produced by unidentified oligosporic actinomycete strain No. E864-61; broad antibiotic spectrum against G+ & G- anaerobic bacteria; BU-2313 for both BU-2313 A & BU-2313 B; see also BU-2313 B; RN given refers to (2R-(2alpha,3alpha,3aalpha,5alpha(1R*,2E,4E),6beta,7alpha,9abeta))-isomer; structure given in first source