Who (Or What) Is In Charge Of Our Food Cravings?

Has anyone ever tried to trick you by asking “What is the most populous cell in the human body?” More than likely, the person asking this was a young child, as they always seem to find quirky questions like these the funniest. After digging into the back of your brain for something that you probably learned in elementary school, you may come up with a very reasonable answer: red blood cells. However, this answer to the child’s joke would be wrong. The child cleverly answers back “Actually, they aren’t cells made by the human body at all! They are the bacterial cells that inhabit our guts!”

bacteria

True, the bacteria that reside in our intestines are on the order of 100-fold greater in numbers than any other cell in the body. This begs the question of if they have any influence over the workings of our bodies. We know that the bacterial cells are important to our digestion and live in a symbiotic relationship with ourselves. Recent studies are showing that the bacteria also play a role in our appetites and our cravings. How can such tiny organisms have such great influence?

Scientists have only recently begun to appreciate the magnitude of the bacteria in our gut and the interplay between us and them. Because our digestive tract is intimately connected with our bloodstream and our lymphatic system, it is possible that bacteria release chemical signals that can travel to our brains and influence the types of foods that we next choose to eat. Bacteria are also known to produce toxins after certain foods are eaten that cause us to feel ill. This will definitely influence our choices in the future! Even more interesting is research involving the vagus nerve. This is the 10th cranial nerve that enervates the stomach, providing a direct connection between the digestive tract and the brain. Scientists believe that bacteria can produce chemicals that act upon the brain through this conduit, too!

The composition of the bacteria in our guts differ based on the foods that we eat. Some digest sugars more readily while others prefer fats. Some are even as specific as to digest cultural delicacies that are only found in certain parts of the world (and therefore, only the guts of those living in those regions). As our diets change, so do the bacteria in our intestines. Future endeavors for scientists will be to investigate changing diets and the incorporation of probiotics to alter the bacterial flora. Will this cause cravings to change? Only time will tell.

Article Source: University of California, San Francisco (UCSF). “Do gut bacteria rule our minds? In an ecosystem within us, microbes evolved to sway food choices.” ScienceDaily. ScienceDaily, 15 August 2014.

Image Source: PNNL. “Improving Human Intestinal Health” 26 September 2012 via Flickr. Creative Commons Attributions.

With Exercise, More Is Not Always Better!

If you’re anything like me, you work diligently to fit daily exercise into your routine. I try to run at least a few times a week, and I try to get in my 10,000 steps every day. I’ve trained for several half marathons and have even been determined enough to train for and run a full marathon once. Sometimes, I wonder if I’m doing enough. What about those people who run several marathons in a year? Those people who run up to 100 miles a week? If there’s a certain prescribed amount of exercise that we should get a week, then shouldn’t more be better? For your reference, the current advised amount of exercise is 150 minutes per week of moderate exercise (think: going for a walk after dinner) or 75 minutes of intense activity (think: running after work).  Are these people who exercise as much as their time allows healthier than I am?runner

Scientists recently followed a cohort of people who had survived heart attacks and were currently engaging in daily exercise. Because the people did different types of exercise, the scientists used a formula to equate the efforts exerted. For example, if one person was a runner and the other was a walker, the walker would obviously have to walk further in order to get the same benefits as the runner. The results showed that as long as the people were running less than 30 miles a week (an equivalent to walking less than 46 miles a week), they had a 65% decrease in death due to cardiovascular trauma. However, more exercise proved to increase the risk of death. Even more striking, the preponderance of a cardiovascular event leading to death sharply increased with each incremental uptake in the amount of exercise. In layman’s terms, if someone was running more than 30 miles per week, the likelihood of death due to a heart attack or other cardiovascular event sharply increased with each extra mile run.

The one caveat to this study was that the cohort was heart attack survivors, not the general population. However, the scientists did note that there competitive running events and other events of similar caliber also had a higher incidence of death due to a cardiovascular event as opposed to more relaxing sports.

So, what advice should we take from this study? Exercise. Not too much. Not too little. And be sure to get a rest day in here and there!

Article Source:

Elsevier. “Contrary to popular belief, more exercise is not always better.” ScienceDaily. ScienceDaily, 12 August 2014.

Image Source: Alan Hood. “Male Runners”  9 September 2008 via Flickr. Creative Commons Attributions.

We’ve Arrived — At Last!

This week, the European Space Agency’s Rosetta spacecraft finally arrived at comet 67P/Churyumov-Gerasimenko after a decade-long journey. Why did it take so long to arrive at the comet, which is located just between Mars and Jupiter? Flying in space is quite a bit different from driving your car on Earth. For one thing, there are no gas stations in space with which to refuel your spacecraft. Scientists need to come up with the perfect trajectory that will get a spacecraft to its destination using only the fuel available at launch. At this time, no rocket can carry enough fuel and still be light enough to propel Rosetta all of the way to the comet. Therefore, Rosetta had to use gravitational boosts from the sun, Earth, and Mars by doing multiple fly-bys to gain enough speed and the appropriate trajectory to rendezvous with the comet.

Rosetta

Now that Rosetta is circling the comet, the real experiments of the mission can begin. Comets have a distinctive tail of dust and gas that are blown off of the comet’s nucleus by the sun’s energy. One experiment will be to study this tail and see how it changes as it nears the sun while another will study the bright gases encircling the comet in its entirety. Finally, in November 2014, Rosetta will send a lander down to the comet to study it from within.

Why did scientists go through all of this trouble in order to study a comet? The mission obviously took many years of planning and maneuvering just to get to the point where the spacecraft and the comet rendezvoused. Comets are some of the oldest objects in the solar system. They can originate from the furthest edge of the solar system. Even though this mission seemed quite difficult and intense, it is much less so than traveling to the edge of the solar system. Studying a comet as it approaches the inner planets gives us a glimpse of what the outer reaches of the solar system contain.

 
In this same line of thought, my brain went to the Voyager spacecraft, which are the furthest manmade objects from Earth at this time. Have they reached these outer edges of the solar system from which comets arise?

Oort

Comets come from two regions of the solar system: the Kuiper belt and the Oort cloud. The Kuiper belt is the origin of the short-period comets, such as the one that Rosetta is orbiting. The Kuiper belt is a donut-shaped region that extends just beyond Neptune. The Voyager spacecraft have been in the Kuiper belt. The Oort cloud is much further and can really define the edge of the solar system. This is a large shell of billions of comets and other icy remnants of the early solar system. So, the question is “Where is Voyager 1, the furthest spacecraft?” Because of the large expanses of space, Voyager 1, while it is said has left the solar system, has only left the heliosphere. However, it has not even entered the Oort cloud. The answer to when Voyager 1 will exit the solar system and leave beyond the Oort cloud is estimated to be about 14,000 to 28,000 years from now!

 

Article Sources:

http://science.nasa.gov/science-news/science-at-nasa/2014/06aug_rosetta6/

http://www.esa.int/Our_Activities/Space_Science/Rosetta/The_long_trek

http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Voyager_1&Target=Beyond

 

Image Sources:

DLR German Aerospace Center “Landung von Pilae auf dem Kometen” 14 January 2014 via Flickr. Creative Commons Attributions.

NASA Goddard Space Flight Center “Solar System, In Perspective” 12 September 2014 via Flickr. Creative Commons Attributions.

Sperm That Attacks The Female? Say It Isn’t So!

Growing up in the Midwest, it was common knowledge that if you have a horse mother and a donkey father that the offspring will be a mule. Mules, however, are sterile creatures. This stems from the fact that a horse has 64 chromosomes and a donkey has 62 chromosomes; therefore, the mule is a mixture of the two with 63 chromosomes. When a mule goes to mate, chromosomal misalignment occurs and the embryo will not be viable. This is the normal course of interspecies breeding.

Today, I read a very interesting article about interspecies breeding of worms of the genus Caenorhabditis. In this experiment, researchers took worms of different species to see what the mating outcome would be. Unlike the mule story from above, no offspring were produced. More strikingly, the females were sterilized after mating with a different species and oftentimes died as a result. What could cause such a drastic result in the worm?

Elegans

Using fluorescently stained sperm from one species, scientists imaged a female worm from another species after mating. They found that the sperm were bursting through the uterus and attacking the ovaries! Not only that, but some of the sperm were even traveling through her entire body, causing tissue damage and eventual death!

Scientists believe that what they’ve termed “killer sperm” arise from a difference in agility between the species. When a male mates with a female, he may not be the only one; therefore, his sperm need to outcompete the rest in order to fertilize the eggs. Some species may have evolved to have stronger and more virulent sperm. In this case, if that male were to mate with a female that had not also evolved to withstand such an attack, his sperm would cause damage to the female’s body. Interestingly, they found that females who were accustomed to “gentler sperm” had ways to sense and avoid males with “killer sperm.”

I was glad that this study used “killer sperm” in both females that mate with other males and females that mate with themselves (hermaphrodites). I would have liked to see the opposite: females with the stronger uterus that is made to withstand the “killer sperm” mated with males with “gentler sperm.” Would they be able to mate and produce offspring? Or, is there another mechanism in these females preventing such embryos from being viable?

Article Source: University of Maryland. “‘Killer sperm’ prevents mating between worm species.” ScienceDaily. ScienceDaily, 29 July 2014.

Image Source: AJ Cann. “Caenorhabditis elegans” 4 December 2008 via Flickr. Creative Commons Attributions.

“Sixth Mass Extinction Event” Beginning?

When I was a child and went to the zoo, my favorite habitat to encounter was the African grasslands. From my favorite, the large, slow, lumbering elephant, to the more agile zebras, these animals never failed to capture my attention. What would we do if these animals were no longer on Earth? Would that affect our day-to-day lives or would we just have a less-than-stellar trip to the zoo?

Elephant

A recent story published last week detailed some of the cause and effects linked to what researchers are terming the “six mass biological extinction event.” We’ve all heard of such animals as the dodo bird becoming extinct, but I was astounded to learn that over 300 land animals had become extinct in the last 500 years. Probably less surprising to you is the fact that this is not because of a large meteor hitting the Earth as probably happened when the dinosaurs became extinct. Unfortunately, this decline in animal numbers has mostly been attributed to human encroachment and industrialization.

The animals that are at the most risk currently are the large animals of the African continent. Larger animals have longer gestations and smaller birth numbers, so as some animals die, it becomes more and more difficult to keep pace. Subsequent consequences to the endangerment of these animals include an increase in the number of small animals such as rodents taking over their living areas. Rodents carry many parasites and are host to several diseases that can infect other breeds and humans; as their numbers increase, infection rates are sure to increase, too!

Not only are the large animals impacted by human interference, but scientists have also seen a decline by nearly 50 percent in invertebrates such as insects and worms. What would happen if these animals became extinct? Insects are essential to the world crop and food production, as they are needed for pollination. Worms help to fertilize the soil in which the crops are planted. Without these species, there could be large and widespread impacts on human food production.

We need to think outside of the obvious when it comes to animal extinction. Sure, losing any species would be unfortunate, but there are wide-reaching consequences of just one or two species being eliminated. At the rate we are going with hundreds of species going extinct in the last half century, this really could be a mass extinction event. I only hope that the last 500 years are not indicative of the next.

Article Source: Stanford University. “Biologist warn of early stages of Earth’s sixth mass extinction event.” ScienceDaily. ScienceDaily, 24 July 2014.

Image Source: Jim Frost “Elephants 2” 19 October 2013 via Flickr. Creative Commons Attributions.

Early Universe Boiled Like Water

When I read today’s article, I instantly thought of the movie Men in Black. My brain shot to the scene in the morgue where a tiny alien living in the head of what appears to be a human gives Will Smith the cryptic message “The galaxy is on Orion’s belt.” Later, of course, we learn that there was an actual galaxy in an orb that is attached to the collar of a cat named Orion. The final scene of the movie also came to my mind today. The camera zooms out, from Earth through the solar system and our galaxy, to realize that our galaxy is also enclosed in an orb. This time, however, there are aliens using many orbs containing galaxies in a game of marbles!

Today’s article isn’t saying that the universe is exactly like we saw in Men in Black; however, the title of the article “Is the Universe a Bubble?” was what sparked my memory. The author equates the early universe around the time of the big bang to be like a pot of water sitting on the stove. As the water boils, and as the universe radiated with extreme energy, bubbles begin to form. Inside each “universe bubble,” a vacuum was produced, causing each bubble to expand. Many bumped into each other to melt together to make larger bubbles; some remained far apart. No matter which sort of bubble, the researchers are trying to explain that inside each bubble was a separate universe. Now you can see why I recalled those scenes from Men in Black!

Water

Have you never heard of this theory? Have you always only heard of the big bang? Don’t worry, you’re not alone! This theory of cosmic inflation is not widely accepted, mainly because instead of saying that the big bang began with a tiny, condensed piece of matter, scientists are saying that the cosmic inflation began with a vacuum. This gives some people pause.

Galaxy

Large particle colliders are where scientists try to test their big bang theories. Scientists at the Perimeter Institute are trying to test their cosmic inflation hypothesis. Using computer simulations, scientists are currently testing the scenario of two bubble universes merging together. Then, based on what their simulations show, they can search the skies for evidence for their theory. For example, if two bubble universes collided, scientists predict there would be a blemish of microwaves to detect; unfortunately, no such radiation has been discovered yet. Scientists will continue their work, however, because they believe that the simulations are showing that the bubble universe could actually be possible. They just need to find the correct marker in the background radiation of the universe to prove their point!

Article Source: Perimeter Institute. “Is the universe a bubble? Let’s check: Making the multiverse hypothesis testable.” ScienceDaily. ScienceDaily, 17 July 2014

Image Sources:

Scott Akerman “Boiling Water” 6 September 2008 via Flickr. Creative Commons Attributions.

Terry Hancock “M33 Triangulum Galaxy” 7 October 2011 via Flickr. Creative Commons Attributions

Early Detection Is Often The Key

In general, the earlier that your doctor diagnoses you with a disease, the higher your chance of survival or improvement. We see this everyday in instances of cancer and heart disease. When caught at the late stage, the prognosis takes a steep decline. The same paradigm holds true for mental illnesses. The earlier that treatment can be started, the better the outcome.

Alzheimer’s disease is a debilitating ailment with progressive decreases in mental acuity and increasing dementia that normally occurs in the aging population. Like many diseases, Alzheimer’s worsens over time. Early diagnosis is not always possible because the first signs and symptoms are often brushed off as “old age.” The disease progression differs from person to person, but it ultimately leads to a loss of both short- and long-term memory followed by a loss of bodily functions and death. A final and definitive diagnosis of Alzheimer’s disease is done by examining brain tissue for the accumulation of amyloid plaques; unfortunately, this is very invasive and can only safely be done after death.

Obviously, the search for biomarkers is currently an area of intense research not only in Alzheimer’s disease but across many disciplines. The thought is that if there was a certain marker of disease that was elevated in an easily accessible bodily compartment (for example, the blood), then routine tests would be able to predict who would and would not get a disease. For Alzheimer’s, the stand-out compound would be the detection of amyloid plaques. For example, a molecule that could bind to the amyloid plaques could be injected into the patient, and a scan of the brain would show plaque accumulation. Another form of tests that are being researched include compiling characteristics of Alzheimer’s patients including the size of multiple parts of the brain. If a pattern is found, this could prove useful to early diagnosis.

SmellAll of these ideas are good and well, but what about the costs associated? Are insurance companies going to pay for all of these expensive tests when there is not a very convincing lead? What if I told you that scientists were currently working on a very simple and cost-effective means to identify who would need more expensive testing? A group from Columbia University did a very large study involving patient’s ability to detect smells over a period of time. They found that those who began to lose their sense of smell had a significantly increased probability of being diagnosed later with Alzheimer’s disease and dementia.  A separate study from Australia that is in the early stages is trying to find a method of early detection via eye examinations. In this study, a patient would take a compound that binds beta-amyloid and then fluoresces. The doctor would then scan the eye to detect fluorescence.

Both of these studies are very interesting, but I most like the one associated with smell. What an easy test! I would like to see it expanded in order to make a definitive claim, but it looks to be on the right track!

Article Source: Alzheimer’s Association. “Smell and eye tests show potential to detect Alzheimer’s early.” ScienceDaily. ScienceDaily, 13 July 2014.

Image Source: Dennis Wong. “Smell” 22 February 2009 via Flickr. Creative Commons Attributions.