Obligatory amino acids in primitive proteins

Conformational similarity among amino acid residues, a property derived by analysing (φ, ψ)-probability distributions of 20 proteinous amino acids from 38 different globular proteins, is used to arrive at a set of six ‘obligatory’ amino acids of primitive proteins. The amino acids Ser, Val, Leu, Asp, Gly and Pro have been argued to be ‘obligatory’ and to represent, conformationally, the remaining amino acids. The reasons for consideration of these six residues as ‘obligatory’ are discussed. Methods to check the validity of our proposition are suggested.     

Acetone-regulated synthesis and degradation of cytochrome P450E1 and cytochrome P4502B1 in rat liver [corrected

The regulation of CYP2E1 and 2B1 was studied by following mRNA levels, catalytic activities and the subcellular distribution of the apoproteins in rat liver 0, 6, 12, 24, 48 and 96 h after a single intragastric dose of acetone. No changes were observed in hepatic CYP2E1 mRNA levels at any time after acetone treatment, whereas rapid rises were observed in the microsomal amount of CYP2E1 protein and CYP2E1-catalyzed 4-nitrophenol hydroxylase and carbon-tetrachloride-initiated lipid-peroxidation activities. However, CYP2E1-dependent catalytic activities declined much faster than the immunodetectable CYP2E1 protein, suggesting that this cytochrome P-450 is inactivated prior to degradation. Similar results were seen in primary hepatocyte cultures. By contrast, concomitant changes in levels of CYP2B1 and CYP2B1-dependent O-depentylation of pentoxyresorufin were observed in the same microsomal preparations. Investigation of the degradative mechanism of both CYP2E1 and CYP2B1 by immunoquantitation of the proteins in lysosomes and by immunohistochemistry indicated their degradation via an autophagic-lysosomal pathway. The data suggest that CYP2E1 is acutely inactivated in the endoplasmic reticulum and that degradation of this isozyme occurs, at least in part, by the lysosomal route. By contrast, CYP2B1 is principally controlled at the level of synthesis.     

Microsatellite DNA in peach (Prunus persica L. Batsch) and its use in fingerprinting and testing the genetic origin of cultivars.

We isolated and sequenced 26 microsatellites from two genomic libraries of peach cultivar 'Redhaven', enriched for AC/GT and AG/CT repeats, respectively. For 17 of these microsatellites, it was possible to demonstrate Mendelian inheritance. Microsatellite polymorphism was assayed in 50 peach and nectarine cultivars. Of the 1300 PCRs carried out, all but two produced amplified products of the expected size. All microsatellites were polymorphic, showing 2-8 alleles per locus. Heterozygosity ranged from 0.04-0.74 (mean 0.47); the discrimination power (PD) ranged from 0.04-0.84 (mean 0.60). Cultivar heterozygosity varied greatly, with one cultivar ('Independence') being homozygous at all loci. The set of microsatellites discriminated all cultivars investigated, except several sport mutations, i.e., 'Dixitime' vs. 'Springcrest', 'Compact Redhaven' vs. 'Redhaven', and two pairs of cultivars, 'Venus' vs. 'Orion' and 'Elegant Lady' vs. 'Rome Star', whose pedigrees are controversial. We were able to analyze the paternity of several cultivars. In most cases, the parenthood was confirmed. The comparison of three long-living 'Redhaven' accessions supplied by different repositories did not provide any evidence of somatic instability of microsatellites. Hence, microsatellites, ranked according to their information content, are recommended as markers of choice for peach fingerprinting and suggestions are provided for interpreting band profiles and the correct sizing of alleles.     

The biological effects in animals related to the accident at the Chernobyl Atomic Electric Power Station. 1. The experimental model. The radiation loads on animals kept continuously under external and internal radiation exposure in the area of the Chernobyl Atomic Electric Power Station]

Irradiation conditions in which laboratory animals were kept in experimental laboratories of Chernobyl and Kiev after the accident at the Chernobyl A.P.S. are described. The data are presented on the spectral structural and activity of radionuclides in the diet as well as in the organs and tissues of the animals. The radiation loads have been estimated with regard to an external gamma component and the internal one contributed by the incorporated radionuclides. It has been shown that radiation doses received by the animals during their lifetime due to these contributions do not exceed units of cGy.     

The biological action of low-level radiation

On the basis of their own data and the literature the authors have analyzed the mechanism of biological action of low-level radiation on cells. In studying the harmful effect of gamma-radiation (10-40 cGy) on HeLa cells it was shown that damages occurred in 12 postirradiation generations. Analysis of cell distribution within the colonies has demonstrated that the share of colonies with low cell content and the number of giant cell increase. These data indicate that low-level radiation causes reproductive cell death that can occur not immediately but in later generations.     

Topochemistry of blood cells of the Gallus domesticus (Aves, Galliforme).

Blood smears of both male and female chicken Gallus domesticus were analysed by using the following topochemical methods: a) Periodic acid-Schiff (PAS) for glycogen. b) Mercury-bromophenol blue for protein. c) O-Toluidine for myeloperoxidase. d) Sudan black B for lipid. The PAS reaction revealed glycogen in the cytoplasm of all thrombocytes and in a few heterophils. The presence of proteins was evidenced in all types of cells. However variation in the intensity of staining of protein granules was observed in the fusiform structures of the heterophils. A negative reaction for myeloperoxidase was found in all cells. Although some evidence of myeloperoxidase activity was show in the polymorphonuclears it was not enough to ascertain a positive reaction. Lipids were detected in the cytoplasm of few heterophils, eosinophils and monocytes.     

Comparison of two techniques for quantifying environmental contaminants in human serum

Peak area matching and linear regression were used to quantify eight chlorinated pesticides and polychlorinated biphenyls (as Aroclor 1260) in human serum. There are no statistically significant differences in data obtained by these two quantifying techniques which were indicated by the paired t-test. For chlorinated pesticides, p = 0.053-0.62, and for polychlorinated biphenyls (as Aroclor 1260), p = 0.64. Analyte residues for the chlorinated pesticides ranged from 0.5 ppb for hexachlorobenzene (HCB) to 186 ppb for dichlorodiphenyldichloroethylene (DDE). Analyte residues for the polychlorinated biphenyls (as Aroclor 1260) ranged from 5-114 ppb. The absolute mean percent difference between the two quantifying techniques ranged from 0.06% for DDE to 8.06% for dieldrin (HEOD) among the chlorinated pesticides. The absolute mean percent difference between the two quantifying techniques for the polychlorinated biphenyls (as Aroclor 1260) was 3.4%. Peak area matching and linear regression were found to be comparable for quantifying these environmental residues in serum when the following conditions apply: 1) the concentration of the chlorinated pesticides is greater than or equal to 0.5 ppb (e.g., HCB, hexachlorocyclohexane (HCCH), oxychlordane (OC), heptachlor epoxide (HE), transnonachlor (TN), HEOD, and dichlorodiphenyltrichloroethane (DDT); 2) the concentration of the chlorinated pesticide is greater than or equal to 3 ppb (e.g., DDE); and 3) the total concentration of polychlorinated biphenyls (e.g., as Aroclor 1260) is greater than or equal to 5 ppb.