Photoregulation of Biological Activity by Photochromic Reagents, IV. A Model for Diurnal Variation of Enzymic Activity

Bieth, Joseph G.; Wassermann, Norbert H.; Vratsanos, Spyros M.; Erlanger, Bernard F.

doi:10.1073/pnas.66.3.850

Cited by 54 publications

(25 citation statements)

References 5 publications

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“…Plasma cholinesterase activities are known to vary seasonally (Hill and Murray 1987) and this variation could be triggered by sunlight stimulation (Bieth et al 1970;Silver 1974). In our study, AChE activity was lowest and BuChE was highest in autumn 2003, when body condition index was very high.…”

Section: Effects Of Sex and Age-morphological And Haematological Paramentioning

confidence: 99%

Variation of adult Great Tit Parus major body condition and blood parameters in relation to sex, age, year and season

et al. 2009

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In recent years, an increasing number of studies have focused on the ranges of variation of health related biochemical and haematological parameters in wildlife, but information is still scarce for enzymatic activities which can be extremely important in detecting potential responses to environmental change. In a Great Tit (Parus major) population, we describe the variation in relation to age, sex, season and year of: (1) morphological: body condition index, fat and muscle, (2) haematological: hematocrit, haemoglobin, white blood cell count and heterophil/lymphocyte ratio, and (3) biochemical parameters: plasma protein and activities of plasma cholinesterases (acetylcholinesterase and butyrylcholinesterase) activity and red blood cell glutathione peroxidase. Sex had significant effects on all morphological parameters except fat. Age significantly affected cholinesterase activities, H/L ratio and haemoglobin, and there was a significant interaction between sex and age affecting hematocrit. There were significant interactions of year and season affecting almost all parameters studied-body condition index, fat, protein, acetyl and butyrylcholinesterase activities, glutathione peroxidase activity and haemoglobin. This study indicates that these parameters are largely influenced by year and seasonal effects, besides the individual's intrinsic variation. Therefore, when evaluating experimental or environmental change effects, appropriate controls should be used.

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Section: Effects Of Sex and Age-morphological And Haematological Paramentioning

confidence: 99%

Variation of adult Great Tit Parus major body condition and blood parameters in relation to sex, age, year and season

et al. 2009

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“…In these systems, photochromic azo derivatives were used as effector molecules to regulate the activities of chymotrypsin (1) and acetylcholinesterase (2,3) and to photoregulate the potential of the excitable membrane of the monocellular electroplax preparation (4). Photoregulation was achieved by exploiting differences between the biochemical activities of the cis and trans isomers of the photochromic compounds, the relative concentrations of which were influenced by the wavelength of light to which the solution was exposed [or light vs. darkness, in one case (3) ].…”

mentioning

confidence: 99%

Photochromic Activators of the Acetylcholine Receptor

Bartels

Wassermann

Erlanger

1971

Proc. Natl. Acad. Sci. U.S.A.

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203

179

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Two photochromic activators of the electrogenic membrane of the electroplax of Electrophorus electricus are described. monium)methyljazobenzene dibromide (Bis-Q), one of the most potent ever reported, is active at concentrations of less than 10-7 M. Its cis isomer, which is obtained from the trans by exposure to light of 330 nm, is practically devoid of activity. Photoregulation of the potential of the membrane takes place in the presence of Bis-Q, presumably because of the conversion of the active trans isomer to the inactive cis isomer in the single-cell electroplax system.The second activator, 3-(a-bromomethyl)-3'-[a-(trimethylammonium)methyllazobenzene bromide (QBr) can be covalently attached to the electroplax membrane after reduction of the membrane with dithiothreitol. Activation of the membrane is induced by the covalently linked reagent. Its cis isomer, obtained from the trans by exposure to light of 330 nm, is, like cis-Bis-Q, of very low activity. Both isomers of Bis-Q are equally active as inhibitors of acetylcholinesterase, 50% inhibition occurring at a concentration of 10-5 M. The possibility of using trans-Bis-Q and trans-QBr to characterize and isolate the receptor protein is discussed.Systems in which photoregulation could be studied at the molecular level were described in previous papers. In these systems, photochromic azo derivatives were used as effector molecules to regulate the activities of chymotrypsin (1) and acetylcholinesterase (2, 3) and to photoregulate the potential of the excitable membrane of the monocellular electroplax preparation (4). Photoregulation was achieved by exploiting differences between the biochemical activities of the cis and trans isomers of the photochromic compounds, the relative concentrations of which were influenced by the wavelength of light to which the solution was exposed [or light vs. darkness, in one case (3) ].Light-induced changes in potential of the electroplax membrane may be considered as a Mtodel for the process of vision, in which the cis to trans isomerization of retinal is the first step in the initiation of a neural impulse. In the latter case, however, as well as in the phytochrome system of plants (5), the photochromic substances are located intracellularly, making for a highly efficient process. It thus appeared of interest to prepare a light-sensitive ligand that would form a covalent bond with the receptor protein of the electroplax. A compound with the desired properties was prepared: 3-(a-bromomethyl)-3'-[a-(trimethylammonium)methyl]azobenzene (QBr). Also synthesized was the closely related 3,3'-bis[a-(trimethylammonium)methyl]azobenzene (Bis-Q). the trans isomer of which was found to be a potent receptor activator, one of the most potent thus far described.The high affinity and specificity of Bis-Q may make it a useful reagent for the characterization, isolation, and purification of the receptor protein. Some experiments with the two azo compounds are presented in this paper. METHODSPreparation of 3,3'-bis(a-bromomethyl)azobenz...

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“…"Levels of acetylcholinesterase activity can be made to vary in response to the presence or absence of sunlight in a system that can be considered as a model for photoperiodic processes found in nature" [8].…”

Section: Resultsmentioning

confidence: 99%

The Unexpected Bioenergetic Function of Neuromelanin. Implications in the Biology of Learning and Memory

Herrera¹,

Arias²

2017

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Progressive Recent Memory loss is the main complaint in Alzheimer's disease patients. There is not a simple or congruous explanation yet due to highly complex mechanisms by which the Central Nervous System store and organize experiences every day, developed along 4 billion years of evolution; thereby learning and memory are poorly understood biological processes. The finding of the unsuspected intrinsic property of melanin to transforms light into chemical energy through water dissociation, as chlorophyll in plants; opens a new and wider horizon in the form in which the CNS generate and distribute chemical energy transporting it through molecular hydrogen produced by substantia nigra of mesencephalon and other pigmented structures. The mechanisms by which human modifies their behavior through learning and memory remain a mystery despite several decades of research. However, the unexpected role of melanin molecule bioenergetics of first order, very above the chlorophyll and glucose, indicates that the study of the fascinating processes involved in learning and memory several levels, needs to be started with the study of the generation and distribution of energy neuro-melanin-releasing to all the brain. In this article, we explain succinctly, the way hydrogen molecular (H 2 )-gas-, from the dissociation of water by the neuro melanin, moves from its source and permeates easily through the different structures of the Central Nervous System, as well as be the smaller atom, does not combine with water, moving through it in accordance with the laws of the simple diffusion. Molecular hydrogen is the main carrier of energy that nature uses in the entire universe, so that, once the neuro melanin separates it from the water, this displaces transporting its precious cargo of energy and its remarkable antioxidant capacity capable of reduce oxygen and form water.

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Photoregulation of Biological Activity by Photochromic Reagents, IV. A Model for Diurnal Variation of Enzymic Activity

Cited by 54 publications

References 5 publications

Variation of adult Great Tit Parus major body condition and blood parameters in relation to sex, age, year and season

Variation of adult Great Tit Parus major body condition and blood parameters in relation to sex, age, year and season

Photochromic Activators of the Acetylcholine Receptor

The Unexpected Bioenergetic Function of Neuromelanin. Implications in the Biology of Learning and Memory

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