ИСТИНА

Black garden ant Lasius niger is a well-studied and wide spread species, it dominates ant communities in many European cities and often is better represented in urban areas than in undisturbed natural habitats. Moreover, its genome was recently published, providing basis for assumptions about the biological success of L. niger in urbanized habitats. According to previous studies, cytochrome P450 genes of the family 9e2 (CYP9E2) are amplified in the genome. This cytochrome family is involved in the detoxification of various xenobiotics, including myco- and phytotoxins. In addition, L. niger has a smaller number of olfactory receptor (OR) genes compared to other insects. The aim of the research was to discover how the expression levels of CYP9E2 and OR correlate with the ability to live in urbanized habitats. For the experiment standard methods of RNA extraction, cDNA synthesis and real-time PCR were used. The ants were collected within the Moscow city (inside the Moscow Automobile Ring Road) and in the suburbs during this and previous summer. In Moscow the ants were collected under the curb neighboring the industrial area, whereas the suburban ants were collected in the fields. Expression levels of CYP9E2, Odorant Receptor and two housekeeping genes were studied, the RNA of the frozen ants was extracted via standard phenol-chloroform extraction. Further, the samples were diluted and treated with DNAse to get rid of the genomic DNA. Then the cDNA was synthetized using the sample’s RNA. Finally, the expression rates were shown by the real-time PCR. The experiment suggested that expression levels of CYP9E2 in black garden ant differ from the ones of Odorant Receptor genes, and thus may correlate with the number of gene copies found in the genome. To test this, the expression levels were studied in ants collected in various polluted sites in Moscow and in clean areas out of the city. Now we can say that CYP9E2 genes are the most expressed in all samples. Very rarely housekeeping genes H1 and L8 are amplified at the same cycle as the CYP9E2, more often their amplification is detected 4 or 6 cycles later. In conclusion, the results provide that CYP9E2 are overexpressed in L. niger, indicating their importance in metabolism of xenobiotics, whereas OR are expressed inconstantly, but when occurred, the expression is very low, which may reflect an insignificant role of smell for this species or the adaptation to the intense odor habitats. Moreover, the suburban populations show higher expression levels than the city ones. The results contribute to the understanding why L. niger is so widely spread in urbanized habitats.