University of Michigan Museum of Zoology

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Three liquid nitrogen freezers chill at UMMZ


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Professor and Curator Priscilla Tucker’s Collections Improvement Grant was funded by the National Science Foundation for over $178,000 to purchase three large capacity liquid nitrogen freezers for frozen tissue storage.

The freezers arrived in November 2011. The isothermal freezers maintain a vapor storage temperature of -190 degree C. Each freezer can hold up to 40,300 2.0 ml cryogenic tubes. The freezers, materials and supplies cost $78,420. Interested parties will have a chance to tour the new facility at an open house during the Friday coffee hour, Dec. 9 at 11 a.m., Room 3088 Museums (note location change, this is where the freezers are located).

The Museum of Zoology (UMMZ) is an internationally recognized center of biodiversity research and teaching. It houses a large collection of animals and associated materials, representing all primary global ecosystems. Five of the six divisions (fishes, mollusks, herpetology, birds and mammals) maintain frozen tissue collections totaling over 36,500 specimens. They serve as an important source of genetic material for biodiversity research and are utilized by researchers from all over the world.

Prior to the acquisition of the new freezers, the specimens were maintained in six aging –80 C ultralow freezers located in separate areas of the museum. None of the freezers had a backup power supply in the event of a power failure. The lower temperature offered by the liquid nitrogen freezers coupled with a static holding time of eight days will ensure both higher quality and safer long-term storage of tissues. The new freezers are centrally located in newly renovated OSEH-compliant space located on the third floor of the UMMZ and are outfitted with remote contact alarms in case of malfunction.

In addition to the acquisition and installation of the liquid nitrogen freezers, the two-year project involves inventory and transfer of previously accessioned tissues from ultralow freezers to the new freezers, and accession and transfer of a backlog of frozen tissues. The proposed accessioning activities by all divisions will immediately result in increased use. Given that both curators and students use and deposit tissues at an increasing rate compared to the past, we expect that the size and use of the frozen tissue resource will continue to expand dramatically.

According to the grant proposal, in addition to serving as an important resource for biodiversity research, the UMMZ collections, including the frozen tissue resource, provide data that inform conservation practices and climate change research. As a center of biodiversity education, the UMMZ also has a teaching mission. Undergraduate students are an integral part of curatorial and research activities and they will actively participate in accessioning tissue for the new facility. Tucker, the principal investigator, and Steve Hinshaw, a collections coordinator, are currently working with Undergraduate Research Opportunity Program (UROP) student, Kelsey Libbe, to develop a special project page on the Animal Diversity Web, an educational biodiversity database. It will describe the liquid nitrogen storage facility, the need to store tissue at low temperature and give information on the kinds of biodiversity research that are possible using museum specimens including DNA isolated from the frozen tissue.

Photo: Kelsey Libbe, a student in the Undergraduate Research Opportunity Program, transfers boxes containing frozen tissues to one of three new liquid-nitrogen freezers at the Museum of Zoology.