Lettuce

Nitrates are found in fairly high concentrations in beets, spinach, kale, coUards, eggplant, celery, and lettuce. AdditionaHy, nitrates and nitrites are commonly used in the curing solutions of bacon, ham, and other cured meats. In cured meats, nitrates and nitrites control the growth of microorganisms, particularly Clostridium botulinum, and also serve as color preservatives. 

This study assesses the uptake of persistent organic pollutants (a-Endosulfan, P-Endosulfan and Endosulfan sulphate) from lettuce. The lettuce plants were grown on compost that had previously been contaminated at 10 and 50 J.g/g. 

Lettuce plants were grown under artificial day-light for 12 hours a day. The uptake of POPs was assessed by measuring the amount of Endosulfan compounds in roots and leaves from lettuce plants after 10, 20 and 33 days. In addition, control plants grown in uncontaminated soil were monitored and analysed. 

The influence of soil ageing on the recovery of POPs from spiked soil samples was also assessed. Spiked lettuce samples were subjected to in vitro gastrointestinal extraction to assess the bioavailability of Endosulfan compounds. All samples (soil and lettuce) were extracted using pressurised fluid extraction and analysed using gas chromatography with mass selective detection. 

In a study of the effect of nutrition on reproduction in the rat in the 1920s, Herbert Evans and Katherine Bishop found that rats failed to reproduce on a diet of rancid lard, unless lettuce or whole wheat was added to the diet. The essential factor was traced to a vitamin in the wheat germ oil. Named vitamin E by Evans (using the next available letter following on the discovery of vita-... 

Gift-jasmin, m. Carolina jasmine (Gelsemium sempervirens). -kies, m. arsenopyrite. -kobalt, m. native arsenic, -kraut, n. poisonous plant, -kunde, /. toxicology, -lattich, m. strong-scented lettuce (Lactuea virosa). -lehre, /. toxicology. 

Latdch, m. lettuce, -saure,/. lactucic acid. Latwerge,/. Pharm.) electuary, confection, lau,a. tepid, lukewarm mild. 

Salat, m. salad lettuce, -machen, n. (Breirinj ) doughing in and keeping the mash very cold, -ol, n. salad oil, specif, olive oil. 

An unknown analytical response in lettuce was detected61 and thought to contain P and S. The initial GC/MS Cl CH4 data were dominated by ions at m/z 121, 197 and 291 (equation 40). The GC/MS Cl NH3 data, however, indicated that perhaps the molecule had a higher molecular weight of 306 (MH+ equal to m/z 307, cf. equation 40). Comparison with the Cl CH4 and Cl NH3 spectra of demeton-S- (199) and demeton-O-sulfones showed, however, that the retention time and mass spectra of the former only matched the unknown (except the omission of the ion at m/z 307). On another stationary phase (OV-101) limited mass scanning of the ion at m/z 121 revealed a second unknown (200) eluting at 4.2 min (the major unknown, i.e. demeton-S-sulfone at 3.0 min). The molecular weight of 200 was believed to be 306. Because of the presence of ions at m/z 121,... 

Lettuce, cabbage, celery, turnip, biuegrass (kentucky), oats, maize, artichoke, tobacco, mustard, clover (sweet), squash, muskmeion Tolerant (4.0-6.0 ppm)... 

In a Food and Dmg Administration (FDA) summary of the levels of pesticides in ready-to-eat foods in the 10-year period from 1982 to 1991, methyl parathion was found 12 times in 8 kinds of food, at an average concentration of 0.0035 ppm (Kan-Do Office and Pesticides Team 1995). A 5-year analysis of domestic and imported foods and animal feeds for the years 1982-1986 detected 94 samples out of 19,851 total samples that contained methyl parathion (Hundley et al. 1988). Eighty-nine of the samples had concentrations in the range of 0.05-0.5 ppm, and five had levels ranging from 1.0 to 2.0 ppm. Methyl parathion was found in celery, citms, coriander, cantaloupe, Chinese peas, hay, alfalfa feed, Italian squash, lettuce, mustard greens, okra, parsley, peppers, spinach, strawberries, tomatillos, and tomatoes. 

Another groundwater contaminant that can be removed by reduction reactions is perchlorate. Ammonium perchlorate is a solid rocket fuel, and wastes from its manufacturing have contaminated some irrigation and drinking water sources, among them the lower Colorado River in the American Southwest. Elevated perchlorate levels have been linked to human health effects, and because perchlorate has been found in vegetable crops such as lettuce, there is concern that this contamination could have serious consequences. 

Boekhold AJ, Van der Schee HA, Kaandorp BH. 1989. [Rapid gas-chromatographic determination of trichloroethylene and/or tetrachloroethylene in lettuce by direct headspace analysis.] Z Lebensm Unters Forsch 189 550-553. (German)... 

BUGOS R 0 and yamamoto h y (1996) Molecular cloning of violaxanthin de-epoxidase from romaine lettuce and expression in Escherichia coli, Proc Natl Acad Sci, 93, 6320-25. 

Tomato, watermelon, pink grapefruit, papaya, guava, rose hip Carrot, apricot, mango, red pepper, kale, spinach, broccoli Carrot, collard green, pumpkin, corn, yellow pepper, cloudberry Kale, spinach, broccoli, pea, Brussels sprout, collard green, lettuce, corn, egg yolk... 

One acetyl group was identified at position 6 in highbush blueberries, " plums, " red leaf lettuce," and all grapes (Table 4.3.2) and at position 4 in Eurya japonica berries. Although acetyls were found in anthocyanins from strawberries " " and purple mashua, the positions of this acyl group were not assigned. 

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