Related Experiment Video
Updated: Jan 2, 2026
07:47
Live Imaging of the Mitochondrial Glutathione Redox State in Primary Neurons using a Ratiometric Indicator
Published on: October 20, 2021
3.2K
Plasma membrane NADH oxidase is gravi-responsive.
1Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907-1333, USA.
Plant Physiology and Biochemistry : PPB
|September 7, 2001
Summary
Soybean (Glycine max) NADH oxidase activity responds to gravity. This enzyme
Area of Science:
- Plant physiology
- Biochemistry
- Gravitational biology
Background:
- NADH oxidase is an enzyme involved in cellular respiration.
- Plant growth and development are influenced by gravity (gravitropism).
- The enzymatic mechanisms underlying gravitropism are not fully understood.
Purpose of the Study:
- To investigate the gravi-responsiveness of NADH oxidase activity in soybean.
- To determine if NADH oxidase activity is linked to plant growth responses to gravity.
Main Methods:
- Measurements of NADH oxidase activity in intact soybean hypocotyl tissue sections and isolated plasma membrane vesicles.
- Exposure of tissue sections to different gravitational conditions (1 x g, horizontal, inverted) for varying durations.
- Application of centrifugal forces (10-400 x g) to tissue sections and vesicles.
Main Results:
- NADH oxidase activity showed inhibition at shorter durations (≤20 min) and stimulation at longer durations (≥30 min) under 1 x g.
- Inverting tissue sections stimulated activity with a lag time of approximately 30 minutes.
- Centrifugal forces reversibly stimulated NADH oxidase activity up to 2-fold.
- Both stimulated and non-stimulated activities exhibited oscillations with a 24-minute period.
Conclusions:
- NADH oxidase activity in soybean is sensitive to gravity and mechanical stimulation.
- This is the first description of a gravi-responsive enzymatic activity potentially linked to plant growth.
- Findings suggest a role for NADH oxidase in mediating plant responses to gravitational forces.
Related Concept Videos
01:26Oxygenic Photosynthesis
639
Oxygenic photosynthesis is a fundamental process in which light energy is harnessed to drive the oxidation of water, leading to the production of molecular oxygen (O₂), adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH). This process is essential for sustaining aerobic life on Earth and is primarily carried out by cyanobacteria, algae, and plants. The core of oxygenic photosynthesis lies in the thylakoid membranes, where chlorophyll pigments facilitate...
639
01:27Redox Reactions
794
Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...
794
01:22Enlargement of the Plasma Membrane
2.2K
Cell division and enlargement are processes that require precise control. The control ensures that cell division cannot proceed unless the cell has grown to a specific size. A spherical, dividing cell requires an approximately 1.6X increase in its surface area to double its volume. The secretory pathway also has a significant role in cell membrane enlargement. Secretory vesicles that bud off from the Golgi apparatus and later fuse with the plasma membrane during exocytosis are a major source of...
2.2K
01:43Electron Transport Chain: Complex III and IV
8.9K
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
8.9K
01:27Photosystem I
69.2K
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
69.2K
01:34The Z-Scheme of Electron Transport in Photosynthesis
12.8K
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
12.8K