Conversion of the Genetic Resources Collection to Liquid Nitrogen Preservation
The Genetic Resources Collection (GRC) of the NSRL contains more than 350,000 tissue samples from more than 98,000 individuals representing approximately 1,100 species of mammals and other taxa. It is among the largest, fastest growing, and most utilized collection of its kind. These samples are used by researchers from around the world to address questions vital to science and society, such as advancing our understanding of global biodiversity, the impact of humans and their activities on the natural world, and the transmission of disease between wildlife and humans. Each tissue sample is unique and irreplaceable, as it represents an individual at a specific point in time and space. The samples are of unlimited actual and potential value to the science community in terms of on-going and future research. It is crucial that these tissues be preserved at the highest standards to ensure their long-term availability for maximum scientific research potential and discovery.
Since its establishment in the 1970’s, the GRC had relied upon traditional -80oC mechanical freezers for storage of the GRC’s frozen samples. However, these freezers have a short lifespan and are subject to frequent malfunction or complete failure, as well as to power outages, thus putting samples at risk for degradation or total loss. More importantly, current and developing scientific disciplines require that tissue samples be preserved at temperatures below -132oC to preserve the entire spectrum of genomic data they contain (e.g., RNA, viruses, bacteria). Storage in liquid nitrogen (LN), which maintains samples near -190oC, thus has become the “gold standard” for preservation of tissue collections.
In 2015, Dr. Robert D. Bradley (Director of the NSRL) and Dr. Robert J. Baker (Former Director of the NSRL, now retired) received a grant from the Collections in Support of Biological Research program of the National Science Foundation (NSF) to transfer the frozen tissues of the GRC from the mechanical -80oC freezers to vapor-phase liquid nitrogen freezers in order to ensure the collection’s long-term preservation and availability for scientific research.
The 3-year project will include the transfer of all frozen tissue vials to stainless steel boxes with polypropylene cell dividers. This process of transferring tissues to new boxes and installation in the LN freezers will be time and labor intensive, but will allow for confirmation and updating of the GRC’s existing inventory of the tissue collection, as well as the upgrading of some vials with new label stock and barcodes (as needed). Dr. Caleb Phillips (Curator of the GRC) is incorporating the best museum practices in tissue archival and database methodologies as this transition takes place.
Other outcomes of this project will include: expanded storage capacity of the GRC, allowing for growth of the collection; annotation of the NSRL public database with genetic sequence database numbers; annotation of the NSRL’s internal database to indicate samples obtained from virus-positive vouchers and designation of those samples with color-coded labels; labeling of symbiotype and holotype genetic samples with color-coded labels; education and training of graduate and undergraduate students in collection management practices; a public exhibit highlighting the significance of genetic resource collections to science and society; outreach materials for high school educators; testing of cryolabels and other archival supplies; and reduced energy consumption by the transition to a green technology.
August - December 2015: The GRC facility was fully renovated to accommodate the LN system and to upgrade the overall facility. TTU provided the funding for the renovations of the GRC facility, as well as the purchase of two of the five LN freezers necessary to house the entire frozen tissues inventory and allow for growth of the collection.
January 2016 - present: Five Taylor-WhartonTM LABS freezers, supplied with liquid nitrogen via an exterior bulk tank and vacuum-jacketed piping, were installed. Initially, 3 of the 5 freezers were filled with liquid nitrogen; others will be filled and put to use as needed. With the assistance of Museum Science graduate students hired with NSF funds, the process of inventorying the collection, re-labeling vials (as needed), transferring samples to new boxes, and installing them into the LN freezers is in progress.