Coumarins in <i>Phormium</i> (New Zealand Flax) Fibers: Their Role in Fluorescence and Photodegradation

Smith, Gerald J.; Tang, Ying; Dyer, Jolon M.; Scheele, Sue

doi:10.1111/j.1751-1097.2010.00827.x

Cited by 5 publications

(1 citation statement)

References 35 publications

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“…According to the Rehm–Weller equation,7 the rate of the PET reaction from coumarin to DNB is governed by the energy of the excited state species (Δ G 00 ), the ground state oxidation potential of the coumarin donor ( E

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), the reduction potential of the DNB acceptor ( E A / A ‐), and the coulombic attraction energy ( E coul ). On the basis of the experimental data for the excited state energy (Δ G 00 =2.93 eV) and the available data for the oxidation potential of 7‐hydroxycoumarin12b ( E

_{italicD^{+} / italicD}

=0.67 V vs. SCE) and for the reduction potential of DNB,13 ( E A / A ‐=−0.88 V vs. SCE), the Gibbs energy (Δ G ) for the electron transfer in a polar environment7 ( E coul =0.03 eV) was found to be approximately −1.35 eV. This value was sufficiently negative for operating the diffusion‐controlled electron‐transfer process at ambient temperature.…”

Section: Fluorescence Quantum Yields Of the Synthesized Probes In Bufmentioning

confidence: 99%

Fluorogenic Protein Labeling through Photoinduced Electron Transfer‐Based BL‐Tag Technology

Sadhu

Mizukami

Lanam

et al. 2011

Chemistry An Asian Journal

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In recent years, protein labeling has been routinely performed with various fluorescent markers. [1] The labeling of proteins allows monitoring of the specific location, movement, and interaction of proteins with other intracellular components using fluorescence microscopy. [2] For several decades, the labeling strategy mostly dealt with green fluorescent protein (GFP) and its variants. In order to overcome the unaltered fluorescent property and uncontrolled expression time of GFP, small molecular probe-based labeling approaches for live-cell imaging methods have been developed. [3] However, most of the reported small-molecule labeling probes do not show different fluorescence properties for the labeled and unlabeled states. Fluorescein-based arsenical hairpin binder (FlAsH) and resorufin-based arsenical hairpin binder (ReAsH) are the pioneer techniques for fluorogenic protein labeling with small molecular probes. [4] In our earlier studies, we developed a site-specific protein labeling technique that employs a genetically modified blactamase (BL-tag). [5] Mutation at a specific position in TEM-1 (class A b-lactamases) provides turn-on fluorogenic biosensors involving a b-lactam ring. The reaction of wildtype TEM-1 (WT TEM) with the b-lactam moiety involves acylation and deacylation steps. [6] We have utilized the BLtag protein for covalent attachment with a substrate. Despite the similar molecular weights of the BL-tag and GFP, fluorogenicity can be introduced only through the BL-tag technology.We have developed a fluorogenic mechanism based on aggregation-elimination processes for highly selective protein labeling with a fluorophore of desired color using the BLtag technology. We have also shown a broad applicability of dinitrobenzene (DNB) as a quencher. [5c,d] However, the limitation of the technology is a slow fluorogenic response of the synthesized probes such as CCDNB, which carries a coumarin fluorophore moiety, a cephalosporin moiety, and DNB (Figure 1). The necessary incubation time for a cell imaging experiment using CCDNB was 60 minutes. To reduce the incubation time for the imaging experiments, we aimed at developing more sophisticated probes that possess the DNB quencher. Herein, we report two newly designed probes with shorter linkers compared to those of CCDNB. In addition, we modified slightly the quencher in one probe. The probe with the modified quencher showed a comparatively fast fluorogenicity in vitro and in live-cell imaging studies. Fluorescence lifetime measurements indicated a different quenching mechanism for the most active probe. A detailed analysis of this new fluorogenic mechanism revealed a photoinduced electron transfer (PET) process [7] from the fluorophore donor to the quencher acceptor.The two new probes CC2 DNB and CC3 DNB that have a comparatively short or no linker between the b-lactam and quencher, respectively, are depicted in Figure 1. 2-(2-Aminoethoxy)ethanamine was used as the linker between the cephalosporin part and the DNB quencher in CC2 DNB. A coumarin deri...

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_{italicD^{+} / italicD}

_{italicD^{+} / italicD}

Section: Fluorescence Quantum Yields Of the Synthesized Probes In Bufmentioning

confidence: 99%

Fluorogenic Protein Labeling through Photoinduced Electron Transfer‐Based BL‐Tag Technology

Sadhu

Mizukami

Lanam

et al. 2011

Chemistry An Asian Journal

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Conservation Theory and Practice: Materials, Values, and People in Heritage Conservation

Sully¹

2015

The International Handbooks of Museum Studies

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Conservation, as an emerging discipline, is mutually constituted with the heritage institutions in which it is practiced. Professional conservators have been amending the focus of their work, from attending to the material preservation of heritage spaces, places, and objects, toward the values that people have for their cultural heritage. This chapter describes an alternative conservation product, which is entangled within the multiple interactions between objects and people developed during the conservation event. This reflects a shift in focus from the materials from which conservation objects are composed, to the aspirations of the people who are affected by the conservation of their heritage. This challenges conventional heritage conservation practice, by privileging a community's cultural systems over universalized concepts of heritage. As a result, conservation practice requires principles, policies, and guidelines that help conservators to engage people in decision‐making about their heritage. New frameworks for understanding conservation practice enable creative and diverse solutions within heritage conservation. This is described in this chapter in terms of materials‐, values‐, and peoples‐based approach to conservation. This allows heritage conservation to address the social issues of the present and engage the future, rather than merely seeking to fix the past. In so doing, it validates conservation responses that seek to incorporate the multiple ways that people care for and use their own cultural heritage.

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Fluorescence and photodegradation of Xuan paper: The photostability of traditional Chinese handmade paper

Tang

Smith

2013

Journal of Cultural Heritage

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Coumarins in Phormium (New Zealand Flax) Fibers: Their Role in Fluorescence and Photodegradation

Cited by 5 publications

References 35 publications

Fluorogenic Protein Labeling through Photoinduced Electron Transfer‐Based BL‐Tag Technology

Fluorogenic Protein Labeling through Photoinduced Electron Transfer‐Based BL‐Tag Technology

Conservation Theory and Practice: Materials, Values, and People in Heritage Conservation

Fluorescence and photodegradation of Xuan paper: The photostability of traditional Chinese handmade paper

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