Celiac Disease and Adherence to a Gluten Free Diet

An autoimmune disease is a disease in which the body produces antibodies that attack its own tissues, leading to deterioration and destruction of said tissue. Celiac disease is one of these bodily disorders, in which the villus of the small intestine is severely damaged when the protein gluten is consumed. For ultimate restoration of this digestive organ, it is imperative that diagnosed individuals adhere to a gluten free diet.

The G Word

What is gluten you ask? Gluten is the common name for two proteins, glialdin and glutenin, found in barley, wheat, and other popular grains. These compounds are commonly found in bread, pasta, cereal, baked goods, and popular liquids. Gluten, the most consumed protein, forms when the chemical bond is formed between glialdin and glutenin.

Celiac Disease

It is very important to understand what makes up gluten for future studies and potential medicinal options for individuals who are diagnosed with celiac disease. Celiac disease is unlike any other autoimmune disease because the trigger is environmental and a human leukocyte must be present. What is meant by this is that the trigger is due to exposure to an irritant, and that the disease is strictly hereditary. Within diagnosed individuals glialdin and glutenin are deemed toxic and disturb the lining in the small intestine. This disturbance results in a reaction against the two compounds, resulting in anatomical problems such as villi atrophy. Villi atrophy is the loss of absorption ability in the small intestine.

Call the doctor

In addition to villi atrophy, other symptoms arise in an individual who is diagnosed with celiac disease. These symptoms can be nutritional or gastrointestinal. Nutritional problems include such as anemia and vitamin D deficiency, while gastrointestinal symptoms include bloating, diarrhea, excessive gas, and abdominal pain. When celiac disease is found in children, adolescents will be smaller in height and/or weight, while adults are diagnosed after uncontrollable diarrhea in addition to osteoporosis. Some psychiatric disorders may be present among the diagnosed including depression, anxiety, and irritability. In an experiment preformed on three hundred individuals, one hundred had celiac disease and within the diagnosed, fifty percent had neurological abnormalities.

They Have to do what?!

As an individual experiences these symptoms, diagnosis of celiac disease is performed by a procedure called a biopsy. A biopsy begins with a local anesthetic sprayed on the throat of the patient to provide local numbing. A physician then inserts the tube into the mouth, and down the esophagus until the tube reaches the stomach. A small syringe that is within the tube, obtains a sample by cutting a piece of tissue off the intestinal lining. The tube is extracted back through the esophagus and the sample is analyzed. Samples are stained with various solution dyes, and examined under microscopes for villi atrophy. Villi atrophy is displayed as positively stained cells on the exterior layer and found as deep as the basal layer of the lining.

A second way one would test for celiac disease is serological testing. This test is performed in individuals who experience malabsorbtion, osteoporosis, or are high risk for the disease, such as immediate family members of a currently diagnosed patient. These tests display the presence of the HLA DQ2 or HLA DQ8 antigen that is always seen in the disorder. Once a positive diagnosis has occurred, unfortunately there is only one available treatment for the disease.

Kiss me, I’m gluten free

Today the only way to cope with celiac disease is to comply with a gluten free diet. Although it is the only option for these patients, those who are complying with this diet are at risk of zinc and iron deficiencies, as well as loss of vitamins such as K, A, and E. In multiple studies, adherence to a gluten free diet restores villi to a normal level and decreases symptoms ten fold.

Adherence to a gluten free diet is essential but the recovery time of the small intestine varies from person to person. Discussed in Lee et al. 2002, duodenal biopsies were taken from thirty-nine patients to examine anatomical improvement to a gluten free diet for roughly eight years. After the collection of samples, it was discovered that normal mucosa appeared in 23% of the individuals and 46% had visible damage with improved lining. According to the results of the mentioned experiment, adhering to a diet that is gluten free will restore intestinal damage and relieve symptoms from the diagnosed.

What Next?

Although the gluten free diet is the only available treatment for celiac disease, there is research happening to find other options and potentially a cure. The Kansas Wheat Commission is spending over two hundred thousand dollars on an attempt to grow gluten free wheat. Research is not only being done on food, but on mice as well. Bana Jabri, MD is the lead researcher at the University of Chicago’s Celiac Disease Center and has constructed a model that consists of genetically modified mice that display the same symptoms as humans who have the disease. Her campaign received a two million dollar investment and hope to provide new treatments and therapies for the disease. Celiac disease is being diagnosed more now than in previous years, but with technological advancement, those diagnosed may no longer have to comply with a gluten free diet in the near future.

Improving Health and Preventing Disease: anaerobic exercise & insulin sensitivity

Everyone likes his or her dose of sugar. Most people would prefer to eat candy or ice cream instead of eating vegetables. Many individuals also make up every excuse in the book to justify skipping the gym. But what is this doing to our bodies? An unhealthy diet and sedentary lifestyle are both major factors in becoming more resistant to a hormone known as insulin. Being resistant to insulin is associated with many health issues and is the primary factor in developing type II diabetes. Therefore, it is imperative to increase your body’s sensitivity to insulin. Anaerobic exercise can significantly increase the body’s sensitivity to insulin improving health and preventing disease such as type II diabetes.

What is Insulin Sensitivity?

Insulin sensitivity is your body’s responsiveness to the fuel source glucose. Glucose is a sugar and is a major source of energy for our body. It is obtained through eating carbohydrates such as pasta, bread, beans, and fruits. When you eat a carbohydrate, it will be broken down by your digestive system and results in glucose being released into your bloodstream. Your body registers that glucose levels are increased in the blood stream and your pancreas releases a hormone called insulin. Insulin’s job is to direct the cells to use the glucose from the blood stream for fuel. Insulin then stores any glucose that is left over as fat to be used later for energy. When excess insulin is circulating in the blood stream it can cause health issues such as damaged blood vessels, cancer, obesity, high blood pressure, and heart disease. It is important to be sensitive to insulin because it will improve your body’s efficiency to the hormone, which will reduce the amount of insulin circulating in the bloodstream, preventing health issues.

What causes the body to become resistant to insulin?

Every time a cell comes in contact with insulin, the cell becomes more resistant to it. This is an unavoidable reason that people become more resistant to insulin as they age. However, there are also risk factors in becoming resistant to insulin that can be avoided such as a high body fat percentage, a decrease in muscle mass, an unhealthy diet, a sedentary lifestyle, and a low level of overall fitness. Even though there is no way to change the fact that we age, preventative measures to increase insulin sensitivity are possible.

How can you become more sensitive to insulin with anaerobic exercise?

Maintaining a healthy diet and a low body fat percentage are important factors for increasing insulin sensitivity. Anaerobic exercise is also a well-known way to increase insulin sensitivity. Anaerobic exercise is any short duration activity in which the body does not use oxygen to fuel metabolic activity. Bodybuilding, sprints, and resistance training are all examples of anaerobic exercise. Anaerobic exercise has both a direct and indirect impact on insulin sensitivity. It has an indirect impact because exercise helps maintain low body fat percentage, increase muscle mass and strength and an overall better level of physical fitness. It has a direct impact because of the role anaerobic exercise has on glucose metabolism.

What role does glucose play in anaerobic exercise?

The next time you get a personal record while performing a bench press, you can thank glucose. Glucose is the starting point for the anaerobic mechanism responsible for causing muscle contraction. Without glucose, your muscles would not be able to contract and you would not be able to exercise. After anaerobic exercise, your muscles have an increase glucose uptake due to increased activation and expression of proteins that are involved in bringing glucose into the muscle. This increase in activation and expression of these proteins takes away some of the responsibility of insulin’s job. By being more active, it makes it easier for glucose to be transported from the bloodstream into the muscle. Since these proteins function better, it requires less insulin to help direct the glucose into the cells. Therefore, exercise increases insulin sensitivity because of an increase in glucose uptake and due to the proteins involved in transporting glucose, are more active and expressed. This was first shown in a study looking at the effect of exercise in rats on the expression and activity of these proteins. In this experiment, one group of rats was put through bouts of exercises to see how they compared to a group of sedentary rats. In the end, the experiment found that the group of rats that exercised had an increase in insulin sensitivity due to this increase in activation and expression of these proteins.

What does this mean for you?

Besides maintaining a healthy diet and low body fat, you should perform anaerobic exercise to increase insulin sensitivity. Whether you would like to lift weights or go do some sprints, you should do some form of anaerobic exercise on a regular basis. Long-term exercise can result in a sustained increase in insulin sensitivity to prevent and treat insulin resistance. This can prevent and treat many health issues associated with a decreased sensitivity to insulin including type II diabetes, obesity, high blood pressure, and heart disease. If that is not enough to get you to exercise, keep in mind, exercise will also make you look much better at the beach.

Struggling fish take out third mortgage to put sons through daycare

The cost of living seems to rise steadily every single year, and as a result, parenting is more expensive than it has ever been. The price of college tuition is at an all-time high, and these days it feels like a mandatory destination in terms of competing in the job market. The time and energy that must be invested when caring for a child is also nothing to scoff at. A legitimate cost of parental care is the sacrifice of what could have been done with that time and energy. There are countless instances of parents who were destined for exciting careers and lifestyles and gave it all up for the sedentary ways of family life. For these parents, all decisions are made with the thought of their children in mind.

Animals also demonstrate a considerable amount of sacrifice for their offspring. Just think about the times you’ve witnessed a feral mother putting herself at harm to protect her offspring. I have personally experienced this in my childhood when I witnessed wild turkey chicks roaming on our lawn. The first instinct of me and my siblings was to capture the cute chicks and keep them as pets. I approached the chicks, but before I could catch them, the mother turkey charged at me and I ran away. When I reached the top of my deck and looked back to see the mother guiding her chicks into the forest I reflected on what just happened. Wait a minute, I thought. I’m way bigger, faster, and stronger than that stupid turkey. I could kill her with one swift kick of the foot, yet she still charged at me. That turkey put its own life at risk in order to protect her chicks, and while it was quite dangerous, it was also valiant.

Wild turkey protects her chikcs

In that case, the cost of raising children extended beyond the loss of resources. It included the mother putting herself in danger, something that is seemingly counter intuitive in the animal kingdom. Is it just plain love, or were there some instinctual reasons behind the action of that turkey? In order to answer this question, we can ask the most ancestral species that engaged in parental care in the animal kingdom, the fish. Fish were busting their butts for their offspring long before man ever walked the earth. They exhibit a primitive type of parental care known as brooding, meaning that they protect, and incubate their eggs before and sometimes even after they hatch. Cichlid fish specifically are known for this type of behavior, and different species engage in different levels of care which come with different degrees of sacrifice. For example some species may hold their eggs in their mouths while others may protect them in caves. Both activities require an increase of resources. Some species have such a difficult time acquiring resources while caring for their eggs, that they recruit other cichlids to care for their offspring. In fact, my buddy was just telling me the other day that his coworker, who happened to be a cichlid fish,sold his house in order to pay for its offspring’s daycare! Joking aside, these fish do in fact relinquish territory as payment for foster care. It’s just one among many costs of parental care.

The cost of resources is the most visible cost of parental care. Oxygen is often a limiting resource in cichlid habitats, just like money or food in human society. There are two ways a cichlid fish can breathe. They can either use their gills and breathe under water, or they can swim to the surface and breathe with their mouths. Under normal circumstances, the former is preferred because staying underwater reduces the chances of encountering an aerial predator. However, when fish are brooding and require more oxygen, they will often take that risk and breathe at the surface.

There is also the need for food. Unsurprisingly, it’s actually quite difficult to forage for food while eggs are brooding in your mouth. So what do these fish do? They partner up and take turns. A mother and father will cycle between who watches the eggs and who goes out in search for food! Cichlids have even been observed fighting over whose turn it is to watch the eggs (spoiler alert, the male usually loses and has to watch the eggs). Increases in stress levels have been measured in fish that go to these lengths to care for their eggs, and sometimes they even die as a result of raising their children.

Two cichlid parents gaurd their eggs

Lastly, we can’t mention the sacrifices of fish parental care without looking at the opportunity cost of investing time in their children. In fish society, polygamy, or mating with multiple partners, is the standard of success. It’s all about spreading your seed, and brooding fish are off the market. Moreover, after the fish have completed brood care and their eggs have hatched, they become less desirable than they were beforehand. This happens because of two things. First, the stress of parental care often causes cichlid fish to shrink in size. Small fish are less desirable than big fish and have a harder time attracting mates. Small fish are also more likely to be exposed to predators and aggression from other fish. Second, brooding fish often sacrifice their territories in order to search for mates and don’t typically regain territory while brooding. After brood care is complete, they are left in search for territory which they may or may not find. These factors make the process of mating a second time much more difficult.

Parent surrounded by offspring

So why do they do it? It’s not as if the fishes’ offspring appreciate the time and energy their parents invested in them. Although there aren’t any direct benefits of parental care for the parents, there is one major benefit for the offspring. Fish that protect their eggs with brooding decrease the likelihood that predators will find and eat their offspring. In other words, parental care in fish is a behavior that was evolved for the perseverance of their species.

Just as we see in fish, caring for children often drains the time, energy and prospects of human parents. And just like we see in fish, we can’t necessarily expect children to appreciate the sacrifices that parents make. In both fish and humans, parental care is a necessary responsibility that helps ensure the success of our future generations. Offspring may not always appreciate their parents, but biologists do!

Sea Otters: the Cuddly Key to Marine Ecosystem Health

Sea-Otter-LeDent Who doesn’t love sea otters? Anyone who has mindlessly browsed the internet has probably stumbled across pictures or videos of sea otters. Usually they’re holding each other’s paws so they don’t float away or they’re smashing open a shellfish for a midday snack. Recently, sea otters have had a spike in popularity because of the viral videos featuring an orphaned sea otter pup. At Monterey Bay Aquarium, researchers helped the young otter learn some of the skills that it would need to be released back into the wild. Of course, people loved to see the adorable little bundle of fluff hesitantly learning to swim and fetch floating objects. But in the wild, sea otters are not only cute- they are also the key to maintaining the balance of their ecosystems.

Something interesting about sea otters is that they don’t have some of the distinctive traits that other marine mammals have. Unlike the other seafaring mammals, the otters don’t have an insulating layer of blubber; instead relying on their exceptionally thick fur coat (in fact, it is the densest fur of any mammal on Earth). This prevents heat loss when diving into the frigid Pacific Ocean waters, however, the air trapped by the fur also makes diving more difficult.They also have an unusually high metabolism, so they must eat around 20% of their body weight in shellfish every day. Most of the energy from all that food goes toward foraging for more food, although quick grooming is also energetically taxing. The way that the sea otter balances all this high-energy activity is by resting the way humans would in their backyard pools: after they’ve eaten, they spend a long time resting by just floating on the water. So far, the sea otter appears to have a pretty cushy job, with food just a short dive down from your resting spot.

sea otter eatingSea otters typically eat sea urchins, and because of their ravenous appetite, they can quickly and easily decimate the population of urchins in the ecosystem. The sea urchins in turn eat kelp, and if their numbers remain unchecked, they can turn a bustling kelp forest into a barren wasteland dotted with urchins. This means that the sea otter has a very important job: to maintain the kelp forest. Scientists have seen that when otters are reintroduced into a coastal region where they were once common, the community changes dramatically because of the return of the kelp forest. Before the reintroduction of sea otters, a kelp forest could be reduced to an urchin barren devoid of most kinds of life. With the return of the otters, sea urchins are promptly eaten before they have a chance to gnaw off the rooting systems of the kelp. The kelp forest supports many more kinds of sea creatures than the bare ocean floor left by the overgrazing urchins. When there is greater diversity of species, the ecosystem is more stable. It is also protected against drastic changes, such as sudden loss of a species, because there are different species that share similar jobs or functions within the ecosystem. In this way, if one of those species dies out or moves away, another can take its place so that the ecosystem can carry on as it was.

Luckily for us, the sea otters were able to bounce back from the brink of extinction. Historically, sea otters were hunted for their thick, soft furs in their native habitats off the coasts of Alaska and California. Fortunately, the natives of San Miguel found a way to coexist with them without cutting out their fur trade or overhunting the sea otters. The people still hunted the otters for their fur, but only in remote areas away from shellfish beds. These shellfish beds were protected because both sea otters and humans liked to eat red abalones. About six hundred years later, scientists are developing more sophisticated species recovery strategies based on ecosystem function. New methods for evaluating the recovery of a species that had been lost are shifting from demographics (kind of like a head count or census of the recovering population) toward more ecology-based criterion. For sea otters, this new method only requires counting sea urchins, which are far easier to count because they’re pretty sedentary. After that, the number of sea urchins is entered into an algorithm that will provide an estimate of the sea kelp coverage. A kelp-dominated area would be considered to have a fully recovered sea otter population, since they would have eaten most of the sea urchins that prevented the kelp forest from growing. Compared to the old methods of numerous aerial sweeps, this new method is both cheaper and more effective for long-lasting species recovery. In this way, the biologically diverse kelp forest ecosystem is preserved thanks to the sea otters.

Sea-otters-holding-hands_-Photo-credit-2What does this mean for humans? Well, although fisheries are competing with the otters for shellfish, the reestablished kelp forest will attract more types of fish for us to eat. Sea otters can also provide a boost in tourism in the same way that whale watches do. Tourists would love to see an adorable sea otter in the wild. They can take pictures of the otters holding hands or watch them cleverly use rocks as tools to break open a clam the same way they would at a restaurant (although with a more sophisticated tool than a rock). I’m sure the Monterey Bay Aquarium can attest to the popularity of otters with tourists, as many are probably eager to see the baby sea otter from the viral videos.

Out of the Mason Jar: Firefly Communication


It is a summer evening. The blue dark is just starting to settle beneath the trees and the fireflies are beginning their nightly ritualistic dance across my front lawn. As a kid, I would see the fireflies flashing, and I was entranced. It seemed they were beckoning me, and I would oblige, chasing them across the yard as the sunlight waned. I’m not the first person to be drawn out into the dusk with their hands flailing at these bobbing lights. I’m not the first person who misinterpreted the flashes as something to catch, like bits of magic to be stored in a mason jar and stared at for hours once I brought it back in with me. When the younger me so fervently chased, captured, and stared at fireflies, I had no idea that I was falling prey to the very same hypnosis that entranced millions of people before me. It is a phenomenon many centuries old, that children, tourists, artists, and scientists alike are drawn to firefly light.

The Light Show, Great Smoky Mountains

While poets romanticize the insect’s self-produced light, or bioluminescence, into stanzas, scientists unravel the meanings and processes behind it through data collection. Over time, scientists gathered enough data to conclude that these individual flashes are merely syllables in a conversation between males and females of specific firefly species, wherein the female lures in potential male mates with a receptive flashing signal.Therefore, firefly bioluminescence not only captures humanity’s attention, but it also captures the attention of the fireflies themselves.

Hoping for love, male fireflies dart across fields, over lawns, and through forests, using their flashing lights to woo the females hidden in the shrubbery or forest litter below them. Each species of firefly emits light at a certain tempo, a beat that the male keeps so that the female can spot him in the darkness. Then, if a female finds a male attractive enough, she will beckon him to her by flashing in doublets. Across species, females tend to prefer males with longer, more consistent flashes, though a firefly flash’s physical qualities can vary depending on which species is emitting the signal. Brightness, color, the quantity of flashes, the overall rhythm, and the duration of each flash are all characteristics that change depending on the species being observed. Therefore, males whose territories overlap with another firefly species can easily tell which females they are compatible with by glancing at their flash patterns.

A tree aglow with male fireflies flashing simultaneously

Male fireflies sometimes band together and woo their women as a team, using simultaneously timed flashes. This synchronous flashing behavior is thought to be an evolutionary step toward more efficient courtship between males and females. Since there are so many males vying for a single female signal, this poses challenges for the female. Her signal can get lost and confused in the midst of all of these flashes, multiple of the wrong suitors may respond to a signal specified for a particular male. Also, the cacophony of incoming signals is overwhelmingly difficult for the female to receive, process, and interpret. This visual onslaught is known as photic noise. This is reduced when the males flash in synchrony. While it doesn’t prevent multiple males from responding to the female flash, it allows the female to easily interpret the signal given to her by a male group. Then, the males also respond as a group, becoming rivals as they compete for the female’s attention. As they near the female, they form groups around the female. These groups are known as “love clusters.”

Sometimes, however, female fireflies temporarily adopt the flashing patterns of another firefly species. The males who are tricked into responding are killed and eaten by the female who is pretending to be a potential mate. This interaction, known as aggressive mimicry, occurs between Photuris and Photinus fireflies: two species commonly found in the Great Smoky Mountains. Some individuals from these firefly species participate in kleptoparasitism, as well. Kleptoparasitism is the act of feeding off of another species by stealing their food. Photuris fireflies do this by responding to signals of distress from Photinus fireflies that are caught in spider webs. Scientists are still unsure as to what purpose the distress flashes pose for  the trapped firefly, however, the female Photuris firefly benefits because it makes the entangled male easier to spot. The female Photuris then rescues the Photinus firefly from the silky tangles of the spider web. However, the male Photinus firefly isn’t free for long, as the Photuris firefly proceeds to prey on him.

Photinus female preying on a Photuris male

It is proven that the female fireflies play this trick to protect themselves and their larvae. This is because the Photinus firefly naturally contains a substance that the Photuris firefly can only gain by ingesting the male victim. These substances, called lucibufagins, are known to repel potential predators from fireflies and their oocytes, or eggs. Participating in this bioluminescent trickery to obtain the substance, therefore, has many beneficial repercussions for the Photuris firefly.

It seems that the various patterns of firefly flashes can contain specific meanings and intentions. The firefly’s light patterns contain meanings that accomplish more than it may seem while watching the dazzling display from one’s porch. Like morse code, the light helps fireflies communicate. Also, a specific light pattern is a firefly species’ identity and trademark.  Bioluminescence helps the firefly woo its mates, prey on its own kind, and cry for help in times of distress. There is great scientific significance beneath what can seem like simple blinks and spurts of light in the summertime darkness. Yet, every once in a while, it is easy to fall into that trance. Pressing our noses up against the mason jar’s glass like amazed children, everyone can experience the magic for a little while.


  • Eisner, T., D.F. Wiemer, L.W. Haynes, and J. Meinwald. 1978. Lucibufagins: defensive steroids from the fireflies Photinus ignites and P. marginellus (Coleoptera: Lampyridae) Proc. Natl. Acad. Sci. 75:905-908
  • Faust, L.F. 2010. Natural history and flash repertoire of the synchronous firefly Photinus carolinus(Coleoptera: Lampyridae) in the great smoky mountains national park. Florida Entomologist 93:208-217.
  • Faust, L., R. De Cock, and S. Lewis. 2012. Thieves in the night: kleptoparasitism by fireflies inthe genus Photuris dejean (Coleoptera: Lampyridae). The Coleopterists Bulletin 66:1-6
  • Lewis, S.M., and C.K. Cratsley. 2008. Flash signal evolution, mate choice, and predation in fireflies. Annu. Rev. Entomol. 53:293-321.

Siphonophores: The Specialization, Cooperation, and Integration of Zooids

Critical to the function of multicellular organisms is the specialization of cells, cooperation between cells, and a body plan to sustain integration. Yet the term multicellular organism applies to the order Siphonophorae in more ways than one. Siphonophores can be further defined as a colonial organism and perhaps the most exemplary models. Characteristic of siphonophores are multicellular components known collectively as zooids. The classification of siphonophores as both colonial and as individuals makes them one of nature’s most impressive morphological anomalies.

But what are the benefits of being a colonial organism? The answer is simple: colonialism in nature is an advantageous systematic division of labor within the colony. For example, resources are used more efficiently when active components only exert energy on a specialized task. Claims have even been made that siphonophores have the highest division of labor between zooids and most precise organization of all colonial animals.

The specialized components of siphonophores are zooids. In fact, the zooids of siphonophores are so specialized that they can be restricted to only one function, requiring obligatory cooperation and tight integration. The zooids of a siphonophore are so interdependent, allowing siphonophores to be regarded as colonial organism despite the components.

Siphonophorae is an order of carnivorous organisms which belong to the phylum Cnidaria. Each zooid of the colony is considered either a modified medusa, similar to a free-swimming jellyfish, or a polyp. Both are reminiscent of free-living cnidarians. A variety of zooids exists, functionally specialized and arranged in specific patterns. They vary in distribution across the ocean and different depths as well.

The body plan of a siphonophore is used to further classify a species into distinct suborders. There are three that belong to Siphonophorae: Physonectae, Cystonectae, and Calycophorae. To categorize an organism into a suborder, they must possess at least two out of three classifying segments. Listed respectively from the anterior end of the organism to the posterior end, the segments include a pneumatophore used for buoyancy, the nectosome responsible for locomotion, and the siphosome used for prey capture and additional zooid activity. The pneumatophore and zooids of each segment are attached along a central stalk called the stem . The only members of Siphonophorae composed of all three segments are the physonects. The body plans can be easily visualized in Fig.1 which is a representation of suborders and corresponding body plans.


Figure 1. The schematic body plans of the three siphonophore suborders.

Despite differences in the body plans, zooids retain four defining characteristics: First, they arise by budding from single protozooid. Second, it is crucial for zooids to distribute nutrients throughout the entire organism; therefore, colonies must be strongly integrated to allow the direct exchange of metabolites to occur. Third, the behavior exhibited by zooids in colonies is controlled by nerves, conducting epithelia, or both.

The final defining characteristic is one which must always be kept in mind. The term zooid has powerful evolutionary connotations. Zooids will retain individuality, despite how specialized they are, or inferior to the developing siphonophore .

Ironically, the pneumatophore of a siphonophore is not actually a zooid, and functions as a float in some cases, but is more likely to function as a sensory structure. Larger pneumatophores hold the colony upright, assisting with other zooid bearing segments which may be long and heavy.

Moving backwards, the specialized medusoid zooids of the nectosome are encountered. These are the nectophores. Nectophores are dedicated solely to the locomotion of the colony. There are no reproductive or feeding structures present. A further examination of nectophore physiology reveals that nectophore zooids grow quickly after budding. Nerves run from the stem to the nectophores, coordinating the swimming contractions.

Finally, at the posterior end of the nectosome begins the siphosome, which bears remaining specialized zooids. The siphosomal growth zone marks is the anterior portion of the siphosome and origin of the siphosomal stem, becoming longer as the colony grows. Pro-buds emerge in the siphosomal growth zone and the attached zooids are organized in a specific repeating pattern. When a cormidia is first developing it is referred to as the pro-bud. a visualization is found in Fig. 2.

Figure 2. A labelled illustration of a siphonophore and major components

Figure 2. A labelled illustration of a siphonophore and all of the major body components.

The gastrozooids are zooids that specialize in feeding. Efficient prey capture and consumption is achieved by dividing gastrozooids into two regions: the oral hypostome and the aboral basigaster. The hypostome extends furthest  with a folded mouth to consume large prey. The basigaster attaches the gastrozooid to the siphosomal stem and has a thick layer of tissue where the maturation of nematocysts occurs.

The tentacle possessed by each gastrozooid is also associated with the basigaster and attaches to the bottom. The tentacle is not  a zooid but cooperates with gastrozooids to obtain food. Extending from the tentacle are strings of tentilla tipped with nematocyst batteries. A battery contains a cnidoband filled with nematocysts and an elastic ligament.

Discharge of a battery occurs when the terminal filament of the tentilla is pulled and the spiny penetrative threads of each nematocyst are released into the prey. As the prey struggles it is continuously pierced until the tentacle has contracted enough for consumption by the associated gastrozooid.

In addition to the gastrozooids, are palpons. They are attached to the siphosomal stem, possessing a single palpacle, similar to a tentacle. At the base of the palpon is a region for developing nematocysts which develop in stages like those of gastrozooid. No sensory cells near the tip mean it cannot function as a sensory zooid but it is also thought that they participate as digestion modules despite an inability to feed.

Siphonophores also have a few tricks to lure prey toward themselves. Aggressive mimicry is exhibited when the nematocyst batteries of the siphonophore act as bait by looking similar to copepods or fish larvae. Bioluminescence in marine environments is rare but siphonophores belonging to the genus Erenna have been observed demonstrating the flickering of tentilla. These events may have appeared as prey behavior to small predators which would attract them toward the lures.

Once the ingestion and digestion zooid functions are completed, nutrients must then be transported to the other regions of the colony, sometimes over distances of centimeters or meters. Digested food matter in the stem canal flushing up and down the stem by rhythmic movements of the gastrozooids and palpons . Cilia  assist the process of nutrient distribution and valves at the bases of the zooids allow the exchange of fluids with the stem.

Aside from the digestive zooids of the siphosome are the sexual zooids called gonodendra. Each is directly attached to the stem and bears multiple gonophores thought to be greatly reduced medusae. The gonophores of male gonodendrons contain large populations of beginner cells. Female gonodendrons are connected to gonophores which each contain a single oocyte. The protozooid eventually buds off of the gonophores. The stem elongates and buds from two blastogenic zones, otherwise known as the nectosomal and siphosomal growth zones in Fig. 2 begin to mature.

From ornate and colorful to transparent and shapeless, the organization and complexity of siphonophores cannot be paralleled. The homology between free swimming organisms and the zooids  establishes that there must clearly be an advantage to such extreme  integration. The specialization and coordination between zooids to form a single colonial organism is profound and will always challenge the term ‘individual’ which is certainly worth time for contemplation.

The Possibilities of De-extinction

Every year, more and more species of plants and animals are declared extinct— meaning that there are no living members of the species left. In the past, extinction was brought on by various natural reasons, including gradual changes in climate and natural disasters such as volcanoes, floods, and fires. Now, the biggest factor causing species to go extinct is the influence of humanity. Humans are causing extinctions to happen at the fastest rate in history, through destruction of habit as well as influence on global temperatures. So what can we do to fix it? The first steps are in the conservation of remaining habitats and species, changing the way we interact with our environment. Soon it may be possible to go even farther than conserving current wildlife; soon, we may be able to bring back those species that are already gone.

De-extinction is the general name for processes of bringing back species that have gone extinct. There are multiple methods to achieve this goal. Here I will explore three such methods: cloning, genome modification, and selective breeding.

The idea of cloning an animal is one that’s very popular and often sensationalized by the media. But how does it really work? Cloning starts by extracting the DNA-containing nucleus from a cell belonging to the animal to be cloned. This nucleus is then inserted into an enucleated (deprived of its nucleus) egg cell which, in the case of mammals, is transferred into a surrogate mother of the donor species once it starts to divide and grow. Once born, the clone is a genetic twin to the original donor of DNA; however, this includes such drawbacks as telomere shortening (genetic aging). This has successfully been done many times over the years. The first such clone of a living animal was Dolly the sheep in 1997. A group of scientists in Edinburgh, Scotland took the nucleus of a cell from an adult sheep and transferred it to the egg cell of another sheep. Their success was the first evidence that a clone could be made using an adult cell. Since then, many different species of living animals have been cloned, including the endangered Indian bison.

The next step towards de-extinction via cloning is to clone one that is no longer living. The first progress made towards the reincarnation of an extinct species occurred in 2009. Spanish researchers took frozen tissue from a recently extinct species of wild goat, Capra pyrenaica pyrenaica, which had been frozen for just this reason. They inserted its genetic material into a closely related species to act as surrogate mother, since there were (obviously) no members of the original goat species remaining. The result was the birth of a living C. pyrenaica, although it only survived for a few minutes past birth due to respiratory defects.

Despite the results of these experiments, there is still an issue that needs to be addressed before we can truly bring back any extinct species. In the case of C. pyrenaica, there was tissue frozen preserved in advance for use in the cloning process. With most extinct species, especially long extinct ones, this is not the case. How do we solve that problem? There are a couple of ways.

The first is by extracting DNA from fossils. Now, most of the time this isn’t plausible. Once an organism is no longer living, DNA breaks down at a fairly fast rate. There is research that has been done measuring these rates, which tells us that the half-life of DNA is a little over 500 years in fossilized tissues. This means that in 500 years, half of a DNA sample will have degraded. The result of this is that any animal which went extinct over 500 years ago is usually not going to be something we can bring back just by using cloning methods. That being said, there is an exception found in one famous extinct animal: the woolly mammoth. Woolly mammoths lived in the cold arctic northern regions of North America, where they were hunted to extinction by early humans. Because many fossilized remains were frozen in ice, its DNA did not degrade completely and could potentially be pieced together; this is currently a work in progress. For any species that are nearing extinction, a frozen sample of tissue can also be collected, like in the case of our Spanish goat, so that it can later be cloned back into existence.

Another solution for filling in missing DNA is through a process called genome modification. This involves taking a close relative to the extinct species, which has a very similar sequence of DNA (relatively speaking). If most of the genome of the extinct species can be pieced together using fragments of DNA collected from preserved tissues, a close enough relative could be used to fill in the holes. From here, the same process as cloning would be used to turn this DNA into a living animal: it would be inserted into the egg cell of its closest living relative. An example of this being done in science is in the recently extinct passenger pigeon, whose partial DNA is accessible from toe pad tissues of preserved specimens. This species was killed off entirely by humans, but has close living relatives such as the carrier pigeon which may help us pieces together its lost blueprint.

The final method I’m going to talk about is a little less sci-fi than cloning and genome modification: selective breeding. If you have a pet dog, you have seen the effects of selective breeding done by humans. It is the process of selecting desirable traits in individuals of a species, and breeding those individuals together to carry on the desired traits. This method only applies to species with a descendent that is still living. In the context of de-extinction, a domestic species would be taken, and bred to select traits that were found in its wild ancestors. This, after many generations, would produce an animal that is able to survive on its own as the ancestral species once did. Such“breeding back” has already been accomplished to a small extent: there is a population of cows known as Heck cattle that were bred in the 1940’s to resemble their wild ancestor, the auroch. This population is now living completely independent of humans in a wildlife preserve in Europe, representing the first species of bovine to live in the wild in Europe in centuries.

Whether or not humans “owe it” to the species that we have caused to become extinct, or whether it is just a novelty that will never be widespread, the concept of being able to bring back a lost species is a fascinating one. And now, with methods such as the ones described above, this fascinating and incredible concept may become a reality in the future.