Production of clavulanic acid (CA) by Streptomyces clavuligerus in a shake-flask culture increased from 92 to 180 mg l(-1) with an increased O2 transfer efficiency (0.039 --> 0.058 s(-1)), which maintained the redox potential values above -250 mV. Compared with traditional measures, such as dissolved O2 concentration and respiratory activity, the redox potential can easily be determined and correlates closely with CA production. It can therefore be used to monitor microbial activities during biosyntheses of secondary metabolites.
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http://dx.doi.org/10.1007/s10529-005-3727-0 | DOI Listing |
Mikrochim Acta
January 2025
Department of Chemistry, Faculty of Basic Sciences, Ayatollah Boroujerdi University, Boroujerd, Iran.
A cost-effective strategy is reported utilizing ionic liquid (IL), 1-hexyl-3-methylimidazolium bisulfate ([HMIM] HSO), to delaminate TiC MXene, thereby enhancing its efficiency in electrocatalyzing tryptophan (Trp) oxidation. The positively charged IL effectively intercalates within the negatively charged MXene layers, fostering structural stability through π-π stacking and electrostatic interactions. Consequently, the resulting IL-TiC composite not only maintained the inherent electronic conductivity of TiC but also significantly augmented its electrocatalytic prowess.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Chemistry and Chemical Engineering, Nanchang University, Nanchang, Jiangxi 330031, P. R. China.
A Ni/photoredox dual-catalyzed multicomponent cross-electrophile coupling of N-vinyl amides with (hetero)aryl halides and (2°, 3°)-alkyl redox-active esters in the presence of cheap reductant Hantzsch ester is reported here. This reductive protocol provides direct access to various synthetically challenging chiral α-arylamides in good yields and excellent enantioselectivities (up to 99% ee, with the majority exceeding 97% ee), which can be further derived into chiral primary and secondary amines. Preliminary experimental studies shed light on the potential catalytic pathways.
View Article and Find Full Text PDFRedox Biol
January 2025
Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, The University of Iowa College of Medicine, Iowa City, IA 52242, USA; Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, 52242, USA.
Differences in cancer and normal cell oxidative metabolism provide a unique therapeutic opportunity for developing combined modality approaches with redox-active small molecules as radio-chemosensitizers that are well-tolerated by normal tissues. Pentaazamacrocyclic Mn (II)-containing (MnPAM) superoxide dismutase (SOD) mimetics and pharmacological ascorbate given IV to achieve [mM] plasma levels (pharmacological ascorbate: P-AscH‾) have been shown to act individually as cancer cell radio- and chemosensitizers via the generation of HOin vivo. The current study shows that the combination of newly developed MnPAM dismutase mimetic, rucosopasem manganese (RUC) with P-AscH‾ radio-sensitizes non-small cell lung cancer cells (NSCLC) and increases steady state levels of intracellular HO with no additional toxicity to normal human bronchial epithelial cells (HBECs).
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Physics, Chair for Functional Materials, TUM School of Natural Sciences, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany.
Solid additives have garnered significant attention due to their numerous advantages over liquid additives. This study explores the potential of the green-fluorescent conjugated polymer denoted Atums Green as a solid additive in green-solvent-based PBDB-TF-T1:BTP-4F-12 solar cells. Even tiny amounts of Atums Green doping significantly improve the device performance.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Chemistry Division, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
This review discusses the properties of strongly oxidizing radicals in organic and aqueous media and highlights the challenges in obtaining accurate values of their reduction potentials. Transient redox equilibrium methods based on the use of strong photooxidants or initiated by pulse radiolysis are shown to provide versatile approaches for decoupling electron transfer reactions from follow-up reactivity of unstable radical species, resulting in accurate values of reduction potentials of very positive couples, including some solvent radical cations. We also show that correlations of reduction potentials with Hammett ∑+p parameters, as well as gas phase ionization potentials, can be used to estimate the redox properties of unknown couples within a homologous series of compounds.
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