Spontaneously occurring bacterial transformations in mice

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Deoxyribonucleic acid (DNA)-mediated transformation in pneumococci was first reported in 1963.
• Spontaneous transformation occurs between genetically distinct pneumococci within a host.
• The natural occurrence and frequency-modulating factors of in vivo transformation require further investigation.

Purpose of the Study:

• To investigate factors influencing the frequency of in vivo DNA-mediated transformations.
• To explore interspecific transformations between different bacterial species.
• To assess the likelihood of natural DNA-mediated transformations.

Main Methods:

• Infection of mice with two genetically distinguishable pneumococcal strains.
• Treatment of infected animals with a selective drug targeting one strain.
• Prolonging the duration of infection.
• In vitro and in vivo co-cultivation of pneumococci and streptococci without purified DNA.

Main Results:

• Selective drug treatment significantly increased the frequency of in vivo transformations.
• Prolonged infection duration also led to a higher frequency of in vivo transformations.
• Interspecific transformation between pneumococci and streptococci was observed without added DNA.

Conclusions:

• Factors such as selective pressure and infection duration can enhance in vivo bacterial transformation.
• Bacterial transformation can occur between different species, even without purified DNA.
• The findings support the hypothesis that DNA-mediated transformations are a natural biological phenomenon.