Mercury-in-glass thermometer Mercury-in-glass thermometer The mercury-in-glass or mercury thermometer was invented by physicist Daniel Gabriel Fahrenheit in Amsterdam (1714). It consists of a bulb containing mercury attached to a glass tube of narrow diameter; the volume of mercury in the tube is much less than the volume in the bulb. The volume of mercury changes slightly with temperature; the small change in volume drives the narrow mercury column a relatively long way up the tube. The space above the mercury may be filled with nitrogen gas or it may be at less than atmospheric pressure, a partial vacuum. In order to calibrate
IbpB thermometer IbpB thermometer The IbpB thermometer is an RNA thermometer element found in the "ibpAB" operon. The operon contains two heat-shock genes, encoding inclusion body binding proteins A and B (IbpA/B), and is the most drastically upregulated operon under heat-shock in "Escherichia coli". "IbpA" is regulated by a ROSE element found in its 5' UTR, while "IbpB" has its own heat-sensitive cis-regulatory element. The activity of this thermoregulator was confirmed "in vitro" but was not found "in vivo", suggesting more complicated operon regulation exists in bacterial cells. The IbpB protein, whose expression is regulated by the IbpB thermometer, is 48% identical