DEFAR - Artigos publicados em periódicos

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3-beta-(Stearyloxy)olean-12-ene from Austroplenckia populnea : structure elucidation by 2D-NMR and quantitative 13C-NMR spectroscopy.
(2003) Vieira Filho, Sidney Augusto; Duarte, Lucienir Pains; Silva, Grácia Divina de Fátima; Howarth, O. W.; Lula, Ivana Silva
3 -(Stearyloxy)olean-12-ene was isolated from a hexane extract of Austroplenckia populnea Reiss (Celastraceae) leaves. The structure was solved by means of quantitative 13C-NMR, HMBC, HMQC, COSY, NOESY, and NOE difference spectra. The mass spectrum showed an [M 1] ion peak at m/z 693, and the molecular formula C48H84O2 was confirmed by combustion analysis.
7-Chloroquinolinotriazoles : synthesis by the azide-alkyne cycloaddition click chemistry, antimalarial activity, cytotoxicity and SAR studies.
(2014) Pereira, Guilherme Rocha; Brandão, Geraldo Célio; Arantes, Lucas Micquéias; Oliveira Junior, Haliton Alves de; Paula, Renata Cristina de; Nascimento, Maria Fernanda Alves do; Santos, Fábio Mendes dos; Rocha, Ramon Kleber da; Lopes, Júlio César Dias; Oliveira, Alaíde Braga de
Twenty-seven 7-chloroquinolinotriazole derivatives with different substituents in the triazole moiety were synthesized via copper-catalyzed cycloaddition (CuAAC) click chemistry between 4-azido-7- chloroquinoline and several alkynes. All the synthetic compounds were evaluated for their in vitro activity against Plasmodium falciparum (W2) and cytotoxicity to Hep G2A16 cells. All the products disclosed low cytotoxicity (CC50 > 100 mM) and five of them have shown moderate antimalarial activity (IC50 from 9.6 to 40.9 mM). As chloroquine analogs it was expected that these compounds might inhibit the heme polymerization and SAR studies were performed aiming to explain their antimalarial profile. New structural variations can be designed on the basis of the results obtained.
ACE inhibition by astilbin isolated from Erythroxylum gonocladum (Mart.) O.E. Schulz.
(2010) Lucas Filho, Milton Dayrell; Silva, Grazielle Caroline da; Côrtes, Steyner de França; Guia, Thiago Rennó dos Mares; Ferraz, Vany Perpetua; Serra, Carla Penido; Braga, Fernão Castro
Erythroxylum species have several traditional uses in different countries, including the treatment of hypertension. The ethanol extract from E. gonocladum aerial parts, a species endemic to the Brazilian cerrado, elicited a concentration-dependent inhibition of angiotensin converting enzyme (ACE) (pIC50=4.53±0.05). Extract fractionation led to the isolation of two compounds, whose structures were assigned by spectrometric data as astilbin and β-sitosterol, along with a mixture of palmitic, stearic and linolenic acids. This is the first report on the occurrence of these compounds on E. gonocladum. Astilbin promoted significant ACE inhibition in vitro (pIC50=5.86±0.33) and its activity did not differ from captopril, when both compounds were assayed at 10 μM concentration.
Ações de saúde e económicas como resposta à pandemia do SARS-CoV-2 no Brasil.
(2020) Santi, Valmir de; Campesatto, Eliane Aparecida; Nascimento, Renata Cristina Rezende Macedo do; Uehara, Wilson Hiroshi de Oliveira
Activation of the ET-1/ETA pathway contributes to erectile dysfunction associated with mineralocorticoid hypertension.
(2008) Carneiro, Fernando Silva; Nunes, Kenia Pedrosa; Vitorino, Fernanda Regina Casagrande Giachini; Lima, Victor Vitorino; Carneiro, Zidonia N.; Nogueira, Edson F.; Leite, Romulo; Ergul, Adviye; Rainey, William E.; Webb, Robert Clinton; Passaglia, Rita de Cassia Aleixo Tostes
Introduction. The cavernosal tissue is highly responsive to endothelin-1 (ET-1), and penile smooth muscle cells not only respond to but also synthesize ET-1. Aim. Considering that ET-1 is directly involved in end-organ damage in salt-sensitive forms of hypertension, we hypothesized that activation of the ET-1/ETA receptor pathway contributes to erectile dysfunction (ED) associated with mineralocorticoid hypertension. Methods. Wistar rats were uninephrectomized and submitted to deoxycorticosterone acetate (DOCA)-salt treatment for 5 weeks. Control (Uni [uninephrectomized control]) animals were uninephrectomized and given tap water. Uni and DOCA-salt rats were simultaneously treated with vehicle or atrasentan (ETA receptor antagonist, 5 mg/ Kg/day). Cavernosal reactivity to ET-1, phenylephrine (PE), ETB receptor agonist (IRL-1620) and electric field stimulation (EFS) were evaluated in vitro. Expression of ROCKa, ROCKb, myosin phosphatase target subunit 1 (MYPT-1), and extracellular signal-regulated kinase 1/2 (ERK 1/2) were evaluated by western blot analysis. ET-1 and ETA receptor mRNA expression was evaluated by real-time reverse-transcriptase polymerase chain reaction. Voltage-dependent increase in intracavernosal pressure/mean arterial pressure (ICP/MAP) was used to evaluate erectile function in vivo. Main Outcome Measure. ETA receptor blockade prevents DOCA-salt-associated ED. Results. Cavernosal strips from DOCA-salt rats displayed augmented preproET-1 expression, increased contractile responses to ET-1 and decreased relaxation to IRL-1620. Contractile responses induced by EFS and PE were enhanced in cavernosal tissues from DOCA-salt hypertensive rats. These functional changes were associated with increased activation of the RhoA/Rho-kinase and ERK 1/2 pathways. Treatment of rats with atrasentan completely prevented changes in cavernosal reactivity in DOCA-salt rats and restored the decreased ICP/MAP, completely preventing ED in DOCA-salt rats. Conclusion. Activation of the ET-1/ETA pathway contributes to mineralocorticoid hypertension-associated ED. ETA receptor blockade may represent an alternative therapeutic approach for ED associated with salt-sensitive hypertension and in pathological conditions where increased levels of ET-1 are present.
Activity of alkaloids from Aspidosperma nitidum against Leishmania (Leishmania) amazonensis.
(2022) Veiga, Andreza do Socorro Silva da; Silveira, Fernando Tobias; Silva, Edilene Oliveira da; Diniz Júnior, José Antônio Picanço; Araújo, Sanderson Corrêa; Campos, Marliane Batista; Marinho, Andrey Moacir do Rosário; Brandão, Geraldo Célio; Vale, Valdicley Vieira; Percário, Sandro; Dolabela, Maria Fâni
This study evaluated the morphological changes caused by fractions and subfractions, obtained from barks of Aspidosperna nitidum, against L. (L.) amazonensis promastigotes. The ethanolic extract (EE) obtained through the maceration of trunk barks was subjected to an acid–base partition, resulting the neutral (FN) and the alkaloid (FA) fractions, and fractionation under refux, yielded hexane (FrHEX), dichloromethane (FrDCL), ethyl acetate (FrACoET), and methanol (FrMEOH) fractions. The FA was fractionated and three subfractions (SF5-6, SF8, and SF9) were obtained and analyzed by HPLC–DAD and 1 H NMR. The antipromastigote activity of all samples was evaluated by MTT, after that, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for the active fractions were performed. Chromatographic analyzes suggest the presence of alkaloids in EE, FN, FA, and FrDCL. The fractionation of FA led to the isolation of the indole alkaloid dihydrocorynantheol (SF8 fractions). The SF5-6, dihydrocorynantheol and SF-9 samples were active against promastigotes, while FrDCL was moderately active. The SEM analysis revealed cell rounding and changes in the fagellum of the parasites. In the TEM analysis, the treated promastigotes showed changes in fagellar pocket and kinetoplast, and presence of lipid inclusions. These results suggest that alkaloids isolated from A. nitidum are promising as leishmanicidal.
Activity of the new triazole derivative albaconazole against Trypanosoma (Schizotrypanum) cruzi in dog hosts.
(2004) Guedes, Paulo Marcos da Matta; Urbina, Julio Alberto; Lana, Marta de; Afonso, Luís Carlos Crocco; Veloso, Vanja Maria; Tafuri, Washington Luiz; Coelho, George Luiz Lins Machado; Chiari, Egler; Bahia, Maria Terezinha
Albaconazole is an experimental triazole derivative with potent and broad-spectrum antifungal activity and a remarkably long half-life in dogs, monkeys, and humans. In the present work, we investigated the in vivo activity of this compound against two strains of the protozoan parasite Trypanosoma (Schizotrypanum) cruzi, the causative agent of Chagas’ disease, using dogs as hosts. The T. cruzi strains used in the study were previously characterized (murine model) as susceptible (strain Berenice-78) and partially resistant (strain Y) to the drugs currently in clinical use, nifurtimox and benznidazole. Our results demonstrated that albaconazole is very effective in suppressing the proliferation of the parasite and preventing the death of infected animals. Furthermore, the parasitological, PCR, serological, and proliferative assay results indicated parasitological cure indices of 25 and 100% among animals inoculated with T. cruzi strain Y when they were treated with albaconazole at 1.5 mg/kg of body weight/day for 60 and 90 days, respectively. On the other hand, although albaconazole given at 1.5 mg/kg/day was very effective in suppressing the proliferation of the parasite in animals infected with the Berenice-78 T. cruzi strain, no parasitological cure was observed among them, even when a longer treatment period (150 doses) was used. In conclusion, our results demonstrate that albaconazole has trypanocidal activity in vivo and is capable of inducing radical parasitological cure, although natural resistance to this compound was also indicated. Furthermore, the compound can be used in long-term treatment schemes (60 to 150 days) with minimal toxicity and thus represents a potentially useful candidate for the treatment of human Chagas’ disease.
Adenosine actions are preserved in corpus cavernosum from obese and type II diabetic db/db mouse.
(2008) Carneiro, Fernando Silva; Vitorino, Fernanda Regina Casagrande Giachini; Lima, Victor Vitorino; Neotzold, Zidonia Nunes; Leite, Romulo; Inscho, Edward W.; Passaglia, Rita de Cassia Aleixo Tostes; Webb, Robert Clinton
Introduction—Erectile dysfunction (ED) in diabetes is associated with autonomic neuropathy and endothelial dysfunction. Whereas the nonadrenergic-noncholinergic (NANC)/neurogenic nitric oxide pathway has received great attention in diabetes-associated ED, few studies have addressed sympathetic overactivity. Aim—To test the hypothesis that adenosine-induced inhibition of adrenergic-mediated contractile responses in mouse corpus cavernosum is impaired in the presence of diabetes. Methods—The db/db (obesity and type II diabetes caused by a leptin receptor mutation) mouse strain was used as a model of obesity and type II diabetes, and standard procedures were performed to evaluate functional cavernosal responses. Main Outcome Measures—Increased cavernosal responses to sympathetic stimulation in db/ db mice are not associated with impaired prejunctional actions of adenosine. Results—Electrical field stimulation (EFS)-, but not phenylephrine (PE)-, induced contractions are enhanced in cavernosal strips from db/db mice in comparison with those from lean littermates. Direct effects of adenosine, 2-chloro-adenosine, A1 receptor agonist C-8031 (N6 cyclopentyladenosine), and sodium nitroprusside are similar between the strips from lean and db/ db mice, whereas relaxant responses to acetylcholine and NANC stimulation are significantly impaired in the cavernosal strips from db/db mice. 5′-Iodotubercidin (adenosine kinase inhibitor) and dipyridamole (inhibitor of adenosine transport), as well as the A1 agonist C-8031, significantly and similarly inhibit contractions induced by stimulation of adrenergic nerves in the cavernosal strips from lean and db/db mice. Conclusions—Results from this study suggest that corpora cavernosa from obese and diabetic db/db mice display altered neural-mediated responses that would favor penile detumescence, i.e., increased contractile response to adrenergic nerve stimulation and decreased relaxant responses upon activation of NANC nerves. However, increased cavernosal responses to adrenergic nerve stimulation are not due to impaired negative modulation of sympathetic neurotransmission by adenosine in this diabetic model.
Adhesion on yeast cell surface as a trapping mechanism of pathogenic bacteria by Saccharomyces probiotics.
(2012) Tiago, Fabiana da Conceição Pereira; Martins, Flaviano dos Santos; Souza, Éricka Lorenna de Sales e; Pimenta, Paulo Filemon Paolucci; Araújo, Helena Rocha Corrêa de; Castro, Ieso de Miranda; Brandão, Rogélio Lopes; Nicoli, Jacques Robert
Recently, much attention has been given to the use of probiotics as an adjuvant for the prevention or treatment of gastrointestinal pathology. The great advantage of therapy with probiotics is that they have few side effects such as selection of resistant bacteria or disturbance of the intestinal microbiota, which occur when antibiotics are used. Adhesion of pathogenic bacteria onto the surface of probiotics instead of onto intestinal receptors could explain part of the probiotic effect. Thus, this study evaluated the adhesion of pathogenic bacteria onto the cell wall of Saccharomyces boulardii and Saccharomyces cerevisiae strains UFMG 905, W303 and BY4741. To understand the mechanism of adhesion of pathogens to yeast, cell-wall mutants of the parental strain of Saccharomyces cerevisiae BY4741 were used because of the difficulty of mutating polyploid yeast, as is the case for Saccharomyces cerevisiae and Saccharomyces boulardii. The tests of adhesion showed that, among 11 enteropathogenic bacteria tested, only Escherichia coli, Salmonella Typhimurium and Salmonella Typhi adhered to the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741. The presence of mannose, and to some extent bile salts, inhibited this adhesion, which was not dependent on yeast viability. Among 44 cell-wall mutants of Saccharomyces cerevisiae BY4741, five lost the ability to fix the bacteria. Electron microscopy showed that the phenomenon of yeast–bacteria adhesion occurred both in vitro and in vivo (in the digestive tract of dixenic mice). In conclusion, some pathogenic bacteria were captured on the surface of Saccharomyces boulardii, Saccharomyces cerevisiae UFMG 905 and Saccharomyces cerevisiae BY4741, thus preventing their adhesion to specific receptors on the intestinal epithelium and their subsequent invasion of the host.
Adsorption of starch, amylose, amylopectin and glucose monomer and their effect on the flotation of hematite and quartz.
(2003) Pavlovic, Suzana; Brandão, Paulo Roberto Gomes
The depressant effect of corn starch, its polysaccharide components (amylose and amylopectin), the monomer glucose and the dimer maltose were studied on hematite and quartz, by means of infrared spectrometry, adsorption isotherms determination and microflotation tests. All the carbohydrates tested have been effective in maintaining hematite hydrophilic, including glucose and maltose; as for quartz, only a flocculation action (mainly by amylopectin) had a mild effect in decreasing its floatability by the amine collector. FTIR studies confirmed that the carbohydrates adsorbed intensively onto hematite and the spectra of the adsorbed polymers and monomer were very similar, even though the non-adsorbed monomer spectrum was markedly different. The common adsorption mechanism indicated is a surface reaction involving the iron ion.
Ageing down-modulates liver inflammatory immune responses to schistosome infection in mice.
(2010) Faria, Elaine Speziali de; Aranha, Claudio Henrique Magalhães; Carvalho, Andréa Teixeira de; Santiago, Andrezza Fernanda; Oliveira, Rafael Pires de; Rezende, Michelle Carvalho de; Carneiro, Cláudia Martins; Corrêa, Deborah Aparecida Negrão; Coelho, Paulo Marcos Zech; Faria, Ana Maria Caetano de
Ageing is associated with several alterations in the immune system. Our aim in this study was to compare the development of immunity to Schistosoma mansoni infection in young versus aged C57Bl ⁄ 6 mice using the liver as the main organ to evaluate pathological alterations and immune responses. In the acute phase, young mice had large liver granulomas with fibrosis and inflammatory cells. Chronic phase in young animals was associated with immunomodulation of granulomas that became reduced in size and cellular infiltrate. On the other hand, aged animals presented granulomas of smaller sizes already in the acute phase. Chronic infection in these mice was followed by no alteration in any of the inflammatory parameters in the liver. In concert with this finding, there was an increase in activated CD4+ T, CD19+ B and NK liver cells in young mice after infection whereas old mice had already higher frequencies of activated B, NK and CD4+ T liver cells and infection does not change these frequencies. After infection, liver production of inflammatory and regulatory cytokines such as IFN-c, IL-4 and IL-10 increased in young but not in old mice that had high levels of IL-4 and IL-10 regardless of their infection status. Our data suggest that the unspecific activation status of the immune system in aged mice impairs inflammatory as well as regulatory immune responses to S. mansoni infection in the liver, where major pathological alterations and immunity are at stage. This poor immune reactivity may have a beneficial impact on disease development.
Agitation during lipoplex formation harmonizes the interaction of siRNA to cationic liposomes.
(2012) Barichello, José Mario; Kizuki, Shinji; Tagami, Tatsuaki; Soares, Luiz Alberto Lira; Ishida, Tatsuhiro; Kikuchi, Hiroshi; Kiwada, Hiroshi
We recently demonstrated that agitation during lipoplex formation (vorLTsiR) improves the gene knockdown effect of siRNA because the resultant decrease in lipoplex size leads to an enhanced uptake by cells. In furthering this line of research, the present study was focused on the interaction of siRNA to cationic liposomes during lipoplex preparation. A fluorescence resonance energy transfer (FRET) study indicated that the application of agitation in the presence of siRNA effectively reorganized positively charged lipids (DC-6-14 and DOPE) in an order that effectively promoted further electrostatic interaction between the negatively charged phosphate backbone of siRNA and the positively charged lipids in the cationic liposome membrane. A circular dichroism (CD) study indicated that the agitation did not bring about a change in the A-form helix of siRNA, therefore the interactions between the lateral anionic groups of siRNA – responsible for the characteristic bands of the A-form helix – and cationic liposomes were effectively promoted. Factorial design coupled with response surface methodology was used to statistically analyze the influence of vortex speed and time and siRNA dose on the in vitro gene knockdown effects of siRNA-lipoplex that were spontaneously formulated (spoLTsiR) along with that formulated under agitation (vorLTsiR). The analysis indicated that vortex speed plays the most important role in enhancing the gene knockdown effect of siRNA among the three variables, although all three are important. It was concluded that the high energy transmitted by applying agitation during lipoplex formation harmonized the interaction of siRNA to positively charged lipids (DC-6-14 and DOPE) in cationic liposomes, resulting in a superior gene knockdown efficacy of vorLTsiR compared to spoLTsiR. Our study suggests that the preparation procedure is one of the critical factors in producing the enhanced gene knockdown effect of siRNA.
Alelopatia de Arctius minus Bernh, (Asteraceae) na germinação e crescimento radicular de sorgo e pepino.
(2008) Belinelo, Valdenir José; Czepak, Márcio Paulo; Vieira Filho, Sidney Augusto; Menezes, Luis Fernando Tavares de; Jamal, Claúdia Masrouah
Os objetivos deste trabalho foram identificar e caracterizar a atividade alelopática de extratos obtidos do vegetal Arctium minus (Hill) Bernh (Asteraceae). Foram avaliados a atividade fitotóxica de extratos orgânicos (1 e 100 mg.L-1) e do extrato aquoso (5,00 e 0,05% m/v), sobre a germinação e crescimento radicular de sementes da monocotiledônea Sorghum bicolor L. (sorgo) e da dicotiledônea Cucumis sativus L. (pepino). Os resultados mostraram a presença de atividade alelopática inibitória variável de acordo com a concentração do extrato e com a planta alvo. A intensidade do efeito inibitório induzido foi maior para o extrato etanólico na concentração 100 mg.L-1 para Sorghum bicolor L. Os resultados também indicaram a existência de potencial de utilização do extrato etanólico de Arctium minus (Hill) Bernh como herbicida natural e abriu perspectivas para a pesquisa da(s) substância(s) de maior atividade aleloquímica.
Algistatic effect of a quinonamethide triterpene on Microcystis novacekii.
(2013) Silva, Fernando César; Guedes, Fernanda Alves de Freitas; Franco, Maione Wittig; Barbosa, Francisco Antônio Rodrigues; Marra, Camila Antunes; Duarte, Lucienir Pains; Silva, Grácia Divina de Fátima; Vieira Filho, Sidney Augusto
Cyanobacteria proliferation represents a problem to water treatment for human consumption supply. Species of the genus Microcystis, commonly found in continental waters, can bloom and produce microcystine and other toxic compounds associated to human and animal poisoning, depending on the nutrient levels present in the water. The use of natural products to control cyanobacteria blooms is promising since they are less harmful to the environment than compounds obtained by organic syntheses. Triterpenes, which are associated with several biological activities, have been isolated from species of the genus Maytenus (Celastraceae), commonly found in Cerrado regions of Brazil. Tingenone is a pentacyclic triterpene that has cytotoxic properties and induces growth inhibition in some microorganisms. In this study, the effects of tingenone isolated from Maytenus gonoclada at distinct concentrations (e.g., 50, 150, 500, 1,500, and 4,500 μg L−1) on the growth rates of Microcystis novacekii was investigated. The algicide activity was verified using M. novacekii cultures growing in ASM1 culture medium at 23 °C and continuous illumination for 96 h. Growth inhibition was monitored by light microscopy and optical density (OD680 nm). The median effective concentration associated to the M. novacekii inhibition growth induced by tingenone was 12.2 μg L−1. The result indicates that tingenone has algicide effect and can be potentially applied in water management for public supply, replacing synthetic algicides.
Amphotericin B-loaded Eudragit RL100 nanoparticles coated with hyaluronic acid for the treatment of vulvovaginal candidiasis.
(2020) Melo, Carolina Mirtes; Cardoso, Jéssica Ferreira; Perasoli, Fernanda Barçante; Oliveira Neto, Ari Soares de; Pinto, Luccas Moreira; Marques, Maria Betânia de Freitas; Mussel, Wagner da Nova; Magalhães, Juliana Teixeira de; Moura, Sandra Aparecida Lima de; Araújo, Marcelo Gonzaga de Freitas; Silva, Gisele Rodrigues da
The treatment of vulvovaginal candidiasis (VVC) is based on oral and vaginal formulations which show limited effectiveness. In this study, amphotericin B-loaded Eudragit RL100 nanoparticles coated with hyaluronic acid (AMP EUD nanoparticles/HA) were developed to overcome the drawbacks of the conventional formulations. AMP EUD nanoparticles/HA were synthesized by nanoprecipitation, formulated by statistical experimental design, and characterized. AMP release from EUD nanoparticles/HA and its antifungal activity in a murine model of VVC were evaluated. Nanoparticles showed 147.6 ± 16.7 nm of diameter, 0.301 ± 0.09 of polydispersity index, - 29.9 ± 3.76 mV of zeta potential, and 87.27 % of encapsulation efficiency. They released about 81 % of AMP in 96 h; and provided the elimination of 100 % of the vaginal fungal burden in 24 h. It was suggested that the AMP EUD nanoparticles/HA penetrated into the vaginal epithelium via CD44 receptors. These AMP EUD nanoparticles/HA represent a non-conventional vaginal formulation to improve the treatment of VVC.
An 8-hydroxyquinoline-containing polymeric micelle system is effective for the treatment of murine tegumentary leishmaniasis.
(2016) Lage, Letícia Martins dos Reis; Barichello, José Mario; Lage, Daniela Pagliara; Mendonça, Débora Vasconcelos Costa; Carvalho, Ana Maria Ravena Severino; Rodrigues, Marcella Rezende; Souza, Daniel Menezes; Roatt, Bruno Mendes; Alves, Ricardo José; Tavares, Carlos Alberto Pereira; Coelho, Eduardo Antônio Ferraz; Duarte, Mariana Costa
An alternative in vitro drug screening test using Leishmania amazonensis transfected with red fluorescent protein.
(2013) Rocha, Marcele Neves; Corrêa, Célia Maria; Melo, Maria Norma; Beverley, Stephen M.; Martins Filho, Olindo Assis; Madureira, Ana Paula; Soares, Rodrigo Pedro Pinto
Fluorescent and colorimetric reporter genes are valuable tools for drug screening models, since microscopy islabor intensive and subject to observer variation. In this work, we propose afluorimetric method for drugscreening using redfluorescent parasites. FluorescentLeishmania amazonensiswere developed aftertransfection with integration plasmids containing either red (RFP) or greenfluorescent protein (GFP)genes. After transfection, wild-type (LaWT) and transfected (LaGFP and LaRFP) parasites were subjected toflow cytometry, macrophage infection, and tests of susceptibility to current antileishmanial agents andpropranolol derivatives previously shown to be active againstTrypanosoma cruzi. Flow cytometry analysisdiscriminated LaWT from LaRFP and LaGFP parasites, without affecting cell size or granulosity. Withmicroscopy, transfection with antibiotic resistant genes was not shown to affect macrophage infectivity andsusceptibility to amphotericin B and propranolol derivatives. Retention offluorescence remained in theintracellular amastigotes in both LaGFP and LaRFP transfectants. However, detection of intracellular RFPparasites was only achieved in thefluorimeter. Murine BALB/c macrophages were infected with LaRFPparasites, exposed to standard (meglumine antimoniate, amphotericin B, Miltefosine, and allopurinol) andtested molecules. Although it was possible to determine IC50values for 4 propranolol derivatives (1, 2b, 3, and4b), all compounds were considered inactive. This study is thefirst to develop afluorimetric drug screeningtest forL. amazonensisRFP. Thefluorimetric test was comparable to microscopy with the advantage of beingfaster and not requiring manual counting.
An antigenic domain within a catalytically active leishmania infantum nucleoside triphosphate diphosphohydrolase (NTPDase 1) is a target of inhibitory antibodies.
(2013) Maia, Ana Carolina Ribeiro Gomes; Porcino, Gabriane Nascimento; Detoni, Michelle de Lima; Emídio, Nayara Braga; Marconato, Danielle Gomes; Pinto, Priscila de Faria; Fessel, Melissa Regina; Reis, Alexandre Barbosa; Juliano Neto, Luiz; Juliano, Maria Aparecida; Marques, Marcos José; Vasconcelos, Eveline Gomes
Weidentified a shared B domainwithin nucleoside triphosphate diphosphohydrolases (NTPDases) of plants and parasites. Now, an NTPDase activity not affected by inhibitors of adenylate kinase and ATPases was detected in Leishmania infantum promastigotes. By non-denaturing gel electrophoresis of detergent-homogenized promastigote preparation, an active band hydrolyzing nucleosides di- and triphosphate was visualized and, following SDS-PAGE and silver staining was identified as a single polypeptide of 50 kDa. By Western blots, it was recognized by immune sera raised against potato apyrase (SA), r-pot B domain (SB), a recombinant polypeptide derived fromthe potato apyrase, and LbB1LJ (SC) or LbB2LJ (SD), synthetic peptides derived fromthe Leishmania NTPDase 1, and by serum samples from dogs with visceral leishmaniasis, identifying the antigenic L. infantum NTPDase 1 and, also, its conserved B domain (r83–122). By immunoprecipitation assays andWestern blots, immune sera SA and SB identified the catalytically active NTPDase 1 in promastigote preparation. In addition, the immune sera SB (44%) and SC or SD (87–99%) inhibited its activity, suggesting a direct effect on the B domain. By ELISA, 37%, 45% or 50% of 38 infected dogs were seropositive for r-pot B domain, LbB1LJ and LbB2LJ, respectively, confirming the B domain antigenicity.
An assessment on epitope prediction methods for protozoa genomes.
(2012) Resende, Daniela de Melo; Rezende, Antonio Mauro; Oliveira, Nesley Jesus Daher de; Batista, Izabella Cristina Andrade; Oliveira, Rodrigo Corrêa de; Reis, Alexandre Barbosa; Ruiz, Jeronimo Conceição
Background: Epitope prediction using computational methods represents one of the most promising approaches to vaccine development. Reduction of time, cost, and the availability of completely sequenced genomes are key points and highly motivating regarding the use of reverse vaccinology. Parasites of genus Leishmania are widely spread and they are the etiologic agents of leishmaniasis. Currently, there is no efficient vaccine against this pathogen and the drug treatment is highly toxic. The lack of sufficiently large datasets of experimentally validated parasites epitopes represents a serious limitation, especially for trypanomatids genomes. In this work we highlight the predictive performances of several algorithms that were evaluated through the development of a MySQL database built with the purpose of: a) evaluating individual algorithms prediction performances and their combination for CD8+ T cell epitopes, B-cell epitopes and subcellular localization by means of AUC (Area Under Curve) performance and a threshold dependent method that employs a confusion matrix; b) integrating data from experimentally validated and in silico predicted epitopes; and c) integrating the subcellular localization predictions and experimental data. NetCTL, NetMHC, BepiPred, BCPred12, and AAP12 algorithms were used for in silico epitope prediction and WoLF PSORT, Sigcleave and TargetP for in silico subcellular localization prediction against trypanosomatid genomes. Results: A database-driven epitope prediction method was developed with built-in functions that were capable of: a) removing experimental data redundancy; b) parsing algorithms predictions and storage experimental validated and predict data; and c) evaluating algorithm performances. Results show that a better performance is achieved when the combined prediction is considered. This is particularly true for B cell epitope predictors, where the combined prediction of AAP12 and BCPred12 reached an AUC value of 0.77. For T CD8+ epitope predictors, the combined prediction of NetCTL and NetMHC reached an AUC value of 0.64. Finally, regarding the subcellular localization prediction, the best performance is achieved when the combined prediction of Sigcleave, TargetP and WoLF PSORT is used. Conclusions: Our study indicates that the combination of B cells epitope predictors is the best tool for predicting epitopes on protozoan parasites proteins. Regarding subcellular localization, the best result was obtained when the three algorithms predictions were combined. The developed pipeline is available upon request to authors.
Analgesic and side effects of intravenous recombinant Phα1β.
(2020) Rigo, Flavia Karine; Rossato, Mateus Fortes; Borges, Vanessa; Silva, Juliana Figueira da; Pereira, Elizete Maria Rita; Ávila, Ricardo Andrez Machado de; Trevisan, Gabriela; Astoni, Duana Carvalho dos Santos; Diniz, Danuza Montijo; Silva, Marco Aurélio Romano; Castro Junior, Célio José de; Cunha, Thiago Mattar; Ferreira, Juliano; Gomez, Marcus Vinicius
Background: Intrathecal injection of voltage-sensitive calcium channel blocker peptide toxins exerts analgesic effect in several animal models of pain. Upon intrathecal administration, recombinant Phα1β exerts the same analgesic effects as the those of the native toxin. However, from a clinical perspective, the intrathecal administration limits the use of anesthetic drugs in patients. Therefore, this study aimed to investigate the possible antinociceptive effect of intravenous recombinant Phα1β in rat models of neuropathic pain, as well as its side effects on motor, cardiac (heart rate and blood pressure), and biochemical parameters. Methods: Male Wistar rats and male Balb-C mice were used in this study. Giotto Biotech® synthesized the recombinant version of Phα1β using Escherichia coli expression. In rats, neuropathic pain was induced by chronic constriction of the sciatic nerve and paclitaxel-induced acute and chronic pain. Mechanical sensitivity was evaluated using von Frey filaments. A radiotelemeter transmitter (TA11PA-C10; Data Sciences, St. Paul, MN, USA) was placed on the left carotid of mice for investigation of cardiovascular side effects. Locomotor activity data were evaluated using the open-field paradigm, and serum CKMB, TGO, TGP, LDH, lactate, creatinine, and urea levels were examined. Results: Intravenous administration of recombinant Phα1β toxin induced analgesia for up to 4 h, with ED50 of 0.02 (0.01-0.03) mg/kg, and reached the maximal effect (Emax = 100% antinociception) at a dose of 0.2 mg/kg. No significant changes were observed in any of the evaluated motor, cardiac or biochemical parameters. Conclusion: Our data suggest that intravenous administration of recombinant Phα1β may be feasible for drug-induced analgesia, without causing any severe side effects.