Final answer:
To determine the presence of mycolic acid-rich cell walls in bacteria, the acid-fast staining technique is used, which highlights these cells in red. Mycoplasmas, which lack cell walls entirely, do not contain mycolic acids, and their identification relies on different methodologies.
Step-by-step explanation:
To identify whether a bacterial sample contains specimens with mycolic acid-rich cell walls, such as those in the genus Mycobacterium, the acid-fast staining procedure is employed. This method is necessary because the presence of the waxy mycolic acid in these bacteria prevents typical Gram staining from being effective. Instead, the acid-fast stain uses carbolfuschin, which stains acid-fast cells red, allowing them to be visualized against a contrasting background.
Mycoplasmas, on the other hand, lack a cell wall entirely and therefore do not contain mycolic acid. For these bacteria, their growth characteristics on selective media, resistance to certain antibiotics like penicillin due to the lack of a cell wall, and their pleomorphic shape aid in identification.
Mycolic acids are significant because they provide bacteria like M. tuberculosis and M. leprae with resistance to desiccation and contribute to the chronic nature of the diseases they cause, such as tuberculosis and leprosy.