Mycoplasma mycoides

Mycoplasma mycoides subsp. capri str. GM12 is a genomically simple bacterial pathogen of ruminant livestock. It possesses a single plasma membrane, no cell wall, and minimal lipid biosynthetic capacity — properties that make it an ideal model for studying membrane biology and the parent organism from which the B minimal cells were derived.

As a Membrane Model

Mycoplasmas were recognized as minimal living membrane models as early as the 1960s. Their key advantages:

• Single plasma membrane: no outer membrane, no cell wall — membrane properties can be examined in situ without purification.
• Limited lipid synthesis: most lipids are acquired from growth media, enabling external control of lipidome composition.
• Simple lipidome: tens of species (not hundreds), amenable to comprehensive quantitative lipidomics.

Our Work with M. mycoides

• Lipidome minimization: we showed that M. mycoides can survive with a two-component lipidome (cholesterol + one phospholipid), and that acyl chain diversity matters more than head group diversity for growth (Justice et al., 2024, Nature Communications).
• Temperature adaptation: shotgun lipidomics revealed lipidome flexibility with a two-stage cold adaptation process — rapid cholesterol/cardiolipin shifts followed by gradual acyl chain remodeling (Safronova et al., 2024, Cell Reports).
• Viscosity measurements: we detected a lipid phase transition in M. mycoides using our DCVJ plate reader method (Chwastek et al., 2019, ChemBioChem).
• Chemically defined lipid diets: cyclodextrin-mediated delivery of defined lipid species produces lipidomes with 7–30 species (Safronova et al., 2024, bioRxiv).