Biomedical subjects
D O Huggett
Publications and source records attributed to D O Huggett.
Infectious antibody-reovirus complexes.
Populations of reovirus type 1 could not be completely neutralized by exposure to specific antiviral serum. Aggregation of reovirions before or after exposure to neutralizing antibody was discarded as a possible explanation for the phenomenon observed. Anti-rabbit serum and equilibrium zonal density gradient centrifugation were used to show that the residual infectious fraction consisted of infectious antibody-virion complexes. Electron microscopy and equilibrium density gradient centrifugation of stock virus preparations were used to attempt to determine whether the infectious virus-antibody complexes resulted from the combination of antibody with virus particles which differed from neutralizable virions either morphologically or with regard to buoyant density. Although electron micrographs revealed the presence of three morphologically distinct classes of virus particles, density gradient centrifugation resulted in only one infectious peak. Density gradient centrifugation of virus exposed to antibody resulted in only one infectious peak which consisted of virus-antibody complexes.
Synergism between hyperoxia and antibiotics for Pseudomonas aeruginosa.
Three strains of Pseudomonas aeruginosa were directly exposed on the surface of membrane filters to hyperoxic atmospheres. One of the three strains was found to be sensitive to oxygen. Colonies failed to appear during 18 hr of incubation in pure oxygen at 1 atm, but about 40% of the bacteria recovered to produce colonies upon reincubation in air. Similar killing was produced by 10 hr of oxygen exposure. No inhibition or killing was observed with two other strains. Streptomycin (1mug/ml) and kanamycin (5mug/ml) were more effective in killing the oxygen-sensitive strain in the presence of 60 to 70% oxygen than in air, but polymyxin B (5mug/ml) did not show a synergistic effect under such conditions.
Effects in hyperoxia upon microorganisms. I. Membrane culture technique for exposing cells directly to test atmospheres.
A membrane culture technique was developed for directly exposing microorganisms to test atmospheres. Inhibition and killing were calculated from comparisons with air-grown cultures. Direct colony counts were used with low inocula. With mass inocula, plate colony counts and optical-density measurements were made on resuspended filter populations. Bacteria, including Escherichia coli, were more sensitive to oxygen than previously reported. With inocula of a few hundred cells per membrane, five of seven species failed to produce colonies while exposed to oxygen at one atmosphere. Upon reincubation in air, the survival of five species ranged from near 0 to 12% of the cells. Aerobacter aerogenes was neither inhibited nor killed. With this technique, bacteria are in direct contact with the test atmosphere and cells which survive are detected but do not obscure the response of other cells in the population.