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1.
Epidermal-growth-factor-stimulated phosphorylation of calpactin II in membrane vesicles shed from cultured A-431 cells. 总被引:2,自引:1,他引:1
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Membrane vesicles shed from intact A-431 epidermoid carcinoma cells and harvested in the presence of Ca2+ contained epidermal-growth-factor (EGF) receptor/kinase substrates of apparent molecular masses 185, 85, 70, 55, 38 and 27 kDa. The 38 kDa substrate (p38) was recognized by an antibody that had been raised against the human placental EGF receptor/kinase substrate calpactin II (lipocortin I). The A-431 and placental substrates, isolated by immunoprecipitation after phosphorylation in situ, yielded identical phosphopeptide maps upon limited proteolytic digestion with each of five different enzymes. The A-431-cell vesicular p38 is therefore calpactin II. EGF treatment of the intact A-431 cells before inducing vesiculation was not necessary for the substrate to be present within the vesicles. Our data thus indicate that receptor internalization is not a prerequisite for receptor-mediated phosphorylation of calpactin II. The ability of the protein to function as a substrate for the receptor/kinase depended upon the continued presence of Ca2+ during the vesicle-isolation procedure. EGF-stimulated phosphorylation of calpactin II was much less pronounced in vesicles prepared from A-431 cells in the absence of Ca2+, although comparable amounts of the protein were detectable by immunoblotting. Calpactin II therefore appears to be sequestered in a Ca2+-modulated manner within shed vesicles, along with at least four other major targets for the EGF receptor/kinase. The vesicle preparation may be a useful model system in which to study the phosphorylation and function of potentially important membrane-associated substrates for the receptor. 相似文献
2.
M Favrot R Capdeville V Combaret D C Zhou G Clapisson J Banchereau C R Franks S Chouaib J Y Blay T Philip 《European cytokine network》1990,1(3):141-147
The effect of human IL-4, used as a single agent or in combination with low or high dose IL-2, upon LAK-cell proliferation and activation has been tested on PBMC from patients treated with alpha 2-IFN and IL-2. Four days in vitro culture with IL-4 did not induce any LAK-cell activation; IL-4 induced the proliferation of CD3+ CD4+ T-cells, but decreased the percentage of NK cells in culture samples. When combined with high dose IL-2, IL-4 improved the recovery of MN cell without modification of T-cell subsets; however, IL-4 had no major effect on IL-2-induced NK or LAK cell activity. The combination of IL-4 and low dose IL-2 still significantly improved the total MN cell recovery but did not modify the distribution of T and NK lymphocytes; IL-4 inhibited low dose IL-2-induced NK and LAK cell activity, and increased the BL-esterase activity induced by high or low dose IL-2. The combination of IL-4 and IL-2 did not induce any large variation in the percentage of IL-2R (p55) expressing cells. In all tested conditions, IL-2R (p55) was mainly expressed on CD4+ T cells; less than 2% of the cells coexpressed the NK cell marker CD56 and IL-2R (p55). The effect of IL-4 upon IL-2-induced LAK cell expansion is thus very different on PBMC pre-activated in vivo by alpha IFN + IL-2 therapy than on PBMC pre-treated in vitro with IL-2.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
Ramana M. Gosukonda Ananta Porobodessai Essie Blay Channapatna S. Prakash Curt M. Peterson 《In vitro cellular & developmental biology. Plant》1995,31(2):65-71
Adventitious shoots of sweetpotato (Ipomoea batatas L. Lam.) were produced in vitro using a two-stage culture method. Petiole explants were incubated on Murashige and Skoog
(MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (0.2 mg·liter−1) for 3 d, and transferred to MS medium with thidiazuron (0 to 0.4 mg·liter−1). Shoot regeneration was observed in most explants (78.2%) of genotype PI 318846-3 within 28 days when cultured on thidiazuron
at 0.2 mg·liter−1. Histological studies of cultured petiole explants showed meristematic activity within cells of vascular bundles and throughout
the ground tissue. Explants isolated from apical leaves exhibited higher shoot regeneration frequency than those isolated
from the basal portion of the shoot. Leaf lamina explants exhibited lower frequency of regeneration than petiole explants.
In contrast to thidiazuron, the use of zeatin riboside, and kinetin resulted in a lower frequency of shoot regeneration although
more sweetpotato genotypes could be regenerated using either of these two cytokinins. The sweetpotato plants regenerated using
thidiazuron grew vigorously and rooted easily when transferred to the greenhouse. 相似文献
4.
Molecular characterization of mouse-virulent poliovirus type 1 Mahoney mutants: involvement of residues of polypeptides VP1 and VP2 located on the inner surface of the capsid protein shell. 总被引:13,自引:12,他引:1
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Most poliovirus (PV) strains, including PV PV-1/Mahoney, are unable to cause paralysis in mice. Determinants for restriction of PV-1/Mahoney in mice have been identified by manipulating PV-1 cDNA and located on the viral capsid protein VP1. These determinants consist of a highly exposed amino acid sequence on the capsid surface corresponding to the B-C loop (M. Murray, J. Bradley, X. Yang, E. Wimmer, E. Moss, and V. Racaniello, Science 241:213-215, 1988; A. Martin, C. Wychowski, T. Couderc, R. Crainic, J. Hogle, and M. Girard, EMBO J. 7:2839-2847, 1988) and of residues belonging to the N-terminal sequence located on the inner surface of the protein shell (E. Moss and V. Racaniello, EMBO J. 10:1067-1074, 1991). Using an in vivo approach, we isolated two mouse-neurovirulent PV-1 mutants in the mouse central nervous system after a single passage of PV-1/Mahoney inoculated by the intracerebral route. Both mutants were subjected to two additional passages in mice, plaque purified, and subsequently characterized. The two cloned mutants, Mah-NK13 and Mah-NL32, retained phenotypic characteristics of the parental PV-1/Mahoney, including epitope map, heat lability, and temperature sensitivity. Mah-NK13 exhibited slightly smaller plaques than did the parental virus. The nucleotide sequences of the mutant genomes were determined, and mutations were identified. Mutations were independently introduced into the parental PV-1/Mahoney genome by single-site mutagenesis. Mutated PV-1/Mahoney viruses were then tested for their neurovirulence in mice. A single amino acid substitution in the capsid proteins VP1 (Thr-22-->Ile) and VP2 (Ser-31-->Thr) identified in the Mah-NK13 and Mah-NL32 genomes, respectively, conferred the mouse-virulent phenotype to the mouse-avirulent PV-1/Mahoney. Ile-22 in VP1 was responsible for the small-plaque phenotype of Mah-NK13. Both mutations arose during the first passage in the mouse central nervous system. We thus identified a new mouse adaptation determinant on capsid protein VP1, and we showed that at least one other capsid protein, VP2, could also express a mouse adaptation determinant. Both determinants are located in the inside of the three-dimensional structure of the viral capsid. They may be involved in the early steps of mouse nerve cell infection subsequent to receptor attachment. 相似文献
5.
Abstract. Variation of soil matric potential of a Wet Evergreen and a Moist Semi-deciduous West African forest were compared. The two forest types differed strongly in their soil water regime. Wet Evergreen forest experienced matric potentials below ?100 kPa only occasionally, while in Moist Semi-deciduous forest matric potentials were less than ?2.5 MPa for periods of several weeks or more each season. A water balance equation was used to simulate the soil water regime at both sites and predict severity and length of the dry period. The predictions showed good agreement with the field measurements of soil water potential over a 2-yr period. The methodology was used to estimate the occurrence and severity of droughts over longer periods at the two sites. The balance calculations suggest that droughts occur occasionally in the Wet Evergreen forest under study. The potential impact of droughts on species distribution and vegetation disturbance in tropical forests is discussed. 相似文献
6.
An efficient system for Agrobacterium tumefaciens-mediated transformation of Solanum gilo was established. The marker genes for kanamycin resistance and ß-glucuronidase expression were introduced. A comparison between cotyledon and hypocotyl explants showed that while regeneration was better from hypocotyl explants, cotyledon explants gave better transformation efficiency (46% vs. 32%). Four levels of kanamycin selection (100, 150, 200 and 250 mg/l) were tested for effect on transformation efficiency with each type of explant. Lower levels of kanamycin worked better using cotyledon explants, while higher levels of kanamycin worked better for hypocotyl explants. All nine t0 plants tested for expression of the kan
r
gene were positive. The progeny of three of these plants showed a pattern of classical Mendelian inheritance (3 to 1) for both the kan
r
and the ß-glucuronidase genes.Abbreviations MS
Murashige and Skoog (1962) medium
- 2,4-D
2,4-Dichlorophenoxyacetic acid
- NPTII
neomycin phosphotransferase
- GUS
ß-glucuronidase 相似文献
7.
J. Badel C. Desuzinges S. Rey S. Baconnier D. Perol G. Garin P. Cassier J. Blay Y. Nakamura C. Fukukawa T. Mognetti 《Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)》2013
8.
Wendy Blay Puryear Hisashi Akiyama Suzanne D. Geer Nora P. Ramirez Xinwei Yu Bj?rn M. Reinhard Suryaram Gummuluru 《PLoS pathogens》2013,9(4)
Human immunodeficiency virus type 1 (HIV-1) interactions with myeloid dendritic cells (DCs) can result in virus dissemination to CD4+ T cells via a trans infection pathway dependent on virion incorporation of the host cell derived glycosphingolipid (GSL), GM3. The mechanism of DC-mediated trans infection is extremely efficacious and can result in infection of multiple CD4+ T cells as these cells make exploratory contacts on the DC surface. While it has long been appreciated that activation of DCs with ligands that induce type I IFN signaling pathway dramatically enhances DC-mediated T cell trans infection, the mechanism by which this occurs has remained unclear until now. Here, we demonstrate that the type I IFN-inducible Siglec-1, CD169, is the DC receptor that captures HIV in a GM3-dependent manner. Selective downregulation of CD169 expression, neutralizing CD169 function, or depletion of GSLs from virions, abrogated DC-mediated HIV-1 capture and trans infection, while exogenous expression of CD169 in receptor-naïve cells rescued GSL-dependent capture and trans infection. HIV-1 particles co-localized with CD169 on DC surface immediately following capture and subsequently within non-lysosomal compartments that redistributed to the DC – T cell infectious synapses upon initiation of T cell contact. Together, these findings describe a novel mechanism of pathogen parasitization of host encoded cellular recognition machinery (GM3 – CD169 interaction) for DC-dependent HIV dissemination. 相似文献
9.
Jordi Valls-Margarit Ivn Galvn-Femenía Daniel Matías-Snchez Natalia Blay Montserrat Puiggrs Anna Carreras Cecilia Salvoro Beatriz Corts Ramon Amela Xavier Farre Jon Lerga-Jaso Marta Puig Jose
Francisco Snchez-Herrero Victor Moreno Manuel Perucho Lauro Sumoy Lluís Armengol Olivier Delaneau Mario Cceres Rafael de
Cid David Torrents 《Nucleic acids research》2022,50(5):2464
The combined analysis of haplotype panels with phenotype clinical cohorts is a common approach to explore the genetic architecture of human diseases. However, genetic studies are mainly based on single nucleotide variants (SNVs) and small insertions and deletions (indels). Here, we contribute to fill this gap by generating a dense haplotype map focused on the identification, characterization, and phasing of structural variants (SVs). By integrating multiple variant identification methods and Logistic Regression Models (LRMs), we present a catalogue of 35 431 441 variants, including 89 178 SVs (≥50 bp), 30 325 064 SNVs and 5 017 199 indels, across 785 Illumina high coverage (30x) whole-genomes from the Iberian GCAT Cohort, containing a median of 3.52M SNVs, 606 336 indels and 6393 SVs per individual. The haplotype panel is able to impute up to 14 360 728 SNVs/indels and 23 179 SVs, showing a 2.7-fold increase for SVs compared with available genetic variation panels. The value of this panel for SVs analysis is shown through an imputed rare Alu element located in a new locus associated with Mononeuritis of lower limb, a rare neuromuscular disease. This study represents the first deep characterization of genetic variation within the Iberian population and the first operational haplotype panel to systematically include the SVs into genome-wide genetic studies. 相似文献
10.
Adult Zucker lean (Fa/?) female rats received a single 250 nmol oral gavage of 3H-labelled oleoylestrone in 0.2 ml of sunflower oil. After one hour, samples of arterial, portal and suprahepatic blood, and lymph were obtained and fractioned to determine the amount of radioactivity present in the form of free estrone, acyl-estrone and hydrophilic estrone esters in the blood of each vessel. Lipoprotein fractions (chylomicra + VLDL, LDL, HDL and lipoprotein-depleted plasma) were also analysed as well as the distribution of absorbed 3H-estrone in the intestine, specific organs and carcass. About one third of the oleoyl-estrone dose recovered was found in the tissues, mainly in the blood, the rest remaining relatively untouched in the intestinal content. High hypothalamic estrone uptake (compared with the rest of the brain) was observed. Data from non-radioactive estrone measurements showed a similar pattern of absorption and tissue distribution to that obtained by 3H-estrone tracking alone. In both cases, most of the estrone present in the intestinal lumen was absorbed as intact oleoyl-estrone, but a significant part was absorbed as free estrone. There is a net transfer of 3H-estrone into portal blood HDL, and part of the 3H-estrone is also loaded into lymph-carried chylomicra. A large share of free estrone is filtered by the liver, but most of the acyl-estrone absorbed passes unaltered. The oral administration of oleoyl-estrone results in significant absorption of the unaltered molecule, which is transferred to lymph-carried chylomicra and also directly to plasma HDLs. It may be inferred that the HDL fraction contains the physiological carrier of oleoyl-estrone in its role of ponderostat signal. 相似文献