Evaluation of the antigenotoxicity of polysaccharides and beta-glucans from Agaricus blazei, a model study with the single cell gel electrophoresis/Hep G2 assay

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genotoxicity assessment of water soluble fractions of biodiesel and its diesel blends using the Salmonella assay and the in vitro MicroFlow (R) kit (Litron) assay

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of chemopreventive activity of glutamine by the comet and the micronucleus assay in mice's peripheral blood

This research has evaluated the effects of enteral supplementation of glutamine in clastogens and genotoxic damages caused by the acute administration of cisplatin. For this. it was utilized Swiss mice distributed in eight experimental groups: control, cisplatin, glutamine, in three different doses and the combination of these with cisplatin. The results show that the glutamine was present in neither genotoxic nor mutagenic activity. When in association with glutamine and cisplatin, in simultaneous treatment, it was verified the frequency decreased of micronuclei and comets. The damage reduction percentages to the micronucleus ranged from 95.4 to 91.8% after 24 h of administration of these compounds and 76.7 to 56.8% after 48 h. In the same time the damage reduction percentages to the comet test ranged from 117.0 to 115.0%. The results suggest that glutamine is capable of preventing genotoxic and mutagenic damage according to the experimental design proposed. (C) 2009 Elsevier B.V. All rights reserved.

Colorimetric enzymatic assay of L-malic acid using dehydrogenase from baker's yeast

A colorimetric method has been developed and optimized to measure L-malic acid in samples of fruit juices and wine. This method is based on oxidation of the analyte, catalyzed by malate dehydrogenase (MDH) from dry baker's yeast, and in combination with the reduction of a tetrazolium salt (MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). In the present study, the method exhibited sensitivity in the range of 500-4000 mu M of L-malic acid in the reaction cuvette, with the lower detection limit of 6.7-10(-2) g/L, the upper limit of 53.6.10(-2) g/L and a maximum standard deviation of only 2.5 % for the analyzed samples. The MDH activity from baker's yeast was also optimized, the enzyme showed a high stability at pH=8.0-9.0 and the activity was maintained completely at temperatures up to 40 degrees C for 1 hour. The results show that the colorimetric method using enzymatic preparations from dry baker's yeast is a simple and low-cost method with possibility of wide application.

Development of a rapid one-step immunochromatographic assay for HCV core antigen detection

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Differential Toxicity of Disperse Red 1 and Disperse Red 13 in the Ames Test, HepG2 Cytotoxicity Assay, and Daphnia Acute Toxicity Test

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Study of Salmonella typhimurium mutagenicity assay of (E)-piplartine by the Ames test

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Detection of Cryptosporidium parvum oocysts in calf fecal samples by direct immunofluorescence assay

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Development of an enzyme-linked immunosorbent assay for detection of IgM antibodies to Babesia bigemina in cattle

A crude antigenic preparation of Babesia bigemina was used to develop an ELISA for the detection of IgM antibodies. Optimal dilutions of the antigen, using positive and negative reference sera, were determined by checkerboard titrations. Negative sera from cattle imported from tick-free areas, serum samples collected from infected B. bigemina cattle were used to validate the test. The specificity was 94% and sensitivity of the Elisa 87.5%. Sera from 385 cattle deriving from areas free from tick-borne diseases, which were submitted to a preimmunization process, were screened by this technique. The Elisa detected seroconversion on the 14th day post-inoculation in animals either infested with Boophilus microplus ticks (infected with B. bigemina), or inoculated with B. bigemina infected blood. Antibody titers decreased after day 33; however, all animals remained positive until the end of the experiment (124 days). The ELISA described may prove to be an appropriate serological test for the detection of IgM antibodies against B. bigemina.

Determinação de carbaril utilizando testes ELISA (Enzyme-linked immunosorbent assay) e CLAE com detecção por arranjo de diodos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Teste imunoenzimático (enzyme-linked immunosorbent assay) para diagnóstico da cisitcercose bovina e estudo da cinética de produção de anticorpos contra-Cysticercus bovis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evolution of subpatent parasitaemia in Trypanosoma cruzi chronically infected mice with the help of a cyclophosphamide amplification transfer assay

Avaliamos o potencial do ensaio clássico de subinoculação, modificado pelo tratamento com ciclofosfamida dos animais receptores, na detecção de parasitemias ocultas em camundongos com in-fecção crônica pelo Trypanosoma cruzi. O ensaio, além de simples, mostrou ter uma alta sensibilidade; assim, utilizando-se parasitas da fase aguda, o tratamento com ciclofosfamida revelou parasitemias em 53,8% dos animais infectados com um tripanosoma da cepa y, e em 20% dos animais infectados com um tripanosoma da cepa CL. O tratamento com ciclofosfamida aumentou a sensibilidade do ensaio de subinoculação nas infecções pela cepa CL, e resultou em igual sensibilidade quando utilizada a cepa Y. Nos camundongos de fase crônica, obtidos a partir de diversos esquemas de imunoprofilaxia (BCG, soro de camundongo imune) ou quimioterapia, o ensaio revelou parasitemias ocultas em 99% dos animais. Auxiliados pelo método da subinoculação-ciclofosfamida estudamos no espaço de um ano a evolução das parasitemias ocultas em um grupo de camundongos infectados que sobreviveram à fase aguda pelo tratamento com Benzonidazol. O ensaio revelou parasitemias ocultas em 100% dos animais. Entretanto, padrões contínuos e discontinuos de positividade puderam ser detectados.

Genotoxicity and mutagenicity of water contaminated with tannery effluents, as evaluated by the micronucleus test and comet assay using the fish Oreochromis niloticus and chromosome aberrations in onion root-tips

Cytotoxicity of metals is important because some metals are potential mutagens able to induce tumors in humans and experimental animals. Chromium can damage DNA in several ways, including DNA double strand breaks (DSBs) which generate chromosomal aberrations, micronucleus formation, sister chromatid exchange, formation of DNA adducts and alterations in DNA replication and transcription. In our study, water samples from three sites in the Córrego dos Bagres stream in the Franca municipality of the Brazilian state of São Paulo were subjected to the comet assay and micronucleus test using erythrocytes from the fish Oreochromis niloticus. Nuclear abnormalities of the erythrocytes included blebbed, notched and lobed nuclei, probably due to genotoxic chromium compounds. The greatest comet assay damage occurred with water from a chromium-containing tannery effluent discharge site, supporting the hypothesis that chromium residues can be genotoxic. The mutagenicity of the water samples was assessed using the onion root-tip cell assay, the most frequent chromosomal abnormalities observed being: c-metaphases, stick chromosome, chromosome breaks and losses, bridged anaphases, multipolar anaphases, and micronucleated and binucleated cells. Onion root-tip cell mutagenicity was highest for water samples containing the highest levels of chromium.

Atrazine interaction with tropical humic substances by Enzyme Linked Immunosorbent Assay

Enzyme-Linked Immunosorbent Assay (ELISA) has been evaluated by analyzing rich-humic water samples from tropical rivers. The samples were spiked with atrazine at ppb level Different pHs (4 to 9) and humic concentrations (2.5 to 40 mg L-1) were investigated. The assay performance showed a strong dependence on the pH values and amount of humic matter at low atrazine concentration. From all the conditions studied the low pH (pH 4) and high humic substances concentrations (40 mg L-1) showed the greatest influence. The IC50 value to control sample (no humic) diminished from 0.28 nmol L-1 to 0.64 nmol L-1 to humic acid solution. This effect is specially noted for the humic acid fractions, since fulvic acid fractions showed no significant change on the immunoassay results. Additionally, it has been demonstrated that at basic pH the matrix effect produced by the natural Brazilian water sample containing humic substances even at 40 mg L-1 disappears. Therefore, the ELISA method used to determine atrazine, can be employed to determine this pesticide in water samples containing humic substances without prior preparation.