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81.
82.
Three human cell lines used in human immunodeficiency virus research were found to be contaminated with previously undetected retroviruses. On the bases of partial nucleotide sequence, capsid protein antigenicity, vector mobilization, and receptor usage studies, these contaminants were shown to be replication competent and to belong to the Gammaretrovirus genus. While the TZM-bl cells harbor ecotropic murine leukemia virus (MLV), Jurkat J6 cells were found to release xenotropic MLV and the A3.01/F7 cells to produce gibbon ape leukemia virus. These findings highlight the importance of routine testing of cell lines for retrovirus contamination to prevent potential experimental artifacts and allow correct biohazard assessment. 相似文献
83.
Kaposi's sarcoma-associated herpes virus (KSHV), the causative agent of several neoplasms, has recently been shown to encode 12 microRNAs. mir-155 is a host-encoded microRNA associated with lymphomagenesis. Two new papers provide strong evidence that a KSHV-encoded microRNA and mir-155 share a common set of mRNA targets and binding sites, implying a possible link between viral- and non-viral-mediated tumorigenesis. 相似文献
84.
85.
A screen for genes that function in leg disc regeneration in Drosophila melanogaster 总被引:1,自引:0,他引:1
Many diverse animal species regenerate parts of an organ or tissue after injury. However, the molecules responsible for the regenerative growth remain largely unknown. The screen reported here aimed to identify genes that function in regeneration and the transdetermination events closely associated with imaginal disc regeneration using Drosophila melanogaster. We screened a collection of 97 recessive lethal P-lacZ enhancer trap lines for two primary criteria: first, the ability to dominantly modify wg-induced leg-to-wing transdetermination and second, for the activation or repression of the lacZ reporter gene in the blastema during disc regeneration. Of the 97 P-lacZ lines, we identified six genes (Krüppel-homolog-1, rpd3, jing, combgap, Aly and S6 kinase) that met both criteria. Five of these genes suppress, while one enhances, leg-to-wing transdetermination and therefore affects disc regeneration. Two of the genes, jing and rpd3, function in concert with chromatin remodeling proteins of the Polycomb Group (PcG) and trithorax Group (trxG) genes during Drosophila development, thus linking chromatin remodeling with the process of regeneration. 相似文献
86.
Chong Jiang Sheena F. McClure Robert W. Stoddart John McClure 《Glycoconjugate journal》2003,20(6):367-374
Information about the saccharides expressed in gastric mucosa is mostly limited to the glycan content of gastric mucins and
there are only a few studies of the glycoprofiling of the constituent cells and their components. Knowledge of the glycan
expression of normal gastric mucosa is necessary for the interpretation of the significance of changes of expression in disease.
A lectin histochemical study of normal human gastric (body) mucosa was performed using 27 lectins chosen to probe for a wide
range of oligosaccharide sequences within several categories of glycoprotein glycans.
There were marked differences in staining reactions in the various microanatomical structures of the mucosa, particularly
between pits and glands with the former more closely resembling the surface epithelium. A notable feature was the degree of
difference in the staining between a substantial sub-population of cells within the neck region and the epithelium of both
the pits and glands. These neck cells resembled the pit cells with some lectins, glandular cells with some others and neither
with some other lectins. Overall, the differences between the pit, gland and neck epithelia were diverse and numerous, and
could not be explained by altered activity of a small set of glycosyltransferases. Widespread alterations of glycans must
have occurred (affecting terminal and internal parts of their structures) and the very different glycotypes of the pit, neck
and gland epithelia are, therefore, suggestive of the existence of three cell lineages within normal gastric epithelium. Published in 2004.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
87.
Michael J. McClure Scott A. Sell David G. Simpson Beat H. Walpoth Gary L. Bowlin 《Journal of visualized experiments : JoVE》2011,(47)
Throughout native artery, collagen and elastin play an important role, providing a mechanical backbone, preventing vessel rupture, and promoting recovery under pulsatile deformations. The goal of this study was to mimic the structure of native artery by fabricating a multi-layered electrospun conduit composed of poly(caprolactone) (PCL) with the addition of elastin and collagen with blends of 45-45-10, 55-35-10, and 65-25-10 PCL-ELAS-COL to demonstrate mechanical properties indicative of native arterial tissue, while remaining conducive to tissue regeneration. Whole grafts and individual layers were analyzed using uniaxial tensile testing, dynamic compliance, suture retention, and burst strength. Compliance results revealed that changes to the middle/medial layer changed overall graft behavior with whole graft compliance values ranging from 0.8 - 2.8 % / 100 mmHg, while uniaxial results demonstrated an average modulus range of 2.0 - 11.8 MPa. Both modulus and compliance data displayed values within the range of native artery. Mathematical modeling was implemented to show how changes in layer stiffness affect the overall circumferential wall stress, and as a design aid to achieve the best mechanical combination of materials. Overall, the results indicated that a graft can be designed to mimic a tri-layered structure by altering layer properties. 相似文献
88.
M. J. Gravato-Nobre M. A. McClure L. Dolan G. Calder K. G. Davies B. Mulligan K. Evans N. von Mende 《Journal of nematology》1999,31(2):212-223
Surface-coat epitopes of Meloidogyne incognita were detected in root tissues of Arabidopsis thaliana during migration and feeding site formation. A whole-mount root technique was used for immunolocalization of surface coat epitopes in A. thaliana, with the aid of a monoclonal antibody raised specifically against the outer surface of infective juveniles of M. incognita. The antibody, which was Meloidogyne-specific, recognized a fucosyl-bearing glycoprotein in the surface coat. During migration in host tissues the surface coat was shed, initially accumulating in the intercellular spaces next to the juvenile and later at cell junctions farther from the nematode. Upon induction of giant cell formation, the antibody bound to proximally located companion cells and sieve elements of the phloem. 相似文献
89.
90.
J. A. MacDiarmid R. Clarke S. J. McClure F. R. Bowen D. H. Burrell 《International journal for parasitology》1995,25(12):1505-1507
A new monoclonal raised against sheep IgE was used to examine sera and wound exudates from sheep which had been struck by Lucilia cuprina in the field. The antibody was also used to detect the presence of IgE in sera and skin sections from sheep which had been artificially infected with fly larvae 3 times. Neither total, nor L. cuprina specific circulating IgE could be detected in serum or wound exudates from struck sheep. Cell bound IgE was, however, identified by the monoclonal in skin sections from struck sheep and from a control sheep which had not been struck. No difference in the number of IgE positive cells was observed between the control and 2 of the 3 artificially infected sheep, and none of the latter showed an increase in IgE positive cells even after 3 infections. One sheep showed twice as many IgE positive cells as the other treated sheep and the third larval infection was difficult to establish and limited in size and severity. This suggests a relationship between innate resistance to strike and the number of IgE positive cells present in skin. 相似文献