FAQ - Dicty Stock Center


Frequently Asked Stock Center Questions


    Questions regarding orders, deposits and shipping

  1. How do I order strains and/or plasmids from the Stock Center?
  2. Are there any recommended axenic wild type strains?
  3. What is the cost of each stock ordered from the Stock Center?
  4. How do I pay for shipping costs for items ordered from the Stock Center?
  5. How can I find out how much shipping will cost?
  6. Can I get a receipt for shipping?
  7. Can I get a receipt for ordered Stock Center items?
  8. How will I know when my order is being shipped?
  9. I ordered a strain several days ago, and have not yet received it; what should I do?
  10. Do you ship to for-profit organizations?
  11. How can I expect to receive ordered strains/plasmids from the Stock Center?
  12. How do I deposit strains/plasmids to the Stock Center?
  13. Lab and Technical questions

  14. How do I store the plasmid received, streaked out on an LB agar plate?
  15. How do I grow the plasmid received, streaked out on an LB agar plate?
  16. How do I prevent contamination of my Dictyostelium culture?
  17. At what temperature do dicty cells grow?
  18. What do I do with a strain received that is growing on an agar plate on a bacterial lawn?
  19. How do I make a bacterially grown strain axenic?
  20. What kind of bacteria are used as food source for Dictyostelium?
  21. How do I store a strain received that is growing on an agar plate on a bacterial lawn?
  22. What do I do with a strain received that is growing in liquid HL5 medium?
  23. How do I store a strain received growing in liquid HL5 medium?
  24. Is trypsin or similar necessary to detach cells from the bottom of a petri dish?
  25. How do I 'clean up' a contaminated strain?

This section will answer commonly asked questions about the Dicty Stock Center. For further technical information please consult the Techniques page; for information about orders, the Order Info page; for information about deposits, the Deposits page.


  1. How do I order strains and/or plasmids from the Stock Center?
    You can either select items from one of our three catalogs under the 'Stock Center' Tab, or you can search for items by going to the Stock Center Search page. You can also add items from the Phenotype and Strain Details page for strains, by clicking on the green shopping cart. You can then review the items in your cart and proceed to check-out when you are finished.

  2. Are there any recommended axenic wild type strains?
    If no specific axenic strains are required for your research, we recommend the following strains: AX4 (DBS0237637; the sequenced strain), AX3 (DBS0235539), and AX2-214 (DBS0235534).

  3. What is the cost of each stock ordered from the Stock Center?
    Items cost between $ 15.- and $ 40.- for customers from non-profit institutions. Click here for complete price info. In addition, you will be required to pay for the shipping costs associated with your order.

  4. How do I pay for shipping costs for items ordered from the Stock Center?
    When you have added all items to your shopping cart, click 'Check out' and you will be required to fill in your shipping information as well as how you will pay for the shipping. You will have the option to select either 'FedEx' or 'UPS' and supply the appropriate account number (please make sure you supply a valid account number). If you do not have an account number with either of these suppliers, you can select 'Telephone in Credit Card information' in which you can call into the Stock Center and provide a valid credit card to cover the shipping charges. Additionally, if you have for example a DHL account number, you may also use that by just adding a note in the 'Comments/Special Instructions' field on the order page.

  5. How can I find out how much shipping will cost?
    You can call your local FedEx, UPS, or DHL office and ask about the exact shipping charges. The Stock Center cannot provide this information because we do not charge you for shipping ourselves, and some shipping account numbers may have prior university discounts set up, etc. In general, for national orders, we will ship 'Priority Overnight', and for international orders, we will ship 'International Priority'.

  6. Can I get a receipt for shipping?
    The Stock Center cannot provide a shipping receipt because we do not charge for shipping. Contact your shipping company to request a receipt by referencing the order tracking number. The Stock Center cannot obtain these receipts as we are not privy to charges on other people's shipping accounts or credit cards.

  7. Can I get a receipt for ordered Stock Center items?
    Yes, since now stocks incur a charge. See cost and and payment info here. A receipt will be provided for all payed orders.

  8. I ordered a strain several days ago, and have not yet received it; what should I do?
    The Stock Center aims to ship orders within a week; however, not all items grow at the same rate. If your order does take longer than the average week, you will receive an email from the Stock Center regarding the status of your order.

  9. Do you ship to for-profit organizations?
    We do not ship to for-profit organizations unless you sign an agreement stating that the materials will be used for your own research.

  10. How can I expect to receive ordered strains/plasmids from the Stock Center?
    Strains will be typically shipped growing on an LPB or a GYP agar plate on a bacterial lawn. Occasionally you will receive a strain growing in liquid HL5 medium; in this case you will be notified prior to receiving the strain from the Stock Center. If growth in HL5 is desired, users must alert the DSC at the time of order. Plasmids will be shipped to you as bacterial transformants growing on an LB+drug plate (as applicable). You can find out what bacterial strain carries the plasmid by looking over your confirmation email-it will appear next to the plasmid name.

  11. How will I know when my order is being shipped?
    If you have an account already set up with FedEx, UPS, or DHL, you will automatically receive an email from them when your order ships along with the tracking number, etc. If you provided a credit card to cover the shipping charges, the Stock Center will send you an email with the tracking number when the FedEx waybill is being completed.

  12. How do I deposit strains/plasmids to the Stock Center?
    Please contact the Stock Center so that we will know what to expect and when. Fill out the forms available from our Deposits page (request a bulk form for large submissions). We will provide you with our FedEx account number to cover the shipping charges.

  13. How do I store the plasmid received, streaked out on an LB agar plate?
    Pick 2 colonies into a tube containing 4mL LB medium + drug (if appropriate) and grow overnight in a shaker set at 37°C. The next day, place the culture on ice and transfer 3mL into a new tube. Add 1.2mL sterile 75% glycerol and vortex gently, but mix thoroughly. Distribute 1mL into each of 4 pre-labeled and pre-cooled tubes. Store at -80°C.

  14. How do I grow the plasmid I received, streaked out on an LB agar plate?
    You may pick a bacterial colony from the shipped plate and streak it onto a fresh LB agar plate + drug (if appropriate). Place this fresh plate into an incubator set at 37°C overnight. The following day, pick colonies from the fresh plate and inoculate cultures to prepare miniprep DNA or to use for any other planned experiments. You can also grow the plasmid in the same way from tubes that you have frozen down for storage.

  15. How do I prevent contamination of my Dictyostelium culture?
    Strains on a bacterial plate need to be handled in a sterile hood, or near a Bunsen burner with a sterile loop and in as sterile a condition as is possible. Cells in HL5 should be handled in a sterile hood only.

  16. At what temperature do dicty cells grow?
    Dictyostelium cells grow well at room temperature, 20°C - 22°C is ideal. For slower growth they may be placed at 12°C. Warmer than 25°C or colder than 12°C is generally not recommended.

  17. What do I do with a strain received growing on an agar plate on a bacterial lawn?
    • To allow the strain to continue to grow, or if immediate attendance is not possible, place the strain in a humid enclosure; otherwise the plate will dry out. This can be a plastic box with a loose lid, lined with humid paper-towels (change frequently, beware of mold contaminations!).
    • Grow the bacterial food strain, either from the shipped strain plate or from your separate bacterial strain order.
    • Spread 250uL of bacteria onto an LPB, a GYP, or an SM plate-allowing allow the plate to dry in the hood (do not overdry!). Note that SM plates are by far the richest in nutritient, and LBP are the least rich. In the DSC we observe that many strains grow better on less rich plates
    • Use a sterile loop to streak the strain from the old plate to the new. You may also spot the strain into the center of your bacterial plate. Incubate this plate in a Dicty enclosure at room temperature and use this plate to proceed with your experiments and to plate for storage (see question# 16).

  18. How do I make a bacterially grown strain axenic?
    • If your strain is able to sporulate and you have a stereo microscope, you can pick a couple of spores with a sterile micro pipette tip without touching the bottom of the plate and transfer to a small (5 cm) disch with HL5. Work as clean/sterile as possible and lightly sworl the plate. Incubate at room temperature (22oC). The spores should hatch into amoeba within a couple of hours. Add selective drug to the medium after 7 - 15 hours and expand the axenic culture as necessary. This method is also used to clean up a contaminated strain, see below.
    • If your mutant cells are not able to make spores you need to make vegetative cells axenic by following these instructions on our techniques page. You may exchange the SM plate and use GYP instead, and we also recommend E.coli B/r as the food source.

  19. What kind of bacteria are used as food source for Dictyostelium?
    By default we ship LPB or GYP plates (indicated on the plate) with E.coli B/r as a food source. Occasionally we use the K. aerogenes food strain, which is then indicated on the plate.

  20. How do I store a strain received growing on an agar plate on a bacterial lawn?
    • From a plate with good growth use a loop to scrape cells from the feeding front and place into 900uL of fresh bacteria. Mix well. Spread this evenly onto 3 plates (300uL per plate) using a sterile glass spreader and allow to dry under the hood (do not overdry!).
    • Place the plates back into the Dicty enclosure and harvest when the plates are clearing (i.e. the dicty have consumed all of the bacteria; plates should appear opaque and have a 'forest' smell).
    • To harvest, use a sterile spreader and wash the cells off the plates with 1X KK2 buffer, about 10mL per plate, 30mL for 3 plates. Spin at 500g for 5 min in a tabletop centrifuge. This will leave the bacteria in the supernatant but the much larger Dictyostelium cells spin down.
    • Decant the supernatant and resuspend the pellet (beige-yellowish color) in 30mL 1X KK2; repeat this wash 3 more times to remove as many bacteria as possible.
    • Resuspend the final pellet of Dicty cells in 4.5mL of cold HL5 and vortex. Place on ice.
    • Add 0.55mL DMSO and mix by swirling; do not vortex once DMSO has been added as the cells will be fragile at this stage, place on ice again.
    • Add 1mL of cell suspension per labeled freezing vial; should make about 4 tubes.
    • Place vials on ice for 5-10 min. Freeze slowly! Incubate cells at -20°C for 1-2 h and then transfer to -80°C for 12-24 h.
    • Transfer vials to liquid nitrogen for long-term storage. If liquid nitrogen is unavailable, storage in a -80°C freezer is an acceptable alternative. Also, do not add drug to the HL5 for storage as the cells are fragile and this adds unnecessary stress.

  21. What do I do with a strain received growing in liquid HL5 medium?
    • As soon as you receive the strain in liquid medium, place the whole amount into a Petri dish, or split into two dishes adding some fresh medium. In a 10cm petri dish, typically 10mL medium are used. Alternatively, you may spin a small amount down, mix with bacteria (as described in question #16) , and plate on an LPB or SM plate for bacterial growth.
    • Leave the HL5 plate overnight in a dicty enclosure: a plastic box with a loose lid and a small beaker containing water so as to keep the environment humid. This gives the cells time to settle and recover from shipping.
    • Proceed to storing the strain (see below, question #18). When using cells for experiments, change the medium every other day remembering to add drug as appropriate to maintain the selection.

  22. How do I store a strain received growing in liquid HL5 medium?
    • When the plate looks about confluent (approximate density of about 2-4 x 106 ml-1), split the cells into additional or larger plates and grow them up, changing the medium every other day. Do not overgrow-if medium turns yellow the cells will die!
    • Harvest 1-2 x 108 cells (30mL at about 5 x 106 mL) cells, spin at 500g for 4 min in a tabletop centrifuge. Chill cell pellet on ice for 5 min.
    • Add 10mL of cold HL5 medium and gently vortex to resuspend the cells. Then add 0.55mL of DMSO to a final concentration of 10%. Resuspend the cells gently - do not vortex once DMSO has been added as the cells will be fragile. Do not add drug to the HL5 when storing as it will be too stressful for the cells.
    • Transfer to pre-cooled cryovials and place on ice for 5-10 min. Freeze slowly: incubate cells at -20°C for 1-2 h and then transfer to -80°C for 12-24 h.
    • If liquid nitrogen is unavailable, storage in a -80°C freezer is an acceptable alternative.
    • To thaw, place vial in a ziploc bag in a water bath set at about 30°C. Before it thaws completely, remove from the water bath and transfer to 10mL of HL5 in a Petri dish (do not add drug immediately for the cells to recover from storage). If thawing one tube only, you may hold the tube and swirl in the water bath, removing the tube with a small amount of ice remaining followed by transfer into medium.
    • Change the medium soon after the cells adhere to remove the DMSO. If mutant cells do not adhere, spin down briefly at 500g and resuspend in fresh medium. If applicable, add selection drugs on the next day.

  23. Is trypsin or similar necessary to detach cells from the bottom of a petri dish?
    No trypsin or similar is needed to detach Dicty cells. Pipette gently up and down and the cells will dislodge in the stream. Move your pipette tip over the whole surface of the plate and finally pipette cells into a sterile tube.

  24. How do I 'clean up' a contaminated strain?
    If a strain forms fruiting bodies it can ususally be separated from any contaminant. In all steps work as STERILE and clean as possible.
    • Grow cells and let them fruit on an LBP plate (see question #17).
    • Looking through a steroscope, pick a spore head with a sterile micro-pipette tip (or similar) without touching the bottom of the plate.
    • Touch the pipette tip with the spore head onto a fresh bacterial plate. The Dictyostelium strain should now grow contamination free.
    • Alternatively, you can pick the spore head into a small dish with HL5 (a 2.5 or 5 cm dish) containing HL5. Gently swirl the plate to disperse. Be careful to work as sterile as possible. Ameobae should hatch within a a couple of hours and growth should be free of the contaminant. Add any selective drug after 7-15 hours).



Home| Contact dictyBase| Contact Dicty Stock Center Curators| SOPs| Site Map  Supported by NIH (NIGMS and NHGRI)