1
|
Abstract
The action of dichlorvos (2.2-dichlorovinyldimethyl phosphate) was studied with a short-term in vitro system which utilizes human lymphocytes. The parameters studied were the action exerted by the pesticide on scheduled (semiconservative) and unscheduled (reparative) DNA synthesis measured as tritiated thymidine uptake. The results obtained show that dichlorvos affects semiconservative DNA synthesis, damages human lymphocyte DNA inducing low reparative synthesis, and interferes with DNA repair processes after damage exerted by ultraviolet rays.
Collapse
|
2
|
Dedek W. Guanine N7-alkylation in mice in vivo by metrifonate - discussion of possible genotoxic risk in mammals. ACTA PHARMACOLOGICA ET TOXICOLOGICA 2009; 49 Suppl 5:40-50. [PMID: 7344410 DOI: 10.1111/j.1600-0773.1981.tb03251.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Following intraperitoneal administration to male mice (strain AB Jena/Halle) of 14CH3-labelled metrifonate, 22 Ci/mol, in dosages of 0.48, 0.40 and 0.065 mmol/kg, DNA from liver and kidneys was analysed for 14C in N-7 methylguanine (7-MeG). The extent of methylation in liver was found to be maximal at 6 hrs after injection in amounts of 6-8 and 0.8 mumol 7-MeG/mol guanine for the high and the low dose, corresponding to a covalent binding index CBI 4-5. The half-life of excretion of 7-MeG was 5 hrs for the high and 15 hrs for the low dose. The extent of methylation at 0-6 of guanine was estimated to be around 0.002-0.01 mumol 0-6 MeG/mol guanine. Data from references concerning methyl methanesulfonate and dimethyl sulfate are compared with those of metrifonate and the genotoxic response of methylating and non-methylating metabolites is discussed.
Collapse
|
3
|
Segerbäck D, Ehrenberg L. Alkylating properties of dichlorvos (DDVP). ACTA PHARMACOLOGICA ET TOXICOLOGICA 2009; 49 Suppl 5:56-66. [PMID: 7344412 DOI: 10.1111/j.1600-0773.1981.tb03253.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Dichlorvos (DDVP) is a methylating agent. In DNA from mice given 1.9 x 10(-6) mol/kg of DDVP, a degree of alkylation of guanine-N-7 amounting to 8 x 10(-13) mol methyl per g DNA, was found. From this, a rate of clearance of 29 hr-1 was estimated. This value is in reasonable agreement with the value (55 hr-1), calculated from published data on the concentration over time of DDVP in the brain after injection of the compound in mice. Applying a risk estimation on humans exposed to DDVP, the genetic risk connected with the methylating activity of DDVP is low or very low. Comparing the mutagenic effectiveness of DDVP with that of methyl methanesulfonate, indicates that DDVP is more effective than expected from reaction kinetic data. The possible contribution of the dichloroacetaldehyde formed in vivo from DDVP has to be evaluated before a complete risk estimate can be made for DDVP.
Collapse
|
4
|
SEGERBÅCK D. Estimation of genetic risks of alkylating agents. V. Methylation of DNA in the mouse by DDVP (2,2-dichlorovinyl dimethyl phosphate)1. Hereditas 2009. [DOI: 10.1111/j.1601-5223.1981.tb01734.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
5
|
Review of the in vitro and in vivo genotoxicity of dichlorvos. Regul Toxicol Pharmacol 2007; 49:316-26. [DOI: 10.1016/j.yrtph.2007.08.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 08/24/2007] [Accepted: 08/25/2007] [Indexed: 11/18/2022]
|
6
|
Aquilina G, Benigni R, Bignami M, Calcagnile A, Dogliotti E, Falcone E, Carere A. Genotoxic activity of dichlorvos, trichlorfon and dichloroacetaldehyde. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780150504] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
7
|
Opinion of the Scientific Panel on Plant protection products and their residues (PPR) related to the evaluation of dichlorvos in the context of Council Directive 91/414/EEC. EFSA J 2006. [DOI: 10.2903/j.efsa.2006.343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
8
|
Khandelwal G, Wedzicha B. Reaction of Dichlorvos, dichloroacetaldehyde and related compounds with nucleophiles and phenols. Food Chem 1998. [DOI: 10.1016/s0308-8146(97)00116-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
9
|
Yamano T. Dissociation of DDVP-induced DNA strand breaks from oxidative damage in isolated rat hepatocytes. Toxicology 1996; 108:49-56. [PMID: 8644117 DOI: 10.1016/s0300-483x(95)03271-g] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Dichlorvos (DDVP)-induced DNA single strand breaks were investigated in isolated rat hepatocytes. In a dose-response study in hepatocytes from PB-treated rats (80 mg/kg i.p., for 3 days), 250 microM DDVP substantially reduced cellular non-protein sulfhydryl (NPSH) content, but had no detectable effect on DNA. At 500 microM, the increase in DNA single strand breaks was significant, with a slight increase in cellular lipid peroxidation. At doses over 1000 microM DDVP, cell death was accompanied with considerable lipid peroxidation, and DNA single strand breaks were evident. When the antioxidant N,N'-diphenyl-p-phenylene diamine (DPPD) was added or if the hepatocytes were incubated under air instead of 95% O2, lipid peroxidation and cell death were attenuated but DNA single strand breaks and reduction in NPSH content were not. On the other hand, ferrous iron-induced DNA single strand breaks, lipid peroxidation, and depletion of NPSH content were all attenuated by DPPD or by incubating the cells under air. With respect to the subcellular lipid peroxidation, DDVP caused a significant increase mainly in the microsomal fraction, whereas ferrous iron caused rapid and substantial increases in mitochondrial, microsomal, and nuclear fractions. There were more DNA single strand breaks caused by N-nitrosodiethylamine (NDEA), which becomes genotoxic after microsomal metabolism, in hepatocytes from PB-treated rats than in those from control rats. The number of these breaks was reduced by adding the cytochrome P450 inhibitor metyrapone. On the other hand, the effect of DDVP on DNA was not affected by modification of the cytochrome P450 status. These results suggest that lipid peroxidation induced by DDVP in isolated rat hepatocytes plays a significant role in its cytotoxicity but not in its genotoxicity.
Collapse
Affiliation(s)
- T Yamano
- Osaka City Institute of Public Health and Environmental Sciences, Japan
| |
Collapse
|
10
|
Chan PC, Huff J, Haseman JK, Alison R, Prejean JD. Carcinogenesis studies of dichlorvos in Fischer rats and B6C3F1 mice. Jpn J Cancer Res 1991; 82:157-64. [PMID: 1900819 PMCID: PMC5918371 DOI: 10.1111/j.1349-7006.1991.tb01823.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Dichlorvos (dichlorovinyl dimethyl phosphoric acid ester) is a cholinesterase inhibitor used widely as a contact and stomach insecticide for control of internal and external parasites. Carcinogenesis studies were conducted by administering dichlorvos in corn oil by gavage 5 times a week for 103 weeks to groups of 50 male and 50 female Fischer rats at 0, 4, or 8 mg/kg body weight, to groups of 50 male B6C3F1 mice at 0, 10, or 20 mg/kg, and to groups of 50 female B6C3F1 mice at 0, 20, or 40 mg/kg. During the course of the studies, body weights and survival rates of the male and female rats and mice were not different from those of their respective controls; females of both species appeared to gain more weight than controls. Neoplasms induced by dichlorvos included adenomas of the exocrine pancreas (male rats), mononuclear cell leukemia (male rats), and squamous cell papilloma of the forestomach (male and female mice; two other female mice had squamous cell carcinomas). Lesions observed in female rats that may have been due to dichlorvos administration included adenomas of the exocrine pancreas and fibroadenomas of the mammary gland. The results demonstrated that dichlorvos is carcinogenic for Fischer rats and B6C3F1 mice.
Collapse
Affiliation(s)
- P C Chan
- National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
| | | | | | | | | |
Collapse
|
11
|
Abstract
Widespread use of pesticides has no doubt benefited human beings in one way or another. However, their side effects on various organisms, including nontarget organisms, are largely overlooked. In the recent past, several studies have been done to assess the effects of pesticides on nontarget organisms, including microorganisms. Although pesticide effects on growth parameters of microorganisms have been extensively reviewed, little attention has been paid regarding their cytological and biochemical aspects. Therefore, the present work is mainly concerned with the cytological and biochemical aspects of pesticide microbiology. The effects of pesticides on photosynthesis, respiration, proteins, and nucleic acids are reviewed. Attention is also paid to their effects on cell morphology and morphogenesis and their effect on cell constituents.
Collapse
Affiliation(s)
- A K Tripathi
- Water Pollution Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| |
Collapse
|
12
|
Behera BC, Bhunya SP. Genotoxic potential of an organophosphate insecticide, phosphamidon (dimecron): an in vivo study in mice. Toxicol Lett 1987; 37:269-77. [PMID: 3617102 DOI: 10.1016/0378-4274(87)90142-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The genotoxic effect of phosphamidon in mice in an in vivo test system was investigated by 3 different assays: chromosomal aberration, micronucleus and sperm-shape abnormality. The chemical was administered to groups of mice via 3 routes (i.p., p.o. and s.c.), acutely in 3 dose regimens (5, 4 and 3 mg/kg) and subacutely or chronically (5 X 1 mg/kg). The animals were sacrificed at different times: after 6, 24, 48 and 120 h for chromosomal aberration, 30 h for micronucleus and 35 days for sperm-shape abnormality. Significant effects were observed in all assays. Chronic exposure to fractionated doses induced less effect than the equivalent acute dose. The results were dose- as well as time-responsive and indicated the genetic peril of phosphamidon in the present, in vivo system.
Collapse
|
13
|
Kligerman AD, Erexson GL, Wilmer JL. Induction of sister-chromatid exchange (SCE) and cell-cycle inhibition in mouse peripheral blood B lymphocytes exposed to mutagenic carcinogens in vivo. Mutat Res 1985; 157:181-7. [PMID: 3875033 DOI: 10.1016/0165-1218(85)90114-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
To determine the sensitivity of the mouse peripheral blood lymphocyte (PBL) culture system, male B6C3f1 mice were injected i.p. with either 2-acetylaminofluorene (AAF) (20, 40, 80, 160 mg/kg), benzo[a]pyrene (BP) 25, 75, 150, 300 mg/kg), dichlorvos (DCV) (5, 15, 25, 35 mg/kg), ethyl methanesulfonate (EMS) (10, 30, 90, 180, 270 mg/kg), or N-nitrosomorpholine (NM) (37.5, 75, 150, 300 mg/kg) dissolved in either RPMI 1640 (DCV, EMS, NM) or sunflower oil (AAF, BP). 24 h later blood was removed by cardiac puncture, and the lymphocytes were cultured in the presence of lipopolysaccharide for analysis of SCE in B lymphocytes. All 4 mutagenic carcinogens (AAF, BP, EMS, NM) induced significant dose-related increases in SCE frequency. DCV, a potent neurotoxicant, caused no change in the baseline SCE frequency. At the highest concentration of each chemical examined, AAF caused a 1.6-fold increase, EMS a 1.8-fold increase, NM a 3.0-fold increase, and BP a 3.1-fold increase in SCE frequency compared to concurrent controls. A comparison of these results for PBLs with those reported in the literature for bone marrow cells indicates that PBLs offer a good quantitative and qualitative estimate of the SCE-inducing potential for these 5 compounds in bone marrow cells.
Collapse
|
14
|
|
15
|
|
16
|
Nishio A, Uyeki EM. Nuclease-sensitivity of methylated DNA as a probe for chromatin reconstitution by genotoxicants. Biochem Biophys Res Commun 1982; 107:485-91. [PMID: 7126225 DOI: 10.1016/0006-291x(82)91517-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
17
|
Lal R. Accumulation, metabolism, and effects of organophosphorus insecticides on microorganisms. ADVANCES IN APPLIED MICROBIOLOGY 1982; 28:149-200. [PMID: 6765017 DOI: 10.1016/s0065-2164(08)70235-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
18
|
Nishio A, Uyeki EM. Induction of sister chromatid exchanges in Chinese hamster ovary cells by organophosphate insecticides and their oxygen analogs. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1981; 8:939-46. [PMID: 7338954 DOI: 10.1080/15287398109530128] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Induction of sister chromatid exchanges (SCEs) in cultures of Chinese hamster ovary cells by 10 anticholinesterase organophosphate insecticides was investigated. The insecticides were two phosphates (dichlorvos and dicrotophos), four sulfur-containing organophosphates (malathion, parathion, leptophos, and diazinon), and four oxygen analogs of the latter (malaoxon, paraoxon, leptophosoxon, and diazoxon). All of the compounds except diazinon induced statistically significant increases in SCE frequencies at concentrations between 0.03 and 1.0 mM. These results suggest that SCE induction is a common property of organophosphate insecticides. Compared to the sulfur-containing organophosphates, the oxygen analogs consistently produced higher SCE frequencies and had stronger antiproliferative activity. Compared to two known genotoxicants, doxorubicin and ethyl methanesulfonate, the ability of organophosphates to produce SCEs is much weaker.
Collapse
|
19
|
Czajkowska A, Walter Z. Effect of malathion on nucleic acid synthesis in phytohemagglutinin-stimulated human lymphocytes. Hum Genet 1980; 56:189-94. [PMID: 6161081 DOI: 10.1007/bf00295693] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The effect of malathion, an organophosphorus insecticide, on DNA and RNA synthesis was investigated by measuring the rate of incorporation of 3H thymidine and 3H uridine, respectively, into human lymphocytes stimulated by phytohemagglutinin (PHA). Increasing concentrations of malathion, from 10 to 70 micrograms/ml, were added to human lymphocyte cultures at different times in relation to PHA introduction. The lowest applied dose of malathion (10 micrograms/ml) in most cases led to increased incorporation of both 3H thymidine and 3H uridine. Higher concentrations of malathion (30, 50, 70 micrograms/ml) caused a time- and dose-dependent decrease of radioisotope incorporation.
Collapse
|
20
|
Ramel C, Drake J, Sugimura T. International Commission for Protection against Environmental Mutagens and Carcinogens. ICPEMC publication No. 5: An evaluation of the genetic toxicity of dichlorvos. Mutat Res 1980; 76:297-309. [PMID: 6782471 DOI: 10.1016/0165-1110(80)90021-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
21
|
Oliński R, Walter Z, Wiaderkiewicz R, Lukásová E, Palecek E. Changes in DNA properties due to treatment with the pesticides malathion and DDVP. RADIATION AND ENVIRONMENTAL BIOPHYSICS 1980; 18:65-72. [PMID: 7443982 DOI: 10.1007/bf01324375] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Properties of calf thymus DNA were investigated after treatment with the pesticides malathion (0,0-dimethyl-S-(1,2-bis ethoxycarbonyl ethyl)dithiophosphate) and DDVP (0,0-dimethyl-0-(2,2 dichlorovinyl)phosphate) in vitro by means of derivative (differential) pulse polarography (DPP), thermal denaturation curves recorded spectrophotometrically (Tm), viscometric measurements, and chromatography on the hydroxyapatite column. Changes in the properties of DNA were observed by means of DPP after only a few hours incubation with the pesticides, whereas the other methods did not detect any changes even after 48 h. The results obtained by DPP indicate that single-stranded segments and thermolabile regions are formed in DNA due to the action of the pesticides. This behaviour could perhaps be a consequence of guanine alkylation followed by depurination and chain scission at elevated temperatures. Malathion and DDVP differ in the kinetics of reaction with double-helical DNA. DDVP is more reactive and its action is also manifested after 72 h in changes in viscosity, Tm, and chromatographic behaviour on the hydroxyapatite column. The changes induced by malathion were, under identical conditions, not detectable by these methods.
Collapse
|
22
|
Lal R, Saxena DM. Cytological and biochemical effects of pesticides on microorganisms. RESIDUE REVIEWS 1980; 73:49-86. [PMID: 6154957 DOI: 10.1007/978-1-4612-6068-4_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
23
|
Lutz WK. In vivo covalent binding of organic chemicals to DNA as a quantitative indicator in the process of chemical carcinogenesis. Mutat Res 1979; 65:289-356. [PMID: 390383 DOI: 10.1016/0165-1110(79)90006-x] [Citation(s) in RCA: 340] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The covalent binding of chemical carcinogens to DNA of mammalian organs is expressed per unit dose, and a 'Covalent-Binding Index', CBI, is defined. CBI for various carcinogens span over 6 orders of magnitude. A similar range is observed for the carcinogenic potency in long-term bioassays on carcinogenicity. For the assessment of a risk from exposure to a carcinogen, the total DNA dmaage can be estimated if the actual dose is also accounted for. A detailed description is given for planning and performing a DNA-binding assay. A complete literature survey on DNA binding in vivo (83 compounds) is given with a calculation of CBI, where possible, 153 compounds are listed where a covalent binding to any biological macromolecule has been shown in vivo or in vitro. Recent, so far unpublished findings with aflatoxin M1, macromolecule-bound aflatoxin B1, diethylstilbestrol, and 1,2-epithiobutyronitrile are included. A comparison of CBI for rat-liver DNA with hepatocarcinogenic potency reveals a surprisingly good quantitative correlation. Refinements for a DNA-binding assay are proposed. Possibilites and limitations in the use of DNA binding in chemical carcinogenesis are discussed extensively.
Collapse
|
24
|
Abstract
The chemical structure, reactivity and metabolic fate of the insecticide dichlorvos (2,2-dichlorovinyl dimethyl phosphate) are discussed in relation to the possible genotoxicity of this and other methyl phosphate triesters. Recent attempts to demonstrate the methylation of DNA following exposure of bacteria and animals to dichlorvos are reviewed. On the basis of comparative data relating mutagenesis to methylation reactions, it seems entirely appropriate to conclude that the mutagenicity of dichlorvos to bacteria is due solely to methylation of the bacterial DNA under the conditions of these tests. However, the methylation of mammalian DNA could not be demonstrated under realistic exposure conditions (when the alkylating mutagen methyl methanesulphonate afforded clearly measurable methylation). The failure to detect methylation by dichlorvos in vivo is attributed to the operation of highly efficient enzyme-catalysed biotransformations which rely largely on the phosphorylating reactivity of dichlorvos. The biotransformation pathways, characterised mostly in the rat, appear to be common also to pig, mouse, hamster, and man.
Collapse
|
25
|
Wooder MF, Wright AS, King LJ. In vivo alkylation studies with dichlorvos at practical use concentrations. Chem Biol Interact 1977; 19:25-46. [PMID: 922973 DOI: 10.1016/0009-2797(77)90040-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Twenty male CFE rats were exposed to atmospheres containing 0.064 microgram/l of [Me-14C] dichlorvos (113 Ci/mol) for 12 h. Analysis of the DNA and RNA from the total soft tissues of these rats revealed no methylation of the N7 atom of guanine moieties. The limits of detection of methylation were one methyl group per 6.0 X 10(11) and per 2 X 10(9) nucleotide units for DNA and RNA, respectively. Only 0.000001% of the administered dose would have needed to react with DNA in order to produce detectable methylation of this macromolecule. The exposure period employed in this study (12 h) constituted a significant fraction of the half-life of 7-methylguanine moieties in DNA (3 days). On the basis of this information and the extremely rapid metabolism of dichlorvos in a wide range of mammalian tissues and species it was concluded that dichlorvos does not methylate the nucleic acids of mammalian tissues when it is inhaled continuously at practical use concentrations.
Collapse
|
26
|
Magee PN. Extrapolation of cellular and molecular level studies to the human situation. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1977; 2:1415-24. [PMID: 328924 DOI: 10.1080/15287397709529540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
27
|
Shooter KV. Assays for phosphotriester formation in the reaction of bacteriophage R17 with a group of alkylating agents. Chem Biol Interact 1975; 11:575-88. [PMID: 172245 DOI: 10.1016/0009-2797(75)90032-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The interaction of bacteriophage R17 with 8 compounds has been studied, comparing the contribution of degradation of ribonucleic acid to the total toxicity. Breaks in the RNA chain result from the hydrolysis of phosphotriesters and thus are a measure of the extent of O-alkylation and of the SN1-type mechanism of the reaction. With many alkylating agents mutagenicity and carcinogenicity increase with increasing SN1 character of the reaction. In experiments with methyl methanesulphonate no evidence of degradation was observed at up to 19 times the mean lethal dose (620 methylations/RNA molecule). Breaks in the RNA chain accounted for 1 in 10 of the lethal lesions with beta-hydroxyethyl methanesulphonate, 1 in 60 with bis-(2-chloromethyl)methylamine (nitrogen mustard, HN2), less than 1 in 125 with 2,2-dichlorvinyl dimethyl phosphate (dichlorovos, DDVP), and 1 in 200 with propylene oxide. The hydrolysis rate of bis-(2 chloroethyl)ether was too slow for any reaction to be detected. In reactions with the carcinogen bis-(2-chloromethyl)ether the toxicity observed could be accounted for by the formaldehyde produced on hydrolysis. Cross-linking of the bacteriophage components by formaldehyde reduced the survival range over which the physical state of the RNA could be studied. No evidence of RNA degradation was observed. Reaction of the formaldehyde led to a progressive loss of biological activity over 24 h, a loss which was partially reversed by dialysis.
Collapse
|
28
|
Frei JV, Lawley PD. Methylation of DNA in various organs of C57B1 mice by a carcinogenic dose of N-methyl-N-nitrosourea and stabiltty of some methylation products up to 18 hours. Chem Biol Interact 1975; 10:413-27. [PMID: 1149172 DOI: 10.1016/0009-2797(75)90072-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Female 6-8-week-old (57B1 mice were injected i.p. with N-methyl-N-nitrosourea (MNUS) (14C or 3H-methyl-labelled) in saline (80 mg/kg) and DNA was isolated from bone marrow, small bowel, kidneys, liver, lungs, spleen and thymus at various times thereafter up to 18 h. Methylation of DNA was found in all organs examined, and by analyses using column or paper chromatography of DNA hydrolysates, the extent of methylation of DNA purines was determined. Methylated guanine residues (at N-3, N-7 and 0-6 positions) were stable in DNA up to 18 h, but methylated adenines (at N-3 or N-7) were removed from DNA of all organs examined; the overall half-life of methyladenines was about 3 h, but removal appeared to occur in a biphasic manner, with a proportion of methyladenine remaining relatively stable. This relative stability was somewhat more marked in bone marrow than in other organs.
Collapse
|
29
|
|
30
|
Green MH, Medcalf AS, Arlett CF, Harcourt SA, Lehmann AR. DNA strand breakage caused by dichlorvos, methyl methanesulphonate and iodoacetamide in Escherichia coli and cultured Chinese hamster cells. Mutat Res 1974; 24:365-78. [PMID: 4369937 DOI: 10.1016/0027-5107(74)90181-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
31
|
|