Policies, Procedures, and Equipment.
Acknowledgment and citing the CryoEM Core
Please acknowledge the contributions of our staff and the use of our core facility in your publications.
- “We acknowledge Emily Robinson and Dr. Joshua Strauss of the UNC CryoEM Core Facility for technical assistance in this project”
- “Data was collected at the UNC at Chapel Hill CryoEM Core Facility with a 200 keV Thermo Fisher Scientific Talos Arctica equipped with a Gatan K3 direct electron detector”.
We offer fee-for-services for (1) cryo-grid sample preparation using a Vitrobot Mark IV, (2) Screening and Data collection using Talos Arctica CryoTEM. Booking equipment and billing are done in iLAB, make sure to have an account set up before using the CryoEM Core. If you would like to learn how to operate the Vitrobot and Talos Arctica, please contact the Core Directory directly and request training.
Pre-processing of single-particle cryoEM data, including motion correction and CTF estimation using Warp or CryoSPARC Live, is not considered “image processing” and is typically included in the data collection. Anything beyond this is considered image processing, including 2D classification and EM map generation. Having the ability to process data on the fly is incredibly useful, and we routinely will generate 2D class averages and 3D models to determine the structure of the target complex as it is being collected. If you need assistance with this, we are happy to help, we only ask that you acknowledge the CryoEM Core Staff that process the data. Image processing can be done during data collection and typically takes a few hours to complete.
Operation of the Vitrobot
Only trained users are permitted to operate the Vitrobot. The Vitrobot is located in Glaxo Research Building room 011 across the hall from the Talos Arctica. The Vitrobot Mark VI can be reserved using iLAB. If you need assistance or require training please contact us directly.
Operation of the Talos Arctica
The Talos Arctica is used for cryo-EM specimen screening and high-resolution data collection. Only trained users are permitted to operate the Talos Arctica. Researchers interested in getting trained or using the microscope, please contact the cryo-EM core director Dr. Joshua Strauss. Only cryoEM core staff are allowed to dock/undock the cassette into the Autoloader and load/unload grids into the cassette. We limit the number of docking/undockings to two per day and only during working hours of the core 9AM-7PM. We typically schedule two sessions per day, M-F. The morning session, 9AM-2PM, is only for screening samples with the option to collect a small data set of up to 1000 movies (about 2 hours of data collection). The evening session, from 2PM-7PM, is for either (1) screening samples with the option to collect ~5,000 movies overnight, or (2) for collecting data overnight. If you require a dataset larger than 5000-6000 micrographs, data can also be collected over the weekend. We will typically load the sample Friday afternoon and monitor data collection remotely.
Each core user is responsible for the long-term storage of their data. Data collected from the Gatan K3 camera is stored in the Dogwood/Longleaf research computing cluster, where it can be accessed via Globus. We do not offer long-term storage (> 3 months) for data collected on the Talos Arctica TEM. Additional information about the Dogwood and Longleaf computer clusters are on the UNC Research Computing website https://its.unc.edu/research-computing/techdocs/longleaf-frequently-asked-questions-faqs/
Storage of Cryogrids
Core users can store cryo-grids in the Biocane34 liquid nitrogen dewar located in the cryo-prep room at Glaxo Research building. The cryoEM core maintains a record of the samples stored in this dewar, however, we encourage people to keep a duplicate record of the location of their samples. Only cryoEM core staff are permitted to remove and place samples in the Biocane34 dewar. Each lab is allowed one puck to store their cryo-grids. If you need more than one puck, contact the Core Director.