory temperature. Before two-dimensional gel electrophoresis analysis, storage proteins (greater than 50% of total extractable protein) were removed by polyethylene glycol precipitation, which significantly improved the detection of less abundant proteins on two-dimensional gels. A total of 108 protein spots were identified to change more than 2-fold (P lettuce seed germination and thermoinhibition. Accumulation of three proteins and expression of five genes participating in the mevalonate (MVA) pathway of isoprenoid biosynthesis correlated positively with seed germinability. Inhibition of this pathway by lovastatin delayed seed germination and increased the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination and thermoinhibition. PMID:25736209

Growing patterns to produce 'nitrate-free' lettuce (Lactuca sativa).

Science.gov (United States)

Croitoru, Mircea Dumitru; Muntean, Daniela-Lucia; Fülöp, Ibolya; Modroiu, Adriana

2015-01-01

Vegetables can contain significant amounts of nitrate and, therefore, may pose health hazards to consumers by exceeding the accepted daily intake for nitrate. Different hydroponic growing patterns were examined in this work in order to obtain 'nitrate-free lettuces'. Growing lettuces on low nitrate content nutrient solution resulted in a significant decrease in lettuces' nitrate concentrations (1741 versus 39 mg kg(-1)), however the beneficial effect was cancelled out by an increase in the ambient temperature. Nitrate replacement with ammonium was associated with an important decrease of the lettuces' nitrate concentration (from 1896 to 14 mg kg(-1)) and survival rate. An economically feasible method to reduce nitrate concentrations was the removal of all inorganic nitrogen from the nutrient solution before the exponential growth phase. This method led to lettuces almost devoid of nitrate (10 mg kg(-1)). The dried mass and calcinated mass of lettuces, used as markers of lettuces' quality, were not influenced by this treatment, but a small reduction (18%, p < 0.05) in the fresh mass was recorded. The concentrations of nitrite in the lettuces and their modifications are also discussed in the paper. It is possible to obtain 'nitrate-free' lettuces in an economically feasible way.

Exploratory Study into the Microbiological Quality of Spinach and Cabbage Purchased from Street Vendors and Retailers in Johannesburg, South Africa.

Science.gov (United States)

Plessis, Erika M du; Govender, Sarasha; Pillay, Bala; Korsten, Lise

2017-10-01

Knowledge of the microbiological quality and prevalence of antibiotic resistance and virulence genes in bacterial isolates from leafy green vegetables supplied by formal suppliers (retailers) and informal suppliers (street vendors) in South Africa is limited. Because leafy vegetables have been implicated in foodborne disease outbreaks worldwide, 180 cabbage and spinach samples were collected from three major retailers and nine street vendors in Johannesburg, South Africa. Escherichia coli and coliforms were enumerated using Petrifilm plates. The prevalence of Listeria monocytogenes, Salmonella, and Shigella was determined using real-time PCR analysis. Identities of presumptive E. coli isolates from the fresh produce were confirmed using matrix-assisted laser desorption-ionization time of flight mass spectroscopy. Isolates were characterized using phenotypic (antibiotic resistance) and genotypic (phylogenetic and virulence gene) analysis. Hygiene indicator bacteria levels on spinach from formal and informal retailers exceeded the maximum level specified by the Department of Health guidelines for fresh fruit and vegetables. E. coli counts for street vendor spinach were higher (P analysis; Shigella was not detected. Of the 29 spinach E. coli isolates, 37.9% were multidrug resistant. Virulence genes eae and stx 1 were present in 14 and 3% of the spinach E. coli isolates, respectively; the stx 2 gene was not detected. Eighty-six percent of these isolates belonged to phylogroup A, 3% belonged to group C, 7% belonged to group E, and 3% belonged to clade 1. The results from the current exploratory study on the microbiological quality of spinach bought from selected retailers highlight the need for continued surveillance on a larger scale, especially in the informal sector, to characterize the potential health risks to the consumer.

Advancements in utilizing molecular markers in lettuce breeding

Science.gov (United States)

Lettuce (Lactuca sativa L.) is globally the most popular commercially produced, leafy vegetable, farmed in moderate climates. Cultivated lettuce is a self-fertilizing, diploid (2n = 2x = 18) species from the family Compositae (Asteraceae). New cultivars of lettuce are developed by combining desirabl...

Evidence for Lettuce big-vein associated virus as the causal agent of a syndrome of necrotic rings and spots in lettuce

NARCIS (Netherlands)

Verbeek, M.; Dullemans, A.M.; Bekkum, van P.J.; Vlugt, van der R.A.A.

2013-01-01

Lettuce big-vein associated virus (LBVaV, genus Varicosavirus) was shown to be responsible for characteristic necrotic symptoms observed in combination with big-vein symptoms in lettuce breeding lines when tested for their susceptibility to lettuce big-vein disease (BVD) using viruliferous Olpidium

Freqüência de enteroparasitas em amostras de alface (Lactuca sativa comercializadas em Lavras, Minas Gerais Frequency of intestinal parasites in samples of lettuce (Lactuca sativa commercialized in Lavras, Minas Gerais State

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Antônio Marcos Guimarães

2003-10-01

Full Text Available O objetivo deste trabalho foi realizar uma avaliação parasitológica em amostras de alface (Lactuca sativa comercializadas em Lavras, MG. As amostras de alfaces apresentaram baixos padrões higiênicos, indicados pela presença de formas parasitológicas de origem animal ou humana e alta concentração de coliformes fecais.The aim of this study was to evaluate the parasitological contamination in samples of lettuce (Lactuca sativa commercialized in Lavras city, Minas Gerais. The samples of lettuce showed low hygienic conditions, indicated by the presence of parasites of animal or human origin and high concentration of fecal coliforms.

Effect of gamma radiation on the reduction of Salmonella strains, Listeria monocytogenes, and Shiga toxin-producing Escherichia coli and sensory evaluation of minimally processed spinach (Tetragonia expansa).

Science.gov (United States)

Rezende, Ana Carolina B; Igarashi, Maria Crystina; Destro, Maria Teresa; Franco, Bernadette D G M; Landgraf, Mariza

2014-10-01

This study evaluated the effects of irradiation on the reduction of Shiga toxin-producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10 -values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

Internalization of Sapovirus, a Surrogate for Norovirus, in Romaine Lettuce and the Effect of Lettuce Latex on Virus Infectivity

Science.gov (United States)

Esseili, Malak A.; Zhang, Zhenwen

2012-01-01

Noroviruses are the leading cause of food-borne outbreaks, including those that involve lettuce. The culturable porcine sapovirus (SaV) was used as a norovirus surrogate to study the persistence and the potential transfer of the virus from roots to leaves and from outer to inner leaves of lettuce plants. Treatment of lettuce with SaV was done through the roots of young plants, the soil, or the outer leaves of mature plants. Sampling of roots, xylem sap, and inner and outer leaves followed by RNA extraction and SaV-specific real-time reverse transcription (RT)-PCR was performed at 2 h and on postinoculation days (PID) 2, 5, 7, 14, and/or 28. When SaV was inoculated through the roots, viral RNA persisted on the roots and in the leaves until PID 28. When the virus was inoculated through the soil, viral RNA was detected on the roots and in the xylem sap until PID 14; viral RNA was detected in the leaves only until PID 2. No infectious virus was detected inside the leaves for either treatment. When SaV was inoculated through the outer leaves, viral RNA persisted on the leaves until PID 14; however, the virus did not transfer to inner leaves. Infectious viral particles on leaves were detected only at 2 h postinoculation. The milky sap (latex) of leaves, but not the roots' xylem sap, significantly decreased virus infectivity when tested in vitro. Collectively, our results showed the transfer of SaV from roots to leaves through the xylem system and the capacity of the sap of lettuce leaves to decrease virus infectivity in leaves. PMID:22752176

Efficacy of chlorine dioxide on Escherichia coli inactivation during pilot-scale fresh-cut lettuce processing.

Science.gov (United States)

Banach, J L; van Overbeek, L S; Nierop Groot, M N; van der Zouwen, P S; van der Fels-Klerx, H J

2018-03-23

Controlling water quality is critical in preventing cross-contamination during fresh produce washing. Process wash water (PWW) quality can be controlled by implementing chemical disinfection strategies. The aim of this study was to evaluate the pilot-scale efficacy of chlorine dioxide (ClO 2 ) during processing on the reduction of Escherichia coli in the PWW and on processed fresh-cut 'Lollo Rossa' lettuce. The objective was to have a residual target concentration of either 5 or 3 mg/L ClO 2 in the washing tank (3.5 m 3 ) before and during 800 kg of lettuce processing (90 min). After 90 min., a nonpathogenic, non-Extended Spectrum Beta-Lactamase (ESBL) E. coli inoculum from an overnight culture broth (37 °C) was added to the tank resulting in an approximate final level of 10 6  CFU/mL. PWW and lettuce samples for microbiological and chemical analyses were taken before and after the input and supply halted. ClO 2 concentrations quickly decreased after ClO 2 input halted, yet a residual concentration of ≥2.5 mg/L and ≥2.1 mg/L ClO 2 , respectively for 5 and 3 mg/L pilots, was present 12 min after the supply halted. No detectable levels of E. coli (limit of detection 5 log) were determined in the water within 1 min after E. coli was added to the ClO 2 containing wash water. Results demonstrated that ClO 2 use at the semi-commercial pilot scale was able to reduce the E. coli peak contamination in the PWW. After storage (5 days, 4 °C), background microbial communities (i.e., fluorescent Pseudomonads and total heterotrophic bacteria) grew out on lettuce. Overall, ClO 2 decreased the potential for cross-contamination between batches compared to when no sanitizer was used. Chlorate levels of the lettuce sampled before entering the wash water ranged from 7.3-11.6 μg/kg. The chlorate levels of the lettuce sampled after being washed in the ClO 2 containing wash water, as well as after rinsing and centrifugation, ranged from 22.8-60.4�

Ocorrência generalizada do Lettuce mottle virus em três regiões produtoras de alface comercial do Estado de São Paulo Occurrence of Lettuce mottle virus on three lettuce producing areas from São Paulo State

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Renate Krause-Sakate

2008-02-01

Full Text Available Os sequivírus são vírus isométricos transmitidos por afídeos. Lettuce mottle virus (LeMoV, um provável sequivirus foi descrito no Brasil em 1982 e causa sintomas de mosaico semelhantes aos observados pelo Lettuce mosaic virus (LMV. Um levantamento para ocorrência do LeMoV nos campos de produção de alface de três diferentes regiões do Estado de São Paulo (Mogi das Cruzes, Campinas e Bauru foi realizado durante 2002 a 2005. RNA total foi extraído e utilizado na detecção, em RT-PCR, com oligonucleotídeos específicos para o LeMoV. Do total de 1362 amostras, 137 (10,05% foram positivas para o LeMoV. Infecção mista com o LMV foi verificada em 43 amostras (31,4%. Foi verificada a ocorrência do LeMoV nas três diferentes regiões analisadas, porém sua ocorrência foi baixa nas diferentes épocas do ano.Sequiviruses are isometric aphid-borne plant viruses. Lettuce mottle virus (LeMoV, a putative sequivirus was first described in Brazil on 1982 causing similar mosaic symptoms as Lettuce mosaic virus (LMV. A survey for the occurrence of LeMoV on open field conditions was carried out during 2002 to 2005 on Mogi das Cruzes, Campinas and Bauru in São Paulo state. Total RNA was extracted and used on RT-PCR with specific LeMoV primers. On 1362 samples tested, 137 (10,05% were positive for LeMoV. Mixed infections with LMV was observed on 43 samples (31,4%. The presence of LeMoV was observed in the three different regions, but with low incidence during the year.

Effect of low-temperature plasma on the degradation of omethoate residue and quality of apple and spinach

Science.gov (United States)

Xingmin, SHI; Jinren, LIU; Guimin, XU; Yueming, WU; Lingge, GAO; Xiaoyan, LI; Yang, YANG; Guanjun, ZHANG

2018-04-01

Dielectric barrier corona discharge was developed to generate low-temperature plasma (LTP) to treat apple and spinach samples contaminated with omethoate. Experimental results showed that, after 20 min exposure, the degradation rate of omethoate residue in apple and spinach was (94.55 ± 0.01)% and (95.55 ± 0.01)%, respectively. When the treatment time was shorter than 20 min, the contents of moisture, vitamin C and beta-carotene were not affected by LTP. Exploration of related mechanisms suggested that LTP might destroy unsaturated double bonds of omethoate and produce phosphate ion, eventually leading to omethoate destruction. It is concluded that appropriate dosage of LTP can effectively degrade omethoate residue in fruits and vegetables without affecting their quality.

Phytoextraction and estimating optimal time for remediation of Cd-contaminated soils by Spinach

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Somayyeh Eisazadeh Lazarjan

2016-05-01

Full Text Available The so-called phytoextraction in which hyperaccumulator plants are used to remediate the contaminated soils is proven to be an efficient method. The objective of this study was to investigate the capability of Spinach for phytoremediation of cadmium from Cd-contaminated soils and determine the efficiency extent of spinach for phytoremediation. For this purpose, a randomized block experimental design whit five treatments including 0, 15, 30, 60 and 120 mg Cd/ kg soil and three replications was established in the greenhouse. After contamination the soils with different levels of cadmium, spinach seeds were planted. When plants were fully developed, plants were harvested and their cadmium contents in shoot and roots as well as the soil-cadmium were measured. The results indicated that by increasing Cd concentration in soil, the major Cd accumulation was occurred in the roots rather than shoots. Maximum cadmium concentration within the shoots and roots was 73.7 and 75.86 mg/kg soil, respectively. According to Spinach ability to absorb high concentration of cadmium in the root zone and its high biomass and capability of Cadmium accumulation in shoots, Spinach can be used as hyperaccumulator plant to remediate cadmium from Cd-contaminated soils. But, according to minimum remediation time and maximum dry matter for the 30 mg Cd/ kg soil, maximum Cd extracted by shoots in hectare/year was in 30 mg Cd/ kg soil. It can be concluded that Spinach is a suitable plant for phytoremediation of slightly and to moderately cadmium contaminated soils.

In-package inhibition of E. coli O157:H7 on bulk Romaine lettuce using cold plasma.

Science.gov (United States)

Min, Sea C; Roh, Si Hyeon; Niemira, Brendan A; Boyd, Glenn; Sites, Joseph E; Uknalis, Joseph; Fan, Xuetong

2017-08-01

Dielectric barrier discharge atmospheric cold plasma (DACP) treatment was evaluated for the inactivation of Escherichia coli O157:H7, surface morphology, color, carbon dioxide generation, and weight loss of bulk Romaine lettuce in a commercial plastic clamshell container. The lettuce samples were packed in a model bulk packaging configuration (three rows with either 1, 3, 5, or 7 layers) in the container and treated by DACP (42.6 kV, 10 min). DACP treatment reduced the number of E. coli O157:H7 in the leaf samples in the 1-, 3-, and 5-layer configurations by 0.4-0.8 log CFU/g lettuce, with no significant correlation to the sample location (P > 0.05). In the largest bulk stacking with 7 layers, a greater degree of reduction (1.1 log CFU/g lettuce) was observed at the top layer, but shaking the container increased the uniformity of the inhibition. DACP did not significantly change the surface morphology, color, respiration rate, or weight loss of the samples, nor did these properties differ significantly according to their location in the bulk stack. DACP treatment inhibited E. coli O157:H7 on bulk lettuce in clamshell containers in a uniform manner, without affecting the physical and biological properties and thus holds promise as a post-packaging process for fresh and fresh-cut fruits and vegetables. Published by Elsevier Ltd.

Irradiation of lettuce (Lactuca sativa. L.): microbiological and sensory aspects;Irradiacao de alface (Lactuca sativa. L.): aspectos microbiologicos e sensoriais

Energy Technology Data Exchange (ETDEWEB)

Tsuhako, Vanessa Provenzano

2005-07-01

The increasing demand for fresh foods have stimulated the marketing of minimally processed vegetables. However, these products maintain most of their natural microbiota even after being sanitized, including pathogenic microorganisms. Refrigerated storage allows the growth of psychotropic microorganisms and among them the pathogen Listeria monocytogenes. The ingestion of food contaminated with L. monocytogenes may represent a risk to pregnant women and their fetuses and to immunocompromised people. Non-thermal alternative processes for food preservation, such as irradiation, can reduce pathogenic and spoilage microorganism populations without impairing substantial changes in sensory, physical or chemical attributes. The aims of this research were to evaluate the effect of gamma radiation on L. monocytogenes artificially inoculated on minimally processed lettuce, to evaluate its effect on lettuce leaves through acceptance sensory test and to determine the irradiated vegetable shelf life through sensory and microbiological tests. A mixture of 4 types of lettuce (Iceberg, Boston, Loose-leaf and Red loose-leaf) were artificially inoculated with L. monocytogenes (7 log UFC/g lettuce) and then exposed to 0.3; 0.6; 0.9 and 1.2 kGy, under refrigeration. The DlO values for L. monocytogenes varied fram 0.18 to 0.21 kGy. Sensory and microbiological tests indicated that the shelf life of Iceberg lettuce stored at 7 deg C was 5 and 7 days for the irradiated and non-irradiated samples, respectively, and for the irradiated and non-irradiated Loose-leaf lettuce samples were 10 days. For the non-irradiated Boston sample, the shelf life was 3 days and for the Irradiated 7 days. Red loose-leaf showed 5 and 4 days of shelf lives for the irradiated and non-irradiated, respectively. Irradiated samples presented better microbiological quality than non-irradiated ones. The irradiation is feasible process to improve quality and safety of lettuce leaves. (author)

Occurrence of Coliform and Escherichia coli Contamination and Absence of Escherichia coli O157:H7 on Romaine Lettuce from Retail Stores in the Upper Midwest.

Science.gov (United States)

Greve, Josephine D; Zietlow, Mark S; Miller, Kevin M; Ellingson, Jay L E

2015-09-01

A total of 720 whole, romaine lettuce heads were purchased from retail locations in the Upper Midwest and assessed for coliform and Escherichia coli contamination and for the presence of E. coli O157:H7. During a 16-month period (August 2010 through December 2011), coliform and E. coli counts were enumerated on Petrifilm, and the presence of E. coli O157:H7 and the virulence gene eae was evaluated by real-time PCR (qPCR). Over half (400 of 720) of the lettuce samples were processed with an immunomagnetic separation step before the qPCR assay. All retail lettuce samples were negative for E. coli O157:H7 when tested with the R.A.P.I.D. LT qPCR targeting a region of the O-antigen, and only two (0.28%) were positive for the eae gene when tested with LightCycler qPCR. On Petrifilm, coliform counts of most lettuce samples (96.4%) were between lettuce samples (98.2%) were lettuce heads. These results contribute to the limited recorded data and understanding of microbial contamination of whole romaine lettuce heads purchased from retail locations, specifically revealing the absence of E. coli O157:H7 and low levels of contamination with coliforms and other E. coli strains.

7 CFR 319.56-24 - Lettuce and peppers from Israel.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Lettuce and peppers from Israel. 319.56-24 Section 319... Lettuce and peppers from Israel. (a) Lettuce may be imported into the United States from Israel without... protected with sticky traps and prophylactic sprays approved for the crop by Israel; (v) The lettuce must be...

Principal Component Analysis of Some Quantitative and Qualitative Traits in Iranian Spinach Landraces

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Mohebodini Mehdi

2017-08-01

Full Text Available Landraces of spinach in Iran have not been sufficiently characterised for their morpho-agronomic traits. Such characterisation would be helpful in the development of new genetically improved cultivars. In this study 54 spinach accessions collected from the major spinach growing areas of Iran were evaluated to determine their phenotypic diversity profile of spinach genotypes on the basis of 10 quantitative and 9 qualitative morpho-agronomic traits. High coefficients of variation were recorded in some quantitative traits (dry yield and leaf area and all of the qualitative traits. Using principal component analysis, the first four principal components with eigen-values more than 1 contributed 87% of the variability among accessions for quantitative traits, whereas the first four principal components with eigen-values more than 0.8 contributed 79% of the variability among accessions for qualitative traits. The most important relations observed on the first two principal components were a strong positive association between leaf width and petiole length; between leaf length and leaf numbers in flowering; and among fresh yield, dry yield and petiole diameter; a near zero correlation between days to flowering with leaf width and petiole length. Prickly seeds, high percentage of female plants, smooth leaf texture, high numbers of leaves at flowering, greygreen leaves, erect petiole attitude and long petiole length are important characters for spinach breeding programmes.

Sensory shelf life estimation of minimally processed lettuce considering two stages of consumers' decision-making process.

Science.gov (United States)

Ares, Gastón; Giménez, Ana; Gámbaro, Adriana

2008-01-01

The aim of the present work was to study the influence of context, particularly the stage of the decision-making process (purchase vs consumption stage), on sensory shelf life of minimally processed lettuce. Leaves of butterhead lettuce were placed in common polypropylene bags and stored at 5, 10 and 15 degrees C. Periodically, a panel of six assessors evaluated the appearance of the samples, and a panel of 40 consumers evaluated their appearance and answered "yes" or "no" to the questions: "Imagine you are in a supermarket, you want to buy a minimally processed lettuce, and you find a package of lettuce with leaves like this, would you normally buy it?" and "Imagine you have this leaf of lettuce stored in your refrigerator, would you normally consume it?". Survival analysis was used to calculate the shelf lives of minimally processed lettuce, considering both decision-making stages. Shelf lives estimated considering rejection to purchase were significantly lower than those estimated considering rejection to consume. Therefore, in order to be conservative and assure the products' quality, shelf life should be estimated considering consumers' rejection to purchase instead of rejection to consume, as traditionally has been done. On the other hand, results from logistic regressions of consumers' rejection percentage as a function of the evaluated appearance attributes suggested that consumers considered them differently while deciding whether to purchase or to consume minimally processed lettuce.

Water lettuce

African Journals Online (AJOL)

Nutritive values, Mineral and Antioxidant properties of Pistia stratiotes (Water lettuce). 1R .S.U. Wasagu ... The use of plants as medicines predates written human history and some of ... used to maintain health, as well as to prevent, diagnose ...

Jatropha press cake as organic fertilizer in lettuce cultivation

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José R. Mantovani

Full Text Available ABSTRACT In biodiesel production, vegetable press cake is obtained as waste, and a suitable destination for jatropha press cake would be the use in agriculture as organic fertilizer. This study aimed to evaluate the effect of jatropha press cake on soil fertility attributes and on lettuce production and accumulation of nutrients in the shoots. The experiment was conducted in pots in a greenhouse, in a randomized block design with eight treatments and five replicates. The treatments consisted of doses of jatropha press cake equivalent to 0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 and 32.0 t ha-1. Portions of 5.5 dm3 of soil received limestone, phosphate fertilizer and the doses of jatropha press cake, and remained incubated for 30 days. After incubation, soil samples were collected, each pot received one lettuce seedling and the experiment was carried out for 45 days. The organic fertilization with jatropha press cake increased the contents of nutrients in the soil, especially K+, but caused increment in soil acidity and electrical conductivity. The use of jatropha press cake as organic fertilizer decreased lettuce production and accumulation of nutrients in the shoots.

Physiological and health quality of commercial lettuce and cabbage seed

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Cleyton Teles Contreiras Paiva

2016-08-01

Full Text Available Physiological and sanitary seed quality is essential for rapid and uniform crop establishment at field, a factor which contributes to vegetable crop production success. The aim was to evaluate physiological and sanitary quality of lettuce and cabbage seeds coming three lots acquired in trade. Physiological quality was determined by means of germination test and index of speed germination. Health status was assessed through sanity test in Petri dishes containing BDA medium. The experimental design was completely randomized with four replications and the averages of each lot compared among themselves by Tukey test (5%. No statistical analyzes were performed to health test and samples were evaluated for presence of microorganisms on the plates. Aspergillus spp., Rhizopus spp., cocci and bacillus are associated with lettuce seeds, and Aspergillus spp., cocci and bacillus are associated with cabbage seeds, but this association can not interfere with germination performance at laboratory. Information about germination contained in the package do not always coincide with those examined in situ. Lettuce and cabbage seeds are being marketed carrying pathogens.

Virus diseases in lettuce in the Mediterranean basin.

Science.gov (United States)

Moreno, Aranzazu; Fereres, Alberto

2012-01-01

Lettuce is frequently attacked by several viruses causing disease epidemics and considerable yield losses along the Mediterranean basin. Aphids are key pests and the major vectors of plant viruses in lettuce fields. Lettuce mosaic virus (LMV) is probably the most important because it is seed-transmitted in addition to be transmissible by many aphid species that alight on the crop. Tomato spotted wilt virus (TSWV) is another virus that causes severe damage since the introduction of its major vector, the thrips Frankliniella occidentalis. In regions with heavy and humid soils, Lettuce Mirafiori big-vein virus (LMBVV) can also produce major yield losses. Copyright © 2012 Elsevier Inc. All rights reserved.

Starch accumulation during hydroponic growth of spinach and basil plants under carbon dioxide enrichment

Energy Technology Data Exchange (ETDEWEB)

Holbrook, G P; Hansen, J; Wallick, K; Zinnen, T M [North Illinois University, de Kalb, IL (USA). Dept. of Biological Sciences

1993-04-01

The effects of CO[sub 2] enrichment, photoperiod duration, and inorganic phosphate levels on growth and starch accumulaton by spinach and basil plants were studied in a commercial hydroponic facility. During a 3-week growth period, both species exhibited increased whole-plant fresh weight as a result of an increase in atmospheric CO[sub 2] concentration from 400 to 1500 mul/1. However, basil leaves exhibited a 1.5- to 2-fold greater increase in specific leaf weight (SLW), and accumulated starch to much greater levels than did leaves of spinach. At 1500 mul CO[sub 2]/1, starch accounted for up to 38% of SLW with basil compared to [lt] 10% of SLW with spinach. The maximum ratio of starch/chlorophyll was 55.0 in basil leaves vs 8.0 in spinach leaves. High ratio values were associated with the appearance of chlorotic symptoms in leaves of basil grown under CO[sub 2] enrichment, whereas spinach did not exhibit chlorosis. Increasing inorganic phosphate concentrations from 0.7 to 1.8 mM in the hydroponic medium did not appreciably affect leaf starch accumulation in either species. Starch accumulation in basil leaves was not consistently related to the duration of the photoperiod. However, photoperiod-induced changes in leaf starch levels were much greater in basil than spinach. The results clearly indicate that different horticultural crops can show diverse responses to CO[sub 2] enrichment, and thus highlight the need to develop individual growth strategies to optimize production quality of each species.

Influence of Gamma Irradiation on Biogenic Amine Contents and Pathogenic Bacteria in Spinach

International Nuclear Information System (INIS)

Ali, H.A.S.

2015-01-01

This study was carried out to evaluate the effect of gamma irradiation at doses 1, 2, 4 and 6 kGy as compared with blanching at 95°C/3 min on biogenic amine contents and pathogenic bacteria in spinach leaves (Spinacia oleracea L.). The results indicated that tryptamine and β- phenylethylamine were not detected while histamine was the major amine detected at concentration of 12.55 mg/100g of wet weight. Blanching at 95°C/3 min significantly reduced the content of histamine, putrescine and tyramine in spinach while significantly increased the content of cadaverine. Gamma irradiation at different doses significantly reduced the contents of histamine and tyramine while significantly increased the content of cadaverine. However, putrescine content was increased significantly after subjected to doses 1 and 2 kGy while the doses 4 and 6 kGy significantly reduced it. Regarding to microbiological analysis in spinach, it could be noticed that total bacterial count, Enterobacteriaceae, coliform group, yeast, mould, Staphylococcus aureus and Salmonella spp. in fresh spinach were 5.97, 4.40, 2.53, 2.11, 1.40, 1.48 and 1.18 log cfu/g, respectively. Changes in microbiological characters (cfu/g) in spinach by different gamma irradiation doses and blanching were also followed. It could be noticed that the total bacterial count, Enterobacteriaceae, coliform group, yeast, mould, Staphylococcus aureus and Salmonella spp. were significantly decreased after treatment with blanching and gamma irradiation and these microorganisms were not detected after being subjected to 4 and 6 kGy. It could be concluded that blanching at 95°C/3 min or gamma irradiation at dose 2 kGy can be used to control the pathogenic bacteria and reduce biogenic amine (histamine, putrescine and tyramine) in spinach

Extraction of functional ingredients from spinach (Spinacia oleracea L.) using liquid solvent and supercritical CO₂ extraction.

Science.gov (United States)

Jaime, Laura; Vázquez, Erika; Fornari, Tiziana; López-Hazas, María del Carmen; García-Risco, Mónica R; Santoyo, Susana; Reglero, Guillermo

2015-03-15

In this work three different techniques were applied to extract dry leaves of spinach (Spinacia oleracea): solid-liquid extraction (SLE), pressurised liquid extraction (PLE) and supercritical fluid extraction (SFE) to investigate the influence of extraction solvent and technique on extracts composition and antioxidant activity. Moreover, the influence of carotenoids and phenolic compounds on the antioxidant and anti-inflammatory activities of spinach extracts was also studied. The higher concentrations of carotenoids and the lower content of phenolic compounds were observed in the supercritical CO₂ extracts; whereas water and/or ethanol PLE extracts presented low amounts of carotenoids and the higher concentrations of phenolic compounds. PLE extract with the highest content of phenolic compounds showed the highest antioxidant activity, although SFE carotenoid rich extract also showed a high antioxidant activity. Moreover, both extracts presented an important anti-inflammatory activity. PLE seems to be a good technique for the extraction of antioxidant and anti-inflammatory compounds from spinach leaves. Moreover, spinach phenolic compounds and carotenoids present a high antioxidant activity, whereas spinach carotenoids seem to show a higher anti-inflammatory activity than phenolic compounds. It is worth noting that of our knowledge this is the first time the anti-inflammatory activity of lipophilic extracts from spinach leaves is reported. © 2014 Society of Chemical Industry.

Detection of Lettuce Discoloration Using Hyperspectral Reflectance Imaging.

Science.gov (United States)

Mo, Changyeun; Kim, Giyoung; Lim, Jongguk; Kim, Moon S; Cho, Hyunjeong; Cho, Byoung-Kwan

2015-11-20

Rapid visible/near-infrared (VNIR) hyperspectral imaging methods, employing both a single waveband algorithm and multi-spectral algorithms, were developed in order to discrimination between sound and discolored lettuce. Reflectance spectra for sound and discolored lettuce surfaces were extracted from hyperspectral reflectance images obtained in the 400-1000 nm wavelength range. The optimal wavebands for discriminating between discolored and sound lettuce surfaces were determined using one-way analysis of variance. Multi-spectral imaging algorithms developed using ratio and subtraction functions resulted in enhanced classification accuracy of above 99.9% for discolored and sound areas on both adaxial and abaxial lettuce surfaces. Ratio imaging (RI) and subtraction imaging (SI) algorithms at wavelengths of 552/701 nm and 557-701 nm, respectively, exhibited better classification performances compared to results obtained for all possible two-waveband combinations. These results suggest that hyperspectral reflectance imaging techniques can potentially be used to discriminate between discolored and sound fresh-cut lettuce.

STATISTIC MODELING OF DRYING KINETHIC OF SPINACH LEAVES USING MICROWAVE AND HOT AIR METHODS

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Mojtaba Nouri

2015-06-01

Full Text Available The target of this study was to model of spinach leaves drying using microwave and hot air dryer. This test performed in combination treatment of temperatures (50°C, 60°C, and 70°C and microwave (90, 180, 360, 600 and 900w in 3 replications. Sample moisture measured within drying. All the results were fitted and analyzed with 8 mathematical models base on 3 parameters including determination (R2, Chi square(X2, root mean square errors(RSME. Results also revealed that temperature and microwave power effectively reduce the drying time when increase. Drying occurs in degrading stage; moreover the comparison of results exhibited that Page and Two sentences models were fitted appropriately to estimate moisture changing and drying description. Regarding all the results, it is cleared that microwave method is an appropriate method in spinach drying as a result of reducing drying temperature and its high efficiency.

Residues of maneb in potatoes and lettuce and their persistence during cooking, washing and uv exposition

International Nuclear Information System (INIS)

Bennaceur, M.; Sennaoui, Z.; Zennouche, B.; Hylin, J.W.

1992-01-01

Lettuce plants were treated each with 0,186 mg of 14C maneb and 1,86 mg unlabelled maneb. The plants were analyzed 30 days later and subjected to washing. Washing eliminates 17,46% of total 14C maneb applied. No Etu was observed in water.Washing and baking cause a significant decrease of EBDC in potatoes samples and the UV exposition involves a decrease of the fungicide and a formation of Etu. On the other hand 54 % and 38% of lettuce and potatoe samples analyzed by CS2 method exceed the authorized norms

Effects of substrate type on plant growth and nitrogen and nitrate concentration in spinach

Science.gov (United States)

The effects of three commercial substrates (a mixture of forest residues, composted grape husks, and white peat; black peat; and coir) on plant growth and nitrogen (N) and nitrate (NO3) concentration and content were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were trans...

Endophytic fungi occurring in fennel, lettuce, chicory, and celery--commercial crops in southern Italy.

Science.gov (United States)

D'Amico, Margherita; Frisullo, Salvatore; Cirulli, Matteo

2008-01-01

The occurrence of endophytic fungi in fennel, lettuce, chicory, and celery crops was investigated in southern Italy. A total of 186 symptomless plants was randomly collected and sampled at the stage of commercial ripeness. Fungal species of Acremonium, Alternaria, Fusarium, and Plectosporium were detected in all four crops; Plectosporium tabacinum was the most common in all crop species and surveyed sites. The effect of eight endophytic isolates (five belonging to Plectosporium tabacinum and three to three species of Acremonium) inoculated on lettuce plants grown in gnotobiosis was assessed by recording plant height, root length and dry weight, collar diameter, root necrosis, and leaf yellowing. P. tabacinum and three species of Acremonium, inoculated on gnotobiotically grown lettuce plants, showed pathogenic activity that varied with the fungal isolate. Lettuce plants inoculated with the isolates Ak of Acremonium kiliense, Ac of Acremonium cucurbitacearum, and P35 of P. tabacinum showed an increased root growth, compared to the non-inoculated control. The high frequency of P. tabacinum isolation recorded in lettuce plants collected in Bari and Metaponto, and in fennel plants from Foggia agricultural districts, suggests a relationship not only between a crop species and P. tabacinum, but also between the occurrence of the endophyte and the crop rotation history of the soil.

Class II recombinant phosphoribosyl diphosphate synthase from spinach

DEFF Research Database (Denmark)

Krath, B N; Hove-Jensen, B

2001-01-01

to other PRPP synthases the activity of spinach PRPP synthase isozyme 3 is independent of P(i), and the enzyme is inhibited by ribonucleoside diphosphates in a purely competitive manner, which indicates a lack of allosteric inhibition by these compounds. In addition spinach PRPP synthase isozyme 3 shows...... an unusual low specificity toward diphosphoryl donors by accepting dATP, GTP, CTP, and UTP in addition to ATP. The kinetic mechanism of the enzyme is an ordered steady state Bi Bi mechanism with K(ATP) and K(Rib-5-P) values of 170 and 110 micrometer, respectively, and a V(max) value of 13.1 micromol (min x...... mg of protein)(-1). The enzyme has an absolute requirement for magnesium ions, and maximal activity is obtained at 40 degrees C at pH 7.6....

Effect of dim light irradiation on preservation of fresh lettuce

International Nuclear Information System (INIS)

Harada, F.; Uchino, T.; Akimoto, K.; Hu, W.

2001-01-01

In order to preserve fresh lettuce, the dim light irradiation storage was investigated. Lettuce (Lactuca sativa L.) stored for about 120 hours at 5 or 20 deg C under continuous illumination at 0 (darkness), 1.6, 3.4, 6.5, 13 or 19.7 micro mol/m**-2/s**-1 photosynthetic photon flux. The light compensation point was about 3.4 micro mol/m**-2/s**-1 at 5 deg C, about 19.7 micro mol/m**-2/s**-1 at 20 deg C. Fresh weight of lettuce decreased by promotion of transpiration caused by the dim light. Accordingly the root of lettuce should not be removed, so as to up-take water. The optimum dim light irradiation preserved the chlorophyll content in lettuce leaf or increased it. Therefore it appeared that the dim light irradiation was effective for the fresh lettuce preservation

Microbiological quality of organic vegetables produced in soil treated with different types of manure and mineral fertilizer Qualidade microbiológica de vegetais orgânicos produzidos em solo tratado com diferentes tipos de esterco e fertilizante mineral

Directory of Open Access Journals (Sweden)

Débora Cabral Machado

2006-12-01

Full Text Available An attempt was made to evaluate microbiological quality of horticultural crops grown organically. Three species of vegetables were used, lettuce (Lactuva sativa, radish (Raphanus sativus and spinach (Tetragonia expansa, grown organically, in fertile soil. Six different treatments were applied: mineral fertilizer, chicken, cow, and pig manure, chicken litter and cow manure, in association with a liquid foliar biofertilizer. These crops were handled according to correct agronomic practices for growing crops organically for commercial purposes. Samples were examined for the Most Probable Number (MPN/g/mL of total and fecal coliforms and to detect the presence of Escherichia coli and Salmonella spp. All analyzed samples were considered acceptable for consumption, as Salmonella spp. was not detected. However, 63.3%, 50.0%, and 23.3% of the samples of lettuce, radish and spinach, respectively, contained >10² total coliforms/g of product. None of the samples of spinach or radish presented >10² fecal coliforms/g, and only 6.6% of lettuce samples contained >10² fecal coliforms/g. The presence of E. coli was confirmed in one sample of spinach, cultivated with cow manure.O objetivo do presente trabalho foi avaliar a qualidade microbiológica de hortaliças orgânicas produzidas sob diferentes condições. Três espécies de vegetais, alface (Lactuva sativa, rabanete (Raphanus sativus e espinafre (Tetragonia expansa, foram cultivadas no sistema orgânico, em solo fertilizado com seis tratamentos diferentes: adubo mineral, estercos de galinha, bovino e suíno, cama de frango e esterco bovino associado com biofertilizante líquido de aplicação foliar. O cultivo das hortaliças foi feito de acordo com as práticas agronômicas recomendadas para o sistema orgânico em escala comercial. Das hortaliças cultivadas, foram coletadas amostras para a determinação do Número Mais Provável de coliformes totais e termotolerantes e detecção da presença de

Effects of spinach nitrate on insulin resistance, endothelial dysfunction markers and inflammation in mice with high-fat and high-fructose consumption

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Ting Li

2016-09-01

Full Text Available Background: Insulin resistance, which is associated with an increased risk of cardiovascular morbidity and mortality, has become a leading nutrition problem. Inorganic nitrate enriched in spinach has been demonstrated to reverse the pathological features of insulin resistance and endothelial dysfunction. However, the effects of a direct intake of nitrate-enriched spinach on insulin resistance and endothelial dysfunction have not been studied. Objective: To investigate the effects of spinach nitrate on insulin resistance, lipid metabolism, endothelial function, and inflammation in mice fed with a high-fat and high-fructose diet. Design: A diet intervention of spinach with or without nitrate was performed in mice. A high-fat and high-fructose diet was used to cause insulin resistance, endothelial dysfunction, and inflammation in mice. The impacts of spinach nitrate on lipid profile, insulin resistance, markers of endothelial function, and inflammation were determined in mice. Results: Spinach nitrate improved the vascular endothelial function of the mice with high-fat and high-fructose consumption, as evidenced by the elevated plasma nitrite level, increased serum nitric oxide (NO level and decreased serum ET-1 level after spinach nitrate intervention. Spinach nitrate also reduced serum triglycerides, total cholesterol, and low-density lipoprotein-cholesterol levels and elevated serum high-density lipoprotein-cholesterol levels in the mice fed with a high-fat and high-fructose diet. Mice receiving spinach with 60 mg/kg of nitrate (1.02±0.34 showed a significantly low homeostasis model assessment-insulin resistance index as compared with the model mice (2.05±0.58, which is indicating that spinach nitrate could effectively improve the insulin resistance. In addition, spinach nitrate remarkably decreased the elevated serum C-reactive protein, tumor necrosis factor α, and interleukin-6 levels induced by a high-fat and high-fructose diet

Possible Internalization of an Enterovirus in Hydroponically Grown Lettuce

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Annalaura Carducci

2015-07-01

Full Text Available Several studies have shown that enteric viruses can be transferred onto the surface of vegetables and fruits through spray irrigation, but, recently, reports have suggested viral contamination of vegetables sub-irrigated with reused wastewater. Hydroponic cultures, used to grow ready to eat fresh lettuce, have also been used to study the possibility of viral absorption through roots. This study was conducted to assess a possible risk of viral contamination in lettuce from contaminated water. The leaves of lettuce plants grown in hydroponic cultures where the roots were exposed to water containing Coxsakievirus B2, were analysed for evidence of the virus. The plants and water were sampled at different times and virus was measured using quantitative RT-PCR and infectivity assay. In leaf samples, the lowest observed infective data were lower than the qRT-PCR detection limits, suggesting that free viral RNA or damaged viruses are eliminated rapidly while infectious particles remain stable for a longer time. The obtained data revealed that the leaves were contaminated at a water concentration of 4.11 ± 1 Log Most Probable Number/L (8.03 ± 1 Log GC/L a concentration observed in contaminated untreated water of wastewater treatment plants. However, the absorption dynamics and whether the virus is inactive in the leaves still remains to be clarified. Nevertheless, this work has practical implications for risk management in using reclaimed water for agricultural use; when irrigated vegetables are destined for raw consumption, virological contamination in water sources should be evaluated.

Possible Internalization of an Enterovirus in Hydroponically Grown Lettuce.

Science.gov (United States)

Carducci, Annalaura; Caponi, Elisa; Ciurli, Adriana; Verani, Marco

2015-07-17

Several studies have shown that enteric viruses can be transferred onto the surface of vegetables and fruits through spray irrigation, but, recently, reports have suggested viral contamination of vegetables sub-irrigated with reused wastewater. Hydroponic cultures, used to grow ready to eat fresh lettuce, have also been used to study the possibility of viral absorption through roots. This study was conducted to assess a possible risk of viral contamination in lettuce from contaminated water. The leaves of lettuce plants grown in hydroponic cultures where the roots were exposed to water containing Coxsakievirus B2, were analysed for evidence of the virus. The plants and water were sampled at different times and virus was measured using quantitative RT-PCR and infectivity assay. In leaf samples, the lowest observed infective data were lower than the qRT-PCR detection limits, suggesting that free viral RNA or damaged viruses are eliminated rapidly while infectious particles remain stable for a longer time. The obtained data revealed that the leaves were contaminated at a water concentration of 4.11 ± 1 Log Most Probable Number/L (8.03 ± 1 Log GC/L) a concentration observed in contaminated untreated water of wastewater treatment plants. However, the absorption dynamics and whether the virus is inactive in the leaves still remains to be clarified. Nevertheless, this work has practical implications for risk management in using reclaimed water for agricultural use; when irrigated vegetables are destined for raw consumption, virological contamination in water sources should be evaluated.

Proteomic analysis of lettuce seed germination and thermoinhibition by sampling of individual seeds at germination and removal of storage proteins by polyethylene glycol fractionation.

Science.gov (United States)

Wang, Wei-Qing; Song, Bin-Yan; Deng, Zhi-Jun; Wang, Yue; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

2015-04-01

Germination and thermoinhibition in lettuce (Lactuca sativa 'Jianyexianfeng No. 1') seeds were investigated by a proteomic comparison among dry seeds, germinated seeds at 15°C, at 15°C after imbibition at 25°C for 48 h, or at 25°C in KNO3 (all sampled individually at germination), and ungerminated seeds at 25°C, a thermoinhibitory temperature. Before two-dimensional gel electrophoresis analysis, storage proteins (greater than 50% of total extractable protein) were removed by polyethylene glycol precipitation, which significantly improved the detection of less abundant proteins on two-dimensional gels. A total of 108 protein spots were identified to change more than 2-fold (Pseeds than in ungerminated 25°C seeds. Gene expression of 12 of those proteins correlated well with the protein accumulation. Methionine metabolism, ethylene production, lipid mobilization, cell elongation, and detoxification of aldehydes were revealed to be potentially related to lettuce seed germination and thermoinhibition. Accumulation of three proteins and expression of five genes participating in the mevalonate (MVA) pathway of isoprenoid biosynthesis correlated positively with seed germinability. Inhibition of this pathway by lovastatin delayed seed germination and increased the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination and thermoinhibition. © 2015 American Society of Plant Biologists. All Rights Reserved.

Genes up-regulated during red coloration in UV-B irradiated lettuce leaves.

Science.gov (United States)

Park, Jong-Sug; Choung, Myoung-Gun; Kim, Jung-Bong; Hahn, Bum-Soo; Kim, Jong-Bum; Bae, Shin-Chul; Roh, Kyung-Hee; Kim, Yong-Hwan; Cheon, Choong-Ill; Sung, Mi-Kyung; Cho, Kang-Jin

2007-04-01

Molecular analysis of gene expression differences between green and red lettuce leaves was performed using the SSH method. BlastX comparisons of subtractive expressed sequence tags (ESTs) indicated that 7.6% of clones encoded enzymes involved in secondary metabolism. Such clones had a particularly high abundance of flavonoid-metabolism proteins (6.5%). Following SSH, 566 clones were rescreened for differential gene expression using dot-blot hybridization. Of these, 53 were found to overexpressed during red coloration. The up-regulated expression of six genes was confirmed by Northern blot analyses. The expression of chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), and dihydroflavonol 4-reductase (DFR) genes showed a positive correlation with anthocyanin accumulation in UV-B-irradiated lettuce leaves; flavonoid 3',5'-hydroxylase (F3',5'H) and anthocyanidin synthase (ANS) were expressed continuously in both samples. These results indicated that the genes CHS, F3H, and DFR coincided with increases in anthocyanin accumulation during the red coloration of lettuce leaves. This study show a relationship between red coloration and the expression of up-regulated genes in lettuce. The subtractive cDNA library and EST database described in this study represent a valuable resource for further research for secondary metabolism in the vegetable crops.

On the structure of the spinach chloroplast

NARCIS (Netherlands)

Thomas, J.B.; Bustraan, M.; Paris, C.H.

1952-01-01

The structure of spinach chloroplasts was investigated with the aid of the electron microscope. It has been established that: 1. 1. the outer membrane of the chloroplasts is composed of both proteins and lipoids. 2. 2. the stroma is also built up by these components. 3. 3. within the

Genetic characterization of resistance to Sclerotinia in lettuce cultivar Eruption

Science.gov (United States)

Lettuce drop caused by the fungal pathogens Sclerotinia minor and S. sclerotiorum is a serious disease of lettuce. The use of genetic resistance as part of an integrated lettuce drop management strategy should have a significant economic advantage in mitigating yield loss. Sclerotinia resistance is ...

Reduction of cadmium uptake in spinach (Spinacia oleracea L.) by soil amendment with animal waste compost

Energy Technology Data Exchange (ETDEWEB)

Sato, Atsushi, E-mail: asatou@ari.pref.niigata.jp [Niigata Horticultural Research Center, 177 Mano, Seiro, Niigata 957-0111 (Japan); Takeda, Hiroyuki [Niigata Horticultural Research Center, 177 Mano, Seiro, Niigata 957-0111 (Japan); Oyanagi, Wataru [Niigata Livestock Research Center, 178 Tanahire, Sanjo, Niigata 955-0143 (Japan); Nishihara, Eiji [Tottori University, 4-101 Koyama-Minami, Tottori 680-8550 (Japan); Murakami, Masaharu [Soil Environment Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604 (Japan)

2010-09-15

A field experiment was conducted to evaluate the efficacy of animal waste compost (AWC) in reducing Cd uptake by spinach (Spinacia oleracea L.). Spinach was grown in a field that had been treated by having cattle, swine, or poultry waste compost incorporated into the soil before each crop throughout 4 years of rotational vegetable production. Cadmium concentration was 34-38% lower in spinach harvested from the AWC-treated soils than in the chemical fertilizer-treated soil. Although the repeated application of swine and poultry compost caused significant P accumulation in the cropped soils, that of cattle compost did not. These results indicate that cattle compost with high affinity for Cd and low P content should be the preferred soil amendment when used to reduce Cd uptake by spinach.

Reduction of cadmium uptake in spinach (Spinacia oleracea L.) by soil amendment with animal waste compost

International Nuclear Information System (INIS)

Sato, Atsushi; Takeda, Hiroyuki; Oyanagi, Wataru; Nishihara, Eiji; Murakami, Masaharu

2010-01-01

A field experiment was conducted to evaluate the efficacy of animal waste compost (AWC) in reducing Cd uptake by spinach (Spinacia oleracea L.). Spinach was grown in a field that had been treated by having cattle, swine, or poultry waste compost incorporated into the soil before each crop throughout 4 years of rotational vegetable production. Cadmium concentration was 34-38% lower in spinach harvested from the AWC-treated soils than in the chemical fertilizer-treated soil. Although the repeated application of swine and poultry compost caused significant P accumulation in the cropped soils, that of cattle compost did not. These results indicate that cattle compost with high affinity for Cd and low P content should be the preferred soil amendment when used to reduce Cd uptake by spinach.

An unusual spliced variant of DELLA protein, a negative regulator of gibberellin signaling, in lettuce.

Science.gov (United States)

Sawada, Yoshiaki; Umetsu, Asami; Komatsu, Yuki; Kitamura, Jun; Suzuki, Hiroyuki; Asami, Tadao; Fukuda, Machiko; Honda, Ichiro; Mitsuhashi, Wataru; Nakajima, Masatoshi; Toyomasu, Tomonobu

2012-01-01

DELLA proteins are negative regulators of the signaling of gibberellin (GA), a phytohormone regulating plant growth. DELLA degradation is triggered by its interaction with GID1, a soluble GA receptor, in the presence of bioactive GA. We isolated cDNA from a spliced variant of LsDELLA1 mRNA in lettuce, and named it LsDELLA1sv. It was deduced that LsDELLA1sv encodes truncated LsDELLA1, which has DELLA and VHYNP motifs at the N terminus but lacks part of the C-terminal GRAS domain. The recombinant LsDELLA1sv protein interacted with both Arabidopsis GID1 and lettuce GID1s in the presence of GA. A yeast two-hybrid assay suggested that LsDELLA1sv interacted with LsDELLA1. The ratio of LsDELLA1sv to LsDELLA1 transcripts was higher in flower samples at the late reproductive stage and seed samples (dry seeds and imbibed seeds) than in the other organ samples examined. This study suggests that LsDELLA1sv is a possible modulator of GA signaling in lettuce.

Comparative Study of Betacyanin Profile and Antimicrobial Activity of Red Pitahaya (Hylocereus polyrhizus) and Red Spinach (Amaranthus dubius).

Science.gov (United States)

Yong, Yi Yi; Dykes, Gary; Lee, Sui Mae; Choo, Wee Sim

2017-03-01

Betacyanins are reddish to violet pigments that can be found in red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius). This study investigated the impact of sub-fractionation (solvent partitioning) on betacyanin content in both plants. Characterization of betacyanins and evaluation of their antimicrobial activities were also carried out. Betanin was found in both plants. In addition, isobetanin, phyllocactin and hylocerenin were found in red pitahaya whereas amaranthine and decarboxy-amaranthine were found in red spinach. Sub-fractionated red pitahaya and red spinach had 23.5 and 121.5 % more betacyanin content, respectively, than those without sub-fractionation. Sub-fractionation increased the betanin and decarboxy-amaranthine content in red pitahaya and red spinach, respectively. The betacyanin fraction from red spinach (minimum inhibitory concentration [MIC] values: 0.78-3.13 mg/mL) demonstrated a better antimicrobial activity profile than that of red pitahaya (MIC values: 3.13-6.25 mg/mL) against nine Gram-positive bacterial strains. Similarly, the red spinach fraction (MIC values: 1.56-3.13 mg/mL) was more active than the red pitahaya fraction (MIC values: 3.13-6.25 mg/mL) against five Gram-negative bacterial strains. This could be because of a higher amount of betacyanin, particularly amaranthine in the red spinach.

Microbiological evaluation of ready-to-eat iceberg lettuce during shelf-life and effectiveness of household washing methods

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Daniela Bencardino

2018-04-01

Full Text Available The aim of this study was to assess the microbiological quality of ready-to-eat (RTE iceberg lettuce. Our investigation was based on the consumption tendency of university students considered a target market for this product. A total of 78 RTE samples were collected from chain supermarkets and analysed for the enumeration of aerobic mesophilic count (AMC, Escherichia coli and the detection of Salmonella spp. and Listeria monocytogenes. All samples were negative for the presence of pathogens. The mean value of AMC at the beginning, in the middle and after the expiration date was: 6.88, 8.51 and 8.72 log CFU g-1, respectively. The same investigation was performed on 12 samples of fresh iceberg lettuce samples. No pathogens were found and the mean value of AMC was lower than the RTE category (5.73 log CFU g-1; P<0.05. The effectiveness of 5 washing methods was determined on 15 samples of both fresh and RTE iceberg lettuce. Samples were washed for 15’ and 30’ in tap water (500 mL, tap water with NaCl (4 g/500 mL, tap water with bicarbonate (8 g/500 mL, tap water with vinegar (10 mL/500 mL and tap water with chlorine-based disinfectant (10 mL/500 mL. A significant bacterial load reduction was recorded for vinegar and disinfectant after 30’ and 15’, respectively. Overall, these results showed that RTE iceberg lettuce is more contaminated than the fresh product. Also, the consumption in the first few days of packaging and after washing with disinfectants reduces the risk for health consumers.

Genetics of resistance against lettuce downy mildew

Science.gov (United States)

Lettuce (Lactuca sativa) is one of the most valuable vegetable crops in the U.S. Downy mildew (DM), caused by Bremia lactucae, is the most important foliar disease of lettuce worldwide, which decreases the quality of the marketable portion of the crop. The use of resistant varieties carrying dominan...

Vegetable Production in an Integrated Aquaponic System with Stellate Sturgeon and Spinach – Matador variety

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Stefan Mihai Petrea

2014-05-01

Full Text Available This study aims to reveal the performances parameters, both in terms of quantity and quality, for spinach (Spinacia oleracea - Matador variety, growth in an aquaponic integrated system, along with stellate sturgeons (A. stellatus under three crops densities (V1 - 59 crops/m2, V2 – 48 crops/m2 and V3 – 39 crops/m2, by using hydroton as growing substrate, under a continuous flow hydraulic regime. The experiment was run in triplicate for each one of the three variants. The water quality was monitored and a series of growth parameters were determined, as follows: leaf area index (LAI, relative growth rate (RGR, average net assimilation rate (NAR, mean leaf area ratio (LAR and crop growth rate (CGR. Also the concentration of chlorophyll a, b, carotenoids, ash and dry matter for spinach leaf, from each of the three experimental variants was determined and compared with the one of marketable spinach, growth conventional, in soil. It can be concluded that statistical significant differences (p<0.05 were recorded in terms of growth performance and crops quality, between the experimental variants. Also the quality of spinach grown in aquaponic conditions, by using effluent derived from stellate sturgeon intensive aquaculture is similar to that of the marketable spinach, growth conventional.

Agricultural and Management Practices and Bacterial Contamination in Greenhouse versus Open Field Lettuce Production

Science.gov (United States)

Holvoet, Kevin; Sampers, Imca; Seynnaeve, Marleen; Jacxsens, Liesbeth; Uyttendaele, Mieke

2014-01-01

The aim of this study was to gain insight into potential differences in risk factors for microbial contamination in greenhouse versus open field lettuce production. Information was collected on sources, testing, and monitoring and if applicable, treatment of irrigation and harvest rinsing water. These data were combined with results of analysis on the levels of Escherichia coli as a fecal indicator organism and the presence of enteric bacterial pathogens on both lettuce crops and environmental samples. Enterohemorragic Escherichia coli (EHEC) PCR signals (vt1 or vt2 positive and eae positive), Campylobacter spp., and Salmonella spp. isolates were more often obtained from irrigation water sampled from open field farms (21/45, 46.7%) versus from greenhouse production (9/75, 12.0%). The open field production was shown to be more prone to fecal contamination as the number of lettuce samples and irrigation water with elevated E. coli was significantly higher. Farmers comply with generic guidelines on good agricultural practices available at the national level, but monitoring of microbial quality, and if applicable appropriateness of water treatment, or water used for irrigation or at harvest is restricted. These results indicate the need for further elaboration of specific guidelines and control measures for leafy greens with regard to microbial hazards. PMID:25546272

Effect of hexane extract of spinach in the removal of arsenic from rat

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Badar Uddin Umar

2007-03-01

Full Text Available Extensive search is going on for a cheap, easily available and effective remedy of chronic arsenic poisoning. The present study was designed to find the effects of hexane extract of spinach in the removal of arsenic from arsenic treated rat. Rats were fed arsenic trioxide through Ryle’s tube for one month then they were fed on hexane extract (1-4% of spinach for another one month. Hexane extract of spinach decreased accumulated arsenic from rat liver, spleen, kidney, intestine, lungs and skin significantly. Besides, it reduced the oxidative stress caused by arsenic which was evident by decreased levels of malondialdehye (MDA in the above tissues. Hexane extract decreases both arsenic level and MDA level in rat tissues in dose dependent manner, which is more effective at lower doses.

Effect of hexane extract of spinach in the removal of arsenic from rat

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Badar Uddin Umar

2007-06-01

Full Text Available Extensive search is going on for a cheap, easily available and effective remedy of chronic arsenic poisoning. The present study was designed to find the effects of hexane extract of spinach in the removal of arsenic from arsenic treated rat. Rats were fed arsenic trioxide through Ryle’s tube for one month then they were fed on hexane extract (1-4% of spinach for another one month. Hexane extract of spinach decreased accumulated arsenic from rat liver, spleen, kidney, intestine, lungs and skin significantly. Besides, it reduced the oxidative stress caused by arsenic which was evident by decreased levels of malondialdehyde (MDA in the above tissues. Hexane extract decreases both arsenic level and MDA level in rat tissues in dose dependent manner, which is more effective at lower doses.

Biodegradable films of starch/PVOH/alginate in packaging systems for minimally processed lettuce (Lactuca sativa L.

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Renata Paula Herrera Brandelero

Full Text Available ABSTRACT Biodegradable packaging may replace non-biodegradable materials when the shelf life of the packaged product is relatively short, as in minimally processed foods. The objective of this work was to evaluate the efficiency of biodegradable films comprising starch/polyvinyl alcohol (PVOH/alginate with the addition of 0 or 0.5% of essential oil of copaiba (EOCP or lemongrass (EOLM compared to poly-vinyl chloride (PVC films in the storage of minimally processed lettuce. Lettuce samples cut into 1-cm strips were placed in polypropylene trays wrapped with biodegradable films and stored at 6 ± 2 °C for 8 days. PVC films were used as controls. The biofilms presented 11.43-8.11 MPa resistance and 11.3-13.22% elongation, with water vapor permeability (WVP of 0.5-4.04 x 10-12 g. s-1.Pa-1.m-1; thus, the films' properties were considered suitable for the application. The lettuce stored in PVC presented minor total soluble solids (TSS, less luminosity (L, higher intensity of yellow color (b, and eight times less mass loss than that stored in biodegradable films. Multivariate analysis showed that the lettuce lost quality after 2 days of storage in PVC films, representing a different result from the other treatments. Lettuce stored in biodegradable films for 2 and 4 days showed a greater similarity with newly harvested lettuce (time zero. The films with or without the addition of essential oil showed similar characteristics. Biodegradable films were considered viable for the storage of minimally processed lettuce.

Strain-Level Discrimination of Shiga Toxin-Producing Escherichia coli in Spinach Using Metagenomic Sequencing.

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Susan R Leonard

Full Text Available Consumption of fresh bagged spinach contaminated with Shiga toxin-producing Escherichia coli (STEC has led to severe illness and death; however current culture-based methods to detect foodborne STEC are time consuming. Since not all STEC strains are considered pathogenic to humans, it is crucial to incorporate virulence characterization of STEC in the detection method. In this study, we assess the comprehensiveness of utilizing a shotgun metagenomics approach for detection and strain-level identification by spiking spinach with a variety of genomically disparate STEC strains at a low contamination level of 0.1 CFU/g. Molecular serotyping, virulence gene characterization, microbial community analysis, and E. coli core gene single nucleotide polymorphism (SNP analysis were performed on metagenomic sequence data from enriched samples. It was determined from bacterial community analysis that E. coli, which was classified at the phylogroup level, was a major component of the population in most samples. However, in over half the samples, molecular serotyping revealed the presence of indigenous E. coli which also contributed to the percent abundance of E. coli. Despite the presence of additional E. coli strains, the serotype and virulence genes of the spiked STEC, including correct Shiga toxin subtype, were detected in 94% of the samples with a total number of reads per sample averaging 2.4 million. Variation in STEC abundance and/or detection was observed in replicate spiked samples, indicating an effect from the indigenous microbiota during enrichment. SNP analysis of the metagenomic data correctly placed the spiked STEC in a phylogeny of related strains in cases where the indigenous E. coli did not predominate in the enriched sample. Also, for these samples, our analysis demonstrates that strain-level phylogenetic resolution is possible using shotgun metagenomic data for determining the genomic relatedness of a contaminating STEC strain to other

Sustainable lettuce: Adaptability to uncertain production conditions

Science.gov (United States)

Lettuce is a popular and widely consumed leafy vegetable. California and Arizona annually produce more than 250,000 acres of iceberg, romaine, leaf, and specialty types of lettuce, supplying more than 95% of the U.S market as well as exports to Canada and other countries. These states have dominat...

Nutritional value, bioactive compounds, and health benefits of lettuce (Lactuca sativa L.)

Science.gov (United States)

Lettuce is one of the most popularly consumed vegetables worldwide but its nutritional value has been underestimated. Lettuce is low in calories and fat but high in fiber. Moreover, lettuce is high in potassium but low in sodium. Lettuce is also a good source of health-beneficial bioactive compounds...

Evaluation of the oil Produced from lettuce crop cultivated under three irrigation conditions

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Hassan El-Mallah, M.

2012-10-01

Full Text Available Three oil lettuce seed samples (lactuca Sativa LS10, LS20, LS30 were cultivated under three irrigation conditions (well, normal and water deficient conditions, after 10, 20 and 30 days respectively to evaluate their oils and to see to what extent the oil lettuce plant resists draught conditions. The oils extracted from the three seed samples were evaluated by determining eight lipid profiles using HPLC in conjunction with capillary GLC. Lettuce seed oils are characterized by high contents of linoleic and oleic acids. Of the triacyl glycerols determined, those containing linoleyl and oleyl acyles are the major ones. The whole sterol profiles include β-sitosterol (as major component followed by 7-stigmasterol, campesterol and 5-stigmasterol, which were found in all the lettuce seed oil samples but with slight differences. Furthermore, sterol patterns of the free and acylated sterols, free and acylated sterylglycosides were determined. It was found that LS30 oil has the highest tocopherol content and α-tocopherol is the only constituent in all the lettuce seed oil samples. On the other hand, the 2-position in the lettuce seed oil samples is mainly acylated by unsaturated fatty acids (98.6% namely, oleic and linoleic acids. According to these results, it can be concluded that irrigation conditions do not affect the lipid constituents of the oil and the oil lettuce plant resists draught and its lipid profiles are in agreement with those of conventional vegetable oils.

Tres muestras de semillas de lechuga (Lactuca Sativa LS10, LS20, LS30 se cultivaron bajo tres condiciones de riego (bien regado, normal y con deficiencia de agua, después de 10, 20 y 30 días, respectivamente para evaluar sus aceites y ver hasta qué punto el aceite de la planta de lechuga resiste las condiciones de riego. Los aceites extraídos de las tres muestras de semillas se evaluó mediante la determinación de ocho perfiles de lípidos usando cromatograf

Agronomic efficiency of intercropping tomato and lettuce

Directory of Open Access Journals (Sweden)

Arthur B. Cecílio Filho

2011-09-01

Full Text Available Four experiments were carried out at the São Paulo State University, Brazil, with the aim of determining the agronomic viability of intercropping tomato and lettuce, under greenhouse conditions. The studied intercropping systems were established by transplanting lettuce at 0, 10, 20 and 30 days after transplanting (DAT tomato and by transplanting tomato at 0, 10, 20 and 30 DAT lettuce. Intercropped tomato and lettuce were evaluated during two seasons and compared to their sole cropping. The experimental design was a randomized complete block with nine treatments. The productivity and the classification of the tomato fruits were not influenced by having lettuce intercropped with it, but lettuce production was lowered when tomato was intercropped with it. The longer the delay in lettuce transplanting, the greater the reduction in its productivity. There was an effect of cropping season on the extent of the agronomic advantage of intercropping over sole cropping. In the first cropping season, intercropping established by transplanting lettuce during the interval between 30 days before up to 20 DAT tomato yielded land use efficiency (LUE indices of 1.63 to 2.22. In the second period, intercropping established with the transplanting of lettuce up to 30 days before tomato yielded LUE indices of 1.57 to 2.05.Quatro experimentos foram conduzidos na Unesp, Brasil, com o objetivo de determinar a viabilidade agronômica de cultivos consorciados de alface e tomate em ambiente protegido. Consórcios estabelecidos por transplantes da alface aos 0, 10, 20 e 30 dias após o transplante (DAT do tomate e de tomate aos 0, 10, 20 e 30 DAT da alface, foram avaliados em duas épocas e comparados às suas monoculturas. Cada experimento foi conduzido em delineamento de blocos ao acaso, com nove tratamentos. Verificou-se que a produtividade do tomate e a classificação dos frutos não foram influenciadas pela alface, mas a produção da alface foi menor em cons

Combination treatment of chlorine dioxide gas and aerosolized sanitizer for inactivating foodborne pathogens on spinach leaves and tomatoes.

Science.gov (United States)

Park, Sang-Hyun; Kang, Dong-Hyun

2015-08-17

The objective of this study was to evaluate the antimicrobial effect of chlorine dioxide (ClO2) gas and aerosolized sanitizer, when applied alone or in combination, on the survival of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes inoculated onto spinach leaves and tomato surfaces. Spinach leaves and tomatoes were inoculated with a cocktail of three strains each of the three foodborne pathogens. ClO2 gas (5 or 10 ppmv) and aerosolized peracetic acid (PAA) (80 ppm) were applied alone or in combination for 20 min. Exposure to 10 ppmv of ClO2 gas for 20 min resulted in 3.4, 3.3, and 3.4 log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes on spinach leaves, respectively. Treatment with 80 ppm of aerosolized PAA for 20 min caused 2.3, 1.9, and 0.8 log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. Combined treatment of ClO2 gas (10 ppmv) and aerosolized PAA (80 ppm) for 20 min caused 5.4, 5.1, and 4.1 log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively. E. coli O157:H7, S. Typhimurium, and L. monocytogenes on tomatoes experienced similar reduction patterns to those on spinach leaves. As treatment time increased, most combinations of ClO2 gas and aerosolized PAA showed additive effects in the inactivation of the three pathogens. Combined treatment of ClO2 gas and aerosolized PAA produced injured cells of three pathogens on spinach leaves while generally did not produce injured cells of these pathogens on tomatoes. Combined treatment of ClO2 gas (10 ppmv) and aerosolized PAA (80 ppm) did not significantly (p>0.05) affect the color and texture of samples during 7 days of storage. Copyright © 2015. Published by Elsevier B.V.

Interaction of Escherichia coli with growing salad spinach plants.

Science.gov (United States)

Warriner, Keith; Ibrahim, Faozia; Dickinson, Matthew; Wright, Charles; Waites, William M

2003-10-01

In this study, the interaction of a bioluminescence-labeled Escherichia coli strain with growing spinach plants was assessed. Through bioluminescence profiles, the direct visualization of E. coli growing around the roots of developing seedlings was accomplished. Subsequent in situ glucuronidase (GUS) staining of seedlings confirmed that E. coli had become internalized within root tissue and, to a limited extent, within hypocotyls. When inoculated seeds were sown in soil microcosms and cultivated for 42 days, E. coli was recovered from the external surfaces of spinach roots and leaves as well as from surface-sterilized roots. When 20-day-old spinach seedlings (from uninoculated seeds) were transferred to soil inoculated with E. coli, the bacterium became established on the plant surface, but internalization into the inner root tissue was restricted. However, for seedlings transferred to a hydroponic system containing 10(2) or 10(3) CFU of E. coli per ml of the circulating nutrient solution, the bacterium was recovered from surface-sterilized roots, indicating that it had been internalized. Differences between E. coli interactions in the soil and those in the hydroponic system may be attributed to greater accessibility of the roots in the latter model. Alternatively, the presence of a competitive microflora in soil may have restricted root colonization by E. coli. The implications of this study's findings with regard to the microbiological safety of minimally processed vegetables are discussed.

Delineamento experimental e tamanho de amostra para alface cultivada em hidroponia Experimental design and sample size for hydroponic lettuce crop

Directory of Open Access Journals (Sweden)

Valéria Schimitz Marodim

2000-10-01

Full Text Available Este estudo visa a estabelecer o delineamento experimental e o tamanho de amostra para a cultura da alface (Lactuca sativa em hidroponia, pelo sistema NFT (Nutrient film technique. O experimento foi conduzido no Laboratório de Cultivos Sem Solo/Hidroponia, no Departamento de Fitotecnia da Universidade Federal de Santa Maria e baseou-se em dados de massa de plantas. Os resultados obtidos mostraram que, usando estrutura de cultivo de alface em hidroponia sobre bancadas de fibrocimento com seis canais, o delineamento experimental adequado é blocos ao acaso se a unidade experimental for constituída de faixas transversais aos canais das bancadas, e deve ser inteiramente casualizado se a bancada for a unidade experimental; para a variável massa de plantas, o tamanho da amostra é de 40 plantas para uma semi-amplitude do intervalo de confiança em percentagem da média (d igual a 5% e de 7 plantas para um d igual a 20%.This study was carried out to establish the experimental design and sample size for hydroponic lettuce (Lactuca sativa crop under nutrient film technique. The experiment was conducted in the Laboratory of Hydroponic Crops of the Horticulture Department of the Federal University of Santa Maria. The evaluated traits were plant weight. Under hydroponic conditions on concrete bench with six ducts, the most indicated experimental design for lettuce is randomised blocks for duct transversal plots or completely randomised for bench plot. The sample size for plant weight should be 40 and 7 plants, respectively, for a confidence interval of mean percentage (d equal to 5% and 20%.

Element contents and food safety of water spinach (Ipomoea aquatica Forssk.) cultivated with wastewater in Hanoi, Vietnam

DEFF Research Database (Denmark)

Marcussen, Helle; Jørgensen, Karin; Holm, Peter E.

2008-01-01

Extensive aquatic or semi-aquatic production of water spinach (Ipomoea aquatica Forssk.) for human consumption takes place in Southeast Asia. The aim of this study was to assess the concentrations of 38 elements in soil and water spinach cultivated under different degrees of wastewater exposure...... in Hanoi, Vietnam. The results showed no effect of wastewater use on the overall element concentrations in soil and water spinach. Mean soil concentrations for selected potentially toxic elements at the studied field sites had the following ranges 9.11-18.7 As, 0.333-0.667 Cd, 10.8-14.5 Co, 68-122 Cr, 34...... concentrations in water spinach were 0.139 As, 0.032 Cd, 0.135 Cr, 2.01 Cu, 39.1 Fe, 57.3 Mn, 0.16 Ni, 0.189 Pb and 6.01 Zn mg kg(-1) fresh weight (f.w.). The site and soil content of organic carbon were found to have high influence on the water spinach element concentrations whereas soil pH and the total soil...

40 CFR 180.253 - Methomyl; tolerances for residues.

Science.gov (United States)

2010-07-01

..., grain 1 Oat, hay 10 Oat, straw 10 Onion, green 3 Orange, sweet 2 Parsley, leaves 6 Pea 5 Pea, field...), kale, lettuce, mustard greens, parsley, spinach, Swiss chard, turnip, greens (tops), and watercress] 0...

EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2013. Scientific Opinion on the substantiation of a health claim related to a combination of red spinach, green spinach, red chicory, green chicory, green leaf chard, red leaf chard, red Swiss chard, golden Swiss chard

DEFF Research Database (Denmark)

Tetens, Inge

related to a combination of red spinach, green spinach, red chicory, green chicory, green leaf chard, red leaf chard, red Swiss chard, golden Swiss chard and white Swiss chard and protection of blood lipids from oxidative damage. The food that is the subject of the health claim, a combination...... of the following frozen vegetables: red spinach (Spinacia oleracea L.), green spinach (Spinacia oleracea L.), red chicory (Cichorium intybus L.), green chicory (Cichorium intybus L.), green leaf chard (Beta vulgaris L. var. cicla), red leaf chard (Beta vulgaris L. var. cicla), red Swiss chard (Beta vulgaris L. var...... conclusions could be drawn for the scientific substantiation of the claim were provided by the applicant. The Panel concludes that a cause and effect relationship has not been established between consumption of a combination of red spinach, green spinach, red chicory, green chicory, green leaf chard, red leaf...

EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2013. Scientific Opinion on the substantiation of a health claim related to a combination of red spinach, green spinach, red chicory, green chicory, green leaf chard, red leaf chard, red Swiss chard, golden Swiss chard

DEFF Research Database (Denmark)

Tetens, Inge

related to a combination of red spinach, green spinach, red chicory, green chicory, green leaf chard, red leaf chard, red Swiss chard, golden Swiss chard and white Swiss chard and maintenance of normal blood cholesterol concentration. The food that is the subject of the health claim, a combination of red...... spinach (Spinacia oleracea L.), green spinach (Spinacia oleracea L.), red chicory (Cichorium intybus L.), green chicory (Cichorium intybus L.), green leaf chard (Beta vulgaris L. var. cicla), red leaf chard (Beta vulgaris L. var. cicla), red Swiss chard (Beta vulgaris L. var. cicla), golden Swiss chard...... for the scientific substantiation of the claim were provided by the applicant. The Panel concludes that a cause and effect relationship has not been established between consumption of a combination of red spinach, green spinach, red chicory, green chicory, green leaf chard, red leaf chard, red Swiss chard, golden...

Effect of residual monomer from polyacrylamide on head lettuce grown in peat substrate.

Science.gov (United States)

Mroczek, Ewelina; Kleiber, Tomasz; Konieczny, Piotr; Waśkiewicz, Agnieszka

2015-01-01

The paper investigates the migration of the acrylamide monomer (AMD) to lettuce chosen as a test plant growing in an organic medium (peat substrate). Polyacrylamide (PAM)-based flocculant added to the growing medium contained no more than 1000 mg kg(-1) of AMD. Plants were grown with varied doses of PAM preparation (0.5-3.0 mg dm(-3) of peat substrate) to compare the results with the control sample. The determination of AMD content, chlorophyll content, weight of the lettuce head, and also analysis of macro- and micro-elements in lyophilised test material was made under the same analytical conditions. The results showed that lettuce plants absorb AMD to the leaves from the peat substrate. The AMD uptake has a negative impact on the growth of lettuce. It reduces the average fresh weight of heads and destabilises the mineral composition of the plant. Therefore, concern related to the transfer risk of the residual AMD from sludge used for organic fertilisation of edible plants still remains a crucial question from a food and consumer safety point of view. To ensure consumer safety, the fate of the AMD following the application of PAM to cropland should be carefully monitored in the whole food chain.

Activity of aphids associated with lettuce and broccoli in Spain and their efficiency as vectors of Lettuce mosaic virus.

Science.gov (United States)

Nebreda, M; Moreno, A; Pérez, N; Palacios, I; Seco-Fernández, V; Fereres, A

2004-03-01

This research sought to identify the aphid virus vector species associated with lettuce and broccoli crops in Spain, and to determine their population dynamics and ability to transmit Lettuce mosaic virus (LMV). Green tile traps and Moericke yellow water-pan traps were used to monitor aphid flights during the spring and autumn growing seasons of 2001. Aphid species feeding on lettuce were counted weekly. The transmission efficiencies of LMV were determined for the aphid species caught most frequently. The Moericke traps generally caught more aphid species than the tile trap, but the latter was the most suitable to estimate flight activity of species involved in virus spread. Spring aphid catches indicated that the main aphid species landing on lettuce in the regions of Madrid and Murcia was Hyperomyzus lactucae, but Brachycaudus helichrysi was also abundant in both regions. In broccoli in the Navarra region, the most abundant species in spring were Aphis fabae, B. helichrysi and H. lactucae. In autumn-sown crops, the main species landing on lettuce in the Madrid region were Hyadaphis coriandri and Aphis spiraecola. In Murcia, A. spiraecola and Myzus persicae were the most abundant, while in Navarra, Therioaphis trifolii, and various Aphis spp. were the most numerous landing on broccoli. The main aphid species colonising lettuce was Nasonovia ribisnigri, but other less abundant colonising species were Aulacorthum solani and Macrosiphum euphorbiae. The most efficient vectors of LMV were M. persicae, Aphis gossypii and M. euphorbiae, while A. fabae and H. lactucae transmitted with low efficiency, and Rhopalosiphum padi and N. ribisnigri did not transmit. Occurrence of LMV epidemics in central Spain in relation to aphid flights and the role of weeds as virus reservoirs is discussed.

Chemical removal of radionuclides in contaminated spinach derived from the Fukushima nuclear accident

International Nuclear Information System (INIS)

Shiba, Kazuhiro; Kitamura, Yoji; Kozaka, Takashi; Uno, Izumi; Miyoshi, Hirokazu; Yanaga, Makoto

2012-01-01

We examined a simple and effective removal method for contaminated farm products to ensure the relief of farmers and the security of consumers. Removal of radionuclides from spinach by chemical methods was investigated. The result of chemical removal showed that antioxidant agents removed radionuclides from spinach by 70–80% for 131 I and more than 80% for radiocesium. In particular, ascorbic acid is promising as a safe and versatile option. (author)

Assessment of Agronomic and Morphological Characteristics of Iranian Spinach Landrace in Esfahan Province

Directory of Open Access Journals (Sweden)

peyman jafari

2017-10-01

Full Text Available Introduction: Spinach is one of the most important leafy vegetables, rich in calcium, phosphorus, potassium, vitamin C and B-carotene, and it is likely to be Iran's origin. More than 30 percent of the area under cultivation of in Iran leafy vegetables, allocated to spinach plant. Spinach is a cool season crop and its cultivation is done in the fall and in early spring. Various regions of Iran, has the vast genetic diversity in relation to the mass of spinach. In a study to evaluate the yield and agronomic traits spinach 121 mass Iran, the masses were divided into six clusters that each cluster has specific morphological and agronomic traits. Leafy vegetables, especially spinach are the main sources of nitrate absorption and about 70 percent of total dietary nitrate intake per person per day is provided by leafy vegetables. Material and Methods: To study the preliminary agronomic and morphological traits and nitrate amounts of 100 Iranian spinach mass are available in GenBank, an investigation was carried out in Agriculture and Education Center Research in Esfahan for two years (2013-2014 by using of five mass dominant cultivars, and two control landrace (Varamin 88 and Varamin prickly seed. The aim of the first year of the study was the primary isolation of superior landraces based on agronomic traits of spinach. At the end of the first year of growth, seed traits, including the type (smooth-prick, the width of the blade, leaf color, wrinkling of leaf area, leaf thickness, the petiole (standing, half-standing and sleeping, petiole length, shape of leaf, the shape of the leaf tip, bolting during plant growth and the number of male and female were determined. A total of 25 landraces selected in the first year of study were compared in the second year using a randomized complete block design with three replications. Studied traits were: yield, dry matter yield, number of leaves, leaf length, leaf width, and petiole length and nitrate levels

USE OF PELLETED LETTUCE SEEDS IN BIOAVAILABILITY STUDIES

Science.gov (United States)

Lettuce (Latuca sativa L., cv. Buttercrunch) is one of the most common and sensitive test organisms, among plants, used in toxicology and bioavailability studies. Much of the available lettuce seeds in commercial channels are pelleted to allow for precision machine planting. Th...

USE OF PELLETED LETTUCE SEEDS IN BIOABAILABILITY STUDIES

Science.gov (United States)

Lettuce (Latuca sativa L., cv. Buttercrunch) is one of the most common and sensitive test organisms, among plants, used in toxicology and bioavailability studies. Much of the available lettuce seeds in commercial channels are pelleted to allow for precision machine planting. Th...

University Opinion Poll 9: Child Care, MPIRG, Lettuce. Preliminary Report.

Science.gov (United States)

Matross, Ronald; And Others

The University Opinion Poll conducted a survey of student opinion on issues related to University-sponsored day care, the role of the Minnesota Public Interest Research Group (MPIRG) and the University's policy on buying lettuce for its food services. Four hundred fifty-two respondents, 76% of a random sample of University of Minnesota students,…

Lettuce achene invigoration through osmopriming at supraoptimal temperature

International Nuclear Information System (INIS)

Jahangir, M.M.; Amjad, M.; Iqbal, Q.; Nawaz, A.; Afzal, I.

2009-01-01

The effect of osmopriming on lettuce achene invigoration at supra optimal temperature (35degreeC) was investigated in the present study. Osmopriming of lettuce achene with KNO/sub 3/ (0.25%, 0.5% and 1%), CaCl/sub 2/ (15 mM, 25 mM, 50 mM) and PEG 8000 (0.1 g/ml H/sub 2/O, 0.2 g/ml H/sub 2/O, 0.3g/ml H/sub 2/O) alleviated thermodormancy and improved lettuce achene's vigor. Moreover, priming significantly improved final germination % age, energy of germination, germination index, shoot length, root length, vigor index and reduced mean germination time and time taken to 50% germination, as compared to control, when seeds were subjected to supra-optimal germination environments. It can be concluded that osmopriming can act as effective tool to invigorate lettuce seeds at supra optimal temperature. (author)

Agronomic aspects of strip intercropping lettuce with alyssum for biological control of aphids

OpenAIRE

Brennan, Eric B.

2013-01-01

Organic lettuce growers in California typically use insectary strips of alyssum (Lobularia maritima (L.) Desv.) to attract hoverflies (Syrphidae) that provide biological control of aphids. A two year study with transplanted organic romaine lettuce in Salinas, California investigated agronomic aspects of lettuce monoculture and lettuce-alyssum strip intercropping on beds in replacement intercropping treatments where alyssum transplants replaced 2 to 8% of the lettuce transplants, and in additi...

Composition of hydroponic lettuce: effect of time of day, plant size, and season.

Science.gov (United States)

Gent, Martin P N

2012-02-01

The diurnal variation of nitrate and sugars in leafy green vegetables may vary with plant size or the ability of plants to buffer the uptake, synthesis, and use of metabolites. Bibb lettuce was grown in hydroponics in a greenhouse and sampled at 3 h intervals throughout one day in August 2007 and another day in November 2008 to determine fresh weight, dry matter, and concentration of nitrate and sugars. Plantings differing in size and age were sampled on each date. The dry/fresh weight ratio increased during the daylight period. This increase was greater for small compared to large plants. On a fresh weight basis, tissue nitrate of small plants was only half that of larger plants. The variation in concentration with time was much less for nitrate than for soluble sugars. Soluble sugars were similar for all plant sizes early in the day, but they increased far more for small compared to large plants in the long days of summer. The greatest yield on a fresh weight basis was obtained by harvesting lettuce at dawn. Although dry matter or sugar content increased later in the day, there is no commercial benefit to delaying harvest as consumers do not buy lettuce for these attributes. Copyright © 2011 Society of Chemical Industry.

Unravelling the resistance mechanism of lettuce against Nasonovia ribisnigri

OpenAIRE

Broeke, ten, C.J.M.

2013-01-01

Aphids are serious pests of crop plant species, and host plant resistance is often the most effective and environmentally friendly control strategy to control these pests. One of these aphid pests is the black currant - lettuce aphid, Nasonovia ribisnigri (Mosely), an economically important pest of cultivated lettuce, Lactuca sativa L. Host plant resistance has been used since 1982 to control this aphid species and is mediated by the Nr-gene, originating from wild lettuce Lactuca virosa L. H...

Employing Response Surface Methodology for the Optimization of Ultrasound Assisted Extraction of Lutein and β-Carotene from Spinach

Directory of Open Access Journals (Sweden)

Ammar Altemimi

2015-04-01

Full Text Available The extraction of lutein and β-carotene from spinach (Spinacia oleracea L. leaves is important to the dietary supplement industry. A Box-Behnken design and response surface methodology (RSM were used to investigate the effect of process variables on the ultrasound-assisted extraction (UAE of lutein and β-carotene from spinach. Three independent variables, extraction temperature (°C, extraction power (% and extraction time (min were studied. Thin-layer chromatography (TLC followed by UV visualization and densitometry was used as a simple and rapid method for both identification and quantification of lutein and β-carotene during UAE. Methanol extracts of leaves from spinach and authentic standards of lutein and β-carotene were separated by normal-phase TLC with ethyl acetate-acetone (5:4 (v/v as the mobile phase. In this study, the combination of TLC, densitometry, and Box–Behnken with RSM methods were effective for the quantitative analysis of lutein and β-carotene from spinach extracts. The resulting quadratic polynomial models for optimizing lutein and β-carotene from spinach had high coefficients of determination of 0.96 and 0.94, respectively. The optimal UAE settings for output of lutein and β-carotene simultaneously from spinach extracts were an extraction temperature of 40 °C, extraction power of 40% (28 W/cm3 and extraction time of 16 min. The identity and purity of each TLC spot was measured using time-of-flight mass spectrometry. Therefore, UAE assisted extraction of carotenes from spinach can provide a source of lutein and β-carotene for the dietary supplement industry.

The Protective Role of Lettuce oil (Lactuca sativa) against Radiation induced Biological Hazards in Male Rats

International Nuclear Information System (INIS)

Abdel-Magied, N.; Ahmed, A.G.

2011-01-01

This study was conducted to clarify the potential role of lettuce oil against damages induced in rats due to exposure to gamma radiation. Adult male albino rats (120-150 g) were divided into 4 groups each of 12 animals. The first group was considered control animals. The second group received, via gavages, lettuce oil (200 mg/Kg body weight) for 3 weeks. The third group was subjected to a single dose of 6.5Gy whole body gamma irradiation. The fourth group received lettuce oil for 3 weeks then was exposed to radiation. Blood samples were collected 1 and 7 days post irradiation. Exposure of rats to gamma irradiation caused a significant increase in the level of glucose, total cholesterol (TC), triglycerides (TG), malondialdehyde (MDA) and follicle stimulating hormone (FSH) while a significant decrease was recorded in glutathione content (GSH), superoxide dismutase (SOD) and catalase activities, white blood cells (WBCs), red blood cells (RBCs), haemoglobin content (Hb), haematocrit percentage (Hct%), mean corpuscular volume (MCV), platelets (PLT), leutinizing hormone (LH) and testosterone hormone . In rats treated with lettuce oil then exposed to radiation, the results showed an improvement in all previous parameters. It could be concluded that lettuce oil might reduce the biological hazards in rats induced by gamma irradiation

Marker-assisted selection for disease resistance in lettuce

Science.gov (United States)

Lettuce (Lactuca sativa L.) is the most popular leafy vegetable that is cultivated mainly in moderate climate. Consumers demand lettuce with good visual appearance and free of disease. Improved disease resistance of new cultivars is achieved by combining desirable genes (or alleles) from existing cu...

Chemical changes of spinach waste during composting and ...

African Journals Online (AJOL)

Considering this, the present study was planned to prepare compost and vermicompost of spinach collected from the supermarket of Amritsar and to estimate various chemical changes; nitrates, phosphates, sodium, potassium, calcium and pH during its composting and vermicomposting. It was observed that fresh vegetable ...

Absorption and biological half-life in humans of intrinsic and extrinsic 54Mn tracers from foods of plant origin

International Nuclear Information System (INIS)

Johnson, P.E.; Lykken, G.I.; Korynta, E.D.

1991-01-01

Absorption and biological half-life of 54 Mn were measured in adult men and women fed foods labeled intrinsically or extrinsically with 54 Mn. Each subject consumed a series of three test meals consisting of a food labeled intrinsically, a food labeled extrinsically or MnCl 2 (control) served in random order. The foods tested were lettuce, spinach, wheat and sunflower seeds. Lettuce meals and their controls contained 9.65 mumol Mn; other meals contained 22.50 mumol Mn. In addition to the test food or MnCl 2 , each meal consisted of vegetable oil (5 g), salt (NaCl, 0.15 g) and crackers (10 g), which provided 0.55 mumol Mn. There were no differences in percentage of Mn absorption or biological half-life of 54 Mn for any of the intrinsically/extrinsically labeled food pairs. Absorption of 54 Mn from MnCl 2 (8.90%) was greater than from lettuce (5.20%), spinach (3.81%), wheat (2.16%) or sunflower seeds (1.71%), but the biological half-life did not vary with the source of Mn. Absorption of 54 Mn from lettuce was significantly (P less than 0.05) greater than from wheat or sunflower seeds. Although the Mn dose in the test meal was less for lettuce than for the other foods, there was no difference in Mn absorption from MnCl 2 between the subjects fed lettuce and subjects fed other foods. There was no correlation of either 54 Mn absorption or biological half-life with whole blood or plasma Mn

Phytoextraction and estimating optimal time for remediation of Cd-contaminated soils by Spinach

OpenAIRE

Somayyeh Eisazadeh Lazarjan; safoora asadi kapourchal; Mehdi Homaee

2016-01-01

The so-called phytoextraction in which hyperaccumulator plants are used to remediate the contaminated soils is proven to be an efficient method. The objective of this study was to investigate the capability of Spinach for phytoremediation of cadmium from Cd-contaminated soils and determine the efficiency extent of spinach for phytoremediation. For this purpose, a randomized block experimental design whit five treatments including 0, 15, 30, 60 and 120 mg Cd/ kg soil and three replications was...

Microbial Profile of Soil-Free versus In-Soil Grown Lettuce and Intervention Methodologies to Combat Pathogen Surrogates and Spoilage Microorganisms on Lettuce

Directory of Open Access Journals (Sweden)

Sujata A. Sirsat

2013-11-01

Full Text Available Aquaponics is an effective method to practice sustainable agriculture and is gaining popularity in the US; however, the microbial safety of aquaponically grown produce needs to be ascertained. Aquaponics is a unique marriage of fish production and soil-free produce (e.g., leafy greens production. Fish are raised in fresh water tanks that are connected to water filled beds where fruits and vegetables are grown. The fish bi-products create nutrient-rich water that provides the key elements for the growth of plants and vegetables. The objective of this study was to perform a comparative analysis of the microbial safety and quality of aquaponic lettuce and soil grown lettuce (conventional, bagged, certified organic, and field lettuce. Following this, an intervention study was performed to combat foodborne pathogen surrogates (Salmonella and E. coli, spoilage, and fecal microorganisms using 2.5% acetic acid. The results of the comparative analysis study showed that aquaponically grown lettuce had significantly lower concentration of spoilage and fecal microorganisms compared to in-soil grown lettuce. The intervention study showed that diluted vinegar (2.5% acetic acid significantly reduced Salmonella, E. coli, coliforms, and spoilage microorganisms on fresh lettuce by 2 to 3 log CFU/g. Irrespective of growing methods (in-soil or soilless, it is crucial to incorporate good agricultural practices to reduce microbial contamination on fresh produce. The intervention employed in this study can be proposed to small farmers and consumers to improve quality and safety of leafy greens.

Microbial Profile of Soil-Free versus In-Soil Grown Lettuce and Intervention Methodologies to Combat Pathogen Surrogates and Spoilage Microorganisms on Lettuce.

Science.gov (United States)

Sirsat, Sujata A; Neal, Jack A

2013-11-11

Aquaponics is an effective method to practice sustainable agriculture and is gaining popularity in the US; however, the microbial safety of aquaponically grown produce needs to be ascertained. Aquaponics is a unique marriage of fish production and soil-free produce (e.g., leafy greens) production. Fish are raised in fresh water tanks that are connected to water filled beds where fruits and vegetables are grown. The fish bi-products create nutrient-rich water that provides the key elements for the growth of plants and vegetables. The objective of this study was to perform a comparative analysis of the microbial safety and quality of aquaponic lettuce and soil grown lettuce (conventional, bagged, certified organic, and field lettuce). Following this, an intervention study was performed to combat foodborne pathogen surrogates ( Salmonella and E. coli ), spoilage, and fecal microorganisms using 2.5% acetic acid. The results of the comparative analysis study showed that aquaponically grown lettuce had significantly lower concentration of spoilage and fecal microorganisms compared to in-soil grown lettuce. The intervention study showed that diluted vinegar (2.5% acetic acid) significantly reduced Salmonella , E. coli , coliforms, and spoilage microorganisms on fresh lettuce by 2 to 3 log CFU/g. Irrespective of growing methods (in-soil or soilless), it is crucial to incorporate good agricultural practices to reduce microbial contamination on fresh produce. The intervention employed in this study can be proposed to small farmers and consumers to improve quality and safety of leafy greens.

Effect of low-cost irrigation methods on microbial contamination of lettuce irrigated with untreated wastewater

DEFF Research Database (Denmark)

Keraita, Bernard; Konradsen, Flemming; Drechsel, P.

2007-01-01

OBJECTIVE: To assess the effectiveness of simple irrigation methods such as drip irrigation kits, furrow irrigation and use of watering cans in reducing contamination of lettuce irrigated with polluted water in urban farming in Ghana. METHODS: Trials on drip kits, furrow irrigation and watering...... cans were conducted with urban vegetable farmers. Trials were arranged in a completely randomised block design with each plot having all three irrigation methods tested. This was conducted in both dry and wet seasons. Three hundred and ninety-six lettuce, 72 soil, 15 poultry manure and 32 water samples...... were analysed for thermotolerant coliforms and helminth eggs. RESULTS: Lettuce irrigated with drip kits had the lowest levels of contamination, with, on average, 4 log units per 100 g, fewer thermotolerant coliforms than that irrigated with watering cans. However, drip kits often got clogged, required...

Effect of population density of lettuce intercropped with rocket on productivity and land-use efficiency

Science.gov (United States)

2018-01-01

The objective of this study was to evaluate the influence of the spacing of lettuce rows on the production of a lettuce-rocket intercropping system over two growing seasons (11 August to 25 September 2011 and 12 January to 24 February 2012) in Jaboticabal, São Paulo, Brazil. We evaluated 11 treatments in each season: lettuce-rocket intercrops with five row spacings for the lettuce (0.20, 0.25, 0.30, 0.35 and 0.40 m) and the rocket planted midway between the lettuce rows, sole crops of lettuce at the same five row spacings and a sole crop of rocket. Fresh and dry masses of the lettuce and rocket and number of lettuce leaves per plant were highest with a lettuce row spacing of 0.40 m, but the productivities of the lettuce and rocket were higher with a lettuce row spacing of 0.20 m. The productivities and fresh and dry weights of the lettuce and rocket and the number of lettuce leaves per plant were highest in the sole crops, but the fresh and dry weights of the rocket were higher with intercropping. The land equivalent ratios were >1.0 in both seasons in all intercrops and were highest for the densest crop (1.41). Intercropping was therefore 41% more efficient than sole cropping for the production of lettuce and rocket. PMID:29698401

Leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce

Science.gov (United States)

Rastogi, Gurdeep; Sbodio, Adrian; Tech, Jan J; Suslow, Trevor V; Coaker, Gitta L; Leveau, Johan H J

2012-01-01

The presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. However, information is scarce regarding their composition and how it changes along geographical and seasonal scales. We collected 106 samples of field-grown Romaine lettuce from commercial production regions in California and Arizona during the 2009–2010 crop cycle. Total bacterial populations averaged between 105 and 106 per gram of tissue, whereas counts of culturable bacteria were on average one (summer season) or two (winter season) orders of magnitude lower. Pyrosequencing of 16S rRNA gene amplicons from 88 samples revealed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundantly represented phyla. At the genus level, Pseudomonas, Bacillus, Massilia, Arthrobacter and Pantoea were the most consistently found across samples, suggesting that they form the bacterial ‘core' phyllosphere microbiota on lettuce. The foliar presence of Xanthomonas campestris pv. vitians, which is the causal agent of bacterial leaf spot of lettuce, correlated positively with the relative representation of bacteria from the genus Alkanindiges, but negatively with Bacillus, Erwinia and Pantoea. Summer samples showed an overrepresentation of Enterobacteriaceae sequences and culturable coliforms compared with winter samples. The distance between fields or the timing of a dust storm, but not Romaine cultivar, explained differences in bacterial community composition between several of the fields sampled. As one of the largest surveys of leaf surface microbiology, this study offers new insights into the extent and underlying causes of variability in bacterial community composition on plant leaves as a function of time, space and environment. PMID:22534606

Leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce.

Science.gov (United States)

Rastogi, Gurdeep; Sbodio, Adrian; Tech, Jan J; Suslow, Trevor V; Coaker, Gitta L; Leveau, Johan H J

2012-10-01

The presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. However, information is scarce regarding their composition and how it changes along geographical and seasonal scales. We collected 106 samples of field-grown Romaine lettuce from commercial production regions in California and Arizona during the 2009-2010 crop cycle. Total bacterial populations averaged between 10(5) and 10(6) per gram of tissue, whereas counts of culturable bacteria were on average one (summer season) or two (winter season) orders of magnitude lower. Pyrosequencing of 16S rRNA gene amplicons from 88 samples revealed that Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were the most abundantly represented phyla. At the genus level, Pseudomonas, Bacillus, Massilia, Arthrobacter and Pantoea were the most consistently found across samples, suggesting that they form the bacterial 'core' phyllosphere microbiota on lettuce. The foliar presence of Xanthomonas campestris pv. vitians, which is the causal agent of bacterial leaf spot of lettuce, correlated positively with the relative representation of bacteria from the genus Alkanindiges, but negatively with Bacillus, Erwinia and Pantoea. Summer samples showed an overrepresentation of Enterobacteriaceae sequences and culturable coliforms compared with winter samples. The distance between fields or the timing of a dust storm, but not Romaine cultivar, explained differences in bacterial community composition between several of the fields sampled. As one of the largest surveys of leaf surface microbiology, this study offers new insights into the extent and underlying causes of variability in bacterial community composition on plant leaves as a function of time, space and environment.

The Use of Some Morphological Traits for the Assessment of Genetic Diversity in Spinach (Spinacia Oleracea L. Landraces

Directory of Open Access Journals (Sweden)

Ebadi-Segheloo Asghar

2014-12-01

Full Text Available Investigation of native accessions of spinach (Spinacia oleracea L. would be aid in the development of new genetically improved varieties, so in this research 121 spinach landraces, collected from the various spinach growing areas of Iran, were evaluated to determine their diversity using several agro-morphological traits. High coefficients of variation (CV were recorded in fresh yield, leaf area and dry yield. Using principal component (PC analysis, the first three PCs with eigenvalues more than 0.9 contributed 80.56% of the variability among accessions. The first PC was related to leaf yield performance (fresh and dry yields, leaf numbers at flowering and lateral branches while the PC2 was related to leaf characteristic (leaf width, petiole length, petiole diameter and leaf area. The third PC was related to seed characteristic (seed yield and 1000-seed weight and was named as seed property component. The 121 spinach landraces were grouped into six clusters using cluster analysis. Each cluster had some specific characteristics of its own and the clusters I and II were clearly separated from clusters III and V and also from clusters IV and VI. The studied accessions are an important resource for the generation of a core collection of spinach in the world. The results of present research will support tasks of conservation and utilization of landraces in spinach breeding programs.

Site-directed mutagenesis of serine 158 demonstrates its role in spinach leaf sucrose-phosphate synthase modulation

Science.gov (United States)

Toroser, D.; McMichael, R. Jr; Krause, K. P.; Kurreck, J.; Sonnewald, U.; Stitt, M.; Huber, S. C.; Davies, E. (Principal Investigator)

1999-01-01

Site-directed mutagenesis of spinach sucrose-phosphate synthase (SPS) was performed to investigate the role of Ser158 in the modulation of spinach leaf SPS. Tobacco plants expressing the spinach wild-type (WT), S158A, S158T and S157F/S158E SPS transgenes were produced. Expression of transgenes appeared not to reduce expression of the tobacco host SPS. SPS activity in the WT and the S158T SPS transgenics showed light/dark modulation, whereas the S158A and S157F/S158E mutants were not similarly light/dark modulated: the S158A mutant enzyme was not inactivated in the dark, and the S157F/S158E was not activated in the light. The inability to modulate the activity of the S158A mutant enzyme by protein phosphorylation was demonstrated in vitro. The WT spinach enzyme immunopurified from dark transgenic tobacco leaves had a low initial activation state, and could be activated by PP2A and subsequently inactivated by SPS-kinase plus ATP. Rapid purification of the S158A mutant enzyme from dark leaves of transgenic plants using spinach-specific monoclonal antibodies yielded enzyme that had a high initial activation state, and pre-incubation with leaf PP2A or ATP plus SPS-kinase (the PKIII enzyme) caused little modulation of activity. The results demonstrate the regulatory significance of Ser158 as the major site responsible for dark inactivation of spinach SPS in vivo, and indicate that the significance of phosphorylation is the introduction of a negative charge at the Ser158 position.

Effect of gamma irradiation and refrigeration storage on microbial, sensorial and chemical quality of fresh-cut lettuce

International Nuclear Information System (INIS)

Hammad, A. A.; Taha, S. M.; Amal, S. M.; Gebreel, H. M.

2010-01-01

Fresh-cut lettuce samples were collected and examined for their microbial, sensory and chemical qualities. All the examined samples had high level of microbial load. All examined samples contained Escherichia coli (E. coli), Enterococcus faecalis (Ent. faecalis), Staphylococcus aureus (S. aureus) and Aeromonas hydrophila (A. hydrophila), indicating that most these samples were unsatisfactory. Listeria monocytogenes (L monocytogenes) and Salmonella spp were not detected. Irradiation caused a great reduction in all microbial loads. During refrigerated storage, the counts of all microorganisms increased, but the rate of increase was slower in irradiated samples. Irradiation dose of 3 kGy was the optimum dose for preservation of fresh-cut lettuce which extended the refrigeration shelf-life up to 20 days and it was sufficient in eliminating all pathogenic bacteria without adverse effect on sensorial quality and slight effect on chemical quality.

Liquid chromatography-tandem mass spectrometry method for simultaneous quantification of azoxystrobin and its metabolites, azoxystrobin free acid and 2-hydroxybenzonitrile, in greenhouse-grown lettuce.

Science.gov (United States)

Gautam, Maheswor; Fomsgaard, Inge S

2017-12-01

Lettuce is an important part of the diet in Europe. The permitted levels of pesticides in lettuce are strictly regulated and there is growing urge among food safety authorities to analyse pesticide metabolites as well. Azoxystrobin is one of pesticides that is frequently detected in lettuce. Although there are several analytical methods for the determination of azoxystrobin in lettuce, a sensitive method for the determination of its metabolites in lettuce is lacking. This study aimed at developing an extraction and LC-MS/MS method for the simultaneous determination of azoxystrobin, and its metabolites azoxystrobin free acid and 2-hydroxybenzonitrile in lettuce. Accelerated solvent extraction, QuEChERS extraction, and shaking extraction were compared using various solvents. The final method consisted of shaking freeze-dried sample in 0.1% formic acid in 80% aqueous acetonitrile. The selected method was validated by spiking each analyte at 125 ng/g and 500 ng/g. The method resulted in acceptable recovery for 2-hydroxybenzonitrile, azoxystrobin free acid, and azoxystrobin, with a RSD of lettuce.

A model for multiseasonal spread of verticillium wilt of lettuce.

Science.gov (United States)

Wu, B M; Subbarao, K V

2014-09-01

Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per

Survival and transfer of murine norovirus 1, a surrogate for human noroviruses, during the production process of deep-frozen onions and spinach.

Science.gov (United States)

Baert, Leen; Uyttendaele, Mieke; Vermeersch, Mattias; Van Coillie, Els; Debevere, Johan

2008-08-01

The reduction of murine norovirus 1 (MNV-1) on onions and spinach by washing was investigated as was the risk of contamination during the washing procedure. To decontaminate wash water, the industrial sanitizer peracetic acid (PAA) was added to the water, and the survival of MNV-1 was determined. In contrast to onions, spinach undergoes a heat treatment before freezing. Therefore, the resistance of MNV-1 to blanching of spinach was examined. MNV-1 genomic copies were detected with a real-time reverse transcription PCR assay in PAA-treated water and blanched spinach, and PFUs (representing infectious MNV-1 units) were determined with a plaque assay. A onion bulbs and spinach leaves. More than 3 log PFU of MNV-1 was transmitted to onion bulbs and spinach leaves when these vegetables were washed in water containing approximately 5 log PFU/ml. No decline of MNV-1 occurred in used industrial spinach wash water after 6 days at room temperature. A concentration of 20 ppm of PAA in demineralized water (pH 4.13) and in potable water (pH 7.70) resulted in reductions of 2.88 +/- 0.25 and 2.41 +/- 0.18 log PFU, respectively, after 5 min of exposure, but no decrease in number of genomic copies was observed. No reduction of MNV-1 PFUs was observed on frozen onions or spinach during storage for 6 months. Blanching spinach (80 degrees C for 1 min) resulted in at least 2.44-log reductions of infectious MNV-1, but many genomic copies were still present.

Real-time PCR detection of Listeria monocytogenes in infant formula and lettuce following macrophage-based isolation and enrichment.

Science.gov (United States)

Day, J B; Basavanna, U

2015-01-01

To develop a rapid detection procedure for Listeria monocytogenes in infant formula and lettuce using a macrophage-based enrichment protocol and real-time PCR. A macrophage cell culture system was employed for the isolation and enrichment of L. monocytogenes from infant formula and lettuce for subsequent identification using real-time PCR. Macrophage monolayers were exposed to infant formula and lettuce contaminated with a serial dilution series of L. monocytogenes. As few as approx. 10 CFU ml(-1) or g(-1) of L. monocytogenes were detected in infant formula and lettuce after 16 h postinfection by real-time PCR. Internal positive PCR controls were utilized to eliminate the possibility of false-negative results. Co-inoculation with Listeria innocua did not reduce the L. monocytogenes detection sensitivity. Intracellular L. monocytogenes could also be isolated on Listeria selective media from infected macrophage lysates for subsequent confirmation. The detection method is highly sensitive and specific for L. monocytogenes in infant formula and lettuce and establishes a rapid identification time of 20 and 48 h for presumptive and confirmatory identification, respectively. The method is a promising alternative to many currently used q-PCR detection methods which employ traditional selective media for enrichment of contaminated food samples. Macrophage enrichment of L. monocytogenes eliminates PCR inhibitory food elements and contaminating food microflora which produce cleaner samples that increase the rapidity and sensitivity of detection. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Validation of a Method for Cylindrospermopsin Determination in Vegetables: Application to Real Samples Such as Lettuce (Lactuca sativa L.

Directory of Open Access Journals (Sweden)

Ana I. Prieto

2018-02-01

Full Text Available Reports on the occurrence of the cyanobacterial toxin cylindrospermopsin (CYN have increased worldwide because of CYN toxic effects in humans and animals. If contaminated waters are used for plant irrigation, these could represent a possible CYN exposure route for humans. For the first time, a method employing solid phase extraction and quantification by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS of CYN was optimized in vegetables matrices such as lettuce (Lactuca sativa. The validated method showed a linear range, from 5 to 500 ng CYN g−1 of fresh weight (f.w., and detection and quantitation limits (LOD and LOQ of 0.22 and 0.42 ng CYN g−1 f.w., respectively. The mean recoveries ranged between 85 and 104%, and the intermediate precision from 12.7 to 14.7%. The method showed to be robust for the three different variables tested. Moreover, it was successfully applied to quantify CYN in edible lettuce leaves exposed to CYN-contaminated water (10 µg L−1, showing that the tolerable daily intake (TDI in the case of CYN could be exceeded in elderly high consumers. The validated method showed good results in terms of sensitivity, precision, accuracy, and robustness for CYN determination in leaf vegetables such as lettuce. More studies are needed in order to prevent the risks associated with the consumption of CYN-contaminated vegetables.

Validation of a Method for Cylindrospermopsin Determination in Vegetables: Application to Real Samples Such as Lettuce (Lactuca sativa L.).

Science.gov (United States)

Prieto, Ana I; Guzmán-Guillén, Remedios; Díez-Quijada, Leticia; Campos, Alexandre; Vasconcelos, Vitor; Jos, Ángeles; Cameán, Ana M

2018-02-01

Reports on the occurrence of the cyanobacterial toxin cylindrospermopsin (CYN) have increased worldwide because of CYN toxic effects in humans and animals. If contaminated waters are used for plant irrigation, these could represent a possible CYN exposure route for humans. For the first time, a method employing solid phase extraction and quantification by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) of CYN was optimized in vegetables matrices such as lettuce ( Lactuca sativa ). The validated method showed a linear range, from 5 to 500 ng CYN g -1 of fresh weight (f.w.), and detection and quantitation limits (LOD and LOQ) of 0.22 and 0.42 ng CYN g -1 f.w., respectively. The mean recoveries ranged between 85 and 104%, and the intermediate precision from 12.7 to 14.7%. The method showed to be robust for the three different variables tested. Moreover, it was successfully applied to quantify CYN in edible lettuce leaves exposed to CYN-contaminated water (10 µg L -1 ), showing that the tolerable daily intake (TDI) in the case of CYN could be exceeded in elderly high consumers. The validated method showed good results in terms of sensitivity, precision, accuracy, and robustness for CYN determination in leaf vegetables such as lettuce. More studies are needed in order to prevent the risks associated with the consumption of CYN-contaminated vegetables.

Weedborne reservoirs and seed transmission of Verticillium dahliae in lettuce

OpenAIRE

Vallad, G E; Bhat, R G; Koike, S T; Ryder, E J; Subbarao, K V

2005-01-01

The seed transmission of Verticillium dahliae was evaluated in lettuce (Lactuca sativa). Seed collected from lettuce plants infected with V. dahliae were plated with or without surface sterilization on Sorenson's modified NP10 medium. Of the seed plated with or without surface sterilization, 90 and 66 %, respectively, yielded colonies of V. dahliae. The incidence of Verticillium wilt ranged from 55 to 80 % among lettuce plants grown from seed harvested from infected plants. All evaluated isol...

Survival of Escherichia coli on Lettuce under Field Conditions Encountered in the Northeastern United States.

Science.gov (United States)

Weller, Daniel L; Kovac, Jasna; Roof, Sherry; Kent, David J; Tokman, Jeffrey I; Kowalcyk, Barbara; Oryang, David; Ivanek, Renata; Aceituno, Anna; Sroka, Christopher; Wiedmann, Martin

2017-07-01

Although wildlife intrusion and untreated manure have been associated with microbial contamination of produce, relatively few studies have examined the survival of Escherichia coli on produce under field conditions following contamination (e.g., via splash from wildlife feces). This experimental study was performed to estimate the die-off rate of E. coli on preharvest lettuce following contamination with a fecal slurry. During August 2015, field-grown lettuce was inoculated via pipette with a fecal slurry that was spiked with a three-strain cocktail of rifampin-resistant nonpathogenic E. coli. Ten lettuce heads were harvested at each of 13 time points following inoculation (0, 2.5, 5, and 24 h after inoculation and every 24 h thereafter until day 10). The most probable number (MPN) of E. coli on each lettuce head was determined, and die-off rates were estimated. The relationship between sample time and the log MPN of E. coli per head was modeled using a segmented linear model. This model had a breakpoint at 106 h (95% confidence interval = 69, 142 h) after inoculation, with a daily decrease of 0.70 and 0.19 log MPN for 0 to 106 h and 106 to 240 h following inoculation, respectively. These findings are consistent with die-off rates obtained in similar studies that assessed E. coli survival on produce following irrigation. Overall, these findings provide die-off rates for E. coli on lettuce that can be used in future quantitative risk assessments.

Identification, genetic localization, and allelic diversity of selectively amplified microsatellite polymorphic loci in lettuce and wild relatives (Lactuca spp.).

Science.gov (United States)

Witsenboer, H; Michelmore, R W; Vogel, J

1997-12-01

Selectively amplified microsatellite polymorphic locus (SAMPL) analysis is a method of amplifying microsatellite loci using generic PCR primers. SAMPL analysis uses one AFLP primer in combination with a primer complementary to microsatellite sequences. SAMPL primers based on compound microsatellite sequences provided the clearest amplification patterns. We explored the potential of SAMPL analysis in lettuce to detect PCR-based codominant microsatellite markers. Fifty-eight SAMPLs were identified and placed on the genetic map. Seventeen were codominant. SAMPLs were dispersed with RFLP markers on 11 of the 12 main linkage groups in lettuce, indicating that they have a similar genomic distribution. Some but not all fragments amplified by SAMPL analysis were confirmed to contain microsatellite sequences by Southern hybridization. Forty-five cultivars of lettuce and five wild species of Lactuca were analyzed to determine the allelic diversity for codominant SAMPLs. From 3 to 11 putative alleles were found for each SAMPL; 2-6 alleles were found within Lactuca sativa and 1-3 alleles were found among the crisphead genotypes, the most genetically homogeneous plant type of L. sativa. This allelic diversity is greater than that found for RFLP markers. Numerous new alleles were observed in the wild species; however, there were frequent null alleles. Therefore, SAMPL analysis is more applicable to intraspecific than to interspecific comparisons. A phenetic analysis based on SAMPLs resulted in a dendrogram similar to those based on RFLP and AFLP markers.

Stable plastid transformation in lettuce (Lactuca sativa L.).

Science.gov (United States)

Lelivelt, Cilia L C; McCabe, Matthew S; Newell, Christine A; Desnoo, C Bastiaan; van Dun, Kees M P; Birch-Machin, Ian; Gray, John C; Mills, Kingston H G; Nugent, Jacqueline M

2005-08-01

Although plastid transformation in higher plants was first demonstrated in the early 1990s it is only recently that the technology is being extended to a broader range of species. To date, the production of fertile transplastomic plants has been reported for tobacco, tomato, petunia, soybean, cotton and Lesquerella fendleri (Brassicaceae). In this study we demonstrate a polyethylene glycol-mediated plastid transformation system for lettuce that generates fertile, homoplasmic, plastid-transformed lines. Transformation was achieved using a vector that targets genes to the trnA/trnI intergenic region of the lettuce plastid genome employing the aadA gene as a selectable marker against spectinomycin. Spectinomycin resistance and heterologous gene transcription were shown in T(1) plants derived from self-pollinated primary regenerants demonstrating transmission of the plastid-encoded transgene to the first seed generation. Crossing with male sterile wild-type lettuce showed that spectinomycin resistance was not transmitted via pollen. Constructs containing the gfp gene showed plastid-based expression of green fluorescent protein. The lettuce plastid could have potential both as a production and a delivery system for edible human therapeutic proteins.

Ecdysteroid-containing food supplements from Cyanotis arachnoidea on the European market: evidence for spinach product counterfeiting

Science.gov (United States)

Hunyadi, Attila; Herke, Ibolya; Lengyel, Katalin; Báthori, Mária; Kele, Zoltán; Simon, András; Tóth, Gábor; Szendrei, Kálmán

2016-12-01

Phytoecdysteroids like 20-hydroxyecdysone (“ecdysterone”) can exert a mild, non-hormonal anabolic/adaptogenic activity in mammals, and as such, are frequently used in food supplements. Spinach is well-known for its relatively low ecdysteroid content. Cyanotis arachnoidea, a plant native in China, is among the richest sources of phytoecdysteroids, and extracts of this plant are marketed in tons per year amounts via the internet at highly competitive prices. Here we report the investigation of a series of food supplements produced in Germany and claimed to contain spinach extracts. Twelve ecdysteroids including two new compounds were isolated and utilized as marker compounds. A comparative analysis of the products with Cyanotis and spinach extracts provides evidence that they were manufactured from Cyanotis extracts instead of spinach as stated. Based on the chromatographic fingerprints, 20-hydroxyecdysone 2- and 3-acetate are suggested as diagnostic markers for related quality control. This case appears to represent an unusual type of dietary supplement counterfeiting: undeclared extracts from alternative plants would supposedly ‘guarantee’ product efficacy.

Factors important for the shelf-life of minimally processed lettuce

DEFF Research Database (Denmark)

Deza Durand, Karla Michelle

for a more comprehensive analyses as presented in paper IV. Paper III revealed that packaging and storage time had an influence on the volatiles of cut iceberg lettuce allowing the formation of desirable aroma but also on the development of off-odors. This result indicates that extremely low O2 and high CO2...... significantly higher in passive MAP F1. Regarding the cultivars, Morinas and Diamantinas was the less tolerant to high CO2 resulting in significantly higher amount of 2,3-butanedione. Paper V was related to browning and other physicochemical characteristics of minimally processed lettuce such as soluble sugars...... to influence the formation of browning and other physicochemical characteristics as storage time increased. It was concluded that browning was remarkable controlled in passive MAPs samples, irrespective of season and cultivar due to extremely low O2 and high CO2 conditions, however, after 11 days of storage...

Rapid cloning and bioinformatic analysis of spinach Y chromosome ...

Indian Academy of Sciences (India)

(DOP-PCR) products were hybridized with cDNA of the male spinach flowers in florescence. The female .... China), 1 μL (3.5 U/μL) T4 ligase and sterile double- distilled ... Cloning of hybrid PCR products and screening of cDNA sequence.

Prevalence and diversity of Salmonella enterica in water, fish and lettuce in Ouagadougou, Burkina Faso.

Science.gov (United States)

Traoré, Oumar; Nyholm, Outi; Siitonen, Anja; Bonkoungou, Isidore Juste O; Traoré, Alfred S; Barro, Nicolas; Haukka, Kaisa

2015-07-31

This study investigated the prevalence, serotypes and antimicrobial sensitivity patterns of Salmonella enterica in environment in Ouagadougou, Burkina Faso. A total of 476 samples, consisting of 36 samples of tap water, 51 samples of well water, 87 samples of channel water, 44 samples of reservoir water, 238 samples of fish, and 20 samples of lettuce were examined using standard bacteriological procedures for Salmonella. Salmonella were isolated from 98 samples. Salmonella were rare in drinking water, since they were not found at all from the tap water, and only in 2 % of well water. Salmonella were more common in the water of reservoir of Tanghin (15 %), reservoir of Yamtenga (20 %), and in the water channels in the city (from 20 to 31 %). Salmonella were commonly isolated from the fish (24 %) caught from the reservoir of Tanghin and from the lettuce (50 %) irrigated with water from Tanghin. The Salmonella isolates were found to represent 50 different serotypes. The 11 most common serotypes were Salmonella Bredeney and S. Colindale (both 8.2 %), S. Muenster (6.1 %), S. Korlebu (5.1 %), S. Eastbourne and S. Poona (both 4.1 %), and S. Agona, S. Derby, S. Drac, S. Senftenberg, S. Waycross (each 3.1 %), accounting for 51.3 % of all the isolates. In general, the Salmonella strains were sensitive to the antimicrobials tested, but two strains were resistant to streptomycin and many more intermediate to streptomycin or sulphonamide. This study highlights the common prevalence of Salmonella and the high diversity of Salmonella serotypes in aquatic environment in Ouagadougou, Burkina Faso. Therefore, various human activities linked to water and consumption of water-related products, such as fish and lettuce, can lead to human Salmonella infections.

Prevalence of Lettuce mosaic virus - common strain on three lettuce producing areas from São Paulo State

OpenAIRE

Firmino,Ana Carolina; Krause-Sakate,Renate; Pavan,Marcelo Agenor; Silva,Norberto da; Hanai,Sérgio Minoru; Anbo,Roberto Hiroto; Nietzsche,Thomas; Le Gall,Olivier

2008-01-01

LMV is one of the most important pathogens of lettuce worldwide. Based on their ability to overcome the resistance genes mo1¹ and mo1² in lettuce, isolates can be divided in two types: LMV-Most, which can infect and are seed-borne in cultivars containing the mo1 gene and LMV-Common, which do not cause symptoms on these cultivars and are seed transmitted only in susceptible cultivars. To evaluate the occurrence of these two types of LMV isolates, a survey was carried out during 2002-2005 in th...

Responses of Nasonovia ribisnigri (Homoptera: Aphididae) to susceptible and resistant lettuce.

Science.gov (United States)

Liu, Yong-Biao; McCreight, James D

2006-06-01

Nymphs and alates of aphid Nasonovia ribisnigri (Mosley) (Homoptera: Aphididae) were tested on 10 lettuce cultivars with N. ribisnigri resistance gene Nr and 18 cultivars without the resistance gene in various bioassays. Bioassays used whole plants, leaf discs, or leaf cages to determine susceptibility of commercial lettuce cultivars to N. ribisnigri infestation and to evaluate screening methods for breeding lettuce resistance to N. ribisnigri. Resistant and susceptible plants were separated in 3 d when using whole plant bioassays. Long-term (> or =7 d) no-choice tests using leaf cages or whole plants resulted in no survival of N. ribisnigri on resistant plants, indicating great promise of the Nr gene for management of N. ribisnigri. Effective screening was achieved in both no-choice tests where resistant or susceptible intact plants were tested separately in groups or individually and in choice tests where susceptible and resistant plants were intermixed. Leaf discs bioassays were not suitable for resistance screening. All lettuce cultivars without the resistance gene were suitable hosts for N. ribisnigri, indicating the great importance of this pest to lettuce production and the urgency in developing resistant lettuce cultivars to manage N. ribisnigri.

Genome-wide association study for lettuce cultivars with improved salad processing efficiency

Science.gov (United States)

Lettuce (Lactuca sativa L.) is widely used as the main ingredient of packaged leafy vegetable salads. Salad lettuce can have short shelf life, decaying as early as eight days after harvest and reducing the nutritional quality. Decayed lettuce is not marketable, produces extra waste, and results in t...

Decreasing the NO3 and increasing the vitamin C contents in spinach by a nitrogen deprivation method.

Science.gov (United States)

Mozafar, A

1996-02-01

Excessive use of nitrogen fertilizers is known to increase the NO3 and reduce the vitamin C contents in fruits and vegetables. We investigated the concentration of these compounds in spinach leaves when plants were transferred to nitrogen-free media prior to their harvest. It was noted that a pre-harvest transfer of spinach to N-free media reduces the NO3 and increases the vitamin C content of the leaves by a substantial amount in a 2-3 day period. It is suggested that this technique may be suited to produce spinach or other leafy vegetables with low NO3 and high vitamin C contents under commercial hydroponic conditions.

Impact of mulches and growing season on indicator bacteria survival during lettuce cultivation.

Science.gov (United States)

Xu, Aixia; Buchanan, Robert L; Micallef, Shirley A

2016-05-02

In fresh produce production, the use of mulches as ground cover to retain moisture and control weeds is a common agricultural practice, but the influence that various mulches have on enteric pathogen survival and dispersal is unknown. The goal of this study was to assess the impact of different mulching methods on the survival of soil and epiphytic fecal indicator bacteria on organically grown lettuce during different growing seasons. Organically managed lettuce, cultivated with various ground covers--polyethylene plastic, corn-based biodegradable plastic, paper and straw mulch--and bare ground as a no-mulch control, was overhead inoculated with manure-contaminated water containing known levels of generic Escherichia coli and Enterococcus spp. Leaves and soil samples were collected at intervals over a two week period on days 0, 1, 3, 5, 7, 10 and 14, and quantitatively assessed for E. coli, fecal coliforms and Enterococcus spp. Data were analyzed using mixed models with repeated measures and an exponential decline with asymptote survival model. Indicator bacterial concentrations in the lettuce phyllosphere decreased over time under all treatments, with more rapid E. coli declines in the fall than in the spring (plettuce compared to mulches. In fall 2014, the E. coli decline rate on paper mulch-grown lettuce was higher (plettuce phyllosphere, and mulch type was a factor for fecal coliform levels (plettuce production may impact the fate of enteric bacteria in soil or on lettuce, most likely in relation to soil moisture retention, and other weather-related factors, such as temperature and rainfall. The data suggest that the time between exposure to a source of enteric bacteria and harvesting of the crop is season dependent, which has implications for determining best harvest times. Copyright © 2016 Elsevier B.V. All rights reserved.

Alternative sanitization methods for minimally processed lettuce in comparison to sodium hypochlorite.

Science.gov (United States)

Bachelli, Mara Lígia Biazotto; Amaral, Rívia Darla Álvares; Benedetti, Benedito Carlos

2013-01-01

Lettuce is a leafy vegetable widely used in industry for minimally processed products, in which the step of sanitization is the crucial moment for ensuring a safe food for consumption. Chlorinated compounds, mainly sodium hypochlorite, are the most used in Brazil, but the formation of trihalomethanes from this sanitizer is a drawback. Then, the search for alternative methods to sodium hypochlorite has been emerging as a matter of great interest. The suitability of chlorine dioxide (60 mg L(-1)/10 min), peracetic acid (100 mg L(-1)/15 min) and ozonated water (1.2 mg L(-1)/1 min) as alternative sanitizers to sodium hypochlorite (150 mg L(-1) free chlorine/15 min) were evaluated. Minimally processed lettuce washed with tap water for 1 min was used as a control. Microbiological analyses were performed in triplicate, before and after sanitization, and at 3, 6, 9 and 12 days of storage at 2 ± 1 °C with the product packaged on LDPE bags of 60 μm. It was evaluated total coliforms, Escherichia coli, Salmonella spp., psicrotrophic and mesophilic bacteria, yeasts and molds. All samples of minimally processed lettuce showed absence of E. coli and Salmonella spp. The treatments of chlorine dioxide, peracetic acid and ozonated water promoted reduction of 2.5, 1.1 and 0.7 log cycle, respectively, on count of microbial load of minimally processed product and can be used as substitutes for sodium hypochlorite. These alternative compounds promoted a shelf-life of six days to minimally processed lettuce, while the shelf-life with sodium hypochlorite was 12 days.

Precut prepackaged lettuce: a risk for listeriosis?

Science.gov (United States)

Hanning, Irene B; Johnson, Michael G; Ricke, Steven C

2008-12-01

The most recent outbreaks of listeriosis have been traced back to contaminated ready-to-eat (RTE) poultry and meat products. However, Listeria monocytogenes can be isolated from every food group, including fresh vegetables. This review is focused on one of the most popular RTE vegetable products, precut prepackaged lettuce. The available literature concerning Listeria contamination of vegetables is reviewed, and possible reasons why no recent outbreaks or sporadic cases of listeriosis due to contaminated precut prepackaged lettuce are explored.

Evidence for the role of an invasive weed in widespread occurrence of phytoplasmal diseases in diverse vegetable crops: implications from lineage-specific molecular markers

Science.gov (United States)

During the period from 2011 to 2013, several plant diseases repeatedly occurred in vegetable crops grown in Yuanmou County, Yunnan Province, China. Affected plants included cowpea, sword bean, string bean, tomato, lettuce, and water spinach. The diseased plants exhibited symptoms of witches’-broom...

AND DEVELOPMENT OF LETTUCE ON CHERNOZEM ORDINARY

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N. V. Gromakova

2017-01-01

Full Text Available Lettuce is very popular in the Russian consumer market. Special conditions for its cultivation determine the need to select modern, inexpensive elements of agro-technology that promote high yields. At present biochar (bio-coal is considered as a promising organic fertilizer. Its main difference lies in the possibility of using any organic raw material in its production. In Russia, the study on the use of biochar is limited; there is no practice of applying it in the complex of agricultural techniques of various agricultural crops. In the conditions of vegetative experiment, the influence of various doses of biochar in ordinary chernozem on the growth and development of lettuce (Lactuca sativa cultivar was studied in accordance with the developed experiment scheme: control (without biochar, supplemented with 1, 2 and 5 % of biochar. In the experiment, biochar obtained from birch wood was used, by pyrolysis method in fraction of 0.5-5mm. The following observations and determinations were made: the timing of the onset of the phases of plant development, the length of the roots, the number of leaves, the length of the largest leaf, the height of plants, the diameter of the rosette, the mass of 10 plants. The use of biochar contributed to a reduction of beginning period technical ripeness in plants, particularly in variant with the addition of 2%. The increase in root length, the number of leaves of lettuce plants as compared with to control in variants with 2 and 5% of biocar has been observed. The length of the largest leaf, the height of plants and the diameter of the rosette of lettuce are characterized by a significant improvement, even in variant with 1%. Productivity of lettuce was highest in the variant with 2% of biochar applied to the soil.

Effect of a bacteriophage cocktail in combination with modified atmosphere packaging in controlling Listeria monocytogenes on fresh-cut spinach

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Boyacioglu O.

2016-06-01

Full Text Available A Listeria monocytogenes-specific bacteriophage cocktail was evaluated for its activity against a nalidixic acid-resistant L. monocytogenes (Lm-NalR isolate on fresh-cut spinach stored under modified atmosphere packaging at various temperatures. Pieces (~2 × 2 cm2 of fresh spinach inoculated with 4.5 log CFU/cm2 Lm-NalR were sprayed with the phage cocktail (6.5 log plaque-forming units [PFU]/cm2 or a control. The samples were stored at 4°C or 10°C for up to 14 d in sealed packages filled with either atmospheric air (AA or modified atmosphere (MA. At 4°C under AA, the phages significantly (P ≤ 0.05 lowered the Lm-NalR populations on spinach, compared to control-treated inoculated samples, by 1.12 and 1.51 log CFU/cm2 after 1 and 14 d, respectively. At 4°C under MA, Lm-NalR was significantly reduced by 1.95 log CFU/cm2 compared to control leaves after both 1 and 14 d. At 10°C under AA, the phages significantly reduced Lm-NalR by 1.50 and 2.51 log CFU/cm2 after 1 and 14 d compared to the control. Again at 10°C under MA, the phages significantly reduced Lm-NalR by 1.71 and 3.24 log CFU/cm2 compared to control after 1 and 14 d, respectively. The results support the potential of lytic bacteriophages in effectively reducing populations of L. monocytogenes on freshcut leafy produce, under both AA and MA conditions.

Abscisic Acid accumulation in spinach leaf slices in the presence of penetrating and nonpenetrating solutes.

Science.gov (United States)

Creelman, R A; Zeevaart, J A

1985-01-01

Abscisic acid (ABA) accumulated in detached, wilted leaves of spinach (Spinacia oleracea L. cv Savoy Hybrid 612) and reached a maximum level within 3 to 4 hours. The increase in ABA over that found in detached turgid leaves was approximately 10-fold. The effects of water stress could be mimicked by the use of thin slices of spinach leaves incubated in the presence of 0.6 molar mannitol, a compound which causes plasmolysis (loss of turgor). About equal amounts of ABA were found both in the leaf slices and in detached leaves, whereas 2 to 4 times more ABA accumulated in the medium than in the slices. When spinach leaf slices were incubated with ethylene glycol, a compound which rapidly penetrates the cell membrane causing a decrease in the osmotic potential of the tissue and only transient loss of turgor, no ABA accumulated. Ethylene glycol was not inhibitory with respect to ABA accumulation. Spinach leaf slices incubated in both ethylene glycol and mannitol had ABA levels similar to those found when slices were incubated with mannitol alone. Increases similar to those found with mannitol also occurred when Aquacide III, a highly purified form of polyethylene glycol, was used. Aquacide III causes cytorrhysis, a situation similar to that found in wilted leaves. Thus, it appears that loss of turgor is essential for ABA accumulation.When spinach leaf slices were incubated with solutes which are supposed to disturb membrane integrity (KHSO(3), 2-propanol, or KCl) no increase in ABA was observed. These data indicate that, with respect to the accumulation of ABA, mannitol caused a physical stress (loss of turgor) rather than a chemical stress (membrane damage).

DNA analysis in three populations of African spinach (Basella spp.)

International Nuclear Information System (INIS)

Grasso, G.; Van Duren, M.; Lee, K.S.; Morpurgo, R.

1997-01-01

African spinach (Basella spp.) is an important vegetable in West Africa, and was introduced by early colonialists. Its alien origin is supported by its narrow genetic variability. Flowcytometry and RAPD polymorphism were used to investigate genetic variation in three populations of Basella - 'Congo native', 'Cong domesticated', and an introduced cultivar, 'Sri Lanka' from Sri Lanka. Normal spinach (Spinacia oleracea) cv. 'Prince F 1 Hybrid' was used to test sensitivity and to verify detection of genetic variation. Nuclei were isolated from young leaves of Basella, stained with DAPI and ethidium bromide, and ploidy level and total DNA content were determined by using a flowcytometer. The two sexually propagated populations, 'Cong domesticated' and 'Sri Lanka' showed very low amount of genetic variation as revealed by RAPD analysis; the third population 'Congo native' showed a limited amount of polymorphism. (author). 8 refs, 1 fig., 2 tabs

STATISTIC MODELING OF DRYING KINETHIC OF SPINACH LEAVES USING MICROWAVE AND HOT AIR METHODS

OpenAIRE

Mojtaba Nouri; Marzieh Vahdani; Shilan Rashidzadeh; Lukáš Hleba; Mohammad Ali Shariati

2015-01-01

The target of this study was to model of spinach leaves drying using microwave and hot air dryer. This test performed in combination treatment of temperatures (50°C, 60°C, and 70°C) and microwave (90, 180, 360, 600 and 900w) in 3 replications. Sample moisture measured within drying. All the results were fitted and analyzed with 8 mathematical models base on 3 parameters including determination (R2), Chi square(X2), root mean square errors(RSME). Results also revealed that temperature and micr...

Carotenoids and flavonoids in organically grown spinach (Spinacia oleracea L) genotypes after deep frozen storage

DEFF Research Database (Denmark)

Kidmose, U.; Knuthsen, Pia; Edelenbos, M.

2001-01-01

storage the green colour was determined by sensory evaluation and HunterLab colorimetry. The content of individual chlorophylls, carotenoids and flavonoids was determined using HPLC. Lutein, beta -carotene, violaxanthin and 9 '-(Z)-neoxanthin were the main carotenoids in processed spinach. The total......After frozen storage the content of individual carotenoids and flavonoids was determined in organically grown spinach genotypes (Spinacia oleracea L) which differed in leaf colour and shape. The spinach was sorted, washed, blanched in steam for 3 min and frozen in liquid nitrogen. After frozen...... of lutein and neoxanthin varied significantly between genotypes, and the highest content was found in the dark green genotype (76.0 and 25.4 mg kg(-1) 'wet weight' as eaten respectively). The total flavonoid content and the relative content of individual flavonoids were found to vary between the six...

Concomitant uptake of antimicrobials and Salmonella in soil and into lettuce following wastewater irrigation

International Nuclear Information System (INIS)

Sallach, J. Brett; Zhang, Yuping; Hodges, Laurie; Snow, Daniel; Li, Xu; Bartelt-Hunt, Shannon

2015-01-01

The use of wastewater for irrigation may introduce antimicrobials and human pathogens into the food supply through vegetative uptake. The objective of this study was to investigate the uptake of three antimicrobials and Salmonella in two lettuce cultivars. After repeated subirrigation with synthetic wastewater, lettuce leaves and soil were collected at three sequential harvests. The internalization frequency of Salmonella in lettuce was low. A soil horizon-influenced Salmonella concentration gradient was determined with concentrations in bottom soil 2 log CFU/g higher than in top soil. Lincomycin and sulfamethoxazole were recovered from lettuce leaves at concentrations as high as 822 ng/g and 125 ng/g fresh weight, respectively. Antimicrobial concentrations in lettuce decreased from the first to the third harvest suggesting that the plant growth rate may exceed antimicrobial uptake rates. Accumulation of antimicrobials was significantly different between cultivars demonstrating a subspecies level variation in uptake of antibiotics in lettuce. - Highlights: • Antimicrobial uptake in lettuce is cultivar dependent. • Antimicrobial concentrations in lettuce decrease despite repeated exposure. • Lincomycin is better conserved in the soil-plant system than oxytetracycline or sulfamethoxazole. • Subirrigation resulted in more Salmonella in bottom soil than in top soil. • Internalization frequency of Salmonella in lettuce is low despite repeated exposure. - Cultivar-specific differences in lincomycin and sulfamethazine uptake were observed in lettuce, while uptake of Salmonella was low despite repeated exposure from wastewater

The effect of sewage sludge application on the growth and absorption rates of Pb and As in water spinach

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Rong Wang

2016-01-01

Full Text Available This paper investigated the effect of the application of sewage sludge on the growth rates and absorption rates of Pb and As in potted water spinach. Our results indicated that application of sewage sludge promoted vegetable growth, and the dry weight of water spinach reached a maximal value (4.38 ± 0.82 g upon 8% sludge application. We also found that the dry weights of water spinach after treatment were all greater than those of the control systems (CK. Treatment with sludge promoted the absorption of Pb and As in water spinach, with a significant (p < 0.05 increase of absorbed Pb following treatment concentrations above 10%, and a peak absorption of As at 8%. Finally, we found that concentrations of Pb and As were higher in rhizosphere-attached soil than in free pot.

Irradiated ready-to-eat spinach leaves: How information influences awareness towards irradiation treatment and consumer's purchase intention

Science.gov (United States)

Finten, G.; Garrido, J. I.; Agüero, M. V.; Jagus, R. J.

2017-01-01

This article aims to clarify and supply further information on food irradiation acceptance, with particular focus on Argentina and irradiated ready-to-eat (RTE) spinach leaves through an open web-online survey. Results showed that half of respondents did not know food irradiation, but the other half demonstrated uncertainty despite they declared they had knowledge about it; thus, confirming little awareness towards this technology. Respondents who believed in the misleading myth about food irradiation represented 39%, while roughly the same number was doubtful. On the other hand, after supplying informative material, respondents were positively influenced and an increase in acceptance by 90% was found. Finally, 42% of respondents were willing to consume/purchase irradiated RTE spinach leaves, and 35% remained doubtful. Respondents who did not exclude to accept irradiated spinach could be considered potential consumers if intensive campaigns about the benefits of food irradiation were carried out by reliable actors. If the Argentinean RTE market grew, following the world consumption trend towards these products, irradiated spinach leaves could be successfully introduced by making better efforts to inform consumers about food irradiation.

Antibacterial Activities of Hibiscus sabdariffa Extracts and Chemical Sanitizers Directly on Green Leaves Contaminated with Foodborne Pathogens.

Science.gov (United States)

Gómez-Aldapa, Carlos A; Rangel-Vargas, Esmeralda; Torres-Vitela, Ma Refugio; Villarruel-López, Angélica; Acevedo-Sandoval, Otilio A; Gordillo-Martínez, Alberto J; Godínez-Oviedo, Angélica; Castro-Rosas, Javier

2018-02-01

Leafy greens have been associated with foodborne disease outbreaks in different countries. To decrease microbial contamination of leafy greens, chemical agents are commonly used; however, a number of studies have shown these agents to have limited antimicrobial effect against pathogenic bacteria on vegetables. The objective of this study was to compare the antibacterial effect of Hibiscus sabdariffa calyx extracts (water, methanol, acetone, and ethyl acetate), sodium hypochlorite, acetic acid, and colloidal silver against foodborne bacteria on leafy greens. Thirteen foodborne bacteria were used in the study: Listeria monocytogenes, Shigella flexneri, Salmonella serotypes Typhimurium Typhi, and Montevideo, Staphylococcus aureus, Escherichia coli O157:H7, five E. coli pathotypes (Shiga toxin-producing, enteropathogenic, enterotoxigenic, enteroinvasive, and enteroaggregative), and Vibrio cholerae O1. Each foodborne bacterium was separately inoculated on romaine lettuce, spinach, and coriander leaves. Separately, contaminated leafy greens were immersed in four hibiscus extracts and in sanitizers for 5 min. Next, green leaves were washed with sterile tap water. Separately, each green leaf was placed in a bag that contained 0.1% sterile peptone water and was rubbed for 2 min. Counts were done by plate count using appropriate dilutions (in sterile peptone water) of the bacterial suspensions spread on Trypticase soy agar plates and incubated at 35 ± 2°C for 48 h. Statistically significant differences ( P caused a significantly greater reduction ( P contaminated romaine lettuce, spinach, and coriander than did the sodium hypochlorite, colloidal silver, and acetic acid. Dry roselle calyx extracts may potentially be a useful addition to disinfection procedures for romaine lettuce, spinach, and coriander.

Plastid transformation in lettuce (Lactuca sativa L.) by biolistic DNA delivery.

Science.gov (United States)

Ruhlman, Tracey A

2014-01-01

The interest in producing pharmaceutical proteins in a nontoxic plant host has led to the development of an approach to express such proteins in transplastomic lettuce (Lactuca sativa L.). A number of therapeutic proteins and vaccine antigen candidates have been stably integrated into the lettuce plastid genome using biolistic DNA delivery. High levels of accumulation and retention of biological activity suggest that lettuce may provide an ideal platform for the production of biopharmaceuticals.

Phytoremediation to remove nutrients and improve eutrophic stormwaters using water lettuce (Pistia stratiotes L.).

Science.gov (United States)

Lu, Qin; He, Zhenli L; Graetz, Donald A; Stoffella, Peter J; Yang, Xiaoe

2010-01-01

Water quality impairment by nutrient enrichment from agricultural activities has been a concern worldwide. Phytoremediation technology using aquatic plants in constructed wetlands and stormwater detention ponds is increasingly applied to remediate eutrophic waters. The objectives of this study were to evaluate the effectiveness and potential of water lettuce (Pistia stratiotes L.) in removing nutrients including nitrogen (N) and phosphorus (P) from stormwater in the constructed water detention systems before it is discharged into the St. Lucie Estuary, an important surface water system in Florida, using phytoremediation technologies. In this study, water lettuce (P. stratiotes) was planted in the treatment plots of two stormwater detention ponds (East and West Ponds) in 2005-2007 and water samples from both treatment and control plots were weekly collected and analyzed for water quality properties including pH, electrical conductivity, turbidity, suspended solids, and nutrients (N and P). Optimum plant density was maintained and plant samples were collected monthly and analyzed for nutrient contents. Water quality in both ponds was improved, as evidenced by decreases in water turbidity, suspended solids, and nutrient concentrations. Water turbidity was decreased by more than 60%. Inorganic N (NH(4) (+) and NO(3) (-)) concentrations in treatment plots were more than 50% lower than those in control plots (without plant). Reductions in both PO(4) (3-) and total P were approximately 14-31%, as compared to the control plots. Water lettuce contained average N and P concentrations of 17 and 3.0 g kg(-1), respectively, and removed 190-329 kg N ha(-1) and 25-34 kg P ha(-1) annually. Many aquatic plants have been used to remove nutrients from eutrophic waters but water lettuce proved superior to most other plants in nutrient removal efficiency, owing to its rapid growth and high biomass yield potential. However, the growth and nutrient removal potential are affected by many

THE FARMING AND MARKETING OF ORGANIC LETTUCE: STUDY AT BOBOSAN VILLAGE, KEDUNGBANTENG SUB-DISTRICT, BANYUMAS

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Irene Kartika Eka Wijayanti

2017-09-01

Full Text Available Banyumas has great potential as a producer of organic lettuce in term of condition of natural, human resources and availability of market. The centre producer of organic lettuce is located in district of Kedungbanteng, and managed by farmers group "abdi tani". The aim of this study is to analyze: 1. The cost and income farming of organic lettuce; 2. Financial feasibility of organic lettuce farm; 3. The channel and structure of organic lettuce market. Processing and data analysis performed qualitatively and quantitatively. The data used is to the production and marketing of organic lettuce in period of June-July 2016. Quantitative analysis performed using analysis of cost, farm income, and R/C. Qualitative analysis was conducted to determine the channel and structure of organic lettuce market. The results showed that organic lettuce farm income generating positive value and the value of R/C is greater than one (R/C >1, the farming is profitable and feasible. Organic lettuce marketing channels through the use of one channel, such farmers, traders, retailers (supermarket. Farmers faced monopsony market structure, while traders and retailers deal with oligopoly one

Comparison of Proteome Response to Saline and Zinc Stress in Lettuce

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Luigi eLucini

2015-04-01

Full Text Available Zinc salts occurring in soils can exert an osmotic stress toward plants. However, being zinc a heavy metal, some more specific effects on plant metabolisms can be forecast. In this work, lettuce has been used as a model to investigate salt and zinc stresses at proteome level through a shotgun tandem MS proteomic approach. The effect of zinc stress in lettuce, in comparison with NaCl stress, was evaluated to dissect between osmotic/oxidative stress-related effects, from those changes specifically related to zinc.The analysis of proteins exhibiting a fold change of 3 as minimum (on log 2 normalized abundances, revealed the involvement of photosynthesis (via stimulation of chlorophyll synthesis and enhanced role of photosystem I as well as stimulation of photophosphorylation. Increased glycolytic supply of energy substrates and ammonium assimilation (through formation of glutamine synthetase were also induced by zinc in soil. Similarly, protein metabolism (at both transcriptional and ribosomal level, heat shock proteins and proteolysis were affected. According to their biosynthetic enzymes, hormones appear to be altered by both the treatment and the time point considered: ethylene biosynthesis was enhanced, while production of abscisic acid was up-regulated at the earlier time point to decrease markedly and gibberellins were decreased at the later one.Besides aquaporin PIP2 synthesis, other osmotic/oxidative stress related compounds were enhanced under zinc stress, i.e. proline, hydroxycinnamic acids, ascorbate, sesquiterpene lactones and terpenoids biosynthesis.Although the proteins involved in the response to zinc stress and to salinity were substantially the same, their abundance changed between the two treatments. Lettuce response to zinc was more prominent at the first sampling point, yet showing a faster adaptation than under NaCl stress. Indeed, lettuce plants showed an adaptation after 30 days of stress, in a more pronounced way in the case

Effect of gamma irradiation on microbial quality of minimally processed carrot and lettuce: A case study in Greater Accra region of Ghana

Science.gov (United States)

Frimpong, G. K.; Kottoh, I. D.; Ofosu, D. O.; Larbi, D.

2015-05-01

The effect of ionizing radiation on the microbiological quality on minimally processed carrot and lettuce was studied. The aim was to investigate the effect of irradiation as a sanitizing agent on the bacteriological quality of some raw eaten salad vegetables obtained from retailers in Accra, Ghana. Minimally processed carrot and lettuce were analysed for total viable count, total coliform count and pathogenic organisms. The samples collected were treated and analysed for a 15 day period. The total viable count for carrot ranged from 1.49 to 14.01 log10 cfu/10 g while that of lettuce was 0.70 to 8.5 7 log10 cfu/10 g. It was also observed that total coliform count for carrot was 1.46-7.53 log10 cfu/10 g and 0.14-7.35 log10 cfu/10 g for lettuce. The predominant pathogenic organisms identified were Bacillus cereus, Cronobacter sakazakii, Staphylococcus aureus, and Klebsiella spp. It was concluded that 2 kGy was most effective for medium dose treatment of minimally processed carrot and lettuce.

Determination of elemental concentrations in environmental plant samples by instrumental neutron activation analysis

International Nuclear Information System (INIS)

Datta, J.; Chowdhury, D.P.; Verma, R.; Reddy, A.V.R.

2012-01-01

The intake of leafy vegetables in daily diet is very important to meet our nutritional needs. Vegetables provide the essential elements which are necessary and recommended for human growth. However, due to rapid industrialization and urbanization our environment becomes polluted and this affects the normal growth of agricultural products and composition of environmental species. The elemental concentrations present in the environmental samples are good indicators to assess the toxicological levels due to pollution affects. In the present work we have analysed several vegetable plant samples by instrumental neutron activation analysis to determine the elemental concentrations at major, minor and trace levels. The leafy vegetables like spinach, red leafy vegetable, pui, gourd leaf, lettuce and katoua were chosen as these are extensively consumed by local people in eastern part of India. We have determined 15 elements in the above mentioned vegetable samples and some of these are essential elements and some are toxic elements. It was found that Na and K were present as major elements, Fe and Zn as minor elements and As, Ce, Cr, Co, La, Mo, Rb, Sc, Sm, Sr as trace elements. The concentration level of Cr was found to be higher than that of recommended value certified by WHO and National environment quality control for human consumption. The validation of our analytical results have been performed by the Z-score tests through the determination of concentrations of the elements of interest in certified reference materials. (author)

DNA analysis in three populations of African spinach (Basella spp.)

Energy Technology Data Exchange (ETDEWEB)

Grasso, G; Van Duren, M; Lee, K S; Morpurgo, R [Agriculture and Biotechnology Lab., International Atomic Energy Agency, Seiberdorf (Austria)

1997-07-01

African spinach (Basella spp.) is an important vegetable in West Africa, and was introduced by early colonialists. Its alien origin is supported by its narrow genetic variability. Flowcytometry and RAPD polymorphism were used to investigate genetic variation in three populations of Basella - `Congo native`, `Cong domesticated`, and an introduced cultivar, `Sri Lanka` from Sri Lanka. Normal spinach (Spinacia oleracea) cv. `Prince F{sub 1} Hybrid` was used to test sensitivity and to verify detection of genetic variation. Nuclei were isolated from young leaves of Basella, stained with DAPI and ethidium bromide, and ploidy level and total DNA content were determined by using a flowcytometer. The two sexually propagated populations, `Cong domesticated` and `Sri Lanka` showed very low amount of genetic variation as revealed by RAPD analysis; the third population `Congo native` showed a limited amount of polymorphism. (author). 8 refs, 1 fig., 2 tabs.

Evaluation of Lettuce Germplasm Resistance to Gray Mold Disease for Organic Cultivations

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Chang Ki Shim

2014-03-01

Full Text Available This study was conducted to evaluate the resistance of 212 accessions of lettuce germplasm to gray mold disease caused by Botrytis cinerea. The lettuce germplasm were composed of five species: Lactuca sativa (193 accessions, L. sativa var. longifolia (2 accessions, L. sativa var. crispa (2 accessions, L. saligna (2 accessions, and L. serriola (1 accession; majority of these originated from Korea, Netherlands, USA, Russia, and Bulgaria. After 35 days of spray inoculation with conidial suspension (3×10⁷ conidia/ml of B. cinerea on the surface of lettuce leaves, tested lettuce germplasm showed severe symptoms of gray mold disease. There were 208 susceptible accessions to B. cinerea counted with 100% of disease incidence and four resistant accessions, IT908801, K000598, K000599, and K021055. Two moderately resistant accessions of L. sativa, K021055 and IT908801, showed 20% of disease incidence of gray mold disease at 45 days after inoculation; and two accessions of L. saligna, K000598 and K000599, which are wild relatives of lettuce germplasm with loose-leaf type, showed complete resistance to B. cinerea. These four accessions are candidates for breeding lettuce cultivars resistant to gray mold disease.

Alternative sanitization methods for minimally processed lettuce in comparison to sodium hypochlorite

Directory of Open Access Journals (Sweden)

Mara Lígia Biazotto Bachelli

2013-09-01

Full Text Available Lettuce is a leafy vegetable widely used in industry for minimally processed products, in which the step of sanitization is the crucial moment for ensuring a safe food for consumption. Chlorinated compounds, mainly sodium hypochlorite, are the most used in Brazil, but the formation of trihalomethanes from this sanitizer is a drawback. Then, the search for alternative methods to sodium hypochlorite has been emerging as a matter of great interest. The suitability of chlorine dioxide (60 mg L-1/10 min, peracetic acid (100 mg L-1/15 min and ozonated water (1.2 mg L-1 /1 min as alternative sanitizers to sodium hypochlorite (150 mg L-1 free chlorine/15 min were evaluated. Minimally processed lettuce washed with tap water for 1 min was used as a control. Microbiological analyses were performed in triplicate, before and after sanitization, and at 3, 6, 9 and 12 days of storage at 2 ± 1 ºC with the product packaged on LDPE bags of 60 µm. It was evaluated total coliforms, Escherichia coli, Salmonella spp., psicrotrophic and mesophilic bacteria, yeasts and molds. All samples of minimally processed lettuce showed absence of E. coli and Salmonella spp. The treatments of chlorine dioxide, peracetic acid and ozonated water promoted reduction of 2.5, 1.1 and 0.7 log cycle, respectively, on count of microbial load of minimally processed product and can be used as substitutes for sodium hypochlorite. These alternative compounds promoted a shelf-life of six days to minimally processed lettuce, while the shelf-life with sodium hypochlorite was 12 days.

Dissipation and Residues of Pyrethrins in Leaf Lettuce under Greenhouse and Open Field Conditions.

Science.gov (United States)

Pan, Lixiang; Feng, Xiaoxiao; Zhang, Hongyan

2017-07-21

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 = 5). Evaluation of dissipation and final residues of pyrethrins in leaf lettuce were determined at six different locations, including the open field, as well as under greenhouse conditions. The initial concentration of pyrethrins in greenhouse (0.57 mg/kg) was higher than in open field (0.25 mg/kg) and the half-life for pyrethrins disappearance in field lettuce (0.7 days) was less than that greenhouse lettuce (1.1 days). Factors such as rainfall, solar radiation, wind speed, and crop growth rate are likely to have caused these results. The final residue in leaf lettuce was far below the maximum residue limits (MRLs) (1 mg/kg established by the European Union (EU), Australia, Korea, Japan).

Production system and harvesting stage influence on nitrate content and quality of butterhead lettuce

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Siti Fairuz Yosoff

2015-01-01

Full Text Available Leafy vegetables such as lettuce grown under different production systems may accumulate different concentrations of nitrate which may reach to the levels potentially toxic to humans. Moreover, nitrate accumulation varies in various plant parts and physiological age of the plant. Therefore, to determine the effect of production system and harvesting stage on nitrate accumulation and quality of butterhead lettuce, a study was conducted considering two lettuce production systems namely hydroponic and organic, and four different harvesting stages such as 35, 38, 41 and 44 days after transplanting (DAT. The experimental design was complete randomized design (CRD with four replications. Hydroponic and organic systems performed similar in terms of yield, quality and nitrate content of butterhead lettuce. Delaying harvesting can not only increase yield but also can minimize nitrate accumulation and health hazard risk as well. Delay in harvesting stage may result in quality deterioration of lettuce and increased production cost. Thus, a compromise is necessary to consider 41 DAT as the optimum stage to harvest butterhead lettuce with significantly higher reduction of nitrate content in both outer adult leaf blades and young leaves of hydroponic lettuce. Fresh weight, firmness and color of butterhead lettuce at this stage were still acceptable.

Antioxidant capacity and contents of phenols, ascorbic acid, β-carotene and lycopene in lettuce

Directory of Open Access Journals (Sweden)

Zdravković Jasmina M.

2014-01-01

Full Text Available The antioxidant activity of three lettuce varieties (Lactuca sativa L. Emerald, Vera and Neva, cultivated in two kinds of protected spaces, a glasshouse and a plastic greenhouse, under controlled conditions, was determined. The content of antioxidant compounds: total phenols, flavonoids, L-ascorbic acid, ß-carotene and lycopene, were determined in ethanolic extracts of the lettuce with spectrophotometric methods. The largest content of total phenols (78.98 ± 0.67 mg GAE/g of dry extract was found in ethanolic extract of the lettuce variety Neva cultivated in a plastic greenhouse, whereas the largest content of flavonoids (35.45 ± 0.95 mg RU/g of dry extract was displayed in the lettuce Emerald cultivated in a glasshouse. It was observed that the lettuce cultivated in the glasshouse contained a somewhat higher content of L-ascorbic acid than the lettuce same variety from plastic greenhouse. The content of lycopene in the examined lettuce is negligible, and the content of ß-carotene is low. On the other hand, the high content of phenolic components causes favourable antioxidant properties found in all varieties of examined lettuce. [Projekat Ministarstva nauke Republike Srbije, br. TR 31059: A new concept in breeding vegetable cultivars and hybrids designed for sustainable growing systems using biotechnological methods

Spinach as a source of carotenoids, folate and antioxidant activity

NARCIS (Netherlands)

Castenmiller, J.J.M.

2000-01-01

Fruits and vegetables are generally considered important contributors to a healthy diet and an increased intake of fruits and vegetables is related to a decreased risk of cancers, cardiovascular disease, and other diseases. In this thesis two aspects of spinach, a dark-green, leafy

Simulation of gamma-ray irradiation of lettuce leaves in a 137Cs irradiator using MCNP

International Nuclear Information System (INIS)

Kim, Jongsoon; Moreira, Rosana G.; Braby, Leslie A.

2010-01-01

Ionizing radiation effectively reduces the number of common microbial pathogens in fresh produce. However, the efficacy of the process for pathogens internalized into produce tissue is unknown. The objective of this study was to understand gamma irradiation of lettuce leaf structure exposed in a 137 Cs irradiator using MCNP. The simulated 137 Cs irradiator is a self-shielded device, and its geometry and sources are described in the MCNP input file. When the irradiation chamber is filled with water, lower doses are found at the center of the irradiation volume and the dose uniformity ratio (maximum dose/minimum dose) is 1.76. For randomly oriented rectangular lettuce leaf segments in the irradiation chamber, the dose uniformity ratio is 1.25. It shows that dose uniformity in the Cs irradiator is strongly dependent of the density of the sample. To understand dose distribution inside the leaf, we divided a lettuce leaf into a low density (flat) region (0.72 g/cm 3 ) and high density (rib) region (0.86 g/cm 3 ). Calculated doses to the rib are 61% higher than doses to the flat region of the leaf. This indicates that internalized microorganisms can be inactivated more easily than organisms on the surface. This study shows that irradiation can effectively reduce viable microorganism internalized in lettuce. (author)

Rapid identification of lettuce seed germination mutants by bulked segregant analysis and whole genome sequencing.

Science.gov (United States)

Huo, Heqiang; Henry, Isabelle M; Coppoolse, Eric R; Verhoef-Post, Miriam; Schut, Johan W; de Rooij, Han; Vogelaar, Aat; Joosen, Ronny V L; Woudenberg, Leo; Comai, Luca; Bradford, Kent J

2016-11-01

Lettuce (Lactuca sativa) seeds exhibit thermoinhibition, or failure to complete germination when imbibed at warm temperatures. Chemical mutagenesis was employed to develop lettuce lines that exhibit germination thermotolerance. Two independent thermotolerant lettuce seed mutant lines, TG01 and TG10, were generated through ethyl methanesulfonate mutagenesis. Genetic and physiological analyses indicated that these two mutations were allelic and recessive. To identify the causal gene(s), we applied bulked segregant analysis by whole genome sequencing. For each mutant, bulked DNA samples of segregating thermotolerant (mutant) seeds were sequenced and analyzed for homozygous single-nucleotide polymorphisms. Two independent candidate mutations were identified at different physical positions in the zeaxanthin epoxidase gene (ABSCISIC ACID DEFICIENT 1/ZEAXANTHIN EPOXIDASE, or ABA1/ZEP) in TG01 and TG10. The mutation in TG01 caused an amino acid replacement, whereas the mutation in TG10 resulted in alternative mRNA splicing. Endogenous abscisic acid contents were reduced in both mutants, and expression of the ABA1 gene from wild-type lettuce under its own promoter fully complemented the TG01 mutant. Conventional genetic mapping confirmed that the causal mutations were located near the ZEP/ABA1 gene, but the bulked segregant whole genome sequencing approach more efficiently identified the specific gene responsible for the phenotype. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Selectivity of thiobencarb between two lettuce (Lactuca sativa, L.) cultivars

International Nuclear Information System (INIS)

Reiners, S.

1987-01-01

Thiobencarb [S-(4-chlorobenzyl)N,N-diethylthiocarbamate] was examined for weed control on muck grown lettuce. Weed control results were erratic though differential lettuce tolerance was observed in the field. This led to the testing of five lettuce cultivars for tolerance to the herbicide. Of the five lettuce cultivars evaluated, two were selected with the widest tolerance differences: Great Lakes 366 (GLA) (tolerant) and Dark Green Boston (BOS) (susceptible). Studies examining the mechanism of thiobencarb tolerance were conducted with these two cultivars. Within four days after the addition of thiobencarb to the nutrient solution, BOS had significant reductions in the foliar dry weight. In addition, growth abnormalities including fused leaves were observed, indicating inhibition early in leaf development. Greater amounts of 14 C-thiobencarb were absorbed from nutrient solution by BOS, likely due to a significantly greater root system at the time of treatment. The greater uptake and accumulation of 14 C-label in the leaves, as well as significantly greater amounts of unmetabolized 14 C-thiobencarb in the foliage of BOS may account for the selectivity observed. A thiobencarb sulfoxide was not identified in these studies. This indicates that the metabolism of thiobencarb in lettuce differs from other members of the thiocarbamate family of herbicides

Incidence of Lettuce mosaic virus in lettuce and its detection by polyclonal antibodies produced against recombinant coat protein expressed in Escherichia coli.

Science.gov (United States)

Sharma, Prachi; Sharma, Susheel; Singh, Jasvir; Saha, Swati; Baranwal, V K

2016-04-01

Lettuce mosaic virus (LMV), a member of the genus Potyvirus of family Potyviridae, causes mosaic disease in lettuce has recently been identified in India. The virus is seed borne and secondary infection occurs through aphids. To ensure virus freedom in seeds it is important to develop diagnostic tools, for serological methods the production of polyclonal antibodies is a prerequisite. The coat protein (CP) gene of LMV was amplified, cloned and expressed using pET-28a vector in Escherichia coli BL21DE3 competent cells. The LMV CP was expressed as a fusion protein containing a fragment of the E. coli His tag. The LMV CP/His protein reacted positively with a commercial antiserum against LMV in an immunoblot assay. Polyclonal antibodies purified from serum of rabbits immunized with the fusion protein gave positive results when LMV infected lettuce (Lactuca sativa) was tested at 1:1000 dilution in PTA-ELISA. These were used for specific detection of LMV in screening lettuce accessions. The efficacy of the raised polyclonal antiserum was high and it can be utilized in quarantine and clean seed production. Copyright © 2016 Elsevier B.V. All rights reserved.

A comparison of nitrate level in spinach grown both under different densities in aquaponic system and under natural growth conditions

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Ştefan Mihai PETREA

2013-12-01

Full Text Available As bio-integrated systems that link both plants and fish culture, inside aquaponic systems, the processes of ammonia-oxidizing and nitrification in nitrite and nitrate are essential for growth and development of both fish and plants culture biomass. Plants with nearly the same nutritional requirements during their life cycle, like spinach in our case, are recommended to be grown under aquaponic conditions. Although nitrates concentrations up to 200 – 250mg/l are reported to be acceptable for fish growth, in the last years the toxic effect of long term exposure to high nitrate levels on fish and plants cultured biomass were highlighted. The main goal of the present study is to compare the nitrate level of spinach, grown in an aquaponic system, under three plant densities (V1 - 59 plants/m2, V2 - 48plants/m2 and V3 – 39 plants/m2. The second objective is to compare the results obtained, in term of nitrate content, for spinach grown in the integrated rainbow trout – spinach aquaponic system with those of marketable spinach, grown under conventional condition, in the field. The experimental design consists in a recirculating aquaculture system with 12 growing units, mechanical and biological water treatment units and four aquaponic units. Fish were fed with two types of feed with 41% and 50% protein, using 3 different feeding regimes. The results show a higher nitrate level on spinach grown in aquaponic system, compared to the one derived from field culture. Differences were observed also among the three variants grown in aquaponic conditions, under different plant densities. As a conclusion, it can be said that considering the nitrate level, spinach grown in aquaponic system is marketable.

Consórcios alface-cenoura e alface-rabanete sob manejo orgânico Intercropping of lettuce-carrot and lettuce-radish under organic management

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Ailena Sudo Salgado

2006-07-01

Full Text Available Dois experimentos foram conduzidos, por dois anos consecutivos, em Seropédica, RJ, com o objetivo de avaliar o desempenho agronômico dos consórcios das cultivares de alface 'Regina 71' (lisa e 'Verônica' (crespa com cenoura 'Brasília' e rabanete 'Híbrido nº 19', sob manejo orgânico, assim como determinar as quantidades de macronutrientes exportadas. O delineamento experimental usado foi o de blocos ao acaso, com quatro repetições. No primeiro experimento, os tratamentos consistiram de alface crespa em consórcio com cenoura, alface crespa em consórcio com rabanete e os cultivos solteiros. No segundo experimento, usou-se alface lisa em lugar da crespa. Nos consórcios entre cenoura e alface crespa ou lisa, foram observados índices de uso eficiente da terra, superiores a 1,60. Nos consórcios de rabanete com alface, crespa ou lisa, esses índices foram de 1,54 e 1,27, respectivamente. As quantidades de nutrientes extraídas do sistema pelos produtos colhidos foram inferiores aos aportes efetuados, evidenciando a viabilidade de qualquer dos consórcios avaliados.Two experiments were carried out, in two consecutive years, at Seropédica, RJ, Brazil, aiming to evaluate the agronomic performance of intercropping of lettuce cvs. Regina 71 (smooth leaf and Verônica (crisp leaf with carrot (cv. Brasília and radish (cv. Hybrid number 19, under organic management. The amount of nutrients exported from the system by harvesting was also evaluated. The experimental design used was of completely randomized blocks, with four replications. In the first experiment, treatments consisted of lettuce with crisp leaves intercropped with carrot, lettuce with crisp leaves intercropped with radish and sole crops. In the second experiment, lettuce with smooth leaves was used instead of lettuce with crisp leaves. Intercropping of carrot and lettuce, with crisp or smooth leaf, presented land equivalent ratios higher than 1.60. Intercropping of radish and

Abscisic Acid Accumulation in Spinach Leaf Slices in the Presence of Penetrating and Nonpenetrating Solutes 1

Science.gov (United States)

Creelman, Robert A.; Zeevaart, Jan A. D.

1985-01-01

Abscisic acid (ABA) accumulated in detached, wilted leaves of spinach (Spinacia oleracea L. cv Savoy Hybrid 612) and reached a maximum level within 3 to 4 hours. The increase in ABA over that found in detached turgid leaves was approximately 10-fold. The effects of water stress could be mimicked by the use of thin slices of spinach leaves incubated in the presence of 0.6 molar mannitol, a compound which causes plasmolysis (loss of turgor). About equal amounts of ABA were found both in the leaf slices and in detached leaves, whereas 2 to 4 times more ABA accumulated in the medium than in the slices. When spinach leaf slices were incubated with ethylene glycol, a compound which rapidly penetrates the cell membrane causing a decrease in the osmotic potential of the tissue and only transient loss of turgor, no ABA accumulated. Ethylene glycol was not inhibitory with respect to ABA accumulation. Spinach leaf slices incubated in both ethylene glycol and mannitol had ABA levels similar to those found when slices were incubated with mannitol alone. Increases similar to those found with mannitol also occurred when Aquacide III, a highly purified form of polyethylene glycol, was used. Aquacide III causes cytorrhysis, a situation similar to that found in wilted leaves. Thus, it appears that loss of turgor is essential for ABA accumulation. When spinach leaf slices were incubated with solutes which are supposed to disturb membrane integrity (KHSO3, 2-propanol, or KCl) no increase in ABA was observed. These data indicate that, with respect to the accumulation of ABA, mannitol caused a physical stress (loss of turgor) rather than a chemical stress (membrane damage). PMID:16664022

Methodology for determination of benzimidazolic fungicides residues in strawberry and lettuce by HPLC-DAD

International Nuclear Information System (INIS)

Dangond Araujo, Jose Jairo; Guerrero dallos, Jairo Arturo

2006-01-01

systemic fungicides like benzimidazolic compounds are used to protect several crops of fruits and vegetables. in this work a new method for analysis of Benomyl, carbendazim and thiabendazol in strawberry and lettuce by high performance liquid chromatography with diode array detector (HPLC-DAD) was validated. benomyl residues were determined after its conversion to carbendazim. pesticide residues were extracted from strawberry and lettuce samples with ethyl acetate and these extracts were cleaned up by gel permeation chromatography (GPC). final determination was carried out by HPLC-DAD in reverse phase column. the method is selective, specific, precise and accurate. the calibration curves show linearity over concentration range of 1.24 to 6.19 mg/kg, with detection limits of 0.40 and 0.27 mg/kg and quantification limits of 1.35 and 0.81 mg/kg for carbendazim and thiabendazole respectively. the recovery experiments yielding averages of 90 %. n o residues of these compounds were found in collected samples from specific areas of Cundinamarca, Colombia

Effect of Salt Stress on Morphological Traits of Lettuce Genotypes (Lactuca Sativa L.

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maryam zare

2017-02-01

Full Text Available Introduction: The recognition of salt tolerant plants is important as a result ofincreasing saline lands in Iran and world. Cultivation of plants in hydroponic environment is a reliable and economical method in order to select the salt tolerant plant. Salt stress can effect on plant growth and development by ion toxicity, ionic disturb the balance and osmotic potential. Lettuce is one of the most important vegetable crops. This plant is one of the most important leafy vegetables which is used for salad and fresh marketing, also some types of this vegetable is used in baked type. The aim of this study was to investigate the genetic diversity of lettuce genotypes undersalt stress in the hydroponic system. Materials and Methods: To assess response of lettuce seedlings to salt stress, a factorial experiment was conducted in a completely randomized design with three replications at Biotechnology Research Institute for hydroponic cultivation of Zabol. In this experiment, the effects of three salinity levels (0, 2 and 4 dS/m on morphological characteristics of 15 lettuce genotypes were evaluated. The seeds were sterilized for ten seconds in ethanol 96% and then 15% sodium hypochlorite solution for 50 seconds, then rinsed several times with distilled water, then disinfected seeds were cultured in plastic pots containing coco peat and perlite. After …days plants were transferred to hydroponic system containing Hoagland solution. Collected data were analyzed and means comparisons were made using LSD by SAS software. Results and Discussion: The results showed that salinity has a significant effect on seedling growth of lettuce genotypes (p≤0.01. significant difference between salinity levels and genotype were observed for all traits. Interaction of genotype and salinity for all the traits except root length, plant length and leaf were significant at 1%. Based on the results, the greatest root length was belong to Esfahan Varzaneh leafy lettuce and

Effect of Salt Stress on Morphological Traits of Lettuce Genotypes (Lactuca Sativa L.

Directory of Open Access Journals (Sweden)

maryam zare

2017-09-01

Full Text Available Introduction: The recognition of salt tolerant plants is important as a result ofincreasing saline lands in Iran and world. Cultivation of plants in hydroponic environment is a reliable and economical method in order to select the salt tolerant plant. Salt stress can effect on plant growth and development by ion toxicity, ionic disturb the balance and osmotic potential. Lettuce is one of the most important vegetable crops. This plant is one of the most important leafy vegetables which is used for salad and fresh marketing, also some types of this vegetable is used in baked type. The aim of this study was to investigate the genetic diversity of lettuce genotypes undersalt stress in the hydroponic system. Materials and Methods: To assess response of lettuce seedlings to salt stress, a factorial experiment was conducted in a completely randomized design with three replications at Biotechnology Research Institute for hydroponic cultivation of Zabol. In this experiment, the effects of three salinity levels (0, 2 and 4 dS/m on morphological characteristics of 15 lettuce genotypes were evaluated. The seeds were sterilized for ten seconds in ethanol 96% and then 15% sodium hypochlorite solution for 50 seconds, then rinsed several times with distilled water, then disinfected seeds were cultured in plastic pots containing coco peat and perlite. After …days plants were transferred to hydroponic system containing Hoagland solution. Collected data were analyzed and means comparisons were made using LSD by SAS software. Results and Discussion: The results showed that salinity has a significant effect on seedling growth of lettuce genotypes (p≤0.01. significant difference between salinity levels and genotype were observed for all traits. Interaction of genotype and salinity for all the traits except root length, plant length and leaf were significant at 1%. Based on the results, the greatest root length was belong to Esfahan Varzaneh leafy lettuce and

Spinach seed quality - potential for combining seed size grading and chlorophyll flourescence sorting

DEFF Research Database (Denmark)

Deleuran, Lise Christina; Olesen, Merete Halkjær; Boelt, Birte

2013-01-01

might therefore improve the establishment of spinach for producers. Spinach seeds were harvested at five different times (H1, H2, H3, H4 and H5) starting 3 weeks before estimated optimum harvest time. The harvested seeds were sorted according to chlorophyll fluorescence (CF) and seed size. Two harvest.......5–3.25 mm size seeds had germinated on day 3 than both their larger and smaller counterparts at the later time of harvest (H4). Seeds with a diameter below 2.5 mm displayed the lowest MGT. Commercially, the use of chlorophyll fluorescence (CF)-sorted seeds, in combination with seed size sorting, may provide...

The Inlfuence of Biochar on Growth of Lettuce and Potato

Institute of Scientific and Technical Information of China (English)

Kalika P. Upadhyay; Doug George; Roger S. Swift; Victor Galea

2014-01-01

Pot experiments were conducted in a glasshouse to determine the growth pattern of lettuce, true potato seedlings (TPS) and single node cuttings of TPS in response to biochar. The treatments were arranged in a randomized complete block design with 5 treatments (0, 10, 30, 50 and 100 t ha-1) of biochar from greenwaste with 5 replications in lettuce, 10 in TPS and 5 in single node cuttings of TPS. The observations recorded on growth parameters showed that biochar had signiifcant effect on growth of lettuce but no consistent effect on growth of TPS and single node cuttings. Among the biochar rates, 30 t ha-1 had the greatest inlfuence on overall growth of lettuce. The pH and electrical conductivity increased as the biochar rates increased in all experiments. These results provide an avenue for soil management system by using biochar as an amendment in horticultural crops. However, their veriifcation in the ifeld is important for speciifc recommendations.

Bioavailability of sodium nitrite from an aqueous solution in healthy adults.

NARCIS (Netherlands)

Hunault, C.C.; van Velzen, A.G.; Sips, A.J.; Schothorst, R.C.; Meulenbelt, J.|info:eu-repo/dai/nl/079479227

2009-01-01

Nitrate intake in humans is high through intake of vegetables such as beets, lettuce, and spinach. Nitrate itself is a compound of low toxicity but its metabolite, nitrite, formed by bacteria in the oral cavity and gastrointestinal tract, has been suspected of potential carcinogenic effects. Nitrite

Effect of Nd3+ ion on carboxylation activity of ribulose-1,5-bisphosphate carboxylase/oxygenase of spinach

International Nuclear Information System (INIS)

Liu Chao; Hong Fashui; Wu Kang; Ma, Hong-bing; Zhang Xueguang; Hong Chengjiao; Wu Cheng; Gao Fengqing; Yang Fan; Zheng Lei; Wang Xuefeng; Liu Tao; Xie Yaning; Xu Jianhua; Li Zhongrui

2006-01-01

Neodymium (Nd), as a member of rare earth elements, proved to enhance the photosynthesis rate and organic substance accumulation of spinach through the increase in carboxylation activity of Rubisco. Although the oxygenase activity of spinach Rubisco was slightly changed with the Nd 3+ treatment, the specific factor of Rubisco was greatly increased. It was partially due to the promotion of Rubisco activase (R-A) activity but mainly to the formation of Rubisco-Rubisco activase super-complex, a heavier molecular mass protein (about 1200 kD) comprising both Rubisco and Rubisco activase. This super-complex was found during the extraction procedure of Rubisco by the gel electrophoresis and Western-blot studies. The formation of Rubisco-R-A super-complex suggested that the secondary structure of the protein purified from the Nd 3+ -treated spinach was different from that of the control. Extended X-ray absorption fine structure study of the 'Rubisco' purified from the Nd 3+ -treated spinach revealed that Nd was bound with four oxygen atoms and two sulfur atoms of amino acid residues at the Nd-O and Nd-S bond lengths of 2.46 and 2.89 A, respectively

Contribution of vitamin K1 to the electron spin polarization in spinach photosystem I

International Nuclear Information System (INIS)

Rustandi, R.R.; Snyder, S.W.; Feezel, L.L.; Michalski, T.J.; Norris, J.R.; Thurnauer, M.C.; Biggins, J.

1990-01-01

The electron spin polarized (ESP) electron paramagnetic resonance (EPR) signal observed in spinach photosystem I (PSI) particles was examined in preparations depleted of vitamin K1 by solvent extraction and following biological reconstitution by the quinone. The ESP EPR signal was not detected in the solvent-extracted PSI sample but was restored upon reconstitution with either protonated or deuterated vitamin K1 under conditions that also restored electron transfer to the terminal PSI acceptors. Reconstitution using deuterated vitamin K1 resulted in a line narrowing of the ESP EPR signal, supporting the conclusion that the ESP EPR signals in the reconstituted samples arise from a radical pair consisting of the oxidized PSI primary donor, P700+, and reduced vitamin K1

Efficient and stable transformation of Lactuca sativa L. cv. Cisco (lettuce) plastids.

Science.gov (United States)

Kanamoto, Hirosuke; Yamashita, Atsushi; Asao, Hiroshi; Okumura, Satoru; Takase, Hisabumi; Hattori, Masahira; Yokota, Akiho; Tomizawa, Ken-Ichi

2006-04-01

Transgenic plastids offer unique advantages in plant biotechnology, including high-level foreign protein expression. However, broad application of plastid genome engineering in biotechnology has been largely hampered by the lack of plastid transformation systems for major crops. Here we describe the development of a plastid transformation system for lettuce, Lactuca sativa L. cv. Cisco. The transforming DNA carries a spectinomycin-resistance gene (aadA) under the control of lettuce chloroplast regulatory expression elements, flanked by two adjacent lettuce plastid genome sequences allowing its targeted insertion between the rbcL and accD genes. On average, we obtained 1 transplastomic lettuce plant per bombardment. We show that lettuce leaf chloroplasts can express transgene-encoded GFP to approximately 36% of the total soluble protein. All transplastomic T0 plants were fertile and the T1 progeny uniformly showed stability of the transgene in the chloroplast genome. This system will open up new possibilities for the efficient production of edible vaccines, pharmaceuticals, and antibodies in plants.

Prevalence of Lettuce mosaic virus - common strain on three lettuce producing areas from São Paulo State Prevalência da estirpe comum de Lettuce mosaic virus em três regiões produtoras de alface do estado de São Paulo

Directory of Open Access Journals (Sweden)

Ana Carolina Firmino

2008-06-01

Full Text Available LMV is one of the most important pathogens of lettuce worldwide. Based on their ability to overcome the resistance genes mo1¹ and mo1² in lettuce, isolates can be divided in two types: LMV-Most, which can infect and are seed-borne in cultivars containing the mo1 gene and LMV-Common, which do not cause symptoms on these cultivars and are seed transmitted only in susceptible cultivars. To evaluate the occurrence of these two types of LMV isolates, a survey was carried out during 2002-2005 in three lettuce production areas from São Paulo State. Total RNA was used for the diagnosis of LMV isolates by RT-PCR using universal primers for the variable N-terminus of the capsid protein, in the 3' end of the genome. Positives samples were analyzed by a second RT-PCR using specifics primers for LMV-Most isolates designed to amplify a fragment from the central region (CI-VPg of the genome. A total of 1362 samples showing mosaic symptoms were collected and 504 (37.29 % were positives for LMV. On susceptible lettuce cultivars, LMV-Common was prevalent (77.3%. LMV-Most was found frequently associated with tolerant (mo1¹ lettuce cultivars. Susceptible cultivars correspond today for most of the area of lettuce production. So, despite the ability of LMV-Most isolates to overcome the resistance provided by the recessive mo1¹ gene, they are not prevalent in the conditions of São Paulo State.O LMV ocorre em todo o mundo e é considerado um dos patógenos mais importantes para a cultura da alface. De acordo com a habilidade em contornar os genes de resistência mo1¹ e mo1² encontrados em alface, os isolados de LMV podem ser dividos em dois sub-grupos: LMV-Most, capazes de contornar a resistência propiciada por estes genes e de serem transmitidos pela semente nestas cutivares, e LMV-Common, que não são capazes de causar sintomas nestes cultivares, além de serem transmitidos pela semente somente em cultivares suscetíveis. Para avaliar a ocorrência destes

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce.

Science.gov (United States)

Schreiter, Susanne; Ding, Guo-Chun; Heuer, Holger; Neumann, Günter; Sandmann, Martin; Grosch, Rita; Kropf, Siegfried; Smalla, Kornelia

2014-01-01

The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for 10 years under the same agricultural management to reveal differences directly linked to the soil type and not influenced by other factors such as climate or cropping history. Bulk soil and rhizosphere samples were collected 3 and 7 weeks after planting. The analysis of 16S rRNA gene fragments amplified from total community DNA by denaturing gradient gel electrophoresis and pyrosequencing revealed soil type dependent differences in the bacterial community structure of the bulk soils and the corresponding rhizospheres. The rhizosphere effect differed depending on the soil type and the plant growth developmental stage. Despite the soil type dependent differences in the bacterial community composition several genera such as Sphingomonas, Rhizobium, Pseudomonas, and Variovorax were significantly increased in the rhizosphere of lettuce grown in all three soils. The number of rhizosphere responders was highest 3 weeks after planting. Interestingly, in the soil with the highest numbers of responders the highest shoot dry weights were observed. Heatmap analysis revealed that many dominant operational taxonomic units were shared among rhizosphere samples of lettuce grown in diluvial sand, alluvial loam, and loess loam and that only a subset was increased in relative abundance in the rhizosphere compared to the corresponding bulk soil. The findings of the study provide insights into the effect of soil types on the rhizosphere microbiome of lettuce.

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce

Directory of Open Access Journals (Sweden)

Susanne eSchreiter

2014-04-01

Full Text Available The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for ten years under the same agricultural management to reveal differences directly linked to the soil type and not influenced by other factors such as climate or cropping history. Bulk soil and rhizosphere samples were collected three and seven weeks after planting. The analysis of 16S rRNA gene fragments amplified from total community DNA by denaturing gradient gel electrophoresis and pyrosequencing revealed soil type-dependent differences in the bacterial community structure of the bulk soils and the corresponding rhizospheres. The rhizosphere effect differed depending on the soil type and the plant growth developmental stage. Despite the soil type-dependent differences in the bacterial community composition several genera such as Sphingomonas, Rhizobium, Pseudomonas and Variovorax were significantly increased in the rhizosphere of lettuce grown in all three different soils. The number of rhizosphere responders was highest three weeks after planting. Interestingly, in the soil with the highest numbers of responders the highest shoot dry weights were observed. Heatmap analysis revealed that many dominant operational taxonomic units were shared among rhizosphere samples of lettuce grown in diluvial sand, alluvial loam, and loess loam and that only a subset was increased in relative abundance in the rhizosphere compared to the corresponding bulk soil. The findings of the study provide insights into the effect of soil types on the rhizosphere microbiome of lettuce.

Determination of free inositols and other low molecular weight carbohydrates in vegetables.

Science.gov (United States)

Hernández-Hernández, Oswaldo; Ruiz-Aceituno, Laura; Sanz, María Luz; Martínez-Castro, Isabel

2011-03-23

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 eggplant skin, and a glycosyl-inositol in spinach have been identified. chiro-Inositol was found in all vegetables of the Asteraceae family (3.1-32.6 mg 100 g(-1)), whereas scyllo-inositol was detected in those of purple yam, eggplant, artichoke, chicory, escarole, and endive (traces-23.2 mg 100 g(-1)). α-Galactosides, kestose, glucaric acid, and glycosyl-glycerols were also identified and quantified in some of the analyzed vegetables. Considering the bioactivity of most of these compounds, mainly chicory leaves, artichokes, lettuces, and purple yam could constitute beneficial sources for human health.

Rapid cloning and bioinformatic analysis of spinach Y chromosome ...

Indian Academy of Sciences (India)

Rapid cloning and bioinformatic analysis of spinach Y chromosome- specific EST sequences. Chuan-Liang Deng, Wei-Li Zhang, Ying Cao, Shao-Jing Wang, ... Arabidopsis thaliana mRNA for mitochondrial half-ABC transporter (STA1 gene). 389 2.31E-13. 98.96. SP3−12. Betula pendula histidine kinase 3 (HK3) mRNA, ...

Detection of Salmonella Typhimurium on Spinach Using Phage-Based Magnetoelastic Biosensors

Directory of Open Access Journals (Sweden)

Fengen Wang

2017-02-01

Full Text Available Phage-based magnetoelastic (ME biosensors have been studied as an in-situ, real-time, wireless, direct detection method of foodborne pathogens in recent years. This paper investigates an ME biosensor method for the detection of Salmonella Typhimurium on fresh spinach leaves. A procedure to obtain a concentrated suspension of Salmonella from contaminated spinach leaves is described that is based on methods outlined in the U.S. FDA Bacteriological Analytical Manual for the detection of Salmonella on leafy green vegetables. The effects of an alternative pre-enrichment broth (LB broth vs. lactose broth, incubation time on the detection performance and negative control were investigated. In addition, different blocking agents (BSA, Casein, and Superblock were evaluated to minimize the effect of nonspecific binding. None of the blocking agents was found to be superior to the others, or even better than none. Unblocked ME biosensors were placed directly in a concentrated suspension and allowed to bind with Salmonella cells for 30 min before measuring the resonant frequency using a surface-scanning coil detector. It was found that 7 h incubation at 37 °C in LB broth was necessary to detect an initial spike of 100 cfu/25 g S. Typhimurium on spinach leaves with a confidence level of difference greater than 95% (p < 0.05. Thus, the ME biosensor method, on both partly and fully detection, was demonstrated to be a robust and competitive method for foodborne pathogens on fresh products.

Oxygenated phosphine fumigation for control of Nasonovia ribisnigri (Homoptera: Aphididae) on harvested lettuce.

Science.gov (United States)

Liu, Yong-Biao

2012-06-01

Low temperature regular phosphine fumigations under the normal oxygen level and oxygenated phosphine fumigations under superatmospheric oxygen levels were compared for efficacy against the aphid, Nasonovia ribisnigri (Mosley), and effects on postharvest quality of romaine and head lettuce. Low temperature regular phosphine fumigation was effective against the aphid. However, a 3 d treatment with high phosphine concentrations of > or = 2,000 ppm was needed for complete control of the aphid. Oxygen greatly increased phosphine toxicity and significantly reduced both treatment time and phosphine concentration for control of N. ribisnigri. At 1,000 ppm phosphine, 72 h regular fumigations at 6 degrees C did not achieve 100% mortality of the aphid. The 1,000 ppm phosphine fumigation under 60% O2 killed all aphids in 30 h. Both a 72 h regular fumigation with 2,200 ppm phosphine and a 48 h oxygenated fumigation with 1,000 ppm phosphine under 60% O2 were tested on romaine and head lettuce at 3 degrees C. Both treatments achieved complete control of N. ribisnigri. However, the 72 h regular fumigation resulted in significantly higher percentages of lettuce with injuries and significantly lower lettuce internal quality scores than the 48 h oxygenated phosphine fumigation. Although the oxygenated phosphine fumigation also caused injuries to some treated lettuce, lettuce quality remained very good and the treatment is not expected to have a significant impact on marketability of the lettuce. This study demonstrated that oxygenated phosphine fumigation was more effective and less phytotoxic for controlling N. ribisnigri on harvested lettuce than regular phosphine fumigation and is promising for practical use.

Functional metagenomics of Escherichia coli O157:H7 interactions with spinach indigenous microorganisms during biofilm formation.

Directory of Open Access Journals (Sweden)

Michelle Q Carter

Full Text Available The increase in foodborne outbreaks worldwide attributed to fresh fruit and vegetables suggests that produce may serve as an ecological niche for enteric pathogens. Here we examined the interaction of E. coli O157:H7 (EcO157 with spinach leaf indigenous microorganisms during co-colonization and establishment of a mixed biofilm on a stainless steel surface. Stainless steel surface was selected to mimic the surface of produce-processing equipment, where retention of foodborne pathogens such as EcO157 could serve as a potential source for transmission. We observed a positive effect of spinach-associated microbes on the initial attachment of EcO157, but an antagonistic effect on the EcO157 population at the later stage of biofilm formation. Metagenomic analyses of the biofilm community with the GeoChip revealed an extremely diverse community (gene richness, 23409; Shannon-Weiner index H, 9.55. Presence of EcO157 in the mixed biofilm resulted in a significant decrease in the community α-diversity (t test, P<0.05, indicating a putative competition between the pathogen and indigenous spinach microbes. The decrease in the β-diversity of the EcO157-inoculated biofilm at 48 h (ANOVA, P<0.05 suggested a convergent shift in functional composition in response to EcO157 invasion. The success of EcO157 in the mixed biofilm is likely associated with its metabolic potential in utilizing spinach nutrients: the generation time of EcO157 in spinach lysates at 28°C is ~ 38 min, which is comparable to that in rich broth. The significant decrease in the abundance of many genes involved in carbon, nitrogen, and phosphorus cycling in the EcO157-inoculated biofilms (t test, P<0.05 further support our conclusion that competition for essential macronutrients is likely the primary interaction between the EcO157 and indigenous spinach-biofilm species.

[Fast separation and analysis of water-soluble vitamins in spinach by capillary electrophoresis with high voltage].

Science.gov (United States)

Hu, Xiaoqin; You, Huiyan

2009-11-01

In capillary electrophoresis, 0-40 kV (even higher) voltage can be reached by a connecting double-model high voltage power supply. In the article, water-soluble vitamins, VB1, VB2, VB6, VC, calcium D-pantothenate, D-biotin, nicotinic acid and folic acid in vegetable, were separated by using the high voltage power supply under the condition of electrolyte water solution as running buffer. The separation conditions, such as voltage, the concentration of buffer and pH value etc. , were optimized during the experiments. The results showed that eight water-soluble vitamins could be baseline separated in 2.2 min at 40 kV applied voltage, 25 mmol/L sodium tetraborate buffer solution (pH 8.8). The water-soluble vitamins in spinach were quantified and the results were satisfied. The linear correlation coefficients of the water-soluble vitamins ranged from 0.9981 to 0.9999. The detection limits ranged from 0.2 to 0.3 mg/L. The average recoveries ranged from 88.0% to 100.6% with the relative standard deviations (RSD) range of 1.15%-4.13% for the spinach samples.

Genetic map construction and QTL analysis of nitrogen use efficiency in spinach (Spinacia oleracea L.)

OpenAIRE

Chan Navarrete, Jose Rafael; Dolstra, Oene; Kaauwen, van, Martijn; Lammerts van Bueren, Edith T.; Linden, van der, Gerard

2016-01-01

Cultivation of spinach requires high amounts of nitrogen (N), which puts a strain on the environment. A sustainable solution to this problem is to breed for crops with higher N use efficiency (NUE). The aim of this study was to provide tools for molecular breeding and to elucidate the genetic variation of factors contributing to NUE in spinach. A cross was made between two F1 hybrid cultivars contrasting in NUE. Several F1 progeny were self-pollinated and based on evaluation of the F2 generat...

Isolation and chemical characterization of phosphatidyl glycerol from spinach leaves

NARCIS (Netherlands)

Haverkate, E.; Deenen, L.L.M. van

1965-01-01

Pure phosphatidyl glycerol was obtained from spinach leaves after repeated chromatography on silica columns. Ascertainment of the configuration of the hydrolysis products formed by the action of phospholipases C (EC 3.1.4.3) and D (EC 3.1.4.4) demonstrated that this phospholipid is identical with

Postharvest transfer and survival of Salmonella enterica serotype enteritidis on living lettuce.

Science.gov (United States)

Waitt, J A; Kuhn, D D; Welbaum, G E; Ponder, M A

2014-02-01

The potential for postharvest transfer of Salmonella to 'living lettuce' is not well understood. In this study, the transfer of Salmonella enterica Enteritidis (6 log CFU g(-1) ) from worker hands or contaminated roots to leaves of living lettuce was quantified. Transfer rates of Salmonella from contaminated gloves to sequentially handled lettuce heads ranged from 94% to head 1, 82% to head 2 and 69% to head 3. On average, 2.9 ± 0.1 log CFU g(-1) (64%) Salmonella was transferred from inoculated roots to leaves resulting from typical postharvest handling activities for living lettuce. Salmonella persisted on leaves stored at recommended storage temperatures (4°C) and increased 0.5 log CFU g(-1) when stored at temperature abuse conditions (12°C). Salmonella increased 1.6 log CFU g(-1) on roots after 18-day storage at 12°C, emphasizing the need to maintain temperature control to reduce the risk of human illness. Hydroponically grown lettuce packaged in plastic clamshells with intact roots, marketed as 'living lettuce', is increasing in popularity due to its extended shelf life. This study demonstrates the transfer of Salmonella from contaminated worker hands and contaminated roots to leaves where it persisted at 4°C for 18 day. Temperature abuse (12°C) increased Salmonella on roots and leaves. These findings suggest that failure to maintain temperatures below 12°C can pose a risk for consumers purchasing living lettuce at markets where recommended storage temperatures are not maintained. © 2013 The Society for Applied Microbiology.

Concomitant uptake of antimicrobials and Salmonella in soil and into lettuce following wastewater irrigation.

Science.gov (United States)

Sallach, J Brett; Zhang, Yuping; Hodges, Laurie; Snow, Daniel; Li, Xu; Bartelt-Hunt, Shannon

2015-02-01

The use of wastewater for irrigation may introduce antimicrobials and human pathogens into the food supply through vegetative uptake. The objective of this study was to investigate the uptake of three antimicrobials and Salmonella in two lettuce cultivars. After repeated subirrigation with synthetic wastewater, lettuce leaves and soil were collected at three sequential harvests. The internalization frequency of Salmonella in lettuce was low. A soil horizon-influenced Salmonella concentration gradient was determined with concentrations in bottom soil 2 log CFU/g higher than in top soil. Lincomycin and sulfamethoxazole were recovered from lettuce leaves at concentrations as high as 822 ng/g and 125 ng/g fresh weight, respectively. Antimicrobial concentrations in lettuce decreased from the first to the third harvest suggesting that the plant growth rate may exceed antimicrobial uptake rates. Accumulation of antimicrobials was significantly different between cultivars demonstrating a subspecies level variation in uptake of antibiotics in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preventing an increase in Verticillium wilt incidence in spinach seed production

DEFF Research Database (Denmark)

Olesen, Merete Halkjær; Deleuran, Lise Christina; Gislum, René

2014-01-01

A semifield assay was conducted from 2009 to 2011 to distinguish between different preventive methods of reducing Verticillium spp. in spinach seed production. The seed treatments for controlling seed infection levels included Thiram, Signum, Trichoderma harzianum, Gliocladium roseum and Natural II...

High- but not low-intensity light leads to oxidative stress and quality loss of cold-stored baby leaf spinach.

Science.gov (United States)

Glowacz, Marcin; Mogren, Lars M; Reade, John P H; Cobb, Andrew H; Monaghan, James M

2015-07-01

Quality management in the fresh produce industry is an important issue. Spinach is exposed to various adverse conditions (temperature, light, etc.) within the supply chain. The present experiments were conducted to investigate the effect of light conditions (dark, low-intensity light (LL) and high-intensity light (HL)) and photoperiod (6 h HL and 18 h dark) on the quality changes of cold-stored spinach. HL exposure resulted in oxidative stress, causing tissue damage and quality loss as evidenced by increased membrane damage and water loss. The content of total ascorbic acid was reduced under HL conditions. On the other hand, storage of spinach under LL conditions gave promising results, as nutritional quality was not reduced, while texture maintenance was improved. No significant differences, with the exception of nutritional quality, were found between spinach leaves stored under continuous (24 h) low-intensity light (30-35 µmol m(-2) s(-1)) and their counterparts stored under the same light integral over 6 h (130-140 µmol m(-2) s(-1)). LL extended the shelf-life of spinach. The amount of light received by the leaves was the key factor affecting produce quality. Light intensity, however, has to be low enough not to cause excess oxidative stress and lead to accelerated senescence. © 2014 Society of Chemical Industry.

Influence of production time on quality and height of yield of crisp lettuce

International Nuclear Information System (INIS)

Odziemkowski, S.; Gajc-Wolska, J.; Skapski, H.

1998-01-01

The cultivar of crisp lettuce Saladin, was grown in the field in 10 production terms starting from spring to autumn in 1993-95. The highest average weight of head of crisp lettuce was obtained in earlier terms of production. The head weight at the time of harvest depended on the amount of solar radiation during the time of lettuce head formation

Stimulation of lettuce seed germination by ethylene.

Science.gov (United States)

Abeles, F B; Lonski, J

1969-02-01

Ethylene increased the germination of freshly imbibed lettuce (Lactuca sativa L. var. Grand Rapids) seeds. Seeds receiving either red or far-red light or darkness all showed a positive response to the gas. However, ethylene was apparently without effect on dormant seeds, those which failed to germinate after an initial red or far-red treatment. Carbon dioxide, which often acts as a competitive inhibitor of ethylene, failed to clearly reverse ethylene-enhanced seed germination. While light doubled ethylene production from the lettuce seeds, its effect was not mediated by the phytochrome system since both red and far-red light had a similar effect.

Qualidade física, microbiológica e parasitológica de alfaces (Lactuca sativa de diferentes sistemas de cultivo Physical, microbiological and parasitological quality of lettuce (Lactuca sativa from different growing processes

Directory of Open Access Journals (Sweden)

Ligia Regina R. de Santana

2006-06-01

Full Text Available A alface (Lactuca sativa é a hortaliça folhosa mais comercializada no Brasil. Seu baixo valor calórico a qualifica para diversas dietas, o que favorece o seu consumo sob a forma crua, possibilitando a ocorrência de enfermidades intestinais. O objetivo deste trabalho foi realizar uma avaliação física, microbiológica e parasitológica de amostras de alfaces, variedade crespa, provenientes dos sistemas de cultivo orgânico, tradicional e hidropônico, comercializadas nos principais supermercados da cidade de Salvador (BA, no período de setembro de 2003 a junho de 2004. As amostras do cultivo hidropônico apresentaram o menor peso total e da parte bio-comestível, diferindo significativamente (pThe lettuce (Lactuca sativa has economic importance to the people in Brazil. The aim of this study was to carry out a physical, microbiological and parasitological evaluations in the lettuce samples - crisp variety, according to organic, traditional and hydroponics growing processes, commercialized at the supermarkets of the City of Salvador, Bahia, Brazil, collected from September/2003 until June/2004. The hydroponics lettuce samples showed the lowest total and edible part weight; they were inserted into Extra rate quality standard, according to the current legislation, whereas the organic and traditional lettuce samples were inserted into First and Second rate quality standard, respectively. The lettuce samples, independently of the growing process, showed low hygienic conditions, indicated by the presence of parasites of animal or human origin, and high concentration of fecal coliforms; the organic lettuce samples showed the highest frequencies of enteroparasities and fecal coliforms concentration, followed by the traditional and hydroponics lettuce samples. Considering the obtained results, the importance of this kind of food in the transmission of enteroparasities is stressed, as well as the need of actions which improve the sanitary conditions

Effect of gamma irradiation on microbial quality of minimally processed carrot and lettuce: A case study in Greater Accra region of Ghana

International Nuclear Information System (INIS)

Frimpong, G.K.; Kottoh, I.D.; Ofosu, D.O.; Larbi, D.

2015-01-01

The effect of ionizing radiation on the microbiological quality on minimally processed carrot and lettuce was studied. The aim was to investigate the effect of irradiation as a sanitizing agent on the bacteriological quality of some raw eaten salad vegetables obtained from retailers in Accra, Ghana. Minimally processed carrot and lettuce were analysed for total viable count, total coliform count and pathogenic organisms. The samples collected were treated and analysed for a 15 day period. The total viable count for carrot ranged from 1.49 to 14.01 log 10 cfu/10 g while that of lettuce was 0.70 to 8.5 7 log 10 cfu/10 g. It was also observed that total coliform count for carrot was 1.46–7.53 log 10 cfu/10 g and 0.14–7.35 log 10 cfu/10 g for lettuce. The predominant pathogenic organisms identified were Bacillus cereus, Cronobacter sakazakii, Staphylococcus aureus, and Klebsiella spp. It was concluded that 2 kGy was most effective for medium dose treatment of minimally processed carrot and lettuce. - Highlights: • The microbial load on the cut-vegetables was beyond acceptable level for consumption. • The microbial contamination of carrot was found to be higher than that of lettuce. • 2 kGy was most appropriate in treating cut-vegetables for microbial safety

Control of radioactive contamination of food in the country Somogy

International Nuclear Information System (INIS)

Varga, E.; Viragh, I.

1980-01-01

The radioactive contamination of spinach, sorrel, lettuce, animal bones, milk and fish was determined in the period 1961-1978. Peak values were measured in 1963 and 1976. The contamination of plants reached higher levels, however, it did not exceed 25 pCi per g dry weight. (L.E.)

Transfer and expression of the rabbit defensin NP-1 gene in lettuce (Lactuca sativa).

Science.gov (United States)

Song, D; Xiong, X; Tu, W F; Yao, W; Liang, H W; Chen, F J; He, Z Q

2017-01-23

Lettuce (Lactuca sativa L.) is an annual plant of the daisy family, Asteraceae, with high food and medicinal value. However, the crop is susceptible to several viruses that are transmitted by aphids and is highly vulnerable to post-harvest diseases, as well as insect and mammal pests and fungal and bacterial diseases. Here, the rabbit defensin gene NP-1 was transferred into lettuce by Agrobacterium-mediated transformation to obtain a broad-spectrum disease-resistant lettuce. Transgenic lettuce plants were selected and regenerated on selective media. The presence of the NP-1 gene in these plants was confirmed by western blot analyses. Resistance tests revealed native defensin NP-1 expression conferred partial resistance to Bacillus subtilis and Pseudomonas aeruginosa, which suggests new possibilities for lettuce disease resistance.

Concentrating biomass of fermented broccoli (Brassica oleracea) and spinach (Amaranthus sp.) by ultrafiltration for source of organic acids and natural antioxidant

Science.gov (United States)

Aspiyanto, Susilowati, Agustine; Lotulung, Puspa D.; Maryati, Yati

2017-11-01

Organic acids and polyphenol from fermentation of green vegetables by Kombucha culture are novelty functional food to achieve prebiotic and natural antioxidant. Ultrafiltration (UF) mode was performed to concentrate biomass of fermented broccoli (Brassica oleracea L.) and spinach (Amaranthus spp.) at stirrer rotation speed of 200, 300 and 400 rpm, room temperature and trans membrane pressure 40 psia for 30 minutes. Based on total organic acids, experiment activity showed that the best treatment on biomass of fermented broccoli and spinach were reached at stirrer rotation speed of 400 rpm and 300 rpm, respectively. In this condition, fermented broccoli and spinach concentrates gave total acids 0.83 % and 0.81 %, total polyphenol 0.06 % and 0.11 %, reducing sugar 63.95 mg/mL and 20.54 mg/mL, total sugars 2.43 ug/mL and 2.28 ug/mL, total solids 6.42 % and 7.17 %, respectively. Compared with feed, the optimum condition on fermented spinach and broccoli concentrates increased total acids 13.33 % and 10 %, however decreased total polyphenol 34.1 % and 41 %. Identification on monomer from fermented spinach and broccoli at optimum condition on lactic acid were dominated by monomers with molecular weights (MWs) 252.19 and 252.36 Dalton (Da.), and monomer of polyphenol dominated by monomer with MWs 193.17 and 193.22 Da. and relative intensity 100 %. Fermented broccoli has potency as prebiotic, meanwhile fermented spinach has potency as anti oxidant.

The structure of spinach Photosystem I studied by electron microscopy

NARCIS (Netherlands)

Boekema, Egbert J.; Wynn, R. Max; Malkin, Richard

1990-01-01

The structure of three types of Photosystem I (PS I) complex isolated from spinach chloroplasts was studied by electron microscopy and computer image analysis. Molecular projections (top views and side views) of a native PS I complex (PSI-200), an antenna-depleted PS I complex (PSI-100) and the PS I

Some physical properties of spinach (Spinacia oleracea L.) seed

African Journals Online (AJOL)

PRECIOUS

2010-02-01

Feb 1, 2010 ... namely, rubber (0.341 to 0.470), wood (0.318 to 0.391), stainless steel (0.271 to 0.364) and galvanised ... The dry seeds of spinach cultivar, local variety were used for all the ... The true density defined as the ratio between the mass of ... air velocity near the location of the seed suspension was measured.

Selection of Leafy Green Vegetable Varieties for a Pick-and-Eat Diet Supplement on ISS

Science.gov (United States)

Massa, Gioia D.; Wheeler, Raymond M.; Stutte, Gary W.; Richards, Jeffrey T.; Spencer, LaShelle E.; Hummerick, Mary E.; Douglas, Grace L.; Sirmons, Takiyah

2015-01-01

Several varieties of leafy vegetables were evaluated with the goal of selecting those with the best growth, nutrition, and organoleptic acceptability for ISS. Candidate species were narrowed to commercially available cultivars with desirable growth attributes for space (e.g., short stature and rapid growth). Seeds were germinated in controlled environment chambers under conditions similar to what might be found in the Veggie plant growth chamber on ISS. Eight varieties of leafy greens were grown: 'Tyee' spinach, 'Flamingo' spinach, 'Outredgeous' Red Romaine lettuce, 'Waldmann's Dark Green' leaf lettuce, 'Bull's Blood' beet, 'Rhubarb' Swiss chard, 'Tokyo Bekana' Chinese cabbage, and Mizuna. Plants were harvested at maturity and biometric data on plant height, diameter, chlorophyll content, and fresh mass were obtained. Tissue was ground and extractions were performed to determine the tissue elemental content of Potassium (K), Magnesium (Mg), Calcium (Ca) and Iron (Fe). Following the biometric/elemental evaluation, four of the eight varieties were tested further for levels of anthocyanins, antioxidant (ORAC-fluorescein) capacity, lutein, zeaxanthin, and Vitamin K. For sensory evaluation, 'Outredgeous' lettuce, Swiss chard, Chinese cabbage, and Mizuna plants were grown, harvested when mature, packaged under refrigerated conditions, and sent to the JSC Space Food Systems Laboratory. Tasters evaluated overall acceptability, appearance, color intensity, bitterness, flavor, texture, crispness and tenderness. All varieties received acceptable scores with overall ratings greater than 6 on a 9-point hedonic scale. Chinese cabbage was the highest rated, followed by Mizuna, 'Outredgeous' lettuce, and Swiss chard. Based on our results, the selected varieties of Chinese cabbage, lettuce, Swiss chard and Mizuna seem suitable for a pick-and-eat scenario on ISS with a ranking based on all factors analyzed to help establish priority.

PLANT PROTECTION PRODUCT RESIDUES IN AGRICULTURAL PRODUCTS OF SLOVENE ORIGIN FOUND IN 2008

Directory of Open Access Journals (Sweden)

Helena BAŠA ČESNIK

2012-01-01

Full Text Available In the year 2008, 166 apple, bean, carrot, cucumber, lettuce, pear, potato and spinach samples from Slovene producers were analysed for plant protection product residues. The samples were analysed for the presence of 158 different active compounds using three analytical methods. In two samples (1.2% exceeded maximum residue levels (MRLs were determined which is better than the results of the monitoring of pesticide residues in the products of plant origin in the 27 European Union, Member States (EU MS and 2 European Free Trade Association (EFTA States: Norway and Iceland in 2008 (2.2%. The most frequently found active substance in agricultural products was dithiocarbamates. Products which contained 4 or more active substances per sample were apples and pears.

Modeling Nitrogen Decrease in Water Lettuce Ponds from Waste Stabilization Ponds

Science.gov (United States)

Putri, Gitta Agnes; Sunarsih

2018-02-01

This paper presents about the dynamic modeling of the Water Lettuce ponds as a form of improvement from the Water Hyacinth ponds. The purpose of this paper is to predict nitrogen decrease and nitrogen transformation in Water Lettuce ponds integrated with Waste Stabilization Ponds. The model consists of 4 mass balances, namely Dissolved Organic Nitrogen (DON), Particulate Organic Nitrogen (PON), ammonium (NH4+), Nitrate and Nitrite (NOx). The process of nitrogen transformation which considered in a Water Lettuce ponds, namely hydrolysis, mineralization, nitrification, denitrification, plant and bacterial uptake processes. Numerical simulations are performed by giving the values of parameters and the initial values of nitrogen compounds based on a review of previous studies. Numerical results show that the rate of change in the concentration of nitrogen compounds in the integration ponds of waste stabilization and water lettuce decreases and reaches stable at different times.

Evaluation of viability PCR performance for assessing norovirus infectivity in fresh-cut vegetables and irrigation water.

Science.gov (United States)

Randazzo, W; López-Gálvez, Francisco; Allende, A; Aznar, R; Sánchez, G

2016-07-16

Norovirus (NoV) detection in food and water is mainly carried out by quantitative RT-PCR (RT-qPCR). The inability to differentiate between infectious and inactivated viruses and the resulting overestimation of viral targets is considered a major disadvantage of RT-qPCR. Initially, conventional photoactivatable dyes (i.e. propidium monoazide, PMA and ethidium monoazide, EMA) and newly developed ones (i.e. PMAxx and PEMAX) were evaluated for the discrimination between infectious and thermally inactivated NoV genogroup I (GI) and II (GII) suspensions. Results showed that PMAxx was the best photoactivatable dye to assess NoV infectivity. This procedure was further optimized in artificially inoculated lettuce. Pretreatment with 50μM PMAxx and 0.5% Triton X-100 (Triton) for 10min reduced the signal of thermally inactivated NoV by ca. 1.8 logs for both genogroups in lettuce concentrates. Additionally, this pretreatment reduced the signal of thermally inactivated NoV GI between 1.4 and 1.9 logs in spinach and romaine and lamb's lettuces and by >2 logs for NoV GII in romaine and lamb's lettuce samples. Moreover this pretreatment was satisfactorily applied to naturally-contaminated water samples with NoV GI and GII. Based on the obtained results this pretreatment has the potential to be integrated in routine diagnoses to improve the interpretation of positive NoV results obtained by RT-qPCR. Copyright © 2016 Elsevier B.V. All rights reserved.

LC-MS Untargeted Metabolomics To Explain the Signal Metabolites Inducing Browning in Fresh-Cut Lettuce.

Science.gov (United States)

García, Carlos J; García-Villalba, Rocío; Gil, María I; Tomas-Barberan, Francisco A

2017-06-07

Enzymatic browning is one of the main causes of quality loss in lettuce as a prepared and ready-to-eat cut salad. An untargeted metabolomics approach using UPLC-ESI-QTOF-MS was performed to explain the wound response of lettuce after cutting and to identify the metabolites responsible of browning. Two cultivars of Romaine lettuce with different browning susceptibilities were studied at short time intervals after cutting. From the total 5975 entities obtained from the raw data after alignment, filtration reduced the number of features to 2959, and the statistical analysis found that only 1132 entities were significantly different. Principal component analysis (PCA) clearly showed that these samples grouped according to cultivar and time after cutting. From those, only 15 metabolites belonging to lysophospholipids, oxylipin/jasmonate metabolites, and phenolic compounds were able to explain the browning process. These selected metabolites showed different trends after cutting; some decreased rapidly, others increased but decreased thereafter, whereas others increased during the whole period of storage. In general, the fast-browning cultivar showed a faster wound response and a higher raw intensity of some key metabolites than the slow-browning one. Just after cutting, the fast-browning cultivar contained 11 of the 15 browning-associated metabolites, whereas the slow-browning cultivar only had 5 of them. These metabolites could be used as biomarkers in breeding programs for the selection of lettuce cultivars with lower browning potential for fresh-cut applications.

Low-cost multispectral imaging for remote sensing of lettuce health

Science.gov (United States)

Ren, David D. W.; Tripathi, Siddhant; Li, Larry K. B.

2017-01-01

In agricultural remote sensing, unmanned aerial vehicle (UAV) platforms offer many advantages over conventional satellite and full-scale airborne platforms. One of the most important advantages is their ability to capture high spatial resolution images (1-10 cm) on-demand and at different viewing angles. However, UAV platforms typically rely on the use of multiple cameras, which can be costly and difficult to operate. We present the development of a simple low-cost imaging system for remote sensing of crop health and demonstrate it on lettuce (Lactuca sativa) grown in Hong Kong. To identify the optimal vegetation index, we recorded images of both healthy and unhealthy lettuce, and used them as input in an expectation maximization cluster analysis with a Gaussian mixture model. Results from unsupervised and supervised clustering show that, among four widely used vegetation indices, the blue wide-dynamic range vegetation index is the most accurate. This study shows that it is readily possible to design and build a remote sensing system capable of determining the health status of lettuce at a reasonably low cost (lettuce growers.

CaMV-35S promoter sequence-specific DNA methylation in lettuce.

Science.gov (United States)

Okumura, Azusa; Shimada, Asahi; Yamasaki, Satoshi; Horino, Takuya; Iwata, Yuji; Koizumi, Nozomu; Nishihara, Masahiro; Mishiba, Kei-ichiro

2016-01-01

We found 35S promoter sequence-specific DNA methylation in lettuce. Additionally, transgenic lettuce plants having a modified 35S promoter lost methylation, suggesting the modified sequence is subjected to the methylation machinery. We previously reported that cauliflower mosaic virus 35S promoter-specific DNA methylation in transgenic gentian (Gentiana triflora × G. scabra) plants occurs irrespective of the copy number and the genomic location of T-DNA, and causes strong gene silencing. To confirm whether 35S-specific methylation can occur in other plant species, transgenic lettuce (Lactuca sativa L.) plants with a single copy of the 35S promoter-driven sGFP gene were produced and analyzed. Among 10 lines of transgenic plants, 3, 4, and 3 lines showed strong, weak, and no expression of sGFP mRNA, respectively. Bisulfite genomic sequencing of the 35S promoter region showed hypermethylation at CpG and CpWpG (where W is A or T) sites in 9 of 10 lines. Gentian-type de novo methylation pattern, consisting of methylated cytosines at CpHpH (where H is A, C, or T) sites, was also observed in the transgenic lettuce lines, suggesting that lettuce and gentian share similar methylation machinery. Four of five transgenic lettuce lines having a single copy of a modified 35S promoter, which was modified in the proposed core target of de novo methylation in gentian, exhibited 35S hypomethylation, indicating that the modified sequence may be the target of the 35S-specific methylation machinery.

Phyllosphere Microbiota Composition and Microbial Community Transplantation on Lettuce Plants Grown Indoors

Science.gov (United States)

Williams, Thomas R.

2014-01-01

ABSTRACT The aerial surfaces of plants, or phyllosphere, are microbial habitats important to plant and human health. In order to accurately investigate microbial interactions in the phyllosphere under laboratory conditions, the composition of the phyllosphere microbiota should be representative of the diversity of microorganisms residing on plants in nature. We found that Romaine lettuce grown in the laboratory contained 10- to 100-fold lower numbers of bacteria than age-matched, field-grown lettuce. The bacterial diversity on laboratory-grown plants was also significantly lower and contained relatively higher proportions of Betaproteobacteria as opposed to the Gammaproteobacteria-enriched communities on field lettuce. Incubation of field-grown Romaine lettuce plants in environmental growth chambers for 2 weeks resulted in bacterial cell densities and taxa similar to those on plants in the field but with less diverse bacterial populations overall. In comparison, the inoculation of laboratory-grown Romaine lettuce plants with either freshly collected or cryopreserved microorganisms recovered from field lettuce resulted in the development of a field-like microbiota on the lettuce within 2 days of application. The survival of an inoculated strain of Escherichia coli O157:H7 was unchanged by microbial community transfer; however, the inoculation of E. coli O157:H7 onto those plants resulted in significant shifts in the abundance of certain taxa. This finding was strictly dependent on the presence of a field-associated as opposed to a laboratory-associated microbiota on the plants. Phyllosphere microbiota transplantation in the laboratory will be useful for elucidating microbial interactions on plants that are important to agriculture and microbial food safety. PMID:25118240

Stability of carotenoids and tocopherols in ready-to-eat baby-leaf lettuce and salad rocket during low-temperature storage.

Science.gov (United States)

Saini, Ramesh Kumar; Shang, Xiao Min; Ko, Eun Young; Choi, Jeong Hee; Keum, Young-Soo

2015-08-01

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 better visual quality up to eight days of storage at both the temperatures. In most cases, the quality was correlated with the chlorophyll contents. The highest significant (p tocopherols were observed in samples stored at 4 °C. Also, carotenoids and tocopherols are maximum stable in green and red romaine lettuce, respectively.

Varietal response to lead by lettuce

Energy Technology Data Exchange (ETDEWEB)

John, M.K.

1977-06-01

Nine lettuce varieties were hydroponically grown at six substrate Pb concentrations to 50 ppM in substrate. Top and root tissue Pb concentration, amounts assimilated, and translocation to edible tissue were dependent on the variety as well as substrate lead and exposure duration. Even though Pb in substrate was in a precipitated form, lettuce plants could assimilate and translocate Pb. Differential response of varieties with similar morphology indicated genetical regulated physiological mechanisms of Pb assimilation and translocation. This evidence suggests varietal selection could minimize human and animal dietary intake of Pb via food plants. While early growth of some varieties was stimulated by low concentrations of Pb, and high solution concentrations suppressed growth of several varieties, genetic variation also included non-significant response of growth.

Exploring the Limits of Crop Productivity: High Light Studies with Lettuce

OpenAIRE

USU Crop Physiology Lab

2015-01-01

There are many different leaf lettuce cultivars and they range in color from light green and yellow to deep green as a result of higher concentrations of chlorophyll in the leaves. We tested four cultivars in high light to explore the limits of lettuce productivity.

Assessing the growth of Escherichia coli O157:H7 and Salmonella in spinach, lettuce, parsley and chard extracts at different storage temperatures.

Science.gov (United States)

Posada-Izquierdo, G; Del Rosal, S; Valero, A; Zurera, G; Sant'Ana, A S; Alvarenga, V O; Pérez-Rodríguez, F

2016-06-01

The objective of this work was to study the growth potential of Escherichia coli O157:H7 and Salmonella spp. in leafy vegetable extracts at different temperature conditions. Cocktails of five strains of E. coli O157:H7 and of Salmonella enterica were used. Inoculated aqueous vegetable extracts were incubated at 8, 10, 16 and 20°C during 21 days. Microbial growth was monitored using Bioscreen C(®) . In spinach extract, results showed that for E. coli O157:H7 and Salmonella significant differences (P parsley showed the lowest values of μabs , below 0·008 h(-1) . The coefficients of variance (CoV) calculated for the different replicates evidenced that at low temperature (8°C) a more variable behaviour of both pathogens is expected (CoV > 180%). This study provides evidence that aqueous extracts from vegetable tissues can result in distinct growth niche producing different response in various types of vegetables. Finally, these results can be used as basis to establish risk rankings of pathogens and leafy vegetable matrices with relation to their potential growth. © 2016 The Society for Applied Microbiology.

Effectiveness of Active Packaging on Control of Escherichia Coli O157:H7 and Total Aerobic Bacteria on Iceberg Lettuce.

Science.gov (United States)

Lu, Haixia; Zhu, Junli; Li, Jianrong; Chen, Jinru

2015-06-01

Contaminated leafy green vegetables have been linked to several outbreaks of human gastrointestinal infections. Antimicrobial interventions that are adoptable by the fresh produce industry for control of pathogen contamination are in great demand. This study was undertaken to evaluate the efficacy of sustained active packaging on control of Escherichia coli O157:H7 and total aerobic bacteria on lettuce. Commercial Iceberg lettuce was inoculated with a 3-strain mixture of E. coli O157:H7 at 10(2) or 10(4) CFU/g. The contaminated lettuce and un-inoculated controls were placed respectively in 5 different active packaging structures. Traditional, nonactive packaging structure was included as controls. Packaged lettuce was stored at 4, 10, or 22 °C for 3 wk and sampled weekly for the population of E. coli O157:H7 and total aerobic bacteria. Results showed that packaging structures with ClO2 generator, CO2 generator, or one of the O2 scavengers effectively controlled the growth of E. coli O157:H7 and total aerobic bacteria under all storage conditions. Packaging structure with the ClO2 generator was most effective and no E. coli O157:H7 was detected in samples packaged in this structure except for those that were inoculated with 4 log CFU/g of E. coli O157:H7 and stored at 22 °C. Packaging structures with an oxygen scavenger and the allyl isothiocyanate generator were mostly ineffective in control of the growth of the bacteria on Iceberg lettuce. The research suggests that some of the packaging structures evaluated in the study can be used to control the presence of foodborne pathogens on leafy green vegetables. © 2015 Institute of Food Technologists®

Author Details

African Journals Online (AJOL)

Abstract PDF · Vol 17 (2012) - Articles Determination of some heavy metals in spinach and lettuce from selected markets in Kaduna metropolis. Abstract PDF · Vol 17 (2012) - Articles Determination of Heavy Metals in Leaves of Mangifera Indica, Psidium Guajava L. and Anacardium Occidentale L. in Trikania Industrial Area, ...

Phenolic profile evolution of different ready-to-eat baby-leaf vegetables during storage.

Science.gov (United States)

Santos, J; Oliveira, M B P P; Ibáñez, E; Herrero, M

2014-01-31

Ready-to-eat baby-leaf vegetables market has been growing and offering to consumers convenient, healthy and appealing products, which may contain interesting bioactive compounds. In this work, the composition and the evolution of the phenolic compounds from different baby-leaf vegetables during refrigerated storage was studied. The phenolic compounds were extracted using pressurized liquid extraction (PLE) and the phenolic profile of each sample was analyzed and quantified by using LC-MS and LC-DAD methods, respectively, at the beginning and at the end of a 10-day storage period. The baby-leaf vegetables studied included green lettuce, ruby red lettuce, swiss chard, spinach, pea shoots, watercress, garden cress, mizuna, red mustard, wild rocket and spearmint samples and a total of 203 phenolic compounds were tentatively identified and quantified. The main naturally phenolic compounds identified correspond to glycosylated flavonoids, with exception of green lettuce and spearmint leaves which had a higher content of hydroxycinnamic acids. Quantification of the main compounds showed a 10-fold higher content of total phenolic content of ruby red lettuce (483mgg(-1)) in relation to the other samples, being the lowest values found in the garden cress (12.8mgg(-1)) and wild rocket leaves (8.1mgg(-1)). The total phenolic content only showed a significant change (plettuce (+17.5%), mizuna (+7.8%), red mustard (-23.7%) and spearmint (-13.8%) leaves. Within the different classes of phenolic compounds monitored, the flavonols showed more stable contents than the hydroxycinnamic and hydroxybenzoic acids, although the behavior of each compound varied strongly among samples. Copyright © 2014. Published by Elsevier B.V.

Influence of cold stress on contents of soluble sugars, vitamin C and free amino acids including gamma-aminobutyric acid (GABA) in spinach (Spinacia oleracea).

Science.gov (United States)

Yoon, Young-Eun; Kuppusamy, Saranya; Cho, Kye Man; Kim, Pil Joo; Kwack, Yong-Bum; Lee, Yong Bok

2017-01-15

The contents of soluble sugars (sucrose, fructose, glucose, maltose and raffinose), vitamin C and free amino acids (34 compounds, essential and non-essential) were quantified in open-field and greenhouse-grown spinaches in response to cold stress using liquid chromatography. In general, greenhouse cultivation produced nutritionally high value spinach in a shorter growing period, where the soluble sugars, vitamin C and total amino acids concentrations, including essential were in larger amounts compared to those grown in open-field scenarios. Further, low temperature exposure of spinach during a shorter growth period resulted in the production of spinach with high sucrose, ascorbate, proline, gamma-aminobutyric acid, valine and leucine content, and these constitute the most important energy/nutrient sources. In conclusion, cultivation of spinach in greenhouse at a low temperature (4-7°C) and exposure for a shorter period (7-21days) before harvest is recommended. This strategy will produce a high quality product that people can eat. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative transfer of Escherichia coli O157:H7 to equipment during small-scale production of fresh-cut leafy greens.

Science.gov (United States)

Buchholz, Annemarie L; Davidson, Gordon R; Marks, Bradley P; Todd, Ewen C D; Ryser, Elliot T

2012-07-01

Postharvest contamination and subsequent spread of Escherichia coli O157:H7 can occur during shredding, conveying, fluming, and dewatering of fresh-cut leafy greens. This study quantified E. coli O157:H7 transfer from leafy greens to equipment surfaces during simulated small-scale commercial processing. Three to five batches (22.7 kg) of baby spinach, iceberg lettuce, and romaine lettuce were dip inoculated with a four-strain cocktail of avirulent, green fluorescent protein-labeled, ampicillinresistant E. coli O157:H7 to contain ∼10(6), 10(4), and 10(2) CFU/g, and then were processed after 1 h of draining at ∼23°C or 24 h of storage at 4°C. Lettuce was shredded using an Urschel TransSlicer at two different blade and belt speeds to obtain normal (5 by 5 cm) and more finely shredded (0.5 by 5 cm) lettuce. Thereafter, the lettuce was step conveyed to a flume tank and was washed and then dried using a shaker table and centrifugal dryer. Product (25-g) and water (40-ml) samples were collected at various points during processing. After processing, product contact surfaces (100 cm(2)) on the shredder (n = 14), conveyer (n = 8), flume tank (n = 11), shaker table (n = 9), and centrifugal dryer (n = 8) were sampled using one-ply composite tissues. Sample homogenates diluted in phosphate or neutralizing buffer were plated, with or without prior 0.45- m m membrane filtration, on Trypticase soy agar containing 0.6% yeast extract supplemented with 100 ppm of ampicillin to quantify green fluorescent protein-labeled E. coli O157:H7 under UV light. During leafy green processing, ∼90% of the E. coli O157:H7 inoculum transferred to the wash water. After processing, E. coli O157:H7 populations were highest on the conveyor and shredder (Ptransfer.

Suficiência amostral para alface cultivada em diferentes ambientes Sample sufficiency for lettuce grown in different environments

Directory of Open Access Journals (Sweden)

Daniel Santos

2010-04-01

Full Text Available Com o objetivo de estimar o tamanho de amostra para alface cultivada em diferentes ambientes, foram conduzidos quatro cultivos com alface, dois deles foram realizados no ano de 2007, com a cultivar 'Vera', e dois foram realizados no ano de 2008, com a cultivar 'Amanda'. Os ambientes em 2007 foram estufa e a campo, e em 2008 foram estufa e túnel. Em ambos os anos de cultivo, foram avaliadas a fitomassa fresca e fitomassa seca. Para cada variável, em cada linha de cultivo, foram estimadas a média, a variância e o coeficiente de variação. Para testar a homogeneidade das variâncias entre as linhas, aplicou-se o teste de Bartlett, a 5% de significância. Nos casos em que as variâncias das linhas foram homogêneas, calculou-se um CV% médio para cada ambiente e este foi utilizado para o cálculo do tamanho de amostra. Nos casos em que as variâncias foram heterogêneas, utilizou-se o maior CV% do ambiente para o cálculo do tamanho da amostra. Os resultados mostraram que, em 40% dos experimentos, quando a variável foi a fitomassa fresca, e em 60%, quando foi a seca, os diferentes ambientes de produção proporcionaram variabilidades significativamente diferentes entre as linhas de cultivo. Foi possível determinar que, com a semiamplitude do intervalo de confiança de 10%, devem ser amostradas 30, 40 e 33 plantas na linha de cultivo, na estufa, no túnel e a campo respectivamente, para a fitomassa fresca das plantas. Já para a fitomassa seca das plantas devem ser amostradas 27, 29 e 32 plantas, respectivamente, para estufa, túnel e campo.The aim of this study was to estimate the sample size for lettuce cultivated in different environments, and for this four lettuce crops were cultivated. Two of them were conducted in 2007, with the cultivar Vera and two in 2008 with the cultivar 'Amanda'. The environments in 2007 were greenhouse and field and in 2008, greenhouse and tunnel. In both years of cultivation the fresh biomass and dry weight were

Non-destructive prediction of pigment content in lettuce based on visible-NIR spectroscopy.

Science.gov (United States)

Steidle Neto, Antonio José; Moura, Lorena de Oliveira; Lopes, Daniela de Carvalho; Carlos, Lanamar de Almeida; Martins, Luma Moreira; Ferraz, Leila de Castro Louback

2017-05-01

Lettuce (Lactuca sativa L.) is one of the most important salad vegetables in the world, with a number of head shapes, leaf types and colors. The lettuce pigments play important physiological functions, such as photosynthetic processes and light stress defense, but they also benefit human health because of their antioxidant action and anticarcinogenic properties. In this study three lettuce cultivars were grown under different farming systems, and partial least squares models were built to predict the leaf chlorophyll, carotenoid and anthocyanin content. The three proposed models resulted in high coefficients of determination and variable importance for the projection values, as well as low estimative errors for calibration and external validation datasets. These results confirmed that it is possible to accurately predict chlorophyll, carotenoid and anthocyanin content of green and red lettuces, grown in different farming systems, based on the spectral reflectance from 500 to 1000 nm. The proposed models were adequate for estimating lettuce pigments in a quick and non-destructive way, representing an alternative to conventional measurement methods. Prediction accuracies were improved by using the detrending, smoothing and first derivative pretreatments to the original spectral signatures prior to estimating lettuce chlorophyll, carotenoid and anthocyanin content, respectively. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

On-line fresh-cut lettuce quality measurement system using hyperspectral imaging

Science.gov (United States)

Lettuce, which is a main type of fresh-cut vegetable, has been used in various fresh-cut products. In this study, an online quality measurement system for detecting foreign substances on the fresh-cut lettuce was developed using hyperspectral reflectance imaging. The online detection system with a s...

Lytic bacteriophages reduce Escherichia coli O157: H7 on fresh cut lettuce introduced through cross-contamination.

Science.gov (United States)

Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

2013-01-01

The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield™) or a control (phosphate buffered saline, PBS) was applied to lettuce by either; (1) immersion of lettuce in 500 ml of EcoShield™ 8.3 log PFU/ml or 9.8 log PFU/ml for up to 2 min before inoculation with E. coli O157:H7; (2) spray-application of EcoShield™ (9.3 log PFU/ml) to lettuce after inoculation with E. coli O157:H7 (4.10 CFU/cm 2 ) following exposure to 50 μg/ml chlorine for 30 sec. After immersion studies, lettuce was spot-inoculated with E. coli O157:H7 (2.38 CFU/cm 2 ). Phage-treated, inoculated lettuce pieces were stored at 4°C for and analyzed for E. coli O157:H7 populations for up to 7 d. Immersion of lettuce in 9.8 log PFU/ml EcoShield™ for 2 min significantly (p PFU/ml) resulted in the deposition of high concentrations (7.8 log log PFU/cm 2 ) of bacteriophages on the surface of fresh cut lettuce, potentially contributing to the efficacy of the lytic phages on lettuce. Spraying phages on to inoculated fresh cut lettuce after being washed in hypochlorite solution was significantly more effective in reducing E. coli O157:H7 populations (2.22 log CFU/cm 2 ) on day 0 compared with control treatments (4.10 log CFU/cm 2 ). Both immersion and spray treatments provided protection from E. coli O157:H7 contamination on lettuce, but spray application of lytic bacteriophages to lettuce was more effective in immediately reducing E. coli O157:H7 populations fresh cut lettuce.

Growth and photosynthesis of lettuce

NARCIS (Netherlands)

Holsteijn, van H.M.C.

1981-01-01

Butterhead lettuce is an important glass-house crop in the poor light period in The Netherlands. Fundamental data about the influence of temperature, light and CO ₂ on growth and photosynthesis are important e.g. to facilitate selection criteria for new cultivars. In

Selenium accumulation in lettuce germplasm

Science.gov (United States)

Selenium (Se) is an essential micronutrient for animals and humans. Increasing Se content in food crops offers an effective approach to reduce the widespread selenium deficiency problem in many parts of the world. In this study, we evaluated thirty diverse accessions of lettuce (Lactuca sativa L.) f...

Screening of lettuce germplasm for agronomic traits under low water conditions

Science.gov (United States)

After a preliminary screening of over 3,500 varieties, we selected 200 cultivars of butterhead, cos, crisphead, leaf, and stem lettuce (Lactuca sativa L.) and wild prickly lettuce (Lactuca serriola L.) to test under high water (150% ET) and low water (50% ET) conditions in the field, and tracked com...

Impact of phytopathogen infection and extreme weather stress on internalization of Salmonella Typhimurium in lettuce.

Science.gov (United States)

Ge, Chongtao; Lee, Cheonghoon; Nangle, Ed; Li, Jianrong; Gardner, David; Kleinhenz, Matthew; Lee, Jiyoung

2014-01-03

Internalization of human pathogens, common in many types of fresh produce, is a threat to human health since the internalized pathogens cannot be fully inactivated/removed by washing with water or sanitizers. Given that pathogen internalization can be affected by many environmental factors, this study was conducted to investigate the influence of two types of plant stress on the internalization of Salmonella Typhimurium in iceberg lettuce during pre-harvest. The stresses were: abiotic (water stress induced by extreme weather events) and biotic (phytopathogen infection by lettuce mosaic virus [LMV]). Lettuce with and without LMV infection were purposefully contaminated with green fluorescence protein-labeled S. Typhimurium on the leaf surfaces. Lettuce was also subjected to water stress conditions (drought and storm) which were simulated by irrigating with different amounts of water. The internalized S. Typhimurium in the different parts of the lettuce were quantified by plate count and real-time quantitative PCR and confirmed with a laser scanning confocal microscope. Salmonella internalization occurred under the conditions outlined above; however internalization levels were not significantly affected by water stress alone. In contrast, the extent of culturable S. Typhimurium internalized in the leafy part of the lettuce decreased when infected with LMV under water stress conditions and contaminated with high levels of S. Typhimurium. On the other hand, LMV-infected lettuce showed a significant increase in the levels of culturable bacteria in the roots. In conclusion, internalization was observed under all experimental conditions when the lettuce surface was contaminated with S. Typhimurium. However, the extent of internalization was only affected by water stress when lettuce was infected with LMV. © 2013.

Analysis of eleven phenolic compounds including novel p-coumaroyl derivatives in lettuce (Lactuca sativa L.) by ultra-high-performance liquid chromatography with photodiode array and mass spectrometry detection.

Science.gov (United States)

Ribas-Agustí, Albert; Gratacós-Cubarsí, Marta; Sárraga, Carmen; García-Regueiro, José-Antonio; Castellari, Massimo

2011-01-01

Lettuce is a widely consumed vegetable and a good source of phenolic compounds. Several factors (genetic, agronomical and environmental) can influence the lettuce composition; their effects are not completely defined and more studies are needed on this topic. To develop an improved ultra-high-performance liquid chromatography (UHPLC) method to quantify the main target intact phenolic compounds in lettuce. UHPLC identification of the compounds was supported by PAD spectra and MS(n) analyses. Quantification was carried out by PAD, by creating matrix-matched calibration curves at the specific wavelength for each compound. Sample pretreatment was simplified, with neither purification nor hydrolysis steps. Chromatographic conditions were chosen to minimise matrix interferences and to give a suitable separation of the major phenolic compounds within 27 min. The method allowed the quantification of 11 intact phenolic compounds in Romaine lettuces, including phenolic acids (caffeoyl and p-coumaroyl esters) and flavonoids (quercetin glycosides). Four p-coumaroyl esters were tentatively identified and quantified for the first time in lettuce. The main intact phenolic compounds, including four novel p-coumaroyl esters, were simultaneously quantified in lettuce with optimal performances and a reduced total time of analysis. These findings make headway in the understanding of the lettuce phytochemicals with potential nutritional relevance. Copyright © 2011 John Wiley & Sons, Ltd.

Flavonoid-rich apples and nitrate-rich spinach augment nitric oxide status and improve endothelial function in healthy men and women: a randomized controlled trial.

Science.gov (United States)

Bondonno, Catherine P; Yang, Xingbin; Croft, Kevin D; Considine, Michael J; Ward, Natalie C; Rich, Lisa; Puddey, Ian B; Swinny, Ewald; Mubarak, Aidilla; Hodgson, Jonathan M

2012-01-01

Flavonoids and nitrates in fruits and vegetables may protect against cardiovascular disease. Dietary flavonoids and nitrates can augment nitric oxide status via distinct pathways, which may improve endothelial function and lower blood pressure. Recent studies suggest that the combination of flavonoids and nitrates can enhance nitric oxide production in the stomach. Their combined effect in the circulation is unclear. Here, our objective was to investigate the independent and additive effects of flavonoid-rich apples and nitrate-rich spinach on nitric oxide status, endothelial function, and blood pressure. A randomized, controlled, crossover trial with healthy men and women (n=30) was conducted. The acute effects of four energy-matched treatments (control, apple, spinach, and apple+spinach), administered in random order, were compared. Measurements included plasma nitric oxide status, assessed by measuring S-nitrosothiols+other nitrosylated species (RXNO) and nitrite, blood pressure, and endothelial function, measured as flow-mediated dilatation of the brachial artery. Results are means and 95% CI. Relative to control, all treatments resulted in higher RXNO (control, 33 nmol/L, 26, 42; apple, 51 nmol/L, 40, 65; spinach, 86 nmol/L, 68, 110; apple+spinach, 69 nmol/L, 54, 88; Pflow-mediated dilatation (Peffect was observed on diastolic blood pressure. The combination of apple and spinach did not result in additive effects on nitric oxide status, endothelial function, or blood pressure. In conclusion, flavonoid-rich apples and nitrate-rich spinach can independently augment nitric oxide status, enhance endothelial function, and lower blood pressure acutely, outcomes that may benefit cardiovascular health. Copyright © 2011 Elsevier Inc. All rights reserved.

Insect molting hormone and sterol biosynthesis in spinach

International Nuclear Information System (INIS)

Grebenok, R.J.; Adler, J.H.

1990-01-01

Insect molting hormones, which are produced by plants and are effective molecules in the control of insect crop pests, are biosynthesized in developing spinach leaves (Spinacia oleracea L.). The major sterols biosynthesized by spinach are avenasterol (24α-ethyl-5α-cholesta-7,24(28)-dien-3β-ol), spinasterol (24α-ethyl-5α-cholesta-7,22-dien-3β-ol), and 22-dihydrospinasterol (24α-ethyl-5α-cholest-7-en-3β-ol). The major ecdysteroids biosynthesized are ecdysterone (2β,3β,14α,20R,22R,25-hexahydroxy-5β-cholest-7-en-6-one) and polypodine B (2β,3β,5β,14α,20R,22R,25-heptahycroxycholest-7-en-6-one) and polypodine B (2β,3β,5β,14α,20R,22R,25-heptahydroxycholest-7-en-6-one). When labeled 2- 14 C-mevalonic acid was incorporated into young leaves isolated squalene, sterols and ecdysteroids contained the label. During a short (16 h) incorporation period in intact young leaves of 100 day old plants, the avenasterol has the highest specific activity in counts per minute per μg of sterol followed by 22-dihydrospinasterol which is more highly labeled than spinasterol. The ecdysteroids synthesized, on an entire plant basis, account for 20% of the total steroid (sterol and ecdysteroid) isolated from the plant

IPM for fresh-market lettuce production in the desert southwest: the produce paradox.

Science.gov (United States)

Palumbo, John C; Castle, Steven J

2009-12-01

In the 'Integrated Control Concept', Stern et al. emphasized that, although insecticides are necessary for agricultural production, they should only be used as a last resort and as a complement to biological control. They argued that selective insecticide use should only be attempted after it has been determined that insect control with naturally occurring biotic agents is not capable of preventing economic damage. However, they concluded their seminal paper by emphasizing that integrated control will not work where natural enemies are inadequate or where economic thresholds are too low to rely on biological control. Thus, it is no surprise that insect control in high-value, fresh-market lettuce crops grown in the desert southwest have relied almost exclusively on insecticides to control a complex of mobile, polyphagous pests. Because lettuce and leafy greens are short-season annual crops with little or no tolerance for insect damage or contamination, biological control is generally considered unacceptable. High expectations from consumers for aesthetically appealing produce free of pesticide residues further forces vegetable growers to use chemical control tactics that are not only effective but safe. Consequently, scientists have been developing integrated pest management (IPM) programs for lettuce that are aimed at reducing the economic, occupational and dietary risks associated with chemical controls of the past. Most of these programs have drawn upon the integrated control concept and promote the importance of understanding the agroecosystem, and the need to sample for pest status and use action thresholds for cost-effective insect control. More recently, pest management programs have implemented newly developed, reduced-risk chemistries that are selectively efficacious against key pests. This paper discusses the influence that the integrated control concept, relative to zero-tolerance market standards and other constraints, has had on the adoption of pest

Biological Control of Lettuce Drop and Host Plant Colonization by Rhizospheric and Endophytic Streptomycetes

Science.gov (United States)

Chen, Xiaoyulong; Pizzatti, Cristina; Bonaldi, Maria; Saracchi, Marco; Erlacher, Armin; Kunova, Andrea; Berg, Gabriele; Cortesi, Paolo

2016-01-01

Lettuce drop, caused by the soil borne pathogen Sclerotinia sclerotiorum, is one of the most common and serious diseases of lettuce worldwide. Increased concerns about the side effects of chemical pesticides have resulted in greater interest in developing biocontrol strategies against S. sclerotiorum. However, relatively little is known about the mechanisms of Streptomyces spp. as biological control agents against S. sclerotiorum on lettuce. Two Streptomyces isolates, S. exfoliatus FT05W and S. cyaneus ZEA17I, inhibit mycelial growth of Sclerotinia sclerotiorum by more than 75% in vitro. We evaluated their biocontrol activity against S. sclerotiorum in vivo, and compared them to Streptomyces lydicus WYEC 108, isolated from Actinovate®. When Streptomyces spp. (106 CFU/mL) were applied to S. sclerotiorum inoculated substrate in a growth chamber 1 week prior lettuce sowing, they significantly reduced the risk of lettuce drop disease, compared to the inoculated control. Interestingly, under field conditions, S. exfoliatus FT05W and S. cyaneus ZEA17I protected lettuce from drop by 40 and 10% respectively, whereas S. lydicus WYEC 108 did not show any protection. We further labeled S. exfoliatus FT05W and S. cyaneus ZEA17I with the enhanced GFP (EGFP) marker to investigate their rhizosphere competence and ability to colonize lettuce roots using confocal laser scanning microscopy (CLSM). The abundant colonization of young lettuce seedlings by both strains demonstrated Streptomyces' capability to interact with the host from early stages of seed germination and root development. Moreover, the two strains were detected also on 2-week-old roots, indicating their potential of long-term interactions with lettuce. Additionally, scanning electron microscopy (SEM) observations showed EGFP-S. exfoliatus FT05W endophytic colonization of lettuce root cortex tissues. Finally, we determined its viability and persistence in the rhizosphere and endorhiza up to 3 weeks by quantifying its

Biological control of lettuce drop and host plant colonization by rhizospheric and endophytic streptomycetes

Directory of Open Access Journals (Sweden)

Xiaoyulong eChen

2016-05-01

Full Text Available Lettuce drop, caused by the soil borne pathogen Sclerotinia sclerotiorum, is one of the most common and serious diseases of lettuce worldwide. Increased concerns about the side effects of chemical pesticides have resulted in greater interest in developing biocontrol strategies against S. sclerotiorum. However, relatively little is known about the mechanisms of Streptomyces spp. as biological control agents against S. sclerotiorum on lettuce. Two Streptomyces isolates, S. exfoliatus FT05W and S. cyaneus ZEA17I, inhibit mycelial growth of Sclerotinia sclerotiorum by more than 75% in vitro. We evaluated their biocontrol activity against S. sclerotiorum in vivo, and compared them to Streptomyces lydicus WYEC 108, isolated from Actinovate®. When Streptomyces spp. (106 CFU/mL were applied to S. sclerotiorum inoculated substrate in a growth chamber one week prior lettuce sowing, they significantly reduced the risk of lettuce drop disease, compared to the inoculated control. Interestingly, under field conditions, S. exfoliatus FT05W and S. cyaneus ZEA17I protected lettuce from drop by 40% and 10% respectively, whereas S. lydicus WYEC 108 did not show any protection. We further labeled S. exfoliatus FT05W and S. cyaneus ZEA17I with the enhanced GFP (EGFP marker to investigate their rhizosphere competence and ability to colonize lettuce roots using confocal laser scanning microscopy (CLSM. The abundant colonization of young lettuce seedlings by both strains demonstrated Streptomyces’ capability to interact with the host from early stages of seed germination and root development. Moreover, the two strains were detected also on two-week-old roots, indicating their potential of long-term interactions with lettuce. Additionally, scanning electron microscopy (SEM observations showed EGFP-S. exfoliatus FT05W endophytic colonization of lettuce root cortex tissues. Finally, we determined its viability and persistence in the rhizosphere and endorhiza up to

Effects of long-term low atmospheric pressure on gas exchange and growth of lettuce

Science.gov (United States)

Tang, Yongkang; Guo, Shuangsheng; Dong, Wenping; Qin, Lifeng; Ai, Weidang; Lin, Shan

2010-09-01

The objectives of this research were to determine photosynthesis, evapotranspiration and growth of lettuce at long-term low atmospheric pressure. Lettuce ( Lactuca sativa L . cv. Youmaicai) plants were grown at 40 kPa total pressure (8.4 kPa p) or 101 kPa total pressure (20.9 kPa p) from seed to harvest for 35 days. Germination rate of lettuce seeds decreased by 7.6% at low pressure, although this was not significant. There was no significant difference in crop photosynthetic rate between hypobaria and ambient pressure during the 35-day study. The crop evapotranspiration rate was significantly lower at low pressure than that at ambient pressure from 20 to 30 days after planting (DAP), but it had no significant difference before 20 DAP or after 30 DAP. The growth cycle of lettuce plants at low pressure was delayed. At low pressure, lettuce leaves were curly at the seedling stage and this disappeared gradually as the plants grew. Ambient lettuce plants were yellow and had an epinastic growth at harvest. The shoot height, leaf number, leaf length and shoot/root ratio were lower at low pressure than those at ambient pressure, while leaf area and root growth increased. Total biomass of lettuce plants grown at two pressures had no significant difference. Ethylene production at low pressure decreased significantly by 38.8% compared with ambient pressure. There was no significant difference in microelements, nutritional phytochemicals and nitrate concentrations at the two treatments. This research shows that lettuce can be grown at long-term low pressure (40 kPa) without significant adverse effects on seed germination, gas exchange and plant growth. Furthermore, ethylene release was reduced in hypobaria.

Environmental health risk assessment of ambient lead levels in Lisbon, Portugal: A full chain study approach

DEFF Research Database (Denmark)

Casimiro, E.; Philippe Ciffroy, P.; Serpa, P.

2011-01-01

to calculate the Pb levels in the various body systems. Our results showed a low health risk from Pb exposures. It also identified that ingestion of leafy vegetables (i.e. lettuce, cabbage, and spinach) and fruits contribute the most to total Pb blood levels. This full chain assessment approach of the 2FUN...

Dynamics of nonpersistent aphid-borne viruses in lettuce crops covered with UV-absorbing nets.

Science.gov (United States)

Legarrea, S; Betancourt, M; Plaza, M; Fraile, A; García-Arenal, F; Fereres, A

2012-04-01

Aphid-transmitted viruses frequently cause severe epidemics in lettuce grown under Mediterranean climates. Spatio-temporal dynamics of aphid-transmitted viruses and its vector were studied on lettuce (Lactuca sativa L.) grown under tunnels covered by two types of nets: a commercial UV-absorbing net (Bionet) and a Standard net. A group of plants infected by Cucumber mosaic virus (CMV, family Bromoviridae, genus Cucumovirus) and Lettuce mosaic virus (LMV, family Potyviridae, genus Potyvirus) was transplanted in each plot. The same virus-infected source plants were artificially infested by the aphid Macrosiphum euphorbiae (Thomas). Secondary spread of insects was weekly monitored and plants were sampled for the detection of viruses every two weeks. In 2008, the infection rate of both CMV and LMV were lower under the Bionet than under the Standard cover, probably due to the lower population density and lower dispersal rate achieved by M. euphorbiae. However, during spring of 2009, significant differences in the rate of infection between the two covers were only found for LMV six weeks after transplant. The spatial distribution of the viruses analysed by SADIE methodology was "at random", and it was not associated to the spatial pattern of the vector. The results obtained are discussed analyzing the wide range of interactions that occurred among UV-radiation, host plant, viruses, insect vector and environmental conditions. Our results show that UV-absorbing nets can be recommended as a component of an integrated disease management program to reduce secondary spread of lettuce viruses, although not as a control measure on its own. Copyright © 2011 Elsevier B.V. All rights reserved.

Lettuce flavonoids screening and phenotyping by chlorophyll fluorescence excitation ratio.

Science.gov (United States)

Zivcak, Marek; Brückova, Klaudia; Sytar, Oksana; Brestic, Marian; Olsovska, Katarina; Allakhverdiev, Suleyman I

2017-06-01

Environmentally induced variation and the genotypic differences in flavonoid and phenolic content in lettuce can be reliably detected using the appropriate parameters derived from the records of rapid non-invasive fluorescence technique. The chlorophyll fluorescence excitation ratio method was designed as a rapid and non-invasive tool to estimate the content of UV-absorbing phenolic compounds in plants. Using this technique, we have assessed the dynamics of accumulation of flavonoids related to developmental changes and environmental effects. Moreover, we have tested appropriateness of the method to identify the genotypic differences and fluctuations in total phenolics and flavonoid content in lettuce. Six green and two red genotypes of lettuce (Lactuca sativa L.) grown in pots were exposed to two different environments for 50 days: direct sunlight (UV-exposed) and greenhouse conditions (low UV). The indices based on the measurements of chlorophyll fluorescence after red, green and UV excitation indicated increase of the content of UV-absorbing compounds and anthocyanins in the epidermis of lettuce leaves. In similar, the biochemical analyses performed at the end of the experiment confirmed significantly higher total phenolic and flavonoid content in lettuce plants exposed to direct sun compared to greenhouse conditions and in red compared to green genotypes. As the correlation between the standard fluorescence indices and the biochemical records was negatively influenced by the presence of red genotypes, we proposed the use of a new parameter named Modified Flavonoid Index (MFI) taking into an account both absorbance changes due to flavonol and anthocyanin content, for which the correlation with flavonoid and phenolic content was relatively good. Thus, our results confirmed that the fluorescence excitation ratio method is useful for identifying the major differences in phenolic and flavonoid content in lettuce plants and it can be used for high-throughput pre

Effect of pH Upper Control Limit on Nutrient Solution Component and Water Spinach Growth under Hydroponics

OpenAIRE

Xuzhang Xue; Yinkun Li; Feng Li; Fang Zhang; Wenzhong Guo

2015-01-01

In this study, experiment with four levels of nutrient solution pH control upper limit was conducted to explore the optimal nutrient solution pH management scheme under hydroponics by evaluating the nutrient solution characters i.e., pH, Electric Conductivity (EC), nitrate, soluble phosphorus (soluble-P), water spinach growth and quality. The results showed that the nutrient solution pH was 8.2 and unsuitable for water spinach growth under the treatment with no pH regulation during the experi...

Growth experiment in lettuce [Lactuca sativa] using laser light

International Nuclear Information System (INIS)

Mori, Y.; Takatsuji, M.

2001-01-01

Photosynthetic rate, relative growth rate and vitamin C contents were measured in lettuce cultivated under red and blue lasers and the results were compared with those cultivated under light emitting diodes (LED). It was found that lettuce grew fairly healthily under red laser diode (650 nm) and blue laser (442 nm) with R/B ratio 10. However, both photosynthetic rate and growth rate rather diminished compared with LED cases. As for vitamin C contents, the result was about the same as LED cases

PROTEOMIC PROFILE REVEALS THE DIVERSITY AND COMPLEXITY OF LEAF PROTEINS IN SPINACH (BETA VULGARIS VAR. ALL GREEN

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Sudip Ghosh

2016-06-01

Full Text Available Leaf is a source organ that serves dual function in photosynthesis and transpiration. As a primary interface between plant and ecosystem, it performs a range of biological processes from carbon assimilation and metabolite partitioning to plant productivity. Basic features of the leaf functionality are conserved in angiosperms exhibiting common and unique characteristics. Spinach has been the model crop for studying leaf function, primarily photosynthesis. It is a reservoir of several hundreds of primary and secondary biomolecules. To better understand the molecular basis for photochemical reaction and metabolic partitioning, we developed leaf proteome of Indian spinach (Beta vulgaris var. all green. LC-ESI-MS/MS analysis identified 639 proteins exhibiting discrete molecular features and functions, including photosynthesis, transpiration, gaseous exchange, transport, redox status, cell defense, and floral induction besides the presence of proteins with unknown function. This represents the first comprehensive foliage proteome of green leafy vegetable. Together, this work provides important insights into the molecular networks underlying spinach leaf biological processes.

The phytoavailability of cadmium to lettuce in long-term biosolids-amended soils

Energy Technology Data Exchange (ETDEWEB)

Brown, S.L.; Chaney, R.L. [Dept. of Agriculture, Beltsville, MD (United States); Angle, J.S. [Univ. of Maryland, College Park, MD (United States). Dept. of Agronomy; Ryan, J.A. [Environmental Protection Agency, Cincinnati, OH (United States). National Risk Management Research Lab.

1998-09-01

A field study was conducted to assess the phytoavailability of Cd in long-term biosolids-amended plots managed at high and low pH. The experiment, established 13 to 15 yr prior to the present cropping, on a Christiana fine sandy loam soil used a variety of biosolids. Two of the biosolids had total Cd concentrations of 13.4 and 210 mg kg{sup {minus}1}. A Cd salt treatment, with Cd added to soil at a rate equivalent to the Cd added by the higher Cd biosolids applied at 100 Mg ha{sup {minus}1}, was also included. The lettuce (Lactuca sativa var. longifolia) cultivar (Paris Island Cos) used in the initial study was also used in the current study. Lettuce Cd was compared between treatments, and in relation to the soil Cd/soil organic C (OC) ratio. There has been no significant increase in plant Cd since the initial cropping. With 16% of the biosolids added OC remaining, lettuce grown on the soil amended with the more contaminated biosolids was not different than that of the initial cropping. Further, significantly less Cd was taken up by lettuce grown on biosolids-amended soil than lettuce grown on soil amended with equivalent rates of Cd salt. The Cd concentration in lettuce grown in the low Cd biosolids treatment was not different from the control. These results indicate that the potential hazards associated with food chain transfer of biosolids-applied Cd are substantially lower than equivalent Cd salt treatments, and that the hazards do not increase over time.

Genetic dissection of nonhost resistance of wild lettuce, Lactuca saligna, to downy mildew

OpenAIRE

Zhang, N.

2008-01-01

Lettuce downy mildew is the most destructive disease in lettuce (Lactuca spp.) cultivation and is caused by Bremia lactucae. The successful cross between its host L. sativa and the nonhost, L. saligna, and offers a rare chance to study the genetics of the nonhost resistance. From a set of 29 Backcross Inbred Lines (BILs) representing in total 96% of the L. saligna genome, 15 introgressions were identified to contribute to this resistance at one to four tested lettuce developmental stages and ...

Flavonoids in baby spinach (Spinacia oleracea L.): Changes during plant growth and storage

DEFF Research Database (Denmark)

Bergquist, S. Å. M.; Gertsson, U. E.; Knuthsen, Pia

2005-01-01

were analyzed by reversed phase HPLC. Twelve flavonoid peaks were detected. The main flavonoid, making up on average 43% of the total flavonoid concentration, was identified as 5,3',4'-trihydroxy-3-methoxy-6:7-methylenedioxyflavone-4'-glucuronide. Four other flavonoids each contributed 7......The variation in flavonoid concentration and composition was investigated in baby spinach (Spinacia oleracea L.) cv. Emilia sown on three occasions, each harvested at three growth stages at 6-day intervals. After harvest, leaves were stored in polypropylene bags at 2 or 10 degrees C. Flavonoids......-12% of the total flavonoid content. Total flavonoid content was relatively stable during normal retail storage conditions, although some of the individual flavonoid compounds showed considerable variation. The youngest plants had the highest flavonoid concentration, indicating that by harvesting the baby spinach...

Evaluation of respiratory parameters in minimally processed lettuce grown under organic or conventional system

Directory of Open Access Journals (Sweden)

Júlio César Mello

2010-12-01

Full Text Available The increased preference for minimally processed vegetables has been attributed to the health benefits associated with fresh produce and the demand for ready-to-eat salads. In this paper, lettuce (Lactuca sativa L. was evaluated for the effects of different cropping systems on the respiratory properties. Lettuce was packaged in low density polyethylene bags and stored in a refrigerator at 4 ºC. The concentration of carbon dioxide and oxygen inside the package was monitored during the storage at zero, three, six, eight, ten and twelve days by gas chromatography. Dry matter variation was measured gravimetrically up to day fourteen of storage. Values of respiratory rate for conventional lettuce increased from day 1 to 3 and remained low, while respiratory rate of the organic lettuce increased three-fold up to day 8, stabilizing at a high level. Variation in dry matter during storage also resulted from differences between the two cultivation systems. The highest content of dry matter was achieved by organic lettuce.

Opposite Effects of the Spinach Food Matrix on Lutein Bioaccessibility and Intestinal Uptake Lead to Unchanged Bioavailability Compared to Pure Lutein.

Science.gov (United States)

Margier, Marielle; Buffière, Caroline; Goupy, Pascale; Remond, Didier; Halimi, Charlotte; Caris-Veyrat, Catherine; Borel, Patrick; Reboul, Emmanuelle

2018-06-01

Food matrix is generally believed to alter carotenoid bioavailability, but its effect on xanthophylls is usually limited. This study thus aims to decipher the digestion-absorption process of lutein in the presence or not of a food matrix. Lutein transfer to gastric-like lipid droplets or artificial mixed micelles was assessed when lutein was added to test meals either as a pure molecule ((all-E)-lutein) or in canned spinach ((Z) + (all-E)-lutein). The obtained mixed micelles were delivered to Caco-2 cells to evaluate lutein uptake. Finally postprandial plasma lutein responses were compared in minipigs after the two test meals. Lutein transfer to gastric-like lipid droplets and to mixed micelles was higher when lutein was added in spinach than when it was added as pure lutein (+614% and +147%, respectively, p < 0.05). Conversely, lutein uptake was less effective when micellar lutein was from a meal containing spinach than from a meal containing its pure form (-55%, p < 0.05). In minipigs, postprandial lutein response was delayed with spinach but not significantly different after the two test meals. Opposite effects at the micellarization and intestinal cell uptake steps explain the lack of effect of spinach matrix on lutein bioavailability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Persistence of Two Campylobacter jejuni Strains in Soil and on Spinach Plants

International Nuclear Information System (INIS)

Jaderlund, L.; Arthurson, V.; Sessitsch, A.

2011-01-01

There are indications that the more frequent use of untreated organic residues for fertilization results in increased risk of contamination with human pathogens. Here, we evaluate the ability of two different strains of Campylobacter jejuni to persist in manure and soil as well as spread to spinach plants. It was revealed that different strategies for inoculation of C. jejuni contribute to the persistence of the bacterium in soil, roots, and shoots. Upon inoculation of the bacteria into manure prior to soil application, the amount of C. jejuni subsequently recovered in soil was higher than that from treatments involving the addition of C. jejuni cells to the soil after plant emergence. Irrespective of the bacterial inoculation dose and strategy employed, the C. jejuni content in soil remained relatively constant, whereas the majority of C. jejuni cells applied to spinach leaves could be recovered during the whole evaluation period of 21 days.

Inflorescence Development and the Role of LsFT in Regulating Bolting in Lettuce (Lactuca sativa L.)

Science.gov (United States)

Chen, Zijing; Han, Yingyan; Ning, Kang; Ding, Yunyu; Zhao, Wensheng; Yan, Shuangshuang; Luo, Chen; Jiang, Xiaotang; Ge, Danfeng; Liu, Renyi; Wang, Qian; Zhang, Xiaolan

2018-01-01

Lettuce (Lactuca sativa L.) is one of the most important leafy vegetable that is consumed during its vegetative growth. The transition from vegetative to reproductive growth is induced by high temperature, which has significant economic effect on lettuce production. However, the progression of floral transition and the molecular regulation of bolting are largely unknown. Here we morphologically characterized the inflorescence development and functionally analyzed the FLOWERING LOCUS T (LsFT) gene during bolting regulation in lettuce. We described the eight developmental stages during floral transition process. The expression of LsFT was negatively correlated with bolting in different lettuce varieties, and was promoted by heat treatment. Overexpression of LsFT could recover the late-flowering phenotype of ft-2 mutant. Knockdown of LsFT by RNA interference dramatically delayed bolting in lettuce, and failed to respond to high temperature. Therefore, this study dissects the process of inflorescence development and characterizes the role of LsFT in bolting regulation in lettuce. PMID:29403510

Inflorescence Development and the Role of LsFT in Regulating Bolting in Lettuce (Lactuca sativa L.).

Science.gov (United States)

Chen, Zijing; Han, Yingyan; Ning, Kang; Ding, Yunyu; Zhao, Wensheng; Yan, Shuangshuang; Luo, Chen; Jiang, Xiaotang; Ge, Danfeng; Liu, Renyi; Wang, Qian; Zhang, Xiaolan

2017-01-01

Lettuce ( Lactuca sativa L.) is one of the most important leafy vegetable that is consumed during its vegetative growth. The transition from vegetative to reproductive growth is induced by high temperature, which has significant economic effect on lettuce production. However, the progression of floral transition and the molecular regulation of bolting are largely unknown. Here we morphologically characterized the inflorescence development and functionally analyzed the FLOWERING LOCUS T (LsFT) gene during bolting regulation in lettuce. We described the eight developmental stages during floral transition process. The expression of LsFT was negatively correlated with bolting in different lettuce varieties, and was promoted by heat treatment. Overexpression of LsFT could recover the late-flowering phenotype of ft-2 mutant. Knockdown of LsFT by RNA interference dramatically delayed bolting in lettuce, and failed to respond to high temperature. Therefore, this study dissects the process of inflorescence development and characterizes the role of LsFT in bolting regulation in lettuce.

Bacterial networks and co-occurrence relationships in the lettuce root microbiota.

Science.gov (United States)

Cardinale, Massimiliano; Grube, Martin; Erlacher, Armin; Quehenberger, Julian; Berg, Gabriele

2015-01-01

Lettuce is one of the most common raw foods worldwide, but occasionally also involved in pathogen outbreaks. To understand the correlative structure of the bacterial community as a network, we studied root microbiota of eight ancient and modern Lactuca sativa cultivars and the wild ancestor Lactuca serriola by pyrosequencing of 16S rRNA gene amplicon libraries. The lettuce microbiota was dominated by Proteobacteria and Bacteriodetes, as well as abundant Chloroflexi and Actinobacteria. Cultivar specificity comprised 12.5% of the species. Diversity indices were not different between lettuce cultivar groups but higher than in L. serriola, suggesting that domestication lead to bacterial diversification in lettuce root system. Spearman correlations between operational taxonomic units (OTUs) showed that co-occurrence prevailed over co-exclusion, and complementary fluorescence in situ hybridization-confocal laser scanning microscopy (FISH-CLSM) analyses revealed that this pattern results from both potential interactions and habitat sharing. Predominant taxa, such as Pseudomonas, Flavobacterium and Sphingomonadaceae rather suggested interactions, even though these are not necessarily part of significant modules in the co-occurrence networks. Without any need for complex interactions, single organisms are able to invade into this microbial network and to colonize lettuce plants, a fact that can influence the susceptibility to pathogens. The approach to combine co-occurrence analysis and FISH-CLSM allows reliably reconstructing and interpreting microbial interaction networks. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Ultralow oxygen treatment for postharvest control of Nasonovia ribisnigri (Homoptera: Aphididae) on iceberg lettuce.

Science.gov (United States)

Liu, Yong-Biao

2005-12-01

The aphid Nasonovia ribisnigri (Mosley) is a common pest of lettuce in the United States. It hinders export of U.S. lettuce to the overseas market such as Japan where it is a quarantined pest. Ultralow oxygen treatments were studied for control of the insect on iceberg lettuce. Small-scale ultralow oxygen treatments in plastic jars were conducted at 1, 5, and 10 degrees C for different durations to determine effective treatment against nymphs and alates of N. ribisnigri. At oxygen levels of 0.015-0.025%, N. ribisnigri can be controlled in 3 d at 1 degrees C, 2 d at 5 degrees C, and 1 d at 10 degrees C. Large-scale ultralow oxygen treatments were conducted in bulk container treatment chambers with commercial iceberg lettuce heads for 2 d at 6 degrees C with oxygen levels of 0.015 and 0.025% and for 3 d at 3 degrees C with oxygen level of 0.015%. All treatments achieved complete control of N. ribisnigri. No negative impact on lettuce quality was detected after 2 wk of posttreatment storage. Therefore, the selected treatments have potential to be commercially developed for postharvest control of N. ribisnigri on iceberg lettuce.

Classification of different kinds of pesticide residues on lettuce based on fluorescence spectra and WT-BCC-SVM algorithm

Science.gov (United States)

Zhou, Xin; Jun, Sun; Zhang, Bing; Jun, Wu

2017-07-01

In order to improve the reliability of the spectrum feature extracted by wavelet transform, a method combining wavelet transform (WT) with bacterial colony chemotaxis algorithm and support vector machine (BCC-SVM) algorithm (WT-BCC-SVM) was proposed in this paper. Besides, we aimed to identify different kinds of pesticide residues on lettuce leaves in a novel and rapid non-destructive way by using fluorescence spectra technology. The fluorescence spectral data of 150 lettuce leaf samples of five different kinds of pesticide residues on the surface of lettuce were obtained using Cary Eclipse fluorescence spectrometer. Standard normalized variable detrending (SNV detrending), Savitzky-Golay coupled with Standard normalized variable detrending (SG-SNV detrending) were used to preprocess the raw spectra, respectively. Bacterial colony chemotaxis combined with support vector machine (BCC-SVM) and support vector machine (SVM) classification models were established based on full spectra (FS) and wavelet transform characteristics (WTC), respectively. Moreover, WTC were selected by WT. The results showed that the accuracy of training set, calibration set and the prediction set of the best optimal classification model (SG-SNV detrending-WT-BCC-SVM) were 100%, 98% and 93.33%, respectively. In addition, the results indicated that it was feasible to use WT-BCC-SVM to establish diagnostic model of different kinds of pesticide residues on lettuce leaves.

Phosphorus rates on yield and quality of lettuce seeds

OpenAIRE

Kano,Cristiaini; Cardoso,Antonio Ismael Inácio; Bôas,Roberto L Villas

2012-01-01

Because of lack of information about phosphorus fertilization in lettuce from the standpoint of seed production, this study was undertaken. The work was carried out in Botucatu, São Paulo state, Brazil, from September 25, 2003 to February 19, 2004, in order to study the influence of crescents phosphorus rates on yield and quality of lettuce seeds, cultivar Verônica. The experimental design was randomized blocks with five treatments (0; 200; 400; 600 and 800 kg ha-1 of P2O5) and five replicati...

Effect of Different Elicitors and Preharvest Day Application on the Content of Phytochemicals and Antioxidant Activity of Butterhead Lettuce (Lactuca sativa var. capitata) Produced under Hydroponic Conditions.

Science.gov (United States)

Moreno-Escamilla, Jesús Omar; Alvarez-Parrilla, Emilio; de la Rosa, Laura A; Núñez-Gastélum, José Alberto; González-Aguilar, Gustavo A; Rodrigo-García, Joaquín

2017-07-05

The effect of four elicitors on phytochemical content in two varieties of lettuce was evaluated. The best preharvest day for application of each elicitor was chosen. Solutions of arachidonic acid (AA), salicylic acid (SA), methyl jasmonate (MJ), and Harpin protein (HP) were applied by foliar aspersion on lettuce leaves while cultivating under hydroponic conditions. Application of elicitors was done at 15, 7, 5, 3, or 1 day before harvest. Green lettuce showed the highest increase in phytochemical content when elicitors (AA, SA, and HP) were applied on day 7 before harvest. Similarly, antioxidant activity rose in all treatments on day 7. In red lettuce, the highest content of bioactive molecules occurred in samples treated on day 15. AA, SA, and HP were the elicitors with the highest effect on phytochemical content for both varieties, mainly on polyphenol content. Antioxidant activity also increased in response to elicitation. HPLC-MS showed an increase in the content of phenolic acids in green and red lettuce, especially after elicitation with SA, suggesting activation of the caffeic acid pathway due to elicitation.

The effect of growth conditions on flavonols and anthocyanins accumulation in green and red lettuce

Directory of Open Access Journals (Sweden)

Klaudia BRÜCKOVÁ

2016-12-01

Full Text Available The aim of the study was to investigate the effect of different growth conditions on anthocyanins and flavonols accumulation in leaves of green and red loose leaf lettuce (Lactuca sativa var. crispa. Lettuce plants were grown in three types of conditions, in greenhouse (I. variant, behind clear glass in field (II. variant and in open field conditions (III. variant. Estimation of anthocyanins and flavonols content was done by non-destructive measurements with optical fluorescence sensor Multiplex® 3 (Force-A, France. It was estimated that green lettuce varieties had a greater flavonols content compared to red lettuce varieties in all experimental variants. The highest level of flavonols was detected in leaves of green variety Zoltán (1.218 RU and in red lettuce had the highest amount of flavonols in variety Carmesi (1.095 RU. At the same time red lettuce varieties were characterized by higher anthocyanins content. Parameter anthocyanin index is correlated with visible red coloration of leaves. The highest content of anthocyanins was detected in variety Oakly (0.867 RU. Under the open field conditions was found statistically significant higher (P < 0.05 flavonols and anthocyanins level in both green and red lettuce leaves compared to greenhouse conditions. It may be connected with intensification of flavonoids biosynthesis and accumulation which normally stimulated by sun irradiation, especially UV-B radiation.

Vegetables as a Source of Dietary Fiber to Prevent Degenerative Diseases

Directory of Open Access Journals (Sweden)

Deddy Muchtadi

2001-04-01

Full Text Available For long time vegetables were thought only as sources of several vitamins; however, it has been shown that vegetables contain other component, which is also important for maintaining body's health, i.e., dietary fiber. Dietary fiber is a group of polysaccharides oan other polymers, which cannot be digested by upper gastro-intestinal system of human. Dietary fiber can be grouped as soluble and insoluble dietary fiber, showing in different physiological effect. Soluble dietary fiber (SDF is effective in preventing cardiovascular disease, while insoluble dietary fiber (IDF can prevent the development of colon cancer, diverticulosis as well as obesity.Local vegetables found to contain high SDF (higher than 3,06% db are: watercress, green bean, carrot, eggplant, lettuce, broccoli, spinach, string bean, and aubergine; while which contain high IDF (higher than 40,60% db are: winged bean, watercress, chinese leaves, katuk leaves, lettuce, green bean, broccoli, carrot and spinach. Cooking (i.e. boiling, steaming and pan frying decrease the IDF content of vegetables, while their SDF content is not affected by cooking treatments.

Functional Metagenomics of Escherichia coli O157:H7 Interactions with Spinach Indigenous Microorganisms during Biofilm Formation

Science.gov (United States)

Carter, Michelle Q.; Xue, Kai; Brandl, Maria T.; Liu, Feifei; Wu, Liyou; Louie, Jacqueline W.; Mandrell, Robert E.; Zhou, Jizhong

2012-01-01

The increase in foodborne outbreaks worldwide attributed to fresh fruit and vegetables suggests that produce may serve as an ecological niche for enteric pathogens. Here we examined the interaction of E. coli O157:H7 (EcO157) with spinach leaf indigenous microorganisms during co-colonization and establishment of a mixed biofilm on a stainless steel surface. Stainless steel surface was selected to mimic the surface of produce-processing equipment, where retention of foodborne pathogens such as EcO157 could serve as a potential source for transmission. We observed a positive effect of spinach-associated microbes on the initial attachment of EcO157, but an antagonistic effect on the EcO157 population at the later stage of biofilm formation. Metagenomic analyses of the biofilm community with the GeoChip revealed an extremely diverse community (gene richness, 23409; Shannon-Weiner index H, 9.55). Presence of EcO157 in the mixed biofilm resulted in a significant decrease in the community α-diversity (t test, Pbiofilm at 48 h (ANOVA, Pbiofilm is likely associated with its metabolic potential in utilizing spinach nutrients: the generation time of EcO157 in spinach lysates at 28°C is ∼ 38 min, which is comparable to that in rich broth. The significant decrease in the abundance of many genes involved in carbon, nitrogen, and phosphorus cycling in the EcO157-inoculated biofilms (t test, Pbiofilm species. PMID:22957052

Role of curli and plant cultivation conditions on Escherichia coli O157:H7 internalization into spinach grown on hydroponics and in soil.

Science.gov (United States)

Macarisin, Dumitru; Patel, Jitendra; Sharma, Vijay K

2014-03-03

Contamination of fresh produce could represent a public health concern because no terminal kill step is applied during harvest or at the processing facility to kill pathogens. In addition, once contaminated, pathogens may internalize into produce and be protected from disinfectants during the postharvest processing step. The objective of the current study was to determine the potential internalization of Escherichia coli O157:H7 into spinach roots and subsequent transfer to the edible parts. Because curli are involved in biofilm formation, we investigated whether their presence influence the internalization of E. coli O157:H7 into spinach. Further, the effect of the spinach cultivar on E. coli O157:H7 internalization was evaluated. Spinach plants were grown in contaminated soil as well as hydroponically to prevent mechanical wounding of the roots and inadvertent transfer of pathogens from the contamination source to the non-exposed plant surfaces. Results showed that E. coli O157:H7 could internalize into hydroponically grown intact spinach plants through the root system and move to the stem and leaf level. The incidence of internalization was significantly higher in hydroponically grown plants when roots were exposed to 7 log CFU/mL compared to those exposed to 5 log CFU/mL. The effect of cultivar on E. coli O157:H7 internalization was not significant (P>0.05) for the analyzed spinach varieties, internalization incidences showing almost equal distribution between Space and Waitiki, 49.06% and 50.94% respectively. Wounding of the root system in hydroponically grown spinach increased the incidence of E. coli O157:H7 internalization and translocation to the edible portions of the plant. Experimental contamination of the plants grown in soil resulted in a greater number of internalization events then in those grown hydroponically, suggesting that E. coli O157:H7 internalization is dependent on root damage, which is more likely to occur when plants are grown in soil

Effect of irradiation on kinetic behavior of Salmonella Typhimurium and Staphylococcus aureus in lettuce and damage of bacterial cell envelope

International Nuclear Information System (INIS)

Shim, Won-Bo; Je, Gil-Soo; Kim, Kyeongyeol; Mtenga, Adelard B.; Lee, Won-Gyeong; Song, Jeong-Un; Chung, Duck-Hwa; Yoon, Yohan

2012-01-01

This study evaluated effect of gamma irradiation on survival of Salmonella Typhimurium and Staphylococcus aureus on lettuce and damage of cell envelope. S. Typhimurium and S. aureus were inoculated on red leaf lettuce, and they were irradiated at 0, 0.5, 1, 1.5, 2, 2.5, and 3 kGy, and the samples were then stored at 7 and 25 °C for 7 days. Survival of S. Typhimurium and S. aureus were enumerated on xylose lysine deoxycholate agar and Baird–Parker agar, respectively. D 10 value (dose required to reduce 1 log CFU/leaf) was calculated, and kinetic parameters (maximum specific growth rate; μ max and lag phase duration; LPD) were calculated by the modified Gompertz model. In addition, cell envelope damage of the pathogens was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). D 10 values were 0.35 and 0.33 kGy for S. Typhimurium and S. aureus, respectively. During storage at 7 °C, S. Typhimurium and S. aureus had significant (P max , respectively. At 25 °C, cell counts of S. Typhimurium and S. aureus on the samples irradiated at 0 and 0.5 kGy increased (P max of both pathogens were higher in 0 kGy (1.08–2.27 log CFU/leaf/day) and 0.5 kGy (0.58–0.92 log CFU/leaf/day), and LPDs ranged from 1.53 to 3.14 day. SEM and TEM observations showed that cells irradiated at 1.5 and 3 kGy showed disrupted cell membrane. These results indicate that gamma irradiation could be a useful decontamination technology to improve food safety of lettuce by destroying cells of S. Typhimurium and S. aureus. - Highlights: ► Low dose of gamma irradiation destroyed cell envelope of the pathogens. ► Gamma irradiation decreased cell counts of the pathogens on lettuce. ► Gamma irradiation could be useful in improving food safety of lettuce.

Application of water-assisted ultraviolet light in combination of chlorine and hydrogen peroxide to inactivate Salmonella on fresh produce.

Science.gov (United States)

Guo, Shuanghuan; Huang, Runze; Chen, Haiqiang

2017-09-18

With the demand for fresh produce increases in recent decades, concerns for microbiological safety of fresh produce are also raised. To identify effective ultraviolet (UV) light treatment for fresh produce decontamination, we first determined the effect of three forms of UV treatment, dry UV (samples were treated by UV directly), wet UV (samples were dipped in water briefly and then exposed to UV), and water-assisted UV (samples were treated by UV while being immersed in agitated water) on inactivation of Salmonella inoculated on tomatoes and fresh-cut lettuce. In general, the water-assisted UV treatment was found to be the most effective for both produce items. Chlorine and hydrogen peroxide were then tested to determine whether they could be used to enhance the decontamination efficacy of water-assisted UV treatment and prevent transfer of Salmonella via wash water by completely eliminating it. Neither of them significantly enhanced water-assisted UV inactivation of Salmonella on tomatoes. Chlorine significantly improved the decontamination effectiveness of the water-assisted UV treatment for baby-cut carrots and lettuce, but not for spinach. In general, the single water-assisted UV treatment and the combined treatment of water-assisted UV and chlorine were similar or more effective than the chlorine washing treatment. In most of the cases, no Salmonella was detected in the wash water when the single water-assisted UV treatment was used to decontaminate tomatoes. In a few cases when Salmonella was detected in the wash water, the populations were very low,≤2CFU/mL, and the wash water contained an extremely high level of organic load and soil level. Therefore, the single water-assisted UV treatment could potentially be used as an environmentally friendly and non-chemical alternative to chlorine washing for tomatoes after validation in industrial scale. For lettuce, spinach and baby-cut carrots, the combined treatment of water-assisted UV treatment and chlorine

Structural and Sensory Characterization of Novel Sesquiterpene Lactones from Iceberg Lettuce.

Science.gov (United States)

Mai, Franziska; Glomb, Marcus A

2016-01-13

Lactuca sativa var. capitate (iceberg lettuce) is a delicious vegetable and popular for its mild taste. Nevertheless, iceberg lettuce is a source of bitter substances, such as the sesquiterpene lactones. Chemical investigations on the n-butanol extract led to the isolation of three novel sesquiterpene lactones. All compounds were isolated by multilayer countercurrent chromatography followed by preparative high-performance liquid chromatography. The structures were verified by means of spectroscopic methods, including NMR and mass spectrometry techniques. For the first time 11ß,13-dihydrolactucin-8-O-sulfate (jaquinelin-8-O-sulfate) was structurally elucidated and identified in plants. In addition, the sesquiterpene lactones cichorioside B and 8-deacetylmatricarin-8-O-sulfate were identified as novel ingredients of iceberg lettuce. Further flowering plants in the daisy family Asteraceae were examined for the above three compounds. At least one of the compounds was identified in nine plants. The comparison between the lettuce butt end and the leaves of five types of the Cichorieae tribe showed an accumulation of the compounds in the butt end. Further experiments addressed the impact of sesquiterpene lactones on color formation and bitter taste.

Sequential fractionation and differences in binding forms of risk elements in spinach biomass

Czech Academy of Sciences Publication Activity Database

Pavlíková, D.; Pavlík, Milan; Vašíčková, Soňa; Száková, J.; Tlustoš, P.; Balík, J.

2005-01-01

Roč. 12, 1/2 (2005), s. 101-108 ISSN 1231-7098 R&D Projects: GA MZe(CZ) QF4063 Institutional research plan: CEZ:AV0Z40550506 Keywords : sequential extraction * spinach * risk elements Subject RIV: CC - Organic Chemistry

Zooming in on the lettuce genome: species relationships in Lactuca s.l., inferred from chromosomal and molecular characters

OpenAIRE

Koopman, W.J.M.

2002-01-01

Lactuca sativa (cultivated lettuce) is the world's most important leafy salad vegetable. Apart from L. sativa , the genus Lactuca contains ca. 75 wild species, potentially useful to improve, for example, taste, texture, and disease resistance of cultivated lettuce. The wild species L. serriola (Prickly Lettuce), L. saligna (Least Lettuce), and L. virosa (Great...

East Europe Report

Science.gov (United States)

1987-01-08

Onions 70.8 Morello cherries 69.6 Green onions 99.0 Plums 91.7 Garlic 99.4 Apricots 64.8 Common lettuce 94.4 Peaches 67.6 Spinach 47.3 Quince 99.6...been developed and this has been named Druzhba [Friendship]. And from our joint selection work, we already have two early hybrids of grain corn with

Cronograma de amostragem de alface cultivada em hidroponia para ajuste de curvas de crescimento vegetativo Sampling chronology of hydroponics lettuce plants for adjusting vegetative growth curves

Directory of Open Access Journals (Sweden)

Sidinei José Lopes

2007-10-01

Full Text Available O objetivo deste trabalho foi determinar o cronograma de amostragem de plantas de alface hidropônica, para ajuste de curvas de crescimento durante o período vegetativo. Foram realizados dois cultivos de alface, variedade Regina, de 8/9/2004 a 19/11/2004 (primavera/verão e 22/2/2005 a 24/5/2005 (verão/outono, em estufas de plástico do Dep. de Fitotecnia, da UFSM, Santa Maria, RS. A partir do ajuste do modelo co-seno com amostragem diária, registrada como padrão, diferentes intervalos entre as amostragens foram simulados para o ajuste do mesmo modelo. A fim de se encontrar o intervalo adequado, foi comparada a variância de falta de ajuste do modelo de amostragem diária com as variâncias de falta de ajuste dos modelos com diferentes intervalos de amostragens pelo teste F. Os cronogramas de amostragens para ajuste de curvas de crescimento de plantas de alface sob hidroponia, para experimentos de primavera/verão e verão/outono, possuem intervalos iguais a dois dias, para fitomassa seca total da planta e da folha; intervalos de quatro dias, para fitomassa de raiz; e, diariamente, para área foliar.The objective of this work was to determinate a sampling chronology to adjust lettuce hidroponic growth curves during its vegetative development. The variety Regina was grown from September 8, 2004 until November 19, 2004 (spring/summer and February 22, 2005 until May 24, 2005 (summer/fall. Plants were placed inside a plastic covered greenhouse in Santa Maria, RS, Brazil. Based on the adjusted cosine model, daily samples were taken as standard and different sampling intervals were simulated in order to better adjust the same model. To estimate de adequate sampling interval a comparison was conducted between the variance of lack of adjustment of the daily sampling with the variance of lack of adjustment of different samplings intervals using an F test. Sampling chronograms for adjusting crop growth curves of hydroponics lettuce plants for both

Fertilization effect on yield and nitrate content in organically produced lettuce

Directory of Open Access Journals (Sweden)

Čabilovski Ranko

2010-01-01

Full Text Available The effect of applying different organic materials (OM on yield and nitrate content in lettuce was studied in a field experiment on a farm registered for organic production during two years (2007 and 2008. Treatments were: farmyard manure (ST, guano (G, milled soybean (Glicine hispida seed (S; milled forage pea (Pisum sativum seed (P and control treatment (q. Biannual average fresh matter (FM yield of lettuce on fertilized plots ranges from 45.44 t ha-1 (P to 46,38 t ha-1 (ST and was significantly higher than fresh matter yield of the control (39.34 t ha-1, while the differences between fertilized treatments were not significant. Nitrate content in the fresh mass of lettuce in all treatments in both years was below the maximum allowed content (2.500 mg kg-1 regulated by the EU (Commission Regulation (EC, No 466/2001. In both years, the lowest nitrate content in the fresh mass of lettuce was recorded with the control treatment (q and highest with S treatment. Nitrate contents with G, P and S treatments were significantly higher than that recorded with FYM and q, whereas the differences between FYM and q were not significant in either the first or the second year of research. Linear correlation (r = 0.83**in 2007; r = 0.91** in 2008 was found between the content of mineral N in the soil and nitrate content in the FM of lettuce at the moment of harvesting in both years. .

Health effect of vegetable-based diet: lettuce consumption improves cholesterol metabolism and antioxidant status in the rat.

Science.gov (United States)

Nicolle, Catherine; Cardinault, Nicolas; Gueux, Elyett; Jaffrelo, Lydia; Rock, Edmond; Mazur, Andrzej; Amouroux, Pierre; Rémésy, Christian

2004-08-01

It is often assumed that fruits and vegetables contribute to protect against degenerative pathologies such as cardiovascular diseases. Besides epidemiological observations, scientific evidences for their mechanism of action are scarce. In the present study, we investigated the mean term and post-prandial effects of lettuce ingestion on lipid metabolism and antioxidant protection in the rat. Feeding rats a 20% lettuce diet for 3 weeks resulted in a decrease cholesterol LDL/HDL ratio and a marked decrease of liver cholesterol levels (-41%). Concurrently, fecal total steroid excretion increased (+44%) and apparent absorption of dietary cholesterol was significantly depressed (-37%) by the lettuce diet. Lettuce diet also displayed an improvement of vitamin E/TG ratio in plasma and limited lipid peroxidation in heart as evidenced by TBARS. In post-prandial experiment, lettuce intake significantly increased both ascorbic acid and alpha-tocopherol plasma levels which contribute to improve plasma antioxidant capacity within 2 h of consumption. Other lipid-soluble antioxidants (lutein and vitamin E) may also improve the plasma antioxidant capacity. Lettuce consumption increases the total cholesterol end-products excretion and improves antioxidant status due to the richness in antioxidants (vitamins C, E and carotenoids). In our model, lettuce clearly shows a beneficial effect on lipid metabolism and on tissue oxidation. Therefore regular consumption of lettuce should contribute to improve protection against cardiovascular diseases. Copyright 2003 Elsevier Ltd.

Laboratory and semi-field evaluation of Beauveria bassiana (Ascomycota: Hypocreales) against the lettuce aphid, Nasonovia ribisnigri (Hemiptera: Aphididae)

DEFF Research Database (Denmark)

Shrestha, Govinda; Enkegaard, Annie; Steenberg, Tove

2015-01-01

The lettuce aphid, Nasonovia ribisnigri (Mosley), is an economically important pest of lettuce worldwide. The entomopathogenic fungus Beauveria bassiana strain GHA has recently been reported as a potential biocontrol candidate for use against the lettuce aphid. This study provides information...... on the mortality inflicted by B. bassiana when applied against different life stages of the lettuce aphid under laboratory conditions and how fungus infection affects the aphid fecundity. In addition, temporal changes in persistence of fungus inoculum applied to foliage of young lettuce plants under semi......-field conditions was analysed. Immature life stages were generally the least susceptible to fungal infection and the susceptibility of all stages was dose-dependent, with the highest mortality occurring at the highest dose. B. bassiana significantly affected the rate of nymph production by the lettuce aphid...

Photoprotection vs. Photoinhibition of Photosystem II in Transplastomic Lettuce (Lactuca sativa) Dominantly Accumulating Astaxanthin.

Science.gov (United States)

Fujii, Ritsuko; Yamano, Nami; Hashimoto, Hideki; Misawa, Norihiko; Ifuku, Kentaro

2016-07-01

Transplastomic (chloroplast genome-modified; CGM) lettuce that dominantly accumulates astaxanthin grows similarly to a non-transgenic control with almost no accumulation of naturally occurring photosynthetic carotenoids. In this study, we evaluated the activity and assembly of PSII in CGM lettuce. The maximum quantum yield of PSII in CGM lettuce was <0.6; however, the quantum yield of PSII was comparable with that in control leaves under higher light intensity. CGM lettuce showed a lower ability to induce non-photochemical quenching (NPQ) than the control under various light intensities. The fraction of slowly recovering NPQ in CGM lettuce, which is considered to be photoinhibitory quenching (qI), was less than half that of the control. In fact, 1 O 2 generation was lower in CGM than in control leaves under high light intensity. CGM lettuce contained less PSII, accumulated mostly as a monomer in thylakoid membranes. The PSII monomers purified from the CGM thylakoids bound echinenone and canthaxanthin in addition to β-carotene, suggesting that a shortage of β-carotene and/or the binding of carbonyl carotenoids would interfere with the photophysical function as well as normal assembly of PSII. In contrast, high accumulation of astaxanthin and other carbonyl carotenoids was found within the thylakoid membranes. This finding would be associated with the suppression of photo-oxidative stress in the thylakoid membranes. Our observation suggests the importance of a specific balance between photoprotection and photoinhibition that can support normal photosynthesis in CGM lettuce producing astaxanthin. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Sensory analysis of calcium-biofortified lettuce

Science.gov (United States)

Vegetables represent an attractive means of providing increased calcium nutrition to the public. In this study, it was demonstrated that lettuce expressing the deregulated Arabidopsis H(+)/Ca(2+) transporter sCAX1 (cation exchanger 1) contained 25-32% more calcium than controls. These biofortified l...

Organellar and cytosolic localization of four phosphoribosyl diphosphate synthase isozymes in spinach

DEFF Research Database (Denmark)

Krath, Britta N.; Hove-Jensen, Bjarne

1999-01-01

Four cDNAs encoding phosphoribosyl diphosphate (PRPP) synthase were isolated from a spinach (Spinacia oleracea) cDNA library by complementation of an Escherichia coli Δprs mutation. The four gene products produced PRPP in vitro from ATP and ribose-5-phosphate. Two of the enzymes (isozymes 1 and 2...

Nutritional and taste characteristics of low-potassium lettuce developed for patients with chronic kidney diseases

OpenAIRE

Yoshida, Takuya; Sakuma, Kozue; Kumagai, Hiromichi

2014-01-01

Dietary potassium restriction is recommended for chronic kidney disease (CKD) patients with hyperkalemia. Boiling or soaking vegetables in water is known to decrease their potassium content. However, these methods can also reduce the quantity of other nutrients. Recently, low-potassium (LK) lettuce has been developed for CKD patients with hyperkalemia. This study compared the potassium content, other nutritional values, and taste characteristics of LK lettuce with those of normal lettuce. The...

Fluorescence hyperspectral imaging technique for the foreign substance detection on fresh-cut lettuce

Science.gov (United States)

Nondestructive methods based on fluorescence hyperspectral imaging (HSI) techniques were developed in order to detect worms on fresh-cut lettuce. The optimal wavebands for detecting worms on fresh-cut lettuce were investigated using the one-way ANOVA analysis and correlation analysis. The worm detec...

Effect of green spinach (Amaranthus tricolor L.) and tomato (Solanum lycopersicum) addition in physical, chemical, and sensory properties of marshmallow as an alternative prevention of iron deficiency anemia

Science.gov (United States)

Yudhistira, B.; Affandi, D. R.; Nusantari, P. N.

2018-01-01

Iron deficiency anemia is the most common nutritional disorder in the world. Consuming vegetable which contain iron, including spinach, is an alternative to fulfill iron requirement. Fe will be more easily absorbed in the presence of vitamin C. Tomato is one of vitamin C source that can be used. Spinach can be applied into confectionary products in the form of marshmallow. This research aimed to find out the physical, chemical and sensory properties of green spinach Marshmallow in addition of Tomato, the best formula, and define the category of nutrition contents based on Acuan Label Gizi (ALG). This study used a completely randomized design (CRD) with one factor that was different proportion of spinach:tomato (75%: 25%; 50%: 50%; 25%: 75%). The data were analyzed using One Way Anova with 5% significance level. The result of this study showed that the difference of spinach and tomato proportion affect tensile strength, moisture, ash content, Fe content, crude fiber, vitamin C, color and marshmallow’s flavor. Best marshmallow formulation of 25% spinach in addition of 75% tomato had Fe content of 1.159 mg/100g and vitamin C of 44 mg/100g.

Antineurodegenerative effect of phenolic extracts and caffeic acid derivatives in romaine lettuce on neuron-like PC-12 cells.

Science.gov (United States)

Im, Sung-Eun; Yoon, Hyungeun; Nam, Tae-Gyu; Heo, Ho Jin; Lee, Chang Yong; Kim, Dae-Ok

2010-08-01

In recent decades, romaine lettuce has been one of the fastest growing vegetables with respect to its consumption and production. An understanding is needed of the effect of major phenolic phytochemicals from romaine lettuce on biological protection for neuron-like PC-12 cells. Phenolics in fresh romaine lettuce were extracted, and then its total phenolics and total antioxidant capacity were measured spectrophotometrically. Neuroprotective effects of phenolic extract of romaine lettuce and its pure caffeic acid derivatives (caffeic, chicoric, chlorogenic, and isochlorogenic acids) in PC-12 cells were evaluated using two different in vitro methods: lactate dehydrogenase release and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assays. Total phenolics and total antioxidant capacity of 100 g of fresh romaine lettuce averaged 22.7 mg of gallic acid equivalents and 31.0 mg of vitamin C equivalents, respectively. The phenolic extract of romaine lettuce protected PC-12 cells against oxidative stress caused by H(2)O(2) in a dose-dependent manner. Isochlorogenic acid, one of the phenolics in romaine lettuce, showed stronger neuroprotection than the other three caffeic acid derivatives also found in the lettuce. Although romaine lettuce had lower levels of phenolics and antioxidant capacity compared to other common vegetables, its contribution to total antioxidant capacity and antineurodegenerative effect in human diets would be higher because of higher amounts of its daily per capita consumption compared to other common vegetables.

Cross contamination of Escherichia coli O157:H7 between lettuce and wash water during home-scale washing.

Science.gov (United States)

Jensen, Dane A; Friedrich, Loretta M; Harris, Linda J; Danyluk, Michelle D; Schaffner, Donald W

2015-04-01

Lettuce and leafy greens have been implicated in multiple foodborne disease outbreaks. This study quantifies cross contamination between lettuce pieces in a small-scale home environment. A five-strain cocktail of relevant Escherichia coli O157:H7 strains was used. Bacterial transfer between single inoculated lettuce leaf pieces to 10 non-inoculated lettuce leaf pieces that were washed in a stainless steel bowl of water for 30 s, 1 min, 2 min, and 5 min was quantified. Regardless of washing time, the wash water became contaminated with 90-99% of bacteria originally present on the inoculated lettuce leaf piece. The E. coli O157:H7 concentration on initially inoculated leaf pieces was reduced ∼ 2 log CFU. Each initially uncontaminated lettuce leaf piece had ∼ 1% of the E. coli O157:H7 from the inoculated lettuce piece transferred to it after washing, with more transfer occurring during the shortest (30 s) and longest (5 min) wash times. In all cases the log percent transfer rates were essentially normally distributed. In all scenarios, most of the E. coli O157:H7 (90-99%) transferred from the inoculated lettuce pieces to the wash water. Washing with plain tap water reduces levels of E. coli O157:H7 on the inoculated lettuce leaf pieces, but also spreads contamination to previously uncontaminated leaf pieces. Copyright © 2014 Elsevier Ltd. All rights reserved.

Purification and Characterization of Polyphenol Oxidase, Peroxidase and Lipoxygenase from Freshly Cut Lettuce (L. sativa

Directory of Open Access Journals (Sweden)

Vural Gökmen

2011-01-01

Full Text Available Enzymatic reactions taking place in minimally processed vegetables are considered as a major problem, because they adversely affect sensorial and nutritional quality. Polyphenol oxidase (PPO, peroxidase (POD and lipoxygenase (LOX from lettuce were purified on a column packed with positively charged diethylaminoethyl (DEAE cellulose by applying pH gradient elution from pH=4.0 to 9.0. The main purified fractions (PPO1 and PPO4, POD1 and POD2, LOX1 and LOX2 were characterized for enzyme concentration-reaction rate relationship, thermal stability, pH activity and kinetic parameters. Kinetic properties of each isoform were considerably different. Cysteine was found as the most effective inhibitor of both fractions of PPO. Kinetic parameters of lettuce POD were presented using guaiacol at various H2O2 concentrations. β-carotene directly influences lettuce LOX in the reaction medium available for the catalytic conversion of linoleic acid into hydroperoxides. Ascorbic and oxalic acids appear as effective PPO inhibitors, protecting phenolic compounds against oxidation in lettuce. Understanding the characteristics of deteriorative enzymes becomes important to maintain suitable conditions for fresh-like quality of lettuce. The results can be useful to keep the nutritional quality of minimally processed lettuce during shelf-life.

76 FR 81468 - Notice of Decision to Authorize the Importation of Shredded Lettuce From Egypt Into the...

Science.gov (United States)

2011-12-28

...] Notice of Decision to Authorize the Importation of Shredded Lettuce From Egypt Into the Continental... fresh shredded lettuce from Egypt. Based on the findings of a pest risk analysis, which we made... introducing or disseminating plant pests or noxious weeds via the importation of fresh shredded lettuce from...

Influence of nitrogen and phosphorus sources on mycorrhizal lettuces under organic farming

Science.gov (United States)

Scotti, Riccardo; Seguel, Alex; Cornejo, Pablo; Rao, Maria A.; Borie, Fernando

2010-05-01

Arbuscular mycorrhizal fungi (AMF) develop symbiotic associations with plants roots. These associations are very common in the natural environment and can provide a range of benefits to the host plant. AMF improve nutrition, enhance resistance to soil-borne pests and disease, increase resistance to drought and tolerance to heavy metals, and contribute to a better soil structure. However, agricultural intensive managements, such as the use of mineral fertilizes, pesticides, mouldboard tillage, monocultures and use of non-mycorrhizal crops, are detrimental to AMF. As a consequence, agroecosystems are impoverished in AMF and may not provide the full range of benefits to the crop. Organic farming systems may be less unfavourable to AMF because they exclude the use of water-soluble fertilisers and most pesticides, and generally they plan diverse crop rotations. The AMF develop the most common type of symbiosis in nature: about 90% of the plants are mycorrhizal and many agricultural crops are mycorrhizal. One of more mycorrhizal crops is lettuce, that is very widespread in intensive agricultural under greenhouse. Therefore, cultivated lettuce is know to be responsive to mycorrhizal colonization which can reach 80% of root length and contribute to phosphorus and nitrogen absorption by this plant specie. For this work four different lettuce cultivars (Romana, Milanesa, Grande Lagos and Escarola) were used to study mycorrhization under organic agricultural system, supplying compost from agricultural waste (1 kg m-2) as background fertilization for all plots, red guano as phosphorus source (75 U ha-1 and 150 U ha-1 of P2O5), lupine flour as nitrogen source (75 and 150 U/ha of N) and a combination of both. Lettuce plants were cultivated under greenhouse and after two months of growing, plants were harvested and dried and fresh weight of lettuce roots and shoots were evaluated. The number of spores, percentage of colonization, total mycelium and glomalin content were also

Adherence of curli producing Shiga-toxigenic Escherichia coli to baby spinach leaves

Science.gov (United States)

Cellular appendages, such as curli fibers have been suggested to be involved in STEC persistence in fresh produce as these curli are critical in biofilm formation and adherence to animal cells. We determined the role of curli in attachment of STEC on spinach leaves. The curli expression by wild-ty...

A detailed linkage map of lettuce based on SSAP, AFLP and NBS markers

NARCIS (Netherlands)

Syed, H.; Sorensen, A.P.; Antonise, R.; van de Wiel, C.; van der Linden, C.G.; van 't Westende, W.; Hooftman, D.A.P.; den Nijs, J.C.M.; Flavell, A.J.

2006-01-01

Abstract Molecular markers based upon a novel lettuce LTR retrotransposon and the nucleotide binding site-leucine-rich repeat (NBS-LRR) family of disease resistance-associated genes have been combined with AFLP markers to generate a 458 locus genetic linkage map for lettuce. A total of 187

Accuracy, reliability, and timing of visual evaluations of decay in fresh-cut lettuce

Science.gov (United States)

Visual assessments are used for evaluating the quality of food products, such as fresh-cut lettuce packaged in bags with modified atmosphere. We have compared the accuracy and the reliability of visual evaluations of decay on fresh-cut lettuce performed with experienced and inexperienced raters. In ...

Nondestructive phenotyping of lettuce plants in early stages of development with optical sensors

Science.gov (United States)

Rapid development of plants is important for the production of ‘baby-leaf’ lettuce that is harvested when plants reach the four- to eight-leaf stage of growth. However, environmental factors, such as high or low temperature, or elevated concentrations of salt, inhibit lettuce growth. Therefore, nond...

Fate of [14C]-zineb on lettuce plants

International Nuclear Information System (INIS)

Vonk, J.W.

1976-01-01

[1,2- 14 C]-zinc ethylenebisdithiocarbamate (zineb) was prepared and applied in droplets to leaves of lettuce plants. In aqueous suspension zineb decomposes mainly into ethylenethiourea (ETU) and 5,6-dihydro-3H-imidazo[2,1-C]-1,2,4-dithiazole-3-thione (DIDT). Lettuce plants were harvested 0,1,3,7,14 and 21 days after treatment and analysed. A high proportion of radioactivity remained on the surface of the plant and could be washed off. The following identified products were present: unchanged zineb, ETU, DIDT, 2-imidazoline and ethyleneurea. The ETU residue disappeared within 7 days, while 2-imidazoline and ethyleneurea were formed gradually. Radioactivity inside the plant consisted mostly of ethyleneurea: no ETU was present. (author)

Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

International Nuclear Information System (INIS)

He Suyan; Li Yunfei

2008-01-01

The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1 deg. C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data

Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

Energy Technology Data Exchange (ETDEWEB)

He, Su-Yan [School of Mechanical and Electrical Engineering, Qingdao University, Qingdao 266071 (China); Li, Yun-Fei [Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University (China)

2008-10-15

The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1{sup o}C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data. (author)

Experimental study and process parameters analysis on the vacuum cooling of iceberg lettuce

Energy Technology Data Exchange (ETDEWEB)

He Suyan [School of Mechanical and Electrical Engineering, Qingdao University, Qingdao 266071 (China)], E-mail: hesuyan67829@sina.com; Li Yunfei [Department of Food Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University (China)

2008-10-15

The vacuum cooling of iceberg lettuce was described in this paper. Based on the energy and mass balance, a mathematical model was developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of iceberg lettuce. The temporal trends of total system pressure, produce temperature such as surface temperature, center temperature, mass-average temperature, the weight loss of iceberg lettuce during vacuum cooling were predicted. Validation experimentation is achieved in the designed vacuum cooler. The experimental data were compared with the simulation results. It was found that the differences of the temperature between the simulation and the experiments were within 1 deg. C. The amount of water evaporated from the iceberg lettuce by simulation was 3.32% during the whole vacuum cooling, while the tested water loss rate was 2.97%, the maximal deviation of weight loss was within 0.59%. The simulation results agreed well with the experimental data.

Researches Regarding the Influence of Cold Storage on the Chlorophyll Content in Lettuce

Directory of Open Access Journals (Sweden)

Iuliana Cretescu

2014-05-01

Full Text Available The aim of the present investigations was to determine the effect of the cold storage period on the content of chlorophylls in the leaves of lettuce and arugula (rucola. The research material consisted in two types of lettuce (Lactuca sativa L. var. capitata; Lactuca sativa L. var. crispa and arugula (Eruca sativa purchased from supermarkets in Timisoara. The quantitative determination of chlorophyll pigments in leaves (SPAD was made by chlorophyll meter (SPAD 502 Konica-Minolta. During the few days cold storage at a temperature of 4ºC, the content of chlorophyll in the leaf significantly decreased, compared with that in the control group. After 3 days of cold storage arugula and lettuce (Lactuca sativa var. capitata values of chlorophyll content differ statistically very significantly (p<0.001 from the values found in the control group which for lettuce (Lactuca sativa L. var. crispa differs statistically significant (p < 0.05.

Effect of Root-Zone Moisture Variations on Growth of Lettuce and Pea Plants

Science.gov (United States)

Ilieva, Iliana; Ivanova, Tania

2008-06-01

Variations in substrate moisture lead to changes in water and oxygen availability to plant roots. Ground experiments were carried out in the laboratory prototype of SVET-2 Space Greenhouse to study the effect of variation of root-zone moisture conditions on growth of lettuce and pea plants. The effect of transient increase (for 1 day) and drastic increase (waterlogging for 10 days) of substrate moisture was studied with 16-day old pea and 21-day old lettuce plants respectively. Pea height and fresh biomass accumulation were not affected by transient substrate moisture increase. Net photosynthetic rate (Pn) of pea plants showed fast response to substrate moisture variation, while chlorophyll content did not change. Drastic change of substrate moisture suppressed lettuce Pn, chlorophyll biosynthesis and plant growth. These parameters slowly recovered after termination of waterlogging treatment but lettuce yield was greatly affected. The results showed that the most sensitive physiological parameter to substrate moisture variations is photosynthesis.

Radioactive contaminants in raw materials and foodstuffs of plant origin

International Nuclear Information System (INIS)

Stankovicj, S.; Krainchanicj, M.; Stankovicj, A.

1990-01-01

The paper concentrates on the results of activity level of radioactive caesium 134 and 137 in the samples of raw materials (barley, oats, soybean, sunflower, pumpkin seed, hops, shreded sugar beet, maize), animal feedstuffs (alfalfa, alfalfa meal, rape, concentrates fed to chickens, pigs or bpvines, dry turnip shreds) and foodstuff of plant origin (lettuce, spinach, cabbage, carrot, celery, cucumber, tomato, olives, sesame). All samples - produced locally on the major part but also including some imported stuff -have been subjected to continuous gamma spectrometry starting with the Chernobyl accident in 1986 through 1989. The highest activity of caesium was recorded in the samples of animal feedstuffs (alfalfa, alfalfa meal, rape) in the years 1986 and 1987. In time, however, the activity tends to drop considerably. (author) 4 refs.; 3 tabs

Characteristics of prickly lettuce seed oil in relation to methods of extraction.

Science.gov (United States)

Ramadan, A A

1976-01-01

Samples of seed oil of prickly lettuce (Lactuca Sacriola oleifera) which had been obtained by pressing or by extracting with acetone, ethyl ether, petroleum ether or carbon tetrachloride were analysed for the following parameters: viscosity, saponification number, iodine number, thiocyanogen value, unsaponifiable matter, free fatty acids, peroxide number and fatty acid composition. The different parameters varied in part considerably in relation to the method of production (pressing or solvent extraction) and to the solvent. It is tried to interprete these relationships.

Genetics of the partial resistance against race 2 of Verticillium dahliae in lettuce

Science.gov (United States)

Lettuce (Lactuca sativa L.) production on the Coastal California is threatened by Verticillium wilt, a soil borne fungal disease caused by Verticillium dahliae that diminishes yield and quality. Two races of V. dahliae were identified on lettuce, race 1 and race 2. Complete resistance to race 1 is c...

Multispectral imaging as a potential tool for seed health testing of spinach (Spinacia oleracea L.)

DEFF Research Database (Denmark)

Olesen, M. Halkjaer; Carstensen, Jens Michael; Boelt, B.

2011-01-01

Seed health tests are time consuming and require substantial training for characterization of pathogenic fungi on seed. A new approach to use a multispectral vision system for identifying surface properties of different fungal infections has been tested in spinach (Spinacia oleracea L.) at Aarhus...... University. Our study demonstrates that multispectral imaging with wavelengths ranging from 395-970 nm can be used to distinguish between uninfected spinach seeds and seeds infected with Verticillium spp., Fusarium spp., Stemphylium botryosum, Cladosporium spp. and Alternaria alternata. Analytical separation...... based on mean pixel intensity, Canonical Discriminant Analysis (CDA) and classification by Jeffries-Matusita (JM) distance illustrates that a combination of Near Infrared spectra (NIR) and Visual spectra (VIS) is able to identify uninfected seeds from infected seeds ranging from 80-100%. Classification...

Optimal control of nitrate in lettuce by a hybrid approach: differential evolution and adjustable control weight gradient algorithms

NARCIS (Netherlands)

Lopez Cruz, I.L.; Willigenburg, van L.G.; Straten, van G.

2003-01-01

Abstract Since high concentration levels of nitrate in lettuce and other leafy vegetables are undesirable, cultivation of lettuce according to specified governmental regulations is currently an important issue. Therefore, methods are sought in order to produce a lettuce crop that allow maximization

Recognition of Histo-Blood Group Antigen-Like Carbohydrates in Lettuce by Human GII.4 Norovirus.

Science.gov (United States)

Gao, Xiang; Esseili, Malak A; Lu, Zhongyan; Saif, Linda J; Wang, Qiuhong

2016-05-15

Human norovirus (HuNoV) genogroup II genotype 4 (GII.4) strains account for about 80% of the gastroenteritis outbreaks in the United States. Contaminated food is a major transmission vehicle for this virus. In humans, pigs, and oysters, histo-blood group antigens (HBGAs) act as attachment factors for HuNoVs. In lettuce, although the virus-like particles (VLPs) of a GII.4 HuNoV were found to bind to cell wall carbohydrates, the exact binding site has not been investigated. Here, we show the presence of HBGA-like carbohydrates in the cell wall of lettuce. The digestion of lettuce leaves with cell wall-degrading enzymes exposed more binding sites and significantly increased the level of binding of GII.4 HuNoV VLPs. Competition assays showed that both the HBGA monoclonal antibody, recognizing the H type, and plant lectins, recognizing α-l-fucose in the H type, effectively inhibited VLP binding to lettuce tissues. Lettuce cell wall components were isolated and their NoV VLP binding characteristics were tested by enzyme-linked immunosorbent assays. The binding was inhibited by pretreatment of the lettuce cell wall materials with α-1,2-fucosidase. Collectively, our results indicate that H-type HBGA-like carbohydrates exist in lettuce tissues and that GII.4 HuNoV VLPs can bind the exposed fucose moiety, possibly in the hemicellulose component of the cell wall. Salad crops and fruits are increasingly recognized as vehicles for human norovirus (HuNoV) transmission. A recent study showed that HuNoVs specifically bind to the carbohydrates of the lettuce cell wall. Histo-blood group antigens (HBGAs) are carbohydrates and are known as the attachment factors for HuNoV infection in humans. In this study, we show the presence of HBGA-like carbohydrates in lettuce, to which HuNoVs specifically bind. These results suggest that specifically bound HuNoVs cannot be removed by simple washing, which may allow viral transmission to consumers. Our findings provide new information needed

Hygienic-sanitary quality of vegetables and evaluation of treatments for the elimination of indigenous E. coli and E. coli O157:H7 from the surface of leaves of lettuce (Lactuca sativa L.)

OpenAIRE

Santos, Ytana Oliveira; Almeida, Rogeria Comastri de Castro; Guimarães, Alaise Gil; Almeida, Paulo Fernando de

2010-01-01

p.1083-1089 The purpose of this study is to evaluate the hygienic-sanitary quality of vegetables and irrigation water and assess the effectiveness of lemon juice and vinegar in reducing E. coli strains inoculated on lettuce. One hundred and forty samples of vegetables and 45 samples of irrigation water were investigated for thermotolerant coliforms and Salmonella spp. In order to verify the effectiveness of natural household sanitizers in reducing E. coli in inoculated lettuce, four treatm...

Genetic dissection of nonhost resistance of wild lettuce, Lactuca saligna, to downy mildew

NARCIS (Netherlands)

Zhang, N.

2008-01-01

Lettuce downy mildew is the most destructive disease in lettuce (Lactuca spp.) cultivation and is caused by Bremia lactucae. The successful cross between its host L. sativa and the nonhost, L. saligna, and offers a rare chance to study the genetics of the nonhost resistance. From a set of 29

Assessing nitrogen supply potential and influence on growth of lettuce and amaranthus of different aged composts

International Nuclear Information System (INIS)

Akhtar, M.J.; Young, I.; Irvine, R.J.; Sturrock, C.

2010-01-01

This study assessed the potential of different composts at different maturity stages to supply N and their effect on the vegetative growth of lettuce and Amaranthus. Five composts aged 1, 3, 6, 9, and 12 months, were mixed with soil at the rate of 5%, 10% and 15% then seeded with lettuce and Amaranthus. Results showed that 1, 3 and 6 month aged composts had a negative effect on plant height of lettuce and Amaranthus as 1-15.78% and 4.78 to 29.45% decrease in plant height over control was recorded respectively. On the other hand 9 and 12 month aged composts had a significant positive effect on plant height of lettuce and Amaranthus where 43.48% and 34.8% increase over control was recorded with the application of 15% of 12 month aged compost respectively. A similar effect was observed on fresh biomass of both lettuce and Amaranthus where a 386% and 59.43% increase over control was recorded with the application of 15% of 12 month aged compost respectively. One and three month aged composts revealed a negative effect on N absorption by lettuce whereas 1, 3, 6 and 9 month aged composts had a negative effect on N absorption by Amaranthus. 30.39% and 21.48% increases over control in N absorption by lettuce and Amaranthus respectively were recorded with the application of 15% of 12 month aged compost. (author)

Ladybugs and Lettuce Leaves. Teachers' Manual.

Science.gov (United States)

Barnes, Tracy; And Others

This is a guide for use with "Ladybugs and Lettuce Leaves" activity cards which are activities for elementary school students (grades 4 to 6) focusing on gardening. It includes educational objectives for each topic as well as lists of vocabulary words, comments, questions for discussion, additional activities, and resources. An interdisciplinary…

Dielectric barrier discharge atmospheric cold plasma inhibits Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus in Romaine lettuce.

Science.gov (United States)

Min, Sea C; Roh, Si Hyeon; Niemira, Brendan A; Sites, Joseph E; Boyd, Glenn; Lacombe, Alison

2016-11-21

The present study investigated the effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inactivation of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Tulane virus (TV) on Romaine lettuce, assessing the influences of moisture vaporization, modified atmospheric packaging (MAP), and post-treatment storage on the inactivation of these pathogens. Romaine lettuce was inoculated with E. coli O157:H7, Salmonella, L. monocytogenes (~6logCFU/g lettuce), or TV (~2logPFU/g lettuce) and packaged in either a Petri dish (diameter: 150mm, height: 15mm) or a Nylon/polyethylene pouch (152×254mm) with and without moisture vaporization. Additionally, a subset of pouch-packaged leaves was flushed with O 2 at 5% or 10% (balance N 2 ). All of the packaged lettuce samples were treated with DACP at 34.8kV for 5min and then analyzed either immediately or following post-treatment storage for 24h at 4°C to assess the inhibition of microorganisms. DACP treatment inhibited E. coli O157:H7, Salmonella, L. monocytogenes, and TV by 1.1±0.4, 0.4±0.3, 1.0±0.5logCFU/g, and 1.3±0.1logPFU/g, respectively, without environmental modifications of moisture or gas in the packages. The inhibition of the bacteria was not significantly affected by packaging type or moisture vaporization (p>0.05) but a reduced-oxygen MAP gas composition attenuated the inhibition rates of E. coli O157:H7 and TV. L. monocytogenes continued to decline by an additional 0.6logCFU/g in post-treatment cold storage for 24h. Additionally, both rigid and flexible conventional plastic packages appear to be suitable for the in-package decontamination of lettuce with DACP. Published by Elsevier B.V.

Arsenic uptake by lettuce from As-contaminated soil remediated with Pteris vittata and organic amendment.

Science.gov (United States)

de Oliveira, Letuzia M; Suchismita, Das; Gress, Julia; Rathinasabapathi, Bala; Chen, Yanshan; Ma, Lena Q

2017-06-01

Leaching of inorganic arsenic (As) from chromated copper arsenate (CCA)-treated wood may elevate soil As levels. Thus, an environmental concern arises regarding As accumulation in vegetables grown in these soils. In this study, a greenhouse experiment was conducted to investigate the ability of As-hyperaccumulator P. vittata and organic amendments in reducing As uptake by lettuce (Lactuca sativa) from a soil contaminated from CCA-treated wood (63.9 mg kg -1 As). P. vittata was grown for 150 d in a CCA-contaminated soil amended with biochar, activated carbon or coffee grounds at 1%, followed by lettuce for another 55 d. After harvest, plant biomass and As concentrations in plant and soil were determined. The presence of P. vittata reduced As content in lettuce by 21% from 27.3 to 21.5 mg kg -1 while amendment further reduced As in lettuce by 5.6-18%, with activated C being most effective. Our data showed that both P. vittata and organic amendments were effective in reducing As concentration in lettuce. Though no health-based standard for As in vegetables exists in USA, care should be taken when growing lettuce in contaminated soils. Our data showed that application of organic amendments with P. vittata reduced As hazards in CCA-contaminated soils. Published by Elsevier Ltd.

Association analysis of bacterial leaf spot resistance and SNP markers derived from expressed sequence tags (ESTs) in lettuce (Lactuca sativa L.)

Science.gov (United States)

Bacterial leaf spot of lettuce, caused by Xanthomonas campestris pv. vitians, is a devastating disease of lettuce worldwide. Since there are no chemicals available for effective control of the disease, host-plant resistance is highly desirable to protect lettuce production. A total of 179 lettuce ge...

Influence of season growth, soils and irrigation water composition on the concentration of uranium in two lettuce (Lactuca sativa L.) varieties. Field experiments

Science.gov (United States)

Abreu, M. M.; Neves, O.; Marcelino, M.

2012-04-01

Former uranium mines areas are frequently the sources of environmental radionuclides problems even many years after the closure of mining operations. A concern for inhabitants from mining areas is the use of contaminated land or irrigation water for agriculture, and the potential transfer of metals from soils to vegetables, and to humans through the food chain. The main aim of this study was to compare the uranium concentration in lettuce (Lactuca sativa L. varieties Marady and Romana) grown in different seasons (autumn and summer) and exposed to high and low uranium concentrations both in irrigation water and agricultural soil. The content of uranium in irrigation water, soil (total and available fraction) and in lettuce leaf samples was analyzed in a certified laboratory. In the field experiments, two agricultural soils were divided into two plots (four replicates each); one of them was irrigated with uranium contaminated water (0.94 to 1.14 mg/L) and the other with uncontaminated water (< 0.02 mg/L). Irrigation with contaminated water together with highest soil uranium available concentration (10 to 13 mg/kg) had negative effects on both studied lettuce varieties, namely yield reduction (up to 53% and 87% in autumn and summer experiments, respectively) and increase of uranium leaf concentration (up to 1.4 and 7 fold in autumn and summer, respectively). Effect on lettuce yield was mainly due to the high soil salinity (1.01 to 6.31 mS/cm) as a consequence of high irrigation water electrical conductivity (up to 1.82 mS/cm) and low lettuce soil salinity tolerance (1 to 3 mS/cm). The highest lettuce uranium concentration (dry weight) observed was 2.13 and 5.37 mg/kg for Marady and Romana variety, respectively. The highest uranium lettuce concentration in Romana variety was also the effect of its growing in summer season when it was subject to greatest frequency and amount of water irrigation. The consumption by an adult of the lettuce that concentrate more uranium

Dye-sensitized solar cell using natural dyes extracted from spinach and ipomoea

Energy Technology Data Exchange (ETDEWEB)

Chang, H., E-mail: f10381@ntut.edu.t [Department of Mechanical Engineering, National Taipei University of Technology, No. 1. Sec. 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan (China); Wu, H.M. [Department of Materials Engineering, Tatung University, No. 40, Sec. 3, Jhongshan N. Rd. Jhongshan District, Taipei City 104, Taiwan (China); Chen, T.L. [Department of Industrial Design, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan (China); Huang, K.D. [Department of Vehicle Engineering, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan (China); Jwo, C.S. [Department of Energy and Air-Conditioning Refrigeration Engineering, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan (China); Lo, Y.J. [Department of Mechanical Engineering, National Taipei University of Technology, No. 1. Sec. 3, Chung-Hsiao E. Rd., Taipei 10608, Taiwan (China)

2010-04-16

This study used spinach extract, ipomoea leaf extract and their mixed extracts as the natural dyes for a dye-sensitized solar cell (DSSC). Spinach and ipomoea leaves were first placed separately in ethanol and the chlorophyll of these two kinds of plants was extracted to serve as the natural dyes for using in DSSCs. In addition, the self-developed nanofluid synthesis system prepared a TiO{sub 2} nanofluid with an average particle size of 50 nm. Electrophoresis deposition was performed to let the TiO{sub 2} deposit nanoparticles on the indium tin oxide (ITO) conductive glass, forming a TiO{sub 2} thin film with the thickness of 11.61 {mu}m. This TiO{sub 2} thin film underwent sintering at 450 {sup o}C to enhance the compactness of thin film. Finally, the sintered TiO{sub 2} thin film was immersed in the natural dye solutions extracted from spinach and ipomoea leaves, completing the production of the anode of DSSC. This study then further inspected the fill factor, photoelectric conversion efficiency and incident photon current efficiency of the encapsulated DSSC. According to the experimental results of current-voltage curve, the photoelectric conversion efficiency of the DSSCs prepared by natural dyes from ipomoea leaf extract is 0.318% under extraction temperature of 50 {sup o}C and pH value of extraction fluid at 1.0. This paper also investigated the influence of the temperature in the extraction process of this kind of natural dye and the influence of pH value of the dye solution on the UV-VIS patterns absorption spectra of the prepared natural dye solutions, and the influence of these two factors on the photoelectric conversion efficiency of DSSC.

Optimization of Agrobacterium-mediated transient expression of heterologous genes in spinach

DEFF Research Database (Denmark)

Cao, Dang Viet; Pamplona, Reniel S.; Kim, Jiwon

2017-01-01

The Agrobacterium-mediated transient assay is a relatively rapid technique and a promising approach for assessing the expression of a gene of interest. Despite the successful application of this transient expression system in several plant species, it is not well understood in spinach. In this st...

Impact of pigeon pea biochar on cadmium mobility in soil and transfer rate to leafy vegetable spinach.

Science.gov (United States)

Coumar, M Vassanda; Parihar, R S; Dwivedi, A K; Saha, J K; Rajendiran, S; Dotaniya, M L; Kundu, S

2016-01-01

Introduction of heavy metals in the environment by various anthropogenic activities has become a potential treat to life. Among the heavy metals, cadmium (Cd) shows relatively high soil mobility and has high phyto-mammalian toxicity. Integration of soil remediation and ecosystem services, such as carbon sequestration in soils through organic amendments, may provide an attractive land management option for contaminated sites. The application of biochar in agriculture has recently received much attention globally due to its associated multiple benefits, particularly, long-term carbon storage in soil. However, the application of biochar from softwood crop residue for heavy metal immobilization, as an alternative to direct field application, has not received much attention. Hence, a pot experiment was conducted to study the effect of pigeon pea biochar on cadmium mobility in a soil-plant system in cadmium-spiked sandy loam soil. The biochar was prepared from pigeon pea stalk through a slow pyrolysis method at 300 °C. The experiment was designed with three levels of Cd (0, 5, and 10 mg Cd kg(-1) soil) and three levels of biochar (0, 2.5, and 5 g kg(-1) soil) using spinach as a test crop. The results indicate that with increasing levels of applied cadmium at 5 and 10 mg kg(-1) soil, the dry matter yield (DMY) of spinach leaf decreased by 9.84 and 18.29 %, respectively. However, application of biochar (at 2.5 and 5 g kg(-1) soil) significantly increased the dry matter yield of spinach leaf by 5.07 and 15.02 %, respectively, and root by 14.0 and 24.0 %, respectively, over the control. Organic carbon content in the post-harvest soil increased to 34.9 and 60.5 % due to the application of biochar 2.5 and 5 g kg(-1) soil, respectively. Further, there was a reduction in the diethylene triamine pentaacetic acid (DTPA)-extractable cadmium in the soil and in transfer coefficient values (soil to plant), as well as its concentrations in spinach leaf and root, indicating that

Short-term alteration of nitrogen supply prior to harvest affects quality in hydroponic-cultivated spinach (Spinacia oleracea).

Science.gov (United States)

Lin, Xian Yong; Liu, Xiao Xia; Zhang, Ying Peng; Zhou, Yuan Qing; Hu, Yan; Chen, Qiu Hui; Zhang, Yong Song; Jin, Chong Wei

2014-03-30

Quality-associated problems, such as excessive in planta accumulation of oxalate, often arise in soillessly cultivated spinach (Spinacia oleracea). Maintaining a higher level of ammonium (NH₄⁺) compared to nitrate (NO₃⁻) during the growth period can effectively decrease the oxalate content in hydroponically cultivated vegetables. However, long-term exposure to high concentrations of NH₄⁺ induces toxicity in plants, and thus decreases the biomass production. Short-term application of NH₄⁺ before harvesting in soilless cultivation may provide an alternative strategy to decrease oxalate accumulation in spinach, and minimise the yield reduction caused by NH₄⁺ toxicity. The plants were pre-cultured in 8 mmol L⁻¹ NO₃⁻ nutrient solution. Next, 6 days before harvest, the plants were transferred to a nutrient solution containing 4 mmol L⁻¹ NO₃⁻ and 4 mmol L⁻¹ NH₄⁺. This new mix clearly reduced oxalate accumulation, increased levels of several antioxidant compounds, and enhanced antioxidant capacity in the edible parts of spinach plants, but it did not affect biomass production. However, when the 8 mmol L⁻¹ NO₃⁻ was shifted to either nitrogen-free, 4 mmol L⁻¹ NH₄⁺ or 8 mmol L⁻¹ NH₄⁺ treatments, although some of the quality indexes were improved, yields were significantly reduced. Short-term alteration of nitrogen supply prior to harvest significantly affects quality and biomass of spinach plants, and we strongly recommend to simultaneously use NO₃⁻ and NH₄⁺ in hydroponic cultivation, which improves vegetable quality without decreasing biomass production. © 2013 Society of Chemical Industry.

Effects of light irradiation control on the quality preservation of spinach [Spinacia oleracea] during postharvest storage

International Nuclear Information System (INIS)

Wang, H.; Saito, T.; Shiga, T.

2008-01-01

We examined the effects of the light irradiation on the quality changes of green leafy vegetables after harvest, and clarified the quality preservation method of spinach by the light irradiation with the modified atmosphere effects by the film packaging. Spinach packaged in the sealed film was irradiated at the photosynthetic photon flux density (PPFD) of 4 micromol/square m/s and 10 micromol/square m/s as almost same intensity level as light compensation point by the white fluorescent lamp, white light-emitting diode (LED) and the monochromatic LED's of wavelength at 470nm, 591nm, 626nm and 660nm respectively. The concentration of CO2 in the sealed film was proved to decrease according to the light irradiation regardless of the different wavelength of light, and this showed that the effects of present modified atmosphere packaging is lost by light irradiation. The increase of weight loss by light irradiation was controlled by the film packaging, and then the commercial value was excellently maintained. Light irradiation after harvest contributed to keeping high L-ascorbic acid contents of the spinach. However the light irradiation of different wavelength was not found to influence the change of L-ascorbic acid contents. (author)

Responses of different water spinach cultivars and their hybrid to Cd, Pb and Cd-Pb exposures.

Science.gov (United States)

Xin, Junliang; Huang, Baifei; Yang, Zhongyi; Yuan, Jiangang; Dai, Hongwen; Qiu, Qiu

2010-03-15

A pot experiment was conducted to investigate the stability of Cd and/or Pb accumulation in shoot of Cd and Pb pollution-safe cultivars (PSCs), the hereditary pattern of shoot Cd accumulation, and the transfer potentials of Cd and Pb in water spinach (Ipomoea aquatica Forsk.). A typical Cd-PSC, a typical non-Cd-PSC (Cd accumulative cultivar), a hybrid from the former two cultivars, and two typical Cd+Pb-PSCs were grown in seven soils with different concentrations of Cd and Pb. The results showed that concentrations of Cd and Pb in shoot of the PSCs were always lower than the non-PSC and the highest Cd and Pb transfer factors were also always observed in the non-PSC, indicating the stability of the PSCs in Cd and Pb accumulation. Shoot Cd concentration seemed to be controlled by high Cd dominant gene(s) and thus crossbreeding might not minimize Cd accumulation in water spinach. Interaction between Cd and Pb in soils affected the accumulations of the metals in shoot of water spinach. Under middle Cd and Pb treatments, the presence of higher Pb promoted the accumulation of Cd. However, under high Pb treatment, accumulations of Cd and Pb were both restricted. (c) 2009 Elsevier B.V. All rights reserved.

Influence of hydrogel on germination of lettuce and onion seed at different moisture levels

Directory of Open Access Journals (Sweden)

Kateřina Pazderů

2013-01-01

Full Text Available The influence of Agrisorb (water solution 1, 3, 5 g/l on lettuce and onion seed germination was tested in different moisture conditions (30 ml and 15 ml of water in germination box. Variants with reduced water level germinated much more slowly (MGT parameter than standard variants, though differences in total germination at the end of the test were insignificant. Treated variants of lettuce seeds showed a statistically significant increase in germination energy (GE on the first day (GE1, both water levels, but a significant decrease on the second day (columns GE2, 15 ml. Higher doses of Agrisorb slowed lettuce seed germination (GE2, 30 ml, dose 5 g significantly, similarly see GE2 (15 ml, doses 1, 3, 5 g. This slowdown was apparent for GE3 (both water amount as well. A similar but insignificant effect was evident for onions. There was an influence of cultivar and seed vigour on sensitivity to water stress. The hydrogel application influenced germination of lettuce and onion seeds. Treated lettuce seeds germinated faster than non-treated control in the beginning of germination process. This effect was not recorded in case of slowly germinated onion seed lots. Although influence of Agrisorb was positive in the beginning, higher doses of hydrogel reduced germination energy of treated seed lots (for example GE2, GE4 of both crops in comparison with non-treated control. Higher doses of hydrogel caused longer MGT of lettuce and onion as well.

Distribution and population development of Nasonovia ribisnigri (Homoptera: Aphididae) in iceberg lettuce.

Science.gov (United States)

Liu, Yong-Biao

2004-06-01

A field study was conducted to determine the distribution and development of aphid Nasonovia ribisnigri (Mosley) (Homoptera: Aphididae) populations in iceberg lettuce, Lactuca sativa L. 'Salinas'. Lettuce plants were transplanted and caged individually in the field and inoculated with apterous N. ribisnigri at 0, 1, 2, 3, and 4 wk after transplanting in spring and fall 2002. Plants were harvested 15-50 d after inoculations; numbers of alates and apterous N. ribisnigri were counted or estimated on each leaf for each plant. Inoculations during all 5 wk of plant development resulted in successful colonization of lettuce heads. Results indicated that head formation did not reduce the risk of colonization by N. ribisnigri to iceberg lettuce; plants were susceptible to colonization by N. ribisnigri throughout their development. For later inoculations, N. ribisnigri populations were relatively smaller, and aphids were found mostly within the heads. For earlier inoculations, N. ribisnigri populations were larger, and within-plant distributions shifted toward frame leaves. The shift of population distributions toward frame leaves correlated significantly with increases in N. ribisnigri population density. For most inoculations, more aphids were present on wrapper leaves than on other leaves. The proportion of alates did not vary significantly with population density. Population development of N ribisnigri also correlated significantly with heat unit accumulation. Yellow sticky cards were used to monitor alates in each cage. Catches of N. ribisnigri alates on yellow sticky cards were significantly correlated with total numbers of alates as well as with total population sizes on individual lettuce plants.

Heavy metals deposited in the culture of lettuce (Lactuca sativa L.) by the influence of vehicular traffic in Pernambuco, Brazil.

Science.gov (United States)

França, Fernanda C S S; Albuuerque, Adriana M A; Almeida, Amanda C; Silveira, Patrícia B; Filho, Crescêncio A; Hazin, Clovis A; Honorato, Eliane V

2017-01-15

Currently one of the main sources of atmospheric pollution identified in urban centers is derived from both industrial and motor vehicle emissions. These pollutants can be adsorbed to particulate matter which is present in the air or deposited in the soil and plants, eventually reaching the human food chain. In this context, the present study aimed to determine the concentration of metals such as Cu, Pb, Cd, Ni and Zn in two subspecies of Lactuca sativa L. and in the soil from were lettuce samples were collected. The results for the soil samples analyzed show a possible contamination by Pb with concentration values as high as 140mg.kg(-1), which are above the Brazilian standards defined by Resolution CONAMA 420/2009 (Brazilian Environmental Council). However, the values found in the lettuce itself reveal that it is still suitable for consumption. Copyright © 2016. Published by Elsevier Ltd.

Combined toxicity of microcystin-LR and copper on lettuce (Lactuca sativa L.).

Science.gov (United States)

Cao, Qing; Steinman, Alan D; Wan, Xiang; Xie, Liqiang

2018-05-10

Microcystins and copper commonly co-exist in the natural environment, but their combined toxicity remains unclear, especially in terrestrial plants. The present study investigated the toxicity effects of microcystin-LR (0, 5, 50, 500, 1000 μg L -1 ) and copper (0, 50, 500, 1000, 2000 μg L -1 ), both individually and in mixture, on the germination, growth and oxidative response of lettuce. The bioaccumulation of microcystin-LR and copper was also evaluated. Results showed that the decrease in lettuce germination induced by copper alone was not significantly different from that induced by the mixture, and the combined toxicity assessment showed a simple additive effect. Lettuce growth was not significantly reduced by microcystin-LR alone, whereas it was significantly reduced by copper alone and the mixture when copper concentration was higher than 500 μg L -1 . High concentrations of microcystin-LR (1000 μg L -1 ) and copper (≥50 μg L -1 ),as well as their mixture (≥50 + 500 μg L -1 ), induced oxidative stress in lettuce. A synergistic effect on the growth and antioxidative system of lettuce was observed when exposed to low concentrations of the mixture (≤50 + 500 μg L -1 ), whereas an antagonistic effect was observed at high concentrations (≥1000 + 2000 μg L -1 ). Moreover, the interaction of microcystin-LR and copper can increase their accumulation in lettuce. Our results suggest that the toxicity effects of microcystin-LR and copper are exacerbated when they co-exist in the natural environment at low concentrations, which not only negatively affects plant growth but also poses a potential risk to human health via the food chain. Copyright © 2018. Published by Elsevier Ltd.

Respiration rate and ethylene production of fresh cut lettuce as affected by cutting grade

Directory of Open Access Journals (Sweden)

J. MARTÍNEZ

2008-12-01

Full Text Available For designing optimal polymeric films for modified atmosphere packaging of whole heads as well as for minimally fresh processed (fresh-cut Iceberg lettuce ‘Coolguard’, the effect of several cutting grades on respiration rate (RR and ethylene production at 5ºC was studied. According to common industrial practices cutting grades less than 0.5 cm, between 0.5 and 1 cm, and 2 cm length were selected. Results from four experiments were compared to those obtained for whole heads in which a homogenous range of 6 to 8 ml CO2 kg-1 h-1 in RR was found. Compared to whole heads, in fresh-cut lettuce the RR was 2-fold higher. The lowest cutting grade showed the highest respiration rate, and no significant differences in RR among lettuce pieces of intermediate and the highest grades were found. No ethylene production was detected in whole heads, while in minimally processed lettuce pieces only traces were found. For avoiding risks of anaerobic respiration and excessive CO2 levels within packages containing fresh-cut lettuce pieces lower than 0.5 cm length, films with relatively high O2 permeability like standard polypropylene or low-density polyethylene must be selected.;

Impacts of EDTA on uptake and accumulation of Cu 2+ by spinach ...

African Journals Online (AJOL)

The effects of EDTA on Cu2+ uptake by spinach (spinacia oleracea L) seedlings replanted in hydroponic solutions in a greenhouse were investigated. Four week old seedlings were exposed to various doses of Cu2+ (0, 5, 10, 15, and 20mg/L) and constant concentration of EDTA (10mM). During the exposure, the plant ...

Characterization of an Olive Flounder Bone Gelatin-Zinc Oxide Nanocomposite Film and Evaluation of Its Potential Application in Spinach Packaging.

Science.gov (United States)

Beak, Songee; Kim, Hyeri; Song, Kyung Bin

2017-11-01

Olive flounder bone gelatin (OBG) was used for a film base material in this study. In addition, zinc oxide nanoparticles (ZnO) were incorporated into the OBG film to prepare a nanocomposite film and to impart antimicrobial activity to it. The tensile strength of the OBG film increased by 6.62 MPa, and water vapor permeability and water solubility decreased by 0.93 × 10 -9 g/m s Pa and 13.79%, respectively, by the addition of ZnO to the OBG film. In particular, the OBG-ZnO film exhibited antimicrobial activity against Listeria monocytogenes. To investigate the applicability of the OBG-ZnO packaging film, fresh spinach was wrapped in this film and stored for a week. The results indicated that the OBG-ZnO film showed antimicrobial activity against L. monocytogenes inoculated on spinach without affecting the quality of spinach, such as vitamin C content and color. Thus, the OBG-ZnO nanocomposite film can be applied as an efficient antimicrobial food packaging material. As a base material of edible films, gelatin was extracted from olive flounder bone, which is fish processing by-product. Olive flounder bone gelatin (OBG) nanocomposite films were prepared with zinc oxide nanoparticles (ZnO). For an application to antimicrobial packaging, spinach was wrapped with the OBG-ZnO nanocomposite film. © 2017 Institute of Food Technologists®.

Occurrence of Multidrug Resistant Extended Spectrum Beta-Lactamase-Producing Bacteria on Iceberg Lettuce Retailed for Human Consumption

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Natasha Bhutani

2015-01-01

Full Text Available Antibiotic resistance in bacteria is a global problem exacerbated by the dissemination of resistant bacteria via uncooked food, such as green leafy vegetables. New strains of bacteria are emerging on a daily basis with novel expanded antibiotic resistance profiles. In this pilot study, we examined the occurrence of antibiotic resistant bacteria against five classes of antibiotics on iceberg lettuce retailed in local convenience stores in Rochester, Michigan. In this study, 138 morphologically distinct bacterial colonies from 9 iceberg lettuce samples were randomly picked and tested for antibiotic resistance. Among these isolates, the vast majority (86% demonstrated resistance to cefotaxime, and among the resistant bacteria, the majority showed multiple drug resistance, particularly against cefotaxime, chloramphenicol, and tetracycline. Three bacterial isolates (2.17% out of 138 were extended spectrum beta-lactamase (ESBL producers. Two ESBL producers (T1 and T5 were identified as Klebsiella pneumoniae, an opportunistic pathogen with transferable sulfhydryl variable- (SHV- and TEM-type ESBLs, respectively. The DNA sequence analysis of the blaSHV detected in K. pneumoniae isolate T1 revealed 99% relatedness to blaSHV genes found in clinical isolates. This implies that iceberg lettuce is a potential reservoir of newly emerging and evolving antibiotic resistant bacteria and its consumption poses serious threat to human health.

Scientific rationale for cos lettuce growing technology Lactuca sativa var. longifolia L. in the Forest-Steppe of Ukraine

Directory of Open Access Journals (Sweden)

Н. В. Лещук

2014-04-01

Full Text Available Scientifically validated items of growing technology disclosed for cos lettuce marketable products in the conditions of Forest-Steppe of Ukraine. Impact of environmental factors onto growth and development of Lactuca sativa var. longifolia L. plants. Sowing terms established for the seed of cos lettuce at field-seeded growing. Development parameters are quoted for plant productivity indices and marketable product indices for cos lettuce of national and foreign breeding. According to VCU characteristics a  typical model has been designed for the cos lettuce indices of suitability for dissemination in Ukraine.

Purification, characterization and immunomodulatory activity of polysaccharides from stem lettuce.

Science.gov (United States)

Nie, Chenzhipeng; Zhu, Peilei; Ma, Shuping; Wang, Mingchun; Hu, Youdong

2018-05-15

Stem lettuce has a long history of cultivation in China and possesses high nutritional and medicinal value. In our previous studies, extraction optimization, characterization, and bioactivities of stem lettuce polysaccharides (SLP) were investigated. In this study, SLP were further separated into two purified polysaccharides, SLP-1 and SLP-2, by anion exchange chromatography followed by size exclusion chromatography. SLP-1, with a molecular weight of 90 KDa, was mainly composed of galacturonic acid, galactose and arabinose in a molar ratio of 17.6:41.7:33.9. SLP-2, with a molecular weight of 44 KDa, was mainly composed of mannose, galacturonic acid, galactose and arabinose in a molar ratio of 11.5:69.5:9.3:8.2. In addition, both purified polysaccharides contain sulphate radicals, have triple helical structures and can promote macrophage proliferation without cytotoxicity. SLP-2 was better able to stimulate phagocytic and nitric oxide production than SLP-1. The results suggest that polysaccharides from stem lettuce could be explored as immunomodulatory agents in the field of pharmaceuticals and functional foods. Copyright © 2018 Elsevier Ltd. All rights reserved.

Frequência de Lettuce big-vein associated virus e Mirafiori lettuce big-vein virus em Plantas de alface no Estado de São Paulo e transmissão através de extrato vegetal e solo Frequency of Lettuce big-vein associated virus and Mirafiori lettuce big-vein virus in symptomatic and assymptomatic lettuce plants and sap and soil transmission

Directory of Open Access Journals (Sweden)

Márcio Martinello Sanches

2007-12-01

Full Text Available A presença de sintomas de 'big vein' ou engrossamento das nervuras em alface e a associação do Lettuce big-vein associated virus (LBVaV e Mirafiori lettuce big-vein virus (MLBVV foram verificadas por RT-PCR utilizando-se oligonucleotídeos específicos para ambos os vírus. Foram coletadas 366 plantas sintomáticas nas regiões de Bauru, Campinas e Mogi das Cruzes no estado de São Paulo nos meses de junho e setembro de 2004 e abril e julho de 2005, e 18 plantas assintomáticas na região de Mogi das Cruzes no mês de dezembro de 2004. Infecção mista do LBVaV e MLBVV foi detectada em 76,2% das plantas sintomáticas, em 11,5% somente o MLBVV foi detectado e em 6,6% somente o LBVaV. Nas plantas assintomáticas coletadas em dezembro na região de Mogi das Cruzes, em áreas de alta incidência da doença durante o inverno, foi detectada a presença de MLBVV em 9 amostras e LBVaV em 7 amostras. Quatro dessas amostras apresentaram infecção mista, indicando que o desenvolvimento de sintomas depende de fatores abióticos, como temperatura. A inoculação via extrato vegetal a partir de plantas de alface com infecção mista pelo MLBVV e LBVaV foi realizada a 16°C/ 10°C (dia/noite e fotoperíodo de 11 horas, verificando-se que o MLBVV foi transmitido para Nicotiana tabacum TNN, N. rustica, N. occidentalis, Chenopodium quinoa e para as cultivares de alface Trocadero e White Boston, enquanto o LBVaV foi transmitido apenas para a alface White Boston. Entretanto, nenhuma destas plantas apresentou sintomas da doença, com exceção de C. quinoa que apresentou sintomas de lesões locais. Plantio em solo proveniente de áreas com histórico da doença de Mogi das Cruzes permitiu a transmissão do LBVaV para alface cv. White Boston e do MLBVV para alface cv. Trocadero e White Boston, embora apenas a cv. White Boston tenha apresentado sintomas da doença. Em conjunto, estes resultados demonstram a dificuldade de transmissão de ambos os vírus, mesmo em

Lettuce irrigated with contaminated water: Photosynthetic effects, antioxidative response and bioaccumulation of microcystin congeners.

Science.gov (United States)

Bittencourt-Oliveira, Maria do Carmo; Cordeiro-Araújo, Micheline Kézia; Chia, Mathias Ahii; Arruda-Neto, João Dias de Toledo; de Oliveira, Ênio Tiago; dos Santos, Flávio

2016-06-01

The use of microcystins (MCs) contaminated water to irrigate crop plants represents a human health risk due to their bioaccumulation potential. In addition, MCs cause oxidative stress and negatively influence photosynthetic activities in plants. The present study was aimed at investigating the effect of MCs on photosynthetic parameters and antioxidative response of lettuce. Furthermore, the bioaccumulation factor (BAF) of total MCs, MC-LR and MC-RR in the vegetable after irrigation with contaminated water was determined. Lettuce crops were irrigated for 15 days with water containing cyanobacterial crude extracts (Microcystis aeruginosa) with MC-LR (0.0, 0.5, 2.0, 5.0 and 10.0 µg L(-1)), MC-RR (0.0, 0.15, 0.5, 1.5 and 3.0 µg L(-1)) and total MCs (0.0, 0.65, 2.5, 6.5 and 13.0 µg L(-1)). Increased net photosynthetic rate, stomatal conductance, leaf tissue transpiration and intercellular CO2 concentration were recorded in lettuce exposed to different MCs concentrations. Antioxidant response showed that glutathione S-transferase activity was down-regulated in the presence of MCs. On the other hand, superoxide dismutase, catalase and peroxidase activities were upregulated with increasing MCs concentrations. The bioaccumulation factor (BAF) of total MCs and MC-LR was highest at 6.50 and 5.00 µg L(-1), respectively, while for MC-RR, the highest BAF was recorded at 1.50 µg L(-1) concentration. The amount of total MCs, MC-LR and MC-RR bioacumulated in lettuce was highest at the highest exposure concentrations. However, at the lowest exposure concentration, there were no detectable levels of MC-LR, MC-RR and total MCs in lettuce. Thus, the bioaccumulation of MCs in lettuce varies according to the exposure concentration. In addition, the extent of physiological response of lettuce to the toxins relies on exposure concentrations. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of proteome response to saline and zinc stress in lettuce

OpenAIRE

Lucini, Luigi; Bernardo, Letizia

2015-01-01

Zinc salts occurring in soils can exert an osmotic stress toward plants. However, being zinc a heavy metal, some more specific effects on plant metabolisms can be forecast. In this work, lettuce has been used as a model to investigate salt and zinc stresses at proteome level through a shotgun tandem MS proteomic approach. The effect of zinc stress in lettuce, in comparison with NaCl stress, was evaluated to dissect between osmotic/oxidative stress related effects, from those changes specifica...

TRACKING CHANGES IN CHLOROPHYLL AND CAROTENOIDS IN THE PRODUCTION PROCESS OF FROZEN SPINACH PURÉE

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Andrea Mendelová

2014-02-01

Full Text Available Spinach is in the professional and general public considered highly nutritious vegetable with many beneficial effects on human health. It is a rich source of antioxidant active substances, especially chlorophyll, carotenoids, flavonoids and minerals especially zinc and copper. This work studies the changes of chlorophyll and carotenoids that occur after mass production technology of freezing at -37 °C. Before freezing was used blanching operation. In this work we used a variety Boeing, Boa, Beaver, Hudson and Chica. The highest content of all monitored parameters are found in fresh leaves of sampled Hudson. We found that within the processing decreases chlorophyll in 16.6%, 13.8% of chlorophyll b and carotenoids of 6.15%. This decrease was in all cases statistically significant.

Cold Plasma-activated hydrogen peroxide aerosol inactivates Escherichia coli 0157:H7, Salmonella Typhimurium, and Listeria innocua and maintains quality of grape tomato, spinach and cantaloupe

Science.gov (United States)

The purpose of this study was to investigate the efficacy of aerosolized hydrogen peroxide in inactivating bacteria and maintaining quality of grape tomato, baby spinach leaves and cantaloupe. Stem scar and smooth surfaces of tomatoes, spinach leaves, and cantaloupe rinds, inoculated with Escherich...

Sequential determination of fat- and water-soluble vitamins in green leafy vegetables during storage.

Science.gov (United States)

Santos, J; Mendiola, J A; Oliveira, M B P P; Ibáñez, E; Herrero, M

2012-10-26

The simultaneous analysis of fat- and water-soluble vitamins from foods is a difficult task considering the wide range of chemical structures involved. In this work, a new procedure based on a sequential extraction and analysis of both types of vitamins is presented. The procedure couples several simple extraction steps to LC-MS/MS and LC-DAD in order to quantify the free vitamins contents in fresh-cut vegetables before and after a 10-days storage period. The developed method allows the correct quantification of vitamins C, B(1), B(2), B(3), B(5), B(6), B(9), E and provitamin A in ready-to-eat green leafy vegetable products including green lettuce, ruby red lettuce, watercress, swiss chard, lamb's lettuce, spearmint, spinach, wild rocket, pea leaves, mizuna, garden cress and red mustard. Using this optimized methodology, low LOQs were attained for the analyzed vitamins in less than 100 min, including extraction and vitamin analysis using 2 optimized procedures; good repeatability and linearity was achieved for all vitamins studied, while recoveries ranged from 83% to 105%. The most abundant free vitamins found in leafy vegetable products were vitamin C, provitamin A and vitamin E. The richest sample on vitamin C and provitamin A was pea leaves (154 mg/g fresh weight and 14.4 mg/100g fresh weight, respectively), whereas lamb's lettuce was the vegetable with the highest content on vitamin E (3.1 mg/100 g fresh weight). Generally, some losses of vitamins were detected after storage, although the behavior of each vitamin varied strongly among samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Transcriptome analysis and anthocyanin-related genes in red leaf lettuce.

Science.gov (United States)

Zhang, Y Z; Xu, S Z; Cheng, Y W; Ya, H Y; Han, J M

2016-01-29

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 clean data were obtained and de novo assembled into 83,333 unigenes with an N50 of 1067. After annotation against public databases, 51,850 unigene sequences were identified, among which 46,087 were annotated in the NCBI non-redundant protein database, and 41,752 were annotated in the Swiss-Prot database. A total of 9125 unigenes were mapped into 163 pathways using the Kyoto Encyclopedia of Genes and Genomes database. Thirty-four structural genes were found to cover the main steps of the anthocyanin pathway, including chalcone synthase, chalcone isomerase, flavanone 3-hydroxylase, flavonoid 3'-hydroxylase, flavonoid 3',5'-hydroxylase, dihydroflavonol 4-reductase, and anthocyanidin synthase. Seven MYB, three bHLH, and two WD40 genes, considered anthocyanin regulatory genes, were also identified. In addition, 3607 simple sequence repeat (SSR) markers were identified from 2916 unigenes. This research uncovered the transcriptomic characteristics of red leaf lettuce seedlings and mature plants. The identified candidate genes related to anthocyanin biosynthesis and the detected SSRs provide useful tools for future molecular breeding studies.

Improvement of the growth and yield of lettuce plants by elf sinusoidal non-uniform magnetic fields

International Nuclear Information System (INIS)

Souzal, A. De; Gonzalez, L.M.; Sueirol, L.; Peralta, O.; Liceal, L.; Porras, E.; Gilart, F.

2008-01-01

Influence of pre-sowing magnetic treatments on plant growth and final yield of lettuce (cv. Black Seeded Simpson) were studied under organoponic conditions. Lettuce seeds were exposed to full-wave rectified sinusoidal non-uniform magnetic fields (MFs) induced by an electromagnet at 120 mT(rms) for 3 min, 160 mT(rms) for 1 min and to 160 mT (rms) for 5 min. Non-treated seeds were considered as controls. Plants were grown in experimental stonemasons (25.2 m2) of an organoponic and cultivated according to standard agricultural practices. During nursery and vegetative growth stages, samples were collected at regular intervals for seedling growth assessment and growth rate analyses. At physiological maturity, the plants were harvested from each stonemason and the final yield and yield parameters were determined. In the nursery stage, the magnetic treatments induced a significant increase of root length and shoot height in plants derived from magnetically-treated seeds. In the vegetative stage, the relative growth rates of plants derived from magnetically-exposed seeds were greater than those shown by the control plants. At maturity stage, all magnetic treatments increased significantly (p<0.05) the plant height, the leaf area per plant, the final yield per area and the fresh mass per plant in comparison with the controls. Pre-sowing magnetic treatments would enhance the growth and final yield of lettuce crop

Sewage sludge amendment and inoculation with plant-parasitic nematodes do not facilitate the internalization of Salmonella Typhimurium LT2 in lettuce plants.

Science.gov (United States)

Fornefeld, Eva; Baklawa, Mohamed; Hallmann, Johannes; Schikora, Adam; Smalla, Kornelia

2018-05-01

Contamination of fruits and vegetables with Salmonella is a serious threat to human health. In order to prevent possible contaminations of fresh produce it is necessary to identify the contributing ecological factors. In this study we investigated whether the addition of sewage sludge or the presence of plant-parasitic nematodes foster the internalization of Salmonella enterica serovar Typhimurium LT2 into lettuce plants, posing a potential threat for human health. Greenhouse experiments were conducted to investigate whether the amendment of sewage sludge to soil or the presence of plant-parasitic nematodes Meloidogyne hapla or Pratylenchus crenatus promote the internalization of S. Typhimurium LT2 from soil into the edible part of lettuce plants. Unexpectedly, numbers of cultivable S. Typhimurium LT2 decreased faster in soil with sewage sludge than in control soil but not in root samples. Denaturing gradient gel electrophoresis analysis revealed shifts of the soil bacterial communities in response to sewage sludge amendment and time. Infection and proliferation of nematodes inside plant roots were observed but did not influence the number of cultivable S. Typhimurium LT2 in the root samples or in soil. S. Typhimurium LT2 was not detected in the leaf samples 21 and 49 days after inoculation. The results indicate that addition of sewage sludge, M. hapla or P. crenatus to soil inoculated with S. Typhimurium LT2 did not result in an improved survival in soil or internalization of lettuce plants. Copyright © 2017. Published by Elsevier Ltd.

Practical use of the fertigation control based on cumulative solar radiation to decrease the nitrate concentration in spinach [Spinacia oleracea] grown in the greenhouse

International Nuclear Information System (INIS)

Shinohara, Y.; Tsukagoshi, S.; Hayashi, N.; Maruo, T.; Hohjo, M.

2007-01-01

Spinach plants (Spinacia oleracea L.) were grown in a greenhouse using fertigation based on cumulative solar radiation, and effects on plant growth, nitrate concentration in the leaves, and nitrate utilization/application ratio were studied. The relation of water and NO3-N absorption to cumulative solar radiation was initially determined in hydroponically grown spinach, then the stepwise fertigation program was set to 1.0, 1.2 and 1.4 times the standard quantity. With 1.2 fertigation treatment, plant growth and leaf color did not differ from those of plants cultivated by conventional soil culture. Total nitrate supplied to the soil under fertigation treatment were about half of that at soil culture. The nitrate utilization/application ratio was increased from 44% in soil culture to 82% under fertigation treatment. The nitrate concentration in spinach leaves under fertigation treatments tended to be lower compared to those under soil culture. In addition, the production of spinach with lower nitrate and without effects on growth seemed to be feasible by the withdrawal of NO3-N in the drip solution for several days before harvest

Development of air conditioning system and labor saving technology for efficient hydroponic cultivation; Konoritsuna suiko saibai no tame no kucho to shoryokuka gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Okano, T.; Terazoe, H.; Shoji, K. [Central Research Institute of Electric Power Industry, Tokyo (Japan); Yonezawa, K.; Otani, F. [Chugoku Electric Power Co. Inc., Hiroshima (Japan); Sekiyama, T.; Kosakai, K.; Sato, H.

1997-06-01

Equipment which made experiments on air conditioning and hydroponic cultivation possible was set up at the technical research center of the Chugoku Electric Power Co., to study an air conditioning system using night power and energy saving technology for the cultivation. Vegetables suitable to the cultivation were selected. For air conditioning, adopted was a water heat storage air conditioning system using night power. The space between the shade curtain and the greenhouse roof was ventilated to prevent increase in cooling load caused by rise in curtain temperature. Moreover, the cultivation equipment was covered with transparent vinyl film to cool the inside of the equipment. The hydroponic cultivation equipment was trially manufactured which makes the continued production by one worker possible. The cultivation of spinach, leaf lettuce and chingensai throughout the year became possible. The yield of chingensai reached the target, but those of spinach and leaf lettuce were approximately 70% of the targets. Vegetables to be produced in the air-conditioned greenhouse by hydroponic cultivation are thought to be those that can have added values such non-pesticides and ingredients, young plants which were increased by cutting or tissue culturing, etc. 5 refs., 19 figs., 8 tabs.

Proteomic analysis of lettuce seed germination and thermoinhibition by sampling of individual seeds at germination and removal of storage proteins by polyethylene glycol fractionation

DEFF Research Database (Denmark)

Wang, Wei-Qing; Song, Bin-Yan; Deng, Zhi-Jun

2015-01-01

the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination...

Fluorescence hyperspectral imaging technique for foreign substance detection on fresh-cut lettuce.

Science.gov (United States)

Mo, Changyeun; Kim, Giyoung; Kim, Moon S; Lim, Jongguk; Cho, Hyunjeong; Barnaby, Jinyoung Yang; Cho, Byoung-Kwan

2017-09-01

Non-destructive methods based on fluorescence hyperspectral imaging (HSI) techniques were developed to detect worms on fresh-cut lettuce. The optimal wavebands for detecting the worms were investigated using the one-way ANOVA and correlation analyses. The worm detection imaging algorithms, RSI-I (492-626)/492 , provided a prediction accuracy of 99.0%. The fluorescence HSI techniques indicated that the spectral images with a pixel size of 1 × 1 mm had the best classification accuracy for worms. The overall results demonstrate that fluorescence HSI techniques have the potential to detect worms on fresh-cut lettuce. In the future, we will focus on developing a multi-spectral imaging system to detect foreign substances such as worms, slugs and earthworms on fresh-cut lettuce. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Isolation, molecular identification and quinolone-susceptibility testing of Arcobacter spp. isolated from fresh vegetables in Spain.

Science.gov (United States)

González, Ana; Bayas Morejón, Isidro Favián; Ferrús, María Antonia

2017-08-01

Some species of the Arcobacter genus are considered emerging foodborne and waterborne enteropathogens. However, the presence of Arcobacter spp. in vegetables very little is known, because most studies have focused on foods of animal origin. On the other hand, quinolones are considered as first-line drugs for the treatment of infection by campylobacteria in human patients, but few data are currently available about the resistance levels to these antibiotics among Arcobacter species. Therefore, the aim of this study was to investigate the presence and diversity of arcobacters isolated from fresh vegetables such as lettuces, spinaches, chards and cabbages. Resistance to quinolones of the isolates was also investigated. One hundred fresh vegetables samples purchased from seven local retail markets in Valencia (Spain) during eight months were analysed. The study included 41 lettuces, 21 spinaches, 34 chards and 4 cabbages. Samples were analysed by culture and by molecular methods before and after enrichment. By culture, 17 out of 100 analysed samples were Arcobacter positive and twenty-five isolates were obtained from them. Direct detection by PCR was low, with only 4% Arcobacter spp. positive samples. This percentage increased considerably, up 20%, after 48 h enrichment. By polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), 17 out of the 25 isolates were identified as A. butzleri and 8 as A. cryaerophilus. Only two A. butzleri isolates showed resistance to levofloxacin and ciprofloxacin. The sequencing of a fragment of the QRDR region of the gyrA gene from the quinolones-resistant isolates revealed the presence of a mutation in position 254 of this gene (C-T transition). This study is the first report about the presence of pathogenic species of Arcobacter spp. in chards and cabbages and confirms that fresh vegetables can act as transmission vehicle to humans. Moreover, the presence of A. butzleri quinolone resistant in vegetables could

Inhibition of photosynthesis in isolated spinach chloroplasts by inorganic phosphate or inorganic pyrophosphatase in the presence of pyrophosphate and magnesium ions

Energy Technology Data Exchange (ETDEWEB)

Levine, G; Bassham, J A

1974-01-01

Inhibition of photosynthesis in isolated spinach chloroplasts by P/sub i/ is decreased by the presence of PP/sub i/ and increased with increasing Mg/sup 2 +/ concentration. Previously reported regulation of this photosynthesis by protein factors from spinach leaves appears to be due mostly to pyrophosphate phosphohydrolase (EC 3.6.1.1) activity which converts PP/sub i/ to P/sub i/ and to the effects of PP/sub i/ and Mg/sup 2 +/ on this pyrophosphatase activity.

Acidovorax valerianellae sp. nov., a novel pathogen of lamb's lettuce [Valerianella locusta (L.) Laterr].

Science.gov (United States)

Gardan, Louis; Stead, David E; Dauga, Catherine; Gillis, Moniek

2003-05-01

Bacterial spot disease of lamb's lettuce [Valerianella locusta (L.) Laterr.] was first observed in fields in 1991. This new bacterial disease is localized in western France in high-technology field production of lamb's lettuce for the preparation of ready-to-use salad. Nineteen strains isolated in 1992 and 1993 from typical black leaf spots of naturally infected lamb's lettuce were characterized and compared with reference strains of Acidovorax and Delftia. The pathogenicity of the 19 strains was confirmed by artificial inoculation. Biochemical and physiological tests, fatty acid profiles, DNA-DNA hybridization and other nucleic acid-based tests were performed. A numerical taxonomic analysis of the 19 lamb's lettuce strains showed a single homogeneous phenon closely related to previously described phytopathogenic taxa of the genus Acidovorax. DNA-DNA hybridization studies showed that the lamb's lettuce strains were 91-100% related to a representative strain, strain CFBP 4730(T), and constituted a discrete DNA hybridization group, indicating that they belong to the same novel species. Results from DNA-rRNA hybridization, 16S rRNA sequence analysis and fatty acid analysis studies confirmed that this novel species belongs to the beta-subclass of the Proteobacteria and, more specifically, to the family Comamonadaceae and the genus Acidovorax. The name Acidovorax valerianellae sp. nov. is proposed for this novel taxon of phytopathogenic bacteria. The type strain is strain CFBP 4730(T) (= NCPPB 4283(T)).

Colonization of lettuce rhizosphere and roots by tagged Streptomyces.

Science.gov (United States)

Bonaldi, Maria; Chen, Xiaoyulong; Kunova, Andrea; Pizzatti, Cristina; Saracchi, Marco; Cortesi, Paolo

2015-01-01

Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots, and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic.

Diversity and evolutionary history of lettuce necrotic yellows virus in Australia and New Zealand.

Science.gov (United States)

Higgins, Colleen M; Chang, Wee-Leong; Khan, Subuhi; Tang, Joe; Elliott, Carol; Dietzgen, Ralf G

2016-02-01

Lettuce necrotic yellows virus (LNYV) is the type member of the genus Cytorhabdovirus, family Rhabdoviridae, and causes a severe disease of lettuce (Lactuca sativa L.). This virus has been described as endemic to Australia and New Zealand, with sporadic reports of a similar virus in Europe. Genetic variability studies of plant-infecting rhabdoviruses are scarce. We have extended a previous study on the variability of the LNYV nucleocapsid gene, comparing sequences from isolates sampled from both Australia and New Zealand, as well as analysing symptom expression on Nicotiana glutinosa. Phylogenetic and BEAST analyses confirm separation of LNYV isolates into two subgroups (I and II) and suggest that subgroup I is slightly older than subgroup II. No correlation was observed between isolate subgroup and disease symptoms on N. glutinosa. The origin of LNYV remains unclear; LNYV may have moved between native and weed hosts within Australia or New Zealand before infecting lettuce or may have appeared as a result of at least two incursions, with the first coinciding with the beginning of European agriculture in the region. The apparent extinction of subgroup I in Australia may have been due to less-efficient dispersal than that which has occurred for subgroup II - possibly a consequence of suboptimal interactions with plant and/or insect hosts. Introduction of subgroup II to New Zealand appears to be more recent. More-detailed epidemiological studies using molecular tools are needed to fully understand how LNYV interacts with its hosts and to determine where the virus originated.

Mechanism of artemisinin phytotoxicity action: induction of reactive oxygen species and cell death in lettuce seedlings.

Science.gov (United States)

Yan, Zhi-Qiang; Wang, Dan-Dan; Ding, Lan; Cui, Hai-Yan; Jin, Hui; Yang, Xiao-Yan; Yang, Jian-She; Qin, Bo

2015-03-01

Artemisinin has been recognized as an allelochemical that inhibits growth of several plant species. However, its mode of action is not well clarified. In this study, the mechanism of artemisinin phytotoxicity on lettuce seedlings was investigated. Root and shoot elongation of lettuce seedlings were inhibited by artemisinin in a concentration-dependent manner. The compound effectively arrested cell division and caused loss of cell viability in root tips of lettuce. Overproduction of reactive oxygen species (ROS) was induced by artemisinin. Lipid peroxidation, proline overproduction and reduction of chlorophyll content in lettuce seedlings were found after treatments. These results suggested that artemisinin could induce ROS overproduction, which caused membrane lipids peroxidation and cell death, and impacted mitosis and physiological processes, resulting in growth inhibition of receptor plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

76 FR 50992 - Notice of Availability of a Pest Risk Analysis for the Importation of Shredded Lettuce From Egypt

Science.gov (United States)

2011-08-17

...] Notice of Availability of a Pest Risk Analysis for the Importation of Shredded Lettuce From Egypt AGENCY... into the continental United States of fresh shredded lettuce from Egypt. Based on this analysis, we... fresh shredded lettuce from Egypt. We are making the pest risk analysis available to the public for...

LCM-seq reveals the crucial role of LsSOC1 in heat-promoted bolting of lettuce (Lactuca sativa L.).

Science.gov (United States)

Chen, Zijing; Zhao, Wensheng; Ge, Danfeng; Han, Yingyan; Ning, Kang; Luo, Chen; Wang, Shenglin; Liu, Renyi; Zhang, Xiaolan; Wang, Qian

2018-05-17

Lettuce (Lactuca sativa L.) is one of the most economically important vegetables. The floral transition in lettuce is accelerated under high temperatures, which can significantly decrease yields. However, the molecular mechanism underlying the floral tranition in lettuce is poorly known. Using laser capture microdissection coupled with RNA sequencing, we isolated shoot apical meristem cells from the bolting-sensitive lettuce line S39 at four critical stages of development. Subsequently, we screened specifically for the flowering-related gene LsSOC1 during the floral transition through comparative transcriptomic analysis. Molecular biology, developmental biology, and biochemical tools were combined to investigate the biological function of LsSOC1 in lettuce. LsSOC1 knockdown by RNA interference resulted in a significant delay in the timing of bolting and insensitivity to high temperature, which indicated that LsSOC1 functions as an activator during heat-promoted bolting in lettuce. We determined that two heat-shock transcription factors, HsfA1e and HsfA4c, bound to the promoter of LsSOC1 to confirm that LsSOC1 played an important role in heat-promoted bolting. This study indicates that LsSOC1 plays a crucial role in the heat-promoted bolting process in lettuce. Further investigation of LsSOC1 may be useful for clarification of the bolting mechanism in lettuce. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Persistence and internalization of Salmonella on/in organic spinach sprout: exploring the contamination route

Science.gov (United States)

Purpose: The effects of contamination route, including seed and water, on the persistence and internalization of Salmonella in organic spinach cultivars- Lazio, Space, Emilia and Waitiki were studied. Methods: Seeds (1g) were contaminated with S. Newport using 10 ml of S. Newport-water suspension ov...

Post-harvest decay in fresh-cut lettuce

Science.gov (United States)

Shelf-life of fresh-cut lettuce was assessed in two mapping population (Salinas 88 x La Brillante, and Pavane x Parade. The most significant QTL was detected in both populations on linkage group 4. This QTL was detected in seven experiments grown in different environments. Molecular markers are bein...

Low-dose irradiation of cut iceberg lettuce in modified atmosphere packaging

International Nuclear Information System (INIS)

Hagenmaier, R.D.; Baker, R.A.

1997-01-01

Irradiation at a mean dosage of 0.19 kGy of commercially prepared fresh-cut lettuce resulted in a product that had, 8 days after irradiation, microbial population of 290 cfu/g and yeast population of 60 cfu/g, compared with values of 220 000 and 1 400 cfu/g, respectively, for the nonirradiated control. Irradiation also caused moderate changes in respiration rate and headspace gas concentrations. It appears feasible to combine chlorination with irradiation at 0.15-0.5 kGy to produce fresh-cut, chopped lettuce with reduced microbial population

Characteristic of fermented spinach (Amaranthus spp.) polyphenol by kombucha culture for antioxidant compound

Science.gov (United States)

Aspiyanto, Susilowati, Agustine; Iskandar, Jeti M.; Melanie, Hakiki; Maryati, Yati; Lotulung, Puspa D.

2017-01-01

Fermentation on spinach (Amaranthus sp.) vegetable by kombucha culture as an effort to get poliphenol as antioxidant compound had been done. Purification of fermented spinach extract suspension was carried out through microfiltration (MF) membrane (pore size 0.15 µm) fitted in dead-end Stirred Ultrafiltration Cell (SUFC) mode at fixed condition (stirrer rotation 400 rpm, room temperature, pressure 40 psia). Result of the experimental activity showed that long fermentation time increased total acids, total polyphenol and Total Plate Count (TPC), and decreased total solids and reducing sugar in biomass. The optimal fermentation time was reached for 2 weeks with total polyphenol recovery increasing of 92.76 % from before and after fermentation. On this optimal fermentation time, biomass had identified galic acid with relative intensity of 8 %, while as polyphenol monomer was resulted 5 kinds of polyphenol compounds with total intensity 27.97 % and molecular weight (MW) 191.1736, 193.1871 and 194.2170 at T2.5, T2.86 and T3.86. Long fermentation time increased functional properties of polyphenol as antioxidant.

Research on lettuce growth technology onboard Chinese Tiangong II Spacelab

Science.gov (United States)

Shen, Yunze; Guo, Shuangsheng; Zhao, Pisheng; Wang, Longji; Wang, Xiaoxia; Li, Jian; Bian, Qiang

2018-03-01

Lettuce was grown in a space vegetable cultivation facility onboard the Tiangong Ⅱ Spacelab during October 18 to November 15, 2016, in order to testify the key cultivating technology in CELSS under spaceflight microgravity condition. Potable water was used for irrigation of rooting substrate and the SRF (slowly released fertilizer) offered mineral nutrition for plant growth. Water content and electric conductivity in rooting substrate were measured based on FDR(frequency domain reflectometry) principle applied first in spaceflight. Lettuce germinated with comparative growth vigor as the ground control, showing that the plants appeared to be not stressed by the spaceflight environment. Under microgravity, lettuce grew taller and showed deeper green color than the ground control. In addition, the phototropism of the on-orbit plants was more remarkable. The nearly 30-d spaceflight test verified the seed fixation technology and water& nutrition management technology, which manifests the feasibility of FDR being used for measuring moisture content and electric conductivity in rooting zone under microgravity. Furthermore, the edibility of the space-grown vegetable was proved, providing theoretical support for astronaut to consume the space vegetable in future manned spaceflight.

An Ultra-High-Density, Transcript-Based, Genetic Map of Lettuce

Science.gov (United States)

Truco, Maria José; Ashrafi, Hamid; Kozik, Alexander; van Leeuwen, Hans; Bowers, John; Wo, Sebastian Reyes Chin; Stoffel, Kevin; Xu, Huaqin; Hill, Theresa; Van Deynze, Allen; Michelmore, Richard W.

2013-01-01

We have generated an ultra-high-density genetic map for lettuce, an economically important member of the Compositae, consisting of 12,842 unigenes (13,943 markers) mapped in 3696 genetic bins distributed over nine chromosomal linkage groups. Genomic DNA was hybridized to a custom Affymetrix oligonucleotide array containing 6.4 million features representing 35,628 unigenes of Lactuca spp. Segregation of single-position polymorphisms was analyzed using 213 F7:8 recombinant inbred lines that had been generated by crossing cultivated Lactuca sativa cv. Salinas and L. serriola acc. US96UC23, the wild progenitor species of L. sativa. The high level of replication of each allele in the recombinant inbred lines was exploited to identify single-position polymorphisms that were assigned to parental haplotypes. Marker information has been made available using GBrowse to facilitate access to the map. This map has been anchored to the previously published integrated map of lettuce providing candidate genes for multiple phenotypes. The high density of markers achieved in this ultradense map allowed syntenic studies between lettuce and Vitis vinifera as well as other plant species. PMID:23550116

An Ultra-High-Density, Transcript-Based, Genetic Map of Lettuce.

Science.gov (United States)

Truco, Maria José; Ashrafi, Hamid; Kozik, Alexander; van Leeuwen, Hans; Bowers, John; Wo, Sebastian Reyes Chin; Stoffel, Kevin; Xu, Huaqin; Hill, Theresa; Van Deynze, Allen; Michelmore, Richard W

2013-04-09

We have generated an ultra-high-density genetic map for lettuce, an economically important member of the Compositae, consisting of 12,842 unigenes (13,943 markers) mapped in 3696 genetic bins distributed over nine chromosomal linkage groups. Genomic DNA was hybridized to a custom Affymetrix oligonucleotide array containing 6.4 million features representing 35,628 unigenes of Lactuca spp. Segregation of single-position polymorphisms was analyzed using 213 F 7:8 recombinant inbred lines that had been generated by crossing cultivated Lactuca sativa cv. Salinas and L. serriola acc. US96UC23, the wild progenitor species of L. sativa The high level of replication of each allele in the recombinant inbred lines was exploited to identify single-position polymorphisms that were assigned to parental haplotypes. Marker information has been made available using GBrowse to facilitate access to the map. This map has been anchored to the previously published integrated map of lettuce providing candidate genes for multiple phenotypes. The high density of markers achieved in this ultradense map allowed syntenic studies between lettuce and Vitis vinifera as well as other plant species. Copyright © 2013 Truco et al.

Cadmium determination in lettuce grown in contaminated soil by INAAA and GFAAS

Energy Technology Data Exchange (ETDEWEB)

Armelin, Maria Jose A.; Maihara, Vera A.; Saiki, Mitiko, E-mail: marmelin@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Trevizam, Anderson R.; Silva, Maria Ligia S. [Universidade Estadual do Centro Oeste (UNICENTRO), Guarapuava, PR (Brazil); Muraoka, Takashi, E-mail: muraoka@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

2011-07-01

Although Cd is not essential for the mammalian organism, it follows in body the same pathways of essential elements such as zinc and copper. There is evidence that the Cd induced reduction of Ca absorption, may lead to the development of osteoporosis. Anthropogenic activities associated with industrial activities, mining and use of fertilizers, limestone pesticides in agriculture are the main sources of Cd enrichment in soils. Due to the possibility that Cd being absorbed by plants and through them to reach the food chain, interest has increased in regard to developing techniques for remediation of contaminated sites. The addition of substances capable of immobilizing the toxic elements from the soil is a procedure that has been used for remediation of contaminated sites. The function of these substances is to reduce the mobility and bioavailability of potentially toxic elements in the soil. In this study, five doses of phosphorus as triple phosphorus were used in a number of lettuce plants grown in contaminated soil. The concentration of Cd present in lettuce leaves treated with phosphate was compared with the Cd absorbed by the control plant leaves. Instrumental Neutron Activation Analysis (INAA) and Graphite-Furnace Absorption Atomic Spectrometry (GFAAS) were the analytical methods used to determine Cd contents in lettuce leaves. The objective was to evaluate the performance of the employed analytical methods: INAA and GFAAS in the assessment of the efficiency of phosphorus treatments to reduce the Cd concentrations in leaves of lettuce. Results obtained indicated that both analytical methods were efficient to discriminate the response of Cd concentration in lettuce as a function of soil treatment with phosphorus. Although INAA has shown a positive performance in this study, GFAAS seemed more appropriate because its sensitivity was much higher than that obtained by INAA, in the experimental conditions. (author)

Cadmium determination in lettuce grown in contaminated soil by INAAA and GFAAS

International Nuclear Information System (INIS)

Armelin, Maria Jose A.; Maihara, Vera A.; Saiki, Mitiko; Trevizam, Anderson R.; Silva, Maria Ligia S.; Muraoka, Takashi

2011-01-01

Although Cd is not essential for the mammalian organism, it follows in body the same pathways of essential elements such as zinc and copper. There is evidence that the Cd induced reduction of Ca absorption, may lead to the development of osteoporosis. Anthropogenic activities associated with industrial activities, mining and use of fertilizers, limestone pesticides in agriculture are the main sources of Cd enrichment in soils. Due to the possibility that Cd being absorbed by plants and through them to reach the food chain, interest has increased in regard to developing techniques for remediation of contaminated sites. The addition of substances capable of immobilizing the toxic elements from the soil is a procedure that has been used for remediation of contaminated sites. The function of these substances is to reduce the mobility and bioavailability of potentially toxic elements in the soil. In this study, five doses of phosphorus as triple phosphorus were used in a number of lettuce plants grown in contaminated soil. The concentration of Cd present in lettuce leaves treated with phosphate was compared with the Cd absorbed by the control plant leaves. Instrumental Neutron Activation Analysis (INAA) and Graphite-Furnace Absorption Atomic Spectrometry (GFAAS) were the analytical methods used to determine Cd contents in lettuce leaves. The objective was to evaluate the performance of the employed analytical methods: INAA and GFAAS in the assessment of the efficiency of phosphorus treatments to reduce the Cd concentrations in leaves of lettuce. Results obtained indicated that both analytical methods were efficient to discriminate the response of Cd concentration in lettuce as a function of soil treatment with phosphorus. Although INAA has shown a positive performance in this study, GFAAS seemed more appropriate because its sensitivity was much higher than that obtained by INAA, in the experimental conditions. (author)

Effect of various conditions on inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in fresh-cut lettuce using ultraviolet radiation.

Science.gov (United States)

Kim, Yoon-Hee; Jeong, Seul-Gi; Back, Kyeong-Hwan; Park, Ki-Hwan; Chung, Myung-Sub; Kang, Dong-Hyun

2013-09-16

The effect of various conditions on inactivation of foodborne pathogens and quality of fresh-cut lettuce during ultraviolet (254 nm, UVC) radiation was investigated. Lettuce was inoculated with a cocktail of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and treated at different temperatures (4 and 25 °C), distances between sample and lamp (10 and 50 cm), type of exposure (illuminated from one or two sides), UV intensities (1.36 to 6.80 mW/cm²), and exposure times (0.5 to 10 min), sequentially. UV treatment at 25 °C for 1 min achieved 1.45-, 1.35-, and 2.12-log reductions in surface-inoculated E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively, whereas the reduction of these pathogens at 4 °C was 0.31, 0.57, and 1.16 log, respectively. UV radiation was most effective when distance from UV lamp to the sample was minimal (10 cm) and radiation area was maximal (two-sided exposure). All UV intensities significantly (P0.05) different from those of nontreated samples up to 5 min exposure. However, these qualities significantly (Pradiation under optimized conditions could reduce foodborne pathogens without adversely affecting color quality properties of fresh-cut lettuce. © 2013 Elsevier B.V. All rights reserved.

Interactions between iron and titanium metabolism in spinach: A chlorophyll fluorescence study in hydropony

Czech Academy of Sciences Publication Activity Database

Cígler, Petr; Olejníčková, Julie; Hrubý, Martin; Cséfalvay, Ladislav; Peterka, J.; Kužel, S.

2010-01-01

Roč. 167, č. 18 (2010), s. 1592-1597 ISSN 0176-1617 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40500505; CEZ:AV0Z60870520 Keywords : chlorophyll fluorescence * iron * photosynthetic apparatus * spinach * titanium Subject RIV: CC - Organic Chemistry Impact factor: 2.677, year: 2010

Alkylperoxyl radical scavenging activity of red leaf lettuce (Lactuca sativa L.) phenolics.

Science.gov (United States)

Caldwell, Charles R

2003-07-30

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 (HPLC). The primary phenolic compounds in the leaf tissue extracts were mono- and dicaffeoyltartaric acid (CTA and DCTA), mono- and dicaffeoylquinic acid (CQA and DCQA), quercetin 3-malonylglucoside (QMG), quercetin 3-glucoside (QG), cyanidin 3-malonylglucoside (CMG), and an unknown phenolic ester (UPE). Significant levels of DCQA were only found after wounding. Using the new fluorescein-based ORAC assay procedures, fractions from the HPLC analyses were assayed for peroxyl radical absorbance capacity. Using absorbance to estimate concentration, the decreasing order of contribution to the total ORAC value of an extract from wounded tissue was QMG > DCQA > CMG > DCTA > UPE > QG > CTA. The decreasing order of the specific peroxyl radical scavenging activities was CMG > QG > DCTA > DCQA > QMG > UPE > CQA > CTA. Since the concentrations of plant flavonoid and phenolic acid esters are sensitive to environmental factors, this information may be used to develop pre- and postharvest conditions which increase the dietary benefits of leaf lettuce.

Incorporation of temperature and solar radiation thresholds to modify a lettuce downy mildew warning system

NARCIS (Netherlands)

Wu, B.M.; Bruggen, van A.H.C.; Subbarao, K.V.; Scherm, H.

2002-01-01

The effect of temperature on infection of lettuce by Bremia lactucae was investigated in controlled environment studies and in the field. In controlled conditions, lettuce seedlings inoculated with B. lactucae were incubated at 15, 20, 25, or 30°C during a 4-h wet period immediately after

Neural Network Modeling to Predict Shelf Life of Greenhouse Lettuce

Directory of Open Access Journals (Sweden)

Wei-Chin Lin

2009-04-01

Full Text Available Greenhouse-grown butter lettuce (Lactuca sativa L. can potentially be stored for 21 days at constant 0°C. When storage temperature was increased to 5°C or 10°C, shelf life was shortened to 14 or 10 days, respectively, in our previous observations. Also, commercial shelf life of 7 to 10 days is common, due to postharvest temperature fluctuations. The objective of this study was to establish neural network (NN models to predict the remaining shelf life (RSL under fluctuating postharvest temperatures. A box of 12 - 24 lettuce heads constituted a sample unit. The end of the shelf life of each head was determined when it showed initial signs of decay or yellowing. Air temperatures inside a shipping box were recorded. Daily average temperatures in storage and averaged shelf life of each box were used as inputs, and the RSL was modeled as an output. An R2 of 0.57 could be observed when a simple NN structure was employed. Since the "future" (or remaining storage temperatures were unavailable at the time of making a prediction, a second NN model was introduced to accommodate a range of future temperatures and associated shelf lives. Using such 2-stage NN models, an R2 of 0.61 could be achieved for predicting RSL. This study indicated that NN modeling has potential for cold chain quality control and shelf life prediction.

Colonization of lettuce rhizosphere and roots by tagged Streptomyces

Directory of Open Access Journals (Sweden)

Maria eBonaldi

2015-02-01

Full Text Available Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic.

Effects of pre-and postharvest lighting on quality and shelf life of fresh-cut lettuce

NARCIS (Netherlands)

Woltering, E.J.; Witkowska, I.M.

2016-01-01

The effects of pre-and postharvest lighting on quality and shelf life of fresh-cut lettuce was investigated. Lettuce was grown under different light intensities (120 and 250 μmol m^-2 s^-1 PAR from fluorescent tubes) and quality at harvest and subsequent postharvest

Effete of Gamma Radiation and N.P.K on Lettuce yield

International Nuclear Information System (INIS)

Abo Elkhier, O.H.M.M.

2013-01-01

Two field experiment were carried out during 2005/2006 winter growing seasons at the experiment at farm of Nuclear Research Center, Atomic Energy Authority, Inshas, Egypt – The experiments were conducted to study the effect of irradiated sowing seeds with 0, 2, 4, 6 and 8 Gray (Gy) of gamma radiation and / or the effect of different levels of NPK fertilizer 0, (NPK)1, (NPK)2, (NPK)3, (NPK)4 and (NPK)5 on the morphological and chemical parameters of the lettuce yield. The fresh weight of the plant in the line, length of the plant in the line, the number of leaves in the line, the number of plants in the line and the fresh weight in Fadden per ton were studied. There were significant effects of NPK contents on the lettuce leaves at (NPK) 4 in the dose level 6 Gy and on Calcium and Vitamins. We found that the most effective doses on leaf lettuce is 6 Gy dose of gamma radiation which gives strong and early seedlings in maturity upwards in the production of seedlings dose of 4 Gy. While the dose 8 Gray did not occur any increase at dose level 6 Gy. The Level (NPK) 4 increase the production of fresh per acre more upwards for all levels with 6 Gray and fourth level was the best in the natural qualities and characteristics of chemical terms of delay growth harvest lettuce, as well as influence on the plant content of calcium, nitrogen, protein and all the natural qualities among the first season and the second season.

Phosphorus levels in soil and lettuce production due to phosphorus fertilization

Directory of Open Access Journals (Sweden)

José Ricardo Mantovani

2014-09-01

Full Text Available The leafy vegetables are considered nutrient-demanding, but are scarce in the literature works about phosphorus fertilization. This study aimed to evaluate the effect of phosphate on the production of lettuce, content and amount of P accumulated in leaf plants, and to relate levels of P in the clayey soil with plant production. The experiment was conducted in a greenhouse in pots in a randomized block design with ten treatments and four replications. The treatments were made up of P, corresponding to 0, 50, 100, 150, 200, 300, 400, 500, 600 and 700 mg dm-3, as triple superphosphate powder. Portions of 6 dm3 of the clay soil (420 g kg-1 clay received lime, aimed at raising the V % soil to 70 %, equivalent to 20 t ha-1 of cattle manure, and the phosphate fertilizer according to the treatments, remaining incubated for about 30 days. At the end of incubation, each pot received a change of lettuce cultivar Verônica. The plant harvesting was performed 39 days after transplanting the seedlings. O P gave large increases in growth and production of lettuce, and culture responded positively to the application of high doses of the nutrient. A dose of 350 mg dm-3, equivalent to 800 kg ha-1 P2O5, was the most suitable for growing lettuce in the clay soil. In this work conditions, the phosphorus fertilizations it was necessary when the P-Mehlich contents in the clay soil were less than 75 mg dm-3.

A rapid and efficient in vitro regeneration system for lettuce (Lactuca sativa L.).

Science.gov (United States)

Armas, Isabel; Pogrebnyak, Natalia; Raskin, Ilya

2017-01-01

Successful biotechnological improvement of crop plants requires a reliable and efficient in vitro regeneration system. Lettuce ( Lactuca sativa L.), one the most important vegetable crops worldwide, is strongly genotype-dependent in terms of regeneration capacity, limiting the potential for biotechnological improvement of cultivars which show recalcitrance under currently available protocols. The effect of different nutrient sources, plant hormone combinations and activated charcoal supplementation on shoot induction efficiency was evaluated on the cultivar 'RSL NFR', which had previously shown poor regeneration efficiency. Multiple shoot organogenesis from cotyledon explants was recorded at the highest frequency and speed on Murashige and Skoog regeneration medium supplemented with 200 mg/l of activated charcoal, 3% sucrose, 10 mg/l benzylaminopurine and 0.5 mg/l naphthaleneacetic acid, which induced shoots through direct regeneration in 90.8 ± 7.9% of explants. High shoot induction efficiency was also observed, albeit not quantified, when using this medium on some other cultivars. This activated charcoal-containing regeneration medium might offer a rapid and efficient option for direct shoot induction in some lettuce genotypes that do not respond well to common lettuce regeneration protocols. This is also the first report of the effect of activated charcoal in lettuce tissue culture.

Effector-mediated discovery of a novel resistance gene against Bremia Lactucae in a nonhost lettuce species

NARCIS (Netherlands)

Giesbers, A.K.J.; Pelgrom, Alexandra; Visser, R.G.F.; Niks, R.E.; Ackerveken, Van Den Guido; Jeuken, M.J.W.

2017-01-01

Candidate effectors from lettuce downy mildew (Bremia lactucae) enable high-throughput germplasm screening for the presence of resistance (R) genes. The nonhost species Lactuca saligna comprises a source of B. lactucae R genes that has hardly been exploited in lettuce breeding. Its

Effector-mediated discovery of a novel resistance gene against Bremia lactucae in a nonhost lettuce species

NARCIS (Netherlands)

Giesbers, Anne K J; Pelgrom, Alexandra J E; Visser, Richard G F; Niks, Rients E; Van den Ackerveken, Guido; Jeuken, Marieke J W

2017-01-01

Candidate effectors from lettuce downy mildew (Bremia lactucae) enable high-throughput germplasm screening for the presence of resistance (R) genes. The nonhost species Lactuca saligna comprises a source of B. lactucae R genes that has hardly been exploited in lettuce breeding. Its

Feeding behaviour and performance of different populations of the black currant-lettuce aphid, Nasonovia ribisnigri, on resistant and susceptible lettuce

NARCIS (Netherlands)

Broeke, ten C.J.M.; Dicke, M.; Loon, van J.J.A.

2013-01-01

When crops are bred for resistance to herbivores, these herbivores are under strong selection pressure to overcome this resistance, which may result in the emergence of virulent biotypes. This is a growing problem for crop species attacked by aphids. The Nr-gene in lettuce confers near-complete

The inheritance of resistance to bacterial leaf spot of lettuce caused by Xanthomonas campestris pv. vitians in three lettuce cultivars

Science.gov (United States)

Lettuce yields can be reduced by the disease bacterial leaf spot (BLS) caused by the pathogen Xanthomonas campestris pv. vitians (Xcv) and host resistance is the most feasible method to reduce disease losses. The cultivars La Brillante, Pavane, and Little Gem express an incompatible host-pathogen in...

High-Resolution and Non-destructive Evaluation of the Spatial Distribution of Nitrate and Its Dynamics in Spinach (Spinacia oleracea L. Leaves by Near-Infrared Hyperspectral Imaging

Directory of Open Access Journals (Sweden)

Hao-Yu Yang

2017-11-01

Full Text Available Nitrate is an important component of the nitrogen cycle and is therefore present in all plants. However, excessive nitrogen fertilization results in a high nitrate content in vegetables, which is unhealthy for humans. Understanding the spatial distribution of nitrate in leaves is beneficial for improving nitrogen assimilation efficiency and reducing its content in vegetables. In this study, near-infrared (NIR hyperspectral imaging was used for the non-destructive and effective evaluation of nitrate content in spinach (Spinacia oleracea L. leaves. Leaf samples with different nitrate contents were collected under various fertilization conditions, and reference data were obtained using reflectometer apparatus RQflex 10. Partial least squares regression analysis revealed that there was a high correlation between the reference data and NIR spectra (r2 = 0.74, root mean squared error of cross-validation = 710.16 mg/kg. Furthermore, the nitrate content in spinach leaves was successfully mapped at a high spatial resolution, clearly displaying its distribution in the petiole, vein, and blade. Finally, the mapping results demonstrated dynamic changes in the nitrate content in intact leaf samples under different storage conditions, showing the value of this non-destructive tool for future analyses of the nitrate content in vegetables.

Glycolipids from spinach suppress LPS-induced vascular inflammation through eNOS and NK-κB signaling.

Science.gov (United States)

Ishii, Masakazu; Nakahara, Tatsuo; Araho, Daisuke; Murakami, Juri; Nishimura, Masahiro

2017-07-01

Glycolipids are the major constituent of the thylakoid membrane of higher plants and have a variety of biological and pharmacological activities. However, anti-inflammatory effects of glycolipids on vascular endothelial cells have not been elucidated. Here, we investigated the effect of glycolipids extracted from spinach on lipopolysaccharides (LPS)-induced endothelial inflammation and evaluated the underlying molecular mechanisms. Treatment with glycolipids from spinach had no cytotoxic effects on cultured human umbilical vein endothelial cells (HUVECs) and significantly blocked the expression of LPS-induced interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), and intracellular adhesion molecule-1 (ICAM-1) in them. Glycolipids treatment also effectively suppressed monocyte adhesion to HUVECs. Treatment with glycolipids inhibited LPS-induced NF-κB phosphorylation and nuclear translocation. In addition, glycolipids treatment significantly promoted endothelial nitric oxide synthase (eNOS) activation and nitric oxide (NO) production in HUVECs. Furthermore, glycolipids treatment blocked LPS-induced inducible NOS (iNOS) expression in HUVECs. Pretreatment with a NOS inhibitor attenuated glycolipids-induced suppression of NF-κB activation and adhesion molecule expression, and abolished the glycolipids-mediated suppression of monocyte adhesion to HUVECs. These results indicate that glycolipids suppress LPS-induced vascular inflammation through attenuation of the NF-κB pathway by increasing NO production in endothelial cells. These findings suggest that glycolipids from spinach may have a potential therapeutic use for inflammatory vascular diseases. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Molecular identification and biological characterization of a new potyvirus in lettuce.

Science.gov (United States)

Ciuffo, Marina; Mammella, Marco; Vallino, Marta; Caciagli, Piero; Turina, Massimo

2016-09-01

A potyvirus causing necrosis and leaf distortion on lettuce was found in the Lazio region of Italy. Host range analysis showed its ability to infect only Chenopodium quinoa and C. amaranticolor in addition to some lettuce cultivars. The virus could be transmitted by aphids of the species Myzus persicae. The complete 9829-nt genome was characterized. BLAST analysis of sequence of the complete encoded polyprotein showed that the most closely related virus is asparagus virus 1, with 52 % amino acid sequence identity. These results suggest that this virus should be considered a member of a new species in the genus Potyvirus.

Effect of pressure on the vacuum cooling of iceberg lettuce

Energy Technology Data Exchange (ETDEWEB)

Ozturk, Hande Mutlu [Pamukkale University, Food Engineering Department, Faculty of Engineering, Denizli (Turkey); Ozturk, Harun Kemal [Pamukkale University, Mechanical Engineering Department, Faculty of Engineering, 20070 Kinikli, Denizli (Turkey)

2009-05-15

Vacuum cooling is known as a rapid evaporative cooling technique for any porous product which has free water. The aim of this paper is to apply vacuum cooling technique to the cooling of the iceberg lettuce and show the pressure effect on the cooling time and temperature decrease. The results of vacuum cooling are also compared with conventional cooling (cooling in refrigerator) for different temperatures. Vacuum cooling of iceberg lettuce at 0.7 kPa is about 13 times faster than conventional cooling of iceberg lettuce at 6 C. It has been also found that it is not possible to decrease the iceberg lettuce temperature below 10 C if vacuum cooling method is used and vacuum pressure is set to 1.5 kPa. (author) [French] Le refroidissement sous vide est connu comme une technique evaporative rapide refroidissant pour n'importe quel produit poreux qui a de l'eau libre. Le but de ce papier est d'appliquer le refroidissement sous vide pour le refroidissement de la laitue et examiner l'effet de la pression sur le temps de refroidissement et la diminution de temperature. Les resultats de refroidissement sous vide sont aussi compares avec le refroidissement conventionnel (refroidissement dans le refrigerateur) pour les differentes temperatures. Le refroidissement a vide de laitue a 0.7 kPa est environ 13 fois plus vite que le refroidissement conventionnel de laitue croquante a 6 C. Il a ete aussi constate qu'il n'est pas possible de diminuer la temperature de laitue ci-dessous 10 C si le refroidissement sous vide est utilise comme methode et la pression a vide est montree a 1.5 kPa. (orig.)