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- Wagner, Samuel, et al.
(författare)
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Tuning Escherichia coli for membrane protein overexpression
- 2008
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 105:38, s. 14371-17376
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Tidskriftsartikel (refereegranskat)abstract
- A simple generic method for optimizing membrane protein overexpression in Escherichia coli is still lacking. We have studied the physiological response of the widely used “Walker strains” C41(DE3) and C43(DE3), which are derived from BL21(DE3), to membrane protein overexpression. For unknown reasons, overexpression of many membrane proteins in these strains is hardly toxic, often resulting in high overexpression yields. By using a combination of physiological, proteomic, and genetic techniques we have shown that mutations in the lacUV5 promoter governing expression of T7 RNA polymerase are key to the improved membrane protein overexpression characteristics of the Walker strains. Based on this observation, we have engineered a derivative strain of E. coli BL21(DE3), termed Lemo21(DE3), in which the activity of the T7 RNA polymerase can be precisely controlled by its natural inhibitor T7 lysozyme (T7Lys). Lemo21(DE3) is tunable for membrane protein overexpression and conveniently allows optimizing overexpression of any given membrane protein by using only a single strain rather than a multitude of different strains. The generality and simplicity of our approach make it ideal for high-throughput applications.
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- Welinder, Annika, et al.
(författare)
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Diagnostic conclusions from the EASI-derived 12-lead electrocardiogram as compared with the standard 12-lead electrocardiogram in children.
- 2006
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Ingår i: American Heart Journal. - : Elsevier BV. - 1097-6744 .- 0002-8703. ; 151:5, s. 1059-1064
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Tidskriftsartikel (refereegranskat)abstract
- Background Fewer electrodes on more easily located places would facilitate electrocardiogram (ECG) recording. To investigate the possibility of simplifying ECG recording in children, we compared the diagnostic conclusions when interpreting standard versus EASI-derived 12-lead ECGs. Our hypothesis was that the variation of the interpretation of standard versus EASI-derived 12-lead ECGs was not greater than the intrareader variation of the interpretation of standard ECGs. Methods The study included 221 children. The 2 lead systems were recorded simultaneously. Two experienced pediatric cardiologists interpreted the ECGs. First, the reader interpreted a set of 221 ECGs with randomly allocated standard and EASI-derived 12-lead ECGs. Next, the reader interpreted the complementary ECG set without having access to the first set. Finally, the reader reinterpreted the standard ECGs from 98 children. Results The variation of the interpretation of standard versus EASI-derived 12-lead ECGs was only slightly larger than the intrareader variation of the interpretation of standard ECGs. Conclusions For most of the electrocardiographic diagnoses, the conclusions from EASI-derived 12-lead ECGs were similar to those from standard ECGs. These findings support the suggestion that the EASI lead system is a potential alternative to the standard ECG in children.
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