University of Warsaw

This study examines the integration of climate risk into credit risk assessment within the banking sector. We review the types of climate-related risks and the channels through which they may affectfinancial institutions, including physical risks from extreme weather events, transitional risks, and regulatory pressures. The paper highlights key challenges in incorporating climate considerations into credit risk models, notably data limitations at both national and firm levels, as well as the limited historical data on climate-related financial impacts. The aim of this study is to examine the impact of climate risk on the credit risk of commercial banks. The empirical analysis is based on a sample of 438 commercial banks from 54 countries worldwide, spanning the period from 2016 to 2022. Our findings reveal complex and sometimes counterintuitive relationships, underscoring that integrating climate risk into credit assessments is a methodologically demanding process that requires careful interpretation of both data and indicators.

The development of effective delivery systems for peptide nucleic acids (PNAs) into bacterial cells remains a critical challenge inantisense therapeutics. We report thedesign and evaluation of hydroxamate siderophore-PNA conjugates that exploit bacterial iron uptake pathways for targeted delivery. We demonstrate that modulating thebackbone flexibility ofhydroxamate siderophores, through glycine or alanine spacers, enhances iron(III) binding affinity and PNA delivery efficiency intoEscherichiacoli cells. Molecular dynamics simulations revealed that glycine insertion increases backbone flexibility, enabling optimal coordination ofall three hydroxamate groups toiron(III). Circular dichroism spectroscopy and iron(III) competition assays confirmed that thesiderophores form stable Λ-configured ferric complexes, with theflexible siderophore showing superior iron(III)-binding affinity compared with theless flexible analog. Growth recovery experiments using E.coli mutants deficient inseveral transporters indicated recognition and internalization of thesiderophores via theTonB-dependent hydroxamate pathway. Molecular docking demonstrated theaffinity of these siderophores forE.coli hydroxamate receptors, with binding scores comparable to those ofnatural siderophores. All three siderophore carriers successfully delivered functional PNA targeting themrfp reporter geneintobacterial cells, achieving sequence-specific gene silencing as confirmed byfluorescence measurements and confocal microscopy. Additionally, bacteriostatic activity was observed for thebest-performing siderophore mimic conjugated withaPNA targeting theessential acpP gene.

Indole-tetrahydroazepine derivatives of iboga alkaloids (ibogalogs) exhibit antidepressant, anxiolytic, promnesic, and antineuropathic effects, mainly via serotonergic targets. However, their physicochemical properties relevant to redox biology, including antioxidant activity and membrane stability, have remained poorly characterized. We investigated the antioxidant properties of three ibogalogs: ibogaminalog (DM506), ibogainalog (IBG), and tabernanthalog (TBG), using model lipid membranes (liposomes), human erythrocytes, and rat hippocampal and cortical synaptosomes exposed to AAPH-induced oxidative stress. Physicochemical descriptors, bond dissociation enthalpies, and ionization potentials were also calculated to assess membrane interactions and the antioxidant potential. All ibogalogs protected erythrocytes by reducing hemolysis, potassium efflux, and malondialdehyde levels, with the strongest effects observed for TBG; none induced hemolysis or K+ efflux at 0.01-10 μM. Ibogalogs also decreased lipid peroxidation in rat hippocampal and cortical synaptosomes. In liposomal systems, TBG showed the highest efficacy against lipid-peroxyl-radical-induced peroxidation, whereas DM506 and IBG mainly slowed autoxidation. Theoretical analysis indicated that the methoxy group substitution critically influences bond dissociation enthalpies, radical delocalization, and antioxidant potency. This first physicochemical characterization of antioxidant properties of ibogalogs enhances the understanding of their membrane-protective actions, complementing their neuromodulatory profiles.