CHANGED GENOMES OF TICK-BORNE ENCEPHALITI S-VIRUS STRAINS AFTER PASSAGES IN MICE

Changes in genomes of TBE strains isolated from various sources at ear ly stages of laboratory adaptation to white mice brain were demonstrat ed by molecular hybridization of nucleic acids with synthetic oligonuc leotide probes, complementary RNA sites of reference TBE strains Sofyi n and Neudorf. Of the 4 TBE strains passed 6 times through white mice brain in only 1 the level of RNA hybridization with 2 oligonucleotide probes was found changed, whereas in all the 3 tested strains the leve l of RNA hybridization with 1-2 oligonucleotide probes complementary t o strain Sofyin was increased after 7-16 passages in the same system. The most noticeable changes in the genome were detected during readapt ation to white mice of a TBE variant selected in passages on H. margin atum marginatum ticks.