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Deemed the delicious taste, umami is found naturally in foods such as aged cheeses, steak, seafood, and mushrooms, and as an additive, the sodium salt monosodium glutamate. The substance that subtly makes food taste better is one of the 20 common amino acids that make up proteins. Now, researchers have shown that taste cells bearing a combination of T1R1 and T1R3 (T1R1+3) G protein-coupled receptors are broadly tuned to respond to many amino acids, including umami's monosodium glutamate. Although the findings are intriguing, they don't conclude the search for umami taste receptors, says the National Institutes of Health's Nick Ryba, co-lead investigator with Charles Zuker at University of California, San Diego, on the report (G. Nelson et al., "An amino-acid taste receptor," Nature, 416:199-202, March 14, 2002). "The combination might have been of important evolutionary advantage since it provided the ability to detect amino acids—important components of protein-rich foods needed to survive, but there may be other amino acid receptors, as well," Ryba says. The researchers discovered the T1R1+3 combination by means of cell culture tests demonstrating how the different combinations of T1R taste receptors on cells responded to amino acids. The umami receptor work is part of Ryba's and Zuker's larger goal of understanding taste. In addition to these findings, they characterized a sweet receptor last year, which also requires T1R3 but in combination with T1R2, and earlier, they identified the T2R bitter family of receptors. "All along, we've wanted to understand how the brain interprets taste," Ryba says. "By defining the receptors, we're producing tools to start answering those questions." —Jennifer Fisher Wilson Eliminating Animal Tests in Drug Design? Radiation and toxins can snip DNA into pieces called micronuclei, found in immature red blood cells (reticulocytes). But the fact that reticulocytes are short-lived, rare, and rapidly plucked from the circulation by the spleen, has limited their utility as windows on DNA damage. Enter flow cytometry, which uses laser-activated dyes to separate the 10,000 or so reticulocytes among 6 million or so blood cells—only a few of which might have micronuclei. Because the telltale reticulocytes are a mixed bag, harboring different-sized micronuclei, identifying them against the backdrop of other cells and debris is challenging. Researchers at Litron Laboratories, in Rochester, NY, calibrate flow cytometry to be extra-sensitive to these cells with unusual helpers—rat reticulocytes infected with Plasmodium berghei. These cells contain the malaria parasite's genome, which is just about the size of the average human micronucleus and absorbs stains in much the same way. The cell rat stand-ins are scanned before the device probes human samples. "The malaria-infected samples represent external controls, allowing for more accurate detection than looking for rare events in human blood samples," explains Stephen Dertinger, director of research at Litron. The technique, which he calls "a new way to monitor a pinprick's worth of human peripheral blood for DNA damage," is described in an upcoming issue of Mutation Research. The micronucleus assay may replace animal testing in drug development. —Ricki Lewis The Money-Making Academy Erica P. Johnson Commercialization of academic research jumped in value by more than 46% in 2000, generating more than $1.26 billion in adjusted gross licensing fees for US and Canadian universities, research institutes, and hospitals. A survey of 190 organizations conducted by the Association of University Technology Managers (AUTM) found that universities created more than 450 new companies and made 347 new products based on academic discoveries commercially available in 2000 (AUTM Licensing Survey, FY2000, Association of University Technology Managers, www.autm.net). Nearly 21,000 inventions are actively under license, although only 125, or 0.6%, generate more than $1 million in royalties. The University of California system generated more revenue than any other: $261 million in fees from 781 licenses. Those universities also launched 26 start-up companies. Columbia University pulled in more than $138 million from 143 licenses. The University of Wisconsin, Madison, which licenses human embryonic stem cells for research, generated nearly $23 million from multiple discoveries. "Technology licensing provides the return on investment for all the taxpayer dollars given to support research," says Janet Scholz, AUTM president and senior technology development manager at the University of Manitoba. "We have fabulous research facilities and good, creative people. Technology licensing is the way to benefit society for all that good work." —Ted Agres Dollars Over Discoveries? Erica P. Johnson US and European patents could boost the cost of genetic screening for consumers and researchers, according to a report from the Center for Bioethics at the University of Pennsylvania. Clinical trials rely on testing volume, and many laboratories simply can't pay to use the sequences involved in the screening tests, says Jon Merz, assistant professor of bioethics at the University of Pennsylvania and coauthor of the gene patent report (J.F. Merz et al., "Diagnostic testing fails the test," Nature, 415:477, Feb. 7, 2002). Labs quickly adopt the new tests before they are patented, and when the patent finally is issued and payment is requested, scientists may have to discontinue years of work because they cannot pay. Merz says that patents on genes could create serious impediments to genetic testing and treatment for years to come. But Michael Werner, vice president of the US Biotechnology Industry Organization, defends patent practices: "I think the whole patent system has worked quite efficiently." The Institut Curie in Paris has challenged the European patent rights to BRCA1 and BRCA2 granted to Myriad Genetics Inc. in Salt Lake City. Another company, Bio-Rad Laboratories of Hercules, Calif., owns the patent for the test that detects the HFE gene, associated with hemochromatosis (See "A Case Too Soon for Genetic Testing?"). —Hal Cohen Sex, Flies, and Seminal Proteins It appears that female Drosophila may be having killer sex each time they mate. Seminal proteins have been found to shorten the lifespan of female fruit flies, according to a research review by Mariana Wolfner, professor of developmental biology at Cornell University (M.F. Wolfner, "The gifts that keep on giving: physiological function and evolutionary dynamic of male seminal proteins in Drosophila," Heredity, 88:89, February 2002). These proteins made in the male's accessory gland can, among other things, stimulate female ovulation, reduce their receptivity to mating, facilitate sperm storage, and reduce the female's lifespan. Wolfner says the decrease in lifespan "is a small decrease, but definitely there," and is attributed in part to the energetic demands from increased ovulation. As mating decreases a female's longevity, sperm storage becomes particularly advantageous because mating occurs less frequently. Several secreted accessory gland proteins (Acps) are not entirely essential for the sperm storage but help the process. Wolfner says that without Acps changes in egg production, egg-laying becomes impossible. —Hal Cohen Women, and The Scent of A Man For the first time, University of Chicago researchers have shown that humans, in this case women, can distinguish differences in odor down to a single gene (S. Jacob et al., "Paternally inherited HLA alleles are associated with women's choices of male odor," Nature Genetics, 30:175-9, February 2002). They also determined that female study participants preferred the scents of certain men, thanks to immune-response genes inherited from their fathers. Women rated human and nonhuman scents for familiarity, intensity, pleasantness, and spiciness, although few detected them as human odors. The study's goal was to determine what scent the women wanted to be constantly near. The researchers then compared the sequence of the human leukocyte antigen (HLA) gene, which determines self from nonself, of women participants to their parents and males, who had turned in T-shirts they slept in for two consecutive nights. Women preferred manly scents that had an intermediate level of difference in HLA sequence as compared to their own. Past studies from the Chicago group showed that marriages were not random with respect to HLA sequence. These lines of evidence point to HLA-derived odors or pheromones as one mechanism for understanding human social behavior, like avoiding inbreeding, and perhaps mate selection, notes Martha K. McClintock, director of Chicago's Institute for Mind and Body, and the article's senior author. "This is the first study to show an inherited preference in humans," says McClintock. "The basis for the choice is genetic, and it's inherited paternally." —kykreeger@aol.com

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