Project description:Expression of bumblebees (Bombus terrestris) from four colonies exposed to 3 different genotypes of the trypanosome parasite Crithidia bombi
Project description:Expression of bumblebees (Bombus terrestris) from four colonies exposed to 3 different genotypes of the trypanosome parasite Crithidia bombi RNA from guts of exposed individuals. Sacrificed 18hr after exposure.
Project description:Pesticides pose a potential threat to bee health, especially in combination with other stressors, like parasites. However, pesticide risk assessment tests them in isolation from other stresses. We tested acute oral doses of three pesticides - glyphosate, Amistar and sulfoxaflor - on the bumblebee, Bombus terrestris, alongside the gut parasite Crithidia bombi. We found no impact of any pesticide on parasite intensity and no impact of sulfoxaflor or glyphosate on survival or weight change. Amistar caused weight loss and 19-41% mortality. Haemoproteome analysis showed various protein dysregulations. The major pathways dysregulated are those involved in insect defences and immune responses, with Amistar having the strongest impact on these. Our results show that while no response can be seen at a whole organism level, MALDI BeeTyping® can detect effects. Mass spectrometry analysis of bee haemolymph represent a pertinent tool to evaluate the stressor impacts on bee health, even at the individual scale.
Project description:Trypanosomatid parasites undergo developmental regulation to adapt to the different environments encountered during their life cycle. In Trypanosoma brucei, a genome wide selectional screen previously identified a regulator of the protein family ESAG9, which is highly expressed in stumpy forms, a morphologically distinct bloodstream stage adapted for tsetse transmission. This regulator, TbREG9.1, has an orthologue in Trypanosoma congolense, despite the absence of a stumpy morphotype in that parasite species, which is an important cause of livestock trypanosomosis. RNAi mediated gene silencing of TcREG9.1 in Trypanosoma congolense caused a loss of attachment of the parasites to a surface substrate in vitro, a key feature of the biology of these parasites that is distinct from T. brucei. This detachment was phenocopied by treatment of the parasites with a phosphodiesterase inhibitor, which also promotes detachment in the insect trypanosomatid Crithidia fasciculata. RNAseq analysis revealed that TcREG9.1 silencing caused the upregulation of mRNAs for several classes of surface molecules, including transferrin receptor-like molecules, immunodominant proteins, and molecules related to those associated with stumpy development in T. brucei. Depletion of TcREG9.1 in vivo also generated an enhanced level of parasites in the blood circulation consistent with reduced parasite attachment to the microvasculature. The morphological progression to insect forms of the parasite was also perturbed. We propose a model whereby TcREG9.1 acts as a regulator of attachment and development, with detached parasites being adapted for transmission.
