WORLD OF MICROBIOLOGY AND IMMUNOLOGY Leeuwenhoek, Antoni van343•
Lederberg’s work in genetics eventually proved to be one of
the foundations of gene mapping, which eventually led to
efforts to genetically treat disease and identify those at risk of
developing certain diseases.
Known as brilliant laboratory scientist and technician,
Lederberg was also concerned with the role of science in soci-
ety and the far-reaching effects of scientific discoveries, par-
ticularly in genetics. In a Pan American Health
Organization/World Health Organization lecture in biomedical
sciences called “Health in the World Tomorrow,” Lederberg
acknowledged concerns of the public, and even some scien-
tists, over the newfound ability to tamper with the genetic
codeof life. However, he was more concerned with the many
ethical questions that would arise over the inevitable success
of the technological advances in microbiology and genetics.
Lederberg saw the biological revolution as “a philosophical
one” that was to bring a “new depth of scientific understand-
ing about the nature of life.” He foresaw advancements in the
treatment of cancer, organ transplants, and geriatric medicine
as presenting a whole new set of ethical and social problems,
such as the availability and allocation of expensive health-care
resources.
Lederberg was also interested in the study of biochemi-
cal life outside of Earth and coined the term exobiologyto
refer to such studies. Along with physicist Dean B. Cowie, he
expressed concern in Scienceover the possible contamination
of biological life on other planets from microbes carried by
human spacecraft. He was also a consultant to the U.S. Viking
space missions to the planet Mars.
Lederberg’s career included an appointment as chair-
man of the new genetics department at Stanford University in- In 1978 he was appointed president of Rockefeller
University. Working with his first wife, Esther Zimmer, a for-
mer student of Tatum’s whom Lederberg married in 1946,
Lederberg investigated the role of bacterial enzymesin sugar
metabolism. He also discovered that penicillin’s ability to kill
bacteria was due to its preventing synthesis of the bacteria’s
cell walls. Among Lederberg’s many honors were the Eli Lilly
Award for outstanding work by a scientist under thirty-five
years of age and the Alexander Hamilton Medal of Columbia
University.
See also Escherichia coli (E. coli); Microbial genetics;
Molecular biology and molecular genetics; Viral geneticsLLeeuwenhoek, Anton vanEEUWENHOEK, ANTONI VAN(1632-1723)
Dutch microscopistAntoni van Leeuwenhoek is best remembered as the first
person to study bacteriaand “animalcules,” or one-celled
organisms now known as protozoa. Unlike his contempo-
raries Robert Hookeand Marcello Malpighi, Leeuwenhoek
did not use the more advanced compound microscope;
instead, he strove to manufacture magnifying lenses of
unsurpassed power and clarity that would allow him to
study the microcosm in far greater detail than any other sci-
entist of his time.Leeuwenhoek was born on October 24, 1632, in Delft,
Holland. Although his family was relatively prosperous, he
received little formal education. After completing grammar
school in Delft, he moved to Amsterdam to work as a draper’s
apprentice. In 1654, he returned to Delft to establish his own
shop, and he worked as a draper for the rest of his life. In addi-
tion to his business, Leeuwenhoek was appointed to several
positions within the city government, which afforded him the
financial security to spend a great deal of time and money in
pursuit of his hobby, lens grinding. Lenses were important
tools in Leeuwenhoek’s profession, as cloth merchants often
used small lenses to inspect their products. His hobby soon
turned to obsession, however, as he searched for more and
more powerful lenses.
In 1671, Leeuwenhoek constructed his first simple
microscope. It consisted of a tiny lens that he had ground by
hand from a globule of glass and placed within a brass holder.
To this, he had attached a series of pins designed to hold the
specimen. It was the first of nearly six hundred lenses ranging
from 50 to 500 times magnifications that he would grind dur-
ing his lifetime. Through his microscope, Leeuwenhoek
examined such substances as skin, hair, and his own blood. He
studied the structure of ivory as well as the physical composi-
tion of the flea, discovering that fleas, too, harbored parasites.
Leeuwenhoek began writing to the British Royal
Society in 1673. At first, the Society gave his letters littleAntoni van Leeuwenhoek, the “father” of microscopy, pictured with
one of his light microscopes used to observe “animalcules.”womi_L 5/6/03 3:32 PM Page 343