Microbiology and Immunology

WORLD OF MICROBIOLOGY AND IMMUNOLOGY Murray, Robert

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The diagnosis of mumps in children is usually made on

the basis of its very characteristic symptoms. The virus can be

cultured, however, and can be isolated from a patient by tak-

ing a swab from the buccal (mouth) outlet of the parotid gland

duct. The swab is then broken off into viral transport medium.

Cultureof the virus is rarely necessary in a straightforward

case of mumps parotitis. Occasionally, it is necessary to iso-

late the virus from the cerebro-spinal fluid (CSF) of patients

with CNS complications such as mumps meningitis. Also,

serological investigations may be useful in aseptic meningitis

and encephalitis.

Avaccinefor mumps was developed by the American

microbiologist, John Enders, in 1948. During World War II,

Enders had developed a vaccine using a killed virus, but it was

only moderately and temporarily successful. After the war, he

began to investigate ways of growing mumps virus in a sus-

pension of minced chick embryo and ox blood. The technique

was successful and Enders’ live virus vaccine is now routinely

used to vaccinate children. In the U.S.A., the live attenuated

mumps vaccine is sometimes given alone or together with

measlesand/or rubella vaccine. The MMR vaccine came

under investigation with regard to a possible link to autism in

children. The United States Centers for Disease Controlcon-

cludes that current scientific evidence does not support any

hypothesis that the MMR vaccine causes any form of autism.

The hypothetical relationship, however, did discourage and

continues to discourage some parents from allowing their chil-

dren to receive the triple vaccine.

See alsoAntibody-antigen, biochemical and molecular reac-

tions; History of immunology; History of public health;

Immunity, active, passive and delayed; Immunology;

Varicella; Viruses and responses to viral infection

MMurchison meteoriteURCHISON METEORITE

The Murchison meteorite was a meteorite that entered

Earth’s atmosphere in September, 1969. The meteor frag-

mented before impact and remnants were recovered near

Murchison, Australia (located about 60 miles north of

Melbourne). The fragments recovered dated to nearly five

billion years ago—to the time greater than the estimated age

of Earth. In addition to interest generated by the age of the

meteorite, analysis of fragments revealed evidence of carbon

based compounds. The finds have fueled research into

whether the organic compounds were formed from inorganic

processes or are proof of extraterrestrial life dating to the

time of Earth’s creation.

In particular, it was the discovery of amino acids—and

the percentages of the differing types of amino acids found

(e.g., the number of left handed amino acids vs. right handed

amino acids—that made plausible the apparent evidence of

extraterrestrial organic processes, as opposed to biological

contaminationby terrestrial sources.

If the compounds prove to be from extraterrestrial life,

this would constitute a profound discovery that would have far

reaching global scientific and social impact concerning pre-

vailing hypotheses concerning the origin of life. For example,

some scientists, notably one of the discoverers of the structure

of DNA, Sir Francis Crick, assert that in the period from the

formation of Earth to the time of the deposition of the earliest

discovered fossilized remains, there was insufficient time for

evolutionary process to bring forth life in the abundance and

variety demonstrated in the fossil record. Crick and others

propose that a form of organic molecular “seeding” by mete-

orites exemplified by the Murchison meteorite (meteorites

rich in complex carbon compounds) greatly reduced the time

needed to develop life on Earth.

In fact, the proportions of the amino acids found in the

Murchison meteorite approximated the proportions proposed

to exist in the primitive atmosphere modeled in the Miller-Urey

experiment. First conducted in 1953, University of Chicago

researchers Stanley L. Millerand Harold C. Urey developed an

experiment to test possible mechanisms in Earth’s primitive

atmosphere that could have produced organic molecules from

inorganic processes. Methane (CH 4 ), hydrogen (H 2 ), and

ammonia (NH 3 ) gases were introduced into a moist environ-

ment above a water-containing flask. To simulate primitive

lightning discharges, Miller supplied the system with electri-

cal current. Within days, organic compounds formed—includ-

ing some amino acids. A classic experiment in molecular

biology, the Miller-Urey experiment established that the con-

ditions that existed in Earth’s primitive atmosphere were suf-

ficient to produce amino acids, the subunits of proteins

comprising and required by living organisms. It is possible,

however, that extraterrestrial organic molecules could have

accelerated the formation of terrestrial organic molecules by

serving as molecular templates.

In 1997, NASA scientists announced evidence that the

Murchison meteorite contained microfossils that resemble

microorganisms. The microfossils were discovered in fresh

breaks of meteorite material. The potential finding remains the

subject of intense scientific study and debate.

University of Texas scientists Robert Folk and F. Leo

Lynch also announced the observation of fossils of terrestrial

nanobacteria in another carbonaceous chondrite meteorite

named the Allende meteorite. Other research has demonstrated

that the Murchison and Murray meteorites (a carbonaceous

chondrite meteorite found in Kentucky) contain sugars critical

for the development of life.

See also Evolution and evolutionary mechanisms;

Evolutionary origin of bacteria and viruses; Life, origin of

MUREIN•seePEPTIDOGLYCAN

MMurray, Robert URRAY, ROBERT(1919- )

British bacteriologist

Robert George Everitt Murray is professor emeritus and for-

mer department chair of the Department of Microbiology and

Immunologyat the University of Western Ontario in London.

His numerous accomplishments in bacterial taxonomy, ultra-

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