https://repositorio.ufu.br/handle/123456789/5167 Alterada nomencatura do antigo Instituto de Genética e Bioquímica: Resolução 05/99 do Conselho Universitário Fri, 18 Sep 2026 09:36:06 GMT 2026-09-18T09:36:06Z https://repositorio.ufu.br:443/retrieve/70b47b51-150e-460e-8b69-6e0d41786847/logo_ibec_vertical.png https://repositorio.ufu.br/handle/123456789/5167 https://repositorio.ufu.br/handle/123456789/50295 Title: Micrornas em alface (Lactuca sativa): novas descobertas sobre a regulação gênica pós-transcricional Abstract: MicroRNAs (miRNAs) are small non-coding RNAs involved in the post-transcriptional regulation of gene expression in plants, participating in processes related to development, metabolism, and responses to biotic and abiotic stresses. Despite the biological relevance of these regulators, there is still limited information regarding the components of the miRNA processing pathway in Lactuca sativa L., one of the most economically important leafy vegetables worldwide. Therefore, this study aimed to identify and characterize proteins involved in miRNA biogenesis, as well as to predict and analyze conserved miRNA families in L. sativa cv. Salinas and L. sativa var. angustana. The analyses were performed through genome mining, multiple sequence alignments, conserved domain prediction, thermodynamic analyses, and phylogenetic inference using orthologous sequences from plant species. Additionally, 193 mature miRNA sequences (3p and 5p) and 137 precursor miRNAs were identified, distributed among 36 distinct miRNA families. The precursors exhibited stable secondary structures and thermodynamic parameters compatible with true miRNAs. Overall, the results obtained expand the current knowledge regarding the miRNA processing pathway in lettuce and provide an important basis for future functional studies related to gene regulation, plant development, and biotechnological applications aimed at crop improvement. Tue, 02 Jun 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50295 2026-06-02T00:00:00Z https://repositorio.ufu.br/handle/123456789/50279 Title: Biossíntese e caracterização de nanopartículas de ouro a partir de extratos de flores e folhas de Calliandra dysantha: potencial antioxidante e antibiofilme Abstract: Nanotechnology is a research field that explores materials with nanometric dimensions, integrating knowledge from chemistry, physics, biology, and engineering to develop, manipulate, and apply these materials with unique properties. Among nanomaterials, gold nanoparticles are notable due to their physicochemical, optical, and biological properties. Green synthesis mediated by plant extracts represents a sustainable alternative to traditional physical and chemical methods, as it employs bioactive compounds capable of acting as reducing, stabilizing, and antimicrobial agents. Furthermore, antimicrobial resistance and bacterial biofilm formation represent significant public health challenges, as they hinder the efficacy of conventional treatments and promote infection persistence. Thus, this study aimed to perform, for the first time, the biosynthesis of gold nanoparticles using methanolic extracts from the flowers and leaves of Calliandra dysantha, a species native to the Brazilian Cerrado, as well as to characterize the resulting nanoparticles and evaluate their antioxidant and anti-biofilm potential against Staphylococcus aureus. Therefore, the present study aimed, for the first time, to biosynthesize gold nanoparticles using methanolic extracts of flowers and leaves of Calliandra dysantha, a species native to the Brazilian Cerrado, as well as to characterize these nanoparticles and evaluate their antioxidant and antibiofilm potential against Staphylococcus aureus. Gold nanoparticles were synthesized in aqueous medium using tetrachloroauric acid as the metal precursor under heating and stirring. Nanoparticle formation was confirmed by the presence of absorption bands at approximately 528 nm. Transmission electron microscopy analyses revealed the formation of spherical particles, with an average diameter of 13.8 ± 3.4 nm for gold nanoparticles synthesized with flower extract (F-AuNPs) and 20.8 ± 12.7 nm for those synthesized with leaf extract (L-AuNPs). The mean hydrodynamic diameters were 64.47 ± 10.62 nm for F-AuNPs and 80.55 ± 0.04 nm for L-AuNPs, with low polydispersity indices. Zeta potential values indicated moderate colloidal stability with low aggregation propensity of the dispersions. Assays performed using the DPPH and ABTS methods at concentrations ranging from 125 µg/mL to 15.625 µg/mL demonstrated high antioxidant activity in the plant extracts, suggesting the presence of antioxidant compounds that may contribute to the biosynthesis and stabilization of the nanoparticles. Antioxidant assays using the DPPH and ABTS methods at concentrations ranging from 125 µg/mL to 15.625 µg/mL demonstrated the high antioxidant activity of the plant extracts, suggesting the presence of antioxidant compounds that may contribute to the biosynthesis and stabilization of the nanoparticles. Conversely, the nanoparticles themselves exhibited low antioxidant activity, possibly due to decreased availability of bioactive compounds after synthesis. In the antibiofilm assay, all treatments showed higher activity at a concentration of 125 µg/mL. At this concentration, no significant differences were observed between treatments, indicating that both the extracts and the gold nanoparticles were able to significantly reduce the metabolic viability of Staphylococcus aureus biofilms. Thus, the results demonstrate that flower and leaf extracts of Calliandra dysantha have potential for the biosynthesis of gold nanoparticles with relevant physicochemical characteristics and antioxidant and antibiofilm activities, highlighting their potential for future biotechnological and biomedical applications. Wed, 26 Aug 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50279 2026-08-26T00:00:00Z https://repositorio.ufu.br/handle/123456789/50275 Title: Contribuições à Toxinologia de Formigas do Cerrado pela caracterização e bioprospecção de suas peçonhas e moléculas - uma abordagem experimental e in silico Abstract: Animal venoms are an established source of drugs, yet the field concentrates on snakes, scorpions and spiders, while ants, the richest lineage of venomous animals, remain underexplored, constrained by minute venom yields and by the gap between the abundance of omics data and the confirmed function of the molecules. The general aim of this thesis was to characterize and bioprospect the biotechnological and therapeutic potential of the venoms of Cerrado ants (and of their associated molecules and symbionts) through an integrated, experimental and in silico approach. Organized as a compilation of ten articles, it comprises three foundational reviews (methods in toxinology; the Brazilian contribution to ant toxinology; the ant microbiome), two systematic reviews on value and translation (the animal-toxin patent landscape; conservation as a bioeconomic strategy under the access-and-benefit-sharing regime), two experimental characterization studies, one computational study and two therapeutic-validation studies. Methods spanned biochemical, enzymatic and functional venom assays, mass spectrometry, a bioinformatics pipeline for sequence-based function prediction, and in vitro and in vivo assays of antimicrobial, immunomodulatory, antinociceptive and safety endpoints. Key results include the first toxinological characterizations of Neoponera foetida and Odontomachus haematodus, two Cerrado Ponerinae whose enzymatically rich venoms differ in function according to each species' ecology; an in silico pipeline that prioritized Hymenoptera peptides and highlighted ant dinoponeratoxins and ponericins as selective candidates; and the demonstration that the monomerized, non-lytic ectatomin subunits ET1A and ET1B are bactericidal against multidrug-resistant strains, restrain neutrophil extracellular trap formation without cytotoxicity, show antinociceptive potential in Drosophila melanogaster larvae, and are safe in the chick-embryo model. We conclude that Cerrado ant venoms are a promising source of bioactive molecules, that integrating experimental and computational approaches accelerates their discovery in neglected taxa, and that the resulting economic value may constitute an argument for biodiversity conservation. Fri, 21 Aug 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50275 2026-08-21T00:00:00Z https://repositorio.ufu.br/handle/123456789/50262 Title: Modelagem e docking molecular de Derlin-1: ligantes naturais e modulação do estresse do retículo endoplasmático em células de câncer de próstata Abstract: The endoplasmic reticulum (ER) plays a central role in protein synthesis, folding, and quality control. Its homeostasis is maintained by the Unfolded Protein Response and Endoplasmic Reticulum-Associated Degradation pathways, the latter being responsible for the retrotranslocation and degradation of misfolded proteins. Derlin-1 acts as a key component of the retrotranslocation channel in association with the p97/VCP ATPase, being activated by high protein demand. Accordingly, its overexpression has been described in different tumors, including prostate cancer (PCa), in which a strong dependence on proteostasis mechanisms is observed, especially in castration-resistant prostate cancer (CRPC). Indeed, in CRPC there is intense metabolic reprogramming and persistent activation of ER stress, such that Derlin-1 helps sustain transformed cells. In this scenario, the pharmacological modulation of Derlin-1 has proven to be a still poorly explored therapeutic strategy. Natural compounds are historically relevant, especially in oncology, and structural bioinformatics tools, such as homology modeling, docking, and molecular dynamics, combined with ADMET predictions, allow for the rational investigation of their interaction with ligands. Thus, this theoretical framework positions Derlin-1 as a relevant molecular target and explores the phenolic compound 4-nerolidylcatechol as a bioactive and structurally compatible natural candidate for modeling and molecular docking approaches aimed at CRPC. Mon, 31 Aug 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50262 2026-08-31T00:00:00Z