Novel interactions between urokinase and its receptor

Urokinase-type plasminogen activator (uPA) binds to its receptor (uPAR) with a K(d) of about 1 nm. The catalytic activity of the complex is apparent at uPA concentrations close to K(d). Other functions of the complex, such as signal transduction, are apparent at much higher concentrations (35-60 nm). In the present study, we show that uPA and recombinant soluble uPAR (suPAR), at concentrations that exceed the K(d) and the theoretical saturation levels (10-80 nm), establish novel interactions that lead to a further increase in the activity of the single-chain uPA (scuPA)/suPAR and two-chain uPA (tcuPA)/suPAR complexes. Experiments performed using dynamic light scattering, gel filtration, and electron microscopy techniques indicate that suPAR forms dimers and oligomers. The three techniques provide evidence that the addition of an equimolar concentration of scuPA leads to the dissociation of these dimers and oligomers. Biacore data show that suPAR dimers and oligomers bind scuPA with decreased affinity when compared with monomers. We postulate that uPAR is present in equilibrium between oligomer/dimer/monomer forms. The binding of uPA to suPAR dimers and oligomers occurs with lower affinity than the binding to monomer. These novel interactions regulate the activity of the resultant complexes and may be involved in uPA/uPAR mediated signal transduction.     

Comparison of two eukaryotic systems for the expression of VP6 protein of rotavirus specie A: transient gene expression in HEK293-T cells and insect cell-baculovirus system

The VP6 protein of rotavirus A (RVA) is a target antigen used for diagnostic assays and also for the development of new RVA vaccines. We have compared the expression of VP6 protein in human embryonic kidney (HEK293-T) cells with results obtained using a well-established insect cell-baculovirus system. The recombinant VP6 (rVP6) expressed in HEK293-T cells did not present degradation and also retained the ability to form trimers. In the insect cell-baculovirus system, rVP6 was expressed at higher levels and with protein degradation as well as partial loss of ability to form trimers was observed. Therefore, HEK293-T cells represent a less laborious alternative system than insect cells for expression of rVP6 from human RVA.     

Proteomic characterization of seeds from yellow lupin (Lupinus luteus L.)

Yellow lupin (Lupinus luteus L.) is a legume crop containing a large amount of protein in its seeds. In this study, we constructed a seed‐protein catalog to provide a foundation for further study of the seeds. A total of 736 proteins were identified in 341 2DE spots by nano‐LC‐MS/MS. Eight storage proteins were found as multiple spots in the 2DE gels. The 736 proteins correspond to 152 unique proteins as shown by UniRef50 clustering. Sixty‐seven of the 152 proteins were associated with KEGG‐defined pathways. Of the remaining proteins, 57 were classified according to a GO term. The functions of the remaining 28 proteins have yet to be determined. This is the first yellow lupin seed–protein catalog, and it contains considerably more data than previously reported for white lupin (L. albus L.).     

A remarkable new species of <Emphasis Type="Italic">Ormosia</Emphasis> (Leguminosae: Papilionoideae: Sophoreae) from Bahian Atlantic Rain Forest,Brazil

Ormosia timboënsis is described and illustrated as a new species based on fruit and leaf material collected in a fragment of Atlantic Rain Forest in central Bahia State, Brazil. This new species can be recognized by possessing the largest seed and hilum of those that have been reported in Ormosia. In addition, O. timboënsis has leaves that in combination with the fruit characters do not match any species currently described in the genus.     

Measurement of yeast concentrations in liquid hydrocarbon fermentations: influence of experimental conditions and statistical significance of the results obtained

The influence of the following factors on the measurement of yeast concentration in liquid hydrocarbon fermentations was studied: surfactant, type (Tween 20, Tween 80, and G 3300), yeast concentration (0.215 to 0.272 and 3.37 to 4.08 g/liter, as dry matter), oil concentration (8.32 and 61.6 g/liter), surfactant, concentration (0.515, 1.030, 1.545, and 2.060 g/liter), and time of contact of the surfactant with the oil-yeast-aqueous medium mixture (2 and 10 min). The statistical significance of the obtained results was determined.     

Imprint cytology in the intraoperative diagnosis of malignant melanoma

Imprints were prepared from 73 pigmented skin lesions, 19 of which were diagnosed as malignant melanoma. The cytologic findings in malignant melanoma, large clusters of cells with loss of cellular cohesiveness and large pleomorphic nuclei, were positive in 17 of the 19 cases. In other malignant and benign pigmented lesions the few cells adherent to the glass showed characteristic cytologic features of the particular lesion. Imprint cytology seems to be a valuable adjunct to the examination of frozen sections for the intraoperative diagnosis of malignant melanoma.