Phylogeography of the fungal pathogen Histoplasma capsulatum.

Until recently, Histoplasma capsulatum was believed to harbour three varieties, var. capsulatum (chiefly a New World human pathogen), var. duboisii (an African human pathogen) and var.

Viability of and plasmid retention in frozen recombinant Escherichia coli over time: a ten-year prospective study.

The long-term viability and plasmid retention of recombinant Escherichia coli strains were investigated by real-time testing of master cell banks (MCBs) stored at the Roche Molecular Systems Culture Collection (RMSCC). MCBs at the RMSCC were cryogenically frozen and stored at -80 degrees C for long-term preservation. At regular intervals during a period of 5 to more than 10 years, representative cryovials of each MCB were tested for viability and plasmid retention.