New Scientist, Issue 3222, March 23, 2019

NEWS &TECHNOLOGY

another (Current Biology, doi.org/ fish passed off as more expensive c3m2). The use of names on ones. Deliberate mislabelling Net closing on the packaging such as snapper or across all is estimated skate, which cover up to 6o to involve billions of pounds of fake fish problem different species offish, also sales globally. doesn't help. "That average 30 per cent [of The study found just two all fish mislabelled] gives you Adam Vaughan being passed off as fatty . examples of deliberate no indication of whether it is "People know about it, the mislabelling among fish bearing deliberate or unintentional," says IS THAT really wild-caught, question is what do you do about its logo, with hoki swapped for Francis Neat of the MSC. But there Atlantic cod on your plate or, it," says Jaco Barendse at the MSC. hake, and for cod. are ways to get at the truth. "We as it turned out in a restaurant All the wrongly labelled The motivation for misleading can do the trace backs [through in Belgium, farmed ? bearing the MSC logo consumers is financial-cheaper the supply chain] and figure out On average, 30 per cent of fish were found to be white fish, where the substitution occurred, sold in shops and restaurants including cod and hake, which When trawling the shelves for and whether it is for financial globally is wrongly labelled, can be easily mistaken for one your favourite fish, beware gain or not," he says. with as much as half misdescribed Eco labels are just one way to in some places, according to a avoid being duped. Education 2018 review. Now it seems that also helps. Few customers of fish eco-labelling schemes could be and chip shops in the UK, for a possible fix to avoid fakes. example, know that , A study by the Marine which is often on the menu, is Stewardship Council (MSC) has another term for dogfish, a type found that less than 1 per cent of of that is overfished. seafood bearing its sustainability "People should know where mark was mislabelled. This was their fish was caught, how and determined using DNA tests on when, and what species it is. If 1402 products sold in 18 countries you don't know those things, you between 2009 and 2016. can't make informed choices on Consumers are often in the whether you can eat it with a clear dark over where their fish comes conscience," says Callum Roberts from, which can have serious at the University of York, UK. health and sustainability He also points to the limits implications. Some of the worst of DNA testing, which can tell examples have included toxic species apart but can't tell pufferfish being sold as monkfish whether a fish comes from a and endangered sustainable stock. •

to infection by bacteria and viruses triggering their destruction. to new sites in the body was greatly Smart bacteria that would be rapidly wiped out However, CD47 is also found on the reduced (bioRxiv, doi.org/c3k5). halt spread of elsewhere in the body. surface of healthy red blood cells, so The research shows that the The smart bacteria, created by injecting high levels of the antibody modified bacteria can be used to cancer in mice Sreyan Chowdhury at Columbia straight into the blood would be trigger body-wide immune system University in New York and his dangerous. By instead injecting the targeting of untreated tumours, says GENETICALLY modified "smart" colleagues take advantage of this, bacteria directly into tumours, high cancer biologist Graham Dellaire of bacteria injected into tumours can infecting a tumour and multiplying. levels of the antibody are produced Dalhousie University in Canada. shrink growths and trigger an immune Once the number of bacteria only where needed. "Harnessing this effect could response that stops cancer spreading, reaches a critical level, they are In tests in mice, several kinds of well be the key to curing metastatic tests in animals show. designed to self-destruct and release tumours shrank after being injected disease- the major cause of The engineered bacteria exploit an antibody in the heart of the with the smart bacteria. What's more, cancer-related death," he says. the vulnerability of solid tumours to cancerous growth. This antibody the growth of tumours elsewhere Whether this approach will work infections. This vulnerability comes then encourages the immune system in the body of the mice also slowed, in people remains to be seen, but about because tumours evolve all to attack the tumour. while the chances of cancer spreading Della ire points out that the live kinds of tricks for evading immune The team started with a harmless bacteria used to immunise against system attack, from physically strain of E. coli. This was engineered "Harnessing this could be TB, in the BCG vaccine, have long been keeping out immune cells to releasing to produce an antibody, which binds key to curing metastatic used to treat bladder cancer. This is chemicals that tell the cells not to to a called CD47 found on disease- the major cause also thought to work by triggering an attack. But this leaves tumours open the surface of some cancer cells, of cancer-related death" immune response. Michael Le Page •

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