Related Experiment Videos
Oxygen radical generation by isolated microsomes from soybean seedlings.
1Physical Chemistry Division, School of Pharmacy and Biochemistry, University of Buenos Aires, 1113-Buenos Aires, Argentina.
Plant Physiology
|November 1, 1992
Summary
Soybean seedling microsomes generate active oxygen species, including superoxide anion, hydrogen peroxide, and hydroxyl radical. These findings highlight the role of microsomes in cellular oxidative stress in plants.
Area of Science:
- Plant biochemistry
- Oxidative stress mechanisms
- Reactive oxygen species (ROS) generation
Background:
- Microsomes are key cellular components involved in various metabolic processes.
- Active oxygen species (AOS) play dual roles in plant physiology, acting as signaling molecules and contributing to oxidative stress.
- Understanding AOS generation in plant microsomes is crucial for comprehending cellular redox homeostasis.
Purpose of the Study:
- To investigate the capacity of soybean seedling microsomes to generate active oxygen species.
- To identify the specific types of AOS produced and quantify their generation rates.
- To explore the role of transition metals and cofactors in mediating AOS production by soybean microsomes.
Main Methods:
- Isolation of microsomes from soybean (Glycine max) seedlings.
- Quantification of superoxide anion, hydrogen peroxide, and hydroxyl radical production using specific assays.
- Evaluation of the effects of different cofactors (NADPH, NADH) and ferric complexes on AOS generation.
- Comparison of AOS generation patterns with those observed in animal microsomes.
Main Results:
- Soybean microsomes exhibited significant NADPH-dependent production of superoxide anion (5.0 nmol·min⁻¹·mg⁻¹), hydrogen peroxide (1.40 nmol·min⁻¹·mg⁻¹), and hydroxyl radical (0.50 nmol·min⁻¹·mg⁻¹).
- NADH was also effective as a cofactor for oxygen radical generation.
- Microsomal membranes efficiently reduced various ferric complexes (ATP, citrate, ADP, DTPA, EDTA) in the presence of either NADPH or NADH.
- The pattern of ferric complex effectiveness on AOS production mirrored that of animal microsomes.
Conclusions:
- Soybean seedling microsomes are a significant source of active oxygen species.
- The reduction of transition metals by microsomes contributes to cellular radical steady-state concentrations.
- These findings underscore the importance of microsomal activity in plant oxidative stress physiology.