Biology subjects

Vicente, E. F.

Publications and source records attributed to Vicente, E. F..

4 recordsLinked to original sources

bioRxiv2025

The role of N-terminal acetylation on biomolecular condensation

N-terminal acetylation (Nt-acetylation) is one of the most prevalent co-translational modifications in eukaryotes, affecting nearly 80% of the human proteome. Despite its ubiquity, the potential impact of this phenomenon on biomolecular condensation has been largely overlooked. Here, we uncover how this chemically subtle modification can exert broad and multifaceted control over phase behaviour, using Grh1, a Golgi-associated protein involved in stress-induced secretion in yeast, as a model system. We show that Nt-acetylation increases the saturation concentration for condensation, reduces droplet size and number, dampens pH sensitivity, weakens electrostatic contributions, and suppresses water dipolar relaxation within condensates, indicating reduced internal hydration and environmental responsiveness. These effects are accompanied by acetylation-dependent dimerisation and local structural changes, including a concentration-dependent gain in -helicity. Remarkably, co- condensation assays reveal that acetylated and non-acetylated forms of the same protein are only partially miscible, giving rise to core-shell architectures driven by differences in interfacial tension. Together, our findings highlight Nt-acetylation as a potent, generalizable regulator of condensate material properties, linking primary sequence chemistry to mesoscale organisation. Given its evolutionary conservation and prevalence across eukaryotic proteomes, Nt-acetylation may represent a widespread mechanism for modulating protein condensation in health and disease.

biophysics↗

bioRxiv2021

HPMCP-coated microcapsules containing the Ctx(Ile21)-Ha antimicrobial peptide reduces the mortality rate caused by resistant Salmonella Enteritidis in poultry

The constant use of synthetic antibiotics as growth promoters can cause great bacterial resistance in chicks. Consequently, the use of these drugs has been restricted in different countries. Antimicrobial peptides have gained relevance in recent years due to their minimal capacity for bacterial resistance and does not generate toxic residues that harm the environment and human health. In this work, Ctx(Ile21)-Ha antimicrobial peptide was employed, due to its previously reported largely antimicrobial potential, to evaluate its application effect in laying chicks challenged with Salmonella Enteritidis, resistant to nalidixic acid and spectinomycin. For this, Ctx(Ile21)-Ha was synthesized, microencapsulated and coated with hypromellose phthalate (HPMCP) to be release in the intestine. Two different doses (3.2 and 6.4 {micro}g of Ctx(Ile21)-Ha per kg of isoproteic and isoenergetic poultry feed) were included in the chicks food and administered for 28 days. Antimicrobial activity, effect and response as treatment were evaluated. Statistical results were analyzed in detail and indicate that the formulated Ctx(Ile21)-Ha peptide had a positive and significant effect in relation to the reduction of chick mortality. There was a significant difference in laying chick weight between the control and microencapsulation treatment groups as a function of time. Therefore, the microencapsulated Ctx(Ile21)-Ha antimicrobial peptide may be an interesting and promising option in the substitution of conventional antibiotics.

microbiology↗

bioRxiv2021

Application of HPMCAS-coated Ctx(Ile21)-Ha peptide microparticles as a potential use to prevent systemic infection caused by Salmonella Enteritidis in poultry

The transmission of Salmonella Enteritidis (SE) in poultry is most often by the fecal-oral route, which can be attributed to the population density. Consequently, the pathogen triggers stress response and virulence factors deploying it to survive in hosts. Therefore, this study proposed to evaluate HPMCAS-coated microparticles containing the Ctx(Ile21)-Ha antimicrobial peptide against SE in laying hens chicks infection model to determine whether Ctx(Ile21)-Ha-utilization confers a benefit in the intestinal lumen, as well as whether limits systemic infection. Importantly, while assessing whether AMP utilization confers reduction of SE in liver, it was noted that there was statistical significance between groups A (control, no Ctx(Ile21)-Ha peptide) and B (2.5 mg of Ctx(Ile21)-Ha/kg) at 2 dpi, potentially indicating the Ctx(Ile21)-Ha effectiveness in the first stage of infection by SE. Remarkably, it was also detected a statistical significance (p -value <0.0001) with lower counts of SE ([~] 0 CFU) in livers at 5, 7, and 14 dpi, regardless of Ctx(Ile21)-Ha dosage (2.5 mg or 5 mg/kg - group C). By using Chi-square test, the AMP effect on SE fecal excretion was evaluated. In this regard, it was noticed statistical significance (p < 0.05) among groups B and C in comparison with control group A, since those groups had lower bacterial excretion along 21 days. In summary, the role of HPMCAS-Ctx(Ile21)-Ha peptide microcapsules against S. Enteritidis in laying hen chicks infection model was unraveled, providing a satisfactory results against this pathogen.

microbiology↗

bioRxiv2021

Alginate-based microparticles coated with HPMCP/AS cellulose-derivatives enable the Ctx(Ile21)-Ha antimicrobial peptide application as a feed additive

Microencapsulation is a potential biotechnological tool, which can overcome AMPs instabilities and reduce toxic side effects. Thus, this study evaluates the antibacterial activities of the Ctx(Ile21)-Ha antimicrobial peptide against MDR and non-resistant bacteria, develop and characterize peptide-loaded microparticles coated with HPMCAS and HPMCP. Ctx(Ile21)-Ha microencapsulation was performed by ionic gelation with high-efficiency, maintaining the physical-chemical stability. Ctx(Ile21)-Ha coated-microparticles were characterized, and their hemolytic activity assay demonstrated that hemolysis was decreased up to 95% compared to single molecule. In addition, in vitro release control profile simulating different portions of gastrointestinal tract was performed and showed the microcapsules ability to protect the peptide and release it in the intestine, aimed pathogens location, mainly by Salmonella sp. Therefore, use of microencapsulated Ctx(Ile21)-Ha can be allowed as an antimicrobial controller in monogastric animal production, being a valuable option for molecules with low therapeutic indexes or high hemolytic rates.

biochemistry↗