Research and Design Project: Biopharmaceuticals and Insulin-generating Enteric Bacteria
Research: The Use of Synthetic Biology in the Detection of Tuberculosis
Biopharmaceuticals are medical drugs such as interferons, vaccines, and hormones produced
using biotechnology. The first example of a biopharmaceutical was insulin produced
biosynthetically using recombinant human DNA. Humulin, as it is marketed, is the product of
genetic engineering. Synthetic biology aims to create entirely new biopharmaceuticals by using
engineering processes to synthesize new biological molecules. This presents opportunities to
learn more about disease mechanisms and processes while also synthesizing new drugs to
overcome drug-resistance, a growing problem in medicine.
Currently one of the main diseases being combated using biopharmaceuticals developed
using synthetic biology is extremely drug resistant and multidrug resistant tuberculosis.
Tuberculosis is a highly infectious disease caused by Mycobacterium tuberculosis
most commonly affects the pulmonary system, spread by the transmission of respiratory fluids
from one person to another, usually by sneezing or coughing. In healthy individuals, the immune
system is usually able to prevent the bacteria from causing an active infection, but they still carry
the disease and can spread it to others. This latent form of tuberculosis is present in about one-
third of the world’s population. Tuberculosis is still a devastating disease in the developing
world and causes the second most deaths due to an infectious agent, after HIV/AIDS. An
especially dangerous strain of tuberculosis is multidrug resistant tuberculosis (MDR-TB), which
does not respond to isoniazid and rifampicin, the two most effective and standard tuberculosis
antibiotic treatments. Extensively drug resistant tuberculosis (XDR-TB) responds to even fewer
drugs than MDR-TB. In 2011, there were 630,000 cases of MDR-TB, about 9% of which were
Researchers are using synthetic biology to create new drugs to combat MDR-TB and
XDR-TB. By synthesizing new drugs, it is hoped to discover an antibiotic that MDR-TB and
XDR-TB will respond to and even be more effective than existing treatments. One problem
being solved in drug discovery using synthetic biology is screening potential drugs for
effectiveness. One of the most powerful tuberculosis drugs is ethionamide, a last line of defense
against tuberculosis. Ethionamide is converted by EthA into a form that kills the bacterium.
However, some tuberculosis bacteria produce EthR, which inhibits EthA, rendering ethionamide
ineffective as an antibiotic. Wilfred Weber and his team developed a synthetic gene circuit to
determine drugs that could inhibit the protein EthR (thereby rendering ethionamide ineffective).
In the presence of a suitable inhibitor, a color change would occur. Using this screening process
developed by synthetic biology, a nontoxic, cell permeable was identified: 2-phenylethyl-
butyrate. When tested, 2-phenylethyl-butyrate effectively shut off resistance to ethionamide in
In addition to developing a drug that helps solve the problem of drug-resistant
tuberculosis, this process of using synthetic gene circuits to screen chemicals for effectiveness
and nontoxicity as drugs could be applied to other diseases. For example, this system could be
applied to find drugs to inhibit the resistance of other pathogens such as MRSA to certain
antibiotics. This system of screening for drugs could also be utilized to develop more effective
Synthetic biology provides many opportunities for advancement in biopharmaceuticals,
ranging from the development of new drugs to methods of overcoming drug-resistance. As the
field of synthetic biology continues to develop, it will certainly play an important role in the
development of more effective medicines and treatments.
"Expanding Nature’s Toolkit: How Synthetic Biology Is Changing the Face of
. N.p., 2012. Web. 8 July 2013.
Tomilson, Catherine. "Ethionamide." TB Online
. Global Tuberculosis Community Advisory
Weber, Wilfried, Ronald Schoenmakers, Bettina Keller, Marc Gitzinger, Thomas Grau, Marie
Daoud-El Baba, Peter Sander, and Martin Fussenegger. "A Synthetic Mammalian Gene
Circuit Reveals Antituberculosis Compounds." Proceedings of the National Academy of
Sciences of the United States of America
105.29 (2008): 9994-998. Web. 6 July 2013.
Weber, Wilfried. "Synthetic Biology in Drug Discovery and Combating Drug Resistance."
Lecture. Synthetic Biology Workshop - From Science to Governance. Sofitel Hotel,
Brussels. 18 Mar. 2010. Public Health
. European Commision. Web. 6 July 2013.
World Health Organization. "Tuberculosis (TB)." WHO
. United Nations, 2013. Web. 7 July
Design: Insulin-generating Enteric Bacteria
All persons affected by type 1 diabetes mellitus must receive injections of insulin or wear an
insulin pump in order to survive, as their bodies do not produce insulin due to the destruction of
beta cells in the islets of Langerhans. About 40% of those affected by type 2 diabetes (caused by
insulin resistance) are treated with insulin injections. This treatment will focus mainly on type 1
diabetes, but could easily be used for the treatment of type 2 diabetes as well. The body regulates
blood sugar primarily through a feedback cycle using insulin and glycogen. The release of
insulin allows cells to take in sugar, lowering blood sugar. When blood sugar is too low,
glycogen is released, prompting the liver to release sugars into the bloodstream. Type 1 diabetic
patients do not produce insulin due to the destruction of beta-cells in the pancreas while type 2
diabetic patients are insulin resistant. The possibility of synthesizing bacteria that could exist
within the body to produce insulin (or insulin substitutes) could be effectively used in order to
treat diabetes, removing needle sticks, blood sugar highs and lows, and provide a more flexible
As previously stated, the current options for the treatment of type 1 diabetes mellitus are
insulin injections and insulin pumps. Both provide problems and inconveniences for diabetic
patients. Insulin injections require daily injections at various sites on the body, which are
effective at delivering insulin but cause discomfort and be inconvenient for diabetics.
Additionally, blood glucose highs and lows may occur as a result of insulin injections. However,
they are more inexpensive and easier to use than insulin pumps. Insulin pumps deliver more
precise amounts of insulin and can be adjusted to suit lifestyles and are thus more flexible.
However, insulin pumps require extensive training and they must be attached to the body at all
times, causing inconvenience and a constant reminder of diabetes. As methods of treating
diabetes, both insulin injections and pumps are effective but cause daily inconveniences for
This design project focuses mainly on the problem of having enteric bacteria (in this case,
) produce insulin at the proper times, i.e. in response to the consumption of glucose and
other carbohydrates by the diabetic patient. In this design, the absence of glucose will inhibit the
production of insulin, since there is already a built in detector for the presence or absence of
glucose in bacterial cells. In the absence of glucose, bacteria such as E. coli
glyoxylate cycle to synthesize carbohydrates. Succinate, one of the intermediates in the
glyoxylate cycle, is the inducer for insulin production in this system. Because the presence of
succinate is an internal stimulus in response to a lack of glucose in the environment, it is useful
as an inducer for a system. The absence of succinate within the cell (indicating the presence of
glucose in the environment, i.e. the gastrointestinal tract) would allow for the expression of the
LuxS gene, producing the LuxS enzyme, which produces autoinducer-2 (AI-2). AI-2 is a
signaling molecule utilized in a process known as quorum sensing. Normally, quorum sensing
allows bacteria to “sense” the presence of other bacteria and work in unison when a certain
number of bacteria or present. In this system, a modified version of quorum sensing is used to
“signal” other bacteria when a sufficient number of other bacteria are not producing succinate,
indicating that there is a large amount of glucose present. When AI-2 reaches a certain
concentration, the bacteria will release insulin into the small intestine. This is accomplished
using a two-component signaling system. AI-2 binds to the lsr transporter and is taken into the
cell where it is phosphorylated, becoming phospho-AI-2. Phospho-AI-2 binds to a repressor
known as LsrR. This turns on the lsr promoter, allowing the open reading frame coding for
insulin to be expressed. The open reading frame contains both the human insulin gene (INS) and
a TAT peptide export signal gene. The TAT peptide export signal allows insulin to easily leave
without having to use complex biochemical processes, making it optimal for this system.
For this system, if it were working “perfectly”, in the absence of glucose no insulin
would be produced and in the presence of glucose insulin would
be produced, as seen in the truth
However, in actuality, it is likely that a small amount of insulin would be produced even in the
absence of glucose. In reality, however, this is not necessarily a negative. Insulin pumps, the
technology on which this design is some what based produce a low level of basal insulin
throughout the day to prevent highs and lows in blood glucose levels. Therefore, a small amount
of insulin being produced continuously despite the absence of glucose (which is likely to occur
IGEBs present many advantages over current technology in insulin therapy. The main
disadvantages of insulin injections and insulin pumps are the inconveniences they provide for
diabetics. Insulin pumps resolve many of the problems present with insulin injections, while
providing disadvantages as well. IGEBs aim to resolve problems presented by insulin pumps.
One of the main issues of insulin pumps is the physical pump that is constantly attached to the
body, providing discomfort. IGEBs are a completely internally contained system, requiring no
external devices. IGEBs also are completely self-adjusting, requiring no external output to adjust
production of insulin levels. Insulin pumps require the patient to adjust insulin levels when
eating or exercising. However, IGEBs will adjust without requiring human input, using the
system described in the previous section. Additionally, IGEBs retain many of the advantages of
insulin pumps, including a more flexible lifestyle and reducing blood sugar highs and lows.
However, IGEBs also face many potential problems. One of the largest issues is how the
bacteria will survive the gastrointestinal tract. If the bacteria are ingested (a similar idea to
probiotics), the bacteria (or the capsule surrounding them) must be able to withstand the acidic
conditions of the stomach. The next potential problem is the bacteria adhering to the villi in the
small intestine without being flushed out by the body, which could require displacing the
existing gut flora. Another issue is ensuring that enough insulin is absorbed into the bloodstream
by the small intestine. Studies have shown that it is possible for insulin to be absorbed through
the small intestine, but it is still unclear how much can be absorbed. Another issue is preventing
the bacteria from mutating into a less than desirable form that could harm the patient, or
transferring its genes through conjugation to other gut flora, which could result in the patient
The testing of this system would involve observing the production of insulin by these
bacteria in the absence and presence of glucose. The bacterial cells would be exposed to cycles
of absence and presence of glucose of varying lengths of time and amounts of glucose. Insulin
production would be tracked through these cycles to determine how much insulin is being
produced and when. This testing would help adjust the bacterial insulin production to ideal levels
for human insulin therapy. Further testing would also allow the development of technology to
allow IGEBs to survive in the small intestine, providing an effective means for the treatment of
Bowen, R. "Absorption of Amino Acids and Peptides." Digestion
. Colorado State University, 8
Crane, C.W., B.Sc., M.B., M.C. Path., F.R.I.C., and George R. W. N. Luntz, M.R.C.P.
"Absorption of Insulin from the Human Small Intestine." Diabetes
17 (1968): 625-27.
"Human Insulin Gene, Complete Cds." National Center for Biotechnology Information
National Library of Medicine, 12 Feb. 2001. Web. 10 July 2013.
"MetaCyc Pathway: Glyxoylate Cycle." MetaCyc
. BioCyc Database, 04 Dec. 2007. Web. 10 July
Miller, MB, and BL Bassler. "Quorum Sensing in Bacteria." Annual Review of Microbiology
(2001): 165-99. PubMed.gov
. Web. 9 July 2013.
O'Donnell, Stacy, RN, BS, CDE, and Andrea Penney, RN, CDE. "Insulin Injections vs. Insulin
Pump." Diabetes Research, Care, Education & Resources
. Joslin Diabetes Center, 11
"Part:BBa I761002 TAT Signal+INS_A." Registry of Standard Biological Parts
. IGEM, 19 Oct.
2007. Web. 9 July 2013. <http://parts.igem.org/Part:BBa_I761002>.
Shichiri, Motoaki, M.D., Nobuaki Etani, M.D., Ryuzo Kawamori, M.D., Kenkichi Karasaki,
M.D., Akira Okada, M.D., Yukio Shigeta, M.D., and Hiroshi Abe, M.D. "Absorption of
Insulin from Perfused Rabbit Small Intestine in Vitro." Diabetes
22.6 (1973): 459-
. American Diabetes Association. Web. 2 July 2013.
Taqa, ME, JL Semmelhack, and BL Bassler. "The LuxS-dependent Autoinducer AI-2 Controls
the Expression of an ABC Transporter That Functions in AI-2 Uptake in Salmonella
Typhimurium." Molecular Microbiology
42.3 (2001): 777-93. PubMed.gov
. Web. 9 July
DAVID SLOAN WILSON Trinity Institute, The Good News Now – Evolving with the Gospel of Jesus It is an honor to be invited to join this conversation. Some people have physics envy. I have preacher envy, and so this is my big, big chance. So I thank you and I look forward to communing with you during the next four days. And also, hello to the Trinity Memorial Church in Binghamton, New York,
Newton South High School Nurse Tel: 617-559-6575 Fax: 617-559-6701 MEDICATION PERMISSION FORM & POLICY This form must be completed by a health care provider and parent before any medication (over-the-counter or prescription) can be administered at school. (M.G.L. Chapter 112 § 80) Student name __________________________ School ___________Grade: ___ D.O.B.: _________