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J P Dobbs

Publications and source records attributed to J P Dobbs.

10 recordsLinked to original sources
PubMed1968

Purification and properties of in vitro-produced anthrax toxin components.

The three components of the toxin of Bacillus anthracis, edema factor (EF), protective antigen (PA), and lethal factor (LF), were purified 197-, 156-, and 1,025- fold, with 38, 78, and 11% recovery, respectively. Each purified component was serologically active, distinct, and free from the other components. The purified EF produced edema when mixed with PA, and the purified PA was an active immunogen. The components did not appear to be simple proteins by spectrophotometric analysis. As they were purified, the pH range in which they were most stable narrowed, centering between pH 7.4 and 7.8. Heat readily destroyed the biological activity of the components but not their serological activity. The rat lethality test showed that, with a constant amount of LF and an increasing amount of PA, the time to death reached a minimum and then was extended. When an increasing amount of LF was added to a constant amount of PA, the time to death became shorter as more LF was added. The biological, immunological, and serological properties of the components were shown to vary independently with storage and extent of purification so that serological activity was not always directly correlated with biological activity. Evidence is presented that the components can exist in different molecular configurations or as aggregates, and that this property is influenced by the state of component purity and by the environment.

Animals↗
PubMed1967

In vivo growth and distribution of anthrax bacilli in resistant, susceptible, and immunized hosts.

Differences in in vivo growth rates of Bacillus anthracis in the bodies of infected rats and guinea pigs showed the effect of innate species resistance. The effect of two levels of immunity imposed on these hosts demonstrated that, as the degree of immunity increased, the growth rate of organisms decreased and was accompanied by a decrease in terminal population. It was shown that growth rates in the blood best reflected the population growth in the entire host. Data obtained from the naturally resistant rat that had been immunized with both the Belton-Strange protective antigen and live vaccine demonstrated the role of "toxins" in terminal anthrax. The in vivo morphological changes in anthrax bacilli pointed out errors regarding estimates of true terminal population of organisms when samples for counting were taken postmortem rather than at the time of death.

Animals↗
PubMed1967

Antibiotic treatment of anthrax infection in mice.

Quantitative measurements of mean time to death, percentage of survivors, and viable cell populations in the whole body were employed to determine the effects of penicillin, dihydrostreptomycin, chlortetracycline, oxytetracycline, chloramphenicol, and antiserum on the course of anthrax infection in mice. By all parameters tested, penicillin and dihydrostreptomycin were most effective in the treatment of the disease. Therapy initiated in the later stages of the disease was more effective than that initiated in the earlier stages. Quantitative studies indicated that it was more difficult to eliminate organisms from the kidney than from any other organ or tissue. These measurements for the evaluation of antibiotic therapy are suggested for the study of other bacterial diseases.

Animals↗