White's Tree Frog

The Eatles have been busy munching away for the first time on a non-mammal vertebrate! Specifically, they are devouring the soft tissue remains of a White's Tree Frog (Litoria caerulea) from Grant's Farm in St. Louis, MO, named Nona.

White's Tree Frog. Photo from Animal Diversity Web.

Also known as the Smiling Frog, and the Dumpy Frog, this animal is fascinating. It belongs to the Hylidae family of frogs, which is an interesting group because it is united by a single morhpological character shared by all of its members (well, almost all...): claw-shaped terminal phalanges (bones of the fingers and toes). White's tree frogs are native to Australia, Indonesia, and New Guinea, and they live mostly in rainforests and coastal areas. They are usually bright green in color (before The Eatles get ahold of 'em), although the color of their skin can range from brown to light blue and even gray. These frogs are arboreal, as their name implies, and therefore their diet consists largely of insects like moths, locusts, and roaches. But that's not all! They also are known to eat other animals like spiders, worms, and even small mammals (rodents). Because their diet is varied, it is not surprising that they have multiple modes of prey capture. To capture small prey like insects, these frogs extend their sticky tongues and reel in the catch; but to capture larger prey like mice, they will pounce on their victim and force it into their mouth with their hands - much like college students devouring a pizza after a long night at the bar or Buddy the Elf...
 

One of the most interesting aspects of these animals, however, is their skin. Like all amphibians, they have thin, moist skin that can be easily penetrated by gasses and liquids. This allows them to breathe underwater through gas exchange, without aspirating fluid into their lungs. But the skin of the White's tree frog also possesses a waxy cuticle that prevents water evaporation, which enables it to live in areas farther from a water source, like arid regions or even inside someone's house (they are frequent house "guests" in Australia). The waxy cuticle is interspersed with skin glands that also help to keep it moist. Even more interesting than the waxy cuticle is the fact that the skin secretes a protein that is effective in killing the bacteria Staphylococcus aureus and also in lowering human blood pressure.

We hope you've enjoyed this little diversion into the amphibian world. We are excited to be fostering new relationships with local animal advocacy groups that will lead to more interesting animals being fed to The Eatles. More to come soon, we promise!

Contributed by: Jason Organ, PhD

If you want to read more about White's tree frogs, these papers are a good place to start: 

Boland MP, & Separovic F (2006). Membrane interactions of antimicrobial peptides from Australian tree frogs. Biochimica et biophysica acta, 1758 (9), 1178-83 PMID: 16580625  

Campbell CR, Voyles J, Cook DI, & Dinudom A (2012). Frog skin epithelium: electrolyte transport and chytridiomycosis. The international journal of biochemistry & cell biology, 44 (3), 431-4 PMID: 22182598  

Manzano AS, Abdala V, & Herrel A (2008). Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability? Journal of anatomy, 213 (3), 296-307 PMID: 18565111

Domestic Dog - Osteoporosis Research

The evolutionary origin of the domestic dog (Canis lupus familiaris) is not well understood. DNA evidence suggests that the domestic dog diverged from its closest relative, the grey wolf (Canis lupus), sometime between 11,000 and 16,000 years ago, although a recent report pushes this date back to at least 27,000 years ago, which is in closer accord to the archaeological evidence that suggests a divergence around 36,000 years ago. And of course, once we humans assert our dominance over another species, we begin to tinker with it, in order to improve it. Today, the World Canine Organization (Federation Cynologique Internationale) recognizes over 340 breeds of domestic dog.

The most common breed of dog used in biomedical research is the beagle, and our laboratory is no exception. The Organ Laboratory does not take animal research lightly. Like every other laboratory at Indiana University School of Medicine, before we begin a study we are required to submit an animal protocol for review by the Institutional Animal Care and Use Committee (IACUC). The IACUC is comprised of university leaders, other researchers, veterinarians, and members of the general public. Every single procedure we wish to perform in an experiment must be approved by the IACUC prior to the initiation of the experiment. THIS. IS. CRITICAL. It is critical because animals, unlike people, are not able to give their informed consent to a procedure. Therefore, the IACUC assures that these animals will experience the least amount of discomfort and stress during any procedure. In fact, it is not uncommon to have more difficulty getting an animal study approved than it is to get a study approved for humans. Again, this is because humans can refuse to participate in a study, whereas a laboratory animal cannot. Because we study the mechanical properties of bone and muscle in a biomedical context, our work could not proceed without the use of vertebrate animals. Typically, our studies are carried out using laboratory rodents such as mice and rats because a whole lot is known about the genetic makeup of these animals, and we can control more variables because we can measure them with species-specific tools like biomarkers and DNA. Unfortunately, and perhaps due in part to size constraints, mouse and rat bone are inferior models of human bone. Why is that? Allow us to digress for just a moment…

Bones are dynamic tissues, and they are constantly remodeling out the numerous micro-cracks that materialize from normal wear and tear. This remodeling occurs when osteoclast cells resorb the bone matrix and osteoblast cells synthesize and lay down new bone where the old bone was removed. There are multiple places (envelopes) on any given bone where this type of activity occurs. One of the most important areas in human bone is the cortical shell surrounding the marrow cavity. Human cortical bone experiences a lot of intra-cortical remodeling, activity within the middle of the cortex.  Contrast this with rats and mice which typically only remodel on the inner and outer surfaces of cortical bone. Therefore, rodents make a poor research model if the question to be answered focuses on intracortical remodeling. Beagles, and dogs in general, do experience intracortical remodeling, and thus they are suitable animal models of human cortical bone.

The ultimate goal of the research described here utilizing a dog model is to improve treatment of osteoporosis by treating the underlying mechanisms that lead to fracture. Our most recent studies have investigated whether combining different types of anti-osteoporosis drugs might be more beneficial than using either one of the drugs alone. In particular, we combined two different classes of anti-catabolic drugs, meaning that these drugs prevent the loss of bone. There are two different classes of anti-catabolic agents used to treat metabolic bone diseases: bisphosphonates and selective estrogen receptor modulators (SERMs). Through our experiments, we have made several significant findings. Below, we highlight two of them.

First, we showed that 6 months of daily raloxifene treatment improves bone material mechanical properties as measured with reference point indentation (RPI). RPI is a novel tool used to assess mechanical properties of bone in vivo and has shown some ability to distinguish between fracture and non-fracture patients when used clinically. We were very excited to discover that raloxifene was effective in enhancing skeletal mechanical properties because we know the drug has little effect on bone mineral density. Subsequent studies utilized the same set of dogs to demonstrate that raloxifene increases cortical bone matrix-bound water, essentially increasing the hydration of the bone, and therefore increasing its material toughness. We hypothesize that this altered hydration is related to the known anti-fracture efficacy of raloxifene. Voila! A mechanism of action!

Some of the skulls in our outreach collection.

Once The Eatles are finished cleaning this skull, we will add it to our growing collection of animal skulls that we use for outreach programming. Over the years we have developed a number of initiatives that bring skeletal biology and functional anatomy to the classroom, and we can aim our programs for any grade level from preschool to high school. If you are in central Indiana and are interested in having one of us visit your classroom, please get in touch on twitter: @eatlemania

Contributed by: Neil Jain, Kelly Biro, and Jason Organ, PhD

References:

Allen MR, Territo PR, Lin C, Persohn S, Jiang L, Riley AA, McCarthy BP, Newman CL, Burr DB, & Hutchins GD (2015). In Vivo UTE-MRI Reveals Positive Effects of Raloxifene on Skeletal-Bound Water in Skeletally Mature Beagle Dogs. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 30 (8), 1441-4 PMID: 25644867

Allen MR, McNerny EM, Organ JM, & Wallace JM (2015). True Gold or Pyrite: A Review of Reference Point Indentation for Assessing Bone Mechanical Properties In Vivo. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 30 (9), 1539-50 PMID: 26235703 

Aref M, Gallant MA, Organ JM, Wallace JM, Newman CL, Burr DB, Brown DM, & Allen MR (2013). In vivo reference point indentation reveals positive effects of raloxifene on mechanical properties following 6 months of treatment in skeletally mature beagle dogs. Bone, 56 (2), 449-53 PMID: 23871851

Skoglund P, Ersmark E, Palkopoulou E, & Dalén L (2015). Ancient wolf genome reveals an early divergence of domestic dog ancestors and admixture into high-latitude breeds. Current biology : CB, 25 (11), 1515-9 PMID: 26004765

Eatlemania Hits the Airwaves!

We are so excited to announce that you can now watch The Eatles munching the night away in real time at the Organ Laboratory YouTube Channel.

Immediately you will notice three "dishes" they are feasting on (from closest to farthest from camera):

1) Thanksgiving turkey (Meleagris gallopavo) remains from my mother in law's kitchen! In our family, thanksgiving is a time for sharing with family and friends and beetles. In keeping with the outreach spirit, our colleague at IU School of Medicine, Dr. Bill Sullivan, recently wrote about some interesting turkey facts at The 'Scope. Enjoy.

Winner Winner Turkey Dinner

2) "St. Louis style" spare pork (Sus scrofa) ribs from City BBQ. As a big fan of barbecue, I was surprised to learn that "St. Louis style" ribs has nothing to do with being coated in sticky barbecue sauce, and everything to do with the actual cut of meat. "St. Louis style" ribs are the spare ribs and are usually meatier and have higher fat content that baby back ribs (or loin ribs). The more you know...

I want my baby back, baby back, baby back spare ribs.

3) Amber the hedgehog, who is slowly but surely being cleaned for us by The Eatles.


We hope you enjoy watching!

Contributed by: Jason Organ, PhD  

Little Brown Bat

Myotis lucifugus. Photo from Animal Diversity Web

Over the last week, the Eatles have completely devoured the soft tissue remains of a little brown bat (Myotis lucifugus), with a great big story. Well, maybe neither "big" nor "great"... but certainly a "good" story. In Summer 2010 we attended the birthday party of a family friend's toddler. The party was thrown at the birthday boy's grandparents' farm located in Sullivan, Missouri, about 65 miles SW of St. Louis.

As a comparative anatomist by training, I have been fortunate to learn so much intricate, detailed anatomy through dissection. However, with that fortune sometimes has come the misfortune of using specimens that were less than fresh - ripe, even. When we arrived at the birthday, I noticed the very faint, but unmistakable, stench of decomposition wafting from under the picnic table where the birthday cake was set. I looked under the table and found a recently deceased little brown bat. I discreetly informed the party host of my find, and as any self-respecting comparative anatomist would do, I asked if I could take it home! So my friend the little brown bat from Sullivan stayed in my lab chest freezer for the next five and a half years awaiting his fate at the hands of The Eatles.

Bats belong to the mammalian order Chiroptera, which is the second most speciose group of mammals after rodents (Order Rodentia). Chiroptera is divided further into two groups of bats: the mega bats - the large Old World fruit bats; and the micro bats - the small, generally insectivorous bats. The little brown bat belongs to the microchiropteran family Vespertilionidae, which includes over 300 species of common bat.

Little brown bat feast

Bats are fascinating creatures. Most vespertilionids navigate by utilizing a combination of eye sight and echolocation. In order to echolocate, bats create a series of high-pitched sound pulses at frequencies that their sense of hearing is optimized to detect (usually well above the range of human hearing). These sound pulses originate in the animal's larynx (vocal apparatus) and resonate through the nose and mouth. The sound pulses reflect off of objects in the distance, and the echo that returns indicates how far away the object is, such as food or trees or another bat. These echoes can also help the animal determine how large the object is, and whether or not it is moving, which is helpful for finding potential mates and prey, and for avoiding predators. You can read more about echolocation in bats at the Bat Conservation Trust.

Little brown bats are small in size, averaging somewhere between 5 and 14 g in weight and between 60 and 100 mm in length (head to tail), with a wingspan that is 222 to 269 mm. They live all over North America except in the forested high mountains of Mexico, and their diets consist largely of insects such as moths, wasps, beetles (oh no... please NOT BEETLES!), mosquitos and mayflies. Unlike many bats, little brown bats do not migrate long distances to warmer climates during the winter. Instead, they move their roost sites to places where outside temperatures can be modulated in colder temperatures, such as inside abandoned mine shafts or caves, usually within 100 miles of their summer roosting sites.

Upper Limb Skeletal Homology, Arizona State University.

But probably the most fascinating thing about bats is that they are the only living mammals that have evolved anatomical adaptations for sustained flight. The basic elements of the mammalian upper limb musculoskeletal system are present in bats, although they have been significantly modified to support a wing membrane (patagium), and the sizes of many of the bones and muscles differ from those of nonflying animals. For example, the distal elements of the upper limb - the metacarapal bones of the hand and the phalanges of the fingers - have been elongated in order to provide support for the patagium and to control its movements. The patagium, which is a double-layered membrane of skin derived from the abdomen, encloses a series of nerves, blood vessels, and muscles, and it extends from a bat's fingers to the torso and abdomen and to the lower limb. In order to support the patagium with the lower limb, a bat's hip joint is rotated 90° so the knee faces backward. This altered hip joint prevents normal walking in bats, but also allows the bat to hang upside down in its roost. Upside down hanging is also helped by a tendon configuration in the toes that locks their toes in place so they can continue to hang without conscious effort during sleeping.
 
Contributed by: Jason Organ, PhD 

Read more about bat science in these references:

Dzal YA, & Brigham RM (2013). The tradeoff between torpor use and reproduction in little brown bats (Myotis lucifugus). Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology, 183 (2), 279-88 PMID: 22972361 

Fenton, M., & Barclay, R. (1980). Myotis lucifugus Mammalian Species (142) DOI: 10.2307/3503792

Veselka, N., McGuire, L., Dzal, Y., Hooton, L., & Fenton, M. (2013). Spatial variation in the echolocation calls of the little brown bat ( ) Canadian Journal of Zoology, 91 (11), 795-801 DOI: 10.1139/cjz-2013-0094

African Pygmy Hedgehog (Four-Toed Hedgehog)

From 2008-2012 our lab was located at the Saint Louis University School of Medicine. We spent four years there studying the comparative anatomy of primates before venturing into our biomedical research areas when we moved to Indiana University. During our time in St. Louis, we established a collaboration with Jenny Joyce, the Elephant Manager at Grant's Farm. Grant's Farm is the 281-acre ancestral home of the Busch family (of Anheuser-Busch fame) and is named after Ulysses S. Grant, the 18th President of the United States, who had previously worked a portion of the land. Today, Grant's Farm is a well regarded wildlife park dedicated to education and public outreach about the 900 different species that call the park home. Our collaboration with Jenny allowed us to obtain remains of animals that died of natural causes at the wildlife park, and we are greatly appreciative.

One of the animals that came to us from Grant's Farm was an African pygmy hedgehog (Atelerix albiventris) named Amber. Given the association with Anheuser-Busch, it should come as no surprise to beer connoisseurs that Amber had a brother named Bock.

Photo from University of Michigan's Animal Diversity Web (animaldiversity.org)

African pygmy hedgehogs are members of the mammalian Order Insectivora, which includes hedgehogs, moles, tenrecs, golden moles, solenodons, and shrews, divided among six families (African pygmy hedgehogs belong to the family Erinaceidae). They are generally solitary animals that range in Southern Africa from Senegal to Sudan to Zambia, and live in deserts and scrub forests. They feed mostly on insects and spiders, and for a long time were brought out of Africa by pet traders - this is no longer legal, however. One of the most distinctive aspects of this animal is the presence of sharp quills covering its back and sides. These quills are present at birth but covered in a membrane that prevents them from injuring the mother during delivery. When a hedgehog is threatened by a predator it has the ability to roll itself into a tight ball, which forces its quills to splay in all directions and protects the animal from being eaten.

The Eatles have been feasting on the remains of Amber for the last several days, and they are making quick work of cleaning her skeleton. Below is a picture from this morning. I will post additional pictures as they progress, and of course will be sure to post a picture of the final product.

Contributed by: Jason Organ, PhD 

Read more about African Pygmy Hedgehogs:

Nichols, J. 1999. "Atelerix albiventris" (On-line), Animal Diversity Web. Accessed January 13, 2016 at http://animaldiversity.org/accounts/Atelerix_albiventris/

Girgiri I, Olopade JO, & Yahaya A (2015). Morphometrics of foramen magnum in African four-toed hedgehog (Atelerix albiventris). Folia morphologica, 74 (2), 188-91 PMID: 26050805 

Girgiri, B., Ibrahim, B., & Bwala, A. (2015). Morphometric studies of some visceral organs and gastrointestinal tract of four-toed african hedgehog (atelerix albiventris) Journal of Morphological Sciences, 32 (1), 29-32 DOI: 10.4322/jms.071014