I saw a similar thread regarding rocks/geology and I love biology (... most of the time), so I thought I'd make this! Ask me stuff about biology and I'll do my best to answer. Other people can jump in too if they want! ... I have no idea if this is something anyone would be interested in or not, but hey! If I can help answer even one question in a satisfactory way, I'll be happy.
*sets up camp in thread* i live here now. I would adore you forever if you continued the brain chatter from the mayo thread, or just talked about anything really.
Prions! They're pretty weird, pretty scary, and we don't really understand a whole lot about how they work at the moment. There's even some debate about whether or not prions are the root cause of the diseases they're associated with. So this info may be proved inaccurate! If I'm remembering right, prion is a contraction of "proteinaceous infectious particle". They're proteins, but they're folded in an incorrect way (and a protein's 3D shape, the way it's "folded", determines its function). They can make other proteins of the same type misfold, which disrupts normal functioning and leads to the symptoms of prion-caused diseases, which include memory issues, seizures, ataxias, sleep disturbances, and many others. In mammals, the PrP protein (prion-protein or protease-resistant protein) is highly conserved (very similar in sequence and structure) and expressed in many tissues, but predominately in the brain. In its normal form, it attaches to a cell's membrane and may be involved in cell signaling, but researchers aren't sure what its function is. When they're misfolded, the proteins clump together on the outsides of cells, forming a "plaque" that prevents normal cell functioning. Under a microscope, neural tissue with these protein clumps looks "holey" or "spongy" and prion-caused diseases are called "transmissible spongiform encephalopathies" (TSEs) because of how the tissues look. Although the gene (and resulting protein) is highly conserved in mammals, small differences (presumably in amino acid sequence and/or final folded structure) generally do not permit transmission between two different species. One exception to this is "mad cow disease" (Creutzfeldt–Jakob disease or CJD), which can be transmitted from cows to humans (and maybe the other way as well, but that probably doesn't happen nearly as often). Another is the people from Kentucky who ate squirrel brains and contracted TSE. So I was partially right in the other thread. One of the scariest things about prions is their incubation time (the time between infection and symptoms showing up), which can be extremely lengthy: 5 to 20 years. A person could have eaten infected beef in 1997 and only just now started showing symptoms of the disease. When there are only a few misfolded proteins about, they can't affect many of the correctly-folded proteins, but as misfolded proteins accumulate, they can affect more and more of the proper proteins. It's like a chain reaction, one that takes a very long time to "speed up" enough to cause symptoms. While some prions have the same amino acid sequence as the normal protein and just are misfolded, others can come about through mutations that cause amino acid substitutions in the protein's primary structure (its amino acid sequence), which then seem to promote the misfolding, likely due to amino acid interactions. This is how familial and sporadic TSEs occur: a mutation in the gene that makes the PrP protein. An example of this in humans is fatal familial insomnia, where people become increasingly unable to sleep. "Sporadic" TSE (sTSE) can occur in people without a family history of TSE and is the result of a very, very unfortunate spontaneous mutation. Luckily, mutations like these seem to be pretty rare occurrences! Something cool, though: animals that don't express the normal version of the PrP protein are protected from prions because the prions can't make the non-normal, non-prion version of the protein misfold. (Of course, having non-normal, non-prion PrP proteins could cause other health issues....) Researchers have done experiments in "knockout" mice that have no PrP gene, and therefor no PrP proteins, and found that they're resistant to prion infection. Prions have been found in fungi and plants as well. There are quite a few yeast proteins with that have prion versions. At least in fungi, prions don't seem to affect the health of the organism, but who knows? Maybe they reduce fitness in some way that hasn't been observed yet. They've been useful for studying the basics of prions and how they function to encourage misfolding of their normal protein counterpart. The thing I find really interesting is that, with one exception, in mammals, it's just one protein that has prion versions that cause diseases. Mammals make a lot of proteins. Humans make about 30,000 different proteins (this is probably a conservative estimate), for example, and there are two that have been found to be a) prone to misfolding and b) associated with disease. It makes me wonder, why that protein? Presumably there are other cell-surface proteins in neural tissue that are involved in cell signaling; why not one of those? Is it something about the folded shape that's unstable and prone to changing? How do the amino acids interact to make the different forms? Are there other factors that haven't yet been identified that prompt the change from normal to misfolded? It's a really interesting area that seems like it could spawn tons of research questions. My hypochondriac brain is freaking out a bit at the idea of prion diseases now, though, so I don't think I could be involved in that work, even if I were working with a mouse model or something and was very sure that I couldn't get TSE. Now I want an updated edition of The Family That Couldn't Sleep, with more recent discoveries covered! It's a super interesting book and before I read it, I only had the vaguest idea of what a prion even was. It's accessible and not too technical, so if anyone likes medical nonfiction I'd suggest it! Maybe not right before bed, though, prions are kind of... unsettling. I've heard them described as "zombie proteins" before, and it's strangely accurate.
Favorite spider has to be from the genus Thomisus, which are a type of crab spider that generally live in flowers and ambush insects that come to feed on the flowers. I loved watching the local species in central New York State in my MIL's garden, where they lived in daisies and irises and some of her other flowers. Sadly, I never got to see one catch anything, but I just love how they sit with their front legs out, waiting for prey. The ones I saw were mostly white or greenish, but a really neat thing about some Thomisus spiders is that they can change color if they move to a flower that they don't match! They're a bit limited in their color options: they can generally be shades of white, yellow, and red. However, with these colors they can match a lot of different flowers, and I think it's just incredible that they can do that. Go from being a yellow spider on a daffodil to a reddish spider on a tulip. And I just love how they look in general, whatever color they are. Spoiler: Spider close up Look at that cool dude, hiding on the underside of a daisy. Holding on with four legs while the other four are ready to grab something. And their abdomens look like crab shells, which I think must be part of why they're called "crab spiders". I'm also fond of the big dark spiders that are too stupid to not go into my parents' tub and then get stuck there. I have caught so many of them and transferred them someplace more hospitable because they love to get in that tub. (I don't know if they just fall in or if they deliberately go in there, but that tub probably has the highest concentration of spiders anywhere in my parents' house at any given time.) Not sure what species they are, but they're pretty big and very fast and they don't like being caught in a glass, even if it's for their own good. Arthropods are great, people need to give them more of a chance.
Jumping spiders are great! I love them too. Their family name is "Salticidae", which I think comes from the Latin word for jumping/dancing? (Taxonomists have the most fun, I want to name a new bacterial species so I can name it something that makes people smile.) Their eyes are so cool and unique?? I had no idea they had such good vision until I went looking for a bit more information. And the courtship displays are incredible! There's a prof working at my university who studies spiders in plant litter and this makes me want to ask him about if he's ever worked with jumping spiders. Now I'm sad that it's the middle of winter and I can't go out and search for spiders to watch. I get teared up sometimes just thinking of the incredibly variety of life, and spiders are really a pretty good example of that? We have web-builders, hunters, ambushers... and that's not even counting the differences in how webs are used! Trapdoor spiders are awesome, I've wanted to see them in action for a while, but I don't know if they're around here. I did get to see antlions though! Those sand-traps really work too. Sometimes I wish modern biology research involved more observation and fieldwork... I guess I kinda went into the wrong field of biology for that, most of my work is trying to make finicky programs run on my computer to analyze DNA samples. Another favorite arthropod: isopods. Spoiler: some pillbugs up close http://shop.bugsincyberspace.com/images/om_CanyonGiant1.jpg This isn't the same species, but I did some very preliminary genomic research on a pillbug species for my undergraduate research. It was the first time anyone had really looked at that species's genome, so it was really exciting. I wish I could have gone further with it, but not many people are researching pillbugs and the university I was at didn't offer a graduate program in biology. So now I look at bacteria (well, their genetic info).
Eyooooo~ Tagging in to get notifications - don't get much chance to nerd about biology since my uni graduation, so I may pop in here and there. *-*
