Pattern selection of directionally oriented chitosan tubes

The growth of viscoelastic curved materials, inspired by biological systems, may give rise to various complex structures. One of the simplest ways to control the pattern formation is to vary the orientation of the reaction vessel while keeping all other experimental conditions constant. Here, we report the self-organization of soft chitosan tubes by injecting acidic chitosan sol into a pool of sodium hydroxide solution, where the adhesive force between the gel and container keeps the tubules on the bottom of the reactor. The horizontal growth of the tubular structure undergoes spontaneous symmetry breaking, where instabilities develop on the surface of the chitosan tubules. Transformation of folds into wrinkles and finally to a smooth tube takes place by varying the orientation of the container. In addition to characterizing the evolving structures, we have also shown that the linear growth rate of the tube scales with the tilt angle of the container from the horizontal.& nbsp;Published under an exclusive license by AIP Publishing

Taxonomic and Functional Microbial Signatures of the Endemic Marine Sponge Arenosclera brasiliensis

The endemic marine sponge Arenosclera brasiliensis (Porifera, Demospongiae, Haplosclerida) is a known source of secondary metabolites such as arenosclerins A-C. In the present study, we established the composition of the A. brasiliensis microbiome and the metabolic pathways associated with this community. We used 454 shotgun pyrosequencing to generate approximately 640,000 high-quality sponge-derived sequences (∼150 Mb). Clustering analysis including sponge, seawater and twenty-three other metagenomes derived from marine animal microbiomes shows that A. brasiliensis contains a specific microbiome. Fourteen bacterial phyla (including Proteobacteria, Cyanobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Cloroflexi) were consistently found in the A. brasiliensis metagenomes. The A. brasiliensis microbiome is enriched for Betaproteobacteria (e.g., Burkholderia) and Gammaproteobacteria (e.g., Pseudomonas and Alteromonas) compared with the surrounding planktonic microbial communities. Functional analysis based on Rapid Annotation using Subsystem Technology (RAST) indicated that the A. brasiliensis microbiome is enriched for sequences associated with membrane transport and one-carbon metabolism. In addition, there was an overrepresentation of sequences associated with aerobic and anaerobic metabolism as well as the synthesis and degradation of secondary metabolites. This study represents the first analysis of sponge-associated microbial communities via shotgun pyrosequencing, a strategy commonly applied in similar analyses in other marine invertebrate hosts, such as corals and algae. We demonstrate that A. brasiliensis has a unique microbiome that is distinct from that of the surrounding planktonic microbes and from other marine organisms, indicating a species-specific microbiome

The Effect of Halide Composition on the Luminescent Properties of Ternary Cesium–Copper Halide Pseudo-Perovskite Films

Ternary copper halide pseudo-perovskites are in the forefront of research as potential active materials in light emission applications. The optoelectronic properties of these compounds can be fine-tuned by the preparation of mixed-halide compositions. After irradiation, self-trapped excitonic states are formed in these materials. However, the emission from these self-trapped states is not yet fully understood. In this work, mixed-halide Cs3 Cu2 X5 films (where X: I and/or Br) are prepared by a simple spray-coating method. Using ultraviolet photoelectron spectroscopy, the changes in optoelectronic properties are linked to the electronic structure of these materials. It is revealed that the incorporation of bromide into the lattice makes the emission process of these materials more vulnerable to trap states. By combining the different spectroscopic characterization techniques, the exact band structure of these compounds is determined, and the different processes are translated to the absolute energy scale. As an alternative excitation mechanism of self-trapped states

Relative functional contributions that differed significantly between the dominant proteobacterial groups.

<p>The first column shows each pair of organisms (e.g., <i>Alpha</i>- and <i>Gammaproteobacteria</i>) that differed significantly (p-value <0.05) for a subsystem (e.g., “metabolism of aromatic compounds”), detected using ANOVA for multiple groups. The percentage bars were colored as follows: <i>Alphaproteobacteria</i> (blue); <i>Gammaproteobacteria</i> (orange); <i>Betaproteobacteria</i> (green), <i>Burkholderiales</i> (purple); bacteria (light blue); and total species (red). The second column shows the detected differences with the 90% confidence interval, as calculated using the Tukey-Kramer post-hoc test.</p

Bacterial orders that were significantly overrepresented in sponge or seawater metagenomes.

<p>Organismal classifications differing significantly (p-value <0.00001) were indicated by direct Poisson model-based comparisons of the two groups of metagenomes.</p

Relative abundances of bacterial phyla and proteobacterial classes (<i>inset</i>) in the sponge and seawater organismal classifications.

<p>Asterisks indicate organisms differing significantly (p-value <0.00001) between groups based on direct Poisson model-based comparisons.</p

Comparison of the metagenomes of marine organism-associated microbiomes.

<p>(A) Cladogram representing the similarities in the taxonomic profiles of the best BLASTn hits for the reads. (B) Cladogram representing the fraction of cross-contigs (i.e., shared contigs that contain reads from two or more metagenomes) after cross-assembly. We used available shotgun metagenomic samples from the Australian sponge <i>Cymbastela concentrica</i> [PMID: 20520651], healthy and morbid fish [PMID: 18337718], the mussel species <i>Mytilus galloprovincialis</i> and <i>M. edulis</i> [PMID: 20111607] and a whale fall [PMID: 15845853]. Four water samples are included for comparison: two from this study and two from a study on <i>C. concentrica</i> [PMID: 20520651]. Cladograms were created with BioNJ <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039905#pone.0039905-Gascuel1" target="_blank">[34]</a>, as explained in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039905#s2" target="_blank">Materials and Methods</a> section.</p