Purification and identification of linoleic acid hydroperoxides generated by soybean seed lipoxygenases 2 and 3     

Fukushige H  Wang C  Simpson TD  Gardner HW  Hildebrand DF 《Journal of agricultural and food chemistry》2005,53(14):5691-5694

It has been known that lipoxygenase (LOX) isozymes exhibit differences in product formation, but most product information to date is for LOX 1 among soybean (Glycine max) LOX isozymes. In this study, LOXs 2 and 3 were purified and used to generate hydroperoxide (HPOD) products in an in vitro system using linoleic acid as a substrate in the presence of either air or O2. The products were analyzed to determine their stereoisomeric characteristics. The control (no enzyme) showed only low levels of hydroperoxide production and no stereoisomeric specificity. LOX 2 shows high specificity in product formation, producing roughly 4 times more 13-HPOD than 9-HPOD, nearly all of which was 13-S(Z,E)-HPOD. LOX 3 produced more 9-HPOD than 13-HPOD at approximately a 2:1 ratio. No single stereoisomer was predominant among LOX 3 products. These results demonstrate that different isozymes of LOX have characteristic product profiles in in vitro reactions.  相似文献   

Supercritical carbon dioxide extraction of oil and squalene from amaranthus grain     

He HP  Corke H  Cai JG 《Journal of agricultural and food chemistry》2003,51(27):7921-7925

Supercritical carbon dioxide (SC CO(2)) was used for the extraction of oil and squalene from Amaranthus grain. Very small amounts of oil could be extracted by SC CO(2) from undisrupted grains, although SC CO(2) possesses higher diffusivity. Grinding increased the extraction rate and oil yield, and smaller particle size gave higher extraction rate. The oil yield and initial extraction rate increased linearly with the increasing SC CO(2) flow rate from 1 to 2 L/min. Increasing the flow rate of SC CO(2) above 2 L/min resulted in only a slight increase of oil yield and extraction rate. In the pressure range of 150-250 bar, extraction decreased with increasing temperature at a constant pressure, whereas at a pressure of 300 bar, the extraction yield increased with increasing temperature. Possible reasons for this are discussed. Effects of temperature and pressure on squalene yield were different from those on oil yield. A good oil yield (4.77 g of oil/100 g of grain) was obtained at 40 degrees C and 250 bar. The highest squalene yield (0.31 g of squalene/100 g of grain) and concentration (15.3% in extract) were obtained at 50 degrees C and 200 bar, although the oil yield under this condition was low (2.07 g of oil/100 g of grain). The moisture content within 0-10% had little influence on yields of oil and squalene at 40 degrees C and 250 bar. Finally, the oil yield and the squalene concentration in the extracts by SC CO(2) were compared to those by solvent extraction.  相似文献   

Oil and squalene in amaranthus grain and leaf     

He HP  Corke H 《Journal of agricultural and food chemistry》2003,51(27):7913-7920

Amaranthus grain of 104 genotypes from 30 species was investigated for oil and squalene contents and fatty acid profiles. The overall average oil content in Amaranthus grain was 5.0%, ranging from 1.9 to 8.7%. Squalene concentration in extracted oils ranged from trace to 7.3%, with an average concentration of 4.2%. The average contents of three major fatty acids in Amaranthus grain were 22.2, 29.1, and 44.6% for palmitic, oleic, and linoleic, respectively. The average fat content in dried mature leaves of 45 Amaranthus genotypes was 1.63%, ranging from 1.08 to 2.18%. The squalene concentration in leaf lipid extracts averaged 0.26%, ranging from trace to 0.77%, which is much lower than that from seeds. The major fatty acids of leaf extracts were linolenic, linoleic, and palmitic. Linolenic ranged from 56.5 to 62.0% of total fatty acids; linoleic, from 15.5 to 24.7%; and palmitic acid, from 13.5 to 15.5%. As for the fatty acid compositions at different growth stages, fatty acid content in leaf lipid was lower in mature leaves than in young leaves. The saturated/unsaturated ratio decreased when the leaf grew to maturity. Principal component analysis (PCA) was carried out on compositional characteristics of grain. The first two components accounted for 70% of the total variance (38.3 and 21.7%, respectively). There was a positive correlation between oil content and squalene yield, and a negative correlations were found between linoleic and either of the other two major fatty acids, palmitic and oleic. The taxonomic relationship among the species was also elucidated by PCA.  相似文献   

Epidemic strain of Venezuelan equine encephalomyelitis virus from a vampire bat captured in Oaxaca, Mexico, 1970   总被引：1，自引：0，他引：1  

P Correa-Giron  C H Calisher  G M Baer 《Science (New York, N.Y.)》1972,175(21):546-547

A vampire bat, Desmodus rotundus, captured in Oaxaca, Mexico, in August 1970, was found to be infected with the epidemic strain of Venezuelan equine encephalomyelitis virus at the same time that an equine epizootic was occurring there.  相似文献   

Using Conferences and Workshops for Technology Training     

Reetz  Harold F. 《Precision Agriculture》2002,3(4):319-325

Conference and workshop formats provide excellent opportunities in continuing education for farmers and their advisers to stay abreast of new technology and practices for maintaining high-yield, high-profit management systems. Where possible hands-on opportunities should be included and proceedings published to help support the learning process. Communication and cooperation between industry and universities have been enhanced through these meetings. Since adoption of new technologies is often a team effort involving the farmers, input suppliers and other stakeholders, training programs should be designed to foster cooperation among them. The complexity of some of the new technologies makes the hands-on workshop and demonstration formats especially valuable.  相似文献   

Theology and agricultural ethics at state universities: A rejoinder     

Richard A. Baer Jr. 《Agriculture and Human Values》1989,6(3):99-104

Michael Eldridge's critique of the author's earlier paper on the place of theology in agricultural ethics at state universities fails in at least three places: (1) Eldridge presents an inadequate picture of how basic assumptions function in human thinking and misuses terms like public, private, particular, empirical, and common experience; (2) he wrongly distinguishes between philosophers and theologians on the bais of their openness to new data, ideas, and public criticism; (3) he misunderstands the meaning of the First Amendment. Baer argues that whenever faculty at a state university deal with the Big Questions—who we are, how we should live, and what it all means—they must be seen, for First Amendment purposes, as operating within the realm of religion. Without such a functional definition of religion, the state will inevitably give unfair advantage to nontheistic, secular answers to the Big Questions. Eldridge is wrong to claim that Dewey escapes the liabilities of particularity and parochialism in a way that theologians do not. He also misunderstands the nature of the First Amendment when he argues that public schools may legitimately propagate Dewey's naturalistic variety of religion. Baer claims that when state universities address the Big Questions, the demands of public justice will be met only if theologians participate in the discussion and debate.Richard A. Baer, Jr. is professor of environmental ethics at Cornell University and a Fellow of the Center for Public Justice in Washington, D.C.  相似文献   

Seeding and propagation of untransformed mouse mammary cells in the lung     

Podsypanina K  Du YC  Jechlinger M  Beverly LJ  Hambardzumyan D  Varmus H 《Science (New York, N.Y.)》2008,321(5897):1841-1844

The acquisition of metastatic ability by tumor cells is considered a late event in the evolution of malignant tumors. We report that untransformed mouse mammary cells that have been engineered to express the inducible oncogenic transgenes MYC and Kras(D12), or polyoma middle T, and introduced into the systemic circulation of a mouse can bypass transformation at the primary site and develop into metastatic pulmonary lesions upon immediate or delayed oncogene induction. Therefore, previously untransformed mammary cells may establish residence in the lung once they have entered the bloodstream and may assume malignant growth upon oncogene activation. Mammary cells lacking oncogenic transgenes displayed a similar capacity for long-term residence in the lungs but did not form ectopic tumors.  相似文献   

PREPARATION OF 1-GLYCERIC ALDEHYDE     

Baer E  Fischer HO 《Science (New York, N.Y.)》1938,88(2274):108

  相似文献   

The mass disruption of Oort cloud comets     

Levison HF  Morbidelli A  Dones L  Jedicke R  Wiegert PA  Bottke WF 《Science (New York, N.Y.)》2002,296(5576):2212-2215

We have calculated the number of dormant, nearly isotropic Oort cloud comets in the solar system by (i) combining orbital distribution models with statistical models of dormant comet discoveries by well-defined surveys and (ii) comparing the model results to observations of a population of dormant comets. Dynamical models that assume that comets are not destroyed predict that we should have discovered approximately 100 times more dormant nearly isotropic comets than are actually seen. Thus, as comets evolve inward from the Oort cloud, the majority of them must physically disrupt.  相似文献   

Physiology. Heeding the hormonal call     

Zakon H 《Science (New York, N.Y.)》2004,305(5682):349-350

  相似文献