Nanodisc-associated acetylcholinesterase as a novel model system of physiological relevant membrane-bound cholinesterases. Inhibition by phenolic compounds.

Acetylcholinesterase (AChE) plays a pivotal role in the cholinergic system, and its inhibition is sought after in a wide range of applications, from insect control to Alzheimer's disease treatment. While the primary physiological isoforms of AChE are membrane-bound proteins, most assays for discovering new, safer, and potent inhibitors are conducted using commercially available soluble isoforms, such as the electric eel AChE (eeAChE). In this study, we conducted a comparative analysis of the activity and selectivity to phenolic inhibitors of recombinant human AChE, eeAChE and a mutant variant of human AChE known as dAChE4.

Improvement of Key Molecular Events Linked to Alzheimer's Disease Pathology Using Postbiotics.

In the past 50 years, life expectancy has increased by more than 20 years. One consequence of this increase in longevity is the rise of age-related diseases such as dementia. Alzheimer's disease (AD) is the most common form of dementia, accounting for 60-70% of cases.

Inactivation of Listeria monocytogenes and Salmonella Typhimurium in strawberry juice enriched with strawberry polyphenols.

Background: Low molecular-weight phenolic fractions (LMPFs) were extracted from Albion (LMPF-A) and Camarosa (LMPF-C) strawberry cultivars. Their antibacterial activity against Listeria monocytogenes and Salmonella Typhimurium cocktails in vitro and in vivo was investigated using strawberry juice as a food model. This study also sought to determine their antibacterial mechanism.

Bacteriocin enterocin CRL35 is a modular peptide that induces non-bilayer states in bacterial model membranes.

The mechanism of action of the anti-Listeria peptide enterocin CRL35 was studied with biophysical tools by using lipid mixtures that mimicked Gram-positive plasma membranes. Langmuir monolayers and infrared spectroscopy indicated that the peptide readily interacted with phospholipid assembled in monolayers and bilayers to produce a dual effect, depending on the acyl chains. Indeed, short chain mixtures were disordered by enterocin CRL35, but the gel-phases of membranes composed by longer acyl chains were clearly stabilized by the bacteriocin.

Stability of the Typhimurium mutant under different stress conditions.

The virulence genes of are modulated during infection by several regulatory systems, and the RcsCDB system is one of the most important of these. The . Typhimurium EG14873 () strain harbours the point mutation, displaying a constitutive activation of this system, which is characterized by mucoid colonies and attenuated virulence phenotypes.

Membrane order and ionic strength modulation of the inhibition of the membrane-bound acetylcholinesterase by epigallocatechin‑3‑gallate.

In the present work, we analyzed how external factors can modulate the efficiency of epigallocatechin‑3‑O‑gallate (EGCG) inhibition of a membrane-bound isoform of the acetylcholinesterase. Increasing the ionic strength but not the osmolarity of the bulk medium proved to be an important factor. In addition, we verified a clear correlation between the inhibitory activity with the order degree of the membranes by using cholesterol-partially depleted red blood cell ghosts.

Nisin Z produced by Lactococcus lactis from bullfrog hatchery is active against Citrobacter freundii, a red-leg syndrome related pathogen.

Lactococcus lactis subsp. lactis CRL 1584 isolated from a bullfrog hatchery produces a bacteriocin that inhibits both indigenous Citrobacter freundii (a Red-Leg Syndrome related pathogen) and Lactobacillus plantarum, and Listeria monocytogenes as well. Considering that probiotics requires high cell densities and/or bacteriocin concentrations, the effect of the temperature on L.

Differential inhibition of human erythrocyte acetylcholinesterase by polyphenols epigallocatechin-3-gallate and resveratrol. Relevance of the membrane-bound form.

The activity of acetylcholinesterase (AChE) from human erythrocytes was tested in the presence of the phenolic compounds resveratrol and epigallocatechin-3-gallate (EGCG). Even though the stilbene barely changed this enzymatic activity, EGCG did inhibit AChE. Importantly, it preferentially acted on the membrane-bound enzyme rather than on its soluble form.

The key role of membranes in amyloid formation from a biophysical perspective.

Even though our knowledge of how proteins misfold and aggregate is deeper nowadays, the mechanisms driving this process are still poorly understood. Among the factors involved, membranes should be taken into account. Indeed, convincing evidence suggests that membranes may influence protein folding, misfolding and aggregation.

Proton motive force dissipation precludes interaction of microcin J25 with RNA polymerase, but enhances reactive oxygen species overproduction.

Background: Microcin J25 targets the RNA polymerase as well as bacterial membranes. Because there is scarce information on the relationship between the uptake and the activity, a fluorescent microcin J25-derivative was used to further characterize its mechanism of action.

Methods: MccJ25 I13K was labeled with FITC and its uptake by sensitive cells was assessed by fluorescence measurements from supernatants of MccJ25-Escherichia coli suspensions.

Membrane viscosity is a major modulating factor of the enterocin CRL35 activity.

Enterocin CRL35 activity is deeply influenced by the membrane viscosity as could be demonstrated performing determinations of the minimal inhibitory concentrations (MIC) at different temperatures and analyzing the membrane viscosity in these cells as well as in resistant bacteria. In all the cases, bacteriocin activity was linked to higher levels of viscosity. This finding was confirmed studying the interaction of enterocin CRL35 with liposomes composed of dimyristoyl phosphatidylcholine: dimyristoyl phosphatidylglycerol (9:1) in both gel and liquid-crystalline phases.

Antimitochondrial activity displayed by the antimicrobial peptide microcin J25.

In this report we studied the effect of the antimicrobial peptide, microcin J25, on the rat heart mitochondria. This peptide induced an important inhibition of the ATP synthesis with the concomitant enhancement of the ATP degradation. These effects were the result of two processes: on one hand, microcin J25 was able to insert into the membrane and hence alter its permeability with the consequent dissipation of the proton motive force.

Enhancement of antibiotic activity by sub-lethal concentrations of enterocin CRL35.

Objective: The aim of this study was to evaluate the interaction of several conventional antibiotics with sub-lethal concentrations of enterocin CRL35, a cationic peptide, on Listeria innocua 7.

Methods: Susceptibility of L. innocua 7 cells to the combination of enterocin CRL35 and non-peptide antibiotics (cefalexin, ampicillin, ciprofloxacin, nalidixic acid, erythromycin, chloramphenicol, vancomycin and tetracycline) was assayed using the broth dilution method and killing curves.