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Naturally occurring glycoproteins have been extracted from fundic and antral mucosal tissue of the hog stomach by means of nondegrading techniques. Major and retarded glycoprotein fractions separated by gel filtration were further dissociated from appreciable amounts of noncovalently bound proteins by CsCl density gradient centrifugation. Antisera to glycoprotein fractions of fundic and antral regions of the stomach were prepared in rabbits. The major fractions from both gastric regions have similar molecular mass (approximately 2 x 10(6)), sedimentation coefficient (approximately 31.5 s), and specific viscosity (approximately 1.6). Purified fractions from each region were further separated into two subfractions by affinity chromatography on wheat germ lectin. Glycoprotein subfractions from antrum and fundus differ appreciably in their carbohydrate and amino acids content, share antigenic determinants, but do not cross-react with anti-hog serum protein antisera. Further diversity in native mucin glycoproteins was observed by the use of one-(D) and two-dimensional (2D) immunoelectrophoresis; subfractions that cross-react with specific anti-hog gastric glycoproteins were found to contain three or more components. D-Immunoelectrophoretic analyses demonstrated (1) in vivo degradation of glycoprotein components of the major fundic fraction isolated from mucosal tissue of alcohol/acetyl salicylate-intoxicated hog stomachs and (2) in vitro catabolism of major fundic glycoproteins by corresponding mitochondrial lysosomal (ML) acid hydrolases. Furthermore, 2D-immunoelectrophoretic analyses showed that (1) hog synovial fluid and plasma proteins have similar prosthetic moieties as either reacted with anti-hog serum proteins antisera. Nonetheless, locations, shapes, and staining intensities of the immunoprecipitate lines differed, which is indicative of different structures of the carbohydrate moieties of components of synovial fluid and plasma proteins, and (2) only a minor fraction of hog cerebrospinal fluid cross-reacted with anti-hog serum protein antisera. This is contrary to the generally accepted deduction based on high-resolution 2D-electrophoresis, indicative of different compositional patterns of plasma and cerebrospinal fluids.
We have isolated several Saccharomyces cerevisiae mutants resistant to calcofluor that contain mutations in the PBS2 or HOG1 genes, which encode the mitogen-activated protein kinase (MAPK) and MAP kinases, respectively, of the high-osmolarity glycerol response (HOG) pathway. We report that blockage of either of the two activation branches of the pathway, namely, SHO1 and SLN1, leads to partial resistance to calcofluor, while simultaneous disruption significantly increases resistance. However, chitin biosynthesis is independent of the HOG pathway. Calcofluor treatment also induces an increase in salt tolerance and glycerol accumulation, although no activation of the HOG pathway is detected. Our results indicate that the antifungal effect of calcofluor depends on its binding to cell wall chitin but also on the presence of a functional HOG pathway. Characterization of one of the mutants isolated, pbs2-14, revealed that resistance to calcofluor and HOG-dependent osmoadaptation are two different physiological processes. Sensitivity to calcofluor depends on the constitutive functionality of the HOG pathway; when this is altered, the cells become calcofluor resistant but also show very low levels of basal salt tolerance. Characterization of some multicopy suppressors of the calcofluor resistance phenotype indicated that constitutive HOG functionality participates in the maintenance of cell wall architecture, a conclusion supported by the antagonism observed between the protein kinase and HOG signal transduction pathways.
Leucine aminopeptidase (LAP) was purified from hog lenses by application of the Himmelhoch procedure for isolation of hog kidney LAP [S. R. Himmelhoch (1970) in Methods in Enzymology (Perlmann, G. E., and Lorand, L., eds.), Vol. 19, pp. 508-513, Academic Press, New York.] This involved treating crude hog lens homogenates with hexadecyltrimethylammonium bromide, DEAE-cellulose adsorption and elution, ammonium sulfate fractionation (53-84% of saturation), and gel filtration on a Bio-Gel A-1.5m column. Purifications ranging from 2080- to 4700-fold with activity yields from 28 to 100% were achieved. The hog lens LAP appeared homogeneous by native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE). Bio-Gel chromatography of the native enzyme and SDS-PAGE of dimethylsuberimidate-crosslinked LAP indicated a molecular weight of 326,000. SDS-PAGE of untreated LAP showed a subunit weight of 54,000, consistent with a hexameric enzyme structure. By immunodiffusion, LAP from hog lens and kidney were identical while hog lens and beef lens enzymes demonstrated only partial identity. Electrophoresis of the native enzymes showed a slightly lower mobility for the hog lens LAP than for beef LAP at pH 8.7.
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Some conditions are presented under which swine develop antibodies for a soluble hog cholera viral antigen (HCA). Precipitating antibodies for HCA were present in all of the immune and hyperimmune anti-hog cholera sera tested. Antibodies for HCA could not be detected in the sera from a large number of swine after vaccination with inactivated hog cholera virus. Many of these same swine did produce HCA-antibodies following challenge with virulent virus. The incidence of these antibodies was significantly higher 3 weeks to one month after challenge than at 10 days. About one-fourth of a smaller group of swine developed HCA-antibodies after vaccination with modified active hog cholera virus vaccine. Exposure to active hog cholera virus appears prerequisite for swine to develop HCA-antibodies.
Evidence that the swine lungworm can serve as reservoir and intermediate host for the hog cholera virus has been presented. The virus, however, is ordinarily carried in a masked form and must be provoked to pathogenicity by some stress before it can cause apparent disease. In the present experiments, ascaris larvae supplied the provocation needed to induce hog cholera in swine carrying lungworms infected with masked hog cholera virus. Provocation of the masked virus by ascaris larvae was seasonal in that it was effective only during a period embracing the first 5 months of the year.
Suspensions of adult lungworms, procured from swine that were outwardly healthy but derived from eggs passed by swine with hog cholera, induced this disease in a small proportion of swine into which they were injected intramuscularly. This result was achieved in both lungworm-free and lungworm-infested swine, though perhaps slightly more regularly in the lungworm-infested animals. Swine that had had an intramuscular injection of lungworm suspension and that had remained normal, developed hog cholera much more regularly following the ingestion of lungworm larvae of cholera origin than did swine not previously injected with lungworms. The findings described were markedly dependent upon season and were regularly reproducible only during the first 4 or 5 months of the year. The results presented are considered as further evidence that the swine lungworm serves as reservoir and intermediate host for hog cholera virus and that the virus is ordinarily carried by the lungworm in a masked form which must be provoked to pathogenicity by some stress before it can cause obvious disease in swine.
Using a polyclonal antibody raised in rabbits against the highly purified di-isopropyl-fluorophosphate fluorohydrolase (DFPase, E.C. 3.8.2.1) of hog kidney, DFPase-immunoreactivity could be demonstrated by the unlabelled antibody peroxidase-antiperoxidase immunohistochemical method in the hog kidney in the brush border of epithelial cells in the proximal segment of the nephron. In the heart DFPase-immunoreactivity was found at the plasma membranes of the cardiac muscle cells.
To investigate whether live attenuated pseudorabies virus (PRV) can be used as a vaccine vector, PRV recombinants that expressed envelope glycoprotein E1 of hog cholera virus (HCV) were generated. Pigs inoculated with these recombinants developed high levels of neutralizing antibodies against PRV and HCV and were protected against both pseudorabies and hog cholera (classical swine fever).
Mosquitoes trapped during an epizootic of hog cholera (HC) in Maryland in 1969 were prepared into 40 pools which were inoculated in pigs. Hog cholera virus was confirmed in pigs inoculated with 8 of 40 pools of mosquitoes. Generally, the pigs contracting HC developed chronic infections with persistent viremia that lasted 30 or more days. Two pigs seemed healthy when euthatized 62 and 80 days after inoculation, yet viremia of high titer was detected in each. Experimental studies were performed with 2 laboratory strains of mosquitoes, Aedes aegypti and Culex tarsalis, to determine if biological and mechanical transmission occur. Biological transmission was not confirmed, but HC virus was retained in A aegypti for 3 days. Mechanical transmission was confirmed with A aegypti in 2 of 9 experiments.
The processing and protective capacity of E1, an envelope glycoprotein of hog cholera virus (HCV), were investigated after expression of different versions of the protein in insect cells by using a baculovirus vector. Recombinant virus BacE1[+] expressed E1, including its C-terminal transmembrane region (TMR), and generated a protein which was similar in size (51 to 54 kDa) to the size of E1 expressed in swine kidney cells infected with HCV. The protein was not secreted from the insect cells, and like wild-type E1, it remained sensitive to endo-beta-N-acetyl-D-glucosaminidase H (endo H). This indicates that E1 with a TMR accumulates in the endoplasmic reticulum or cis-Golgi region of the cell. In contrast, recombinant virus BacE1[-], which expressed E1 without a C-terminal TMR, generated a protein that was secreted from the cells. The fraction of this protein that was found to be cell associated had a slightly lower molecular mass (49 to 52 kDa) than wild-type E1 and remained endo H sensitive. The high-mannose units of the secreted protein were trimmed during transport through the exocytotic pathway to endo H-resistant glycans, resulting in a protein with a lower molecular mass (46 to 48 kDa). Secreted E1 accumulated in the medium to about 30 micrograms/10(6) cells. This amount was about 3-fold higher than that of cell-associated E1 in BacE1[-] and 10-fold higher than that of cell-associated E1 in BacE1[+]-infected Sf21 cells. Intramuscular vaccination of pigs with immunoaffinity-purified E1 in a double water-oil emulsion elicited high titers of neutralizing antibodies between 2 and 4 weeks after vaccination at the lowest dose tested (20 micrograms). The vaccinated pigs were completely protected against intranasal challenge with 100 50% lethal doses of HCV strain Brescia, indicating that E1 expressed in insect cells is an excellent candidate for development of a new, safe, and effective HCV subunit vaccine.
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