Biomaterial Database

Inhibition of induced ornithine decarboxylase activity in Chinese hamster cells by gamma radiation, far ultraviolet light and psoralen plus near-ultraviolet light: a comparative study. 1981

E Ben-Hur, and E Riklis

Inhibition by radiation of the transcriptionally controlled induction of ornithine decarboxylase (ODC) was studied in plateau-phase Chinese hamster cells. The effects of gamma radiation, far ultraviolet (254nm, UV-C) light and psoralen plus near-U.V. light (360nm, PUV-A) were compared. Increasing doses of all three treatments caused an exponential decrease in the capacity for ODC induction. This was preceded by a large shoulder region in the case of PUV-A. There was no shoulder for gamma radiation and possibly none or a small one for UV-C. When compared on the basis of cell killing UV-C is 13 times more efficient in inhibiting ODC induction than PUV-A and 69 times more than gamma radiation. The doses required to produce an inactivating hit for inhibition of ODC induction (D0) are 106 krad for gamma radiation, 2400 J m-2 for PUV-A and 14 J m-2 for UV-C. These doses produce about one gamma ray lesion, one psoralen adduct and one pyrimidine dimer in the structural gene of ODC. However, the number of lesions per transcription unit may be up to 10, depending on the contribution to the effect by lesions in transcribed and non-transcribed spacers and introns. Thus, assuming that most of the inhibition is due to effects on RNA synthesis, the various DNA lesions appear to have a similar efficiency in terminating RNA transcription, in spite of their greatly different efficiency in cell killing.

UI	MeSH Term	Description	Entries
D009955	Ornithine Decarboxylase	A pyridoxal-phosphate protein, believed to be the rate-limiting compound in the biosynthesis of polyamines. It catalyzes the decarboxylation of ornithine to form putrescine, which is then linked to a propylamine moiety of decarboxylated S-adenosylmethionine to form spermidine.	Ornithine Carboxy-lyase,Carboxy-lyase, Ornithine,Decarboxylase, Ornithine,Ornithine Carboxy lyase
D011564	Furocoumarins	Polycyclic compounds consisting of a furan ring fused with coumarin. They commonly occur in PLANTS, especially UMBELLIFERAE and RUTACEAE, as well as PSORALEA.	Furanocoumarin,Furanocoumarins,Furocoumarin,Psoralens,Angelicins
D002262	Carboxy-Lyases	Enzymes that catalyze the addition of a carboxyl group to a compound (carboxylases) or the removal of a carboxyl group from a compound (decarboxylases). EC 4.1.1.	Carboxy-Lyase,Decarboxylase,Decarboxylases,Carboxy Lyase,Carboxy Lyases
D002470	Cell Survival	The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.	Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D003037	Cobalt Radioisotopes	Unstable isotopes of cobalt that decay or disintegrate emitting radiation. Co atoms with atomic weights of 54-64, except 59, are radioactive cobalt isotopes.	Radioisotopes, Cobalt
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D004790	Enzyme Induction	An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.	Induction, Enzyme
D005720	Gamma Rays	Penetrating, high-energy electromagnetic radiation emitted from atomic nuclei during NUCLEAR DECAY. The range of wavelengths of emitted radiation is between 0.1 - 100 pm which overlaps the shorter, more energetic hard X-RAYS wavelengths. The distinction between gamma rays and X-rays is based on their radiation source.	Gamma Wave,Gamma Radiation,Nuclear X-Rays,Radiation, Gamma,X-Rays, Nuclear,Gamma Radiations,Gamma Ray,Gamma Waves,Nuclear X Rays,Nuclear X-Ray,Ray, Gamma,Wave, Gamma,Waves, Gamma,X Rays, Nuclear,X-Ray, Nuclear
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia