DSpace Community: Alterada nomencatura do antigo Instituto de Genética e Bioquímica: Resolução 05/99 do Conselho Universitário

Aplicações translacionais de Drosophila melanogaster em neurociência: mecanismos moleculares, modelos de doenças e investigação terapêutica

2026-05-19T06:34:47Z

Title: Aplicações translacionais de Drosophila melanogaster em neurociência: mecanismos moleculares, modelos de doenças e investigação terapêutica Abstract: This thesis investigated the translational applications of Drosophila melanogaster in neuroscience through studies focused on neurodegeneration and nociception. In the first study, metabolic and peptide fractions derived from kefir were evaluated in amyloidogenic models of Alzheimer’s disease in D. melanogaster and in cell culture. The biomolecules were investigated using biochemical, in vitro, and in vivo approaches. The results demonstrated the neuroprotective potential of the kefir-derived fractions, including attenuation of neurodegenerative phenotypes, improvement of oxidative parameters, and reduction of neurodegeneration-associated alterations in the experimental models. In the second study, a voltage-gated sodium channel mutant model in D. melanogaster was validated as an experimental tool for investigating mechanisms related to nociception and chronic pain. Using this model, the modulatory potential of cannabidiol (CBD) on nociceptive parameters and conserved neural pathways associated with pain signaling was evaluated. Collectively, the findings reinforce the translational relevance of D. melanogaster as a model organism in neuroscience, highlighting its applicability in the investigation of conserved molecular mechanisms, the experimental modeling of neurological diseases, and the prospecting of therapeutic strategies with neuroprotective and analgesic potential.

Produtos Naturais como Fontes de Compostos Biotecnológicos e Terapêuticos

2026-05-06T06:25:53Z

Title: Produtos Naturais como Fontes de Compostos Biotecnológicos e Terapêuticos Abstract: This thesis investigated natural products as sources of biotechnological and therapeutic innovation in two studies. In the first study, the total water-soluble fraction of kefir (WSF) and its <10 kDa fraction were used for the green synthesis of silver nanoparticles (AgNPs). The WSF-AgNPs exhibited an absorbance peak at 470 nm, a negative zeta potential (-30 mV), and a broad hydrodynamic size distribution (500-1000 nm). AgNPs derived from the <10 kDa fraction showed predominantly smaller particles (50-200 nm), although with lower stability. The WSF-AgNPs inhibited multidrug-resistant bacteria, with MIC values of 25 μg/mL for Acinetobacter baumannii and 50 μg/mL for Klebsiella pneumoniae, showing bactericidal activity at the minimum inhibitory concentrations. In Drosophila melanogaster, larval exposure to 100 μg/mL impaired developmental parameters, whereas no robust changes in 15-day adult survival were observed, despite subtle signs of redox imbalance, suggesting a dose- and stage-dependent safety window. In the second study, ethanolic and acetonic extracts of Saskatoon berry (Amelanchier alnifolia) were characterized by LC-MS/MS and in silico analyses, indicating solvent-dependent composition and potential interactions with targets associated with Alzheimer’s disease. The acetonic extract showed higher total phenolic content and strong antioxidant performance. In cellular models, it exhibited low cytotoxicity and a neuroprotective effect under beta-amyloid peptide challenge. In D. melanogaster, supplementation with both extracts increased longevity in healthy flies and, in the AD-like model driven by GMR-GAL4, the acetonic extract reduced beta-amyloid burden and preserved retinal thickness and structure, with a tendency toward dose- and sex-dependent responses. Together, these findings support the potential of fermented matrices and polyphenol-rich fruits as promising sources of candidates for antimicrobial and neuroprotective applications.

Biorremediação utilizando microrganismos, como alternativa para o tratamento de efluentes contaminados com corantes: uma revisão.

2026-03-24T06:26:51Z

Title: Biorremediação utilizando microrganismos, como alternativa para o tratamento de efluentes contaminados com corantes: uma revisão. Abstract: The textile industry occupies a prominent position in the global economy. However, the fabric finishing process results in the generation of large volumes of effluents loaded with synthetic dyes, compromising the quality of water resources and aquatic life. This work aims to analyze the efficiency of bioremediation using microorganisms as a sustainable technological strategy for the degradation of these recalcitrant compounds. The methodology is based on an integrative literature review conducted in the Science Direct and Scielo databases, as well as in institutional repositories, prioritizing studies that address the application of microorganisms, focusing on fungi, and their enzymatic systems in wastewater. The results indicate that the use of bacteria and fungi, especially white-rot fungi, promotes the breakdown of the chemical structure of dyes through the action of oxidoreductase enzymes, such as laccases and peroxidases, among others, such as hydrolases, lipases, and proteases. It is identified that the stability of these biological agents is directly influenced by environmental and physicochemical variables. It is concluded that the decontamination of textile effluents containing synthetic dyes constitutes a huge challenge for the industry, especially the Textile Industry, with bioremediation promoted by microorganisms, particularly fungi that produce oxidoreductase enzymes, representing a viable alternative capable of ensuring greater sustainability throughout the production chain. The implementation of enzymatic immobilization techniques and the use of microbial consortia will additionally bring necessary advances to ensure operational robustness and enable the practical application of this system in environmental decontamination.

Avaliação in vitro do efeito dos pesticidas dimetomorfe e fenpropimorfe em células hepáticas humanas

2026-03-21T06:26:19Z

Title: Avaliação in vitro do efeito dos pesticidas dimetomorfe e fenpropimorfe em células hepáticas humanas Abstract: Brazil is one of the largest consumers of pesticides worldwide, and some of these compounds have had their use restricted by international regulatory agences due to the lack of knowledge regarding their impacts on human health. Among the most widely used classes, fungicides receive considerable attention given their high toxicological potential. Therefore, the present study aims to evaluate, in silico and in vitro, the effects of the morpholine fungicides dimethomorph (DIM) and fenpropimorph (FEN) on two human hepatic cell lines. The ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) predictions indicated a high hepatotoxic potential and a tendency toward bioaccumulation for both compounds. Cell viability was assessed using Sulforhodamine B assay after incubation of the cells at concentrations of 300, 150, 75, 37.5, 18.75, and 9.375 µg/mL for DIM and 2, 1, 0.5, 0.25, 0.125, and 0.0625 µg/mL for FEN over a 24-hour period. For the LX-2 cell line, only the concentrations of 300 µg/mL (DIM) and 1 µg/mL (FEN) showed a significant decrease in viability. In HepG2 cells, treatments below 75 µg/mL (DIM) and above 0.25 µg/mL (FEN) resulted in reduced viability and increased production of reactive oxygen species (ROS), highlighting the possible role of such molecules in hepatotoxicity mechanisms and cell death. Additional studies are required to elucidate the molecular mechanisms involved.