In vitro spheroplast and L-form induction within the pathogenic nocardiae

Area of Science:

• Microbiology
• Bacteriology

Background:

• Nocardia species are Gram-positive bacteria known for their complex cell wall structures.
• Understanding mechanisms of cell wall modification is crucial for antimicrobial development.

Purpose of the Study:

• To investigate the formation of spheroplasts and L-forms in Nocardia species under specific growth conditions.
• To evaluate the differential responses of Nocardia strains to cell wall-compromising agents.

Main Methods:

• Culturing Nocardia asteroides, N. caviae, and N. braziliensis strains in media supplemented with glycine, lysozyme, and/or D-cycloserine.
• Utilizing phase contrast and electron microscopy to observe morphological changes.
• Isolating and culturing L-forms on hypertonic media.

Main Results:

• Three N. asteroides strains and two N. caviae strains readily formed spheroplasts/protoplasts when exposed to glycine combined with lysozyme or D-cycloserine.
• Significant variability was observed among strains in their ability to generate spheroplasts.
• Successful isolation of L-forms and transitional-phase variants from induced cultures.

Conclusions:

• Glycine in combination with lysozyme or D-cycloserine effectively induces spheroplast and L-form formation in susceptible Nocardia strains.
• Strain-specific differences in cell wall composition or repair mechanisms influence susceptibility to these agents.
• The study highlights the potential for generating cell wall-deficient variants in Nocardia, relevant for studying bacterial morphology and potential therapeutic strategies.