TY  - THES
A3  - Merzendorfer, Hans
AB  - Most insects are beneficial creatures, but among them are many pests that can pose a risk to human nutrition and health. Because of this, insects are need to be controlled, which can be achieved by various classes of insecticides. Due to the fact that insecticide resistance is increasing worldwide, a profound knowledge on the underlying mechanisms of insecticide resistance becomes more and more important. One way to eliminate insecticide from the insect body involves integral transmembrane proteins such as ATP-binding cassette (ABC) transporters, which mediate the ATP-dependent translocation of a variety of substrates across cell membranes, including xenobiotics. While ABC transporters have been extensively analysed in bacteria and vertebrates, little is known about their physiological functions in insects. A previous study of ABC transporters in the red flour beetle, Tribolium castaneum, revealed that the genome of this beetle harbours more than 70 ABC transporter encoding genes. Those can be grouped into eight known insect subfamilies namely ABCA to ABCH. The ABCB and ABCC subfamilies contain P-glycoproteins (P-gp or MDR) and multidrug resistance proteins (MRP) that are discussed to contribute to insecticide elimination. Other transport proteins include the organic anion transporting polypeptides (OATPs), which also transport a large variety of substrates across cell membranes. Some of them are expressed together with ABC transporters or other detoxification enzymes in the same tissues, and hence may play an important role in the transport of insecticides and/or their metabolites. T. castaneum is a well-established genetic pest model, allowing the analysis of gene functions in the development of insecticide resistances. To identify transporters involved in insecticide elimination, three methods were used in this study: (1) gene expression analyses, (2) a competitive fluorescence-based elimination assay and (3) ABC and OATP inhibitors. Different TcABC and TcOATP genes were found to be upregulated in excretory tissues and insecticide-treated larvae. RNA interference (RNAi) was used to analyse the influence of ABC transporters and OATPs and the knockdown of specific ABC and OATP genes resulted in a significant increase in mortality of insects that were treated with different insecticides. Moreover, RNAi knockdowns of some specific ABC and OATP genes led to mortality even in the absence of any insecticide. Their phenotypes resemble other genes known to be involved in the hormonal control of ecdysteroids indicating essential physiological functions during molting. In summary, the data presented in this study show that ABC transporters and OATPs are involved in the elimination of insecticides and in the transport of ecdysteroids.
AU  - Rösner, Janin
DA  - 2021
DO  - 10.25819/ubsi/9996
KW  - Tribolium castaneum
KW  - Insecticide
KW  - Resistance
KW  - physiology
LA  - eng
PY  - 2021
TI  - Identification and analysis of transporters involved in the elimination of insecticidal compounds from the red flour beetle, Tribolium castaneum
TT  - Identifizierung und Analyse von Transportern, die an der Eliminierung von insektiziden Verbindungen durch den rotbraunen Reismehlkäfer, Tribolium castaneum, beteiligt sind
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:467-19835
Y2  - 2024-11-23T12:17:10
ER  -