16S rRNA gene sequencing statistics from normal and L2-treated C57BL/6 mice.

<p>16S rRNA gene sequencing statistics from normal and L2-treated C57BL/6 mice.</p

Family-level comparison of fecal microbiota in normal (N) and L2-treated mice (Na).

<p>Mann Whitney test.</p><p>*, P<0.05</p><p>**, P<0.01.</p><p>Family-level comparison of fecal microbiota in normal (N) and L2-treated mice (Na).</p

<i>Lentinula edodes</i>-Derived Polysaccharide Alters the Spatial Structure of Gut Microbiota in Mice

<div><p><i>Lentinula edodes</i>-derived polysaccharides possess many therapeutic characteristics, including anti-tumor and immuno-modulation. The gut microbes play a critical role in modulation of immune function. However, the impact of <i>Lentinula edodes</i>-derived polysaccharides on the gut microbes have not yet been explored. In this study, high-throughput pyrosequencing technique was employed to investigate the effects of a new heteropolysaccharide L2 from <i>Lentinula edodes</i> on microbiota diversity and composition of small intestine, cecum, colon and distal end of colon (feces) in mice. The results demonstrated that along mouse intestine the microbiota exhibit distinctly different space distribution. L2 treatment reduced the diversity and evenness of gut microbiota along the intestine, especially in the cecum and colon. In the fecal microbial communities, the decrease of Bacteroidetes by significantly increasing Proteobacteria were observed, which were characterized by the increased <i>Helicobacteraceae</i> and reduced S24-7 at family level. Some OTUs, corresponding to <i>Bacteroides acidifaciens</i>, <i>Alistipes</i> and <i>Helicobacter suncus</i>, were found to be significantly increased in L2 treated-mice. In particular, 4 phyla Chloroflexi, Gemmatimonadetes, Nitrospirae and Planctomycetes are exclusively present in L2-treated mice. This is helpful for further demonstrating healthy action mechanism of <i>Lentinula edodes</i>-derived polysaccharide L2.</p></div

Salt effects on knot dynamics in polyelectrolyte solutions

We study the dynamics of linear polyelectrolyte (PE) knot in solution with doping salt by molecular dynamics simulations. The molecular mechanisms of PE knot dynamics are explained. The knot dynamics are the coupling results by the moving effect of chain entanglement and by the breathing effect of knot fluctuations. The moving effect is important as the whole chain is in the random coil state and becomes weak as shrinking to the close-to-globule (CTG) state. Interestingly, as the chain in the CTG state, the knot swells with occupying more segments. The breathing effect dominates the knot dynamics in the CTG state. This nontrivial behaviour (in comparison to neutral polymer knot) is prominent for the cases of doping salt with high concentration or of doping high-valent salt, which attributes to the enhanced electrostatic interactions and long-range fluctuation effects.</p

Alpha diversity of fecal microbiota in normal (N) and L2-treated mice (Na).*, p<0.05;**p<0.01.

<p>The index of evenness (J indices) was calculated with the formula E = H/ln(S), where H is the Shannon index and S is the number of OTU in that animal. </p

New Nanostructure in a Metastable Ice Phase

Hydrogen bonds between water molecules can form a polygonal structure, which determine the physical properties of different ice phases. Pure pentagonal rings are not stable in crystal ice. In this work, we discover a new nanostructure of ice in heterogeneous nucleation on metal surfaces by molecular dynamic simulation. In this nanostructure, pentagonal rings are connected by dodecahedrons and staggered hydrogen bonds. The presence of dodecahedrons could help the stability of ice structure with pentagons. This nanostructure serves as a skeleton unit in ice. Our results provide a new explanation for the existence of pentagonal rings in ice, which are helpful to understand the complex ice phase behaviors

Comparison of small intestine (A), cecum (B) and colon (C) microbiota at phylum level.

<p>Comparison of small intestine (A), cecum (B) and colon (C) microbiota at phylum level. </p

Clustering (A) and weighted unifrac PCA (B) analysis of fecal microbiota, as well as OTUs overlaps of a L2-treated mice Na4 (C) and a normal mice N4 (D) along the intestinal tract.

<p>Clustering (A) and weighted unifrac PCA (B) analysis of fecal microbiota, as well as OTUs overlaps of a L2-treated mice Na4 (C) and a normal mice N4 (D) along the intestinal tract.</p

Phylum-level comparison of fecal microbiota in normal (N) and L2-treated mice (Na).

<p>Mann Whitney test.</p><p>Phylum-level comparison of fecal microbiota in normal (N) and L2-treated mice (Na).</p