LAVA

Recently my biology class did a lava lamp lab! We used a water bottle, vegetable oil, tap water, food coloring, and Alka Seltzer tablets. So, it wasn't an actual lava lamp...but it was pretty fun and easy to make! After doing our lab, we were asked to research the science behind a real lava lamp.

Interestingly enough, a real lava lamp isn't much different from the ones we made. The theory behind how a lava lamp (also known as a "liquid motion lamp") is that there are two liquids involved that are very close in density, and insoluable to one another. When you pour water and oil into a container, the water will sink below the oil due to the water having a higher density than the oil. Water and oil do not mix because an oil molecule is hydrophobic, or water fearing, so its molecules do not bond to the hydrogen molecules of the water.

When we added the food coloring, it only adhered to the water because the food coloring is hydrophilic, or water loving. The food coloring is able to bond to the water molecules, and thus the oil remains colorless. This is the same as in a real lava lamp. When you see the globs of "lava" bubbling and floating, you are really just seeing colored water ---sorry if you thought there was actual lava in lava lamps and I just spoiled your fun!

To actually make our "lava", we added Alka Seltzer tablets which chemically reacts when dropped into water because it contains citric acid and sodium bicarbonate, which produces the "fizz". This fizz was the energy source that moved our colored water to the top of the oil, and then the water sank back to the bottom of the water bottle, below the oil.  In a real lava lamp, the energy source is the heat from a light bulb. When the water becomes heated, it becomes less dense and floats to the top of the oil. As it cools down, it returns to its original location below the oil. This process continues, and gives the lava lamp it's unique characteristic.

Quorum Sensing

Many people have never heard of the term, "quorum sensing", which is most likely because it is a relatively new concept. Princeton's Bonnie Bassler and her team of scientists (which consist of her students) have developed a theory of how bacteria communicate with eachother. PBS got an excellent interview with Bassler a few years ago.

 So how exactly does quorum sensing work? Well, as the bacteria grows, it releases a small amount of chemicals called "auto-inducers". The chemical is proportional to the amount of bacteria cells. At first there is just a small amount of the chemical floating around, but after the cells replicate there is more of this chemical. The bacteria can sense with antennae-like sensors on their membrane that there is a significant amount of auto-inducers, and they begin to grab it and take hold. Because of this sensing, they now know that there is enough bacteria cells to do some damage, so to speak. It's basically like the concept that there is "strength in numbers". If just a few little bacteria cells released toxins into the body, it would be very easy for our immune system to identify that there is a toxic foreign substance in our body and fight of the bacteria, but when there is an unfathomable amount of bacteria it is harder for our immune system to fight it off. Your body is covered with bacteria! Your gut alone contains 10¹⁰ bacterial cells. Don't freak out and go stock up on antibiotics--many of the bacteria found in your body are helpful. People used to believe that bacteria cells were asocial, meaning they do not communicate between eachother, for they are unicellulor organisms. They only have one piece of DNA inside of them, making them the simplist for of organism. Bassler questioned the bacteria's actions and the body's response once being attacked: why doesn't the body fight of the bacteria as soon as it releases toxin? It would be much easier to fight off bacteria before it starts asexually reproducing and replicating. After much research, her team discovered that the bacteria chemically communicates with eachother and waits to release toxins until there are roughly 10⁸ or 10⁹ acting against you simultaneously. Smart, huh? It makes it much harder for the body's immune system to fight off such an extravagent amount of bacteria cells, compared to just a few hundred.

There is a certain type of bacteria that is responsible for bioluminescence called Vibrio harveyi.  It produces light due to quorum sensing. Bassler's team discovered that single cells of Vibrio harveyi do not illuminate by themselves. They wait until they have more cells in their colony before they illuminate.

Bassler hopes to some day be able to control quorum sensing and be able to put it into a practical application, such as making insulin from good bacteria and pro-biotics to help us from getting sick in the first place.

                                                      

Videos of the Day

http://www.ted.com/talks/jake_shimabukuro_plays_bohemian_rhapsody.html

I do realize that this video is completely unrelevant to biology, but I stumbled across this video from the website, Ted.com, and I loved it! I'm already a huge Queen fan, and Bohemian Rhapsody is such a classic, but the fact that he did this on a ukulele is amazing! I hope you enjoy it!


---Okay, so I just went back to ted.com and discovered a video that is completely relevant to biology!! It is really quite stunning, and it brings life to that which brings life to us....our cells! I will copy and paste the link below, but for the first 7 minutes or so of the video David Bolinsky (the creator of this amazing video) is just talking about his actual video that animates the cell. You don't get to see his video until he is through with talking about it, but bear with it, for it is truly fascinating.

http://www.ted.com/talks/david_bolinsky_animates_a_cell.html

--He stated in the video that this is basically a "Reader's Digest" version of the real thing.

Cutting Back Carbs? Think Again!

            Kwashiorkor is a malnutrition that occurs when there is a deficiency of protein in your diet. You many times see children with Kwashiorkor with 'inflated' looking stomcahcs. It is very rare in children in the United States, but is very common where there has been famine, a limited food supply, and where people receive low levels of education (people do not understand how to eat a proper diet when they are undereducated). Based upon the previous sentence, you can understand why Kwashiorkor is predominantly found in very poor, third-world countries. Often times during an environmental disaster, such as a drought, earthquake or hurricane, there is a lack of food which then leads to more cases of Kwashiorkor. There are very few reported cases of children with Kwashiorkor in the United States, however there may be as many as 50% of elderly people in nursing homes that do not receive enough protein in their diet.  Commonly, when there are cases of Kwashiorkor in children in the United States, there is also extreme child abuse and neglect.

            There are three main types of food that provide energy to the body – protein, carbohydrates and fats. Humans and animals do no produce protein, therefore we need to obtain it by ingesting foods such as cheese, egg, fish, meat, milk, legumes and nuts, which are all very high in protein. You probably already know that protein is a very essential part of your well-balanced diet, but you may be wondering how your body uses protein. Well, your body uses proteins to build, maintain and repair cartilage, muscle and other tissues in your body. Proteins called antibodies help fight off diseases that try to attack the body. The proteins in our blood, called hemoglobin, carry oxygen from our lungs to other body tissue. Did you know that hormones are a type of protein? They control processes such as growth, development, and reproduction. If you do not obtain enough protein, your body will use proteins from the cells of your liver and muscle tissue, which can permanently damage those tissues and even be fatal.

            Proteins produce about 1,800 calories of energy per pound, the same amount provided by carbohydrates. So, this means that if you are thinking about losing weight, then you can completely cut out carbohydrates and just eat a lot of protein? Wrong! There are so many dangers from eating a high-protein, low-carbohydrate diet! Many people think that cutting back on carbohydrates will help them lose weight. They are actually correct. If you stop eating carbohydrates, you will see a dramatic amount of weight loss when you step on the scale, but don’t let it fool you!

            A low carb diet will deplete the healthy glycogen stored in your muscles and liver. So you are losing muscle and also dehydrating your body, which makes the scale drop significantly even though you haven’t exactly had fat loss. Did you know that metabolism (metabolic rate) happens in your muscles? Since you just suffered from muscle loss due to the depletion of muscle glycogen, your metabolism slows down, which means few calories burned. Thus, over time it is much harder to keep the weight off because your metabolism is slow and you are fatigued, so you don’t have the energy to exercise. You now are a storage center for all that protein that you are eating, which, if you remember, has the same amount of calories as carbs.

Nylon

http://www.americainwwii.com/stories/productwithlegs.html

WWII advertisement by B.F. Goodrich which says, "We Borrowed Their "Nylons" to Make Tires for the Navy." During World War II, the synthetic fiber, nylon, was used to make war products such as tires, parachutes, and rope.

Nylon and Polymers and Carothers, Oh My!

There is no doubt that two of the world's most highly used synthetic materials are nylon and polyester. They are very similar in structure too - both are made of polymers. In case you didn't know, a polymer (according to the Merriam-Webster Dictionary) is a chemical compound of mixture consisting essentially of repeating structural units. They can be found everywhere because plastics are made up of polymers and plastic is all of the world - from textiles to Tupperware! The man who was behind it all is, Wallace Hume Carothers.

Wallace Hume Carothers' education  after high school began at Capital City Commercial College at Des Moines, Iowa. After that, he attended a four-year program at Tarkio College in Missouri, where he obtained a bachelor's degree in chemistry. Lastly, he graced his presence at the University of Illinois, where he received his doctorate in 1924.

In 1928, the chemical firm, E. I. DuPont de Nemours hired Carothers as the director of a new research program. With his team of researchers, Carothers was able to engineer a synthetic polymer fiber out of a test tube. This fiber had many similar qualities as silk, which at the time was hard to obtain due to Japan being the United State's main source of silk and the United States was having political troubles with Japan. Therefore, this new synthetic fiber was exactly what the United States needed. Thanks to Carothers' knowledge in science (more specifically, chemistry), he was able to engineer it, and he named it, nylon.

Nylon was very revolutionary due to it being able to make many different objects, from parachutes to mascara. It's first real success came with it being used in women's stockings in 1940. Sadly, after the invention of pantyhose, the United States entered World War II, and nylon had to be used for military equipment, such as parachutes and rope, therefore, women had a hard time getting their hands on their beloved "nylons" (the name bestowed on pantyhose, or stockings). Even before it was used to make stockings, nylon was used to make tooth brush bristles.

Synthetic materials, such as nylon, polyester, acrylic, and polypropylene, have created a much wider spectrum of items that are available to consumers today. They have also decreased the price of many products, for they are no longer being made out of 100% silk, cotton or wool, which are more expensive to buy. People come into contact with numerous synthetic materials everyday. They are in almost all the clothes that we wear, our shoes, in the cars we drive,  and also in make up brushes. Have you ever asked yourself what our tooth brush bristles would be made out of if we didn't have these synthetic materials? What would we use for the bristles? Our clothes would be made out of all organic and natural fibers, thus making them more expensive.

 Luckily for us, however, we do not need to worry about such things, because we do have our synthetic materials, thanks to Wallace Carothers and his team of scientists!

http://www.pbs.org/wgbh/aso/databank/entries/btcaro.html

                                            Wallace Carothers 1896-1937