THE TRANSFORMATION IN VITRO OF R PNEUMOCOCCI INTO S FORMS OF DIFFERENT SPECIFIC TYPES BY THE USE OF FILTERED...

Area of Science:

• Microbiology
• Bacteriology
• Genetics

Background:

• Pneumococci exist in virulent (S) and avirulent (R) forms.
• Understanding the transformation of R pneumococci to S forms is crucial for microbiology.

Purpose of the Study:

• To investigate the transformation of avirulent R pneumococci into virulent S pneumococci.
• To identify the specific factors responsible for this transformation.

Main Methods:

• Avirulent R pneumococci were cultured in a broth containing anti-R serum.
• A heated, filtered extract from virulent S pneumococci of different types was added.
• The transformation of R strains derived from Type II pneumococci using extracts from Type I and Type III S forms was specifically examined.

Main Results:

• Avirulent R pneumococci were successfully transformed into virulent S pneumococci.
• The transformed S organisms were identical in type to the bacteria used in the extract.
• The extract constituents provided a specific stimulus, enabling R pneumococci to produce capsular material characteristic of the extracted S forms.

Conclusions:

• Specific components within S pneumococcal extracts can induce the transformation of avirulent R pneumococci into virulent S forms.
• This transformation involves the acquisition of type-specific capsular material elaboration by the R pneumococci.
• The findings highlight a mechanism for genetic transformation in pneumococci.