X-Ray-Induced Heritable Damage (Small-Colony Formation) in Cultured Mammalian Cells

1964 ◽  
Vol 21 (4) ◽  
pp. 584 ◽  
Author(s):  
Warren K. Sinclair
Keyword(s):  
Colony Formation ◽  
Mammalian Cells ◽  
X Ray ◽  
Small Colony

Immediate X-Ray-Inducible Responses from Mammalian Cells

1994 ◽  
Vol 138 (1) ◽  
pp. S44 ◽  
Author(s):  
David A. Boothman ◽  
Gopa Majmudar ◽  
Tim Johnson
Keyword(s):  
Mammalian Cells ◽  
X Ray

scholarly journals Synthesis and X-ray crystal structure of [Ag(phendio)2]ClO4 (phendio = 1,10-phenanthroline-5,6-dione) and its effects on fungal and mammalian cells

BioMetals ◽  
2004 ◽  
Vol 17 (6) ◽  
pp. 635-645 ◽  
Author(s):  
Malachy McCann ◽  
Barry Coyle ◽  
Sinead McKay ◽  
Paul McCormack ◽  
Kevin Kavanagh ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mammalian Cells ◽  
X Ray

scholarly journals Induction, by thymidylate stress, of genetic recombination as evidenced by deletion of a transferred genetic marker in mouse FM3A cells.

1986 ◽  
Vol 6 (10) ◽  
pp. 3463-3469 ◽  
Author(s):  
D Ayusawa ◽  
H Koyama ◽  
K Shimizu ◽  
S Kaneda ◽  
K Takeishi ◽  
...  
Keyword(s):  
Genetic Marker ◽  
Thymidylate Synthase ◽  
Mammalian Cells ◽  
Genetic Recombination ◽  
Low Frequency ◽  
Coding Region ◽  
Physiological Factor ◽  
X Ray ◽  
Alu Sequence ◽  
Specific Manner

Studies were made on the genetic consequences of methotrexate-directed thymidylate stress, focusing attention on a human thymidylate synthase gene that was introduced as a heterologous genetic marker into mouse thymidylate synthase-negative mutant cells. Thymidylate stress induced thymidylate synthase-negative segregants with concomitant loss of human thymidylate synthase activity with frequencies 1 to 2 orders of magnitude higher than the uninduced spontaneous level in some but not all transformant lines. Induction of the segregants was suppressed almost completely by cycloheximide and partially by caffeine. Thymidylate stress did not, however, induce mutations, as determined by measuring resistance to ouabain or 6-thioguanine. Thymidylate synthase-negative segregants were also induced by other means such as bromodeoxyuridine treatment and X-ray irradiation. In each of the synthase-negative segregants induced by thymidylate stress, a DNA segment including almost the whole coding region of the transferred human thymidylate synthase gene was deleted in a very specific manner, as shown by Southern blot analysis with a human Alu sequence and a human thymidylate synthase cDNA as probes. In the segregants that emerged spontaneously at low frequency, the entire transferred genetic marker was lost. In the segregants induced by X-ray irradiation, structural alterations of the genetic marker were random. These results show that thymidylate stress is a physiological factor that provokes the instability of this exogenously incorporated DNA in some specific manner and produces nonrandom genetic recombination in mammalian cells.

scholarly journals Controlled Release of Ropivacaine from Single-Armed (1-PCL) and Four-Armed PCL (4-PCL) Microspheres

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Wei Xiong ◽  
Yue-kun Shen ◽  
Peng Dong ◽  
Ying Xiao ◽  
Xiong-qing Huang ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Cell Proliferation ◽  
Mammalian Cells ◽  
Great Promise ◽  
X Ray Diffraction ◽  
X Ray ◽  
Initial Release ◽  
Release Assay ◽  
Ft Ir

Sustained release of anesthesia has shown great promise in the treatment of chronic pain in patients. In this research, we used neutralized ropivacaine as an anesthesia and poly(ε-caprolactone) (PCL) with different architectures to systematically study how these architectures affect the release of ropivacaine. After optimizing the parameters of the preparation of microspheres, ropivacaine-loaded 1-PCL microspheres and 4-PCL microspheres were obtained. Fourier Transform infrared spectra (FT-IR) and X-ray diffraction spectra (XRD) confirmed that ropivacaine was encapsulated within the microsphere rather than inserted on the surface of the microsphere. Ropivacaine was found to be buried deeper in the 1-PCL microsphere than in the 4-PCL microsphere. In vitro release assay revealed that small crystalline grains interfered with ropivacaine release in 4-PCL microspheres during the initial release period, but then two kinds of microspheres showed a similar ropivacaine release rate. We basically proved that the architecture of PCL has a negligible effect on ropivacaine release. Cell proliferation test revealed that the release of products from the microspheres resulted in insignificant toxicity towards mammalian cells.

scholarly journals Inaktivierungsversuche mit homozygoten Hefestämmen verschiedenen Ploidiegrades

1964 ◽  
Vol 19 (10) ◽  
pp. 929-935 ◽  
Author(s):  
Sigrid Hempel ◽  
Wolfgang Laskowski
Keyword(s):  
Succinic Acid ◽  
Effective Dose ◽  
Colony Formation ◽  
Daughter Cell ◽  
Distinct Difference ◽  
X Rays ◽  
Uv Treatment ◽  
Fermentation Processes ◽  
X Ray ◽  
Effective Doses

A diploid Saccaromyces strain was treated with several doses of X-rays, UV and succinic acid peroxyde (BPO). The inactivation of the ability to form macroscopic colonies as well as the ability to form microcolonies of at least two cells to a few hundred cells has been compared with the inactivation of respiration and fermentation intensity. If the inactivation of macroscopic colony formation is taken as a measure of the effective dose applied, the formation of at least one daughter cell as well as respiration and fermentation intensity is reduced to approximately the same extent after BPO and X-ray treatment. In the latter case, however, much higher effective doses have to be applied and a distinct difference between respiration and fermentation sensitivity is observed. After UV-treatment the formation of at least one daughter cell is exceedingly more sensitive than the fermentation processes. The respiration processes behave most UV resistant. Possible reasons for the observed different relative sensitivities are discussed.

scholarly journals Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

2019 ◽  
Vol 15 ◽  
pp. 2631-2643 ◽  
Author(s):  
Heather J Lacey ◽  
Cameron L M Gilchrist ◽  
Andrew Crombie ◽  
John A Kalaitzis ◽  
Daniel Vuong ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Biosynthetic Pathway ◽  
Spectroscopic Analysis ◽  
Bioinformatics Analysis ◽  
Biosynthetic Gene Cluster ◽  
In Vitro Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Drimane Sesquiterpenoids

Chemical investigation of an undescribed Australian fungus, Aspergillus nanangensis, led to the identification of the nanangenines – a family of seven new and three previously reported drimane sesquiterpenoids. The structures of the nanangenines were elucidated by detailed spectroscopic analysis supported by single crystal X-ray diffraction studies. The compounds were assayed for in vitro activity against bacteria, fungi, mammalian cells and plants. Bioinformatics analysis, including comparative analysis with other acyl drimenol-producing Aspergilli, led to the identification of a putative nanangenine biosynthetic gene cluster that corresponds to the proposed biosynthetic pathway for nanangenines.

Radiation damage in soft X-ray microscopy of live mammalian cells

1991 ◽  
Vol 161 (3) ◽  
pp. 463-472 ◽  
Author(s):  
Kunio Shinohara ◽  
Atsushi Ito
Keyword(s):  
Radiation Damage ◽  
Mammalian Cells ◽  
X Ray

scholarly journals Genetic and Phenotypic Identification of Fusidic Acid-Resistant Mutants with the Small-Colony-Variant Phenotype in Staphylococcus aureus

2007 ◽  
Vol 51 (12) ◽  
pp. 4438-4446 ◽  
Author(s):  
Tobias Norström ◽  
Jonas Lannergård ◽  
Diarmaid Hughes
Keyword(s):  
Staphylococcus Aureus ◽  
Fusidic Acid ◽  
Mammalian Cells ◽  
Antimicrobial Agents ◽  
Structural Domain ◽  
Small Colony ◽  
Resistant Mutants ◽  
Substitution Mutations ◽  
Domain V ◽  
Domain I

ABSTRACT Small-colony variants (SCVs) of Staphylococcus aureus are a slow-growing subpopulation whose phenotypes can include resistance to aminoglycosides, defects in electron transport, and enhanced persistence in mammalian cells. Here we show that a subset of mutants selected as SCVs by reduced susceptibility to aminoglycosides are resistant to the antibiotic fusidic acid (FA) and conversely that a subset of mutants selected for resistance to FA are SCVs. Mutation analysis reveals different genetic classes of FA-resistant SCVs. One class, FusA-SCVs, have amino acid substitution mutations in the ribosomal translocase EF-G different from those found in classic FusA mutants. Most of these mutations are located in structural domain V of EF-G, but some are in domain I or III. FusA-SCVs are auxotrophic for hemin. A second class of FA-resistant SCVs carry mutations in rplF, coding for ribosomal protein L6, and are designated as FusE mutants. FusE mutants fall into two phenotypic groups: one auxotrophic for hemin and the other auxotrophic for menadione. Accordingly, we have identified new genetic and phenotypic classes of FA-resistant mutants and clarified the genetic basis of a subset of S. aureus SCV mutants. A clinical implication of these data is that FA resistance could be selected by antimicrobial agents other than FA.

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