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The ability to study the living without destroying it has been the goal of many scientists for decades. A new article in ACS Nano has paved the road towards noninvasive cellular-level examination. The only true way to study cellular dynamics is to study a single cell over time (temporally). The reason for this is the heterogeneous nature of any cell culture because no two cells are identical spatially and temporally. Each individual cell has its own set of experiences that has generated its current molecular inventory, ie. RNA molecules, metabolites, proteins, sugars, lipids, etc. Studying a community of cells gives rise to noise that makes finding significant differences incredibly difficult.
In the article entitled Compartmental Genomics in Living Cells Revealed by Single-Cell Nanobiopsy, the authors used a kind of microscopy called scanning ion conductance microscopy, or SICM, that allows for continuous sampling of a single cell over time. The authors used a nanopipette as part of the SICM and combined this with sensitive sequencing techniques resulting in a high resolution look at what genes are being expressed over time into RNA molecules. Furthermore, this technique was used to study the genomic information of individual mitochondria within a single cell without also studying the nuclear material. In other words, this new technique has resulted in the ability to not only study cellular dynamics, but go beyond that and study subcellular dynamics.
This breakthrough will have impacts across many fields from cancer biology to improving climate models.
Paolo Actis, Michelle M. Maalouf, Hyunsung John Kim, Akshar Lohith, Boaz Vilozny, R. Adam Seger, & Nader Pourmand (2013). Compartmental Genomics in Living Cells Revealed by Single-Cell Nanobiopsy ACS Nano DOI: 10.1021/nn405097u
The field of stem cell research promises to deliver truly amazing medical breakthroughs in the coming decades. However, the fundamental research needed must first provide the proof-of-principle necessary for private industry to take note. That is happening according to a recent article published in the journal Blood. Researchers at Brigham and Women’s Hospital, Harvard‘s Stem Cell Institute, in collaboration with MIT and Mass General have successfully reprogrammed a type of connective tissue stem cell line, known as mesenchymal stem cells, to produce specific surface proteins and the anti-inflammatory molecule interleukin-10.
To accomplish this, researchers injected a modified form of messenger RNA, the blueprint for protein synthesis in cells. The modified stem cells were injected into mice. Once in the mouse bloodstream, the stem cells successfully targeted sites of inflammation and reduced swelling.
This approach is promising because it targets the site in need of therapeutics and can deliver the needed drug at a level high enough to provide results. This approach is attracting attention from large pharmaceutical companies because of the capability to target the disease site itself.
Oren Levy, Weian Zhao, Luke J. Mortensen, Sarah LeBlanc, Kyle Tsang, Moyu Fu, Joseph A. Phillips, Vinay Sagar, Priya Anandakumaran, Jessica Ngai, Cheryl H. Cui, Peter Eimon, Matthew Angel, Charles P. Lin, Mehmet Fatih Yanik, & Jeffrey M. Karp (2013). mRNA-engineered mesenchymal stem cells for targeted delivery of interleukin-10 to sites of inflammation Blood DOI: 10.1182/blood-2013-04-495119
- A New Blog Series: Time for an American Renaisscience (mhrussel.wordpress.com)
- Stem cells engineered to become targeted drug factories (sciencedaily.com)
I can’t sit back and let the internet become saturated with misleading phrasing regarding by-products genetically engineered into E. coli metabolism. The latest sensation stems from the commercial production of the artificial sweetener aspartame. It was reported this week, well…read it for yourself (notice the language used):
This scientific jargon obfuscates (perhaps deliberately) a truly disturbing process:
1.) ‘Cloned microorganisms’ (which the patent later reveals to be genetically modified E. coli) are cultivated in tanks whose environments are tailored to help them thrive.
2.) The well-fed E. coli cultures defecate the proteins that contain the aspartic acid-phenylalanine amino acid segment needed to make aspartame.
3.) The proteins containing the Asp-Phe segments are ‘harvested’ (i.e. lab assistants collect the bacteria’s feces).
4.) The feces are then treated. This includes a process of methylation (adding an excess of the toxic alcohol, methanol, to the protected dipeptide).
While common sense dictates that this abomination doesn’t belong anywhere near our bodies, the patent’s authors made no secret about their belief that aspartame constitutes a safe and nutritious sweetener:
It was picked up on the UPI under “Science News” with a headline reading:
The truth about E. coli ‘poop’
First, E. coli do not ‘poop’ in the sense a human can relate. These are single-celled organisms and are rather leaky to certain molecules naturally. E. coli produce by-products, not poop. Metabolic end products are considered waste to the E. coli cell, but these natural end products include carbon dioxide, hydrogen gas, acetate (vinegar), and water. Their poop doesn’t sound so bad now does it?
The evolution of E. coli ‘poop’
E. coli has been the organism of choice for decades in myriad research areas. Simple genetic modifications like gene deletion and gene insertion are the norm and can easily be performed in a lab. Scientists and doctors have used this technique to engineer novel strains of E. coli that tweaks their metabolism to produce useful products for the general public. One great example occurred in 1978 by Herbert Boyer who inserted the gene for human insulin into E. coli. Recombinant insulin was approved by the FDA in 1982 and is now the source of 70% of the insulin sold today.
Human growth factor is another by-product engineered into E. coli to treat different forms of dwarfism. For hemophiliacs, E. coli are utilized to produce missing clotting factors like tissue plasminogen activator and factor VIII. It should be noted that before producing these therapeutics in E. coli, they were harvested from cadavers. Patients with immunodeficiency can receive recombinant interferon, used to treat viral infections, produced in bacteria.
E. coli and other bacteria are used in other industries as well. They have been modified to produce large amounts of succinate, a precursor for the solvent 1,4-butanediol. It can then be used to make some plastics and even Spandex. E. coli are also used in the production of polyhydroxybutyrate, or PHB, for the production of plastics. E. coli is also used for production of polyamines for synthesis of polyamide plastics.
Over the past decade, a lot of research has taken place in the field of renewable energy. One approach to lessen our dependence on foreign oil is the microbial conversion of cellulosic (non-food) plant material into viable fuels like ethanol and butanol. This task has given E. coli and other microbes ‘poop potential’. Through genetic engineering and synthetic biology techniques, E. coli can produce large amounts of free fatty acids which are one catalytic step away from the same diesel fuel derived from petroleum. E. coli is also engineered to produce precursors for jet fuel.
In this post, I have focused on only one microbe, E. coli, since this was the bacterium sensationalized this week in the press.
- Aspartame patent reveals E. coli feces used (upi.com)
- Aspartame: a waste product of e. Coli (yourmicrobiome.com)
- NaturalNews – Michael Ravensthorpe – Patent Confirms That Aspartame Is The Excrement Of An GM Bacteria – 25 August 2013 (lucas2012infos.wordpress.com)
- Bioengineered bacteria creates diesel like substance for advanced biofuels (ecoseed.org)