scholarly journals Cyanobacterial Phytochromes in Optogenetics

2021 ◽  
Author(s):  
Sivasankari Sivaprakasam ◽  
Vinoth Mani ◽  
Nagalakshmi Balasubramaniyan ◽  
David Ravindran Abraham
Keyword(s):  
Cell Signaling ◽  
Blue Light ◽  
Neural Circuits ◽  
Spectral Feature ◽  
Cell Aggregation ◽  
Visible Radiation ◽  
Signaling Transduction ◽  
Wide Range ◽  
Yellow Orange

Optogenetics initially used plant photoreceptors to monitor neural circuits, later it has expanded to include engineered plant photoreceptors. Recently photoreceptors from bacteria, algae and cyanobacteria have been used as an optogenetic tool. Bilin-based photoreceptors are common light-sensitive photoswitches in plants, algae, bacteria and cyanobacteria. Here we discuss the photoreceptors from cyanobacteria. Several new photoreceptors have been explored in cyanobacteria which are now proposed as cyanobacteriochrome. The domains in the cyanobacteriochrome, light-induced signaling transduction, photoconversion, are the most attractive features for the optogenetic system. The wider spectral feature of cyanobacteriochrome from UV to visible radiation makes it a light potential sensitive optogenetic tool. Besides, cyanobacterial phytochrome responses to yellow, orange and blue light have more application in optogenetics. This chapter summarizes the photoconversion, phototaxis, cell aggregation, cell signaling mediated by cyanobacteriochrome and cyanophytochrome. As there is a wide range of cyanobacteriochrome and its combination delivers a varied light-sensitive response. Besides coordination among cyanobacteriochromes in cell signaling reduces the engineering of photoreceptors for the optogenetic system.

A review on aversive Pavlovian-to-Instrumental transfer in humans

2020 ◽  
Author(s):  
Anna Gerlicher ◽  
Merel Kindt
Keyword(s):  
Avoidance Behavior ◽  
Neural Circuits ◽  
Transfer Effects ◽  
Future Directions ◽  
Transfer Paradigm ◽  
Wide Range ◽  
Threat Cues ◽  
Imminent Threat ◽  
Fear And Anxiety ◽  
Pathological Anxiety

A cue that indicates imminent threat elicits a wide range of physiological, hormonal, autonomic, cognitive, and emotional fear responses in humans and facilitates threat-specific avoidance behavior. The occurrence of a threat cue can, however, also have general motivational effects and affect behavior. That is, the encounter with a threat cue can increase our tendency to engage in general avoidance behavior that does neither terminate nor prevent the threat-cue or the threat itself. Furthermore, the encounter with a threat-cue can substantially reduce our likelihood to engage in behavior that leads to rewarding outcomes. Such general motivational effects of threat-cues on behavior can be informative about the transition from normal to pathological anxiety and could also explain the development of comorbid disorders, such as depression and substance abuse. Despite the unmistakable relevance of the motivational effects of threat for our understanding of anxiety disorders, their investigation is still in its infancy. Pavlovian-to-Instrumental transfer is one paradigm that allows us to investigate such motivational effects of threat cues. Here, we review studies investigating aversive transfer in humans and discuss recent results on the neural circuits mediating Pavlovian-to-Instrumental transfer effects. Finally, we discuss potential limitations of the transfer paradigm and future directions for employing Pavlovian-to-Instrumental transfer for the investigation of motivational effects of fear and anxiety.

scholarly journals Light- and Melanin Nanoparticle-Induced Cytotoxicity in Metastatic Cancer Cells

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 965
Author(s):  
Victoria R. Gabriele ◽  
Robabeh M. Mazhabi ◽  
Natalie Alexander ◽  
Purna Mukherjee ◽  
Thomas N. Seyfried ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Metastatic Cancer ◽  
Energy Levels ◽  
Nanoparticle Concentration ◽  
Visible Radiation ◽  
Laser Illumination ◽  
Wide Range ◽  
Low Glucose ◽  
Melanin Nanoparticles ◽  
Metastatic Cancer Cells

Melanin nanoparticles are known to be biologically benign to human cells for a wide range of concentrations in a high glucose culture nutrition. Here, we show cytotoxic behavior at high nanoparticle and low glucose concentrations, as well as at low nanoparticle concentration under exposure to (nonionizing) visible radiation. To study these effects in detail, we developed highly monodispersed melanin nanoparticles (both uncoated and glucose-coated). In order to study the effect of significant cellular uptake of these nanoparticles, we employed three cancer cell lines: VM-M3, A375 (derived from melanoma), and HeLa, all known to exhibit strong macrophagic character, i.e., strong nanoparticle uptake through phagocytic ingestion. Our main observations are: (i) metastatic VM-M3 cancer cells massively ingest melanin nanoparticles (mNPs); (ii) the observed ingestion is enhanced by coating mNPs with glucose; (iii) after a certain level of mNP ingestion, the metastatic cancer cells studied here are observed to die—glucose coating appears to slow that process; (iv) cells that accumulate mNPs are much more susceptible to killing by laser illumination than cells that do not accumulate mNPs; and (v) non-metastatic VM-NM1 cancer cells also studied in this work do not ingest the mNPs, and remain unaffected after receiving identical optical energy levels and doses. Results of this study could lead to the development of a therapy for control of metastatic stages of cancer.

scholarly journals Selective 13C labelling reveals the electronic structure of flavocoenzyme radicals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erik Schleicher ◽  
Stephan Rein ◽  
Boris Illarionov ◽  
Ariane Lehmann ◽  
Tarek Al Said ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Blue Light ◽  
Density Functional ◽  
Double Resonance ◽  
Density Functional Theory Calculations ◽  
Microwave Frequency ◽  
Fine Tuning ◽  
Electron Nuclear Double Resonance ◽  
Intermediate Radical ◽  
Wide Range

AbstractFlavocoenzymes are nearly ubiquitous cofactors that are involved in the catalysis and regulation of a wide range of biological processes including some light-induced ones, such as the photolyase-mediated DNA repair, magnetoreception of migratory birds, and the blue-light driven phototropism in plants. One of the factors that enable versatile flavin-coenzyme biochemistry and biophysics is the fine-tuning of the cofactor’s frontier orbital by interactions with the protein environment. Probing the singly-occupied molecular orbital (SOMO) of the intermediate radical state of flavins is therefore a prerequisite for a thorough understanding of the diverse functions of the flavoprotein family. This may be ultimately achieved by unravelling the hyperfine structure of a flavin by electron paramagnetic resonance. In this contribution we present a rigorous approach to obtaining a hyperfine map of the flavin’s chromophoric 7,8-dimethyl isoalloxazine unit at an as yet unprecedented level of resolution and accuracy. We combine powerful high-microwave-frequency/high-magnetic-field electron–nuclear double resonance (ENDOR) with 13C isotopologue editing as well as spectral simulations and density functional theory calculations to measure and analyse 13C hyperfine couplings of the flavin cofactor in DNA photolyase. Our data will provide the basis for electronic structure considerations for a number of flavin radical intermediates occurring in blue-light photoreceptor proteins.

History and experience of a volunteer ambulance first responder scheme in London

2021 ◽  
Vol 13 (8) ◽  
pp. 344-348
Author(s):  
Saman Al-Sahab ◽  
Aditi Nijhawan ◽  
Tim Kirkby ◽  
Shadman Aziz
Keyword(s):  
Cardiac Arrest ◽  
Blue Light ◽  
Response Times ◽  
Ambulance Service ◽  
First Responder ◽  
Emergency Responders ◽  
Life Saving ◽  
Wide Range ◽  
Life Threatening ◽  
Set Up

Emergency responders (ERs) are volunteers who attend category 1 (immediately life-threatening) and category 2 (emergency) 999 calls on behalf of the London Ambulance Service NHS Trust (LAS). ERs aim to arrive first on scene to these incidents to provide essential life-saving interventions prior to the arrival of further ambulance resources. ERs come from a wide range of backgrounds and undergo a thorough selection, training and mentorship process before advancing to working in a two-person ER crew. Compared to most traditional volunteer first responder schemes, the LAS ER scheme, which was set up in 2008, involves an enhanced skillset, dispatch to medical and traumatic emergencies in addition to cardiac arrest, and the use of blue-light vehicles to reduce response times. Over a period of 13 years, the scheme has grown in scope and size, and now operates with more than 120 volunteers based at seven ambulance stations across London.

Inserting a AlN Electron Blocking Layer for InGaN/GaN Blue Light-Emitting Diodes

2020 ◽  
Vol 1014 ◽  
pp. 126-130
Author(s):  
Wan Sheng Zuo ◽  
Yin Xi Niu ◽  
Liu Yang ◽  
Xiu Zhen Chi ◽  
Jin Jin Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
Barrier Layer ◽  
Light Emitting Diodes ◽  
Electrostatic Discharge ◽  
Blocking Layer ◽  
Optical Performance ◽  
Spreading Effect ◽  
Electron Blocking Layer ◽  
Light Emitting ◽  
Wide Range

In this study, the advantages of the AlN electron blocking layer (EBL) for InGaN/GaN blue light-emitting diodes (LEDs) were investigated. The LEDs with the AlN EBL exhibited better optical performance over a wide range of carrier concentration due to the suppression of electron overflow. Furthermore, the AlN EBL with a thicker last barrier layer was investigated. The thicker last barrier layer was used to enhance Electrostatic Discharge (ESD) characteristic by the better current spreading effect.

scholarly journals Colour Classification of 1486 Lakes across a Wide Range of Optical Water Types

2018 ◽  
Vol 10 (8) ◽  
pp. 1273 ◽  
Author(s):  
Moritz Lehmann ◽  
Uyen Nguyen ◽  
Mathew Allan ◽  
Hendrik van der Woerd
Keyword(s):  
Water Quality ◽  
Environmental Control ◽  
Anthropogenic Factors ◽  
Landsat 8 ◽  
Diverse Range ◽  
Water Colour ◽  
Water Types ◽  
Wide Range ◽  
Yellow Orange ◽  
Spatio Temporal

Remote sensing by satellite-borne sensors presents a significant opportunity to enhance the spatio-temporal coverage of environmental monitoring programmes for lakes, but the estimation of classic water quality attributes from inland water bodies has not reached operational status due to the difficulty of discerning the spectral signatures of optically active water constituents. Determination of water colour, as perceived by the human eye, does not require knowledge of inherent optical properties and therefore represents a generally applicable remotely-sensed water quality attribute. In this paper, we implemented a recent algorithm for the retrieval of colour parameters (hue angle, dominant wavelength) and derived a new correction for colour purity to account for the spectral bandpass of the Landsat 8 Operational Land Imager (OLI). We used this algorithm to calculate water colour on almost 45,000 observations over four years from 1486 lakes from a diverse range of optical water types in New Zealand. We show that the most prevalent lake colours are yellow-orange and blue, respectively, while green observations are comparatively rare. About 40% of the study lakes show transitions between colours at a range of time scales, including seasonal. A preliminary exploratory analysis suggests that both geo-physical and anthropogenic factors, such as catchment land use, provide environmental control of lake colour and are promising avenues for future analysis.

scholarly journals Outdoor Cultivation of the Microalga Chlorella vulgaris in a New Photobioreactor Configuration: The Effect of Ultraviolet and Visible Radiation

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1962
Author(s):  
Alcinda P. Lopes ◽  
Francisca M. Santos ◽  
Tânia F. C. V. Silva ◽  
Vítor J. P. Vilar ◽  
José C. M. Pires
Keyword(s):  
Chlorella Vulgaris ◽  
Phosphorus Uptake ◽  
Biomass Productivity ◽  
Nitrogen And Phosphorus ◽  
Visible Radiation ◽  
Microalgal Culture ◽  
Wide Range ◽  
Ultraviolet Irradiance ◽  
Nitrogen And Phosphorus Uptake ◽  
Specific Growth Rates

Microalgae can be a future source of biomass with a wide range of applications, including its use to solve current environmental issues. One of the main variables for microalgal cultivation is the light supply: (i) its intensity that often does not present a uniform spatial distribution inside the culture; (ii) photoperiod; and (iii) spectrum. Therefore, this study aims to evaluate the growth of the microalgae Chlorella vulgaris in a tubular photobioreactor with compound parabolic collectors (CPCs) under outdoor conditions. The effect of ultraviolet and visible radiation on biomass productivity and nutrients (nitrogen and phosphorus) uptake was assessed. The maximum biomass productivity was (5 ± 1) × 10−3 g·L−1·h−1, and the specific growth rates ranged from (1.1 ± 0.3) × 10−2 to (2.0 ± 0.6) × 10−2 h−1. Regarding nutrient uptake, initial removal rates of (0.9 ± 0.4) mg N·L−1·h−1 for nitrogen and (0.17 ± 0.04) mg P·L−1·h−1 for phosphorus were reached. These values increased with visible and ultraviolet irradiance until certain values (143 WVIS·m−2 and 9 WUV·m−2 for biomass productivity; 101 WVIS·m−2 and 6 WUV·m−2 for nutrient removal) and then decreased for higher ones due to the photoinhibition phenomenon. Therefore, the application of CPCs to photobioreactors (PBRs) may be beneficial for microalgal culture in countries with higher latitude (with lower solar irradiance levels).

scholarly journals Quorum Sensing Signal Selectivity and the Potential for Interspecies Cross Talk

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Samantha Wellington ◽  
E. Peter Greenberg
Keyword(s):  
Quorum Sensing ◽  
Cell Signaling ◽  
Cross Talk ◽  
Homoserine Lactone ◽  
Interspecies Interactions ◽  
Interspecies Competition ◽  
Content Type ◽  
E Coli ◽  
Competition And Cooperation ◽  
Wide Range

ABSTRACTMany species of proteobacteria communicate with kin and coordinate group behaviors through a form of cell-cell signaling called acyl-homoserine lactone (AHL) quorum sensing (QS). Most AHL receptors are thought to be specific for their cognate signal, ensuring that bacteria cooperate and share resources only with closely related kin cells. Although specificity is considered fundamental to QS, there are reports of “promiscuous” receptors that respond broadly to nonself signals. These promiscuous responses expand the function of QS systems to include interspecies interactions and have been implicated in both interspecies competition and cooperation. Because bacteria are frequently members of polymicrobial communities, AHL cross talk between species could have profound impacts. To better understand the prevalence of QS promiscuity, we measured the activity of seven QS receptors in their native host organisms. To facilitate comparison of our results to previous studies, we also measured receptor activity using heterologous expression inEscherichia coli. We found that the standardE. colimethods consistently overestimate receptor promiscuity and sensitivity and that overexpression of the receptors is sufficient to account for the discrepancy between native andE. colireporters. Additionally, receptor overexpression resulted in AHL-independent activity inPseudomonas aeruginosa. Using our activation data, we developed a quantitative score of receptor selectivity. We find that the receptors display a wide range of selectivity and that most receptors respond sensitively and strongly to at least one nonself signal, suggesting a broad potential for cross talk between QS systems.IMPORTANCESpecific recognition of cognate signals is considered fundamental to cell signaling circuits as it creates fidelity in the communication system. In bacterial quorum sensing (QS), receptor specificity ensures that bacteria cooperate only with kin. There are examples, however, of QS receptors that respond promiscuously to multiple signals. “Eavesdropping” by these promiscuous receptors can be beneficial in both interspecies competition and cooperation. Despite their potential significance, we know little about the prevalence of promiscuous QS receptors. Further, many studies rely on methods requiring receptor overexpression, which is known to increase apparent promiscuity. By systematically studying QS receptors in their natural parent strains, we find that the receptors display a wide range of selectivity and that there is potential for significant cross talk between QS systems. Our results provide a basis for hypotheses about the evolution and function of promiscuous signal receptors and for predictions about interspecies interactions in complex microbial communities.

scholarly journals The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder I. The Spectral Feature Finder and Catalogue

2020 ◽  
Vol 496 (4) ◽  
pp. 4874-4893 ◽  
Author(s):  
R Hopwood ◽  
I Valtchanov ◽  
L D Spencer ◽  
J Scott ◽  
C Benson ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Signal To Noise Ratio ◽  
Spectral Feature ◽  
Fourier Transform Spectrometer ◽  
Line Flux ◽  
Residual Spectrum ◽  
Source Type ◽  
Complex Process ◽  
Wide Range ◽  
Significant Line

ABSTRACT We provide a detailed description of the Herschel/SPIRE Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF). The FF is an automated process designed to extract significant spectral features from SPIRE FTS data products. Optimizing the number of features found in SPIRE-FTS spectra is challenging. The wide SPIRE-FTS frequency range (447–1568 GHz) leads to many molecular species and atomic fine structure lines falling within the observed bands. As the best spectral resolution of the SPIRE-FTS is ∼1.2 GHz, there can be significant line blending, depending on the source type. In order to find, both efficiently and reliably, features in spectra associated with a wide range of sources, the FF iteratively searches for peaks over a number of signal-to-noise ratio (SNR) thresholds. For each threshold, newly identified features are rigorously checked before being added to the fitting model. At the end of each iteration, the FF simultaneously fits the continuum and features found, with the resulting residual spectrum used in the next iteration. The final FF products report the frequency of the features found and the associated SNRs. Line flux determination is not included as part of the FF products, as extracting reliable line flux from SPIRE-FTS data is a complex process that requires careful evaluation and analysis of the spectra on a case-by-case basis. The FF results are 100 per cent complete for features with SNR greater than 10 and 50–70 per cent complete at SNR of 5. The FF code and all FF products are publicly available via the Herschel Science Archive.

Targeting specific cell signaling transduction pathways by dietary and medicinal phytochemicals in cancer chemoprevention

Toxicology ◽  
2010 ◽  
Vol 278 (2) ◽  
pp. 229-241 ◽  
Author(s):  
Vidushi S. Neergheen ◽  
Theeshan Bahorun ◽  
Ethan Will Taylor ◽  
Ling-Sun Jen ◽  
Okezie I. Aruoma
Keyword(s):  
Cell Signaling ◽  
Cancer Chemoprevention ◽  
Specific Cell ◽  
Signaling Transduction
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