The Beginnings of Jurassic Park: Dinosaur Blood Discovered? (A Guest Post)

A reposting of an original article by Samantha Vold

The classic tale of Jurassic Park, where dinosaurs once again walked the earth has tickled the fancy of many a reader. Dinosaur DNA preserved in a fossilized mosquito was used to bring these giants back to life. But in real life, it was previously thought that there was no possible way for organic materials to be preserved, that they often degraded within 1 million years if not rapidly attacked by bacteria and other organisms specialized in decomposition. Skin and other soft tissues, such as blood vessels, would never withstand the test of time. Or would they…?


T. rex skeleton at Palais de la découverte. Image by David Monniaux at Wikimedia

In 1992, Mary Schweitzer was staring through a microscope at a thin slice of fossilized bone, but this bone had something unusual. There were small red disks located in this tissue and each had a small dark circle in the middle resembling a cell nucleus, the command center of the cell. And these little disks very much resembled the red blood cells of reptiles, birds, and other modern-day vertebrates (excluding mammals). But it wasn’t possible, was it? These cells came from a 67 million-year old T. rex. And it was commonly accepted that organic material never lasted that long.


Comparison of red blood cells. Image by John Alan Elson at Wikimedia

This opened a huge controversy in the scientific community, but Schweitzer persisted. She consulted with her mentor, Jack Horner, a leading scientist in the paleontology field, and he told her to prove to him that they weren’t red blood cells. Schweitzer took the challenge and began to run some tests.

The first clue to these mysterious scarlet-colored cells potentially being red blood cells was the fact that they were located within blood vessel channels of the dense bone that were not filled with mineral deposits. And these microscopic structures only appeared inside the vessel channels, as would be true of blood cells.

Schweitzer then began to focus on the chemical composition of these puzzling structures. Tests showed that these “little red round things” were rich in iron, and that the iron was specific to them. Iron is important in red blood cells as it helps to transport oxygen throughout the body. And the elemental make-up of these little red round things differed greatly from the surrounding bone and sediment around them.

The next test was looking for heme, a small iron-containing molecule that gives blood its characteristic color and allows hemoglobin proteins to transport oxygen throughout the body. Schweitzer tested for this through spectroscopy tests, which measure the light that a given material emits, absorbs, and scatters. Her results from these tests were consistent with what one would find in heme, suggesting that this molecule existed in the dinosaur bone she was analyzing.

Schweitzer then conducted a few immunology tests to see if she indeed had found hemoglobin in these ancient bones. Antibodies are produced when the body detects a foreign substance that could potentially be harmful. Extracts from the dinosaur bone were injected into mice to see if antibodies were produced to ward against this new organic compound. When these antibodies were then exposed to hemoglobin from turkeys and rats, they bound to the hemoglobin. This suggested that the extracts that caused an antibody response in the mice included hemoglobin. This in turn suggested the T. rex bone contained hemoglobin, or something very similar.

Through years of research, Schweitzer has shown that what was once believed to be impossible is indeed true. Soft tissues, blood cells, and proteins can withstand the test of time. This process is possibly done through iron binding to amino acids (the molecules that make up proteins) and thereby preserve them. Research is advancing in this area, but as of yet, no DNA has been found to bring Jurassic Park to life. But for the avid believer, don’t get up hope yet. Perhaps one day we truly could walk amongst dinosaurs.


References:

Fields, Helen. (May 2006). Dinosaur Shocker. Smithsonian. Smithsonian Magazine.

Pappas, Stephanie. (13 Nov. 2013). Mysteriously Intact T. Rex Tissue Finally Explained : DNews. DNews. Live Science.

Schweitzer, M. (2010). Blood from Stone Scientific American, 303 (6), 62-69 DOI: 10.1038/scientificamerican1210-62

Vampires!

Photo by Alejandro Lunadei at Wikimedia.

A reposting of an original article from October 19, 2015

Vampire mythologies have been around for thousands of years, terrifying the young and old alike with stories of predatory bloodsuckers that feed on our life essences. You may not believe in vampires, but they are all around us. In fact, you may have some in the room with you right now! You just don’t notice them because they are not human, or even human-like.

Vampires feed on the blood of their victims in order to sustain their own lives. This phenomenon, called hematophagy, is more common than typically occurs to us at first. Just take mosquitoes and ticks as examples. Once we’ve opened our minds to the idea of bloodthirsty arthropods, we quickly think of many more: bedbugs, sandflies, blackflies, tsetse flies, assassin bugs, lice, mites, and fleas. In fact, nearly 14,000 arthropod species are hematophages. We can expand our thoughts now to worms (like leeches), fish (such as lampreys and candirús), some mammals (vampire bats), and even some birds (vampire finches, oxpeckers, and hood mockingbirds). We’ve been surrounded by vampires our whole lives, we just never sat up to take notice!

Hematophagous animals are not as scary as mythical vampires, in part because they don’t suck their victims dry – they just take a small blood meal to sustain their tiny bodies. Hematophagy is not, in itself, lethal. However, the process of exposing and taking the blood of many individuals transmits many deadly diseases, like malaria, rabies, dengue fever, West Nile virus, bubonic plague, encephalitis, and typhus.

Because blood feeders do not kill their meals, feeding can be even more dangerous for them than for traditional predators. As a result, many hematophagous animals have developed a similar toolkit. Many have mouthparts that are specialized to work as a needle or a razor and biochemicals in their saliva that work as anticoagulants and pain killers. Their primary skill, however, is their stealth: they can sneak up on you, eat their meal, and be home for bed before you even notice the itch.

Although a few species, like assassin bugs and vampire bats, are obligatory hematophages (only eat blood), most hematophages eat other foods as well. Somehow, Dracula is not quite so intimidating when you imagine him drinking his morning fruit juice, like many mosquitoes do.

Why drink blood in the first place? Blood is a body tissue like any other, and it contains a lot of protein and a variety of sugars, fats and minerals, just like meat. However, blood is mostly water, which means that a blood meal contains less protein and calories than the same weight of meat. Because you need to consume so much more to get enough protein and calories out of a meal, large animals and animals that generate their own body heat can't usually rely on blood meals alone. So much for human-like vampires that only live off the blood of their victims.

A deadly vampire spreading malaria. Photo by the CDC available at Wikimedia.

So true vampires are everywhere, but they are small, take small blood meals, don't generally kill their hosts, and often use blood to supplement their other meals. Not so scary any more, are they? ...Although, about 3.2 billion people (about half the world's population) are at risk of contracting the deadly disease, malaria, from these bloodsuckers... so maybe you aren't scared enough. Bwaa-haha!

The Beginnings of Jurassic Park: Dinosaur Blood Discovered? (A Guest Post)

A reposting of an original post by Samantha Vold on February 9, 2015.

The classic tale of Jurassic Park, where dinosaurs once again walked the earth has tickled the fancy of many a reader. Dinosaur DNA preserved in a fossilized mosquito was used to bring these giants back to life. But in real life, it was previously thought that there was no possible way for organic materials to be preserved, that they often degraded within 1 million years if not rapidly attacked by bacteria and other organisms specialized in decomposition. Skin and other soft tissues, such as blood vessels, would never withstand the test of time. Or would they…?


T. rex skeleton at Palais de la découverte. Image by David Monniaux at Wikimedia

In 1992, Mary Schweitzer was staring through a microscope at a thin slice of fossilized bone, but this bone had something unusual. There were small red disks located in this tissue and each had a small dark circle in the middle resembling a cell nucleus, the command center of the cell. And these little disks very much resembled the red blood cells of reptiles, birds, and other modern-day vertebrates (excluding mammals). But it wasn’t possible, was it? These cells came from a 67 million-year old T. rex. And it was commonly accepted that organic material never lasted that long.


Comparison of red blood cells. Image by John Alan Elson at Wikimedia

This opened a huge controversy in the scientific community, but Schweitzer persisted. She consulted with her mentor, Jack Horner, a leading scientist in the paleontology field, and he told her to prove to him that they weren’t red blood cells. Schweitzer took the challenge and began to run some tests.

The first clue to these mysterious scarlet-colored cells potentially being red blood cells was the fact that they were located within blood vessel channels of the dense bone that were not filled with mineral deposits. And these microscopic structures only appeared inside the vessel channels, as would be true of blood cells.

Schweitzer then began to focus on the chemical composition of these puzzling structures. Tests showed that these “little red round things” were rich in iron, and that the iron was specific to them. Iron is important in red blood cells as it helps to transport oxygen throughout the body. And the elemental make-up of these little red round things differed greatly from the surrounding bone and sediment around them.

The next test was looking for heme, a small iron-containing molecule that gives blood its characteristic color and allows hemoglobin proteins to transport oxygen throughout the body. Schweitzer tested for this through spectroscopy tests, which measure the light that a given material emits, absorbs, and scatters. Her results from these tests were consistent with what one would find in heme, suggesting that this molecule existed in the dinosaur bone she was analyzing.

Schweitzer then conducted a few immunology tests to see if she indeed had found hemoglobin in these ancient bones. Antibodies are produced when the body detects a foreign substance that could potentially be harmful. Extracts from the dinosaur bone were injected into mice to see if antibodies were produced to ward against this new organic compound. When these antibodies were then exposed to hemoglobin from turkeys and rats, they bound to the hemoglobin. This suggested that the extracts that caused an antibody response in the mice included hemoglobin. This in turn suggested the T. rex bone contained hemoglobin, or something very similar.

Through years of research, Schweitzer has shown that what was once believed to be impossible is indeed true. Soft tissues, blood cells, and proteins can withstand the test of time. This process is possibly done through iron binding to amino acids (the molecules that make up proteins) and thereby preserve them. Research is advancing in this area, but as of yet, no DNA has been found to bring Jurassic Park to life. But for the avid believer, don’t get up hope yet. Perhaps one day we truly could walk amongst dinosaurs.


References:

Fields, Helen. (May 2006). Dinosaur Shocker. Smithsonian. Smithsonian Magazine.

Pappas, Stephanie. (13 Nov. 2013). Mysteriously Intact T. Rex Tissue Finally Explained : DNews. DNews. Live Science.

Schweitzer, M. (2010). Blood from Stone Scientific American, 303 (6), 62-69 DOI: 10.1038/scientificamerican1210-62

The Olympic Athlete of the Animal Kingdom: The Circulatory System of a Horse (A Guest Post)

By Emily Fandrey


How do you judge the abilities of an athlete? Is it all about speed? What about endurance? Strength? How would you judge an animal that can run up to 48 kilometers per hour (30 mph), cover 48 kilometers (30 miles) in a day, or clear a 2.4 meter (8 foot) jump, all while carrying a human on its back? Because of these abilities, the horse (Equus caballus) is often considered to be one of the animal kingdom’s best athletes. The major factor behind horses’ advanced athleticism is their unique circulatory system, specialized for delivering large amounts of oxygen throughout the body.

Image by Paul Kehrer at Wikimedia Commons.

A horse’s circulatory system has three major players: the heart, the spleen, and the frog (and no, this has nothing to do with the animal frog, but rather a specialized unit of a horse’s hoof). Due to these three components, horses have one of the best aerobic capacities in the animal kingdom. Let’s look at a racehorse for example: During a race, a thoroughbred can reach a maximum oxygen capacity (the amount of oxygen the blood can carry) of 200 milliliters per kilogram per minute, meaning 200 milliliters of blood per kilogram of weight (or 3.1 ounces per pound) are transported to the body every minute! This is more than twice the oxygen capacity of the most elite human athlete!

This diagram illustrates the horse’s circulatory system,
including the heart, arteries, veins, and spleen. Diagram by Emily Fandrey.

So let’s break down this superior aerobic system, starting with the horse heart. Typically, a horse’s heart weighs 1% of its total body weight; meaning if a horse weighs 450 kilograms (1000 pounds), its heart will be roughly 4.5 kilograms (10 pounds). If this was true for humans, a 68 kilogram (150 pound) human’s heart would be 0.68 kilograms (1.5 pounds), although the average human heart is only about 0.23 kilograms (half a pound). The horse’s heart functions very similarly to a human heart. It contains four chambers and is responsible for getting oxygen to the body by pumping the oxygen-filled blood. After the body systems have used the oxygen in the blood, this deoxygenated blood enters the heart and is sent to the lungs where the blood is resupplied with oxygen from breathing air. This oxygenated blood reenters the heart and is pumped back out to the body. Because of the size of their hearts, horses are able to supply large amounts of blood with oxygen to the body with each heartbeat, averaging a combined 38 liters (10 gallons) per minute (this is about ten times as much as a human).

Horses also have very different heart rates than humans during rest and exercise. A horse’s resting heart rate is 28-44 beats per minute (bpm), compared to the average human’s, which is 60-80 bpm. During exercise, a human’s heart rate is 90-170 bpm, depending on age. A horse’s heart rate, however, rises to 80 bpm during a walk, 130 bpm during a trot, 180 during a canter, and 240 bpm while galloping. At top speed, the fast beating heart of the horse is what allows the heart to pump much more blood to the body than a human, increasing their athletic abilities.

A diagram of how the horse’s frog sends blood back to heart quickly,
working against gravity. Diagram by Emily Fandrey.

With the long legs of horses, the heart also has to work against gravity to get blood from the limbs back to the heart. To combat this, the horse has its “frog”. For a horse, the frog is a vessel-filled tissue structure on each of its four hooves. When weight is placed on the frog, this structure can help the heart work against gravity. How? When the horse’s hoof meets the ground, the ground will push up on the frog, resulting in the frog being compressed and squeezing blood in the vessels out and rapidly up the leg. The frog helps heart work against gravity by sending the blood up the leg and back to the heart, allowing for faster blood circulation, increasing the athleticism of the horse.

The last key factor to the horse’s circulatory system is the spleen. This organ improves aerobic capabilities and the horse’s athleticism. Now, the primary function of the horse’s spleen is to remove damaged blood cells. However, when a horse is relaxed, their spleen will fill with up to 30 liters (8 gallons) of oxygen-filled blood. And then, once the excitement of activities like running or jumping sparks, the spleen will contract and send up to 25 liters (6.6 gallons) of this stored blood back into circulation in mere seconds! So in seconds, the spleen is capable of almost doubling the maximum amount of oxygen the blood can carry, increasing the athleticism of the horse as well.

So if you ever need an excelling athlete on your team, consider an animal with a superior circulatory system: the horse. With a large and powerful heart capable of pumping large amounts of blood, a spleen to provide an extra burst of blood in seconds, and a “frog” to work against gravity, there is no wonder why horse is considered to be one of the world’s superior athletes.


References

Allen, K.J., Young, L.E., and Franklin, S.H. (2016). Evaluation of heart rate and rhythm during exercise. Equine Veterinary Education 28: 99-112. DOI: 10.1111/eve.12405.

Cardiovascular System (2007). In EQUINAvet.

Circulatory System of the Horse (2010). In Helpful Horse Hints.

Equine Circulatory System Vet, Horse First Aid (2012). In Equestrian and Horse.

Norton, J. (2013). The equine circulatory system. In EquiMed: Horse Health Matters.

Drinking Beer Makes You More Attractive… To Mosquitoes

Summer is a time of backyard bar-b-ques, camping, baseball games, beer, and mosquitoes. Ugh, mosquitoes! Have you ever noticed that when a bunch of us are hanging out together outside, some of us get eaten alive by those pesky buggers while others are hardly touched at all? It turns out, differences in how much alcohol we have imbibed may be a factor.

An Anopheles gambiae mosquito ready for a meal. Photo by James D. Gathany
at the Public Health Image Library at Wikimedia Commons.

“No! Say it ain’t so!”

I hate to be the bearer of bad news, so I’ll let the scientific evidence speak for itself.

A research team from the French Research Institute for Development, including Thierry Lefèvre, Louis-Clément Gouagna, Eric Elguero, Didier Fontenille, François Renaud, Carlo Costantini, and Frédéric Thomas, and Kounbobr Roch Dabiré, from the Institute for Research in Health Sciences in Burkina Faso set out to test whether people were more attractive to female mosquitoes after drinking a beer compared to beforehand. They only tested females because only female mosquitoes bite, requiring extra protein for their eggs.

The researchers put groups of 50 hungry female mosquitoes into the end of a special Y-shaped maze that let them fly in the direction of one of two odors. At the end of one arm of the Y-maze was a fan, simply blowing outdoor air through a tent and into the apparatus. At the other end of the Y-maze was a fan blowing air through a tent past a shirtless man and into the apparatus. This shirtless man had either not had anything to drink recently, or had recently drunk either a liter of beer or a liter of water. Between the starting chamber and both ends of the arms of the Y-maze were traps that would capture mosquitoes that had chosen to head that direction (lucky for the shirtless men). The number of mosquitoes caught in both traps combined (compared to the total of 50 that was initially released) was called mosquito activation, and reflected how many mosquitoes were motivated to take off and fly upwind. The proportion of mosquitoes caught in the volunteer-bated trap compared to those caught in both traps combined was called mosquito orientation, and reflected the attractiveness of the volunteer’s odor compared to the control odor.

Image A shows the two tents: one in which the man-bait sat (having consumed beer or water), and the other with no one in it. Air from each tent blew threw a tube (seen in picture B) and then into the building, past the traps and into the downwind box, where the mosquito starting-line was located (seen in picture C). Photos from Lefèvre et al., 2010.

The mosquitoes significantly increased both activation and orientation in response to the beer-drinking volunteers, but not in response to the water-drinking volunteers. That is to say, that the smell of someone that has had a beer motivates more mosquitoes to actively pursue them, and makes them more of a focused target of the mosquitoes. The researchers believe there is an interaction between how our bodies naturally smell and how our bodies break down beer that increases the attractiveness of our odors to mosquitoes. People that were more attractive to mosquitoes before they drank were also more attractive to mosquitoes after they drank. But interestingly, people that were warmer or gave off more CO2 were not more attractive to mosquitoes.

You should know that this research is much more important than just being a drag on your summer bar-b-que. The particular mosquito species that these researchers studied was Anopheles gambiae, the primary vector for malaria in Africa. They did this study in Burkina Faso, a country in West Africa with a high rate of malaria, using a local beer called dolo. Dolo, a fermented sorghum beer with low (3%) alcohol content, is the most common alcoholic beverage in Burkina Faso. So if you are in a place with a high rate of malaria, knowing that you should take extra precautions against mosquitoes when you drink could be a life-saver.

Want to know more? Check this out:

Lefèvre, T., Gouagna, L.C., Dabiré, K.R., Elguero, E., Fontenille, D., Renaud, F., Costantini, C. and Thomas, F. (2010). Beer consumption increases human attractiveness to malaria mosquitoes. PloS one, 5(3), e9546.

Mosquitoes Don’t Like Parasites Either (A Guest Post)

By Maranda Cardiel

A photograph of Culex pipiens, the species of mosquito that the researchers used
in their experiment. Source: David Barillet-Portal at Wikimedia Commons.

Everybody hates mosquitoes. They are annoying, persistent, and make us itch like crazy. Sometimes there are so many of them that we are afraid to go outside unless we want to risk getting covered in spots and scratching ourselves all over for the next week. And if that wasn’t enough, they can also carry dangerous diseases with the potential to kill us. However, just like us, mosquitoes don’t like to be bugged by parasites that can make them sick either. Research shows that they may even avoid interacting with hosts that might pass along parasites to them.

A group of researchers - Fabrice Lalubin, Pierre Bize, Juan van Rooyen, and Philippe Christe from the University of Lausanne in Switzerland and Olivier Glaizot from the Lausanne Museum of Zoology – wanted to see if mosquitoes would show a preference for feasting upon birds that were infected with malaria (a blood parasite) or uninfected birds. Mosquitoes find animals to snack on by sensing odors and carbon dioxide in the air that animals give off, along with using their senses of vision, hearing, and touch. In order to figure out if mosquitoes use these senses to specifically choose their unlucky victims, the researchers did an experiment with mosquitoes, malaria, and great tits (a type of bird with a funny name).

For their experiment, the researchers collected mosquito eggs that they hatched and raised in a lab. Only female mosquitoes suck blood, so only female mosquitoes were used in the experiment. The mosquitoes had never been exposed to birds before and were starved of sugar for one day to make sure that they would be hungry. The researchers also caught wild adult great tits, and they took small blood samples from each bird to test for malaria before and after the experiment.

Next it was time to see if the mosquitoes would find some birds to be more appealing than others. A special Y-shaped wind tunnel allowed the mosquitoes to choose between the odors of two birds: one that was infected with the malaria parasite and one that was not. But don’t worry, the mosquitoes could not directly contact the birds. The researchers set up the lab so that it was completely dark to mimic the natural settings of when mosquitoes feed in the wild. This also meant that the mosquitoes were blind and could only choose a bird based on the chemicals in the air. Randomly-chosen pairs of birds and new mosquitoes were used for each round of the test.

A cartoon depicting the experiment setup. A hungry female mosquito hones in on the odors
of a healthy great tit and a great tit infected with malaria parasites. Source: Maranda Cardiel

The results of the study showed that the mosquitoes had a strong preference for birds that were not infected with the malaria parasite. This was true even when the researchers took into account the body sizes and sexes of the birds. Previous studies with different kinds of birds, mosquitoes, and malaria or malaria-like parasites have found similar results. The researchers think that this may be because the malaria parasite somehow causes changes in the chemical processes in the birds’ bodies that the mosquitoes can pick up on.

Infection with malaria might change what the birds smell like to the mosquitoes or how much carbon dioxide the birds give off. There is also evidence that birds who are more susceptible to malaria infections have a different odor than birds with stronger immune systems. But why should mosquitoes be picky and choose to bite healthy birds? They certainly don’t seem like they care whose blood they suck when they are swarming around us!

Previous research has shown that mosquitoes infected with malaria parasites have problems developing their eggs and can have trouble sucking up blood from their victims. Female mosquitoes use blood to nourish their eggs, so if they don’t drink as much blood, they will not be able to lay as many eggs. This means that female mosquitoes carrying malaria parasites are less likely to produce as many healthy offspring. Thus, it makes sense for female mosquitoes to want to avoid feeding on birds that are infected with malaria.

This probably has not changed your thoughts about mosquitoes. They are still a nuisance that we all squish - or at least attempt to squish - upon sight. It might be ironic, but mosquitoes don’t like to have parasites bothering them either. Even though we hate them, maybe now you can find some solace in mosquitoes finding you attractive. It might be a sign that you are actually healthier than your peers.


Source:

Lalubin, F., Bize, P., van Rooyen, J., Christe, P., & Glaizot, O. (2012). Potential evidence of parasite avoidance in an avian malarial vector Animal Behaviour, 84 (3), 539-545 DOI: 10.1016/j.anbehav.2012.06.004

Vampires!

Photo by Alejandro Lunadei at Wikimedia.

Vampire mythologies have been around for thousands of years, terrifying the young and old alike with stories of predatory bloodsuckers that feed on our life essences. You may not believe in vampires, but they are all around us. In fact, you may have some in the room with you right now! You just don’t notice them because they are not human, or even human-like.

Vampires feed on the blood of their victims in order to sustain their own lives. This phenomenon, called hematophagy, is more common than typically occurs to us at first. Just take mosquitoes and ticks as examples. Once we’ve opened our minds to the idea of bloodthirsty arthropods, we quickly think of many more: bedbugs, sandflies, blackflies, tsetse flies, assassin bugs, lice, mites, and fleas. In fact, nearly 14,000 arthropod species are hematophages. We can expand our thoughts now to worms (like leeches), fish (such as lampreys and candirús), some mammals (vampire bats), and even some birds (vampire finches, oxpeckers, and hood mockingbirds). We’ve been surrounded by vampires our whole lives, we just never sat up to take notice!

Hematophagous animals are not as scary as mythical vampires, in part because they don’t suck their victims dry – they just take a small blood meal to sustain their tiny bodies. Hematophagy is not, in itself, lethal. However, the process of exposing and taking the blood of many individuals transmits many deadly diseases, like malaria, rabies, dengue fever, West Nile virus, bubonic plague, encephalitis, and typhus.

Because blood feeders do not kill their meals, feeding can be even more dangerous for them than for traditional predators. As a result, many hematophagous animals have developed a similar toolkit. Many have mouthparts that are specialized to work as a needle or a razor and biochemicals in their saliva that work as anticoagulants and pain killers. Their primary skill, however, is their stealth: they can sneak up on you, eat their meal, and be home for bed before you even notice the itch.

Although a few species, like assassin bugs and vampire bats, are obligatory hematophages (only eat blood), most hematophages eat other foods as well. Somehow, Dracula is not quite so intimidating when you imagine him drinking his morning fruit juice, like many mosquitoes do.

Why drink blood in the first place? Blood is a body tissue like any other, and it contains a lot of protein and a variety of sugars, fats and minerals, just like meat. However, blood is mostly water, which means that a blood meal contains less protein and calories than the same weight of meat. Because you need to consume so much more to get enough protein and calories out of a meal, large animals and animals that generate their own body heat can't usually rely on blood meals alone. So much for human-like vampires that only live off the blood of their victims.

A deadly vampire spreading malaria. Photo by the CDC available at Wikimedia.

So true vampires are everywhere, but they are small, take small blood meals, don't generally kill their hosts, and often use blood to supplement their other meals. Not so scary any more, are they? ...Although, about 3.2 billion people (about half the world's population) are at risk of contracting the deadly disease, malaria, from these bloodsuckers... so maybe you aren't scared enough. Bwaa-haha!

The Weirdest Animals on Earth: 12 Amazing Facts About Octopuses



Photo of a day octopus by
Ahmed Abdul Rahman available
at Wikimedia Commons.

1. The plural of octopus is octopuses. How an English word is pluralized depends, in part, on its origins. Latin words that end in –us are generally pluralized by replacing the –us with an –i (the plural of alumnus, for example, is alumni). But octopus is not Latin – It comes from the ancient Greek word októpous, whose plural is októpodes. Although octopodes is technically correct, since it has been adopted into the English language, the word is now pluralized in the English way, making it octopuses. So octopi is commonly used but not technically correct, octopodes is technically correct but not commonly used and octopussies is just plain wrong.

2. Octopuses are mollusks. This means that they are not only closely related to squid and cuttlefish, but also to clams, oysters, snails and slugs.

3. Octopuses are crazy-smart. They can solve problems, learn from watching others, use tools, and remember experiences. They even have personalities and play with toys. Check this out:

4. Octopuses have nine brains! Rather than a large centralized brain like ours, octopus brains are more like the internet. Their main CPU is a fairly small brain in their head, but each of their eight arms has an additional brain of its own. In fact, two-thirds of an octopus’ neurons are in the arms, which can independently attach to things, push things, and even smell things. They can even react after they have been severed! Not only that, but their severed arms recognize their previous owner:

5. If an octopus loses an arm, it can grow back. Those crazy arms are like the brooms in Disney's Sorcerer's Apprentice in Fantasia!

6. Octopuses are amazing camouflage artists. Their soft bodies can squeeze into ridiculously small cracks and crevices and take on any number of shapes. A 50-pound octopus, for example, can squeeze through a 2-inch hole! They can also change the color and texture of their skin to match their background.

The mimic octopus, the ultimate master of disguise, doesn’t just imitate their background, but also flounders, starfish, poisonous lionfish, and sea snakes.



A vertebrate eye (left) versus an octopus eye (right).
1: Retina, 2: Nerve fibers, 3: Optic nerve, 4: Blind spot.
Image by Jerry Crimson Mann at Wikimedia.

7. Octopuses don’t have visual blind-spots. Most animal eyes detect light patterns when light travels to the retina (the layer in the back of the eye) and falls on photoreceptor cells, causing the cells to send electrical signals through the optic nerve to the brain. Vertebrate photoreceptor cells face backwards, so their nerve fibers come in front of the retina and then exit the eye together through the optic nerve, creating a small region in the back of the eye with no photoreceptor cells. If light falls on this spot, we literally will not see it, although our brain will compensate for this missing light by imagining what should be there based on the rest of what we see. We call this our blind spot. You can test your blind spot by closing your left eye and focusing your right eye on the “R” below. Move your face towards or away from the screen until the “L” disappears. You can test your left eye by staring at the “L” in the same way.

In octopus eyes, the photoreceptor cells face forwards and the nerve fibers go behind the retina. This means that they have a continuous layer of photoreceptor cells and no blind spot.

8. Octopuses are more blue blooded than police officers. Their blood is truly blue, due to the fact that they don’t have hemoglobin, our respiratory pigment that contains iron and turns red when it binds to oxygen. Rather, they have hemocyanin, which contains copper and turns blue when oxygen binds to it.

9. Octopuses have three hearts! They have two small hearts that each pump blood through the gills and a main systemic heart that collects the blood and pumps it through the circulatory system.

10. Octopus ink is a defensive chemical concoction. It not only obscures the view of an attacker, but it also contains a chemical that irritates the predator’s eyes and temporarily paralyzes its sense of smell.

11. Octopuses bite with a bird-like beak and venomous saliva, which is mostly used to subdue prey. Of the approximately 300 octopus species, only the small blue-ringed octopus is known to be deadly to humans.

12. Octopuses die after they mate for the first time. And they mate in an odd way too: males use the tip of their third arm on the right to either insert their spermatophores (sperm packets) directly into the female’s tubular breathing funnel or he just hands it to her (The tip of the third right arm can be used to tell if an octopus is male or female). If he hands it to her, she accepts it with one of her right arms (we don’t know why they’re right-handed this way). Then the males go off to die. The females eventually lay up to 400,000 fertilized eggs, although they can wait months before they do this. She tends them and guards them at the exclusion of all else until they hatch, at which point her body rapidly deteriorates as her cells die off.

Effects of Iron Deficiency in Female Runners (A Guest Post)

By Ana Breit

When people think of nutritional deficiencies, they probably picture women with goiters due to lack of iodine or other newsworthy examples. In reality, the most common nutritional deficiency in the United States is iron deficiency. Iron Deficiency (ID) is especially common in endurance athletes, especially female athletes.


Start of 2013 Roy Griak Invitational Cross Country Meet at
the University of Minnesota. Photo courtesy of Jennifer Larson.

Iron is the metal in humans that allows oxygen to be carried in our bloodstream to all of our other organs. Without enough iron, less oxygen is taken to the muscles and other organs that need it. People with anemia (iron deficiency) may experience fatigue, weakness, and dizziness. Scientists Irena Auersperger, from the University of Ljubljana in Slovenia, Branko Skof and Bojan Leskosek, both from the University Medical Centre in Ljubljana, Slovenia, Ales Jerin, from the University Clinic Golnik in Golnik, Slovenia, and finally Mitja Lainscak, from Campus Virchow-Klinikum in Berlin, Germany asked how iron levels affect performance levels in female runners and whether or not intensified training impacts various iron parameters.

Fourteen moderately active women were chosen to participate in the study. In order to be enrolled they had to have regular menstrual cycles, eat animal products on a regular basis, and not be taking forms of medication except birth control. Each woman was put into one of two groups based on her ferritin levels. (Ferritin is a protein that stores iron). Anyone with ferritin levels greater than 20 micrograms per liter was put in the Normal group (for normal iron stores). Anyone with ferritin less than or at 20 micrograms per liter was put into the Depleted group (for depleted iron stores).

The study took place during a training period leading up to the International Ljubljana Marathon. During the eight week training period, runners had routine tests consisting of a 2400 meter (1.5 miles) time trial on a standard 400 meter outdoor track. Blood samples were taken at three different times: once before the eight week training period, once after the training period, and once more ten days after the marathon. These measurement times will be referred to as baseline, training, and recovery, respectively. Height, weight, and body fat percentage were measured during baseline and at recovery. Each woman then ran on a treadmill so researchers could measure her maximum speed, maximum oxygen consumption (VO2 max), and heart rate. Blood samples were taken at baseline, training, and recovery points to measure various blood parameters and iron parameters.

Both Normal and Depleted groups had similar body measurements, VO2 max, and heart rates. Both groups had improvements in their endurance measurements, however, only the Normal group had endurance improvements that could be documented as significant while the Iron Deficient group’s endurance improvements were less. By the end of the experiment, most of the runners were anemic. Both groups experienced a decrease in iron levels during the training and recovery periods compared with the baseline levels. Overall, both groups’ iron levels decreased in all areas during the training phase, even though they were both getting stronger and faster. The group that started out with lower iron levels did not show as great of an improvement as the group with the normal iron levels at baseline. Even after the 10 day recovery period, iron level parameters were still considered low. With this data, the researchers agree that Iron Deficiency decreases performance levels of female athletes.

Even though most people consider running to be a very healthy pastime, it can have undesired negative effects as well. All endurance athletes, especially female athletes, should have their iron levels checked regularly, and should make a conscious effort to incorporate iron into their hopefully already healthy diet by eating any enriched grains and a healthy amount of red meat. With consent of a physician, iron supplements can also be a good way to keep iron levels in check.

Bibliography

Auersperger I, Škof B, Leskošek B, Knap B, Jerin A, & Lainscak M (2013). Exercise-induced changes in iron status and hepcidin response in female runners. PloS one, 8 (3) PMID: 23472137

The Beginnings of Jurassic Park: Dinosaur Blood Discovered? (A Guest Post)

By Samantha Vold

The classic tale of Jurassic Park, where dinosaurs once again walked the earth has tickled the fancy of many a reader. Dinosaur DNA preserved in a fossilized mosquito was used to bring these giants back to life. But in real life, it was previously thought that there was no possible way for organic materials to be preserved, that they often degraded within 1 million years if not rapidly attacked by bacteria and other organisms specialized in decomposition. Skin and other soft tissues, such as blood vessels, would never withstand the test of time. Or would they…?


T. rex skeleton at Palais de la découverte. Image by David Monniaux at Wikimedia

In 1992, Mary Schweitzer was staring through a microscope at a thin slice of fossilized bone, but this bone had something unusual. There were small red disks located in this tissue and each had a small dark circle in the middle resembling a cell nucleus, the command center of the cell. And these little disks very much resembled the red blood cells of reptiles, birds, and other modern-day vertebrates (excluding mammals). But it wasn’t possible, was it? These cells came from a 67 million-year old T. rex. And it was commonly accepted that organic material never lasted that long.


Comparison of red blood cells. Image by John Alan Elson at Wikimedia

This opened a huge controversy in the scientific community, but Schweitzer persisted. She consulted with her mentor, Jack Horner, a leading scientist in the paleontology field, and he told her to prove to him that they weren’t red blood cells. Schweitzer took the challenge and began to run some tests.

The first clue to these mysterious scarlet-colored cells potentially being red blood cells was the fact that they were located within blood vessel channels of the dense bone that were not filled with mineral deposits. And these microscopic structures only appeared inside the vessel channels, as would be true of blood cells.

Schweitzer then began to focus on the chemical composition of these puzzling structures. Tests showed that these “little red round things” were rich in iron, and that the iron was specific to them. Iron is important in red blood cells as it helps to transport oxygen throughout the body. And the elemental make-up of these little red round things differed greatly from the surrounding bone and sediment around them.

The next test was looking for heme, a small iron-containing molecule that gives blood its characteristic color and allows hemoglobin proteins to transport oxygen throughout the body. Schweitzer tested for this through spectroscopy tests, which measure the light that a given material emits, absorbs, and scatters. Her results from these tests were consistent with what one would find in heme, suggesting that this molecule existed in the dinosaur bone she was analyzing.

Schweitzer then conducted a few immunology tests to see if she indeed had found hemoglobin in these ancient bones. Antibodies are produced when the body detects a foreign substance that could potentially be harmful. Extracts from the dinosaur bone were injected into mice to see if antibodies were produced to ward against this new organic compound. When these antibodies were then exposed to hemoglobin from turkeys and rats, they bound to the hemoglobin. This suggested that the extracts that caused an antibody response in the mice included hemoglobin. This in turn suggested the T. rex bone contained hemoglobin, or something very similar.

Through years of research, Schweitzer has shown that what was once believed to be impossible is indeed true. Soft tissues, blood cells, and proteins can withstand the test of time. This process is possibly done through iron binding to amino acids (the molecules that make up proteins) and thereby preserve them. Research is advancing in this area, but as of yet, no DNA has been found to bring Jurassic Park to life. But for the avid believer, don’t get up hope yet. Perhaps one day we truly could walk amongst dinosaurs.


References:

Fields, Helen. (May 2006). Dinosaur Shocker. Smithsonian. Smithsonian Magazine.

Pappas, Stephanie. (13 Nov. 2013). Mysteriously Intact T. Rex Tissue Finally Explained : DNews. DNews. Live Science.

Schweitzer, M. (2010). Blood from Stone Scientific American, 303 (6), 62-69 DOI: 10.1038/scientificamerican1210-62

Is That Lizard Possessed!? (A Guest Post)

By Tawny Liebe

Image from Chuck Heston on Flickr.

A creature straight from the depths of hell… or at least as close as you can get on this planet. The Texas horned lizard or “horny toad” is found in the deserts of the southwest United States and has an unusual adaptation to deter predation exclusively from a few species of canines. When threatened by coyotes, foxes, and dogs, the horned lizard squirts blood from its eyes to hit targets up to three feet away! A total of six species of horned lizard have been proven to respond this way to canine attack, while none have responded this way to other predators, such as the grasshopper mouse or the roadrunner. So what is the deal? How do they do this and how does it work as predator defense?


Veins have one-way valves
to prevent backflow.
Drawing by Tawny Liebe.

Before we get to that, there are a few things you need to know. First of all, the circulatory system includes a network of arteries and veins. Arteries carry blood full of oxygen to body tissues while veins carry blood that lacks oxygen from the rest of the body back to the heart. This means that for the blood, in someone’s foot for instance, to get all the way back to the heart through the veins, the blood must work against gravity. When you (or this lizard or many other species) move, blood is propelled from one chamber in the vein to the next until it reaches the heart. The blood is prevented from flowing back into the previous chamber by one-way valves, causing the blood to pool.

In order to squirt blood from their eyes, horned lizards manipulate the network of veins in their head so that they build up pressure, like a volcano getting ready to blow. By constricting a pair of throat muscles unique to reptiles, they effectively close their jugular veins and increase the blood pressure in their head. This is thought to be enhanced by another pair of muscles between the jugular veins and the eyes that help increase the blood pressure in the head even further, causing the blood to move into the sinuses of the eyes. The pressure continues to build until the blood breaks through the wall of the eye socket into the eyelids where it is forced into the tear duct and erupts like a Mentos in a Coke bottle all over whatever is chomping at the poor little lizard.

As if these lizards couldn’t get any more amazing, recent studies have shown that it is actually a compound in their blood that canines don’t like. Scientists have also found that this chemical is in their circulating blood, not just the blood that is squirted from their eye, rejecting an earlier hypothesis that the chemical is picked up in the tear duct. To top off all of this awesomeness, the chemical may be acquired through its main food source- harvester ants, which are venomous. These ants aren’t actually a requirement of the horned lizard’s diet and yet they are specialized to eat them. The horned lizard’s blood plasma binds to the venom, which neutralizes its toxicity and the resulting compound may be what deters these canines.

Now that we know how horned lizards are capable of this type of defense and how they most likely make their blood so undesirable, what is it about this chemical that is so appalling to these predators? It appears that the target area of the blood is the mouth since the horned lizard only squirts the blood when the canine begins to bite down on its head. This suggests that it may be the taste of the blood that prevents the horned lizard from becoming that coyote’s tasty snack.

The horned lizard’s ability to squirt blood at canines to prevent their untimely death is truly amazing and complex and there is still much to learn about it. Their ability makes me wonder how many other cool anti-predator adaptations there are out there in the animal and even the plant kingdom! Below is a video that will allow you to appreciate the full effect of this awesome defense strategy, enjoy!

References:

Heath, J.E. 1966. Venous shunts in the cephalic sinuses of horned lizards. Physiological Zoology 39(1): 30-35.Middendorf, G.A. and Sherbrooke, W.C. 1992. Canid elicitation of blood-squirting in a horned lizard (Phrynosoma cornutum). Copeia 1992(2): 519-527.

Middendorf, G.A. and Sherbrooke, W.C. 1992. Canid elicitation of blood-squirting in a horned lizard (Phrynosoma cornutum). Copeia 1992(2): 519-527.

Middendorf, G.A. et. al. 2001. Comparison of blood squirted from the circumorbital sinus and systemic blood in a horned lizard, Phyrnosoma cornutum. The Southwestern Naturalist 46(3): 384-387.

Middendorf, G.A. and Sherbrooke, W.C. 2004. Responses of kit foxes (Vulpes macrotis) to antipredator blood-squirting and blood of Texas horned lizards (Phrynosoma cornutum). Copeia 2004(3): 652-658.

Sherbrooke, W.C. 1992. Chiricahua Mountains Research Symposium. Horny “toad” tales from the Chiricahua mountains as, told by a biologist. Southwest Parks and Monuments Association, Tuscon, AZ. 78-80.