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Sven Beer - One of the best experts on this subject based on the ideXlab platform.
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The relationship of arginine groups to photosynthetic HCO _3 ^- uptake in Ulva sp. mediated by a putative anion exchanger
Planta, 1994Co-Authors: Zivia Drechsler, Rajach Sharkia, Z. Ioav Cabantchik, Sven BeerAbstract:The marine macroalga Ulva sp. can take up HCO _3 ^- via a process which chemically resembles that of anion exchange in red blood cells (Drechsler et al. 1993, Planta 191 , 34–40). In this work we explore the possibility that high-pK amino-acid residues could be functionally involved in the binding/transport of HCO _3 ^- . It was found that the specific arginyl-reacting agents phenylglyoxal and 2,3-butanedione inhibited photosynthesis of Ulva competitively with inorganic Carbon at pH 8.2–8.4 (which is close to the pH of normal seawater), where HCO _3 ^- was the predominant inorganic Carbon Form taken up. The inhibition by phenylglyoxal was irreversible at 32°C and high pH values, while that of butanedione became irreversible in the presence of borate. These interactions, as well as the protection of the irreversible phenylglyoxal-inhibition by inorganic Carbon and by the membrane-impermeant agents 4,4′-diisothiocyanostilbene 2,2′-disulfonate and 4,4′-dinitrostilbene-2,2′-disulfonate indicate that arginine (and possibly also lysine) are involved in the HCO _3 ^- uptake process, probably at the plasmalemma level. The photosynthetic affinity of Ulva to external inorganic Carbon gradually decreased with increasing pH from 8.2 to 10.5, and this decrease parallels the decline in protonation of amino acids with a pK of around 10. Based on this inFormation, as well as the inhibition studies, it is suggested that arginine and lysine residues are essential proteinaceous constituents involved in anionic inorganic Carbon (HCO _3 ^- and possibly also CO _3 ^2- ) uptake into the Ulva cells.
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BiCarbonate uptake in the marine macroalga Ulva sp. is inhibited by classical probes of anion exchange by red blood cells
Planta, 1993Co-Authors: Zivia Drechsler, Rajach Sharkia, Z. Ioav Cabantchik, Sven BeerAbstract:We demonstrate in this work that HCO _inf3 ^sup− uptake in the marine macroalga Ulva sp. features functional resemblances to anion transport mediated by anion exchangers of mammalian cell membranes. The evidence is based on (i) competitive inhibition of photosynthesis by the classical red-blood-cell anion-exchange blockers 4,4′-dinitrostilbene-2,2′-disulfonate and 4-nitro-4′-isothiocyanostilbene-2,2′-disulfonate under conditions where HCO _inf3 ^sup− , but not CO_2, was the inorganic Carbon Form taken up; (ii) inhibition of HCO _inf3 ^− uptake by pyridoxal phospate, indicating the involvement of lysine residues in the binding/translocation of HCO _inf3 ^sup− ; and (iii) inhibition of HCO _inf3 ^sup− (but not of CO_2) uptake by exofacial trypsin treatments, indicating the functional involvement of a plasmalemma protein. It is suggested that HCO _inf3 ^sup− uptake mediated by such a putative anion transporter can be a fundamental step in providing inorganic Carbon for the CO_2-concentrating system of marine marcoalgae in an environment where the HCO _inf3 ^sup− concentration is high, but the CO_2 concentration and rates of uncatalyzed HCO _inf3 ^sup− dehydration are low.
Charles Harrison - One of the best experts on this subject based on the ideXlab platform.
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Improvement in coke Carbon Form through induction heating
Fuel, 1994Co-Authors: Hardarshan S Valia, Charles HarrisonAbstract:Induction heating of coals was carried out to study Carbon Form modifications. Four metallurgical coals were Carbonized at 1000 °C in an air melt (45.4 kg) induction furnace in a continuous flow of argon. Selected coke properties were determined. The properties of resultant coke samples were compared with the properties of coke produced from the same coals made through radiant heating at normal Carbonization rate and at a higher Carbonization rate. It was found that the coke produced from induction heating resulted in an improvement in Carbon Form and an improvement in hot strength properties of coke. The induction heating concept can be utilized in a continuous coke-making process. © 1994.
Zivia Drechsler - One of the best experts on this subject based on the ideXlab platform.
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The relationship of arginine groups to photosynthetic HCO _3 ^- uptake in Ulva sp. mediated by a putative anion exchanger
Planta, 1994Co-Authors: Zivia Drechsler, Rajach Sharkia, Z. Ioav Cabantchik, Sven BeerAbstract:The marine macroalga Ulva sp. can take up HCO _3 ^- via a process which chemically resembles that of anion exchange in red blood cells (Drechsler et al. 1993, Planta 191 , 34–40). In this work we explore the possibility that high-pK amino-acid residues could be functionally involved in the binding/transport of HCO _3 ^- . It was found that the specific arginyl-reacting agents phenylglyoxal and 2,3-butanedione inhibited photosynthesis of Ulva competitively with inorganic Carbon at pH 8.2–8.4 (which is close to the pH of normal seawater), where HCO _3 ^- was the predominant inorganic Carbon Form taken up. The inhibition by phenylglyoxal was irreversible at 32°C and high pH values, while that of butanedione became irreversible in the presence of borate. These interactions, as well as the protection of the irreversible phenylglyoxal-inhibition by inorganic Carbon and by the membrane-impermeant agents 4,4′-diisothiocyanostilbene 2,2′-disulfonate and 4,4′-dinitrostilbene-2,2′-disulfonate indicate that arginine (and possibly also lysine) are involved in the HCO _3 ^- uptake process, probably at the plasmalemma level. The photosynthetic affinity of Ulva to external inorganic Carbon gradually decreased with increasing pH from 8.2 to 10.5, and this decrease parallels the decline in protonation of amino acids with a pK of around 10. Based on this inFormation, as well as the inhibition studies, it is suggested that arginine and lysine residues are essential proteinaceous constituents involved in anionic inorganic Carbon (HCO _3 ^- and possibly also CO _3 ^2- ) uptake into the Ulva cells.
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BiCarbonate uptake in the marine macroalga Ulva sp. is inhibited by classical probes of anion exchange by red blood cells
Planta, 1993Co-Authors: Zivia Drechsler, Rajach Sharkia, Z. Ioav Cabantchik, Sven BeerAbstract:We demonstrate in this work that HCO _inf3 ^sup− uptake in the marine macroalga Ulva sp. features functional resemblances to anion transport mediated by anion exchangers of mammalian cell membranes. The evidence is based on (i) competitive inhibition of photosynthesis by the classical red-blood-cell anion-exchange blockers 4,4′-dinitrostilbene-2,2′-disulfonate and 4-nitro-4′-isothiocyanostilbene-2,2′-disulfonate under conditions where HCO _inf3 ^sup− , but not CO_2, was the inorganic Carbon Form taken up; (ii) inhibition of HCO _inf3 ^− uptake by pyridoxal phospate, indicating the involvement of lysine residues in the binding/translocation of HCO _inf3 ^sup− ; and (iii) inhibition of HCO _inf3 ^sup− (but not of CO_2) uptake by exofacial trypsin treatments, indicating the functional involvement of a plasmalemma protein. It is suggested that HCO _inf3 ^sup− uptake mediated by such a putative anion transporter can be a fundamental step in providing inorganic Carbon for the CO_2-concentrating system of marine marcoalgae in an environment where the HCO _inf3 ^sup− concentration is high, but the CO_2 concentration and rates of uncatalyzed HCO _inf3 ^sup− dehydration are low.
Hardarshan S Valia - One of the best experts on this subject based on the ideXlab platform.
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Improvement in coke Carbon Form through induction heating
Fuel, 1994Co-Authors: Hardarshan S Valia, Charles HarrisonAbstract:Induction heating of coals was carried out to study Carbon Form modifications. Four metallurgical coals were Carbonized at 1000 °C in an air melt (45.4 kg) induction furnace in a continuous flow of argon. Selected coke properties were determined. The properties of resultant coke samples were compared with the properties of coke produced from the same coals made through radiant heating at normal Carbonization rate and at a higher Carbonization rate. It was found that the coke produced from induction heating resulted in an improvement in Carbon Form and an improvement in hot strength properties of coke. The induction heating concept can be utilized in a continuous coke-making process. © 1994.
Z. Ioav Cabantchik - One of the best experts on this subject based on the ideXlab platform.
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The relationship of arginine groups to photosynthetic HCO _3 ^- uptake in Ulva sp. mediated by a putative anion exchanger
Planta, 1994Co-Authors: Zivia Drechsler, Rajach Sharkia, Z. Ioav Cabantchik, Sven BeerAbstract:The marine macroalga Ulva sp. can take up HCO _3 ^- via a process which chemically resembles that of anion exchange in red blood cells (Drechsler et al. 1993, Planta 191 , 34–40). In this work we explore the possibility that high-pK amino-acid residues could be functionally involved in the binding/transport of HCO _3 ^- . It was found that the specific arginyl-reacting agents phenylglyoxal and 2,3-butanedione inhibited photosynthesis of Ulva competitively with inorganic Carbon at pH 8.2–8.4 (which is close to the pH of normal seawater), where HCO _3 ^- was the predominant inorganic Carbon Form taken up. The inhibition by phenylglyoxal was irreversible at 32°C and high pH values, while that of butanedione became irreversible in the presence of borate. These interactions, as well as the protection of the irreversible phenylglyoxal-inhibition by inorganic Carbon and by the membrane-impermeant agents 4,4′-diisothiocyanostilbene 2,2′-disulfonate and 4,4′-dinitrostilbene-2,2′-disulfonate indicate that arginine (and possibly also lysine) are involved in the HCO _3 ^- uptake process, probably at the plasmalemma level. The photosynthetic affinity of Ulva to external inorganic Carbon gradually decreased with increasing pH from 8.2 to 10.5, and this decrease parallels the decline in protonation of amino acids with a pK of around 10. Based on this inFormation, as well as the inhibition studies, it is suggested that arginine and lysine residues are essential proteinaceous constituents involved in anionic inorganic Carbon (HCO _3 ^- and possibly also CO _3 ^2- ) uptake into the Ulva cells.
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BiCarbonate uptake in the marine macroalga Ulva sp. is inhibited by classical probes of anion exchange by red blood cells
Planta, 1993Co-Authors: Zivia Drechsler, Rajach Sharkia, Z. Ioav Cabantchik, Sven BeerAbstract:We demonstrate in this work that HCO _inf3 ^sup− uptake in the marine macroalga Ulva sp. features functional resemblances to anion transport mediated by anion exchangers of mammalian cell membranes. The evidence is based on (i) competitive inhibition of photosynthesis by the classical red-blood-cell anion-exchange blockers 4,4′-dinitrostilbene-2,2′-disulfonate and 4-nitro-4′-isothiocyanostilbene-2,2′-disulfonate under conditions where HCO _inf3 ^sup− , but not CO_2, was the inorganic Carbon Form taken up; (ii) inhibition of HCO _inf3 ^− uptake by pyridoxal phospate, indicating the involvement of lysine residues in the binding/translocation of HCO _inf3 ^sup− ; and (iii) inhibition of HCO _inf3 ^sup− (but not of CO_2) uptake by exofacial trypsin treatments, indicating the functional involvement of a plasmalemma protein. It is suggested that HCO _inf3 ^sup− uptake mediated by such a putative anion transporter can be a fundamental step in providing inorganic Carbon for the CO_2-concentrating system of marine marcoalgae in an environment where the HCO _inf3 ^sup− concentration is high, but the CO_2 concentration and rates of uncatalyzed HCO _inf3 ^sup− dehydration are low.