101
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Wavare RA, Prusti RK, Mohanty P. Catechol stimulation of ferricyanide Hill reaction by spheroplasts of cyanobacterium, Synechococcus cedrorum: effect of temperature on catechol-stimulated oxygen evolution. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1989; 26:19-23. [PMID: 2506124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Catechol(o-dihydroxybenzene) at low concentrations (20-100 microM) stimulates FeCN-dependent O2 evolution of spheroplasts isolated from the cyanobacterium Synechococcus both in the presence and absence of DBMIB, an inhibitor of electron flow from PSII to PSI, the stimulation being two-fold with saturating concentration of (60 microM) catechol. Catechol thus appears to mediate the acceptance of electrons at the reducing side of PSII. Similarly it may act on the component of electron donor to PSII and caused the photoreduction of FeCN when O2 evolution capacity of spheroplasts is damaged by heat treatment. Analysis of the temperature effect on FeCN-supported O2 evolution by spheroplasts suggests that catechol shifts the temperature maxima to a lower temperature and thereby hastens the decay of O2 evolution capacity by heat as compared to the normal spheroplasts. Catechol also induces a change in the magnitude of activation energy for ferricyanide Hill activity of spheroplasts and lowers the transition temperature. These results suggest that lipophilic catechol brings about an alteration in membrane fluidity in cyanobacterial spheroplasts. Catechol is involved in a thermotropic destabilization of the membrane of the cyanobacterium. However, Al3+ was found to stabilize the membrane and raise the phase transition temperature. Further increase in temperature caused a gradual decline in the rate of O2 evolution.
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102
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103
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Sayeed SA, Mohanty P. Oscillations in wheat chloroplast photochemical activity: Part III--Characterization of the possible oscillators in electron transport chain. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1988; 25:625-30. [PMID: 3255676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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104
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Sabat SC, Hoshina S, Mohanty P. Action of dimethylamino p-chlorophenoxyacetate (centrophenoxine) on chloroplast photo-electron transport activity. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1987; 24:225-8. [PMID: 3125101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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105
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Mohanty N, Murthy SD, Mohanty P. Reversal of heat-induced alterations in photochemical activities in wheat primary leaves. PHOTOSYNTHESIS RESEARCH 1987; 14:259-267. [PMID: 24430739 DOI: 10.1007/bf00032709] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/1987] [Accepted: 08/05/1987] [Indexed: 06/03/2023]
Abstract
Chloroplasts isolated from elevated temperature treated 8-day-old continuous-white-light-grown wheat primary leaves lost the ability to photo-oxidize water. Also, the ability of ascorbate to donate electrons to photosystem II declined. However, a significant increase in reduced dichlorophenolindophenol-supported photosystem-I-mediated methylviologen photo-reduction activity was observed. The plants stressed at 45°C and 47°C were subsequently grown at 25°C and the partial photochemical activities were measured in chloroplasts isolated from the plants at 24-h intervals. The post stress alterations observed are (1) a significant restoration of water oxidation capacity in 45°C- and partial restoration in 47°C-treated leaves. Ascorbate-supported photochemical activities recovered more or less in similar fashion; (2) reversal of enhanced photosystem I activity in both 45°C- and 47°C-treated leaves. These results suggest that the restoration in water oxidation capacity is possible in 45°C-treated leaves and is limited by the severity of heat stress in 47°C-treated leaves. Restoration of water oxidation capacity vis-à-vis to the reversal of heat-enhanced photosystem I activity also indicates the existence of possible endogenous control for repair of alterations during the post stress.
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106
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Sabat SC, Mohanty N, Mohanty P. Heat-induced alteration in electron donation site(s) of ascorbate and ascorbate-reduced catechol in the electron transport chain of Amaranthus chloroplasts. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1986; 23:266-9. [PMID: 3583305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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107
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Grover A, Sabat SC, Mohanty P. Relative sensitivity of various spectral forms of photosynthetic pigments to leaf senescence in wheat (Triticum aestivum L.). PHOTOSYNTHESIS RESEARCH 1986; 10:223-231. [PMID: 24435369 DOI: 10.1007/bf00118287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The change in the characteristics of the absorption spectrum of chloroplasts which were isolated from the mature and senescing primary wheat leaves, was examined at various wavelengths in which the photosynthetic pigments mostly absorb. Chlorophyll (Chl) a was observed to be relatively more sensitive to leaf senescence than Chl b and carotenoids. Furthermore, the various spectral in vivo forms of Chl a, did not degrade to a similar extent; the far red absorbing forms of Chl a including species that absorb maximally at 692 nm (Chl a-692), 700 nm (Chl a-700) and 708 nm (Chl a 708) were found to be extremely sensitive to senescence induced losses. Both attached and detached senscing primary wheat leaves exhibited nearly similar pattern in the loss of photosynthetic pigments which suggests that the loss in long wavelength absorbing forms of Chl a is a selective indicator of leaf senescence.
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108
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Mohanty P, Brands JJ, Fork DC. Calcium depletion alters energy transfer and prevents state changes in intact Anacystis. PHOTOSYNTHESIS RESEARCH 1985; 6:349-361. [PMID: 24442954 DOI: 10.1007/bf00054108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/1984] [Accepted: 11/21/1984] [Indexed: 06/03/2023]
Abstract
A time-dependent loss of Photosystem II (PS II) activity seen in Anacystis nidulans grown without Ca(2+) was paralleled by a loss in chlorophyll (Chl) a fluorescence of variable yield which reflects inhibition of 'Q' reduction and of state changes. Both inhibitions were fully reversed by the addition of Ca(2+) to the growth medium. The lack of state changes in Ca(2+)-depleted cells was confirmed in 77 K fluorescence difference spectra of light versus dark-adapted cells.Absorption spectra of control and of Ca(2+)-depleted cells were identical whether measured at room temperature or at 77 K. Fluorescence emission spectra measured at 39°C (cell growth temperature) demonstrated higher yields in Ca(2+)-depleted cells compared to controls. Fluorescence emission spectra at 77 K also produced higher yields in Ca(2+)-depleted cells but the increased fluorescence at this temperature occurred principally at 683 nm. The increased relative fluorescence yield in Ca(2+)-depleted samples results from light absorbed by phycocyanin (PC), but not from light absorbed almost exclusively by Chl. The 683 run fluorescence peak probably represents increased allophycocyanin (APC) emission as intact phycobilisomes become energetically disassociated from the photosynthetic apparatus. This inferred disassociation occurred only after PSII activity was mostly inhibited in Ca(2+)-depleted cells, and was not fully reversible.
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109
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Wavare RA, Mohanty P. Al3+ ions alter temperature-induced changes in ferricyanide Hill activity of spheroplasts of Synechococcus cedrorum. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1985; 22:309-12. [PMID: 3938767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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110
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Hoshina S, Mohanty P, Fork DC. Temperature dependent changes in absorption and fluorescence properties of the cyanobacterium Anacystis nidulans. PHOTOSYNTHESIS RESEARCH 1984; 5:347-360. [PMID: 24458777 DOI: 10.1007/bf00034979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/1983] [Indexed: 06/03/2023]
Abstract
Temperature dependent changes in absorbance and fluorescence of chlorophyll a (Chl a) were analyzed in membrane fragments and in a Chl-protein complex reconstituted with lipids isolated from the cyanobacterium Anacystis nidulans. Absorbance versus temperature curves measured at 656 nm showed an inflection point at 23-24°C and at 14-16°C in the membrane fragments prepared from A. nidulans cells, grown at 39° and 25°C, respectively. Temperature-induced absorbance changes measured at 680 and 696 nm did not show clear break points. The presence of lipids was essential in order to see a clear maximum in the fluorescence versus temperature curve of Chl a in a Chl-protein complex. It is suggested that a specific form of Chl a may be associated with lipids in the thylakoid membranes and that this form of Chl a may be responsible for temperature-induced absorbance and fluorescence yield changes in this cyanobacterium.
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111
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Krishnan M, Mohanty P. Reactivation by chloride of hill activity in heat- and tris-treated thylakoid membranes from Beta vulgaris. PHOTOSYNTHESIS RESEARCH 1984; 5:185-198. [PMID: 24458606 DOI: 10.1007/bf00028531] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hill activity (photoreduction of 2,6,dichlorophenol indophenol) of heat inactivated (40°C, 3 min) and Tris-washed (0.8M, pH 8.3) thylakoids of Beta vulgaris (beet-spinach) was partially restored if they were incubated with 150 mM MgCl2 prior to the assay. Mg(NO3)2 or MgSO4 were unable to restore this activity. The extent of this reactivation was dependent upon the degree of inactivation by heating and upon the composition of the isolation and the resuspension buffer used during the heat treatment. Washing of heat-treated thylakoids with phosphate-EDTA buffer prior to incubation with MgCl2 did not affect the extent of this reactivation. Chloride ions seem to be required for the reactivation of Hill activity damaged either by heat or by Tris.Most commonly used chloroplast isolation and resuspension media, except for Tris-HCl as resuspension medium, were suitable for restoration of Hill activity in heat-damaged thylakoids by preincubation with 150 mM MgCl2 prior to the assay. Pretreatment with MgCl2 stimulated Hill activity in Tris-treated and heat-damage thylakoids if phosphate buffer was used for their resuspension. However, the same pretreatment inhibited Hill activity in unheated thylakoids isolated in Tris medium and resuspended in the same medium. On the other hand, MgCl2 pretreatment induced restoration of the Hill activity of the heated thylakoids when Tricine or Hepes was used as the resuspension medium. It appears that the presence of Tris somehow hampers the Cl(-) induced reactivation. The stimulation of Hill activity by MgCl2 treatment in unheated (control) thylakoids is possibly induced by Mg(2+) ions and not by Cl(-) ions.
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Wavare RA, Subbalakshmi B, Mohanty P. Effect of Al3+ on electron transport catalysed by photosystem I & II of photosynthesis in cyanobacterium Synechococcus spheroplasts & beet-spinach chloroplasts. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1983; 20:301-3. [PMID: 6427098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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113
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Krishnan H, Singh R, Mohanty P. Effect of temperature acclimatisation of cockroaches on the binding of Ca2+ & Mg2+ to the coxal muscle mitochondria as visualised by fluorescent probe chlorotetracycline. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1982; 19:429-31. [PMID: 7184864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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114
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Prusti RK, Srinivasan A, Mohanty P, Mookerjee S. Macromolecular constituents of Spirostomum ambiguum (major) & their modulation by ethidium bromide & caffeine treatment. INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY 1981; 19:5-8. [PMID: 6165681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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115
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Tripathy BC, Mohanty P. Zinc-inhibited Electron Transport of Photosynthesis in Isolated Barley Chloroplasts. PLANT PHYSIOLOGY 1980; 66:1174-8. [PMID: 16661598 PMCID: PMC440811 DOI: 10.1104/pp.66.6.1174] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In isolated barley chloroplasts, the presence of 2 millimolar ZnSO(4) inhibits the electron transport activity of photosystem II, as measured by photoreduction of dichlorophenolindophenol, O(2) evolution, and chlorophyll a fluorescence. The inhibition of photosystem II activity can be restored by the addition of the electron donor hydroxylamine or diphenylcarbazide, but not by benzidine and MnCl(2). These observations suggest that Zn inhibits electron flow at the oxidizing side of photosystem II at a site prior to the electron donating site(s) of hydroxylamine and diphenylcarbazide. No inhibition of photosystem I-dependent electron transport by 3 millimolar ZnSO(4) is observed. However, with concentrations of ZnSO(4) above 5 millimolar, photosystem I activity is partially inactivated. Washing Zn(2+)-treated chloroplasts partially restores the O(2)-evolving activity.
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116
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Younis HM, Mohanty P. Inhibition of electron flow and energy transduction in isolated spinach chloroplasts by the herbicide dinoseb. Chem Biol Interact 1980; 32:179-86. [PMID: 7428111 DOI: 10.1016/0009-2797(80)90076-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The mode of action of dinoseb (2-sec-butyl-4-6-dinitrophenol) on chloroplast reactions was studied. Electron flow from water or from an artificial electron donor, diphenylcarbazide (DPC), to dichlorophenol indophenol (DCPIP) was inhibited at low concentrations of the herbicide (5--10 microM) suggesting a site for dinoseb inhibition at the oxidizing side of photosystem II (PS II). Ferricyanide photoreduction was also inhibited by dinoseb. Cyclic and non-cyclic photophosphorylation and Mg2+-ATPase activity were inhibited by dinoseb, which indicates that this herbicide also acts as an energy transfer inhibitor. Among the above mentioned activities, non-cyclic photophosphorylation was the most sensitive to the inhibition by dinoseb. Ca2+-ATPase activity of solubilized heat activated chloroplast coupling factor 1 (CF1) was stimulated by dinoseb. However, the same activity was inhibited in chloroplasts, which perhaps reflect a difference in the mode of interaction of dinoseb with solubilized and membrane bound coupling factor.
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117
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Mohanty P, Mayne BC, Ke B. Further characterization of a photosystem II particle isolated from spinach chloroplasts by triton treatment. Delayed light emission. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 545:285-95. [PMID: 760780 DOI: 10.1016/0005-2728(79)90206-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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118
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Prasad U, Singhal GS, Mohanty P. Effect of protons and cations and chloroplast membranes as visualized by the bound ANS fluorescence. BIOPHYSICS OF STRUCTURE AND MECHANISM 1977; 3:259-74. [PMID: 901913 DOI: 10.1007/bf00535700] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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119
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Mohanty P, Boyer JS. Chloroplast Response to Low Leaf Water Potentials: IV. Quantum Yield Is Reduced. PLANT PHYSIOLOGY 1976; 57:704-9. [PMID: 16659555 PMCID: PMC542103 DOI: 10.1104/pp.57.5.704] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Quantum yields were measured for CO(2) fixation by sunflower (Helianthus annuus L.) leaves having various water potentials and for dichlorophenolindophenol photoreduction by chloroplasts isolated from similar leaves having various water potentials. In red radiation, the quantum yield for CO(2) was 0.076 for an attached sunflower leaf at a water potential of -3 to -4 bars but was 0.020 for the same leaf at -15.3 bars. After recovery to a water potential of -5 bars, the quantum yield rose to 0.060. Soybean (Glycine max L. [Merr.]) leaves behaved similarly. Chloroplasts from a sunflower leaf with a water potential of -3.6 bars had a quantum yield for 4 equivalents of 0.079, but when tissue from the same leaf had a water potential of -14.8 bars, the quantum yield of the chloroplasts decreased to 0.028. The decrease could not be attributed to differences in rates of respiration by the leaves or the chlorophyll content or absorption spectrum of the leaves and chloroplasts.The data are the first to demonstrate an effect of low leaf water potential on the quantum yield and they indicate that changes occurred close to the primary photochemical events of photosynthesis. The similarity in response of the leaves and chloroplasts indicates that certain changes in photosynthesis at low water potentials are attributable to the chloroplasts rather than the stomata.
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120
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Warden JT, Mohanty P, Bolton JR. Flash photolysis--electron spin resonance studies of the dynamics of photosystem I. 3. Temperature dependence of the decay of signal I. Biochem Biophys Res Commun 1974; 59:872-8. [PMID: 4370026 DOI: 10.1016/s0006-291x(74)80060-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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121
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Mohanty P. Light-induced changes in the fluorescence yield of chlorophyll a in Anacystis nidulans. I. Relationship of slow fluorescence changes with structural changes. BIOCHIMICA ET BIOPHYSICA ACTA 1973; 305:95-104. [PMID: 4198185 DOI: 10.1016/0005-2728(73)90235-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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122
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Mohanty P, Braun BZ. Light-induced slow changes in chlorophyll a fluorescence in isolated chloroplasts: effects of magnesium and phenazine methosulfate. BIOCHIMICA ET BIOPHYSICA ACTA 1973; 292:459-76. [PMID: 4634034 DOI: 10.1016/0005-2728(73)90051-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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123
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Mohanty P, Braun BZ. Fluorescence and delayed light emission in Tris-washed chloroplasts. FEBS Lett 1972; 20:273-276. [PMID: 11946436 DOI: 10.1016/0014-5793(72)80085-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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124
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Mohanty P, Mar T. Action of hydroxylamine in the red alga Porphyridium cruentum. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 253:213-21. [PMID: 5126505 DOI: 10.1016/0005-2728(71)90247-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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125
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Mohanty P, Munday JC. Time-dependent quenching of chlorophyll a fluorescence from (pigment) system II by (pigment) system I of photosynthesis in Chlorella. BIOCHIMICA ET BIOPHYSICA ACTA 1970; 223:198-200. [PMID: 5484052 DOI: 10.1016/0005-2728(70)90145-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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