 Vaccine compositions |
| OF THE INVENTION Target cells are inactivated by treatment with psoralens and irradiation with LWUV... |
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| Cyanobenzyl cyclopropane carboxylate pesticides |
| We claim: 1. A method of combating insect or acarid pests at a locus which comprises applying to ... |
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| Aqueous flowable concentrates of particulate water-insoluble pesticides |
| What is claimed is: 1. A flowable, viscous, aqueous pesticidal concentrate which is compatible with ... |
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| Perfluoralkylcyanocyclopropenes |
| The embodiments of the invention in which an exclusive property or privilege is claimed are defined ... |
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| Insecticidal esters |
| We claim: 1. The (+), (-), and (.+-.) forms of the compounds of the general formula I ##STR12## ... |
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| Insecticidal esters |
| We claim: 1. The (+), (-) and (.+-.) forms of the compounds of the general formula I ##STR10## ... |
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| Tertiary aromatic amine accelerators in acrylic resin |
| OF INVENTION The tertiary aromatic amines employed in the present invention may be used ... |
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Method for cloning and producing the Msel restriction endonuclease
| Details |
Inventors: Vaisvila, Romualdas; Morgan, Richard D.; Kucera, Rebecca B.; Claus, Toby E.; Raleigh, Elisabeth A.;
Assignee: New England Biolabs, Inc. (Beverly, MA)
Primary Examiner: Guzo; David
Assistant Examiner:
Attorney, Agent or Firm: Strimpel; Harriet M., Williams; Gregory D.
A method for cloning restriction-modification system is provided whereby the target modification methylase is produced and confers full protection during all growth phases in which the cognate restriction enzyme is present. The method is employed in the cloning of the MseI restriction-modification system. |
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DETAILED DESCRIPTION OF THE INVENTION In one embodiment, the present invention relates to a method of producing a target restriction endonuclease by first providing a vector expressing a modification methyltransferase gene protecting DNA from restriction enzyme cleavage, in such a form that complete protection of the host DNA is observed preferably at all growth phases in which the cognate restriction endonuclease is present without leading to toxicity (a fully-protecting methyltransferase vector), followed by providing a vector expressing the desired restriction endonuclease gene.
The present invention is not limited by the identity of the modification methyltransferase gene or restriction enzyme, except that the modification methyltransferase must protect against cleavage by the said restriction enzyme.
In a preferred embodiment, the fully-protecting methyltransferase vector may be obtained by identifying regulatory elements capable of driving methyltransferase expression to provide full protection during a phase of growth that is especially sensitive to methyltransferase expression pattern.
In accordance with the present invention, this may be done by the following steps: (1) obtaining a methyltransferase gene in a vector by methods known in the art; (2) placing a regulatory element such as a promoter in a suitable location with respect to the gene; (3) transformation into the desired host cell; (4) reisolation of vector from the pooled transformants during the time that they are in the logarithmic phase of growth; (5) selection by digestion with the endonuclease; and (6) retransformation of the surviving undigested and thus protected vector population into a fresh host.
It will be understood by those skilled in the art that step (4) of this procedure may be performed with pooled vector isolated from logarithmic phase or from various other phases of growth, for example from stationary phase, from a resting state achieved by starvation for carbon or nitrogen or other essential nutrient, or from cells in a special physiological state, such as a state of DNA damage, or in the presence of physiological insults such as acidic media or toxic compounds, as may be appropriate
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Molecular Biology 
