28 research outputs found
DataSheet1_Flour derived porous carbon as anode for highly robust potassium-ion batteries.doc
Potassium-ion batteries (PIBs) have attracted increasing research interest because of the natural abundance and low cost of potassium. Nevertheless, lacking of suitable anode materials that can deliver high reversible capacity and long cycle life highly hinder the further development of PIBs. Here, we report a flour chemistry strategy to establish a porous phosphorus-doped carbon (PPDC) as anode for high-performance PIBs. The as-prepared PPDC with high hierarchically porous structure and rich P-doping not only offers fast transport of K+ and electrons during continuous cycling, but also affords sufficient inner space to relieve volume expansion of active electrode. Therefore, the PPDC displayed high reversible capacity, excellent cyclic stability, outstanding rate performance. These results imply a great potential for applications in the field of high-energy storage devices.</p
Intermolecular Sulfur···Oxygen Interactions: Theoretical and Statistical Investigations
Intermolecular
S···O interactions are very common
and are important in biological systems, but until recently, the presence
of these contacts in protein–ligand systems largely depended
on serendipitous discovery instead of rational design. Here we provide
insight into the phenomenon of intermolecular S···O
contacts by focusing on three sulfur-containing aromatic rings. Quantum
mechanics is employed to characterize the strength and directionality
of the S···O interactions and to determine their energy
dependence on their geometric parameters. Protein Data Bank mining
is performed to systematically determine the occurrence and geometry
of intermolecular S···O interactions, and several representative
examples are discussed. Three typical cases are investigated using
a combined quantum mechanics/molecular mechanics approach to demonstrate
the potential of these interactions in improving binding affinities
and physiochemical properties. Overall, our work elucidates the structures
and energy features of intermolecular S···O interactions
and addresses their use in molecular design
Endogenous retroviruses of non-avian/mammalian vertebrates illuminate diversity and deep history of retroviruses
<div><p>The deep history and early diversification of retroviruses remains elusive, largely because few retroviruses have been characterized in vertebrates other than mammals and birds. Endogenous retroviruses (ERVs) documented past retroviral infections and thus provide ‘molecular fossils’ for studying the deep history of retroviruses. Here we perform a comprehensive phylogenomic analysis of ERVs within the genomes of 92 non-avian/mammalian vertebrates, including 72 fishes, 4 amphibians, and 16 reptiles. We find that ERVs are present in all the genomes of jawed vertebrates, revealing the ubiquitous presence of ERVs in jawed vertebrates. We identify a total of >8,000 ERVs and reconstruct ~450 complete or partial ERV genomes, which dramatically expands the phylogenetic diversity of retroviruses and suggests that the diversity of exogenous retroviruses might be much underestimated in non-avian/mammalian vertebrates. Phylogenetic analyses show that retroviruses cluster into five major groups with different host distributions, providing important insights into the classification and diversification of retroviruses. Moreover, we find retroviruses mainly underwent frequent host switches in non-avian/mammalian vertebrates, with exception of spumavirus-related viruses that codiverged with their ray-finned fish hosts. Interestingly, ray-finned fishes and turtles appear to serve as unappreciated hubs for the transmission of retroviruses. Finally, we find retroviruses underwent many independent water-land transmissions, indicating the water-land interface is not a strict barrier for retrovirus transmission. Our analyses provide unprecedented insights into and valuable resources for studying the diversification, key evolutionary transitions, and macroevolution of retroviruses.</p></div
The distribution of major retroviral clades in vertebrates.
<p>The left panel shows the phylogenetic relationship among major vertebrate groups. The numbers near the vertebrates indicate the numbers of genomes used in this study. The top-right panel shows the phylogenetic relationship among the five major retroviral groups. XRV and ERV stand for exogenous and endogenous retrovirus, respectively. <i>α</i>, <i>β</i>, <i>γ</i>, <i>δ</i>, <i>ε</i>, <i>Lenti-</i>, and <i>Spuma-</i> represent <i>Alpharetrovirus</i>, <i>Betaretrovirus</i>, <i>Gammaretrovirus</i>, <i>Deltaretrovirus</i>, <i>Epsilonretrovirus</i>, <i>Lentivirus</i>, and <i>Spumavirus</i>, respectively. I, II, and III represent class I, II, and III ERVs. The filled circles indicate the presence of ERVs.</p
Retroviral transmission modes at the land-water interface.
<p>The blue boxes indicate aquatic environments. (<b>A</b>) Scenario where retroviruses underwent water-to-land transition simultaneously with the conquest of land by their tetrapod hosts. (<b>B</b>) Scenario where tetrapod retroviruses independently originated by cross-species transmissions from fishes to tetrapods after the origin of tetrapods.</p
Host-virus phylogeny congruence test for retroviruses.
<p>Host-virus phylogeny congruence test for retroviruses.</p
Transmission network of retroviruses among major vertebrate lineages.
<p>The gray lines represent the phylogenetic relationship among major vertebrate groups. The pink lines indicate retroviruses from two vertebrate groups share common ancestry at terminal nodes, which represent transmission events between hosts without known direction. The numbers show the frequencies of the corresponding transmission events.</p
Phylogenetic relationship of non-avian/mammalian vertebrate ERVs, representative mammalian and avian ERVs, and exogenous retroviruses.
<p>The phylogenetic tree was reconstructed based on the RT protein and by using a maximum likelihood method. The numbers near the selected nodes indicate the aBayes branch supports. Selected retroviruses are labelled near the corresponding external nodes. The hollow circles indicate exogenous retroviruses, whereas the filled circles indicate ERVs. The root was inferred by using Cer1-6 retrotransposons as outgroups. For virus abbreviation, see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007072#ppat.1007072.s004" target="_blank">S1 Table</a>. For lineage I to IV with asterisks, we performed host-retrovirus co-phylogenetic tests in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007072#ppat.1007072.g003" target="_blank">Fig 3</a> and <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1007072#ppat.1007072.t001" target="_blank">Table 1</a>.</p
Mutation analyses of the Sp1-binding site.
<p><b>A.</b> Nucleotide sequence and structural organization of the <i>USP22</i> gene core promoter region. Putative binding sites for the transcriptional factors are underlined. <b>B.</b> Luciferase activity expressed by the Sp1 site-directed mutant and deletion mutants relative to pGL3-basic activity.</p
Primers used in the generation of promoter luciferase constructs.
<p>Primers used in the generation of promoter luciferase constructs.</p