During extension, the continental lithosphere thins and breaks up, forming either wide or narrow rifts depending on the thermo-mechanical state of the extending lithosphere. Wide continental rifts, which can reach 1,000 km across, have been extensively studied in the North American Cordillera and in the Aegean domain. Yet, the evolutionary process from wide continental rift to continental breakup remains enigmatic due to the lack of seismically resolvable data on the distal passive margin and an absence of onshore natural exposures.
View Article and Find Full Text PDFThe nucleotide sequence of pVB131 containing the gene coding for a 130-kDa Bacillus thuringiensis israelensis (B.t.isr) mosquitocidal protein was determined.
View Article and Find Full Text PDFProc R Soc Lond B Biol Sci
February 1972
It was shown that 100mug quantities of 4,4'-dimethyl[2-(3)H(2)]cholesta-8,14-dien-3beta-ol (IIIa), tritiated cholesta-8,14-dien-3beta-ol, 4,4'-dimethyl[2-(3)H(2)]cholesta-7,14-dien-3beta-ol, dihydro[2-(3)H(2)]lanosterol and [24-(3)H]lanosterol were converted by a 10000g supernatant of rat liver homogenate into cholesterol in 17%, 54%, 6%, 9.5% and 24% yields respectively. From an incubation of dihydro[3alpha-(3)H]lanosterol with a rat liver homogenate in the presence of a trap up to 38% of the radioactivity was found to be associated with a fraction that was unambiguously shown to be 4,4'-dimethylcholesta-8,14-dien-3beta-ol.
View Article and Find Full Text PDFIt is shown that during the saturation of steroid carbon-carbon double bonds at Delta(24,25) and Delta(14,15) the ;hydride ion' originates from the 4B side of the NADPH.
View Article and Find Full Text PDF1. A mechanism for the removal of the 14alpha-methyl group in ergosterol biosynthesis that involves the intermediacy of an 8,14-diene system is outlined. 2.
View Article and Find Full Text PDFThe biosynthesis of cholesterol from squalene and tritiated water is described. Degradation of the cholesterol indicated that C-15 may be involved in cholesterol biosynthesis. In accordance with this view it is shown that in the conversion of [2RS-(3)H(2)]mevalonic acid into cholesterol one of the hydrogen atoms at C-15 is removed.
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