I’ve seen this in the Telegraph and the Guardian this week, as well as various places online, but it’s taken me a bit longer to post about it as I wanted to do some background reading on the subject. As my title says, this is about seaweed and its new role in the fight against malaria. Malaria is a parasite (genus Plasmodium) that has to spend part of its life inside a specific mosquito (anopheles if you want to know). If you’re bitten by one of these infected mosquitoes then the protist parasite can transfer to a human host where it multiples in the red blood cells leading to fevers and in severe cases death. There are various treatments for malaria available, the problem is that resistance to these drugs is now being demonstrated by the malaria parasite. Resistance can develop due to the rapid lifecycles of the parasite. As with humans, Plasmodium demonstrate genetic diversity and so some individuals may have a genetic makeup that, due to a beneficial mutation, confers resistance to a malarial-treatment drug. This Plasmodium is more likely to survive and pass on its genes to the next generation. This is survival of the fittest in action and over a relatively short period of time (compared to humans, can you imagine how long it would take this to happen in a human population?) a population could become immune to this antimalarial. This isn’t just happening with malaria, we see it with other infective agents – hence the rise of so-called ‘superbugs’ (such as MRSA) in hospitals that are resistant to many antibiotics. Although there are ways we can reduce the occurrence of resistant strains of infective agents by limiting antibiotic usage and ensuring correct dosage and use of antibiotics we can never get rid of them – they’re a fact of evolutionary predator-prey relationships. It’s a real-life example of the Red Queen Hypothesis. I’m not going to go into that hypothesis in detail here but is basically a theory to answer the question “why perform sexual reproduction when asexual reproduction is less hassle?” You may think the answer to this is obvious *ahem, thoughts back to the blog post, thank you* but biologists do puzzle over this question. Sexual reproduction is a bit of a hassle, energetically costly and sometimes downright dangerous: So, why do it? Well, the Red Queen Hypothesis suggests it could be due to the fact that sexual selection brings variation and it’s this variation that can lead to genetic defenses against parasites and predators. I always remember this theory as it’s cutely named after the character Lewis Carroll’s ‘Through the Looking Glass’ and her quote; “it takes all the running you can do, to keep in the same place”. So, resistance to drugs: we can’t beat it and therefore we need to fight it, constantly researching new drugs to fight out corner in this biological arms race. And that’s where seaweed comes in. A group at the Georgia Institute of Technology have found that chemicals, known as bromophycolides, produced from seaweeds have potential as antimalarials. They extracted these compounds, already known to fight fungal infections, from a species of tropical seaweed called Callophycus serratus. This is obviously of interest on the global stage, according to WHO figures over 750,000 people die each year from Malaysia, mainly in sub Saharan Africa, and new treatments are always welcomed. It’s also of interest to me as these bromophycolides contain bromine (hence the name!) which is also in the bromocarbons I study. There have already been suggestions that bromocarbons could be antimicrobial and anti-epiphytic (preventing smaller algae growing on the seaweed) and this could add weight to that idea if the bromine is contributing to the antifungal and malarial properties of the bromophycolides. It’s not a miracle-cure, some existing medicines work better, and it has still to be tested in mammals infected with malaria as opposed to ‘test-tube’ lab tests, but it’s a step towards a new tool in our fight against the disease.
This study was originally published in a 2009 article in the Journal of Organic Chemistry but is receiving news inches right now as it was recently discussed at the annual meeting of the American Association for the Advancement of Science (AAAS, the people behind Science magazine). Links to these below.
Reported by The Guardian and the Telegraph on Tuesday 22nd Feb 2011.
A good introduction to the Red Queen Theory [here]
AAAS (2011) AAAS Meeting. Science vol. 331 p. 996
picture source [here]
Lane AL, Stout EP, Lin AS, Prudhomme J, Le Roch K, Fairchild CR, Franzblau SG, Hay ME, Aalbersberg W, & Kubanek J (2009). Antimalarial bromophycolides J-Q from the Fijian red alga Callophycus serratus. The Journal of organic chemistry, 74 (7), 2736-42 PMID: 19271727