i
a
chainre ct on. 5
Brave new world:
Stories of Science and Learning from Arizona State University
Biotechnology
Will your next fillup be
Green Gunk?
Germ vs. Germ:
The Salmonella Smoothie
We're all in the tree
Amino acids. Cells. Genes. Deoxyribonucleic acid. Mitochondria. Ribosomes.
Plasma membranes. Heredity. Nucleotides. Codons. Plasmids. Double helix.
Biofuel. Bioreactors. Proteins. Messenger RNA. Enzymes. Peptide bonds.
Recombinant DNA. What do all these terms mean? They are all important
within the new world of...
Chain Reaction:
A series of chemical
reactions in which
the products of each
reaction activate
additional molecules
of the reactants, thus
causing new reactions…
C o n t e n t s
Biotechnology!
02. Green Gunk
08. Catalyst: What is DNA?
Sequencing on a Budget
12. Shaking the Tree of Life
18. Special Delivery
26. Sensing Danger
28. Crosslink: Who Owns Your Genes?
Summer Vacation
chainreaction.5
Volume 5, Number 1/2008
Welcome to a brand new era of human existence on Planet Earth.
Chain Reaction Magazine is produced by the
Office of Research Publications and published
by the Vice President for Research and
Economic Affairs at Arizona State University.
In this era, everything is faster, and everything changes quicker
The publication of Chain Reaction
is not financed by state appropriated funds.
Persons or publications wishing to reprint
articles, illustrations, or photographs
carried in Chain Reaction should contact
the editor. Clippings of published excerpts
are appreciated.
Correspondence regarding editorial
content should be sent to the editor at:
Chain Reaction Magazine
ASU Research Publications
Box 873803
Tempe, AZ 85287–3803
Tel: 480.965.1266
Fax: 480.965.9684
E-mail: [email protected]
Editor: Conrad J. Storad
Art Director: Michael Hagelberg
Managing Editor: Diane Boudreau
Managing Editor: Sheilah Britton
Contributing Writers: Diane Boudreau,
Joe Caspermeyer, Linley Erin Hall,
Conrad J. Storad
Contributing Photographers:
John C. Phillips, Michael Hagelberg
Chain Reaction Magazine is
printed on recycled content paper.
C
than ever. We live in a world of instant communication where
information flashes around the globe at light speed. It is also
a time where rapid technological change is occurring in entirely
new areas, including medicine and biology on the molecular level.
Scientists refer to this work as biotechnology. British author
Aldous Huxley wrote about bits and pieces of our time almost
80 years ago in his novel Brave New World. Arizona author
Edward Sylvester calls our time “The Gene Age.” It is a new type
of industrial revolution. Whatever you call it, the new world
of biotechnology holds possibilities even beyond the dreams,
and nightmares, of science fiction writers. At the center of all
this whirlwind of change is a single molecule. It’s called DNA.
Read on to learn more about this amazing molecule and start
a brand new chain reaction of fun and learning.
Conrad J. Storad, Editor
http://
chainreaction
.asu.edu
REAL DNA
ASU scientist Stuart Lindsay
used an atomic force microscope to view
actual molecular strands of DNA — seen as thin greenish filaments.
Learn more on page 15.
What
?
is DNA
Deoxyribonucleic acid
is big word. It is better known
by its abbreviation — DNA.
In reality, DNA is a very small
molecule. Most people have heard
something about DNA. They know it
is important. Actually, DNA is very
important. For biologists and scientists
and scholars of many types, those three
capital letters hold the key to answering
one of the biggest questions of all: What is life?
You need a powerful microscope to actually see DNA.
It looks like two strands of thread twisted together in a long
double helix. Some DNA molecules are very long. Others
are circular. In fact, all DNA is so tiny that huge amounts of it
are found inside the cells of each and every one of us.
Some scientists say that DNA is the “master molecule” for
all life on Earth. DNA is like a blueprint. It is like a library.
DNA is the codebook for all kinds of genes. And genes are
the bits of information found inside all living things.
Genes help plants and animals and insects and fish and
birds and people to function and reproduce. Together,
DNA and genes are the raw material that scientists
use in the new world of biotechnology.
Conrad J. Storad
Whatcha’ gonna
do with that
You know algae. It’s the gunk that collects on the sides
of a fish tank when you forget to clean it. It’s the slime that
makes you slip on rocks while crossing a stream. You probably
think of algae as a nuisance, if you even bother to think
of it at all.
Milt Sommerfeld and Qiang Hu think of algae as one of
the most useful things in existence. And they think about it
every day. In fact, they have an entire laboratory dedicated
to the study of algae. The Laboratory for Algae Research &
Biotechnology (LARB) is located at Arizona State University’s
Polytechnic Campus.
“We have algae everywhere,” says Sommerfeld with a smile,
gesturing around the lab at f lasks and beakers filled with
bright green liquid. There are algae spinning in centrifuges
and algae shaking on platforms.
WHERE SOME PEOPLE SEE SLIME,
MILT SOMMERFELD AND HIS
COLLEAGUES SEE FOOD AND
FUEL. THEY ALSO SEE SOLUTIONS
TO SOME OF TODAY’S TRICKIEST
PROBLEMS. BY DIANE BOUDREAU
Algae is found
in ponds, streams,
lakes, rivers, oceans,
reservoirs, swimming pools,
fish tanks... any place there is water.
ChainReaction.5
2
There are algae growing in bubbling reactors. There are algae in
refrigerators and algae under microscopes. No murky pond scum here—
these algae are the shade of a shamrock on St. Patrick’s Day.
Where other people see slime, the ASU biologists see solutions.
They see environmentally friendly fuel. They see pollution control.
They see food. They see fertilizer. In short, they see algae as an
answer to many problems that currently stare humanity in the face.
ASU scientists study all kinds
of algae. They grow algal
cells under different
kinds of light
and conditions.
Clean and green One of those problems is agricultural wastewater.
Runoff from crops and livestock contains fertilizer, pesticides,
and microbes that can pollute water supplies. People living
in rural areas often pump drinking water from private wells that
are not monitored for these chemicals.
Nitrates found in fertilizers can be dangerous to human health, especially
to babies less than six months old. When nitrate-laden water is used to mix
infant formula, it can interfere with oxygen absorption, causing “blue baby
syndrome.” The syndrome can cause brain damage and death.
Agricultural runoff also makes its way into the oceans, disturbing
the balance of marine life. Too much fertilizer in ocean water can
produce excessive growth of algae called algal blooms. These blooms
deplete oxygen, “choking” other plants and animals. Some species
of algae produce toxic blooms known as red or brown tides,
which can poison fish and mollusks.
Sommerfeld and Hu want to fight algae with algae. By running
wastewater through bioreactors that contain algae, they produce
their own algal blooms that don’t harm anything around them.
The algae gobble up nitrogen and phosphorus—two common fertilizer ingredients—leaving the water cleaner and safer than before.
The wastewater feeds the algae with the nutrients from the fertilizer.
The ASU scientists can then harvest the algae for many possible uses.
“We’re working on algae that have a purpose,” Sommerfeld explains.
“The goal is to collect the algal biomass and use it as fertilizer or animal
feed, and return the water free of nutrients.”
“Algae
are more
productive
than corn or
soybeans
because
everY
ceLL
is a factory.
”
MILTON SOMMERFELD
3
http : //c hainreac tion.a s u .edu / Biodiesel is
a cleaner alternative to
regular diesel fuel.
Diesel fuel is produced
from nonrenewable petroleum.
Fish tank to gas tank Another possible use
for all this algae is biofuel.
Imagine if you could scoop algae out of your fish
tank and put it in your gas tank. It’s not quite that easy,
but it is possible to extract usable fuel from algae.
Sommerfeld and Hu are working on a way to produce
algae-based biodiesel for cars and trucks.
Scientists around the world are working to make
alternative fuels from a variety of plant materials.
Ethanol made from corn is already widely used.
Unlike corn, however, algae aren’t food crops.
And algae don’t have to be grown on good soil that
could be used for growing food instead.
The problem with using food crops for fuel
made headlines around the world in 2007 with
the Mexican “tortilla crisis.” As world corn prices
skyrocketed, the cost of corn tortillas rose nearly
14 percent from 2006 to 2007. Low-income
Mexican families became unable to afford this
staple of their traditional diet. Economists say
the increased demand for corn-based ethanol was
the main reason for the price increases.
Biodiesel comes
from renewable sources
such as vegetable oils
or animal fats.
Biodiesel also burns
cleaner than diesel,
and it is biodegradable.
ASU scientists are also working
with the Department of Defense to develop
military jet fuel from algae.
ChainReaction.5
4
Unlike corn plants, algae can be grown in reactors on land
that isn’t suitable for farming. The algae need only water and
sunlight. Arizona has plenty of sunlight and many farms
producing nutrient-rich wastewater.
“One dairy cow produces 800 pounds of nitrogen per year,”
says Hu. “The average dairy farm has 1,000 to 2,000 cows.
We can convert 100 percent of the nitrogen they produce
into fuel. In Arizona we have plenty of waste nutrients.
Any kind of farm that produces manure—cattle, hogs, chickens—
would work.”
Algae are also extremely productive. Like all plants, algae turn
sunlight into fuel using photosynthesis. But algae do it more efficiently.
Other plants have roots and stems. Only the leaves can do photosynthesis.
With algae, however, every cell is like a leaf cell. Every cell is photosynthetic.
The researchers have nearly 40,000 known species of algae to choose
from. They look for types that are highly productive in Arizona’s climate.
So far they are working only with naturally occurring species. However,
they might consider genetic modification down the line, if necessary.
If anyone knows algae, it’s Sommerfeld. He has been studying the stuff
at ASU for more than 30 years. He is always on the lookout for species that
reproduce rapidly. “Our goal was to have organisms that could do at least
one doubling per day,” he says. His group is now working with cells that
can reproduce two to three times in a 24-hour period.
The researchers are also looking for species that produce the largest
quantities of lipids—or fats—under local conditions. Biodiesel is made
from the lipids. Growing algae in a reactor, it turns out, helps increase lipid
production. “Algae increase production of oils when they are stressed.
They grow fast in a bioreactor,” Sommerfeld says. “When they’ve used all
the nutrients they can, and can’t grow any more due to nutrient limitations,
they store chemical energy in fat. That is in contrast to humans. When
we eat too much, our bodies accumulate fat. Algae accumulate fat when
they are starved.”
Biofuel 101
Biofuel is any kind of fuel derived
from biomass. Okay, so then what
is biomass? Biomass is material that
comes from living things—plants,
animals, and their by-products.
Biofuels come from biomass that
was alive recently.
Fossil fuels also come from living
things. But unlike biofuels, these
living things died millions of years ago.
Fossil fuels are not renewable resources.
Once we run out of them, we cannot
produce more of them quickly.
Lots of different products can be
used to produce biofuel, such as
corn, soybeans, rapeseed, wheat,
sugar beet, sugar cane and palm oil.
In addition, some biodegradable
waste products can be used to make
biofuels. These include straw, wood,
manure, and food waste.
Each of these sources has its own
benefits and drawbacks. The best
sustainable energy policy is probably
one that uses several different options
instead of relying on just one.
There is a lot of interest in biofuels
today, but biofuels aren’t new.
Rudolf Diesel, the inventor of the diesel
engine, planned to run his invention
using peanut oil. Henry Ford originally
designed his Model T to run on ethanol.
However, when crude oil became
cheaply available, people lost interest
in using biofuels and started relying
on fossil fuels instead.
5
http : //c hainreac tion.a s u .edu / Everything
runs on fuel...
The 1,000-liter bioreactor seen below
can produce about 20 pounds of algae
on each cycle. When ready, the algae
needs to be harvested and dried.
The researchers run it through a
centrifuge, kind of like the bathing
suit dryers you’d find at the gym.
The centrifuge spins the water
out of the algae, leaving a paste.
The machine can process 450 gallons
of liquid per hour.
ChainReaction.5
Reacting with efficiency ASU’s Polytechnic Campus is located in
Mesa on the eastern end of the Phoenix metropolitan area. The area
is just beginning to hit its growth spurt. Set against a backdrop of the
Superstition Mountains, the campus still has a desert wilderness feel.
Roadrunners and Gambel’s quail can be seen trotting alongside students
rushing off to class. It was all this open space that lured Sommerfeld and
Hu from ASU’s main campus in Tempe. They needed space for a new lab,
and also space to build bioreactors.
Hu is the go-to guy for bioreactor design. A biologist by training,
he has always been strongly interested in engineering. Efficient bioreactor
design is crucial for producing fuel that is cheap enough to be useful
to consumers. The researchers must not use more energy to make algae
than the algae provides in biodiesel fuel. So they are working to create
the most efficient, cost-effective reactors possible.
Behind the building that houses the LARB stands a 30-foot-long bioreactor.
It can hold 1,000 liters. The tank is only a fraction of the size that a fullscale production model would be. But it allows the researchers to test
and tweak its efficiency. The reactor can produce about 20 pounds of
algae feedstock per batch. That in turn yields about 2 gallons of biodiesel—
enough to fuel a small car for 40-60 miles.
The reactors don’t require much energy, but they do need some.
For example, pumps are needed to circulate the water. In hotter weather,
the reactor also runs an evaporative cooling system.
Sommerfeld and Hu are always looking for ways to make their production
more efficient. “We know we can make diesel from algae,” explains Hu.
“The next question is—is it economical?” The pair is betting that it is.
They believe that algal-based biofuel could be ready for the market in
three to five years. If that happens, people may start thinking
a lot more highly of that slimy green gunk.
6
ASU scientists used electron beams and a computer to calculate this 3-dimensional image of the thylakoid memebrane in Synechosystis, a type of cyanobacteria. Cyanobacteria or their close relatives are the evolutionary ancestors to chloroplasts, the small photosynthetic bodies in modern plant cells.
ALGAL CELLS
bacteria
for
biofuel
Scientists all over the world
“Photosynthesis has more on its mind
other forms of biofuel as a source of cheap,
are working on ways to capture sunlight for
than making biomass for us humans,”
renewable energy. For example, in the
human energy use. Some of them are trying
explains Thomas Moore, director of
Midwest and in South America, corn is used
to develop better solar cells. Some of them
the Photosynthesis Center at ASU.
to produce a fuel called ethanol. But corn
want to imitate photosynthesis, the process
Cyanobacteria are less concerned about
might not be the best crop to use for making
plants use to take energy from the sun.
making fuel for our cars than about growing
uel. After all, if you put the corn in your gas
and reproducing for themselves.
tank, you can’t put it on your dinner plate.
Wim Vermaas doesn’t believe in reinventing
the wheel. A group of bacteria found the
“You can’t use corn twice,” says Vermaas.
But genetic engineering lets scientists
perfect way to take energy from the sun
change their priorities. For instance,
“If everyone wants to do ethanol, then
more than 2 billion years ago. He’s happy
Vermaas hopes to grow cyanobacteria
what are we displacing? Are we reducing
to let them continue doing the work.
that produce high levels of lipids, or fats.
the food supply? What are we doing to
Vermaas is a professor of life sciences at
“Lipids are good for biodiesel. We can
the soils? In the Midwest, that could be
ASU. He has studied cyanobacteria for the
modify organisms in a way that makes
farmland being used to make fuel. In South
last 20 years. “Cyan” means “blue.” These
them more productive. You don’t have to
America, the cornfields were rainforests.
bacteria got their name from their blue-
rely on Mother Nature’s design,” he says.
It’s not very sustainable. Biofuel isn’t
necessarily green.”
green color. Cyanobacteria are some of the
Biodiesel is a good option for replacing
oldest living things on Earth. They’ve been
current fuels, says Vermaas. “You can put
around for more than 2 billion years! They
biodiesel right into any existing diesel
grown on land that isn’t suitable for anything
were the first plants to use photosynthesis.
engine. You can transport it using the
else. “You can use much degraded lands,
Without photosynthesis, today’s plants
existing infrastructure,” he says.
as long as they’re sunny and reasonably
could not survive. We couldn’t survive,
either—photosynthesis produces the
oxygen we need to breathe.
Vermaas wants to grow cyanobacteria
to make fuel for human use. Right now,
the bacteria don’t make a very efficient fuel.
The beauty of bacteria is that they can be
Biodiesel releases as much carbon dioxide
warm. The water used to grow the bacteria
(CO2) as regular diesel. But it also gobbles
up CO2 when it is produced. So it doesn’t
can be reused. You can even take ground-
put extra CO2 in the atmosphere. As a result,
nitrate which will fertilize the cultures,”
it doesn’t add to global warming.
says Vermaas.
water from agricultural runoff. It contains
Scientists are looking at biodiesel and
7
http : //c hainreac tion.a s u .edu / No, really, what is
DNA?
DNA is very important stuff. But what is it, exactly?
The definition can take many forms. A science dictionary will tell you that
DNA is short for deoxyribonucleic acid. DNA is a major component of chromosomes, the structures that carry genetic information inside a living organism.
DNA can reproduce itself. It is the substance that cells and other living things
use to pass hereditary traits from one generation to the next.
That helps. But you probably want to know more.
c a t a l y s t s
make things happen.
They speed up reactions and
make some ingredients combine
that could not without them.
A biotechnology glossary:
Biotechnology is the commercialization
of biology and genetics. It is the application of new genetic technology to
practical medical and industrial problems.
Amino acids are fundamental building
blocks of proteins. There are 20 different
amino acid types. The order of amino
acids in a specific protein is determined
by the order of bases in the gene directing
the production of that protein.
Cells are the fundamental working
units of every living system. All the
instructions needed to direct their
activities are contained within DNA,
life’s master molecule.
ChainReaction.5
DNA is a molecule. To be exact, it is a nucleic acid. A biochemist will tell
you that the DNA molecule is made up of two sugar-phosphate strips.
Each strip holds chains of four chemical bases. These bases are adenine (A),
thymine (T), cytosine (C), and guanine (G).
The A, T, C, and G bases are called nucleotides. They are like chemical building
blocks. The nucleotides bond in a certain order. A will bond only with T.
C bonds only with G. The nucleotides bond to join the strips into a long twisted
double strand. Scientists call this shape a double helix.
A simple gene is made of about 1,000 base pairs. Humans have anywhere from
20,000 to 25,000 genes arranged into 23 chromosome pairs. A huge number
of the bases — more than 97 percent — have no known function. Scientists
call them “junk DNA.”
In the human body, the chromosomes contain a person’s unique DNA.
The chromosomes are found in the nucleus of nearly every cell. Cells are like
tiny factories. They need energy and food to survive and do their specific jobs.
DNA is genetic information. It holds the plan for making new, exact copies
of each cell.
Now consider that each twist of DNA is made of more than 3 billion
nucleotides. These are the bits of code. A normal human being has about
100 trillion cells of many kinds. Multiply 3 billion by 100 trillion and you get
the number of chemical building blocks present in an average human body
at any one time. The number is huge: 300,000,000,000,000,000,000,000.
But think of each double stranded twist of DNA in another way.
Science writer Roger Martin likes to describe it as a giant master recipe book.
Contained in this huge volume is a recipe for making every kind of protein
that each and every one of those 100 trillion cells needs to live. DNA is life’s
master molecule.
8
CHROMOSOME PAIR
DNA STRAND
Genetics 101:
BASIC CONCEPTS
TO GET YOU STARTED
Genes are the basic physical
and functional units of heredity.
Each gene is located on a particular
region of a chromosome.
Adenine, thymine, guanine,
and cytosine are nucleotides.
They are the building blocks of DNA.
Each gene has a specific ordered
sequence of these nucleotides.
CHROMOSOMES
CELL ORGANELLES
(SUCH AS MITOCHONDRIA)
Genetic information is stored in DNA.
Segments of DNA that encode proteins
or other functional products are called
genes.
CELL NUCLEUS
Gene sequences are transcribed into
messenger RNA. These intermediates
are called mRNA.
mRNA intermediates are translated
into proteins.
A will bond only with T.
C bonds only with G.
Proteins are large, complex molecules
made up of smaller subunits called
amino acids. They perform most
important functions for living things.
Proteins make up the structure of cells
and perform many functions within
them.
A
G
Human chromosomes photographed with
T
T
a microscope after they have been
treated with a special chemical
C
A
to make them fluoresce.
Fluorescent objects
give off light of
particular colors.
C
T
G
A
Chromatin is the complex of DNA and
protein that forms chromosomes during
cell division.
Chromosomes are threadlike structures
in the cell nucleus mainly made up of DNA.
Each chromosome contains many genes.
Enzymes are proteins that speed up
chemical reactions but are not themselves
changed by those reactions. Certain enzymes
are used in genetic engineering work to
cut and join pieces of genetic material.
Genes are regions of DNA on a chromosome.
Each gene contains the genetic code
for the production of a specific protein.
Genes make up only 2 percent of the entire
human genome. All the rest is "junk" DNA.
Genome is an organism’s complete set
of DNA. The human genome is estimated
to contain 20,000-25,000 genes.
Peptide bonds are the links that
join one amino acid with the next
in the protein chain.
Proteins are large, complex molecules
made up of smaller units called amino
acids. Proteins make up the structure
of cells and perform many functions
within them.
Proteome is the constellation of all proteins
in a cell. The proteome is dynamic.
It changes from minute to minute in
response to thousands of environmental
signals from inside and outside the cell.
Recombinant DNA (rDNA) technology
is the methods and techniques used to
remove DNA from one organism and combine
it with the DNA of another organism.
Following the instructions on the foreign
DNA, organisms such as bacteria and
yeasts can produce substances that they
are normally unable to make.
9
http : //c hainreac tion.a s u .edu / DNA
seQuencinG
on a BudgeT
By Joe Caspermeyer
DNA sequencing makes it possible for
researchers to discover the sequence of genetic
bases in a sample. The end result is shown here.
DNA sequencing instruments produce
images in which each color represents
one of the four base chemicals that
make up DNA: A, G, C and T.
Photo courtesy NSF
Thought question:
[How much
would it cost
to sequence 3 billion
base pairs at
a dollar per base?
How much
would it cost
at a penny
per base?]
In one method to sequence DNA, scientists use
chemicals called restriction enzymes to cut up
DNA strands into small pieces. Each cut occurs
at a particular base. The pieces are many different
lengths. Researchers place pieces in a thin gel
and apply electric charge to make the pieces
move through the gel. Smaller pieces move
faster. Researchers then add dyes to show
the position of same size pieces that end with
the same base (above).
ChainReaction.5
Want a blueprint of your own personal DNA, including every gene
in your body? The good news is that scientists know how to make one,
thanks to the Human Genome Project. That bad news is that you probably
can’t afford it, unless you have $10 million sitting around in your piggy bank.
DNA testing is transforming health care, but today’s tests can only
look for one or a few genes. But there are more than 20,000 genes
in the human body. If doctors could look at your whole genome—
all the information in your DNA—they might be able to provide more
individualized care. They could specially tailor treatment and prevention
programs for common diseases such as cancer, heart disease and diabetes.
The cost of DNA sequencing has already dropped a lot—from about
a dollar per DNA base to a penny. But a human being has three billion base pairs.
Even a penny a pair is far too expensive.
Researchers at Arizona State University are trying to cut the price tag
of genetic sequencing from about $10 million dollars per person to $1,000
or less. They are also trying to make the process about 10,000 times faster,
so that it can be done in days rather than over the course of years.
“If you want to develop a technology to sequence an individual
genome for $1,000, you have to think about using nanotechnology,”
says Peiming Zhang, a chemist at ASU’s Biodesign Institute.  “The technology
is available now to pioneer a new approach to sequencing.” Nanotechnology
involves working with materials on an extremely small scale—so small
they can’t be seen with the naked eye.
Zhang’s goal is to allow scientists to sequence billions of base pairs of DNA
in a single day. By increasing the speed of sequencing and reducing its cost,
genetic research may start to play a bigger role in everyday medical practice. 
In Zhang’s project, billions of base pairs of DNA could be sequenced on
a single, cookie crumb-sized chip, like a computer chip. Scientists sequence
the DNA by applying a sample of it to single-stranded DNA probes attached
to a chip. An atomic force microscope then scans the surface of the chip
to see where DNA from the sample has attached to the probes.
Jian Gu, co-leader of the project, has developed nanoprinting techniques
that will let the researchers increase the number of probes they can fit on
a chip. “Right now, we have a mechanical printing technology that could
put down billions of probes on a chip surface at very low cost,” says Gu. 
Zhang and Gu’s research is paid for by the National Institutes of Health
(NIH). Two other ASU research teams, led by Stuart Lindsay and Peter
Williams, have also received NIH funding to try to make DNA sequencing
faster and cheaper.
Williams is a professor of chemistry. His goal is to sequence genes
that are involved in disease. He wants to do this in a matter of hours,
for just a few hundred dollars.
10
Proteins fold up into complex shapes because small electrical attraction forces pull between the amino acids that make up the protein chain.
The chain tangles up in a specific way determined by the attractions. Scientists can figure out the shapes of proteins using a technique
called x-ray crystallography. With a lot of calculation, they can create a diagram of the protein structure like this one>
Lindsay, an ASU physicist, is threading DNA through a molecular ring.
The ring is actually a sugar called cyclodextrin. It can “read” the DNA
sequence by measuring differences in friction as the DNA is pulled
through it.
All of the scientists are trying to reach the same type of goal
by approaching it from different angles. If they are successful,
maybe someday your doctor will be able to treat your
health based on your unique genetic makeup.
eas
ndr
er
Bau
A
i by
am
Orig
Origami is the art of folding paper
into shapes like animals or flowers.
Some origami artists like to challenge
themselves by folding models so tiny
they could fit on your fingertip. But even
those models are huge compared to
Stuart Lindsay’s creations.
Lindsay is a biochemist at ASU. He makes
origami with DNA. DNA is what holds your
body’s genetic information. It exists in every
cell of every living thing. DNA tells your cells
when to reproduce and how to do their jobs.
Normally, DNA comes in long strands.
But Lindsay bends it into all kinds of
different shapes.
A scientist at the California Institute
of Technology first invented DNA origami.
Since then, other scientists like Lindsay
have been using and modifying the process
to fit their own research needs.
Clearly, DNA is much too tiny to fold
by hand. Instead, scientists design their
shapes on a computer, and then use
chemistry to do the folding.
The main part of the origami is a long
strand of DNA. For instance, the DNA for
DNA ORigAMi
Making shapes out of DNA isn’t just for fun.
The bits that stick out can be used to attach
other substances to the DNA. In this way,
DNA origami can be used for countless
purposes.
Lindsay is using it to attach silver particles
to the DNA. He is trying to create a complex
antenna system. He wants to mimic the process
that plants use when they capture sunlight.
Normally when we think of antennas,
we think about things like TVs and radios.
But plants have antennas too—antennas that
catch sunlight. These antennas are molecules
of chlorophyll—the stuff that makes plants
green. Chlorophyll focuses, transfers, and
absorbs light energy from the sun. It sends
the energy to reaction centers that turn
sunlight and water into fuel that the plant
can use. If scientists can figure out how to
imitate this process, we will have a clean
and renewable way to produce energy.
“There are other molecular solar cells
in existence but they aren’t very efficient,”
Lindsay explains. “We’re proposing to make
nanoscale antennas to collect and focus
light more efficiently.” Diane Boudreau
a virus called M13 is made up of 7,000 DNA
bases in a single strand. Lindsay makes
folds in the long strand by using smaller
pieces of DNA to pull two parts of the strand
together in specific places. The small pieces
of DNA “staple” the parts together.
“You bend the DNA by using short bits of
DNA with ‘sticky’ ends to fasten two sections
together,” Lindsay explains. “You pick out
where to link two strands together and then
find the DNA that will connect there. Out from
your computer comes a little ordering list,
saying, ‘You need these bits of DNA.’”
After that, he puts the strand of DNA in
solution with the sticky bits, heats it all up,
cools it down again and—voilá!—custom
DNA shapes.
“It’s an unbelievable process,” says Lindsay.
“What’s marvelous is you can make selfassembling structures of DNA that have
single strands poking out, like a tether line.”
In fact, Lindsay and ASU chemist Hao Yan
created the first DNA arrangement with strands
sticking out at specific locations. As an
example, they created an array that spells
out “ASU” using protruding DNA loops.
11
http : //c hainreac tion.a s u .edu / ShTree
Aking
of
THE
Life
By
Joe Caspermeyer
Click, click, clack. Click, click, clack.
Click, click, clack.The sound pours
through the doorway. Click, click, clack.
Welcome to Sudhir Kumar’s laboratory. Step inside. Be prepared
for a shock. The familiar sights and sounds of modern research— clanking test tubes, technicians in white lab coats, winking LED displays— are nowhere to be found.
Click, click, clack. The rhythmic tapping is the sound of scientists
pounding away on computer keyboards. The keyboards are connected
to a large bank of networked computers. It is the vital piece of technology
that sustains Kumar and his team as they work to solve some of
the greatest unanswered questions in biology.
How and when did life on Earth evolve?
How can scientists identify the genes involved
in diseases such as cancer?
How does an organism develop from a tiny, fertilized egg
into an adult body made up of trillions of cells?
Kumar is director of the Center for Evolutionary Functional Genomics
(EFG) at Arizona State University. Kumar and his research team are using
new methods and tools to uproot the conventional scientific wisdom
of biology. In the process, they are giving the tree of life a good shaking.
Kumar has training in genetics, evolutionary biology, and electrical
engineering. He uses a new branch of science called bioinformatics as
a tool to find answers to big questions.
Kumar defines bioinformatics as “any type of information processing
that relates to biology.” Using bioinformatics requires a deep understanding
of biology, computer science, and statistics.
Bioinformatics is a totally new way of studying biology. Kumar does
not do lab experiments using live organisms (in vivo). He does not grow
cultures in test tubes (in vitro). He does his work using only the silicon
power of computer microprocessors. This type of work has been dubbed
science in silico.
Working in a lab is often necessary, but it has some drawbacks.
Labs require specialized equipment. And living specimens require
a high level of care and maintenance.
ChainReaction.5
12
Modern humans (Homo sapiens) spread out of Africa, 0.1 million years ago
< < T I M E BE F O RE P RE S E N T I N M I L L I O N S O F Y E A RS
1
2
3
4
5
6
7
8
9
< fossil time
molecular time >
Humans vs. orangutans (Pongo), 11.3
Humans vs. gibbons (Hylobates), 14.9
Cattle (Bos) vs. sheep (Ovis) and goats (Capra), 19.6
Cattle vs. deer (Cervus), 22.8
Hominoid primates (Homo) vs. Old World monkeys (Papio, Macaca), 23.3
Chickens (Gallus) vs. quail (Coturnix), 39
Mice (Mus) vs. rats (Rattus), 41
ASU scientists use
a molecular clock to
tell evolutionary time.
Cattle (Bos) vs. pigs (Sus), 65
On this illustration,
Murine rodents (Mus, Rattus) vs. hamsters (Cricetulus), 66
the timescale is measured
Cattle versus Carnivores (Felis, Canis) vs. horses (Equus), 84
in millions of years before
Primates vs. tree shrews (Tupaia), 86
the present. The results show
how times told by the fossil record
Chickens or turkeys (Meleagris) vs. ducks (Anas), 90
and by the molecular clock method
Primates vs. cattle (Bos), 90
are in close agreement. For example,
Primates vs. rabbits (Oryctolagus), 90
look at the bottom of the illustration.
Chicken (Gallus) vs. pigeon (Columba), 104
At left, fossils tell us that life first
Primates vs. elephants (Loxodonta), 108
existed on the Earth about 4 billion
years ago. The number 4 billion
Murine rodents (Mus, Rattus) vs. guinea pigs (Cavia), 109
is equal to 4,000 million.
Primates vs. rodents (Mus, Rattus), 110
At the right, the molecular clock
Chicken (Gallus) vs. ostrich (Struthio), 119
says that early life on Earth
Placental mammals (Homo) vs. marsupials (Didelphis), 173
showed up about 3,970 million
Turtles vs. crocodilians, 207
years ago. That is the same
as 3.97 billion years.
Birds (Gallus) vs. closest living reptiles (crocodilian, turtle), 228
Pretty close.
Squamates (lizards, snakes) vs. birds (Gallus) and other reptiles, 245
Now you give it a try
Living reptiles vs. mammals (calibration), 310
with some of the other
Amniotes (reptiles and mammals) vs. amphibians (Xenopus), 360
examples on the list.
Old World monkeys vs. New World monkeys (Ateles, Saimiri), 48
30
cenozoic
40
70
80
200
mesozoic
90
100
Tetrapods (amniotes, amphibians) vs. ray-finned fishes (Danio, Fugu), 450
Plectomycete fungi (Aspergillus) vs. pyrenomycete fungi (Neurospora), 468
300
500
Lampreys (Petromyzon) vs. hagfishes (Myxine), 499
Tetrapods and bony fishes vs. cartilaginous fishes (sharks, rays), 528
paleozoic
400
A new way
to tell time
Cats (Felis) vs. dogs (Canis), 46
20
60
Humans vs. chimpanzees (Pan), 5.4
Humans vs. gorillas (Gorilla), 6.4
10
50
Modern humans vs. neanderthals (H. neanderthalensis), 0.465
Pathogenic yeast (Candida) vs. bakers' yeast (Saccharomyces), 546
Jawed vertebrates vs. jawless vertebrates (Petromyzon), 564
Vascular plants (Arabidopsis) vs. mosses (Physcomitrella), 600
600
Vertebrates vs. cephalochordates (Branchiostoma), 751
Hemiascomycetan fungi (Saccharomyces) vs. filamentous ascomycetan fungi (Aspergillus), 950
700
Fission yeast (Shizosaccharomyces) vs. bakers' yeast (Saccharomyces), 984
800
Ascomycotan and basidiomycotan fungi vs. mucoralean fungi, 997
archaean proterozoic
900
Vertebrates vs. arthropods (Drosophila), 993
Land plants (Arabidopsis) vs. chlorophytan green algae (Chlamydomonas), 1100
Ascomycotan fungi vs. basidiomycotan fungi, 1117
1000
Vertebrates vs. nematodes (Caenorhabditis), 1177
2000
Animals vs. plants versus fungi, 1576
Origin of mitochondria, 1840
3000
Diplomonad protists (Giardia) vs. other eukaryotes, 2230
Cyanobacteria (Synechocystis) vs. other eubacteria (Escherichia), 2560
hadean
4000
5000
Origin of eukaryotes, 2730
Presence of early life on Earth, 3970?
13
http : //c hainreac tion.a s u .edu / Kumar’s group enjoys much more f lexibility. They can take on many
different questions that involve different organisms at the same time.
He mines data banks for information to help answer his questions.
“That data usually exists in huge amounts. It almost always requires us
to develop new analytical methods and tools,” he says.
“Data mining” got its name because it’s a bit like mining for gold.
But the chinking sound of pickaxes on rock has been replaced by the
crunching of raw data on computers. The valuable nuggets are not gold
or silver, but useful information. The information is buried in national
databases such as GenBank. GenBank contains more than 23 million
DNA sequence records deposited over the years by scientists from
around the world. The gemstones waiting to be found and understood
are part of the immense streams of DNA sequence data.
Molecular Clocks Kumar does not shy away from the tough questions.
For instance, he has asked exactly when modern mammals first burst
onto the evolutionary scene. The fossil record suggests that mammals
emerged about 65 million years ago. Scientists refer to this period
as the K/T boundary. K/T refers to a mineral layer deposited in rocks
between the Cretaceous (K) and Tertiary (T) geologic periods.
Because scientists know when this layer was formed, they know
the ages of fossils found in the layer. It was during this time when mass
extinctions spelled doom for 75 percent of all life on Earth. It was
also the end of the Age of Dinosaurs.
But the fossil record for early mammals was incomplete. It showed
that mammals existed during the K/T boundary, but not whether
they existed before that. To address his question, Kumar needed
a new kind of watch, a new way to tell evolutionary time.
The ASU scientist built himself a “molecular clock” to study
the problem. The molecules that make up Kumar’s clock are DNA.
DNA is the chemical blueprint for life found in every cell
in every living thing.
All the DNA information contained in an organism is called
a genome. By comparing the DNA sequences from the genomes
of different organisms, Kumar devised a new way to tell time.
“Copies of the genome are being made continuously and
passed on through each new generation. Over time, mutations,
or errors, are always occurring within a genome,” he explains.
Think about it in terms of a photocopier. The machine
does not always work perfectly. In much the same way,
the cellular machinery needed to copy a genome can jam
and break down. On a photocopy, mistakes show up
Studying the evolutionary
history of life on Earth is
a very tough task. Building
an accurate tree of life is
one of the biggest challenges
for biologists. At Sudhir Kumar’s
ASU laboratory, a long computer
printout is taped to one of
the walls. It stretches along the
wall from the floor to the ceiling.
The printout is a list. It lists
the major classifications of
all known life on this planet.
ChainReaction.5
14
as streaks and smudges. On the genome,
mistakes show up as DNA mutations.
Some mutations are bad enough to kill
the organism that has them. These mutations
obviously do not get passed on. But some
mutations don’t have an effect on the organism.
These mutations do get passed on generation
after generation. “These mutations are known
to accumulate more or less linearly with time.
This is where we get the concept of
molecular clocks,” says Kumar.
Molecular clocks are not perfectly accurate.
“However, these clocks do provide a direct
relationship between time and evolutionary
distance,” Kumar says.
Kumar’s molecular clocks suggest that
mammals appeared on Earth between 90 million
and 110 million years ago. That is almost 30 million
years earlier than the fossil record indicates.
“Our results showed for the first time that early
mammals may have lived along with dinosaurs long
before the extinctions that occurred at the K/T boundary,”
Kumar says. “These early mammals were probably tiny
creatures, perhaps no bigger than a mouse.”
Using the new timeline, the researchers were also able to compare
the early history of mammals with the geological history of the Earth.
Our planet was a place of violent upheaval around 100 million years ago.
“The continents were breaking apart 100 million years ago, just about
the same time that mammal groups were being established,” Kumar says.
His group proposed an idea to fit the time and events. They call it
the “Continental Breakup Hypothesis.” It says that when individual animals
or large groups of mammals are stranded on an island or land mass that is split
from the main population, over a long period of time those creatures will
evolve into new species. In recent years, other scientists have supported
the predictions from this hypothesis.
“In addition to studying the fossil record, the molecular clock technique
is now commonly used by scientists,” Kumar says.
This atomic force microscope (AFM)
image shows strands of DNA — the thin
greenish filaments. Chromatin proteins
show as the lighter masses attached
to the strands. The DNA was extracted
from the promoter region of a cancercausing retroviral gene.
AFM works by drawing over a molecular
sample with an extremely fine probe.
The tip measures electrical forces
between the tip and the sample.
The information is processed to create
an image something like what you
would get by rubbing a pencil over
an image pressed into a pad of paper
from behind.
Solving Disease Riddles Evolution is just one area of study. Kumar’s group
is also using their tools to unravel the mysteries of cancer, cystic fibrosis,
and other diseases. To find answers, Kumar looks at gene sequences from
a virtual zoo of animal DNA.
15
http : //c hainreac tion.a s u .edu / Evolving
Science
Science is always changing.
Scientists don’t make one discovery
and accept it as fact. They are always
looking for evidence that supports or
contradicts what they have learned.
One way they do this is by repeating
studies that have been done before.
Scientists publish their methods
and results so that other researchers
can repeat them. If repeated studies
get the same results over and over,
we can be pretty confident that those
results are right.
Another way to test results is by
using new methods or tools to study
the same question. That is what Sudhir
Kumar is doing. Some scientists study
evolution by looking at fossils and
figuring out when they were buried.
Kumar is studying evolution by
comparing the genomes of different
animals. Using multiple methods of
study is more likely to paint an accurate
picture of evolution than just using one.
One of those animals is the puffer fish. Japanese sushi chefs use
the puffer fish to prepare a dish known as fugu. However, if fugu is prepared
incorrectly, the chef can kill his customers. One puffer fish contains
enough deadly toxin to poison all the guests in the restaurant.
When Kumar started using the DNA of puffer fish and other organisms
to help identify genetic mutations, he caught the attention of Jeffrey Trent.
Trent is the director of the Translational Genomics Research Institute (TGen)
in downtown Phoenix. Kumar’s work was key to the successful completion
of the Human Genome Project. The project was a massive international
effort to sequence the three billion chemical letters of DNA that make
up our human genome. The sequencing work was finished in April 2003,
exactly 50 years after scientists James Watson and Francis Crick solved
the elegant spiral structure of the DNA molecule.
Scientists at TGen use genome science as a tool to solve the medical
riddles of cancer. They want to transform the idea of cancer as an acute
life-threatening disease into one that is more a manageable, chronic disease.
“Cancer is really 212 different diseases,” Trent says. “We are giving
Kumar specific intervals within the human genome where we think there
are likely to be genes for certain key diseases. His group will then use
their tools to help us identify those genes.
The Science Behind Sequence Comparisons
Sudhir Kumar likes to draw trees of life.
He’s been drawing them since the early 1990s.
Computers make the job easier. But in the
early days, Kumar could not find a reliable
computer program to help with his drawing.
The ASU biologist refused to give up.
He solved the problem by starting from
scratch and writing his own program.
The result was Molecular Evolutionary
and Genetic Analysis (MEGA).
Using MEGA, scientists can compare the
sequence of chemical letters that make up
the DNA alphabet. They can quickly compare
sequences from different species such as
fish, birds, and humans to pinpoint changes
in either the DNA or protein alphabet.
The DNA alphabet includes only four
letters: C, T, G, and A. These refer to DNA’s
four chemical building blocks: cytosine,
thymine, guanine, and adenine. Think of
different combinations of these as words,
sentences, paragraphs, or entire volumes
of information. All of this information can
be duplicated and passed along.
The real tree of life looks like
the figure in the background—
many branches develop from
earlier forms of life. Many
branches develop even more
branches, but not all branches
exist today.
ChainReaction.5
16
Each DNA “letter” is made up of a block of
three bases. Each 3-base code corresponds
to part of a protein known as an amino acid.
The protein alphabet contains 20 different
letters. The letters specify amino acids in
a specific order. They link into thousands
of different kinds of proteins to perform
countless different functions in our bodies.  
Changes in the DNA alphabet will change
the meaning of the amino acid “letters.”
This in turn changes the meaning of
the protein “word.” In this example, notice
that there is only a single letter difference
in the DNA sequence of a bird compared
to that of a fish (orange), while there are two
changes in the human sequence compared
to that of the fish (orange and blue).
Using this example, one can see that
birds are more closely related to fish
than humans are to fish.
Scientists use the MEGA program
to quickly fetch a DNA sequence stored
in the database. The program then compares
and aligns that specific sequence with
any number of other sequences. Scientists
use the results to draw an evolutionary tree.
ASU’s Sudhir Kumar has been drawing
phylogenetic trees since the early 1990s.
When he started, Kumar could not find
a reliable computer program to help
with his drawing. He had to develop his
own program. Molecular Evolutionary
and Genetic Analysis (MEGA) was
developed and released as a tool for
the scientific community in 1994. Today,
updated versions of MEGA allow anyone
to become an armchair evolutionary
biologist and study the history of life
on Earth. This image shows how MEGA
represents the relationship of different
species based on DNA comparisons.
Then we can test the genes at TGen,” he explains.
The ASU scientists take these genome intervals
and compare them with similar intervals from other
animals such as puffer fish, chickens, mice, and cows.
By studying the same gene across different species over time,
Kumar can figure out which sequences are the most conserved—
in other words, which sequences do not change.
Kumar has found that the most conserved DNA letters within a protein
over evolutionary time are the most vital towards that gene functioning
properly. Why? Because mutations that cause disease are found most
often in these positions.
Throughout the course of evolution, nature holds onto the most important
DNA information and discards the rest. By identifying the changes in the
letters, Kumar’s group can now assist the scientists at TGen in choosing
new directions for their experimental work.
In the future, the ASU researchers plan to remain f lexible enough
to continue making discoveries in a wide range of areas such as cancer
research, evolution, developmental biology, and software development.
“In every sense, development and evolution are intertwined. I think of it
as all one project,” he explains. “I’ve always liked evolution because so much
remains unknown and it is so challenging to infer history. I want to immerse
myself in many different areas and learn to see the interconnections.”
Start with a hypothetical fish DNA base sequence: tttgatgataat
This chemically "reads" in three-letter blocks called codons:
tttgatgataat
Each codon specifies an amino acid to build a “protein word:” Next, compare it to a bird DNA sequence:
...that aligns amino acids: Then compare it to human DNA:
...with the resulting amino acids: F E E D
Fish "protein word”
tctgatgataat
S E E D
Bird "protein word”
tctgatgataaa
S E E 17
K
Human “protein word”
http : //c hainreac tion.a s u .edu / special
elivery
D
BY DIANE BOUDREAU
Pinch! Smallpox immunization
required a sharp needle to poke
a tiny bit of weakened virus
under the skin.
ChainReaction.5
“The Speckled Monster”—it sounds like something children imagine
lurking under their beds. Or maybe it’s the sort of creature that eats
New York in a bad horror movie. In reality, the speckled monster
was Edward Jenner’s name for smallpox, a disease caused
by a virus. Up until the last century, smallpox was a very
real threat to children and adults alike.
Jenner was a doctor in the late 1700s. In those days
smallpox killed 10 percent of the population. It caused one-third
of all deaths among children.
Jenner noticed that milkmaids who were exposed to another virus—
cowpox—did not catch smallpox, even when they were exposed to it.
Cowpox is a virus that infects cows. It is similar to smallpox, but it is
much less dangerous to humans.
Jenner formed a hypothesis. He believed that catching cowpox made
people immune to the deadly smallpox virus. To test this, he infected people
with cowpox and then exposed them to smallpox.
They did not get sick.
Jenner’s discovery led to the first widespread
vaccination program. Today, smallpox has been
eliminated. There are samples of the virus in
laboratories, but nobody catches the disease
naturally anymore, thanks to the vaccine.
Vaccines work by preparing your immune
system to fight. Your immune system is like
an army that defends your body from invaders.
When it detects an intruder—like the chicken
pox virus, for instance—it launches an attack.
Your immune system makes antibodies that are
specially designed to destroy chicken pox. After
the virus is gone, the antibodies stay in your body.
If you ever come in contact with chicken pox again,
your body is ready to destroy it quickly and easily.
When you get a vaccine, your immune system thinks
it is facing a real enemy. It produces the same antibodies
it would make if you had a disease. But with a vaccine, you don’t
have the pain and risk of getting sick.
Jenner was lucky to find a virus that was like smallpox to use in his
vaccine. For other diseases, scientists make vaccines using germs that have
been killed or weakened so that they don’t cause illness.
Once in a while, even the dead or weakened viruses can make people
sick. In the 1980s, scientists found a way around this problem using genetic
engineering. They created “subunit” vaccines, which use only part of
18
a virus instead of the whole thing. They leave out the parts that make
you sick. Most vaccines used today are subunit vaccines.
Here in the United States, most children are vaccinated at a young age.
We don’t worry much about dangerous diseases like diphtheria, mumps
and polio.
In poorer countries, however, these diseases are still a serious threat.
The World Health Organization says that in 2002, about 2.1 million people
died from diseases that could have been prevented by vaccines.
The most obvious reason for this is that people in poor countries can’t
afford vaccines. Also, traditional vaccines must be refrigerated
until they are used, and trained healthcare workers must
give them out. In rural areas, where people live far
apart and doctors are scarce, vaccines can be
difficult to store, transport and dispense.
Another problem is that vaccines
don’t exist for some of the diseases that are common in poorer countries.
The biggest drug companies are based in wealthy countries
like the U.S. They tend to focus their vaccine research
on diseases that happen where they live.
Researchers at ASU are trying to develop new
and better vaccines. Some are trying to develop
vaccines for diseases we haven’t been able
to prevent before. Others are working to make
existing vaccines safer, cheaper, and more
efficient. This will make them easier to deliver
to less-developed countries, as well.
These scientists have to find creative new
ways to produce and deliver vaccines. They are
not afraid of trying ideas that might seem bizarre—
like putting vaccines into tomato plants or Salmonella bacteria.
Read on to find out more.
[A hypothesis is
an educated guess
that explains how or
why things happen.
Scientists use
experiments to test
their hypotheses.]
[THOUGHT QUESTION]
Jenner’s experiment saved millions of lives.
But he took a huge risk by exposing people to smallpox
without knowing if they were really immune to it. Today, scientists
cannot expose people to deadly diseases in their experiments.
But in order to make new vaccines, they do have to test them.
How can scientists find out if a vaccine will really work against
a deadly disease without putting their test subjects in danger?
19
The word
“vaccine”
comes from
“vacca,”
the Latin word
for “cow.”
The first vaccine,
invented by
Edward Jenner,
used a virus
found in cows.
http : //c hainreac tion.a s u .edu / Veggie
Vaccines
Growing Genes How do you get
a vaccine into a tomato? To turn
a vegetable into a drug, scientists
take a gene from the virus that causes
a disease and insert it into plant cells.
The cells adopt the gene into their
own DNA and pass it on when
they reproduce.
One way to get a gene into a plant
cell is by using a “gene gun.” Scientists
load genes onto microscopic gold
particles. They accelerate the particles
and shoot them into the plant cell.
As the particles pass through the cell,
some of the viral DNA is left behind
to mix with the cell’s DNA.
ChainReaction.5
Great ideas come in the strangest packages. For Charles Arntzen,
inspiration struck in the form of a banana. This “eureka moment,”
as he calls it, happened while he was traveling through Thailand in 1991.
“I had a weekend off and went to the f loating market north of
Bangkok,” recalls the ASU plant biologist. “There was an old lady with
a boat full of bananas. A mother came along and bought a bunch. She had
a child in her arms that started to cry. The mother took out a sweet,
ripe banana, rubbed it on her finger, and stuck it in the kid’s mouth.”
A year earlier, the Children’s Vaccine Initiative asked scientists to develop
new ways of making and delivering vaccines. Arntzen had been thinking
about that challenge during his trip. The woman in the market gave him an
idea. “I thought, ‘Gee, if we put genes for vaccines in bananas, every mother
in Thailand knows how to get it in their kid’s mouth!’” he says.
Arntzen and his research team have been working to grow vaccines in
food crops ever since. He is working on vaccines for cholera and hepatitis
B, among other diseases.
Making vaccines you can eat isn’t really as easy as feeding a child
a banana, however. First, the researchers need to make sure the vaccines
will not be destroyed by stomach acid before having a chance to work.
And they have to be sure that the vaccine will attract the attention of
the immune system. “How do we put the gene in? How do we improve
the gene? How do we get the gene in the fruit as opposed to the root
or the leaves?” Arntzen asks. These are all questions he must answer.
Although his inspiration came in the form of a banana, Arntzen has
been working with tomato plants to make his vaccines. But tomatoes—
or any other fruits—come in different sizes.
““I started out with a rather naïve view that we would simply harvest,
say, a banana,” says Arntzen. “But you can't just grow a crop and put it out
into the public. You have to standardize doses and meet regulations.”
To do this, the researchers purify the fruit, removing seeds and skins.
Then they freeze-dry it, powder it, and put it into capsules.
20
Salmonella is a bacterium
that likes to hang out in raw poultry
and uncooked eggs.
Plant-based vaccines are much cheaper
to make than traditional vaccines. They also do not
need to be refrigerated. As a result, developing countries
can produce and distribute the products on their own without
relying on drug companies in Europe or the United States.
“You don’t have to build a big, expensive factory to do
what we do,” explains Richard Mahoney, a chemist who works
with Arntzen. “A modern vaccine factory costs from $80 million
to $250 million to build. For plant vaccines, you’re talking about
a greenhouse. Even if the vaccine tomatoes cost ten times the price
of regular tomatoes, it’s still just pennies a dose.”
salmonella smoothies?
Most people wouldn’t mind eating a tomato or banana in order
to get a vaccine. But Roy Curtiss is trying to convince people
to gulp down Salmonella! Salmonella is a bacterium that likes
to hang out in raw poultry and uncooked eggs. It can cause
diseases ranging from food poisoning to typhoid fever.
If Curtiss has his way, he will have children drinking liquids
laced with this nasty bug! What’s the big idea?
Curtiss is a professor of life sciences at ASU. He is also an expert
on Salmonella bacteria. Through genetic engineering, he hopes to develop
a form of Salmonella that can deliver a vaccine without causing any harm.
His latest project is to prevent infection from Streptococcus pneumonia,
the bacteria that cause pneumonia and meningitis. He also is working
on a similar vaccine for bird f lu. “Part of our goal is to develop a vaccine
that is safe for newborns or infants,” Curtiss explains. “Most people would
say, ‘you have got to be kidding me! With a bacteria like salmonella?’ Yes.
We can tame it so it will be a friend of a newborn and not cause any harm.”
Curtiss and his research team have shown that their vaccine protects
mice from dying when they are exposed to bacteria that cause pneumonia.
Salmonella has evolved ways
to survive the acid in your stomach,
the bile in your small intestine,
and the high pressure and
toxic iron in your large intestine.
21
http : //c hainreac tion.a s u .edu / Salmonella typhimurium pictured by a scanning electron microscope.
The image is color-enhanced to help
distinguish different parts. The bacteria
(red) are invading cultured human cells.
Photo: Rocky Mountain Laboratories
STOPPING
AIDS
AT
THE
GATE
ChainReaction.5
It protected them even when they were
exposed to a dose 100 times bigger than
what would normally kill them.
The current pneumonia vaccine for infants
and toddlers requires four separate shots given at
specific intervals. This makes it hard to deliver to people in lessdeveloped countries. Many of these people are spread out over large areas.
There aren’t many clinics and trained healthcare workers, so people have
to travel far to reach them. They don’t usually have cars. By providing
a single-dose oral vaccine, Curtiss hopes to make it easier for people
in poor countries to get it. In addition, current pneumonia vaccines
are expensive to produce. They cost an average of $40 per dose.
Curtiss’ vaccine would cost only about $1 per dose.
Salmonella is a successful germ because it can adapt to overcome
the body’s defenses. But the king of adapting may be HIV, the virus that
causes AIDS. Twenty-five years after the first AIDS case was reported,
there is still no cure or vaccine for this deadly infection. The virus is
a tricky target for several reasons.
With most diseases, at least some people recover fully. The survivors
are immune to future infections from the same virus. Scientists study
these survivors to figure out how their bodies fought off the disease.
Then they create a vaccine that produces the same immune response.
“In all research on vaccines from the time of Edward Jenner, one of the
key things to create immunity is to look for natural cases of immunity,”
explains Tsafrir Mor, an ASU biologist. But scientists don't have anyone
who has completely recovered from the AIDS to study.
To make matters worse, HIV attacks the immune system, the very system
that should be fighting it. Once the virus gets into a body, it hitches a ride on
the immune cells and uses them to sneak into the lymph nodes, the immune
system’s “headquarters.” HIV can hide out in the immune system for a long
time—sometimes for years—before it starts replicating and causing damage.
“The virus is making a fool of our immune systems,” says Mor.
These problems and others have slowed down attempts to develop
a vaccine against HIV. Mor is trying a new approach. He wants to cut off
HIV before it even gets started.
Most vaccines are delivered by injection. They cause the immune system
to make antibodies in the blood. These antibodies fight off viruses after
they have entered the body. Unfortunately, once HIV gets into the body,
it is almost impossible to get rid of.
22
But why did he choose Salmonella? The bacterium is actually a good
choice for delivering vaccines because it has evolved many ways to get past
the immune system. The features that make it so dangerous as a disease also
make it a perfect tool for shuttling vaccines through the digestive system.
Salmonella has evolved ways to survive the acid in your stomach,
the bile in your small intestine, and the high pressure and toxic iron in
your large intestine. After getting through that obstacle course of dangers,
the persistent bacteria attach to the cells that line your intestine.
They get the cells to take them up and force their entry into your body.
Curtiss and his team have found a way to delay the process through
which Salmonella causes disease. They have also designed the bacteria
to self-destruct after a certain period of time. “In the past, we
would put anywhere from two to four genetic modifications into
some of these live salmonella vaccines. The ones we make now
have 15 to 25 genetic alterations. They are very different critters.”
Epithelial cells line the outside and
inside of the body: skin is made up of
epithelial cells, as are the mucous linings
of the mouth, nose, lungs, anus, and
urinary and reproductive tracts.
Mor wants to turn HIV away at the gates. The body’s first line
of defense is its epithelial cells. These cells line the outside and
inside of the body. Your skin is made up of epithelial cells. So are
the mucous linings of your mouth, nose, lungs, anus, and urinary
and reproductive tracts.
HIV is usually spread when the virus comes in contact with those
mucous linings. Normally, these mucosal cells form a wall that won’t let
anything pass through. However, the body needs to let some molecules in.
HIV gets through this wall by passing itself off as a friendly molecule. It slips
through the body’s borders like a traveler with a fake passport. Once inside,
the virus gets busy finding host cells to infect so that it can start replicating.
The researchers want to stop the virus before it can get inside the body.
They plan to deliver their vaccine by mouth instead of through a shot.
Traditional vaccines only produce antibodies in the blood, not
the mucosal surfaces. However, when a vaccine is delivered by mouth
or inhaled through the nose, it can produce antibodies in both the blood
and the mucosal system. This kind of vaccine would block the virus from
entering the body and also neutralize it inside the body if it slips though.
So far, the scientists have tested their vaccine on mice. The mice were
able to block HIV after receiving the vaccine. The results are promising,
but there is still a long way to go. More animal trials are needed to ensure
that the vaccine is safe. Only then can it be tested on humans.
“Every minute, 10 people are infected with HIV, and five people die
of AIDS,” says Noboyuke Matoba, a researcher who works with Mor.
“We have to stop it.”
23
http : //c hainreac tion.a s u .edu / A safer
TOP: Components of a smallpox
vaccination kit including the diluent,
a vial of smallpox vaccine, and
a bifurcated needle.
ABOVE: A transmission electron
micrograph of a tissue section
containing variola viruses.
Photos: Center for Disease Control
ChainReaction.5
smallpox
It’s easy to see why scientists want to
make vaccines for diseases like HIV
and pneumonia. These illnesses kill
a lot of people. Bert Jacobs, on the
other hand, is developing a vaccine
for a disease that no one ever
catches—smallpox.
It might seem silly for a scientist
to create a vaccine for a disease that
was eliminated years ago. But after
the terrorist attacks on September 11,
2001, the United States began preparing
for any kind of terrorist activity,
including bioterrorism, or germ warfare.
Smallpox could be used as a bioterror
weapon. People today aren’t vaccinated against
smallpox, but the virus still exists in laboratories.
If a stolen lab sample was unleashed on the public,
it could sicken millions of unprotected people.
Why don’t we just use the existing smallpox vaccine—
the one that destroyed the disease to begin with? The current
smallpox vaccine is made with vaccinia, a living virus that is
related to smallpox. Unfortunately, vaccinia can make some people sick,
especially children and people with weak immune systems.
These risks are rare. But even the “normal” side effects of the vaccine
are pretty nasty. Some people develop a red welt and blistering. Some suffer
f lu-like symptoms such as fever and swollen glands.
Most vaccines used today are made with either killed viruses or parts
of viruses (known as subunit vaccines). These are safer than live vaccines.
Unfortunately, vaccinia does not work as a killed or subunit vaccine.
“So we’re stuck with a live vaccine for smallpox,” Jacobs says.
Developing a safer smallpox vaccine has become a national priority.
But vaccine development takes a long, long time. Jacobs has a head start.
He already has a good understanding of how vaccinia virus works
in the body.
When Jacobs arrived at ASU more than 20 years ago, he never
imagined that he would end up making vaccines. He certainly never
imagined his work would be considered important for national security.
He just wanted to do basic research on viruses, the kind of studies that
add to our general knowledge.
24
vaccine
“I’ve been interested in science ever since I can remember,”
says Jacobs. “I want to know how living things work.”
After studying biology in college, Jacobs chose to focus on the interferon
system. Interferon is one of your body’s main defenses against disease.
It works kind of like a distress signal. When a virus invades your cells,
they produce interferon. It tells healthy cells to produce an enzyme that
fights the infection.
One way to study interferon is by studying how viruses get around it.
Vaccinia is particularly good at getting around interferon. Jacobs decided
to study vaccinia to learn its tricks.
Now he’s putting his knowledge to use. He is trying to engineer vaccinia
to make the live vaccine safer. He is tackling the problem from two different
angles. One way is by engineering the vaccine so that any problems can be
treated easily with antibiotics.
The second approach is to make the virus weaker. The key lies in a gene
called E3L. Jacobs discovered that vaccinia needs E3L to cause disease.
So he is trying to develop a vaccine with E3L disabled.
“E3L is the gene we’ve been working on for 20 years,” says Jacobs.
“It’s kept us going for a long time—a single gene!”
Smallpox was almost totally eliminated
during the 1970s and 1980s through a worldwide
program of vaccination.
Jet injectors gave subcutaneous (under the skin)
injections and delivered vaccine more efficiently
than traditional methods of vaccination.
25
http : //c hainreac tion.a s u .edu / ASU engineers make ion channel
sensors by etching a tiny opening
in a silicon wafer. A lipid membrane
is stretched across the opening.
The membrane carries embedded
ion channels sensitive to particular
molecules in the environment.
The molecules stick to the
membrane and change
how the ion channels
conduct electricity.
Electrodes around
the opening on each
target
side of the silicon
molecule
wafer transmit the
changes in electric
current passing
through the membrane.
top electrode
lipid membrane
ion channel
silicon
layer
resist
layer
Sensing Danger
bottom electrode
By Linley Erin Hall
A soldier walks through a building in a war zone.
Suddenly, an alarm begins going off in his pocket. He pulls out a sensor
about the size of a deck of cards. Sensors react to specific substances
or changes in their environment.
This sensor has detected anthrax.
Anthrax is a microorganism that can cause serious illness, even death.
It has been used as a biological weapon, also known as a bioagent.
The soldier alerts the rest of his patrol. They evacuate the building.
This sensor doesn’t exist—yet. But ASU researchers are working
to make it a reality. “The state of the art biosensor is pretty poor,”
says Stephen Goodnick, a professor of electrical engineering.
“You don’t want to empty the New York City subway system
based on a biosensor that’s only 30 percent accurate.”
A very good system for detecting bioagents already exists.
Gas chromatography can achieve 99 percent accuracy. But gas
chromatography is expensive and must be performed in a lab.
Portable and cheap bioagent sensors also exist. But they have
a big problem. They sometimes sound the alarm when they come into
contact with substances that aren’t dangerous. This is called a false positive.
False positives are expensive and disruptive. People have to be evacuated.
Special workers are called in to contain and clean up the bioagent.
ChainReaction.5
26
What is an ion channel?
Ion channels are proteins found in
a cell's membrane. Ions are molecules
or atoms that are positively or negatively
charged. Ion channels create tiny
openings in the membrane. They only
allow specific ions to pass through.
Researchers can measure an electric
current through single ion channels in
the membrane. Molecules in the solution
around ion channels can influence this
current even if the molecules don’t go
through the channel. ASU researchers
have used this characteristic to design
their sensor.
“Nature spent a long time designing
ion channels to be specific to molecules.
We can build on that; we don’t need
to create a whole new system,” says
ASU engineer Trevor Thornton.
If there’s no real danger, then people get annoyed.
“Our sensors have the best false positive rates because they’re
based on biology and a very specific type of binding,” says Trevor
Thornton. Thornton is also a professor of electrical engineering.
ASU is working with labs at Rush Medical College in Chicago
and six other universities. The researchers have created a sensor
that combines a tiny silicon chip with a cell membrane.
A membrane made of fat molecules forms the boundary of all cells.
A cell membrane is like the walls of a house. The walls keep some stuff
inside and other things outside. Getting into the house requires a door.
Cars enter through the garage door. People walk in through the front door.
Pets enter through a doggie door. Proteins in the cell membrane, called an
ion channel, act like doors that only allow certain materials to enter and exit.
The heart of the sensor is a silicon chip like the ones found in computers
and other electronic devices. In the chip is a tiny hole 100 microns across,
the width of a human hair. A very thin layer of Tef lon coats the chip. Tef lon
is a plastic often used in nonstick coatings on frying pans and cookie sheets.
Across the hole stretches a membrane, kind of like the ones around cells.
Cell membranes normally contain many different ion channels. The membranes
in the sensor contain many copies of the same ion channel.
The chip is surrounded by a solution of water and salts. Electrodes
on the silicon measure the electric current through the ion channels.
The current is very small, so the electronics are extremely sensitive.
When a molecule of a bioagent enters the solution surrounding the chip,
the current across the ion channels changes. The electrodes detect this
change and sound the alarm.
“It’s amazing that we are able to measure a single protein,” says Seth Wilk,
a postdoctoral research associate. “I like being able to see a device actually
do what we planned for it to do.”
The first part of the research was to figure out if the sensor could be
built at all. The researchers have proved that it can be. Now they are creating
a model with the specific characteristics they want. The sensor should fit
in a pocket. It must work for at least 90 days. And it should contain
at least a dozen different membranes. Each membrane will contain
a different ion channel that detects a different bioagent.
The researchers will test their system against chemicals that are similar
to bioagents but not as dangerous. They will also make sure that the sensor
doesn’t give false positives. A lot of work still needs to be done before one
of their sensors ends up in a soldier’s pocket. But in the future, it could
end up saving lives.
ASU researchers are using ion channels
to create sensors for biohazards. But the
technology can be used in other areas.
Ion channels are important for many
processes in the human body. Ion channels
are involved in the transmission of signals
in the nervous system. They also help
make sure that the heart beats properly.
Companies that make drugs are looking
for new medicines that affect ion channels.
ASU’s combination of silicon chips
and cell membranes could speed up
the discovery of new drugs. The sensors
could also be used in medical devices.
27
http : //c hainreac tion.a s u .edu / Who
owns
your
genes?
Imagine you go to the hospital to treat an illness. While you are there,
you mention to your doctor that you have never caught Disease X, even
though you have been exposed to it many times. Your doctor is curious.
He tells you he needs to run some tests on your illness. In reality, he wants
to study your genes. He believes that the special qualities that defend your
body against Disease X are located in your genes.
Without your knowledge or permission, he tests your genes and figures
out which ones protect you. The doctor then applies for a patent on your
genetic information. He now owns the information in your body! You are
not allowed to share or sell this information without his permission.
Think it could never happen? It did. The angry patient took his doctor
and hospital to court. But the court decided in favor of the hospital.
The case—Moore versus Regents of the University of California—set an important
precedent for gene patenting.
Until very recently, people had no way to decode information in
their genes. Today we have the ability to map out our genetic blueprints.
These kinds of scientific advances present tricky new problems in law
and ethics that we never had to think about before. There is a real
need for lawyers, judges, and lawmakers who understand both law and science
to help guide us through these legal minefields.
“The practice of law bumps into science and
technology in ways that it previously did not,”
says Andrew “Sandy” Askland, director
of the Center for the Study of Law, Science
and Technology at Arizona State University.
The center was created to help the legal system
deal with the challenges brought on by new
scientific discoveries and advances in
technology. The center supports research,
teaching, and conferences on the topics
of law, science, and technology. It helps
prepare the law professionals of today
and tomorrow to cope with these new problems.
The ability to decode and even alter the genomes
of living things has brought up a slew of new legal problems.
cross
i k:
BY DIANE BOUDREAU
n
cros link:
Genetics
and Law
“The practice of law
bumps into science
and technology
in ways that it
previously
did not.”
ANDREW ASKLAND
ChainReaction.5
The first U.S. patent
was issued on July 31, 1790 to
Samuel Hopkins of Philadelphia.
Hopkins discovered a new method
for producing potash. Potash was
an essential ingredient for making
soap, glass and gunpowder.
28
The first known
patent law was
created in Italy
in 1474.
PATENT FACTS
There are three kinds of patents
in the United States:
Utility patents cover any new and
useful process, machine, article of
manufacture, or composition of matter.
They also include improvements
on these things.
Design patents cover the new,
original and ornamental design
of an article of manufacture.
Gene patenting is one of these issues. How have we gotten to a point
where one person can patent someone else’s genes?
“The patent system is designed to encourage inventors to reveal the
nature of their inventions to the public,” says Askland. “The patent gives
the inventor protection.” A patent gives a person the exclusive right to
make, use, and sell an invention for a limited time. Usually a patent is
good for 20 years. After that time, other people may make and sell the
invention, too.
Patents play an important role in encouraging new inventions, says
Askland. Developing new products—such as allergy pills or cell phones—
can cost millions of dollars. No one wants to spend that much money and
effort just to have other people steal the idea and sell it themselves.
Think of it this way—if you do all the work of writing a report, then
you should get an “A.” If another student copied your paper over your
shoulder, you wouldn’t want that person to get the “A” instead.
Not everything can be patented. In order to get a patent,
inventors must show that their products are new, useful, and
non-obvious. In addition, people cannot patent naturally
occurring things. “If I discover a bird, I might be allowed to
name it, but I can’t patent it,” says Askland.
But wait—genes are naturally occurring things. So how can
people patent them?
To understand this, we need to look back at patent history.
In the 1930s, some farmers made hybrid plants by grafting together
two different species. The patent office refused to patent these new
plants because they were natural objects. However, the farming industry
persuaded lawmakers to change the patent laws to protect their hybrids.
Their reason was that plants do not naturally graft themselves together.
The new breeds never would have existed without human intervention.
In 1980, the Supreme Court looked at another important patent case.
A biologist developed a bacterium that would eat up oil spills. His patent
application was rejected because he merely combined two existing bacteria
to make a new one. The Supreme Court, however, reversed that decision.
They said that the new bacterium was a product of the scientist’s skills
and ingenuity, and so it could be patented.
Plant patents are given to someone
who invents or discovers and asexually
reproduces a new variety of plant.
To receive a U.S. patent, an invention
must be considered new, useful,
and non-obvious. You cannot patent
inventions that are already widely
used or described, that have no useful
purpose, or that would be obvious to
anyone with ordinary skill in that art.
James Henry Atkinson
invented the classic snapping
mousetrap that we are all
familiar with, called the
“Little Nipper,” in 1897.
In 1913, Atkinson sold his patent
to Procter, the company that has
manufactured the “Little Nipper”
ever since.
29
http : //c hainreac tion.a s u .edu / Hybrid plants and hybrid bacteria can’t be created without human help.
But no one created your genes in a lab. Even so, they are patentable.
Although your genes occur naturally, you don’t know what specific
information they contain. And you can’t use that information to help
someone else. You would need expensive lab equipment to decode the
information and put it to use. People patent genes based on the fact that
they have decoded the information and therefore should have the right
to use it to make a profit.
Currently, it is legal to patent genes, but not everyone agrees that
it should be. “A lot of people have said it was a mistake to allow patenting
of genetic information,” says Askland.
In fact, genetic patenting could have the opposite effect of what patent
law intends. It could discourage innovation instead of encouraging it.
Many undeveloped countries are wary of Americans studying their native
resources and patenting their natural remedies. Brazil now forbids scientists
to study their plants and animals without the government’s permission.
“They don’t want U.S. researchers to take this information back to the States
and profit on it without sharing that information with Brazil,” says Askland.
Gene patenting is just one of many biotechnology questions that lawyers,
lawmakers, and the courts have to grapple with today. There are many others:
Are genetically modified foods safe to eat?
Are they environmentally sound?
Should insurance companies have access to genetic test results?
Should we allow human cloning, and if so, should it be regulated?
These are questions that people never had to think about until
very recently. But they are questions that need to be answered.
cross
i k:
English chemist
Humphry Davy
invented the
first electric arc
light in 1809.
Canadians Henry
Woodward and
Matthew Evans
patented an
electric lightbulb in 1875.
Thomas Edison
purchased half
interest in the
patent from the
inventors. By 1879,
Edison developed
an improved carbon
filament and in 1885
purchased the full
patent.
Edward Hammer, a scientist
working for General Electric,
designed the compact
fluorescent bulb in 1976.
n
cros link:
Genetics
and Law
English inventor John Kemp Starley
created the first recognizably
modern bicycle—two similar-sized
wheels with rear-wheel-chain-drive.
ChainReaction.5
30
The famous author Mark Twain,
who wrote Huckleberry Finn
and Tom Sawyer, was also an
inventor. In 1871, he received
a patent for improving adjustable
and detachable straps for clothing.
His goal was to do away with
suspenders, which he considered
uncomfortable. The following
year he patented a self-pasting
scrapbook.
Genetically engineered superpowers already exist
in corn and some other plants. A type of corn has been engineered
to produce Bt toxin, which kills insect pests that eat the plant.
Imagine that scientists discovered a way to
genetically enhance human beings. They could give
people “super powers” such as telescopic vision or superhuman strength. Unfortunately, these enhancements cost
a lot of money. Imagine that you are a lawmaker. Many citizens
are asking you to propose a law forbidding these enhancements
because they will give rich people an unfair advantage. Some doctors
are asking you to keep it legal because they can make money off
the procedure. Parents are begging you to require insurance companies
to pay for the treatment, so that their kids don’t fall behind their friends.
Insurance companies are asking you not to make them
pay for it. They say the treatment is not medically
necessary and the cost will put them out of business.
What kind of laws would you suggest regarding
this technology? Would you try to ban it or allow it?
Who should pay for it?
Would you regulate it,
and if so, how?
[THOUGHT QUESTION]
What kind of human
superpowers could
genes really provide?
Athletic ability?
Longevity?
Intelligence?
31
http : //c hainreac tion.a s u .edu / HOW THE TEACHER
SPENT HIS
summer
vacation
cross
i k:
Bert Jacobs spends a lot of time learning to fight
viruses with biological tools (See page 24). But he also
knows that education is a key tool to help prevent the spread of disease.
Every summer, Jacobs joins a group of student volunteers in Tanzania,
Africa. Together, they present HIV education programs in schools.
About two-thirds of all people infected with HIV/AIDS live in SubSaharan Africa. In Tanzania alone, about 1.5 million people live with HIV.
Jacobs helps to train the student volunteers. The students come from ASU
and the University of Arizona for the eight-week program. “Support for
International Change” is the volunteer group sponsoring the program.
Jacobs teaches virology—the study of viruses—for science majors.
But he also teaches a course on HIV/AIDS for non-science majors.
n
cros link:
Science
and
culture
Tanzania is a country in eastern,
sub-Saharan Africa. It is about
twice the size of California.
Mount Kilimanjaro — the highest
point in Africa — is in Tanzania.
So is Lake Victoria, the world’s
second-largest freshwater lake.
ChainReaction.5
32
He brings in guest speakers as part of the course, including doctors,
HIV-infected patients, and others. He hopes to inspire his students the way
his own professors inspired him in the past. “I’ve had psychology students tell me,
‘This stuff is cool. I want to be a virologist!’ Just as important—or more so—
I’ve had a lot of people tell me, ‘I want to go into HIV education,’’ says Jacobs.
“Probably the biggest effect we can have on HIV today is through education.”
Jacobs says that disease prevention is not just a job for biologists.
Anyone who is developing outreach and education programs must understand cultural differences. Anthropologists, psychologists, sociologists,
linguists, and of course, teachers can all be helpful. “In Africa, I spent
a long time talking to volunteers about cultural differences. Those were
some of the most productive discussions we had there,” he says
The ASU scientist says that coming home from Africa was almost
as much of a culture shock as going. “Tanzanian people were the friendliest
people I’ve ever met in my life,” he says. “By the end of three weeks,
I knew more people on the street to say hello to than I do from living
in Tempe, Arizona for seven or eight years. By the end of the month
it took an hour to walk across the one-mile village. You were always
stopping to talk with new friends.”
About 33.2 million people
around the world live with HIV,
the virus that causes AIDS.
In 2007, about 2.5 million
people became infected with
HIV and 2.1 million people
died of AIDS.
There is good news.
The number of people living
with HIV has leveled off.
The number of new infections
has fallen. This is partly due
to programs designed to
prevent and treat the disease.
About 68 percent of all people
with HIV live in sub-Saharan
Africa—the parts of Africa
south of the Sahara Desert.
(SOURCE: WORLD HEALTH ORGANIZATION)
[THOUGHT QUESTION]
What kind of cultural
differences might affect
the way diseases are
prevented, spread,
or treated?
Support for International Change http://www.sichange.org/home/
http://
chainreaction
.asu.edu
Ask
a
Biologist
http://askabiologist.asu.edu
Ask a Biologist is
an outreach program of
the Arizona State University
School of Life Sciences
Science is about curiosity. Science is about asking questions.
Other resources at ASU:
One answer often leads to a brand new set of questions. That is how
science works. That is what learning is all about. Just think how great
it would be if you could ask a real scientist for help with a tough question.
Now you can. You can also hear the scientists themselves via podcasts
from the site. Don’t have a question? No problem. The site features backyard experiments you can do at home, coloring pages for young students,
on-line quizzes, and a new comic book science mystery with Dr. Biology.
Check it all out at: http://askabiologist.asu.edu
ASU Mars Education Program
Make your own discoveries in space science.
http://marsed.asu.edu
Ecology Explorers
Work side by side with ASU scientists
and investigate your schoolyard.
http://caplter.asu.edu/explorers
ASU in the Community
ASU offers more than 1,100 outreach programs
http://community.uui.asu.edu/