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Edible Vaccines: A study of the Norwalk virus capsid protein (NVCP) in potatoes and tobacco
Jane Doe, November 4, 200X
In an age where there is the medical knowledge to vaccinate children and ward of life-threatening diseases
there are an estimated 900,000 children in the US and millions in developing nations that still remain unvaccinated
today. In addition, about $17.5 billion are lost annually to livestock and poultry products as a result of disease even
though we have the knowledge to vaccinate these animals as well. Although we have the knowledge to vaccinate
all animals alike we do not have the capability. Most parenteral (injected vaccines) are costly to develop and ship,
require refrigeration (cold-chain) as well as need trained personnel to inject it subcutaneously. These things
together make it difficult for widespread vaccination efforts particularly in developing nations where most of these
diseases remain endemic.
Edible vaccines might be a solution that will enable the positive effects of vaccines to be far reaching and to
decrease some potential hazards associated with parenteral vaccines such as toxic compounds, allergic responses
and risk of attenuated strains reverting to pathogenic strains. Edible vaccines offer a way to deliver a vaccine
orally, without the need for the cold chain, decrease costs of production and shipping and may be ideal for facing
bio-weapons and veterinary use among other benefits.
When choosing a plant to be used as a vaccine it is important that it is a hardy, palatable plant that is high
in nutritive and protein content. The plant is also one that would best be indigenous to the country in which it is to
be used and should be able to be transformed relatively easily. Tobacco plants have been used extensively in this
research but new work is being done in potatoes, tomatoes, lettuce, corn and other crop plants. Little is known
about the optimum dosage needed to confer immunity or how long this immunity lasts so there is still a lot of
research to be done.
A study conducted by Mason et al. (1996) looked at the immunogenic effect of transgenic potato tubers and
tobacco leaves carrying a Norwalk virus capsid protein (NVCP) in mice. Currently, there are no drugs are vaccines
available to treat Norwalk infections yet this virus accounts for about 42% of the viral gastroenteritis seen in the US.
Mason et al. (1996) looked at three different plasmid constructions containing the NVCP gene that were
transformed into plants using a binary T-DNA plasmid using Agrobacterium tumefaciens. They found varying
expression of the antigenic protein due to the position effect and an increase in translational expression of the
protein in plasmids that contained the TEV 5’-UTR. In addition, they obtained 0.23% and 0.37% TSP (total soluble
protein) in tobacco leaves and potato tubers respectively, which are higher levels than previous work. Finally, both
humoral and mucosal antibody responses were detected in the mice suggesting that edible vaccines might be a
viable source for immunization.
A follow up study in 2000 done by Tacket et al. looked at the human immune
response to the NVCP expressed in potatoes. Overall, 95%, 19 out of 20 volunteers developed some kind of
immune response, although the antibody increase in some cases was modest.
Sources used:
Arntzen, C. J. 2001. Keynote lecture: agricultural biotechnology. Journal of the Science of Food and Agriculture.
81: 805-809.
Carter, J. E. and W. H. R. Langridge. 2002. Plant-based vaccines for protection against infectious and
autoimmune diseases. Critical Reviews in Plant Sciences. 21(2): 93-109.
Daniell, H., Streatfield, S. J., and Wycoff, K. 2001. Medical molecular farming: production of antibodies,
biopharmaceuticals and edible vaccines in plants. Trends in Plant Science. 6(5): 219-226.
Mason, H. S., Ball, J. M., Shi, J. J., Jiang X., Estes, M. K. and Arntzen, C. J. 1996. Expression of Norwalk virus
caspid protein in transgenic tobacco and potato and its oral immunogenicity in mice. Proc. Natl. Acad. Sci.
USA. 93: 5335-5340.
Sala, F. Rigano, M. M., Barbante, A. Basso, B. Walmsley, A. M., and Castiglione, S. 2003. Vaccine antigen
production in transgenic plants: strategies, gene constructs and perspectives. Vaccine 22: 803-805.
Tacket, C. O., Mason, H. S., Losonsky, B., Estes, M. K., Levin M. M., and Arntzen C. J. 2000. Human immune
responses to a novel Norwalk virus vaccine delivered in transgenic potatoes. Journal of Infectious Diseases
182: 302-305.
1
2009 Class Abstracts appear below with my editorial additions in red. –ams
Induced Pluripotent Stem Cells: A Possible Cure For Type 1 Diabetes
Rachel Stapf, November 5, 2009
Diabetes is the most costly disease that affects our nation today, and type 1 diabetes is at an all
time high. Type 1 diabetes is an autoimmune disease in which the beta cells of the pancreas are
attacked by the patient’s own immune system. These beta cells are no longer able to produce insulin
which is responsible for converting sugars, starches and other foods into energy. This leads to an
extreme level of glucose in the blood. There are many devastating side effects to the disease. The
current treatments lead to side effects of their own, and the patient must constantly check their blood
glucose levels.
A recent experiment by Rene Maehr et al. looks into the possibility of using induced pluripotent
stem cells (iPS) to create insulin producing cells. These pluripotent cells will be generated from the
patient’s fibroblasts obtained from a skin biopsy. These fibroblasts will be infected with retroviruses
containing the necessary transcription factors. Immunostaining was used to determine if the cells had
made antibodies for the transcription factors; the cells tested positive for these antibodies and for
alkaline phosphatase enzyme activity. The induced pluripotent stem cells of made from a type 1
diabetes patient are called DiPS cells. These cells were then able to differentiate and express markers of
all three cell types, which is as expected from a pluripotent cell. In order for these DiPS cells to
differentiate into the insulin-producing cells they were aiming for, it must follow the
endothermal/pancreatic lineage. There was a stepwise protocol to lead the cells down this pathway and
to eventually obtain the beta-like cells. In order to find out if the cells are able to produce insulin in
vitro, the cells were subjected to high and low concentrations of glucose. The DiPS cells released human
C-peptide after glucose stimulation. They concluded that the cells can be differentiated into insulin
producing/glucose-responsive cells.
This research opens the door in many ways. This allows a model of the not-well understood type
1 diabetes, to be made. As of now this treatment is inefficient, and the protocol leads to a risk of
potential integration into the genome. In the near future they hope to perfect the protocol to allow this
to be a treatment.
References:
1. Maehr, Rene, Shuibing Chen, Melinda Snitow, Thomas Ludwig, Lisa Yagasaki, Robin Goland, Rudolph
Leibel, & Douglas Melton, 2009. “Generation of pluripotent stem cells from patients with type 1
diabetes.” PNAS, Vol. 106, No. 37, pg. 15768-15773
2. Shin-ichi Nishikawa, Robert A. Goldstein & Concepcion R. Nierras, 2008. “The promise of human
induced pluripotent stem cells for research and therapy.” Nature Reviews: Molecular cell biology 9:
725-729
3. Xu, Yang, 2009. “Developing induced pluripotent stem cells into human therapeutics and disease
models.” California Institute of Regenerative Medicine <http://www.cirm.ca.gov/node/2096>
2
Isolation of a human-like antibody fragment (scFv) that neutralizes
ricin activity
Nick Cummings, November 5, 2009
To the world some of the most deadly biological include weaponized organisms such as Anthrax,
smallpox and tuberculosis; among the most deadly toxins in the world include Ricin and botulism toxin.
The best defense to any biological terrorism act is the vast administration of vaccine to the general
population. Among protein toxins such as ricin which is most effective in aerosol form, the best way to
inactivate the toxin itself is by developing antibodies against it.
Ricin is a protein compound found in Castor beans. It’s composed of two chains one A-chain
which is an N-glycoside hydrolase with three domains. The B-chain is the catalytically inactive portion
that mediates entry into the cells. Upon entry into the cells the protein enters the ER where it’s believed
to be cleaved releasing the catalytic site of the protein. The protein then is capable of cleaving rRNA
where it then inactivates it essentially stopping protein synthesis.
In order to find an effective treatment toward ricin intoxication, Pelat et. all conducted an
experiment in order to find an effective antibody fragment(scFv) that can neutralize the A-chain of ricin
or ricin in general. To do this, they immunized a non-human primate with the A-chain of ricin. After a
series of shots of the A-chain between different periods of time, they extracted bone marrow cells and
lysed them freeing the mRNA encoding for ricin antibodies. After amplifying the DNA that was reversed
transcribed from the mRNA, they inserted cDNA into a series of vectors that transformed bacteria. By
using a phage displayed immune library they were able to isolate the most ideal antibody fragment that
neutralized ricin at the most efficient rate. Among the most affective antibody fragments was the 43RCA
clone which had a neutralizing efficiency of IC50 = 23 ± 3 corresponding to a molar ratio of 4
[scFv]/[ricin]. Compared with the antibody obtained from hyperimmune mouse serum (anti-dgRCA) IgG
the 43RCA cloned performed more efficiently. Another advantage of the 43RCA antibody is its
similarity to human IgG germlines, meaning it can be further humanized and be safe for human use.
Sources:
1. Pelat T, Et. All . et al. Isolation of a human like antibody fragment(scFv) that neutralizes ricin
biological activity. Biomedcentral [Internet]. [cited 2009 Nov 1]; :1-14. Available from :
http://www.biomedcentral.com/1472-6750/9/60.
2. . 2009 [cited 2009 Nov 1]. Antibody Structure and Isotopes. [Internet]. United States: abcam.
Available from: http://www.abcam.com/ps/CMS/Images/abstructure.JPG.
3. . 2009 [cited 2009 Nov 1]. Ricin and the Umbrella murder. [Internet]. CNN. Available from:
http://www.cnn.com/2003/WORLD/europe/01/07/terror.poison.bulgarian/.
4. . 2009 [cited 2009 Nov 1]. Plasmid map of pGEM-T vector. [Internet]. biovisualtech. Available
from: http://www.biovisualtech.com/bvplasmid/pGEM-T_vector.jpg.
3
GFP tagged zebrafish- a model for heat shock protein studies
Nima Maria George, November 5, 2009
The remarkable brightly glowing green fluorescent protein, GFP, was first observed in the beautiful
jellyfish, Aequorea victoria in 1962. Since then, this protein has become one of the most important tools
used in contemporary bioscience. By using DNA technology, researchers can now connect GFP to other
interesting, but otherwise invisible, proteins. With the aid of GFP, researchers have developed ways to
watch processes that were previously invisible, such as the development of nerve cells in the brain or how
cancer cells spread This glowing marker allows us to watch the movements, positions and interactions of
the tagged proteins. Osamu Shimomura was the first person to isolate GFP and to find out which part of
GFP was responsible for its fluorescence. His meticulous research laid the solid foundations on which the
GFP revolution was built.
Heat shock proteins (HSPs) function as molecular chaperones and thus play a critical role in protein
folding, intracellular trafficking of proteins, and coping with proteins denatured by heat and other stresses.
These activities are part of a cell's own repair system, called the "cellular stress response" or the "heatshock response". Accordingly, the study of stress proteins has undergone explosive growth. In recent
years, the zebrafish has been increasingly used as a model for studying heat shock proteins. In this study a
transgenic hsp27-gfp zebrafish line is established and the transgenic expression of GFP is compared with
that of the endogenous hsp27. Transgenic zebrafish were was responsive to heat shock with GFP induced
in several tissues, with the highest expression in skeletal muscle and recapitulated the expression pattern
of endogenous hsp27 RNAs. Also, the potential of transgenic zebrafish embryos for heavy metal
induction is also tested and demonstrated the inducibility of GFP expression by heavy metal (i.e., arsenic).
References
Wu Y .L, Pan X, Mudumana S. P, Wang H, Kee P. W., and Gong Z. Development of a heat shock
inducible gfp transgenic zebrafish line by using the zebrafish hsp27 promoter. Gene 408 (2007) 85-94
Chalfie M.GFP: Lighting up life. Proc Natl Acad Sci U S A. (2009) 106(25):10073-80.
Chalfie M, Tu Y, Euskirchen G, Ward W.W., and Prasher D.C. Green fluorescent protein as a marker for
gene expression. Science (1994) 263(5148):802-5.
Gerdes H.H and Kaether C.Green fluorescent protein: applications in cell biology. FEBS Lett. (1996) 24;
389(1):44-7.
Rizzuto R, Brini M, Pizzo P, Murgia M., and Pozzan T.Chimeric green fluorescent protein as a tool for
visualizing subcellular organelles in living cells. Curr Biol. 1995 5(6):635-42
4
Exercise in a Pill? It May Be Possible Thanks To The Marathon Mouse
By Grant Hutchinson
November 5, 2009
In today’s society, there is an ever increasing trend in towards obesity and obesity related
problems. Researchers have been looking into ways to fix this growing problem. Recently, marathon
mice have been used to examine whether genetic engineering could produce a solution. This transgenic
mouse has the ability to run twice the distance of a normal mouse and is able to run an hour longer than
the typical 90 minutes a normal mouse can run (Martindale 2004). This mouse also has the ability to be
resistant to obesity.
The muscles of animals consist of slow twitch (type 1) and fast twitch (type 2) muscle fibers.
These fibers have distinct characteristics and different functions inside the body. The slow twitch muscles
are rich in mitochondria and use oxidative metabolism to produce energy and the fast twitch fibers rely on
glycolytic metabolism for energy. The slow twitch muscle fibers therefore are used for endurance and the
fast twitch muscle fibers tire easily and are used for short powerful contractions.
It was recently found that altering the expression of peroxisome proliferator-activated receptor δ
resulted in mice that contained skeletal muscle that had an increased number of slow twitch muscle fibers.
Under normal conditions PPARδ is activated by exercise. It may be activated by the co-activator PGC-1α
or by an upstream signaling component (Goto et al. 2000). In the experiment a PPARδ cDNA was fused
with a human skeleton actin promoter to create a high level of activation. This study which was conducted
by Yong-Xu Wang et al. (2004) showed these mice had the ability to run significantly longer than their
wild type counterparts. Along with the increased endurance the mice showed an ability to be obesity
“resistant” even under a high calorie and high fat diet. There was also an increase in oxidation enzymes,
mitochondrial biogenesis, and type 1 fiber contractile protein. This lead to an overall discovery that the
over expression of PPARδ allows for the effects of endurance training without actual training to occur.
This means that there could be weight loss in individuals who cannot exercise due to their excessive size.
There could be the potential for solving problems that are related to obesity such as heart disease and
diabetes.
References:
Goto M, Terada S, Kato M, Katoh M, Yokozeki T, et al. 2000. “cDNA cloning and mRNA analysis of
PGC-1 in epitrochlearis muscle in swimming-exercised rats.” Biochem Biophys Res Commun 274: 350354.
Martindale D. 2004. "Muscle Twitch Switch." Scientific American 291 (6): 22-24.
Wang Y, Zhang C, Yu R, Cho H, Nelson M, et al. 2004. “Regulation of Muscle Fiber type and Running
Endurance by PPARδ.” PLoS Biology. 2:10. 1533-1539.
5
Anthrax: Therapies and Vaccinations through recombinant protective antigen (PA)
Christine Fisher, November 5, 2009
Anthrax is a disease caused by the bacteria Bacillus anthrasis. Anthrasis comes from the greek
word for coal which shares the color of the scabs from cutaneous anthrax. Anthrax comes in three
different forms; skin, gastrointestinal, and inhalation. Skin anthrax is caused when spores from the
bacteria enter a cut or abrasion in the skin and gastrointestinal anthrax is caused by the ingestion of
anthrax spores usually from contaminated meat. The most deadly form is inhalation anthrax in which
spores are inhaled into the lungs. The disease has flu-like symptoms which have led to the misdiagnosis
of the disease by multiple doctors in the past. During the early days of infection, the macrophage cells
ingest anthrax spores and transport them to the lymph nodes near the lungs where the spores turn into full
bacteria and burst through the macrophages as they multiply. The bacteria then releases toxins into the
blood stream which causes the swelling and bleeding of many tissues during the second stage. Shortly
after this stage, the blood pressure drops, oxygen levels fall, organs fail, and death rapidly follows. The
current vaccine for anthrax, anthrax vaccine adsorbed (AVA), is used for skin anthrax infections (not
including the more dangerous inhalation anthrax infection) and requires multiple injections and booster
shots. The lethal toxin (LeTx) is a major factor in anthrax pathogenesis that forms through the
combination of the protective antigen (PA) and the lethal factor (LF). Phenylalanine-427 (F427) has been
extensively studied as it is a vital contribution to the function of PA. Studies have been conducted in
which mutants are produced with mutations at the F427 residue for the dominant-negative inhibitory
(DNI) phenotype, and are tested in the presence of LF. Individual amino acid replacements were shown to
be responsible for different levels of DNI activity, for example F247D and F247N mutants had the highest
DNI activity. Both of these F247 mutants were able to inhibit LeTx based on the dose of the mutant. The
current PA vaccine is dangerous when administered to patients that are in the first stages of anthrax
infection because it increases the binding sites for the endema factor (EF) and LF. As an alternative, the
DNI phenotype occurs when PA mutants are used to coassemble with the wild-type protein (WPA) and
block its ability to move parts of enzymes across membranes (a necessary step in the pathogenesis of
anthrax). Other studies have been conducted in which recombinant PA was used in conjunction with a
synthetic double stranded RNA for polyriboinosinic-polyribocytidylic acid (pI:C). This mutant PA and
pI:C adjuvant have shown promising potential as a vaccine against inhalation anthrax based upon nasal
immunization trials in mice.
References:
Brown K. 2001. A ‘Sure Killer’ Yields to Medicine. Science. 294: 1813-1814.
Heijne G.V. 2005. Translocation of Anthrax Toxin: Lord of the Rings. Science. 309(5735): 709-710.
Sellman B.R., Mourez M., and Collier R.J. 2001. Dominant-Negative Mutants of a Toxin Subunit: An
Approach to Therapy of Anthrax. Science. 292(5517): 695-697.
Sha C., Aizhen G., Ziduo L., Yadi T., Gaobing W., Chengcai Z., Yaxing Z., and Huanchun C. 2009.
Investigation of New Dominant-Negative Inhibitors of Anthrax Protective Antigen Mutants for
Use in Therapy and Vaccination. Infection and Immunity. 77(10): 4679-4687.
Sloat B.R., Cui Z. 2006. Nasal Immunization with Anthrax Protective Antigen Protein Adjuvanted with
Polyriboinosinic–Polyribocytidylic Acid Induced Strong Mucosal and Systemic Immunities.
Pharmaceutical Research. 23(6): 1217-1226.
6
Differentiation of Embryonic Stem Cells into Neural Cells to Provide Therapeutic Benefit
Julian Capito November 5th, 2009
Embryonic stem cells are early stage developmental cells that have the ability to differentiate into
any cell type, which is called pluripotency. These pluripotent cells are obtained by extracting cells from
the embryoblast of the blastocyst embryonic stage. Once these cells are gathered, they can be cultured in
various media to induce differentiation to various cellular phenotypes. In theory, these cells, once
properly differentiated, can be transplanted into a patient to replace damaged cells that do not have the
ability to regenerate, such as muscle and CNS cells.
Embryonic stem cells that have been differentiated into neural cells have many possible
therapeutic benefits, such as repairing spinal cord damage, treatment of Parkinson’s disease and treatment
of amyotrophic lateral sclerosis. However, there are many obstacles that need to be overcome for the
practical implementation of therapeutic stem cells. There are issues over how to properly differentiate
embryonic stem cells, deliverance of the differentiated cells to the proper site, avoiding possible
tumorigenic cells once deliverance to the proper site has occurred, prevention of infection, etc. A
significant amount of research still needs to be conducted to address these various concerns.
A study conducted by Kim et al. (2009) addressed the issue of properly differentiating pluripotent
cells into a specific neural phenotype. Previous to this study, embryonic stem cells were induced to
become neural cells by the use of a medium containing retinoic acid and serum. Neural cells obtained by
this method differentiate into various neural phenotypes, such as astrocytes or motor neurons. This study
attempted to differentiate these pluripotent cells into neural cells by using a growth medium that
contained no retinoids. Additionally, the medium was serum-free and the only exogenous proteins
present were insulin, transferrin and bovine serum albumin. Basically, the goal of this experiment was to
restrict the number of proteins exposed to the undifferentiated cells to help determine which factors
contribute to the development of a specific neural phenotype. By establishing which factors contribute to
the development of a certain neural phenotype, the therapeutic use of embryonic stem cells will soon
become a reality.
References
Ehnert, Sabrina, Matthias Glanemann, Andreas Schmitt, Stephan Vogt, Naama Shanny, Natascha C.
Nussler, Ulrich Stockle, and Andreas Nussler. "The possible use of stem cells in regenerative
medicine: dream or reality?" Langenbecks Archive of Surgery 394 (2009): 985-97.
Kim, Mijeong, Ayman Habiba, Jason M. Doherty, Jason C. Mills, Robert W. Mercer, and James E.
Huettner. "Regulation of mouse embryonic stem cell neural differentiation by retinoic acid."
Developmental Biology 328 (2009): 456-71.
Legge, M., and L. M. Jones. "Stem cell spinal cord regeneration: first do no harm." Journal of Medical
Ethics 34 (2008): 838-39.
Preynat-Seauve, Olivier, Pierre R. Burkhard, Jean Villard, Walter Zingg, Nathalie Ginovart, Anis Feki,
Michel Dubois-Dauphin, Samia A. Hurst, Alex Mauron, Marisa Jaconi, and Karl-Heinz Krause.
"Pluripotent stem cells as new drugs? The example of Parkinson's disease." International Journal
of Pharmaceutics 381 (2009): 113-21.
Wang, Zi-kuan, Dong-Bo Ou, and Qiang-Sun Zheng. "Methods of maintaining human embryonic stem
cells continues to be worth studying." Cell Biology International 33 (2009): 1123-124.
7
From Stem Cells to Beta Cells: Possible Cure for Diabetes
Mellitus
Ryan Scavinski, November 10, 2009
Type 1-diabetes is caused by the autoimmune destruction of insulin producing
β-cells. To stay healthy, diabetics must frequently monitor their glucose levels in
the blood and inject themselves with insulin multiple times throughout the day.
The use of islet transplantation has been used in the past as a potential treatment.
However, problems such as the difficulty of obtaining sufficient numbers of islets or
the need for immunosuppressive medication to control rejection have limited the
widespread use of this treatment. For this reason, the use of embryonic stem (ES)
cells has been studied for their potential to produce insulin producing cells (IPCs).
The study by S. Raikwar and N. Zavazava show two main strategies for the
differentiation of embryonic stem cells into insulin producing cells. The first
strategy involves the use of embryoid body (EB) formation. An EB is an
arrangement of embryonic stem cells destined to differentiate into the precursors of
the endoderm, ectoderm and mesoderm. The treatment of EBs with multiple
growth factors gives rise to Nestin cells, which eventually differentiate into IPCs.
The second strategy involves using Definitive Endoderm (DE).
This involves
bypassing the EB formation and selectively generating the endoderm. The ES cells
which are treated with Activin A leads to the development of the DE. Retinoic acid
(RA) is also used to promote pancreatic differentiation and after maturation on
serum free medium, differentiated cells expressed islet specific markers such as Cpeptide, insulin, glucagons and glut2. These cells were then transplanted under the
renal capsules of diabetic mice of which 30% of the mice maintained normal blood
glucose levels. With further research, the use of stem cells to cure diabetes will be
a possibility in our near future.
Reference:
1. Soria, B., Skoudy, A., and Martin, F. 2001. From stem cells to beta cells: new
strategies in cell therapy of diabetes mellitus. Diabetologia 44 407-415
2. Raikwar, S. and Zavazava, N. 2009. Insulin producing cells derived from
embryonic stem cells: are we there yet?. Journal of Cellular Physiology, 218
256-263
3. Jiang, W., Shi, Y., Zhao, D., Chen, S., Youg, J., Zhang, J., Qing, T., Sun, X.,
Zhang, P., Ding, M., Li, D., and Deng, H. 2007. In vitro derivation of
functional insulin producing cells from human embryonic stem cells. Cell
Research. 17 333-344
8
Isolation of two storage protein promoters from Hordeum chilense and characterization of their
expression patterns in transgenic wheat
Matthew Payne - November 10, 2009
Genetic modification of plants has been a cutting edge science, which has enabled scientists to
provide farmers with plants which are disease resistant as well as plants which provide the consumer with
increased nutritional content. Cereal grains, such as wheat, are a dietary staple of humans and domestic
animals worldwide. Therefore, increasing the protein yield of such plants would greatly increase the
quality of one’s diet, stately in developing countries, or provide resistance to plant disease, primarily of
fungal origin, which affect many of these cultivated species.
In 2007 Piston, Leon, Lazzeri, and Barro published a paper describing research they had
completed which increased the knowledge of the synthesis and deposition of storage protein in cereal
grains. The researchers utilized available knowledge regarding the process of protein synthesis and
deposition of said storage protein and incorporated it into an experimental design which permitted them to
increase both the viability of plants with HMW protein production and increase their overall protein
production.
The researchers grew the plants in a greenhouse to provide 12 hour light and dark cycles. Then,
researchers isolated a 5’ UTR by genome walking (flanking genomic segments adjacent to a known
sequence). The fragment containing gusA gene and the nopaline (nos) terminator excised from plasmid
pAHC25 and inserted into pGerm3Z to create pGUS. PCR products were cloned into pGUS to create
pHorB-GUS and pHorD-GUS. Bombardment of plasmids pHorB-GUS or pHorD-GUS in combination
with pAHC20, which contains the selectable bar gene (confers tolerance to phosphinothricin) under the
control of maize ubiquitin promoter, targeted the immature scutella of wheat. Surviving explants
transferred to R regeneration medium supplemented with 2mg 1 -1 of PPT and cultured 2 additional
rounds of 3 weeks each. The putative transgenic plants were then transferred to soil and grown to
maturity in greenhouse.
The sequence of B hordein promoter reported showed structure of the prolamin promoters and
contain characteristic element ‘Prolamin box’ formed by the E motif and the N motif, whereas, the
sequence of the H. chilense D hordein promoter showed the ‘HMW-enhancer’characteristic of the HMW
gene promoters, and the G-box like and the RY-element. The fragments of the B and D hordein
promoters fused with the gusA gene to characterize their activities in bread wheat; 5 and 9 independent
transgenic lines (respectively) were obtained with plasmids pHorB-GUS and pHorD-GUS. The
expression of the gusA gene was only detected in the seeds of the transgenic lines. GUS staining
increased in both transgenic lines with the development of the endosperm, reaching max at 28 DPA when
the accumulation of the β-glucuronidase protein was maximal; staining (protein accumulation) appeared
to not be uniform in all of the endosperm. The use of QRT-PCR assisted in determining the expression
profiles of both promoters. Expression of the gusA gene first detected at 13 days post anthesis (DPA) in
both groups of transgenic plants; gusA transcripts driven by the B hordein promoter increased in level to a
peak at 25 DPA and subsequently declined, whereas gusA transcripts driven by the D hordein promoter
maintained the same transcript level from 23 to 25 DPA, and then increased expression from 25 to 28
DPA.
References needed!
9
Golden Rice: Introduce Provitamin A in Rice Endosperm
Yingying Wu-- November 10, 2009
Vitamin A deficiency can result in permanent blindness and increase the incidence and severity of infectious
diseases. It is estimated that a quarter of a million children go blind each year because of nutritional deficiency in
southern Asia. Success may be got by using recombinant technologies to produce provitamin A in a major staple
food, rice to overcome this worldwide problem. No rice cultivars produce provitamin A in endosperm, which is the
edible part of the grain. ‘Golden Rice’ is engineered to produce beta-carotene (provitamin A). The carotenoids
produced in the endosperm of the gains give rise to a characteristic yellow color.
The synthesis of beta-carotene from geranylgeranyl diphosphate that is synthesized in immature rice
endosperm requires plant enzymes: phytoene synthase, phytoene desaturase, zeta-carotene desaturase and
lycopene cyclase that is encoded by lcy gene. The original golden rice was produced in 2000, which used
Agrobacterium-mediated transformation to introduce the entire beta-carotene biosynthetic pathway into rice
endosperm with three vectors. In the single transformation, the vector pB19hpc combined the sequences for a
plant phytoene synthase (psy) originating from daffodil with the sequence coding for a bacterial phytoene
desaturase (crtI) originating from Erwinia uredovora. The psy and crt1 genes were placed under the control of an
endosperm-specific glutelin (Gt1), so that they are only expressed in the endosperm. The end product of the
engineered pathway is lycopene, but if the plant accumulates lycopene the rice would be red. Co-transformation
was using vectors pZPsC and pZLcyH. Vector pZPsC carries psy and crtI and vector pZLcyH provides lycopene cyclase from Narcissus pseudonarcissus. Lycopene -cyclase carried a functional transit peptide sequence
attached so that it is targeted to the plastid, where geranylgeranyl diphosphate formation occurs. The pB19hpc
single transformants, engineered to synthesize only lycopene (red), were similar in color to the pZPsC/pZLcyH cotransformants engineered for beta-carotene (yellow) synthesis. In fact, further research showed that lcy gene is
already being produced in wild-type rice endosperm.
Under greenhouse conditions, the original golden rice could produce 1.6 ug/g carotenoids. The Golden Rice 2,
which came out in 2005, reported has up to 37ug/g carotenoid of which 31 ug/g is beta-carotene. Golden Rice 2
produces 23 times more carotenoid than the original golden rice. Phytoene synthase is the limiting step for
carotenoid biosynthesis and is a major regulatory step. The Golden Rice 2 combines the phytoene synthase gene
from maize with crt1 from the original golden rice.
References:
Ye et al. 2000. Engineering the provitamin A (beta-carotene) biosynthetic pathway into (carotenoid-free)
rice endosperm. Science 287 (5451): 303-305 PMID 10634784
Paine et al. 2005. Improving the nutritional value of Golden Rice through increased pro-vitamin A
content. Nature Biotechnology doi:10.1038/nbt1082
10
Immune Response and Fighting Brain Cancer
Abbie Hunt-- November 10, 2009
All different types of cancer plague our medical community, but perhaps one of the most
dreaded forms of cancer is brain cancer. Glioblastoma multiforme (GBM) is one of the most dismal
forms of brain cancer, with only a 5% survival rate in a 5-y time period. In order to try and increase these
odds, Curtin et al. (2009) are studying a way to increase the brain's ability to produce an immune
response to tumor invasion which when combined with cytotoxic methods, result in tumor regression.
The immune system is often the human body's greatest weapon against disease, and exploring ways in
which to enhance this complex system to fight challenging diseases typically treated with therapies with
low therapeutic indices is an important alternative to explore.
Immune response to brain tumors is an important treatment option to consider, due to the
limited radiotherapy that can be performed on this sensitive organ and the destructive nature of the
therapy when used for cancers in other locations throughout the body. In order to study and enhance
the immune system's response to tumors, administration of adenoviral vectors, Fms-like tyrosine kinase
ligands, and thymidine kinase to mutant mice suffering from induced brain tumors was performed. This
therapy shows the specific T cells necessary for tumor regression and can actually increase the amount
of cells instrumental in the initiation of immune response, which are usually sparse in the brain and are
dependent upon signaling molecules released from dying tumor cells. These tumor cells are often dying
as a result of the established thymidine kinase and glacyclovir treatment. These signaling molecules as
well as the development of immunological memory, enable the regression of brain tumors to occur
more effectively.
A better understanding of this pathway is extremely beneficial to the fight against brain cancer
for those patients whose prognosis is grim due to a mutation in the genes that code for these signaling
molecules or their receptors. If the molecules can be administered and effective in mice, those with
aberrant receptors or molecules may benefit the most of all.
References:
1. Curtin J.F., Liu N., Candolfi M., et al. 2009. HMB1 Mediate Endogenous TLR2 Activation and Brain
Tumor
Regression. PLoS Medicine. 6(1): 84-104.
2. Southgate T., Kroeger K.M., Liu C., Lowenstein P.R. (2008). Gene transfer into meural cells in vivo
using
adenoviral vectors. Published online at Wiley Interscience. Available online at
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2659706/ Accessed 11/4/09.
3. Sandmair A., Vapalahti M., Yla-Herttuala S. (2000). Adenovirus-Mediated Herpes Simplex Thymidine Kinase
Gene Therapy for Brain Tumors. Cancer Gene Therapy: Past Achievements and Future Challenges. Plenum
Publishers, New York. 163-170.
11
Induced pluripotent stem cell lines derived from human somatic cells
Harika Nandigam- Nov 10th 2009
Somatic cell nuclear transfer is a technique for creating an ovum with a donor nucleus. This somatic cell
nuclear transfer allows trans-acting factors present in the mammalian oocyte to reprogram somatic cell
nuclei to an undifferentiated state.
Junying Yu et al showed that four factors are enough to make human somatic cells into the pluripotent
cells with all the essential characteristics of embryonic stem cells and also the potential to develop the
germ layers. Cloning of Dolly led to a search for factors that could mediate similar reprogramming
without the somatic nuclear transfer. By testing all the genes they found that OCT4, SOX2, NANOG and
LIN28 are capable of reprogramming human somatic cells with a mesenchymal phenotype. OCT4 and
SOX2 will help in the appearance of reprogrammed clones where as NANOG and LIN28 helps to
increase the number of reprogrammed clones.
To test whether these four are sufficient to reprogram primary, genetically unmodified, diploid human
fibroblasts they took IMR90 fetal fibroblasts and the human newborn foreskin fibroblasts. The induced
pluripotent human cells have the characteristics similar to that of the embryonic stem cells. Those cells
have normal karyotype, express telomerase activity, express cell surface markers and the genes that
characterize the human embryonic stem cells and also maintain the developmental potential to
differentiate into advanced derivatives of all the three germ layers.
Induced pluripotent stem cell lines can be used in different ways. This helps us to study different human
tissues, for discovering and testing new drugs. Patient specific iPS cells could be generated to treat
various diseases.
References:
Junying Yu, Maxim A. Vodyanik, Kim Smuga-Otto, Jessica Antosiewicz-Bourget, Jennifer L. Frane,
Shulan Tian, Jeff Nie, Gudrun A. Jonsdottir, Victor Ruotti, Ron Stewart, Igor I. Slukvin, James A.
Thomson. Induced Pluripotent Stem Cell Lines Derived from Human Somatic cells. Science, Vol
318(2007)
Liu shuang and Duan Enkui. Advances in the study on induced pluripotent stem cells. Chinese science
bulletin. Vol 53(2008). 709-717
12
Ca2+- independent positive inotropy for failing cardiac muscle by α-myosin motor
gene transfer
Presentation by Les Sprague, November 10, 2009
Heart failure (HF) is one of the leading causes of death in developed countries. Traditional
treatments for heart failure concentrate on increasing the presence of calcium in cardiac
muscle to improve cardiac output. This positive inotropic treatment does indeed increase
cardiac contractility. However, the long term use of calcium regulating drugs has been
linked to increased mortality by causing fatal arrhythmias. Therefore, it would be
beneficial to explore positive inotropic therapies that do not rely on the availability of
calcium within cardiac muscle.
Myosin is a motor protein which is responsible for actin based motility. Myosin and actin
are the main structural proteins of cardiac muscle. It has been shown that α-myosin
comprises ~10% of the total ventricular myosin in normal human hearts, while β-myosin
comprises the remaining 90%. The α-myosin isoform has a higher energy demand and is
the heart’s fast molecular motor. The β-myosin isoform is the slower motor.
A recombinant adenovirus (AdMYH6) was produced to deliver the human fast α-myosin
motor gene (MYH6) to rabbit and human β-myosin-dominant myocytes in vitro. By
increasing the α-myosin isoform expression, there was an increase in contractile amplitude
of failing human and failing rabbit myocytes without changing intracellular calcium
transient amplitude.
References:
"Cardiac action potential." Wikipedia. Web.
<http://en.wikipedia.org/wiki/Cardiac_action_potential>.
Freeman, Scott. Biological Sciences. 2. Upper Saddle River: Pearson Prentice Hall, 2005.
1018-1021.
Herron, Todd. "Ca2+ - independent positive molecular inotropy for failing rabbit and
human cardiac muscle by a-muosin motor gene transfer." FASEB Journal. 24.
(2009): 1-10.
"Heart failure." Wikipedia. Web. <http://en.wikipedia.org/wiki/Heart_failure>.
"Inotrope." Wikipedia. Web. <http://en.wikipedia.org/wiki/Inotropy>.
"Ischemia." Wikipedia. Web. <http://en.wikipedia.org/wiki/Ischemia>.
13
Increasing vitamin E content by overexpressing
the γ-tocopherol methyltransferase gene
Craig Schenck, November 12, 2009
Eludidating the biochemical pathways of plant nutrients in order to engineer plants for increased
nutritional value has been an area of intense research. One pathway of particular interest is the vitamin E
biosynthetic pathway. Vitamin E collectively represents a class of lipid-soluble molecules α-, β-, γ- and
δ-tocopherols and tocotrienols. α-tocopherol is considered to be the most important form of vitamin E to
humans because it has the highest activity due to its ability to be retained in humans longer than other
forms. Vitamin E has strong antioxidant properties and deficiencies cause loss of vision, muscle
weakness and loss of muscle mass. Thus, engineering a way to increase its activity (abundance?) could
greatly benefit human health.
A precursor to the active form of vitamin E, γ-tocopherol, is the most prevalent form of vitamin E
found in the seeds of soybeans, 60-65% (Tavva et al. 2007). However the activity of γ-tocopherol is
about one-tenth the activity of α-tocopherol. It is thus advantageous to be able to convert γ-tocopherol to
α-tocopherol in a more efficient way to increase the amount of α-tocopherol in the seeds of soybeans.
Overexpression of the final enzyme in the tocopherol biosynthetic pathway, γ-tocopherol
methyltransferase (γ-TMT), was shown to increase α-tocopherol content 80-fold in Arabidopsis (Shintani
and DellaPenna 1998).
α-tocopherol content was increased in two different crops soybeans and perilla. In both cases γTMT was amplified from cDNA of the seeds of Perilla frutescens. The gene was expressed under the
control of a seed specific promoter, vicilin, and a poly A coding sequence from the octopine synthase
gene, was added. In soybeans, the gene construct was inserted via particle bombardment with a gene gun.
In perilla, the gene was inserted using Agrobacterium-mediated transformation. Multiple transgenic
plants were generated and through northern blot analysis the expression pattern of γ-TMT was only seen
in immature cotyledons. High-performance liquid chromatography (HPLC) was used to quantify αtocopherol content in seeds. HPLC analysis of soybeans revealed an increase of α-tocopherol content
from 8.4% in wild-type to 85-89% in the transgenic lines. In perilla seeds, α-tocopherol content increased
from .9-11.4 mg/100 g in wild-type to 153.2-200.4 mg/100g in transgenic lines.
These two papers exhibit an innovative way of overexpressing an enzyme in a biosynthetic pathway
which can lead to increased nutritional value in agriculturally important crops.
References:
1) Tavva VK, Kim YH, Kagan IA, Dinkins RD, Kim KH, Collins GB (2007) Increased α-tocopherol
content in soybean seed overexpressing the Perilla frutescens γ-tocopherol methyltransferase gene. Plant
Cell Rep 26:61–70.
2) Lee BK, Kim SL, Kim KH, Yu SH, Lee SC, Zhang Z, Kim MS, Park HM, Lee JY (2008) Seed
specific expression of perilla γ-tocopherol methyltransferase gene increases α-tocopherol content in
transgenic perilla (Perilla frutescens). Plant Cell Tissue and Organ Culture 92:47-54.
3) Maeda H, DellaPenna D (2007) Tocopherol functions in photosynthetic organisms. Current Opinion in
Plant biology 10:260-265.
4) Department of Human Nutrition, "Vitamin E." November 2004.http://ohioline.osu.edu/hygfact/5000/5554.html (accessed 11/8/09).
5) Office of Dietary Supplements, "Vitamin E Fact Sheet." October 4,
2007.http://ods.od.nih.gov/factsheets/vitamine.asp#en4 (accessed 11/8/09).
14
Genetically modified pigs produced with a nonviral episomal vector
Alex Weber, November 12, 2009
Genetically modified organisms are nothing new to biotechnology. From the first genetically
modified bacteria to the FLAVR SAVR Tomato and Golden Rice, genetic engineering and modification
to organisms has become an invaluable and profitable technique for biomedicine and biotechnology.
Genetic modification to eukaryotes, specifically mammals, has the potential to be more beneficial than
any other type of genetic modification. The application of genetically modified mammals includes models
for human disease, bioreactors for the production of commercial products such as pharmaceuticals and the
genetic improvement of livestock to name a few. One challenge that has yet to be completely solved is an
inexpensive and effective method for introducing foreign DNA into mammals. All of the current methods
used to genetically modify mammals rely on the integration of DNA into the mammal’s genome. This
will sometimes lead to insertional mutagenesis and variable transgene expression as well as undergo
silencing. Though these methods are capable of producing genetically modified organisms that are of the
desired type, their yields are low and there is still work to be done.
When attempting to produce a new method for introducing foreign DNA into mammals, there are
three guidelines that should be followed. The genetically modified animals should have the foreign DNA
stably retained, both structurally and mitotically. The foreign DNA should not contain viral DNA
sequences or encode for viral proteins that bear the risk of cellular transformation. Also, there should be
long term expression of the introduced DNA. Prokaryotes provide a good example of such a vector
known as a plasmid. The only problem with this is that naturally occurring mammalian plasmid vectors
have never been observed. In a recent study done by Stefano Manzini et al. one such vector that follows
these guidelines is a nonviral episomal vector known as pEPI-EGFP. This vector contains what is known
as a human scaffold/matrix attachment region (S/MAR). This is a segment that allows for the vector to be
retained in the cell cytoplasm as an episome. An episome is genetic material that can replicate
independently of the host chromosome without being integrated. The S/MAR sequence is chromatin
regions that bind the nuclear matrix, and with this sequence present, it ensures episomality of the plasmid
in cultured cells, as well as preventing integration of the plasmid into the genome of the host. The study
done by Stefano Manzini et al. was done by adding a 2-Kbp S/MAR sequence to pGFP-C1 which is a
commercially available plamids. The newly created plasmid with the S/MAR sequence present was then
introduced into pigs via the sperm mediated gene transfer method. The results showed that pEPI-EGFP
was present in 12 of 18 fetuses (67%). This study shows that there is a possible method for introducing
foreign DNA into mammalian cells with high efficiency and retention as well as low levels of undesired
products. This vector system may also provide the basis for future development of germ line gene therapy.
1.
2.
3.
4.
References:
Stefano Manzini, Alessia Vargiolu, Isa M Stehle, Maria Laura Bacci, Maria Grazia Cerrito, Roberto Giovannoni, Augusta
Zannoni, Maria Rosaria Bianco, Monica Forni, Pierluigi Donini, Michele Papa, Hans J Lipps, and Marialuisa Lavitrano,
2006. “Genetically modified pigs produced with a nonviral episomal vector.” PNAS, Vol. 103, no. 47, pg. 17672-17677
Joost H. A. Martens, Matty Verlaan, Eric Kalkhoven, Josephine C. Dorsman, and Alt Zantema, 2002. “Scaffold/Matrix
Attachment Region Elements Interact with a p300-Scaffold Attachment Factor A Complex and Are Bound by Acetylated
Nucleosomes.” Molecular and Cell Biology, Vol. 22, No. 8, pg. 2598-2606
Marialuisa Lavitrano, Marco Busnelli, Maria Grazia Cerrito, Roberto Giovannoni, Stefano Manzini, and Alessia Vargiolu,
2006. “Sperm Mediated Gene Transfer.” Reproduction, Fertility and Development, Vol. 18, no. 1 and 2, pg. 19-23
“Episomes.” http://science.jrank.org/pages/2548/Episomes.html. Web. 8 November, 2009.
15
Producing Antibodies in Plants for Medical Use
Jonathan Strawser, November 12th, 2009
The demand of the pharmaceutical industry for large quantities of mammalian proteins has led
to the development of heterologous expression systems for the production of proteins and peptides.
Plant-based production is now used to synthesize foreign proteins on a commercial scale. As with all
protein production, regardless of plant or mammal, three factors must be considered. These factors
include transcription, translation, and post-translation conditions. Also, since we are dealing with
recombinant protein production in plants, environmental factors need to be considered.
In a recent study conducted by Ko et al., (2005) monoclonal antibodies (mAb) were developed to
bind a recombinant antigen associated with colorectal carcinoma cells. The study was promising
because the plant-derived mAb (mAbP) differed considerably from the mammalian-derived mAb (mAbM)
glycosylation pattern yet both were shown to be biologically similar. Cyanovirin-N is also a mAB
candidate and is used to inactivate a wide range of HIV strains that bind to gp120 but to have a global
impact proteins must be developed on a large scale and at low costs, according to Sexton et al. (2006).
This study successfully demonstrated that plants would be able to develop antibodies at a concentration
high enough to affectively bind the antigen of choice.
These two studies were both performed by transforming the plant cells of Nicotiana tabacum
with plasmid vectors. pGEM-T vector was used for colorectal carcinoma cells and pMON530 was used
for the HIV strains. Various assays ranging from western blots to ELISA were used to determine the
presence of protein within the transformed plants.
Molecular farming has many attractive features for the production of therapeutic proteins but at
the moment, is not currently satisfactory in a wide commercial scale. The plant species used and the
type of vector employed are crucial in the development of this field.
References:
1. Jamal, Kinarm Ko, Kim, Choo, Joung, Kisung Ko, 2009. “Role of genetic factors and environmental
conditions in recombinant protein production for molecular farming.” Biotechnology Advances, Vol.
27, No. 6, pg. 914-923
2. Ko, Steplewski, Glogowska, Koprowski. “Inhibition of tumor growth by plant-derived mAb.” PNAS,
Vol. 102, No. 19, pg. 7026-7030
3. Sexton, Drake, Mahmood, Harman, Shattock, Ma. “Transgenic plant production of Cyanovirin-N, an
HIV microbicide.” The FASEB Journal, Vol. 20, pg. 356-358
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Antibodies Used to Discover More about Parkinson’s Disease
Christina Ufholz, November 12, 2009
Parkinson’s disease (PD) is a neurodegenerative disease that is caused by the buildup of protein
inclusions containing α-synuclein (αS) and ubiquitin. Some rare inherited forms are caused by autosomal
dominant mutations in α-synuclein or by autosomal recessive (AR) mutations in parkin. Some motor
symptoms are bradykinesia, rigidity, resting tremor, and postural instability. Some other symptoms are
hyposmia, cognitive decline, mood disorders, pain, autonomic dysfunction and sleep disorders. About one
million Americans suffer from this disease with around sixty thousand new cases every year.
The experiment by Hideki Shimura et al. (2001) showed the functions and locations of two proteins,
α-synuclein and parkin. This study created the antibodies HP2A, HP6A, HP7A, HP8A, LB509, syn-1, and
UbcH7. Frozen brain tissue and regular brain tissue are tested and Western blotted and/or immunoblotted.
The results were a direct functional relationship in the human brain between parkin and αS that are
associated with inherited, monogenic forms of PD. Also, a multimeric ubiquitination complex was
identified. It was confirmed that neural parkin is an E3 Ub ligase and that WT parkin binds to αSp22 and
UbcH7. In vitro assays were preformed to discover the molecular effects of naturally occurring parkin
missense mutations. Future work will be needed to determine whether O-glycosylated αSp22 mediates
specific physiological functions and/or has neurotoxic effects in PD.
More recent research by van der Vegt et al. showed that the presence of a single mutant Parkin allele
does affect nigrostriatal dopaminergic function which triggers adaptive changes in motor cortical areas.
They also found that multimodal assessment of brain structure and function in non-manifesting carriers
yielded a single mutant Parkin allele and different imaging modalities provided important pieces to
resolve the puzzle of preclinical reorganization of PD.
References:
1. Berg, Daniela, Antje Bornemann, Heike Fischer, Thomas Gasser, Takafumi Hasegawa, et al. 2009.
Parkin protects mitochondrial genome integrityand supports mitochondrial DNA repair. Human
Molecular Genetics. 18(20): 3832–3850
2. Bloem, B.R., C. Klein, H.R. Siebner, J.P.M. van der Vegt, and B.F.L. van Nuenen. 2009. Imaging the
impact of genes on Parkinson's disease. Neuroscience. 164(1): 191-204
3. Farrer, Matthew James. 2006. Genetics of Parkinson disease: paradigm shifts and future prospects.
Nature Reviews Genetics. 7: 306-318
4. Frosch, Matthew P., Nobutaka Hattori, Kenneth S. Kosik, Yoshikuni Mizuno, Michael G.
Schlossmacher, et al. 2001. Ubiquitination of a New Form of alpha -Synuclein by Parkin from Human
Brain: Implications for Parkinson's Disease. Science. 293(5528): 263 – 269
5. The National Parkinson Foundation. 2007. cited: November 8, 2009
http://www.parkinson.org/Page.aspx?pid=225
17
Genetic and Genomic approaches to Improving Biofuel: Sweet Sorghum
Donny Sparrow November 12, 2009
Petroleum supplies the largest fraction of the world’s energy, coming to a total of 37 %. Petroleum is a
non-renewable resource and it is imperative that we replace our dependency on it for economic and
environmental reasons. Ethanol is an excellent fuel for internal combustion and has a high sustainability
rate. It has been proven as a good competitor for petroleum in the United States and especially in Brazil. It
has a high heat of vaporization, is a more efficient fuel, is less volatile than gasoline, and has less
photochemical activity making the emissions less potent. It also has another incentive to gasoline. Ethanol
is renewable as it is made from the fermentation of sugars harvested from plant material. Sweet Sorghum
is a relative of sugarcane and also accumulates sugar. It has a potential economic advantage, as it is
possible to ferment the hydrolized sugar and sorghum bargasse to produce ethanol and then burn the
lignin residuals as heat and electricity. 7682 L of ethanol can be produced per hectare can be produced by
sweet sorghum under good conditions. Sweet sorghum belongs to the grass family and has high
photosynthetic efficiency. It is also considered to be one of the most drought resistant plants. It can be a
perennial or annual depending on the strain. Because of its high potential as a ethanol producing crop
research has been done to maximize the efficiency of the plants sugar and cellulose production
capabilities through genetic mapping and manipulation.
References:
Dauriat, A., & Wyman, C. (2005). Refining sweet sorghum to ethanol and sugar: economic trade-offs in
the context of North China. BIORESOURCE TECHNOLOGY, 96(9), 985-1002.
Seth C. Murray, William L. Rooney, Martha T. Hamblin, Sharon E. Mitchell, and Stephen
Kresovich (2009). Sweet Sorghum Genetic Diversity and Association Mapping for Brix and
HeightPlant Gen. March 2009 2:48-62; doi:10.3835/plantgenome2008.10.0011
Jordan, D., Chapman, S., Godwin, I., Mace, E., & McIntyre, C. (2008). Identification of QTL for sugarrelated traits in a sweet x grain sorghum (Sorghum bicolor L. Moench) recombinant inbred
population. MOLECULAR BREEDING, 22(3), 367-384.
Dolat, A., Steinberger, Y., Wang, X., Osman, A., & Xie, G. (2009). Biomass yield and changes in
chemical composition of sweet sorghum cultivars grown for biofuel. Field Crops Research, 111(12), 55-64.
18