Synthesis, Characterization, and Biological Evaluation of Chitosan Nanoparticles Cross-Linked with Phytic Acid and Loaded with Colistin against Extensively Drug-Resistant Bacteria.

The natural evolution of microorganisms, as well as the inappropriate use of medicines, have accelerated the problem of drug resistance to many of the antibiotics employed today. Colistin, a lipopeptide antibiotic used as a last resort against multi-resistant strains, has also begun to present these challenges. Therefore, this study was focused on establishing whether colistin associated with chitosan nanoparticles could improve its antibiotic activity on an extremely resistant clinical isolate of , which is a clinically relevant Gram-negative bacterium.

Biopolymers as a Potential Alternative for the Retention of Pollutants from Vinasse: An In Silico Approach.

Vinasse, a waste from the bioethanol industry, presents a crucial environmental challenge due to its high organic matter content, which is difficult to biodegrade. Currently, no sustainable alternatives are available for treating the amount of vinasse generated. Conversely, biopolymers such as cellulose, carboxymethylcellulose, and chitosan are emerging as an interesting alternative for vinasse control due to their flocculating capacity against several organic compounds.

Characterization and Classification In Silico of Peptides with Dual Activity (Antimicrobial and Wound Healing).

The growing challenge of chronic wounds and antibiotic resistance has spotlighted the potential of dual-function peptides (antimicrobial and wound healing) as novel therapeutic strategies. The investigation aimed to characterize and correlate in silico the physicochemical attributes of these peptides with their biological activity. We sourced a dataset of 207 such peptides from various peptide databases, followed by a detailed analysis of their physicochemical properties using bioinformatic tools.

Specific Focus on Antifungal Peptides against Azole Resistant : Current Status, Challenges, and Future Perspectives.

The prevalence of fungal infections is increasing worldwide, especially that of aspergillosis, which previously only affected people with immunosuppression. can cause allergic bronchopulmonary aspergillosis and endangers public health due to resistance to azole-type antimycotics such as fluconazole. Antifungal peptides are viable alternatives that combat infection by forming pores in membranes through electrostatic interactions with the phospholipids as well as cell death to peptides that inhibit protein synthesis and inhibit cell replication.

Integrating In Vitro and In Silico Analysis of a Cationic Antimicrobial Peptide Interaction with Model Membranes of Colistin-Resistant Strains.

Bacterial antibiotic resistance is a serious global public health concern. Infections caused by colistin-resistant (CRPa) strains represent a serious threat due to their considerable morbidity and mortality rates, since most of the current empirical antibiotic therapies are ineffective against these strains. Accordingly, cationic antimicrobial peptides (CAMPs) have emerged as promising alternatives to control resistant bacteria.

Development, Characterization, and Antimicrobial Evaluation of Ampicillin-Loaded Nanoparticles Based on Poly(maleic acid--vinylpyrrolidone) on Resistant Strains.

This study was focused on synthesizing, characterizing, and evaluating the antimicrobial effect of polymer nanoparticles (NPs) loaded with ampicillin. For this, the NPs were produced through polymeric self-assembly in aqueous media assisted by high-intensity sonication, using anionic polymers corresponding to the sodium salts of poly(maleic acid--vinylpyrrolidone) and poly(maleic acid--vinylpyrrolidone) modified with decyl-amine, here named as PMA-VP and PMA-VP-N10, respectively. The polymeric NPs were analyzed and characterized through the formation of polymeric pseudo-phases utilizing pyrene as fluorescent probe, as well as by measurements of particle size, zeta potential, polydispersity index, and encapsulation efficiency.

In Silico Characterization of the Interaction between the PBP2a "Decoy" Protein of Resistant and the Monomeric Units of Eudragit E-100 and Poly(Maleic Acid--Octadecene) Polymers.

Antimicrobial treatment alternatives for methicillin-resistant (MRSA) are increasingly limited. MRSA strains are resistant to methicillin due to the formation of β-lactamase enzymes, as well as the acquisition of the mecA gene, which encodes the penicillin-binding protein (PBP2a) that reduces the affinity for β-lactam drugs. Previous studies have shown that the use of ampicillin-loaded nanoparticles can improve antimicrobial activity on resistant strains.

In Vitro Evaluation of the Potential Pharmacological Activity and Molecular Targets of New Benzimidazole-Based Schiff Base Metal Complexes.

Metal-based drugs, including lanthanide complexes, have been extremely effective in clinical treatments against various diseases and have raised major interest in recent decades. Hence, in this work, a series of lanthanum (III) and cerium (III) complexes, including Schiff base ligands derived from (1-benzimidazol-2-yl)aniline, salicylaldehyde, and 2,4-dihydroxybenzaldehyde were synthesized and characterized using different spectroscopic methods. Besides their cytotoxic activities, they were examined in human U-937 cells, primate kidney non-cancerous COS-7, and six other, different human tumor cell lines: U251, PC-3, K562, HCT-15, MCF-7, and SK-LU-1.

A Study of the Interaction of a New Benzimidazole Schiff Base with Synthetic and Simulated Membrane Models of Bacterial and Mammalian Membranes.

Biological membranes are complex dynamic systems composed of a great variety of carbohydrates, lipids, and proteins, which together play a pivotal role in the protection of organisms and through which the interchange of different substances is regulated in the cell. Given the complexity of membranes, models mimicking them provide a convenient way to study and better understand their mechanisms of action and their interactions with biologically active compounds. Thus, in the present study, a new Schiff base () derivative from 2-(-aminophenyl)benzimidazole and 2,4-dihydroxybenzaldehyde was synthesized and characterized by spectroscopic and spectrometric techniques.

In Silico Selection and Evaluation of Pugnins with Antibacterial and Anticancer Activity Using Skin Transcriptome of Treefrog ().

In order to combat bacterial and cancer resistance, we identified peptides (pugnins) with dual antibacterial l-anticancer activity from the () skin transcriptome through in silico analysis. Pugnins A and B were selected owing to their high similarity to the DS4.3 peptide, which served as a template for their alignment to the transcriptome, as well as their function as part of a voltage-dependent potassium channel protein.

Validation by Molecular Dynamics of the Major Components of Sugarcane Vinasse, On a Surface of Calcium Carbonate (Calcite).

There is ongoing interest in the alcohol industry to significantly reduce and/or add value to the liquid residue, vinasse, produced after the distillation and rectification of ethanol from sugar cane. Vinasse contains potassium, glycerol, and a protein component that can cause environmental issues if improperly disposed of. Currently, some industries have optimized their processes to reduce waste, and a significant proportion of vinasse is being considered for use as an additive in other industrial processes.

Antimicrobial Contribution of Chitosan Surface-Modified Nanoliposomes Combined with Colistin against Sensitive and Colistin-Resistant Clinical .

Colistin is a re-emergent antibiotic peptide used as a last resort in clinical practice to overcome multi-drug resistant (MDR) Gram-negative bacterial infections. Unfortunately, the dissemination of colistin-resistant strains has increased in recent years and is considered a public health problem worldwide. Strategies to reduce resistance to antibiotics such as nanotechnology have been applied successfully.

In Silico Discovery of Antimicrobial Peptides as an Alternative to Control SARS-CoV-2.

A serious pandemic has been caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The interaction between spike surface viral protein (Sgp) and the angiotensin-converting enzyme 2 (ACE2) cellular receptor is essential to understand the SARS-CoV-2 infectivity and pathogenicity. Currently, no drugs are available to treat the infection caused by this coronavirus and the use of antimicrobial peptides (AMPs) may be a promising alternative therapeutic strategy to control SARS-CoV-2.

Development of Antioxidant-Loaded Nanoliposomes Employing Lecithins with Different Purity Grades.

This work focused on comparing the ability of lecithins with two purity grades regarding their performance in the development of nanoliposomes, as well as their ability to contain and release polar (trans-aconitic acid) and non-polar (quercetin) antioxidant compounds. First, the chemical characterization of both lecithins was carried out through infrared spectroscopy (FTIR), electrospray ionization mass spectrometry (ESI/MS), and modulated differential scanning calorimetry (mDSC). Second, nanoliposomes were prepared by the ethanol injection method and characterized by means of particle size, polydispersity, and zeta potential measurements.

Antibacterial Activity of a Cationic Antimicrobial Peptide against Multidrug-Resistant Gram-Negative Clinical Isolates and Their Potential Molecular Targets.

Antimicrobial resistance reduces the efficacy of antibiotics. Infections caused by multidrug-resistant (MDR), Gram-negative bacterial strains, such as (MDRKp) and (MDRPa), are a serious threat to global health. However, cationic antimicrobial peptides (CAMPs) are promising as an alternative therapeutic strategy against MDR strains.

Peptides with Dual Antimicrobial-Anticancer Activity: Strategies to Overcome Peptide Limitations and Rational Design of Anticancer Peptides.

Peptides are naturally produced by all organisms and exhibit a wide range of physiological, immunomodulatory, and wound healing functions. Furthermore, they can provide with protection against microorganisms and tumor cells. Their multifaceted performance, high selectivity, and reduced toxicity have positioned them as effective therapeutic agents, representing a positive economic impact for pharmaceutical companies.

A Novel Cecropin D-Derived Short Cationic Antimicrobial Peptide Exhibits Antibacterial Activity Against Wild-Type and Multidrug-Resistant Strains of and .

Infections caused by multidrug-resistant (MDR) and are a serious worldwide public health concern due to the ineffectiveness of empirical antibiotic therapy. Therefore, research and the development of new antibiotic alternatives are urgently needed to control these bacteria. The use of cationic antimicrobial peptides (CAMPs) is a promising candidate alternative therapeutic strategy to antibiotics because they exhibit antibacterial activity against both antibiotic susceptible and MDR strains.

Synthesis, biological evaluation and model membrane studies on metal complexes containing aromatic N,O-chelate ligands.

Novel lanthanide (Ln) compounds [Ln(L)]ClxHO (Ln = La, Ce, Sm) containing aromatic N,O-chelate ligands [HL1 = 4-amino-2-(1-benzimidazol-2-yl)phenol; HL2 = 5-amino-2-(1-benzimidazol-2-yl)phenol] have been synthesized and structurally characterized by elemental analysis, NMR and IR spectroscopy, molar conductance measurements, and mass spectrometry (MS). The spectroscopic data suggested that the benzimidazolyl-phenol ligands act as N,O-chelate ligands through the iminic nitrogen and phenolic oxygen atoms. Elemental analysis indicated that lanthanide compounds were formed in a 1:2 stoichiometry (metal:ligand).

Development of Polyelectrolyte Complex Nanoparticles-PECNs Loaded with Ampicillin by Means of Polyelectrolyte Complexation and Ultra-High Pressure Homogenization (UHPH).

This study was focused on synthesizing, characterizing and evaluating the biological potential of Polyelectrolyte Complex Nanoparticles (PECNs) loaded with the antibiotic ampicillin. For this, the PECNs were produced initially by polyelectrolytic complexation (bottom-up method) and subsequently subjected to ultra-high pressure homogenization-UHPH (top-down method). The synthetic polymeric materials corresponding to the sodium salt of poly(maleic acid--octadecene) (PAM-18Na) and the chloride salt of Eudragit E-100 (EuCl) were used, where the order of polyelectrolyte complexation, the polyelectrolyte ratio and the UHPH conditions on the PECNs features were evaluated.

Relationship between the Ionization Degree and the Inter-Polymeric Aggregation of the Poly(maleic acid--octadecene) Salts Regarding Time.

Alternating amphiphilic copolymers are macromolecular systems with a polarity duality in their structure, since they are generally formed by alternating segments corresponding to a potential electrolyte group and an alkyl (aliphatic or aromatic) group. These systems, depending on the ionization degree, as well as the time, may form different types of intra and interpolymeric aggregates in aqueous media. Therefore, this study, which in fact is the continuation of a previously reported work, is focused on establishing how the ionization degree of the sodium and potassium salts of the poly(maleic acid--octadecene) affect zeta potential, pH, electrical conductivity, particle size, polydispersity index, and surface tension over time.

Increases in Hydrophilicity and Charge on the Polar Face of Alyteserin 1c Helix Change its Selectivity towards Gram-Positive Bacteria.

Recently, resistance of pathogens towards conventional antibiotics has increased, representing a threat to public health globally. As part of the fight against this, studies on alternative antibiotics such as antimicrobial peptides have been performed, and it has been shown that their sequence and structure are closely related to their antimicrobial activity. Against this background, we here evaluated the antibacterial activity of two peptides developed by solid-phase synthesis, Alyteserin 1c (WT) and its mutant derivative (ΔM), which shows increased net charge and reduced hydrophobicity.

Synthesis, Characterisation and Biological Evaluation of Ampicillin-Chitosan-Polyanion Nanoparticles Produced by Ionic Gelation and Polyelectrolyte Complexation Assisted by High-Intensity Sonication.

Recently, one of the promising strategies to fight sensitive and resistant bacteria, and decrease the morbidity and mortality rates due to non-nosocomial infections, is to use antibiotic-loaded nanoparticles. In this study, ampicillin-loaded chitosan-polyanion nanoparticles were produced through the techniques of ionic gelation and polyelectrolyte complexation assisted by high-intensity sonication, using several crosslinking agents, including phytic acid (non-polymeric polyanion), sodium and potassium salts of poly(maleic acid--ethylene) and poly(maleic acid--octadecene) (polymeric polyanions). These nanoparticles were analysed and characterised in terms of particle size, polydispersity index, zeta potential and encapsulation efficiency.

Studies on the Interaction of Alyteserin 1c Peptide and Its Cationic Analogue with Model Membranes Imitating Mammalian and Bacterial Membranes.

Antimicrobial peptides (AMPs) are effector molecules of the innate immune system and have been isolated from multiple organisms. Their antimicrobial properties are due to the fact that they interact mainly with the anionic membrane of the microorganisms, permeabilizing it and releasing the cytoplasmic content. Alyteserin 1c (+2), an AMP isolated from and its more cationic and hydrophilic analogue (+5) were synthesized using the solid phase method, in order to study the interaction with model membranes by calorimetric and spectroscopic assays.

Evaluation of the Antimicrobial Activity of Cationic Peptides Loaded in Surface-Modified Nanoliposomes against Foodborne Bacteria.

Bacteria are a common group of foodborne pathogens presenting public health issues with a large economic burden for the food industry. Our work focused on a solution to this problem by evaluating antibiotic activity against two bacteria ( and ) of relevance in the field of foodstuffs. We used two approaches: structural modification of the antimicrobial peptides and nano-vehiculisation of the modified peptides into polymer-coated liposomes.

Decrease of Antimicrobial Resistance through Polyelectrolyte-Coated Nanoliposomes Loaded with β-Lactam Drug.

Currently, one of the greatest health challenges worldwide is the resistance to antibiotic drugs, which has led to the pursuit of new alternatives for the recovery of biological activity, where the use of different types of nano-systems has shown an interesting potential. In this study, we evaluated the antibiotic activity of a model drug (ampicillin) encapsulated within coated-nanoliposomes on strains of with different antibiotic-resistance degrees. Hence, liposomes were elaborated by the ethanol injection method and were coated with a cationic polymer (Eudragit E-100) through the layer-by-layer process.