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91.
Evolution of Afrotropical freshwater crab lineages obscured by morphological convergence 总被引:1,自引:0,他引:1
Daniels SR Cumberlidge N Pérez-Losada M Marijnissen SA Crandall KA 《Molecular phylogenetics and evolution》2006,40(1):227-235
We use sequence data derived from six DNA gene loci to examine evolutionary and biogeographic affinities among all freshwater crab families. With an emphasis on the Afrotropical fauna that includes Africa, Madagascar, and the Seychelles, we test the proposed Gondwanan cladogenesis of the group. Phylogenetic results demonstrate that contemporary distribution patterns of freshwater crab lineages are incongruent with the expected area cladogram of continental fragmentation. Instead, our phylogenetic estimate and divergence time estimation indicate a post-Gondwanan, early Cretaceous cladogenesis for freshwater crabs implying that the acquisition of a freshwater lifestyle was achieved more recently. A dispersal hypothesis as opposed to vicariance appears to best explain the contemporary distribution pattern of this group. However, our results do not explicitly disprove a Gondwanan origin for the Afrotropical freshwater crabs. Alarmingly, these results suggest that most of the currently recognized freshwater crab families are unreliable taxonomic groupings since virtually no Afrotropical freshwater crab families formed monophyletic units thus obscuring inferred biogeographic relationships. Convergence in characters associated with the terminal segment of the mandibular palp is clearly a pervasive obstacle in the taxonomy of this group. 相似文献
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Velden J Paust HJ Hoxha E Turner JE Steinmetz OM Wolf G Jabs WJ Özcan F Beige J Heering PJ Schröder S Kneißler U Disteldorf E Mittrücker HW Stahl RA Helmchen U Panzer U 《American journal of physiology. Renal physiology》2012,302(12):F1663-F1673
Interleukin-17A (IL-17) promotes inflammatory renal tissue damage in mouse models of crescentic glomerulonephritis, including murine experimental autoimmune anti-myeloperoxidase glomerulonephritis, which most likely depends on IL-17-producing Th17 cells. In human anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, however, the cellular sources of IL-17 remain to be elucidated. Therefore, we analyzed human kidney biopsies of active necrotizing and crescentic ANCA-associated glomerulonephritis by immunohistochemistry using an IL-17-specific antibody and by immunofluorescent colocalization with cell type markers. We detected numerous IL-17-expressing (IL-17(+)) cells in the glomeruli and in the tubulointerstitium. Unexpectedly, most of these IL-17(+) cells were polymorphonuclear neutrophilic granulocytes, while IL-17(+) T cells and IL-17(+) mast cells were present at significantly lower frequencies. IL-17 was not detected in other infiltrating or resident kidney cells. In those patients who had not received immunosuppressive treatment before biopsy, serum creatinine levels were positively correlated with tubulointerstitial IL-17(+) neutrophils as well as IL-17(+) T cells. Furthermore, we could demonstrate that purified human blood neutrophils expressed IL-17 protein and released it upon stimulation in vitro. In conclusion, these results support a pathogenic role for IL-17 in human ANCA-associated glomerulonephritis. Our data suggest that in the acute stage of the disease neutrophils may act as an important immediate-early innate source of IL-17 and may thereby initiate and promote ongoing renal inflammation. IL-17 may thus be a target for treating acute ANCA-associated glomerulonephritis. 相似文献
94.
Influence of drying on the secondary structure of intrinsically disordered and globular proteins 总被引:1,自引:0,他引:1
Hundertmark M Popova AV Rausch S Seckler R Hincha DK 《Biochemical and biophysical research communications》2012,417(1):122-128
Circular dichroism (CD) spectroscopy of five Arabidopsis late embryogenesis abundant (LEA) proteins constituting the plant specific families LEA_5 and LEA_6 showed that they are intrinsically disordered in solution and partially fold during drying. Structural predictions were comparable to these results for hydrated LEA_6, but not for LEA_5 proteins. FTIR spectroscopy showed that verbascose, but not sucrose, strongly affected the structure of the dry proteins. The four investigated globular proteins were only mildly affected by drying in the absence, but strongly in the presence of sugars. These data highlight the larger structural flexibility of disordered compared to globular proteins and the impact of sugars on the structure of both disordered and globular proteins during drying. 相似文献
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98.
Wälde S Thakar K Hutten S Spillner C Nath A Rothbauer U Wiemann S Kehlenbach RH 《Traffic (Copenhagen, Denmark)》2012,13(2):218-233
In vertebrates, the nuclear pore complex (NPC), the gate for transport of macromolecules between the nucleus and the cytoplasm, consists of approximately 30 different nucleoporins (Nups). The Nup and SUMO E3-ligase Nup358/RanBP2 are the major components of the cytoplasmic filaments of the NPC. In this study, we perform a structure-function analysis of Nup358 and describe its role in nuclear import of specific proteins. In a screen for nuclear proteins that accumulate in the cytoplasm upon Nup358 depletion, we identified proteins that were able to interact with Nup358 in a receptor-independent manner. These included the importin α/β-cargo DBC-1 (deleted in breast cancer 1) and DMAP-1 (DNA methyltransferase 1 associated protein 1). Strikingly, a short N-terminal fragment of Nup358 was sufficient to promote import of DBC-1, whereas DMAP-1 required a larger portion of Nup358 for stimulated import. Neither the interaction of RanGAP with Nup358 nor its SUMO-E3 ligase activity was required for nuclear import of all tested cargos. Together, Nup358 functions as a cargo- and receptor-specific assembly platform, increasing the efficiency of nuclear import of proteins through various mechanisms. 相似文献
99.
Willenbrock S Braun O Baumgart J Lange S Junghanss C Heisterkamp A Nolte I Bullerdiek J Murua Escobar H 《Cytokine》2012,57(2):210-220
BackgroundMammary neoplasias are one of the most frequent and spontaneously occurring malignancies in dogs and humans. Due to the similar anatomy of the mammary gland in both species, the dog has become an important animal model for this cancer entity. In human breast carcinomas, the overexpression of a protein named high-mobility group box 1 (HMGB1) was reported. Cells of the immune system were described to release HMGB1 actively exerting cytokine function. Thereby it is involved in the immune system activation, tissue repair, and cell migration. Passive release of HMGB1 by necrotic cells at sites of tissue damage or in necrotic hypoxic regions of tumors induces cellular responses e.g. release of proinflammatory cytokines leading to elevated inflammatory response and neo-vascularization of necrotic tumor areas.Herein we investigated if a time-dependent stimulation with the separately applied proinflammatory cytokines TNF-α and IFN-γ can cause secretion of HMGB1 in a non-immune related HMGB1-non-secreting epithelial canine mammary cell line (MTH53A) derived from non-neoplastic tissue.MethodsThe canine cell line was transfected with recombinant HMGB1 bicistronic expression vectors and stimulated after transfection with the respective cytokine independently for 6, 24 and 48 h. HMGB1 protein detection was performed by Western blot analysis and quantified a by enzyme-linked immunosorbent assay. Live cell laser scanning multiphoton microscopy of MTH53A cells expressing a HMGB1–GFP fusion protein was performed in order to examine, if secretion of HMGB1 under cytokine stimulating conditions is also visible by fluorescence imaging.ResultsThe observed HMGB1 release kinetics showed a clearly time-dependent manner with a peak release 24 h after TNF-α stimulation, while stimulation with IFN-γ had only small effects on the HMGB1 release. Multiphoton HMGB1 live cell microscopy showed diffuse cell membrane structure changes 29 h after cytokine-stimulation but no clear secretion of HMGB1–GFP after TNF-α stimulation was visible.ConclusionOur results demonstrate that non-immune HMGB1-non-secreting cells of epithelial origin derived from mammary non-neoplastic tissue can be induced to release HMGB1 by single cytokine application. This indicates that tumor and surrounding tissue can be stimulated by tumor present inflammatory and necrotic cytokines to release HMGB1 acting as neo-vascularizing factor thus promoting tumor growth. 相似文献
100.
Claudia Maletzki Saskia Stier Ulrike Gruenert Michael Gock Christiane Ostwald Friedrich Prall Michael Linnebacher 《PloS one》2012,7(12)