Project description:Genome assemblies can form the basis of comparative analyses fostering insight into the evolutionary genetics. Genome evolution influences a parasite’s pathogenicity, host–pathogen interactions, environmental constraints and invasion biology. Comparative genomics and epigenomics analyses will provide deep understanding of parasitism biology for future diagnosis and prevention of trchinellosis. We provide a near-complete new T.p reference genome using SMRT technology, first time confirmed and characterized T.p DNA methylome, enabling full annotation. Based on this new version, we show repetitive sequences play important role in genome expansion, in synergy with DNA methylation during evolution. We further portrait the genomic and epigenomic regulation on E-S products in relation with their parasitism differences, especially for two super-families, including DNase II and EGF-like domain proteins.
Project description:Adaptation of eukaryotic cells to anaerobic condition is reflected by deep changes in mitochondrial metabolism and their functional reduction. The most modified types of mitochondria are hydrogenosomes that generate molecular hydrogen with concomitant ATP synthesis and mitosome that completely lost energy metabolism. The reduction of mitochondria is associated with loss of peroxisomes that evolved from ER to compartmentalize pathways generating reactive oxygen species (ROS) and thus prevent cellular oxidative damage. Biogenesis and function of peroxisomes is tightly coupled with mitochondria. They share the fission machinery, pathways of oxidative metabolism, ROS scavenging, and metabolic products. The loss of peroxisomes in anaerobic eukaryotes with reduced mitochondria is thus not unexpected. Surprisingly, we identified peroxisomes in anaerobic, hydrogenosome bearing protist Mastigamoeba balamuthi. Initially, we identified conserved set of peroxisomal proteins peroxins that are required for protein import, peroxisomal growth and division. Key membrane associated peroxins (MbPex3, MbPex11, and MbPex14) were visualized in numerous vesicles that were distinct from hydrogenosomes, ER and Golgi body. Proteomic analysis of cellular fractions and prediction of peroxisomal targeting signals (PTS1/PTS2) allows identification of 51 putative peroxisomal matrix proteins. Expression of selected proteins in Saccharomyces cerevisiae revealed that they are specifically targeted to yeast peroxisomes. Matrix protein includes components of acyl CoA and carbohydrate metabolism, pyrimidine and CoA biosynthesis, whereas neither components of β-oxidation nor catalase were present. In conclusion, we identified new subclass of peroxisomes named “anaerobic” peroxisome that shifts the current paradigm and rises attention to reductive evolution of peroxisomes in anaerobic organisms.
Project description:The evolution of parasitism is a recurring event in the history of life and a core question in evolutionary biology. Trypanosomatids are important parasites including the human pathogens Trypanosoma brucei, T. cruzi and Leishmania spp., which have evolved complex life cycles to exploit a series of defined host environments after diverging from free-living, phagotrophic bodonids. However, the origins of genomic adaptations for transmission, disease and pathogenesis remain obscure because there has been no genomic comparison of parasitic and free-living species. Addressing this absence, we have produced a genome sequence for Bodo saltans, the closest known non-parasitic relative of trypanosomatids. Here we show how genomic reduction and innovation contributed to the character of trypanosomatid genomes. We find that despite a genetic ‘streamlining’ of diverse physiological functions, including macromolecular degradation and cellular homeostasis, the origin of trypanosomatid parasitism did not lead to a substantial reduction in genome function. Instead, we observe dramatic elaboration of gene families that facilitate host-parasite interactions and pathogenesis. We also show how parasite-specific proteins that characterize the enigmatic cell surfaces of Trypanosoma and Leishmania were derived from the same ancestral proteins, still represented in B. saltans. Our new evidence distinguishes adaptive innovations of trypanosomatids that post-date their parasitic origin from essentially kinetoplastid legacies of a free-living past. It shows that when the labile environment of a phagotrophic ancestor was replaced by the defined conditions of their various hosts, trypanosomatid physiology was reoriented towards host interaction, and ancestral structures were radically transformed to provide adaptations for obligate parasitism.
Project description:Parasitism is a major ecological niche for a variety of nematodes. Multiple nematode lineages have specialized as pathogens, including deadly parasites of insects that are used in biological control. We have sequenced and analyzed the draft genomes and transcriptomes of the entomopathogenic nematode Steinernema carpocapsae and four congeners (S. scapterisci, S. monticolum, S. feltiae, S. glaseri) distantly related to Caenorhabditis elegans. We used these genomes to establish phylogenetic relationships, explore gene conservation across species, identify genes uniquely expanded in insect parasites, and to identify conserved non-coding regulatory motifs that influence similar biological processes. Protein domain analysis of these genomes reveals a striking expansion of numerous putative parasitism genes including certain protease and protease inhibitor families as well as fatty acid- and retinol-binding proteins. We identify rapid evolution and expansion of the important developmental Hox gene cluster and identify novel conserved non-coding regulatory motifs associated with orthologous genes in Steinernema and Caenorhabditis. The deep conservation of the network of non-coding DNA motifs between these two genera for a subset of orthologous genes involved in neurogenesis and embryonic development suggests that a kernel of protein-DNA relationships is conserved through nematode evolution. We analyzed the gene expression of a total of 24 RNA-seq samples from 3 nematode species( S. carpocapsae, S. feltiae, and C. elegans) for comparative analysis. We collected the RNA at four developmental time points (mixed embryo, L1, infective juvenile/dauer, young adult) for each species in replicates.
Project description:To determine secreted proteins that involved in adaptation of nutrient sources and response to nutrient stresses, we analyzed transcriptomes of Pochonia chlamydosporia strain 170 under three different nutrient conditions, CD (nutrient rich medium) that was predicted to repress parasitism, MM (nutrient-poor liquid minimal medium) that was predicted de-repress genes associated with parasitism, and MM-eggs(minimal medium with root-knot nematode eggs) that was prepared to induce parasitism.