Microbiology and Immunology

INTRODUCTION

vii

•

Although microbiology and immunology are fundamen-

tally separate areas of biology and medicine, they combine to

provide a powerful understanding of human health and dis-

ease—especially with regard to infectious disease, disease

prevention, and tragically, of the growing awareness that

bioterrorism is a real and present worldwide danger.

World of Microbiology and Immunologyis a collection of

600 entries on topics covering a range of interests—from biog-

raphies of the pioneers of microbiology and immunology to

explanations of the fundamental scientific concepts and latest

research developments. In many universities, students in the

biological sciences are not exposed to microbiology or

immunology courses until the later half of their undergraduate

studies. In fact, many medical students do not receive their

first formal training in these subjects until medical school.

Despite the complexities of terminology and advanced knowl-

edge of biochemistry and genetics needed to fully explore

some of the topics in microbiology and immunology, every

effort has been made to set forth entries in everyday language

and to provide accurate and generous explanations of the most

important terms. The editors intend World of Microbiology

and Immunologyfor a wide range of readers. Accordingly, the

articles are designed to instruct, challenge, and excite less

experienced students, while providing a solid foundation and

reference for more advanced students. The editors also intend

that World of Microbiology and Immunologybe a valuable

resource to the general reader seeking information fundamen-

tal to understanding current events.

Throughout history, microorganisms have spread deadly

diseases and caused widespread epidemics that threatened and

altered human civilization. In the modern era, civic sanitation,

water purification, immunization, and antibiotics have dramat-

ically reduced the overall morbidity and the mortality of dis-

ease in advanced nations. Yet much of the world is still rav-

aged by disease and epidemics, and new threats constantly

appear to challenge the most advanced medical and public

health systems. For all our science and technology, we are far

from mastering the microbial world.

During the early part of the twentieth century, the science

of microbiology developed somewhat independently of other

biological disciplines. Although for many years it did not exist

as a separate discipline at all—being an “off-shoot” of chem-

istry (fermentation science) or medicine—with advances in

techniques such as microscopy and pure culturing methodolo-

gies, as well as with the establishment of the germ theory of

disease and the rudiments of vaccination, microbiology sud-

denly exploded as a separate discipline. Whereas other biolog-

ical disciplines were concerned with such topics as cell struc-

ture and function, the ecology of plants and animals, the repro-

duction and development of organisms, the nature of heredity

and the mechanisms of evolution, microbiology had a very dif-

ferent focus. It was concerned primarily with the agents of

infectious disease, the immune response, the search for

chemotherapeutic agents and bacterial metabolism. Thus,

from the very beginning, microbiology as a science had social

applications. A more detailed historical perspective of the

development of the field may be found in the article “History

of Microbiology” in this volume.

Microbiology established a closer relationship with other

biological disciplines in the 1940s because of its association

with genetics and biochemistry. This association also laid the

foundations for the subsequent and still rapidly developing

field of genetic engineering, which holds promise of profound

impact on science and medicine.

Microorganisms are extremely useful experimental sub-

jects because they are relatively simple, grow rapidly, and can

be cultured in large quantities. George W. Beadle and Edward

L. Tatum studied the relationship between genes and enzymes

in 1941 using mutants of the bread mold Neurospora. In 1943

Salvador Luria and Max Delbrück used bacterial mutants to

show that gene mutations were apparently spontaneous and

not directed by the environment. Subsequently, Oswald

Avery, Colin M. MacLeod, and Maclyn McCarty provided

strong evidence that DNA was the genetic material and car-

ried genetic information during transformation. The interac-

tions between microbiology, genetics, and biochemistry soon

womi_fm 5/6/03 1:34 PM Page vii