title: Chironomus ramosus larvae exhibit DNA damage control in response to gamma radiation.
abstract: OBJECTIVE
  Chironomus ramosus is one of the recently reported radiotolerant insects. Salivary gland cells of fourth instar larvae respond to ionizing radiations with increases in the levels of antioxidant enzymes and chaperone proteins. Here we made an attempt to study the state of nuclear DNA after exposure of larvae to a lethal dose for 20% of the population (LD(20)) of gamma radiation (2200 Gy, at a dose rate 5.5 Gy/min).
  
  
  METHODS
  Genomic DNA preparations were subjected to competitive ELISA (Enzyme linked immunosorbent assay) for detection of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and dynamic light scattering (DLS) to monitor any radiation-induced damage. Single salivary gland cells were subjected to alkaline single cell gel electrophoresis (ASCGE), comet assay and pulsed field gel electrophoresis (PFGE) to check for DNA double-strand breaks.
  
  
  RESULTS
  Results from all four experimental procedures confirmed damage of nucleobases and fragmentation of nuclear DNA immediately after radiation. Some 48 h after radiation exposure, modified 8-oxodG residues returned to basal level, homodispersity of genomic DNA reappeared, the length of comet tail regressed significantly (ASCGE) and PFGE pattern matched with that of high molecular weight unirradiated DNA.
  
  
  CONCLUSIONS
  Chironomus ramosus larvae showed control of DNA damage as observed over 48 h in post irradiation recovery which could be attributed to their ability to tolerate gamma radiation stress.
authors.affiliation: a Department of Zoology , Savitribai Phule Pune University , Pune , India.
authors.forename: Kailas D
authors.initials: KD
authors.lastname: Datkhile
authors.affiliation: a Department of Zoology , Savitribai Phule Pune University , Pune , India.
authors.forename: Pallavi S
authors.initials: PS
authors.lastname: Gaikwad
authors.affiliation: a Department of Zoology , Savitribai Phule Pune University , Pune , India.
authors.forename: Saroj S
authors.initials: SS
authors.lastname: Ghaskadbi
authors.affiliation: b Molecular Biology Division, Bhabha Atomic Research Centre , Trombay, Mumbai , India.
authors.forename: Rita
authors.initials: R
authors.lastname: Mukhopadhyaya
authors.affiliation: a Department of Zoology , Savitribai Phule Pune University , Pune , India.
authors.forename: Bimalendu B
authors.initials: BB
authors.lastname: Nath
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D002683:Chironomidae / Q000166:cytology / Q000528:radiation effects*; D020552:Comet Assay; D004247:DNA / Q000528:radiation effects; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D053938:DNA Fragmentation; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D000067493:Dynamic Light Scattering; D005720:Gamma Rays / Q000009:adverse effects*; D007814:Larva / Q000528:radiation effects; D011836:Radiation Tolerance; D012469:Salivary Glands / Q000166:cytology / Q000528:radiation effects
chemical_list: D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D003849:Deoxyguanosine
keywords: Chironomus ramosus; DNA damage response; Pulsed field gel electrophoresis; alkaline comet assay; dynamic light scattering; gamma radiation stress