Bacterial isolates and cultivation conditions
A total of 190 samples of B. thuringiensis were studied. All samples were found in the zoo. To perform serological studies, the bacteria were grown at a temperature of 37°C for a period of 5 hours. Nutrient broth with a pH value of 7.5 was used for this purpose. The broth consisted of 15 g of meat extract, the same amount of polypeptone, as well as 1000 ml of distilled water and 3 g of sodium chloride. Bacterial growth was carried out on nutrient medium (nutrient agar consisting of 1 liter of broth, 30 g of agar). The temperature regime was 28°C and the cultivation time was 5-6 days. This was necessary for tests on pathogenic activity for insects, as well as for observations of sporulated cultures using a microscope.