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Biomedical subjects

C B Boyce

Publications and source records attributed to C B Boyce.

12 recordsLinked to original sources
PubMed1969

A purification and some properties of an insecticidal exotoxin from Bacillus thuringiensis Berliner.

An insecticidal exotoxin from Bacillus thuringiensis var. thuringiensis (Berliner) has been purified. The efficiency of each stage of the purification has been ascertained and the yield of toxic material estimated by means of a quantitative bioassay. It is shown that the exotoxin is an adenine derivative substituted at position 9 and having a molecular weight of approximately 825. It can be dephosphorylated enzymically or chemically under conditions that define the exotoxin as a phosphomonoester. This results in loss of toxicity, both to insects and to mice. Spectroscopic and kinetic data are presented which suggest that a beta-ribofuranosyl moiety may be attached to the adenine. Glucose and allomucic acid have been positively identified as hydrolysis fragments from the exotoxin. These results are discussed and compared with the results of others on similar (or possibly identical) compounds.

Adenine↗
PubMed1967

The susceptibility of Biomphalaria glabrata throughout its life-history to N-tritylmorpholine.

This study was undertaken as part of a detailed investigation of the molluscicidal properties of N-tritylmorpholine (Frescon, WL 8008). It is shown that the stage of development of Biomphalaria glabrata has a pronounced influence on its susceptibility to N-tritylmorpholine. As the snails grow from hatching to a diameter of 3 mm, the LC(50) falls from 0.04 ppm to 0.02 ppm, but further growth results in a progressive increase in LC(50) until, at a shell diameter of 20 mm, it is 0.17 ppm. N-Tritylmorpholine is much less toxic to snail eggs when used in short exposures. However, young embryos in capsules treated with 5 ppm for 24 hours developed abnormally and died without hatching. Older embryos developed normally but died after hatching. This delayed effect is attributed to contact, during hatching, with N-tritylmorpholine which is associated with the jelly. The difference in susceptibility between snails and eggs is attributed to a slow rate of penetration of the egg membrane.

Animals↗
PubMed1967

The molluscicidal activity of N-tritylmorpholine.

N-Tritylmorpholine (Frescon, WL 8008) is highly toxic to the intermediate-host snails of the Schistosomatidae. Molluscicidal concentrations range from 0.1 ppm to 0.5 ppm for 1-hour exposures and from 0.01 ppm to 0.05 ppm for 24-hour exposures. Under these conditions the compound is not toxic to snail eggs; recent work, however, shows that longer exposures are toxic. It has been successfully used to control snails in large-scale trials in several countries with very short exposures (4 ppm for 15 min), as well as in prolonged treatments (0.025 ppm for 16 days).These treatments have remarkably little effect on other forms of aquatic life; plants, insects and the microfauna and flora are unaffected, and in certain circumstances it has proved possible to control snails without harming fish populations. A detailed study of the toxicology of N-tritylmorpholine in mammals has shown that it does not present any toxic hazards.N-Tritylmorpholine can be formulated in a variety of ways, e.g., as emulsifiable concentrates, water-dispersible powders and granules, as well as some specialized types of formulations, such as baits and spreading oils. Laboratory and field studies have shown that environmental factors such as mud, light and vegetation have little effect on the performance of N-tritylmorpholine, but hydrolysis and loss of activity may occur in acid water.

Animals↗