Project description:In the past century, recently emerged infectious diseases have become major drivers of species decline and extinction. Amphibian declines have occurred due to the fungal disease chytridiomycosis, which has exacerbated the conservation crisis of this taxonomic group. Biologists are beginning to understand what traits are important for susceptibility to this disease, but more work is needed to determine why some species succumb to disease while others do not. We conducted a laboratory experiment to examine how two toad species respond to infection in controlled environment. We selected two related species thought to differ in susceptibility â?? Bufo marinus (an invasive and putatively resistant species) and B. boreas (an endangered and putatively susceptible species). We measured infection intensity, body weight, histological changes at the site of infection, and genome-wide gene expression changes using a custom assay developed from transcriptome sequencing. Our results confirmed that the two species differ in susceptibility. The more susceptible species, B. boreas, experienced higher infection intensities, loss in body weight, more dramatic histological changes, and larger perturbations in gene expression. We found key differences in skin expression responses in multiple pathways including up-regulation of skin integrity-related genes in the resistant B. marinus. Together our results show intrinsic differences in host response between related species, which are likely to be an important factor in explaining variation in response to a deadly emerging pathogen in wild populations. We processed 72 tissue samples in total: six biological replicates, three tissue types (ventral skin, liver, spleen), two treatment groups (pathogen exposed, control), and two host species (Bufo marinus, Bufo boreas). The custom Nimblegen microarray design included 135,200 60-bp probes (excluding control probes) targeting 31,367 transcript contigs from Bufo marinus, Bufo boreas, and model species Xenopus tropicalis, with 4 probes per probe-set. We used the 12-plex microarray platform (12 arrays per glass slide). Differential expression analyses were performed separately for each tissue type and host species.
Project description:Chansu, which is prepared from the skin secretions of toad (Bufo bufo gargarizans Cantor), is widely used in traditional Chinese medicine (TCM). Being the principal bioactive constituents of ChanSu, bufalin (BFL) and cinobufagin (CBF) have been shown to possess anticancer properties. TCM confer bioactivities through the synergistic effect between potential active ingredients, so as to interfere with the development of the disease, and ultimately achieve the therapeutic effect. We found that the anticancer effect was significantly potentiated by co-treatment of BFL and CBF as compared to mono-treatment, suggesting their synergistic interaction. To reveal their synergistic mechanisms, metabolomic and lipidomic profiling based on liquid chromatography-mass spectrometry (LC���������MS) were utilized to delineate the responses in HepG2 cells after treatment with BFL and CBF individually or in combination. Metabolic pathways including methionine metabolism, energy metabolism, lipid metabolism and amino acid metabolism were modulated and subsequently lead to apoptosis and cell cycle arrest of HepG2 cells. In particular, the discrepant regulation of methionine metabolism between mono-treatment and co-treatment of BFL and CBF may account for their synergistic effect. Our study provided novel insights into the mechanistic links between cellular metabolism and synergistic effect, which may ultimately lead to better treatments for hepatoma.