Chloroplasts, parts The number of cells that enable photosynthesis in plants and algae is believed to have arisen over a billion years ago, when photosynthetic cyanobacteria lived in symbiosis with other primitive cellular organisms.
Replicating the development of this photosynthetic capacity in other cells today – by placing chloroplasts in animal cells – was previously considered impossible: animal cells recognize chloroplasts as foreign bodies and digest them. However, a Japanese research team changed this thinking. A technique has been developed to isolate photosynthetically lively chloroplasts from primitive algae Cyanidioschyzon and transplant them into Chinese hamster ovary (CHO) cells, a type of cultured animal cell line, and still retain their functionality.
“To our knowledge, photosynthetic electron transport has been confirmed for the first time in chloroplasts transplanted into animal cells,” he added. explains Professor Yukihiro Matsunaga from the University of Tokyo. Electron transport is a key process by which plants and algae produce chemical energy to support a variety of cellular functions.
Matsunaga’s research team managed to transfer chloroplasts by promoting phagocytosis by CHO cells, the process by which cells digest and break down foreign substances.
The research team then used fluorescence laser microscopy and super-resolution microscopy to capture cross-sectional images of the cells and observe the behavior of both cells and chloroplasts. They found that chloroplasts taken up by CHO cells were present in the cytoplasm, the liquid that fills the interior of the cell, and some of them surrounded the cell nucleus. After the chloroplasts were collected, the CHO cells showed signs of normal behavior, such as continuing to divide.
Further observations using an electron microscope showed that the structure of the chloroplast thylakoid membrane – where the enzymes necessary for photosynthesis are located – persisted for at least two days. Measurements of photosynthetic activity using microscopic imaging and pulse modulation also confirmed that photosynthetic electron transport was normal during this period. However, on the fourth day after transfer, the structure of the thylakoid membrane collapsed and the photosynthetic activity of chloroplasts decreased significantly.
These studies point to recent possibilities in tissue engineering. Artificial organs, artificial meat and layers of skin made of multiple layers of cells are narrow in growth when the tissue is exposed to low levels of oxygen. If cells containing chloroplasts could be added, it would be possible to supply oxygen to the tissue and promote growth simply by exposing it to airy.
To achieve this, however, technology is needed that will enable transplanted chloroplasts to maintain photosynthetic activity in animal cells for longer. According to the research team, in the future it will also be necessary to quantify the amount of oxygen produced by transplanted chloroplasts and the amount of carbon dioxide bound in animal cells, which can be done using a technique called isotope labeling.
The research team will now continue their research with the ultimate goal of creating “flat” cells with plant-like properties. If possible, planim cells could be a game changer for many industries, including medical research, food production and energy generation.
This story originally appeared on WIRED Japan and was translated from Japanese.