Tag Archives: toxin

The bacteria in your belly Pt. 3 – Disrupting the balance

ResearchBlogging.orgIn the previous two posts we have established how the microbiome is established and then the pressures the host puts on it to maintain a balance between the required functions and the commensal bacteria providing them. In this post I want to look a little deeper at what happens if this balance is disturbed or never properly forms at all. Continue reading


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The Wednesday Post (1/9/10)


Enough of vaccines for a moment. I want to talk about frogs, frogs and antimicrobial agents.

Normally I find it hard to remain interested in anything with a central nervous system but recently two frog related stories have caught my eye. First was this little dude.

Are you kidding me, that thing is tiny. Sometimes its hard to separate what ‘should be big’ like animals with skeletons and brains etc from what ‘should be small’ – anything that can be measured by ‘the number that could fit on the end of a pencil’. It turns out we have known about them for a while but they were incorrectly classified by a museum who thought they were juveniles of a different species, easy mistake to make I guess. They live in the pitchers of the plant Nepenthes ampullaria and the tadpoles develop in the watery discharge inside the pitcher until they can climb out. Awesome.

As interesting as this little guy is it’s hardly a disease or even remotely disease-y enough on its own. I only mention it was the first of two frog stories that caught my eye.

At a meeting of the American Chemical Society last week a group of researchers from the United Arab Emirates University presented some data showing they had collected and analysed frog skin compounds that elicited an anti-microbial effects from a wide range of species. They have been able to isolate over 200 novel compounds in only a year, which suggests that there are hundreds more compounds to find.

Specifically what they found was a number of potent anti-microbial peptides. Most organisms produce something of this nature and in fact humans produce our own AMP’s, but, human pathogens evolve to evade human defences so the sudden potential availability of new AMP’s may help in the production of new drugs for the treatment of human diseases.

The next step is to take these new compounds as they are identified and check for toxicity to human cells and to make any changes that can mitigate toxicity without affecting the anti-microbial potency. With some compounds already showing promise in regards to bacterial species like the infamous ‘Golden Staph’ frog based therapies might not be too far fetched and with any luck not too far away either.

In the long run the problem with developing these therapies might be us as it’s estimated that many frogs species are becoming extinct and humans are certainly responsible for some of this.

Unless you’re not a nature and biology lover already perhaps this provides a good enough reason for you to protect the environment. As clever as we are at experiments and drug design nature has undoubtedly done it somewhere before. Nature’s experiments are better designed and take place over a longer time frame.

So protect the frogs, newts, salamanders and all animal life if only on the off chance they might one day save your life.


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Blaustein, A., & Kiesecker, J. (2002). Complexity in conservation: lessons from the global decline of amphibian populations Ecology Letters, 5 (4), 597-608 DOI: 10.1046/j.1461-0248.2002.00352.x
Smet, K., & Contreras, R. (2005). Human Antimicrobial Peptides: Defensins, Cathelicidins and Histatins Biotechnology Letters, 27 (18), 1337-1347 DOI: 10.1007/s10529-005-0936-5


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Vaccine styles for specific diseases

ResearchBlogging.orgThomas has started a series on vaccines and disease and I thought it was such a great idea that I would hijack it, kind of.

While Thomas talks about specific vaccines and their impact on certain diseases I thought I would cover some more general topics under the umbrella of vaccines. So let me present my own vaccine mini-series to supplement Thomas’ – Vaccines: how they are made?, how do they work?, and why we can’t rely on therapeutics alone in the fight against disease?

This week we will look at how some of the common ways vaccines are made. This has been a topic of interest to me for a while, ever since I heard someone from the (miss-information spreading, anti-vaccination supporting) Australian Vaccination Network giving a talk at a Vegan festival about the dangers of vaccines. In front of a room full of people this woman proudly proclaimed that the polio vaccine is made in monkey brains and if you let your child take the oral polio vaccine they will be eating monkey brain. I was dragged away before I could ‘politely question’ the woman by my wife, who had declared a science free weekend :).

Anyway, the point is that this woman was talking crap. There would be no logic to making the vaccine in monkey brains, how many monkey brains does she think evil scientists can get their hands on? All the monkey heads I get my hands on are used in the construction of two headed monkey slaves. I wouldn’t waste them on vaccine production.

I can only assume a two-headed monkey would complete my typing faster than a lazy, stupid one-headed monkey <http://commons.wikimedia.org/wiki/File:Monkey-typing.jpg&gt;

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Scientific Casualties – Infectious disease research can be life threatening


Before this weeks post I would like to make an announcement. At this stage I am claiming victory in the debate. You can check out the results on the poll itself here. First I would like to thank myself for putting up such an amazing argument. I would also like to thank Thomas for putting up an insufficient fight, I’ll save some cake for you buddy. I would like to thank my wife and our dogs whose love and support get me throu………..<music plays me off stage>.

I don’t want to sound like I’m brave or a hero or anything but each and every day I, alongside my lab-mates aka ‘the league of extraordinary scientists’, stare down pathogens like S. pneumoniae, E. coli, S. flexneri and L. monocytogenes. We go into battle to try and work out how it is that we can tackle these bad guys on a global scale, developing vaccines and anti-microbials or simply understanding their weaknesses better.

So how do we protect ourselves from these harbingers of death in the lab? A gown, gloves and glasses when appropriate and ethanol on everything all the time to ensure it’s sterilised regularly. Really doesn’t seem like much of a barrier when I think about it.

Thomas wearing his lab coat to protect himself from his work… Thomas. Are you in a bar? Bad Thomas!

In some cases we specifically work on weakened strains to help protect ourselves further but we do rely heavily on our ability to handle these bacteria carefully and with common sense. However, despite all the precautions we take in the lab I’m reasonably sure some of us would be carrying the bugs we work on. Continue reading


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Puffer-fish poisoning – Poison, poison… Tasty fish!

As I’ve said before, the definition of disease is fairly open and, in a sense, poisoning is a disease. Does it really matter whether a toxin is produced by something that’s in the body as opposed to outside the body? Perhaps. I don’t know. I don’t really care. Here’s this week’s article.

For a long time, the Japanese have known that people who ate puffer-fish liver would, on a somewhat regular basis, become paralysed, stop breathing and die. This became such a widespread problem that Japan banned the sale of puffer-fish liver in restaurants and markets in 1983. Despite this, people have not stopped eating it. In fact from 1997 to 2007, 470 people were admitted into hospital for puffer-fish poisoning, 30 of whom died. People eat these livers thinking they have special ways of neutralising the toxin. Experimentally (as seen as above) these ways do not work.

OK, Japan. Come here a minute, I just want to talk to you. Now I enjoy food. I’ll eat deliciously deep-fried food that will sever a good couple of months off my life. I’ll go on the occasional bender and increase my risk of cirrhosis. Hell, I’ve eaten at McDonald’s when it wasn’t even necessary. But really, Japan, there is no fish innard tasty enough to warrant risking dying a slow, frightening death by suffocation.

Junk food and alcohol. Probably still not as bad as puffer-fish liver... maybe. (Picture taken by uhh... someone, I don't remember)

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Tetanus – the eternal struggle between Man and Rusty Nail

This article has been published previously in a 2006 edition of On Dit (the University of Adelaide student magazine), but like the media bastards they are, they edited and gutted it to nothing. Here’s the full article as intended. Also, I did write it as an undergrad so please forgive any mistakes, factual, grammatical or otherwise.

Small Nail_2
Picture taken by Thomas Tu

Holy stinking faeces, Batman!

You might wonder why you need to get a tetanus shot whenever you impale yourself with a stick or rub manure into your newly-acquired open wound. It’s because ~100 000 people die every year from tetanus every year, you dirty coprophiliac! OK, that’s misleading; most deaths are newly-born babies due to unsanitary birthing conditions, but even healthy adults can still die if left untreated. Continue reading


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