Modes of tetracycline resistance in Bacillus thuringiensis]

The sensitive strain and tetracycline-resistant mutants exhibit two types of growth curves after addition of tetracycline. The level of resistance of these strains is enhanced by a short period of preincubation with a non-inhibitive concentration of tetracycline.     

Sporeless mutants of Bacillus thuringiensis. II. mutants derived from var. thuringiensis and var. sotto.

Three sporeless mutants of Bacillus thuringiensis, 2 derived from var. thuringiensis and 1 from var. sotto were selected after mutagenic treatment. They were completely lacking in ability to form spores, yet maintained intact insecticidal activity.     

Morphologic alterations induced by aflatoxin B1 in Bacillus thuringiensis (Berliner)]

Significative ultrastructural alterations shown in aflatoxin B1, treated cells of Bacillus thuringiensis are: increase of number of mesosomes which are hypertrophied, decrease of ribosomes and formation of imperfect cell septa.     

Bacillus thuringiensis delta-endotoxin: evidence that toxin acts at the surface of susceptible cells

Enzymically activated delta-endotoxin of Bacillus thuringiensis covalently bound to Sephadex beads, has the same effect on insect cells in tissue culture as free toxin. The effect is prevented by antitoxin antibody and heat denaturation and is not due to a nonspecific protein effect, the beads, or toxin released from the beads. The toxin, therefore, probably acts at the cell surface.     

Cytological study of the action of Bacillus thuringiensis var. israelensis on mosquito larvae]

A comparison is made between the cytopathological effects of B. thuringiensis var. israelensis on Aedes aegypti larvae and the cytopathological effects of the other varieties of B. thuringiensis on Lepidoptera larvae. The same primary action is observed, with the loss of integrity of the gut epithelium, the cells of which appear swollen, distorted and finally burst.     

Toxicity of Bacillus thuringiensis var. israelensis for Simulium larvae, vectors of onchocerciasis]

On field trials in infested streams, the primary powder R 153-78 made of B. thuringiensis var. israelensis with a potency of 3,000 I.T.U. Aedes aegypti/milligramme is very toxic for Blackfly larvae, especially for Simulium damnosum s.l. larvae. The lethal concentration 100, in 24 h. is 0.2 X 10(-6) for a 10 min. treatment. This high toxicity, specific for Diptera larvae such as Mosquitoes and Blackflies, is related to the special characteristic of the bacterial crystal protein which has a clear serological and chemical individuality compared to the crystal proteins of the other B. thuringiensis serotypes essentially pathogenic for Lepidoptera larvae. These preliminary results are very promising and could lead, on further research, to the utilization of B. thuringiensis var. israelensis on large scale for onchoceriasis vector control in Africa.