Project description:Kinetoplastids are a group of parasite species, several of which cause important diseases in human and livestock. Nearly all of these pathogenic species are transmitted by insect vectors, in which the parasites undergo a specific developmental program. One shared event undergone by multiple species is adherence to insect tissue. This adhesion occurs by means of a hemidesmosome-like structure that is thus far uncharacterized. We have used the monoxenous parasite Crithidia fasciculata, which exclusively infects mosquitoes, to study this process of parasite adhesion in the insect. We have transcriptionally profiled adherent and swimming forms of the parasite that have been generated in vitro, and compared these profiles to the adhesive form in the mosquito. Using a dual-RNAseq approach, we have also identified several genes that are differentially regulated in infected versus uninfected mosquitoes, including several immune genes. This indicates that the mosquito is responding to the presence of the parasites.
Project description:Insect hemocytes mediate important cellular immune responses including phagocytosis and encapsulation, and also secrete immune factors such as opsonins, melanization factors, and antimicrobial peptides. In Anopheles, they contribute to the defense against malaria parasite invasion during the early sporogonic cycle. We used microarrays to identify if and to what degree circulating hemocytes have altered global expression profiles after infection with the rodent malaria parasite, Plasmodium berghei
Project description:To address whether T. brucei has a circadian clock we probed its transcriptome by RNA-seq, searching for transcripts oscillating with a 24 hr period. For this we entrained/ synchronized parasites in vitro for three days using temperature and light as environmental stimuli and then collected parasite RNA every four hours for two consecutive days. Parasite RNA was subjected to RNA-seq analysis. We performed this protocol on two stages of the T. brucei life cycle (bloodstream and insect procyclic forms).
Project description:Insect hemocytes mediate important cellular immune responses including phagocytosis and encapsulation, and also secrete immune factors such as opsonins, melanization factors, and antimicrobial peptides. In Anopheles, they contribute to the defense against malaria parasite invasion during the early sporogonic cycle. We used microarrays to identify if and to what degree circulating hemocytes have altered global expression profiles after infection with the rodent malaria parasite, Plasmodium berghei Hemocytes were isolated 24-28h after infection using the infectious EGFP-CON P. berghei strain (experiment) or an invasion-deficient, Circumsporozoite- and TRAP-related protein (CTRP) knockout strain with the same genetic background as GFP-CON (CTRPko/GFP, control).
Project description:We determined the 16S rRNA gene sequences of three crustacean "Rickettsiella armadillidii" strains. Rickettsiella bacteria overall appear to form a monophyletic group that diverged from Coxiella bacteria approximately 350 million years ago. Therefore, the genus Rickettsiella as a whole (not just Rickettsiella grylli) should be classified among the Gammaproteobacteria instead of the Alphaproteobacteria.
Project description:Insect hemocytes mediate important cellular immune responses including phagocytosis and encapsulation, and also secrete immune factors such as opsonins, melanization factors, and antimicrobial peptides. In Anopheles, they contribute to the defense against malaria parasite invasion during the early sporogonic cycle. We used microarrays to identify transcripts that are specific or enriched in circulating hemocytes compared to either neuronal or to the rest of the body.
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.