9 research outputs found
ExCyto PCR Amplification
ExCyto PCR cells provide a novel and cost effective means to amplify DNA transformed into competent bacterial cells. ExCyto PCR uses host E. coli with a chromosomally integrated gene encoding a thermostable DNA polymerase to accomplish robust, hot-start PCR amplification of cloned sequences without addition of exogenous enzyme.Because the thermostable DNA polymerase is stably integrated into the bacterial chromosome, ExCyto cells can be transformed with a single plasmid or complex library, and then the expressed thermostable DNA polymerase can be used for PCR amplification. We demonstrate that ExCyto cells can be used to amplify DNA from different templates, plasmids with different copy numbers, and master mixes left on ice for up to two hours. Further, PCR amplification with ExCyto cells is comparable to amplification using commercial DNA polymerases. The ability to transform a bacterial strain and use the endogenously expressed protein for PCR has not previously been demonstrated.ExCyto PCR reduces pipetting and greatly increases throughput for screening EST, genomic, BAC, cDNA, or SNP libraries. This technique is also more economical than traditional PCR and thus broadly useful to scientists who utilize analysis of cloned DNAs in their research
Statins in the Treatment of Chronic Heart Failure: A Systematic Review
BACKGROUND: The efficacy of statin therapy in patients with established chronic heart failure (CHF) is a subject of much debate. METHODS AND FINDINGS: We conducted three systematic literature searches to assess the evidence supporting the prescription of statins in CHF. First, we investigated the participation of CHF patients in randomized placebo-controlled clinical trials designed to evaluate the efficacy of statins in reducing major cardiovascular events and mortality. Second, we assessed the association between serum cholesterol and outcome in CHF. Finally, we evaluated the ability of statin treatment to modify surrogate endpoint parameters in CHF. Using validated search strategies, we systematically searched PubMed for our three queries. In addition, we searched the reference lists from eligible studies, used the “see related articles” feature for key publications in PubMed, consulted the Cochrane Library, and searched the ISI Web of Knowledge for papers citing key publications. Search 1 resulted in the retrieval of 47 placebo-controlled clinical statin trials involving more than 100,000 patients. CHF patients had, however, been systematically excluded from these trials. Search 2 resulted in the retrieval of eight studies assessing the relationship between cholesterol levels and outcome in CHF patients. Lower serum cholesterol was consistently associated with increased mortality. Search 3 resulted in the retrieval of 18 studies on the efficacy of statin treatment in CHF. On the whole, these studies reported favorable outcomes for almost all surrogate endpoints. CONCLUSIONS: Since CHF patients have been systematically excluded from randomized, controlled clinical cholesterol-lowering trials, the effect of statin therapy in these patients remains to be established. Currently, two large, randomized, placebo-controlled statin trials are under way to evaluate the efficacy of statin treatment in terms of reducing clinical endpoints in CHF patients in particular
Changes in absolute gravity 2000–2015, South Island, New Zealand
<p>We quantify changes in gravity that have occurred over the past 15 years at 14 points between latitudes 42.5°S and 44°S in the South Island of New Zealand. Ten of the points form two transects across the Southern Alps and four lie in the epicentral region of the 2010 Canterbury earthquakes. At each location gravity was measured using an absolute gravimeter (FG5–111) with a nominal accuracy of 1 µGal. Observed changes in gravity varied from −53 to +43 µGal in the presence of surface elevation changes in the range −11 cm to +20 cm. Despite the difficulty in quantifying gravitational contributions from surface and subsurface water, uplift in both the Southern Alps and the Christchurch region is consistent with a Bouguer surface gradient of approximately 1.97 µGal cm<sup>–1</sup>, appropriate for the mean density of crustal rocks.</p
Gravimetric Methods – Absolute and Relative Gravity Meter: Instruments Concepts and Implementation
Dilution series of ExCyto PCR cells.
<p>Eight different clones from a cDNA library transformed into ExCyto cells were grown overnight, and a serial dilution was used for amplification (undiluted, 100-, and 1000-fold dilutions). In (A), bacteria were diluted, reducing both the target DNA and the tsDNA polymerase. In (B), to compensate for the serial dilution of the tsDNA polymerase, 2 ul of ExCyto cells (OD 1.1) without plasmids was added. In (C), to compensate for the serial dilution of plasmid, 2 ul of bacteria with the same plasmid, but without the tsDNA polymerase was added. A 10-fold dilution is not shown, but gives similar amplification to that seen with undiluted cells. One kb molecular weight markers are shown in the last lane.</p
ExCyto PCR amplification.
<p>A cDNA library was transformed into ExCyto cells. Twenty-four different cDNAs were amplified without addition of exogenous polymerase using (A) single colonies, (B) 2 µl of frozen glycerol stocks, or (C) 2 µl of overnight cultures. One kb molecular weight markers are shown in the last lane.</p
ExCyto PCR of chromosomal integrants.
<p>Two µl of overnight cultures from chromosomal integrants were used for PCR with primers flanking the melAmelB bicistron integration site. Integrants show a band at 4.5 kb. Wild type (WT, last lane) has a band at 2 kb. One kb molecular weight markers are shown in the first lane.</p