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991.
Katharina R?ltgen Weihong Qi Marie-Thérèse Ruf Ernestina Mensah-Quainoo Sacha J. Pidot Torsten Seemann Timothy P. Stinear Michael K?ser Dorothy Yeboah-Manu Gerd Pluschke 《PLoS neglected tropical diseases》2010,4(7)
Buruli ulcer (BU) is an emerging necrotizing disease of the skin and subcutaneous tissue caused by Mycobacterium ulcerans. While proximity to stagnant or slow flowing water bodies is a risk factor for acquiring BU, the epidemiology and mode of M. ulcerans transmission is poorly understood. Here we have used high-throughput DNA sequencing and comparisons of the genomes of seven M. ulcerans isolates that appeared monomorphic by existing typing methods. We identified a limited number of single nucleotide polymorphisms (SNPs) and developed a real-time PCR SNP typing method based on these differences. We then investigated clinical isolates of M. ulcerans on which we had detailed information concerning patient location and time of diagnosis. Within the Densu river basin of Ghana we observed dominance of one clonal complex and local clustering of some of the variants belonging to this complex. These results reveal focal transmission and demonstrate, that micro-epidemiological analyses by SNP typing has great potential to help us understand how M. ulcerans is transmitted. 相似文献
992.
Shinobu Yasuo Marco Koch Helmut Schmidt Simone Ziebell Joerg Bojunga Gerd Geisslinger Horst-Werner Korf 《Cell and tissue research》2010,340(1):127-136
The hypophysial pars tuberalis (PT), an important interface between neuroendocrine brain centers (hypothalamus, pineal organ)
and the pars distalis (PD) of the hypophysis, plays a central role in regulating seasonal reproduction and prolactin release.
However, the signaling molecules that transmit photoperiodic information from the PT to the PD and control prolactin release
(the so-called “tuberalins”) have not yet been identified, despite an intense search for more than three decades. Here, we
demonstrate an endocannabinoid system in the PT of the Syrian hamster, a photoperiodic species. By means of in situ hybrization,
the PT was found to express N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD), fatty acid amide hydrolase (FAAH), sn-1-selective diacylglycerol lipases (DAGLα and DAGLβ), and monoacylglycerol lipase (MAGL), enzymes involved in endocannabinoid
synthesis and degradation. The expression of NAPE-PLD, FAAH, and DAGLα was confirmed by immunohistochemistry. Expression and
protein levels of DAGLs controlling the synthesis of 2-arachidonoyl glycerol (2-AG), a major endocannabinoid, were upregulated
in the PT of Syrian hamsters kept under long-day conditions. Consequently, 2-AG levels were increased in the PT of these hamsters.
A primary target of 2-AG, the cannabinoid receptor 1 (CB1), was expressed in the PD. Double-immunolabeling revealed that most
of the CB1-immunoreactive cells in the PD were folliculostellate cells that were also immunoreactive for S-100 protein. Thus,
the PT comprises an endocannabinoid system, and 2-AG may act as a photoperiodic messenger from the PT to the PD for the regulation
of hypophysial hormonal secretion. 相似文献
993.
Wanisa Salaemae Muhammad Junaid Chanan Angsuthanasombat Gerd Katzenmeier 《Journal of biomedical science》2010,17(1):68
Background
The dengue virus two-component protease NS2B/NS3 mediates processing of the viral polyprotein precursor and is therefore an important determinant of virus replication. The enzyme is now intensively studied with a view to the structure-based development of antiviral inhibitors. Although 3-dimensional structures have now been elucidated for a number of flaviviral proteases, enzyme-substrate interactions are characterized only to a limited extend. The high selectivity of the dengue virus protease for the polyprotein precursor offers the distinct advantage of designing inhibitors with exquisite specificity for the viral enzyme. To identify important determinants of substrate binding and catalysis in the active site of the dengue virus NS3 protease, nine residues, L115, D129, G133, T134, Y150, G151, N152, S163 and I165, located within the S1 and S2 pockets of the enzyme were targeted by alanine substitution mutagenesis and effects on enzyme activity were fluorometrically assayed. 相似文献994.
Corrado Viotti Julia Bubeck York-Dieter Stierhof Melanie Krebs Markus Langhans Willy van den Berg Walter van Dongen Sandra Richter Niko Geldner Junpei Takano Gerd Jürgens Sacco C. de Vries David G. Robinson Karin Schumacher 《The Plant cell》2010,22(4):1344-1357
Plants constantly adjust their repertoire of plasma membrane proteins that mediates transduction of environmental and developmental signals as well as transport of ions, nutrients, and hormones. The importance of regulated secretory and endocytic trafficking is becoming increasingly clear; however, our knowledge of the compartments and molecular machinery involved is still fragmentary. We used immunogold electron microscopy and confocal laser scanning microscopy to trace the route of cargo molecules, including the BRASSINOSTEROID INSENSITIVE1 receptor and the REQUIRES HIGH BORON1 boron exporter, throughout the plant endomembrane system. Our results provide evidence that both endocytic and secretory cargo pass through the trans-Golgi network/early endosome (TGN/EE) and demonstrate that cargo in late endosomes/multivesicular bodies is destined for vacuolar degradation. Moreover, using spinning disc microscopy, we show that TGN/EEs move independently and are only transiently associated with an individual Golgi stack. 相似文献
995.
Haiyan Sun Hancheng Wang Gerd Stammler Jianxia Ma Mingguo Zhou 《Journal of Phytopathology》2010,158(4):244-252
During 2006–2008, 572 isolates of Phytophthora capsici were collected from seven provinces in China, and their sensitivities to three carboxylic acid amides (CAA), dimethomorph, flumorph and pyrimorph were determined. Of these isolates, 90 isolates without a history of exposure to CAA fungicides (CAAs) were used to set up the baseline sensitivity. Baseline EC50 values ranged from 0.122 to 0.203 (mean ± SD, 0.154 ± 0.022) μg ml?1 for dimethomorph, from 0.301 to 0.487 (mean ± SD, 0.373 ± 0.043) μg ml?1 for flumorph and from 0.557 to 0.944 (mean ± SD, 0.712 ± 0.082) μg ml?1 for pyrimorph, respectively. The other 482 isolates were tested with a single discriminatory dose and were completely inhibited at 0.5 μg ml?1 of dimethomorph. Four CAA‐resistant mutants were generated by repeated exposure to dimethomorph in vitro. As compared to the parental wild‐type isolate, the four CAA‐resistant mutants showed similar fitness in hyphal growth, sporulation in vitro and pathogenicity in vivo. Mutants resistant to CAAs in the in vitro assay caused visible lesions on pepper stems or roots treated with the recommended dose of dimethomorph. Previous studies upon the mode of action of CAAs suggested that these fungicides maybe inhibit phospholipid biosynthesis and that the primary target could be the cholinephosphotranferase (CPT), which is referred to aminoalcoholphosphotransferases (AAPTs). We sequenced and analyzed two CPT (AAPT1 and AAPT2) genes in P. capsici. Based on the cDNA sequence, we found that the AAPT1 and AAPT2 gene span 1538 and 1459 bp and were interrupted by five and three introns, respectively. There was no difference between the parental wild‐type isolate and the four CAA‐resistant mutants in the amino acid sequences of AAPT1 and AAPT2 gene. So, it was assumed that the resistance to dimethomorph was not due to mutations in the amino acid sequence of these two possible target genes. 相似文献
996.
997.
Shuang Chen Hollis Lau Yan Brodsky Gerd R Kleemann Ramil F Latypov 《Protein science : a publication of the Protein Society》2010,19(6):1191-1204
This study introduces a novel analytical approach for studying aggregation and phase separation of monoclonal antibodies (mAbs). The approach is based on using analytical scale cation‐exchange chromatography (CEX) for measuring the loss of soluble monomer in the case of individual and mixed protein solutions. Native CEX outperforms traditional size‐exclusion chromatography in separating complex protein mixtures, offering an easy way to assess mAb aggregation propensity. Different IgG1 and IgG2 molecules were tested individually and in mixtures consisting of up to four protein molecules. Antibody aggregation was induced by four different stress factors: high temperature, low pH, addition of fatty acids, and rigorous agitation. The extent of aggregation was determined from the amount of monomeric protein remaining in solution after stress. Consequently, it was possible to address the role of specific mAb regions in antibody aggregation by co‐incubating Fab and Fc fragments with their respective full‐length molecules. Our results revealed that the relative contribution of Fab and Fc regions in mAb aggregation is strongly dependent on pH and the stress factor applied. In addition, the CEX‐based approach was used to study reversible protein precipitation due to phase separation, which demonstrated its use for a broader range of protein–protein association phenomena. In all cases, the role of Fab and Fc was clearly dissected, providing important information for engineering more stable mAb‐based therapeutics. 相似文献
998.
Margot Grandl Salim Maa Bared Gerhard Liebisch Tobias Werner Stefan Barlage Gerd Schmitz 《Cytometry. Part A》2006,69(3):189-191
Atherosclerosis is characterized by the generation of lipid-loaded macrophage-derived foam cells. To study the effect of different types of atherogenic lipoproteins, human macrophages were loaded with enzymatically degraded low density lipoprotein (E-LDL) or oxidized LDL (Ox-LDL). Cellular cholesterol content was increased by E-LDL, whereas Ox-LDL increased the ceramide content. Cell surface expression analysis by flow cytometry and confocal microscopy revealed that Ox-LDL increased ceramide and lactosylceramide expression compared to E-LDL loading and induced ceramide rafts, whereas loading with E-LDL induced cholesterol-rich microdomains. Formation of different rafts may have consequences for raft associated signaling in cholesterol homeostasis and apoptosis in human macrophages. 相似文献
999.
Gerd Gäde† Lutz Auerswald† Reinhard Predel Heather G. Marco† 《Physiological Entomology》2004,29(1):84-93
Abstract. The metabolites that are generally used by insects during exercise are present in quite different concentrations in the haemolymph of the backswimmer Notonecta glauca L. Lipids are most abundant (between 10 and 20 mg/mL), whereas carbohydrates (2–3 mg/mL) and proline (approximately 1 mg/mL) are at very low concentrations. Injection of an extract of conspecific corpora cardiaca causes pronounced hyperlipaemia in the backswimmer. A neuropeptide with the same effect was isolated from the corpora cardiaca in a single high-performance liquid chromatography (HPLC) step; the primary sequence was deduced from mass spectrometric measurements (matrix-assisted laser desorption/ionization-time of flight and electrospray quadrupol time-of-flight mass spectrometry) of whole corpora cardiaca, and the mass was confirmed in the HPLC fraction that had adipokinetic activity. The biologically active octapeptide has the sequence pGlu-Val-Asn-Phe-Ser-Pro-Ser-Trp amide, which was characterized previously from the corpora cardiaca of the Emperor dragonfly, Anax imperator , and denoted Anaim-adipokinetic hormone (AKH). The synthetic Anaim-AKH peptide causes lipid mobilization when injected at a dose of 1 pmol into N. glauca . When other synthetic AKH members that occur in Hemiptera are injected into N. glauca at the same dose, the hyperlipaemic responses are significantly lower than after injection of Anaim-AKH. Because only lipids increase upon activity, such as continuous swimming for 1 h or during a 1-h rest period after a 3-min flight episode in the laboratory, it is assumed that Anaim-AKH serves as a true adipokinetic hormone in the backswimmer during bouts of natural swimming and flight. 相似文献
1000.
Weihong Du Zhicheng Xia Sylvia Dewilde Luc Moens Gerd N La Mar 《European journal of biochemistry》2003,270(13):2707-2720
The solution molecular and electronic structures of the active site in the extremely O2-avid hemoglobin from the trematode Paramphistomum epiclitum have been investigated by 1H NMR on the cyanomet form in order to elucidate the distal hydrogen-bonding to a ligated H-bond acceptor ligand. Comparison of the strengths of dipolar interactions in solution with the alternate crystal structures of methemoglobin establish that the solution structure of wild-type Hb more closely resembles the crystal structure of the recombinant wild-type than the true wild-type met-hemoglobin. The distal Tyr66(E7) is found oriented out of the heme pocket in solution as found in both crystal structures. Analysis of dipolar contacts, dipolar shift and paramagnetic relaxation establishes that the Tyr32(B10) hydrogen proton adopts an orientation that allows it to make a strong H-bond to the bound cyanide. The observation of a significant isotope effect on the heme methyl contact shifts confirms a strong contact between the Tyr32(B10) OH and the ligated cyanide. The quantitative determination of the orientation and anisotropies of the paramagnetic susceptibility tensor reveal that the cyanide is tilted approximately 10 degrees from the heme normal so as to avoid van der Waals overlap with the Tyr32(B10) Oeta. The pattern of heme contact shifts with large low-field shifts for 7-CH3 and 18-CH3 is shown to arise not from the 180 degrees rotation about the alpha-gamma-meso axis, but due to the approximately 45 degrees rotation of the axial His imidazole ring, relative to that in mammalian globins. 相似文献