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A series of chlorinated bisindole pyrroles, lynamicins A−E ( 1− 5), was discovered from a novel marine actinomycete, NPS12745, which was isolated from a marine sediment collected off the coast of San Diego, California. Close to full length 16S rRNA sequence analysis indicated that NPS12745 is a novel strain of a recently described marine actinomycete with the proposed genus name Marinispora.The antimicrobial spectrum of these compounds was evaluated against a panel of 11 pathogens, which demonstrated that these substances possess broad-spectrum activity against both Gram-positive and Gram-negative organisms. Significantly, compounds 1− 5were active against drug-resistant pathogens such as methicillin-resistant Staphylococcus aureusand vancomycin-resistant Enterococcus faecium. more...

Marine actinomycete strain NPS008920, a member of the new genus Marinispora, was isolated from a sediment sample collected in Cocos Lagoon, Guam. In natural sea water containing media, the strain produced a series of novel 2-alkylidene-5-alkyl-4-oxazolidinones, lipoxazolidinone A ( 1), B ( 2), and C ( 3). Compounds 1– 3showed broad spectrum antimicrobial activity similar to that of the commercial antibiotic linezolid (Zyvox), a 2-oxazolidinone. Hydrolysis of the amide bond of the 4-oxazolidinone ring of 1resulted in loss of antibacterial activity. The 2-alkylidene-4-oxazolidinone represents a new antibiotic pharmacophore and is unprecedented in nature. more...

The paraneoplastic syndrome of erythrocytosis is associated with a variety of neoplasms including renal adenocarcinoma, cerebellar hemangioma, and hepatoma. We now report the characterization of the biological and molecular features of an erythropoietin-secreting human renal adenocarcinoma, designated RCCEp+. Serial transplantation of the tumor in athymic mice resulted in a dramatic increase in hematocrit and serum erythropoietin concentration. Growth in vitrowas accompanied by a constant rate of erythropoietin secretion. Karyotype analysis demonstrated several unusual features, including the absence of 3p deletions and near tetraploidy. Erythropoietin mRNA was demonstrated by Northern blot both in freshly excised tumor and in tumor cells growing in vitro. Erythropoietin secretion was constitutive and was not induced either by cobalt or hypoxia. Southern blot analysis revealed no rearrangement of the erythropoietin gene in the tumor. Interestingly, in situhybridization demonstrated erythropoietin mRNA in only a small population of the tumor cells. Further studies of RCCEp+should prove useful in elucidating the molecular basis for this paraneoplastic syndrome. more...