How can we detect and study
life in soils from other planets
and still remain safe from the
danger posed by alien life forms?
Pennsylvania State University
microbiologists are at work on
this problem as the U. S. space
program expands the search for
extraterrestrial life.
At the request of the National
Aeronautics and Space Ad
ministration (NASA), Dr. Lester
E. Casida, Jr., professor of
microbiology, has begun an effort
to determine if soil which has
been sterilized to kill all life
forms, to reduce the risk of
contamination, can still yield
information about the life it
contained.
Can we kill alien life forms, in
other words, without destroying
the evidence of their existence?
So far, using Earth soil, Drr
Casida and his assistants David,
L. Balkwill and David P. Labeda,
Ph.D. candidates in microb
iology, College of Science, have
found that one form of heat
sterilization cannot be used. Dr.
Casida says, “the cells are not
only killed, but are totally
Soil Study Of Planets Being Conducted
destroyed by the process.”
However, the Penn State team
has found that another heat
method leaves many of the dead
cells at least partially intact and,
Dr. Casida adds, ‘‘very
preliminary work on chemical
sterilization looks like it might
work as well.”
Dr. Casida has been studying
terrestrial soil bacteria for over
15 years and has discovered
Support for AEB
“California Egg Producer,
Jack Hayre, recently presented
American Egg Board with a
check for $5,000 as a token of his
support for the national ad
vertising and educational effort
currently being undertaken by
AEB. This gift was gratefully
acknowledged with a Resolution
of Appreciation passed by the
AEB Executive Committee at its
recent meeting,” so stated Ed
ward D. Murphy, Chairman of
AEB’s Board of Directors.
“This unsolicited and volun
tary investment in our national
several new types of bacteria
which are extremely difficult to
isolate for study in the
laboratory. He and his students
have also developed two
techniques (thin-sectioned and
frozen fractured preparations)
which make it possible to use the
electron microscope to study
bacteria as they occur naturally
in the soil. Using these non
destructive techniques, they have
Program Grows
promotional program is most
welcome, and I hope indicative of
the growing support on the part of
the egg industry for a strong
national program,” continued
Chairman Murphy.
While additional funds have
been provided to AEB via carton
manufacturers and poultry
breeders, the support of the
producers, packers, and
distributors of eggs is also vital to
the growth of these new
programs being proposed by the
American Egg Board.
Lancaster Farming, Saturday, October 6,1973 —
discovered that bacterial cysts
and dwarf bacteria, too small to
be seen with conventional light
microscopes, frequently inhabit
soil.
Dr. Casida explains that the
other usual techniques for
studying soil bacteria require
trying to make them grow in the
laboratory on special media or
food. He says, “these growth
methods are frequently un
successful since 99 jier cent of
the bacteria in soil have extreme
difficulty in adapting to growth
under laboratory conditions.”
With this fact in mind, Dr.
Casida warns that the first efforts
to detect life on Mars during the
unmanned Viking mission in 1976
may prove disappointing. He
explains that the life-detecting
device that will be soft-landed on
Mars will not bring any samples
back to earth for study. The
automated device will scoop-up
and test soil for signs of life,
relying completely on growth
techniques or' metabolic
responses, and then relay the
information back to earth. Dr.
Casida notes: “Since we can’t
grow most of the organisms in
Earth soil it should be doubly
difficult to grow Mars bacteria by
remote control.”
He emphasizes that negative
results from Viking will not in
dicate a lifeless Mars but, rather,
increase importance of the
development of non-growth
detection techniques such as the
use of electron microscopy.
If Dr. Casida’s current NASA
funded study is successful, a soil
specimen gathered from another
planet may one day be sterilized
in transit to kill living material
before it gets to Earth. Then, with
the threat of damage to life on
Earth diminished, the dead
bacteria can be detected and
studied using Dr. Casida’s
techniques.
I
Clay tablets dating from
about 2000 B.C. show that
in Babylonia valuables were
deposited for a service
charge of 1/16th of what
they were worth. Interests
on loans ran as high as
33-1/3 percent!
43