Pamela Silver, professor of systems biology at Harvard University, asserted that bioengineering will play a key role in the future of engineering in a Jones Seminar lecture on October 2nd.
A relatively new field, bioengineering has made massive strides since it first emerged from the obscurity of college laboratories in the 1980s. The field has contributed, for example, to many of the prescription medications available in the United States today.
Silver attributes bioengineering’s success to biology’s affinity towards being engineered. The field’s main goal is to be able to define cellular behavior by programming the information cells contain.
This kind of engineering is possible because cells are predictable, much in the same way computer chips are. Cells have standardized parts, can be measured in mathematical models, and contain a modularity in genes, RNA, proteins, and cellular pathways.
Silver described how researchers have established a website containing a registry of standard biological parts to track the different cellular components that can be engineered. Though far from complete, the site describes individual pieces and functions of cells, and helps bioengineers seeking to piece together a cellular machine with a specific, intended effect—for example, taking a normal cell and converting it to a fluorescent green color.
A major development in the modularity of cells has been the manipulation of “memory”. By developing a “switch” that causes cells to change color upon contact with specific molecules, engineers are able to track their exposure to different cellular elements. This allows scientists to record the history of a disease, test the proliferation of a cancer, or track individual cells in a crowded physiological environment.
Silver’s own research has used this manipulation technique to investigate cellular photosynthesis, with the hope of discovering a clean source of bioenergy. Recently, she has been able to channel photosynthesis to produce hydrogen in cells by introducing a specific enzyme to the photosystems of the chloroplast, the cell’s photosynthesizing organelle. The enzyme, called PFOR, steals electrons excited by sunlight in the photosystems and uses them to reduce hydrogen to its gaseous form. Silver asserts that the released hydrogen could be a potential alternative power source.
Silver’s current projects aim to further explore the concept of bioenergy. In her latest project, she isolated and transplanted the glucose and fructose producing elements of the photosynthesis Calvin cycle into zebra fish. The research is ongoing, and the still-young fish have yet to eat. Ideally, Silver says, they won’t have to at all.
Christina
I’m a graduate student in Dr. Silver’s lab working on some of the projects you’ve described. I just wanted to clarify a few things to make sure that people understand how much we’ve gotten done and what challenges still remain.
We are very interested in engineering photosynthetic cells to produce hydrogen, but we’re still not there yet. We use PFOR in non-photosynthetic bacteria as a source of electrons for the hydrogenase enzyme, which in turn is able to produce hydrogen gas from these electrons and protons from the environment. We use this pathway to study the biology of the hydrogenase enzyme and to try and make it better.
The photosynthetic fish idea is another fun project, but not quite ready to fully feed the fish yet. We don’t transplant photosynthetic machinery into the genome of the zebrafish, we simply inject engineered photosynthetic organisms into the fish embryos. As the embryo grows into a fish, the photosynthetic bacteria may be able to act as “chloroplasts” inside of the fish cells.
One main point that is really important is that cells aren’t really predictable yet, that’s what we’re all working on! Making computer models and trying to make standardized genes that can be used in different organisms is still a difficult area of current research. We can use some of the natural modularity that exists in cells to make it easier, but we are a long way from cells being like computer chips!
qiudy
how the idea of creating photosynthetic human? no food is need for human anymore,just sunlinght?