Photosynthesis—the ability to convert sunlight into chemical energy—has long been known as a hallmark of plants and algae. However, a team of researchers from the University of Tokyo recently took a significant step forward by experimenting with integrating photosynthetically active chloroplasts into cultured animal cells, aiming to create animal cells capable of self-generating energy through photosynthesis. Is this a major breakthrough in synthetic biology, or just a high-risk experiment?
Chloroplasts and Photosynthesis: A Familiar Concept
First, let’s understand what chloroplasts are. Chloroplasts are organelles in plant and algae cells that play a crucial role in photosynthesis. They use sunlight to create energy by converting carbon dioxide and water into glucose and oxygen. This process is not only essential for plant life but also has a profound impact on life on Earth, as it provides most of the oxygen in the atmosphere.
So why would scientists want to integrate chloroplasts into animal cells? The answer lies in the applications of synthetic biology—a rapidly growing field aimed at designing and creating artificial biological systems. In this case, transforming animal cells into “photosynthetic factories” could reduce dependence on external energy sources and open new opportunities for medical and environmental research.
Chloroplasts Still Functioning in Animal Cells
In their study, the scientists used chloroplasts from the red algae Cyanidioschyzon merolae, which are capable of photosynthesis, and integrated them into cultured hamster cells. The initial results showed that the chloroplasts retained their thylakoid structure and continued to perform photosynthesis within the animal cell environment. Researchers even confirmed that these chloroplasts maintained electron transport activity for photosynthesis for at least two days after being introduced into the cells.
If these results can be reproduced and sustained over the long term, they could usher in a new era of research and applications for photosynthesis in animal biology. But can we trust these results over the long term?
Can Photosynthesis Truly Be Sustained?
Although the initial results are promising, serious questions arise regarding the long-term sustainability of photosynthesis in animal cells. One important question is: What mechanisms allow chloroplasts to function in animal cells for a short period of time? Could they maintain efficient photosynthesis in long-term culture conditions?
Additionally, it is crucial to examine whether chloroplasts can exist in animal cells without triggering immune reactions or causing metabolic issues. In nature, organisms like plants and algae have evolved to support photosynthesis. Can animal cells adapt to such a completely new process without the support of appropriate evolutionary mechanisms?
Moreover, integrating chloroplasts into animal cells could lead to other issues, such as unwanted interactions with other cellular components. While the experiment demonstrated that chloroplasts can survive in animal cells for a short time, the question remains whether this function can be sustained in the conditions found in animal cells.
Potential and Challenges
While this research opens up promising possibilities in synthetic biology and biotechnology, we cannot overlook the reasonable skepticism regarding the long-term maintenance of photosynthetic activity in animal cells. However, if successful, the integration of chloroplasts into animal cells could mark a major step forward in developing artificial biological systems and provide innovative solutions to global challenges such as energy and the environment. But, like any scientific research, continued observation, testing, and validation are necessary to determine whether this is truly a breakthrough or merely an ambitious experiment.
References:
Ryota AOKI, Yayoi INUI, Yoji OKABE, Mayuko SATO, Noriko TAKEDA-KAMIYA, Kiminori TOYOOKA, Koki SAWADA, Hayato MORITA, Baptiste GENOT, Shinichiro MARUYAMA, Tatsuya TOMO, Kintake SONOIKE, Sachihiro MATSUNAGA. Incorporation of photosynthetically active algal chloroplasts in cultured mammalian cells towards photosynthesis in animals. Proceedings of the Japan Academy, Series B, 2024; 100 (9): 524 DOI: 10.2183/pjab.100.035