Prospective fecal microbiomic biomarkers for chronic wasting disease.

Chronic wasting disease (CWD) is a naturally occurring prion disease in cervids that has been rapidly proliferating in the United States. Here, we investigated a potential link between CWD infection and gut microbiome by analyzing 50 fecal samples obtained from CWD-positive animals of different sexes from various regions in the USA compared to 50 CWD-negative controls using high throughput sequencing of the 16S ribosomal RNA and targeted metabolomics. Our analysis reveals promising trends in the gut microbiota that could potentially be CWD-dependent, including several bacterial taxa at each rank level, as well as taxa pairs, that can differentiate between CWD-negative and CWD-positive deer. Through machine-learning, these taxa and taxa pairs at each rank level could facilitate identification of around 70% of both the CWD-negative and the CWD-positive samples. Our results provide a potential tool for diagnostics and surveillance of CWD in the wild, as well as conceptual advances in our understanding of the disease.IMPORTANCEThis is a comprehensive study that tests the connection between the composition of the gut microbiome in deer in response to chronic wasting disease (CWD). We analyzed 50 fecal samples obtained from CWD-positive animals compared to 50 CWD-negative controls to identify CWD-dependent changes in the gut microbiome, matched with the analysis of fecal metabolites. Our results show promising trends suggesting that fecal microbial composition can directly correspond to CWD disease status. These results point to the microbial composition of the feces as a potential tool for diagnostics and surveillance of CWD in the wild, including non-invasive CWD detection in asymptomatic deer and deer habitats, and enable conceptual advances in our understanding of the disease.

Natural products dereplication by diffusion ordered NMR spectroscopy (DOSY).

Diffusion-ordered NMR spectroscopy (DOSY) can be used to analyze mixtures of compounds since resonances deriving from different compounds are distinguished by their diffusion coefficients (D). Previously, DOSY has mostly been used for organometallic and polymer analysis, we have now applied DOSY to investigate diffusion coefficients of structurally diverse organic compounds such as natural products (NP). The experimental Ds derived from 55 diverse NPs has allowed us to establish a power law relationship between D and molecular weight (MW) and therefore predict MW from experimental D. We have shown that D is also affected by factors such as hydrogen bonding, molar density and molecular shape of the compound and we have generated new models that incorporate experimentally derived variables for these factors so that more accurate predictions of MW can be calculated from experimental D. The recognition that multiple physicochemical properties affect D has allowed us to generate a polynomial equation based on multiple linear regression analysis of eight calculated physicochemical properties from 63 compounds to accurately correlate predicted D with experimental D for any known organic compound. This equation has been used to calculate predicted D for 217 043 compounds present in a publicly available natural product database (DEREP-NP) and to dereplicate known NPs in a mixture based on matching of experimental D and structural features derived from NMR analysis with predicted D and calculated structural features in the database. These models have been validated by the dereplication of a mixture of two known sesquiterpenes obtained from Tasmannia xerophila and the identification of new alkaloids from the bryozoan Amathia lamourouxi. These new methodologies allow the MW of compounds in mixtures to be predicted without the need for MS analysis, the dereplication of known compounds and identification of new compounds based solely on parameters derived by DOSY NMR.

Antiplasmodial Alkaloids from the Australian Bryozoan Amathia lamourouxi.

An extract from the bryozoan Amathia lamourouxi with antiplasmodial activity was identified through high-throughput screening of an Australian marine invertebrate extract library against Plasmodium falciparum. Chemical investigation of A. lamourouxi resulted in the isolation of six new brominated alkaloids, convolutamines K and L (1 and 2), volutamides F-H (3-5), and 2,5-dibromo-1-methyl-1H-indole-3-carbaldehyde (6). Three of the compounds (2-4) displayed moderate to potent antiplasmodial activity against both the chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) parasite strains of Plasmodium falciparum with an IC50 range of 0.57-1.7 µM and a high selectivity index against a human cell line (HEK293).

Orthoscuticellines A-E, ß-Carboline Alkaloids from the Bryozoan Orthoscuticella ventricosa Collected in Australia.

Antiplasmodial high-throughput screening of extracts derived from marine invertebrates collected from northern NSW, Australia, resulted in the methanol extract of the bryozoan Orthoscuticella ventricosa being identified as inhibitory toward the 3D7 strain of Plasmodium falciparum. Purification of this extract resulted in two new bis-ß-carbolines that possess a cyclobutane moiety, orthoscuticellines A and B (1 and 2), three new ß-carboline alkaloids, orthoscuticellines C-E (3-5), and six known compounds, 1-ethyl-4-methylsulfone-ß-carboline (6), 1-ethyl-ß-carboline (7), 1-acetyl-ß-carboline (8) 1-(1'-hydroxyethyl)-ß-carboline (9), 1-methoxycarbonyl-ß-carboline (10), and 1-vinyl-ß-carboline (11). The structures of all compounds were determined from analysis of MS and 1D and 2D NMR data. The compounds showed modest antiplasmodial activity against P. falciparum in the range of 12-21 µM.