Project description:Streptomonospora sp. M2 has been isolated from a soil sample collected at the Wadden Sea beach in our ongoing program aimed at the isolation of rare Actinobacteria, ultimately targeting the discovery of new antibiotics. Because crude extracts derived from cultures of this strain showed inhibitory activity against the indicator organism Bacillus subtilis, it was selected for further analysis. HPLC-MS analysis of its culture broth revealed the presence of lipophilic metabolites. The two major metabolites of those were isolated by preparative reversed-phase HPLC and preparative TLC. Their planar structures were elucidated using high-resolution electrospray ionization mass spectrometry (HRESIMS), 1D and 2D NMR data as new thiopeptide antibiotics and named litoralimycin A (1) and B (2). Although rotating frame nuclear Overhauser effect spectroscopy (ROESY) data established a Z configuration of the Δ21,26 double bond, the stereochemistry of C-5 and C-15 were assigned as S by Marfey's method after ozonolysis. The biological activity spectrum of 1 and 2 is highly uncommon for thiopeptide antibiotics, since they showed only insignificant antibacterial activity, but 1 showed strong cytotoxic effects.
Project description:Background: Ependymomas encompass multiple, clinically relevant tumor types based on localization and molecular profiles. Although tumors of the methylation class “spinal ependymoma” (SP-EPN) represent the most common intramedullary neoplasms in children and adults, their developmental origin is ill-defined, molecular data are scarce, and the potential heterogeneity within SP-EPN remains unexplored. The only known recurrent genetic events in SP-EPN are loss of chromosome 22q and NF2 mutations, but neither types and frequency of these alterations nor their clinical meaning have been described in a large, epigenetically defined series. Methods: We mapped SP-EPN transcriptomes (n=76) to developmental atlases of the developing and adult spinal cord to uncover potential developmental origins of these tumors. In addition, transcriptomic, epigenetic (n=234), genetic (n=140), and clinical analyses (n=115) were integrated for a detailed overview on this entity. Results: Integration of transcriptomic ependymoma data with single-cell atlases of the spinal cord identified mature adult ependymal cells to display highest similarities to SP-EPN. Unsupervised hierarchical clustering of tumor data together with integrated analysis of methylation profiles identified two molecular SP-EPN subtypes. Subtype 1 predominantly contained NF2 wild type sequences with regular NF2 expression but revealed more extensive copy number alterations. Subtype 2 harbored previously known germline or sporadic NF2 mutations and was NF2-deficient in most cases, more often showed multilocular disease, and demonstrated a significantly reduced progression-free survival. Conclusion: Based on integrated molecular profiling of a large tumor series we identify two distinct SP-EPN subtypes with important implications for genetic counseling, patient surveillance, and drug development priorities.
