Polymorphism in the IL-1ß promoter is associated with IgG antibody response to circumsporozoite protein repeats of Plasmodium vivax.

BACKGROUND: It is well established that infection by Plasmodium vivax is a result of host-parasite interactions. In the present study, association with the IL1/IL2 cytokine profiles, anticircumsporozoite protein antibody levels and parasitic loads was evaluated in individuals naturally infected with P. vivax in an endemic area of the Brazilian Amazon. METHODS: Molecular diagnosis of P. vivax and variants was performed using the PCR-RFLP method and IL1B -511C>T, IL2 -330T>G and IL2+114T>G polymorphisms were identified using PCR-RFLP and allele-specific PCR. IL-1ß and IL-2 cytokine levels were detected by flow cytometry and circumsporozoite protein (CSP) antibodies were measured by ELISA. RESULTS: Three variants of P. vivax CSP were identified and VK247 was found to be the most frequent. However, the prevalence and magnitude of IgG antibodies were higher for the VK210 variant. Furthermore, the antibody response to the CSP variants was not associated with the presence of the variant in the infection. Significant differences were observed between the single nucleotide polymorphism (SNP) -511T>C in the IL1B gene and levels of antibodies to the VK247 and P. vivax-like variants, but there were no associations between SNPs in IL1 and IL2 genes and their plasma products. CONCLUSIONS: Individuals with the rs16944 CC genotype in the IL1ß gene have higher antibody levels to the CSP of P. vivax of VK247 and P. vivax-like variants.

Impact of population admixture on the distribution of immune response co-stimulatory genes polymorphisms in a Brazilian population.

Co-stimulatory molecules are essential in the orchestration of immune response and polymorphisms in their genes are associated with various diseases. However, in the case of variable allele frequencies among continental populations, this variation can lead to biases in genetic studies conducted in admixed populations such as those from Brazil. The aim of this study was to evaluate the influence of genomic ancestry on distributions of co-stimulatory genes polymorphisms in an admixed Brazilian population. A total of 273 individuals from the north of Brazil participated in this study. Nine single nucleotide polymorphisms in 7 genes (CD28, CTLA4, ICOS, CD86, CD40, CD40L and BLYS) were determined by polymerase chain reaction-restriction fragment length polymorphism. We also investigated 48 insertion/deletion ancestry markers to characterize individual African, European and Amerindian ancestry proportions in the samples. The analysis showed that the main contribution was European (43.9%) but also a significant contribution of African (31.6%) and Amerindian (24.5%) ancestry. ICOS, CD40L and CD86 polymorphisms were associated with genomic ancestry. However there were no significant differences in the proportions of ancestry for the other SNPs and haplotypes studied. Our findings reinforce the need to apply AIMs in genetic association studies involving these polymorphisms in the Brazilian population.

Humoral immune responses against the malaria vaccine candidate antigen Plasmodium vivax AMA-1 and IL-4 gene polymorphisms in individuals living in an endemic area of the Brazilian Amazon.

BACKGROUND: Several studies have recently demonstrated that the immune responses against malaria is governed by different factors, including the genetic components of the host. The IL-4 gene appears to be a strong candidate factor because of its role in the regulation of the Th2 response. The present study investigated the role of IL-4 polymorphisms in the development of IgG antibodies against PvAMA-1 and the IL-4 levels in individuals infected with Plasmodium vivax in a malaria endemic area in the Brazilian Amazon. METHODS: The study sample included 83 patients who were diagnosed with P. vivax infection using thick smear and confirmed by nested-PCR. The IL-4 -590C>T and IL-4 -33C>T polymorphisms were genotyped by PCR-RFLP, and the intron 3 VNTR was genotyped by PCR. A standardised ELISA protocol was used to measure the total IgG against PvAMA-1. The cytokine/chemokine levels were measured using a Milliplex multiplex assay (Millipore). All of the subjects were genotyped with 48 ancestry informative markers to determine the proportions of African, European and Amerindian ancestry using STRUCTURE software. RESULTS: Of the 83 patients, 60 (73%) produced IgG antibodies against PvAMA-1. A significant decrease in the percentage of respondents was observed among the primo-infected individuals. No significant differences were observed in the frequencies of genotypes and haplotypes among individuals who were positive or negative for IgG antibodies against PvAMA-1. Furthermore, no significant correlation was observed between the IL-4 polymorphisms, antibody levels, IL-4 levels, and parasitemia. CONCLUSIONS: This study indicated that the polymorphisms identified in the IL-4 gene are not likely to play a role in the regulation of the antibody response against PvAMA-1 and IL-4 production in vivax malaria.

Determinação de polifenóis (taninos) em produtos alimentícios (chás) usando biossensor de Polifenol oxidase, obtida de extrato bruto da casca de banana nanica (Musa acuminata) e caracterização desse biossensor / Determination of polyphenols (tanines) in foods products (teas) using a biosensor of Polyphenol oxidase, obtained of crude extract of banana nanica peel (Musa acuminata) and characterization this biosensor

Introdução - Extrato bruto da casca de banana nanica (Musa acuminata); melhor fonte de enzima Polifenol oxidase (PFO) [EC.1.14.18.1] foi estudado como material biocatalítico para a oxidação aeróbica de substratos fenólicos. Materiais e Métodos - O extrato bruto de PFO foi obtido como em Perone et al.14 (2000). A atividade da enzima PFO e proteína total foram determinadas nesse extrato. Foi construído um biossensor desse extrato bruto da casca de banana nanica com 75 unidades de PFO, imobilizada com reagente glutaraldeído. Resultados - Esse biossensor, sensível a polifenóis, foi caracterizado e apresentou pH ótimo de imobilização da enzima igual a 6,5 e sensibilidade acentuada para o substrato catecol. Também foi utilizado no estudo da determinação da concentração de taninos em amostras de diversos tipos de chás. Conclusões - Foi verificado que a porcentagem de erro comparando com o método espectrofotométrico apresentou valores menores que 1,0% estando, portanto, de acordo com o procedimento padrão oficial. Comparando os resultados obtidos com esse biossensor e o de extrato bruto da polpa de banana nanica observamos, melhor tempo de armazenamento das membranas com a casca do que com a polpa, e uma diminuição significativa na quantidade de extrato imobilizado. Assim, conclui-se que o extrato de PFO da casca é melhor fonte de enzima do que a polpa e, portanto, será usado na construção dobiossensor. A vantagem do método amperométrico apresentado é possuir baixo custo, rapidez nas determinações e boa sensibilidade comparado com métodos cromatográficos.

Introduction - Crude extract of banana nanica (Musa acuminata); the best source of enzyme Poliphenol oxidase (PPO) [EC.1.14.18.1] was studied as biocatalytic material to the aerobic oxidation of phenolics substrates. Materials and Methods - The crude extract of I was done the same as at Perone et al.14 (2000). The activity from the enzyme PPO and total protein were determined in this extract. It has been built a biosensor of this crude extract from the peel of stunded banana with 75unities of PPO immobilized with glutaraldeyde reagent. Results - This biosensor, sensitive to poliphenol, was characterized and presented immobilizing optimium pH of the enzyme equal to 6.5and acute sensibility to its catechol substrate. It was also used at the study of the determination of tanines concentration in samples of many kinds of tea. Conclusions - It was verified that percentage of error comparing with the spectrophotometric method, has presented lower than 1,0% values according to the standard methods. Comparing the results obtained with this biosensor and the crude extract of the pulp of banana nanica, it was observed the better stock time of the membranes with the peel than with the pulp, and significative diminishing of the amount of immobilized extract. So, we conclude that the extract of PPO from the peel is better source of enzyme than the pulp and it will be used at the construction of the biosensor. The advantage of the amperometrics methods presented is to obtain low cost, fast determination and good sensibility compared to cromatographics methods.

Caracterização cinética da enzima polifenol oxidase, usando extrato bruto da casca de banana nanica (Musa acuminata) / Kinetic characterization of enzyme polyphenol oxidase, utilizing crude of extract of pell of stunded banana (Musa acuminata)

Introdução - Extrato bruto da casca de banana nanica (Musa acuminata); melhor fonte de enzima polifenol oxidase (PFO) [EC.1.14.18.1] foi estudado como material biocatalítico para a oxidação aeróbica de substratos fenólicos. Material e Métodos - Foi estudada a extração da PFO dessa fonte. A atividade da enzima PFO e proteína total foram determinadas nesse extrato. O estudo da quantidade e do tempo de contato do polímero SB-100 com esse extrato foi realizado. A caracterização cinética da PFO foi determinada com temperatura ótima, estabilidade ao calor, pH ótimo de atividade e de estabilidade. Os valores obtidos foram comparados com a PFO da polpa de banana nanica. Resultados - Os resultados mostraram que a quantidade de polímero SB-100 foi maior usando o extrato da casca de banana nanica do que para a polpa, mas o tempo de contato não houve alteração. O pH de atividade (pH 6,0), de estabilidade (pH 6,5) e a temperatura ótima (30°C), não apresentaram variações comparando os dois extratos utilizados. Conclusões - Verificou-se, portanto que o uso do extrato bruto da casca de banana nanica apresentou maior atividade enzimática de PFO do que para a polpa da fruta; enquanto a caracterização cinética praticamente não variou nos dois extratos. O que se pode concluir é que, para a construção do biossensor a casca da banana é melhor que a polpa por apresentar maior atividade da enzima. A seguir, um biossensor será construído, para detecção de fenólicos e os resultados serão comparados com os da polpa.

Introduction - Crude extract of the pell of stunded banana (Musa acuminata); the best source enzyme polyphenol oxidase (PPO) [EC.1.14.18.1] was studied as material biocatalitic for the aerobic phenolic substratum oxidation. Material and Methods - The extraction of the PPO of this source was studied. The activity of enzyme PPO and total protein had been determined in this extract. The study of the amount and the contact time of polymer SB-100 with this extract was done. The kinetic characterization of the PPO was determined with great temperature, stability to the heat, great pH of activity and stability. The gotten values had been compared with the PPO of the pulp of stunded banana. Results - The results had shown that the amount of polymer SB-100 was bigger used in the extract of the pell of stunded banana than the pulp, but the contact time did not have any alteration. The pH of activity (pH 6,0), of stability (pH 6,5) and the great temperature (30°C), had not presented variations comparing the two used extracts. Conclusions - It was verified, therefore that the use of the crude extract of the pell of stunded banana presented greater enzimatic activity of PPO than in the pulp of fruit; while the kinetic characterization practically did not vary in two extracts. We can conclude that for the construction of the biosensor the pell of the banana is better than the pulp for presenting greater activity of the enzyme. Next, a biosensor will be constructed, for detection of phenolics and the results will be compared with ones the pulp.