Four new analogues of concanamycin family, designated concanamycins D, E, F and G, were isolated from the mycelium of Streptomyces sp. A1509by solvent extraction, silica gel column chromatography and HPLC.Structures of these compoundswere identified by the combination of spectroscopic analyses. All of these compoundswere structurally related to concanamycinsA, B and C, which had been isolated previously, and inhibited the acidification of rat liver lysosomes at 10~1 2^-10~9 mconcentration. The structure-activity study showedthat the 18-memberedmacrolide ring and the 6-membered hemiketal ring portions of the molecules of concanamycin family are responsible for potent inhibitory activity.
Abstract. We study unbounded invariant and covariant derivations on the quantum disk. In particular we answer the question whether such derivations come from operators with compact parametrices and thus can be used to define spectral triples.
A sesquiterpene named koningic acid has been isolated from a strain of Trichoderina koningii as a potent inhibitor of ATP generation in the glycolytic pathway. From experiments with both cultured mouse carcinoma FM3A cells and isolated enzymes, it was shown that koningic acid is a specific inhibitor of glyceraldehyde 3-phosphate dehydrogenase that
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