953 resultados para Hydrologic sciences|Civil engineering|Environmental engineering
Resumo:
Peppermint (Mentha × piperita L.) was independently transformed with a homologous sense version of the 1-deoxy-d-xylulose-5-phosphate reductoisomerase cDNA and with a homologous antisense version of the menthofuran synthase cDNA, both driven by the CaMV 35S promoter. Two groups of transgenic plants were regenerated in the reductoisomerase experiments, one of which remained normal in appearance and development; another was deficient in chlorophyll production and grew slowly. Transgenic plants of normal appearance and growth habit expressed the reductoisomerase transgene strongly and constitutively, as determined by RNA blot analysis and direct enzyme assay, and these plants accumulated substantially more essential oil (about 50% yield increase) without change in monoterpene composition compared with wild-type. Chlorophyll-deficient plants did not afford detectable reductoisomerase mRNA or enzyme activity and yielded less essential oil than did wild-type plants, indicating cosuppression of the reductoisomerase gene. Plants transformed with the antisense version of the menthofuran synthase cDNA were normal in appearance but produced less than half of this undesirable monoterpene oil component than did wild-type mint grown under unstressed or stressed conditions. These experiments demonstrate that essential oil quantity and quality can be regulated by metabolic engineering. Thus, alteration of the committed step of the mevalonate-independent pathway for supply of terpenoid precursors improves flux through the pathway that leads to increased monoterpene production, and antisense manipulation of a selected downstream monoterpene biosynthetic step leads to improved oil composition.
Resumo:
Vol. 11 of the 2d ser. consists of one number only (no. 43).
Resumo:
Includes bibliography.
Resumo:
National Highway Traffic Safety Administration, Washington, D.C.
Resumo:
Mode of access: Internet.
Resumo:
"July 1978."
Resumo:
"Not for publication."
Resumo:
Mode of access: Internet.
Resumo:
Cover title.
Resumo:
Description based on: 1923/1924.
Resumo:
"A journal of civil engineering and construction." (Varies).
Resumo:
Vol. 11 of the 2d ser. consists of one number only (no. 43).
Resumo:
Description based on: Aug. 1910; title from cover.
Resumo:
Mode of access: Internet.
Resumo:
Mode of access: Internet.