Camel Antibodies Used to Fight Trypanosomes

<p>Figure 1</p>

Belgian scientists say that small antibodies taken from the dromedary may prove useful in treating tropical parasites such as the African trypanosome, which causes sleeping sickness. Penetrating the dense, variable-specific surface glycoproteins that coat the organism, such antibodies may be able to zero in on conserved oligosaccharides hidden beneath. Serge Muyl-dermans and colleagues at the University of Brussels demonstrated its use as a diagnostic reagent for Trypanosoma brucei; by linking the antibody to an effector molecule, they showed that such an antibody could be used therapeutically. Muyldermans says that he thinks this holds great promise for the future.

Others who study tropical diseases doubt the wide applicability of such a technique. David Horn, lecturer at the London School of Hygiene and Tropical Medicine, writes in an E-mail, "The broad relevance of such reagents is questionable, since I'm not aware of other...

Arsenic and Old Wool

<p>Figure 2</p>

A wee drop of urine from a rare Scottish sheep offers new clues for arsenic metabolism and toxicity. Jörg Feldmann of Aberdeen University and colleagues at York University used chromatography and mass spectrometry to root out novel arsenic compounds from a rare wild sheep, the North Ronaldsay, which prefers seaweed to grass. Seaweed accumulates arsenic from sea-water, so the sheep's metabolites, they reasoned, might contain novel arsenic compounds.

A urine sample contained a thioorgan-oarsenate, a compound Feldmann says has not been found previously.2 "Our finding is surprising, but not actually unexpected," says Feldmann, "because arsenic has a high affinity for sulfur; in the body, arsenic ions bind to hydrogen sulfide groups in proteins, crippling important physiological functions." The formation of bonds between arsenic and sulfur atoms also helps break down arsenic-containing compounds. The metabolites will help researchers trace the biochemical path and may explain arsenic's toxicity and carcinogenicity.

Andrew Benson, professor of biology emeritus at University of California, San Diego, is unconvinced of the compound's novelty. "Francis Knowles and I have published on thioarsenoyl esters in plant and animal tissues for at least a decade; we use two-dimensional paper chromatographic analysis of whole tissues and miss nothing," he says. Feldmann retorts that mass spectrometry allows for more specific identification of individual compounds rather than simply indicating their presence, as in paper chromatography.

- David Bradley

"2-Dimethylarsinothioyl acetic acid identified in a biological sample: the first occurrence of a mammalian arsinothioyl metabolite," Feldmann J, Angew Chem Int Ed Engl Vol 43, 337-340 Jan. 13, 2004

Caspases for Life, not Death

Caspases, generally associated with cell death, may have a role at the very beginnings of life. Independent research from Bruce Hay's lab at California Institute of Technology3 and Hermann Steller's lab at Rockefeller University in New York 4 show caspases to be directly involved in Drosophila sperm individualization, the process during which spermatids differentiate and become single sperm cells. "It's been theorized before, but now we see exactly what the caspase molecules and pathways do," says Sharad Kumar, a cell-death expert at the Hanson Centre for Cancer Research at Adelaide University, South Africa.

During spermatogenesis, 64 individual sperm cells form within a cyst that was once a single cell. The caspases DRONC, DRICE, and ARK start the process of whittling away everything in the cyst that isn't sperm – mostly cytoplasm and organelles. "It's like a comb going through hair," says Hay.

Steller considers the caspase involvement as being a mirror image of traditional cell death. "It's virtual apoptosis," says Steller, who is now doing similar work in mice and hopes to eventually see his work lead to treatments for male infertility. "It's a whole different way of thinking about sperm formation."

- Sam Jaffe

"Multiple apoptotic caspase cascades are required in nonapoptotic roles for Drosophila spermatid individualization," Huh JR, PLoS Biol , 2004 Vol 2, 0043-53"Caspase activity and a specific cytochrome C are required for sperm differentiation in Drosophila," Arama E, Dev Cell , 2003 Vol 4, 687-97

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