The fermentation culture of a soil strain of Streptomyces has been chemically investigated for its inhibitory activity against RNA polymerases from the bacteria Escherichia coli and Staphylococcus aureus. The active component was found to be the unusual bicyclodepsipeptide salinamide A (1) recently discovered from a marine Streptomycete. The same extract also yielded a new cyclohexapeptide natural product, desotamide (2), the structure elucidation of which was based on amino acid analysis, detailed spectroscopic data interpretation, and peptide synthesis.