Eduardo Festozo Vicente

Fusion peptides within the coronavirus (CoV) Spike glycoprotein interact with host membranes and contribute to the structural rearrangements required for membrane fusion. Here, we investigated the upstream fusion peptide (FP_u) from severe acute respiratory syndrome (SARS)-CoV and the conserved internal fusion peptide (IFP) of SARS-CoV/SARS-CoV-2 in zwitterionic and anionic lysolipid micelles using steady-state and time-resolved fluorescence, circular dichroism (CD), electron spin resonance (ESR), and molecular dynamics (MD) simulations. Both peptides strongly associated with the micellar phase, with IFP displaying higher partition coefficients and a clearer preference for negatively charged micelles. FP_u exhibited pronounced environment-sensitive fluorescence changes, whereas CD revealed greater α-helical propensity for IFP and higher conformational heterogeneity for FP_u. ESR showed that both peptides restricted spin-probe rotational dynamics, with broader and stronger effects in anionic micelles, particularly under acidic pH. MD simulations further indicated dynamic micelle-bound topologies in which central peptide regions were preferentially lipid-associated and less solvent-exposed, while terminal regions remained more flexible. Together, the results demonstrate that peptide affinity, conformation, bound-state topology, and perturbation of micellar dynamics are related but non-equivalent properties, highlighting the importance of membrane composition and environmental conditions in modulating coronavirus fusion-peptide interactions.

Cationic antimicrobial peptides are promising candidates to combat antifungal resistance. However, a detailed understanding of their membranotropic activity is required for targeted applications and sequence engineering. Here, we investigated the native peptide Ctx(Ile21)-Ha, derived from the Brazilian Cerrado tree frog Boana albopunctata, and its analogues site-specifically labeled with the paramagnetic amino acid TOAC (2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid). Peptide interactions with biomimetic monolayers and liposomes mimicking human, fungal, and bacterial membranes were investigated using Langmuir monolayers, circular dichroism, and electron spin resonance (ESR). Anionic lipids, particularly palmitoyl-oleoyl-phosphatidylglycerol (POPG) and palmitoyl-oleoyl-phosphatidylserine (POPS), strongly enhanced peptide penetration into lipid monolayers and promoted substantial α-helical folding in large unilamellar vesicles (LUVs). The distinct monolayer responses of POPG- and POPS-containing membranes, despite their comparable α-helical contents, indicate that anionic headgroup chemistry modulates peptide–membrane interactions beyond electrostatic attraction. Conversely, cholesterol and ergosterol reduced peptide penetration and attenuated membrane-induced helix formation due to sterol-induced membrane packing. Site-directed ESR revealed lipid-dependent motional regimes for [TOAC2]Ctx(Ile21)-Ha and [TOAC13]Ctx(Ile21)-Ha, with the central region of the peptide becoming substantially more immobilized than the N-terminus upon membrane interaction. CD-derived membrane-association isotherms further showed that anionic membranes favor the coupled association/folding response, whereas comparison across the complementary techniques indicates that membrane association, peptide folding, and membrane penetration are mechanistically related but distinct steps in peptide–membrane interactions. Overall, the membrane activity of Ctx(Ile21)-Ha is best described as a charge- and packing-modulated process, in which electrostatic interactions favor peptide binding and folding, whereas membrane order modulates membrane penetration and local peptide dynamics.

This exploratory proof-of-concept study evaluated the physiological tolerability and performance of laying hens fed the microencapsulated antimicrobial peptide Ctx(Ile²¹)-Ha under severe heat stress (34.5 °C; THI = 85.3). Eighteen 40-week-old hens were evaluated in a 2 × 3 factorial design comprising two thermal environments (comfort: 26 °C; heat stress: 35 °C) and three peptide doses (0.0, 2.5, and 5.0 mg/kg feed). The peptide was synthesized (>95% purity) and microencapsulated by ionotropic gelation, exhibiting controlled in vitro intestinal release. Heat stress significantly reduced feed intake and egg weight (p < 0.05) while increasing rectal temperature (p < 0.01), consistent with a biologically relevant thermal challenge. No temperature × dose interactions were observed for feed intake, egg weight, feed conversion, Haugh unit, albumen height, or blood biochemical parameters (p > 0.05). However, significant interactions were detected for eggshell quality parameters (p < 0.05). In conclusion, while dietary Ctx(Ile²¹)-Ha did not mitigate performance losses induced by heat stress, the absence of blood biochemical alterations supports its preliminary physiological tolerability under these experimental conditions. Due to the limited sample size (n = 3), these exploratory findings require cautious interpretation.

Aim: To map and synthesize the available scientific evidence on the relationship between chronic low back pain and sleep-related outcomes among agro-industrial and industrial workers exposed to high physical demands. Subject and methods: A scoping review was conducted following the Joanna Briggs Institute methodology and the PRISMA-ScR checklist. Searches were performed in PubMed/MEDLINE, Scopus, Web of Science, Embase, and LILACS for studies published between 2000 and 2025. Quantitative observational studies in Portuguese, English, or Spanish involving adult workers in industrial or agricultural settings were included. Results: Thirteen studies met the inclusion criteria, predominantly with cross-sectional designs from Brazil and the United States. Chronic low back pain was consistently associated with poorer sleep quality, increased daytime sleepiness, fatigue, and sleep fragmentation. No study utilized objective diagnostic tools, such as polysomnography, for obstructive sleep apnea; evidence relied exclusively on self-reported measures. Biomechanical overload and psychosocial factors were identified as key modulators of this relationship. Conclusion: There is a consistent association between chronic low back pain and sleep disturbances in high-demand occupational settings. However, the lack of longitudinal data and objective sleep apnea diagnoses remains a significant gap. Integrated occupational health strategies addressing musculoskeletal health and sleep as interdependent components are essential for worker health surveillance.

Exceptionally, this space is now dedicated to a tribute to Prof. Dr. Danilo Florentino Pereira (in memoriam), who passed away on 30 May 2026, during the organization period for the Special Issue “Application of Antimicrobial Peptides and Natural Products as Feed Additives in Animal Production” of the journal Agriculture, in which he was contributing as a Guest Editor

Heavy metal contamination of water by cadmium (Cd²⁺) and silver (Ag⁺) represents a significant environmental concern due to their toxicity and persistence. In this study, peptide-functionalized resins were evaluated as bio-inspired adsorbent materials for metal removal from aqueous solutions. Glycine-based and histidine-containing peptide sequences were synthesized via solid-phase peptide synthesis and immobilized onto Wang and Rink amide resins, with and without N-terminal acetylation. Adsorption capacity (Q, mg g⁻¹) was determined for each material. The results showed that adsorption performance strongly depends on both peptide structure and metal type. Higher adsorption capacities were consistently observed for Cd²⁺ (up to 7.9 mg g⁻¹) compared to Ag⁺ (up to 2.4 mg g⁻¹). Interestingly, histidine-containing resins exhibited superior performance, likely due to the presence of imidazole groups that enhance metal coordination. In contrast, the influence of resin type and N-terminal acetylation was less consistent, suggesting a secondary role of these factors. Overall, the findings provide an initial screening or proof-of-concept for peptide-functionalized resins and highlight the potential of these peptidyl resins as effective adsorbent materials for the removal of heavy metals from aqueous environments.

Antimicrobial peptides such as Melittin exhibit potent broad-spectrum activity but are limited by high cytotoxicity. The rational design of bioinspired Melittin-derived analogues represents a promising strategy to reduce toxicity while maintaining antimicrobial efficacy. In this study, Melittin and analogues (TT-1, FKW, and WKW) were synthesized using solid-phase peptide synthesis (SPPS) and characterized for biological and biophysical essays. Antimicrobial and hemolytic activity, serum stability, secondary structure, and membrane interaction were analysed. FKW and WKW exhibited broad-spectrum antimicrobial activity, with minimum inhibitory concentration (MIC) as low as 8 and 16 µg/mL against Staphylococcus aureus and Enterococcus faecium. Both analogues also showed improved activity against Klebsiella pneumoniae (32 µg/mL) and Pseudomonas aeruginosa (128 and 256 µg/mL for FKW and WKW, respectively) compared to Melittin (64 and 512 µg/mL). In terms of cytotoxicity, FKW and WKW showed significantly reduced hemolytic activity, with HC₅₀ values of 264.8 µg/mL and 237.2 µg/mL, respectively, resulting in improved selectivity indexes relative to Melittin (HC₅₀ of 7.9 µg/mL). In liposomes, both adopt α-helical structures and cause disruption via pore formation or detergent-like mechanisms. TT-1 showed minimal toxicity but weak antimicrobial activity (MIC > 256 µg/mL). Although FKW and WKW exhibited limited serum stability (half-lives of 2.2 and 1.5 h), their degradation may reduce systemic toxicity. Overall, these analogues demonstrate an improved balance between antimicrobial activity and safety.