Analysis of the genetic variability of PvMSP-3α among Plasmodium vivax in Brazilian field isolates

Reliable molecular markers are essential for a better understanding of the molecular epidemiology of Plasmodium vivax, which is a neglected human malaria parasite. The aim of this study was to analyze the genetic diversity of P. vivax isolates from the Brazilian Amazon using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the highly polymorphic merozoite surface protein-3alpha (PvMSP-3α) gene. To accomplish this, 60 isolates of P. vivax from different endemic areas in the Brazilian Amazon were collected. The PvMSP-3α gene was amplified by nested-PCR. Three major types of the PvMSP-3α locus were detected at different frequencies: type A (68%), B (15%) and C (17%). A single sample showed two PCR fragments, which corresponded to infection with types A and C. PCR-RFLP analysis using the HhaI restriction enzyme for 52 isolates clearly identified 11 haplotypes, eight of which were from type A, two from type B and only one from type C. Seven other isolates did not show a clear pattern using PCR-RFLP. This result might be due to multiple clone infections. This study showed a high diversity of the PvMSP-3α gene among P. vivax isolates from the Brazilian Amazon, but also indicated that the detection performance of PCR-RFLP of the PvMSP-3α gene may not be sufficient to detect multiple clone infections.

Production of TNF-α, nitric oxide and hydrogen peroxide by macrophages from mice with paracoccidioidomycosis that were fed a linseed oil-enriched diet

Omega-3 polyunsaturated fatty acids (n-3 PUFA) can modulate the immune system and their primary effect is on macrophage function. Paracoccidioidomycosis (PCM) is an endemic systemic mycosis in Latin America that is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb). Macrophages are the main defence against this pathogen and have microbicidal activity that is dependent on interferon-Γ and tumour necrosis factor (TNF)-α. These cytokines stimulate the synthesis of nitric oxide (NO) and hydrogen peroxide (H2O2), leading to the death of the fungus. To study the effect of n-3 PUFA on the host immune response during experimental PCM, macrophages that were obtained from animals infected with Pb18 and fed a diet enriched by linseed (LIN) oil were cultured and challenged with the fungus in vitro. The macrophage function was analysed based on the concentrations of TNF-α, NO and H2O2. LIN oil seems to influence the production of TNF-α during the development of disease. A diet enriched with LIN oil influences the microbicidal activity of the macrophages by inducing the production of cytokines and metabolites such as NO and H2O2, predominantly in the chronic phase of infection.

Utilização de α,α-Diclorociclobutanonas em Síntese de Produtos Naturais

The preparation and chemical potentiality of a,a-dichlorocyclobutanones as useful intermediates in the total synthesis of natural products are reviewed. Some aspects related to the recent advances reported in the literature about the mechanism of [2+2] cycloaddition reaction between dichloroketene and olefins are also presented.

Obtenção e caracterização de α-quitina e quitosanas de cascas de Macrobrachium rosembergii

The shells of Macrobrachium rosenbergii were submitted to deproteinization (Dp) and demineralization (Dm) aiming the extraction of α-chitin. The different parts of the shells were processed independently by carrying out sequence 1 (Dp/Dm) and sequence 2 (Dm/Dp). Both sequences allowed the extraction of chitins with low contents of calcium and magnesium, regardless of the part being processed. The sequence 1 lead to higher extraction yields while sequence 2 resulted in lower contents of inorganic compounds. Extensively deacetylated chitosans (GA<10%) of medium molecular weight (0,9 x 10(5) < Mv < 2 x 10(5) g/mol) resulted from the deacetylation of chitin.

Síntese e avaliação da atividade fitotóxica de derivados da α-Santonina

Mixtures of α-Santonin and various solvents were irradiated by either high or low pressure mercury lamps. The photochemical reactions afforded lumisantonin (11) (76% in acetonitrile), (3S,3aS,9bS)-3,6,6-trimethyl-3,3a,4,5-tetrahydronafto[1,2-b]furan-2,7(6H,9bH)dione (12) (100% in acetonitrile), 10α-acetoxy-3-oxo-1,7αH,6,11βH-guaia-4-en-6,12-olide (8) (26% in acetic acid), 10α-hydroxy-3-oxo-1,7αH,6,11βH-guaia-4-en-6,12-olide (10) (32%) and (E)-3-((3S,3aS,7aS)-3-methyl-2-oxo-6-(propan-2-ylidene)hexahydrobenzofuran-7-(7aH)-ylidene)propanoic acid (9) (44%) (in water/ acetic acid 1:1, v/v). Lactone 12 was also prepared by irradiation of lumisantonin in diethyl ether. Lactones 8 and 10 were converted, respectively, into the 10α-acetoxy-3β-hydroxy-1,7αH,6,11βH-guaia-4-en-6,12-olide (13) (87%) and 3β,10α-dihydroxy-1,7αH,6,11βH-guaia-4-en-6,12-olide (14) (75%) by sodium borohydride reduction. The effects of the compounds on the development of radicle of Sorghum bicolor and Cucumis sativus were evaluated.

Influência de diferentes sistemas de solvente água-etanol sobre as propriedades físico-químicas e espectroscópicas dos compostos macrocíclicos feofitina e clorofila α

This work focus on the influence of solvent on the photophysical properties of chlorophyll α and pheophytin. Both compounds are related to the photosynthesis process and are considered prototypes of photosensitizers in Photodynamic Therapy. Fluorescence measurements were developed using water/ethanol mixtures at different compositions, since both solvents could be employed in biological applications. The spectroscopic properties of these compounds undergo profound changes depending on water content in the ethanol due to auto-aggregation processes. The major hydrophobicity and the lower dielectric constant of ethanol when compared with water precluded significantly the auto-aggregation process of these compounds.

Aplicação de α-oxoceteno ditiocetais em síntese orgânica

The synthesis and reactivity of α-oxoketenes dithioacetals (S,S-acetals), general structure [(R¹C=OC(R²)=C(SR³)(SR4)], are reported. We also showed the application of S,S acetals as synthons for efficient synthesis of isoxazoles, pyrazoles, indazoles, thiophenes, dithiol thiones, pyridines, pyrimidines and other heterocycles. This work aims to review the importance of α-oxoketenes dithioacetals in organic chemistry during the past few years.

A green synthesis of α,β-unsaturated carbonyl compounds from glyceraldehyde acetonide

The catalytic behavior of Cs-exchanged and Cs-impregnated zeolites (X and Y) was studied using the Knoevenagel condensation between glyceraldehyde acetonide and ethyl acetoacetate in order to produce the corresponding α,β-unsaturated carbonyl compound that is an important intermediate for fine chemicals. The influence of reaction temperature, type of zeolite, and basicity of the sites on the catalytic behavior of the samples was evaluated. All zeolites were active for the studied reaction. The formation of the main condensation product was favored at lower reaction temperatures. Products of further condensations were also observed especially for samples that were only dried before catalytic test.

Separação semipreparativa de α e β-amirina por cromatografia líquida de alta eficiência

The resin obtained from species of the genus Protium (Burseraceae) is formed mostly of pentacyclic triterpenes: α-amyrin and β-amyrin. The separation and purification of these triterpenes were optimized in three steps.

Remoção dos hormônios 17β-estradiol e 17α-etinilestradiol de soluções aquosas empregando turfa decomposta como material adsorvente

This paper describes the adsorption of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solution by decomposed peat. The peat presented a good adsorption process, close to 76.2% for E2 removal and approximately 55.0% for EE2. Moreover, the results indicated a probable multi-layered process. Adsorption isotherms were well fitted by Freundlich model. The data were evaluated considering the pseudo-first-order and pseudo-second-order approaches, being the second more significant mechanism in the rate-controlling step. Thermodynamic data revealed that hormones adsorption onto peat is spontaneous under the employed experimental conditions. The results confirmed the potential of this adsorbent to be employed for effluents treatment.

Phaeophytins from Thyrsacanthus ramosissimus Moric. with inhibitory activity on human dna topoisomerase II-α

Our study reports the extraction and isolation of a new phaeophytin derivative 15¹-hydroxy-(15¹-S)-porphyrinolactone, designated anamariaine (1) herein, isolated from the chloroform fraction of aerial parts of Thyrsacanthus ramosissimus Moric. along with the known 15¹-ethoxy-(15¹-S)-porphyrinolactone (2). These compounds were identified by usual spectroscopic methods. Both compounds were subjected to in vitro (inhibitory activity) tests by means of supercoiled DNA relaxation techniques and were shown to display inhibitory activity against human DNA topoisomerase II-α at 50 µM. Interconversion of these two pigments under the mild conditions of the isolation techniques should be highly unlikely but cannot be entirely ruled out.

Neolignans from Licaria chrysophylla and Licaria aurea with DNA topoisomerase II-α inhibitory activity

Seven natural neolignans isolated from Licaria chrysophylla and Licaria aurea along with five semisynthetic derivatives were tested for their inhibitory action on DNA-topoisomerase by relaxation assays on pBR322 plasmid DNA. All compounds tested showed strong inhibition at a concentration of 100 µM, while none showed activity between 5 and 70 µM. These results indicate that no obvious correlation can be derived between the structure of these compounds and their inhibitory effect on the DNA relaxation activity of topoisomerase II. This is the first report on DNA topoisomerase II inhibitors from Licaria chrysophylla and Licaria aurea leading to the identification of lignoids as topoisomerase II-α inhibitors.

Fármacos multifuncionais: monoamina oxidase e α-sinucleína como alvos terapêuticos na doença de Parkinson

Parkinson's disease (PD) is a neurodegenerative disorder associated to selective degeneration of dopaminergic neurons caused by an intricate relationship among dopamine metabolism, oxidative stress and α-synuclein fibrillation. Most therapies for PD have focused on dopamine replacement through the use of both monoamine oxidase inhibitors (MAOIs) and dopamine precursor L-dopa. Interestingly, certain MAOIs have a broad spectrum of action including anti-fibrillogenic properties in α-synuclein aggregation. Herein we revisit the chemical properties of MAOIs and their action on important targets associated with PD, notably α-synuclein fibrillation and dopamine metabolism, discussing the strategies associated with the development of multi-target drugs for neurodegenerative diseases.

Câmara de volatilização: uma alternativa para avaliação da eficiência de amostragem de α- e β-endossulfam em fase gasosa

The efficiency of XAD®-2 resin in sampling the pesticides α and β-endosulfan from air contaminated in the laboratory was evaluated. Sampling efficiency ranged from 87 to 108% for α-endosulfan and from 71 to 84% for β-endosulfan with relative standard deviation lower than 19%. The pesticides were not detected in the second section of the cartridge showing the good retention capacity of XAD®-2 for these analytes. Method quantification limits were 0.32 and 0.34 µg m-3 for α and β-endosulfan, respectively. These results suggest that the proposed method may be useful for evaluating occupational exposure to these compounds.

DFT study on low molecular weight α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide bridged derivatives

The equilibrium geometries of α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene (DBDT) and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide (DBDTO) were studied at the DFT level of theory with a standard 6-311G* basis set. The molecular structures of the DBDT series were more planar than the corresponding DBDTO series, as revealed by dihedral angles. The UV-visible absorption calculated at TD-DFT/6-311G* showed two absorption peaks for all the molecules except C=S and C=O bridged molecules. In DBDTOs, C=S and C=O bridged molecules showed three and four absorption peaks, respectively. The DBDTOs had lower band gaps and longer wavelengths compared to the corresponding DBDTs.