The alarming rise in antimicrobial resistance (AMR) has created a significant public health challenge, necessitating the discovery of new therapeutic agents to combat infectious diseases and oxidative stress-related disorders. The Lentzea flaviverrucosa strain E25-2, isolated from Moroccan forest soil, represents a potential avenue for such research. This study aimed to identify the isolate E25-2, obtained from soil in a cold Moroccan ecosystem, and further investigate its antimicrobial and antioxidant activities. Phylogenetic analysis based on 16S rRNA gene sequences revealed the strain\'s classification within the Lentzea genus, with a sequence closely resembling that of Lentzea flaviverrucosa AS4.0578 (96.10% similarity). Antimicrobial activity in solid media showed moderate to strong activity against Staphylococcus aureus ATCC 25923, Bacillus cereus strain ATCC 14579, Escherichia coli strain ATCC 25922, Candida albicans strain ATCC 60193 and 4 phytopathogenic fungi. In addition, ethyl acetate extract of this isolate demonstrated potent antimicrobial activity against 7 clinically multi-drug resistant bacteria. Furthermore, it demonstrated antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2\'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals, as well as a significant increase in ferric reducing antioxidant power. A significant positive correlation was observed between antioxidant activities and total content of phenolic compounds (p < 0.0001), along with flavonoids (p < 0.0001). Furthermore, gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of amines, hydroxyl groups, pyridopyrazinone rings, esters and pyrrolopyrazines. The Lentzea genus could offer promising prospects in the fight against antibiotic resistance and in the prevention against oxidative stress related diseases.

Streptococcus intermedius secretes the human-specific cytolysin intermedilysin (ILY), a crucial factor in the pathogenicity of this bacterium. Previously, we reported that a lactose phosphotransferase repressor (LacR) represses ily expression and that its mutation increases ILY production. Interestingly, UNS40, a strain isolated from a liver abscess, produces high levels of ILY despite the absence of mutations in the lacR promoter and coding regions. Our results showed that a G > A mutation at the - 90th position from the transcription start point in the UNS40 ily promoter region increased hemolytic activity and decreased the binding ability to LacR. To elucidate the regions involved in the repression of ily expression, we generated mutant strains, in which point or deletion mutations were introduced into the ily promoter region, and then compared their hemolytic activity. Among the point mutations, -120 C > A and -90 G > A and their flanking mutations increased hemolytic activity. These results indicated that these mutations may increase the virulence of S. intermedius.

The present study focused on evaluating the antibacterial properties, radical scavenging, and photocatalytic activities of Centaurea behen-mediated silver nanoparticles (Cb-AgNPs). The formation of Cb-AgNPs was approved by UV-Vis spectrometry, Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction. The results showed that the obtained AgNPs have a maximum absorbance peak at 450 nm with spherical morphology and an average size of 13.03 ± 5.8 nm. The catalytic activity of the Cb-AgNPs was investigated using Safranin O (SO) solution as a cationic dye model. The Cb-AgNPs performed well in the removal of SO. The coupled physical adsorption/photocatalysis reaction calculated about 68% and 98% degradation of SO dye under solar irradiation. The Cb-AgNPs inhibited the growth of gram-negative or positive bacteria strains and had excellent DPPH radicals scavenging ability (100% in a concentration of 200 µg/ml) as well as a good effect on reducing coagulation time (at concentrations of 200 and 500 µg/mL reduced clotting time up to 3 min). Considering the fact that green synthesized Cb-AgNPs have antioxidant and antibacterial properties and have a good ability to reduce coagulation time, they can be used in wound dressings. As well as these NPs with good photocatalytic activity can be a suitable option for degrading organic pollutants.

This study represents an advancement in the field of composite material engineering, focusing on the synthesis of composite materials derived from porous hydroxyapatite via surface modification employing cucurbit[n]urils, which are highly promising macrocyclic compounds. The surface modification procedure entailed the application of cucurbit[n]urils in an aqueous medium onto the hydroxyapatite surface. A comprehensive characterization of the resulting materials was undertaken, employing analytical techniques including infrared (IR) spectroscopy and scanning electron microscopy (SEM). Subsequently, the materials were subjected to rigorous evaluation for their hemolytic effect, anti-inflammatory properties, and cytotoxicity. Remarkably, the findings revealed a notable absence of typical hemolytic effects in materials incorporating surface-bound cucurbit[n]urils. This observation underscores the potential of these modified materials as biocompatible alternatives. Notably, this discovery presents a promising avenue for the fabrication of resilient and efficient biocomposites, offering a viable alternative to conventional approaches. Furthermore, these findings hint at the prospect of employing supramolecular strategies involving encapsulated cucurbit[n]urils in analogous processes. This suggests a novel direction for further research, potentially unlocking new frontiers in material engineering through the exploitation of supramolecular interactions.

The ESKAPE pathogen-associated antimicrobial resistance is a global public health issue, and novel therapeutic strategies are urgently needed. The short cationic antimicrobial peptide (AMP) family represents an important subfamily of scorpion-derived AMPs, but high hemolysis and poor antimicrobial activity hinder their therapeutic application. Here, we recomposed the hydrophilic face of Ctriporin through lysine substitution. We observed non-linear correlations between the physiochemical properties of the peptides and their activities, and significant deviations regarding the changes of antimicrobial activities against different bacterial species, as well as hemolytic activity. Most importantly, we obtained two Ctriporin analogs, CM5 and CM6, these two have significantly reduced hemolytic activity and more potent antimicrobial activities against all tested antibiotic-resistant ESKAPE pathogens. Fluorescence experiments indicated they may perform the bactericidal function through a membrane-lytic action model. Our work sheds light on the potential of CM5 and CM6 in developing novel antimicrobials and gives clues for optimizing peptides from the short cationic AMP family.

Saponins are glycosides widely distributed in the plant kingdom and have many pharmacological activities. However, their tendency to bind to cell membranes can cause cell rupture, limiting their clinical use. In the previous study, aristatoside C and davisianoside B were isolated from Cephalaria species. Cytotoxicity assays showed that they are more active on A-549 cell lines than doxorubicin but caused hemolysis. In the current research, aristatoside C and davisianoside B were loaded to phytosomes called ALPs and DLPs respectively, and characterized for particle size, zeta potential, encapsulation efficiency, release kinetic, hemolytic activity, and cytotoxicity on A-549 cell line. DLPs maintained the cytotoxic activity of the free saponins against A-549 cells with IC50 of 9,64±0,02 μg/ml but dramatically reduced their hemolytic activity. Furthermore, temperature and time-dependent stability studies based on the size and zeta potential of ALPs and DLPs revealed that the phytosomes have sustained release properties over 2 weeks. Overall, DLPs displayed cytotoxicity against A-549 cells with minimal hemolysis and sustained release, highlighting their potential as nanotherapeutics for clinical applications.

OBJECTIVE: Microbial cells capability to tolerate the effect of various antimicrobial classes represent a major worldwide health concern. The flexible and multi-components nanocomposites have enhanced physicochemical characters with several improved properties. Thus, different biological activities of biosynthesized starch/silver-selenium nanocomposite (St/Ag-Se NC) were assessed.
METHODS: The St/Ag-Se NC was biosynthesized using Cladosporium cladosporioides CBS 174.62 (C. cladosporioides) strain. The shape and average particle size were investigated using scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM), respectively. On the other hand, the St/Ag-Se NC effect on two cancer cell lines and red blood cells (RBCs) was evaluated and its hydrogen peroxide (H2O2) scavenging effect was assessed. Moreover, its effects on various microbial species in both planktonic and biofilm growth forms were examined.
RESULTS: The St/Ag-Se NC was successfully biosynthesized with oval and spherical shape and a mean particle diameter of 67.87 nm as confirmed by the HR-TEM analysis. St/Ag-Se NC showed promising anticancer activity toward human colorectal carcinoma (HCT-116) and human breast cancer (MCF-7) cell lines where IC50 were 21.37 and 19.98 µg/ml, respectively. Similarly, little effect on RBCs was observed with low nanocomposite concentration. As well, the highest nanocomposite H2O2 scavenging activity (42.84%) was recorded at a concentration of 2 mg/ml. Additionally, Staphylococcus epidermidis (S. epidermidis) ATCC 12,228 and Candida albicans (C. albicans) ATCC 10,231 were the highly affected bacterial and fungal strains with minimum inhibitory concentrations (MICs) of 18.75 and 50 µg/ml, respectively. Moreover, the noticeable effect of St/Ag-Se NC on microbial biofilm was concentration dependent. A high biofilm suppression percentage, 87.5% and 68.05%, were recorded with S. epidermidis and Staphylococcus aureus (S. aureus) when exposed to 1 mg/ml and 0.5 mg/ml, respectively.
CONCLUSIONS: The biosynthesized St/Ag-Se NC showed excellent antioxidant activity, haemocompatibility, and anti-proliferative effect at low concentrations. Also, it exhibited promising antimicrobial and antibiofilm activities.

UNASSIGNED: Infections caused by pathogenic microorganisms have increased the need for hospital care and have thus represented a public health problem and a significant financial burden. Classical treatments consisting of traditional antibiotics face several challenges today. Anti-microbial peptides (AMPs) are a conserved characteristic of the innate immune response among different animal species to defend against pathogenic microorganisms.
UNASSIGNED: In this study, a new peptide sequence (mCHTL131-140) was designed using the in silico approach.
UNASSIGNED: Cathelicidin-2 (UniprotID: Q2IAL7) was used as a potential antimicrobial protein, and a novel 10 - 12 amino acids sequence AMP was designed using bioinformatics tools and the AMP databases. Then, the anti-bacterial, anti-biofilm, and anti-fungal properties of the peptide, as well as its hemolytic activity and cytotoxicity towards human fibroblast (HDF) cells, were investigated in vitro.
UNASSIGNED: Online bioinformatics tools indicated that the peptide sequence could have anti-bacterial, anti-viral, anti-fungal, and anti-biofilm properties with little hemolytic properties. The experimental tests confirmed that mCHTL131-140 exhibited the best anti-bacterial properties against Acinetobacter baumannii and had fair anti-fungal properties. Besides, it did not cause red blood cell lysis and showed no cytotoxicity towards HDF cells.
UNASSIGNED: In general, the designed peptide can be considered a promising AMP to control hospital-acquired infections by A. baumannii.

BACKGROUND: Mycobacterium abscessus, a fast-growing non-tuberculous mycobacterium, is an emerging opportunistic pathogen responsible for chronic bronchopulmonary infections in people with respiratory diseases such as cystic fibrosis (CF). Due to its intrinsic polyresistance to a wide range of antibiotics, most treatments for M. abscessus pulmonary infections are poorly effective. In this context, antimicrobial peptides (AMPs) active against bacterial strains and less prompt to cause resistance, represent a good alternative to conventional antibiotics. Herein, we evaluated the effect of three arenicin isoforms, possessing two or four Cysteines involved in one (Ar-1, Ar-2) or two disulfide bonds (Ar-3), on the in vitro growth of M. abscessus.
METHODS: The respective disulfide-free AMPs, were built by replacing the Cysteines with alpha-amino-n-butyric acid (Abu) residue. We evaluated the efficiency of the eight arenicin derivatives through their antimicrobial activity against M. abscessus strains, their cytotoxicity towards human cell lines, and their hemolytic activity on human erythrocytes. The mechanism of action of the Ar-1 peptide was further investigated through membrane permeabilization assay, electron microscopy, lipid insertion assay via surface pressure measurement, and the induction of resistance assay.
RESULTS: Our results demonstrated that Ar-1 was the safest peptide with no toxicity towards human cells and no hemolytic activity, and the most active against M. abscessus growth. Ar-1 acts by insertion into mycobacterial lipids, resulting in a rapid membranolytic effect that kills M. abscessus without induction of resistance.
CONCLUSIONS: Overall, the present study emphasized Ar-1 as a potential new alternative to conventional antibiotics in the treatment of CF-associated bacterial infection related to M. abscessus.

The toxicological impact of airborne polluting ultrafine particles (UFPs, also classified as nanoparticles with average sizes of less than 100 nm) is an emerging area of research pursuing a better understanding of the health hazards they pose to humans and other organisms. Hemolytic activity is a toxicity parameter that can be assessed quickly and easily to establish part of a nanoparticle\'s behavior once it reaches our circulatory system. However, it is exceedingly difficult to determine to what extent each of the nanoparticles present in the air is responsible for the detrimental effects exhibited. At the same time, current hemolytic assessment methodologies pose a series of limitations for the interpretation of results. An alternative is to synthesize nanoparticles that model selected typical types of UFPs in air pollution and evaluate their individual contributions to adverse health effects under a clinical assay of osmotic fragility. Here, we discuss evidence pointing out that the absence of hemolysis is not always a synonym for safety; exposure to model nanopollutants, even at low concentrations, is enough to increase erythrocyte susceptibility and dysfunction. A modified osmotic fragility assay in combination with a morphological inspection of the nanopollutant-erythrocyte interaction allows a richer interpretation of the exposure outcomes. Membrane-nanoparticle interplay has a leading role in the vulnerability observed. Therefore, future research in this line of work should pay special attention to the evaluation of the mechanisms that cause membrane damage.