Linked Life Data

8378529

Source:http://linkedlifedata.com/resource/pubmed/id/8378529

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1993-10-21
pubmed:abstractText
Saccharomyces cerevisiae and Chlamydomonas reinhardtii respond to a sublethal exposure of ionizing radiation by increasing their resistance to killing by a second exposure. We demonstrate here that the two lower eukaryotes apparently achieve this by different mechanisms. We have shown that induced radioresistance in yeast results from increased capacity for recombinational repair, which we believe to occur in G2-phase haploid cells by recombination between homologous chromosomes. This is not possible in G1-phase haploid cells, which lack a second copy of DNA. Haploid C. reinhardtii cells, however, show induced resistance when irradiated asynchronously or in the G1 phase of the cell cycle. We have shown previously that the development of radiation resistance in yeast is proportional to the magnitude of the inducing dose and clearly demonstrates an oxygen effect. There was no oxygen effect for induced radiation resistance in C. reinhardtii cells, but induction remained proportional to dose. In yeast we have reported that both increased radioresistance and thermotolerance are inducible by a heat shock. Here, C. reinhardtii showed induced thermotolerance but no induced radioresistance in response to a heat stress. We have also determined previously that the induced recombinational DNA repair system in yeast recognizes alkylation lesions and therefore confers increased resistance to mutation by MNNG. In these experiments, C. reinhardtii induced for radioresistance were not more resistant to MNNG mutagenesis. These data indicate that haploid C. reinhardtii has a unique DSB repair mechanism. We propose that one possible mechanism may involve chloroplast DNA in a cooperative chloroplast/nuclear recombinational repair process.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0033-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
135
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
365-71
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
DNA repair in Chlamydomonas reinhardtii induced by heat shock and gamma radiation.
pubmed:affiliation
Atomic Energy of Canada Limited, Radiation Biology Branch, Ontario.
pubmed:publicationType
Journal Article, Comparative Study