Immuno-cytochemical localization of glycoproteins involved in recognition and attachment in a mycoparatism

Polyclonal antibodies prepared against the two glycoproteins (Mr 100 and 85 kDa) involved in recognition and attachment of the mycoparasite, Piptocephalis virginiana, to its hosts, Mortierella pusilla and Phascolomyces articulosus, susceptible and resistant, respectively, were employed to localize the antigens at their cell surfaces. Indirect immunocytochemical technique using secondary antibodies labelled with either FITC or gold particles as probes, were used. FITC-Iabelled antibodies revealed a discontinous pattern of fluorescence on the hyphae of MortlerelLa pusilla and no fluorescence on the hyphae of Phascolomyces articulosus. Intensity of fluorescence was high in the germinating spores of both the fungi. Fluoresence could be observed on P. articulosus hyphae pretreated with a commercial proteinase. Fluorescence was not observed on either hyphae or germinating spores of the nonhost M0 r tie re11 a ca ndelabrum and the mycoparasite P. virginiana. Antibodies labelled with gold conjugate showed a different pattern of antigen localization on the hyphal walls of the susceptible and resistant hosts. Patches of gold particles were observed allover the whole cell wall of the susceptible host but only on the inner cell wall layer of the resistant host. Cell wall fragments of the susceptible host but not those of the resistant host, previously incubated with the antibodies inhibited attachment of the mycoparasite. Implications of preferential localization of the antigen in the resistant host and its absence in the nonhost are described

SHP-1 Associates with Both Platelet-derived Growth Factor Receptor and the p85 Subunit of Phosphatidylinositol 3-Kinase*

The Src homology 2 (SH2)-containing protein tyrosine phosphatase 1, SHP-1, is highly expressed in all hematopoietic cells as well as in many non-hematopoietic cells, particularly in some malignant epithelial cell lines. In hematopoietic cells, SHP-1 negatively regulates multiple cytokine receptor pathways. The precise function and the targets of SHP-1 in non-hematopoietic cells, however, are largely unknown. Here we demonstrate that SHP-1 associates with both the tyrosine-phosphorylated platelet-derived growth factor (PDGF) receptor and the p85 subunit of phosphatidylinositol 3-kinase in MCF-7 and TRMP cells. Through the use of mutant PDGF receptors and performing peptide competition for immunoprecipitation, it was determined that SHP-1 independently associates with the PDGF receptor and p85 and that its N-terminal SH2 domain is directly responsible for the interactions. Overexpression of SHP-1 in TRMP cells transfected with the PDGF receptor markedly inhibited PDGF-induced c-fos promoter activation, whereas the expression of three catalytically inactive SHP-1 mutants increased the c-fos promoter activation in response to PDGF stimulation. These results indicate that SHP-1 might negatively regulate PDGF receptor-mediated signaling in these cells. Identification of the association of SHP-1 with the PDGF receptor and p85 in MCF-7 and TRMP cells furthers our understanding of the function of SHP-1 in non-hematopoietic cells

Method of Tower-less Calibration for Phase Parameter of Tracking System

This paper introduced the principle of angle errors in tracking system. The demodulation was only related to signal envelop, and supported the phase calibration of radio star. And this paper which is combined with the commonly-used phase calibration methods, carried out the phase calibration of radio star and the satellite on the specific device, summarized the procedure of radio star for phase calibration and compared the accuracy of it. On the basis of analyzing the theory of phase calibration, the authors concluded the relationship between the parameter of phase calibration and the working frequency. Through utilizing the results of satellite phase calibration to verification and the results of phase calibration of radio star on full-band, and achieving the parameter of phase calibration without the calibration tower, it has a good engineering practice value

Method of Tower-less Calibration for Phase Parameter of Tracking System

This paper introduced the principle of angle errors in tracking system. The demodulation was only related to signal envelop, and supported the phase calibration of radio star. And this paper which is combined with the commonly-used phase calibration methods, carried out the phase calibration of radio star and the satellite on the specific device, summarized the procedure of radio star for phase calibration and compared the accuracy of it. On the basis of analyzing the theory of phase calibration, the authors concluded the relationship between the parameter of phase calibration and the working frequency. Through utilizing the results of satellite phase calibration to verification and the results of phase calibration of radio star on full-band, and achieving the parameter of phase calibration without the calibration tower, it has a good engineering practice value

SHP-1 associates with both platelet-derived growth factor receptor and the p85 subunit of phosphatidylinositol 3-kinase

UI - 98123150NRC publication: Ye

Positive effect of overexpressed protein-tyrosine phosphatase PTP1C on mitogen-activated signaling in 293 cells

NRC publication: Ye