ABUNDANCE OF TN3, TN21, AND TN501 TRANSPOSASE (TNPA) SEQUENCES IN BACTERIAL COMMUNITY DNA FROM MARINE ENVIRONMENTS

The occurrence of the tnpA genes of the transposons Tn3, Tn21, and Tn5 01 was assessed in total bacterial community DNA isolated from differe nt marine environments. The PCR technique was employed, together with most probable number statistics, to determine the abundance of the tar get tnpA genes. All three genes could be detected, and the Tn21 tnpA s equences predominated in all samples. The smallest amount of total com munity DNA in which the Tn21 tnpA sequence could be detected was 0.037 ng, and on the basis of our results, we estimated that this sequence was present in 1 of 1,000 to 10,000 bacteria. Hybridization of the PCR products with the respective tnpA probes verified the Tn21 and Tn501 tnpA sequences but only some of the Tn3 tnpA amplification products. T he distribution and dissemination of transposons in natural bacterial communities are discussed.