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Atividades biológicas de extratos e frações da macroalga marinha vermelha Hypnea pseudomusciformis (Nauer, Cassano & Oliveira)

2026-08-04T12:05:21Z

Título: Atividades biológicas de extratos e frações da macroalga marinha vermelha Hypnea pseudomusciformis (Nauer, Cassano & Oliveira) Autor(es): Rebouças, Beatriz Emilly Alves Abstract: This study aimed to investigate the biotechnological potential of the red marine macroalga Hypnea pseudomusciformis, collected from Pacheco Beach, Caucaia, Ceará, Brazil. Extracts and fractions were analyzed to evaluate their biological activities, toxicity, and application in edible films. The algal biomass was subjected to sequential extraction using solvents of increasing polarity (hexane, ethyl acetate, and methanol), in addition to the extraction of sulfated polysaccharides. Subsequently, the extracts were fractionated by liquid-liquid partitioning and analyzed by thin-layer chromatography, leading to the preliminary characterization of the present secondary metabolites. The contents of total phenolic compounds and flavonoids were quantified, and the antioxidant activities were evaluated by the DPPH and ABTS+ free radical scavenging methods, ferrous ion chelating power (FIC), ferric ion reducing power (FRAP), and -carotene bleaching inhibition. The obtained fractions were also subjected to toxicological assays against seeds of improved Aodai cucumber (Cucumis sativus), Artemia sp. nauplii, and zebrafish (Danio rerio), evaluating possible phytotoxic and/or cytotoxic effects. Additionally, the incorporation of the fractions into carrageenan-based edible films was investigated, evaluating physicochemical properties such as water vapor permeability, thickness, solubility, and colorimetric parameters. The results demonstrated that the extracts and fractions contained different chemical profiles and biological activities, highlighting the influence of solvent polarity on the extraction of bioactive compounds. The variable antioxidant capacity of algal extracts, across different assays, showed their potential for application as a natural source of antioxidants. In toxicological tests, the response depended on the concentration, with greater toxicity at higher concentrations, especially for the hexane fraction. The edible films incorporated with the fractions showed alterations in physical and colorimetric properties, demonstrating potential for application in biodegradable packaging systems with functional potential. Thus, the results obtained show that H. pseudomusciformis constitutes a promising source of bioactive compounds with potential application in the pharmaceutical, food, and biotechnological fields. Tipo: Dissertação

Estudos estruturais e de expressão heteróloga de lectinas de organismos marinhos com potencial biotecnológico

2026-07-22T17:51:34Z

Título: Estudos estruturais e de expressão heteróloga de lectinas de organismos marinhos com potencial biotecnológico Autor(es): Sousa, Andressa Rocha de Oliveira Abstract: Marine organisms possess bioactive compounds with numerous described biological activities. Among these compounds are lectins, proteins or glycoproteins that exhibit specific and reversible binding to carbohydrates. Structural studies of lectins and their protein-carbohydrate interactions are important, as the glycosylation pattern of the cell surface is the key to understanding the functions of these molecules, providing mechanisms for biotechnological applications. However, information on the structure and specificity of these molecules from marine organisms is still scarce. In this sense, strategies focused on the production of recombinant proteins are important tools for structural studies and for the large-scale production of proteins with a biotechnological focus. This study aimed to produce, in a heterologous system, the marine algae lectin AmL (Amansia multifida lectin) and the marine invertebrate egg lectins ELEL (Echinometra lucunter eggs lectin) and ADEL (Aplysia dactylomela eggs lectin), to characterize them biochemically and structurally, and to evaluate the antibacterial potential of the former in combination with antibiotics. Furthermore, the study aimed to determine the three-dimensional structures of galectins derived from marine sponges, CCL (Chondrilla caribensis lectin) and ALL (Aplysina lactuca lectin), and to evaluate the interaction of these proteins with their respective ligands. The lectin rELEL was not expressed with solubility and functionality, despite attempts in different vectors, numerous expression conditions, and refolding and cotransformation strategies. The recombinant lectin rADEL was expressed in a heterologous system of Komagataella pastoris, which was biologically active, but with unsatisfactory yield. The lectin rAmL was expressed in a heterologous system of Escherichia coli, is biologically active, and biochemically similar to the native protein. rAmL showed antibacterial activity associated with the antibiotic tetracycline against Staphylococcus aureus and E. coli. The both galectins, ALL and CCL, had their three-dimensional structure determined by X-ray crystallography, and the lectin-carbohydrate interaction analyzed by cocrystallization and isothermal titration calorimetry. Therefore, these results significantly expand the structural knowledge about lectins from marine organisms, providing new ideas for the functional understanding of lectins from these organisms, whose structural studies are still scarce. Tipo: Tese

Efeitos da aplicação de óleos essenciais à dieta de tilápia-do-nilo (Oreochromis niloticus)

2026-06-17T17:45:16Z

Título: Efeitos da aplicação de óleos essenciais à dieta de tilápia-do-nilo (Oreochromis niloticus) Autor(es): Cunha, Angélica de Oliveira Portela Abstract: Global population growth poses challenges to sustainable food production, highlighting aquaculture as a strategic alternative for supplying animal protein. In this context, Nile tilapia (Oreochromis niloticus) stands out due to its high adaptability to intensive farming systems, rapid growth, and wide commercial acceptance. However, the intensification of production favors the emergence of diseases and the excessive use of antibiotics, driving the search for natural additives capable of improving fish performance and health. Thus, essential oils emerge as promising additives due to their antimicrobial, antioxidant, and immunomodulatory properties. The present study evaluated the palatability and the zootechnical and histological effects of dietary supplementation with different essential oils for juvenile Nile tilapia under controlled laboratory conditions. The essential oils of Cassia Cinnamon (Cinnamomum cassia), Lemongrass (Cymbopogon flexuosus), Eucalyptus (Eucalyptus staigeriana), and Oregano (Origanum vulgare) were individually supplemented at concentrations of 0.1, 1, and 10 mL/kg of commercial feed. Zootechnical performance was evaluated through Mean Weight, Total Weight Gain (TWG), Apparent Feed Conversion Ratio (FCR), and Survival, while palatability was assessed through feed intake tests and latency to the first feeding attack. The results demonstrated a positive effect of supplementation at intermediate concentrations (1 mL/kg), reinforcing the existence of an optimal inclusion range. Cassia Cinnamon and Lemongrass showed the greatest growth increments, with estimated additional gains of approximately 1.3 g and 1.2 g compared to the control group, respectively. Cassia Cinnamon presented the best overall productive performance, with greater zootechnical stability and absence of relevant histological alterations, whereas Lemongrass promoted growth enhancement associated with mild gastric alterations compatible with adaptation to dietary stimulus. Oregano stood out for its functional effects on palatability and feeding behavior, while Eucalyptus showed more discrete effects, mainly related to the initial acceptance of the diets. Overall, the essential oils proved to be biologically safe, maintaining high survival rates (92.5–100%) with no adverse effects on water quality or tissue integrity. It is concluded that the evaluated essential oils present potential as functional and attractant-palatability additives in Nile tilapia farming, especially at intermediate concentrations, highlighting Cassia Cinnamon as a promoter of productive performance, Lemongrass for its growth-stimulating potential associated with adaptive responses of the digestive tract, and Oregano as a modulator of feeding behavior and physiological responses in fish. Tipo: Dissertação

Substituição total e parcial da ração comercial por farelo de soja fermentado durante a fase de berçário intensivo do camarão Litopenaeus vannamei

2026-05-26T14:36:20Z

Título: Substituição total e parcial da ração comercial por farelo de soja fermentado durante a fase de berçário intensivo do camarão Litopenaeus vannamei Autor(es): Gomes, Igor Gabriel Rodrigues Ferreira Abstract: The shrimp farming industry has been experiencing a movement towards intensification, which allows an increase in productivity with a better use and of natural resources. The growth of this sector is associated with the availability of quality post-larvae and juveniles. The use of intensive nursery is an important strategy for biphasic systems, providing better results during the grow-out phase, increasing survival and growth of farmed animals. Despite this, its use requires qualified labor and feeds with high levels of crude protein, which represent greater cost and a potential risk to the water quality, thus, to the health of the animals. Thus, it is necessary to develop strategies that allow the improvement of this culture system. This study aimed to evaluate the effect of replacing commercial feed with fermented soybean meal, using a commercial probiotic, composed of a mix of organisms, during the intensive nursery phase of L. vannamei carried out under commercial conditions. Thus, five replacement percentages were evaluated, as 0%, 25%, 50%, 75% and 100%. Zootechnical parameters, water quality, zooplankton density and standard plate count for bacteria of the genus Vibrio spp. in the nursery water were evaluated. It was possible to replace the commercial diet with 100% fermented soybean meal without affecting the final survival, specific growth rate (%) and feed conversion. It was possible to replace the feed up to 50%, without negative effect on average final weight (g) and daily weight gain (g/day). The final average productivity (kg/m³) and yeld (kg/m³) were affected only when the replacement level exceeded 75%. It was possible to replace up to 100% without prejudice to water quality parameters such as pH, dissolved oxygen (mg/L), total ammonia (mg/L), nitrite (mg/L) and alkalinity (mg/L of CaCO3). The total zooplankton density was higher in the SJ25% treatment, when compared to the others, which did not differ (p>0.05). The standard plate count of Vibrio spp. was not influenced by the different replacement levels, the exception being the SJ50% treatment, which reached the highest value (p<0,05). The results indicate that the use of fermented soybean meal can be used as food for L. Vannamei‘s post-larvae in intensive nursery. A maximum replacement rate of 50% is suggested, in order to maintain the pattern of development observed with the use of a protocol with commercial rations. Tipo: Tese