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I L Graves

Publications and source records attributed to I L Graves.

25 records · Page 2Linked to original sources
PubMedDate not supplied

Agglutination-separation reactions of red blood cells sensitized with Newcastle disease virus: quantities, agglutination characteristics, and serology of altered virus and HN spikes released following neuraminidase reactivation.

Red blood cells (RBC) become sensitized following the elution of strain 575 Newcastle disease virus (NDV). The neuraminidase (NA) in the haemagglutinin (HA)-sialic acid configuration is inactive. The HA on sensitized RBC agglutinates normal RBC. The sialic acid on normal RBC initiated reactivation of the NA-a newly described function. Then normal-sensitized RBC agglomerates separated at 37 degrees C in the irreversible agglutination-separation (AS) reactions. With separation the AS products. HN spikes (150-200 kDa) and altered NDV, which contain fewer HN spikes than intact allantoic NDV, were removed from the sensitized RBC and the NDV membrane. Extraction of HN spikes from the membrane required more sialic acid than the removal of AS products from RBC. Thus 2 reactions were delineated for the orderly removal. Amounts of each released AS product suggest the source of the HN spikes. AS reactions and ether treatment of NDV increased the HA titres up to 19.2 fold. HA-sialic acid configurations were estimated by the amounts of normal RBC agglutinated by sensitized RBC and also by agglutination with fetuin. Elution of B1 vaccine, HN spikes from ether-treated NDV as well as AS products separated on sephadex resulted in incompletely sensitized RBC; fewer configurations were titrated with normal RBC; all failed to respond to anti-NA antibody. In contrast, sensitized RBC or suspensions of 575 NDV, but not the B1 vaccine strain, responded to both anti-NA and anti-HA antibody. Sensitization, slow elution, and responding to anti-NA antibody, which was accompanied by fluorescent foci on sensitized RBC, required intact NDV and the infrequent HA-sialic acid configuration. The NA was inactive for the HA-sialic acid configuration but cleaved fetuin, indicating substrate specificity. An inactive NA would allow time for fusion and NDV penetration rather than elution by an active NA early in NDV infection.

Animals↗
PubMedDate not supplied

Heat inactivation of the neuraminidase and haemagglutinin estimated in the agglutination-separation reactions using red blood cells sensitized with Newcastle disease virus.

The agglutination-separation (AS) reactions estimate the effects of heat on the release of altered Newcastle disease virus (NDV) and HN glycoprotein spikes from red blood cells (RBC) sensitized with NDV (SRBC), the inactivations of the neuraminidase (NA), then the haemagglutinin (HA) in a direct assay. Heating SRBC for 1.5 min at 56 degrees C inactivated the NA by 50%; after 4.5 min no separation occurred indicating 100% inactivation of the NA. Heating a suspension of NDV for 78 min inactivated the NA 50% as assayed by cleavage of fetuin. Comparatively, the AS test was up to 52-fold (78 min/1.5 min = 52) more efficient in detecting NA inactivation than was the basic reference test where cleavage of fetuin was assayed. The HA was 50% inactivated after 18 min of heating and 100% inactivated after 36 min as no agglutination was seen. Free HA on SRBC was agglutinated by and thus was titrated with the sialic acid on NRBC. The large area of RBC increased the efficiency of the AS test when compared with tests using suspensions of NDV. At 51-60 degrees C all NA and HA inactivations were sequential, and invariably the NA was more heat labile than the HA. The release of altered NDV and HN spikes was inhibited with mild heat although the separation of SRBC and NRBC continued. Biological purifications showed that the heat stability of the HA and the lability of the NA were genetically stable.

Animals↗
PubMedDate not supplied

Influenza viruses in birds of the Atlantic flyway.

Isolation of type A influenza viruses from the feces of 5013 birds of 16 species was attempted during a 33-month study (1977-79). Seventy viruses were isolated from the feces of 3403 ring-billed gulls in Baltimore, Md., during 16 months of sampling. Six hemagglutinin (HA) subtypes and seven neuraminidase (NA) subtypes in 15 combinations were found. The H13N6 virus was the only subtype found each year and accounted for 40% of the isolates. The rate of isolation from gulls was 0.26% in the cold months and 3.0% in the warm months. Hemagglutination-inhibition (HI) and elution-inhibition antibody profiles reflected the presence of some but not all of the viruses isolated. In mute swans, the rates of seroconversions were 16% for HA antibody and 14% for NA antibody, whereas the viral isolation rate was 0.4% over a 3-year period. Both the H5 and the N2 subtypes, which were responsible for the lethal chicken outbreaks in 1983 in Pennsylvania, were isolated from gulls in 1978 in association with subtypes not found in the chicken virus. Also, seroconversions for the H5 HA occurred in mute swans in 1978.

Age Factors↗
PubMedDate not supplied

Aids for in vitro Mycobacterium lepraemurium investigations: estimation of oxidation-reduction potentials and pO2 with 2, 6 dichlorophenol indophenol.

The partial success in cultivating a "host-dependent" microbe provided the incentive to develop methods which may aid the growth of the organism. The oxidation-reduction potential (ORP) of NC-5, an aerobic, cysteine containing medium which supports the limited in vitro growth of Mycobacterium lepraemurium, is measurable with the redox dye, 2, 6 dichlorophenol indophenol. Both cysteine and autoclaved glucose can be used to adjust to ORP. Glucose autoclaved in phosphate buffer but not in aqueous solutions reduced the dye. The dye was also reduced in glucose solutions by atmospheres containing 10% and 1%-2% pO2. With exposure to 20% pO2 the reoxidation of the dye was slow but complete. Thus, the dye in glucose solutions provides a general method for estimating pO2 above the level of anaerobiosis. Proper adjustment and monitoring of the ORP and pO2 may enhance growth.

2,6-Dichloroindophenol↗