Summary of 16S rRNA gene sequencing of beaver ceacum and feacal samples for bacterial and archaeal diversity analysis.

<p>Summary of 16S rRNA gene sequencing of beaver ceacum and feacal samples for bacterial and archaeal diversity analysis.</p

Average taxonomic summary of the bacteria identified in the ceacum and feaces of beavers at both the phylum and genus level.

<p>A) Average relative abundance of sequences in all ceacum and feaces samples at the phylum level. B) Average relative abundance of sequences in all ceacum and feaces samples at the genus level. Sequences present with < 0.5% relative abundance were pooled into a group labeled “other”.</p

Taxonomic summary of 16S rRNA gene sequences from the ceacum and feaces of each beaver examined in this study.

<p>A) Relative abundance of sequences in the ceacum and feaces of each individual at the phylum level. B) Relative abundance of sequences in the ceacum and feaces of each individual at the genus level. Sequences present with < 0.5% relative abundance were pooled into a group labeled “other”.</p

Principle coordinate analysis (PcoA) of the ceacum (red squares) and feacal (blue circles) microbiomes.

<p>Comparisons were carried out using both qualitative and quantitative measures of alpha and beta diversity. A) PcoA using abundance based Jaccard dissimilarity coefficient, B) PcoA using binary Jaccard dissimilarity coeffiecient, C) PcoA based on weighted UniFrac, D) PcoA based on unweighted UniFrac. The percent variation explained by each principle coordinate is shown.</p

Rarefaction curves showing the A) Observed OTUs, B) Choa1 as a function of sequencing effort.

<p>Sequences from each sample were randomly sub-sampled to the lowest number of sequences contained in all samples (33993 sequences).</p

Luminescent Metal Complexes within Polyelectrolyte Layers: Tuning Electron and Energy Transfer

The electrochemical and photophysical properties of a luminescent metal center, [Os(bpy)3]2+, are significantly modified by encapsulation within a conducting polymer composite film. Cyclic voltammetry reveals that the encapsulation in an inherently conducting polymer, polyaniline (Pani) or polypyrrole (PPy), can dramatically influence the charge-transfer rates between the metal centers. The increased electron transport, most likely mediated through the conducting polymer backbone, significantly enhances the electrochemiluminescence (ECL) efficiency. The increased communication between adjacent metal centers can also result in other interesting properties, such as photoinduced electron-transfer processes. In situ electron spin resonance (ESR) spectroscopy has been used to probe the photo-oxidation of an osmium metal center encapsulated in a PPy composite film. The irradiation of PPy in the presence of the osmium metal center resulted in the photo-oxidation of the Os2+ to Os3+ state and the consequent reduction of the PPy polyelectrolyte. The degree of communication between luminescent metal centers allows the composite properties to be tuned for various applications including ECL sensor devices and light-switching and light-harvesting systems

Hierarchical clustering of microbiomes from ceacum and feaces of 4 beavers.

<p>Distance matrices were generated with A) weighted and B) unweighted UniFrac calculations. Jack knife analysis was used to evaluate the reliability of the clustering results at even sequencing depth. Nodes colored red show 75–100% support, yellow 50–75%, green 25–50% and blue <25% support.</p

Influence of Steric Confinement within Zeolite Y on Photoinduced Energy Transfer between [Ru(bpy)₃]²⁺ and Iron Polypyridyl Complexes

The spectroscopic and photophysical properties of zeolite-Y-entrapped [Ru(bpy)3]2+ co-doped with either [Fe(bpy)3]2+ or [Fe(tpy)2]2+ over a range of iron complex loadings are presented. In solution, [Ru(bpy)3]2+ undergoes efficient bimolecular energy transfer to [Fe(bpy)3]2+, whereas only radiative or trivial energy transfer occurs between [Ru(bpy)3]2+ and [Fe(tpy)2]2+. In sharp contrast, within zeolite Y, both [Fe(bpy)3]2+ and [Fe(tpy)2]2+ were found to effectively quench the donor emission. Fitting the Perrin model to the photophysical data yields an effective quenching radius of 32 and 27 Å, respectively, for [Fe(bpy)3]2+ and [Fe(tpy)2]2+. The long-range nature of the quenching suggests Förster energy transfer. Detailed spectroscopic investigations indicate that [Fe(tpy)2]2+ bound within zeolite Y undergoes significant distortion from octahedral geometry. This distortion results in increased oscillator strength and enhanced spectral overlap, between the [Ru(bpy)3]2+ 3dπ−π* donor emission and the co-incident acceptor 1T2−A1 ligand field absorption compared with solution. This turns on an efficient energy transfer to [Fe(tpy)2]2+ within the confinement of the zeolite Y supercage. Overall, this is an interesting example of the ability of the zeolite environment to provoke new photophysical processes not possible in solution

Label-Free Impedance Detection of Cancer Cells

Ovarian cancer cells, SKOV3, have been immobilized onto platinum microelectrodes using anti-EPCAM capture antibodies and detected with high sensitivity using electrochemical impedance. The change in impedance following cell capture is strongly dependent on the supporting electrolyte concentration. By controlling the concentration of Dulbecco’s phosphate buffered saline (DPBS) electrolyte, the double layer thickness can be manipulated so that the interfacial electric field interacts with the bound cells, rather than simply decaying across the antibody capture layer. Significantly, the impedance changes markedly upon cell capture over the frequency range from 3 Hz to 90 kHz. For example, using an alternating-current (ac) amplitude of 25 mV, a frequency of 81.3 kHz, and an open circuit potential (OCP) as the direct-current (dc) voltage, a detection limit of 4 captured cells was achieved. Assuming an average cell radius of 5 μm, the linear dynamic range is from 4 captured cells to 650 ± 2 captured cells, which is approximately equivalent to fractional coverages from 0.1% to 29%. An equivalent circuit that models the impedance response of the cell capture is discussed

Diversity of Rumen Bacteria in Canadian Cervids

<div><p>Interest in the bacteria responsible for the breakdown of lignocellulosic feedstuffs within the rumen has increased due to their potential utility in industrial applications. To date, most studies have focused on bacteria from domesticated ruminants. We have expanded the knowledge of the microbial ecology of ruminants by examining the bacterial populations found in the rumen of non-domesticated ruminants found in Canada. Next-generation sequencing of 16S rDNA was employed to characterize the liquid and solid-associated bacterial communities in the rumen of elk (<i>Cervus canadensis</i>), and white tailed deer (<i>Odocoileus virginianus</i>). Despite variability in the microbial populations between animals, principle component and weighted UniFrac analysis indicated that bacterial communities in the rumen of elk and white tail deer are distinct. Populations clustered according to individual host animal and not the association with liquid or solid phase of the rumen contents. In all instances, <i>Bacteroidetes</i> and <i>Firmicutes</i> were the dominant bacterial phyla, although the relative abundance of these differed among ruminant species and between phases of rumen digesta, respectively. In the elk samples <i>Bacteroidetes</i> were more predominant in the liquid phase whereas <i>Firmicutes</i> was the most prevalent phyla in the solid digesta (P = 1×10⁻⁵). There were also statistically significant differences in the abundance of OTUs classified as <i>Fibrobacteres</i> (P = 5×10⁻³) and <i>Spirochaetes</i> (P = 3×10⁻⁴) in the solid digesta of the elk samples. We identified a number of OTUs that were classified as phylotypes not previously observed in the rumen environment. Our results suggest that although the bacterial diversity in wild North American ruminants shows overall similarities to domesticated ruminants, we observed a number of OTUs not previously described. Previous studies primarily focusing on domesticated ruminants do not fully represent the microbial diversity of the rumen and studies focusing on non-domesticated ruminants should be expanded.</p></div