Antibacterial Activity and Action Mechanism of Synthetic Interleukin-8 Derived Peptides Against Flavobacterium psychrophilum.

In Chile, Atlantic salmon and rainbow trout face significant production challenges due to the presence of Flavobacterium psychrophilum, which generates severe disease issues and economic losses. To address this, the salmon industry relies on vaccines and antibiotics, the latter raising concerns about bacterial resistance. For that reason, our study explores an alternative strategy for controlling F.

A pH-Sensitive Fluorescent Chemosensor Turn-On Based in a Salen Iron (III) Complex: Synthesis, Photophysical Properties, and Live-Cell Imaging Application.

pH regulation is essential to allow normal cell function, and their imbalance is associated with different pathologic situations, including cancer. In this study, we present the synthesis of 2-(((2-aminoethyl)imino)methyl)phenol (HL1) and the iron (III) complex (Fe(L1)Br, ()), confirmed by X-ray diffraction analysis. The absorption and emission properties of complex were assessed in the presence and absence of different physiologically relevant analytes, finding a fluorescent turn-on when OH was added.

Synthesis of fluorescent chalcones, photophysical properties, quantitative structure-activity relationship and their biological application.

The development of fluorescent pigments is an area of interest in several research fields due to their high sensitivity. In the current study-eight known and three new N,N-dimethylamino-chalcones (12a-k) were synthesized with good yields using the Claisen-Schmidt reaction. For each molecular system, the photophysical properties, including the maximum absorption wavelength (λ), molar absorption coefficient (ε), maximum excitation wavelength (λ), maximum emission wavelength (λ), Stokes Shift (Δλ), fluorescence quantum yield (Φ), fluorescence lifetime (τ), radiative and non-radiative rate constants (k and k, respectively) were evaluated.

Arginine Homopeptide of 11 Residues as a Model of Cell-Penetrating Peptides in the Interaction with Bacterial Membranes.

Cell-penetrating peptides rich in arginine are good candidates to be considered as antibacterial compounds, since peptides have a lower chance of generating resistance than commonly used antibiotics. Model homopeptides are a useful tool in the study of activity and its correlation with a secondary structure, constituting an initial step in the construction of functional heteropeptides. In this report, the 11-residue arginine homopeptide (R11) was used to determine its antimicrobial activity against and and the effect on the secondary structure, caused by the substitution of the arginine residue by the amino acids Ala, Pro, Leu and Trp, using the scanning technique.

Effects of cholesterol on lipid vesicle fusion mediated by infectious salmon anaemia virus fusion peptides.

Studying the variables that affect the membrane fusion mechanism of enveloped viruses is important for developing new strategies to combat viral infections. We analysed the effects of lipid vesicle cholesterol content on membrane fusion that is facilitated by infectious salmon anaemia virus (ISAV) fusion peptides. Lipid mixing assays were performed to study membrane fusion in large unilamellar vesicles (LUV) composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), dipalmitoylphosphatidylcholine (DPPC) and cholesterol.

Sensitive fluorescent chemosensor for Hg(II) in aqueous solution using 4'-dimethylaminochalcone.

Mercury (Hg) is an element with high toxicity, especially to the nervous system, and fluorescent pigments are used to visualize dynamic processes in living cells. A little explored fluorescent core is chalcone. Herein, we synthesized chalcone (2E)-3-(4-(dimethylamino)phenyl)-1-phenylprop-2-en-1-one (8) and assessed its photophysical properties.

QSAR-driven synthesis of antiproliferative chalcones against SH-SY5Y cancer cells: Design, biological evaluation, and redesign.

Neuroblastoma is one of the most frequent types of cancer found in infants, and traditional chemotherapy has limited efficacy against this pathology. Thus, the development of new compounds with higher activity and selectivity than traditional drugs is a current challenge in medicinal chemistry research. In this study, we report the synthesis of 21 chalcones with antiproliferative activity and selectivity against the neuroblastoma cell line SH-SY5Y.

Coumarin-Resveratrol-Inspired Hybrids as Monoamine Oxidase B Inhibitors: 3-Phenylcoumarin -6-Styrylcoumarin.

Monoamine oxidases (MAOs) are attractive targets in drug design. The inhibition of one of the isoforms (A or B) is responsible for modulating the levels of different neurotransmitters in the central nervous system, as well as the production of reactive oxygen species. Molecules that act selectively on one of the MAO isoforms have been studied deeply, and coumarin has been described as a promising scaffold.

Inhibition of Caco-2 and MCF-7 cancer cells using chalcones: synthesis, biological evaluation and computational study.

Cancer is the second death cause worldwide, with breast and colon cancer among the most prevalent types. Traditional treatment strategies have several side effects that inspire the development of novel anticancer agents derived from natural sources, like chalcone derivatives. For this investigation, twenty-three chalcones () were synthesized and evaluated as antiproliferative agents against MCF-7 and Caco-2 cells, finding three and two compounds with similar or higher antiproliferative activity than daunorubicin, while only two chalcones showed better selectivity indexes than daunorubicin on MCF-7.

3-aryl-indolinones derivatives as antiplasmodial agents: synthesis, biological activity and computational analysis.

Malaria is an infectious illness, affecting vulnerable populations in Third World countries. Inspired by natural products, indole alkaloids have been used as a nucleus to design new antimalarial drugs. So, eighteen oxindole derivatives, analogues were obtained with moderate to excellent yields.

Combined 3D-QSAR and docking analysis for the design and synthesis of chalcones as potent and selective monoamine oxidase B inhibitors.

Monoamine oxidases (MAOs) are important targets in medicinal chemistry, as their inhibition may change the levels of different neurotransmitters in the brain, and also the production of oxidative stress species. New chemical entities able to interact selectively with one of the MAO isoforms are being extensively studied, and chalcones proved to be promising molecules. In the current work, we focused our attention on the understanding of theoretical models that may predict the MAO-B activity and selectivity of new chalcones.

Carfilzomib as a potential inhibitor of NADH-dependent enoyl-acyl carrier protein reductases of and as a drug target enzyme: insights from molecular docking and molecular dynamics.

Multiple antibiotic-resistant strains of can cause life-threatening infections. Bacterial enoyl-acyl carrier protein (ACP) reductases (ENRs) are considered critical targets for developing antibiotics. Our current study aims to identify inhibitors of ENRs (FabI and FabV).

Toxic effects of the anticancer drug epirubicin in vitro assayed in human erythrocytes.

Epirubicin is a cytotoxic drug used in the treatment of different types of cancer and increasing evidence suggests that its target is cell membranes. In order to gain insight on its toxic effects, intact red blood cells (RBC), human erythrocyte membranes and molecular models were used. The latter consisted in bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), phospholipid classes found mainly in the outer and inner monolayers of the human erythrocyte membrane, respectively.

Characterization of a new molecule capable of inhibiting several steps of the amyloid cascade in Alzheimer's disease.

Introduction: Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder in elderly people. Existent therapies are directed at alleviating some symptoms, but are not effective in altering the course of the disease.

Methods: Based on our previous study that showed that an Aβ-interacting small peptide protected against the toxic effects of amyloid-beta peptide (Aβ), we carried out an array of in silico, in vitro, and in vivo assays to identify a molecule having neuroprotective properties.

An in vitro study on the interaction of the anti-Alzheimer drug rivastigmine with human erythrocytes.

The inhibition of the enzyme acetylcholinesterase (AChE) is a frequently used therapeutic option to treat Alzheimer's disease (AD). By decreasing the levels of acetylcholine degradation in the synaptic space, some cognitive functions of patients suffering from this disease are significantly improved. Rivastigmine is one of the most widely used AChE inhibitors.

The acetylcholinesterase (AChE) inhibitor and anti-Alzheimer drug donepezil interacts with human erythrocytes.

Donepezil is used to treat symptomatically the Alzheimer's disease (AD). This drug is a specific inhibitor of the enzyme acetylcholinesterase (AChE), whose main physiological function is to hydrolyze the neurotransmitter acetylcholine. The main objective of this work was to study the effect of donepezil on human erythrocytes as AChE is present in its membrane.

In vitro antioxidant and antiproliferative effect of the extracts of Ephedra chilensis K Presl aerial parts.

Background: Ephedra chilensis K Presl, known locally as pingo-pingo, is a Chilean endemic plant used in traditional medicine as an anti-inflammatory and used in other treatments. However, unlike for the other Ephedra species, there have been no reports on the antioxidant and cytotoxic effects of this plant. The present study aims to explore the potential applications of E.

Case Report: Hemothorax in Envenomation by the Viperid Snake .

, a highly venomous pit viper distributed from Colombia and northwestern Peru in South America to southern Mexico, is responsible for most snake bites in Central America, affecting especially young agricultural workers. A 17-year-old male from a rural area in northern Honduras was admitted at San Francisco Hospital after a bite that had occurred 3 days earlier. The puncture wounds were located on the first toe of the right foot.

An in vitro study of the protective effect of caffeic acid on human erythrocytes.

The interaction and protective effect of caffeic acid (CA) on human erythrocytes (RBC) and molecular models of its membrane were studied. The latter consisted of bilayers built up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representative of phospholipid classes located in the outer and inner monolayers of the human erythrocyte membrane, respectively. X-ray diffraction and differential scanning calorimetry results indicated that CA induced structural and thermotropic perturbations in multilayers and vesicles of DMPC.

Protective effect of epigallocatechin gallate on human erythrocytes.

The interactions and the protective effect of epigallocatechin gallate (EGCG) on human erythrocytes (RBC) and molecular models of its membrane were investigated. The latter consisted of bilayers built- up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representative of phospholipid classes located in the outer and inner monolayers of the human erythrocyte membrane, respectively. X-ray diffraction and differential scanning calorimetry experiments showed that EGCG induced significant structural and thermotropic perturbations in multilayers and vesicles of DMPC; however, these effects were not observed in DMPE.

In vitro effects of the antitumor drug miltefosine on human erythrocytes and molecular models of its membrane.

This study was aimed at elucidating the molecular mechanisms of the interaction of the antitumor alkylphospholipid drug miltefosine with human erythrocytes (RBC) and molecular models of its membrane. The latter consisted of bilayers of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representative of phospholipid classes located in the outer and inner monolayers of the human erythrocyte membrane, respectively. X-ray results showed that the drug interacted with DMPC multilayers; however, no effects on DMPE were detected.

Inhibitory effect of short cationic homopeptides against Gram-negative bacteria.

Previous work demonstrated that Lys homopeptides with an odd number of residues (9, 11 and 13) were capable of inhibiting the growth of Gram-positive bacteria in a broader spectrum and more efficiently than those with an even number of Lys residues or Arg homopeptides of the same size. Indeed, all Gram-positive bacteria tested were totally inhibited by 11-residue Lys homopeptides. In the present work, a wide variety of Gram-negative bacteria were used to evaluate the inhibitory activity of chemically synthesized homopeptides of L-Lys and L-Arg ranging from 7 to 14 residues.

Speciation analysis of organotin compounds in human urine by headspace solid-phase micro-extraction and gas chromatography with pulsed flame photometric detection.

A new headspace solid-phase micro-extraction (HS-SPME) method followed by gas chromatography with pulsed flame photometric detection (GC-PFPD) analysis has been developed for the simultaneous determination of 11 organotin compounds, including methyl-, butyl-, phenyl- and octyltin derivates, in human urine. The methodology has been validated by the analysis of urine samples fortified with all analytes at different concentration levels, and recovery rates above 87% and relative precisions between 2% and 7% were obtained. Additionally, an experimental-design approach has been used to model the storage stability of organotin compounds in human urine, demonstrating that organotins are highly degraded in this medium, although their stability is satisfactory during the first 4 days of storage at 4 °C and pH=4.

Differential dynamic and structural behavior of lipid-cholesterol domains in model membranes.

Changes in the cholesterol (Chol) content of biological membranes are known to alter the physicochemical properties of the lipid lamella and consequently the function of membrane-associated enzymes. To characterize these changes, we used steady-state and time resolved fluorescence spectroscopy and two photon-excitation microscopy techniques. The membrane systems were chosen according to the techniques that were used: large unilamellar vesicles (LUVs) for cuvette and giant unilamellar vesicles (GUVs) for microscopy measurements; they were prepared from dipalmitoyl phosphatidylcholine (DPPC) and dioctadecyl phosphatidylcholine (DOPC) in mixtures that are well known to form lipid domains.