scholarly journals Light exposure decreases infectivity of the Daphnia parasite Pasteuria ramosa

2019 ◽  
Author(s):  
Erin P. Overholt ◽  
Meghan A. Duffy ◽  
Matthew P. Meeks ◽  
Taylor H. Leach ◽  
Craig E. Williamson
Keyword(s):  
Visible Light ◽  
Light Exposure ◽  
Disease Outbreaks ◽  
Light Sensitivity ◽  
Biologically Relevant ◽  
Light Regimes ◽  
Bacterial Endospores ◽  
Pasteuria Ramosa ◽  
Aquatic Pathogens ◽  
Laboratory Exposure

ABSTRACTClimate change is altering light regimes in lakes, which should impact disease outbreaks, since sunlight can harm aquatic pathogens. However, some bacterial endospores are resistant to damage from light, even surviving exposure to UV-C. We examined the sensitivity of Pasteuria ramosa endospores, an aquatic parasite infecting Daphnia zooplankton, to biologically relevant wavelengths of light. Laboratory exposure to increasing intensities of UV-B, UV-A, and visible light significantly decreased P. ramosa infectivity, though there was no effect of spore exposure on parasitic castration of the host. P. ramosa is more sensitive than its Daphnia host to damage by longer wavelength UV-A and visible light; this may enable Daphnia to seek an optimal light environment in the water column where both UV-B damage and parasitism are minimal. Studies of pathogen light sensitivity help us uncover factors controlling epidemics in lakes, which is especially important given that water transparency is decreasing in many lakes.

scholarly journals Light exposure decreases infectivity of the Daphnia parasite Pasteuria ramosa

2020 ◽  
Vol 42 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Erin P Overholt ◽  
Meghan A Duffy ◽  
Matthew P Meeks ◽  
Taylor H Leach ◽  
Craig E Williamson
Keyword(s):  
Visible Light ◽  
Light Exposure ◽  
Disease Outbreaks ◽  
Light Sensitivity ◽  
Biologically Relevant ◽  
Light Regimes ◽  
Bacterial Endospores ◽  
Pasteuria Ramosa ◽  
Aquatic Pathogens ◽  
Laboratory Exposure

Abstract Climate change is altering light regimes in lakes, which should impact disease outbreaks, since sunlight can harm aquatic pathogens. However, some bacterial endospores are resistant to damage from light, even surviving exposure to UV-C. We examined the sensitivity of Pasteuria ramosa endospores, an aquatic parasite infecting Daphnia zooplankton, to biologically relevant wavelengths of light. Laboratory exposure to increasing intensities of UV-B, UV-A, and visible light significantly decreased P. ramosa infectivity, though there was no effect of spore exposure on parasitic castration of infected hosts. P. ramosa is more sensitive than its Daphnia host to damage by longer wavelength UV-A and visible light; this may enable Daphnia to seek an optimal light environment in the water column, where both UV-B damage and parasitism are minimal. Studies of pathogen light sensitivity help us to uncover factors controlling epidemics in lakes, which is especially important given that water transparency is decreasing in many lakes.

Tuning the Photocatalytic Performance of Plasmonic Nanocomposites (ZnO/Aux) Driven in Visible Light

2019 ◽  
Vol 8 (1) ◽  
pp. 56-61
Author(s):  
Aneeya K. Samantara ◽  
Debasrita Dash ◽  
Dipti L. Bhuyan ◽  
Namita Dalai ◽  
Bijayalaxmi Jena
Keyword(s):  
Electron Transfer ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Transfer Rate ◽  
Photocatalytic Performance ◽  
Light Exposure ◽  
Au Nanoparticle ◽  
Electron Transfer Rate ◽  
Au Nps ◽  
Zno Nanostructure

: In this article, we explored the possibility of controlling the reactivity of ZnO nanostructures by modifying its surface with gold nanoparticles (Au NPs). By varying the concentration of Au with different wt% (x = 0.01, 0.05, 0.08, 1 and 2), we have synthesized a series of (ZnO/Aux) nanocomposites (NCs). A thorough investigation of the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface has been carried out. It was observed that ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity among all concentrations of Au on the ZnO surface, which degrades the dye concentration within 2 minutes of visible light exposure. It was further revealed that with an increase in the size of plasmonic nanoparticles beyond 0.08%, the accessible surface area of the Au nanoparticle decreases. The photon absorption capacity of Au nanoparticle decreases beyond 0.08% resulting in a decrease in electron transfer rate from Au to ZnO and a decrease of photocatalytic activity. Background: Due to the industrialization process, most of the toxic materials go into the water bodies, affecting the water and our ecological system. The conventional techniques to remove dyes are expensive and inefficient. Recently, heterogeneous semiconductor materials like TiO2 and ZnO have been regarded as potential candidates for the removal of dye from the water system. Objective: To investigate the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface and the effect of the size of Au NPs for photocatalytic performance in the degradation process. Methods: A facile microwave method has been adopted for the synthesis of ZnO nanostructure followed by a reduction of gold salt in the presence of ZnO nanostructure to form the composite. Results: ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity which degrades the dye concentration within 2 minutes of visible light exposure. The schematic mechanism of electron transfer rate was discussed. Conclusion: Raspberry shaped ZnO nanoparticles modified with different percentages of Au NPs showed good photocatalytic behavior in the degradation of dye molecules. The synergetic effect of unique morphology of ZnO and well anchored Au nanostructures plays a crucial role.

Metal‐Free and Heterogeneous Photocatalytic Reduction of 4‐Nitroaniline by a Poly(Ethylene Glycol)‐Supported Eosin Dye under Visible‐Light Exposure

ChemCatChem ◽  
2019 ◽  
Vol 11 (14) ◽  
pp. 3307-3317
Author(s):  
Andreea L. Chibac ◽  
Violeta Melinte ◽  
Vlasta Brezová ◽  
Estelle Renard ◽  
Arnaud Brosseau ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Visible Light ◽  
Light Exposure ◽  
Photocatalytic Reduction ◽  
Poly Ethylene Glycol ◽  
Metal Free ◽  
Poly Ethylene

scholarly journals Efficient 3D printing via photooxidation of ketocoumarin based photopolymerization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoyu Zhao ◽  
Ye Zhao ◽  
Ming-De Li ◽  
Zhong’an Li ◽  
Haiyan Peng ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Visible Light ◽  
Light Exposure ◽  
Three Dimensional ◽  
3D Printer ◽  
Light Penetration ◽  
Viable Solution

AbstractPhotopolymerization-based three-dimensional (3D) printing can enable customized manufacturing that is difficult to achieve through other traditional means. Nevertheless, it remains challenging to achieve efficient 3D printing due to the compromise between print speed and resolution. Herein, we report an efficient 3D printing approach based on the photooxidation of ketocoumarin that functions as the photosensitizer during photopolymerization, which can simultaneously deliver high print speed (5.1 cm h−1) and high print resolution (23 μm) on a common 3D printer. Mechanistically, the initiating radical and deethylated ketocoumarin are both generated upon visible light exposure, with the former giving rise to rapid photopolymerization and high print speed while the latter ensuring high print resolution by confining the light penetration. By comparison, the printed feature is hard to identify when the ketocoumarin encounters photoreduction due to the increased lateral photopolymerization. The proposed approach here provides a viable solution towards efficient additive manufacturing by controlling the photoreaction of photosensitizers during photopolymerization.

scholarly journals Visible-Light Photoswitching of G-Quadruplex Ligand Binding Mode Allows Reversible Control of G-Tetrad Structure

2020 ◽  
Author(s):  
Michael O'Hagan ◽  
Javier Ramos Soriano ◽  
Susanta Haldar ◽  
Juan Carlos Morales ◽  
Adrian Mulholland ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Visible Light ◽  
Uv Light ◽  
Binding Mode ◽  
High Energy ◽  
Light Sources ◽  
Biologically Relevant ◽  
G Quadruplex ◽  
Potential Applications ◽  
Robust Regulation

<div><p>Photoresponsive ligands for G-quadruplex oligonucleotides (G4) offer exciting opportunities for the reversible regulation of these assemblies with potential applications in biological chemistry and responsive nanotechnology. However, achieving the robust regulation of G4 ligand activity with low-energy visible light sources that are easily accessible and compatible with biological systems remains a significant challenge to realizing these applications. Herein, we report the G4-binding properties of a photoresponsive dithienylethene (DTE). We demonstrate the first example of G4-specific acceleration of the photoswitching kinetics of a small molecule and the visible-light mediated switching of the G4 ligand binding mode in physiologically-relevant conditions, which in turn allows control over the G4 tetrad structure of telomeric G4 in potassium buffer. The process is fully reversible and avoids the need for high-energy UV light. This affords an efficient, practical and biologically-relevant means of control that may be applied in the generation of new responsive G4/ligand supramolecular systems.</p></div><br>

scholarly journals Synergistic Antibacterial Performance of a Cu/WO<sub>3</sub>-Added PTFE Particulate Superhydrophobic Composite under Visible-Light Exposure

2012 ◽  
Vol 03 (04) ◽  
pp. 421-430 ◽  
Author(s):  
Yanyan Yao ◽  
Kentaro Yamauchi ◽  
Goro Yamauchi ◽  
Tsuyoshi Ochiai ◽  
Taketoshi Murakami ◽  
...  
Keyword(s):  
Visible Light ◽  
Light Exposure ◽  
Antibacterial Performance

Visible-light assisted methylene blue (MB) removal by novel TiO2/adsorbent nanocomposites

2010 ◽  
Vol 61 (11) ◽  
pp. 2863-2871 ◽  
Author(s):  
Wei Zhang ◽  
Linda Zou ◽  
Lianzhou Wang
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Cost Effective ◽  
Light Sensitivity ◽  
Wet Chemical Method ◽  
Adsorption Ability ◽  
Synergistic Interactions ◽  
Dissolved Organic Compounds ◽  
Wet Chemical ◽  
Chemical Procedure

In present work, visible light sensitive TiO2/adsorbent nanocomposites (TNC) were prepared via a facile wet chemical method. Three types of adsorbents including zeolites (F-9, HSZ-690 and HSZ-930), mesoporous silica (MPS-2.7 and 4) and activated carbon, were used as the porous substrates for nanocomposites. Visible light sensitivity was incorporated to TNCs by nitrogen doping of TiO2, which is obtained through the addition of a nitrogen precursor, triethylamine, within the same wet chemical procedure. The photocatalytic and adsorption ability of as-prepared TNC resultants were studied using solutions of methylene blue (MB) as a model pollutant. Synergistic interactions between adsorption and visible-light photocatalysis were observed, as under the assistance of visible-light irradiation all TNCs achieved higher MB removal rates than those by adsorption process alone. The better performance of the as-prepared N-doped TNC reveals its potential to be used for cost effective solar photocatalytic degradation of dissolved organic compounds.

Visible light induced degradation of pollutant dyes using a self-assembled graphene oxide–molybdenum oxo-bis(dithiolene) composite

2018 ◽  
Vol 42 (17) ◽  
pp. 14229-14238 ◽  
Author(s):  
Joyee Mitra ◽  
Manav Saxena ◽  
Navendu Paul ◽  
Ekata Saha ◽  
Rudra Sarkar ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Visible Light ◽  
Rose Bengal ◽  
Rhodamine B ◽  
Light Exposure ◽  
Rose Bengal Dye ◽  
Self Assembled

An easily separable graphene oxide–molybdenum oxo-bis(dithiolene) ([Ph4P]2[MoO(S2C2(CN)2)2]) composite degraded Rhodamine B and Rose Bengal dye upon visible light exposure.

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