A high throughput colorimetric assay of beta-1,3-D-glucans by Congo red dye

Mushroom strains contain complex nutritional biomolecules with a wide spectrum of therapeutic and prophylactic properties. Among these compounds, β-d-glucans play an important role in immuno-modulating and anti-tumor activities. The present work involves a novel colorimetric assay method for β-1,3-d-glucans with a triple helix tertiary structure by using Congo red. The specific interaction that occurs between Congo red and β-1,3-d-glucan was detected by bathochromic shift from 488 to 516 nm (> 20 nm) in UV–Vis spectrophotometer. A micro- and high throughput method based on a 96-well microtiter plate was devised which presents several advantages over the published methods since it requires only 1.51 μg of polysaccharides in samples, greater sensitivity, speed, assay of many samples and very cheap. β-d-Glucans of several mushrooms (i.e., Coriolus versicolor, Ganoderma lucidum, Pleurotus ostreatus, Ganoderma carnosum, Hericium erinaceus, Lentinula edodes, Inonotus obliquus, Auricularia auricular, Polyporus umbellatus, Cordyseps sinensis, Agaricus blazei, Poria cocos) were isolated by using a sequence of several extractions with cold and boiling water, acidic and alkaline conditions and quantified by this microtiter plate method. FTIR spectroscopy was used to study the structural features of β-1,3-d-glucans in these mushroom samples as well as the specific interaction of these polysaccharides with Congo red. The effect of NaOH on triple helix conformation of β-1,3-d-glucans was investigated in several mushroom species.

Percepção dos técnicos de anatomia patológica face à perigosidade dos agentes químicos utilizados nos laboratórios de histopatologia

Os agentes químicos são frequentemente manipulados nos Laboratórios de Anatomia Patológica (AP), provocando uma preocupação crescente com a segurança, higiene e a saúde dos técnicos de AP. Não existe conhecimento relativo à percepção que os profissionais evidenciam relativamente à perigosidade das substâncias químicas e que paralelismo esta possui com a real perigosidade, tendo em conta que existem instrumentos internacionais que permitem quantificar o risco associado a cada um dos agentes químicos. O objectivo do trabalho é identificar a percepção dos técnicos de AP relativamente à perigosidade das substâncias químicas utilizadas nos laboratórios de histopatologia dos serviços de AP na região de Lisboa e Vale do Tejo e comparar essa percepção com a perigosidade definida pelos instrumentos internacionais, constituindo, desta forma, um índice de discrepância. Também se procuraram listar os principais sintomas/doenças potencialmente associados à actividade profissional. Para tal, recorreu-se a uma amostra não probabilística, constituída por dezassete técnicos de AP que trabalham em três hospitais na referida região. O instrumento de recolha de dados consistiu num questionário que agrupava questões sobre a temática proposta, incidindo na classificação de substâncias químicas quanto à sua perigosidade para a saúde numa escala de 0 a 5, padecimento ou não de patologias, entre outras. O tratamento estatístico foi realizado em SPSS 12.0. Na generalidade, a discrepância quanto à perigosidade das substâncias químicas é baixa, centrando-se em 1 a 2 e observa-se maior discrepância para as substâncias etanol, violeta de cristal e vermelho do Congo. Os sintomas mais referidos foram cefaleias, irritação dos olhos e das vias respiratórias.

Molecular imaging agents for detection of β-amyloid plaques in Alzheimer’s disease

The formation of amyloid structures is a neuropathological feature that characterizes several neurodegenerative disorders, such as Alzheimer´s and Parkinson´s disease. Up to now, the definitive diagnosis of these diseases can only be accomplished by immunostaining of post mortem brain tissues with dyes such Thioflavin T and congo red. Aiming at early in vivo diagnosis of Alzheimer´s disease (AD), several amyloid-avid radioprobes have been developed for b-amyloid imaging by positron emission tomography (PET) and single-photon emission computed tomography (SPECT). The aim of this paper is to present a perspective of the available amyloid imaging agents, special those that have been selected for clinical trials and are at the different stages of the US Food and Drugs Administration (FDA) approval.

A novel colorimetric assay of beta-D-glucans in basidiomycete strains by alcian blue dye in a 96-well microtiter plate

Basidiomycete strains synthesize several types of beta-D-glucans, which play a major role in the medicinal properties of mushrooms. Therefore, the specific quantification of these beta-D-glucans in mushroom strains is of great biochemical importance. Because published assay methods for these beta-D-glucans present some disadvantages, a novel colorimetric assay method for beta-D-glucan with alcian blue dye was developed. The complex formation was detected by following the decrease in absorbance in the range of 620 nm and by hypsochromic shift from 620 to 606 nm (similar to 14 nm) in UV-Vis spectrophotometer. Analysis of variance was used for optimization of the slope of the calibration curve by using the assay mixture containing 0.017% (w/v) alcian blue in 2% (v/v) acetic acid at pH 3.0. The high-throughput colorimetric assay method on microtiter plates was used for quantification of beta-D-glucans in the range of 0-0.8 mu g, with a slope of 44.15 x 10(-2) and a limit of detection of 0.017 mu g/well. Recovery experiments were carried out by using a sample of Hericium erinaceus, which exhibited a recovery of 95.8% for beta-1,3-D-glucan. The present assay method exhibited a 10-fold higher sensitivity and a 59-fold lower limit of detection compared with the published method with congo red beta-D-glucans of several mushrooms strains were isolated from fruiting bodies and mycelia, and they were quantified by this assay method. This assay method is fast, specific, simple, and it can be used to quantify beta-D-glucans from other biological sources. (C) 2015 American Institute of Chemical Engineers