The August Krogh Distinguished Lectureship is the highest award given by the Comparative and Evolutionary Physiology section of the American Physiological Society. As the name implies, it is awarded to a distinguished physiologist who has made major and meritorious contributions to the field.
This year’s August Krogh Distinguished Lecture was awarded to Dr. Ken Olson, Emeritus Professor, Indiana University School of Medicine – South Bend. His talk at the Experimental Biology conference was titled, “A Circuitous Journey from Hagfish to Hydrogen Sulfide, Oxygen Sensing and Redox Signaling: It’s More than Just Passing Gas.”
Many people are probably familiar with antioxidants as they are widely touted for their health-promoting effects. Antioxidants are naturally created in the body but can also be provided by various foods and supplements. They are designed to help combat oxidative stress caused by the creation of reactive oxygen species (ROS). It is important to keep in mind that not all ROS are bad and that ROS play important biological roles in the body. However, unregulated ROS production is what causes oxidative “stress”.
While much research and emphasis has been placed on ROS and antioxidants, Dr. Olson’s recent research has centered on hydrogen sulfide (H2S), which has similar properties to ROS. In fact, methods to detect ROS often pick up on reactive sulfur species (RSS) as well. What that means is that we may not be getting an accurate picture of what “oxidative stress” really is if we only focus attention on ROS. In addition, many common antioxidants may be related to H2S. For example, his research showed that polysulfides in garlic oil and green tea can act as antioxidants. He also discussed how oxygen dependent metabolism of H2S may actually function in the body as a way to sense oxygen levels.
The history of H2S Dr. Olson described was fascinating. He brought up the idea that the origin of life may have started in hydrothermal vents, i.e. in an iron and sulfur-rich environment, as sulfide could interact with iron to provide a source for energy production and cell structure. In addition, eukaryotes first appeared at a time in evolution when there was little oxygen but plenty of sulfide in the environment. Because low oxygen concentrations in the body result in the formation of H2S, this may explain how H2S could act as a sensor for oxygen levels in the body.