Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Urea has been used to remove the S1 spike glycopolypeptide from avian infectious bronchitis virus (IBV) strains M41 and Beaudette, without removing the S2 spike-anchoring glycopolypeptide. Reduction of the pH to 2.9 did not cause release of S1 although some S1 was released spontaneously from IBV Beaudette at pH 7.4. Virus that lacked S1 was no longer infectious or able to cause haemagglutination (HA). However, radiolabelled IBV that lacked S1 attached to erythrocytes and chick kidney cells to the same or similar extent as did intact virus. Treatment of IBV with a phospholipase C preparation, required to make IBV cause HA, did not increase binding of IBV to erythrocytes. The results indicate that while the attachment to cells of virus that lacks S1 is qualitatively different from that of intact virus, the decline in infectivity is the consequence of the loss of some other spike function.
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PMID:Coronavirus IBV: removal of spike glycopolypeptide S1 by urea abolishes infectivity and haemagglutination but not attachment to cells. 301 54

Sensitivity of the Beaudette strain of infectious bronchitis virus (IBV) to non-antibody inhibitors in neutralization tests depended on the passage history of the virus. The chick embryo kidney cell-adapted (E71 CEK11) virus was the most sensitive, but after one chick embryo (CE) passage (E71 CEK11 E1), this virus showed reversion to the sensitivity of the parent virus (E71). IBV inhibitors in chicken serum could be removed by treatment with trypsin but not with phospholipase C.
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PMID:Effect of different passage histories of infectious bronchitis virus on the sensitivity to inhibitors in chick serum and their removal by trypsin. 614 98

The hemagglutination-inhibition (HI) test was evaluated as a method of typing recent suspect infectious bronchitis virus (IBV) isolates. Hemagglutination (HA) antigen was prepared from each isolate by phospholipase C treatment of virus concentrated from allanto-amniotic fluids of infected chicken embryos. An HI test was run with the HA antigen of each isolate against a battery of 17 antisera that had been prepared against different IBV strains classified by virus neutralization (VN). The HI test identified Ark 99 and Holland isolates that were similar to strains previously classified by VN. Two isolates included in this study were not inhibited by any of the reference antisera and therefore appeared to be antigenically different. The isolates were also evaluated by VN, and the results of the VN and HI methods agreed. Therefore the results suggest that the HI test can be useful for making a rapid, presumptive identification of new IBV isolates.
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PMID:Rapid serotyping of infectious bronchitis virus isolates with the hemagglutination-inhibition test. 620 9

A total of 166 infectious bronchitis virus (IBV) hemagglutination (HA) antigen preparations were made during a 30-month period from allanto-amnionic fluid (AAF) from chicken embryos inoculated with 10 different IBV strains (Mass 41, Conn 46, H52, Florida 18288, Ark 99, JMK, T, Holte, EF, SE17). Antigens were prepared by inoculating 9- or 10-day-old embryos with 10(5.0) to 10(6.5) EID50 IBV, harvesting AAF after a 30-hour-postinoculation incubation, and phospholipase C (PLC) treatment of virus concentrated by pelleting from the AAF. Longer (48 hr) incubation times were tried, but production of H52 HA antigen was successful only from AAF harvested after 30 hours of incubation. AAF from JMK-infected embryos had lower infectivity titers and frequently yielded lower HA antigen titers than the other strains. The treatment of AAF with fluorocarbon did not enhance or diminish HA activity but did yield clearer antigens by removing extraneous material. Polyethylene glycol precipitation of virus was an acceptable alternative to pelleting virus at 39,000 X g. Inactivation of IBV with 0.1% betapropiolactone did not affect HA activity, whereas inactivation with 0.1% formalin caused a marked reduction in HA titer. Different buffer formulations including phosphate, tris, or HEPES were tried to optimize the conditions for PLC treatment of virus concentrate, but there were no apparent differences in the antigens prepared in the different buffers. The HA antigen preparations were stored and were stable at 4 C. Antigen titers of greater than or equal to 64 after storage for 20 months or longer were not uncommon. Addition of merthiolate as a preservative had no deleterious effect on HA activity. Antigen stability appeared to be enhanced by incorporating EDTA in buffer for virus pellet recovery and during enzyme treatment. Attempts to produce HA antigens from cell-culture-adapted virus propagated in chicken kidney cells were less satisfactory. An acceptable HA antigen was prepared from only two (Mass 41, SE17) of the seven strains that were tried. Virus propagation in chicken embryos is the better method of the two for IBV HA antigen production. Aside from the need to concentrate virus and treat the concentrate with PLC, there appeared to be considerable latitude in the procedures that can be used to make acceptable IBV HA antigens.
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PMID:Observations on the preparation and stability of infectious bronchitis virus hemagglutination antigen from virus propagated in chicken embryos and chicken kidney cell cultures. 633 66

Protease-activated receptors (PARs) are widely distributed in human airways. They couple to G- proteins and are activated after proteolytic cleavage of the N terminus of the receptor. Evidence is growing that PAR subtype 2 plays a pivotal role in inflammatory airway diseases, such as allergic asthma or bronchitis. However, nothing is known about the effects of PAR-2 on electrolyte transport in the native airways. PAR-2 is expressed in airway epithelial cells, where they are activated by mast cell tryptase, neutrophil proteinase 3, or trypsin. Recent studies produced conflicting results about the functional consequence of PAR-2 stimulation. Here we report that stimulation of PAR-2 receptors in mouse and human airways leads to a change in electrolyte transport and a shift from absorption to secretion. Although PAR-2 appears to be expressed on both sides of the epithelium, only basolateral stimulation results in inhibition of amiloride sensitive Na+ conductance and stimulation of both luminal Cl- channels and basolateral K+ channels. The present data indicate that these changes occur through activation of phospholipase C and increase in intracellular Ca2+, which activates basolateral SK4 K+ channels and luminal Ca2+-dependent Cl- channels. In addition, the present data suggest a PAR-2 mediated release of prostaglandin E2, which may contribute to the secretory response. In conclusion, these results provide further evidence for a role of PAR-2 in inflammatory airway disease: stimulation of these receptors may cause accumulation of airway surface liquid, which, however, may help to flush noxious stimuli away from the affected airways.
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PMID:Control of ion transport in mammalian airways by protease activated receptors type 2 (PAR-2). 1580 58

This study was conducted to investigate the incidence of infectious bronchitis virus (IBV) in commercial broiler and layer flocks in Pakistan. Serum samples from 16 layers and 9 broiler flocks were screened against M-41, D-274, D-1466, and 4-91 strain antigens using hemagglutination inhibition assay. Overall, 88% of the flocks were seropositive for M-41 antibodies, whereas 40, 52, and 8% of the flocks were positive for D-274, D-1466, and 4-91 IBV strains, respectively. The M-41 antigen was also detected in lungs and tracheal tissues of the clinically positive infectious bronchitis cases. Phospholipase C treatment of the lung and tracheal tissue homogenates from IBV-positive chickens increased the detection limit for M-41 strain from 1.3% positive samples in simple hemagglutination assay to 30.6% positivity when the same samples were treated with phospholipase C. Similarly, reverse transcription-PCR was a much better M-41 detection tool as compared with the classical agar gel precipitation assay utilized to screen tissue homogenates from IBV-positive chickens. In conclusion, this survey clearly demonstrates that several strains of IBV are prevalent in poultry flocks in Pakistan. By utilizing such diagnostic techniques it is possible to conduct a detailed epidemiological study to determine the full economic impact of this disease.
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PMID:Detection and seroprevalence of infectious bronchitis virus strains in commercial poultry in Pakistan. 1757 79

Four of the 9 strains of infectious bronchitis virus which were concentrated and treated with phospholipase C type 1 showed haemagglutination activity. These strains, Holte, Massachusetts 41 (M41), H120 and Connecticut, were distinguishable by the haemagglutination inhibition (HI) test but showed much closer relationships than could be detected by the plaque reduction (PR) test. The four haemagglutinating strains were used to compare the HI and PR titres of 17 anti sera prepared against reference and field virus strains. In most cases titres were similar although there was a tendency for the HI titres to be higher than the PR titres especially with M41 antigen. HI titrations of the pooled sera from 20 birds infected with M41 showed a peak of activity at 14 days after infection which was not detected by serum neutralisation or complement fixation tests. HI titres of individual sera from birds infected 21 days previously with M41 virus compared favourably with serum neutralisation titres but showed little relationship to the complement fixation titres.
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PMID:Preliminary evaluation of the haemagglutination and haemagglutination inhibition tests for avian infectious bronchitis virus. 1877 37