In theme with some of the other fun topical threads around here- I thought it might be fun to carve out a little corner for Biology related chatter and fun facts. :3
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Jessie and I were chattering earlier tonight about odds and ends, and a fun little thread of conversation that came from it were mythological diseases- that is, diseases in real life, that mimic the appearance of those found in stories. Cyclopia and sirenomelia, namely. Both are birth defects.
Cyclopia is particularly interesting to me because of how it pops up all over the place in terms of tangential association: weaving together genetics, botany, remedies taken during pregnancy, and cancer.
Picture this. Itās the 1950s, and youāre a farmer in Idaho who happens to tend to a flock of sheep. You let the little fluffy rascals scamper around and graze freely, and they seem to have a delightful time chomping down the fresh greenery. The sky is blue, the grass is green, and lambing is soon. Couldnāt be more beautiful weather for it. Thank goodness, too- the rains have been strange, this year. The thing is: when you inspect the new babies, you find one doomed to die in about a dayās breadth: a huge, angry eye eating away at the centre of its face, with a floppy scraggle of flesh in lieu of a nose, like some cubist nightmare.
That happened repeatedly to farmers, then- an epidemic of cyclops. As alarming as their appearance was- people wanted to get to the bottom of whatever affliction was sweeping through their flocks: farms run on surprisingly thin margins, and if this was contagious, better for them to squash it before it spread like wildfire.
It turns out that grazing was the culprit- with the moody rains changing typical grazing patterns in the sheep. Namely, they were chomping down on a plant by the scientific name of Veratrum californicum, or more commonly, the corn lily- and damningly, false hellebore.
A little bit of context. Hellebore is commonly taken as a folk medicine, wiveās tale sort of treatment: itās meant to treat early pregnancy discomforts, like morning sickness, cramping, and bad circulation. False hellebore is highly teratogenic: that is, it disrupts typical physiological development. Specifically, an alkaloid toxin called cyclopamine is responsible.
Plant alkaloids are secondary plant metabolites- which are a broad, diverse group of phytochemicals that can have both great therapeutic potential in humans, and also constitute toxic components in poisonous plants, like deadly nightshade. You might recognize some famous plant alkaloids: morphine, cocaine, quinine, ephedrine: many of them are drugs weāve since synthesized and produce en masse to treat all sorts of illnesses. Pyridine and quinolizidine alkaloids in particular are known to be associated with developmental defects. Cyclopamine is a steroidal alkaloid, (having the basic skeletal structure we associate with steroids, and various nitrogenous functional groups appended on. They closely resemble sterols, in particular.)
When a pregnant ewe ate corn lily in that sunny field, she would have ingested a great deal of cyclopamine: inducing cyclopia in her offspring. This is because it interrupts the sonic hedgehog signalling (SHH) pathway, which is crucial in early embryonic development. (Yes, it was named after Sonic the hedgehog: it controls the development of organs, and organization of the central nervous system and many body parts, as it helps organize things through gradient concentrations that help dictate cell fate. Abnormalities in its functionality in adults is associated with many, many cancers. More on this later.)
The SHH gene regulator helps distinct the eye field into two: without it, you donāt end up with two eyes, you end up with one. Symmetry in the body is crucial, as we see with the brain malformations in cyclopia: rather than having two hemispheres, the brain is one mass: resulting in one optic and one olfactory lobe (which causes the singular eye and odd ānoseā in cyclopia: sometimes this is absent, but usually itās a little squiggly tube of flesh.)
Weāve been talking about sheep, mostly- since they were the ones that the US government took interest in trying to figure out what on earth was happening. However, cyclopia impacts a number of creatures: weāve had documented cases in sheep, sure, but also in cows, kittens, sharks, pigsā¦
And humans, of course. (We are but animals, after all.)
(Let this be a grim reminder that you should never eat anything you arenāt 100% sure of its identification, be it fungi or otherwise. Natural does not mean safe.)
So, cyclopamine inhibits the SHH signalling pathway, and dysfunctions of the SHH pathway are also implicated in cancers, right? Well, a particularly nasty type of cancer is medulloblastoma- the most common type of cancerous brain tumour presenting in children, originating in the cerebellum. Medulloblastomas are all classified as grade 4 tumours: they are both malignant, and fast growing. They spread rapidly through the central nervous system through cerebrospinal fluid, but can also spread outside of it, such as to the lymphatic system, or bones.
A common form of medulloblastoma involves the overexpression of SHH. By having cyclopamine antagonizing the Smoothened gene (SMO gene), (a gene in the SHH pathway that regulates cellular growth, migration, invasion, and stem cell behaviours), itās possible to prevent cancerous cell growth, reducing their spread, and trigger typical cellular death (as cancer is a dysfunction of cellular apoptosis: cells donāt die when they ought to, forming aggressively growing masses, that damage and outcompete surrounding healthy tissues).
The brilliant thing is, while many cancers have developed a resistance to chemotherapy drugs- chemoresistant strains of cancer can be effectively treated with cyclopamine, such as when taken with paclitaxel (an isolate from the Pacific yew tree that had fungi growing into it that synthesized said isolate, which inhibits mitosis by disrupting the structure of microtubules, crucial to splitting chromosomes apart during cellular division) in the treatment of aggressive breast cancer.
So in a oddly serendipitous way: a whole bunch of dead baby lambs saved the lives of countless kids with brain cancer- and none of it would have happened without unusual rain patterns that just so happened to change the munchies that ewes were having. Like so many things in biological science: a multitude of factors converged just so, to produce the strangest butterfly effects.
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Cyclopia would be a great song name. Thatās all i can think about. Iām not good at biology, so this passed straight through me. 
I have a question: what exactly is a plant?
Iām not being flippant: Iām genuinely interested in the modern definition of the kingdom. This seems to have changed a lot over time. Both Wikipedia and Britannica are confusing when it comes to characterizing whole taxonomic kingdoms, and some other definitions seem to be circular (āthe kingdom Plantae includes all plantsā, yes, well done, champ).
It is not photosynthesis: most algae photosynthetize but some of them (red algae for instance) seem to be classified as Protista, not Plantae. All plants are eukaryotes, but that also includes Fungi, which definitely are not plants. Also, cyanobacteria photosynthetize and theyāre not even eukaryotes.
The confusion goes on: most articles say that there is a definition based on genome, but they donāt explain what that definition exactly is. Texts usually say things like āall plants have the following characteristicsā¦ā, for instance, one usually mentioned is that they show indeterminate growth (they grow body mass indefinitely until biological death), but - is the converse true? Are all organisms that exhibit indeterminate growth plants? No, fungi also grow indefinitely, so this does not characterize the kingdom either.
A textbook followed the heading āCharacterization of the kindgom Plantaeā by saying as the very first thing āThe kingdom Plantae includes the four following phyla: ā¦ā, then happily proceeded to enumerate angiosperms, bryophyta, etc, without ever defining why exactly only those divisions are included. All very confusing.
The closest to a rigorous definition I have found is āPlants are organisms that have an haplo-diploid life cycle and cell walls composed of celluloseā. This seems to say that both features need to be present. Is this correct? What then about the āgenome-based definitionā that I have seen mentioned? Are both definitions equivalent? Is this a matter of opinion? I need an aspirin.
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Iām anxiously waiting THE diseases vs. myth debate: porphyria vs. vampiresā¦
and, little question, I can post here about what I call āspeculative biology (a branch of speculative (science) fictionā ?
Best regards from Italy,
dott. Piergiorgio.
Hi Dr. Piergiorgio- Iād prefer if we tried to keep the thread on topic. Speculative biology is very fun, and something I also find interesting, but it might be best elsewhere, so that thereās no confusion between fictional and real life science! :3
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OK ! letās going on actual science; Iāll waiting your next installment !
Best regards from Italy,
dott. Piergiorgio.
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Probably one of the most frustrating things you encounter early on in Biology is the slipperiness of definition. There are many ways to detail what a species is, and each has their own application, though each seemingly talk circles about what theyāre exactly describing. Often, its more practical to define the particular definition you are working under, with the mutual understanding there are more ways to slice the proverbial cake.
Broadly speaking, today, most people prefer to use genomic relationships when organizing things. A lot of nomenclature when sorting things has historically been based on morphology, or the appearance of things: which we have found is not very accurate. There is a huge diversity of possible physical attributes- and a common case study are the C4 plants, which bizarrely, do not engage in photorespiration, as an evolutionary adaptation to their very arid environments.
Phylogeny is probably the definition I would use when trying to define what a plant is. Phylogeny concerns tracing ancestral relationships through genetic information, and determining the evolutionary history of species. Itās like making a family tree for people. A clade is a group of species that we believe to have a common ancestor. Plants can be thought of as forming a clade, that converges more recently within itself, than outside of the grouping. That is, any given member of the plant clade, is more related to other plants, than it is to members of other clades, such as an amanita mushroom, which belongs to the fungi clade.
This is a rather vague definition, but allows for the flexibility of species that exhibit unusual adaptations, but nonetheless, are still considered to be plants. As for what qualifies a āplant,ā outside of genomic relationships, typically in my classes, we defined it based on cellular composition.
Animal cells have flexible fat based membranes, which serve the purpose of defining a controllable environment, and modulating the rate of things entering and exiting the cell. Fungi and plants instead have rigid cell walls. (Fungi are bizarre organisms that straddle the existential boundary between animals and plants, and their reproductive cycles are a nightmare to study. Thatās not even getting into the conundrum that are viruses- the debate rages on whether they can be considered to be alive, and the mess that are protistsā¦) Fungal cell walls are mostly made of chitin, whereas plant cell walls are primarily made of cellulose, and hemicellulose.
There are other qualities that can generally be thought of as defining a plant, but in Biology, there are nearly always exceptions to the rule. I might hesitantly go to define a plant as a multicellular, eukaryotic (has a nucleus), generally non-motile, (canāt move, though movement is a broad term as well, as Mimosa pudica demonstrates) typically autotrophic* (produces its own food) organism that has hemicellulose or cellulose based cell walls.
*I say typically, because about 1% of angiosperms are considered to be parasitic plants. Nature is bizarre.
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I have a suspicion that Life cannot actually be nicely partitioned, even though we try for convenienceā sakeā¦
Yes, the exceptions and fringe cases are always fascinating to learn from. Take for example, the parasitoid wasps. While engaging in parasitic behaviour, that is, living off of another species- the shade of difference between a parasitoid and a parasite, is that a parasitoid organism is an obligate killer of its host. It is further distinct from similar creatures by killing their singular host over a duration of time, typically before the host can complete its own lifecycle.
One of the most fascinating creatures is the emerald cockroach wasp. A gorgeous, gleaming carapace like jewels: with all the savagery of a drunken brawler, and the precision of a surgeon. Its with an elegant brutality that they are able to attack and sting a cockroach just so, such that they are able to target specific ganglia: (nerve clusters that you can think of as akin to a rudimentary brain, of sorts.) Neurosurgery in the middle of a bar fight.
With incredible precision, they inject first into a thoracic ganglion, to temporarily paralyze the front legs: allowing it to slide into a particular area of the head ganglia that rules the escape reflex. This causes the cockroach to engage in aggressive self-grooming, before falling into a stupor. Then, it is nibbled on, and led by the antennae to be walled into a small tunnel, where laid eggs will hatch and use the host as a morbid cradle. Itās incredible, what they simply know how to do on pure instinct.
We are very lucky that they are generally quite shy, solitary wasps, who pose no harm towards humans. We have even used them as means of chemical-free pest control, like those that parasitize hornworm caterpillars, which cause damage to commercial tomato and tobacco plants. Those that are capable of painful stings, like the tarantula hawk wasp, are still very docile and would prefer to fly away from a human. Most stings involve actively trying to grab or trap the little lady.
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Thanks. This is something everybody is likely to agree with. Until the typical Zen master comes and says āNature just is. Itās the taxonomy that is bizarre.ā
What lovely creatures. Unlikely to ever be nominated for Miss Congeniality awards, I guess.
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but this high specialisation donāt run contrary to the basic darwinian criteria ? these parasitoids seems to me too dependant on a precise environmentā¦
Best regards from Italy,
dott. Piergiorgio.
There are many such microniches- survival of the fittest simply means that an organism is best suited to its particular environmental context, and evolution doesnāt care about perfect: simply good enough. The āpurposeā of life is to procreate, and pass down genetic information: so if it works, it works. Environmental pressures can produce bizarre results, and parasitoid wasps are a beautiful oddity in life.
There are animals that can quite literally only exist in extremely specific environments: like the Devils Hole pupfish, which are only found in Devils Hole, a water filled cave in Nevada. Despite repeated attempts to establish new colonies, every single one has failed to date. Sometimes organisms are just highly specialized to their environments, and their ecological interactions with other creatures around them.
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The USA allows for people to sell off their blood and blood plasma. This is not the case in the majority of countries, and notable due to the proximity, is definitely not the case in Canada. Kind of weird, right? Why is that?
The answer lies in a period of time referred to as the Contaminated Blood Crisis. This was a very contentious time, before the advent of advanced safety screening protocols and supportive technologies- and serves as grim reminder that not only does bigotry enact a price in blood: safety regulations are often writ in it.
A fundamental piece of context to the Contaminated Blood Crisis is understanding what hemophilia is, and its treatment. Essentially, hemophilia is a genetic disorder. It is a hemorrhagic disorder: that is, patients excessively, and uncontrollably, bleed. The specific subtype of hemophilia is defined by the particular gene defect involved: hemophilia B, which is the subtype I have, is a defect in the FIX (F9) gene. Hemophilia A, which is more common, is a defect in the F8 gene. The FIX gene is a coagulation factor gene, that is- it produces a protein required for blood to properly clot.
Because the gene is defective, hemophiliacs must have the coagulation factor replaced. Nowadays, this is done using very safe recombinant coagulation factor IX, which is infused like an IV, on a preventative, daily basis. It is considered to be a recombinant gene product, because we have isolated the particular human FIX genetic instructions, and shoved them into another organism, re-combining it, in order to synthesize pure FIX in vast quantities. That means you can make just what you need. This has not always been the case. (This therapy itself has many issues: patients often require port installation for the frequent infusions, patients can and do develop in a significant portion of the population antibodies that destroy the foreign FIX, and it is eye wateringly expensive.)
Prior to the advent of industrialized recombinant FIX production, if you bled a whole lot, the answer wasā¦ to give you blood. Well, that seems straightforward enough. (Later on, people realized you could instead give people just the plasma portion of blood, as thatās where the coagulation factors are concentrated, though it still is rather inefficient, and a tedious process.)
Well, where to get all of that blood? Donors, right? Wellā¦ How do you incentivize donors? America decided that it would do well to pay their donors. The problem? This largely drew in poor crowds, a significant portion of which were IV drug users- a group that had significant overlap with ex-prisoners, further compounded by the difficulties of finding stable income post-release due to carrying a criminal record. That particular slice of the population had a very high rate of hepatitis and HIV infectionsā¦ which are transmittable through exposure to blood.
What made this worse is America is big. America is heavily populated- and a significant portion of the blood made available on the market was American. (Interestingly, this is why, unlike Britain and Canada, Scotland was not nearly as impacted. Scotland had a smaller population, and so, was able to provide most of the blood it needed to supply its own needs.)
So, now, America is shipping out contaminated blood, internationally. Who is getting this blood? Well, there are your typical trauma cases, of course, unfortunate car accidents, and traumatic births, but also- hemophiliacs.
At this time, it was not uncommon for hemophiliacs to be sent to boarding schools that specialized in providing an education for the infirm, which involved having a dedicated nursing area on site that would handle the patientsā daily infusions of blood, or plasma. This meant that there was a significant increase in these patients acquiring hepatitis and HIV infections, which would progress into AIDs.
Young men developing HIV that progressed into AIDs. Who else fit this profile? Homosexual men.
This was at a time where homophobia ran rampant. When statistics first flooded the medical scene- because of who it impacted, and the stigma that HIV and AIDs carried, it was largely ignored. The disease, after all, impacted gay men- and, well, no one quite minded if they died, then. When it began impacting very young school children, though, people did start to grow a little more worried.
A very disconcerting fact is that, despite knowledge that the disease vector was likely imported American blood- and letters from medical doctors were sent up to the highest offices of government, it was largely concealed and brushed off. The reason being? Blood was expensive, and blood was difficult to keep in sufficient supply from purely domestic sources. If some people died, so be it. It was more financially advantageous to keep using the blood, and to silence whistleblower doctors. (This is why the British government was sued, and they still refuse to admit fault, though some compensation has been paid out to surviving hemophiliacs and their next of kin.)
It was a huge push behind researching how to make recombinant blood products: and also set the stage for very intense screening protocols to make sure that diseased blood does not enter the donation pool. Nowadays, it is basically unheard of for hemophiliacs to use whole blood or blood plasma as their coagulation factor replacement therapy, and instead, small vials of concentrated, pure coagulation factor IX are injected daily.
Other countries realized that incentivizing the marginalized masses to sell off their blood has disastrous results: you cannot rely on desperate populations to not take drastic measures. It ravaged public health. So, they banned the selling of blood, and now, Canada follows many other countries in only allowing donations that cannot be compensated monetarily- instead, they might give you a cool t-shirt, and a bite of something sweet to eat, with a bit of juice or water to wash it down.
But, well, America still allows you to sell your blood and blood plasmaā¦ So make of that what you will.
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This one I did get, and itās pretty crazy how much that āmoney outweighs livesā in so many peopleās minds, as long as they never have to interact in any way with said people.
It also is surprising how the majority of the population (probably, I wasnāt around then but I can guess?) could be so easily told āoh, AIDS is only because of gay menā, which sure it was, but then those who got it through other means would be blamed for being gay. But then children come into the mix, and ā¦ Then it probably changed. I wouldnāt at all be surprised if there were people who used that to blame the gay men even further, like āoh, see they really are dirtyā which would just be absolutely crazy to me that theyād just say that.
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On the subject of whichā¦
I found this recent news item interesting:
I thought the zombie-ant fungus (Ophiocordyceps unilateralis) was horrifying enough, but this left me wondering whether we and the rest of Animalia will need to bow to the fungi-cyborg overlords when their time comes. 
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Who will deal with this ?
(sorry, couldnāt resistā¦)
Best regards from Italy,
dott. Piergiorgio
As long as youāre not gay, of course. If you are, your blood is still considered unclean.
A local clinic used to send me monthly emails saying they had desperate need for blood donations, asking if I was still gay. Because if I wasnāt, they would really appreciate my blood type!
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Yeah, this hits too close to home. My father figure used to donate blood frequently- because he appreciated that donors gave, and thought that in an abstract sense, he would want someone to donate for his little girl (especially with the whole having hemophilia thing,) so it was only fair for him to do the same thing for someone elseās kid in need: but then started dating men, so heās now ineligibleā¦ after like, ten years of donating.
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Interestingly, I overheard the same question earlier this week, between a couple of science teachers in my department. The specific case was an organism with cell walls, but does not photosynthesize. The conclusion was that it was a plant (not a fungus) because the cell wall material was chemically similar to the cell wall material of other plants, supporting the theory that it is more evolutionarily related to other plants than to the organisms we call fungi.
Generalizing that, the classification of organisms (at all taxonomic levels) is related to current theories in about evolutionary relationships, based on evidence from genetics, biochemistry, morphology, and the fossil record. Can theories about relatedness change? sure they do. Thatās science.
Without evolutionary theory, taxonomic classification is kind of arbitrary, as there would be no other reason to suggest the ordering of organisms alive today and their distance ancestors along a branching tree-shaped manifold.
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