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51.
Historical biogeography and the evolution of the latitudinal gradient of species richness in the Papionini (Primata: Cercopithecidae) 总被引:1,自引:0,他引:1
MONIKA BÖHM PETER J. MAYHEW 《Biological journal of the Linnean Society. Linnean Society of London》2005,85(2):235-246
We apply historical biogeography techniques to the macaques, baboons and their relatives (Primata: Papionini) and relate the inferred history of range shifts, and associated evolutionary events, to the latitudinal distribution of extant species, which is strongly tropical. The results of reversible parsimony, weighted ancestral area and dispersal-vicariance analyses all agree that Central Africa was part of the range of the ancestor of the tribe. Tropical regions with high current species richness (Central Africa, South-east Asia, Indonesia) have: (1) had a relatively long history of occupation, (2) experienced both a greater number and a greater average rate of speciation events and (3) given rise to more dispersal events to other regions. However, nested sister-taxon comparisons across the tribe show no overall association between differences in latitude and differences in rates of cladogenesis. Our historical reconstructions are largely consistent with previous hypotheses and fossil data, and suggest that both the passage of time since colonization and rates of cladogenesis have enhanced tropical species richness. Historical biogeography may thus considerably aid understanding of this and other spatial problems in macroecology. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 235–246. 相似文献
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We examined the possible effects of elemental mercury vapor on the liver of the female rats. We divided the animals into an untreated control group and an experimental group that was exposed to mercury vapor for 45 days. Liver samples were obtained for histological and stereological analysis. The total liver, parenchyma and sinusoid volumes were increased significantly in the mercury vapor treated group compared to controls. Also, the mean density, total number and mean nuclear diameter of hepatocytes, except for binucleated hepatocytes, was decreased in the experimental group compared to controls. Light and electron microscopy revealed alterations of liver structure of the experimental animals compared to controls. 相似文献
54.
In this study the uptake by guppies (Poecilia reticulata) of 1,2,3-trichlorobenzene (TCB) and hexachlorobenzene (HCB) from sediment-free water was compared with uptake in the presence of suspended sediment. The results show that the influence of suspended sediment on the uptake of chlorobenzenes varies with test compound. For TCB uptake was not influenced by the presence of suspended sediment. This is probably due to the large amount of the chemical which is dissolved relative to the amount which is present in the sorbed state. For the more hydrophobic HCB, the concentration found in the fish from the system with suspended sediment was significantly higher than in fish from the control experiment. 相似文献
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van der Vlist EJ Nolte-'t Hoen EN Stoorvogel W Arkesteijn GJ Wauben MH 《Nature protocols》2012,7(7):1311-1326
We provide a protocol for a high-resolution flow cytometry-based method for quantitative and qualitative analysis of individual nano-sized vesicles released by cells, as developed and previously described by our group. The method involves (i) bright fluorescent labeling of cell-derived vesicles and (ii) flow cytometric analysis of these vesicles using an optimized configuration of the commercially available BD Influx flow cytometer. The method allows the detection and analysis of fluorescent cell-derived vesicles of ~100 nm. Integrated information can be obtained regarding the light scattering, quantity, buoyant density and surface proteins of these nano-sized vesicles. This method can be applied in nanobiology to study basic aspects of cell-derived vesicles. Potential clinical applications include the detailed analysis of vesicle-based biomarkers in body fluids and quality control analysis of (biological) vesicles used as therapeutic agents. Isolation, fluorescent labeling and purification of vesicles can be done within 24 h. Flow cytometer setup, calibration and subsequent data acquisition can be done within 2-4 h by an experienced flow cytometer operator. 相似文献
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van Bilsen JH Wagenaar-Hilbers JP Grosfeld-Stulemeijer MC van der Cammen MJ van Dijk ME van Eden W Wauben MH 《Journal of immunology (Baltimore, Md. : 1950)》2004,172(8):5063-5068
Novel therapies for rheumatoid arthritis aiming at intervention in the inflammatory process by manipulation of autoreactive T and B lymphocytes receive major interest. However, the development of such therapies is largely hampered by the lack of knowledge of self-Ags recognized during the disease process. Recently, we predicted putative T cell self-epitopes based on a computer search profile. In the present study, the predicted self-epitopes were tested for T cell recognition in two experimental arthritis models, and their arthritogenic capacity was analyzed. Fourteen of n = 51 predicted self-epitopes were recognized during experimental arthritis of which six were able to actively induce arthritis. Interestingly, three of these six peptides were derived from matrix metalloproteinases (MMP), and only T cells responsive to MMP-derived epitopes were able to passively transfer arthritis to naive rats. Moreover, we demonstrate the presence of Abs to MMP-3 during the course of adjuvant arthritis. Together these data indicate that MMPs play a pivotal role as target for T and B cells during the development of inflammatory arthritis. This finding sheds new light on the pathophysiological role of MMPs during arthritis and opens novel possibilities for Ag-specific immunotherapy. 相似文献
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Genetic manipulation of major P-fimbrial subunits and consequences for formation of fimbriae. 总被引:4,自引:2,他引:2
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I Van Die M Wauben I Van Megen H Bergmans N Riegman W Hoekstra P Pouwels B Enger-Valk 《Journal of bacteriology》1988,170(12):5870-5876
The influence of genetic manipulation of the structural genes coding for major P-fimbrial subunits on the formation of fimbriae in Escherichia coli was studied. Deletion of two regions that code for hypervariable parts of the P fimbrillin resulted in strong reduction or total absence of fimbria production. Replacement of deleted amino acids by other amino acid residues restored the formation of fimbriae. The hypervariable regions may be important for biogenesis of fimbriae by imposing correct spacing between conserved regions of the protein. The potential for substituting amino acids in the P-fimbrial subunit opens interesting possibilities for use of fimbriae as carriers of foreign antigenic determinants. An antigenic determinant of foot-and-mouth disease virus (FMDV) was incorporated in the F11 fimbrial subunit. Hybrid fimbriae, recognized by an FMDV-specific neutralizing monoclonal antibody directed against FMDV, were formed. 相似文献
60.
Mohamed M Thabet Thomas WJ Huizinga Désirée M van der Heijde Annette HM van der Helm-van Mil 《Arthritis research & therapy》2009,11(5):1-9