Bite of Spine

Vertebrates think they’re pretty hot stuff. I mean, humans think  they’re pretty hot stuff in the first place, but in a broader sense we always give anything with a spine more attention. Considering that excludes over 1,057,000 species, we’re being just a little snooty. Porifera, the phylum composed exclusively of SPONGES, alone has more than twice Chordata’s species count. Chordata is so desperate for members, not all of them are even strict vertebrates. To be a chordate, an organism must only meet four requirements at some point. Like if you could get a lifetime membership at the country club simply because you lived in your rich uncle’s house near there at some point.

So what are these requirements? First, chordates must possess a dorsal hollow nerve cord. This is a nerve that runs along the back and can eventually develop into the brain and spinal cord. Beneath the DHNC and above the gut sits the notochord, a bendable rod that acts as structural support in preparation for or instead of a vertebral column. Now, believe it or not, all chordates must have had a muscular tail at some point. Sit down to hard on a hard floor and you’ll find your tailbone (I don’t actually recommend that, it hurts like hell), it didn’t develop fully but it is still there as a small vestigial structure of fused bones. Finally, chordates must have gill slits. Located in the throat, these obviously were originally intended for aquatic life, but unless you’re a sea squirt or a lancelet fish, these will close up eventually.

Although it’d be badass to have gills…

 

 

Source

-. 2010. GRE Subject Test: Biology 5th Ed. Kaplan, New York.

A Bite of Fat

Because comicon is this weekend and comicon/my costume is SERIOUS BUSINESS, my updates will be bite-sized for the next few days. Furthermore, Friday and Saturday posts may not happen. We’ll see. Anyway, for the first bite, I have a tidbit that couldn’t fit in yesterday on BATs. Not bats, brown adipose tissue, or brown fat.

Brown fat is MAGICAL you guys. It’s filled with mitochondria, a cell organelle used for generating ATP (cellular energy source) from larger molecules like triglycerides. What does that mean? It means rather than store all the fats that pass through, the mitochondria burn off excess energy as heat. Small and young mammals have big stores of brown fat to keep warm make up for their high surface to volume ratio (tiny body, but lots of surface to lose heat from).  Some adult mammals will retain a lot of brown fat. This decreases their ability to store energy, but this could be a trade-off in order to remain lean and highly mobile. Remember the Hungry Tiger? You bet he has brown fat. You also better bet that scientists are working on a way to renew brown fat stores in adult humans with weight issues. It’d be a hot alternative to lap-bands and the like. Get it?? Hot and it’s a thermoregulator and- OK yeah, I’ll go.

Told you I had stalkers.

 

 

Source

Sherwood, Lauralee, Hillar Klandorf and Paul Yancey. 2005. Animal Physiology: From Genes to Organisms. Thomson Brookes/Cole, Belmont, CA.

Hungry Hungry Tigers

So we all know the media focuses way too much on “fat=bad”, but not everyone is aware of why this is wrong besides putting forth unnecessary pressure for the world to shuck any and all fat they may possess. At this point, if you’ve read my last post, you know why we need fat. But I know what you’re thinking, “Ophid, too much fat is bad for you! Also your room is a mess.” Right on both counts, sort of. That “too much” is hella vague and I can find everything in my room that I need to find, thank you very much. Anyway, “too much” fat is highly dependent on an individual’s body chemistry. So you can have two people of greatly differing sizes, that will never share a jean size in their lives, but they’ll share excellent health and blood work worthy of a gilded frame over the mantle. Of course, the key is that they both maintain healthy lifestyles, doesn’t matter what your metabolism, if you live on Red Vines and French fries you better just sit back and watch your blood pressure rocket to the moon. Lot of models out there have skinny, tiny bodies and skinny, tiny blood vessels from all the cholesterol they’ve accumulated. So they may be walking the runway, but really, it’s what’s on the inside that counts.

Back to the body chemistry. Another vague phrase, but it won’t stay that way, I promise. First, understand that cells in adipose tissue releases a chemical called leptin. Leptin signals satiety, and the more fat cells present, the more leptin is released. As a result, overall appetite decreases. Conversely, the less stored fat, the greater the appetite. Which explains why I never stop eating. I’m like a hobbit, except hobbits don’t turn feral when hungry. So there’s that.

Feral rage brings me to my next point; adipose set points. Although the general rule is more fat leads to more leptin secretion, bodily reaction to leptin levels in the blood vary greatly. Example: anyone here read the Oz books? There’s a character called the Hungry Tiger who, I kid you not, is always talking about wanting to eat fat babies. The Hungry Tiger wants to eat all the time but does not eat as much as he wants because he’s afraid he’ll eat a baby, or something. I have a deep kinship with the Hungry Tiger. Except for the baby thing. Anyway! If the Hungry Tiger actually got to pig out on some baby-free food and gained wait, the rise in leptin would make his appetite drop dramatically. He would be The Tiger Formerly Known as the Hungry Tiger. Actual tigers are like this; they’re adapted to a food-plentiful environment and though they do sit around a lot, when they do gain some weight, their appetite disappears. As a result, they remain lean and agile. Conversely, a high adipose set point means that it takes a lot of stored fat and high leptin secretion before appetite decreases. This set point is perfectly adapted for “feast or famine” habitats; animals will bulk up until their body hits a good stopping point and then they’re good to go. These set points keep individuals at very stable weight ranges. So if you’re someone watches their diet like a hawk (whatever your size), you’re eating right, eating enough, but budge nary a pound off the norm, it’s because your body is adapted to a very specific lifestyle and won’t budge for love or money.

Besides an unhealthy diet, problems arise if you eat beyond satiety, or have a genetic mutation. Specifically in the ob gene, the ob gene controls leptin release, if that mutates it becomes functionally absent (it doesn’t work) so leptin is not produced. As a result, chemical satiety signals disappear almost completely. This is a heritable trait and means you have a very variable weight but tend towards heaviness to the point of obesity.

Hope this gives y’all a better understanding of energy, body fat and body type adaptations. If you’ll excuse me, I’m going to go clean my room…

He’s totally gonna eat that kid.

 

Source

Sherwood, Lauralee, Hillar Klandorf and Paul Yancey. 2005. Animal Physiology: From Genes to Organisms. Thomson Brookes/Cole, Belmont, CA.

Fat is Phat

Riddle me this! What provides the healthiest and most efficient energy storage, thermal insulation and protective layers for your vital organs? Sorry, “shirt made of Red Bull” is incorrect. Red Bull isn’t healthy and also that is not a thing. The answer I was looking for was “fat”.

Your body has three forms of metabolic fuel at its disposal: carbohydrates, proteins and fats. These are stored as glycogen, body protein and triglycerides, respectively. Glycogen is stored in the muscle and liver. It may be broken down into glucose for energy, which is essential for brain function, but glucose provides only a little “quick energy” that easily runs out between meals. This can’t be solved by pouring a lot of glucose in the blood, too much will dehydrate cells. So how about protein? The amino acids composing proteins may be pulled for energetic requirements, they’re necessary to the brain during a fast and there’s more stored than you’ll ever use up…cause you’ll cripple yourself and die before you do. Not-so Fun Fact: during times of emotional stress (like finals and senior thesis writing), the body will skip straight to cannibalizing the muscle. This is very unhealthy in the long run, but your your body likely is trying to anticipate physical stresses like famine, so we’ll give it a break. Cause fat is where it’s at. For the same amount of energy, fats in adipose tissue (tissue of fat-containing cells) require less space and mass than glycogen. It may not break down into fatty acids quickly, but it’s ready when the blood glucose it gone and won’t run out easily; the human body usually keeps about 2 months worth of energy in fat.

More on fat later. Time now for me to build a gee-tar.

 

Source

Sherwood, Lauralee, Hillar Klandorf and Paul Yancey. 2005. Animal Physiology: From Genes to Organisms. Thomson Brookes/Cole, Belmont, CA.

In Which I Argue with Hawaii

Sea pigs that squiggle and hagfish with no eyes, those naked mole rats and larvae from botflies, cranky rock crabs that crush my nerve endings, these are a few of my LEAST favorite things. Not the dog bites, not the bee stings, those bitches. OK, I hate those things mostly cause they intolerably ugly or intolerably UUUGH (botflies I’m looking right at you and don’t even pretend I’m not), call me petty, whatever. These things don’t scare me, though. They’re not dangerous, why would they? Venomous snakes and spiders are kind of scary, but venom is a hassle for them to produce so they try to warn you when you’re too close and making them nervous (see: rattlesnakes, spitting cobras, etc). Hell, brown recluse spiders and black widows will run before anything else. Large predators, sure, but pack some bear spray, travel in groups and I should be good to go. Sharks? Pssht, I barely sea kayak and have no interest in surfing so no shark is going to mistake me for a turtle snack anytime soon. You want to know what’s really scary? What would make me don a custom head-to-toe wetsuit if I went swimming in Australia? Box jellyfish. Goddamn box jellies. I can hear you Hawaiians out there (assuming I have Hawaiian readers…), “Man, what’s the deal? You get stung by a jelly, you get over it. Spray some ammonia on it and get back in the water.” I call bullshit, Hawaii. Box jellies are serious business. So what if it’s not a true jellyfish (scyphozoa) and belong to its own class (cubozoa). Even your Irukanji box jelly (Carukia barnesi) venom can cause difficulty in breathing, vomiting, coughing and also possibly death. Not to mention the excruciating pain, at the sting site, as well as the stomach, limbs, back and head. Put ammonia on THAT, Hawaii.

So why is a dumb jelly scarier than a snake that can spit venom at my eyes or a large cat that could rip my throat out with only a “playful’ swipe? You can prepare for that shit. Walk away from snakes you don’t know (and say “no”  if they offer you drugs) and if you think any big mammal is a danger, CARRY BEAR SPRAY. As a side note, I’ve been stalked by a tiger while working at a zoo. At least the tigers there thought that if they weren’t moving, you couldn’t see them. So I’d be walking to lunch past the back of the tiger exhibit and hear a sound, turn, and see a tiger frozen mid-step. Turn away, turn back, tiger had moved one more step. Maybe had tried hiding behind a rock the size of his head (but not the rest of his 350lb+ bulk). Not that Mushi would necessarily behave like that in the wild, BUT IT’S FUNNY. Also, bear spray does wonders. ANYWAY, that “dumb” jellyfish has eyes. Four small structures simply respond to light and accompany two real eyes; structures complete with lenses, corneas and retinas. It can see, process sights and hunt based on that. You may not look like dinner, but that “dumb” jelly does not care enough to avoid you. DOES NOT CARE. It can kill you just because it can’t be bothered to try and avoid you. This is a predator skilled enough to find its prey and deadly enough not to worry about predators of its own. It can also kill you when it’s dead. How about THAT, Hawaii?

ADDENDUM:Almost forgot to explain the box jellies mode of envenomation. Remember the nematocysts? Of course you do, I talked about them in Nudi Time ( https://dailyscienceblog.wordpress.com/2013/01/21/nudi-time/ ). Basically those are cells that hold contact-activated barbs on threads. It’s like a land mine, but instead of an explosion when you touch it, a poisoned grappling hook shoots out. Explosion of HORRENDOUS PAIN. Also the barbs regenerate after use. In most jellies the cells stop working after death, but box jellies are determinedly mean bastards so their nematocysts can still fire after they die. Happy swimming!

 

Source

Laidler, Keith. 2009. Animals: A Visual Guide to the Animal Kingdom. Quercus Publishing Plc, London.

On Ditching Close Friends

Since I creeped you all out with parasites yesterday, I’ll try and make it up today with anti-parasitic drugs. No, I am not giving free samples, but I AM explaining a little bit of how they work. Just as good, right? Right, don’t argue.

Ectoparasites like fleas and ticks can be repelled and eradicated fairly simply. They’re so small, you can easily make their environment too toxic for them to survive (either via topical or oral medication). Hell, to a certain degree, a garlic and onion heavy diet will repel blood-sucking parasites. Doesn’t take a lot, those sucky suckers are finicky suckers, sucker. Helminths, however, require drugs as sophisticated as those used in viral or bacterial infections. Considering that certain worms like tapeworm can be many feet long, creating a toxic enough environment for a helminth could be too toxic for you too. So antihelminthics will paralyze or increase permeability of the worm’s plasma membrane. Of course, there are drugs that will destroy on contact, but these are to be used with caution. This is strong shit.

Want more? Talk to me later. Got a busy week so we’ll see how much I update. Should be back to normal by Friday, though.

 

Source

–. 2008. “Antihelminthic Drugs”. Gale Encyclopedia of Medicine. The Gale Group, Inc.

The Closest Friends You’ll Never Want

This poster is no joke. Once upon a time, quack doctors and snake oil salesmen peddled tapeworms to the unwary to cure them of “life-threatening fat”. Although the chances are that the quacks probably had as little idea as any of how life-threatening their diet aid was. Stories of fasting and holding an orange slice between your teeth or smoking circulated as means to cure oneself of the parasite. I know, right? You’d have better luck fishing for the thing.
As pleasant an opening as that is, it’s the nicest way I could introduce a topic like parasites. They’re not pleasant, but honestly, they are VASTLY under-studied. Look at a list of parasites with drugs associated with their eradication and you’ll notice most occur in well-developed countries. Granted, it makes sense; roundworm in pets living so close to the family can be easily transmitted to kiddos, and though malaria isn’t big in the US, it’s transmitted via the mosquito, whose sheer pervasiveness keeps it on the world’s (particularly tourists’) radar. Many other parasite-based diseases are associated with contaminated water (a monumental issue to tackle on its own), which tourists and other foreigners know to avoid, but locals either have no choice or don’t know that they can fix the problem. So prevention is the first concern here.
So what’s a parasite? A parasite is an organism that lives on or in a host, to the parasite’s benefit and the host’s detriment. Many parasites are transmitted via vectors (carriers) that will carry them from the environment or an intermediate host (where sexual reproduction does not occur) to a primary host (where sexual reproduction will occur). Mosquitoes act as a vector for a variety of parasites, such as those causing malaria and elephantiasis. Speaking of those bastards, they are best known for carrying malaria, a disease cause by protozoa, single-celled parasites that can live free in the environment or in a host to royally mess shit up. Other well-known parasites include helminthes (roundworm, heartworm, sand worms, etc) and ectoparasites (ticks, fleas and xenomorph face-huggers).
Now that you’ve had the intro, I can get into the good stuff…tomorrow. Definitely tomorrow. It’s my bedtime now.

 

Source
— 2010. “Parasites”. Centers for Disease Control. Atlanta. 19 Feb, 2013

Love is in the Air

Bow chika wow wow, guys! It’s Valentine’s Day! For those of you not snuggling up to sweeties, I have an especially romantic post tonight about courtship and reproductive habits. Better than the Notebook, even. Anyway the three main social systems of animal reproduction are monogamy, polygamy and fission-fusion. Sounds simple, but how different animals actually work within each system is pretty cool.

Monogamy is pretty straightforward; in a given monogamous species, either sex may put on a display to attract a mate. Interestingly enough, the sexes in monogamous species tend to have a more similar appearance than in non-monogamous species. Blue-footed boobies and buff-breasted sandpipers (dare you to say those birds’ names ten times, fast, without tittering. Heee, tittering…) follow a LEK system of courtship in which the males display in “arenas” where females will choose the best display. Humpback whales, too, have a LEK sysem where the males serenade the ladies. However, in Clark’s grebes, both sexes will put on dancing displays and pairs are decided by how matched their grooves are. Regardless of the species, once bonded, they’re mostly stuck with each other, either for the season or for life. I say “mostly” because certain lady songbirds will cheat on their stable fella for some hot hunk with better genes, but if Mr. Stable finds out, she and the kids are out on their asses. It’s a risky business, so not all females of a species that may display cheating behaviors will do so.

When folks think of polygamy, they think of one male with many females. As is seen in deer, seals, certain Mormons and lizards. This is polygyny, in which males will compete (usually in combat) for control over a “harem” of females. In polygynous species, the male is often a lot larger (in seals, males can be twice as large as the females). The females don’t have much choice in the matter, unless they want to cheat with a sneaky, smaller males. Which they do. A LOT. Up to 30% of offspring in a grey seal harem will not belong to the alpha male. On the other hand, there is the lesser known polyandry, in which females will compete for a harem of males. This is not as common because the time burden of caring offspring to term often precludes taking multiple mates. Seahorses have got that handled, though. The female will mate with a male and leave the fertilized eggs with him, so he’ll carry the eggs to term in a pouch while she finds more males to be stay-at-home dads.

Finally there’s fission-fusion, which could be simplified to “promiscuity” but that doesn’t quite cover it. Fission-fusion involves fluid hierarchical social system, where groups form for more than just meeting reproductive needs like mate-finding or parenting, but hunting, defense or even just social bonding. Dolphins, orcas, humans and chimps all follow a fission-fusion system. If you know teenagers, you know how much they like their groups. Just watch the Facebooks or Gossip Girl or whatever it is kids watch.

Anyway, hope that dip into the animal dating pool was interesting enough to last y’all for a few days. I will be out of town and out of internet while I visit my granddad (who, I assure you, is awesome). So cheers until Monday!

 

 

Sources

Yancey, Paul. 2011. “Reproductive Adaptations.” Marine Biology. Whitman College. Walla Walla, WA. Lecture.

Pathogen Time Part 2

Continuing from where I left off yesterday…Once upon a time there was my brother. My brother lived in a large closet for a year in college because, well, COLLEGE. Also, broke. At some point he got sick (like ya do when you’re on a trimester system and taking exams every few weeks), then he got sicker and then a doctor took a chest X-ray. Apparently my brother’s lungs had taken to raising fungi for fun and profit. Except it wasn’t fun and the doctor cost money. This was also when we found out about the discovery of black mold in his house. Yaaaay…Anyway, the story ends happily because whatever had set up camp in my brother was not actually black mold and eventually went away. How did this happen in the first place? Well, if bacteria are zombies and viruses are spies, fungi are aliens. Pathogenic fungi are like aliens conducting a disorganized and under-planned invasion of your body; like Superman’s parents, they want to send their little babies/spores off in escape pods to grow somewhere safe (and damp and warm and probably rotting). Except instead of a farm or even a nice rotting log, their kids end up in fungi equivalent of a space beast. Unfortunately for the space beast (you), lungs and other soft, damp tissues can grow fungi pretty well. Tissues like your eyes, sinuses, bones, lining of the heart and brain. I know, right? BRAIN MOLD. Even a common mold like Cladosporidium can really ruin your shit. Our bodies can reject spores and other foreign particles with coughing and sneezing, but the immune system can do a pretty good job of kicking the confused aliens out. Failing that, anti-fungals are a beautiful, beautiful thing.

Prions, I don’t even know what kind of video game prions would work in. They. Are. Nasty. Shit. For a while, believing in prions was like being That Guy in the medical community. You know, the one whispering conspiracy theories in the break room about how anesthesia had tracking chips in it and scrubs were a symbol of The Man. Because prions are only proteins, similar to ones you already possess yet capable of knocking other cerebral proteins completely off kilter, it seemed ludicrous to suggest a “protein infection” would cause loss of motor skills, dementia, convulsions and death. No DNA as in viruses, nothing. Thankfully, researchers Tikvah Alper and John Stanley Griffith did not mind being Those Guys for a while until support mounted for their hypothesis on the infectious agents of scrapie (a sheep disease) and Creutzfeldt-Jakob disease (human mad cow disease). There is no cure, but mind you have to try a bit to catch a prion. They live in nervous tissue and transmit orally, but since the discovery of mad cow, the butchering and feeding of beef cattle has been carefully regulated to prevent further outbreak. Also, if you’re reading this, you’re probably not a sheep (or at least you’re a very talented sheep) so scrapie is out, and you’re most likely not a cannibal, so kuru is out too. Fun fact: in the post-apocalyptic movie Book of Eli, the main characters can indentify cannibals because they’ve got “the shakes”, meaning that they have kuru from eating too many people and not being picky about nervous tissue. Anyway, I thought that was a cool detail.

Oh, I didn’t include parasites? Well now, maybe I’ve got something planned. Y’all will just have to see.

 

 

Source

-. 2010. GRE Subject Test: Biology 5th Ed. Kaplan, New York.

-. 2012. “Other Pathogenic Fungi”. Centers for Disease Control and Prevention. 13 Feb 2013. <http://www.cdc.gov/fungal/other/&gt;

Pathogen Time or, BOOM Headshot

I was going to write about cell organelles, but I DO WHAT I WANT, so it’s really Pathogen Time. Plus, this nicely mirrors Video Game You (see: https://dailyscienceblog.wordpress.com/tag/john-mayer/ ), “know thy enemy” and all that. The big bosses are bacteria, viruses, fungi and prions.

Fighting a bacterial infection is basically the same as fighting zombies. They eat everything you love  (brains/nutrients), they’re dumb and gross and there are a shit ton of them. Thankfully, a headshot (with bullets, machete or antibodies) usually does the trick. Also, for common infections, you just need time to cut through the teeming horde. Less common ones require multiplayer mode/drugs. Although out-competing you for resources is the bacteria’s main mode of attack, they may also release toxins or invade your cells. Bacteria can also form “plaques”, consisting of bacteria and nutrients they are growing on/around. These can do a LOT of damage if left unchecked; the plaque on your teeth needs to be brushed off/scraped off with that God awful metal hook by the dentist or the bacteria will destroy your teeth. Do not let them destroy your teeth. A win for bacteria is a win for zombies.

Viruses on the other hand, while not technically living, are much more sophisticated than the single-cellular zombies on your teeth. The reason why they’re not technically living is because they cannot self-maintain, reproduce or metabolize on their own. For that, they use YOU. Yup, viruses are mad spies that hijack your cells into aiding their heinous schemes. Those schemes being replication of viral DNA and synthesis of viral capsids (think capsule) for the TOTAL TAKEOVER OF YOUR BODY. Remember that chickenpox you had? It planted its DNA in your cells, waiting until you’re old to hit you with shingles. Or not, viruses get senile too. Lucky for us, cytotoxic T-Cells are always up for playing a round of spy vs. spy.

Despite what you may think, fungi are not such fungis (GET IT GET IT). Just ask my brother about the crap that grew in his lungs when he lived in a glorified closet for a year. But I will tell you more about that tomorrow.

OH THE SUSPENSE. OH THE ALLCAPS.

 

 

Source

-. 2010. GRE Subject Test: Biology 5th Ed. Kaplan, New York.

Wassenaar, T. M. 2009. “Pathogenic Bacteria: Bacterial Pathogenicity”. Virtual Museum of Bacteria. 12 Feb, 2013. <http://bacteriamuseum.org/cms/Pathogenic-Bacteria/bacterial-pathogenicity.html&gt;