http://repositorio.ufc.br/handle/riufc/58 2026-06-16T14:03:11Z http://repositorio.ufc.br/handle/riufc/86771 Título: Avaliação do teor inorgânico e bioacessível de arsênio em amostras de macroalgas do litoral do Ceará-Brasil Autor(es): Nobre, Iago Gabriel Medeiros Abstract: Brazil has an extensive coastline where a wide variety of macroalgae species can be found, especially in the northeast region. The global production of macroalgae has increased significantly in recent years due to its growing use in the cosmetics, pharmaceutical, and food industries. Macroalgae are capable of bioaccumulating inorganic elements, including potentially toxic ones such as arsenic (As). For this element, toxicity depends on its chemical form, with its inorganic species, As (III) and As (V), considered carcinogenic, while arsenobetaine is non-toxic. Consequently, speciation analysis of As in macroalgae, the study of the bioaccessibility of this element and physicochemical analyses are crucial to ensure the safety of consumers. In this study, the levels of As in four species of macroalgae from the Ceará coast (Sargassum vulgare, Ulva lactuca, Gracilaria birdiae, and Solieria filiformis) were determined by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) after sample digestion in an acidic medium with microwave-assisted heating. The macroalgae samples showed As contents ranging from 2.5 to 34.6 mg kg-1. The water-soluble species of As, including iAs, were extracted in water and analyzed by ICP-OES, representing 34-52% of the total As content. The iAs levels were measured by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) after magnetic solid-phase extraction and ranged from 0.15 to 2.59 mg kg-1. The species Sargassum vulgare stood out for having higher levels of As and iAs. Arsenic in a certified reference material sample ERM-CD200 (Bladderwrack - Fucus vesiculosus) was determined with statistically similar values at a 95% confidence level. The macroalgae samples showed high moisture content (67.9% to 86.7%), ash (13.43% to 34.44%), carbohydrates (62.09% to 79.98%), and proteins (3.47% to 6.59%), and low lipid content (<1%). The bioaccessibility analysis of As in the samples yielded results ranging from 0.98 to 11.54 mg kg, with percentages of bioaccessible arsenic relative to the total ranging from 33.31% to 58.13%. For a more conclusive assessment regarding the absorption of As by the body, in vivo bioavailability studies are necessary due to the involvement of more complex metabolic activities. Tipo: Dissertação 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86747 Título: Interação entre fungos endofíticos melanizados septados da caatinga e genótipos contrastantes de Vigna unguiculata [L.] Walp. sob déficit hídrico Autor(es): Tivane, Orpa Miguel Abstract: Drough is one of the main environmental stresses that limit agricultural productivity, especially in the semi-arid region of the northeast, where crops such as cowpea (Vigna unguiculata) have great socioeconomic importance. Melanized and septate endophytic fungi (DSEs) have been associated with plant growth promotion and the mitigation of water deficit effects, bult their functionality in agricultural crops is still poorly understood. This study avaluated the potential of DSE isolates native to the Caatinga to promove growth and contribute to water stress tolerance in contrasting genotypes of V. unguiculata, Pingo-de-Ouro ,2 (PO) and Santo Inácio (SI). Of the 14 isolated species, 14 colonized cowpea and 11 colonized corn. Among them, the DSE2 strain was selected for showing the best effects of water stress and maintaining plant growth. Inoculation with DSE2 resulted in a higher colonization rate under water stress, especially in the susceptible cultivar (SI). Additionally, it promoted an increase in intrinsic water use efficiency, with a more pronounced effect in the tolerant cultivar (PO). The water regime was the main determining fator for changes in the leaf and root metabolome, while inoculation with DSE2 exerted a secundary modulatory effect. However, in the root system of the SI cultivar, the presence of DSE2 promoted more expressive metabolic reprogramming associated with the response to water stress. The results show that native DSEs from the Caatinga have the potential to modulate physiological and metabolic responses of V.unguiculata under water deficit, with effects depending on the water regime, genotype, and organ analyzed. Tipo: Dissertação 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86711 Título: Estudo racional de triterpenos do tipo lanostano como potenciais inibidores da proteína MYC: avaliação in silico Autor(es): Oliveira, José Augusto Carneiro de Abstract: The MYC protein is one of the most investigated molecular targets for anticancer therapy. The structural characteristics of this intrinsically disordered protein have made inhibitor development a challenge. Lanostane-type triterpenes, such as pisosterol, are secondary metabolites constantly investigated for their anticancer activities. In this study, the anti-MYC potential of 821 lanostane-type triterpenes was investigated using ensemble docking, structural property prediction, pharmacokinetic parameters, molecular dynamics, and free energy calculation using the MM-GBSA method. As a result, the ligands (I-VIII) known as ganoderic acid E (I), ganoderlactone D (II), ganoderic acid Y (III), ganoderic acid Df (IV), lucidenic acid F (V), ganoderic acid XL4 (VI), mariessiic acid A (VII), and phellinol E (VIII) exhibited properties within the filters used. These eight ligands interacted with the molecular target, presenting interaction energies between -8.3 and -8.6 kcal.mol-1. In molecular dynamics, the RMSD, RMSF, radius of gyration, and hydrogen bonding plots revealed that ligands I, IV, VI, and VII interacted satisfactorily with the protein during the simulations, contributing to its conformational and energetic stabilization. The MYC-I and MYC-VII complexes presented free energies of -41.96 kcal.mol-1 and -44.98 kcal.mol-1, respectively. These results demonstrate that lanostane-type triterpenes were able to interact with MYC, forming stable complexes, suggesting that these molecules have the potential to inhibit the target Tipo: Tese 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86611 Título: Potencial dendrocronológico e relações clima-crescimento em espécies de manguezal Autor(es): Silva, Mateus de Oliveira Tipo: Dissertação 2026-01-01T00:00:00Z