(EDITOR’S NOTE: “Common Science” is a science
the Ph.D. in molecular biology and biochemistry from
Purdue University. He teaches chemistry and biology
at Ouachita Baptist University in Arkadelphia, Arkan-
sas. “Common Science’ is sponsored by The National
Science Foundation and appears periodically in The
Dallas Post.) Bacteria are microscopic creatures that
are found everywhere. Some forms of bacteria make
us sick. Most do not. In fact we have large colonies of
bacteria living in our intestines. Not only do they not
hurt us, these bacteria, E. coli, actually help by
digesting some food materials for us that we do not
digest.
Bacteria are single celled creatures with a very
simple structure. They do not have a nucleus as most
of our cells do, but they do contain DNA. In addition to
the large circular DNA molecule that provides the
genetic information for each bacterial cell, a second
much smaller circle of DNA can be absorbed by
bacteria under certain conditions. This smaller type of
DNA is called a plasmid.
Plasmids can be manipulated in the laboratory.
They can be cut open and ‘‘foreign’” DNA can be
added to the plasmid DNA. When the circle is
reclosed, a larger plasmid results. For example, think
of a black hula hoop. Take a razor blade and cut
through the hoop in one place. Now add a 24 inch
section of red hula hoop plastic by inserting it into the
cut place. Tape the junction at each end of the red
section where it joins the black. You now have a
larger circle because of the added red section. The red
section corresponds to the foreign DNA added to a
plasmid. If this new plasmid is mixed with bacterial
cells that have been treated with calcium chloride, the
cells will absorb the plasmid and the foreign DNA will
be placed in the bacterial cell. If everything goes well,
the bacteria will use the foreign DNA to make a
protein.
Insulin is currently being made this way. Until
recently, diabetics depended on insulin isolated from
the pancreas of slaughter house animals like cows and
pigs. Now bacteria can make human insulin from
human insulin DNA (a gene) placed in a bacterial
plasmid. Other such genetically engineered products
are already available; human growth hormone; a
vaccine for foot-and-mouth disease; and interferon, an
antivirus protein that may be useful against some
cancers. And many, many more will be available
within a few years.
Several questions arise. How can we tell if a
bacterial cell has taken up the plasmid with the insulin
gene? Fortunately, the plasmids used for these tech-
niques contain genes of their own. Each plasmid has
one or more genes that code for resistance to certain
antibiotics. Once the bacterial cells have had a chance
to absorb the plasmid, an antibiotic is added. Any cells
which do not have a plasmid will be killed by the
antibiotic. Those that do have the plasmid will
survive.
How can an insulin gene placed in a microscopic cell
produce enough insulin to be of value to people?
Bacteria grow very rapidly at body temperature if
they have plenty of food. In twenty minutes one
bacterial cell splits into two. Twenty minutes later,
two become four. Every twenty minutes they double
again. If this continued for 48 hours under ideal
conditions, there would be a mass of bacteria equal to
the mass of the earth! That doesn’t happen, of course,
because they run out of food or they begin to die from
the accumulation of their own waste products. Still,
from one cell billions upon billions of cells can be
produced in a short period of time, each making
insulin molecules. A few of the cells can be saved and
the whole process can be begun again and again.
Where does the human insulin gene come from?
This is trickier. As was mentioned last week in
Chemical Morse Code, a human gene contains DNA
that has interruptions in its coding information.
Bacterial DNA does not. If the human insulin gene
were placed directly into bacteria, the protein mole-
cule that would be made would contain too much extra
material, so it would not work. Instead the messenger
RNA made from human DNA in the pancreas is
isolated after the original RNA has been cut and
spliced to the form of RNA used to assemble amino
acids into insulin. The processed RNA is purified and
mixed with a special enzyme that can make DNA
from RNA. This new synthetic gene for insulin can be
inserted into a plasmid and then put into bacteria.
Now the bacteria can make human insulin that will
work.
What does the future hold for these genetic engineer-
ing techniques using bacteria? The sky is the limit.
Any gene or protein made by any living system could
be produced in large quantities by the bacterial
factories. You may see products like dynorphin, a pain
killer 200 times as effective as morphine; Factor s, a
sleep promoting peptide; bombesin, a peptide that
signals the body that it has had enough to eat; and a
hormonal combination called MSH-ACTH, which facili-
tates learning, concentration and memory.
New arrangements of genes in bacteria may reduce
or eliminate the need for nitrogen fertilizer by placing
nitrogen-fixing genes into soil bacteria that can be
used with any crop. Genetic defects of the blood cells
like sickle cell anemia or B-thalassemia could be
corrected by removing bone marrow cells from an
individual, adding the gene to correct the defect and
replacing the bone marrow into the individual. Bac-
teria, of course, could be used to produce large enough
quantities of the correct genes using the same
techniques described above.
Only the tip of the iceberg has been uncovered. The
world of pharmacy as we know it will be turned upside
down by the products of this genetic engineering
explosion. For further reading see the December 1984
issue of NATIONAL GEOGRAPHIC.
DALLAS
J
MICHELE FARRIS
KRISTYN POST
SHERI PROKOPCHAK is the
daughter of Mr. and Mrs. Michael
Prokopchak of Dallas. Sheri has
been involved in majorettes and the
spring play in her junior year. She
is now a member of the Senior
Steering Committee and of the year-
book staff. Sheri likes to go out with
friends, dance, cruise, and listen to
music when not working part-time
at the Acme. Her future plans
include pursuing a career in the
medical field.
-0-
MARTY KRINER is the son of
Larry and Jann Kriner of Trucks-
ville. Marty enjoys hunting and
fishing in his free time. He plans to
attend college to later become an
optometrist.
-0-
LISA CHANEY is the daughter of
Mr. and Mrs. Edgar Chaney of
Trucksville. She is involved in can-
dystriping at the Nesbitt Memorial
Hospital. She has played the organ
for five years, and likes to listen to
the radio. Lisa would like to become
a nurse, but is undecided as to
where to attend school.
-0-
DEBBIE HONEYWELL is the
daughter of Thomas and Bev Hone-
ywell of Dallas. Debbie is the vice
president of the Key Club. She likes
to dance, play tennis and to attend
plays. Debbie plans to attend
PRODUCED BY
-0-
SHARON CHUPAS is the daugh-
ter of Ron and Gloria Chupas of
Dallas. She takes art lessons at Sue
Hand’s where she likes to paint.
Sharon works part-time at Bonanza.
She is planning to go to art school
for commercial art.
-0-
PEGGY “PIGGLES” SMITH is
the daughter of Don and Helen
Smith of Dallas. She likes to drive
and go out with her friends. Peggy
works at McDonald’s. Her future
plans include atending secretarial
school or attending Empire Beauty
School.
-0-
GENA “GEAN” MURPHY is the
daughter of Al and Anna Winkler of
Dallas. She enjoys to play volley-
ball, to go out with her friends, to go
shopping and to talk on the phone.
Gena works part-time at Burger
King. She plans to attend junior
college for secretarial studies.
-0-
CONGRATULATIONS to the
cheerleaders for placing second in a
state invitational cheerleading com-
petition.
HEY
KIDS!
(TO AGE 12)
The Best Part Is IT'S FREE!
MARCH 31st thru APRIL 6th
Monday thru Friday, 1:45 & 7:45 P.M.,
Saturday 9:45 A.M., 1:45 & 7:45 P.M.,
Sunday 2 P.M.
ry
fe
f Y
Zip =
l— Wo!
* 2-HOUR SHOW
e 25 THRILLING ACTS
Chabaku speaks
Area rallies
around
DHS girls
Over 75 area businesses, school
and community groups, and individ-
uals supported the Dallas High
School Cheereleaders in their fun-
draising efforts for their recent trip
to Florida to, compete in the Univer-
sal Cheerleading Association’s
National Championship. According
to Varsity Coach Sheila Bonawitz of
Shavertown, the ‘‘community really
rallied around the girls, and gave us
a tremendous boost. There are so
many people and groups to thank,
that I just have to say one big thank
you to the whole community. We
have been totally overwhelmed by
the response.”
Among the groups who aided the
Cheerleaders was the Dallas Unico
Club which sponsored a:Spaghetti
Dinner and gave the proceeds to the
irls. The Junior High Student
ouncil donated sweatshirts and the
Senior High School Council contrib-
uted $100.00. Many area businesses
allowed Donations Buckets to be
placed in their stores, as well as
posters announcing the various fun-
draising activities. Several busi-
nesses donated food and provided
equipment for Hoagie Sales. Other
area high school squads demon-
strated their talents at a Cheerlead-
ing Exhibition.
DALLAS POST |
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OF
BACK
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Deliver The DALLAS POST
in your NEIGHBORHOOD.
For more information
Call Jean at 675-5211
“New Developments
in
Biomedical Ethics”
7:30 PM Wednesday April 9
J. Carroll McCormick Campus
Ministry Center
FRIDAY NIGHT AND SUNDAY | NS
AFTERNOON PERFORMANCES % -
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