Validity and repeatability of a simple index derived from the short physical activity questionnaire used in the European Prospective Investigation into Cancer and Nutrition (EPIC) study     

Wareham NJ  Jakes RW  Rennie KL  Schuit J  Mitchell J  Hennings S  Day NE 《Public health nutrition》2003,6(4):407-413

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Use of a substrate/alliinase combination to generate antifungal activity in situ   总被引：5，自引：0，他引：5  

Fry FH  Okarter N  Baynton-Smith C  Kershaw MJ  Talbot NJ  Jacob C 《Journal of agricultural and food chemistry》2005,53(3):574-580

Allicin, an active ingredient of garlic, possesses a range of antimicrobial properties. Unfortunately, certain properties of the compound, such as chemical instability and low miscibility with water, have hampered its practical use in the past. Here, we show that it is possible to use a binary system consisting of the plant enzyme alliinase and its substrate alliin to generate allicin, and hence antifungal activity, in situ. During application, the two inactive components generate compounds that inhibit growth and infection-related development of the rice blast fungus Magnaporthe grisea. It is therefore possible to "trigger" biological activity in a controlled, yet effective manner. Apart from circumventing many of the drawbacks of allicin, this binary system has additional important advantages, such as low toxicity of its individual components and selective activation. Importantly, alliinase is also able to use different substrates, therefore paving the way to a range of novel, binary antimicrobial systems with custom-made chemical and biochemical properties.  相似文献   

Carbon dioxide fixation     

Nicholas KM 《Science (New York, N.Y.)》1982,217(4555):148

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Geoscience. Natural complexity     

Watkins NW  Freeman MP 《Science (New York, N.Y.)》2008,320(5874):323-324

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Comment on "Major Australian-Antarctic plate reorganization at Hawaiian-Emperor bend time"     

Tikku AA  Direen NG 《Science (New York, N.Y.)》2008,321(5888):490; author reply 490

Whittaker et al. (Reports, 5 October 2007, p. 83) presented reconstructions for Australia and Antarctica showing a change in relative plate motion approximately 53 million years ago, coincident with an inferred major global plate reorganization. This comment addresses problematic areas in their assumptions and the geological consequences of their reconstructions.  相似文献   

DNA topoisomerase I--targeted chemotherapy of human colon cancer in xenografts   总被引：25，自引：0，他引：25  

B C Giovanella  J S Stehlin  M E Wall  M C Wani  A W Nicholas  L F Liu  R Silber  M Potmesil 《Science (New York, N.Y.)》1989,246(4933):1046-1048

Drug development is needed to improve chemotherapy of patients with locally advanced or metastatic colon carcinoma, who otherwise have an unfavorable prognosis. DNA topoisomerase I, a nuclear enzyme important for solving topological problems arising during DNA replication and for other cellular functions, has been identified as a principal target of a plant alkaloid 20(S)-camptothecin. Significantly increased concentrations of this enzyme, compared to that in normal colonic mucosa, were found in advanced stages of human colon adenocarcinoma and in xenografts of colon cancer carried by immunodeficient mice. Several synthetic analogs of camptothecin, selected by tests with the purified enzyme and tissue-culture screens, were evaluated in the xenograft model. Unlike other anticancer drugs tested, 20(RS)-9-amino-camptothecin (9-AC) induced disease-free remissions. The overall drug toxicity was low and allowed for repeated courses of treatment.  相似文献   

Boron-toxicity tolerance in barley arising from efflux transporter amplification   总被引：1，自引：0，他引：1  

Sutton T  Baumann U  Hayes J  Collins NC  Shi BJ  Schnurbusch T  Hay A  Mayo G  Pallotta M  Tester M  Langridge P 《Science (New York, N.Y.)》2007,318(5855):1446-1449

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The RAC of judgment     

Wade N 《Science (New York, N.Y.)》1980,207(4438):1451

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Discovery and directed evolution of a glyphosate tolerance gene   总被引：2，自引：0，他引：2  

Castle LA  Siehl DL  Gorton R  Patten PA  Chen YH  Bertain S  Cho HJ  Duck N  Wong J  Liu D  Lassner MW 《Science (New York, N.Y.)》2004,304(5674):1151-1154

The herbicide glyphosate is effectively detoxified by N-acetylation. We screened a collection of microbial isolates and discovered enzymes exhibiting glyphosate N-acetyltransferase (GAT) activity. Kinetic properties of the discovered enzymes were insufficient to confer glyphosate tolerance to transgenic organisms. Eleven iterations of DNA shuffling improved enzyme efficiency by nearly four orders of magnitude from 0.87 mM-1 min-1 to 8320 mM-1 min-1. From the fifth iteration and beyond, GAT enzymes conferred increasing glyphosate tolerance to Escherichia coli, Arabidopsis, tobacco, and maize. Glyphosate acetylation provides an alternative strategy for supporting glyphosate use on crops.  相似文献   

Paleoindian seafaring, maritime technologies, and coastal foraging on California's Channel Islands     

Erlandson JM  Rick TC  Braje TJ  Casperson M  Culleton B  Fulfrost B  Garcia T  Guthrie DA  Jew N  Kennett DJ  Moss ML  Reeder L  Skinner C  Watts J  Willis L 《Science (New York, N.Y.)》2011,331(6021):1181-1185

Three archaeological sites on California's Channel Islands show that Paleoindians relied heavily on marine resources. The Paleocoastal sites, dated between ~12,200 and 11,200 years ago, contain numerous stemmed projectile points and crescents associated with a variety of marine and aquatic faunal remains. At site CA-SRI-512 on Santa Rosa Island, Paleocoastal peoples used such tools to capture geese, cormorants, and other birds, along with marine mammals and finfish. At Cardwell Bluffs on San Miguel Island, Paleocoastal peoples collected local chert cobbles, worked them into bifaces and projectile points, and discarded thousands of marine shells. With bifacial technologies similar to those seen in Western Pluvial Lakes Tradition assemblages of western North America, the sites provide evidence for seafaring and island colonization by Paleoindians with a diversified maritime economy.  相似文献