Drigalski spatula
The Drigalski spatula , named after its inventor Wilhelm von Drigalski , is used for the uniform application of one- to few-cell microorganisms on an agar plate . The spatula is made of glass or metal.
application
In order to distribute only the intended microorganisms on the agar plate , the spatula must be sterilized before use . This happens through the action of ethanol and heat. To do this, the spatula is kept in a beaker with at least 70% ethanol and before each use it is flamed once or twice in the flame of a gas burner ( e.g. Bunsen burner or Teclub burner ). To cool down, the Drigalski spatula can first be pressed on the edge of the agar plate for a few seconds. If the spatula is not cooled down sufficiently, the microorganisms to be distributed on the agar plate will be killed.
The microorganism suspension placed in the middle of the agar plate using a pipette or an inoculation loop is evenly distributed with the cooled spatula using circular movements. The Petri dish in which the agar plate is located is conveniently held with one hand while the other hand writes an 8 with the spatula. The Petri dish should be rotated by hand. The spatula continues until the spatula no longer slides easily. The smaller the volume applied and the drier the agar plate used, the faster this happens.
Alternatives
Instead of the Drigalski spatula, sterile glass beads can also be used.
literature
- Alexander Steinbüchel, Fred B. Oppermann-Sanio: Microbiological internship: experiments and theory; with 106 tables . Springer, Berlin, Heidelberg 2003, ISBN 3-540-44383-5 .