Reversions induced by N-hydroxy-2-acetylaminofluorene (N-OH-AAF) were measured in the Salmonella/microsome quantitative plate assay using various concentrations of Salmonella typhimurium strain TA1538. The number of induced revertants increased with an increasing number of bacteria/plate, but the variation in reversion frequency was not as great as the variation in bacterial concentration. The effects of bacterial concentration on reversion fixation, phenotypic expression, selection of his+ revertants, and the interaction of the mutagen with bacterial DNA were examined. Suspension cultures of TA1538 were exposed to N-OH-AAF and various dilutions were prepared and assayed for revertants/10(8) bacteria. Reversion frequencies were very dependent on bacterial concentration between approximately 0.2 X 10(8) and 2 X 10(8) bacteria/plate. Revertants/10(8) TA1538 were reduced above about 2 X 10(8) bacteria/plate, indicating that culture conditions limited reversion fixation, expression and/or selection at these concentrations. The number of spontaneous revertants/plate determined both from bacteria exposed to dimethyl sulfoxide in suspension culture and in the Salmonella/microsome assay were not greatly affected by bacterial concentration. To study the effect of bacterial concentration on the interaction of the mutagen with bacterial DNA, various concentrations of TA1538 were exposed to the same dose of N-OH-AAF. Both revertants/10(8) TA1538 and DNA adducts varied inversely with bacterial concentration. The effect of bacterial concentration on both reversion fixation and/or expression and on mutagen binding to DNA may influence reversion frequencies in the Salmonella/microsome assay.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/em.2860050406 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Environmental exposure to single and combined ZnO and TiO nanoparticles: Implications for rainbow trout gill immune functions and microbiota.
Chemosphere
January 2025
Research Unit in Environmental and Evolutionary Biology (URBE), Institute of Life Earth and Environment, University of Namur, 61 Rue de Bruxelles, B-5000, Namur, Belgium.
ZnO and TiO nanoparticles (NPs) are widely employed for their antibacterial properties, but their potential environmental impact is raising concerns. This study aimed to assess their single and combined effects at environmentally relevant concentrations (210 μg L) on rainbow trout (Oncorhynchus mykiss) gills microbiota and immune functions. 16S rRNA gene sequencing performed after 5 and 28 days of exposure suggests that TiO NPs had a more immediate impact on bacterial diversity, while prolonged exposure to the mixture altered community composition.
View Article and Find Full Text PDF3D nanocomposites of β-TCP-HBO-Cu with improved mechanical and biological performances for bone regeneration applications.
Sci Rep
January 2025
Advanced Glass and Glass Ceramic Research Laboratory, Department of Physics, University of Lucknow, Lucknow, 226007, India.
Recently, 3-D porous architecture of the composites play a key role in cell proliferation, bone regeneration, and anticancer activities. The osteoinductive and osteoconductive properties of β-TCP allow for the complete repair of numerous bone defects. Herein, β-TCP was synthesized by wet chemical precipitation route, and their 3-D porous composites with HBO and Cu nanoparticles were prepared by the solid-state reaction method with improved mechanical and biological performances.
View Article and Find Full Text PDFElectrochemical aptasensor for the selective detection of vancomycin based on nanostructured "in-lab" printed electrodes.
Mikrochim Acta
January 2025
Department of Analytical Chemistry, Faculty of Pharmacy, "Iuliu Hațieganu" University of Medicine and Pharmacy, 4 Pasteur Street, 400349, Cluj-Napoca, Romania.
A label-free, flexible, and disposable aptasensor was designed for the rapid on-site detection of vancomycin (VAN) levels. The electrochemical sensor was based on lab-printed carbon electrodes (C-PE) enriched with cauliflower-shaped gold nanostructures (AuNSs), on which VAN-specific aptamers were immobilized as biorecognition elements and short-chain thiols as blocking agents. The AuNSs, characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), enhanced the electrochemical properties of the platform and the aptamer immobilization active sites.
View Article and Find Full Text PDFLactiplantibacillus plantarum 22 A-3 ameliorates leaky gut in mice through its anti-inflammatory effects.
Sci Rep
January 2025
Department of Gastroenterology and Hepatology, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
There are limited studies on the improvement of leaky gut with minor inflammation associated with various diseases. To explore the therapeutic potential of Lactiplantibacillus plantarum 22 A-3, a member of the Lactobacillus species, in addressing a leaky gut. Lactiplantibacillus plantarum 22 A-3 was administered to a leaky gut mice model with low dextran sulfate sodium concentrations.
View Article and Find Full Text PDFStructural, morphological and biological assessment of magnetic hydroxyapatite with superior hyperthermia potential for orthopedic applications.
Sci Rep
January 2025
Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
Hydroxyapatite (HA) is an important constituent of natural bone. The properties of HA can be enhanced with the help of various ionic substitutions in the crystal lattice of HA. Iron (Fe) is a vital element present in bones and teeth.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!