Functional annotation of chemical libraries across diverse biological processes.

Chemical-genetic approaches offer the potential for unbiased functional annotation of chemical libraries. Mutations can alter the response of cells in the presence of a compound, revealing chemical-genetic interactions that can elucidate a compound's mode of action. We developed a highly parallel, unbiased yeast chemical-genetic screening system involving three key components. First, in a drug-sensitive genetic background, we constructed an optimized diagnostic mutant collection that is predictive for all major yeast biological processes. Second, we implemented a multiplexed (768-plex) barcode-sequencing protocol, enabling the assembly of thousands of chemical-genetic profiles. Finally, based on comparison of the chemical-genetic profiles with a compendium of genome-wide genetic interaction profiles, we predicted compound functionality. Applying this high-throughput approach, we screened seven different compound libraries and annotated their functional diversity. We further validated biological process predictions, prioritized a diverse set of compounds, and identified compounds that appear to have dual modes of action.

Errata: Functional annotation of chemical libraries across diverse biological processes.

This corrects the article DOI: 10.1038/nchembio.2436.

Errata: Functional annotation of chemical libraries across diverse biological processes.

This corrects the article DOI: 10.1038/nchembio.2436.

Chitogel improves long-term health economic outcomes following endoscopic sinus surgery in severe chronic rhinosinusitis patients.

Introduction: Chronic rhinosinusitis causes severe symptoms that can affect patient quality of life. Endoscopic sinus surgery can be effective in improving symptoms, although surgical outcomes can be compromised post-operatively, and revision surgery is required in a proportion of patients. This study compares outcomes and healthcare resource use in patients undergoing sinus surgery with or without Chitogel as a post-operative dressing. Methods: A retrospective cohort study was conducted using deidentified audit data from adult patients with severe chronic rhinosinusitis, who underwent endoscopic sinus surgery between January 2016 and December 2021. Patients in the intervention group received Chitogel as a post-operative dressing, and control patients received standard best-practice care. Cox Proportional Hazards survival analysis was used to compare revision surgery rates and time to revision between treatment groups. The rate of revision surgery was used to estimate potential health sector savings associated with use of Chitogel following surgery compared to the control arm, considering initial treatment costs and the cost of revision surgery. Results: Over 18-24 months, patients treated with Chitogel demonstrated significantly lower rates of revision surgery (p = 0.035), and a trend towards decreased use of post-operative steroids, compared to control. Potential health sector savings due to reduced rates of revision surgery following use of Chitogel are estimated as NZ $753,000 per 100 patients. Conclusion: Severe chronic rhinosinusitis patients treated with Chitogel had lower rates of revision surgery within the first 18-24 months post-operative. These findings suggest that use of Chitogel can improve long-term patient outcomes and should improve health system efficiency.

Structurally diverse hamigerans from the New Zealand marine sponge Hamigera tarangaensis: NMR-directed isolation, structure elucidation and antifungal activity.

The NMR-directed investigation of the New Zealand marine sponge Hamigera tarangaensis has afforded ten new compounds of the hamigeran family, and a new 13-epi-verrucosane congener. Notably, hamigeran F (6) possesses an unusual carbon­carbon bond between C-12 and C-13, creating an unprecedented skeleton within this class. In particular, the structural features of 6, hamigeran H (10) and hamigeran J (12) imply a diterpenoid origin, which has allowed the putative biogenesis of three hamigeran carbon skeletons to be proposed based on geranyl geranyl pyrophosphate. All new hamigerans exhibited micromolar activity towards the HL-60 promyelocytic leukaemic cell line, and hamigeran G also selectively displayed antifungal activity in the budding yeast Saccharomyces cerevisiae. Homozygous deletion profiling (HOP) analysis suggests Golgi apparatus function as a potential target of this unusual class of sponge-derived terpenoids.

Lehualides E-K, cytotoxic metabolites from the Tongan marine sponge Plakortis sp.

Spectroscopy-guided chemical analysis of a marine sponge from the genus Plakortis, collected in Tonga, yielded seven new metabolites of polyketide origin, lehualides E-K (5-11), four of which incorporate various sulfur functionalities. The structures of compounds 5-11 were elucidated by interpretation of spectroscopic data and spectral comparison with model compounds. The biological activities of compounds 6-9 were investigated against human promyeloid leukemic HL-60 cells and two yeast strains, wild-type and a drug-sensitive mutant.

Uptake of new medicines in New Zealand: evidence of a waiting list.

AIMS: The Pharmacology and Therapeutics Advisory Committee (PTAC) advises the Pharmaceutical Management Agency (PHARMAC) which medicines should be listed on the New Zealand Pharmaceutical Schedule. This research analyses the PTAC recommendations from 2006 to September 2014 and aims to identify the composition of a waiting list of medicines, including levels of PTAC priority for positive recommendations and measure mean waiting times for these medicines to receive public funding. METHOD: Funding recommendations in the minutes of the New Zealand Pharmacology and Therapeutics Advisory Committee (PTAC) from 2006 to September 2014 were analysed and compared with the New Zealand Pharmaceutical Schedule for the same period. A list is developed, comprised of agents that received a positive funding recommendation from PTAC, but are still unlisted in the schedule. Waiting periods were measured from the time of the first positive PTAC recommendation to September 2014. RESULTS: There are 29 medicines (for 31 indications) awaiting listing on the pharmaceutical schedule after receiving positive PTAC recommendations. Delays to listing of these medicines range between 0.3 years and 8.2 years. Somewhat surprisingly, mean waiting times did not differ substantially between different listing priorities assigned by PTAC. CONCLUSIONS: There are a substantial number of medicines awaiting funding in New Zealand after receiving positive recommendations from PTAC. We recommend that in the interest of transparent reporting, PHARMAC regularly publish a list of pharmaceuticals awaiting listing on the Pharmaceutical Schedule; their PTAC priority status; and the length of time they have been waiting.

Chemical genetic and chemogenomic analysis in yeast.

Chemogenomics is the systematic genome-wide study of the cellular response to small molecule agents. Modern high-throughput genetic techniques allow massively parallel examination of the genetic effects of such biologically active small molecules (BASM). Here we present methodology for the identification and characterization of potentially bioactive compounds using the budding yeast Saccharomyces cerevisiae as a model organism. First, we present a method for screening libraries of compounds for growth inhibition in solid or liquid phase, followed by techniques for potency determination using a half-log dose response. Then the Deletion Mutant Array (DMA), a genome-wide library of single gene deletion strains, is used to probe the chemical genetic interactions of individual BASMs on genetic networks-a process that can be achieved with a solid phase pinning assay or a pooled liquid assay utilizing barcode microarray techniques. Finally, we offer some considerations for optimizing these protocols.

Molecular basis for fungicidal action of neothyonidioside, a triterpene glycoside from the sea cucumber, Australostichopus mollis.

Neothyonidioside is a triterpene glycoside (TG) isolated from the sea cucumber, Australostichopus mollis, that is potently cytotoxic to S. cerevisiae, but does not permeabilize cellular membranes. We mutagenized S. cerevisiae and isolated a neothionidioside-resistant (neo(R)) strain. Using synthetic genetic array mapping and sequencing, we identified NCP1 as the resistance locus. Quantitative HPLC revealed that neo(R)/ncp1 mutants have reduced ergosterol content. Ergosterol added to growth media reversed toxicity, demonstrating that neothionidioside binds directly to ergosterol, similar to the polyene natamycin. Ergosterol synthesis inhibitors ketoconazole and atorvastatin conferred resistance to neothionidioside in a dose-dependent manner showing that a threshold ergosterol concentration is required for toxicity. A genome-wide screen of deletion mutants against neothionidioside revealed hypersensitivity of many of the component genes in the ESCRT complexes relating to multivesicular body formation. Confocal microscopy of cells stained with a vital dye showed blockage at this step. Thus, we propose neothionidioside may affect membrane curvature and fusion capability in the endosome-vacuole pathway.