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Clarke KT, Hopkins SL, Krosch MN, Cresswell SL, Gee WJ. Showcasing water-based delivery of an amino acid targeting fingermark developer in a hydrogel. Forensic Sci Int 2024; 360:112045. [PMID: 38703405 DOI: 10.1016/j.forsciint.2024.112045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/13/2024] [Accepted: 04/15/2024] [Indexed: 05/06/2024]
Abstract
Most recommended methods for visualising fingermarks on paper rely on chemical developers that target and react with amino acids. Traditionally, these developers are sprayed onto paper substrates in solutions of per- and polyfluoroalkyl substances (PFAS), but now those same PFAS chemicals are undergoing phaseout or phasedown, which threatens to undermine forensic capabilities. This situation provides an opportunity to pivot towards greener approaches to fingermark visualisation. The ideal methodology would be a water-based treatment, as these provide superior safety for practitioners, combined with environmental sustainability. A major hurdle to implementing a water-based fingermark developer targeting amino acids is that water, as a universal solvent, can dissolve the eccrine components in fingermarks, as well as any optical or luminescent dyes that are created, causing the ridge detail to run or dissolve. This work circumvents this problem by delivering the amino acid developer alloxan in a hydrogel, which enables sharp fingermark ridge details to be observed despite it being a water-based treatment. Alloxan dissolved in a viscous hydrogel is shown here to react with the amino acids in fingerprint residues to form the coloured dye murexide, supported by optimisation and characterisation studies.
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Affiliation(s)
- Kristen T Clarke
- Queensland Micro, and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia; School of Environment and Science, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia
| | - Scarlet L Hopkins
- School of Environment and Science, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia
| | - Matthew N Krosch
- Quality Management Section, Forensic Services Group, Queensland Police Service, Brisbane, QLD, 4000
| | - Sarah L Cresswell
- School of Environment and Science, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia
| | - William J Gee
- Queensland Micro, and Nanotechnology Centre, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia; School of Environment and Science, Griffith University, 170 Kessels Road, Brisbane, QLD 4111, Australia.
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2
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Eprintsev AT, Fedorin DN, Cherkasskikh MV, Igamberdiev AU. Expression of succinate dehydrogenase and fumarase genes in maize leaves is mediated by cryptochrome. JOURNAL OF PLANT PHYSIOLOGY 2018; 221:81-84. [PMID: 29268085 DOI: 10.1016/j.jplph.2017.12.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/27/2017] [Accepted: 12/02/2017] [Indexed: 06/07/2023]
Abstract
Blue light inhibits succinate dehydrogenase and fumarase enzyme activity and gene expression in green leaves of maize (Zea mays L.). Irradiation of maize plants by blue light resulted in the transient decrease of transcripts of genes Sdh1-2 and Sdh2-3 encoding correspondingly the flavoprotein and iron-sulfur protein subunits of succinate dehydrogenase, and of Fum1 encoding the mitochondrial form of fumarase. The blue light effect was probably mediated by transcription factors COP1 and HY5, with the expression of the latter increased upon blue light treatment. This was accompanied by a decrease in the expression of COP1, presumably involved in proteasome degradation of HY5. It was also demonstrated that calcium ions do not participate in this process.
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Affiliation(s)
- Alexander T Eprintsev
- Department of Biochemistry and Cell Physiology, Voronezh State University, 394006 Voronezh, Russia
| | - Dmitry N Fedorin
- Department of Biochemistry and Cell Physiology, Voronezh State University, 394006 Voronezh, Russia
| | - Mikhail V Cherkasskikh
- Department of Biochemistry and Cell Physiology, Voronezh State University, 394006 Voronezh, Russia
| | - Abir U Igamberdiev
- Department of Biology, Memorial University of Newfoundland,St. John's, NL A1 B 3X9, Canada.
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3
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Eprintsev AT, Fedorin DN, Igamberdiev AU. Ca²⁺ is involved in phytochrome A-dependent regulation of the succinate dehydrogenase gene sdh1-2 in Arabidopsis. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:1349-1352. [PMID: 23711731 DOI: 10.1016/j.jplph.2013.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 04/21/2013] [Accepted: 04/21/2013] [Indexed: 06/02/2023]
Abstract
The mechanism of transduction of the phytochrome signal regulating the expression of succinate dehydrogenase in Arabidopsis has been investigated. Using the phytochrome mutants of Arabidopsis, it is demonstrated that the inhibition of succinate dehydrogenase in the light may result from the phytochrome A-dependent modulation of Ca²⁺ amount in the nuclear fraction of leaves. This leads to the activation of expression of the gene pif3 encoding the phytochrome-interacting factor PIF3, which binds to the promoter of the gene sdh1-2 encoding the SDHA subunit of succinate dehydrogenase and suppresses its expression. It is concluded that Ca²⁺ ions are involved in the phytochrome A-mediated inhibition of succinate dehydrogenase activity in the light.
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Affiliation(s)
- Alexander T Eprintsev
- Department of Biochemistry and Cell Physiology, Voronezh State University, 394006 Voronezh, Russia
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Roux SJ, McEntire K, Slocum RD, Cedel TE, Hale CC. Phytochrome induces photoreversible calcium fluxes in a purified mitochondrial fraction from oats. Proc Natl Acad Sci U S A 2010; 78:283-7. [PMID: 16592951 PMCID: PMC319037 DOI: 10.1073/pnas.78.1.283] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Previous studies have indicated that phytochrome regulates Ca(2+) fluxes across the plasma membrane of plant cells. In this study we investigated whether phytochrome can also regulate such fluxes across mitochondrial membranes, using the Ca(2+)-sensitive dye murexide to monitor the uptake and release of Ca(2+) by mitochondria. The results showed that Ca(2+) fluxes in these organelles could be photoreversibly altered, red light diminishing the net uptake rate and far-red light restoring this rate to its dark control level. Treatment of the mitochondria with ruthenium red blocked their Ca(2+) uptake. In the presence of this inhibitor, red light induced a net efflux of Ca(2+) from the mitochondria, and subsequent far-red light reduced this efflux to nearly zero, the dark control level. Light-induced rate changes in Ca(2+) flux, both with and without the inhibitor, persisted for several minutes in the dark and remained photoreversible through several irradiations for as long as 30 min. The purity of the mitochondrial preparation was judged to be about 80% by electron microscopic morphometry; most of the phytochrome present was localized on the mitochondria in the preparation by using immunocytochemical methods. Taken together with previous findings, the results suggest that red light activation of phytochrome would initiate an increase in the cytosolic Ca(2+) concentration. The results are integrated with the fact that calmodulin is a component of plant cell cytoplasms to construct a model postulating that phytochrome directs photomorphogenesis in part through its regulation of Ca(2+) and calmodulin-controlled enzyme activities.
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Affiliation(s)
- S J Roux
- Department of Botany and Cell Research Institute, The University of Texas at Austin, Austin, Texas 78712
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5
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Sherratt HS, Watmough NJ, Johnson MA, Turnbull DM. Methods for study of normal and abnormal skeletal muscle mitochondria. METHODS OF BIOCHEMICAL ANALYSIS 2006; 33:243-335. [PMID: 3282151 DOI: 10.1002/9780470110546.ch6] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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6
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Bazhenova EN, Deryabina YI, Eriksson O, Zvyagilskaya RA, Saris NE. Characterization of a high capacity calcium transport system in mitochondria of the yeast Endomyces magnusii. J Biol Chem 1998; 273:4372-7. [PMID: 9468487 DOI: 10.1074/jbc.273.8.4372] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Ca2+ transport system of Endomyces magnusii mitochondria has been shown previously to be activated by spermine. Here we report it to be regulated also by low, physiological ADP concentrations, by the intramitochondrial NADH/NAD+ ratio, and by Ca2+ ions. The combination of all these physiological modulators induced high initial rates of Ca2+ uptake and high Ca2+-buffering capacity of yeast mitochondria, enabling them to lower the medium [Ca2+] to approximately 0.2 microM. The mechanisms of stimulation by these agents are discussed.
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Affiliation(s)
- E N Bazhenova
- Laboratory of Biological Oxidation, Bach Institute of Biochemistry, Russian Academy of Sciences, 117071 Moscow, Russia
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7
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Westergaard N, Banke T, Wahl P, Sonnewald U, Schousboe A. Citrate modulates the regulation by Zn2+ of N-methyl-D-aspartate receptor-mediated channel current and neurotransmitter release. Proc Natl Acad Sci U S A 1995; 92:3367-70. [PMID: 7536931 PMCID: PMC42167 DOI: 10.1073/pnas.92.8.3367] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The effect of the two metal-ion chelators EDTA and citrate on the action of N-methyl-D-aspartate (NMDA) receptors was investigated by use of cultured mouse cerebellar granule neurons and Xenopus oocytes, respectively, to monitor either NMDA-evoked transmitter release or membrane currents. Transmitter release from the glutamatergic neurons was determined by superfusion of the cells after preloading with the glutamate analogue D-[3H]aspartate. The oocytes were injected with mRNA isolated from mouse cerebellum and, after incubation to allow translation to occur, currents mediated by NMDA were recorded electrophysiologically by voltage clamp at a holding potential of -80 mV. It was found that citrate as well as EDTA could attenuate the inhibitory action of Zn2+ on NMDA receptor-mediated transmitter release from the neurons and membrane currents in the oocytes. These effects were specifically related to the NMDA receptor, since the NMDA receptor antagonist MK-801 abolished the action and no effects of Zn2+ and its chelators were observed when kainate was used to selectively activate non-NMDA receptors. Since it was additionally demonstrated that citrate (and EDTA) preferentially chelated Zn2+ rather than Ca2+, the present findings strongly suggest that endogenous citrate released specifically from astrocytes into the extracellular space in the brain may function as a modulator of NMDA receptor activity. This is yet another example of astrocytic influence on neuronal activity.
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Affiliation(s)
- N Westergaard
- Department of Biological Sciences, Royal Danish School of Pharmacy, Copenhagen
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8
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Inhibition of calcium phosphate precipitation by bile salts: a test of the Ca(2+)-buffering hypothesis. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)41217-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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9
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Votyakova TV, Bazhenova EN, Zvjagilskaya RA. Yeast mitochondrial calcium uptake: regulation by polyamines and magnesium ions. J Bioenerg Biomembr 1993; 25:569-74. [PMID: 8132496 DOI: 10.1007/bf01108413] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Spermine, spermidine, and magnesium ions modulate the kinetic parameters of the Ca2+ transport system of Endomyces magnusii mitochondria. Mg2+ at concentrations up to 5 mM partially inhibits Ca2+ transport with a half-maximal inhibiting concentration of approximately 0.5 mM. In the presence of 2 mM MgCl2, the S0.5 value of the Ca2+ transport system increases from 220 to 490 microM, which indicates decreased affinity for the system. Spermine and spermidine exert an activating effect, having half-maximal concentrations of 12 and 50 microM, respectively. In the case of spermine, the S0.5 value falls to 50-65 microM, which implies an increase in the transport system affinity for Ca2+. Both Mg2+ and spermine cause a decrease of the Hill coefficient, giving evidence for a smaller degree of cooperativity. Spermine and spermidine enable yeast mitochondria to remove Ca2+ from the media completely. In contrast, Mg2+ lowers the mitochondrial buffer capacity. When both Mg2+ and spermine are present in the medium, their effects on the S0.5 value and the free extramitochondrial Ca2+ concentration are additive. The ability of spermine and Mg2+ to regulate yeast mitochondrial Ca2+ transport is discussed.
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Affiliation(s)
- T V Votyakova
- A. N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow
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10
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Bruckner-Lea C, Durney CH, Janata J, Rappaport C, Kaminski M. Calcium binding to metallochromic dyes and calmodulin in the presence of combined, AC-DC magnetic fields. Bioelectromagnetics 1992; 13:147-62. [PMID: 1590813 DOI: 10.1002/bem.2250130208] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The possibility that weak, ac and dc magnetic fields in combination may affect binding equilibria of calcium-ions (Ca2+) was investigated with two metallochromic dyes as calcium-binding molecules: murexide and arsenazo III. Calcium-dye equilibria were followed by measuring solution absorbances with a fiber-optic spectrophotometer. A Ca(2+)-arsenazo solution was also used indirectly to monitor the binding of Ca2+ to calmodulin. Parallel, ac and dc magnetic fields were applied to each preparation. The ac magnetic field was held constant during each of a series of experiments at a frequency in the range between 50 and 120 Hz (sine wave) or at 50 pps (square wave) and at an rms flux density in the range between 65 and 156 microT. The dc magnetic field was then varied from 0 to 299 microT at 1.3 microT increments. The magnetic fields did not measurably affect equilibria in the binding of metallochromic dyes or calmodulin to Ca2+.
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Affiliation(s)
- C Bruckner-Lea
- Electrical Engineering Department, University of Utah, Salt Lake City 84112
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11
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Requena J, Whittembury J, Scarpa A, Brinley JF, Mullins LJ. Intracellular ionized calcium changes in squid giant axons monitored by Fura-2 and aequorin. Ann N Y Acad Sci 1991; 639:112-25. [PMID: 1785835 DOI: 10.1111/j.1749-6632.1991.tb17295.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Squid giant axons were injected simultaneously with Ca indicators Fura-2 and aequorin. Fura-2 was calibrated in situ by measuring fluorescence at 510 nm upon UV excitation at 340 nm, 360 nm, and 380 nm with a time-sharing multiple wavelength spectrofluorimeter. Limiting values for dye fluorescence were obtained by allowing a massive load of Ca to enter the axon with the aid of procedures such as prolonged depolarization in the presence of CN (for saturation) and by sequestration of all Ca present in the axoplasm accomplished with injection of EGTA into the axon (for a zero-Ca signal). The average intracellular Ca concentration obtained with Fura-2 was 184 nM. The sensitivity of Fura-2 to intracellular Ca is at least as great as that of aequorin, thus permitting its use in the characterization of Ca homeostasis mechanisms such as Na-Ca exchange. It was found, however, that for voltage-clamp experiments requiring an internal current electrode, Fura-2 is not a convenient Ca probe because electrode reactions in the axoplasm denature the dye, thereby restricting its use in characterization of Ca movements associated with electrically induced changes in membrane potential. A comparison of aequorin luminescence with Fura-2 fluorescence demonstrated that light output by aequorin is linear with intracellular Ca concentrations up to values of 750 nM, changing to a square law relationship from 750 nM up to 10 microM Ca.
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Affiliation(s)
- J Requena
- Centro de Biociencias, Instituto Internacional de Estudios Avanzados (IDEA), Caracas, Venezuela
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12
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Abstract
Calcium binding to bile salt monomers and micelles is an important issue with respect to the possible (but rare) precipitation of calcium bile salts in the gallbladder. In the present work the binding of Ca2+ to six bile salts was measured in solutions containing 2 to 100 mM bile salts by means of a calcium-sensitive dye, murexide, which determines the ionic calcium concentration. In solutions containing bile salt at concentration higher than 20 mM most, if not all, of the bound Ca2+ is associated with micellar surfaces. The results were analyzed by employing a model which combines specific binding with electrostatic equations and accounts for the system being a closed one. The analysis of Ca2+ binding data considered explicitly the presence of Na+ ions and yielded intrinsic binding coefficients for Ca2+ and Na+ which were utilized to explain and predict binding results for various concentrations of Ca2+, Na+ and bile salts. The calculations indicate that in saline solutions most of the surface sites were bound by Na+, whereas less than 10% were bound by Ca2+ even in the presence of 8 mM Ca2+. The binding of Ca2+ to bile salt micelles increases with pH. An increase in temperature results in reduced binding affinity of Ca2+ to the bile salt micelles.
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Affiliation(s)
- E Baruch
- Dept. of Physiology and Pharmacology, Tel-Aviv University, Sackler School of Medicine, Israel
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13
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Chae Q, Park HJ, Hong SD. Loading of quin2 into the oat protoplast and measurement of cytosolic calcium ion concentration changes by phytochrome action. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1051:115-22. [PMID: 2310765 DOI: 10.1016/0167-4889(90)90182-d] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The loading of quin2 into oat protoplasts was carried out in an incubation medium (0.6 M sorbitol, 1 mM CaCl2, 5 mM Mes, 5 mM Tris, 0.05% BSA, 1 mM KCl, 1 mM MgSO4 (pH 6.8)), in which we found the best viability of the protoplast and the highest membrane permeability of quin2/AM, compared with the results obtained from any other incubation medium we had tried to use. 50 microns of quin2/AM was added in the suspension medium containing 5 x 10(5)/ml of oat protoplasts, and incubation at 4 degrees C was performed for 24 h. From atomic absorption data, we confirmed that quin2 loading was 1.78 mmol per liter of cells. Red-light (660 nm) irradiation for 5 min caused an increase of the cytosolic Ca2+ concentration from 30 to 193 nM. On the other hand, a subsequent irradiation with far-red light (730 nm) for 5 min decreased it by about 48 nM. Even when the extracellular Ca2+ was completely chelated with 1 mM EDTA, red light increased the cytosolic Ca2+ concentration by about 51 nM and far-red light decreased it to 3 nM. These results imply that the Pfr form of phytochrome functions not only in the process of influx of Ca2+, but also in the mobilization process of Ca2+ from the intracellular Ca2+ pools. The fact that the Pr form of phytochrome lowers the cytosolic Ca2+ concentration is also presented in this report.
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Affiliation(s)
- Q Chae
- Department of Biochemistry, Chungbuk National University, Cheongju, Korea
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14
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Votyakova TV, Bazhenova EN, Zvjagilskaya RA. Polyamines improve Ca2+ transport system of the yeast mitochondria. FEBS Lett 1990; 261:139-41. [PMID: 2307229 DOI: 10.1016/0014-5793(90)80655-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Spermine at concentrations of 12-100 microM considerably activates the Ca2+ transport system of the Endomyces magnusii yeast mitochondria. As a result, in the presence of spermine the mitochondria are able to decrease extramitochondrial Ca2+ to the physiological level. At Ca2+ concentrations up to 200 microM, spermine enhances the initial rate of Ca2+ uptake (a half-maximal effect at 12 microM spermine). The Ca2+ concentrations required for half-maximal Ca2+ uptake rate to be achieved were 160 and 60 microM Ca2+ without and with spermine, respectively. Spermidine is shown to be less effective (a half-maximal effect at 50-100 microM spermidine). The polyamines do not change the parameters of energy coupling of mitochondria. The data obtained enabled the yeast mitochondria to be considered to take part in regulation of cytoplasmic and matrix Ca2+.
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Affiliation(s)
- T V Votyakova
- A.N. Bach Institute of Biochemistry, Academy of Sciences of the USSR, Moscow
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15
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Spectrophotometric study of the complexation reactions between alkaline earth cations and murexide in some non-aqueous solutions. Polyhedron 1988. [DOI: 10.1016/s0277-5387(00)81216-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Shimoni Y, Ginsburg S. Negative inotropic effect of extracellular calcium buffering in cardiac muscle. THE AMERICAN JOURNAL OF PHYSIOLOGY 1987; 252:C248-52. [PMID: 3826337 DOI: 10.1152/ajpcell.1987.252.2.c248] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Heart muscle contracts more vigorously when calcium levels are raised. A transient depletion of calcium from restricted extracellular spaces occurs with each contraction. We decided to maintain the concentration of this ion at a constant level by using an external calcium buffering system. It was found that buffering calcium at a millimolar level (using citrate as a buffer) caused a decrease, rather than an increase in the strength of contraction. The mean reduction in peak tension was by 27% in guinea pig and by 50.5% in frog atrium. This finding is analyzed; its most plausible explanation is the hypothesis that the buffer dissipates a calcium inhomogeneity, consisting of a higher calcium concentration adjacent to the membrane. Alternative interpretations such as intracellular acidosis, were tested experimentally and ruled out.
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18
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Moreno SN, Docampo R. Reduction of the metallochromic indicators murexide and tetramethylmurexide to their free radical metabolites by cytoplasmic enzymes and reducing agents. Chem Biol Interact 1986; 57:17-25. [PMID: 3004749 DOI: 10.1016/0009-2797(86)90045-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Murexide underwent reduction by rat liver cytosolic fraction or a hypoxanthine-xanthine oxidase system to produce a free radical metabolite. Reduction of murexide by the freshly prepared cytosolic fraction depended upon the presence of ascorbic acid. N1-Methylnicotinamide, xanthine or hypoxanthine, in that order, could also serve as a source of reducing equivalents for the production of that free radical by the cytosolic fraction. Several thiol compounds (GSH, cysteine, and cysteamine), pyridine nucleotides (NADH, NADPH) and ascorbic acid were also effective in generating the murexide-derived free radical. Tetramethyl murexide was also reduced to its free radical derivative by a hypoxanthine-xanthine oxidase system.
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Bernard PA, Cockrell RS. Calcium transport by rat brain mitochondria and oxidation of 2-oxoglutarate. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1984; 766:549-53. [PMID: 6548153 DOI: 10.1016/0005-2728(84)90113-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Contrary to previous reports brain mitochondria have a substantial capacity for net Ca2+ uptake (approx. 1.2 mueq. Ca2+ per mg protein) providing succinate is the oxidizable substrate. ATP stimulates calcium uptake (to 1.8 mueq. per mg protein), but is not required. The accumulation of Ca2+ with NAD-linked substrates is, however, significantly less. With 2-oxoglutarate, very limited Ca2+ uptake occurs before respiration is inhibited. At low concentrations (10 microM), Ca2+ stimulates the 2-oxoglutarate dehydrogenase activity of detergent solubilized mitochondria. Millimolar [Ca2+] is required for inhibition. Therefore, Ca2+ inhibition of 2-oxoglutarate oxidation can explain the low maximum uptake with this substrate, but probably not by directly effecting the dehydrogenase. Hence, the oxidation of 2-oxoglutarate can be either enhanced or suppressed depending upon the net Ca2+ accumulated by brain mitochondria.
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20
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Docampo R, Moreno SN, Mason RP. Generation of free radical metabolites and superoxide anion by the calcium indicators arsenazo III, antipyrylazo III, and murexide in rat liver microsomes. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)43751-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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21
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Ginsburg S, Rahamimoff R. Is extracellular calcium buffering involved in regulation of transmitter release at the neuromuscular junction? Nature 1983; 306:62-4. [PMID: 6314147 DOI: 10.1038/306062a0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
During synaptic activity at the neuromuscular junction, sodium, potassium and calcium ions flow through both the postsynaptic and presynaptic membrane. These ionic fluxes can cause changes in the local extracellular concentration in the synaptic gap: a decrease in the concentration of the inwardly flowing ions (sodium and calcium) and an increase in the outwardly flowing potassium ions. To check whether depletion of calcium ions in the synaptic gap is involved in transmitter release, we have used calcium buffers to keep the extracellular calcium concentration almost constant. The expectation was that if depletion does occur, transmitter release will increase; if no depletion occurs, there will be no change in quantal release when the calcium concentration is the same in buffered and unbuffered bathing solutions. We report here that, surprisingly, perfusing the frog neuromuscular preparation with a calcium-buffered solution caused a decrease in transmitter release compared with that in an unbuffered solution with the same calcium concentration. This presumably indicates that the calcium level in the synaptic cleft is higher than that in the bulk extracellular medium. If such a mechanism operates physiologically, it may provide an energetically economical way to determine the level of evoked transmitter release and thus synaptic efficiency.
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22
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Lockau W, Pfeffer S. ATP-dependent calcium transport in membrane vesicles of the cyanobacterium, Anabaena variabilis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 1983. [DOI: 10.1016/0005-2736(83)90098-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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de Muñiz BR, Maresca BM, Tumilasci OR, Perec CJ. Effects of an experimental diet on parotid saliva and dental plaque pH in institutionalized children. Arch Oral Biol 1983; 28:575-81. [PMID: 6579891 DOI: 10.1016/0003-9969(83)90004-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Sixty-six children aged 6-12, permanent residents of a children's home, were placed on a diet during a 45-day experimental period to measure salivary flow-rate, pH of saliva and dental plaque, total concentrations of salivary proteins, inorganic phosphate, bicarbonate, calcium and amylase. The total caloric content, as well as the proportional nutrient and calorie distribution of the foods, were determined and compared with those of the previous habitual diet. After the experimental period, stimulated parotid salivary flow, increased by 40 per cent over the pre-experimental values. Total proteins of saliva and pH of both saliva and dental plaque increased significantly, whereas inorganic phosphate concentration decreased. Concentrations of bicarbonate, calcium and amylase did not differ from those found pre-experimentally. The findings appear to derive from lesser retention and increased hardness of the foods in the experimental diet.
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Cockrell RS. The influence of nupercaine on Ca2+ transport by rat liver and Ehrlich ascites cell mitochondria. FEBS Lett 1982; 144:279-82. [PMID: 7117542 DOI: 10.1016/0014-5793(82)80654-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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25
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Scarpa A, Dubyak G. Measurements of intracellular free Ca++. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1982; 151:443-59. [PMID: 7180662 DOI: 10.1007/978-1-4684-4259-5_50] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Heffner LJ, Storey BT. The role of calcium in maintaining motility in mouse spermatozoa. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1981; 218:427-34. [PMID: 7338726 DOI: 10.1002/jez.1402180314] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Maintenance of mouse sperm motility requires exogenous Ca+2 in most, but not all, samples of epididymal spermatozoa. In these samples, the loss of motility with time is the same in Tris/NaCl buffer containing 1.7 mM Ca+2 (medium TNC) as it is in complete culture medium used for in vitro fertilization (medium CM) over the first 2 hours; spermatozoa in medium TNC lose motility at more rapid rate thereafter. The cation specificity for maintenance of motility is unusual in that both Sr+2 and Mg+2 substitute for Ca+2, with Mg+2 being the more effective. In the absence of Ca+2, these samples of mouse epididymal spermatozoa in Tris/NaCl buffer (medium TN) lose motility in about 30 minutes. If Ca+2 is added after incubation in TN for 15 minutes, motility is maintained as well as it is in medium TNC. If Ca+2 is added at 30 minutes, motility is partially restored. But if Ca+2 is added after 60 minutes, there is no restoration of motility. Spermatozoa suspended in medium TNC lose motility rapidly on addition of EGTA in excess of the Ca+2 present. Attempts to show uptake of Ca+2 by spectrophotometric assay, by effects of Ca+2 on oxidative metabolism, and by electron probe X-ray microanalysis were unsuccessful; motility is not maintained by entry of Ca+2 into the cells. Our results are consistent with a Ca+2 site on the plasma membrane and suggest that these sites function as oligomers of ordered subunits whose structure requires Ca+2. In the absence of Ca+2, the ability to form the oligomer is lost with time, possibly due to an irreversible conformational change.
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Taylor J. Sarcoplasmic reticulum ATPase catalyzes hydrolysis of adenyl-5'-yl imidodiphosphate. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68692-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Takisawa H, Makinose M. Occluded bound calcium on the phosphorylated sarcoplasmic transport ATPase. Nature 1981; 290:271-3. [PMID: 6451810 DOI: 10.1038/290271a0] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The Ca2+ + Mg2+-activated ATPase of the sarcoplasmic reticulum is responsible for the active Ca2+ transport of this membrane system, the key feature of which is the formation of an energy-rich phosphorylated transport enzyme (EP) and its conversion. To understand the Ca2+-transport mechanism, it is essential to clarify the behaviour of this intermediate in relation to such ligands as ATP, ADP, Mg2+ and, particularly, Ca2+. Recent kinetic studies on the phosphate turnover of this system suggested a relatively slow rate of Ca2+ dissociation from the phosphorylated enzyme, which possibly indicated Ca2+ binding in some occluded form with the intermediate. Here we report direct measurements of the binding and release of Ca2+ during phosphorylation of the sarcoplasmic transport enzyme. The results indicate an occlusion of the Ca2+ binding, accompanying an initial configurational change of the enzyme induced by the energy-rich phosphoryl transfer.
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Abstract
Studies were undertaken to determine the mechanisms leading to altered mitochondrial function in ischemic myocardium. A new procedure has been developed to routinely isolate 60-70% of the total mitochondrial protein from heart tissue. After 1 hour of ischemia, mitochondria exhibit decreases of more than 50% in phosphorylating respiration for both NADH- and succinate-linked substrates compared to controls. However, no significant decreases in the efficiency of mitochondrial ATP synthesis (ADP:0) or ATPase activity are observed. Rates of substrate-driven Ca2+ uptake exhibit decreases greater than that seen with phosphorylating respiration with incomplete uptake and premature release of Ca2+. Spectrophotometric measurements in ischemic heart reveal rapid oxidation or loss of mitochondrial NADH with marked "swelling" of the inner membrane compartment; both changes parallel the loss of Ca2+. Significant losses in intramitochondrial adenine nucleotides also are found. Mitochondrial retention of accumulated Ca2+ can be restored by addition of small amounts of exogenous adenine nucleotides (ATP or ADP) with concomitant attenuation of both NADH oxidation and "swelling." The data indicate that, following 1 hour of ischemia, the efficiency of mitochondrial ATP production is still relatively intact whereas both electron transport chain activity and calcium transport are severely compromised. These decreases appear to be related to selective membrane damage in the mitochondrial inner membrane.
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Bauman VK, Andrushaite RE, Berzin' NI, Valinietse MY, Val'dman AR. Direct stimulating action of blood serum and of vitamin D3 and its hydroxy-analogs on calcium transport in the chicken small intestine in vitro. Bull Exp Biol Med 1980. [DOI: 10.1007/bf00830444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abercrombie RF, Sjodin RA. Calcium efflux from Myxicola giant axons: effects of extracellular calcium and intracellular EGTA. J Physiol 1980; 306:175-91. [PMID: 6780685 PMCID: PMC1282999 DOI: 10.1113/jphysiol.1980.sp013390] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
1. (45)Ca efflux was examined in Myxicola giant axons injected with (45)CaCl(2) or various concentrations of (45)Ca/EGTA buffers. In axons injected with (45)CaCl(2), the Ca(o)-dependent Ca efflux in 1 mM-Ca(o) was about half that in 10 mM-Ca(o).2. Axons injected with (45)Ca/EGTA buffers consistently showed two types of results: in one type (B type), K((1/2)) for Ca(o) activation was less than 1 mM-Ca(o). In the other type of result (A type), there was an additional Ca activation of Ca efflux. This additional efflux exhibited a linear dependence on Ca(o) when the Ca(o) values ranged between 1 mM-Ca(o) and 10 mM-Ca(o).3. The B-type result remained unchanged when the injected Ca/EGTA concentrations were varied. The A type result, however, changed as a function of Ca/EGTA(i) in the following way: (a) at a constant ratio of Ca/EGTA(i) = 8/10, the megnitude of the linear component of the Ca(o)-activated Ca efflux was reduced by increasing the intracellular concentration of (Ca/EGTA) buffer; and (b) at a ratio Ca/EGTA = 1/10, the linear component of the Ca(o)-activated Ca efflux appeared to acquire a slower time response to changes in Ca(o).4. Na(o) acts synergistically with Ca(o) to produce the linear component of the Ca-activated Ca efflux seen in the A type result.5. With axons containing (45)Ca/EGTA buffers (total EGTA(i) = 1 mM), changing the Ca/EGTA ratio by repetitive injections of CaCl(2) did not increase (45)Ca efflux by as great an amount as would be predicted if Ca(i) (2+) were controlled by the EGTA buffer alone.6. Ca(i) (2+) (measured by arsenazo III absorbance) is influenced by Ca(o) irrespective of the presence of 1 mM-EGTA buffer inside the axon. There was a variability in the sensitivity of Ca(i) to Ca(o) that resembled the variability found in (45)Ca efflux measurements.7. (45)Ca influx is not affected by the concentration of Ca/EGTA buffer injected into the cell and appears to be only slightly, if at all, affected by increasing ionized Ca(i) (2+) from 0.016 to 0.56 muM in the injection medium.8. These results are consistent with the interpretation that the Ca efflux system of the Myxicola giant axon, or something controlling it, can exist in more than one state. One of these states, which exhibited a large Ca(o)-dependent Ca efflux, may represent axons in which Ca(i) is poorly controlled by the natural endogenous Ca buffers.
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Wan KK, Boegman RJ. Calcium uptake by muscle sarcoplasmic reticulum following neural application of batrachotoxin or tetrodotoxin. FEBS Lett 1980; 112:163-7. [PMID: 7371853 DOI: 10.1016/0014-5793(80)80171-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Abstract
Given the existence of a difference in electrical potential between the interior of a nerve cell and the media surrounding it, where the cytoplasm is some 70 mV negative (Hodgkin, 1958), it must be expected that any positively charged ion to which the cell membrane is permeable is more concentrated in the cell interior. For monovalent cations such as Na and divalent cations such as Ca and Mg this is not the case in the majority of the cells such as the squid giant axon. In other words, nerve cells maintain a lower intracellular concentration of these ions, as compared with their concentration in the extracellular fluid. For Mg, Ca and Na ions, this lower internal concentration must, in the steady state, be effected by some membrane based mechanism which consumes energy.
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Taylor J, Hattan D. Biphasic kinetics of ATP hydrolysis by calcium-dependent ATPase of the sarcoplasmic reticulum of skeletal muscle. Evidence for a nucleoside triphosphate effector site. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(17)30022-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Babcock DF, Singh JP, Lardy HA. Alteration of membrane permeability to calcium ions during maturation of bovine spermatozoa. Dev Biol 1979; 69:85-93. [PMID: 376375 DOI: 10.1016/0012-1606(79)90276-8] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Vandermeers A, Robberecht P, Vandermeers-Piret MC, Rathé J, Christophe J. Specific binding of the calcium-dependent regulation protein to brain membranes from the guinea pig. Biochem Biophys Res Commun 1978; 84:1076-81. [PMID: 728147 DOI: 10.1016/0006-291x(78)91693-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Vial C, Otokore A, Goldschmidt D, Gautheron DC. Studies on the energy-linked Ca2+ accumulation in pig heart mitochondria - role of Mg2'ons. Biochimie 1978; 60:159-69. [PMID: 667169 DOI: 10.1016/s0300-9084(78)80749-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Comparative intracellular distribution of Ca2+, Mg2+ and adenine nucleotides has been studied in pig heart by differential centrifugation or fractional extraction and has shown that Mg2+ and ATP are associated mainly with soluble fractions whereas Ca2+ and ADP are more tightly bound to subcellular structures. Ca2+ accumulation and Ca2+ stimulated respiration were studied in pig heart mitochondria under different energetic conditions in the absence or presence of phosphate. Ca2+ concentrations of about 1200 nmoles/mg protein inhibit Ca2+ accumulation, site I substrate oxidation and induce an efflux of mitochondrial Mg2+. These deleterious effects of Ca2+ on respiration occur even in the absence of phosphate or oxidizable substrate; they are completely prevented by ruthenium red only, and partially prevented by the addition of M2+ to the medium. The kinetics of Ca2+ uptake become of the sigmoidal type when Mg2+ is present. This cation strongly inhibits the rate of Ca2+ uptake in the presence of added phosphate and decreases the affinity of Ca2+ for its transport system. In the absence of phosphate, Mg2+ has no effect on Ca2+ uptake. The possible physiological implications of these findings are discussed
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Scarpa A, DiMauro S, Bonilla E, Schotland DL. Studies of fragmented sarcoplasmic reticulum from human skeletal muscle. Ann Neurol 1978; 3:194-201. [PMID: 149513 DOI: 10.1002/ana.410030303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Sarcoplasmic reticulum (SR) vesicles were isolated from muscle biopsies of 4 normal volunteers, a patient with McArdle disease (before and during contracture), and a patient with normokalemic periodic paralysis. Fractions were analyzed for purity by electron microscopy and biochemical analysis of specific marker enzymes. Adenosine triphosphate (ATP)-dependent calcium ion uptake was measured kinetically by the absorbence changes of murexide, a metallochromic indicator of ionized Ca++ concentrations, in the absence of oxalate or other calcium-complexing anions. In these experiments, time resolution of the Ca++ transport rate was limited by the manual mixing of reagents, which occurred in 1 to 3 seconds. In 1 case the "true" initial velocity of Ca++ uptake was measured by rapid mixing of ATP in a stopped-flow apparatus and by following the change in absorbence of murexide in a storage oscilloscope. In SR from normal human muscle the ATP-dependent Ca++ uptake was 3.5 nmoles per second per milligram of protein for the first 5 seconds after ATP mixing. Fast kinetic experiments showed that Ca++ uptake proceeded linearly for the first 500 msec at a rate of 9 nmoles per second per milligram of protein (at 25 degrees C) and then progressively declined to reach steady-state levels in 40 to 50 seconds. No abnormality of Ca++ transport was found in SR vesicles from the patient with McArdle disease and the patient with normokalemic periodic paralysis.
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Scarpa A, Malmstrom K, Chiesi M, Carafoli E. On the problem of the release of mitochondrial calcium by cyclic AMP. J Membr Biol 1976; 29:205-8. [PMID: 185387 DOI: 10.1007/bf01868960] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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CROMPTON M, SIGEL E, SALZMANN M, CARAFOLI E. A Kinetic Study of the Energy-Linked Influx of Ca2+ into Heart Mitochondria. ACTA ACUST UNITED AC 1976. [DOI: 10.1111/j.1432-1033.1976.tb10927.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Luthra R, Olson MS. Studies of mitochondrial calcium movements using chlorotetracycline. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 440:744-58. [PMID: 822874 DOI: 10.1016/0005-2728(76)90056-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. The association of calcium with isolated rat liver mitochondrial membranes under various metabolic conditions was monitored using the fluorescent chelate probe, chlorotetracycline. Chlorotetracycline fluorescence increased markedly during energized calcium uptake in the absence of a permeant anion. Uncoupler and a respiratory chain inhibitor caused a rapid decrease in chlorotetracycline fluorescence when added either before or after calcium. During calcium uptake experiments concentrations of calcium exceeding 100 muM caused a transient fluorescence increase followed by an extensive decrease in fluorescence. 2. Changes in the chlorotetracycline-associated fluorescence of the mitochondrial suspensions were correlated with the uptake of exogenous 45Ca. A positive correlation was observed between fluorescence and energized 45Ca uptake in the absence of permeant anions. Addition of the permeant anion, phosphate, caused an extensive decrease in chloretetracycline fluorescence but an enhanced uptake of exogenous 45Ca. 3. The interaction of endogenous mitochondrial calcium with the fluorescent chelate probe was studied under a number of experimental conditions using mitochondria labeled during preparation with 45Ca. Endogenous 45Ca was lost rapidly from the mitochondria upon treatment with uncoupler, antimycin A, and A23187. Potassium phosphate and EGTA had no effect on the endogenous calcium as measured by either the 45Ca content of the mitochondria or the fluorescence of the probe. 4. Mitochondria treated with antimycin A lost most of their endogenous 45Ca within 3 min; subsequent energization of the mitochondria resulted in a partial uptake of the released 45Ca but caused nearly a complete return of the chlorotetracycline fluorescence to the original level. Addition of phosphate did not change the fluorescence level but resulted in an almost complete accumulation of the 45Ca previously released. 5. Following this energized uptake of 45Ca, EGTA, p-trifluoromethoxyphenyl hydrazone of carbonyl cyanide, A23187 and calcium chloride all caused a nearly complete loss of the 45Ca from the mitochondria and, with the exception of calcium chloride, caused an extensive decrease in the fluorescence level. Hence, the apparent location and/or properties of the endogenous calcium in this rat liver mitochondrial system were altered significantly by manipulation of the energetic state of the mitochondrial membrane.
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Dipolo R, Requena J, Brinley FJ, Mullins LJ, Scarpa A, Tiffert T. Ionized calcium concentrations in squid axons. J Gen Physiol 1976; 67:433-67. [PMID: 818340 PMCID: PMC2214921 DOI: 10.1085/jgp.67.4.433] [Citation(s) in RCA: 308] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Values for ionized [Ca] in squid axons were obtained by measuring the light emission from a 0.1-mul drop of aequorin confined to a plastic dialysis tube of 140-mum diameter located axially. Ionized Ca had a mean value of 20 x 10(-9) M as judged by the subsequent introduction of CaEGTA/EGTA buffer (ratio ca. 0.1) into the axoplasm, and light measurement on a second aequorin drop. Ionized Ca in axoplasma was also measured by introducing arsenazo dye into an axon by injection and measuring the Ca complex of such a dye by multichannel spectrophotometry. Values so obtained were ca. 50 x 10(-9) M as calibrated against CaEGTA/EGTA buffer mixtures. Wth a freshly isolated axon in 10 mM Ca seawater, the aequorin glow invariably increased with time; a seawater [Ca] of 2-3 mM allowed a steady state with respect to [Ca]. Replacement of Na+ in seawater with choline led to a large increase in light emission from aequorin. Li seawater partially reversed this change and the reintroduction of Na+ brought light levels back to their initial value. Stimulation at 60/s for 2-5 min produced an increase in aequorin glow about 0.1% of that represented by the known Ca influx, suggesting operationally the presence of substantial Ca buffering. Treatment of an axon with CN produced a very large increase in aequorin glow and in Ca arsenazo formation only if the external seawater contained Ca.
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DiMauro S, Bonilla E, Lee CP, Schotland DL, Scarpa A, Conn H, Chance B. Luft's disease. Further biochemical and ultrastructural studies of skeletal muscle in the second case. J Neurol Sci 1976; 27:217-32. [PMID: 1249587 DOI: 10.1016/0022-510x(76)90063-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In the second known case of non-thyroidal hypermetabolism (Luft's disease), there were large areas of mitochondrial aggregates in all fibers. Many mitochondria were abnormally large and contained packed cristae. In isolated mitochondrial fractions, studies of oxidative phosphorylation showed defective respiratory control and normal phosphorylation capacity ("loose coupling"). Spectra and content of cytochromes were normal. Basal ATPase activity was seven times greater than normal and poorly stimulated by 2,4-dinitrophenol. The rate of energy-dependent calcium uptake by isolated mitochondria was normal, but the amount of calcium accumulated was much decreased. Calcium could not be retained and was spontaneously released into the medium within 30 seconds. "Recycling" of calcium between mitochondria and cytosol may take place in vivo and result in sustained stimulation of respiration and loose coupling.
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Sundararajan NR, Whitney RM. Murexide for determination of free and protein-bound calcium in model systems. J Dairy Sci 1975; 58:1595-608. [PMID: 426 DOI: 10.3168/jds.s0022-0302(75)84757-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The determination with murexide of free and protein-bound calcium in model systems of known composition, ionic strength, and pH was investigated. The spectra of calcium murexide in the presence of varying amounts of calcium ions indicated that the absorption maximum fo calcium murexide complex occurs at 480 nm while that of murexide ion is at 520 nm. The absorbance at 509 nm is independent of calcium ion concentration and, therefore, could be used to measure the total dye. The spectra are pH dependent but constant in the range 6.5 to 7.0. The apparent dissociation constant of calcium murexide is dependent upon ionic environment, ionic strength, and free calcium ion concentration. The relationship between the apparent dissociation constant and free calcium concentration was established. Whole casein had no effect on the absorption spectra of calcium murexide and no affinity for calcium murexide complex or murexide ion. Beta-casein, at the concentrations employed, did not influence the dissociation fo calcium murexide. At pH 7.0, ionic strength .1, and 2 C, Beta-casein bound calcium as if there were 8.65 binding sites per molecule, each of pK 2.23, corresponding to an intrinsic association constant of 168.9 liters per mole.
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Vallières J, Scarpa A, Somlyo AP. Subcellular fractions of smooth muscle. Isolation, substrate utilization and Ca++ transport by main pulmonary artery and mesenteric vein mitochondria. Arch Biochem Biophys 1975; 170:659-69. [PMID: 1190784 DOI: 10.1016/0003-9861(75)90162-9] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Case GD. Magnetic resonance studies on the mitochondrial divalent cation carrier. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 375:69-86. [PMID: 163099 DOI: 10.1016/0005-2736(75)90073-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Measurements of water proton spin relaxation enhancements (epsilon) can be used to discriminate high-affinity binding of Mn-2+ or Gd-3+ to biological membranes, from low-affinity binding. In rat liver mitochondria, epsilon b values of approx. 11 are observed upon binding of Mn-2+ to the inner membrane, while internal or low-affinity binding remains invisible to this technique. Energy-driven Mn-2+ uptake by liver mitochondria results in the subsequent decay of epsilon. Comparison of epsilon with the initial velocity of Mn-2+ uptake in rat liver mitochondria reveals a linear correlation, which holds at all temperatures between 0 degrees C and 40 degrees C, regardless of the mitochondrial protein concentration. Consequently, enhancement appears to reflect the binding of Mn-2+ to the divalent cation pump. Binding of Mn-2+ to blowfly flight muscle also results in substantial epsilon, which is associated with the glycerol-1-phosphate dehydrogenase instead of divalent cation transport. Consequently, no decay in epsilon due to uptake occurs after Mn-2+ is bound. Lanthanide ions are also bound and transported by mitochondria. Addition of Gd-3+ to pigeon heart or rat liver mitochondria results in epsilon b approximately equal to 5-6, which decays with similar kinetics in both systems. The uptake velocity of Gd-3+ in rat liver mitochondria is about 1/6 the rate with which Mn-2+ is transported. Lanthanides also diminish epsilon due to the addition of Mn-2+, and greatly retard the Mn-2+ uptake kinetics. The presence of carbonylcyanide-p-trifluoromethoxyphenylhydrazone depresses epsilon upon addition of Mn-2+ or Gd-3+ and also uncouples energy-driven uptake. On the other hand, prolonged anaerobic incubation in the presence of antimycin and rotenone exhausts the mitochondria of their energy stores, blocks the uptake of Mn-2+, but does not affect epsilon significantly. Evidently, the uncoupler-induced disappearance of divalent cation binding sites is not the result of "de-energization". Measurements of epsilon at several NMR frequencies indicate a correlation time (tau b) for carrier-bound Mn-2+ in rat liver mitochondria between 20 ns and 4 ns as one varies the temperature between 10 degrees C and 30 degrees C. The 13 Kcal/mole activation energy for tau b suggests that the 11 ns time constant at room temperature represents the movement of the Mn-11-carrier comples. On the other hand, tau b is probably approx. 100 times too short to represent the rotational motion of a carrier protein. Apparently, Mn-2+ binds to a small arm of the carrier which moves independent
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