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1.
Molecules ; 26(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34443607

RESUMO

Cellular conformation of reduced pyridine nucleotides NADH and NADPH sensed using autofluorescence spectroscopy is presented as a real-time metabolic indicator under pressurized conditions. The approach provides information on the role of pressure in energy metabolism and antioxidant defense with applications in agriculture and food technologies. Here, we use spectral phasor analysis on UV-excited autofluorescence from Saccharomyces cerevisiae (baker's yeast) to assess the involvement of one or multiple NADH- or NADPH-linked pathways based on the presence of two-component spectral behavior during a metabolic response. To demonstrate metabolic monitoring under pressure, we first present the autofluorescence response to cyanide (a respiratory inhibitor) at 32 MPa. Although ambient and high-pressure responses remain similar, pressure itself also induces a response that is consistent with a change in cellular redox state and ROS production. Next, as an example of an autofluorescence response altered by pressurization, we investigate the response to ethanol at ambient, 12 MPa, and 30 MPa pressure. Ethanol (another respiratory inhibitor) and cyanide induce similar responses at ambient pressure. The onset of non-two-component spectral behavior upon pressurization suggests a change in the mechanism of ethanol action. Overall, results point to new avenues of investigation in piezophysiology by providing a way of visualizing metabolism and mitochondrial function under pressurized conditions.


Assuntos
NADP/química , NADP/metabolismo , NAD/química , NAD/metabolismo , Pressão , Fluorescência , Conformação Molecular
2.
Spectrochim Acta A Mol Biomol Spectrosc ; 186: 105-111, 2017 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-28646682

RESUMO

Phasor analysis on fluorescence signals is a sensitive approach for analyzing multicomponent systems. Initially developed for time-resolved measurements, a spectral version has been used for the rapid identification of regions during the spectral imaging of biological systems. Here we show that quantitative information regarding conformation can be obtained from phasor analysis of fluorescence spectrum shape. Methanol denaturation of NADH and NADH binding to various dehydrogenase proteins are used as model reactions. Thermodynamic constants are calculated and compared with previous studies based on more direct measures of conformation. Next, the quantitative monitoring of UV-excited autofluorescence spectrum shape during chemically-induced metabolic transitions is presented and discussed in terms of NADH-utilizing pathways. Results show how phasor analysis is useful in assessing two-state behavior, and in interpreting autofluorescence as emission from an ensemble of cellular NADH forms.


Assuntos
NAD , Espectrometria de Fluorescência/métodos , Animais , Metanol , Conformação Molecular , NAD/análise , NAD/química , NAD/metabolismo , Oxirredutases/química , Oxirredutases/metabolismo , Ligação Proteica , Desnaturação Proteica , Coelhos , Suínos , Termodinâmica
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