http://repositorio.ufc.br/handle/riufc/82 2026-05-13T19:42:12Z http://repositorio.ufc.br/handle/riufc/86254 Título: Filmes à base de polissacarídeos sulfatados da alga marinha vermelha (hypnea pseudomusciformis) incorporados com óleo de babaçu: elaboração e caracterização Autor(es): Lima, Erivan Santos Abstract: The production of biodegradable packaging has increased, along with the interest of researchers and industries, aiming to reduce the impact caused by the use and disposal of packaging made from synthetic materials derived from fossil hydrocarbons. This study aimed to develop and characterize biodegradable films based on sulfated polysaccharide (SP) extracted from the red alga Hypnea pseudomusciformis, incorporated with babassu oil at different concentrations. Polysaccharide extraction was carried out using two methods (aqueous extraction - AE and refined aqueous extraction - RAE), with yields of 31.50% and 10.35%, respectively. Six treatments were prepared, varying the concentration of carrageenan (5%, 10%, 15%) and babassu oil (1%, 3%, 6%), using glycerol as a plasticizer. The films were evaluated for physical (thickness, moisture), optical (color, transparency), barrier (water solubility), thermal (DSC, TGA), chemical (FTIR) properties, and soil biodegradability. Statistical analysis included descriptive statistics, multivariate analysis, and the use of R software. The results showed that oil incorporation improved handling and visual homogeneity, especially in treatments with 5% polysaccharide + 1% oil (T4) and 15% polysaccharide + 6% oil (T6). FTIR analysis confirmed the carrageenan structure in the films and the presence of babassu oil through the band at ~1740 cm⁻¹. Biodegradability was high (>70% after 10 days), and the addition of oil increased the thermal stability of the films, with T6 showing the highest resistance (lowest mass loss). It is concluded that the combination of SP and babassu oil is viable for the production of biodegradable films, allowing their properties (such as transparency, moisture resistance, and degradation rate) to be adjusted through formulation, demonstrating their potential for specific applications in sustainable packaging. Tipo: Dissertação 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85495 Título: Caracterização da pesca e da comercialização de Cyanocyclas brasiliana (Deshayes, 1854) (Mollusca: Bivalvia), no Delta do Parnaiba - PI Autor(es): Xavier, Athos Campêlo Ferreira Abstract: The species Cyanocyclas brasiliana is a bivalve mollusk of great economic and social importance for artisanal fishing on the coast of Piauí. For this reason, it has been the subject of recent studies seeking to understand its production chain, as well as its morphological and physicochemical characteristics. The extraction of this resource is based on shellfish gathering, a traditional harvesting practice passed down from generation to generation, especially among local families in the Parnaíba Delta. Carried out predominantly by women during low tide, this activity has significant socioeconomic relevance, ensuring family subsistence through the capture, processing, and commercialization of the shellfish. The present study aimed to characterize the fishing and commercialization of C. brasiliana in the Delta region, specifically in the municipality of Ilha Grande. To this end, the research was conducted through the observation of fishing practices and interviews with community members, aiming to obtain a comprehensive understanding of the entire dynamics of the production chain. The fishing of the bivalve mollusk Cyanocyclas brasiliana in the Parnaíba Delta is characterized by the use of selective, low-impact artisanal techniques, strongly guided by traditional ecological knowledge. However, processing and post-capture management lack infrastructure and sanitary control, limiting food security and access to more demanding markets. The commercialization chain is short, informal, and dominated by middlemen, which reduces the negotiating power of the shellfish gatherers and the value added to the product. It is concluded that the socio-environmental and economic sustainability of the activity depends on the articulation between public policies, structural improvements in post-capture, and the strengthening of community social organization (such as cooperatives), aiming to ensure the autonomy of producers and the efficient management of resources. Tipo: Dissertação 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85490 Título: Primeiro relato de uma lectina relacionada ao fibrinogênio em esponjas marinhas: caracterização bioquímica, estrutural e avaliação do potencial antibiofilme da lectina de Aplysina cauliformis (Carter, 1822) Autor(es): Oton, Levi Ferreira Abstract: Marine sponges are sessile invertebrates recognized for producing a vast chemical arsenal with biotechnological properties, with lectins standing out for their antimicrobial, anticancer, and immunomodulatory activities. Recently, studies with the lectin AcL (Aplysina cauliformis) revealed synergistic effects with antibiotics, highlighting the need for an in-depth biochemical and structural characterization, as well as an evaluation of its potential against bacterial biofilms. The present study aimed to isolate, purify, and biochemically and functionally characterize AcL, determining its primary and tertiary structures, as well as its interaction thermodynamic parameters and antibiofilm potential.The results revealed that AcL presents a molecular mass of approximately 35 kDa under reducing conditions and 66 kDa under nonreducing conditions, suggesting a dimeric organization stabilized by disulfide bonds. DLS analyses confirmed that the protein is predominantly in a stable dimeric state in solution, with a hydrodynamic diameter between 7 and 8 nm. Amino acid sequencing identified 13 peptides (40% coverage of the genomic sequence), revealing that AcL has 320 residues and is characterized as the first report of a marine sponge lectin containing a fibrinogen-related domain (FReD). Three-dimensional modeling demonstrated an unprecedented architecture for poriferans, composed of an N-terminal fibrillar domain (long alpha-helix) and a C-terminal beta-sandwich domain. In ITC assays, AcL demonstrated high affinity for the PSM glycoprotein (KD = 134 nM), with the interaction being driven mostly by entropic effects. Regarding antibiofilm activity, AcL strongly inhibited biomass formation in all tested strains, with reductions exceeding 80% for S. aureus at concentrations starting from 125 μg/mL, in addition to significant inhibition (over 50%) for S. epidermidis and a dose-dependent effect against E. coli. Although there was no drastic reduction in the count of viable cells at most concentrations, the effectiveness in destabilizing the biofilm biomass was compelling. It is concluded that AcL inaugurates a new class of lectins in the phylum Porifera, positioning itself as a promising molecule for the development of anti-virulence strategies and marine biotechnology. Tipo: Dissertação 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85070 Título: Purificação, caracterização bioquímica e estrutural de duas novas lectinas da esponja marinha Aplysina Pseudolacunosa (Pinheiro; Hajdu, 2007) Autor(es): Silva, João Marcelo de Sousa Abstract: Marine sponges, belonging to the phylum Porifera, are important sources of bioactive biomolecules, including lectins, which are proteins capable of recognizing and reversibly binding to specific carbohydrates. The species Aplysina pseudolacunosa, found along the coast of Ceará, had not yet had any lectins characterized in the literature. Therefore, this study aimed to purify and biochemically and structurally characterize two lectins from this species, named ApL-1 and ApL-2. The lectins were purified by ammonium sulfate precipitation, followed by affinity chromatography and reverse-phase high-performance liquid chromatography. In SDS- PAGE, ApL-1 exhibited an apparent molecular mass of approximately 12 kDa, whereas ApL-2 showed a mass of about 28 kDa. Both lectins displayed hemagglutinating activity, with titers of 32 U.H. mL−1 for ApL-1 and 128 U.H. mL−1 for ApL-2. ApL-1 showed greater affinity to bovine fetuin, while ApL-2 was strongly inhibited by porcine gastric mucins types II and III. Both lectins maintained activity over a wide pH range (4–10), exhibited thermal stability and divalent ion–independent activity. Circular dichroism characterization revealed distinct conformational architectures, with a predominance of β-sheet structures for ApL-1, consistent with galectins described from marine sponges, whereas ApL-2 exhibited a structural organization with a higher content of α-helical structures. Dynamic light scattering analyses indicated a monodisperse behavior for ApL-1, suggesting a dimeric organization in solution, and a more heterogeneous profile for ApL-2, indicating a higher degree of molecular association. The primary structure of ApL-1 was fully elucidated by tandem mass spectrometry (MS/MS). BLASTp analyses revealed high homology with galectins from marine sponges, particularly the isoforms ALL-a and ALL-b, with sequence identities of 86.9% and 78.6%, respectively, and 100% sequence coverage, compatible with the structural pattern described for proto-galectins. ApL-2 had its primary structure partially characterized, and alignments with putative proteins from marine sponge genomes showed identities ranging from 34 to 41% with low sequence coverage, suggesting that it represents a non-conventional lectin. Thus, the two new lectins characterized in this study expand the current knowledge of structural and functional diversity among marine sponge lectins and provide a foundation for future biological characterization and potential biotechnological investigation, pending further functional validation. Tipo: Dissertação 2026-01-01T00:00:00Z