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Goldfish ‘make alcohol to survive harsh conditions’
Goldfish and crucian carp can survive for long periods in oxygen-free water under ice.
Scientists uncover the secret of this unique ability

Goldfish and their wild relatives are able to produce alcohol to survive for days or even months at the bottom of frozen lakes or ponds. Now, scientists say they have unlocked their secret.

Humans and most other vertebrates die within a few minutes without oxygen. Goldfish and crucian carp, however, can survive for long periods in oxygen-free water under ice.

During this time, they convert anaerobically-produced lactic acid into ethanol, which diffuses across their gills into the surrounding water and avoids the fatal build up of lactic acid in the body.

New research in Scientific Reports shows that the muscles of these fish contain not one, but two sets of the proteins that are used to channel carbohydrates towards their breakdown within a cell’s mitochondria.

One set of these proteins appears to be similar to that in other species, but the second set is strongly activated by the absence of oxygen. It shows a mutation that allows metabolic substrates to be channelled to ethanol formation outside the mitochondria.

Genetic analysis suggests these two sets of proteins arose some eight million years ago, as part of a whole genome duplication event in a common ancestor of goldfish and crucian carp.

Lead author Dr Cathrine Elisabeth Fagernes said this allows crucian carp to avoid competition and preadtion by other species, as they are uniquely able to survive and exploit harsh environments.

“It’s no wonder then that the crucian carp’s cousin, the goldfish, is arguably one of the most resilient pets under human care,” she said.

Dr Michael Berenbrink at the University of Liverpool added: “During their time in oxygen-free water in ice-covered ponds, which can last for several months in their northern European habitat, blood alcohol concentrations in crucian carp can reach more than 50 mg per 100 millilitres, which is above the drink drive limit in these countries.

“However, this is still a much better situation than filling up with lactic acid, which is the metabolic end product for other vertebrates, including humans, when devoid of oxygen.”

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Scheme to protect wildlife and reduce flooding

News Story 1
 Natural England has announced a new scheme to improve flood protection, boost wildlife and create 160 hectares of new saltmarsh. The £6 million scheme in Lancashire will effectively unite the RSPB’s Hesketh Out Marsh Reserve and Natural England’s Ribble Estuary National Nature Reserve. The completed reserve will be the largest site of its kind in the north of England. 

News Shorts
Welfare event to discuss ethical dilemmas faced by vets

Students and ethics experts will host an event on the difficult moral challenges facing vets. Ethical issues, such as euthanasia and breeding animals for certain physical traits, will be discussed by prominent speakers including TV vet Emma Milne and RSPCA chief vet James Yeates. Other topics will include how to tackle suspected animal abuse and the extent of surgical intervention.

The conference will look at how these dilemmas affect the wellbeing of vets, and explore how to better prepare veterinary students for work. It will be held at the University of Edinburgh’s Easter Bush Campus from 30 September - 1 October 2017. Tickets can be purchased here.