Properties of a transmissible plasmid conferring citrate-utilizing ability in Escherichia coli of human origin

In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...

Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...

Conjugation is a form of horizontal gene transfer that primarily occurs in bacteria and some archaea, promoting genetic diversity and adaptation. Bacteria can acquire resistance genes through conjugative plasmids, allowing them to survive antibiotic treatments that would otherwise be lethal. This process involves direct contact between cells through specialized structures such as the sex pilus and is mediated by conjugative plasmids, including the F (fertility) factor.Conjugation requires...

Bacterial conjugation is a mechanism of horizontal gene transfer that enables the exchange of genetic material between bacterial cells through direct contact. This process is facilitated by a donor cell carrying a conjugative plasmid, which encodes genes necessary for pilus formation, DNA replication, and transfer. The conjugative plasmid plays a central role in initiating and executing the transfer of genetic material.The tra region of the conjugative plasmid encodes proteins responsible for...