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Thirty-four cytochrome P-450 sequences from one bacterial and six
vertebrate species have been aligned with the aid of a computer alignment
algorithm. Phylogenetic trees were constructed using the
unweighted-pair-group and neighbor-joining methods. The two trees differed
at only a single branch point near the base of the tree. The cytochrome
P-450 superfamily of proteins clustered into eight families and contained
16 gene-duplication events. The first gene duplication occurred
approximately 1,360 Myr before the present (Mybp) and gave rise to
cytochrome P-450s found in two different cellular organelles, the
mitochondria and the endoplasmic reticulum. Both groups utilize cholesterol
or its metabolites as substrates, implying that cholesterol existed greater
than 1,360 Mybp. The fourth gene duplication (approximately 900 Mybp) gave
rise to the drug-metabolizing P-450s. These proteins aid in the
detoxification of foreign chemicals, as opposed to the metabolism of
endogenous compounds. The importance of the capacity to metabolize drugs is
reflected in 11 further gene duplications occurring in this lineage. The
first occurred approximately 800 Mybp and gave rise to the two major P-450
families, the phenobarbital and 3-methylcholanthrene families. An apparent
increase in the rate of cytochrome P-450 evolution is noted between the
bird-mammal divergence (300 Mybp) and the mammalian radiation (75 Mybp).
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Noviandi CT Razzazi E Agus A Böhm J Hulan HW Wedhastri S Maryudhani YB Nuryono Sardjono Leibetseder J 《Mycotoxin Research》2001,17(2):174-177
A survey was conducted between 1998–1999 to evaluate the level of aflatoxin B1 (AfB1) contamination in some selected Indonesian food products, mainly peanuts and peanut products for sale in supermarkets or traditional markets in Yogyakarta, Indonesia. Quantitative analysis was carried out on 118 samples using the ELISA (Enzyme-Linked Immunosorbent Assay) technique. The results indicate that (61.1%) samples were contaminated with AfB1 at range 2.0 to 249.0 μg/kg. Approximately 50% of the baby food products analysed were contaminated with AfB1 and the maximum level found was 7.0 μg/kg. In corn products and fermented products, AfB1 was detected in 66.7 and 50.0% of samples, respectively. A level as high as 5.6 μg/kg of AfB1 was found in the corn and 6.0 μg/kg in fermented product. AfB1 was also detected in all rice products, feed products, and other processed products at levels of up to 7.0, 27.0, and 26.0 μg/kg, respectively. 相似文献