Detection of antibodies directed to the N-terminal region of GAD is dependent on assay format and contributes to differences in the specificity of GAD autoantibody assays for type 1 diabetes

Autoantibodies to glutamate decarboxylase (GADA) are sensitive markers of islet autoimmunity and type 1 diabetes. They form the basis of robust prediction models and are widely used for recruitment of subjects at high risk of type 1 diabetes to prevention trials. However GADA are also found in many individuals at low risk of diabetes progression. To identify the sources of diabetes irrelevant GADA reactivity therefore, we analyzed data from the 2009 and 2010 Diabetes Autoantibody Standardization Program GADA workshop and found that binding of healthy control sera varied according to assay type. Characterization of control sera found positive by radiobinding assay, but negative by ELISA showed that many of these sera reacted to epitopes in the N-terminal region of the molecule. This finding prompted development of an N-terminally truncated GAD65 radiolabel, (35)S-GAD65(96-585), which improved the performance of most GADA radiobinding assays (RBAs) participating in an Islet Autoantibody Standardization Program GADA substudy. These detailed workshop comparisons have identified a source of disease-irrelevant signals in GADA RBAs and suggest that N-terminally truncated GAD labels will enable more specific measurement of GADA in type 1 diabetes

Alterações na ultra-estrutura de genótipos de soja em resposta ao fornecimento de manganês em solução nutritiva

The deleterious effects of Mn stress on many species have been studied, mainly concerning biochemical, physiological and growth parameters of plants. However, there are few studies relating the anatomical and ultrastructural changes in response to manganese (Mn) nutritional disorders, This study examined the leaf ultrastructure of Mn-inefficient (IAC-15, Santa Rosa) and Mn-efficient (IAC-Foscarin 31) soybean (Glycine max L.) genotypes in response to three rates of Mn (0.5, 2 and 200 µmol L-1) in the nutrient solution. Symptoms of Mn deficiency developed 12 days after transplanting in IAC-15 and Santa Rosa, followed by IAC-Foscarin 31 on the 15th day. Only IAC-15 and Santa Rosa leaves showed symptoms of Mn toxicity. The Mn concentration in leaves ranged from 8.6 (deficiency) to 886.3 mg kg-1 d.w. (toxicity). There were no changes either in stomata length or stomata number per unit of leaf surface. Cytoplasm disorganization was observed in IAC-15 under Mn-excess. In this case, the cytoplasm was amorphous, densely stained and extensively disorganized, with increased vacuolation. Mn effects were not found in mitochondria and nucleus in any of the genotypes tested. Under all Mn concentrations, many lipid globules were observed in the IAC15 chloroplasts. There was an increase in the number of plastids as well as in the size of starch grains within IAC-Foscarin 31 chloroplasts as Mn concentration in the nutrient solution increased. Genotypes had marked differences in the ultrastructure organization, mainly in leaf chloroplasts grown under conditions of both Mn deficiency and toxicity (the most sensitive genotype was IAC-15).Os efeitos negativos provocados tanto pela deficiência quanto pela toxidez de manganês (Mn) no desenvolvimento das plantas têm sido avaliados, considerando-se os aspectos bioquímicos e produtivos da parte aérea, particularmente, onde os sintomas visuais são manifestados. Entretanto, há poucas informações na literatura abordando as alterações anatômicas e de ultra-estrutura, em relação ao suprimento de Mn. Os objetivos do presente estudo foram avaliar os efeitos do fornecimento de três doses de Mn (0,5; 2 e 200 µmol L-1), em solução nutritiva, nas ultra-estruturas de folhas de cultivares de soja Glycine max (L.): Santa Rosa, IAC-15 e IAC-Foscarin 31, contrastantes quanto à aquisição e ao uso do Mn. Os sintomas visuais de deficiência foram observados primeiramente em Santa Rosa e IAC-15 (ineficientes), os únicos a exibirem sintomas de toxidez. As concentrações de Mn nas folhas com sintomas variaram de 8,6 (deficiência) a 886,3 mg kg-1 (toxidez). Não houve alterações no comprimento e no número de estômatos nos limbos foliares. Em condição de toxidez, constatou-se no IAC-15, citoplasma desorganizado, vacuolado em excesso e denso evidenciando alterações nas membranas dos tilacóides. Não ocorreram alterações ultra-estruturais nas mitocôndrias e no núcleo das células dos três genótipos. Constatou-se presença de glóbulos de lipídios nos cloroplastos do cultivar IAC-15, em todas as condições de fornecimento de Mn. Houve aumento no número de plastídeos e grãos de amido, bem como no tamanho destes no IAC-Foscarin 31 com o suprimento de Mn. Os genótipos, tanto na condição de deficiência quanto de excesso, exibiram distintos graus de organização das ultraestruturas, notadamente, os cloroplastos. O IAC-15 exibiu maiores alterações das ultra-estruturas em função das desordens nutricionais em manganês

The molecular characterisation of type IIA calcium-ATPases in Arabidopsis thaliana

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN031324 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Ca2+ pumps and Ca2+ antiporters in plant development

Calcium (Ca2+) efflux transporters remove Ca2+ from the cytosol of the cell either by transporting it out of the cell across the plasma membrane or into internal organelles. These transporters, which include Ca2+-ATPases and Ca2+/H+ antiporters, have a critical role in preventing Ca2+ toxicity, maintaining cytosolic Ca2+ at a low resting level, and transferring Ca2+ to specific cellular locations where it is required. Many genes encoding plant Ca2+-ATPases and Ca2+/H+ antiporters have now been identified and characterised to elucidate their biochemical and genetic features. Furthermore, the use of gene knockouts has begun to provide evidence for an involvement of these Ca2+ transporters in Ca2+ signalling networks and in various aspects of plant development