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End date: 2010 × Start date: 2010 × Subject: article ×

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    Keratin homogeneity in the tail feathers of Pavo cristatus and Pavo cristatus mut. alba
    (San Diego, Calif. : Elsevier, 2010) Pabisch, S.; Puchegger, S.; Kirchner, H.O.K.; Weiss, I.M.; Peterlik, H.
    The keratin structure in the cortex of peacocks' feathers is studied by X-ray diffraction along the feather, from the calamus to the tip. It changes considerably over the first 5. cm close to the calamus and remains constant for about 1. m along the length of the feather. Close to the tip, the structure loses its high degree of order. We attribute the X-ray patterns to a shrinkage of a cylindrical arrangement of β-sheets, which is not fully formed initially. In the final structure, the crystalline beta-cores are fixed by the rest of the keratin molecule. The hydrophobic residues of the beta-core are locked into a zip-like arrangement. Structurally there is no difference between the blue and the white bird. © 2010 Elsevier Inc.
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    A novel, low-volume method for organ culture of embryonic kidneys that allows development of cortico-medullary anatomical organization
    (San Francisco, Calif. : Public Library of Science, 2010) Sebinger, D.D.R.; Unbekandt, M.; Ganeva, V.V.; Ofenbauer, A.; Werner, C.; Davies, J.A.
    Here, we present a novel method for culturing kidneys in low volumes of medium that offers more organotypic development compared to conventional methods. Organ culture is a powerful technique for studying renal development. It recapitulates many aspects of early development very well, but the established techniques have some disadvantages: in particular, they require relatively large volumes (1-3 mls) of culture medium, which can make high-throughput screens expensive, they require porous (filter) substrates which are difficult to modify chemically, and the organs produced do not achieve good cortico-medullary zonation. Here, we present a technique of growing kidney rudiments in very low volumes of medium-around 85 microliters-using silicone chambers. In this system, kidneys grow directly on glass, grow larger than in conventional culture and develop a clear anatomical cortico-medullary zonation with extended loops of Henle. © 2010 Sebinger et al.
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    Analyses and localization of pectin-like carbohydrates in cell wall and mucilage of the green alga Netrium digitus
    (Wien [u.a.] : Springer, 2010) Eder, M.; Lütz-Meindl, U.
    The unicellular, simply shaped desmid Netrium digitus inhabiting acid bog ponds grows in two phases. Prior to division, the cell elongates at its central zone, whereas in a second phase, polar tip growth occurs. Electron microscopy demonstrates that Netrium is surrounded by a morphologically homogeneous cell wall, which lacks pores. Immunocytochemical and biochemical analyses give insight into physical wall properties and, thus, into adaptation to the extreme environment. The monoclonal antibodies JIM5 and JIM7 directed against pectic epitopes with different degrees of esterification label preferentially growing wall zones in Netrium. In contrast, 2F4 marks the cell wall only after experimental de-esterification. Electron energy loss spectroscopy reveals Ca-binding capacities of pectins and gives indirect evidence for the degree of their esterification. An antibody raised against Netrium mucilage is not only specific to mucilage but also recognizes wall components in transmission electron microscopy and dot blots. These results indicate a smooth transition between mucilage and the cell wall in Netrium. © 2009 The Author(s).
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    Volume fraction determination of binary liquid mixtures by measurement of the equalization wavelength
    (Basel : MDPI, 2010) Martincek, I.; Pudis, D.; Kacik, D.; Schuster, K.
    A method for determination of the volume fraction in binary liquid mixtures by measurement of the equalization wavelength of intermodal interference of modes LP01 and LP11 in a liquid core optical fiber is presented in this paper. This method was studied using a liquid core optical fiber with fused silica cladding and a core made up of a binary silicon oil/chloroform liquid mixture with different volume fractions of chloroform. The interference technique used allows us to determine the chloroform volume fraction in the binary mixture with accuracy better than 0.1%. One of the most attractive advantages of presented method is very small volume of investigated mixture needed, as only a few hundred picoliters are necessary for reliable results. © 2010 by the authors.