Search Results (1,687)

The emergence of multidrug-resistant (MDR) bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA), represents a major global health challenge by limiting the current therapeutic options. In this context, antimicrobial peptides (AMPs) have been widely studied for their potent antimicrobial properties. In this study, we evaluated the anti-MRSA effect of a novel AMP, LyeTx I mnΔKL, derived from a toxin of Lycosa erythrognatha. Its activity was evaluated in vitro by minimal inhibitory and bactericidal concentrations (MIC and MBC), antibiofilm effect, membrane interaction, cytotoxicity, synergistic interaction with vancomycin, and in vivo in an MRSA murine wound/abscess infection model. LyeTx I mnΔKL showed enhanced antimicrobial activity against clinical MRSA isolates compared to its prototype (LyeTx I mnΔK), with MIC₅₀ and MBC₅₀ of 2 and 8 µM and 16 and 32 µM, respectively. Furthermore, LyeTx I mnΔKL exhibited a rapid bactericidal effect and a pronounced ability to inhibit biofilm formation and disrupt mature biofilms. LyeTx I mnΔKL interacts with bacterial membranes, adopts an α-helical structure, and induces membrane disruption and leakage of intracellular material. In vivo, topical treatment with LyeTx I mnΔKL reduced MRSA burden compared with LyeTx I mnΔK and untreated controls (log₁₀ CFU/g of wound of 2.4, 4.4, and 6.5 for LyeTx I mnΔKL, LyeTx I mnΔK, and the saline group, respectively). However, increased cytotoxicity remains a significant limitation. Overall, LyeTx I mnΔKL is a promising anti-MRSA candidate for topical use with potent antibiofilm and in vivo activity. Full article

Root nitrogen acquisition is a central belowground process that determines how efficiently plants capture nitrogen from the rhizosphere and influences fertilizer demand and environmental nitrogen losses. Root N transporters, including nitrate, ammonium, amino acid, and peptide transporters, provide the molecular basis for inorganic and organic N uptake. However, root N acquisition is not determined solely by plant transport systems but is also shaped by rhizosphere microbial communities that regulate N mobilization, transformation, and availability. In addition to bacteria and archaea, saprotrophic fungi and mycorrhizal associations contribute to organic matter decomposition, N mineralization, and symbiotic N transfer. Mechanistically, transporter activity may alter rhizosphere N gradients and substrate availability, while root exudates and microbial metabolites can influence microbial recruitment, root physiology, and transporter expression. Evidence from rice NRT1.1B and OsLHT1 suggests that specific N transporter genes can influence rhizosphere microbiome assembly, although direct genetic evidence remains limited to a small number of transporter systems and crop contexts. This review synthesizes current knowledge on root N transporter diversity, rhizosphere microbial N cycling, organic N availability, and transporter–microbiome feedbacks in root-level N acquisition. By integrating plant physiology, soil microbiology, and rhizosphere ecology, this review proposes a conceptual framework in which root N transporters and microbial communities act as interconnected components of belowground N acquisition. Future integration of transporter-informed breeding, microbiome management, and fertilization strategies may improve root N capture while reducing reliance on synthetic N inputs. Full article

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal malignancy lacking non-invasive functional diagnostic tools. The objective of this study was to develop and analytically validate a qualitative chromogenic urine assay (Panuri) detecting proteolytic activity associated with pancreatic cancer. Methods: This study reports on the analytical validation of a prototype configuration of the Panuri assay. The assay is based on enzymatic hydrolysis of synthetic peptide substrates measured spectrophotometrically at 410 nm. Results were interpreted qualitatively using predefined OD/h cut-off values (R1: 0.002206; R2: 0.003343; R3: 0.000766). Analytical validation included determination of sensitivity and specificity, precision assessment, and interference testing with microorganisms (10⁷ CFU/mL) and selected endogenous substances. Results: At the established OD/h cut-off, the assay demonstrated 89% sensitivity (95% CI: 78.5–94.9%) and 75% specificity (95% CI: 64.8–83.5%). Precision studies demonstrated repeatability, within-laboratory precision, and inter-laboratory reproducibility, with coefficients of variation below 10%. Interference from endogenous substances was limited under testing conditions, whereas high microbial contamination induced classification shifts. Further analytical studies are ongoing to assess the impact of exogenous interferents, including drugs and supplements, in accordance with extended interference evaluation requirements. Conclusions: The Panuri assay demonstrates predefined analytical performance characteristics for qualitative detection of proteolytic activity in the urine under the conditions evaluated in this study. Full article

The cysteine-based thiol–epoxy ‘click’ reaction is demonstrated as an efficient and practical approach for the synthesis of zwitterionic structures. The transformation employs unprotected cysteine, proceeds in aqueous media, and affords quantitative conversions. Notably, acid- and base-catalyzed conditions provide exclusive access to different cysteine-based thioether regioisomers in aqueous conditions. The pH-responsive behavior of the resulting zwitterions is further elucidated by NMR spectroscopy. Finally, the synthetic strategy is extended to the preparation of cysteine- and glutathione-functionalized polyethylene glycol polymers, showcasing its utility for the preparation of amino acid-/peptide-containing macromolecular materials. Full article

Objectives: AC02, a novel synthetic peptide derived from ACTH, is being developed as a potential therapeutic alternative to porcine ACTH_1-39 for use in infantile spasms. Methods: The study comprised single-ascending dose cohorts (0.02, 0.04, 0.08, 0.16 mg/kg AC02) and multiple-ascending dose cohorts (0.04, 0.08 mg/kg AC02 daily for 5 days). A separate positive-control arm received porcine ACTH_1-39 (25 U/day for 5 days). PD effects (free and total cortisol) were compared head-to-head with the positive control. Plasma concentrations of AC02, porcine ACTH_1-39, free and total cortisol were quantified by validated LC-MS/MS methods, and anti-drug antibody responses were measured using a validated electrochemiluminescence bridging immunoassay. Population PK/PD modeling characterized the concentration–response relationships for free cortisol. Results: Across the 0.02–0.16 mg/kg dose range, AC02 exhibited approximately dose-proportional pharmacokinetics and no accumulation after multiple doses. At 0.04 and 0.08 mg/kg, the baseline-corrected effects on free cortisol were generally consistent with those of porcine ACTH_1-39. Dynamic monitoring of the free cortisol fraction revealed a biphasic pattern across all groups: an early peak followed by a later rise. Total cortisol, by contrast, showed only a monophasic decline, indicating the limitations of total cortisol as a sole PD biomarker. No unexpected safety signals were observed. At 0.04 mg/kg, AC02 demonstrated pharmacodynamic responses comparable to those of marketed ACTH product based on the biologically active component of free cortisol, with favorable safety and pharmacokinetic profiles. Conclusions: This first-in-human study demonstrates that AC02 has favorable pharmacokinetic properties, and an acceptable safety profile. Full article

Background/Objectives: Microcapsules are particles 1–1000 µm in size, with a core containing the active substance (in liquid, solid, or gaseous state) and a shell typically composed of natural, synthetic, or semi-synthetic polymers. Although natural polymer-based microcapsules have applications in food, cosmetics, and other industries, this review primarily focuses on their role in pharmaceutical drug delivery. In recent years, natural macromolecules have gained increasing attention as coating materials due to their biocompatibility, biodegradability, low toxicity, mucoadhesive properties, and ability to enable controlled and targeted drug release. Based on previous research, this review provides an overview of microcapsules, the most common microencapsulation methods, natural polymers used as wall materials, and their pharmaceutical applications across different routes of administration. Results: By encapsulating active ingredients, microcapsules enhance their bioavailability, prolong their release, protect them, enable targeted delivery, and mask unpleasant tastes and odors. Among the most commonly used microencapsulation techniques are physical methods (spray drying, spray cooling, solvent evaporation, spray coating, and freeze drying) and physicochemical methods (coacervation). Natural polymers, particularly polysaccharides and proteins, have been successfully used in oral, topical, transdermal, pulmonary, and colon-targeted drug delivery systems, as well as for the stabilization and delivery of peptides, proteins, probiotics, and vaccines. Conclusions: Proper selection of microencapsulation technique depends on the properties of the polymer and the core material. Natural polymers represent versatile pharmaceutical excipients owing to their biocompatibility, biodegradability, safety, mucoadhesive behavior, and ability to provide controlled and targeted drug delivery. Their successful application with a wide range of therapeutic agents and administration routes highlights their considerable potential for the development of advanced drug delivery systems. Full article

The amide functional group remains a cornerstone of medicinal chemistry, serving as an indispensable scaffold in the design of modern therapeutics. This review presents an analysis of FDA-approved drugs (small molecules and peptides with MW < 1300 Da) containing amide functionality between 2021 and 2025, highlighting its continued and evolving role in addressing contemporary medical challenges. An analysis of these novel therapeutics reveals the remarkable functional versatility of the amide bond. In antiviral agents like nirmatrelvir (Paxlovid^®), amides form the structural backbone of peptidomimetics, enabling high-affinity binding to a viral protease. In precision oncology, as seen with adagrasib (Krazati^®), the amide acts as a critical, metabolically stable linker that positions a covalent warhead for selective inhibition of a mutant kinase. This analysis underscores that amide’s unique combination of planarity, resonance stabilization, and capacity for robust hydrogen bonding continues to make it an essential element in the medicinal chemist’s toolkit, underpinning the development of next-generation therapeutics across oncology, infectious diseases, and neurology. To provide a practical framework for drug discovery, the synthetic routes for each drug are detailed, with particular emphasis placed on the key amide-forming strategies employed. Full article

Peptide purification by preparative reversed-phase liquid chromatography remains one of the most resource-intensive stages in synthetic peptide manufacturing. Production processes commonly rely on acetonitrile/trifluoroacetic acid (ACN/TFA) mobile phases mainly because of their high chromatographic resolution. However, both components raise significant environmental and safety concerns related to toxicity, flammability, waste generation, and, in the case of TFA, environmental persistence as a per- and polyfluoroalkyl substance (PFAS, known as a “forever chemical”). Green alternatives based on ethanol, dimethyl carbonate, and sustainable acidic additives such as acetic acid have been proposed, but their industrial adoption remains limited due to reduced chromatographic performance, often resulting in lower yield and productivity under conventional batch operation. In this work, multi-column counter-current solvent gradient purification (MCSGP) was investigated as a strategy to integrate the use of green eluent systems without compromising process performance. Two therapeutic peptides, Tirzepatide and Tetracosactide, were selected as representative case studies with different structural complexity. Using ethanol/acetic acid for Tirzepatide and dimethyl carbonate/acetic acid for Tetracosactide, the MCSGP process achieved purity levels equivalent to those obtained with conventional ACN/TFA batch chromatography, with 88.1% yield at 89.0% purity for Tirzepatide and 93.8% yield at 94.0% purity for Tetracosactide. Productivity for Tirzepatide was improved, reaching 6.3 g/L_resin/h. These results demonstrate that MCSGP can compensate for the reduced separation efficiency typically associated with green eluent systems, enabling sustainable peptide purification without compromising process performance. By combining green solvents with the MCSGP process, this work paves the way for more sustainable peptide purification processes while maintaining high yield and productivity. Full article

Retroviruses induce immunosuppression in their infected hosts. This phenomenon is well described for the immunodeficiency viruses, with human immunodeficiency virus type 1 (HIV-1) representing the best-studied example, but it also occurs in other retroviral infections. Immunosuppressive properties were first characterized in murine leukemia viruses (MuLV). Additional well-studied examples include feline leukemia virus (FeLV) and koala retrovirus (KoRV). Investigations into the mechanisms underlying retrovirus-induced immunosuppression revealed that not only inactivated viral particles but also their purified transmembrane (TM) envelope proteins exhibit immunosuppressive activity. However, in certain retroviral infections, additional viral proteins contribute to the immunosuppression in vivo. Within the TM envelope proteins, a highly conserved region—designated the immunosuppressive (isu) domain—was identified. Synthetic peptides corresponding to this domain suppress a wide range of in vitro immune responses, possibly by regulating Ras-Raf-MEK-MAPK and PI3K-AKT-mTOR pathways. They modulate cytokine release and alter gene expression in immune cells, mirroring the activity of the corresponding TM envelope protein. Mutations in the sequence abrogate the effect. Numerous TM envelope proteins have demonstrated immunosuppressive activity in vivo in a tumor rejection model, and mutations within the isu domain also abrogate this function. These studies have important implications for reproduction, particularly through the immunosuppressive syncytins in the placenta, for tumor development, where similar mechanisms may protect cancer cells from the host immune system, and for vaccine development and xenotransplantation. Notably, immunization with TM envelope proteins carrying mutations in the isu domain elicits stronger immune responses compared with the wild-type proteins. Finally, the potential of retroviral TM envelope proteins to protect xenotransplants from immune rejection will be discussed. Full article

Bioactive peptides (BPs) are widely distributed and exhibit remarkable physiological activities. However, their natural forms are frequently characterized by short half-lives, low membrane permeability, poor stability, and inadequate oral bioavailability, which severely limit their applications in the food, pharmaceutical, and biomaterial fields. Therefore, modification and engineering of natural BPs are essential to surmount these inherent limitations. Synthetic biology-based modification strategies, including amino acid substitution, sequence truncation and hybridization, side-chain functionalization, and main-chain/side-chain integration, are comprehensively summarized in this review. Chemical modification strategies, such as terminal modification, cyclization, backbone modification, polymer conjugation, lipidation, and glycosylation, are also discussed, with particular attention to their advantages, potential drawbacks, and practical limitations. Based on 122 studies identified through systematic literature searches across major scientific databases, this review also discusses the current challenges and future trends in BP modification, providing theoretical guidance and innovative insights for the further development and enhanced utilization of BPs. Full article

Selective insertion of lipid probes from the external milieu into raft regions of the cell membrane would enable targeted studies of raft molecular organization and of raft-associated peptide and glycan components. In this work, we compared the insertion of several synthetic glycolipids into raft and non-raft membrane areas of Raji and EA.hy 926 endothelial cells. A glyco-cholesterol derivative in which the 3β oxygen atom is replaced by NH was selected as a candidate raft-selective probe. Although this glycolipid also inserted into other membrane areas, its raft-to-non-raft distribution ratio was higher than that of its O-analog (natural 3β-O-cholesterol). Full article

Peptide therapeutics offer high target selectivity and low toxicity, but their clinical utility remains constrained by rapid proteolysis in vivo and negligible oral bioavailability. Incorporating non-canonical amino acids (ncAAs) provides a robust molecular engineering framework to overcome these pharmacokinetic bottlenecks. This review analyzes the structural and biophysical design rules of ncAA-mediated peptide stabilization, categorizing them into side-chain steric shielding, backbone conformational constraint, and stereochemical evasion of L-specific proteases. We systematically evaluate the biosynthetic milestones enabling this field, focusing on engineered orthogonal translation systems (tRNA/synthetase pairs, orthogonal ribosomes, quadruplet codons) and metabolic engineering strategies that supply fluorinated and other ncAA precursors de novo. Furthermore, we examine the translation of these technologies into clinical candidates (e.g., modified antimicrobial peptides, antibody–drug conjugates, and PROTACs) and identify scaling, immunogenicity, and computational modeling as key bottlenecks. This review serves as a technical reference for designing next-generation, hyper-stable peptide therapeutics. Full article

Agronomic biofortification represents an effective strategy to counteract hidden hunger in humans. Salts and synthetic chelates are widely used as foliar or root applications for enriching vegetables with mineral nutrients. Recently, biochelates have been proposed as a sustainable alternative to synthetic chelates, especially peptide-based biochelates that combine the beneficial role of peptides as biostimulants and chelating agents. This study investigated the impact of multiple foliar applications of two peptide-based biochelates for enhancing Fe and Zn in leaves of hydroponically grown lettuce. No significant differences were observed in the fresh and dry weight of lettuce shoots, leaf pigments, leaf antioxidant activity and leaf macronutrient profile, while a significant increase in biochelate treatments was observed in leaf Fe and Zn concentrations in comparison with untreated control (+38.1% and +44.1%, respectively). Leaf concentration of Fe and Zn in biochelate treatments allowed to estimate that 100 g of biofortified fresh lettuce shoots per day in the human diet can contribute to Population Reference Intake from 7.9 to 11.5% for Fe and from 3.3 to 3.9% for Zn. Moreover, Zn-peptide treatments reduced nitrate concentration with respect to control and Fe-peptide (−9% and −11%, respectively), increasing the quality of lettuce leaves. Overall, peptide-based biochelates proved to be a promising, environmentally friendly fertilizer for lettuce biofortification, enhancing Fe and Zn concentration without impairing yield and leaf quality. Full article

The increasing demand for sustainable crop protection strategies has intensified interest in plant-beneficial bacteria as alternatives to synthetic agrochemicals. In this study, the soil-derived bacterium Pseudomonas putida V01 was isolated and characterized for its antifungal and plant growth-promoting potential through an integrated approach combining biological assays, untargeted metabolomics, and in vivo plant experiments. Cell-free culture filtrates exhibited strong antifungal activity against major phytopathogenic fungi, completely inhibiting the growth of Sclerotium rolfsii and significantly reducing mycelial development of Alternaria alternata and Fusarium proliferatum by 40% and 20%, respectively. Volatile organic compounds (VOCs) selectively inhibited Botrytis cinerea and A. alternata by 28% and 10%, respectively, and affected sporulation of F. proliferatum. Metabolomic profiling through LC-qTOF-MS and GC-MS analyses revealed a chemically diverse metabolome, including putatively annotated diketopiperazines, cyclic peptides, phenolic compounds, and fatty acids. VOC profiling indicated ketones and alcohols as the predominant volatile classes, with 2-undecanone and 2-undecanol among the most abundant compounds detected. In vivo assays on wheat seedlings showed significant increases in shoot growth, biomass accumulation, and chlorophyll content compared with untreated controls. These findings indicate that P. putida V01 combines complementary antifungal and plant growth-promoting activities associated with a diverse repertoire of diffusible and volatile metabolites. The integrated biological and metabolomic characterization highlights its potential as a multifunctional microbial inoculant for sustainable crop production and disease management. Full article

Gold nanoparticles (AuNPs) have emerged as versatile antiviral nanoplatforms because their size, morphology, plasmonic properties, and surface chemistry can be precisely engineered. In this review, we summarize the core design principles of antiviral AuNPs from a structure–function–mechanism perspective. We first outline representative synthetic and interface-programming routes for AuNP preparation, including citrate reduction, Brust–Schiffrin synthesis, seed-mediated growth, green synthesis, direct thiol-conjugation, and mixed-ligand shell strategies, emphasizing how these approaches define particle size, morphology, surface accessibility, interfacial composition, and downstream biofunctionalization potential. We then discuss major surface engineering strategies, including polyethylene glycol, nucleic acids, antibodies and nanobodies, peptides, glycans, antiviral drugs, and biomimetic coatings, with particular attention to how ligand density, orientation, flexibility, and interfacial stability determine biological performance. Next, we examine how functionalized AuNPs inhibit different stages of the viral life cycle, including viral attachment and entry, intracellular replication, assembly and egress, photothermal inactivation, and immune modulation or vaccine delivery. Finally, we highlight current challenges, including incomplete structure–activity relationships, dynamic nano–bio interactions under physiological conditions, limited standardization across studies, and translational barriers related to safety, reproducibility, and scale-up. This review provides a conceptual framework for the rational development of next-generation AuNP-based antiviral nanotherapeutics. Full article