BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Rats

Pythons to Blame for Increase in Dangerous Mosquitoes in Florida

The Invasion of Burmese Pythons in Southern Florida has been well documented over the last few years, and as they increase in number in the Everglades, numbers of many mammals have diminished. The addition of an extra top predator such as the Burmese Python, the second largest snake in the world, growing up to about 19 (19!!!) feet long, has dire implications for the ecosystem of the Everglades and of Florida, but they pose a danger to the humans in the area as well!

That’s right, the Burmese Pythons are causing problems for Floridians. No, Floridians are not soon-to-be victims of a Python takeover, but the disruption of the Everglade ecosystem has begun to become apparent. As Burmese Pythons have lowered numbers of countless different mammals across the Everglades, mosquitoes have less variety among the animals they drink the blood from, per ScienceDaily. As a result, Mosquitoes have been taking more blood from the mammals that remain, most notably the hispid cotton rat. Mosquitoes in the area are now taking more than 75 percent of their meals from this rat, which is a massive 422 percent increase since 1979. Burmese Pythons were first reported in the area in the 1980s. The hispid cotton rat, which so many mosquitoes feed on now, hosts the Everglades Virus, which is transferred to humans by mosquitoes. As if we didn’t have enough reasons to hate mosquitoes. The hispid cotton rat is one of the only hosts for the virus, which causes “fever, headache and even encephalitis” in humans, according to the same ScienceDaily Article.Sigmodon hispidus1.jpg

This new research is not only  relevant because of the increased hatred we all now have for mosquitoes, though. It also represents a landmark in research on invasive species. Nathan Burkett-Cadena informs ScienceDaily that “As far as I am aware, this is the first time that researchers have found that an invasive predator (such as the python) has caused an increase in contact between mosquitoes and hosts of a human pathogen.”

So, python invasions lead to more virus-carrying mosquitoes in the Everglades. Does this make you as uncomfortable as it makes me? Let me know what you think, leave a comment. I for one am glad to be far away from both the pythons and the Everglade mosquitoes.

 

Photos:

James Gathany for CDC https://commons.wikimedia.org/wiki/File:Sigmodon_hispidus1.jpg

Susan Jewell for USFWShttps://en.wikipedia.org/wiki/Burmese_pythons_in_Florida#/media/File:Burmese_python_(6887388927).jpg

 

Are Rats Ticklish?

Up until now, ticklishness has been a mysterious physical sensation.  Michael Brecht, professor at the Humboldt University of Berlin and Animal Physiologist, headed a research project along with Shimpei Ishiyama to help understand the sensation of tickling. Many questions have been asked about this mysterious physical sensation for many years without sparking answers. Even Aristotle and Charles Darwin were curious about tickling. Why are certain body part more ticklish than other? Why does the body react with smiles and laughter? Why can you not tickle yourself? Can other animals be ticklish as well?

Tickle Tickle

This image was originally posted to Flickr by Yogi at http://flickr.com/photos/34427468531@N01/113215143

Turns out, rats are ticklish too! (Click HERE for video!) In the Study, Brecht and Ishiyama, tickled the rats.  The subjects responded really well to the researchers tickling them, emitting “laughter-calls” and playfully chasing the the researcher’s hand.  The calls are ultrasonic and can not be heard by the naked human ear.  According to their laughter calls and the “unsolicited joy jumps” after being tickled, the rats are most ticklish on their bellies and on the bottom of their feet.  Brecht observes, “It’s remarkable the similarities between rats and humans – the fact they vocalise and clearly enjoy tickling so much.”  

images

British Pest Control Association

To further the research, Brecht and Ishiyama studied the brain to see what area of the brain reacts to tickling.  Cells are activated in the somatosensory cortex of the brain causing the rats to giggle.  The somatosensory cortex is part of the brain that registers touch and Brecht remarks that “we managed to pinpoint the ticklish spot in the brain.” During this study, they were able to discover that rats ticklishness is dependent on their mood.  Rats response to being tickled was far less measurable when the rats were stressed  This finding could lead to very important future research on the brain because there has been little research about how moods affects the brain.  

brain

Jkwchui

Trust Your Gut and Exercise

 

File:Wild garden of the gut bacteria 5.jpg

According to an article on GEN news, the level of Microbiomes contained within the Gut is influenced by exercise as a young child. Microbiota are the organisms that share our body space, and the gut has a particularly concentrated region of these organisms. Scientists estimate that gut microbiomes make up anywhere from 1-3% of total body mass. As it turns out the saying, “trust your gut” has some scientific merit. Microbiomes promote healthy brain function and promote anti-depressant effects, as well as adding up to 5 million genes to the human genome. Having a healthy gut is a key to overall biological health.

A recent study by Colorado University claims a connection between early life exercise and healthy microbiome activity. This study was conducted with rats, with one group young of rats exercising daily contrasted against a control of rats who behaved normally. The younger exercising rats experienced a growth of probiotic bacteria in their guts, more so then the stationary rats or even older rats who exercised. Researchers “emphasize the ability of exercise” to promote a healthy brain and metabolic function. In the future, Colorado University will look for ways to promote healthy microbiome activity in adults who have a much more stagnant microbiome structure.

 

Sources:

1.http://www.genengnews.com/gen-news-highlights/gut-microbiome-influenced-by-early-life-exercise/81252160/

2.http://learn.genetics.utah.edu/content/microbiome/

3.http://patient.info/health/the-gut

 

Fossils of Massive Rats Found

Attention fellow biology lovers: it appears our biggest fears have been realized. In East Timor, in Southeast Asia, researchers have found fossils of rats up to ten times larger than modern rats. Fear not, however, as these rats are long gone. Researcher Dr. Julien Louys said that the rats lived tens of thousands of years ago, and that there is evidence of humans actually using them as a source of food. Many of the fossils were found with cut and burn marks. The findings came as a part of a project called From Sunda to Sahul. The purpose of the project team that found the rat fossils was to find when humans started moving through Southeast Asia.

Dr. Louys believes that the rats actually lived in Southeast Asia until about one thousand years ago. He cited their extinction as being cause by the introduction of metal tools into society in Southeast Asia, enabling the inhabitants to destroy forests faster and more completely. The team is working to find the impact of humans on the Southeast Asian Ecosystem, which is directly correlated to the rats. Once they find the exact conditions that existed in the area before the rats extinction, they will have a more exact idea of what happened that left the rats extinct.

The rats themselves are characterized as mega-fauna. Mega-fauna is a term that refers to animals that are abnormally large, and these rats fall under this category. The rats are part of a movement that has seen a mass extinction of mega-fauna animals across the globe. Although the most common explanation for this unfortunate trend is human influence- which undoubtedly played a role- the reality is that hard evidence points to climate change as having a larger impact. As more research takes place, it will become clearer as to the exact reason for extinction of these massive rats in Southeast Asia. What do you think caused the extinction? Feel free to comment!

A sketch of a Deinotherium, a mega-fauna species that went extinct about 12,000 years ago. Image from Wikipedia Commons.

 

 

Can Stress Affect Pregnancies in Later Generations?

We all know stress isn’t always a good thing, but it could be important to especially avoid it at certain points in one’s life. Recently researchers from the University of Lethbridge in Canada investigated the effects of stress on pregnancies and how it can influence pre-term births. It is already known that pre-term births them selves lead to health issues later in life, but there were some new discoveries involving epigenetics.

 

Epigenetic_mechanisms

 

These researchers studied the length pregnancies of rats, due to the generally small amounts of variation between them, and found something intriguing. They carried out the experiment by first splitting the first generation of rats into “stressed” and “not stressed” groups. What they found was that the daughters of stressed rats had a shorter pregnancy than the daughters of not stressed rats.

This trend continued into the granddaughters of the rats. They also displayed high levels of glucose than the control group, and they weighed less. The stress also compounded, or increased, through generations.

This can all translate into human pregnancies. The researchers believe that the epigenetic changes in the rats is due to microRNA (miRNA) – non-coding RNA molecules that play a role in regulating gene expression. They bind to complementary mRNAs and prevent them from being translated. This is different than what is usual belief with epigenetics which is that epigenomes are affected by DNA methylation of the nucleotide base pairs. Metz, a scientist working on this research states that microRNAs “are important biomarkers of human disease, can be generated by experiences and inherited across generations. We have now shown that maternal stress can generate miRNA modifications with effects across several generations.”

It is very similar to the information found with the generational epigenetic effects of famine in the “Ghost in Our Genes” video that we watched in class.

This research can help determine pre-term births and the causalities that can come along with them. While the research is still not the whole picture, it is another step towards understanding our genetics.

 

Caffeine- helpful or harmful?

CC licensed photo by Manny Hernandez

As we all know, the highly addictive drug, caffeine, found in our coffee, tea, soda, etc… simulates us. Many people use caffeine to stay a wake which works really well. But it also causes a build up of fatty acid in the blood, raises blood pressure,  stimulates the heart, respiratory system, and central nervous system, causes stomach to produce more acid, harder to digest food because muscles surrounding the intestinal system relax, increased urination, and many other symptoms.

Is caffeine more helpful or more harmful? And where does caffeine really affect our body?

Recently, scientist have been testing caffeine on lab rats to figure out which part of the brain caffeine stimulates the most. In the first trial, they gave the rats more caffeine than what a human would normally ingest. They then decided to use  smaller amounts of caffeine which affected the hippocampus. The hippocampus is part of the brain which allows for long term memory and spacial navigation. In humans, the hippocampus is located inside the medial temporal lobe. Damage to the hippocampus may cause oxygen starvation and/or amnesia. The rats received caffeine equivalent to two human cups of coffee which is two milligrams per kilogram of body weight. The scientists measured the nerve cell’s electrical messages but examining different parts of brain tissue.

The region that had the most response to the caffeine was called CA2. CA2 showed a burst of electrical energy, while other brain regions in the hippocampus showed no sign of stimulation. The then tested the rats giving a greater dosage which caused an even greater stimulation to CA2. After that the scientists directly injected caffeine into nerve cells in a dish and the results were the same as before. About 5 minutes of caffeine intake allowed for the synapses to stay amped for three hours.

The scientists believe that when humans use caffeine the same area, CA2, will be stimulated and may strengthen a persons ability to learn and memorize, but this is just a hypothesis since they only tested on rats. So you decide… is it helpful or harmful?

Powered by WordPress & Theme by Anders Norén

Skip to toolbar