Cytochrome and Alternative Respiratory Pathways Compete for Electrons in the Presence of Pyruvate in Soybean Mitochondria

1995 ◽  
Vol 318 (2) ◽  
pp. 394-400 ◽  
Author(s):  
M.H.N. Hoefnagel ◽  
A.H. Millar ◽  
J.T. Wiskich ◽  
D.A. Day
Keyword(s):  
Alternative Respiratory Pathways

Breaking of Secondary Dormancy in Cocklebur Seeds by Cyanide and Azide in Combination With Ethylene and Oxygen, and Their Effects on Cytochrome and Alternative Respiratory Pathways

1982 ◽  
Vol 9 (1) ◽  
pp. 97 ◽  
Author(s):  
Y Esashi ◽  
H Komatsu ◽  
R Ushizawa ◽  
Y Sakai
Keyword(s):  
Seed Germination ◽  
Best Practice ◽  
Alternative Path ◽  
Secondary Dormancy ◽  
Complete Restoration ◽  
Alternative Respiratory Pathways

The mechanism by which O2, C2H4, KCN and NaN3 stimulate germination was examined using completely after-ripened, non-dormant upper seeds of Xanthium pensylvanicum Wallr. in which secondary dormancy was induced by presoaking. Although the presoaked seeds had lost the ability to respond to these chemicals applied singly, they were highly responsive to C2H4 alone, but not to O2 alone, when pretreated with KCN or NaN3. Transfer of seeds exposed to KCN or NaN3 to C2H4 under O2 enrichment was the best practice for breaking secondary dormancy. Both O2 and C2H4 stimulated total respiration of untreated seeds by increasing the ratio of alternative path flux (Valt) to cytochrome path flux (Vcyt), which had been very low during the secondary dormancy stage. Maximal values of Valt and Vcyt were obtained when O2and C2H4 were applied together. The respiration surge induced by O2 or C2H4 was also produced when the seeds were pretreated with KCN or NaN3, but it did not occur until KCN or NaN3 treatment was continued beyond 32 h. This time corresponds to that required for complete restoration of C2H4 responsiveness. The respiration surge did not occur when the KCN solution was renewed, suggesting that the operation of the cytochrome system, even if restricted, was required to develop the alternative path. In order to observe the respiration-enhancing action of C2H4 in seeds pretreated with KCN or NaN3, C2H4 had to be applied in combination with O2. This combination led to maximal fluxes of both Vcyt and Valt, although it did not significantly increase the Valt/Vcyt ratio. O2 enrichment was ineffective in stimulating germination of these seeds and in increasing the Valt/Vcyt ratio, since it stimulated the flux via the cytochrome path rather than the alternative one. It is concluded that both the large increase of Valt and the high Valt/Vcyt ratio are required for seed germination and that KCN, NaN3, O2 and C2H4 exert their actions on the germination by increasing either or both.

Effect of osmotic stress on the respiratory properties of shoots and roots of Arnica alpina

1993 ◽  
Vol 71 (8) ◽  
pp. 1102-1108 ◽  
Author(s):  
Donald E. Collier ◽  
W. Raymond Cummins
Keyword(s):  
Osmotic Stress ◽  
Alternative Pathway ◽  
Soluble Sugars ◽  
Pathway Activity ◽  
Atp Production ◽  
Cytochrome Pathway ◽  
Growth Energy ◽  
Alternative Respiratory Pathways

Arnica alpina plants were exposed to 0.3 or 0.6 M sorbitol for 5 days to investigate the effect of long-term osmotic stress on the cytochrome and alternative respiratory pathways in both shoots and roots. Exposure to 0.3 M (−0.72 MPa) sorbitol significantly reduced growth in both shoots and roots. Increased alternative pathway activity was observed in shoots, exposed to 0.3 M sorbitol whereas increased cytochrome pathway activity, with a concomitant increase in the theoretical rate of ATP production, was found in the roots. Despite a reduction in shoot and root ethanol-soluble sugars, respiration was never substrate limited. These results suggest that the reduced demand for shoot growth energy was offset by an equally increased demand for maintenance energy. In roots, however, additional ATP production was required to meet the metabolic demands of exposure to 0.3 M sorbitol. Exposure to 0.6 M (−1.44 MPa) sorbitol completely stopped shoot and root growth and decreased respiration after only 1 day. In shoots, cytochrome pathway activity was inhibited, whereas in roots both pathways were transiently stimulated. By day 5, respiration along both pathways was significantly inhibited. The possible role of the alternative pathway as an energy overflow and an energy overcharge during osmotic stress is discussed. Key words: alternative pathway respiration, Arnica alpina, ATP, cytochrome pathway respiration, osmotic stress, respiration.

scholarly journals Distribution of Denitrification among Haloarchaea: A Comprehensive Study

2021 ◽  
Vol 9 (8) ◽  
pp. 1669
Author(s):  
Jose María Miralles-Robledillo ◽  
Eric Bernabeu ◽  
Micaela Giani ◽  
Elena Martínez-Serna ◽  
Rosa María Martínez-Espinosa ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Point Of View ◽  
Nitric Oxide Reductase ◽  
Respiratory Pathway ◽  
Common Features ◽  
Alternative Respiratory Pathway ◽  
Wide Range ◽  
The Common ◽  
Alternative Respiratory Pathways ◽  
Comprehensive Study

Microorganisms from the Halobacteria class, also known as haloarchaea, inhabit a wide range of ecosystems of which the main characteristic is the presence of high salt concentration. These environments together with their microbial communities are not well characterized, but some of the common features that they share are high sun radiation and low availability of oxygen. To overcome these stressful conditions, and more particularly to deal with oxygen limitation, some microorganisms drive alternative respiratory pathways such as denitrification. In this paper, denitrification in haloarchaea has been studied from a phylogenetic point of view. It has been demonstrated that the presence of denitrification enzymes is a quite common characteristic in Halobacteria class, being nitrite reductase and nitric oxide reductase the enzymes with higher co-occurrence, maybe due to their possible role not only in denitrification, but also in detoxification. Moreover, copper-nitrite reductase (NirK) is the only class of respiratory nitrite reductase detected in these microorganisms up to date. The distribution of this alternative respiratory pathway and their enzymes among the families of haloarchaea has also been discussed and related with the environment in which they constitute the major populations. Complete denitrification phenotype is more common in some families like Haloarculaceae and Haloferacaceae, whilst less common in families such as Natrialbaceae and Halorubraceae.

scholarly journals Alternative respiratory pathways in Schwanniomyces castellii: involvement in energy production and growth.

1992 ◽  
Vol 38 (5) ◽  
pp. 457-464 ◽  
Author(s):  
LAURENT SEGUEILHA ◽  
HELENE BOZE ◽  
MAURICE L. CLAISSE ◽  
GUY MOULIN ◽  
PIERRE GALZY
Keyword(s):  
Energy Production ◽  
Alternative Respiratory Pathways

scholarly journals Decreasing Electron Flux through the Cytochrome and/or Alternative Respiratory Pathways Triggers Common and Distinct Cellular Responses Dependent on Growth Conditions

2014 ◽  
Vol 167 (1) ◽  
pp. 228-250 ◽  
Author(s):  
Kristina Kühn ◽  
Guangkun Yin ◽  
Owen Duncan ◽  
Simon R. Law ◽  
Szymon Kubiszewski-Jakubiak ◽  
...  
Keyword(s):  
Electron Flux ◽  
Cellular Responses ◽  
Growth Conditions ◽  
Alternative Respiratory Pathways

Increase in the Capacities of the Cytochrome and Alternative Respiratory Pathways in Tobacco Cells Caused by 2,4-D and Kinetin

1992 ◽  
Vol 140 (3) ◽  
pp. 264-268 ◽  
Author(s):  
Marcel H.N. Hoefnagel ◽  
Bert J. Van Der Zaal ◽  
Frank Van Iren ◽  
Kees R. Libbenga
Keyword(s):  
Tobacco Cells ◽  
Alternative Respiratory Pathways
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