MycoRant

The following thread (names have been removed) has recently appeared on the Google group for DIY Bio (that’s do it yourself biology). Feel free to mosey on over and sign up to chime in, or to get involved with many of the other projects/discussions going on over there.

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TOPIC: Mushroom test kits
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Has anyone ever heard of a test kit for identifying poisonous mushrooms? I was just thinking that would be a really interesting/useful thing to have, and I didn’t find one looking through Google. That may have to do with the wide range of toxins that mushrooms can produce (at least 13 according to Wikipedia), which would make the kit pretty complex. Has anyone else ever thought about doing this?

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In the same way that software has to be written specially for life-critical applications (nuclear power plants, heart-lung machines, etc.), I doubt anyone would be willing to open themselves up to the kind of liability involved in that sort of thing, particularly for such a small market.

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You would need antibody detection for detecting compounds, but someday there should be a microfluidic chip that does PCR and sequencing… you could place a tissue sample on the chip in a small plastic mortar, grind with a pestle and have the masticated tissue enter into the chip device at the bottom.

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What about spectrophotometers? In some cases, compounds absorb a very particular wavelength of light, making for a distinct range in the spectrum. Antibodies sound like a pain in the ass for this application.

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This can most likely be used to test for the typical poisonous compounds found in mushrooms as well as any other psychotropic substances (ibotenic acid, psilocybin, psilocin, etc.), however the active chemicals aren’t always well-known, especially in the cases of rarer or simply less-known mushrooms. If mycology is an interest, a good field guide, a microscope, and experience are the best tools for determining what mushrooms are what, and field guides can, at the very least, tell you if a mushroom is edible or not. Generally poisonous mushrooms just cause a few days of gastrointestinal upset (although explosive diarrhea isn’t really an activity I’d like to spend a few days with), but there are also a good amount (and usually they are quite distinctive) that are common and can cause massive liver and kidney failure. Microscopy is really the end-all be-all of identification, by examining spore and gill structure.

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Not only that, but antibodies typically are most effective on other proteins and mushroom toxins are small, organic compounds:  not very immunogenic.  Also, there isn’t one single class of toxins in mushrooms, rather a number of different types of toxins.  See, for example: http://americanmushrooms.com/toxicms.htm

Spectrophotometers would work,  but would likely need a Mass Spec and not distinguishable by simple Vis/UV spec without extensive sample prep/methods development. Reading a good book or three, taking a class and knowing what you’re picking is still the best route.  And really not difficult at all to master.

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That link was pretty interesting, up until the author listed psilocybin as a toxin…it’s toxicity is much less than that of caffeine and the only negative physical effects (nearly all the effects are in the mind) are GI upset, etc.

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here is the conversation I had with a professor almost a year ago:

Dr. xxxxxx,

For our Cell Bio recitation we are investigating the Japanese puffer fish “Fugu” toxin, tetrodotoxin (blocks neural sodium ion channels, inhibiting action potential propogation,) and have been asked to “develop” a treatment for poisoning.

According to most websites, the current treatment is activated charcoal and maybe administration of acetylcholinesterase-inhibitor to increase the likelihood of muscular excitation (pulmonary is the main concern).

In my teams’s research, we came upon a journal published by some folks at USAMRIID (U.S. Army Medical Research Institute of Infectious Diseases) that developed antibodies which prevented mortality when administered before and after lethal amounts of toxin were administered (6 of 6 poisoned mice survived with antibody treatment)

What I don’t quite understand is the materials and methods of the attached journal article (PDF format)… it mentions that the tetrodotoxin (TTX) was conjugated to Keyhole limpet hemocyanin and to bovine serum albumin, and that female mice were immunized using the conjugates. Does that mean that the end-product antibodies are only effective at binding (or binding and catabolizing?) protein-conjugated TTX, or are the antibodies also effective against molecular TTX?

As I said, attached is the full journal article, and below is a link to the quick abstract… either are quick reads.

http://www.medscape.com/medline/abstract/8585093?src=emed_ckb_ref_0

Thanks a lot!

and his response:

Hi yyyyyyy,

The tetrodotoxin was described as a *low molecular weight* neurotoxin (and has a mass of 319.27 g mol-1). Past experimentation with low molecular weight molecules resulted in almost no immune response.  Turns out the SIZE was critical.  There appears to be a minimum threshold mw that the immunogen must be in order for it to stimulate a reasonable response.  Small molecules that are intended to be used to stimulate an immune response are called “haptens”.  The attachment (called conjugation) of the hapten, tetrodotoxin, to either KLH or BSA (referred to as “carriers”) is simply giving the overall conjugate enough size to stimulate a response.  There will now be antibodies produced that are specific only for the TTX (the hapten) and other antibodies specific for many other epitopes on the large “carrier” molecule (KLH or BSA).  Responses against KLH or BSA would be irrelevant to the response against (TTX), i.e., would not affect nor interfere with the anti-TTX response.

Hope this helps

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How about an in field ames test kit? It would not be immediate, but it could be quite effective, especially if there was some way to use mammalian cells.

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I’ve got an idea for a 100% accurate, field-expedient mushroom testing procedure that gives results as fast as you could possibly want them. The only drawbacks are that it requires putting up with Cub Scouts and, occasionally, hiding bodies.  If anyone is interested I can email
you details off list.

Tags: identification, mushroom poisoning