Phlebotomus Tobbi Adler, Theodor & Lourie, 1930 (Diptera: Psychodidae)’nin Sıcaklığa Bağlı Gen Ekspresyon Seviyelerindeki Değişimler

Abstract

Phlebotomus tobbi Adler, Theodor and Lourie, 1930, is a vector sand fly species widely distributed in Turkey. This species is the proven vector of Leishmania infantum, Nicolle, 1908 protozoan parasites in the country and plays an important role in the transmission of many Phleboviruses. In this thesis, the effects of environmental factors on the gene expression levels of the P. tobbi transcripts are examined. In order to measure the direct effect of temperature on gene expression, laboratory colonies of P. tobbi are reared under different temperature conditions (23oC and 27oC) Differences in the expression levels of Cacophony (PtCac), Salivary Gland Protein 32 (PtSP32) and Salivary Gland Protein 38 (PtSP38) genes, which affect survival, development and disease occurrence, of adult female specimens obtained from these colonies were revealed. In order to observe the effect of environmental factors on gene expression, the expression levels of three genes in P. tobbi populations distributed in three different geographical regions (Adana, Datça and Yozgat) were compared. The relationships between gene expression levels and environmental factors were statistically tested by using the ambient temperature and relative humidity data of the sampling areas. In addition, protein patterns of natural P. tobbi populations were revealed by MALDI- TOF MS protein profile analysis method and the efficiency of the method in discrimination of geographic populations were investigated. Differences were observed between the Cac gene expression levels of both laboratory colonies and natural populations. Gene expression analyzes of laboratory colonies showed a positive correlation between Cac gene expression level and temperature. However, on the contrary, a negative correlation was found with environmental temperature in natural populations. A negative correlation was also observed between Cac gene expression levels and ambient relative humidity in these populations. On the other hand, while no statistically significant difference was observed in PtSP32 gene expression levels between 23oC and 27oC temperature conditions in laboratory colonies, differences were found among natural populations showing a negative correlation with environmental relative humidity. Although PtSP38 gene expression analyzes in laboratory colonies revealed differences between the two groups that showed a positive correlation with temperature, no statistically significant difference was found in PtSP38 gene expressions of natural populations. According to protein profile analysis of natural populations, although minimal differences were observed between populations, a clear discrimination could not be made between geographic populations of P. tobbi with current database using in the MALDI-TOF MS protein profile analyses. With this thesis, the gene expression changes of the L. infantum vector under different environmental conditions were revealed and the differentiation of P. tobbi geographic populations in Turkey by protein profiles was tested for the first time. The results will help to understand the dynamics of the vector in fluctuating environmental conditions and contribute the future studies conducted to determine the vector-parasite-host relationships and disease occurrence risk.