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Timber Rattlesnake (Crotalus horridus)

The magnificent timber rattlesnake (Crotalus horridus) is a venomous pit viper which lives throughout the populated northeastern portion of the United States of America from Texas to New England.  Ferrebeekeeper has considerable affection for the dangerous reptile (at an appropriate distance, of course!) and has already referenced the timber rattler as a metaphor for national liberty and, strangely, as a point of comparison for a large sports venue.  But timber rattlesnakes are so much more.  They were one of the first new world animals to utterly fascinate and horrify European colonizers. In the colonial period a serious rattlesnake bite was a death sentence (although we now have anti-venom) but the original natural scientists did not appreciate how complicated and remarkable the snakes were in other aspects.

As I write this, it is November and the rattlesnakes are all abed for the winter.  Because they live in areas with harsh winters, timber rattlesnakes spend more than 7 months a year in hibernation.  Large numbers will nest together in a community den—sometimes together with other snakes such as blacksnakes and copperheads.  The den is usually a rocky chasm which extends deep beneath the frost line, and rattlesnakes may travel many miles to reach their hibernation den (a bi-annual journey which puts the snakes at great risk from predators and from cars).

Because of their large and diverse territory, timber rattlesnakes come in different sizes, colorations, and even have different venom types.  The average timber rattlesnake grows to 100 cm (39 in) long and weighs between a half kilo and a kilogram (1 to 2 pounds).  Much larger specimens are known (although there is considerable ridiculous dispute about the upper ranges of rattlesnake size).  Female timer rattlesnakes are viviparous although, unlike mammals, rattelsankes protect their eggs within their bodies until they hatch.  Rattlesnakes give birth to litters of 6-10 fully formed, fully poisonous little baby snakes, but they can only reproduce every few years since the experience is very hard on them.

Like catfishes, timber rattlesnakes have senses which we do not possess.  Pit vipers are so named because they have nostril like spots (pits!) on the side of the head which they use to perceive infrared electromagnetic radiation. These pits are quite sensitive and act as third eyes.  Snakes (and many other animals) also have special auxiliary olfactory sense organs called Jacobson’s organs which are extremely sensitive to various smells/tastes.  Snakes characteristically pick up chemical traces with their tongues and waft these smells before their Jacobson’s organs in the characteristic tongue-flicking which is such a trademark.

Of course rattlesnakes are not just sensitive—they are also expressive.  Among all other snakes they are distinctive in that they have a specialized structure at the end of their tail for making a warning noise. Rattlesnake rattles consists of hollow button-like segments which produce a distinctive buzzing when the snakes vibrate their tails.  As a rattlesnake sheds her skin (every few months), she adds a new button to her tail.  Rattles however are not perfect records of how many times snakes have shed their skin—sometimes buttons get knocked off, or just become brittle and fall away.  The rattle has a high frequency and varies in loudness between 60-80 decibels from a distance of one meter (which falls somewhere between the noise level of an animated conversation and a garbage disposal).  Ironically, the rattlesnakes themselves are deaf.

Timber Rattlesnakes can be masters of camouflage

The venom of timber rattlesnakes varies in toxicity depending on the subspecies, but the most toxic rattlesnakes are extremely venomous.  Type A venom is a neurotoxin whereas type B venom is hemorrhagic and proteolytic (which is to say it causes bleeding and breaks down fundamental body proteins).  Type C venom is largely harmless.  In Arkansas and Louisiana, timeber rattlesnakes are particularly dangerous because cross-breeding has resulted in snakes which have type AB venom (yikes!). To a lesser extent rattlesnake venom also contains esoteric myotoxins which rapidly kill muscle tissues.  This deadly cocktail of different venoms is of great interest to pharmacologists who continue to study the various toxic proteins to tease out potential medicines.

watch?v=ZIrQet2LPUg

Fortunately timber rattlesnakes are good-natured and do not generally bite without much posturing, rattling, hissing, and feinting.  They keep their retractable fangs folded up in a mouth sheath when not in use and they are capable of varying the amount of venom they inject based on how they are feeling.  It is best not to antagonize rattlesnakes lest they abandon their amiable disposition.

Timber rattlesnakes are gifted ambush predators which particularly prey on small mammals such as squirrels, chipmunks, mice, and other rodents, but they also eat amphibians and birds.  In turn rattlesnakes  are preyed on by owls, hawks, bobcats, foxes, crows, skunks, and even turkeys! Rattlesnakes are an important part of the woodland ecosystem, but they face serious threats from habitat loss and traffic (cars being indifferent to the protective poison of snakes).

C. horridus eating a chipmunk by unhinging its jaw (Photo taken by Kevin Ostanek)

Not only are many rattlesnakes killed by traffic, they must also face persecution. Many are killed by angry villagers carrying torches and pitchforks.  Gawping Texans take this to a particular extreme and organize great “rattlesnake round-ups” where huge numbers of rattlesnakes are wantonly tormented and killed for no particular reason (except perhaps to demonstrate a hatred of the world and its creatures).  This is particularly sad since rattlesnakes, like whales, or elephants (or ourselves) are k-selected animals.  They live long but reproduce slowly, which makes them especially vulnerable to population crashes.

If, by some appalling circumstance, you have read this far while a timber rattlesnake sits nearby buzzing its tail, you should run away from the snake!  Do not attempt to molest it.  If you feel threatened, call animal control.  The timber rattlesnake is already vanishing from great expanses of its territory.  It would be a shame if this beautiful and fearsome serpent were to slip away from the earth.

Timber Rattlesnake by Hazel Galloway

Marbled cone snail (Conus marmoreus) by shadowshador

In olden days, in Australia, young healthy beachgoers were sometimes found lying on the shore dead.  Their bodies gave no evidence of trauma, indeed they had not even gone into the water. Something just struck them down as they sauntered along the beach.  It was not until 1936 that the mysterious killer was finally revealed when a beachcomber picked up a colorful snail and began to scrape its shell with his knife.  The unlucky young man uttered a cry as the snail somehow pricked him.  He then fell down, went into a coma, and shortly died.  Because of witness testimony, coroners knew what to look for and they removed a tiny poisonous harpoon the size of a small hair from the victim’s hand. The culprit turned out to be a cone snail, one of a diverse group of deadly gastropod mollusks.

The Geographic Cone Snail (Conus geographus) shows its siphon and proboscis. This snail is also humorously called “the cigarette snail” since if one stings you, you allegedly have time for one cigarette before dying.

There are over 600 different species of snail within the genus Conus and they are all poisonous predatory hunters.  The smaller cone snails hunt tiny mollusks and worms but the larger snails feed on fish, which need to be quickly subdued (so that they do not injure the snail by thrashing about) and then consumed with equal dispatch so that other ocean creatures do not steal the meal.  In order to quickly dispatch their prey (and defend against larger predators), Cone snails have a sophisticated weapon–a modified radula tooth which directly injects potent venom by means of a tiny harpoon-like “dart.”  The snail finds prey by carefully testing/sniffing the water with a siphon.  It then stretches out a long flexible proboscis and fires the disposable hollow radula tooth (filled with venom) into the prey by means of a powerful muscle contraction.  Below is a shocking film which shows a cone snail killing and consuming a clown fish by such means.  It is not for the faint of heart!

Although cone snails are obviously alarming to divers and shell collectors (particularly in warm tropical reefs where the large poisonous specimens live), the potent cocktail of neurotoxins utilized by the creatures is of great interest to pharmaceutical researchers.  Since each species of cone snail has a very large number of different “conotoxins” in its poison, scientists have been struggling to catalog and understand the dangerous mixtures. These conotoxins are generally peptides which interfere with the ability of nerve cells to communicate with one another.  Not only might such chemicals provide the key to curing neurodegenerative diseases and brain cancers,  conotoxin research is now the most promising avenue towards effective medications to deal with certain sorts of chronic pain.

A lovely diagram of Conotoxin Peptides from “The Journal of Neuroscience”

Unfortunately all of this research has not provided any effective antitoxins for victims of cone snail stings.  If a person is fully darted by one of the large poisonous specimens, their best hope is to go on a ventilator until their body expunges all of the poison—an uncertain prospect at best.

A Tiny Sample of the Exquisite Variety of Cone Snail Shells (Photo by Pet/Wikimedia Commons)

Many cone snails have beautiful colorful shells marked with vivid abstract patterns.  Some of the most valuable shells ever came from cone snails–which continue to fascinate conchologists and shell collectors.  Even today divers and beach combers are sometimes overwhelmed by the beauty of cone snails and reach out to grab the lovely creatures.  Hopefully this article has convinced you that doing so is a very bad idea.

The Common Monkshood (Aconitum napellus)

This week’s theme on Ferrebeekeeper is “Flowers of the Underworld.” So far we have featured a ghostly-looking flower which is actually edible and a demonic looking flower which is actually medicinal—hardly plants from the depths of hell.  Today therefore we are proceeding in a scarier direction and featuring a flower of delicate beauty…which is profoundly poisonous.  Aconitum is a genus of about 300 flowers belonging to the buttercup family (a family of flowering plants, notable for the number of toxic plants therein, which has been extant since the Cretaceous). The aconites are hardy perennial flowers which grow throughout the Northern Hemisphere but largely prefer mountain meadows and rich cool forests.  The plants have many common names which range from whimsical to hair-raising: “blue rocket”, “monkshood”, “wolfsbane”, “woman’s bane”, “devil’s helmet”, “mourning bride”, “Hecateis herba” (which means “the herb of Hecate”, to whom the aconites are sacred) and so on.  All aconite plants are extremely toxic.  You should not eat them, touch them, or even write about them without taking precautions. Seriously—Pliny the Elder (absurdly) wrote that the smell of aconite could kill a mouse from a substantial distance! When something is so toxic that it hoodwinked the greatest naturalist of the Roman era, you know it is really a fraught topic (although, frankly, Pliny made some other errors as well).

Aconite plants have dark green leaves in a spiral pattern and a radish-like root.  In the wild they live in rich soils, preferring those which are moist but well drained, however they can be cultivated easily in a variety of locations.  The real glories of aconites are their flowers, which are lovely but difficult to describe–the tall upright stems support numerous blossoms each of which has five sepals.  The posterior sepal is in the shape of a cylindrical helmet or hood from classical antiquity (the source of many of the aconites’ common names).  The most common aconite in Europe is the common monkshood (Aconitum napellus) which is known from its brilliant blue-purple flowers and from endless mystery novels, but other species look somewhat different.  For example, the yellow wolfsbane (Aconitum anthora) lives in the Alps and bears pretty yellow blossoms.

The Yellow Wolfbane (Aconitum anthora)

Since I am an avid flower gardener and do not have children, dogs, or livestock, I decided to plant monkshood in my old garden.  Unfortunately, for all of their reputed hardiness, the flowers were no match for the toxic soil and the dreadful machinations of the Norway maple.  Perhaps their failure was a good thing.  Because aconites are so toxic, I became prey to paranoid thoughts that agile children would somehow steal into my (walled) garden and eat the (unappealing tasting) plants.

The flower I planted--Bicolor Monkshood (Aconitum x cammarum, var. Eleanor & Stainless Steel)

My paranoia was not groundless–aconites contain virulent neurotoxins. Inchem.org describes the mechanism of aconite poisoning in the typically bland language of pharmacology stating, “Aconite alkaloids activate the sodium channel and have widespread effects on the excitable membranes of cardiac, neural and muscle tissue.” In translation this means that alkaloid compounds found in all parts of the plant (but particularly the root) are potent neurotoxins which disrupt neural and nerve-to-muscle signals and usually prove fatal by stopping the heart. Because it is so dangerous, aconite has a substantial place in history.  Chinese soldiers used the poison for their arrows and Greeks poured it into water supplies as an early form of bio-warfare. The roots were most infamous as a gastronomically administered stealth poison. Emperor Claudius was probably killed by aconite poisoning, as too was Emperor John I Tzimisces.  These emperors were joined over the years by numerous other victims from all walks of life.  Aconite has also been used as a medicine (and still is part of Chinese traditional homeopathy), but since it is so easy to kill patients with a slight overdose, Western doctors abandoned compounds derived from the plant as soon as other subtler neurological drugs were found.

Aconitum ferox (Dr. J. Bhunia)

Aconite flowers have an equally dramatic place in myth and literature.  According to Ovid’s Metamorphoses, aconite plants first came into the world when Hercules dragged Cerberus, the monstrous canine offspring of Echidna, up from the underworld into the world of life.   The poison drool–or “lip-froth” as it is written in my translation–fell from the hellhound’s three gnashing mouths, landed on the ground in Scythia, and transformed into aconite flowers. Ovid recounts the tale as an aside while recounting how the poison was a particular favorite of Medea (the citation is Ovid, Metamorphoses 7. 412 if you want to read the dramatic passage for yourself).

Medea (Anthony Frederick Augustus Sandys, painted 1866-68)

It was not just classical poets who wrote of the plant.  In Ulysses, Bloom’s father died from a (deliberate?) overdose of aconite which he was self-administering as a homeopathic remedy for neuralsia/depression.  Presumably the character failed to heed the counsel of Keats, who prominently alluded to aconite in the first stanza of his Ode on Melacholy which, in the second stanza, counsels the reader how to avoid despair through appreciation of the natural world, study of classical values, and delight in love.  On the other hand, the third and last stanza of the poem seems to indicate that sadness is a requisite part of mortality which allows us to savor beauty, love, and joy—indeed by counter-example melancholy guides us towards these transcendent (but transient) feelings.  Keat’s complex message steps far beyond thoughts of flowers and the underworld so I will leave you to read the entire poem on your own.  Here, however is the first stanza, entreating you away from aconite (and from other forms of self harm).  It goes without saying, gentle reader, that I am entirely of a mind with Keats:

NO, no! go not to Lethe, neither twist

Wolf’s-bane, tight-rooted, for its poisonous wine;

Nor suffer thy pale forehead to be kist

By nightshade, ruby grape of Proserpine;

Make not your rosary of yew-berries,

Nor let the beetle, nor the death-moth be

Your mournful Psyche, nor the downy owl

A partner in your sorrow’s mysteries;

For shade to shade will come too drowsily,

And drown the wakeful anguish of the soul.

Copidomopsis floridanum injecting its eggs into a caterpillar.

Sometimes horror is a matter of perspective.  For example, parasitoid wasps–some of the most horrifying hymenoptera–are also some of the most beneficial to humankind. The parasitoid wasps are a hugely diverse superfamily among the hymenoptera consisting of more than 6000 different species.  These insects are ancient, successful, and profoundly useful for controlling invasive species or pests (particularly various arthropods), however as soon as one knows what “parasitoid” means it becomes difficult to regard these wasps without revulsion and distaste. A parasitoid is a creature which lives inside another creature (the host) and ultimately kills/destroys that host by consuming it or by bursting out of it.  The detailed dynamics of this relationship are often grisly in the extreme, but they highlight the bizarre (not to say disturbing) mutualism which is such a feature of the natural world.

The emerald cockroach wasp or jewel wasp (Ampulex compressa)

Parasitoid wasps are especially alarming because of the extent to which they can manipulate the behavior of their host.  For example the emerald cockroach wasp (Ampulex compressa) is a solitary hunting wasp which finds a single cockroach and delivers a mildly paralytic sting to the roach’s thorax.  This first sting temporarily incapacitates the roach and allows the wasp to carefully make a second more meaningful sting to a precise spot in the roach’s brain which control’s the roach’s escape response. Not only does the wasp know where to sting, she utilizes a toxin which specifically blocks receptors for the neurotransmitter octopamine. The wasp then chews off a portion of the roach’s antennae and returns to her layer leading the captive roach by holding its damaged antenna like a leash. Inside the wasp’s burrow she plants a single egg on the roach’s belly and then seals the zombified insect inside the chamber with sand and pebbles.  After three days the wasp’s egg hatches and the new larva feeds for 4–5 days on the external portions of the roach.  It then burrow inside the still living roach and devours the creature’s organs in a progression which leaves the roach alive for a maximum length of time.  When the roach is near death the wasp larva builds a cocoon inside it, metamorphoses into an adult, and then bursts out of the roach carcass and flies off.

Aaaagh!

Across the many different parasitoid wasps there are many variations of this behavior involving different arthropod hosts–and specifically targeting the host’s eggs, lava, or adult form.  Additionally there are sundry vectors by which the parasitoid wasps control their hosts.  Not all wasps utilize targeted neuropoisons like the emerald cockroach wasp.  Wikipedia elaborates on how close the biochemical relationship between the parasitoid wasps and their hosts can become:

Endoparasitoid species often display elaborate physiological adaptations to enhance larval survival within the host, such as the co-option of endosymbiotic viruses for compromising host immune defenses. These polydnaviruses are often used by the wasps instead of a venom cocktail. The DNA of the wasp actually contains portions that are the templates for the components of the viral particles and they are assembled in an organ in the female’s abdomen known as the calyx.

In other words some wasps utilize ancient hunks of rogue DNA to directly or indirectly control (and then destroy) their host organisms.

Braconid wasp lavae (Cotesia congregatus) destroying a tomato hornworm

The biochemical sophistication of the parasitoid wasps does not end there.  Certain wasps seem to have a symbiotic relationship with plants.  When these plants are gnawed by harmful insects (especially beetles or caterpillars) the plants release specific chemicals which summon the parasitoid wasps, which, in turn, destroy the insects. An example of this can be found in that most ubiquitous of American staple crops, corn.  When beet armyworm caterpillars  (Spodoptera exigua) start eating a live corn plant, it releases a chemical which attracts  parasitiod wasps of the species Cotesia marginiventris (the larvae of which utilize beet armyworm caterpillars as hosts). If however the corn is invaded by corn earworns (Helicoverpa zea) it will release a different chemical which attracts a different   wasp Microplitis croceipes.  As scientists look further into such relationships, they are discovering that most plants have a vast range of chemical tags which are appealing to specialized parasitoid wasps (and to sawflies).  Perhaps one of the reasons that various blights have been able to make such deep incursions in new ecosystems is the absence of plants’ terrifying little friends.

Cotesia marginiventris on a corn leaf

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