I've been reading the classics - papers on Haemophilus influenzae competence and transformation published in the 1960s. They contain lots of information that, if true, is important for our work. But we know it's all too easy to 'discover' things that turn out to not be true, so we'll need to proceed cautiously.
Here are some factoids that contradict my current assumptions:
The media additive hemin loses potency after for a few weeks in the fridge . (We've been keeping it for years.)
Washing competent cells removes one or more factors needed for DNA uptake.
Cells have a nucleoside phosphorylase that is active in the periplasm - this means it acts on nucleosides that haven't been taken up by the cell yet. This may be important for understanding why purine nucleotides and nucleosides inhibit competence but purine bases don't.
Cells bind about five times more DNA than they take up.
32 minutes ago in Variety of Life