DEALI - Departamento de Alimentos
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/540
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Resultados da Pesquisa
Item Bioactive properties of Syzygium cumini (L.) skeels pulp and seed phenolic extracts.(2020) Santos, Catarina Angeli; Almeida, Felipe Alves de; Quecan, Beatriz Ximena Valencia; Gandra, Kelly Moreira Bezerra; Pereira, Patrícia Aparecida Pimenta; Cunha, Luciana Rodrigues da; Pinto, Uelinton ManoelThe emergence of bacterial strains resistant to different antibiotics has prompted the search for new sources of antimicrobial compounds. Studies have shown that jambolan [Syzygium cumini (L.) Skeels], a tropical fruit from the Mirtaceae family, contains a great variety of phytochemical compounds with high antioxidant and antimicrobial activity. This study aimed to determine the centesimal composition and physicochemical characteristics of the pulp and seed of S. cumini (L.) Skeels, as well as the content of total phenolic compounds and the antioxidant, antibacterial, antibiofilm and anti-quorum sensing (QS) activities of the phenolic extracts obtained from the pulp and the seeds of this fruit. The in vitro antibacterial and antiQS activities of active films incorporating phenolic extracts were also evaluated. Additionally, we performed molecular docking of phenolic compounds present in jambolan with the CviR QS regulator of Chromobacterium violaceum. The composition and physicochemical characteristics of the samples presented similar values to those found for the species. However, the seed phenolic extract had a higher content of phenolic compounds and antioxidant activity than the pulp. Both phenolic extracts presented antibacterial activity against Aeromonas hydrophila, C. violaceum, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica serovar Typhimurium, Serratia marcescens, Listeria monocytogenes, and Staphylococcus aureus. The seed phenolic extract was particularly inhibitory against S. aureus. The pulp phenolic extract inhibited swarming motility and biofilm formation of A. hydrophila, E. coli, and S. marcescens in sub-MIC concentrations. The pulp and seed phenolic extracts inhibited violacein production in C. violaceum. Films incorporating both phenolic extracts inhibited the growth of bacteria, particularly Pseudomonas fluorescens, L. monocytogenes, and S. aureus, as well as QS in C. violaceum. Molecular docking showed that a variety of compounds found in pulp and seed extracts of jambolan, particularly chlorogenic acid and dihydroquercetin, potentially bind CviR protein and may interfere with QS. Our results indicate that pulp and seed of jambolan are good sources of antibacterial, antibiofilm, and anti-QS compounds that can be used in the development of natural preservatives and for application in antibacterial active films.Item Acyl homoserine lactone‑based quorum sensing stimulates biofilm formation by Salmonella Enteritidis in anaerobic conditions.(2017) Almeida, Felipe Alves de; Pimentel Filho, Natan de Jesus; Pinto, Uelinton Manoel; Mantovani, Hilário Cuquetto; Oliveira, Leandro Licursi de; Vanetti, Maria Cristina DantasQuorum sensing regulates a variety of phenotypes in bacteria including the production of virulence factors. Salmonella spp. have quorum sensing systems mediated by three autoinducers (AI-1, AI-2, and AI-3). The AI-1-mediated system is incomplete in that the bacterium relies on the synthesis of signaling molecules by other microorganisms. This study aimed to evaluate the influence of the AI-1 N-dodecanoyl-DL-homoserine lactone (C12- HSL) on the growth, motility, adhesion, and biofilm formation of Salmonella enterica serovar Enteritidis PT4 578 on a polystyrene surface. Experiments were conducted at 37 °C in anaerobic tryptone soy broth supplemented with C12-HSL and/or a mixture of four synthetic furanones, at the concentration of 50 nM each. The planktonic growth, adhesion, swarming, and twitching motility were not altered in the presence of C12-HSL and/or furanones under anaerobic conditions. However, C12-HSL induced biofilm formation after 36 h of cultivation as determined by quantification of biofilm formation, by enumeration of adhered cells to polystyrene coupons, and finally by imaging the presence of multilayered cells on an epifluorescence microscope. When furanones were present in the medium, an antagonistic effect against C12-HSL on the biofilm development was observed. The results demonstrate an induction of biofilm formation in Salmonella Enteritidis by AI-1 under anaerobic conditions. Considering that Salmonella does not produce AI-1 but respond to it, C12-HSL synthesized by other bacterial species could trigger biofilm formation by this pathogen in conditions that are relevant for its pathogenesis.Item Quorum sensing regulated phenotypes in Aeromonas hydrophila ATCC 7966 deficient in AHL production.(2016) Rossi, Adriana dos Reis Ponce; Pinto, Uelinton Manoel; Ribon, Andrea de Oliveira Barros; Bazzolli, Denise Mara Soares; Vanetti, Maria Cristina DantasThe virulence of Aeromonas hydrophila is positively regulated by a quorum sensing (QS) system based on the ahyRI genes. The aim of this study was to evaluate the phenotypic characteristics related to virulence in the A. hydrophila strain ATCC 7966 in order to check if virulence traits are still functioning, despite the absence of a well characterized QS system. As expected, we were not able to detect quorum signaling AHL molecules in A. hydrophila ATCC 7966 by cross-streaking or thin layer chromatography with AHL biosensor strains. Although A. hydrophila ATCC 7966 did not produce AHLs, transcription of the ahyI and ahyR genes was observed by RT-PCR. Phenotypes generally recognized as QS-regulated in A. hydrophila were maintained in ATCC 7966; these phenotypes included proteolytic activity on casein and gelatin and amylolytic, lipolytic, and β- hemolytic activities, as well as the ability to adhere to surfaces and to form biofilms. Moreover, the addition of exogenous AHLs did not induce changes in the evaluated phenotypes. The results suggest that although this strain does not produce AHL as evaluated in this study, it maintains the phenotypes commonly associated with QS in this species indicating that other regulatory mechanisms independent of ahyRI may be in place.