منابع مشابه
Borate minerals stabilize ribose.
Evidence for an “RNA world,” an episode of life on Earth during which RNA was the only genetically encoded component of biological catalysts, is found in the ribosome (1), catalytic RNA molecules (2), and contemporary metabolism (3). That RNA could form spontaneously and persist under prebiotic conditions has been doubted, however (4, 5). Ribose and its sister pentoses (arabinose, xylose, and l...
متن کاملBorate Minerals and RNA Stability
The abiotic origin of genetic polymers faces two major problems: a prebiotically plausible polymerization mechanism and the maintenance of their polymerized state outside a cellular environment. The stabilizing action of borate on ribose having been reported, we have explored the possibility that borate minerals stabilize RNA. We observe that borate itself does not stabilize RNA. The analysis o...
متن کاملManganese minerals in geodes from Chihuahua, Mexico
Seven manganese minerals have been observed in geodes from Chihuahua, Mexico. Ramsdellite occurs in a number of different habits, but the morphology and precession X-ray patterns suggest that it is pseudomorphous after groutite. Pyrolusite is found only in association with ramsdellite and is believed to be an alteration product of that mineral. Todorokite generally occurs as a late-stage fibrou...
متن کاملPREBIOTIC CHEMISTRY Borate Minerals and Origin of the RNAWorld
The RNA World is generally thought to have been an important link between purely prebiotic (>3.7 Ga) chemistry and modern DNA/protein biochemistry. One concern about the RNAWorld hypothesis is the geochemical stability of ribose, the sugar moiety of RNA. Prebiotic stabilization of ribose by solutions associated with borate minerals, notably colemanite, ulexite, and kernite, has been proposed as...
متن کاملManganese oxide minerals: crystal structures and economic and environmental significance.
Manganese oxide minerals have been used for thousands of years-by the ancients for pigments and to clarify glass, and today as ores of Mn metal, catalysts, and battery material. More than 30 Mn oxide minerals occur in a wide variety of geological settings. They are major components of Mn nodules that pave huge areas of the ocean floor and bottoms of many fresh-water lakes. Mn oxide minerals are...
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ژورنال
عنوان ژورنال: Journal of the Mineralogical Society of Japan
سال: 1980
ISSN: 1883-7018,0454-1146
DOI: 10.2465/gkk1952.14.special3_86