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51.
It has previously been shown that of all the soluble reovirus-specified proteins present in the infected cell lysate, protein sigma 1 alone possesses the capacity to bind to host cells (P.W.K. Lee, E.C. Hayes, and W.K. Joklik, 1981, Virology 108, 156-163). We found that sigma 1 from urea-disrupted reovirus particles was also capable of such specific binding. Reovirions were therefore used as a source of functional sigma 1. Accordingly, a simple procedure has been developed to purify sigma 1 by subjecting urea-disrupted reovirions to DEAE ion-exchange chromatography. Protein sigma 1 thus isolated was electrophoretically homogeneous and the recovery was estimated to be 50 to 60% of the theoretical yield. The purified protein presumably maintained its native conformation since it was recognized by a panel of monoclonal anti-sigma 1 antibodies previously isolated, and was capable of specifically binding to host cell receptors, agglutinating human erythrocytes and inducing neutralization and hemagglutination-inhibition antibodies. Subsequent chemical crosslinking studies revealed the presence of oligomeric (mostly dimeric) sigma 1 forms in the preparation. The amino acid composition of the purified sigma 1 was found to closely match that inferred from the S1 gene sequence. However, attempts to determine its amino-terminal sequence have not been successful. The p/ of the purified protein was determined to be 6.8. Circular dichroic measurements of the purified sigma 1 indicated that 54 and 19% of its residues were arranged in alpha-helical and beta-sheet secondary structures, respectively. 相似文献
52.
A delayed hypersensitivity (DH) reaction is induced by a sensitizing intradermal injection of methylated bovine serum albumin (MBSA) into the abdomen of mice and a subsequent challenge injection of MBSA into the hind paw. Paw volume increase is measured by mercury plethysmography. The conditions for sensitization have been investigated. Sensitization with a 0.25% MBSA emulsion resulted in a small but significant swelling of the paw following the challenge injection. The magnitude of the footpad response to the challenge injection was increased if the antigen administered in the sensitizing injection was emulsified with Freund's incomplete adjuvant. Incorporation ofMycobacterium butyricum in the emulsion greatly increased the footpad response if added at doses of 0.05 and 1 mg per animal. A higher dose (4 mg), however, resulted in a lower response. The time course of development of the delayed hypersensitivity reaction has been studied. An 8-day interval between sensitization and challenge resulted in a greater delayed hypersensitivity response than a shorter (3-day) or longer (15-, 21-, 28-day) interval. Cyclophosphamide (250 mg kg–1) administered 3 days prior to the sensitizing injection of MBSA produced a modest enhancement of the DH reaction.On the basis of these studies a protocol for conducting the DH reaction to MBSA was established and the activity of drugs on processes underlying the sensitization phase of the reaction or processes underlying the elicitation phase of the reaction have been examined. Steroid and immunosuppressant drugs were found to inhibit the DH footpad response when dosed during the sensitization whereas several specific-anti-rheumatic and immunoactive compounds were without effect. Indomethacin and sudoxicam inhibited the DH reaction if dosed during the elicitation of the reaction but other non-steroidal anti-inflammatories tested did not significantly reduce the response. The clinically used anti-rheumatic drugsd-penicillamine and levamisole did not inhibit the elicitation phase of the DH response but niridazole at 100 mg kg–1 did reduce the inflammatory response.This paper has been presented in part as a poster presentation to the British Pharmacological Society, 4–6 January 1978. 相似文献
53.
Relationship between production of epidermal growth factor receptors, gene amplification, and chromosome 7 translocation in variant A431 cells 总被引:1,自引:0,他引:1
G N Gill W Weber D M Thompson C Lin R M Evans M G Rosenfeld S Gamou N Shimizu 《Somatic Cell and Molecular Genetics》1985,11(4):309-318
Synthesis of the epidermal growth factor (EGF) receptor has been analyzed in a series of variant A431 human epidermoid carcinoma cell clones reported to contain different amounts of EGF binding sites. The amount of EGF receptor protein, quantitated by immunoaffinity chromatography, and EGF receptor mRNA, quantitated by cDNA hybridization, were closely correlated to the extent of EGF receptor gene amplification. This correlation existed in variants selected for reduced EGF receptors and in revertants from those variants with increased EGF receptors. There was also a correlation between the frequency of translocation of chromosome 7, containing the EGF receptor gene, and EGF receptor protein. These results support gene amplification as the mechanism enhancing A431 cell EGF receptor protein and determining growth responses. 相似文献
54.
L Kent E Green J Holmes A Thapar M Gill Z Hawi M Fitzgerald P Asherson S Curran J Mills A Payton N Craddock 《American journal of medical genetics》2001,105(8):686-689
Attention-deficit hyperactivity disorder (ADHD) is a highly heritable, common psychiatric disorder of childhood that probably involves several genes. There are several lines of evidence suggesting that the nicotinic system may be functionally significant in ADHD. First, nicotine promotes the release of dopamine and has been shown to improve attention in adults with ADHD, smokers, and nonsmokers. Second, ADHD is a significant risk factor for early initiation of cigarette smoking in children and maternal cigarette smoking appears to be a risk factor for ADHD. Finally, animal studies in rats and monkeys also suggest that nicotine may be involved in attentional systems and locomotor activity. The nicotinic system has previously been studied in schizophrenia where the neuronal nicotinic acetylcholine receptor alpha 7 subunit gene (CHRNA7) has been implicated in decreased P50 inhibition and attentional disturbances in patients with schizophrenia and in many of their nonschizophrenic relatives. Three known microsatellite markers (D15S165, D15S1043, and D15S1360) near the nicotinic acetylcholine alpha 7 receptor gene, CHRNA7, were studied in 206 ADHD parent-proband trios of children aged 5-16 with ADHD according to DSM-IV criteria. Children with known major medical or psychiatric conditions or mental retardation (IQ < 70) were excluded from the study. Markers D15S165 and D15S1360 were in linkage disequilibrium. The extended Transmission Disequilibrium Test analyses demonstrated no evidence that variation at the microsatellite markers D15S1360, D15S1043, and D15S165 influences susceptibility to ADHD. However, it remains possible that the CHRNA7 gene and other nicotinic system genes may be involved in conferring susceptibility to ADHD. 相似文献
55.
Effects of a brisk walk on lipoprotein lipase activity and plasma triglyceride concentrations in the fasted and postprandial states 总被引:3,自引:0,他引:3
This study aimed to determine whether changes in plasma heparin-releasable lipoprotein lipase (LPL) activity following a brisk
walk were associated with decreases in fasting and/or postprandial triglyceride (TG) concentrations. Two groups of pre-menopausal
women participated. In one group (fasting study group, n=10), TG concentrations and post-heparin plasma LPL activity were measured in the fasted state on two occasions: ~18 h after
a 2-h treadmill walk at 50% maximal oxygen uptake (exercise trial); and after a day of no exercise (control trial). The other
group (postprandial study group, n=9) undertook two oral fat tolerance tests (blood samples taken fasting and for 6 h after a high-fat meal), with plasma LPL
activity measured 6 h after meal ingestion. Pre-conditions were the same as for the fasting study group (i.e. control and
prior exercise). Prior exercise reduced fasting TG concentrations by 23 (7)% (fasting study group) [mean (SEM)] and by 18
(9)% (postprandial study group) (both P<0.05), and the postprandial TG response by 23 (6)% (postprandial study group) (P<0.01). Plasma LPL activity was not significantly increased by exercise in either the fasting or postprandial study groups.
However, exercise-induced changes in both fasting and postprandial LPL activity were significantly correlated with the respective
exercise-induced changes in fasting TG concentration and the postprandial TG response (r=−0.70 and −0.77 respectively, P<0.05 for both). These data suggest that increased LPL activity may contribute to the hypotriglyceridaemic effect of moderate
exercise, although other mechanisms are also likely to be involved.
Electronic Publication 相似文献
56.
57.
Katharina Domschke Karen Sheehan Naomi Lowe Aiveen Kirley Celine Mullins Roderick O'sullivan Christine Freitag Tim Becker Judith Conroy Michael Fitzgerald Michael Gill Ziarih Hawi 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2005,(1):110-114
Pharmacological and genetic studies suggest the importance of the dopaminergic, serotonergic, and noradrenergic systems in the pathogenesis of attention deficit hyperactivity disorder (ADHD). Monoamine oxidases A and B (MAO-A and MAO-B) degrade biogenic amines such as dopamine and serotonin and thereby control the levels of these neurotransmitters in the central nervous system. We examined four polymorphisms in the MAO-A gene (30 bp promoter VNTR, CA microsatellite in intron 2, 941G/T SNP in exon 8, and A/G SNP in intron 12) as well as two markers in the MAO-B gene (CA microsatellite in intron 2 and T/C SNP in intron 13) for association with ADHD in an Irish sample of 179 nuclear families. TDT analysis of the examined MAO-A markers revealed a significant association of the more active MAO-A 941G allele with the disorder (chi2 = 5.1, P = 0.03, OR = 1.7). In addition, haplotype analysis revealed a significantly increased transmission of a haplotype consisting of the shorter allele of the promoter VNTR (allele 1), the 6-repeat allele of the CA microsatellite and the G-allele of the 941G/T SNP (famhap global statistic 34.54, P = 0.01) to ADHD cases. No significant distortion in the number of transmitted alleles was observed between the two examined MAO-B polymorphisms and ADHD. These findings suggest the importance of the 941G/T MAO-A polymorphism in the development of ADHD at least in the Irish population. 相似文献
58.
Functional characterization of a sialyltransferase-deficient mutant of Neisseria gonorrhoeae.
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M J Gill D P McQuillen J P van Putten L M Wetzler J Bramley H Crooke N J Parsons J A Cole H Smith 《Infection and immunity》1996,64(8):3374-3378
Previous studies indicate that sialylation of lipopolysaccharide (LPS) by host CMP-N-acetylneuraminic acid (CMP-NANA) catalyzed by bacterial sialyltransferase rendered gonococci resistant to killing by phagocytes, to entry into epithelial cell lines, to killing by immune serum and complement, and to absorption of complement component C3. These results have been confirmed by comparing a sialyltransferase-deficient mutant (strain JB1) with its parent (strain F62) in appropriate tests. In contrast to F62, JB1 was very susceptible to killing by human polymorphonuclear phagocytes in opsonophagocytosis tests and incubation with CMP-NANA did not decrease the level of killing. The inherent resistance of F62 in these tests was probably due to LPS sialylation by CMP-NANA and lactate present in the phagocytes. A JB1 variant expressing the invasion-associated Opa protein was as able to enter Chang human conjunctiva epithelial cells as an Opa-positive variant of F62, suggesting that the sialyltransferase is not required for Opa-mediated entry. After incubation with CMP-NANA, the number of F62 variant gonococci entering cells but not that of JB1 variant gonococci was drastically reduced. Both JB1 and F62 were killed by incubation with rabbit antibody to gonococcal major outer membrane protein, protein I, and human complement, but only F62 was rendered resistant to the killing by incubation with CMP-NANA. Finally, both JB1 and F62 absorbed similar amounts of complement component C3 and the binding was decreased by incubation with CMP-NANA only for the wild type, F62. 相似文献
59.
Detection of Intimins α, β, γ, and δ, Four Intimin Derivatives Expressed by Attaching and Effacing Microbial Pathogens
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Jeannette Adu-Bobie Gad Frankel Christopher Bain Azizedite Guedes Goncalves Luiz R. Trabulsi Gill Douce Stuart Knutton Gordon Dougan 《Journal of clinical microbiology》1998,36(3):662-668
Intimins are outer membrane proteins expressed by enteric bacterial pathogens capable of inducing intestinal attachment-and-effacement lesions. A eukaryotic cell-binding domain is located within a 280-amino-acid (Int280) carboxy terminus of intimin polypeptides. Polyclonal antiserum was raised against Int280 from enteropathogenic Escherichia coli (EPEC) serotypes O127:H6 and O114:H2 (anti-Int280-H6 and anti-Int280-H2, respectively), and Western blot analysis was used to explore the immunological relationship between the intimin polypeptides expressed by different clinical EPEC and enterohemorrhagic E. coli (EHEC) isolates, a rabbit diarrheagenic E. coli strain (RDEC-1), and Citrobacter rodentium. Anti-Int280-H6 serum reacted strongly with some EPEC serotypes, whereas anti-Int280-H2 serum reacted strongly with strains belonging to different EPEC and EHEC serotypes, RDEC-1, and C. rodentium. These observations were confirmed by using purified Int280 in an enzyme-linked immunosorbent assay and by immunogold and immunofluorescence labelling of whole bacterial cells. Some bacterial strains were recognized poorly by either antiserum (e.g., EPEC O86:H34 and EHEC O157:H7). By using PCR primers designed on the basis of the intimin-encoding eae gene sequences of serotype O127:H6, O114:H2, and O86:H34 EPEC and serotype O157:H7 EHEC, we could distinguish between different eae gene derivatives. Accordingly, the different intimin types were designated α, β, δ, and γ, respectively. 相似文献
60.
Modified toluidine blue O stain for Pneumocystis carinii: further evaluation of some technical factors. 总被引:2,自引:0,他引:2
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A modified toluidine blue O (TBO) stain for Pneumocystis carinii cysts was evaluated with regard to the influence of (i) the age and extent of use of the sulfation reagent, (ii) the source of TBO, (iii) the TBO content of the staining solution, and (iv) the amount of TBO present in the alcohol wash solutions. All TBOs evaluated, except for a new TBO obtained from Roboz Surgical Instrument Co., Inc., Washington, D.C., produced satisfactory results. Each lot of TBO should be quality controlled before use to ensure that the P. carinii cysts stain lavender against a blue background. We have ourselves decided to use only certified TBO with a high dye content. As extensively used sulfation reagent provided less satisfactory results than did either freshly prepared or 1-week-old unused sulfation reagent, we have decided to prepare fresh sulfation reagent at least weekly and to discard used sulfation reagent after 10 slides have been processed. 相似文献