Navegando por Autor "Oliveira, Leandro Licursi de"
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Item Acyl homoserine lactone changes the abundance of proteins and the levels of organic acids associated with stationary phase in Salmonella Enteritidis(Microbial Pathogenesis, 2016-12-01) Almeida, Felipe Alvesde; Pimentel-Filho, Natan de Jesus; Carrijo, Lanna Clícia; Bento, Claudia Braga Pereira; Baracat-Pereira, Maria Cristina; Pinto, Uelinton Manoel; Oliveira, Leandro Licursi de; Vanetti, Maria Cristina DantasQuorum sensing (QS) is cell-cell communication mechanism mediated by signaling molecules known as autoinducers (AIs) that lead to differential gene expression. Salmonella is unable to synthesize the AI-1 acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. Our study aimed to evaluate the influence of AI-1 on the abundance of proteins and the levels of organic acids of Salmonella Enteritidis. The presence of N-dodecyl-homoserine lactone (C12-HSL) did not interfere on the growth or the total amount of extracted proteins of Salmonella. However, the abundance of the proteins PheT, HtpG, PtsI, Adi, TalB, PmgI (or GpmI), Eno, and PykF enhanced while the abundance of the proteins RplB, RplE, RpsB, Tsf, OmpA, OmpC, OmpD, and GapA decreased when Salmonella Enteritidis was anaerobically cultivated in the presence of C12-HSL. Additionally, the bacterium produced less succinic, lactic, and acetic acids in the presence of C12-HSL. However, the concentration of extracellular formic acid reached 20.46 mM after 24 h and was not detected when the growth was in the absence of AI-1. Considering the cultivation period for protein extraction, their abundance, process and function, as well as the levels of organic acids, we observed in cells cultivated in presence of C12-HSL a correlation with what is described in the literature as entry into the stationary phase of growth, mainly related to nitrogen and amino acid starvation and acid stress. Further studies are needed in order to determine the specific role of the differentially abundant proteins and extracellular organic acids secreted by Salmonella in the presence of quorum sensing signaling molecules.Item Acyl homoserine lactone-based quorum sensing stimulates biofilm formation by Salmonella Enteritidis in anaerobic conditions(Archives of Microbiology, 2016-11-12) 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 Antimicrobial and synergistic activity of 2, 2', 4- trihydroxybenzophenone against bacterial pathogens of poultry(Frontiers in Microbiology, 2019-03) Aranda, Martha Isabel Realpe; Gómez, Gabriel Andres Tafur; Barros, Mariana de; Santos, Marcelo Henrique dos; Oliveira, Leandro Licursi de; Pena, Junnia Luisa; Moreira, Maria Aparecida ScatamburloIn poultry farming, the spread of bacterial pathogens results in disease outbreaks causing significant economic losses to this industry. Many of these pathogenic bacteria are zoonotic and have a substantial impact on public health. Antimicrobials are essential for the prevention and treatment of these bacterial infections. However, the indiscriminate use of these agents provides favorable conditions for selection, propagation and persistence of bacteria and development of antimicrobial resistance. We developed a new antimicrobial candidate that could be used alone or in synergy with research protocols for therapeutic, prophylactic and growth promoter uses in the poultry industry. The present study aimed at evaluating the antimicrobial activity of the synthetic compound 2,2 ,4-trihydroxybenzophenone against pathogenic bacteria that cause important diseases in poultry and public health. We tested the hemolytic effect of this compound, studied its synergistic effect with conventional antimicrobials and analyzed the site of action on the bacteria. The results of our study showed antimicrobial activity of benzophenone against Gram-positive and Gram-negative bacteria with a similar effect in ATCC (American type culture collection) and field isolates. This compound was non- hemolytic. 2,2 ,4- trihydroxybenzophenone acted on the bacterial cell wall. We identified the synergistic effect between 2,2 ,4-trihydroxybenzophenone and bacitracin, this effect indicate that antimicrobial synergism may be useful for the treatment of necrotic enteritis in poultry. This compound may also be used as a growth promoter by reducing the dose of bacitracin and thus decreasing the pressure of bacterial resistance in poultry which would circumvent the development of cross-resistance in humans.Item Bacteriophage isolated from sewage eliminates and prevents the establishment of Escherichia Coli Biofilm(Advanced Pharmaceutical Bulletin, 2018-02-20) Ribeiro, Karla Veloso Gonçalves; Ribeiro, Cleberson; Dias, Roberto Sousa; Cardoso, Silvia Almeida; Paula, Sérgio Oliveira de; Zanuncio, Jose Cola; Oliveira, Leandro Licursi deBiofilm growth exerts a negative impact on industry and health, necessitating the development of strategies to control. The objective of this work was study the lytic activity of the phage isolated from the sewage network in the formation and degradation of Escherichia coli biofilms. E. coli cultures were incubated in 96-well polystyrene microplates under controlled conditions to evaluate the biofilm formation. The E. coli cultures and established biofilms were treated with the suspensions of the vB_EcoM-UFV017 (EcoM017) bacteriophage obtained from sewage for 24 hours. The E. coli bacterial density was measured using absorbance at 600 nm and the biofilms were measured by crystal violet staining. Polystyrene coupons were used as support for Scanning Electron Microscopy and Confocal Microscopy to evaluate biofilm formation. The E. coli strains formed biofilms in polystyrene microplates after 48 hours’ incubation. The highest EcoM017 phage titer, in the prevention and degradation experiments, reduced the bacterial growth and the quantity of biofilm formed by E. coli in 90.0% and 87.5%, respectively. The minimum dose capable of reducing the biofilms of this bacterium was 101 PFU/mL after 24 hours. The preformed E. coli biofilm mass was reduced 79% post exposure to the phage in the degradation assay. Microscopic analysis confirmed the results obtained in the plates assays. The EcoM017 phage prevented biofilm formation and degraded the E. coli-established ones. The EcoM017 phage isolated from sewage can reduce bacterial attachment and lyse the E. coli associated biofilm cells, offering biotechnological potential applicability for this phage.Item Beneficial effects of physical activity in an HIV-infected woman with lipodystrophy: a case report(Journal of Medical Case Reports, 2011-09-05) Mendes, Edmar Lacerda; Andaki, Alynne Christian Ribeiro; Natali, Antônio José; Amorim, Paulo Roberto dos Santos; Oliveira, Leandro Licursi de; Paula, Sérgio Oliveira de; Brito, Ciro José; Córdova, Cláudio; Mutimura, EugeneLipodystrophy is common in patients infected with human immunodeficiency virus receiving highly active antiretroviral therapy, and presents with morphologic changes and metabolic alterations that are associated with depressive behavior and reduced quality of life. We examined the effects of exercise training on morphological changes, lipid profile and quality of life in a woman with human immunodeficiency virus presenting with lipodystrophy. A 31-year-old Latin-American Caucasian woman infected with human immunodeficiency virus participated in a 12-week progressive resistance exercise training program with an aerobic component. Her weight, height, skinfold thickness, body circumferences, femur and humerus diameter, blood lipid profile, maximal oxygen uptake volume, exercise duration, strength and quality of life were assessed pre-exercise and post-exercise training. After 12 weeks, she exhibited reductions in her total subcutaneous fat (18.5%), central subcutaneous fat (21.0%), peripheral subcutaneous fat (10.7%), waist circumference (WC) (4.5%), triglycerides (9.9%), total cholesterol (12.0%) and low-density lipoprotein cholesterol (8.6%). She had increased body mass (4.6%), body mass index (4.37%), humerus and femur diameter (3.0% and 2.3%, respectively), high-density lipoprotein cholesterol (16.7%), maximal oxygen uptake volume (33.3%), exercise duration (37.5%) and strength (65.5%). Quality of life measures improved mainly for psychological and physical measures, independence and social relationships. These findings suggest that supervised progressive resistance exercise training is a safe and effective treatment for evolving morphologic and metabolic disorder.Item A C-Type Lectin from Bothrops jararacussu Venom disrupts staphylococcal biofilms(Plos One, 2015-03-26) Klein, Raphael Contelli; Fabres-Klein, Mary Hellen; Oliveira, Leandro Licursi de; Feio, Renato Neves; Malouin, François; Ribo, Andréa de Oliveira BarrosBovine mastitis is a major threat to animal health and the dairy industry. Staphylococcus aureus is a contagious pathogen that is usually associated with persistent intramammary infections, and biofilm formation is a relevant aspect of the outcome of these infections. Several biological activities have been described for snake venoms, which led us to screen secretions of Bothrops jararacussu for antibiofilm activity against S. aureus NRS155. Crude venom was fractionated by size-exclusion chromatography, and the fractions were tested against S. aureus. Biofilm growth, but not bacterial growth, was affected by several fractions. Two fractions (15 and 16) showed the best activities and were also assayed against S. epidermidis NRS101. Fraction 15 was identified by TripleTOF mass spectrometry as a galactose-binding C-type lectin with a molecular weight of 15 kDa. The lectin was purified from the crude venom by D-galactose affinity chromatography, and only one peak was observed. This pure lectin was able to inhibit 75% and 80% of S. aureus and S. epidermidis biofilms, respectively, without affecting bacterial cell viability. The lectin also exhibited a dose-dependent inhibitory effect on both bacterial biofilms. The antibiofilm activity was confirmed using scanning electron microscopy. A pre-formed S. epidermidis biofilm was significantly disrupted by the C-type lectin in a time-dependent manner. Additionally, the lectin demonstrated the ability to inhibit biofilm formation by several mastitis pathogens, including different field strains of S. aureus, S. hyicus, S. chromogenes, Streptococcus agalactiae, and Escherichia coli. These findings reveal a new activity for C-type lectins. Studies are underway to evaluate the biological activity of these lectins in a mouse mastitis model.Item Comparison of gene expression of Toll-like receptors and cytokines between Piau and commercial line (Landrace × Large White crossbred) pigs vaccinated against Pasteurella multocida type D(Research in Veterinary Science, 2017-05-12) Sousa, Katiene Régia Silva; Ribeiro, André Mauric Frossard; Dantas, Waleska de Melo Ferreira; Oliveira, Leandro Licursi de; Gasparino, Eliane; Guimarães, Simone Eliza FacioniWe aimed to compare Toll-like receptors (TLR) and cytokines expression in local Piau breed and a Commercial line (Landrace × Large White crossbred) pigs in response to vaccination against Pasteurella multocida type D. Seronegative gilts for Pasteurella multocida type D and Mycoplasma hyopneumoniae were used, from which peripheral blood mononuclear cells (PBMC) were collected in four time points (T0, T1, T2 and T3; before and after each vaccination dose). For bronchoalveolar lavage fluid cells (BALF), we set groups of vaccinated and unvaccinated animals for both genetic groups. Gene expression was evaluated on PBMC and BALF. In PBMC, when we analyzed time points within breeds, significant differences in expression for TLRs and cytokines, except TGFβ, were observed for Commercial animals. For the Piau pigs, only TGFβ showed differential expression. Comparing the expression among genetic groups, the Commercial pigs showed higher expression for TLRs after first vaccination dose, while for IL2, IL6, IL12 and IL13, higher expression was also observed in T3 and IL8 and IL10, in T1 and T3. Still comparing the breeds, the crossbred animals showed higher expression for TNFα in T1 and T2, while for TGFβ only in T2. For gene expression in BALF, vaccinated Commercial pigs showed higher expression of TLR6, TLR10, IL6, IL8, IL10, TNFα and TGFβ genes than vaccinated Piau pigs. The Commercial line pigs showed higher sensitivity to vaccination, while in local Piau breed lower responsiveness, which may partly explain genetic variability in immune response and will let us better understand the tolerance/susceptibility for pasteurellosis.Item Conscientização dos produtores de leite da Zona da Mata Mineira sobre métodos de prevenção da mastite bovina e isolamento dos seus agentes etiológicos(Brazilian Journal of Sustainable Agriculture, 2011-12) Dias, Roberto Sousa; Duarte, Vinicius Silva; Favaro, Victor Lopes Ribeiro; Mantovani, Hilário Cuquetto; Silva, Cynthia Canêdo da; Silva, Eduardo de Almeida Marques da; Oliveira, Leandro Licursi de; Paula, Sérgio Oliveira DeA mastite causa perda da qualidade do leite e riscos à saúde dos consumidores em virtude da presença de resíduos de antibióticos e microrganismos patogênicos, além de sérios prejuízos econômicos tanto para o produtor quanto para a indústria de laticínios. O conhecimento referente aos agentes causadores da doença, à sua evolução clínica e a fatores relacionados com o estabelecimento da infecção deve ser colocado em prática em programas de controle e prevenção da doença, visando o treinamento dos produtores, principalmente em respeito ao manejo adequado de ordenha. Neste trabalho, buscamos conscientizar produtores de leite da Zona da Mata mineira sobre a importância do controle e prevenção de mastite bovina e determinar seus principais agentes etiológicos. Identificamos 3,3% de casos de mastite clínica, 15% de subclínica e 81,7% de tetos sadios em vacas leiteiras da região. Como principais agentes etiológicos, foram isolados o Staphylococcus aureus em 28,52% dos casos e o Staphylococcus sp., coagulase negativa, em 14,83%. Observamos também que poucos produtores da região possuem conhecimentos básicos sobre os métodos de prevenção e controle da mastite. Sendo assim, muitos carecem de programas de assistência técnica especializada, o que seria útil para o desenvolvimento de suas comunidades.Item Differential cellular immune response of Galleria mellonella to Actinobacillus pleuropneumoniae(Cell and Tissue Research, 2017-07-08) Blanco, Luis Andrés Arteaga; Crispim, Josicelli Souza; Fernandes, Kenner Morais; Oliveira, Leandro Licursi de; Pereira, Monalessa Fábia; Bazzolli, Denise Mara Soares; Martins, Gustavo FerreiraIn the present work, we have investigate the cellular immune response of Galleria mellonella larvae against three strains of the gram-negative bacterium Actinobacillus pleuropneumoniae: low-virulence (780), high-virulence (1022) and the serotype 8 reference strain (R8). Prohemocytes, plasmatocytes, granulocytes, oenocytoids and spherulocytes were distinguished according to their size and morphology, their molecular markers and dye-staining properties and their role in the immune response. Total hemocyte count, differential hemocyte count, lysosome activity, autophagic response, cell viability and caspase-3 activation were determined in circulating hemocytes of naive and infected larvae. The presence of the autophagosome protein LC3 A/B within the circulating hemocytes of G. mellonella was dependent on and related to the infecting A. pleuropneumoniae strain and duration of infection. Hemocytes treated with the high-virulence strain expressed higher levels of LC3 A/B, whereas treatment with the low-virulence strain induced lower expression levels of this protein in the cells. Moreover, our results showed that apoptosis in circulating hemocytes of G. mellonella larvae after exposure to virulent bacterial strains occurred simultaneously with excessive cell death response induced by stress and subsequent caspase-3 activation.Item Evaluation of antiulcerogenic activity of aqueous extract of Brassica oleracea var. capitata (cabbage) on Wistar rat gastric ulceration(Arquivos de Gastroenterologia, 2011-05-24) Carvalho, Camilo Amaro de; Fernandes, Kenner Moraes; Matta, Sérgio Luiz Pinto; Oliveira, Leandro Licursi de; Fonseca, Cláudio César; Silva, Marcelo Barreto daThe cabbage (Brassica oleraceae var. capitata) is an herbaceous and leafy plant which belongs to the Brassicaceae family, native to coastal southern and Western Europe. Used in cooking for its nutritional value also has known anti-inflammatory activity. We studied the antiulcerogenic activity of aqueous extract of Brassica oleracea var. capitata (AEB) in order to validate ethnobotanical claims regarding the plant use in the gastric disorders. Acute gastric ulcers were induced in rats by the oral administration of acetylsalicylic acid. The gastroprotective potential of the AEB (0.250, 0.500 and 1.000 mg.kg-1/body weight) was compared with omeprazole (20 mg.kg-1/body weight). The stomach analysis indicated that treatment with AEB inhibited the gastric damage. The gastroprotective activity as evidenced by its significant inhibition in the formation of ulcers induced by chemical agent with a maximum of 99.44% curation (250 mg.kg-1 body weight) in acetylsalicylic acid-induced ulcers. The AEB demonstrated good antiulcerogenic activities which justify the inclusion of this plant in the management of gastric disorders. Further experiments are underway to determine which antiulcer mechanisms involved in gastroprotection.Item Exposure to deltamethrin induces oxidative stress and decreases of energy reserve in tissues of the Neotropical fruit-eating bat Artibeus lituratus(Ecotoxicology and Environmental Safety, 2017-11-09) Oliveira, Jerusa Maria; Losano, Nicole Fontes; Condessa, Suellen Silva; Freitas, Renata Maria Pereira de; Cardoso, Silvia Almeida; Freitas, Mariella Bontempo; Oliveira, Leandro Licursi deDeltamethrin (DTM) is a synthetic pyrethroid insecticide highly used by farmers and home users. This pesticide has lipophilic properties that facilitate a high absorption and can cause toxicity in non-target organisms. During foraging, the fruit-eating bats Artibeus lituratus are exposed to pesticides. However, the knowledge of the toxicity of pesticides on the physiology of bats is relatively scarce. This study aimed to check the toxicity of short-term exposure to low concentration of DTM on fruit-eating bat A. lituratus. After seven days of exposure to two doses of DTM (0.02 and 0.04 mg/kg of papaya), the fruit bats showed an increase in the enzyme aspartate aminotransferase, alanine aminotransferase, and hyperglycemia. The liver and pectoral muscle presented oxidative stress. In the liver, the hydrogen peroxide (H2O2) and nitric oxide (NO) were increased as well as the antioxidant glutathione (GSH), the activity of glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) but in a lesser extent. Yet, total lipids were increased while hepatic glycogen content is reduced. The pectoral muscle showed NO, SOD, CAT, malondialdehyde (MDA), and carbonyl increased protein levels in both concentrations of DTM. All these results show that low doses of DTM can cause hepatic and muscular toxicity and induce changes in carbohydrate metabolism. Physiological changes caused by exposure to DTM in bats may have direct consequences in flight capacity, reproduction, and metabolism of these animals.Item Higher plasma lipopolysaccharide concentrations are associated with less favorable phenotype in overweight/obese men(European Journal of Nutrition, 2014-12-18) Moreira, Ana Paula Boroni; Alves, Raquel Duarte Moreira; Teixeira, Tatiana Fiche Salles; Macedo, Viviane Silva; Oliveira, Leandro Licursi de; Costa, Neuza Maria Brunoro; Bressan, Josefina; Peluzio, Maria do Carmo Gouveia; Mattes, Richard; Alfenas, Rita de Cássia GonçalvesLipopolysaccharide (LPS) from the outer membrane of gram-negative bacteria might be an inflammation trigger in adipose tissue. It has recently been proposed that there is a link between adipose tissue distribution and blood LPS. However, the number of studies on this topic is scarce, and further investigation in humans is required. In this study, we explored the association between plasma LPS concentrations and body fat distribution, as well as the biochemical parameters that may indicate the presence of metabolic disorders. Sixty-seven young adult men with body mass index of 26–35 kg/m2 were evaluated. Anthropometry, body composition and body fat distribution, blood pressure, energy expenditure, physical activity level, dietary intake, and biochemical parameters were assessed. Men with median plasma LPS ≥ 0.9 EU/mL presented higher sagittal abdominal diameter, trunk fat percentage, and android fat percentage, and mass, insulin and alanine aminotransferase concentrations, homeostasis model assessment of insulin resistance (HOMA-IR), and beta cell dysfunction (HOMA-B) than those with lower plasma LPS. LPS correlated positively with the trunk fat percentage, and android fat percentage, and mass, insulin, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase concentrations, as well as HOMA-IR and HOMA-B. Our results suggest that a higher plasma LPS concentration is associated with a less favorable phenotype as characterized by higher central adiposity, higher values of HOMA-IR, and beta cell function impairment in overweight/obese men.Item Infecção experimental em bovinos: cinética da produção de imunoglobulinas IgM e IgG contra cisticercose bovina e resposta inflamatória(Semina: Ciências Agrárias, 2014-08-11) Guimarães-Peixoto, Rafaella Paola Meneguete dos; Pinto, Paulo Sérgio de Arruda; Benjamin, Laércio dos Anjos; Oliveira, Leandro Licursi de; Marcon, Lucas; Santos, Tatiane de Oliveira; Silva, Letícia Ferreira da; Acevedo-Nieto, Emílio CamposA cisticercose bovina é uma zoonose que acomete humanos em sua forma adulta (teníase) e em sua forma larvar encontra-se inserida na musculatura de bovinos infectados (cisticercos). Ainda não está totalmente esclarecido como ocorre a resposta imune animal frente a infecção por cisticercos, sendo necessário sua total compreensão para aprimoramento de testes diagnósticos e prevenção da doença. Este trabalho teve o objetivo de avaliar preliminarmente a evolução da resposta imune de nove bovinos experimentalmente infectados com 120.000 ovos de Taenia saginata, comparando com achados da resposta celular por meio da microscopia óptica. Do total de animais, cinco apresentaram semelhança na cinética de produção de anticorpos contra as formas metacestóides (cisticercos), com elevação máxima dos níveis séricos de IgG e IgM. Quatro bovinos apresentaram uma resposta imunológica diferente da maioria: dois animais uma resposta tardia à infecção pelos cisticercos, e nos demais não foi observado aumento significativo de anticorpos. Em relação à resposta celular, foi possível constatar predominância de células inflamatórias nas lesões decorrentes de cisticercosviáveis, enquanto, na maioria dos cisticercos inviáveis havia células reparadoras de tecido e presença de corpúsculos calcários. A quantidade migratória de corpúsculos calcáreos está relacionada com o estádio de morte do parasito. É importante a associação desses achados para compreensão da resposta imune de bovinos frente a cisticercose.Item Kefir reduces the incidence of pre-neoplastic lesions in an animal model for colorectal cancer(Journal of Functional Foods, 2019-02) Reis, Sandra Aparecida dos; Conceição, Lisiane Lopes da; Dias, Mariana Moura e; Siqueira, Nathane Paes; Rosa, Damiana Diniz; Oliveira, Leandro Licursi de; Matta, Sérgio Luis Pinto da; Peluzio, Maria do Carmo GouveiaThis study aimed to evaluate the effect of regular consumption of milk kefir on the development of pre-neoplastic colonic lesions. Thirty Wistar rats received water (Control group) or milk (Milk group) or kefir (Kefir group) during five weeks. After that, colonic lesions were chemically induced and the treatments continued for more thirteen weeks. The regular consumption of kefir was able to reduce the incidence of aberrant crypt foci by 36%. Also, the consumption of kefir increased the cecal concentration of short chain fatty acids; reduced the lactulose/mannitol ratio; promoted an increase in the colonic concentration of TNF-α and IL-1β, and the enzyme catalase in comparison with the control group. Thus, kefir reduced the development of lesions, probably by increasing the production of short chain fatty acids; reduction of intestinal permeability; immunomodulation and improvement of colonic antioxidant activitItem Lactobacillus curvatus UFV-NPAC1 and other lactic acid bacteria isolated from calabresa, a fermented meat product, present high bacteriocinogenic activity against Listeria monocytogenes(BMC Microbiology, 2019) Castilho, Nathália Parma Augusto; Colombo, Monique; Oliveira, Leandro Licursi de; Todorov, Svetoslav Dimitrov; Nero, Luís AugustoBacteriocins produced by lactic acid bacteria (LAB) can be considered as viable alternatives for food safety and quality, once these peptides present antimicrobial activity against foodborne pathogens and spoilage bacteria. Fermented foods, such as artisanal sausages and cured meats, are relevant sources of LAB strains capable of producing novel bacteriocins, with particular interest by the food industry.Three LAB strains (firstly named as Lactobacillus curvatus 12, L. curvatus 36 and Weissella viridescens 23) were obtained from calabresa by presenting promising bacteriocinogenic activity, distinct genetic profiles (rep-PCR, RAPD, bacteriocin-related genes) and wide inhibitory spectrum. Among these strains, L. curvatus 12 presented higher bacteriocin production, reaching 25,000 AU/mL after incubation at 25, 30 and 37 °C and 6, 9 and 12 h. Partially purified bacteriocins from L. curvatus 12 kept their inhibitory activity after elution with isopropanol at 60% (v/v). Bacteriocins produced by this strain were purified by HPLC and sequenced, resulting in four peptides with 3102.79, 2631.40, 1967.06 and 2588.31 Da, without homology to known bacteriocins.LAB isolates obtained from calabresa presented high inhibitory activity. Among these isolates, bacteriocins produced by L. curvatus 12, now named as L. curvatus UFV-NPAC1, presented the highest inhibitory performance and the purification procedures revealed four peptides with sequences not described for bacteriocins to date.Item Leishmania chagasi heparin-binding protein: Cell localization and participation in L. chagasi infection(Molecular and Biochemical Parasitology, 2015-12-21) Martins, Thaís Viana Fialho; Carvalho, Thaís Vieira de; Oliveira, Claudia Vânia Miranda de; Paula, Sérgio Oliveira de; Cardoso, Sílvia Almeida; Oliveira, Leandro Licursi de; Silva, Eduardo de Almeida Marques-daVisceral leishmaniasis is a fatal human disease caused by the intracellular protozoan parasite Leishmania chagasi that is captured by host cells in a process involving classics receptors mediated phagocytosis. The search for molecules involved in this process is important to design strategies to disease control. In this work, we verified the presence of heparin-binding protein (HBP) in L. chagasi promastigotes forms. HBP is a lectin of the group of ubiquitous proteins, whose main characteristic is to bind to carbohydrates present in glycoproteins or glycolipids, which is poorly studied in Leishmania species. L. chagasi HBP (HBPLc) was purified by affinity chromatography using heparin–agarose column in FPLC automated system. Its localization in the parasite was assessed by immunolabeling and electronic transmission microscopy tests using anti-HBPLc polyclonal antibodies, which showed HBP spread over the parasite outer surface and internally next to the kynetoplast. In addition, we verified that HBPLc participates in the process of parasite infection, since its blocking with heparin generated a partial reduction in the internalization of Leishmania by RAW macrophages “in vitro”. According to these results, it is believed that, in further “in vivo” studies, interference on this parasitic protein may provide us prophylactic and therapeutic alternatives against visceral leishmaniasis.Item Lipophosphoglycan 3 From Leishmania infantum chagasi Binds Heparin With Micromolar Affinity(Bioinformatics and Biology Insights, 2018-02-14) Martins, Thaís Viana Fialho; Zeraik, Ana Eliza; Alves, Natália Oliveira; Oliveira, Leandro Licursi de; Mendes, Tiago Antônio de Oliveira; DeMarco, Ricardo; Marques-da-Silva, Eduardo de AlmeidaLeishmania infantum chagasi is an intracellular protozoan parasite responsible for visceral leishmaniasis, a fatal disease in humans. Heparin-binding proteins (HBPs) are proteins that bind to carbohydrates present in glycoproteins or glycolipids. Evidence suggests that HBPs present on Leishmania surface participate in the adhesion and invasion of parasites to tissues of both invertebrate and vertebrate hosts. In this study, we identified the product with an HSP90 (heat shock protein 90) domain encoded by lipophosphoglycan (LPG3) gene as a L infantum chagasi HBP (HBPLc). Structural analysis using the LPG3 recombinant protein suggests that it is organized as a tetramer. Binding analysis confirms that it is capable of binding heparin with micromolar affinity. Inhibition of adenosine triphosphatase activity in the presence of heparin, molecular modeling, and in silico docking analysis suggests that heparin-binding site superimposes with the adenosine triphosphate–binding site. Together, these results show new properties of LPG3 and suggest an important role in leishmaniasis.Item N-dodecanoyl-homoserine lactone influences the levels of thiol and proteins related to oxidation-reduction process in Salmonella(PLOS ONE, 2018-10-10) Almeida, Felipe Alves de; Carneiro, Deisy Guimarães; Barros, Edvaldo; Pinto, Uelinton Manoel; Oliveira, Leandro Licursi de; Vanetti, Maria Cristina Dantas; Mendes, Tiago Antônio de OliveiraQuorum sensing is a cell-cell communication mechanism mediated by chemical signals that leads to differential gene expression in response to high population density. Salmonella is unable to synthesize the autoinducer-1 (AI-1), N-acyl homoserine lactone (AHL), but is able to recognize AHLs produced by other microorganisms through SdiA protein. This study aimed to evaluate the fatty acid and protein profiles of Salmonella enterica serovar Enteritidis PT4 578 throughout time of cultivation in the presence of AHL. The presence of N-dodecanoyl-homoserine lactone (C12-HSL) altered the fatty acid and protein profiles of Salmonella cultivated during 4, 6, 7, 12 and 36 h in anaerobic condition. The profiles of Salmonella Enteritidis at logarithmic phase of growth (4 h of cultivation), in the presence of C12-HSL, were similar to those of cells at late stationary phase (36 h). In addition, there was less variation in both protein and fatty acid profiles along growth, suggesting that this quorum sensing signal anticipated a stationary phase response. The presence of C12-HSL increased the abundance of thiol related proteins such as Tpx, Q7CR42, Q8ZP25, YfgD, AhpC, NfsB, YdhD and TrxA, as well as the levels of free cellular thiol after 6 h of cultivation, suggesting that these cells have greater potential to resist oxidative stress. Additionally, the LuxS protein which synthesizes the AI-2 signaling molecule was differentially abundant in the presence of C12-HSL. The NfsB protein had its abundance increased in the presence of C12-HSL at all evaluated times, which is a suggestion that the cells may be susceptible to the action of nitrofurans or that AHLs present some toxicity. Overall, the presence of C12-HSL altered important pathways related to oxidative stress and stationary phase response in Salmonella.Item Potential antileukemia effect and structural analyses of SRPK inhibition by N-(2- (Piperidin-1-yl)-5-(Trifluoromethyl)Phenyl) isonicotinamide (SRPIN340)(Plos One, 2014-04-08) Siqueira, Raoni Pais; Barbosa, Éverton de Almeida Alves; Polêto, Marcelo Depólo; Righetto, Germanna Lima; Seraphim, Thiago Vargas; Salgado, Rafael Locatelli; Ferreira, Joana Gasperazzo; Oliveira, Leandro Licursi de; Laranjeira, Angelo Brunelli Albertoni; Almeida, Márcia Rogéria; Fietto, Juliana Lopes Rangel; Kobarg, Jörg; Oliveira, Eduardo Basílio de; Teixeira, Robson Ricardo; Borges, Júlio César; Silva Júnior, Abelardo; Bressan, Gustavo Costa; et al.Dysregulation of pre-mRNA splicing machinery activity has been related to the biogenesis of several diseases. The serine/arginine-rich protein kinase family (SRPKs) plays a critical role in regulating pre-mRNA splicing events through the extensive phosphorylation of splicing factors from the family of serine/arginine-rich proteins (SR proteins). Previous investigations have described the overexpression of SRPK1 and SRPK2 in leukemia and other cancer types, suggesting that they would be useful targets for developing novel antitumor strategies. Herein, we evaluated the effect of selective pharmacological SRPK inhibition by N-(2-(piperidin-1-yl)-5-(trifluoromethyl)phenyl)isonicotinamide (SRPIN340) on the viability of lymphoid and myeloid leukemia cell lines. Along with significant cytotoxic activity, the effect of treatments in regulating the phosphorylation of the SR protein family and in altering the expression of MAP2K1, MAP2K2, VEGF and FAS genes were also assessed. Furthermore, we found that pharmacological inhibition of SRPKs can trigger early and late events of apoptosis. Finally, intrinsic tryptophan fluorescence emission, molecular docking and molecular dynamics were analyzed to gain structural information on the SRPK/SRPIN340 complex. These data suggest that SRPK pharmacological inhibition should be considered as an alternative therapeutic strategy for fighting leukemias. Moreover, the obtained SRPK-ligand interaction data provide useful structural information to guide further medicinal chemistry efforts towards the development of novel drug candidates.Item Prevalence of vitamin D deficiency and its relationship with factors associated with recurrent wheezing(Jornal Brasileiro de Pneumologia, 2019) Peçanha, Mirna Brito; Freitas, Rodrigo de Barros; Moreira, Tiago Ricardo; Silva, Luiz Sérgio; Oliveira, Leandro Licursi de; Cardoso, Silvia AlmeidaTo determine the prevalence of vitamin D deficiency/insufficiency in children 0-18 years of age with recurrent wheezing and/or asthma residing in the microregion of Viçosa, Minas Gerais, Brazil, and treated at a referral center, and to determine its association with major risk factors for wheezing. A cross-sectional study was performed using a semi-structured questionnaire, which was administered by trained interviewers to the legal guardians of the study participants. Data were obtained regarding general characteristics of recurrent wheezing; general sociodemographic, environmental, and biologic factors; and atopy-related factors. The magnitude of the statistical association was assessed by calculating ORs and their corresponding 95% CIs by using multiple logistic regression. We included 124 children in the study. The prevalence of vitamin D deficiency/insufficiency in the sample was 57.3%. Vitamin D deficiency/insufficiency was found to be associated with wheezing in the first year of life, personal history of atopic dermatitis, environmental pollution, and vitamin D supplementation until 2 years of age. The prevalence of vitamin D deficiency/insufficiency was high in our sample. Vitamin D concentrations were directly associated with vitamin D supplementation until 2 years of age and were inversely associated with wheezing events in the first year of life, personal history of atopic dermatitis, and environmental pollution.