Previously called the Tissue Culture Module, this unit evolved into a inclusive facility providing expertise and resources such as tissue culture cell lines, bacteria, plasmids, viruses, and other biologicals that are maintained at the appropriate storage temperatures (usually in liquid nitrogen or in ultra-low temperature freezers with CO2 backup), which participating investigators may draw upon as needed. An experienced technician who is supervised by the Module directors maintains the facility and the equipment housed within the Module such that the participating investigators can access these facilities at any time. With the expansion of this Module to include cellular and molecular biology, facilities and equipment within it include, in addition to the tissue laminar flow hoods and incubators, equipment such as thermal cyclers, hybridization ovens, and gel imaging and documentation systems, as well as liquid nitrogen storage and ultra-low temperature freezers with CO2 back-up.[unreadable]