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Excision repair of bulky lesions in the DNA of mammalian cells

Description: The report examines the process of excision repair of pyrimidine dimers from uv-irradiated and chemically challenged human cells. It is shown by means of a sensitive endonuclease assay that the amount of excision observed depends upon the isotope used to label cells, and that XP heterozygotes are between normals and XPs. (ACR)
Date: January 1, 1980
Creator: Setlow, R B & Grist, E
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Three year progress report and renewal request

Description: A review of research accomplisments during the contract period is presented. Reported projects include: (1) metals as radiation sensitizers of spores; (2) studies on transforming and calf thymus DNA; (3) pulse radiolysis studies on DNA components; (4) studies of metal complexes of DNA compounds; and (5) dosimetry of the pulsed electron beam. (ACR)
Date: August 1, 1980
Creator: Powers, E. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

DNA repair in human cells exposed to combinations of carcinogenic agents

Description: Normal human and XP/sup 2/ fibroblasts were treated with uv plus uv-mimetic chemicals. The uv dose used was sufficient to saturate the uv excision repair system. Excision repair after combined treatments was estimated by unscheduled DNA synthesis, BrdUrd photolysis, and the loss of sites sensitive to a uv specific endonuclease. Since the repair of damage from uv and its mimetics is coordinately controlled we expected that there would be similar rate-limiting steps in the repair of uv and chemic… more
Date: January 1, 1980
Creator: Setlow, R.B. & Ahmed, F.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Movable Genetic Elements: Detection of Changes in Maize DNA at the Shrunken Locus Due to the Intervention of Ds Elements

Description: This report describes our initial attempts at the molecular characterization of a maize controlling element. We have prepared a cDNA probe and used it to detect changes at a locus where Ds elements are found. Evidence of their presence are indicated by changes in the restriction patterns, but there is as yet no information on the physical nature of the controlling elements nor on the kinds of rearrangements they cause.
Date: May 28, 1980
Creator: Burr, B. & Burr, F.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Comprehensive progress report, 1977-1980

Description: Research accomplishments and activities during the past three year period are described. Specific projects were: (1) restriction endonuclease studies of tetrahymena mtDNA; (2) biosynthesis of mitochondrial tRNA; and (3) structure and synthesis of tRNA charging enzymes. (ACR)
Date: January 1, 1980
Creator: Suyama, Y
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

DNA damage and carcinogenesis

Description: Although cancer may arise as a result of many different types of molecular changes, there is little reason to doubt that changes to DNA are one of the more important ones in cancer initiation. Although DNA repair mechanisms seem able to eliminate a very large fraction of deleterious changes to DNA, we not only have little insight into the molecular mechanisms involved in such repair, but have a negligible amount of information to permit us to estimate the shape of dose response relations at low… more
Date: January 1, 1980
Creator: Stelow, R B
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Haemophilus influenzae does not fit theories of postreplication repair

Description: Studies with Escherichia coli have provided all the initial insights into the molecular bases of repair processes. It is the thesis of this article that especially if we believe that there are some general mechanisms in nature, it is important to consider more than one microorganism in arriving at an understanding of the biology of repair of DNA.
Date: January 1, 1980
Creator: Setlow, J K & Notani, N K
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

DNA replication and the repair of DNA strand breaks in nuclei of Physarum polycephalum. Terminal report, August 1, 1978-March 31, 1980

Description: Nuclei isolated from Physarum are able to replicate approximately 15% of the total genome in a manner which is qualitatively similar to the DNA replication process occurring in the intact organism. Such nuclei, however, are defective in the joining of Okazaki intermediates in vitro. Two DNA polymerase species, isolated from nuclei or intact plasmodia of this organism, can be separated by sucrose density gradient centrifugation. Total DNA polymerase activity is low in nuclei isolated during mito… more
Date: January 1, 1980
Creator: Brewer, E. N. & Evans, T. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Biological effects of ionizing radiation at the molecular, cellular, and organismal levels. Triennial progress report, October 15, 1977-October 14, 1980

Description: Two major accomplishments have been achieved in the past three years with the support of this contract. Firstly, the original Zimm theory of rotor speed dependent DNA sedimentation has been tested quantitatively and found to be correct, i.e., T4c and T4D+ DNAs sedimented with S/sup 0//sub 20,w/ values as predicted by the equation of Zimm and Schumaker. Furthermore, the quantitative validity of the theory means that the size (M/sub r/) of a DNA sedimenting under speed-dependent conditions is not… more
Date: January 1, 1980
Creator: Lange, C.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Differential gene expression in neurospora crassa cell types: amplification of rRNA genes. Progress report, July 1979-30 June 1980

Description: The significant results obtained during 1979 to 1980 of the current research program are as follows: (1) the differential rRNA gene amplification in germinated conidia of N.crassa was confirmed. N.crassa rDNAs showed differences in degrees of homology with isolated DNAs from other Neurospora species which could be due to heterogeneity in internal spacers. Studies with N.crassa rDNA clones were initiated to study their heterogeneities. The organization of the Institutional Biohazard Committee (I… more
Date: January 1, 1980
Creator: Dutta, S.K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Quantification of Poly(ADP-ribose) in Normal and in DNA-Damaged Cells

Description: This work presents the development of a new highly sensitive and selective chemical assay for poly(ADP-ribose) which is routinely useful for the determination of polymer levels in vivo. This method was used to carefully measure poly(ADP-ribose) levels in normal and in DNA-damaged cells. The results of these studies strongly suggest that synthesis of poly(ADP-ribose) is involved in some aspect of DNA repair. A review of the literature is presented in the introduction of this work. Poly(ADP-ribo… more
Date: December 1980
Creator: Sims, James L.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Repair of DNA treated with. gamma. -irradiation and chemical carcinogens. Progress report, March 15, 1979-March 15, 1980

Description: The identification and purification of 3-methyladenine glycosylase from the cell nuclei of rat liver was completed. The characterization of 7-methylguanine N-glycosylase activity in E. coli is currently under investigation. Alkylated DNA in chromatin structures as a substrate for 3-methyladenine N-glycosylase is discussed. An enzyme from E. coli and mammalian tissue active on 2,6-diamino-4-hydroxy-5-N-methyldormamido-pyrimide is isolated and characterized. Studies are proceeding on the correlat… more
Date: January 1, 1980
Creator: Goldthwait, D.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Photoreactivation in bacteria and in skin

Description: In many procaryotic and eucaryotic cells, photoreactivating enzyme mediates light-dependent repair of uv-induced damage; the enzyme binds to a pyrimidine dimer in DNA, and, on absorption of a photon (300 to 600 nm), specifically monomerizes the dimer, thus repairing the DNA. Photoreactivating enzyme has been found in human tissues and human cells in culture can photoreactivate cellular dimers, and can mediate photoreactivation of Herpes (human fibroblasts) and Epstein-Barr virus (human leukocyt… more
Date: January 1, 1980
Creator: Sutherland, B. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Relationship of DNA Repair Processes to Mutagenesis and Carcinogenesis in Mammalian Cells. Progress Report, August 1, 1977-October 31, 1980

Description: The objective of this research is to determine the role of DNA repair in mutagenesis and carcinogenesis in mammalian cells. More specifically, mutant strains will be selected which are deficient in various DNA repair pathways. These strains will be studied with regard to (1) the nature of the defect in repair, and (2) the mutability and transformability of the defective cells by various agents as compared to the wild type parental cells. The results to date include progress in the following are… more
Date: October 1, 1980
Creator: Evans, H. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Simplified method for DNA and protein staining of human hematopoietic cell samples

Description: A rapid reproducible method yielding high resolution analysis of DNA and protein in human hematopoietic cell samples was developed by modification of the propidium iodide (PI) and fluorescein isothiocyanate (FITC) procedure. Cell staining involved sequential addition of each reagent (RNase, FITC, and PI) to ethanol-fixed cells and requires no centrifiguation steps. Stained cells are analyzed in the reagent solutions. Analysis of bone marrow samples from multiple myeloma patients revealed mixed … more
Date: January 1, 1980
Creator: Crissman, H. A.; Egmond, J. V.; Holdrinet, R. S.; Pennings, A. & Haanen, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Relationship of DNA Repair Processes to Mutagenesis and Carcinogenesis in Mammalian Cells. Progress Report, November 1, 1979-October 31, 1980

Description: The objective of this research is to determine the role of DNA repair in mutagenesis and carcinogenesis in mammalian cells. Use of the host-cell reactivation viral suicide enrichment procedure was initiated in the isolation of repair-deficient mutants. Lightly mutagenized BHK cells were infected with irradiated Herpes simplex virus (HSV); several radiation-sensitive strains were isolated among the survivors of the infection. The characterization of these strains is progressing and the enrichmen… more
Date: October 1, 1980
Creator: Evans, H. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Inducible error-prone repair in B. subtilis. Progress report, September 1, 1979-February 28, 1981

Description: The mechanism of activation and the mode of action of the SOS system in Bacillus subtilis are being investigated. Interesting aspects of the SOS system in B. subtilis include: (1) the differences between the SOS functions in this bacterium and in the enteric bacteria; (2) the spontaneous activation of SOS functions in competent cells; and (3) the difficulty in establishing the presence of error-prone repair in this bacterium. In order to characterize the SOS system of B. subtilis, attempts will… more
Date: October 1, 1980
Creator: Yasbin, R E
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Modeling the dose-response relationship for cytotoxicity of human cells exposed to chemical carcinogens. [N-acetoxy-2-acetylaminofluorene]

Description: Compounds like N-acetoxy-2-acetylaminofluorene (N-AcO-AAF) result from the in vivo reduction of nitrate derivatives of benzo(..cap alpha..)pyrene. The dose-response relationship for survival of cloning ability in human fibroblasts exposed to N-AcO-AAF is being investigated to obtain a better understanding of the carcinogenic potential of coal-related air pollutants. A model is presented which correlates the survival of normal human fibroblasts after exposure to N-AcO-AAF with the rate of excisi… more
Date: September 1, 1980
Creator: Miller, J.H. & Heflich, R.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

MODULATION BY IONIC STRENGTH AND SUPERHELICITY OF BENZO[a]PYRENE DIOL EPOXIDE INDUCED DNA ALKYLATION AND UNWINDING

Description: Superhelical and partially relaxed SV40 DNA were reacted in vitro with (+)7{beta}, 8{alpha}-dihydroxy-9{alpha},10{alpha}-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BaP diol epoxide). The modified DNA contained N{sup 2} guanine and N{sup 6} adeninte hydrocarbon adducts in the ratio 86:14. Superhelical SV40 DNA was approximately 6% more susceptible to modification than partially relaxed viral DNA. Counterions inhibited DNA alkylation by up to 90%, Mg{sup 2+} being 50-fold more effective than Na{sup… more
Date: January 1, 1980
Creator: Gamper, Howard B.; Straub, Kenneth; Calvin, Melvin & Bartholomew, James C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Benzo[a]Pyrene Diol Epoxide Perturbation of Cell Cycle Kinetics of Synchronized Mouse Liver Epithelial Cells

Description: A cell cycle synchronization system is described for the analysis of the perturbation of cell cycle kinetics and the cycle-phase specificity of chemicals and other agents. We used the system to study the effects of ({+-})r-7, t-8-dihydroxy-t-9, 10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BaP diol epoxide) upon the cell cycle of mouse liver epithelial cells(NMuLi). BaP diol epoxide(0.6 uM) was added to replated cultures of NMuLi cells that had been synchronized in various stages of the cell cycle … more
Date: July 1, 1980
Creator: Pearlman, A. L.; Navsky, B. N. & Bartholomew, J. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

PROTEOLYTIC REMOVAL OF THE CARBOXYL TERMINUS OF THE T4 GENE 32 HELIX-DESTABILIZING PROTEIN ALTERS THE T4 IN VITRO REPLICATION COMPLEX

Description: The proteolytic removal of about 60 amino acids from the COOH terminus of the bacteriophage T4 helix-destabilizing protein (gene 32 protein) produces 32*I, a 27,000-dalton fragment which still binds tightly and cooperatively to single-stranded DNA. The substitution of 32*I protein for intact 32 protein in the seven-protein T4 replication complex results in dramatic changes in some of the reactions catalyzed by this in vitro DNA replication system, while leaving others largely unperturbed. (1) L… more
Date: July 1, 1980
Creator: Burke, R.L.; Alberts, B.M. & Hosoda, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Mechanisms of recombination and function of DNA in bacteria. Progress report, August 16, 1979 to August 15, 1980

Description: Major effort in this period has gone to (1) analysis of the process of plasmid transformation in pneumococcus, (2) continued study of resistance determinants inserted in the chromosomes of clinical strains of pneumococcus and their transfer by conjugation, a novel phenomenon, discovered last year, and (3) temperate phages of pneumococcus.
Date: January 1, 1980
Creator: Guild, W. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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