By injecting algae into their bloodstream, light was converted into oxygen. And in this miraculous way, researchers managed to save the lives of the tadpoles that had turned green in the meantime.

Frogs are remarkable critters. During their lifetime – from water to land – they practice several breathing techniques. They breathe through the gills, lungs and skin. Now, thanks to a new study, we can add another special variant. Namely… photosynthesis.

Photosynthesis
By the term “photosynthesis,” researchers refer to the process by which plants use sunlight to convert CO2 into carbohydrates that they can use to grow. But a similar technique can apparently also be used to provide oxygen to tadpoles.

Let’s start at the beginning. “We started by studying oxygen consumption in the brains of clawed frog tadpoles,” said researcher Hans Straka in an interview with Scientias.nl. “This first study confirmed that the brain uses a large amount of oxygen, but also showed that all available oxygen is immediately converted into molecules that provide energy for brain function. We then used a certain complicated method to increase the oxygen concentration, which is a relatively time-consuming task. This led us to investigate the possibility of photosynthesis. Because if we deliver the oxygen on site through photosynthesis in the brain, it could be much more effective; both in terms of time and in terms of concentrations.”

algae

In short, the researchers decided to combine plant physiology with neuroscience: harnessing the power of photosynthesis to supply nerve cells with oxygen. The researchers decided to enlist the help of certain algae. This idea does not seem far-fetched, however. In nature, algae live harmoniously in sponges, corals and anemones, supplying them with oxygen and even nutrients. So why not in vertebrates like frogs?

bright green

The researchers placed the heads of the tadpoles in an oxygen bath and caused the oxygen concentrations to drop sharply, causing an acute oxygen shortage. Then they injected so-called green algae (Chlamydomonas renhardtii) in the hearts of the tadpoles.

Watch the video here.

With each heartbeat, the algae was pumped through the blood vessels and eventually reached the brain, causing the translucent tadpole to suddenly turn bright green. Then the team shone a bright light on the cups. And in this way, the algae saved their lives: the light was converted into oxygen, which was then pumped into the nearby cells. “The algae produced so much oxygen that they revived the nerve cells,” Straka said.

science fiction

It may sound a bit like science fiction, Straka admits. “But for me it was just a logical combination of experiments, techniques and concepts,” he says. “It concerns different biological principles that have been brought together. It wasn’t even that uncommon for us to combine those different ingredients. It was only after we did the experiments, everything worked out, and we talked to others about our findings, that I realized that most people were fascinated and intrigued by the approach and considered it almost science fiction.”

Human application

While it is of course a wonderful experiment to oxygenate choking tadpoles in a rather remarkable way, the research may also offer solutions for humans. “The injection of microorganisms such as algae may one day help provide extra oxygen in the event of oxygen starvation in humans,” Straka suggests. Think of situations where oxygen deficiency plays tricks, such as during a stroke, or in oxygen-poor environments such as underwater or at high altitude. But that is still future music. At the moment, the algae are not yet ready to be injected into our own bloodstream. “Application methods must first be improved, immune reactions elucidated and allergic reactions excluded,” emphasizes Straka.

laboratory animals

In the shorter term, the findings from the study may well contribute to in vitrostudies on organoids, or other isolated animal tissue. “Think of experiments with organs where oxygen supply is difficult, but necessary for the tissue to survive,” said the researcher. In that case, the demand for live laboratory animals that are often used for experiments may also be reduced.

All in all, the findings from the study have enormous potential. “I find this concept of bypassing the normal respiratory system (lungs or gills) particularly fascinating because of the enormous potential both in experimental science and for possible applications in human health,” Straka says. “This suggests that we have not yet reached the end of the investigation. We are only at the beginning.”