Uric Acid MoleculeThe interaction of mRNA in a eukaryote cell.The exon portion of a DNA strand encodes a specific portion of a protein. In some organisms exons are situated between introns which are spliced from the strand before it is exported from the nucleus and do not code for protein parts.
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Lesch-Nyhan syndrome

Lesch-Nyhan syndrome (LNS) is a rare, inherited disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). LNS is an X-linked recessive disease: the gene is carried by the mother and passed on to her son. LNS is present at birth in baby boys. Patients have severe mental and physical problems throughout life. The lack of HPRT causes a build-up of uric acid in all body fluids, and leads to symptoms such as severe gout, poor muscle control, and moderate mental retardation, which appear in the first year of life. A striking feature of LNS is self-mutilating behaviors, characterized by lip and finger biting, that begin in the second year of life. more...

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Abnormally high uric acid levels can cause sodium urate crystals to form in the joints, kidneys, central nervous system and other tissues of the body, leading to gout-like swelling in the joints and severe kidney problems. Neurological symptoms include facial grimacing, involuntary writhing, and repetitive movements of the arms and legs similar to those seen in Huntington's disease. The direct cause of the neurological abnormalities remains unknown. Because a lack of HPRT causes the body to poorly utilize vitamin B12, some boys may develop a rare disorder called megaloblastic anemia.

The symptoms caused by the buildup of uric acid (arthritis and renal symptoms) respond well to treatment with drugs such as allopurinol that reduce the levels of uric acid in the blood. The mental deficits and self-mutilating behavior do not respond to treatment. There is no cure, but many patients live to adulthood.

LNS is rare, affecting about one in 380,000 live births. It was first described in 1964 by Dr. Michael Lesch and Dr. William Nyhan.


LNS is characterized by three major hallmarks: neurologic dysfunction, cognitive and behavioral disturbances, as well as uric acid overproduction (hyperuricemia). Some may also be afflicted with anemia (macrocytic). Virtually all patients are male, and male victims suffer delayed growth and puberty, and most develop shrunken testicles or testicular atrophy. Female carriers are at an increased risk for gouty arthritis, but are usually otherwise unaffected.

Overproduction of uric acid

One of the first symptoms of the disease is the presence of sand-like crystals of uric acid in the diapers of the affected infant. Overproduction of uric acid may lead to the development of uric acid crystals or stones in the kidneys, ureters, or bladder. Such crystals deposited in joints later in the disease may produce gout-like arthritis, with swelling and tenderness.

The overproduction of uric acid is present at birth, but may not be recognized by routine clinical laboratory testing methods. The serum uric acid concentration is often normal, as the excess purines are promptly eliminated in the urine. The crystals usually appear as an orange grainy material, or they may coalesce to form either multiple tiny stones, or distinct large stones that are difficult to pass. The stones, or calculi, usually cause hematuria (blood in the urine) and increase the risk of urinary tract infection. Some victims suffer kidney damage due to such kidney stones. Stones may be the presenting feature of the disease, but can go undetected for months or even years.

Nervous system impairment

The periods before and surrounding birth are typically normal in individuals with LNS. The most common presenting features are abnormally decreased muscle tone (hypotonia) and developmental delay, which are evident by three to six months of age. Affected individuals are late in sitting up, while most never crawl or walk. Lack of speech is also a very common trait associated with LNS.

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Yellowstone's biological resources - Column
From Environment, 3/1/97 by Anna-Louise Reysenbach

Charles C. Chester's article on Yellowstone's thermophilic microorganisms (October 1996) exposes a whole other dimension of biodiversity: the microbial world. Though widely ignored, microscopic forms of life may actually be our greatest biological resource. Reading the article, I was reminded of a passage in Edward O. Wilson's autobiography, The Naturalist:

Most of Earth's largest species - mammals, birds, and trees - have been seen and documented. But microwildernesses exist in a handful of soil or aqueous silt collected almost anywhere in the world. They at least are close to a pristine state and still unvisited. . . . If I could do it all over again, and relive my vision of the twenty-first century, I would be a microbial ecologist. Ten billion bacteria live in a gram of ordinary soil, a mere pinch held between thumb and forefinger. They represent thousands of species, almost none of which are known to science. Into that world I would go with the aid of modern microscopy and molecular analysis.(1)

Thus, in asserting that microorganisms are a resource rather than just "germs," Chester is clearly in good company!

Without question, the issues surrounding the ownership of the Taq polymerase are complex (and all the more so because strains of Thermus aquaticus have been isolated elsewhere in the world and other thermally stable polymerases have been discovered). The real moral of the story, however, is that the microbial world is a resource that deserves protection because certain natural products can have an unfathomable impact on science along with offering enormous benefits for society.

The development of the polymerase chain reaction (PCR) in 1983, which T. aquaticus made possible, was a major methodological breakthrough in molecular biology. PCR has numerous applications, ranging from diagnostics to pure research. The Human Genome Project, for example, could never have been conceived - let alone carried out - without it. PCR is also widely used in medicine. It has hastened the discovery of the molecular basis of many malignant, infectious, and genetic diseases and is currently used in the diagnosis of Lesch-Nyhan syndrome (a rare, usually fatal genetic disease that affects young boys) and muscular dystrophy as well as the prenatal diagnosis of hemophilia A. In addition, this technique has important applications in organismal and population biology, evolutionary studies, and conservation. A recent Science article on speciation(2) provides a good example of its use in evolutionary studies: Evidence developed with the aid of PCR shows that species diversity within the Amazon basin depends not only on the Amazon River but also on natural barriers such as ridges.

PCR has brought about a revolution in microbiology and our understanding of microbial diversity. As Chester notes, the diversity of microbial species dwarfs that of larger plants and animals - and we continue to discover new species, new branches of microbial life whose existence we never suspected. Even more important, these life forms embody a large amount of physiological diversity: To meet their energy and carbon requirements, microbes perform almost every biological transformation imaginable. As a result, they can thrive in almost any environment and are able to perform such tasks as transforming aromatic compounds, precipitating metals, and degrading oil. In short, microbes are the biological chemists of the natural world and they deserve much more recognition. Of course, it is hard to appreciate the invisible when visible species such as bison and Indian paintbrush are so prevalent. Yet Yellowstone itself provides an exception to this rule: The colors in its thermal springs show that there, at least, microbes dominate the landscape. What better environment could there be to teach us about the microbial world and its value as a natural resource?

Anna-Louise Resenbach Rutgers University New Brunswick, N.J.

1. E.O. Wilson, The Naturalist (Washington, D.C.: Island Press, 1994), 364.

2. V. Morell, "A River Doesn't Run through It," Science 273 (13 September 1996): 1496.

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