Tumour-related enzyme alterations in the clear cell type of human renal cell carcinoma identified by two-dimensional gel electrophoresis.

To identify tumour-related enzyme alterations we have used 2D-gels to analyse the proteome from dissected malignant and benign kidney areas from patients with clear-cell-type renal carcinoma. The expression of 12 proteins was diminished in tumour. Four proteins were characterized by mass spectrometry and were identified as enoyl-CoA hydratase, alpha-glycerol-3-phosphate dehydrogenase, aldehyde dehydrogenase 1 and aminoacylase-I.     

The mutation spectrum of the facilitative glucose transporter gene SLC2A2 (GLUT2) in patients with Fanconi-Bickel syndrome

We report a total of 23 novel mutations of the SLC2A2 ( GLUT2) gene in 49 patients with a clinical diagnosis of Fanconi-Bickel syndrome (FBS). Molecular genetic analysis has now been performed in more than 50% of the 109 FBS cases from 88 families that we have been able to locate world-wide since the original report in 1949. In these 49 patients, 33 different SLC2A2 mutations (9 missense, 7 nonsense, 10 frameshift, 7 splice-site) have been detected. Thus, our results confirm that mutations of SLC2A2 are the basic defect in patients with FBS. Mutations of SLC2A2 were detected in historical FBS patients in whom some of the characteristic clinical features (hepatorenal glycogen accumulation, glucose and galactose intolerance, fasting hypoglycemia, a characteristic tubular nephropathy) and the effect of therapy were described for the first time. Mutations were also found in patients with atypical clinical signs such as intestinal malabsorption, failure to thrive, the absence of hepatomegaly, or renal hyperfiltration. No single prevalent SLC2A2 mutation was responsible for a significant number of cases. In a high percentage (74%) of FBS patients, the mutation is homozygous, so we conclude that the prevalence of SLC2A2 mutations is relatively low in most populations. No mutational hot spots within SLC2A2 or even within homologous sequences among the genes for facilitative glucose transporters were detected.     

High porosity with tiny pore constrictions and unbending pathways characterize the 3D structure of intervessel pit membranes in angiosperm xylem

Pit membranes between xylem vessels play a major role in angiosperm water transport. Yet, their three-dimensional (3D) structure as fibrous porous media remains unknown, largely due to technical challenges and sample preparation artefacts. Here, we applied a modelling approach based on thickness measurements of fresh and fully shrunken pit membranes of seven species. Pore constrictions were also investigated visually by perfusing fresh material with colloidal gold particles of known sizes. Based on a shrinkage model, fresh pit membranes showed tiny pore constrictions of ca. 20 nm, but a very high porosity (i.e. pore volume fraction) of on average 0.81. Perfusion experiments showed similar pore constrictions in fresh samples, well below 50 nm based on transmission electron microscopy. Drying caused a 50% shrinkage of pit membranes, resulting in much smaller pore constrictions. These findings suggest that pit membranes represent a mesoporous medium, with the pore space characterized by multiple constrictions. Constrictions are much smaller than previously assumed, but the pore volume is large and highly interconnected. Pores do not form highly tortuous, bent, or zigzagging pathways. These insights provide a novel view on pit membranes, which is essential to develop a mechanistic, 3D understanding of air-seeding through this porous medium.     

Experimente über das Regulationsvermögen der Blastula von Triton taeniatus und Bombinator pachypus

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Luftmelaninbildung bei Zimmertemperatur in Säugetieraugen und Haarwurzeln

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