scholarly journals A specific role for Ca2+ in the oxidation of exogenous NADH by Jerusalem-artichoke (Helianthus tuberosus) mitochondria

1981 ◽  
Vol 194 (2) ◽  
pp. 487-495 ◽  
Author(s):  
I M Møller ◽  
S P Johnston ◽  
J M Palmer
Keyword(s):  
Jerusalem Artichoke ◽  
Relative Effect ◽  
Specific Role ◽  
Nadh Oxidation ◽  
Helianthus Tuberosus ◽  
Bivalent Metal ◽  
Fixed Charges ◽  
Bivalent Cations ◽  
Bivalent Ions ◽  
Bivalent Metal Ions

1. The addition of chelators to a suspension of mitochondria in a low-cation medium containing 9-aminoacridine caused a decrease in 9-aminoacridine fluorescence. The chelators removed bivalent cations from the membranes and allowed more 9-aminoacridine to move into the diffuse layer. The relative effect of EGTA and EDTA on the fluorescence suggested that the mitochondria are isolated with about equal amounts of Ca2+ and Mg2+ on the membranes. 2. The removal of the bivalent ions by chelators resulted in the inhibition of NADH oxidation. The inhibition could not be removed by adding sufficient decamethylenebistrimethylammonium ion (DM2+) to screen the fixed charges on the membranes and restore the fluorescence of 9-aminoacridine. This observation suggests that bivalent metal ions have a specific role in the oxidation of NADH. 3. Ca2+ and not Mg2+ reversed the inhibition of NADH oxidation caused by EGTA, whereas both reversed the inhibition caused by EDTA. This suggests that Ca2+ plays a specific role and that Mg2+ reverses the inhibition caused by EDTA by displacing the bound calcium from the chelator. 4. The results are interpreted as showing that Ca2+ plays a specific role in the oxidation of external NADH in addition to its ability to screen electrostatically or bind to the fixed charges associated with the surface of the membrane.

scholarly journals Chlortetracycline and the transmembrane potential of the inner membrane of plant mitochondria

1986 ◽  
Vol 237 (3) ◽  
pp. 765-771 ◽  
Author(s):  
I M Møller ◽  
C J Kay ◽  
J M Palmer
Keyword(s):  
Membrane Potential ◽  
Transmembrane Potential ◽  
Plant Mitochondria ◽  
Jerusalem Artichoke ◽  
Fold Increase ◽  
Nadh Oxidation ◽  
Helianthus Tuberosus ◽  
Succinate Oxidation ◽  
Bivalent Cations ◽  
Carbonyl Cyanide

The oxidation of NADH or succinate by Jerusalem-artichoke (Helianthus tuberosus L.) mitochondria in the presence of chlortetracycline induced an increase in chlortetracycline fluorescence. Any treatment that prevented the formation of a transmembrane potential (as monitored by changes in safranine absorbance, A511-A533), e.g. uncoupling with carbonyl cyanide p-trifluoromethoxyphenylhydrazone, inhibition of dehydrogenase activity or electron transport, anaerobiosis or depletion of substrate, prevented the increase in chlortetracycline fluorescence or caused it to disappear. Changes in chlortetracycline fluorescence were always slower than changes in the safranine absorbance. The increase in chlortetracycline fluorescence caused by succinate oxidation had an excitation maximum at 393 nm, indicating that a Ca2+-chlortetracycline complex was involved. The increase in fluorescence was observed even in the presence of EDTA, which removes all external bivalent cations, indicating that internal Ca2+ is mobilized. Although NADH and succinate oxidations gave the same membrane potential and qualitatively had the same effect on chlortetracycline fluorescence, NADH oxidation caused a much larger (over 3-fold) increase in chlortetracycline fluorescence than did succinate oxidation. It is possible that this is connected with the Ca2+-dependence of NADH oxidation. In the presence of 2 mM external Ca2+, chlortetracycline collapsed the transmembrane potential and uncoupled succinate and duroquinone oxidation.

scholarly journals VARIABILTY AND STABILTY OF TUBER YIELD OF JERUSALEM ARTICHOKE (Helianthus tuberosus L.) / VARIABILIDAD Y ESTABILIDAD DEL RENDIMIENTO DE TUBERCULOS DEL TOPINAMBO / VARIABILITÉ ET STABILITÉ DU RENDEMENT DU TUBERCULE DE TOPINAMBUR

Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 25-32 ◽  
Author(s):  
Janoš Berenji ◽  
Vladimir Sikora
Keyword(s):  
Tuber Yield ◽  
Jerusalem Artichoke ◽  
Tuber Size ◽  
Yield Stability ◽  
Tuber Number ◽  
High Yield ◽  
Helianthus Tuberosus ◽  
Variety Trial ◽  
Stable Performance ◽  
The Stability

SUMMARYThe objective of this paper was to estimate the genetic and ecological variation as well as the stability of tuber yield per plant, tuber number per plant and tuber size of Jerusalem artichoke based on the results of a variety trial carried out with 20 different Jerusalem artichoke varieties during the period of 1994-2000. Significant genetic as well as ecologycal variation was observed for all of the traits studied. The most promissing varieties showing high tuber yield combined with high yield stability were “BT-4”, “Violet Rennes” and “UKR 4/ 82”. It is encouraging that the highest yielding varieties exibited a rather stable performance over environments.

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