Methods for lyophilizing competent cells
First Claim
1. A method of preparing lyophilized gram negative prokaryotic competent cells, comprising first rendering gram negative prokaryotic cells competent, then lyophilizing said competent cells, wherein said lyophilized competent cells exhibit a transformation efficiency of between about 1×
- 105 and 1×
109 transformants per microgram of DNA upon rehydration.
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Abstract
This invention relates to a method for producing cells which are competent for transformation and which may be stably stored for extended periods of time at various temperatures. The method involves growing cells in a growth conducive medium, rendering said cells competent, and lyophilizing said competent cells. The invention further relates to competent cells produced by such a method, to methods of transforming said cells with a DNA molecule, and to a method of producing a desired protein or polypeptide from said transformed cells.
89 Citations
37 Claims
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1. A method of preparing lyophilized gram negative prokaryotic competent cells, comprising first rendering gram negative prokaryotic cells competent, then lyophilizing said competent cells, wherein said lyophilized competent cells exhibit a transformation efficiency of between about 1×
- 105 and 1×
109 transformants per microgram of DNA upon rehydration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- 105 and 1×
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11. A method of preparing lyophilized gram negative prokaryotic competent cells, comprising first rendering gram negative prokaryotic cells competent, then lyophilizing said competent cells, wherein said lyophilized competent cells upon rehydration exhibit a transformation efficiency after storage for 30 days to 120 days at −
- 20°
C. that is about 40% to 100% of the transformation efficiency that said cells exhibit upon rehydration immediately after lyophilization. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
- 20°
- 19. A method of preparing lyophilized competent cells, comprising (a) growing said cells in a growth conducive medium, (b) rendering the cells competent, and then (c) lyophilizing said competent cells , wherein said competent cells do not appreciably lose transformation efficiency when stored for extended periods of time.
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29. A composition comprising:
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a plurality of competent gram negative bacterial cells; and at least one cryoprotectant; wherein said composition is lyophilized, and wherein said competent gram negative bacterial cells, when rehydrated, exhibit a transformation efficiency of between about 105 to about 109 transformants/μ
g DNA. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37)
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Specification