Identify the unnecessary experimental details in the below Results segment.
Because Nocardia have a unique cell wall and membrane structure, drug permeability should not be overlooked. Growth inhibition can be tested employing the surrogate marker Nocardia asteroides, which has high genomic sequence similarity to that of N. brasiliensis. To test the inhibitor candidates from the in vitro assay, bacteria were grown overnight in LB broth to which 100mM glucose and 0.01% Tween20 had been added. (12) The surfactant Tween20 in the liquid medium allowed Nocardia to disperse. Different amounts (1, 5, 10, 15, and 50 µg/ml, respectively) of the five candidate molecules were added to LB broth containing agar, vortexed briefly to mix and then allowed to solidify. Media without any inhibitor candidate served as a negative control, and media with 50 µg/ml of kanamycin served as a positive control. Cultures were grown on solid agar overnight at 37° C.
We found that two out of the five candidate molecules clearly inhibited growth of bacterial cultures (data not shown). NB22 demonstrated 100% growth inhibition at 15 µg/ml, whereas NB20 inhibited growth only weakly at the same concentration. Bacterial growth on the negative control plate was not affected, and no growth was observed for the kanamycin treated plate (data not shown).