Detection of Base Damage in DNA in Human Blood Exposed to Ionizing Radiation at Biologically Relevant Doses

Abstract

The alkaline elution technique for the detection of DNA damage has been adapted to allow application on unlabelled blood cells. Both the induction and subsequent repair have been studied of two classes of DNA damage, viz, single-strand breaks and base damage recognized by the gamma-endonuclease activity in a cell-free extract of Micrococcus luteus bacteria. The high sensitivity of the assay permitted the measurement of induction and repair of base damage after in vitro exposure of full blood under aerobic conditions to biologically relevant doses of gamma-rays (1.5-4.5 Gy). After a radiation dose of 3 Gy about 50% of the base damage was removed within 1.5 h of repair. Base damage could still be detected at 24 h after exposure to 15 Gy.

Evaluation of genotoxicity by comet assay (single-cell gel electrophoresis) in tissues of the fish Cyprinus carpio during sub-lethal exposure to Karanjin

“…Many pesticides have been proven to induce changes in DNA (Massimo, Milena, Scassellati, & Rossana, 2000;Vrhovae & Zeljezic, 2000) and structural changes at the level of chromosomes (Mathur, 1988). The physiochemical interaction of the pesticides with the cellular DNA produces a number of primary changes such as singlestrand breaks, double-strand breaks, DNA protein crosslink, and damage to purine and pyrimidine bases (Van Loon, Groenendijk, Van Der Shcanslohman, & Bran, 1991). Similar results were also reported by various investigations: Cyprinus carpio (Gowri, Govindassamy, & Ramalingam, 2013), Cirrhinus mrigala (Veeraiah, Vivek, Srinivas Rao, & Venkatrao, 2013), Channa punctatus (Thakur & Kakde, 2012), Labeo rohita (Tiwari, Tiwari, & Singh, 2012), Colisa lalia (Singh, Singh, & Yadav, 2010), Cirrhinus mrigala (Vasantharaja, Pugazhendy, Meenaambai, Prabukaran, & Dar, 2013), Channa striatus (Raksheskar, 2012), Channa punctatus (Kumar, Sharma, & Pandey, 2007), and Cyprinus carpio (Ansari & Kumar, 1988).…”

Pairing of heterochromatin in response to cellular stress

“…Moreover, MMC treatment leads to 1q11-12 homologous pairing correlating with exchanges observed for chromosome 1 homologues at metaphase (unpublished data). The various treatments are known to induce structurally different DNA lesions at very different frequencies [16,17,[23][24][25]. Taken together, data suggest that pairing of heterochromatin after exposure to various cellular stressors reflects a general stress response.…”

Effects of synthetic pyrethroids Cyfluthrin and Fenvalerate on Nucleic acid contents of fresh water fish Gambusia affinis

“…Pesticides may influence directly or modify DNA, other cellular process associated with the integrity of the genome. The pesticides interacts with the cellular DNA produces a variety of primary lesions such as single strand breaks, double strand breaks, DNA protein cross-link and damage to purine and pyrimidine bases [48].…”