Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Lethality of high linear energy transfer cosmic radiation to Escherichia coli DNA repair-deficient mutants during the ‘SL-J/FMPT’ space experiment (1998)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 164 (1998), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: We investigated the lethal and mutagenic effects of high linear energy transfer cosmic radiation on 11 strains of Escherichia coli, including DNA repair-deficient mutants, using the Radiation Monitoring Container and Dosimeter in the space shuttle ‘Endeavour’ as part of the ‘SL-J/FMPT’ space experiment, the ‘Fuwatto’ 92’ project. After the return to earth of the shuttle, we evaluated survival and mutations of samples in space and matched controls. The surviving fractions were determined by means of colony count on broth agar plates, and the mutation frequencies were estimated by appearance of arg+ revertants on minimal agar plates. The average of the total equivalent dose rate during this space flight was 0.202 mSv/day as measured by the plastic radiation detectors and the thermoluminescent dosimeters in the Radiation Monitoring Container and Dosimeter. The combined action of DNA polymerase and 3′→5′ exonuclease activities was found to make the greatest contribution to the repair of cosmic radiation-induced DNA damage, 5′→3′ exonuclease and recombination repair enzyme activities made a moderate contribution, whereas UV endonuclease activity was not involved in this DNA repair process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1998.tb13065.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The protein kinase inhibitor, H-7, suppresses heat-induced activation of heat shock transcription factor 1 (1999)
    Springer
    Molecular and cellular biochemistry 197 (1999), S. 129-135 
    Details
    ISSN: 1573-4919
    Keywords: hsp72 ; HSF ; phosphorylation ; H-7 ; protein kinase inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We investigated the effects of a protein kinase (PK) inhibitor, H-7 (1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride), on the regulation of heat shock protein (hsp)72 gene expression in a human glioblastoma cell line (A-172) using a gel mobility-shift assay and Western blot analysis. Heat shock transcription factor 1 (HSF1) was phosphorylated immediately after heat treatment (44°C, 30 min) and the phosphorylation of HSF1 was suppressed by H-7. The increase in DNA binding ability of HSF1 to heat shock element (HSE) by heat shock was significantly suppressed by the addition of H-7 in a dose-dependent manner. Similarly, the accumulation of hsp72 by heat shock was suppressed by the addition of H-7 in a dose-dependent manner. Since H-7 is known to be a potent inhibitor of some PKs, especially calcium-dependent PK (PKC), cyclicAMP-dependent PK (PKA) and cyclicGMP-dependent PK (PKG), it is possible that the activation of HSF1 by phosphorylation and subsequent hsp72 gene expression are dependent on some of those PKs. The nature of H-7 as a non-specific inhibitor for PKs is discussed in relation to its availability for regulation of heat sensitivity of cells depending on cellular level of hsp72.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006937513154
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    P53 status plays no role in radiosensitizing effects of SN-38, a camptothecin derivative (2000)
    Springer
    Cancer chemotherapy and pharmacology 45 (2000), S. 362-368 
    Details
    ISSN: 1432-0843
    Keywords: Key words SN-38 ; CPT-11 ; Camptothecin ; Radiation ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: Topoisomerase inhibitors including camptothecin are being studied as potential radiosensitizers. CPT-11 is a derivative of camptothecin and is clinically available. In this study, we investigated the effects of SN-38 (an active metabolite of CPT-11) on four nonirradiated and irradiated murine fibroblast cell lines with different p53 statuses to clarify the role of p53 in the radiosensitizing activity of SN-38. Materials and methods: Four fibroblast cell lines, MT158, MT158/neo, MT158/wtp53 and MT158/mp53 with the same genetic background but with different p53 statuses, were used. Exponentially growing cells were treated with SN-38 (200 nM) and incubated with the drug for 30 min. Cells were then irradiated (0 to 12 Gy) and further incubated with the drug for 2 h. The cell survival rate was determined using a conventional clonogenic assay. The effects of the treatments on the cell cycle were analyzed with a flow cytometric assay. Apoptosis after these treatments was also detected by an annexin V assay. Results: There were no significant differences in sensitivity to radiation or SN-38 treatment among these cell lines. The combined treatment of irradiation and SN-38 showed supraadditive effects in all four cell lines independent of their p53 status. Transient arrest in G2 with a decreased percentage of cells in both the S and G1 phases was observed 8 h after treatment with either SN-38 alone, radiation or their combination, regardless of the p53 status. No significant differences in frequency of apoptosis were observed between treatment and control groups in two cell lines with or without wild-type p53. Conclusion: The combination of irradiation and SN-38 treatment showed supraadditive effects in all four cell lines tested, and the p53 status did not play a role in the combination effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002800051003
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Bax and Bcl-2 expressions predict response to radiotherapy in human cervical cancer (1998)
    Springer
    Journal of cancer research and clinical oncology 124 (1998), S. 503-510 
    Details
    ISSN: 1432-1335
    Keywords: Key words Bax ; Bcl-2 ; Radiotherapy ; Cervical carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: AbstractPurpose: The ratio of Bcl-2 to Bax expression determines survival or death following an apoptotic stimulus. In order to establish a new predictor of the outcome of treatment for human cervical carcinoma, we investigated the relationship between the expressions of the Bax and Bcl-2 proteins and the response to radiotherapy after the administration of 10.8 Gy. Methods: A total of 44 patients with histologically proven carcinoma of the uterine cervix, including three with recurrent cervical stump carcinomas, were treated with definitive radiotherapy. The presence of mutations in exons 5–8 of the p53 gene was analyzed by a single-strand conformation polymorphism analysis and DNA sequencing. Results: Forty patients were found to have wild-type p53, and the remaining four had mutant p53. The Bax and Bcl-2 protein expressions prior to radiotherapy did not correlate with response and survival. However, the Bax and Bcl-2 protein expressions after radiotherapy correlated with both response and survival. Bax-positive tumors showed significantly better responses than the Bax-negative tumors after 10.8 Gy radiation (P = 0.0002). In contrast, the Bcl-2-positive tumors showed significantly poorer responses than the Bcl-2-negative tumors after radiation (P = 0.002). Increased Bax expression after the 10.8 Gy radiotherapy was found to be correlated with good survival (P = 0.04). In contrast, increased Bcl-2 expression after such radiotherapy was correlated with poor survival (P = 0.002). Conclusion: The levels of Bax and Bcl-2 expression after 10.8 Gy radiotherapy are useful prognostic markers in patients with human cervical carcinoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004320050206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    UV hypersensitivity of yeast linear plasmids (1994)
    Springer
    Current genetics 26 (1994), S. 369-373 
    Details
    ISSN: 1432-0983
    Keywords: Yeast linear plasmids ; UV curing ; Photoreactivation ; Repair
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Kluyveromyces linear plasmids pGKL 1 and pGKL2, encoding killer activity, were efficiently cured by UV irradiation. This event was investigated in more detail by the use of the terminal protein (TP)-associated cytoplasmic linear plasmids, pJKL1 and pRKL2, with a selectable marker LEU2. This observation was compared with the UV effect on the nuclear plasmids pLS1 (telomere-associated linear form) and YCp121 (centromere-integrated circular form), indicating that the UV hypersensitivity was specific to the cytoplasmic plasmids. Using rad4 and wildtype strains of S. cerevisiae, both pJKL1 and the nuclear plasmids were found to respond not only to photoreactivation repair but also to excision repair of UV-induced DNA damage. Thus these DNA repair systems were functional for both the nuclear and cytoplasmic plasmids in yeast, and it was suggested that the UV hypersensitivity of cytoplasmic plasmids might have been caused by a defect in other repair systems or in the TP-primed replication. Possibly TP-associated Debaryomyces linear plasmids were also UV hypersensitive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310503
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Characteristics of DNA repair of a UV-sensitive mutant (radC) of Dictyostelium discoideum (1985)
    Springer
    Molecular genetics and genomics 198 (1985), S. 385-389 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A radiation-sensitive mutant, TW8(radC), of Dictyostelium discoideum is more sensitive to ultraviolet light (UV) killing than the parental wild strain NC4(RAD +), but is resistant to 4-nitroquinoline 1-oxide (4NQO) at almost the same level as NC4. In TW8 amoebae, single-strand breaks of DNA molecules were hardly detectable immediately after UV irradiation, and the removal of pyrimidine dimers was depressed during the postirradiation incubation when compared with that of NC4 amoebae. After treatment with 4NQO, however, single-strand breaks were detected in TW8 amoebae. The almost complete rejoining of these breaks was also detected after the removal of 4HAQO-adducts. The TW8 amoebae have an efficient repair capacity against DNA damage caused by 4NQO, MMS, MMC and MNNG but not UV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00332927
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Induction of phr gene expression by irradiation of ultraviolet light in Escherichia coli (1987)
    Springer
    Molecular genetics and genomics 209 (1987), S. 200-202 
    Details
    ISSN: 1617-4623
    Keywords: phr ; SOS induction ; Ultraviolet light ; DNA damage ; DNA repair
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To measure the degree of phr gene induction by DNA-damaging agents, the promoter region was fused to the coding region of the lacZ gene in plasmid pMC1403. The new plasmids were introduced into Escherichia coli cells having different repair capabilities. More efficient induction of phr gene expression was detected in a uvrA − strain as compared with the wild-type strain. In addition, obvious induction was detected in uvrA − cells treated by 4-nitroquinoline 1-oxide and mitomycin C. Nalidixic acid, an inhibitor of DNA gyrase, also induced phr gene expression. In contrast, little induced gene expression was noted in UV-irradiated lexA − and recA − strains. It is suggested from these results that induction of the phr gene is one of the SOS responses. Possible nucleotide sequences which could be considered to constitute an SOS box were found at the regulator region of the phr gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00329860
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...