Indirect Mechanisms Contribute to Biological Effects Produced by Decay of DNA-Incorporated Iodine-125 in Mammalian Cells In Vitro: Double-Strand Breaks

1998 ◽  
Vol 149 (2) ◽  
pp. 134 ◽  
Author(s):  
Malgorzata A. Walicka ◽  
S. James Adelstein ◽  
Amin I. Kassis
Keyword(s):  
Mammalian Cells ◽  
Biological Effects ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Iodine 125

Effect of double-strand breaks on homologous recombination in mammalian cells and extracts

1985 ◽  
Vol 5 (12) ◽  
pp. 3331-3336
Author(s):  
K Y Song ◽  
L Chekuri ◽  
S Rauth ◽  
S Ehrlich ◽  
R Kucherlapati
Keyword(s):  
Homologous Recombination ◽  
Mammalian Cells ◽  
Recombination Frequency ◽  
Double Strand Breaks ◽  
Base Pairs ◽  
In Vitro System ◽  
Strand Breaks ◽  
Cell Extracts ◽  
Nuclear Extracts

We examined the effect of double-strand breaks on homologous recombination between two plasmids in human cells and in nuclear extracts prepared from human and rodent cells. Two pSV2neo plasmids containing nonreverting, nonoverlapping deletions were cotransfected into cells or incubated with cell extracts. Generation of intact neo genes was monitored by the ability of the DNA to confer G418r to cells or Neor to bacteria. We show that double-strand breaks at the sites of the deletions enhanced recombination frequency, whereas breaks outside the neo gene had no effect. Examination of the plasmids obtained from experiments involving the cell extracts revealed that gene conversion events play an important role in the generation of plasmids containing intact neo genes. Studies with plasmids carrying multiple polymorphic genetic markers revealed that markers located within 1,000 base pairs could be readily coconverted. The frequency of coconversion decreased with increasing distance between the markers. The plasmids we constructed along with the in vitro system should permit a detailed analysis of homologous recombinational events mediated by mammalian enzymes.

scholarly journals XRCC4/XLF Interaction Is Variably Required for DNA Repair and Is Not Required for Ligase IV Stimulation

2015 ◽  
Vol 35 (17) ◽  
pp. 3017-3028 ◽  
Author(s):  
Sunetra Roy ◽  
Abinadabe J. de Melo ◽  
Yao Xu ◽  
Satish K. Tadi ◽  
Aurélie Négrel ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
Dna Ligase ◽  
End Joining ◽  
Strand Breaks ◽  
Ligase Iv ◽  
Cell Strains ◽  
Dna Ends

The classic nonhomologous end-joining (c-NHEJ) pathway is largely responsible for repairing double-strand breaks (DSBs) in mammalian cells. XLF stimulates the XRCC4/DNA ligase IV complex by an unknown mechanism. XLF interacts with XRCC4 to form filaments of alternating XRCC4 and XLF dimers that bridge DNA endsin vitro, providing a mechanism by which XLF might stimulate ligation. Here, we characterize two XLF mutants that do not interact with XRCC4 and cannot form filaments or bridge DNAin vitro. One mutant is fully sufficient in stimulating ligation by XRCC4/Lig4in vitro; the other is not. This separation-of-function mutant (which must function as an XLF homodimer) fully complements the c-NHEJ deficits of some XLF-deficient cell strains but not others, suggesting a variable requirement for XRCC4/XLF interaction in living cells. To determine whether the lack of XRCC4/XLF interaction (and potential bridging) can be compensated for by other factors, candidate repair factors were disrupted in XLF- or XRCC4-deficient cells. The loss of either ATM or the newly described XRCC4/XLF-like factor, PAXX, accentuates the requirement for XLF. However, in the case of ATM/XLF loss (but not PAXX/XLF loss), this reflects a greater requirement for XRCC4/XLF interaction.

scholarly journals Effect of double-strand breaks on homologous recombination in mammalian cells and extracts.

1985 ◽  
Vol 5 (12) ◽  
pp. 3331-3336 ◽  
Author(s):  
K Y Song ◽  
L Chekuri ◽  
S Rauth ◽  
S Ehrlich ◽  
R Kucherlapati
Keyword(s):  
Homologous Recombination ◽  
Mammalian Cells ◽  
Recombination Frequency ◽  
Double Strand Breaks ◽  
Base Pairs ◽  
In Vitro System ◽  
Strand Breaks ◽  
Cell Extracts ◽  
Nuclear Extracts

We examined the effect of double-strand breaks on homologous recombination between two plasmids in human cells and in nuclear extracts prepared from human and rodent cells. Two pSV2neo plasmids containing nonreverting, nonoverlapping deletions were cotransfected into cells or incubated with cell extracts. Generation of intact neo genes was monitored by the ability of the DNA to confer G418r to cells or Neor to bacteria. We show that double-strand breaks at the sites of the deletions enhanced recombination frequency, whereas breaks outside the neo gene had no effect. Examination of the plasmids obtained from experiments involving the cell extracts revealed that gene conversion events play an important role in the generation of plasmids containing intact neo genes. Studies with plasmids carrying multiple polymorphic genetic markers revealed that markers located within 1,000 base pairs could be readily coconverted. The frequency of coconversion decreased with increasing distance between the markers. The plasmids we constructed along with the in vitro system should permit a detailed analysis of homologous recombinational events mediated by mammalian enzymes.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

Bestimmung der DNA-Schädigung in vitro

2010 ◽  
Vol 49 (S 01) ◽  
pp. S64-S68
Author(s):  
E. Dikomey
Keyword(s):  
Dna Damage ◽  
Cell Lines ◽  
Chromosome Aberrations ◽  
Genetic Factors ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Cell Inactivation ◽  
Repair Mechanisms ◽  
Break Repair

SummaryIonising irradiation acts primarily via induction of DNA damage, among which doublestrand breaks are the most important lesions. These lesions may lead to lethal chromosome aberrations, which are the main reason for cell inactivation. Double-strand breaks can be repaired by several different mechanisms. The regulation of these mechanisms appears be fairly different for normal and tumour cells. Among different cell lines capacity of doublestrand break repair varies by only few percents and is known to be determined mostly by genetic factors. Knowledge about doublestrand break repair mechanisms and their regulation is important for the optimal application of ionising irradiation in medicine.

scholarly journals Boon and Bane of DNA Double-Strand Breaks

2021 ◽  
Vol 22 (10) ◽  
pp. 5171
Author(s):  
Ingo Schubert
Keyword(s):  
Negative Impact ◽  
Biological Effects ◽  
Double Strand Breaks ◽  
Immunoglobulin Gene ◽  
Dna Double Strand Breaks ◽  
Endogenous Factors ◽  
Strand Breaks ◽  
Chromatin Elimination ◽  
Evolutionary Consequences ◽  
Cell Lethality

DNA double-strand breaks (DSBs), interrupting the genetic information, are elicited by various environmental and endogenous factors. They bear the risk of cell lethality and, if mis-repaired, of deleterious mutation. This negative impact is contrasted by several evolutionary achievements for DSB processing that help maintaining stable inheritance (correct repair, meiotic cross-over) and even drive adaptation (immunoglobulin gene recombination), differentiation (chromatin elimination) and speciation by creating new genetic diversity via DSB mis-repair. Targeted DSBs play a role in genome editing for research, breeding and therapy purposes. Here, I survey possible causes, biological effects and evolutionary consequences of DSBs, mainly for students and outsiders.

scholarly journals Distinct Chemistries Define the Diverse Biological Effects of Plasma Activated Water Generated with Spark and Glow Plasma Discharges

2021 ◽  
Vol 11 (3) ◽  
pp. 1178
Author(s):  
Evanthia Tsoukou ◽  
Maxime Delit ◽  
Louise Treint ◽  
Paula Bourke ◽  
Daniela Boehm
Keyword(s):  
Mammalian Cells ◽  
Biomedical Application ◽  
Biological Effects ◽  
Mode Of Delivery ◽  
Chemical Species ◽  
Resistant Bacteria ◽  
Cytotoxic Activities ◽  
Promising Alternative ◽  
Plasma Activated Water

The spread of multidrug-resistant bacteria poses a significant threat to human health. Plasma activated liquids (PAL) could be a promising alternative for microbial decontamination, where different PAL can possess diverse antimicrobial efficacies and cytotoxic profiles, depending on the range and concentration of their reactive chemical species. In this research, the biological activity of plasma activated water (PAW) on different biological targets including both microbiological and mammalian cells was investigated in vitro. The aim was to further an understanding of the specific role of distinct plasma reactive species, which is required to tailor plasma activated liquids for use in applications where high antimicrobial activity is required without adversely affecting the biology of eukaryotic cells. PAW was generated by glow and spark discharges, which provide selective generation of hydrogen peroxide, nitrite and nitrate in the liquid. The PAW made by either spark or glow discharges showed similar antimicrobial efficacy and stability of activity, despite the very different reactive oxygen species (ROS) and reactive nitrogen species profiles (RNS). However, different trends were observed for cytotoxic activities and effects on enzyme function, which were translated through the selective chemical species generation. These findings indicate very distinct mechanisms of action which may be exploited when tailoring plasma activated liquids to various applications. A remarkable stability to heat and pressure was noted for PAW generated with this set up, which broadens the application potential. These features also suggest that post plasma modifications and post generation stability can be harnessed as a further means of modulating the chemistry, activity and mode of delivery of plasma functionalised liquids. Overall, these results further understanding on how PAL generation may be tuned to provide candidate disinfectant agents for biomedical application or for bio-decontamination in diverse areas.

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