DIFFERENTIAL AMPLIFICATION OF ACHOLEPLASMA LAIDLAWII PG8 rrnA AND rrnB NUCLEOTIDE SEQUENCES DURING DISSOCIATION OF THE CELL CULTURE POPULATION

The amplification of the 16S–23S spacer areas of the Acholeplasma laidlawii PG8 rRNA rrnA and rrnB operons has its own features. The attenuation of the polymerase chain reaction (PCR) signal of the nucleotide sequences of rrnA containing tRNA genes might be observed if DNA without enzyme deproteinization is used as a matrix. The phenomenon takes place due to dissociation of cell population caused by the active entering of the vegetative cell forms into ultramicroforms in the mycoplasma culture at unfavorable growth conditions. The DNA of A. laidlawii PG8 ultramicroforms showed selective amplification of the rrnB nucleotide sequences – tRNA-free rRNA operon. As to vegetative cells, the “equal” PCR signals for the nucleotide of rrnA and rrnB sequences were registered. In this connection, the use of specific nucleotide sequences of the rrnA spacer area as primers for PCR, as well as the mycoplasma cell DNA without special enzyme deproteinization as a matrix, may lead to wrong conclusions about the presence of A. laidlawii in the tested samples. The ability of A. laidlawii PG8 vegetative cell forms of actively entering into ultramicroforms at unfavorable growth conditions seems to demand a new approach to control mycoplasma infections, providing an efficient diagnosis to detect the vegetative cell forms and ultramicroforms of the mycoplasma in the tested samples.