Feeding off fish pee

I was really here to feed on your urea.

Image courtesy of University of Aberdeen.

Ammonia is toxic to aquatic animals and yet there is ample evidence that sharks and their kin are attracted to it. Many experts have argued that sharks use ammonia to track down their prey and, while that might be true, a new study is now revealing evidence that sharks are capable of converting the toxin into a valuable resource with their gills.

The new work began when a previous study noted that ammonia can be actively taken up by shark gills and transformed into urea. While interesting on its own, the finding led the biochemists behind the new research to question whether the sharks were getting something more out of this conversion. After working through the chemistry associated with the process, they speculated that sharks were obtaining a net nitrogen gain from the ammonia uptake. This was intriguing because nitrogen has to be obtained by sharks through meat. Moreover, it is required not only for them to grow but also for them to manage the salt in their blood. When the researchers monitored what sharks did with ammonia laced waters in the lab, they were stunned to discover that the predators use it to cover 31% of their daily nitrogen demands and can thus get by on considerably less meat. You can read more in The Economist article that I wrote on this here.

Sticking around

The best medicines in the world cannot do much if the patients who need them do not take them as prescribed. This problem is particularly serious in rural areas where attempts to eliminate malaria are at work. One key drug, ivermectin, is excellent at killing off mosquitoes that feed on the blood of people taking it and can effectively create a firewall against malaria if everyone in an area is on it. The trouble is that ivermectin has an 18 hour half life in the body and needs to be taken daily by everyone for it to be effective at controlling malaria's movements. A solution has been badly needed and now a team is revealing that they have found one.

The researchers behind the new work have developed an oral, ultra–long-acting capsule that dissolves in the stomach and deploys a star-shaped structure that slowly releases ivermectin while assuming a position in the digestive tract that prevents it from passing into the intestines while still allowing food to get by. In tests run on pigs, the team found that the specially designed structures were able to release mosquito killing doses of ivermectin for two weeks at a time. Moreover, they suspect that with further engineering they can extend their drug release period to be several months. Furthermore, they suggest that there is a real potential for other drugs to be housed in their devices that could help medicate patients suffering from diseases that impair their ability to take drugs in the first place (like diabetes and Alzheimer's). You can read more in The Economist article that I wrote on this here.

You can read more in The Economist article that I wrote on this here.

Carnivorous origins

Wicked!

Image courtesy of Luis Lopez.

Palaeontologists have found a fossil that has all of the skeletal features which reveal it to be the great great grandparent of the sauropod dinosaurs like diplodocus, brachiosaurus and apatosaurus. The sauropods are well known for having been gentle giants. While they were absolutely enormous, their teeth make it clear that they never ate anything other than plants. We always figured that their ancestors were likely to have only eaten plants too and we were clearly wrong.

You do not have to be a palaeontologist to look at these teeth and know they were definitely not for chewing on leaves! It is a very cool finding that raises tonnes of questions like "what animals was this sauropod hunting" and "what forces drove its descendants to ultimately go vegetarian". You can read more in The Economist article that I wrote on this here.

Growing drugs to combat malaria

Sweet wormwood yields invaluable artemisinin, a compound that is highly effective against drug-resistant malaria. The trouble with artemisinin is that it is very expensive. A major part of the cost stems from the fact that wormwood is tricky to grow and artemisinin is challenging to extract from its tissues. Elimination of these challenges would make the antimalarial far more affordable and have the potential to save a lot of lives. Now researchers are reporting that they have found a way to do this by getting tobacco plants to produce artemisinin in copious amounts. 

The team behind the new work genetically engineered tobacco to produce artemisinin. This has been done before but the plants always yielded precious little of the compound and often did not grow very well. The team discovered a clever biochemical way around this. More importantly, they are reporting that the artemisinin produced by their engineered plants could be delivered orally to mice infected with malaria and that the drug proved very effective even when it was delivered while still encapsulated within the cells of the tobacco plant. 

You can read more in The Economist article that I wrote on this here.

Predatory pollination

Come closer dearie...

Image courtesy of Stefan Doetterl.

With its needle-like teeth and pitcher shape the South African parachute plant looks like it ought to be carnivorous. It very nearly is. Flies that enter fall into a pit of pollen and cannot get out until the pod they are in begins to wilt and the teeth holding them captive weaken. Yet many mysteries have remained. Flies are not known for their intelligence but it seems odd that they would be so willing to crawl into such a treacherous looking cavity.  Now a new study is revealing that the plant is releasing chemicals that dupe the insects into believing that their favourite prey are lying wounded within. 

You can read more in The Economist article that I wrote on this here.