Herbimycins D–F, Ansamycin Analogues fromStreptomyces sp. RM-7-15

Natalamycin A, an Ansamycin from a Termite-Associated Streptomyces sp.

We report a preliminary functional and complete structural characterization of a highly unusual geldanamycin analog, natalamycin A, that was isolated from Streptomyces strain M56 recovered from a South African nest of Macrotermes natalensis termites. Bioassay-guided fractionation based on antifungal activity led to the isolation of natalamycin A, and a combination of NMR spectroscopy and X-ray ...

Intramolecular proton transfer impact on antibacterial properties of ansamycin antibiotic rifampicin and its new amino analogues.

Intramolecular proton transfer in rifampicin (1) and its analogues 2-9 with the formation of zwitterions has been indicated by multinuclear NMR and crystallographic studies. Biological tests of 1-9 in combination with the analysis of ligand-protein interactions have revealed the relationship between the protonation site and extremely high antibacterial activity.

Topological superconductor in quasi-one-dimensional ${\rm Tl}_{2-x}{\rm Mo}_6{\rm Se}_6$

Metabolism of DDT analogues by a Pseudomonas sp.

A Pseudomonas sp. rapidly metabolized several nonchlorinated analogues of DDT, with the exception of 2,2-diphenylethanol, as the sole carbon source. Several of the mono-p-chloro-substituted diphenyl analogues were also metabolized as the sole carbon source by the bacterium. The resulting chlorinated aromatic acid metabolites were not further metabolized. The isolate was unable to metabolize p,p...

Identifying an Honest ${\rm EXP}^{\rm NP}$ Oracle Among Many

We provide a general framework to remove short advice by formulating the following computational task for a function f : given two oracles at least one of which is honest (i.e. correctly computes f on all inputs) as well as an input, the task is to compute f on the input with the help of the oracles by a probabilistic polynomial-time machine, which we shall call a selector. We characterize the ...