Endospore - PP

Observation of a colony from the pasteurized plate, under a phase contrast microscope at 1000x, showed endospores inside rod shaped bacterium. The endospores were located primarily at the terminal end of the bacillus, and were seen as bright ovals with the darker bacterium surrounding them. This confirmed that the bacillus containing endospores survived pasteurization and was able to continue growing on the nutrient agar. Not all of the bacilli contained endospores, suggesting that the nutrients on the agar were substantial enough to inhibit sporulation. These bacilli grew in diplobacillus and streptobacillus arrangements. A Gram stain of the same colony used for microscopy showed that the endospore forming bacilli were gram positive based on the dark purple color of the bacterium. The endospores were not stained and appeared as clear ovals at the terminal ends of the bacterium. This Gram stain confirmed that the bacterium that formed the endospores were Gram positive. Also, the Gram stain showed that the thick layer of proteins and peptidoglycan surrounding the endospore had not been damaged and was able to keep the stain and water out of the endospore.