Förster Resonance Energy Transfer between Core/Shell Quantum Dots and Bacteriorhodopsin

An energy transfer relationship between core-shell CdSe/ZnS quantum dots (QDs) and the optical protein bacteriorhodopsin (bR) is shown, demonstrating a distance-dependent energy transfer with 88.2% and 51.1% of the QD energy being transferred to the bR monomer at separation distances of 3.5 nm and 8.5 nm, respectively. Fluorescence lifetime measurements isolate nonradiative energy transfer, other than optical absorptive mechanisms, with the effective QD excited state lifetime reducing from 18.0 ns to 13.3 ns with bR integration, demonstrating the Förster resonance energy transfer contributes to 26.1% of the transferred QD energy at the 3.5 nm separation distance. The established direct energy transfer mechanism holds the potential to enhance the bR spectral range and sensitivity of energies that the protein can utilize, increasing its subsequent photocurrent generation, a significant potential expansion of the applicability of bR in solar cell, biosensing, biocomputing, optoelectronic, and imaging technologies

Increased appendicularian zooplankton alter carbon cycling under warmer more acidified ocean conditions

Anthropogenic atmospheric loading of CO2 raises concerns about combined effects of increasing ocean temperature and acidification, on biological processes. In particular, the response of appendicularian zooplankton to climate change may have significant ecosystem implications as they can alter biogeochemical cycling compared to classical copepod dominated food webs. However, the response of appendicularians to multiple climate drivers and effect on carbon cycling are still not well understood. Here, we investigated how gelatinous zooplankton (appendicularians) affect carbon cycling of marine food webs under conditions predicted by future climate scenarios. Appendicularians performed well in warmer conditions and benefited from low pH levels, which in turn altered the direction of carbon flow. Increased appendicularians removed particles from the water column that might otherwise nourish copepods by increasing carbon transport to depth from continuous discarding of filtration houses and fecal pellets. This helps to remove CO2 from the atmosphere, and may also have fisheries implications

DNA Persistence in a Sink Drain Environment.

Biofilms are organized structures composed mainly of cells and extracellular polymeric substances produced by the constituent microorganisms. Ubiquitous in nature, biofilms have an innate ability to capture and retain passing material and may therefore act as natural collectors of contaminants or signatures of upstream activities. To determine the persistence and detectability of DNA passing through a sink drain environment, Bacillus anthracis strain Ames35 was cultured (6.35 x 107 CFU/mL), sterilized, and disposed of by addition to a sink drain apparatus with an established biofilm. The sink drain apparatus was sampled before and for several days after the addition of the sterilized B. anthracis culture to detect the presence of B. anthracis DNA. Multiple PCR primer pairs were used to screen for chromosomal and plasmid DNA with primers targeting shorter sequences showing greater amplification efficiency and success. PCR amplification and detection of target sequences indicate persistence of chromosomal DNA and plasmid DNA in the biofilm for 5 or more and 14 or more days, respectively

Digital capillary electrophoresis gel image from LabChip GX acquired using HT DNA Hi Sens(itivity) Reagent Kit.

<p>Sample wells contain, from left to right: LabChip GX Ladder, No-Template Control, Control Isolated <i>Bacillus anthracis</i> strain Ames35 DNA, Day 1 Autoclaved Sample prior to disposal, Day 1 Bleached Sample prior to disposal, 6-round 1 testing samples (Day 2, Day 3, Day 5, Day 6, Day 10 & Day 14 Samples.), and 4-round 2 testing samples (Day 3, Day 11, Day 21 & Day 22 Samples). Duplicate PCR amplification sample data for each time point obtained, but not shown.</p

Sampling tips with female tap ends to attach to the tip of the sampling device.

<p>Various sample materials shown, from left to right: copper wire, nylon fibers, and polyether foam.</p

Primers utilized for <i>Bacillus anthracis</i> & eubacteria DNA amplification and the expected amplicons.

<p>Primers utilized for <i>Bacillus anthracis</i> & eubacteria DNA amplification and the expected amplicons.</p

Agarose gel images for <i>Bacillus anthracis</i> PCR samples.

<p>Depicted in A, from left to right, is 100 bp ladder, no-template control (NTC) and 3 reactions utilizing BA-5449 primer set, NTC and 3 reactions utilizing <i>cya</i>-1 primer set, NTC and 3 reactions utilizing <i>PA</i>7/6 primer set and 100 bp ladder. Depicted in B, from left to right, are duplicate reactions with bleached <i>Bacillus anthracis</i> template material and duplicate reactions with autoclaved <i>Bacillus anthracis</i> template material, with all 4 reactions utilizing the ITSeub primer pair.</p

Design strategies and applications of biomaterials and devices for Hernia repair

Hernia repair is one of the most commonly performed surgical procedures worldwide, with a multi-billion dollar global market. Implant design remains a critical challenge for the successful repair and prevention of recurrent hernias, and despite significant progress, there is no ideal mesh for every surgery. This review summarizes the evolution of prostheses design toward successful hernia repair beginning with a description of the anatomy of the disease and the classifications of hernias. Next, the major milestones in implant design are discussed. Commonly encountered complications and strategies to minimize these adverse effects are described, followed by a thorough description of the implant characteristics necessary for successful repair. Finally, available implants are categorized and their advantages and limitations are elucidated, including non-absorbable and absorbable (synthetic and biologically derived) prostheses, composite prostheses, and coated prostheses. This review not only summarizes the state of the art in hernia repair, but also suggests future research directions toward improved hernia repair utilizing novel materials and fabrication methods

Quantum dot enhancement of bacteriorhodopsin-based electrodes

Nanoscale sensing arrays utilizing the unique properties of the optical protein bacteriorhodopsin and colloidal semiconductor quantum dots are being developed for toxin detection applications. This paper describes an innovative method to activate bacteriorhodopsin-based electrodes with the optical output of quantum dots, producing an enhanced electrical response from the protein. Results show that the photonic emission of CdSe/ZnS quantum dots is absorbed by the bacteriorhodopsin retinal and initiates the proton pumping sequence, resulting in an electrical output from a bacteriorhodopsin-based electrode. It is also shown that activated quantum dots in sub-10 nm proximity to bacteriorhodopsin further amplify the photovoltaic response of the protein by approximately 23%, compared to without attached quantum dots, suggesting direct energy transfer mechanisms beyond photonic emission alone. The ability of quantum dots to activate nanoscale regions on bacteriorhodopsin-based electrodes could allow sub-micron sensing arrays to be created due to the ability to activate site-specific regions on the array. © 2009 Elsevier B.V