What is a defining trait of Mycoplasma species in laboratory cultivation?

Mycoplasma species are unique among bacteria due to their lack of a cell wall, which is a defining characteristic of this genus. This absence of a cell wall makes them particularly pliable and allows them to adopt various shapes. In laboratory settings, Mycoplasma species are often cultured using specialized broth media that contain a rich nutrient base, since they cannot be grown on traditional solid media used for most other bacterial species.

The lack of a cell wall also contributes to their distinctive sensitivity to external environments, such as osmotic pressure changes, which makes them more challenging to cultivate compared to other bacteria that possess cell walls. This trait is crucial not only for their identification but also for the types of media and conditions that microbiologists must use to successfully cultivate them.

While Mycoplasma species do require oxygen for growth (they are aerobic or facultatively anaerobic), they do not require high oxygen levels as a defining feature. Additionally, the assertion that they cannot be cultured at all is incorrect; when proper conditions and media are provided, they can indeed be cultivated under lab settings.