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Abstract: New acetylcholinesterase inhibitors in the tetracyclic triterpene series were synthesized, tested in vitro for the inhibition of cholinesterases (different sources of AChE and BuChE) and for the ability to prevent AChE-induced Aβ aggregation. Some compounds have hAChE IC50 values in the nanomolar range and showed ability to block the AChE-induced Aβ aggregation. The mode of interaction between EeAChE and compounds 1 and 36e was investigated using docking and molecular dynamics simulations. These studies suggested that both compounds interact simultaneously with the catalytic and the peripheral sites of AChE, and the nature of protein-ligand interactions is mainly hydrophobic. [Copyright &y& Elsevier]

Pseudomonas aeruginosa , a ubiquitous opportunistic pathogen considered one of the paradigms of antimicrobial resistance, is among the main causes of hospital-acquired and chronic infections associated with significant morbidity and mortality. This growing threat results from the extraordinary capacity of P. aeruginosa to develop antimicrobial resistance through chromosomal mutations, the increasing prevalence of transferable resistance determinants (such as the carbapenemases and the extended-spectrum β-lactamases), and the global expansion of epidemic lineages. The general objective of this initiative is to provide a comprehensive update of P. aeruginosa resistance mechanisms, especially for the extensively drug-resistant (XDR)/difficult-to-treat resistance (DTR) international high-risk epidemic lineages, and how the recently approved β-lactams and β-lactam/β-lactamase inhibitor combinations may affect resistance mechanisms and the definition of susceptibility profiles. To address this challenge, the European Study Group for Antimicrobial Resistance Surveillance (ESGARS) from the European Society of Clinical Microbiology and Infectious Diseases launched the 'Improving Surveillance of Antibiotic-Resistant Pseudomonas aeruginosa in Europe (ISARPAE)' initiative in 2022, supported by the Joint programming initiative on antimicrobial resistance network call and included a panel of over 40 researchers from 18 European Countries. Thus, a ESGARS-ISARPAE position paper was designed and the final version agreed after four rounds of revision and discussion by all panel members. To provide an update on (a) the emerging resistance mechanisms to classical and novel anti-pseudomonal agents, with a particular focus on β-lactams, (b) the susceptibility profiles associated with the most relevant β-lactam resistance mechanisms, (c) the impact of the novel agents and resistance mechanisms on the definitions of resistance profiles, and (d) the globally expanding XDR/DTR high-risk lineages and their association with transferable resistance mechanisms. The evidence presented herein can be used for coordinated epidemiological surveillance and decision making at the European and global level. [ABSTRACT FROM AUTHOR]

The cell envelope of Gram-negative bacteria is a multilayered structure essential for bacterial viability; the peptidoglycan cell wall provides shape and osmotic protection to the cell, and the outer membrane serves as a permeability barrier against noxious compounds in the external environment. Assembling the envelope properly and maintaining its integrity are matters of life and death for bacteria. Our understanding of the mechanisms of envelope assembly and maintenance has increased tremendously over the past two decades. Here, we review the major achievements made during this time, giving central stage to the amino acid cysteine, one of the least abundant amino acid residues in proteins, whose unique chemical and physical properties often critically support biological processes. First, we review how cysteines contribute to envelope homeostasis by forming stabilizing disulfides in crucial bacterial assembly factors (LptD, BamA, and FtsN) and stress sensors (RcsF and NlpE). Second, we highlight the emerging role of enzymes that use cysteine residues to catalyze reactions that are necessary for proper envelope assembly, and we also explain how these enzymes are protected from oxidative inactivation. Finally, we suggest future areas of investigation, including a discussion of how cysteine residues could contribute to envelope homeostasis by functioning as redox switches. By highlighting the redox pathways that are active in the envelope of Escherichia coli, we provide a timely overview of the assembly of a cellular compartment that is the hallmark of Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

The respiratory chain bc 1 complex is central to mitochondrial bioenergetics and the target of antiprotozoals. We characterized a modified yeast bc 1 complex that more closely resemble Plasmodium falciparum enzyme. The mutant version was generated by replacing ten cytochrome b Q o site residues by P. falciparum equivalents. The Plasmodium -like changes caused a major dysfunction of the catalytic mechanism of the bc 1 complex resulting in superoxide overproduction and respiratory growth defect. The defect was corrected by substitution of the conserved residue Y279 by a phenylalanine, or by mutations in or in the vicinity of the hinge domain of the iron–sulphur protein. It thus appears that side-reactions can be prevented by the substitution Y279F or the modification of the iron–sulphur protein hinge region. Interestingly, P. falciparum — and all the apicomplexan — contains an unusual hinge region. We replaced the yeast hinge region by the Plasmodium version and combined it with the Plasmodium -like version of the Q o site. This combination restored the respiratory growth competence. It could be suggested that, in the apicomplexan, the hinge region and the cytochrome b Q o site have co-evolved to maintain catalytic efficiency of the bc 1 complex Q o site. [ABSTRACT FROM AUTHOR]

Albendazole (ABZ) exhibits a potent antiparasitic activity against a broad spectrum of parasites. Unfortunately, the very low water solubility of ABZ (0.2 μg mL −1 , 0.7 μM) impairs considerably its formulation. Phase solubility diagrams showed that α-cyclodextrin (10% w/w), hydroxypropyl-β-cyclodextrin (40% w/w) and sulfobutylether-β-cyclodextrin (40% w/w) allowed an increase of apparent solubility with enhancement factors of 570, 3970, and 5880, respectively. The apparent aqueous solubility of ABZ was markedly increased from 0.2 μg mL −1 (0.7 μM) without cyclodextrins to 1.52 mg mL −1 (5.69 mM) with random methyl-β-cyclodextrin (Me-β-CD) (40% w/w). This corresponds to an apparent solubility enhancement factor of 7600 which is the maximal enhancement factor of ABZ apparent aqueous solubility ever reported in the literature using conventional cyclodextrins. The complexation mechanism between ABZ and cyclodextrins has been investigated using phase solubility diagrams, nuclear magnetic resonance ( 1 H NMR) coupled with two-dimensional nuclear Overhauser effect (NOESY) experiments and molecular docking calculations. The results showed that the central bicyclic fragment from ABZ interacts with Me-β-CD according to 1:1 stoichiometry. [ABSTRACT FROM AUTHOR]

Abstract: The parameterization of carbonic anhydrase binding site in OPLS-AA force field was performed using quantum chemistry calculations. Both OH2 and OH− forms of the binding site were considered, showing important differences in terms of atomic partial charges. Three different parameterization protocols were used, and the results obtained highlighted the importance of including an extended binding site in the charge calculation. The force field parameters were subsequently validated using standard molecular dynamics simulations. The results presented in this work should greatly facilitate the use of molecular dynamics simulations for studying the carbonic anhydrase, and more generally, the metallo-enzymes. [Copyright &y& Elsevier]

Highlights: [•] Trichoderma atroviridae UB-LMA is an endophytic fungus isolated from Taxus trees. [•] Compounds 2–4 belong to the harziane tetracyclic diterpene family. [•] Bicylic compound 1 is the biosynthetic precursor of harzianes. [•] Compound 3 exhibits cytotoxic activity against cancer cell lines. [Copyright &y& Elsevier]

Abstract: New docetaxel (Dtx) and cyclodextrin (CD) inclusion complexes having improved apparent water solubility (up to 9.98mgmL−1) were obtained from phase solubility diagrams. γ-CD and SBE-β-CD offered only poor solubility enhancements while considerable increases in apparent solubility were obtained with Me-β-CD (20%, w/w) and HP-β-CD (40%, w/w) (9.98mgmL−1 and 7.43mgmL−1, respectively). The complexation mechanism between Dtx and Me-β-CD was investigated by circular dichroism spectrometry, two-dimensional 1H NMR (NOESY) in D2O, isothermal titration calorimetry (ITC) and molecular docking calculations. Circular dichroism and NOESY confirmed the existence of non-covalent interactions between Dtx and Me-β-CD and suggested that the tert-butyl group (C6–C9) and two aromatic groups (C24–C29 and C30–C35) of Dtx interacted with the Me-β-CD molecules. The combination of ITC results to molecular docking calculations led to the identification of an unconventional sequential binding mechanism between Me-β-CD and Dtx. In this sequential binding, a Me-β-CD molecule first interacted with both tert-butyl and C30–C35 aromatic groups (K 1: 744M−1). Then a second Me-β-CD molecule interacted with the C24–C29 aromatic group (K 2: 202M−1). The entropy of the first interaction was positive, whereas a negative value of entropy was found for the second interaction. The opposite behavior observed for these two sites was explained by differences in the hydrophobic contact surface and functional group flexibility. [Copyright &y& Elsevier]

The occurrence of resistances in Gram negative bacteria is steadily increasing to reach extremely worrying levels and one of the main causes of resistance is the massive spread of very efficient β-lactamases which render most β-lactam antibiotics useless. Herein, we report the development of a series of imino-analogues of β-lactams (namely azetidinimines) as efficient non-covalent inhibitors of β-lactamases. Despite the structural and mechanistic differences between serine-β-lactamases KPC-2 and OXA-48 and metallo-β-lactamase NDM-1, all three enzymes can be inhibited at a submicromolar level by compound 7dfm , which can also repotentiate imipenem against a resistant strain of Escherichia coli expressing NDM-1. We show that 7dfm can efficiently inhibit not only the three main clinically-relevant carbapenemases of Ambler classes A (KPC-2), B (NDM-1) and D (OXA-48) with Ki' s below 0.3 μM, but also the cephalosporinase CMY-2 (class C, 86% inhibition at 10 μM). Our results pave the way for the development of a new structurally original family of non-covalent broad-spectrum inhibitors of β-lactamases. [Display omitted] • Forty azetidinimines synthesized and evaluated for their activity against carbapenemases. • Several compounds are submicromolar inhibitors of both MBLs (NDM-1) and SBLs of class A (KPC-2) and D (OXA-48). • One compound is also active against 4 other MBLs (NDM-4, NDM-7, NDM-9 and VIM-1), CTX-M-15 (class A) and CMY-2 (class C). • The same compound can repotentiate imipenem against a NDM-1-producing clinical isolate of E. coli. [ABSTRACT FROM AUTHOR]

The biological evaluation of a natural sesquiterpene dimer meiogynin A 1 , is described as well as that of five non-natural analogues. Although active on a micromolar range on the inhibition of Bcl-xL/Bak and Mcl-1/Bid interaction, meiogynin A 1 is not cytotoxic on three cell lines that overexpress Bcl-xL and Mcl-1. Contrarily, one of its analogues 6 with an inverted configuration on the side chain and an aromatic moiety replacing the cyclohexane ring was active on both target proteins, cytotoxic on a micromolar range and was found to induce apoptosis through a classical pathway. [ABSTRACT FROM AUTHOR]

We investigated the presence of carbapenemases in carbapenem-resistant Pseudomonas aeruginosa isolates, which were collected over a 14-month period in a Turkish hospital, with in-depth molecular characterization of carbapenemase-producing isolates. Among 45 study isolates, 2 isolates were identified as carbapenemase producers by both Carba NP and Carbapenem Inactivation Method tests, and only 1 of them gave a positive result in polymerase chain reaction tests for a carbapenemase gene (bla VIM). Whole genome sequencing of the 2 isolates revealed the presence of bla VIM-5 gene in an ST308 isolate, while the other one expressed IMP-7 in an ST357 isolate; both STs are considered high-risk clones. The 2 carbapenemase-producing isolates were multidrug resistant, as they harbored other resistance determinants, including a variant of the recently described plasmid-encoded fluoroquinolone resistance determinant crpP gene, crpP-2. We report for the first time P. aeruginosa high-risk clones carrying VIM-5– and IMP-7–type carbapenemases with multiple resistance determinants in Turkey. • Twenty percent carbapenem-resistant Pseudomonas aeruginosa isolates over a 14-month period in a Turkish hospital. • Among carbapenem-resistant P. aeruginosa isolates, 5% were carbapenemase producers. • Carbapenemase-producing P. aeruginosa high-risk clones from Turkey. • VIM-5–producing ST308 and IMP-7–producing ST357. • Novel plasmid-encoded fluoroquinolone resistance determinant crpP gene, crpP-2. [ABSTRACT FROM AUTHOR]

With the aim to develop new chemical tools based on simplified natural metabolites to help deciphering the molecular mechanism of necroptosis, simplified benzazole fragments including 2-aminobenzimidazole and the 2-aminobenzothiazole analogs were prepared during the synthesis of the marine benzosceptrin B. Conpounds inhibiting the RIPK1 protein kinase were discovered. A library of 54 synthetic analogs were prepared and evaluated through a phenotypic screen using the inhibition of the necrotic cell death induced by TNF-α in human Jurkat T cells deficient for the FADD protein. This article reports the design, synthesis and biological evaluation of a series of 2-aminobenzazoles on the necroptotic cell death through the inhibition of RIPK1 protein kinase. The 2-aminobenzimidazole and 2-aminobenzothiazole platforms presented herein can serve as novel chemical tools to study the molecular regulation of necroptosis and further develop lead drug candidates for chronic pathologies involving necroptosis. Image 1 • Design, synthesis of Benzosceptrin B-derived compounds as new necroptosis inhibitors. • SAR study on the 54 benzazoles on the TNF-α induced necroptosis in human Jurkat FADD-deficient cells. • Compounds AV123 (12) and MBM105 (67) inhibited RIPK1 with IC 50 values of 12.12 and 2.89 μM, respectively. • Potent, non-toxic and selective MBM105 (67) blocked the necroptotic but not the apoptotic cell death. [ABSTRACT FROM AUTHOR]

• Second description worldwide of LMB-1, a novel subclass B3 MBL in Citrobacter freundii 164 from Argentina. • LMB-1 confers reduced susceptibility to carbapenems and gives inconsistent results with carbapenemase confirmatory tests. • The bla LMB-1 gene was located on a 176-kb IncA/C2 plasmid. • The genetic environment of bla LMB-1 indicates an IS CR -like mobilization from the chromosome of Rheinheimera pacifica. • C. freundii 164 expressed CMY-150, a novel CMY-2 variant that increases ceftazidime and aztreonam MICs when expressed in E. coli. Carbapenemase-producing Enterobacterales expressing OXA-48, KPC, NDM, VIM or IMP enzymes are increasingly reported worldwide. We have characterized LMB-1, a novel metallo-β-lactamase (MBL) of Ambler class B3 from Citrobacter freundii 164 (Cf 164) clinical isolate from Buenos Aires, Argentina. Cf 164 displayed reduced susceptibility to carbapenems but gave inconsistent results with carbapenemase confirmatory tests, indicating the presence of a weak carbapenemase. Analysis of whole-genome sequencing (WGS) of Cf 164 using Resfinder revealed four β-lactamase genes coding for CTX-M-8, PER-2, TEM-1 and CMY-150, a novel chromosomally-encoded CMY variant. Kinetic parameters of purified CMY-150 did not reveal any carbapenemase activity. However, CMY-150 conferred higher minimum inhibitory concentrations (MICs) to E. coli for ceftazidime and aztreonam compared with CMY-2. The in-house-developed β-lactamase search software (ResMiner) in WGS data revealed a novel subclass B3 MBL named LMB-1. LMB-1 conferred resistance to penicillins and expanded-spectrum cephalosporins and reduced susceptibility to carbapenems in E. coli. The bla LMB-1 gene was located on a 176-kb IncA/C2 plasmid. LMB-1 shared 99% amino acid sequence identity with the MBL encoded in the chromosome of Rheinheimera pacifica, it's likely progenitor. Despite repeated attempts, LMB-1 could not be purified, thus only specific activities could indicate hydrolysis of carbapenems. Here we report on CMY-150, a novel CMY-2 variant that confers increased ceftazidime and aztreonam MICs to E. coli and the first description of LMB-1 in Argentina. This work underlines the need for several carbapenemase-producing Enterobacteriaceae (CPE) confirmatory tests, as this novel enzyme might have been missed using only one. Image, graphical abstract [ABSTRACT FROM AUTHOR]