Microbiology and Immunology

WORLD OF MICROBIOLOGY AND IMMUNOLOGY Gonorrhea

251

•

In 1873, Golgi found that silver salts could be used to

dye neurons. The neurons turned black and stood out clearly

from surrounding tissue. Golgi perfected his technique so that

the addition of just the right amount of dye for just the right

period of time would highlight one or another part of the neu-

ron, a single complete neuron, or a group of neurons.

Golgi’s new technique resolved some questions about

the nervous system, but not all. He was able, for example, to

confirm the view of Wilhelm von Waldeyer-Hartz that neurons

are separated by narrow gaps, synapses, and are not physically

connected to each other. He was not able to completely explain,

however, the complex, overlapping network of dendrites.

While studying the brain of a barn owl in 1896, Golgi

made a second important discovery. He found previously

undetected bodies near the nuclear membrane. The function of

those bodies, now known as Golgi apparatus, or Golgi bodies,

is still not understood. For his research on the nervous system,

Golgi was awarded a share of the 1906 Nobel Prize for phys-

iology or medicine.

Between 1885 and 1893, Golgi was also involved in

research on malaria. He made one especially interesting dis-

covery in this field, namely that all the malarial parasitesin an

organism reproduce at the same time, a time that corresponds

to the recurrence of fever.

In addition to his scientific work, Golgi was active in

Italian politics. He was elected a Senator in 1900 and served

in a number of administrative posts at Pavia. Golgi died in

Pavia on January 21, 1926.

See alsoCell cycle and cell division; Cell membrane trans-

port; Golgi body; Malaria and the physiology of parasitic

inflections

GGolgi body OLGI BODY

The Golgi body, or Golgi apparatus is a collection of flattened

membrane sacks called cisternae that carry out the processing,

packaging, and sorting of a variety of cellular products in higher

plants and animals. This important cellular organelle was named

in honor of Camillo Golgi, the Italian neuroanatomist who first

described it in brain cells late in the nineteenth century. An indi-

vidual Golgi apparatus is usually composed of four to eight cis-

ternae, each a micron or less in diameter stacked on top of each

other like pancakes. Many cisternal stacks interconnected by

tubules and mobile transport vesicles make up a Golgi complex,

which often is located near the nucleusin the center of the cell.

In some animal cells, this complex can be huge, filling much of

the cytoplasmic space. In some plant cells, on the other hand,

many small, apparently independent Golgi apparatuses are dis-

tributed throughout the cell interior.

Each Golgi stack has a distinct orientation. The cisor

entry face is the site at which transport vesicles bringing newly

synthesized products from the endoplasmic reticulum dock

with and add their contents to the Golgi cisternae. A complex

network of anastomosing (connecting) membrane tubules

attach to and cover the fenestrated cisternae on the cisface and

serves as a docking site for transport vesicles. From the cis

face a flow of vesicles carry transport and chaperone proteins

back to the endoplasmic reticulum, while secretory products

move on into the medial cisternae where further processing

takes place. Finally, the products move to the transor exit face

where they undergo final processing, sorting, and packaging

into vesicles that will carry them to the cell surface for secre-

tion or to other cellular organelles for storage or use. Complex

oligosaccharides are synthesized in the Golgi apparatus, and

glycoproteins are assembled as materials move through the

compartments of this organelle. A unique set of enzymesand

chaperone proteins occur in each of the Golgi compartments

to direct and carry out this complex set of reactions.

See alsoCell cycle and cell division; Cell membrane transport

GGonorrheaONORRHEA

Gonorrhea is among the most common sexually transmitted

diseases(STD) and is also among the most common bacterial

infections in adults. In the United States, between 2.5 and 3

million cases are reported each year, most occurring in people

under age 30. In its early stages, gonorrhea may cause no

symptoms and therefore, can be spread by unsuspecting vic-

tims. In females, gonorrhea often remains asymptomatic but

can lead to vaginal itching, discharge, or uterine bleeding and

other serious complications. An infected woman who gives

birth can transmit the disease to her infant, often resulting in

childhood blindness. As a precaution, silver nitrate is routinely

administered to the eyes of newborns to prevent this condition.

In males, gonorrhea causes infection of the urethra and painful

urination. Though not deadly, the disease if untreated can infect

other genital organs. If the infection spreads throughout the

blood stream, it can cause an arthritis-dermatitis syndrome.

Gonorrhea was described in early writings from Egypt,

China, and Japan. Warnings against “unclean discharge from

the body” appear in the Bible. A diagnostic description of the

disease was written in the Middle Ages. In the late fifteenth

century, a syphilisepidemic raged throughout Europe, though

at that time, syphilis was often confused with gonorrhea and

some physicians assumed that gonorrhea was the first stage of

syphilis. The gram-negative bacterium that causes gonorrhea

was discovered in 1879 by Albert Neisser (1855–1916), a

German physician who went on to identify the bacterial cause

for leprosy. German immunologist Paul Ehrlichnamed the

bacterium Gonococcus. Since then, five types of the

Gonococcusorganism have been identified.

A test for the presence of Gonococcusbacterium serves

as the diagnostic tool. The first effective treatments for gonor-

rhea were the sulfonamides, which became available in 1937.

During World War II, penicillinbecame widely available for

the treatment of gonorrhea and other bacterial disease.

However, while penicillin and related antibioticsare effective

in about 90% of cases, some strains of the Gonococcusare

becoming resistant to penicillin.

See alsoHistory of the development of antibiotics; History of

public health

womi_G 5/6/03 3:18 PM Page 251