Navegando por Autor "Bezerra, Raquel Pedrosa"

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Atividade larvicida do extrato celular e de lectina extraídos de Chlorella vulgaris frente larvas em L4 de Aedes aegypti
(2020-11-11) Silva, Maria Laura da; Bezerra, Raquel Pedrosa; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/0330489267196523
Dengue, chikungunya and zika are viral diseases caused by the transmitting agent Aedes aegypti. According to data from the World Health Organization (WHO), the numbers of cases of these infections are increasing, the main method of prevention being the use of chemical insecticides to combat the vector, which has provoked resistance in the populations. The search for insecticides extracted from natural sources has been an alternative, thus, microalgae appear as a new possibility because they present biodegradable and non-toxic bioactives. Therefore, this research aimed to use the cell extract and Chlorella vulgaris lectin on A. aegypti to investigate larvicidal activity and inhibition on trypsin in the fourth larval stage (L4). The biomass of C. vulgaris was grown in Bold's Basal Medium. The biomass was concentrated and resuspended in a proportion of 10% w / v in 0.1 M Tris-HCl-NaCl buffer, pH 7.5 for the preparation of the cell extract by magnetic stirring for 9h and later performed hemagglutinating activity. Lectin was purified using anionic chromatography (DEAE-Sephadex) and Superdex 75 molecular exclusion. Cell extract at concentrations of 3.13% to 100%, and lectin from 25 to 200 μg mL-1, were applied to the larvae A. aegypti L4 during the 72-hour period following WHO recommendations. The cell extract showed an LC50 value with 3 hours (LC50 = 43.50%) and 24 hours (LC50 = 10.62%). While lectin showed LC50 at 24 hours (164.2 μg mL-¹), 48 hours (125.3 μg mL-¹) and 72 hours (106.5 μg mL-1). To observe the mechanism of action of intestinal trypsin, the LC50 of the cell extract containing 260 μg ml-1 of protein was applied to the fourth stage of A. aegypti larvae. Upon reaching the fourth stage, the larvae were incubated with the microalgae cell extract for a total period of 10 hours, and every 2 hours trypsin activity was performed. It was observed that the longer the cell extract treatment time with the larvae, the greater the reduction in intestinal extract trypsin activity. There was a 34.93% reduction in activity from the initial time with 2 hours to the final time with 10 hours. Thus, the present study using the cell extract, as well as the lectin isolated from C. vulgaris, appears as a new larvicidal potential of A. aegypti.
Caracterização e avaliação do potencial de geliﬁcação dos polissacarídeos extraídos da Arthrospira (Spirulina) platensis
(2025-03-10) Silva, Sara Cadete da; Bezerra, Raquel Pedrosa; Silva, Marllyn Marques da; http://lattes.cnpq.br/5819032802869221; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/5393058542194680
Arthrospira platensis, conhecida como Spirulina é uma cianobactéria filamentosa amplamente distribuída em diversos ambientes e valorizada por seu alto teor nutricional e metabólitos bioativos. Composta majoritariamente metabólitos bioativos, como proteínas, carboidratos, lipídeos e minerais, que podem ser influenciados por fatores ambientais. Os polissacarídeos se destacam por suas propriedades funcionais e bioativas, incluindo efeitos imunomoduladores, antioxidantes e antivirais. Embora pouco estudados em comparação com os de macroalgas, além de apresentarem potencial gelificante, sugerindo aplicações em encapsulação. Portanto, o objetivo deste trabalho é caracterizar bioquimicamente e avaliar o potencial gelificante dos polissacarídeos extraídos da Arthrospira platensis. O microrganismo Arthrospira platensis foi cultivada em meio de cultura Schlösser modificado, com adição de 0,2% de milhocina, em agitação e iluminação constantes. Ao final do cultivo a biomassa produzida foi concentrada e ressuspendida em etanol absoluto (1:8), aquecida a 70 °C por 4 horas para a extração dos polissacarídeos. Os polissacarídeos foram ressuspendidos em solução de Savage para remoção de proteínas e lipídios residuais e utilizados para determinação de carboidratos totais, carboidratos redutores, carboidratos não redutores, teor de sulfatação e gelificação em soluções de cátions monovalente (NaCl), bivalente (CaCl₂) e trivalente (FeCl₃) a 100 mM e pH 6. A extração de polissacarídeos de Arthrospira platensis com etanol como precipitante obteve um rendimento de 31%. Na concentração de 10 mg/mL, as dosagens de carboidratos totais, redutores, não redutores e teor de conteúdo sulfatado foram de 0,89 mg/mL, 0,28 mg/mL, 0,6 mg/mL e 1,4 mg/mL respectivamente. Testes de gelificação com cátions monovalente (NaCl), bivalente (CaCl₂) e trivalente (FeCl₃) a 100 mM e pH 6 não resultaram em formação de geis, embora a solução de polissacarídeo concentrado a 1% tenha mostrado resistência à diluição na presença de CaCl₂. A Arthrospira platensis apresentou bom rendimento na extração de polissacarídeos e alto teor de conteúdo sulfatado. Apesar de não terem formado geis com cátions, mostrou-se resistência à diluição com CaCl₂, indicando potencial funcional e necessidade de estudos adicionais para otimizar suas propriedades gelificantes.
Descoloração do corante têxtil marinho Direct 2R utilizando o fungo Aspergillus tamarii kita UCP 1279
(2021-12-03) Cruz, Nayara Vitória dos Santos; Bezerra, Raquel Pedrosa; Silva, Raphael Luiz Andrade; http://lattes.cnpq.br/4770766127962026; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/9306095300572849
Synthetic dyes are widely used in textile industries, being characterized as easy- to-use substances, with great variety and profitability. Despite their attractiveness, dyes are also considered complex compounds, being characterized by their toxicity, hazardousness and difficult degradation. Treating wastewater before release into water bodies is essential for the environment. The biological method can be used with algae, bacteria, and fungi, the latter organisms being considered as one of the best models for treating effluents. Therefore, the present study sought to investigate the use of the fungus Aspergillus tamarii kita UCP 1279, isolated from the Caatinga Biome, to discolor a solution containing a textile dye from a laundry located in the interior of the state of Pernambuco. The discoloration of the Marine Direct 2R dye was evaluated at a concentration of 50 mg/L, these experiments were carried out using the microorganism A. tamarii kita under living and dead conditions, in different amounts of biomass (2, 4, and 6 grams). In addition, biomass reuse was evaluated, so that, after the first decolorization test of 120 minutes, two further decolorization sequences with 120 minutes each were conducted for all conditions. The best condition obtained with 2 grams of biomass was found in the dead condition, which, in just 15 minutes, discolored 97% of the color while, with 4 and 6 grams of biomass, the best performance was verified in the living condition, in which, at 15 minutes it reached 100% removals for both 4 and 6 grams of biomass. In the tests with the reuse of biomass, both conditions (live/dead) demonstrated efficiency in discoloring the dye in different quantities of biomass, at the end of the tests, thus showing the potential of the microorganism A. tamarii kita in carrying out the dye decolorization textile. Therefore, due to the effectiveness of the microorganism, the development of future research investigating the optimization of the process deserves to be studied, to provide an understanding of the best conditions for using A. tamarii kita, so that its use can be made viable on an industrial scale, as a new biological method to treat effluents containing textile dyes.
Desenvolvimento de meios de cultura alternativos para produção de endotoxinas produzidas por Bacillus thuringiensis
(2018-08-27) Oliveira, Débora Pessoa de; Bezerra, Raquel Pedrosa; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/1037675318692431
Encapsulamento de peptídeos inibidores da enzima conversora de angiotensina: uma revisão sistemática
(2022-10-04) Amorim, Andreza Pereira de; Bezerra, Raquel Pedrosa; Souza, Karoline Mirella Soares de; http://lattes.cnpq.br/1649933694798062; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/0373414973566228
Protein hydrolysates (peptides) isolated from various sources have a wide range of biological activities, such as antihypertensive. These peptides inhibit angiotensin-I converting enzyme (ACE) in the cardiovascular system contribute to the prevention and treatment of hypertension. Oral administration of this peptide can be altered by the action of gastrointestinal enzymes. Thus, encapsulation has been an alternative for preserving the activity of ACEi peptides. The purpose of this article was to systematically review studies that evaluated encapsulation of ACEi peptides. An electronic search of the Pubmed, Web of Science, Scopus databases and supplemented by a manual search was conducted from 2011 to 2022. In total, 102 articles were evaluated and only 12 fitted in the inclusion criteria. Nano/liposome is the most common delivery system, although nano/microparticles have better encapsulation efficiency (EE) value. In general, ionotropic gelation and a combination of sodium alginate and gum arabic provided the best EE value. Among nano/liposomal systems, film hydration technique and phosphatidylcholine (PC) as carrier material has been the predominant choice for ACEi peptide encapsulation, although the use of the film hydration technique showed higher EE values when, soybean phospholipids (SP) was used as carrier material. Thus, the choice of technique and material becomes a crucial step for the effective encapsulation of ACEi peptides.
Extração e caracterização de extratos lipídicos obtidos da biomassa de Tetradesmus (Scenedesmus) obliquus com propriedades antimicrobianas
(2021-07-15) Ferreira, Millena Patrício do Nascimento; Bezerra, Raquel Pedrosa; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/1713734083159044
Microalgae have become a source promising renewable energy, in addition it provides bioactive substances such as carbohydrates, proteins, vitamins and lipids. Lipids perform several biological functions and are fundamental to the survival of most living beings. Extraction is an important step in the process of obtaining lipids from microalgal biomass and can be performed in different ways in order to achieve greater yield and cost-benefit. This study performed the extraction and characterization of the lipid extract from the biomass of Tetradesmus obliquus and evaluated its antimicrobial property. Microalgae was cultivated in Erlenmeyers flasks for 15 days until it reached the stationary phase of cell growth. The dry biomass remained in contact with the solvents hexane, ethyl acetate and ethanol P.A, all with different polarities, for 48 hours in which the lipid yield and the fatty acid profile were determined by gas chromatography. Extracts of hexane (EHT), ethyl acetate (EAT) and ethanol (EET) were subjected to antimicrobial activity at concentrations of 100, 50, 25, 12.5, 6.25 and 3.12 mg/mL against bacteria Staphylococcus aureus, Klebsiella pneumoniae e Escherichia coli. EET obtained the highest lipid yield with 1.49±0.01% in the first extraction, while EAT obtained 1.22±0.02% and EHT yielded 0.52±0.03%. In a second extraction EHT doubled the yield with 1.17±0.00% and EAT managed to reach 2.47±0.00%, presenting better results with an reextraction. The essential fatty acids most present in the extracts were α-linolenic (15.4% to 19.9%) and oleic acid (5.74% to 8.93%), which are most present in the extract EHT and EAT. EAT managed to achieve better results by inhibiting the growth of all bacteria to the lowest concentration. EHT was positive until the concentration of 6.25 mg/mL and EET only managed to totally inhibit the growth of the E.coli bacteria at the concentration of 100 mg/mL. So far, it can be concluded that the ethyl acetate solvent is more suitable for extraction of T. obliquus lipids with antimicrobial activity.
Microrganismos fotossintetizantes como potencial fonte de moléculas bioativas contra Leishmania spp.: uma revisão
(2023-08-14) Silva, Sabrina Swan Souza da; Bezerra, Raquel Pedrosa; Andrade, Alexsandra Frazão de; http://lattes.cnpq.br/8560904255362766; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/8504258200413633
Leishmaniasis are infectious diseases caused by protozoan parasites of the genus Leishmania and represent a serious public health problem with global impact, affecting thousands of people every day. The drugs currently available for treatment are based on pentavalent antimonials that have adverse side effects with cases of resistance and ineffectiveness being frequently reported. Thus, photosynthetic microorganisms (microalgae and cyanobacteria) are a wide source of compounds that can be used in the treatment of various diseases, and due to their rapid growth combined with their minimum nutritional requirements. they have a reduced production cost, making them strong candidates as raw material for the development of new medicines. The search was conducted in databases such as Google Scholar, ScienceDirect, National Center for Biotechnology Infozmation (NCBI) and Virtual Health Library (VHL) using the terms alone and in combination to identify the articles: cyanobacteria, microalgae, photosynthetic microorganisms, bioactives, antileishmanial, antiprotozoal. The inclusion criteria for this review were original articles describing the antiparasitic activity of extracts or compounds isolated from cyanobacteria and microalgae against Leishmania infection. Bibliographical references of the included articles were checked to identify possible eligible articles. In total, eleven articles were selected and analyzed based on the species of microorganisms, bioactive compounds, and their minimum concentration to reduce 50% of the parasite population (IC5o). Cyanobacteria were the most studied group, with an emphasis on the genus Lyngbya, while there was only one study using three genera of microalgae (Nannochloris spp., Picochlorum sp. and Desmochloris sp.). The in vitro studies found reported the use of peptides as the main bioactive with anti-Leishmania activity, with the ticonamide A peptide, which presented the lowest ICso value (1.14 FM), and the almiramide B and almiramide C peptides, the most selective for the parasite, with IS values of 21.7 and 17.4, respectively. Therefore, peptides from photosynthetic microorganisms are a promising source for the development of future pharmacological products against Leishmania.
Produção de enzimas utilizando resíduos de café como substrato em processos fermentativos: uma revisão
(2021-12-07) Alves, Ywkelly de Lima; Bezerra, Raquel Pedrosa; Costa, Romero Marcos Pedrosa Brandão; http://lattes.cnpq.br/1797280118220965; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/2310542251305353
Microbial enzymes stand out due to their numerous biotechnological applications, and allied to this, the possibility of using residues as a substrate in the fermentation process can bring advantages in production on an industrial scale. Coffee residues, for example, have been shown to be a good means of obtaining a variety of enzymes. Thus, the objective of this work was to carry out a systematic review of the use of three different types of coffee residues for enzyme production, through fermentation processes, in order to identify the main classes of enzymes produced and the microorganisms used as fermenting agents, such as fungi, bacteria, cyanobacteria and microalgae. Thus, a bibliographic search was carried out in the databases since the last decade using the keywords “waste pulp coffee and enzyme” and, through inclusion and exclusion criteria, 26 articles were selected. About 30.76% of the works were produced in Indonesia and pointed to cellulase as the main enzyme produced. Solid state fermentation (SSF) was the most used process for the production of enzymes, representing 92.59%, and the fungi of the genus Aspergillus were most widely used in this process, with 23.07% of occurrence in the articles. Among coffee residues, pulp had the highest occurrence, appearing in 76.92% of the articles. Furthermore, fermentation time, residue volume, temperature and pH were essential parameters in the final result of obtaining the enzymes. Thus, it was observed that the coffee residue has potential as a substrate for obtaining different enzymes, mainly cellulosic ones, using fungi, especially those of the Aspergillus genus, in solid fermentation processes.
Produção, extração, purificação e caracterização de proteases fibrinolíticas produzidas por Streptomyces parvulus DPUA 1573
(2021-11-29) Nascimento, Maria Clara do; Bezerra, Raquel Pedrosa; Batista, Juanize Matias da Silva; http://lattes.cnpq.br/6699725036732885; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/5929405825655717
Due to their fibrin degradation potential, fibrinolytic proteases are a promising alternative in the pharmaceutical industry for the treatment of cardiovascular diseases, especially thrombosis. There are several sources of fibrinolytic proteases, however, the microbial sources are the ones that stand out in terms of low cost and high production rates. From their production to application, enzymes need to go through several processes, which sounds negative, making the steps more costly and late. A method capable of overcoming these problems is the aqueous two-phase system (SDFA), a process capable of reducing downstream steps. The objective of this work was to produce, purify and biochemically characterize the fibrinolytic protease produced by Streptomyces parvulus DPUA 1573. The protease was produced by submerged fermentation using agro-industrial waste or co-products. The crude extract that showed the highest enzymatic activity (passion fruit peel flour) was subjected to extraction by SDFA consisting of polyethylene glycol (PEG) and phosphate salts (potassium and sodium), following a 24 plan. After extraction by SDFA, the protease was subjected to purification by gel filtration chromatography, and already purified had its biochemical characterization performed. The protease produced by S. parvulus DPUA 1573 showed fibrinolytic activity of 15.46 U/mL and was able to form a halo of 317.31 mm2 acting on fibrin degradation. In SDFA, the fibrinolytic protease partitioned preferentially to the PEG-rich phase. The best assay selected according to the combination of the highest specific activity index, purification factor and activity yield was 16, composed of PEG 8,000 gmol-1, 17.5 v/v PEG, pH 8.0 and 15 v/v of phosphate salts. The protease activity of the enzyme was highly stimulated in the presence of iron, reaching a 55% increase in activity, and drastically decreased in the presence of the protease inhibitor 2-mercaptoethanol (91%). The optimum temperature and pH for the enzymatic activity were 40ºC and pH 7.0, respectively, keeping the enzyme activity stable between 30ºC and 60ºC and in the pH range from 7.0 to 8.5. Based on the analyzed results, it was seen that S. parvulus DPUA 1573 proved to be a good producer of fibrinolytic proteases, and the PEG/Phosphate aqueous two-phase system proved to be a great alternative for the extraction and pre-purification of fibrinolytic proteases.
Remoção do corante Azo Direct Black 22 utilizando fungos Aspergillus
(2021-12-06) Santos, Karolaine da Conceição Gama; Bezerra, Raquel Pedrosa; http://lattes.cnpq.br/1466206759539320; http://lattes.cnpq.br/8911087163041081
During the activity of the textile industrial sector, characteristic effluents are generated due to their strong coloration and, in contrast to the benefits, concerns arise from the impacts caused by the presence of dyes in the effluents. As they are difficult to degrade and have high toxicity, dyes lead to the eutrophication process and a reduction in the photosynthetic rate in water bodies, in addition to presenting toxic bioaccumulative potential. Therefore, it is essential to treat wastewater prior to release into water bodies, with the bioremediation process that employs micro-organisms to degrade such compounds as an alternative. Thus, this study aimed to investigate the ability of fungi of the genus Aspergillus to remove the tetra-azo dye Direct Black 22 (DB22). A selection of fungi from DB22 dye discoloration (50 mg/ L) was performed using 1g of live biomass of A. japonicus (URM 5620), A. niger (URM 5741) and A. niger (URM 5838) with duration 2 hours of experimentation, under at room temperature and 120 RPM. The fungi that showed the best results were A. niger (URM 5741) and A. niger (URM 5838), which in the initial 10 minutes of the experiment removed the DB22 dye by 86% and 97%, respectively. Such fungi were used with values of 1 g and 3 g of live biomass to evaluate the influence of the amount of biomass, since 1 g of biomass presented at the end of the test better dye removal, reaching the maximum discoloration of 100% and 99% for A. niger (URM 5741) and A. niger (URM 5838), respectively. The decolorizing capacity between live and dead fungal biomass (1 g) was also investigated, and it was observed that the dead biomass had the best percentage of discoloration, 66% and 96% for A. niger (URM 5741) and A. niger (URM 5838), respectively, still in the first minute of rehearsal. In this way, showing the ability of Aspergillus to remove DB22. Therefore, having seen the efficiency of application of such a filamentous fungus, it is necessary to further investigate the fungal biological mechanism in the removal of the textile dye and evaluate different test conditions to later be applied in real effluent on an industrial scale in order to contribute to the reuse of water in the harsh region of the State.