Abstract: There is disclosed a process for screening an agent to determine whether it increases the frequency of genome rearrangement in living matter.In the first step of this process, there is provided viable mammalian cells which comprise repeated genetic elements in their haploid genome. These repeated genetic elements are selected from the group consisting of functional and non-functional genetic elements; and these elements are sufficiently homologous so that, under ambient conditions, they recombine with each other and give rise to an identifiable genome rearrangement.In the second step of this process, the viable mammalian cells are exposed to the agent to be tested. Thereafter, they are incubated in growth medium which, after the exposed cells grow in it, facilitates the identification of those cells which have undergone said genome rearrangement.In the last step of the process, the extent to which the exposed mammalian cells have undergone genome rearrangement is determined.

Abstract: Methods of biological control of agricultural insect pests are disclosed. These methods utilize biological control agents which are genetically altered strains of root-colonizing strains of members of the species P. cepacia. These strains are genetically altered by introduction of genes encoding insect toxic crystal proteins, and are thereby rendered insect toxic. Genetically altered insect toxic bacterial strains are also provided.