Oxygen-tolerant

Oxygen-tolerant describes an organism, cell, or substance that can withstand and function in the presence of oxygen, even if not requiring it for survival or growth. It signifies a level of resilience to the potentially damaging effects of oxygen and its reactive derivatives, such as free radicals. This tolerance can stem from various mechanisms, including the presence of protective enzymes that neutralize these reactive oxygen species (ROS) or structural adaptations that minimize the damage caused by oxidation. The degree of oxygen tolerance varies widely, ranging from minimal to highly proficient. Organisms may still prefer anaerobic conditions, while some utilize oxygen without being strictly dependent on it. The term distinguishes these organisms from obligate anaerobes, which are killed or severely inhibited by oxygen, and obligate aerobes which require it.

Oxygen-tolerant meaning with examples

• Certain species of bacteria found in sewage treatment plants are oxygen-tolerant, allowing them to thrive in areas with fluctuating oxygen levels. They may not need oxygen for respiration, but they possess mechanisms to neutralize ROS and continue to metabolize and decompose organic matter, even under oxidative stress. Their presence aids the efficient breakdown of waste materials and the purification of wastewater. These oxygen-tolerant bacteria play an essential role in the ecosystem’s natural processes.
• Many yeast strains used in brewing and baking are oxygen-tolerant. While they perform fermentation, they are able to function in oxygen-rich conditions during the early stages of fermentation or during aeration to promote yeast growth before the fermentation process. This is crucial for ensuring a robust culture before they are placed into an anaerobic environment where fermentation can occur, leading to the production of alcohol or carbon dioxide. Their hardiness makes them easy to use in an environment where oxygen levels fluctuate.
• Specific plant cells within the roots of aquatic plants are often oxygen-tolerant. These cells facilitate the transport of oxygen to submerged tissues, allowing them to breathe even when they are underwater. While not strictly dependent on oxygen for all of their processes, they can maintain their functions effectively and are not harmed by it. The ability of plant cells to survive in fluctuating oxygen environments is critical for the survival of aquatic species.
• Some cancer cells demonstrate oxygen tolerance. This can make them more resistant to therapies that rely on damaging cells with high levels of oxygen or inducing oxygen-poor conditions. These oxygen-tolerant cells have mechanisms to neutralize the free radicals or ROS generated as a result of oxidative stress induced by treatments. This tolerance highlights a significant challenge in cancer treatment, suggesting a need for targeting these resilient adaptations.