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51.
Dorothee von Witzendorff Kai Maass Andreas Pich Silja Ebeling Sabine Klle Christine Kochel Mahnaz Ekhlasi-Hundrieser Hildegard Geyer Rudolf Geyer Edda Tpfer-Petersen 《Carbohydrate research》2009,344(12):1541-751
Oocyte maturation is a prerequisite for successful fertilization. Growing evidence suggests that not only the oocyte but also the surrounding zona pellucida has to undergo maturational changes. In the pig, two-dimensional electrophoretic analysis demonstrated an acidic shift of the zona pellucida glycoproteins of about 1.5–2.0 pH units during the maturation process. These findings were corroborated by histological studies that indicated the synthesis of acidic glycoconjugates in the cumulus cells and an increased occurrence of acidic glycans in the zona pellucida after oocyte maturation. In order to provide structural data on prepuberal zona pellucida N-glycosylation, N-glycans were released from prepuberal zona pellucida glycoproteins by N-glycosidase F and studied by mass spectrometry before and after desialylation and treatment with endo-β-galactosidase. Our results verified the presence of high-mannose-type Man5GlcNAc2 compounds as well as diantennary N-glycans as major neutral species, whereas sialylated diantennary and triantennary species constituted the dominant non-sulfated acidic sugar chains. The major acidic N-glycans of prepuberal animals, however, represented mono-sulfated diantennary, triantennary and tetraantennary oligosaccharides carrying, in part, N-acetyllactosamine repeating units as well as additional Neu5Ac or Neu5Gc residues. Glycans comprising more than one sulfate residue were not detected. In contrast to the literature data on zona pellucida glycoprotein-N-glycans of cyclic animals, our data thus reveal a lower degree in glycan sulfation of the prepuberal zona pellucida. 相似文献
52.
53.
Christina Biasi Hildegard Meyer Olga Rusalimova Rainer Hämmerle Christina Kaiser Christian Baranyi Holger Daims Nikolaj Lashchinsky Pavel Barsukov Andreas Richter 《Plant and Soil》2008,303(1-2):191-205
Biological soil crusts can affect seed germination and seedling establishment. We have investigated the effect of biological
soil crusts on seed water status as a potential mechanism affecting seed germination. The seed water potential of two annual
grasses, one exotic Bromus tectorum L. and another native Vulpia microstachys Nutt., were analyzed after placing the seeds on bare soil, on a crust that contains various lichens and mosses (mixed crust),
or on a crust dominated by the crustose lichen Diploschistes muscorum (Scop.) R. Sant. (Diploschistes crust). Seed water potential and germination were similar on the bare soil and the mixed crust, except for the initial germination
of V. microstachys, which was higher on the mixed crust than on the bare soil. For the two grasses studied, seed water potential was significantly
higher on the bare soil and mixed crust than on the Diploschistes crust. These differences in water potential correlated with differences in germination, which was much lower on the lichen
crust. Experiments were conducted under two watering regimens. Increasing the frequency of watering amplified the differences
in seed water potential and germination between the Diploschistes crust and the other two surfaces. For a particular watering regimen, the bare soil, mixed crust, and Diploschistes crust received the same amount of water, but they reached significantly different water potentials. Throughout the experiments,
the water potential of the soil and mixed crust remained above −0.6 MPa, while there was a marked decline in the water potential
of the Diploschistes surface to about −4 MPa. To ascertain that water was the major factor limiting germination on the Diploschistes crust, we conducted germination tests in an environment with 100% relative humidity. Under these conditions, germination
on the Diploschistes crust was similar to that on the bare soil. However, the seeds that germinated on the Diploschistes crust did not penetrate this surface and approximately 60% of their root tips became necrotic. Our results indicate that
the presence of D. muscorum can inhibit seedling establishment by two mechanisms: a reduction in seed water absorption and an increase in root tip mortality. 相似文献
54.
Julien Bernaud Axel Rossi Anny Fis Lara Gardette Ludovic Aillot Hildegard Büning Martin Castelnovo Anna Salvetti Cendrine Faivre-Moskalenko 《Journal of biological physics》2018,44(2):181-194
Virus families have evolved different strategies for genome uncoating, which are also followed by recombinant vectors. Vectors derived from adeno-associated viruses (AAV) are considered as leading delivery tools for in vivo gene transfer, and in particular gene therapy. Using a combination of atomic force microscopy (AFM), biochemical experiments, and physical modeling, we investigated here the physical properties and stability of AAV vector particles. We first compared the morphological properties of AAV vectors derived from two different serotypes (AAV8 and AAV9). Furthermore, we triggered ssDNA uncoating by incubating vector particles to increasing controlled temperatures. Our analyses, performed at the single-particle level, indicate that genome release can occur in vitro via two alternative pathways: either the capsid remains intact and ejects linearly the ssDNA molecule, or the capsid is ruptured, leaving ssDNA in a compact entangled conformation. The analysis of the length distributions of ejected genomes further revealed a two-step ejection behavior. We propose a kinetic model aimed at quantitatively describing the evolution of capsids and genomes along the different pathways, as a function of time and temperature. This model allows quantifying the relative stability of AAV8 and AAV9 particles. 相似文献
55.
Sample preservation for determination of organic compounds: microwave versus freeze-drying 总被引:10,自引:2,他引:8
Popp Marianne; Lied Wolfgang; Meyer Andreas J.; Richter Andreas; Schiller Petra; Schwitte Hildegard 《Journal of experimental botany》1996,47(10):1469-1473
In search of a reliable drying method, which might be used evenunder field conditions, microwave drying was compared to freeze-dryingof plant material. Leaves of Ananas comosus and Avicennia germinansas well as buds and phloem of Acer pseudoplatanus were usedand checked for one or more of the following substances: sugars,sugar alcohols, organic and amino acids, total nitrogen, andglycinebetaine. With most samples good agreement was achieved between the twodrying methods. Only in the case of the Ananas comosus leaves,which exhibited low pH and high water content, did appreciabledifferences occur in organic and amino acids. Besides that,sucrose was the compound most susceptible to alterations, whichwas especially evident when leaves of Sambucus nigra were driedin the two different compartments (condenser compartment, dryingbell jar) of the freeze-dryer in use. For Ananas comosus leaf samples it was shown that microwavingcan also be used prior to extraction of tissue sap. Key words: Microwave, freeze-drying, drying method, tissue sap, organic solutes 相似文献
56.
Dietrich Behne Antonios Kyriakopoeulos Christian Weiss-Nowak Margrit Kalckloesch Christian Westphal Hildegard Gessner 《Biological trace element research》1996,55(1-2):99-110
The Se-containing proteins in 27 tissues of the rat were investigated by in vivo labeling with75Se-selenite, separation of the tissue homogenate proteins by SDS-polyacrylamide gel electrophoresis, and determination of
the labeled proteins by autoradiography. By using Se-depleted rats and a75Se-tracer with a high specific activity, Se compounds present at only very low concentrations could be detected. Besides the
13 Se-containing proteins previously described, for which apparent molecular masses of 12, 15, 18, 20, 22, 25, 28, 34, 56,
60, 65, 70, and 75 kD have been found here, a further 1575Se-labeled bands, with apparent molecular masses of 8, 10, 15.5, 16.5, 24, 32, 34.5, 38, 40, 41, 44, 45, 46.5, 53 and 116
kD could be distinguished. Two-dimensional separation of the kidney homogenate proteins showed that some of the Se-containing
bands could be resolved into several labeled spots. Most of the newly found compounds were present in various tissues, but
with some the enrichment in certain tissues suggested specific sites of action. 相似文献
57.
Neutral complex-type N-glycans of the envelope glycoprotein 120 of HIV-2, propagated in different host cells, display cell-type
specific variations. In order to identify typical structural elements, glycans were analysed by gel filtration, by enzymic
sequencing and, in part, by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The characteristic
substituents of di- tri- and tetraantennary carbohydrate units thus observed include N-acetyllactosamine repeats, bisecting N-acetylglucosamine and fucose linked to the chitobiose core as well as to N-acetyllactosamine antennae. Each glycoprotein preparation displayed a characteristic set of glycoforms.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
58.
Wagner Ralf; Liedtke Steffen; Kretzschmar Evelyne; Geyer Hildegard; Geyer Rudolf; Klenk Hans-Dieter 《Glycobiology》1996,6(2):165-175
Spodoptera frugiperda (Sf9)-cells differ markedly in their proteinglycosylation capacities from vertebrate cells in that theyare not able to generate complex type oligosaccharide side chains.In order to improve the oligosaccha ride processing propertiesof these cells we have used baculovirus vectors for expressionof human (ß1,2-N-acetylglucosaminyltransferase I (hGNT-I),the enzyme catalysing the crucial step in the pathway leadingto complex type N-glycans in vertebrate cells. One vector (Bac/GNT)was designed to express unmodified GNT-I protein, the secondvector (Bac/tagGNT) to express GNT-I protein with a tag epitopefused to its N-terminus. In Sf9-cells infected with Bac/tagGNT-virusa protein of about 50 kDa representing hGNT-I was detected withan antiserum directed against the tag epitope. HGNT-I activitywas increased at least threefold in lysates of infected cellswhen N-acetylglucosamine (GlcNAc)-free ovalbumine was used assubstrate. To monitor hGNT-I activity in intact Sf9-cells, theglycosylation of coexpressed fowl plague virus hemagglutinin(HA) was investigated employing a galactosylation assay andchromatographic analysis of isolated HA N-glycans. Coexpressionof hGNT-I resulted in an at least fourfold increase of HA carryingterminal GlcNAc-residues. The only structure detectable in thisfraction was GlcNAcMan3GlcNAc2. These results show that hGNT-Iis functionally active in Sf9-cells and that the N-glycans ofproteins expressed in the baculovirus/insect cell system areelongated by coexpression of glycosyltransferases of vertebrateorigin. Complete complex type oligosaccharide side chains werenot observed when hGNT-I was overexpressed, thus supportingthe concept that Sf9-cells do not contain glycosyltransferasesacting after hGNT-I. ß1,2-N-acetylglucosaminyltransferase I baculovirus expression of recombinant protiens N-glycosylation in Sf9-cells 相似文献
59.
Hiromi?Ito Hiroyuki?Kaji Akira?Togayachi Parastoo?Azadi Mayumi?Ishihara Rudolf?Geyer Christina?Galuska Hildegard?Geyer Kazuaki?Kakehi Mitsuhiro?Kinoshita Niclas?G.?Karlsson Chunsheng?Jin Koichi?Kato Hirokazu?Yagi Sachiko?Kondo Nana?Kawasaki Noritaka?Hashii Daniel?Kolarich Kathrin?Stavenhagen Nicolle?H.?Packer Morten?Thaysen-Andersen Miyako?Nakano Naoyuki?Taniguchi Ayako?Kurimoto Yoshinao?Wada Michiko?Tajiri Pengyuan?Yang Weiqian?Cao Hong?Li Pauline?M.?RuddEmail author Hisashi?Narimatsu 《Glycoconjugate journal》2016,33(3):405-415
The Human Disease Glycomics/Proteome Initiative (HGPI) is an activity in the Human Proteome Organization (HUPO) supported by leading researchers from international institutes and aims at development of disease-related glycomics/glycoproteomics analysis techniques. Since 2004, the initiative has conducted three pilot studies. The first two were N- and O-glycan analyses of purified transferrin and immunoglobulin-G and assessed the most appropriate analytical approach employed at the time. This paper describes the third study, which was conducted to compare different approaches for quantitation of N- and O-linked glycans attached to proteins in crude biological samples. The preliminary analysis on cell pellets resulted in wildly varied glycan profiles, which was probably the consequence of variations in the pre-processing sample preparation methodologies. However, the reproducibility of the data was not improved dramatically in the subsequent analysis on cell lysate fractions prepared in a specified method by one lab. The study demonstrated the difficulty of carrying out a complete analysis of the glycome in crude samples by any single technology and the importance of rigorous optimization of the course of analysis from preprocessing to data interpretation. It suggests that another collaborative study employing the latest technologies in this rapidly evolving field will help to realize the requirements of carrying out the large-scale analysis of glycoproteins in complex cell samples. 相似文献
60.
Tobias Maria Böckers Hildegard Sourgens Werner Wittkowski Andrea Jekat Franz Pera 《Cell and tissue research》1990,260(2):403-408
Summary The pars tuberalis (pt) of the adenohypophysis is unique in its close spatial relationship to the neurohemal contact area of the median eminence. The morphology of pt-specific secretory cells does not resemble cell types of the pars distalis (pd); the functional role of these cells within the endocrine system is still unknown. One group of young mature female Wistar rats received propylthiouracil (PTU), a second group thyroxine (T4) (10 mg/l each in drinking water) from about 3 weeks prior to the expected pregnancy and throughout the experiment. On gestation day 20, the fetuses were obtained by laparatomy. Serial sections from the rostral portion of the pt and from the pd were immunostained using the peroxidase-antiperoxidase method. TSH concentrations were determined by RIA in serum and pituitaries; T4 was measured in serum. An antiserum against rat (r) TSH revealed a moderate positive reaction of nearly all cells of the pt in the control group. In both experimental groups the pt-specific cells showed weak or no immunoreactivity. Sections of all groups were negative with anti(r)-LH,-GH,-PRL. In contrast to controls, only a few immature TSH-cells could be found in sections of the pd in the T4-group, while concentrations of TSH in blood and hypophysis were very low. TSH-cells in the PTU-group were enlarged and less intensely stained. TSH-concentrations were decreased in the hypophysis, blood levels were elevated. All sections of the pd-specific cell populations showed positive immunoreactions with anti(r)-LH,-GH,-PRL. The present results suggest that pt-specific secretory cells of the fetal rat possess TSH immunoreactivity but do not resemble the thyrotropes of the pd. Marked differences in immunoreactivity displayed by the experimental groups indicate that pt-specific cells respond to changes in the fetal thyroid status and are a component of the thyroid-regulating system in addition to the thyrotropes of the pd. This novel aspect of pt function is discussed in connection with recent results concerning melatonin receptors found in the pt and the inhibitory influence of the pineal gland exerted on the thyroid gland.The study was supported by the Deutsche Forschungsgemeinschaft (Wi 558/4-1) 相似文献