A new study has found that living organisms emit a faint light signal, known as ultraweak photon emission (UPE), even without external excitation. Researchers from the University of Calgary have discovered that UPE varies depending on the organism’s vitality and exposure to stress factors.
In mice, UPE intensity was linked to their overall health, with live mice emitting more light than recently dead mice. However, in plants, UPE varied depending on environmental conditions such as temperature changes, injury, and chemical treatments.
The researchers believe that UPE plays a crucial role in the cellular stress response, producing reactive oxygen species (ROS) that act as signaling molecules. When organisms encounter stress, they activate biochemical pathways that generate ROS, leading to UPE.
Unlike bioluminescence, UPE is a low-intensity light signal that falls within the spectral range of 200-1,000 nm and is invisible to the human eye. This faint light has been detected in various life forms, including single-celled organisms, bacteria, plants, animals, and even humans.
The study’s findings suggest that UPE could be a powerful tool for diagnostics and medical research, allowing researchers to monitor stress responses and injuries non-invasively. The researchers used advanced imaging techniques to visualize UPE changes in living and dead mice, as well as stressed plant tissues.
Their results revealed that live mice emitted robust light signals, while those that were euthanized showed nearly extinguished emissions. In plants, temperature increases and injuries led to increased UPE intensity, with injured sites being consistently brighter than uninjured parts.
The study establishes that UPE can serve as a sensitive indicator of vitality in animals and stress responses in plants, making it an exciting area for future research and potential medical applications.
Source: https://phys.org/news/2025-05-emit-faint-extinguishes-death.html