The possible involvement of metal ions and free radicals in the cytotoxic mechanism of Adriamycin (ADR) was investigated, using a model system of Escherichia coli cells. It is shown that E. coli mediated the production of free radicals under anaerobic (ADR-semiquinone) and aerobic (superoxide) conditions. ADR-induced loss of colony-forming ability was enhanced by the addition of iron (Fe) chelates. These observations suggested that a Fenton-type free radical mechanism was responsible for ADR toxicity. However, the mortality rate was essentially unchanged by the exclusion of oxygen. It was also unaffected by the addition of H2O2, catalase, or chelating agents. Cu(II), Zn(II) or Mg(II) had no effect on ADR toxicity. ADR and iron chelates did not induce measurable amounts of DNA strand-breaks. These observations suggest a mechanism of ADR-induced cell killing that is enhanced by Fe chelates, but does not directly involve oxygen-derived free radicals.
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Nat Commun
January 2025
Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
The mycobacterial ABC transporter IrtAB features an ABC exporter fold, yet it imports iron-charged siderophores called mycobactins. Here, we present extensive cryo-EM analyses and DEER measurements, revealing that IrtAB alternates between an inward-facing and an outward-occluded conformation, but does not sample an outward-facing conformation. When IrtAB is locked in its outward-occluded conformation in nanodiscs, mycobactin is bound in the middle of the lipid bilayer at a membrane-facing crevice opening at the heterodimeric interface.
View Article and Find Full Text PDFAlzheimers Dement
January 2025
Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, USA.
Introduction: Iron-mediated cell death (ferroptosis) is a proposed mechanism of Alzheimer's disease (AD) pathology. While iron is essential for basic biological functions, its reactivity generates oxidants which contribute to cell damage and death.
Methods: To further resolve mechanisms of iron-mediated toxicity in AD, we analyzed post mortem human brain and ApoEFAD mice.
Sci Rep
January 2025
Instituto Multidisciplinario de Investigación y Transferencia Agroalimentaria y Biotecnológica (IMITAB, UNVM-CONICET), Villa María, Argentina.
This study investigated plant growth-promoting (PGP) mechanisms in Priestia aryabhattai VMYP6 and Paenibacillus sp. VMY10, isolated from tomato roots. Their genomes were initially assessed in silico through various approaches, and these observations were then compared with results obtained in vitro and in vivo.
View Article and Find Full Text PDFNutrients
January 2025
Escuela de Kinesiología, Facultad de Salud, Universidad Santo Tomás, Talca 3460000, Chile.
Unlabelled: Dental caries remains a prevalent chronic disease driven by dysbiosis in the oral biofilm, with playing a central role in its pathogenesis.
Objective: This study aimed to assess the effect of D-tagatose on cariogenic risk by analyzing randomized clinical trials (RCTs).
Methods: A systematic literature review was conducted targeting RCTs published up to 2024 in eight databases and two gray literature sources.
Molecules
January 2025
Marine Biodiscovery Centre, Department of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Old Aberdeen AB24 3UE, UK.
The isolation and characterization of bioactive metabolites from species continue to represent a vital area of research, given their potential in natural product drug discovery. In this study, we characterize a new siderophore called legonoxamine I, together with a known compound, streptimidone, from the talented soil bacterium sp. MA37, using chromatographic techniques and spectroscopic analysis.
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