http://repositorio.ufc.br/handle/riufc/347 Wed, 08 Apr 2026 09:11:53 GMT 2026-04-08T09:11:53Z http://repositorio.ufc.br/handle/riufc/85601 Título: Papel funcional da família de enzimas glicolato oxidase (GOX) e catalase (CAT) em feijão-caupi (Vigna unguiculata [L.] Walp.) na resposta ao Cowpea Severe Mosaic Virus Autor(es): Bezerra, Victor Breno Faustino Abstract: With the increase in food shortages and nutritional deficiencies, the choice of alternative crops with relevant characteristics is important. Vigna unguiculata L. is therefore a crop of great interest. However, cowpeas are still susceptible to some pathogens, such as the CowPea Severe Mosaic Virus (CPSMV). Under adverse conditions, such as infection by pathogens, one of the initial mechanisms for the stress response involves the production of reactive oxygen species. One of these molecules is hydrogen peroxide, which has its highest production rate related to Glycolate Oxidase (GOX), an enzyme in the photorespiration process, but like all reactive species, its production and consumption must be finely balanced, so there is the peroxisomal enzyme Catalase (CAT), responsible for this control during a stress phenomenon. The aim of this study was therefore to analyse the expression of GOX and CAT gene copies, at transcript and activity level, in response to CPSMV. To this end, the plant specimens were inoculated with CPSMV at three time points (16 hours, 48 hours and 144 hours). Analyses of catalase enzyme activity showed differences between the cultivars only in the initial hours (16h), in the control conditions of inoculated Pitiúba and Mock, possibly related to the initial response to the pathogen. In addition, analyses using DAB (3,3'-Diaminobenzidine) staining, MDA (Malonaldehyde) and peroxide content were used to determine the degree of oxidative stress, again with differences only between Pitiúba Mock and inoculated at 16 and 48 hours. In addition, the expression data showed differences mainly in the VuGOX1 gene in the Macaíbo cultivar, whose expression was induced during infection compared to the Mock. While VuGOX2 was the gene with the highest abundance at transcript level, showing differences between the cultivars at times of 16 and 144h, with reduced expression in inoculated Pitiúba compared to Mock 144h. Analysis of cis-elements showed regions that corroborate points raised in the discussion, mainly related to the pathogen response route and the synthesis of salicylic acid (SA). Thus, it is hoped that the results found will help breeding programmes and understanding of the resistance phenomenon. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85601 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85389 Título: Atividade antimicrobiana do óleo essencial de Croton pluriglandulosus Carn. (Euphorbiaceae) contra microrganismos de interesse clínico Autor(es): Carvalho, Rayara Joice Paulino Abstract: Fungal and bacterial infections remain significant causes of morbidity and mortality, exacerbated by increasing resistance to conventional antimicrobials. Yeasts of the genus Candida cause infections in both immunocompetent and immunocompromised individuals, while associated pathogenic bacteria are the primary cause of urinary, respiratory, and systemic infections, often resistant to multiple classes of antimicrobials. In this context, plant-derived essential oils stand out as promising therapeutic alternatives due to their antifungal and antibacterial properties. Their antimicrobial activity is mainly related to the destabilization of the plasma membrane and interference in essential metabolic processes, contributing to the fight against microbial resistance. This study aims to evaluate the antimicrobial activity and mechanisms of action of the essential oil (EO) extracted from the leaves of Croton pluriglandulosus Carn.-Torres & Riina (CpEO) on human pathogenic microorganisms in planktonic lifestyles and biofilms. The results demonstrated that the essential oil of Croton pluriglandulosus has 26 different metabolites, with elemicin (25.77%), bicyclogermacrene (9.37%), caryophyllene (8.99%), 1,3,5-trimethoxybenzene (6.86%), and hedicariol (6.21%) being the major compounds. The oil, at a concentration of 50 μg mL−1 , was able to inhibit the planktonic growth of C. krusei (89.3%) and C. parapsilosis (80.70%). Furthermore, biofilm formation was initiated in 85.5% of C. krusei and 77.9% of C. parapsilosis. There was no reduction in the biomass of the pre-formed biofilm. The prevention data were not excessive for the species C. albicans and all tested bacterial species (B. subtilis, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus e Salmonella enterica). Fluorescence microscopy analyses showed that the oil ages, causing cell membrane damage, cell death, and inducing the production of reactive oxygen species (ROS). Electron microscopy images showed high-resolution morphological damage to the cells upon contact with the oil. Furthermore, the oil did not cause hemolysis in human erythrocytes at the concentrated level. The data obtained offer a future alternative for obtaining drugs and active compounds to be used by the clinical sector for microbiological control purposes. Tipo: Dissertação Sun, 01 Jan 2023 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85389 2023-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85052 Título: Comparação entre os níveis de proteinases aspárticas e cisteínicas nos intestinos-médios das larvas de Callosobruchus maculatus e Zabrotes subfasciatus (Coleoptera: Bruchidae) Autor(es): Silva, Carlos Peres Abstract: An aspartic proteinase with characteristics similar to cathepsin D, with higher activity against hemoglobin in comparison to bovine serum albuiiiin and niaximal hydrolysis of hemoglobin at pH 3.3, was isolated from midgut homogenates of larvae of Callosobruchus maculatus through gel filtration on Sephadex G-75 followed by 1on exchange chromatography on CM-Sepharose. [...] Tipo: Dissertação Mon, 01 Jan 1990 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85052 1990-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/85046 Título: Avaliação da atividade antifúngica de proteínas ligantes a Quitina (Mo-CBP3 e Mo-CBP4) de Moringa oleifera contra fitopatógenos de cultivares economicamente relevantes Autor(es): Leite, Laís Oliveira Abstract: Phytopathogenic fungi, such as Fusarium jinanense and Colletotrichum tropicale, pose a significant threat to agriculture by causing diseases in economically important crops, such as melon and pitaya, leading to substantial production losses. Given the challenges associated with the excessive use of chemical fungicides, including microbial resistance and environmental impacts, the search for sustainable alternatives has gained prominence. In this context, plant- derived proteins with antifungal activity, such as those isolated from Moringa oleifera, emerge as promising candidates for controlling these pathogens. This study investigated the mechanisms of action of Moringa oleifera chitin binding proteins (Mo-CBP), Mo-CBP3 and Mo-CBP4, extracted from M. oleifera seeds, against F. jinanense and C. tropicale, respectively. The proteins were purified using affinity and ion-exchange chromatography, and their efficacy was evaluated through assays for minimum inhibitory concentration (MIC), cell membrane integrity, reactive oxygen species (ROS) production, intracellular content leakage, and analysis of lipid and ergosterol content. The results demonstrated that Mo-CBP3 inhibited F. jinanense (MIC = 0,25 mg/mL), while Mo-CBP4 was effective against C. tropicale (MIC = 0,25 mg/mL). Both proteins induced plasma membrane damage, reduced lipid and ergosterol content, and increased cellular permeability, confirming their potential as multifactorial antifungal agents. Although Mo-CBP3 induced moderate ROS production in F. jinanense, this effect was not observed for Mo-CBP4 in C. tropicale, suggesting distinct mechanisms of action depending on the fungal species. This study highlights the biotechnological potential of these proteins as sustainable alternatives for phytopathogen control, with possible applications in agriculture to reduce reliance on chemical fungicides. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/85046 2025-01-01T00:00:00Z