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1.
The covalent binding of reactive metabolites of the carcinogen N-hydroxy-2-acetylaminofluorene to DNA and protein in isolated, intact rat liver nuclei was studied. The chemically synthesized 2-acetylaminofluorene-N-sulfate became covalently bound to DNA and protein to form adducts, 50% to 60% of which retained the N-acetyl group. Glutathione decreased the covalent binding of acetylated adducts to DNA by 18% and to protein by 50%. Methionine was more effective; it decreased DNA binding by 52% and protein binding by 79%. N-Hydroxy-2-acetylaminofluorene was deacetylated by the nuclear preparation. Almost exclusively, deacetylated 2-aminofluorene adducts to DNA and protein were formed. Glutathione decreased the covalent binding of deacetylated adducts to DNA by only 14%. Protein binding, however, was decreased by 57%. Methionine had no effect on the formation of these adducts to DNA and protein. Formation of 2-aminofluorene-glutathione conjugates was reduced by ascorbic acid by 65%. Covalent binding of deacetylated adducts to DNA and protein, however, was not decreased by ascorbic acid. These data suggest that "harder" nucleophiles like methionine can be used to protect macromolecules in vivo from damage by "hard" electrophiles such as those generated from the reactive 2-acetylaminofluorene-N-sulfate. However, such nucleophiles seem not to be effective with N-hydroxylamines, such as N-hydroxy-2-aminofluorene, formed by deacetylation of N-hydroxy-2-acetylaminofluorene. 相似文献
2.
Larvae ofPieris brassicae andMamestra brassicae use food on which they have been grown more efficiently than a novel food. This physiological adaptation to a certain food
may be regarded as a functional reason underlying changes in food selection behaviour due to previous experiences (“preference
induction”).
Larvae ofManduca sexta show a reduced efficiency of digestion when the diet contains nicotine or atropine, alkaloids occurring in acceptable food
plants. It is concluded that insects may spend a considerable amount of energy detoxifying host-plant specific allelochemics.
Le Prix Métabolique du Changement de Diète et de la Neutralisaton de Produits Allélochimiques
Résumé Les chenilles dePieris brassicae et deMamestra brassicae digèrent la nourriture où elles ont poussé d'une manière plus efficace qu'un nouveau genre de nourriture. Cette adaption physiologique à la nourriture est probablement la raison fontionnelle qui est à la base de changements dans le comportement du choix alimentaire qui sont en rapport avec des expériences antérieures (“induction d'une préférence”). L'efficacité de la digestion dans les chenilles deManduca sexta subit une diminution, quand on ajoute à leur aliment artificiel de la nicotine ou de l'atropine, des alcalo?des qu'on trouve dans des plantes nutritives acceptables. Voilà pourquoi nous en venons à la conclusion que les insectes consacrent parfois une quantité considérable d'énergie à la détoxication de matières allélochimiques qui se trouvent dans leur plante-h?te.相似文献
3.
JH Shazia Fathima Jayaraman Selvaraj Venkatacalam Sivabalan Umapathy Vidhya Rekha Rajagopal Ponnulakshmi Veeraraghavan Vishnupriya Malathi Kullappan Radhika Nalinakumari Sreekandan Surapaneni Krishna Mohan Periyasamy Vijayalakshmi 《Bioinformation》2021,17(1):212
The mTOR (mammalian or mechanistic Target of Rapamycin) is linked with oral cancer. Therefore, it is of interest to study the molecular docking-based binding of paclitaxel (a FDA approved drug for oral cancer) and its analogues with mTOR. Hence, we report the binding features of 10-Deacetyltaxol, 7-Epi-10-deacetyltaxol, 7-Epi-Taxol and 6alpha-Hydroxypaclitaxel with mTOR for further consideration. 相似文献
4.
Janine JH Oosterhof G Jolanda Elving Ietse Stokroos Arie van nieuw Amerongen Henny C van der Mei Henk J Busscher 《Biofouling》2013,29(6):347-353
The integrity of biofilms on voice prostheses used to rehabilitate speech in laryngectomized patients causes unwanted increases in airflow resistance, impeding speech. Biofilm integrity is ensured by extracellular polymeric substances (EPS). This study aimed to determine whether synthetic salivary peptides or mucolytics, including N-acetylcysteine and ascorbic acid, influence the integrity of voice prosthetic biofilms. Biofilms were grown on voice prostheses in an artificial throat model and exposed to synthetic salivary peptides, mucolytics and two different antiseptics (chlorhexidine and Triclosan). Synthetic salivary peptides did not reduce the air flow resistance of voice prostheses after biofilm formation. Although both chlorhexidine and Triclosan reduced microbial numbers on the prostheses, only the Triclosan-containing positive control reduced the air flow resistance. Unlike ascorbic acid, the mucolytic N-acetylcysteine removed most EPS from the biofilms and induced a decrease in air flow resistance. 相似文献
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Orhan H Vermeulen NP Tump C Zappey H Meerman JH 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,799(2):245-254
We developed an isotope dilution HPLC-atmospheric pressure chemical ionization-tandem mass spectrometry (HPLC-APCI-MS/MS) method for the simultaneous determination of p-tyrosine, phenylalanine, o,o'-dityrosine, m-tyrosine, o-tyrosine, 3-chlorotyrosine and 3-nitrotyrosine and 8-hydroxy-2'-deoxyguanosine (8-OHdG) that requires no extensive sample pre-treatment. p-[(2)H(4)]Tyrosine and o,o'-[(2)H(6)]dityrosine were used as internal standards. Calibration curves of the method were linear (r(2)=0.990-0.999) over a concentration range of 0.03-10 microM for o-tyrosine; 0.04-10 microM for 3-nitrotyrosine and 3-chlorotyrosine; 0.05-10 microM for o,o'-dityrosine; and for m-tyrosine; 1.0-100 microM for p-tyrosine and for phenylalanine; and 0.01-10 microM for 8-OHdG. The detection limits were from 0.025 to 0.05 microM for the tyrosine derivatives; 0.01 microM for 8-OHdG; and 0.5 microM for p-tyrosine and for phenylalanine, respectively. Within-day coefficients of variation (CV) for spiked human urine samples ranged from 2.7 to 7.0%, except for 8-OHdG (13.7%). Between-day variations ranged from 7.9 to 13.0%, except for o-tyrosine (CV = 18.2%), and for 8-OHdG (CV = 24.7%).The background levels of p-tyrosine, phenylalanine, o,o'-dityrosine, and o-tyrosine in morning urine of eight healthy volunteers were 3890+/-590, 3420+/-730, 5.8+/-0.3, and 9.2+/-1.5 micromol/mol creatinine, respectively. Using the present HPLC-APCI-MS/MS method, the urinary background levels of m-tyrosine, 3-chlorotyrosine, 3-nitrotyrosine and 8-OHdG were below the limit of detection. 相似文献
8.
Improved tests for heterogeneity across a region of DNA sequence in the ratio of polymorphism to divergence 总被引:15,自引:9,他引:6
The neutral theory of molecular evolution predicts that the ratio of
polymorphisms to fixed differences should be fairly uniform across a region
of DNA sequence. Significant heterogeneity in this ratio can indicate the
effects of balancing selection, selective sweeps, mildly deleterious
mutations, or background selection. Comparing an observed heterogeneity
statistic with simulations of the heterogeneity resulting from random
phylogenetic and sampling variation provides a test of the statistical
significance of the observed pattern. When simulated data sets containing
heterogeneity in the polymorphism-to-divergence ratio are examined,
different statistics are most powerful for detecting different patterns of
heterogeneity. The number of runs is most powerful for detecting patterns
containing several peaks of polymorphism; the Kolmogorov-Smirnov statistic
is most powerful for detecting patterns in which one end of the gene has
high polymorphism and the other end has low polymorphism; and a newly
developed statistic, the mean sliding G statistic, is most powerful for
detecting patterns containing one or two peaks of polymorphism with reduced
polymorphism on either side. Nine out of 27 genes from the Drosophila
melanogaster subgroup exhibit heterogeneity that is significant under at
least one of these three tests, with five of the nine remaining significant
after a correction for multiple comparisons, suggesting that detectable
evidence for the effects of some kind of selection is fairly common.
相似文献
9.
10.
Kees L. de Visser Gijs W. D. Landman Betty Meyboom-de Jong Wim de Visser Gerard J. te Meerman Henk J. G. Bilo 《PloS one》2015,10(7)
IntroductionThe development of type 2 diabetes results from an interaction of hereditary factors and environmental factors. This study aimed to investigate the contribution of interrelatedness to the risk of developing type 2 diabetes in an isolated Dutch population.ResultsPatients with type 2 diabetes were more interrelated, expressed by a higher KC compared to controls (7.2 vs. 5.2, p=0.001). First, second and third degree relatives had an increased risk of developing type 2 diabetes. Second degree relatives had a similar risk,1.7 (1.5-2.0) as third degree relatives,1.8 (1.5-2.2). Spouses of patients with diabetes had a 3.4 (2.7-4.4) higher risk of developing type 2 diabetes.ConclusionsInterrelatedness was higher among inhabitants with type 2 diabetes compared to controls. This differences extended beyond the nuclear family, thereby supporting the hypothesis that interrelatedness contributed to the development of type 2 diabetes on Urk. However, the size of this effect was small and the patterns of risk in first, second and third degree relatives suggested that factors other than interrelatedness were the main contributors to the development of type 2 diabetes on Urk. 相似文献