RNA polymerase II synthesizes antisense RNA in Plasmodium falciparum

The recent identification of antisense RNA in the transcriptomes of many eukaryotes has generated enormous interest. The presence of antisense RNA in Plasmodium falciparum, the causative agent of severe malaria, remains controversial. Elucidation of the mechanism of antisense RNA in P. falciparum synthesis is critical in order to demonstrate the origin and function of these transcripts. Therefore, a systematic analysis of antisense and sense RNA synthesis was performed using direct labeling experiments. Nuclear run on experiments with single-stranded DNA probes demonstrated that antisense RNA is synthesized in the nucleus at several genomic loci. Antisense RNA synthesis is sensitive to the potent RNA polymerase II inhibitor α-amanitin. Antisense and sense transcription was also detected in nuclei isolated from synchronized parasites, suggesting concurrent synthesis. In summary, our experiments directly demonstrate that antisense RNA synthesis is a common transcriptional phenomenon in P. falciparum, and is catalyzed by RNA polymerase II. Copyright © 2005 RNA Society

Non-detection of Helium in the Upper Atmospheres of Three Sub-Neptune Exoplanets

We present a search for helium in the upper atmospheres of three sub-Neptune size planets to investigate the origins of these ubiquitous objects. The detection of helium for a low density planet would be strong evidence for the presence of a primary atmosphere accreted from the protoplanetary nebula because large amounts of helium are not expected in the secondary atmospheres of rocky planets. We used Keck+NIRSPEC to obtain high-resolution transit spectroscopy of the planets GJ1214b, GJ9827d, and HD97658b around the 10,833 Ang He triplet feature. We did not detect helium absorption for any of the planets despite achieving a high level of sensitivity. We used the non-detections to set limits on the planets' thermosphere temperatures and atmospheric loss rates by comparing grids of 1D models to the data. We also performed coupled interior structure and atmospheric loss calculations, which suggest that the bulk atmospheres (winds) of the planets would be at most modestly enhanced (depleted) in helium relative to their primordial composition. Our lack of detections of the helium triplet for GJ1214b and GJ9827d are highly inconsistent with the predictions of models for the present day mass loss on these planets. Higher signal-to-noise data would be needed to detect the helium feature predicted for HD97658b. We identify uncertainties in the EUV fluxes of the host stars and the lack of detailed mass loss models specifically for cool and metal-enhanced atmospheres as the main limitations to the interpretation of our results. Ultimately, our results suggest that the upper atmospheres of sub-Neptune planets are fundamentally different than those of gas giant planets.Comment: AJ in pres

The Association of a classical left bundle Branch Block Contraction Pattern by vendor-independent strain echocardiography and outcome after cardiac resynchronization therapy

Background: The association of a Classical left bundle branch block (LBBB) contraction pattern and better outcome after cardiac resynchronization therapy (CRT) has only been studied using vendor-specific software for echocardiographic speckle-tracked longitudinal strain analysis. The purpose of this study was to assess whether a Classical LBBB contraction pattern on longitudinal strain analysis using vendor-independent software is associated with clinical outcome in CRT recipients with LBBB. Methods: This was a retrospective cohort study including CRT recipients with LBBB, heart failure, and left ventricular (LV) ejection fraction ≤35%. Speckle-tracked echocardiographic longitudinal strain analysis was performed retrospectively on echocardiograms using vendor-independent software. The presence of a Classical LBBB contraction pattern was determined by consensus of two readers. The primary end point was a composite of time to death, heart transplantation or LV assist device implantation. Secondary outcome was ≥15% reduction in LV end-systolic volume. Intra- and inter-reader agreement of the longitudinal strain contraction pattern was assessed by calculating Cohen's κ. Results: Of 283 included patients, 113 (40%) were women, mean age was 66 ± 11 years, and 136 (48%) had ischemic heart disease. A Classical LBBB contraction pattern was present in 196 (69%). The unadjusted hazard ratio for reaching the primary end point was 1.93 (95% confidence interval, 1.36-2.76, p &lt; 0.001) when comparing patients without to patients with a Classical LBBB contraction pattern. Adjusted for ischemic heart disease and QRS duration &lt; 150 milliseconds the hazard ratio was 1.65 (95% confidence interval, 1.12-2.43, p = 0.01). Of the 123 (43%) patients with a follow-up echocardiogram, 64 of 85 (75%) of patients with a Classical LBBB contraction pattern compared to 13 of 38 (34%) without, had ≥15% reduction in LV end-systolic volume (p &lt; 0.001). Cohen's κ were 0.86 (95% confidence interval, 0.71-1.00) and 0.42 (95% confidence interval, 0.30-0.54) for intra- and inter-reader agreement, respectively. Conclusion: Using vendor-independent strain software, a Classical LBBB contraction pattern is associated with better outcome in CRT recipients with LBBB, but inter-reader agreement for the classification of contraction pattern is only moderate.</p

Evidence for a narrow dip structure at 1.9 GeV/c2^2 in 3π+3π−3\pi^+ 3\pi^- diffractive photoproduction

A narrow dip structure has been observed at 1.9 GeV/c$^2$ in a study of diffractive photoproduction of the $~3\pi^+3\pi^-$ final state performed by the Fermilab experiment E687.Comment: The data of Figure 6 can be obtained by downloading the raw data file e687_6pi.txt. v5 (2nov2018): added Fig. 7, the 6 pion energy distribution as requested by a reade