Time-Resolved Activation of pH Sensing and Imaging in Vivo by a Remotely Controllable DNA Nanomachine

Nano Letters ◽  
2019 ◽  
Vol 20 (2) ◽  
pp. 874-880 ◽  
Author(s):  
Jian Zhao ◽  
Yinghao Li ◽  
Mingming Yu ◽  
Zhanjun Gu ◽  
Lele Li ◽  
...  
Keyword(s):  
Ph Sensing ◽  
Time Resolved ◽  
Dna Nanomachine

scholarly journals Time-resolved fluorescence analysis of LHCII in the presence of PsbS at neutral and low pH

2018 ◽  
Author(s):  
Emanuela Crisafi ◽  
Maithili Krishnan ◽  
Anjali Pandit
Keyword(s):  
Lipid Membranes ◽  
Light Stress ◽  
Fluorescence Analysis ◽  
Low Ph ◽  
Photochemical Quenching ◽  
Ph Sensing ◽  
Fluorescence Lifetimes ◽  
Light Harvesting Complexes ◽  
Time Resolved

In plant chloroplast membranes, non-photochemical quenching (NPQ) is activated as a response to a low luminal pH and controlled by the pH-sensing protein PsbS. It has been proposed that PsbS directly interacts with the light-harvesting complexes (LHCII) of Photosystem II, inducing quenching of LHCII Chl excitations, whilst others proposed that PsbS has an indirect role in controlling the organization of the membrane. In this study, we systematically test the influence of low pH and PsbS on the fluorescence lifetimes of membrane-embedded spinach LHCII. The proteoliposome preparations contain LHCII in mild quenched states, aimed to mimic fluorescence conditions of dark-adapted leaves. We find that under those conditions, acidification and the presence of PsbS do not have significant effect on the LHCII Chl fluorescence lifetimes. This supports a view in which the functional role of PsbS consists of re-organizing the thylakoid membrane under light stress, rather than creating direct quencher states. The dimeric form of PsbS appears to be destabilized in lipid membranes compared to detergent micelles, which might explain why the low-pH PsbS crystal structure is dimeric, while in vivo activation of PsbS has been correlated with its monomerization at low pH.

scholarly journals Real-time observation of tetrapyrrole binding to an engineered bacterial phytochrome

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yusaku Hontani ◽  
Mikhail Baloban ◽  
Francisco Velazquez Escobar ◽  
Swetta A. Jansen ◽  
Daria M. Shcherbakova ◽  
...  
Keyword(s):  
Real Time ◽  
Rational Design ◽  
Near Infrared ◽  
Fluorescent Proteins ◽  
Covalent Bond ◽  
Binding Pocket ◽  
Tissue Imaging ◽  
Covalent Attachment ◽  
Time Resolved

AbstractNear-infrared fluorescent proteins (NIR FPs) engineered from bacterial phytochromes are widely used for structural and functional deep-tissue imaging in vivo. To fluoresce, NIR FPs covalently bind a chromophore, such as biliverdin IXa tetrapyrrole. The efficiency of biliverdin binding directly affects the fluorescence properties, rendering understanding of its molecular mechanism of major importance. miRFP proteins constitute a family of bright monomeric NIR FPs that comprise a Per-ARNT-Sim (PAS) and cGMP-specific phosphodiesterases - Adenylyl cyclases - FhlA (GAF) domain. Here, we structurally analyze biliverdin binding to miRFPs in real time using time-resolved stimulated Raman spectroscopy and quantum mechanics/molecular mechanics (QM/MM) calculations. Biliverdin undergoes isomerization, localization to its binding pocket, and pyrrolenine nitrogen protonation in <1 min, followed by hydrogen bond rearrangement in ~2 min. The covalent attachment to a cysteine in the GAF domain was detected in 4.3 min and 19 min in miRFP670 and its C20A mutant, respectively. In miRFP670, a second C–S covalent bond formation to a cysteine in the PAS domain occurred in 14 min, providing a rigid tetrapyrrole structure with high brightness. Our findings provide insights for the rational design of NIR FPs and a novel method to assess cofactor binding to light-sensitive proteins.

Design and in vivo evaluation of alginate-based pH-sensing electrospun wound dressing containing anthocyanins

2021 ◽  
Vol 28 (2) ◽  
Author(s):  
Ayben Pakolpakçıl ◽  
Bilgen Osman ◽  
Gökhan Göktalay ◽  
Elif Tümay Özer ◽  
Yasemin Şahan ◽  
...  
Keyword(s):  
Wound Dressing ◽  
Ph Sensing ◽  
In Vivo Evaluation

scholarly journals Influence of Oxidative Stress on Time-Resolved Oxygen Detection by [Ru(Phen)3]2+ In Vivo and In Vitro

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 485
Author(s):  
Veronika Huntosova ◽  
Denis Horvath ◽  
Robert Seliga ◽  
Georges Wagnieres
Keyword(s):  
Oxidative Stress ◽  
Tissue Oxygenation ◽  
Intact Cell ◽  
Molecular Probes ◽  
Stress Factors ◽  
Time Resolved ◽  
Invasive Approach ◽  
Oxygen Detection

Detection of tissue and cell oxygenation is of high importance in fundamental biological and in many medical applications, particularly for monitoring dysfunction in the early stages of cancer. Measurements of the luminescence lifetimes of molecular probes offer a very promising and non-invasive approach to estimate tissue and cell oxygenation in vivo and in vitro. We optimized the evaluation of oxygen detection in vivo by [Ru(Phen)3]2+ in the chicken embryo chorioallantoic membrane model. Its luminescence lifetimes measured in the CAM were analyzed through hierarchical clustering. The detection of the tissue oxygenation at the oxidative stress conditions is still challenging. We applied simultaneous time-resolved recording of the mitochondrial probe MitoTrackerTM OrangeCMTMRos fluorescence and [Ru(Phen)3]2+ phosphorescence imaging in the intact cell without affecting the sensitivities of these molecular probes. [Ru(Phen)3]2+ was demonstrated to be suitable for in vitro detection of oxygen under various stress factors that mimic oxidative stress: other molecular sensors, H2O2, and curcumin-mediated photodynamic therapy in glioma cancer cells. Low phototoxicities of the molecular probes were finally observed. Our study offers a high potential for the application and generalization of tissue oxygenation as an innovative approach based on the similarities between interdependent biological influences. It is particularly suitable for therapeutic approaches targeting metabolic alterations as well as oxygen, glucose, or lipid deprivation.

scholarly journals Anti-quenching NIR-II molecular fluorophores for in vivo high-contrast imaging and pH sensing

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shangfeng Wang ◽  
Yong Fan ◽  
Dandan Li ◽  
Caixia Sun ◽  
Zuhai Lei ◽  
...  
Keyword(s):  
Ph Sensing ◽  
High Contrast ◽  
Contrast Imaging ◽  
High Contrast Imaging

scholarly journals A Versatile Setup for Time-Resolved Functional Near Infrared Spectroscopy Based on Fast-Gated Single-Photon Avalanche Diode and on Four-Wave Mixing Laser

2019 ◽  
Vol 9 (11) ◽  
pp. 2366 ◽  
Author(s):  
Laura Di Sieno ◽  
Alberto Dalla Mora ◽  
Alessandro Torricelli ◽  
Lorenzo Spinelli ◽  
Rebecca Re ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Single Photon ◽  
Wave Mixing ◽  
Functional Near Infrared Spectroscopy ◽  
Time Resolved ◽  
Diffusive Medium ◽  
Spectroscopy System

In this paper, a time-domain fast gated near-infrared spectroscopy system is presented. The system is composed of a fiber-based laser providing two pulsed sources and two fast gated detectors. The system is characterized on phantoms and was tested in vivo, showing how the gating approach can improve the contrast and contrast-to-noise-ratio for detection of absorption perturbation inside a diffusive medium, regardless of source-detector separation.

In vivo high-contrast visualization of upconversion nanoparticle labeled virus using time-resolved approach

Nano Today ◽  
2021 ◽  
Vol 40 ◽  
pp. 101264
Author(s):  
Gaoju Pang ◽  
Yingying Zhang ◽  
Xiaoyong Wang ◽  
Huizhuo Pan ◽  
Xinyu Zhang ◽  
...  
Keyword(s):  
High Contrast ◽  
Time Resolved

scholarly journals Fiber-Optic Time-Resolved Fluorescence Sensor for in Vitro Serotonin Determination

1993 ◽  
Vol 47 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Stephane Mottin ◽  
Canh Tran-Minh ◽  
Pierre Laporte ◽  
Raymond Cespuglio ◽  
Michel Jouvet
Keyword(s):  
Chemical Sensor ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Excitation Wavelength ◽  
Nitrogen Laser ◽  
Time Resolved ◽  
Temporal Effects ◽  
Starting Point

At pH 7 and with the excitation at wavelengths above 315 nm, previously unreported fluorescence of 5-HT (5-hydroxytryptamine) is observed. Two fluorescence bands were observed for 5-HT; the first emits at around 390 nm with an associated lifetime near 1 ns, and the other (well known) emits at 340 nm with an associated lifetime of 2.7 ns. With both static and time-resolved fluorescences, the spectral and temporal effects of the excitation wavelength were studied between 285 and 340 nm. With these basic spectroscopic properties as a starting point, a fiber-optic chemical sensor (FOCS) was developed in order to measure 5-HT with a single-fiber configuration, nitrogen laser excitation, and fast digitizing techniques. Temporal effects including fluorescence of the optical fiber were studied and compared with measurements both directly in cuvette and through the fiber-optic sensor. Less than thirty seconds are required for each measurement. A detection limit of 5-HT is reached in the range of 5 μM. Our system, with an improved sensitivity, could therefore be a possible and convenient “tool” for in vivo determination of 5-HT.

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