Other tested strains, namely, S. aureus ATCC 25923 and B. subtilis CGMCC 1.1470, were resistant to elgicins. Table 2 Antibacterial spectra of RP-HPLC-purified elgicin see more compounds Indicator Strain Diameter of Inhibition (mm)   Elgicins a Polymyxin B b Staphyloccus epidermidis

CMCC 26069 8 18 Staphylococcus aureus ATCC 43300 8 15 Staphylococcus aureus ATCC 25923 0 0 Bacillus subtilis CGMCC 1.1470 0 10 Pseudomonas aeruginosa ATCC 27853 7 12 Escherichia coli ATCC 35218 9 10 Proteus vulgaris CMCC 49027 8 0 aThe amount of elgicins is 150 μg per disk. bThe amount of polymyxin B is 30 μg per disk. Conclusions Genomic sequence analysis of Paenibacillus elgii B69 showed a novel lantibiotic-like gene cluster. Four new lantibiotics, designated elgicins AI, AII, B, and C, were isolated from the KL

medium. To the best of our knowledge, elgicins B and C are the largest reported lantibiotics to date, with molecular weights of 4706 and 4820 Da, respectively. Elgicins have broad inhibitory activities against several Gram-positive and Gram-negative bacteria. Further studies are required to determine their structures, identify their mechanisms of action, and find suitable bioprocessing strategies for efficient elgicin production. Methods Bacteria and culture CH5424802 in vitro conditions P. elgii B69 was isolated from a soil sample collected from Hangzhou, China [19]. Nutrient broth was routinely used for culturing P. elgii B69 at 30°C for 24 h. The active substances were produced in synthetic medium (KL). About 25 mL of the P. elgii B69 culture was used to inoculate 2-L conical flasks, each containing 500 mL of KL medium. Four other fermentation media, Landy medium (20 g/L glucose, 5 g/L L-glutamic acid, 0.5 g/L MgSO4, 0.5 g/L KCl, 1 g/L KH2PO4, 0.15 mg/L Fe(SO4)3·6H2O, 5.0 mg/L MnSO4·H2O, and 0.16 mg/L CuSO4·5H2O) [34], MYPGP broth (15 g/L yeast extract, 10 g/L Mueller-Hinton broth, 2 PtdIns(3,4)P2 g/L glucose, 3 g/L K2HPO4, and 1 g/L sodium pyruvate) [35],

AK medium (0.5 g/L asparagine, 0.5 g/L K2HPO4, 0.2 g/L MgSO4, 0.01 g/L FeSO4·7H2O, and 10 g/L glucose), and Luria-Bertani (LB) medium, were used to test for the presence of inhibitory factors. The fermentation batches were incubated aerobically on a shaker (200 rpm) at 30°C for 120 h. The test strains used to determine sensitivity to elgicins included S. epidermidis CMCC 26069, S. aureus ATCC 43300, S. aureus ATCC 25923, B. subtilis CGMCC 1.1470, P. aeruginosa ATCC 27853, E. coli ATCC 35218, and P. vulgaris CMCC 49027. P. ehimensis, a closely related species of P. elgii, was used as the indicator strain. All test stains were grown in nutrient broth or nutrient agar plates at 37°C. For stock preparation, the cells were cultivated for 24 h, mixed with sterile glycerol (to a final concentration of 25%, v/v), and stored at -80°C. Bioinformatic analyses Using the modification enzyme SpaC of P.