-Caveat Lector- from - http://www.wired.com/news/technology/0,1282,49185,00.html?tw=wn20011224
Why Goldfish Might Turn Blue By Dermot McGrath 2:00 a.m. Dec. 24, 2001 PST Say goodbye to Birkenstock sandals and woolly jumpers -- tomorrow's eco-warrior will like nothing better than swimming naked in defense of cleaner oceans. That, at least, is the hope of researchers in Singapore, who are developing a breed of fish capable of detecting water pollutants by changing color. Scientists at the Department of Biological Sciences at Singapore's National University ( http://www.nus.edu.sg/ ) intend to produce commercially viable zebra fish that can be used as a simple, cheaper alternative to current pollutant-testing systems. Zebra fish are usually black and silver in color, but through genetic manipulation researchers have produced a few varieties that radiate green or red fluorescent color. Scientists have so far succeeded in isolating two types of gene promoters in the zebra fish -- an estrogen-inducible promoter and a stress-responsive promoter. These promoters -- the part of the gene that contains the information to turn the gene on or off -- have been used to drive the fluorescent color genes in transgenic zebra fish. A transgenic organism is one that contains genes from another species. According to researchers, such zebra fish will be able to respond to the presence of chemicals like estrogen, heavy metals and various toxins in water. "The most significant benefit of the biomonitoring fish is the possibility to develop an online system to monitor aquatic environment and water quality," project leader Zhiyuan Gong, associate professor in the Department of Biological Sciences at Singapore's National University, said. "Compared to conventional chemical measurement, the live fish can tell us the biological effect of the pollutants." The fish will immediately display the color depending on the type of environment the color has been specified for. Although only red and green colors have been produced in the zebra fish thus far, Gong and his team believe that they can produce up to as many as five colors, with each color indicating a different pollutant. The main advantages of such transgenic fish is that pollutants can be detected with one quick look, and the fish are also economical to breed and biodegradable. All these factors make them very suitable pollutant indicators, said Gong. Other researchers warn, however, that significant hurdles need to be overcome before transgenic fish can ever be commercially deployed as pollution indicators. "Any truly useful environmental monitoring tool should give us a signal which can be interpreted ecologically," said Donald Baird, a researcher with the environment group at the Institute of Aquaculture http://www.stir.ac.uk/Departments/NaturalSciences/Aquaculture/ ) in the University of Stirling in Scotland. "Molecular genetic signals such as color-changing fish are merely proxies for chemical analysis -- they tell us nothing about quantity of the substance present, merely that a threshold has been passed at a specific receptor site in the organism," he said. Baird believes that a more sensible approach would be to work with gene micro-arrays, which offer the possibility of simultaneously detecting a wide range of pollutants by examining the regulation of proteins. "This would be a cheap and non-destructive method of assessing chemical exposure. And it would not involve the use of live vertebrates which is now seen, quite rightly, as ethically untenable in routine monitoring and is gradually being phased out," he said. Gong estimated that it would take at least another year before the project moves beyond the experimental phase. "We can create such monitoring fish now using our existing techniques. However, we are still not sure how (sensitively) the fish can monitor environmental pollution and will need to do a lot of fine-tuning work," Gong conceded. Besides zebra fish, marine species such as the carp and goldfish can also be genetically engineered to display different fluorescent colors. The Singapore team is working toward producing fish that give off a different-colored glow depending on water temperature, which may lead to using fluorescent fish as temperature indicators. Richard Winn, associate professor of the Aquatic Biotechnology and Environmental Lab at the University of Georgia ( http://www.uga.edu/ ) said this is not the first time transgenic fish have been proposed as possible pollution indicators. "The concept of the environmental 'sentinel' is not new -- fish and other critters have been doing this for quite some time," he said. Winn is also skeptical that color-changing fish can offer a radical alternative to current pollution-monitoring techniques. "An important requirement of a test system is that it should provide an indication not only of the presence of a toxic chemical but also a graded response relative to the amount of chemical present," he said. "While it is valuable to know the organism has been exposed to compound ABC, it is often even more helpful to know that the organism was exposed to X amount of the compound, which produced the Y effect. Quite simply, any system that can provide a quantitative measure of a response is very valuable." Winn points out that even assuming the initial tests show the system works as planned, it may be a significant hurdle to actually receive permission to release the genetically modified fish in the wild. "There is some difference in opinion about the real or imagined impact of releasing transgenic fish into the environment," he said. "Depending upon the fish species and the transgenes used, the possible impacts could range from inconsequential to localized extinction of native species. This should be studied thoroughly before any release is considered." A study last year by researchers at Purdue University http://www.purdue.edu/UNS/html4ever/0002.Muir.trojan.html ) concluded that transgenic fish could present a significant threat to native wildlife, even to the point of extinction. Anne Kapuscinski, professor of Fisheries and Conservation Biology and founding director of the Institute for Social, Economic and Ecological Sustainability (ISEES - http://www.fw.umn.edu/ISEES/ ) at the University of Minnesota, agreed that a lot more research needed to be carried out to assess the potential risk of releasing transgenic fish into the environment. "In some fish species, adults of one gender or the other use color to attract mates and successfully reproduce. Genetically engineered changes in external color might interfere with the mate-attraction strategy in harmful ways or might have little or no impact," said Kapuscinski. She stressed the importance of conducting ecologically relevant bio-safety studies to credibly assess environmental risk at an early stage in the research and development of transgenic organisms. "So far, researchers have been waiting until much too late in the R&D process to enlist qualified fish biologists and ecologists to address the bio-safety questions," she said. <A HREF="http://www.ctrl.org/";>www.ctrl.org</A> DECLARATION & DISCLAIMER ========== CTRL is a discussion & informational exchange list. Proselytizing propagandic screeds are unwelcomed. Substance�not soap-boxing�please! These are sordid matters and 'conspiracy theory'�with its many half-truths, mis- directions and outright frauds�is used politically by different groups with major and minor effects spread throughout the spectrum of time and thought. That being said, CTRLgives no endorsement to the validity of posts, and always suggests to readers; be wary of what you read. 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