BioQuakes

AP Biology class blog for discussing current research in Biology

Author: punhuttsquare

Avenging Lamarck: The Epigenetics of a Fish

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On April 5, 2017

In Student Post

The laughingstock of biology classrooms everywhere, the footnote to Charles Darwin and his widely acclaimed theory of natural selection, the scientist who has caused many a biology student to stop and wonder why he or she should even know his name, Jean Baptiste Lamarck has gotten a bad rap among student’s across the country. Predicting that evolution in species resulted from individual species adapting to their environment and morphing their bodies to better survive and reproduce, passing their adapted traits to their offspring, Lamarck has been criticized by students everywhere for simply not being correct. However, he wasn’t entirely wrong. Recent research conducted in the Gulf of St. Lawerence off the Labrador Peninsula has revealed that skate fish  in the area have developed differences in terms of size from other skate fish because individual organisms are able to turn on and off select genes.

https://en.wikipedia.org/wiki/Mottled_skate

The ability to turn on and off certain genes in organisms based on environmental conditions and pass those changes to offspring is called epigenetics. Epigenetics allows individual organisms to change their traits slightly to adapt to their environment. Where evolution by natural selection takes millions of years and results in the evolution of populations on a macro scale rather than individual organisms, epigenetic changes are much quicker.

Researchers were attracted to studying the winter skate fish in this bay because though the fish lies all along the North American coast, in this bay, the fish tends to be significantly smaller than other members of its species. Scientists attribute this to the warm water in this shallow water area which makes smaller organisms more likely to survive and reproduce.

However, DNA tests showed that significant changes in the genome of the fish weren’t what made them smaller, indicating it wasn’t Darwinian natural selection that dominated this process. The researchers discovered that the fish could turn on and off certain pieces of DNA in individual organisms to better adapt to the environment. Thus, the fish are able to adapt more quickly to changes in temperature than other organisms that rely solely on natural selection for changes to their traits.

Thus, Lamarck wasn’t entirely wrong all along (just mostly!).

The researchers hope this new information will help with conservation efforts and will give more insight into how species adapt to climate change.

So, do we owe Lamarck an apology? How can conservationists use this information to draw more interest to their goal?

A Snap Shot of A Frog’s Slap Shot

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On March 1, 2017

In Student Post

Mix some water and cornstarch. We’ve all made it in science class: Oobleck! It’s that weird solid-ish liquidy substance that feels like wet putty in your hands. And it has more in common with a frog’s saliva than you think (partially because it’s a little odd if you’re constantly thinking about frog saliva, but you should be because it’s really cool!!!).

A Ph.D. student Alexis C. Noel and her supervisor David L. Hu at Georgia Tech studied and published their findings in Royal Society Interface. on how, by the laws of physics, a frog’s tongue catches its prey.

The duo was engaged in some hardcore, in-depth, scholarly research scavanging Youtube for the most ground breaking viral videos of the century when they had a spark of inspiration coming from an unlikely source: a video of a frog destroying all our high scores at a game of Ant Smasher with its long tongue (see this is why all homework should be to watch Youtube videos).

https://www.flickr.com/photos/davemedia/9691234326

These two individuals became curious just how a frog’s quick and sticky tongue physically was able to catch its prey. They first had to find a high-speed camera, which they used at the Atlanta Botanical Garden and Zoo Atlanta, to record frog tongues in motion since the whole event takes place in the blink of an eye. They also tested saliva and tongue tissue samples and with data on the speed of the tongue and the viscosity of frogs’ saliva, developed a computer simulation to test their hypotheses.

Their results were as follows: frog saliva just like oobleck is a non-Newtonian Fluid!

Non-Newtonian fluids change their viscosity depending on the speed (shear rate) at which the liquid flows. Oobleck is a non-Newtonian fluid because when it is undisturbed it acts more like a liquid but if you squeeze it with a fist, it behaves more like a solid.

Frog saliva, which is usually 50,000 times stickier than that of humans, initially behaves less like a liquid. However, the force of the impact between the frog’s tongue and its prey is so great it causes the saliva to liquify more. Thus, the saliva gets into every crevice and covers the insect. When the saliva re-solidifies, the frog has a strong grip on the insect so it can reel it back in.

Of course, there is just one more issue. The frog now needs to release the insect from its tongue so that it can swallow it. To do so, it violently sucks in its eyes, creating a huge force that once again liquifies the saliva, releasing the insect.

So, there you go! That’s the secret to a frog’s saliva. But after reading this you might be thinking: that’s such a random thing to research! Well, the researchers note that this mechanism could be replicated in the development of robots made out of soft materials, a large technology field developing. They believe that this technology could help the robots made out of light and more flexible materials better grip items.

What other technologies do you think this research could aid?

Parents Take Warning: Antibiotics Can Be Harmful to Infants

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On January 18, 2017

In Student Post

Antibiotics are the marvel of modern medicine. They have brought about incredible medical advances, treating bacterial diseases and helping to prolong lifespans in modern times. But a new study conducted by researchers at the Massachusetts General Hospital and the Broad Institute has shined a light on the potential negative effects antibiotics can have on an infant’s health.

https://www.flickr.com/photos/herebedragons/2573487530

The study, conducted in partnership with a team of Finnish researchers, took monthly fecal samples from 39 children from birth until they were 36 months old and analyzed the sample using standard, RNA sequencing procedure to identify different microbes. During the study, 20 of the children had taken antibiotics for respiratory or ear infections ranging from 9 to 15 treatments over the course of the study. From this data, the researchers could analyze the diversity of the gut microbiome of these participants with respect to their antibiotic usage.

The researchers had chosen to analyze the effect antibiotics have on the gut microbiome in young children because of the pivotal role antibiotics appear to play in human health during early development. Low diversity in the early years of life of this collection of bacteria residing in the intestines has been linked to allergies and autoimmune diseases.

The results of this study show a decrease in the diversity of the microbial gut populations in infants who took antibiotics. This was even more pronounced when the infants were marked with a specific signature low in a bacteria known as Bacteriodes (this decrease in Bacteriodes has been speculated to be linked to Caesarean section births in the past but the researchers found this rationale to be inconclusive as well as another rationale that prolonged breastfeeding led to a stronger gut microbiome with higher levels of Bifidobacteria).

When the infants had taken antibiotics, a single strain of bacteria tended to rule their gut with only a few species surviving. On the whole, the gut microbiomes of these participants were less stable and had higher levels of antibiotic resistant genes.

Don’t get me wrong: antibiotics are an incredible innovation that has saved millions of lives. But, be careful in thinking they are a cure all. They’re side-effects might be more harmful than you think, especially in children.

How does this research change your perception of antibiotics?

 

Meet Charlotte’s Cousin (She’s Coming to the Web this Year for Thanksgiving)

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On November 21, 2016

In Student Post

You’re taking a nice autumn walk, enjoying the scenic pathway covered in red, yellow, and brown beautiful leaves. You stop at tree and notice one small, shriveled up decaying leaf still hanging. In a whimsical motion, you decide to pluck the final leaf… Aaaaaahhhh! Spider!

Folks, you’ve heard of the stick bug. Let me introduce you to the leaf spider (it has yet to be officially named!). Don’t worry, you’re unlikely to find one unless you’re in China.

The Leaf Spider’s Cousin: The Barn Spider                                      Credit: https://www.flickr.com/photos/tmh9/233350520

On a research excursion in Yunnan, China in 2011 (they published their findings on November 11), researcher Matjaz Kuntner* and his team came across an unusual species unidentified by the likes of man, the only known spider to resemble a dried up leaf!

Camouflage isn’t new in the animal kingdom; it’s a popular survival trait. But its more common with insects like the stick bug than arachnids.

However, roughly 100 species of spiders have bodies that don’t resemble your typical halloween decoration, ranging from a jumble of twigs to bird poo. But nothing like this!

They described the spider’s back as looking like a healthy green life while its underside resembled a dead brown leaf. And a hairy, stalk like structure branches out of its abdomen like the stem of a leaf! Take a look for yourself!

After searching for another specimen for two weeks, the researchers found only one more: a juvenile male. Searching the world’s museum for another sample, only one resembling the new specimen could be found (in a museum in Vietnam) but it is suspected this specimen comes from a known species whereas these two new individuals are a brand new discovery!

But the icing on the cake… as the title suggests, this spider is a cousin of Charlotte from Charlotte’s Web! Yes, the barn spider (Araneus cavaticus) and this new spider both belong to the Poltys genus along with 3,000 relatives (what a family reunion!).

One thing to note: the researchers noticed leaves stuck to the branch the spider was resting on by silk, indicating that the spider might have placed the leaves there on purpose. Keep an eye out for new research on the matter in the future.

So, the pivotal question I ask anyone who reads this… what should the spider be called? Do you know of any cool arachnids or insects that use camouflage in unique ways? Let me know in the comments.

Original Article: http://www.livescience.com/56910-leaf-mimicking-spider-found.html

 

*Matjaz Kuntner is a principal investigator with the Evolutionary Zoology Lab at the Biological Institute Jovan Hadzi, Scientific Research Centre of the Slovenian Academy of Sciences and Arts.

How Did Our Baby Learn That Word?!?!

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On October 12, 2016

In Student Post

Jason Sudeikis’ character is hosting a nice dinner party with his wife played by Jennifer Aniston, and all seems to be going great. Then, all of a sudden, their 12- month-old baby blurts out a curse word! “How could our baby learn such a thing?” In a flashback 8 months earlier, we see the less-experienced parenting pair blurt out some pretty R-rated things in a fit of frustration on the road with their baby in the backseat. And so the punch line sinks in.

In modern day parenting comedies, scenes like this fabricated one are a dime a dozen. But these humorous takes on life always get at least one thing right: babies are sponges. Let’s take a look at why on a cellular level.

image source: https://commons.wikimedia.org/wiki/File%3AComplete_neuron_cell_diagram_en.svg

Prior to birth, most neurons migrate to the frontal lobe of the brain where, during postnatal development, they link together and forge connections, allowing a baby to learn proper responses to stimuli. The “circuits” formed by the neural connections are incredibly flexible during the early months of development (roughly the first 6 months) and can quickly be formed or severed, resulting in a remarkable neonatal human ability to rapidly pick up new knowledge about our surroundings. But how are they so malleable?!

Researchers at the University of California, San Francisco may have the answer! In a study coauthored by neuropathologist Eric Huang, they found neurons forming a chain moving towards the frontal lobe from the sub ventricular zone, a layer inside the brain where nerve cells are formed, in infants up to 7 months old!

This research seems to point to the idea that these new brain cells form connections with the pre-existing neurons in the frontal lobe later in the infant’s development, resulting in more cognitive flexibility for a longer period of time.

To quote the original article by Laurel Hamers, what the new neurons are doing is analogous to “replenishing the frontal lobe’s supply of building blocks midway through construction”.

Huang’s team observed postmortem infant brain tissue under an electron microscope and discovered a group of neurons synthesizing migration proteins, but the real major discovery came with the observation of rare tissue acquired moments after death. The team injected viruses tagged with glowing proteins into the neurons (thus making the nerve cells glow) in the sample and tracked their movement. While infants up to 7 months old were observed with migrating neurons, the researchers recorded the number of migrating cells at its highest at 1.5 months old and saw it diminish thereafter. The migrating neurons usually become inhibitory interneurons which, to quote the original article, are “like stoplights for other neurons, keeping signaling in check”.

So there you have it! To make sure your baby doesn’t learn that bad word, just suck up all the migrating neurons from its brain!

All jokes aside, this research presents an amazing window into the brain development of the most intelligent species on earth! It’s fascinating how it breaks down psychological mysteries using cellular evidence. And it raises new questions about these mobile neurons: When are they created and how long does it take them to move to the frontal lobe?

How do you think this new research will influence our understanding of the creation of social biases? Do you think this will lead to breakthroughs in research on the foundation of Autism spectrum disorders?  Do you have any funny baby stories? Let me know in the comments.

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