24 research outputs found
Cluster J Mycobacteriophages: Intron Splicing in Capsid and Tail Genes
Bacteriophages isolated on Mycobacterium smegmatis mc2155 represent many distinct genomes sharing little or no DNA sequence similarity. The genomes are architecturally mosaic and are replete with genes of unknown function. A new group of genomes sharing substantial nucleotide sequences constitute Cluster J. The six mycobacteriophages forming Cluster J are morphologically members of the Siphoviridae, but have unusually long genomes ranging from 106.3 to 117 kbp. Reconstruction of the capsid by cryo-electron microscopy of mycobacteriophage BAKA reveals an icosahedral structure with a triangulation number of 13. All six phages are temperate and homoimmune, and prophage establishment involves integration into a tRNA-Leu gene not previously identified as a mycobacterial attB site for phage integration. The Cluster J genomes provide two examples of intron splicing within the virion structural genes, one in a major capsid subunit gene, and one in a tail gene. These genomes also contain numerous freestanding HNH homing endonuclease, and comparative analysis reveals how these could contribute to genome mosaicism. The unusual Cluster J genomes provide new insights into phage genome architecture, gene function, capsid structure, gene mobility, intron splicing, and evolution
Neutron Decay Correlations in the Nab Experiment
The Nab experiment will measure the correlation a between the momenta of the beta particle and antineutrino in neutron decay as well as the Fierz term b which distorts the beta spectrum
US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report
This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in
Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference
The Lyman Continuum Escape Fraction of Star-forming Galaxies at from UVCANDELS
The UltraViolet Imaging of the Cosmic Assembly Near-infrared Deep
Extragalactic Legacy Survey Fields (UVCANDELS) survey is a Hubble Space
Telescope (HST) Cycle-26 Treasury Program, allocated in total 164 orbits of
primary Wide-Field Camera 3 Ultraviolet and Visible light F275W imaging with
coordinated parallel Advanced Camera for Surveys F435W imaging, on four of the
five premier extragalactic survey fields: GOODS-N, GOODS-S, EGS, and COSMOS. We
introduce this survey by presenting a thorough search for galaxies at
that leak significant Lyman continuum (LyC) radiation, as well as
a stringent constraint on the LyC escape fraction () from stacking
the UV images of a population of star-forming galaxies with secure redshifts.
Our extensive search for LyC emission and stacking analysis benefit from the
catalogs of high-quality spectroscopic redshifts compiled from archival
ground-based data and HST slitless spectroscopy, carefully vetted by dedicated
visual inspection efforts. We report a sample of five galaxies as individual
LyC leaker candidates, showing estimated
using detailed Monte Carlo analysis of intergalactic medium attenuation. We
develop a robust stacking method to apply to five samples of in total 85
non-detection galaxies in the redshift range of . Most stacks
give tight 2- upper limits below . A stack
for a subset of 32 emission-line galaxies shows tentative LyC leakage detected
at 2.9-, indicating at ,
supporting the key role of such galaxies in contributing to the cosmic
reionization and maintaining the UV ionization background. These new F275W and
F435W imaging mosaics from UVCANDELS have been made publicly available on the
Barbara A. Mikulski Archive for Space Telescopes.Comment: 33 pages, 21 figures, and 5 tables. Resubmitted after addressing the
referee repor
Cluster J mycobacteriophages: intron splicing in capsid and tail genes
Bacteriophages isolated on Mycobacterium smegmatis mc2155 represent many distinct genomes sharing little or no DNA sequence similarity. The genomes are architecturally mosaic and are replete with genes of unknown function. A new group of genomes sharing substantial nucleotide sequences constitute Cluster J. The six mycobacteriophages forming Cluster J are morphologically members of the Siphoviridae, but have unusually long genomes ranging from 106.3 to 117 kbp. Reconstruction of the capsid by cryo-electron microscopy of mycobacteriophage BAKA reveals an icosahedral structure with a triangulation number of 13. All six phages are temperate and homoimmune, and prophage establishment involves integration into a tRNA-Leu gene not previously identified as a mycobacterial attB site for phage integration. The Cluster J genomes provide two examples of intron splicing within the virion structural genes, one in a major capsid subunit gene, and one in a tail gene. These genomes also contain numerous free-standing HNH homing endonuclease, and comparative analysis reveals how these could contribute to genome mosaicism. The unusual Cluster J genomes provide new insights into phage genome architecture, gene function, capsid structure, gene mobility, intron splicing, and evolution
Genome maps of Mycobacteriophage BAKA.
<p>The annotated map of BAKA is represented as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069273#pone-0069273-g003" target="_blank">Figure 3</a>.</p
HNH endonuclease phamilies in Cluster J phages.
<p><b>A</b>, <b>B</b>. Pham circles for phams 3687 (A) and 6944 (B). Phage names are organized by cluster/subcluster sequentially in a clockwise direction around the edge of the circle. Phages containing a gene within each pham are connected by an arc in blue (BLASTP) or red (ClustalW). Cirlces were drawn using Phamerator and thresholds of 32% identity and an E value of 10<sup>-50</sup> for ClustalW and BlastP respectively. <b>C</b>, <b>D</b>. Phylogenetic trees of pham 3687 genes (C) and pham 6944 genes (D). Trees were generated using ClustalW multisequence alignments and neighbor-joining. Trees were drawn using NJPlot. Phages are color coded to designate cluster assignment, as shown in the key.</p
Dotplot of Cluster J and two Subcluster F1 phages.
<p>Whole genome nucleotide sequences of the Cluster J phages and phages Wee and DeadP from Cluster F1 were compared to themselves and to each other using the program Gepard [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069273#B48" target="_blank">48</a>]. Dotted lines are used to indicate the correspondence of the common segment in Wee and DeadP with the Thibault genome.</p
Genome maps of Mycobacteriophage Optimus.
<p>The annotated map of Optimus is represented as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0069273#pone-0069273-g003" target="_blank">Figure 3</a>.</p