PubMed Health⌕ Search

Biomedical subjects

M Dizdaroglu

Publications and source records attributed to M Dizdaroglu.

125 records · Page 7Linked to original sources
PubMed1983

Isolation and characterization of radiation-induced aliphatic peptide dimers.

alpha-Peptide radicals of L-Ala-L-Ala and tetra-L-Ala, formed from reaction with OH radicals, generated in H2O by ionizing radiation, were shown to give peptide dimers. These peptide dimers were separated and isolated by HPLC. On acid hydrolysis, all of the studied peptide dimers yielded alanine and 1,2-diamino-1,2-dimethyl succinic acid, which was characterized by gas chromatography-mass spectrometry as its TMS derivative. The described procedure is also suggested as a suitable method for isolation and characterization of amino acid dimers.

Cobalt Radioisotopes↗
PubMed1980

Separation and sequencing of the sequence isomers of pyrimidine deoxypentanucleoside tetraphosphates by high-performance liquid chromatography.

Chemical synthesis of DNA fragments with a defined sequence is extremely long and complex. A simpler alternative is isolation of fragments from partially hydrolysed DNA. Mixtures of sequence isomers of pyrimidine oligonucleotides were recently isolated on a preparative scale from hydrolysates of depurinated herring sperm DNA. These, however, could not be further separated by conventional techniques. Using high-performance liquid chromatography (HPLC), sequence isomers of pyrimidine di-, tri- and tetranucleotides were successfully separated and sequenced. In the present work, separation and sequencing of sequence isomers of pyrimidine pentanucleotides by HPLC was achieved, demonstrating the applicability of this particular approach in preparation of desired DNA fragments.

Animals↗
PubMed1979

Separation of small DNA and RNA oligonucleotides by high-performance anion-exchange liquid chromatography.

Small oligonucleotides from DNA and RNA have been separated according to their base composition by high-performance anion-exchange liquid chromatography on Partisil-10 SAX using triethylammonium acetate buffer as the eluent. Fifteen of the 16 possible deoxydinucleoside monophosphates and all 16 dinucleoside monophosphates have been separated. All pairs of sequence isomers were all resolved. The 15 commercially available deoxydinucleotides were resolved into 13 fractions. A good resolution of deoxytrinucleoside diphosphates isolated from an alkaline phosphatase-Mg2+-activated DNase I digest of calf thymus DNA was achieved by this technique. A large number of sequence isomers could be fully separated. The base sequence of the eluted individual constituents has been determined by their hydrolysis with snake venom and spleen phosphodiesterase followed by high-performance liquid chromatographic analysis of the nucleotides released. The eight trinucleoside diphosphates isolated from an alkaline phosphatase-pancreatic RNase digest of yeast RNA have also been separated according to base composition. Their sequence was determined as above. The described technique is fast and gave very good separation. Most of the sequence isomers could be separated. Moreover, the eluent triethylammonium acetate can easily be removed from column effluents by freeze-drying in order to facilitate subsequent sequence analysis of the eluted compounds. The observed elution orders of the sequence isomers obey certain rules which are discussed in detail.

Animals↗
PubMed1979

Radiation-induced DNA strand breaks in deoxygenated aqueous solutions. The formation of altered sugars as end groups.

Gamma irradiation of DNA in deoxygenated, N2O-saturated aqueous solution leads to three bound altered sugars present as end groups in broken DNA strands. These sugars are linked to the DNA by phosphoric acid ester bonds. Two of the end groups have the structures (4) and (5). (Formula: see text) The third end group after dephosphorylation has structure (3). The formation of the bound sugars (4) and (5) is explained by a mechanism postulated earlier for the formation of free altered sugars. Except for the phosphoric acid ester linkage, the free altered sugars have the same chemical structures as the bound altered sugars.

Chemical Phenomena↗
PubMed1978

Enzymatic digestion of DNA gamma-irradiated in aqueous solution separation of the digests by ion-exchange chromatography.

Aqueous solutions of DNA were gamma-irradiated in the presence and absence of oxygen and enzymatically hydrolysed by the combined action of pancreatic deoxyribonuclease (DNase I), snake-venom phosphodiesterase (PDE I), spleen phosphodiesterase (PDE II) and alkaline phosphatase. In contrast to unirradiated DNA, which is fully hydrolysed to nucleosides by these enzymes, gamma-irradiated DNA yields a series of oligonucleotides. Their isolation might enalbe the future identification of the chemical nature of DNA lesions.

Alkaline Phosphatase↗
PubMedDate not supplied

Nickel(II)-mediated oxidative DNA base damage in renal and hepatic chromatin of pregnant rats and their fetuses. Possible relevance to carcinogenesis.

DNA base damage was studied in renal and hepatic chromatin of nickel(II)-injected pregnant female F344/NCr rats and their fetuses under conditions leading to initiation of sodium barbital-promotable renal tumors, but not liver tumors, in the male offspring. Pregnant rats were given a total of 90 or 180 mumol of nickel(II) acetate/kg body wt in a single ip dose on day 17 or in 2 or 4 ip doses between days 12 and 18 of gestation. Control rats received 180 mumol of sodium acetate/kg body wt. The animals were killed 24 or 48 h after the last injection. Chromatin was isolated from livers and kidneys from both adults and fetuses and analyzed by gas chromatography/mass spectrometry with selected ion monitoring. Eleven products derived from the purine and pyrimidine bases in DNA bases were identified and quantified. These were the following: 5-hydroxy-5-methylhydantoin, 5-hydroxyhydantoin, 5-(hydroxymethyl)uracil, cytosine glycol, thymine glycol, 5,6-dihydroxycystosine, 4,6-diamino-5-formamidopyrimidine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 8-hydroxyadenine, 2-hydroxyadenine, and 8-hydroxyguanine (8-OH-Gua). Nickel(II) exposure increased the content of these products, especially those derived from purines, in both renal and hepatic chromatin of pregnant rats. The major difference between these two organs was the content of 8-OH-Gua, which increased greatly in the kidney but remained unchanged in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Enhancement by L-histidine of nickel(II)-induced DNA-protein cross-linking and oxidative DNA base damage in the rat kidney.

Formation of DNA-protein cross-links and oxidatively damaged DNA bases was investigated with the use of alkaline elution and gas chromatography/mass spectrometry techniques in the nuclei from kidneys of rats 3 and 18 h after a single iv injection of the NiII(His)2 complex (NiHis), nickel(II) acetate (NiAcet), or L-histidine (His). Administration of 20 mumol of NiHis/kg body wt caused the formation of DNA-protein cross-links and significantly increased levels of oxidatively damaged DNA bases, including 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua; 3.5-fold vs the control value) 3 h postinjection and 8-oxoguanine (2.6-fold), cytosine glycol (2.5-fold), 8-oxoadenine (2-fold), and FapyGua (1.9-fold) 18 h postinjection. Injection of 20 mumol of NiAcet/kg body wt enhanced the cross-linking to a lesser extent than NiHis and did not significantly increase the amounts of modified DNA bases over the control levels. Forty micromoles of His per kilogram body wt alone caused a marked DNA-protein cross-linking effect and increased the amount of 4,6-diamino-5-formamidopyrimidine (2-fold vs the control) 3 h, but not 18 h, after treatment. The DNA base derivatives found were typical products of hydroxyl radical (.OH) attack on DNA. Formation of the cross-links may also be attributed to .OH, although other mechanisms, e.g., formation of ternary complexes of Ni(II), cannot be excluded. The present in vivo study confirms the conclusion of our former in vitro experiments that His enhances Ni(II)-mediated oxidative damage to DNA and chromatin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Oxidative DNA base damage in renal, hepatic, and pulmonary chromatin of rats after intraperitoneal injection of cobalt(II) acetate.

DNA base damage was studied in renal, hepatic, and pulmonary chromatin of male and female F344/NCr rats that had been given either 50 or 100 mumol of Co(II) acetate/kg body wt in a single ip dose and killed 2 or 10 days later. Control rats received 200 mumol of sodium acetate/kg body wt. Chromatin was isolated from organs and analyzed by gas chromatography/mass spectrometry with selected ion monitoring. The following 11 products derived from purine and pyrimidine bases in DNA were quantified: 5-hydroxy-5-methylhydantoin, 5-hydroxyhydantoin,5-(hydroxymethyl)uracil(5-OHMe-Ura),5- hyd roxycytosine(5-OH- Cyt),thymine glycol, 5,6-dihydroxycytosine,4,6-diamino-5-formamido-pyrimidine (FapyAde),2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua),7,8-dihydro-8-oxoadenine,2-oxoadenine, and 7,8-dihydro-8-oxoguanine. The response was organ-specific. Eight of the DNA base products in renal chromatin of Co(II)-treated rats (mostly 5-OH-Cyt and other pyrimidine products), five in hepatic chromatin (mostly FapyGua and other purine products), and two in pulmonary chromatin (5-OHMe-Ura > FapyAde) were increased by 30% to more than 200% over control levels with increasing Co(II) dose. The renal and hepatic, but not pulmonary, DNA base damage tended to increase with time. No significant differences in response were found between male and female rats. The bases determined were typical products of hydroxyl radical attack on DNA, suggesting a role for this radical in the mechanism(s) of DNA damage caused by Co(II) in vivo. Some of these bases have been shown previously to be promutagenic. The present results imply involvement of oxidative DNA base damage in Co(II)-induced genotoxic and carcinogenic effects.

Acetates↗
PubMedDate not supplied

Radiation chemistry of DNA, II. Strand breaks and sugar release by gamma-irradiation of DNA in aqueous solution. The effect of oxygen.

From gamma-irradiated oxygenated aqueous solutions of DNA, 2-deoxy-tetrodialdose (1) and 2-deoxy-pentos-4-ulose (2) have been isolated as free sugars. The formation of 1 indicates that in the presence of oxygen the DNA strand is not only broken by mere phosphate ester cleavage but also by C--C-bond rupture in the sugar moiety. Such a process has not been encountered in deoxygenated solutions so far. The mechanism for the formation of 1 is discussed.

DNA↗
PubMedDate not supplied

gamma-Radiolyses of DNA in oxygenated aqueous solution. Structure of an alkali-labile site.

Erythritol-1-d1 has been isolated from gamma-irradiated aqueous oxygenated solution of DNA after reductions with NaBD4, alkali and phosphatase treatment. It is concluded that this product stems from a D-erythrose 2,4-diphosphate unit in the DNA which is formed via a sequence of reactions following H-abstraction at C-2' by OH radicals.

Chemical Phenomena↗