Usage and Billing
For any new projects the Project proposal form must be filled out and signed. A copy of the form will be emailed to the facility managers, user and their PI. For any biohazardous samples, the protocol must first be approved by the Biosafety committee. The copy of biosafety protocol must be forwarded to managing directors.
Superusers may sign up for microscope time independently. Non-superusers must identify a superuser or Director who will help them with that session.
Due to high number of images necessary for a single particle reconstruction and a tomographic exploration, the minimum sign up time for the Arctica and the Krios is 1 day. Each one day session is from 9 am to 9 am of the following day. Users are required to remove their grids by 9 am to allow for a smooth transition for the next user. The maximum session length on the Arctica and the Krios is 2 days. Under extenuating circumstances (very heterogeneous sample, etc.), longer sessions can also be approved. Please contact staff to discuss the possibilities. To allow for an equal access to the facility’s resources, a user can only sign up for a single session at a time. Reservations can only be made up to a month ahead of the current date. Any cancellations must be made at least 24 hours in advance of the session.
Every Monday on the Arctica is designated as a “Flex” day. The primary uses for this day are 1) for emergency collection or to make up a collection day due to unexpected microscope down time and 2) as a screening day. For screening, two 4 hour sessions can be reserved: 9 am – 1 pm, 1 pm – 5 pm. Independent users could set up an overnight collection from 5 pm to 9 am the following morning. Please be prompt in removing your grids Monday morning before 9 am and/or at the end of your screening session. The sessions on Mondays will not contribute to your reservation count.
It is expected that before single particle project users sign up for time on the Arctica, they will optimize new samples through negative stain imaging on the T12 until the particles are (1) monodisperse, (2) abundant, and (3) classify into nice 2D classes (evidence of structural stability). All cryo-sample optimization should be done on the Arctica, including at least one full reconstruction. This step will reveal whether the particles resolve into clear class averages (hopefully with visible secondary structure) AND that orientation preferences are overcome.
Tomography samples should be optimized on the Arctica until the (1) target abundance, (2) ice quality, and (3) number of fiducials per field of view are all suitable. Cryo-FIB’ed lamella, cryosections, and grids that have already been imaged by cryo-fluorescence microscopy can all go directly to the Krios.
Every user, regardless of the hazard level of their sample, should be prepared to discuss:
- Preliminary risk classification/assessment for the material they are bringing
- Best cleaning / disposal practices
- Best handling practices
- Minimum infectious and lethal doses
- For infectious agents:
- Rates of survival on various surfaces
- Preferred areas to infect
- Transmission source / routes of exposure
- Types of infections caused
- Symptoms and incubation time
- Types of treatment available
This information and any specific procedures necessary for the safe handling of the sample must also be provided to facility managers.
The Center maintains all cryo-EM tools and supplies except for grids. Due to many options for kinds of grids and necessary careful storage and handling, individual labs must plan in advance and provide their own grids. Some standard grids will be available at the Chemistry stockroom in BI.
Due to the complexities of the instruments, user error, or unforeseen circumstances unplanned outages do occur, potentially interrupting user’s session. When this occurs, the billed usage will be rounded to the nearest half-day. Further, due to complexities of trying to shuffle everyone when outages occur, any user with an interrupted session would have to sign up for a new session at the next available time.
Sample and Data Storage policies
Cryo-EM facility is a shared space open to all of Caltech researchers. Each user must return shared resources to their designated location as soon as possible. We can provide a short term space in the 4°C and -80°C fridge and freezers, as well as cryo specimen dewars. Each users trained in freezing will be allocated a single puck (12 grid boxes) for sample storage. Shared spaces will be regularly cleaned out and it is user’s responsibility to adequately label and store samples and reagents in order to prevent any accidental discharge of the material during cleaning.
Please provide the following statement in any publications that used center resources:
“(Cryo) Electron microscopy was done in the Beckman Institute Resource Center for Transmission Electron Microscopy at Caltech. “
Please send citation to any paper that utilized center resources to facility mangers as soon as it is published.