https://repositorio.ufu.br/handle/123456789/21238 Sun, 30 Aug 2026 13:49:32 GMT 2026-08-30T13:49:32Z https://repositorio.ufu.br/handle/123456789/49926 Title: Novos compostos da classe dos benzotiazóis: atividades biológicas e alterações moleculares em células tumorais mamárias triplo-negativas Abstract: Breast cancer is the most commonly diagnosed malignant tumor among women worldwide. Different therapeutic strategies are employed, and for its most aggressive subtype, triple-negative breast cancer (TNBC), chemotherapy remains the main clinical approach. However, the toxicity of the drugs used, the activation of resistance mechanisms, and recurrence rates remain major concerns. In this context, the search for new compounds is urgent, and benzothiazole-derived compounds have stood out due to their ability to modulate the redox and inflammatory status of cells. The present study aimed to evaluate the effects of nine novel compounds from this class in BC cell lines through cytotoxicity, clonogenicity, migration, and qPCR assays. Human non-tumoral cell lines HFF-1 (fibroblast) and MCF 10A (breast), as well as the tumor cell lines MCF7 (luminal BC) and MDA-MB-231 (triple-negative BC), were cultured. Among the tested compounds, only compound 2 showed activity and selectivity, with an IC50 = 12.26 µM and a selectivity index (SI) > 2.0. In addition, it significantly inhibited the clonogenicity and migration of triple-negative cells after 48 hours of treatment with 3.07 µM (IC50/4) and 6.13 µM (IC50/2) of 2. Finally, qPCR assays demonstrated that the compound 2 modulates the transcripts of IL6, TGFβ, KRT18, and VIM. Therefore, we suggest that compound 2 modulates the epithelial–mesenchymal transition process in TNBC cells, thereby controlling their aggressiveness. Additional studies are required to validate other EMT-related targets, including animal models. Wed, 29 Jul 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49926 2026-07-29T00:00:00Z https://repositorio.ufu.br/handle/123456789/49878 Title: Biossíntese de nanopartículas de ouro com extratos vegetais de Calliandra dysantha: estudo da atividade antibiofilme Abstract: Nanobiotechnology has advanced the sustainable biosynthesis of nanoparticles using plant derived bioactive compounds as reducing and stabilizing agents. Among these nanomaterials, gold nanoparticles have attracted considerable attention due to their unique physicochemical, optical, and biological properties. This study reports the biosynthesis of gold nanoparticles using flower and leaf extracts of Calliandra dysantha, a species native to the Brazilian Cerrado, and evaluates their antibiofilm activity against Staphylococcus aureus. The nanoparticles were synthesized using a green approach and characterized by ultraviolet-visible (UV-Vis) absorption spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis. Gold nanoparticle formation was confirmed by the characteristic localized surface plasmon resonance (LSPR) absorption band observed between 500 and 550 nm. Nanoparticles synthesized using flower extracts exhibited an average diameter of 13.8 ± 3.4 nm with low polydispersity, whereas those synthesized using leaf extracts showed an average diameter of 20.8 ± 12.7 nm and higher polydispersity. Dynamic light scattering analysis revealed that gold nanoparticles synthesized using flower extracts had a mean hydrodynamic diameter of 64.47 ± 10.62 nm and a polydispersity index (PDI) of 0.26 ± 0.01. In contrast, nanoparticles synthesized with leaf extracts exhibited a mean hydrodynamic diameter of 80.55 ± 0.04 nm and a PDI of 0.24 ± 0.02. Zeta potential measurements indicated moderate colloidal stability with a low tendency toward aggregation, with zeta potential values of −25 mV for flower extract-mediated nanoparticles and −23 mV for leaf extract-mediated nanoparticles. Antibiofilm activity was evaluated using the MTT assay, which enabled the assessment of the metabolic activity of biofilm-associated bacteria following exposure to the nanoparticles at concentrations of 125, 62.5, and 31.2 µg/mL. At 125 µg/mL, all treatments exhibited their greatest antibiofilm activity, indicating that both the extracts and the synthesized nanoparticles effectively reduced the metabolic activity of Staphylococcus aureus biofilms. Gold nanoparticles synthesized using flower extracts showed 93.51% antibiofilm activity, whereas those synthesized using leaf extracts showed 86% antibiofilm activity. These findings demonstrate that flower and leaf extracts of Calliandra dysantha serve as efficiently as reducing and stabilizing agents for the biosynthesis of gold nanoparticles with excellent antibiofilm activity, highlighting their potential for the development of novel strategies for bacterial biofilm control and future biotechnological applications. Thu, 06 Aug 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49878 2026-08-06T00:00:00Z https://repositorio.ufu.br/handle/123456789/49602 Title: Identificação e avaliação de atividade antimicrobiana de bactéria formadora de endósporo Abstract: Bioinputs stands out as a sustainable alternative to synthetic pesticides. In this scenario, spore-forming bacteria have relevance because they produce a diversity of antimicrobial bioactives that can be used in the biopesticides formulation. Therefore, the present work aims to identify and characterize a spore-forming bacterium isolated from Cerrado soil and evaluate its antimicrobial properties. The soil isolate was acquired from bacteria collection used in undergraduate courses at the Universidade Federal de Uberlândia on the Patos de Minas campus and cultivated in a non-selective medium. To identify the soil isolate, a polyphasic taxonomy was performed with tests of colony morphology, Gram microscopy, cellular morphology, growth curve (600 nm), antimicrobial characterization by cross-streak method, 16S rRNA Sanger sequencing and phylogenetic analysis using the SILVA and National Center for Biotechnology Information (NCBI) databases. Morphological results identified the soil isolate as a Gram-positive spore-forming bacterium with bacillus morphology and a growth curve lasting 12 hours. Identification by sequencing the 16S rRNA gene was reliable at the level of genus classification as Bacillus, revealing similarity of the soil isolate with the Bacillus cereus complex group of spore-forming bacteria, a clade of extreme difficulty regarding taxonomic characterization at the species level. Phylogenetic analysis corroborated the isolate classification to the group and the antimicrobial test presented a negative result against E. coli, Staphylococcus aureus, Pseudomonas sp., Staphylococcus epidermidis, Enterococcus sp. and Salmonella strains despite the range of antimicrobial compounds produced by the genus reported in the literature. The identification methods used were not sufficient for discrimination of the soil isolate at the species level, requiring a future multifaceted work for better identification. Mon, 27 Jul 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49602 2026-07-27T00:00:00Z https://repositorio.ufu.br/handle/123456789/49518 Title: Biossíntese de nanopartículas de prata utilizando extratos metanólicos de Calliandra dysantha: caracterização e avaliação da atividade antimicrobiana Abstract: The resistance of bacteria and fungi to conventional antimicrobial agents represents one of the major challenges in public health, driving the search for new therapeutic strategies. In this context, approaches based on nanotechnology and the use of bioactive molecules derived from Cerrado plants have contributed to the development of functional materials with biomedical potential. The green biosynthesis of silver nanoparticles (AgNPs) has emerged as a promising and sustainable alternative, as bioactive compounds present in plant extracts act simultaneously as reducing and stabilizing agents, minimizing the use of potentially toxic reagents. Therefore, this study aimed to synthesize AgNPs using methanolic extracts from leaves, flowers, stems, and roots of Calliandra dysantha, characterize the obtained nanoparticles, and evaluate their antimicrobial activity against Staphylococcus aureus, Escherichia coli, Talaromyces sp., and Rhodotorula mucilaginosa. The biosynthesis was performed in an aqueous medium using silver nitrate as a precursor under constant heating and stirring. The AgNPs were characterized by ultraviolet-visible absorption spectroscopy (UV-Vis), dynamic light scattering (DLS), and zeta potential analysis. Analyses of antioxidant potential were performed using the DPPH, ABTS, and ferric reducing power assays with the flower and leaf extracts. The antimicrobial activity was evaluated using the disk diffusion method. The formation of AgNPs was confirmed by the presence of a localized surface plasmon resonance (LSPR) band between 430 and 450 nm, with higher synthesis efficiency observed for flower and leaf extracts. DLS analyses revealed mean hydrodynamic diameters of 24.86 nm and 39.65 nm for AgNPs synthesized using flower and leaf extracts, respectively, with low polydispersity indices and zeta potential values of −23.3 mV and −24.0 mV, indicating moderate colloidal stability. In disk diffusion assays, no inhibition halos were observed for either AgNPs or plant extracts against the evaluated microorganisms, suggesting the need for optimization of synthesis conditions and sample concentrations, as well as the application of quantitative methods for antimicrobial activity assessment. It is concluded that C. dysantha has potential for the green synthesis of AgNPs with physicochemical characteristics consistent with those described in the literature, representing a promising source of biomolecules with antioxidant properties for the sustainable development of nanomaterials with possible applications in nanobiotechnology. Fri, 31 Jul 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49518 2026-07-31T00:00:00Z