Sterile cork borer

The solution is placed in contaet with agar, which is already inoculated with the test organism and after ineubation zones of inhibition observed. The solution may be placed in a small eup sealed to the agar surfaee (a method used widely in anhbiotic assays) in a well cut from the agar with a sterile cork-borer, or applied in the form of an inpregnated disc of filter paper (Fig. 11.5 A). 

In this method, 25 ml of a molten sterile medium is poured into presterilised Petri dishes and allowed to solidify at room temperature (RT). The agar plates are seeded with 0.1 ml of (1 X 10 spores/ml) of a fungal/bacterial culture using the spread plate method. Subsequently, 10 mm wide wells are bored into these agar plates using a sterile cork borer. 250 pi of a stock solution of an antimicrobial compound is filled into the wells and the plates are incubated at 25 2 °C. The antimicrobial activity is interpreted from the size of the zone of inhibition(s) (ZOI) measured to the nearest millimetre, i.e., the clear zones surrounding the wells, as shown in Figure 11.1 [20-23]. 

Pith tissue was removed with a cork borer, sectioned, sterilized, and placed on the media. Callus induced on one medium was subsequently subcultured on the same medium at eight-week intervals. Subcultures were so designated. 

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