Biomaterial Database

Marked effect of buffers on yield of single- and double-strand breaks in DNA irradiated at room temperature and at 77 K. 1993

P M Cullis, and D Elsy, and S Fan, and M C Symons

Chemistry Department, The University, Leicester, UK.

We have shown that the protocol for handling plasmid (pBR 322) DNA for radiation studies, which normally involves using quite high concentrations of Tris or phosphate buffers, is equally satisfactory in the absence of added buffers provided samples are stored at 0 degree C, or used directly. On exposure of aqueous solutions at 77 K, Tris buffer acts as a weak protecting agent, but phosphate buffers at the same pH act as remarkably effective sensitizing agents, giving ca. 100-fold increases in strand breaks. At room temperature there is again a marked difference between the aqueous and buffered systems, but in this case both the Tris and the phosphate systems are protective. Possible reasons for these contrasting results are discussed, and the advantages of using simple aqueous solutions are stressed.

UI	MeSH Term	Description	Entries
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D011831	Radiation Genetics	A subdiscipline of genetics that studies RADIATION EFFECTS on the components and processes of biological inheritance.	Genetics, Radiation
D011837	Radiation-Protective Agents	Drugs used to protect against ionizing radiation. They are usually of interest for use in radiation therapy but have been considered for other purposes, e.g. military.	Radiation Protectant,Radiation Protective Agent,Radiation-Protective Agent,Radiation-Protective Drug,Radioprotective Agent,Radioprotective Agents,Radioprotective Drug,Agents, Radiation-Protective,Radiation Protectants,Radiation Protective Agents,Radiation-Protective Drugs,Radiation-Protective Effect,Radiation-Protective Effects,Radioprotective Drugs,Agent, Radiation Protective,Agent, Radiation-Protective,Agent, Radioprotective,Agents, Radiation Protective,Agents, Radioprotective,Drug, Radiation-Protective,Drug, Radioprotective,Drugs, Radiation-Protective,Drugs, Radioprotective,Effect, Radiation-Protective,Effects, Radiation-Protective,Protectant, Radiation,Protectants, Radiation,Protective Agent, Radiation,Protective Agents, Radiation,Radiation Protective Drug,Radiation Protective Drugs,Radiation Protective Effect,Radiation Protective Effects
D011838	Radiation-Sensitizing Agents	Drugs used to potentiate the effectiveness of radiation therapy in destroying unwanted cells.	Radiation Sensitizer,Radiosensitizing Agent,Radiosensitizing Agents,Agents, Radiation-Sensitizing,Radiation Sensitizers,Radiation Sensitizing Agents,Radiation-Sensitizing Drugs,Radiation-Sensitizing Effect,Radiation-Sensitizing Effects,Radiosensitizing Drugs,Radiosensitizing Effect,Radiosensitizing Effects,Agent, Radiosensitizing,Agents, Radiation Sensitizing,Agents, Radiosensitizing,Drugs, Radiation-Sensitizing,Drugs, Radiosensitizing,Effect, Radiation-Sensitizing,Effect, Radiosensitizing,Effects, Radiation-Sensitizing,Effects, Radiosensitizing,Radiation Sensitizing Drugs,Radiation Sensitizing Effect,Radiation Sensitizing Effects,Sensitizer, Radiation,Sensitizers, Radiation,Sensitizing Agents, Radiation
D002021	Buffers	A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.	Buffer
D004249	DNA Damage	Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.	DNA Injury,DNA Lesion,DNA Lesions,Genotoxic Stress,Stress, Genotoxic,Injury, DNA,DNA Injuries
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004277	DNA, Single-Stranded	A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.	Single-Stranded DNA,DNA, Single Stranded,Single Stranded DNA
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures