Selection and characterization of RNA aptamers that detect a quaternary structure for ribosomal protein S7

Here we report on the selection and characterization of RNA aptamers that recognize E. coli ribosomal protein S7. Ribosomal protein S7 plays two important roles in ribosome biogenesis: (1) as an assembly initiator, S7 nucleates the folding of the 3\u27 major domain of 16S rRNA, and (2) it binds to the str operon and represses the translation of S12, S7, and EF-G. The primary and secondary structures of the S7 binding sites of rRNA and mRNA share limited sequence and structural homology and the required elements for high affinity binding have not been entirely elucidated. We have selected RNA aptamers that share very little primary sequence homology to either the S7 binding site of 16S rRNA or to the intercistronic region of str mRNA. Many of the aptamers are expected to fold into three-helix junctions, a structure particularly reminiscent of the mRNA. Interestingly, the aptamers exhibit cooperative binding with Hill coefficients of ~3 indicating that they are detecting a quaternary structure of S7. We have found that the S7 aptamers use the same amino acids and structural elements to bind S7 as the rRNA and mRNA indicating that the same binding site is used for all three RNAs. With gel filtration, we were only able to isolate the aptamer/S7 complex at a 1:1 stoichiometry, indicating that the proposed quaternary structure of S7 is weak. However, deletion of the β-ribbon nearly eliminates cooperative aptamer binding suggesting that this structural element may be involved in protein-protein interaction. Furthermore, pre-treatment of native S7 with the N-terminal extension also results in a significant reduction in cooperative aptamer binding. The results presented here suggest that S7 itself may undergo conformational rearrangement subsequent to 16S rRNA binding, and may help explain the strong temperature-dependent rearrangements at the binding site of S7 within the 16S rRNA. Furthermore, we propose that the weak, multimeric interaction of S7 may have a role in the retroregulation of S12. S7 may bind to the mRNA in a pre-multimerized form or multimerize subsequent to binding, resulting in ribosome stalling due to the multimeric obstacle. If the S7/S7 interaction is weak however, then it may be easily disrupted by repeated ribosome bombardment, causing eventual decay of the multimer and relieving some of the translational repression. Translational repression of the genes encoding S7 and EF-G would remain constant over time however, because the monomeric S7 bound more tightly to the intercistronic region would continue to prevent translational coupling with the upstream gene encoding S12

Choral Ensembles Spring Concert

This Kennesaw State University School of Music performance features Chamber Singers, Men\u27s Ensemble, and University Chorale directed by Dr. Leslie Blackwell, Director of Choral Activities and Professor of Music and Music Education.https://digitalcommons.kennesaw.edu/musicprograms/2054/thumbnail.jp

The epidemiology and outcomes of invasive \u3ci\u3eCandida\u3c/i\u3e infections among organ transplant recipients in the United States: results of the Transplant-Associated Infection Surveillance Network (TRANSNET)

Background: Invasive candidiasis (IC) is a common cause of mortality in solid organ transplant recipients (OTRs), but knowledge of epidemiology in this population is limited. Method: The present analysis describes data from 15 US centers that prospectively identified IC from nearly 17 000 OTRs. Analyses were undertaken to determine predictors of infection and mortality. Results: A total of 639 cases of IC were identified. The most common species was Candida albicans (46.3%), followed by Candida glabrata (24.4%) and Candida parapsilosis (8.1%). In 68 cases \u3e1 species was identified. The most common infection site was bloodstream (44%), followed by intra-abdominal (14%). The most frequently affected allograft groups were liver (41.1%) and kidney (35.3%). All-cause mortality at 90 days was 26.5% for all species and was highest for Candida tropicalis (44%) and C. parapsilosis (35.2%). Non-white race and female gender were more commonly associated with non-albicans species. A high rate of breakthrough IC was seen in patients receiving antifungal prophylaxis (39%). Factors associated with mortality include organ dysfunction, lung transplant, and treatment with a polyene antifungal. The only modifiable factor identified was choice of antifungal drug class based upon infecting Candida species. Conclusion: These data highlight the common and distinct features of IC in OTRs

Chamber Singers, Men\u27s Ensemble and University Chorale, Requiem for the Living

KSU School of Music presents Chamber Singers, Men\u27s Ensemble and University Chorale directed by Dr. Leslie Blackwell, Director of Choral Activities and Professor of Music and Music Education.https://digitalcommons.kennesaw.edu/musicprograms/2033/thumbnail.jp

Manual / Issue 12 / On Further Review

Manual, a journal about art and its making. On Further Review. This issue uncovers narratives once central to objects’ histories but that now have been systematically obscured, inadvertently overlooked, or otherwise lost. Softcover, 96 pages. Published 2019 by the RISD Museum.(On Further Review) contributors include Anita N. Bateman, Laurie Anne Brewer, Becci Davis, Jamie Gabbarelli, Bethany Johns, Elon Cook Lee, Kevin McBride, Walker Mettling, Jessica Rosner, Suzanne Scanlan, Nell Painter, Allison Pappas, Pamela A. Parmal, Shiyanthi Thavapalan, and Nick White.https://digitalcommons.risd.edu/risdmuseum_journals/1038/thumbnail.jp

The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and Parameters

We present the temperature and polarization angular power spectra measured by the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time data collected during 2013-14 using two detector arrays at 149 GHz, from 548 deg$^2$ of sky on the celestial equator. We use these spectra, and the spectra measured with the MBAC camera on ACT from 2008-10, in combination with Planck and WMAP data to estimate cosmological parameters from the temperature, polarization, and temperature-polarization cross-correlations. We find the new ACTPol data to be consistent with the LCDM model. The ACTPol temperature-polarization cross-spectrum now provides stronger constraints on multiple parameters than the ACTPol temperature spectrum, including the baryon density, the acoustic peak angular scale, and the derived Hubble constant. Adding the new data to planck temperature data tightens the limits on damping tail parameters, for example reducing the joint uncertainty on the number of neutrino species and the primordial helium fraction by 20%.Comment: 23 pages, 25 figure

Estimating Incidence Curves of Several Infections Using Symptom Surveillance Data

We introduce a method for estimating incidence curves of several co-circulating infectious pathogens, where each infection has its own probabilities of particular symptom profiles. Our deconvolution method utilizes weekly surveillance data on symptoms from a defined population as well as additional data on symptoms from a sample of virologically confirmed infectious episodes. We illustrate this method by numerical simulations and by using data from a survey conducted on the University of Michigan campus. Last, we describe the data needs to make such estimates accurate

The atacama cosmology telescope: lensing of CMB temperature and polarization derived from cosmic infrared background cross-correlation

We present a measurement of the gravitational lensing of the Cosmic Microwave Background (CMB) temperature and polarization fields obtained by cross-correlating the reconstructed convergence signal from the first season of Atacama Cosmology Telescope Polarimeter data at 146 GHz with Cosmic Infrared Background (CIB) fluctuations measured using the Planck satellite. Using an effective overlap area of 92.7 square degrees, we detect gravitational lensing of the CMB polarization by large-scale structure at a statistical significance of $4.5\sigma$. Combining both CMB temperature and polarization data gives a lensing detection at $9.1\sigma$ significance. A B-mode polarization lensing signal is present with a significance of $3.2\sigma$. We also present the first measurement of CMB lensing–CIB correlation at small scales corresponding to $l\gt 2000$. Null tests and systematic checks show that our results are not significantly biased by astrophysical or instrumental systematic effects, including Galactic dust. Fitting our measurements to the best-fit lensing-CIB cross-power spectrum measured in Planck data, scaled by an amplitude A, gives $A={1.02}_{-0.08}^{+0.12}$(stat.) ± 0.06(syst.), consistent with the Planck results

The Atacama Cosmology Telescope: CMB Polarization at 200<ℓ<9000200<\ell<9000

We report on measurements of the cosmic microwave background (CMB) and celestial polarization at 146 GHz made with the Atacama Cosmology Telescope Polarimeter (ACTPol) in its first three months of observing. Four regions of sky covering a total of 270 square degrees were mapped with an angular resolution of $1.3'$. The map noise levels in the four regions are between 11 and 17 $\mu$K-arcmin. We present TT, TE, EE, TB, EB, and BB power spectra from three of these regions. The observed E-mode polarization power spectrum, displaying six acoustic peaks in the range $200<\ell<3000$, is an excellent fit to the prediction of the best-fit cosmological models from WMAP9+ACT and Planck data. The polarization power spectrum, which mainly reflects primordial plasma velocity perturbations, provides an independent determination of cosmological parameters consistent with those based on the temperature power spectrum, which results mostly from primordial density perturbations. We find that without masking any point sources in the EE data at $\ell<9000$, the Poisson tail of the EE power spectrum due to polarized point sources has an amplitude less than $2.4$ $\mu$K$^2$ at $\ell = 3000$ at 95\% confidence. Finally, we report that the Crab Nebula, an important polarization calibration source at microwave frequencies, has 8.7\% polarization with an angle of $150.7^\circ \pm 0.6^\circ$ when smoothed with a $5'$ Gaussian beam.Comment: 16 pages, 15 figures, 5 table