2,6-diaminopurine promotes repair of DNA lesions under prebiotic conditions

High-yielding and selective prebiotic syntheses of RNA and DNA nucleotides involve UV irradiation to promote the key reaction steps and eradicate biologically irrelevant isomers. While these syntheses were likely enabled by UV-rich prebiotic environment, UV-induced formation of photodamages in polymeric nucleic acids, such as cyclobutane pyrimidine dimers (CPDs), remains the key unresolved issue for the origins of RNA and DNA on Earth. Here, we demonstrate that substitution of adenine with 2,6-diaminopurine enables repair of CPDs with yields reaching 92%. This substantial self-repairing activity originates from excellent electron donating properties of 2,6-diaminopurine in nucleic acid strands. We also show that the deoxyribonucleosides of 2,6-diaminopurine and adenine can be formed under the same prebiotic conditions. Considering that 2,6-diaminopurine was previously shown to increase the rate of nonenzymatic RNA replication, this nucleobase could have played critical roles in the formation of functional and photostable RNA/DNA oligomers in UV-rich prebiotic environments

FAPRI 2004 U.S. and World Agricultural Outlook

Crop Production/Industries, Livestock Production/Industries,

FAPRI 2005 U.S. and World Agricultural Outlook

Crop Production/Industries, Livestock Production/Industries,

FAPRI 2001 U.S. and World Agricultural Outlook

Crop Production/Industries, Livestock Production/Industries,

FAPRI 2002 World Agricultural Outlook

Crop Production/Industries, Livestock Production/Industries,

The Doha Round of the WTO & Agricultural Market Liberalization: Impacts on Developing Economies

We investigate the impacts of multilateral removal of all border taxes and farm programs and their distortions on developing economies, using a world agriculture partial equilibrium model. We quantify changes in prices, trade flows, and production locations. Border measures and farm programs both affect world trade, but trade barriers have the largest impact. Following removal, trade expansion is substantial for most commodities, especially dairy, meats, and vegetable oils. Net agricultural and food exporters emerge with expanded exports; net importing countries with limited distortions before liberalization are penalized by higher world prices and reduced imports. We draw implications for current World Trade Organization negotiations

FAPRI 2003 U.S. and World Agricultural Outlook

The FAPRI 2003 World Agriculture Outlook presents final projections of FAPRI\u27s agricultural outlook on world agricultural production, consumption, and trade. FAPRI projections assume average weather patterns worldwide, existing policy, policy commitments under current trade agreements, and recent policy changes such as the Farm Security and Rural Investment Act of 2002. FAPRI projections do not include conjectures on potential policy changes such as the various proposals under consideration in the WTO Doha Round negotiations. The major macroeconomic drivers of the 2003 FAPRI baseline are the deepening crisis in Latin America,; full economic recovery in many countries in the next two years, and the U.S. dollar\u27s mixed relative value on world markets