Repair of rat liver DNA in vivo damaged by ethylene dibromide

Nachtomi, Edna; Sarma, D.S.R.

doi:10.1016/0006-2952(77)90170-8

Cited by 39 publications

(8 citation statements)

References 23 publications

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“…It has been suggested that both DBE and DBM could react as alkylating agents [8,9,14]. However, preinduction of the adaptive response by exposure to a low concentration of a methylating agent did not decrease, but rather increased (by a factor of two), the mutagenicity of DBE in Escherichia coli [8].…”

Section: Introductionmentioning

confidence: 97%

ogt alkyltransferase enhances dibromoalkane mutagenicity in excision repair–deficient escherichia coli K‐12

Abril

Luque-Romero

Prieto‐Álamo

et al. 1995

Molecular Carcinogenesis

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We examined the role of the O6-alkylguanine-DNA alkyltransferase encoded by ogt gene in the sensitivity of Escherichia coli to the mutagenic effects of the dibromoalkanes, dibromoethane and dibromomethane, by comparing responses in ogt- bacteria to those in their isogenic ogt+ parental counterparts. The effects of the uvrABC excision-repair system, the adaptive response, mucAB and umuDC mutagenic processing, and glutathione bioactivation on the differential responses of ogt- and ogt+ bacteria were also studied. Mutation induction was monitored by measuring the frequency of forward mutations to L-arabinose resistance. Induced mutations occurred only in excision repair-defective strains and were totally (with dibromomethane) or substantially (with dibromoethane) dependent on the alkyltransferase (ATase) encoded by the ogt gene. An increased mutagenic response to both dibromoalkanes was also seen in ogt- bacteria that overexpressed the ogt protein from a multicopy plasmid, indicating that the differences in mutability between ogt+ and ogt- bacteria were not dependent on the ogt- null allele carried by the defective strain. The ATase encoded by the constitutive ogt gene was more effective in promoting dibromoalkane mutagenicity than the ada ATase induced by exposure to low doses of a methylating agent. The mutagenicity promoted by the ogt ATase was dependent on both glutathione bioactivation and SOS mutagenic processing. To our knowledge, this paper presents for the first time evidence that DNA ATases, in particular the ATase encoded by the ogt gene, can increase the mutagenic effects of a DNA-damaging agent. The mechanism of this effect has yet to be established.

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Section: Introductionmentioning

confidence: 97%

ogt alkyltransferase enhances dibromoalkane mutagenicity in excision repair–deficient escherichia coli K‐12

Abril

Luque-Romero

Prieto‐Álamo

et al. 1995

Molecular Carcinogenesis

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“…Both these proteins are rich in cysteine and are cross-linked in the chromatin. In addition, during the late phase of spermatid elongation, an unmasking of D N A takes place due to removal of all histones before being replaced by BNSP (Loir & Hochereau de 167 12* Reviers 1972), and the possibility of a direct alkylating effect of EDB on sperm DNA, as reported for the liver D N A of EDB-treated rats (Nachtomi et al 1977), cannot be excluded. Germ cells with abnormally condensed chromatin, which can result in partial loss of the unstable protein and unprotected DNA, will issue from this disturbance.…”

Section: Discussionmentioning

confidence: 99%

“…Germ cells with abnormally condensed chromatin, which can result in partial loss of the unstable protein and unprotected DNA, will issue from this disturbance. In addition, during the late phase of spermatid elongation, an unmasking of D N A takes place due to removal of all histones before being replaced by BNSP (Loir & Hochereau de Reviers 1972), and the possibility of a direct alkylating effect of EDB on sperm DNA, as reported for the liver D N A of EDB-treated rats (Nachtomi et al 1977), cannot be excluded.…”

Section: Discussionmentioning

confidence: 99%

Changes Induced to Bull Spermatids and Testicular Spermatozoa by a Single Peritesticular Injection of Ethylene Dibromide

1979

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“…All chemicals were given by gavage: DBE in 2.5 ml corn oil (MazolaR)/kg, AAF in 2.0 ml/kg of 1% carboxymethyl cellulose/kg, and CC14 as a 1 : 1 solution with corn oil in a final volume of 4 ml/kg. The 75 mg/kg dose of DBE was previously shown to alkylate and break liver DNA (Nachtomi and Sarma 1977) and to have an initiating effect in a long-term bioassay (Moslen 1984 (Nachtomi and Sarma 1977). AAF was given by gavage rather than the previously used diet (Tsuda et al 1982), due to difficulties in obtaining the diet.…”

Section: Methodsmentioning

confidence: 99%

1,2-Dibromoethane initiation of hepatic nodules in Sprague-Dawley rats selected with Solt-Farber system

1985

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Initiating effects of the fumigant 1,2-dibromoethane (DBE) for liver were examined using the Solt-Farber selection system. Male Sprague Dawley rats (230-260 g) were given one oral dose of DBE (75 mg/kg), a two-thirds partial hepatectomy 4 h later, five oral doses of 2-acetylamidofluorene (AAF) (25 mg/kg) on days 17-21, CCl4 (2 ml/kg) on day 22, a booster dose of AAF (10 mg/kg) on day 32, and were sacrificed on day 82. Nodules and appreciable gamma-glutamyl transpeptidase foci were found in the livers of four of six animals given DBE, but not in any animals of the control group.

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Repair of rat liver DNA in vivo damaged by ethylene dibromide

Cited by 39 publications

References 23 publications

ogt alkyltransferase enhances dibromoalkane mutagenicity in excision repair–deficient escherichia coli K‐12

ogt alkyltransferase enhances dibromoalkane mutagenicity in excision repair–deficient escherichia coli K‐12

Changes Induced to Bull Spermatids and Testicular Spermatozoa by a Single Peritesticular Injection of Ethylene Dibromide

1,2-Dibromoethane initiation of hepatic nodules in Sprague-Dawley rats selected with Solt-Farber system

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