Glow sushi!

By Siouxsie Wiles 18/03/2012 5

When I first heard of this (and thanks to the lovely Alan Huett for the heads up), I immediately thought it was due to the common bioluminescent bacteria often found on fish and which can show themselves if said fish is left too long before eating.

It turns out to be sushi made using genetically modified fluorescent zebrafish (GloFish®). Sold in the USA by Yorktown Technologies, GloFish® available are currently available in five colours (Starfire Red®, Electric Green®, Sunburst Orange®, Cosmic Blueâ„¢ and Galactic Purpleâ„¢). They were developed by incorporating genes for fluorescent proteins, originally derived from jellyfish or sea coral, into zebrafsh embryos. While Yorktown advise that, as with other ornamental fish, GloFish® are not intended for human consumption, Cooking with GloFish offers suggestions* on how to prepare such delicacies as “stop and glow nigirizushi” and “kryptonite roll”.

While GloFish® are some of the first genetically modified animals to become publicly available as a pet, their origins aren’t in the ornamental fish trade but as a scientific tool. Fluorescent zebrafish are commonly used by scientists to study everything from gene expression and vertebrate development, to wound healing, cancer and cardiovascular disease. The Biotechnology Learning Hub has loads of information on the use of zebrafish by Associate Professor Don Love and his team at Auckland University to study the inherited disease Duchenne muscular dystrophy. They comment on how zebrafish mutants are made, how they are looked after in the lab and the ethics of using them as a model organism.

As Saturday the 24th March is World TB Day, I’ll finish off with a little round up of how the zebrafish is being used in research into Mycobacterium tuberculosis, the agent of TB. I’ve blogged about why TB is such a big problem before, but just to remind you, it is estimated that a third of the world’s population are latently infected, it kills 4,500 people every day and we are now facing strains that are resistant to all currently used antibiotics.

Zebrafish are naturally susceptible to M. marinum, a close relative of M. tuberculosis. M. marinum is also an opportunistic pathogen of man, causing the wonderfully named ‘fish-fancier’s finger’ or ‘fish-tank disease’. Unlike M. tuberculosis, M. marinum is a hazard group 2 organism, meaning it doesn’t require a specialised biosafety level 3 lab to work with. Prof Lalita Ramakrishnan and her team at the University of Washington have shown that M. marinum actively recruits and infects macrophages, using them to aid dissemination. This is forcing a complete rethink of the role of macrophages in human TB infection. Meanwhile Dr David Tobin at Duke University Medical Centre are using zebrafish to look for host genes involved in susceptibility to TB.

* Fluorescent proteins are denatured at high temperatures so best not to cook!

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