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nitrosoguanidine-induced mutant of stock 51, 1968

Temperature: 25.0°C

Protocol: ATCCNO: 30300 SPEC: This strain is shipped as a growing test tube culture. Upon arrival, remove test tube from sealed plastic envelope, remove plastic seal from cap, and loosen the cap one half turn. Add 1.0 ml of ATCC medium 802 bacterized with Enterobacter aerogenes ATCC 13048 twice weekly. When the tube is filled to within one inch of the top, decant leaving 5.0 ml in the original tube. Subcultures are established by transferring 0.5 ml of a growing culture to 5.0 ml of bacterized ATCC medium 802 in a 20 x 120 mm test tube.

Protocol: ATCCNO: 30300 SPEC: This strain is shipped as a growing test tube culture. Upon arrival, remove test tube from sealed plastic envelope, remove plastic seal from cap, and loosen the cap one half turn. Add 1.0 ml of ATCC medium 802 bacterized with Enterobacter aerogenes ATCC 13048 twice weekly. When the tube is filled to within one inch of the top, decant leaving 5.0 ml in the original tube. Subcultures are established by transferring 0.5 ml of a growing culture to 5.0 ml of bacterized ATCC medium 802 in a 20 x 120 mm test tube.

Cryoprotective Solution

DMSO ?????????????????????????????????????????????????????????????????????????????????? 1.5 ml

Fresh growth medium w/o bacteria???????????????????????????????? 7.5 ml

MgCl₂ (0.5 mM)??????????????????????????????????????????????????????????????????? 0.5 ml

CaCl₂ (0.5 mM)??????????????????????????????????????????????????????????????????? 0.5 ml

1.?? Mix the components in the order listed.? Before adding the MgCl₂ and the CaCl₂ allow the solution to return to room temperature.? When the medium is added to the DMSO the solution will warm up due to chemical heat.

2. ? Harvest cells from a culture that is at or near peak density by filtration and centrifugation at 200 x g for 1 min.

3. Adjust the concentration of cells to 2 x 10⁵/ml in fresh medium.

4.? Mix the cell preparation and the cryoprotective solution in equal portions.

5.? Dispense in 0.5 ml aliquots into 1.0 - 2.0 ml sterile plastic screw-capped cryules (special plastic vials for cryopreservation).

6.? Place vials in a controlled rate freezing unit. From room temperature cool at -1°C/min to -40°C. If freezing unit can compensate for the heat of fusion, maintain rate at -1 C/min through heat of fusion. At -40°C plunge ampules into liquid nitrogen.

7.? Ampules are stored in either the vapor or liquid phase of a nitrogen refrigerator.

8. To establish a culture from the frozen state add 1.0 ml ATCC medium 802 to the frozen ampule and place it in a 35°C water bath.? Immerse the vial? to a level just above the surface of the frozen material. Do not agitate the vial.

9.   Immediately after thawing, do not leave in water bath, aseptically remove the contents of the ampule and inoculate onto the surface of an ATCC medium 919 (non-nutrient agar) plate containing an overlay of 15.0 ml of bacterized ATCC medium 802.

10. Incubate at 25°C.

11. Once the culture is established, transfer 0.5 ml to 5.0 ml of bacterized ATCC medium 802.

12. Follow the protocol for maintenance of culture.

ATCC <<--JR Preer<<--T.M. Sonneborn <<--- C. Kung