AP Biology class blog for discussing current research in Biology

Author: carolenzyme

Sperm Epigenetics and the Next Generation

Jerome Jullien from the Welcome Trust CRUK Gurdon Institute in Cambridge experimented with frogs to see if more than just DNA is passed on to the second generation offspring.  Sperm contain something called epigenetic tags which are “chemical switches attached to the genomes of sperm.”  (It is important to understand that epigenetics does not alter an organism’s DNA.)  In order to test if these sperm epigenetics influence offspring Jullien used two types of sperm; regular frog sperm and spermatids which had different epigenetic tags.  They then injected the sperm and spermatid into genetically engineered eggs which took away some of the epigenetic tags (with specific enzymes) on the sperm.  This lead to abnormal gene expression causing problems for the offspring.

This basically shows that a male does not simply pass down his DNA to his offspring but other factors like epigenetic tags can also effect the life of their kids.  As Jullien says, “The obvious implication is that whatever experiences the father has in life that end up epigentically modifying sperm cells might also be transmitted to the offspring and affect their genetic development and characteristics.”  There is still disagreement over whether epigenetic tags on sperm influence offspring.  For example some feel the experiment tested was not realistic because the frogs were not exposed to different environments as a human would be in his lifetime.  What do you think; would epigenetic tags on male sperm have an effect on a mans offspring?

New Research Shows Possible Early Diagnosis of Autism

Normally autism in children is diagnosed at around ages two or three but studies have been done to try to predict autism before behavioral symptoms occur.  University of North Carolina partnered with other universities to experiment with MRI machines to see if they could diagnose autism earlier than 24 months (2 years)

Autism is a big problem in our country and the rest of the world.  About 3 million people have autism in the United States and millions more throughout the world.  The study focused on hyper-expansion of brain surface area in children of 6-12 months of age. According to this article “Brain overgrowth was tied to the emergence of autistic social deficits in the second year.” They found that 8 out of 10 kids with a hyper-expanded brain as well as an autistic sibling would be diagnosed with autism in the future.

The fact that MRI’s can show enlarged surface area of the brain at such a young age is important in predicting whether or not a child will be later diagnosed with autism.  This is an important experiment because if doctors can predict autism before symptoms occur there may be ways for them to intervene with brain growth before a child’s brain permanently has autism and behavioral changes occur at 24 months.



When in doubt go with your gut!

The human gut has trillions of bacteria that help to regulate digestion and break down food.  An extremely important function they have is to keep out bad bacteria and potential harmful microbes.  The gut is a very important part of the body, because it affects not only your digestion and metabolism, but your brain too!

Often called your “second brain,” the human gut plays a big role in a human’s life.  The gut produces about 95% of serotonin, which is the drug that affects emotion.  An experiment with mice was done to see the effect that their gut had on their brain activity.

Each mouse received antibiotics, consisting of neurochemicals that enhanced mood, and were observed after this change occurred in their gut.  The mice became more energetic.  The article mentioned that even changing an animal’s gut by one bacteria can change their mood.  In this case altering one bacteria was tested which caused the mice to be more cautious than normal.

This article went in depth on how the bacteria in your gut can cause anxiety. “Bacteria communicate with the brain via the vagus nerve: When the vagus nerve is severed, effects of gut bacteria on brain biochemistry, stress response and behavior evaporate.”  They then went on to discuss how someone’s brain can affect the human gut, which was extremely fascinating.

Golden Snub-nosed Monkeys, Qinling Mountains - China

They first did tests with monkey’s and found that mothers who were exposed to loud noises during pregnancy caused their offspring to have less beneficial bacteria.  Another experiment was done with students in which they gave stool samples during exam week.  The results showed that their was less good bacteria in their gut, called lactobacilli.

In general the human gut plays a huge role on the brain and vice versa.  Stay healthy, don’t stress too much over school because you never know what anxiety could be doing to the good bacteria in your gut!

I chose this article because I have stomach issues and had to go gluten free.  I didn’t realize what goes into your gut had such a large effect on the brain!


Would you eat food made from natural gas?

Methane Gas

Every since we were little we have been told that plants are a source of food and energy created by photosynthesis.  Humans eat plants and we eat animals that eat plants.  This is how energy is passed on, but what if I told you there was a way to get energy not from plants but from gas?  Seems kind of gross, right?

Michael Le Page wrote an article on the biotechnology company, Calysta, that has been working to use natural gas as forms of food for different animals.   They experiment with creating feed for farmed fish.  The process of creating this feed requires microbes that are put in a big area with methane.  Microbes feed off the methane and convert the digested methane into energy.  At the biotechnology company they specifically used a type of bacteria called Methlyococcus capsulatus which feeds off of the methane.  This process releases energy that can then be combined with other molecules to create food.  What is the point of this process?

This process of creating energy and food in a different way compared to photosynthesis has both positive and negative effects.  The reason for preforming such a strategy is to decrease a demand for land use (for example all of the farms used to grow plants and other crops), and to lower the amount of water used.  Another positive is the way in which methane is being used to create this feed.  Normally, in order to rid of methane it is just burned, but the way in which it is used for microbes to feed on it is much more productive and less wasteful.  Methane is a green house gas and is bad for the environment.  Instead of just burning it these studies have shown that it can be a useful source of food.  On the negative side using methane gas to produce energy results in the emission a lot of CO2.  CO2 is a also a greenhouse gas that increases the earths temperature, and adds to the problem of global warming.

Fish Farm

This process of creating feed when microbes convert methane to food has been pretty successful; some farm animals are eating this feed.  You never know, maybe one day humans will be eating food made from natural gases.  It really depends on where the world puts its priorities due to both negative and positive outcomes of the process.  What do you think is our most important priority?  Should factories go ahead and make this feed, despite the high levels of CO2 released?



Don’t BEE Hating on BEES (Bees and Emotion)

Have you ever stepped on a bee or crushed it out of anger because it was bothering you?  Little did you probably realize that there is scientific evidence that bees, do in fact, experience emotion.  Biologist Clint Perry, University of London demonstrated this phenomenon in his bee experiment.  In order to see if bees really did experience emotion he ran a test with a blue flower and a green flower.  The blue flower had a 30 percent sugar solution, ultimately causing the bees to associate blue flowers with a sweet treat.

After this he created another experiment in which 50% of his bees were given sugar water and the other half were not.  He set up colored flowers and in his experiment found that the bees given a 60% sugar water solution to drink flew more quickly to the flower they were trained to go to (in this case the blue one), compared to the bees that were not given sugar water.  This sugar seemed to have “amped up the bees into a positive emotional state, making them more optimistic that the flower would contain a sugary treat.”  The author of this article compared this to humans and how after eating a sweat treat are in a better emotional state and feel happy.  Another experiment done was with a drug that disrupted receptors of dopamine, causing the preference and motivation to disappear.  This proves the importance of the chemical dopamine in the brain.  Dopamine is ultimately what is giving the bees emotion.  It is important to understand that biologist Clint Perry did not prove that bees have feelings, because feelings are different than emotion. “Emotions are the body’s adaptive response to external events or stimuli.  Feelings are subjective to experience of them.”  In this experiment emotions were tested because it tested the bees response to something rather than past experience.

Now that we know bees have emotion is it possible that eventually they may acquire feelings?  Maybe you will think twice the next time you swat a bee away!

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