Race for the Double Helix

James Watson and Francis Crick had an article posted in the popular science magazine, Nature. This particular article led them to become Nobel Prize winners. This article contained the most important discovery of the 20th century. Watson and Crick worked 18 months to make this possible, with much help from other scientists' research. Their discovery: the structure of DNA. At the time no one even knew if DNA or protein was the key to inheritance. The movie, Race for the Double Helix, shows the events that made this Watson's structure possible, leading up to the publication of the Nature article.

Watson and Crick's article came with much skepticism from the scientific community, as was expected with such an outstanding feat. They start by explaining why other scientists models are flawed and therefore cannot be the structure. They cite how Pauling and Corey's nucleic acid model consisted of three chains, with phosphates near the fibre axis, and bases on the outside. Watson and Crick believed that this could not be true since the X-ray diagrams show the salt, not the free acid, and some of their van der Waals distances seem too small. They also comment on Fraser's suggestion of a three-chain structure where phosphates were set on the outside and bases on the inside, linked with hydrogen bonds. Due to the lack of information, however, they do not explain why this model cannot work. After identifying the flaws of these previously suggested structures, they go on to suggest their own.

The major significance of the Watson~Crick model was the double helix: two helical chains coiled around the same central axis. The chains run opposite each other due to the dyad laying perpendicular to the fibre axis. Because they run opposite each other, the sequence of one side determines the sequence of the other. The novel feature of the structure is the manner in which the two chains are held together by the purine and pyrimidine bases. The planes of the bases are perpendicular to the fibre axis. They’re joined together in pairs, a single base from the other chain, so that the two lie side by side with identical z-co-ordinates. One of the pair must be a purine and the other a pyrimidine for bonding to occur. (Watson. Crick., 1953)

Bibliography

Watson, James, and Francis Crick. "A Structure for Deoxyribose Nucleic Acid." LionBook. 25 Aug. 2003. Web. May 2011. <http://faculty.fullerton.edu/kkantardjieff/C340/DH-Paper.pdf>.

A Woman's Place...In Science

The early 1900's were not good to women who wanted a career outside the home, especially if that career came in the field of science. Rosalind Franklin knew this all too well, being a female scientist researching DNA's structure and function in genetic inheritance. She was nearly at a breakthrough when her work was shown to another scientist, James Watson, who ultimately took the credit for the discovery of the DNA's double helix formation (along with Francis Crick and Maurice Wilkins). There has been a lot of controversy about whether Franklin was unfairly left out of the spotlight for helping with the discovery or not.

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Some make the claim that it was the work of Rosalind Franklin that secured the evidence needed for Watson and Crick to make the discovery of the DNA helix. Franklin had been taking photos of DNA using X-ray crystallography. It was her photos that were shown to Watson. "At one point, Wilkins showed Watson one of Franklin's crystallographic portraits of DNA. When he saw the picture, the solution became apparent to him, and the results went into an article in Nature almost immediately. Franklin's work did appear as a supporting article in the same issue of the journal." (Rosalind Elsie Franklin: Pioneer Molecular Biologist, 2011) Franklin was the scientist who figured out how to separate the A and B forms of DNA, and discovered important basic facts about it. She discovered that the sugar-phosphate backbone was on the outside of the molecule, and that the DNA had two strands. "She gave quantitative details about the shape and size of the double helix. The all- important missing piece of the puzzle, that she could not discover from her data, was how the bases paired on the inside of the helix, and thus the secret of heredity itself." (Ardell, 2006).

In my opinion, Franklin did not get the credit she was due. She did all the work, with the exception of discovering how the bases were paired. However, I believe that if she had been given enough time without others stealing her work, she would have discovered the order of the bases. She was a brilliant, intelligent scientist who was dedicated to her work. She was thorough and serious about her discoveries, and did all she could to back all of her claims with clear and concise evidence. She was not willing to make guesses about the solution; she was determined to find out why it was that way. Watson was lucky enough to be shown her photos, and with her information and the information from other scientists he was able to make such a conclusion. The only problem and defense for Franklin not being credited was the fact that she died the year that Watson, Crick, and Wilkins were awarded the Nobel Prize. "...because the Nobel Prize is not awarded posthumously, Rosalind Franklin could not be cited for her essential role in the discovery of the physical basis of genetic heredity." (Ardell, 2006). I still believe that it would have been a great honor for her to be cited as a partial Prize winner, as an exception due to such a breakthrough discovery.

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This controversy has occurred elsewhere in the science community as well. Just last year there was a dilemma about a meteorology professor accused of stealing emails containing climate research and information that belonged to Great Britain's University of East Anglia Climatic Research Unit. Scientists might prevent this type of controversy in the future by simply being loyal and ethical in research. Since we know this is not always the case, codes and guidelines should be enforced. It is up to the companies and scientists to check power and keep an eye out for wrongdoers.

Bibliography

"Rosalind Elsie Franklin: Pioneer Molecular Biologist." San Diego Supercomputer Center. Web. 10 May 2011.< http://www.sdsc.edu/ScienceWomen/franklin.html.>

Ardell, David. "Rosalind Franklin." Access Excellence @ the National Health Museum. 25 Oct. 2006. Web. 10 May 2011.< http://www.accessexcellence.org/RC/AB/BC/Rosalind_Franklin.php.>

"University Clears Michael Mann on Stolen Email Allegations." Union of Concerned Scientists:Citizens and Scientists for Environmental Solutions. Union of Concerned Scientists, 3 Feb. 2010. Web. May 2011. <http://www.ucsusa.org/news/press_release/university-clears-michael-mann-stolen-emails-climategate-0346.html.>

Nelson, Bryan. "Watson On: The Discovery, The Controversy, The Legacy". Newsday, Inc. 28 Jan. 2003. Print.

Gattaca and Genetic Engineering

Gattaca is an intriguing science fiction movie about genetic engineering. It portrays the advantages and disadvantages of genetics in an exciting way. Is genetic engineering right? Everyone has their own opinion on the matter, as with many other controversial issues. In my opinion, there are only specific instances where I would ever even consider genetic engineering. The question will never die, and will most likely be debated for centuries. It's a touchy subject, but someone has to blog it.


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There are some advantages to having a society like the one portrayed in Gattaca. As shown in the movie, genetically engineered people would be genetically inclined to be good at specific things. Each company would have "the best of the best" working for them. There would be no genetic defects, no diseases, no illness for people to deal with. The probabilities in each life could be calculated based on their genetic sequences. It would also help keep crime rates down, as genetic engineering could take out the genes that cause aggression and other unwanted traits.

There are also many disadvantages to genetic engineering. In the movie, the main character, Vincent, is an "in-valid", meaning he was not a genetically engineered baby. Because of this he was never allowed to follow his dreams of going into space until he fraudulently posed as a "valid". The society in Gattaca never let him attempt his dreams, although he shows that he is mentally capable of achieving them. The only thing that mattered was his DNA sequence, just another way society would discriminate. Genetic engineering leaves out those with disabilities, who are unique and essential to society. If we were able to exclude the eccentric, the different, the misfits, and the weak, we would all be the same. There would be no individualism, none of that crazy diversity that makes life fun and unique. Genetic engineering leaves the struggle out of life, and more often than not, people grow and understand things through struggles and mistakes. We would have generation after generation of individuals who do not appreciate the glory of life: genetically engineered robot-humans. Too many people would leave their lives to the realm of possibility, instead of taking their lives into their own hands, and carving their own destinies.

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I personally do not believe genetic engineering should be used at all. If there were any limits placed on genetic engineering, I think it should be used strictly for diseases and life threatening defects. I simply feel that humans are not mentally capable of fixing all the flaws that I am sure will come surface. The consequences just seem far too varied and unpredictable. History shows that when humans play God it never ends well. The famous saying goes "everything happens for a reason". Mother nature has a way of always putting things back the way they should be. That could be very complicating for the genetic engineers.

Lava Lamps in the Lab

Lava lamps used to be essential to the properly furnished 60's style room. Now they can be found and bedrooms and dorms. But where did they come from, and who invented such a retro luminescent? For starters, this mystical art piece was invented by Edward Craven Walker, after 15 years of trying to make a liquid motion lamp that could be mass produced. He got the design idea from a contraption he saw in a pub in Hampshire, England. This contraption had been invented by Mr. Dunnett. Initially retailers found the lamps to be ugly and disgusting, but the "Psychedelic Movement" and the "Love Generation" of the 60's made merchandise like the lava lamp fly off the shelves. He and his company, the Crestworth Company of Dorset, England, marketed the lamp in Europe under the name of Astro Lamp.Two Americans bought the rights to manufacture the lamp in North America, calling it the Lava Lite lamp.

Commercial lava lamps contain a regular incandescent bulb, wax, and water, all contained in a glass bottle. The bulb heats the wax, making its relative density decrease and blobs of wax float to the top, where they cool and ascend back to the bottom. Usually, a wire coil in the base of the glass breaks the surface tension and recombines the blobs of wax. 



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Homemade lava lamps can be made in a simple science experiment, as I did in my biology class. All that is needed is a large empty bottle, food coloring, vegetable oil, water, and Alka Seltzer tablets or salt. I used Alka Seltzer in my experiment. First, the empty container is filled 3/4 with oil. Then water is added to fill the container the rest of the way. As most would easily observe, the oil "floats" on top of the water. This is because oil is less dense than water, and is hydrophobic. The next step is to add a couple drops of food coloring. The food coloring sinks down to the water because food coloring is hydrophilic (water "loving"), so it bonds with water, not oil. The last step is to add the Alka Seltzer, and watch the "lava" flow! The tablet's reaction to the water pushes the water upwards through the oil and mixes the food coloring and water, creating the lava. The water flows in blobs of colored water as the oil pushes the water away from it and back down.

 

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Disinfectants, Antiseptics,and a Gross Little Petri Dish

We recently completed a lab on disinfectants and antiseptics, and my results were surprizing (and gross!). Disinfectants are chemicals used to kill bacteria on non-living objects like surfaces, whereas antiseptics are chemicals used to kill bacteria on the body. Antiseptics are usually much less harsh, but sometimes lack the power to kill all the bacteria because of this. In this lab, we used the disinfectants alcohol and bleach, and the antiseptic soap to see if the difference in effectiveness of the products. We were to take samples of both our hands and a surface of our choice.

First, I divided my petri dish into six sections. For the first section, I swabbed a portion of my finger and streaked the petri dish with it. Then I put my swab in alcohol and swabbed a different finger, again streaking the petri dish with the swab. Then I washed my hands with soap and swabbed another finger, applying it to the petri dish once again. Next, I tested a water fountain at the school. I swabbed it once with distilled water, once with an alcohol tip, and once with bleach. Everytime I streaked the petri dish with the swab. After about 72 hours, I had growth in my dish. Growth was low with my skin control, none with my alcohol section, and moderate with my soap section. In my surface sections: the control had low growth, and the alcohol and bleach sections had no growth at all.

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I concluded that the best disinfectants for surfaces are alcohol and bleach. The least effective is water. The best antiseptic is alcohol. Soap had the least effect, so I conclude that it is the least effective antiseptic. It's also nice to know that our water fountains are clean! Good job janitors! =)

Things that could have effected or scewed the results of my experiments: the janitors clean the fountain everyday, I was not able to dry my hands after washing them, and the length of time I washed my hands was not recorded.

"Can You Hear Me Now??..Good!"

Bacteria are everywhere. Some are beneficial to us, and some harmful. Before the past decade, scientists believed that bacteria mostly worked individually. Scientists were unaware of the communication techniques bacteria have between each other. Today, with much credit given to scientist Bonnie Bassler, we are beginning to understand the communication efforts of bacteria. In the interview/article "Bacteria Talk", she explains how this communication, called quorum sensing, works.

In general, she studies how bacterial cells can "talk" to each other through chemicals and how they can form large groups that function in unison. As bacteria divide and grow, each releases small amounts of chemicals called auto-inducers. With just a few bacteria releasing this, the molecule floats away, but when there is a large amount of the molecule present, all the bacteria start grabbing onto it with their receptors. The bacteria recognize the other cells and change their gene expression to be more compatible and in unison with each other. Bassler says that "essentially quorum sensing allows bacteria to be multi cellular."

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Bassler started her observations and experiments using a harmless marine bacterium that produces bioluminescence called Vibrio harveyi. These bacteria make enzymes that produce photons of glowing blue light. Bassler used their visual aids to help observe the way they chemically communicated. Eventually, it was Woody Hastings who made the observation that when the bacterium was diluted down to only a few cells, the bacterium did not produce light. However, when a greater number of cells were added, they started producing light together.

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Bassler is working on important next steps in quorum sensing. She is trying to find out if it is possible to control quorum sensing, and if it can be useful in things like antibiotics. It is possible that scientists could figure out how to use this idea to control the natural bacteria that is in and on each human as well. There are millions of bacteria that help in the digestion, on the skin, and throughout the whole body. If we could control those bacteria, we could better protect ourselves from the bacteria and viruses that make us sick. Bassler's dream is to create an anti-quorum sensing drug. She loves her work and enjoys the students she works with to accomplish this goal and many others.

Kwashiorkor, Diets, and Dangers

Kwashiorkor occurs when a person if severely protein deficient, more specifically, deficient in complete proteins. It is a very serious condition that should not be overlooked. Although not prevalent in the United States, other countries suffer daily from its effects. Knowing whats behind this can help us to prevent it.

Complete proteins are the only providers of the essential nine amino acids that our bodies cannot produce themselves (at least in sufficient amounts). A lack of these amino acids and complete proteins leads to slowed growth rate, bloated stomach from body fluids, spindly arms and legs, listlessness, and possible death if not treated. The skin may lose its natural color and develop dark patches. Most also suffer from anemia and vitamin deficiency.

It usually affects young children from 1 to 3 years of age. These are the children who need complete proteins the most since their bodies are constantly growing, and ultimately suffer the most when they cannot be provided such nutrients. Kwashiorkor is prevalent in urban areas and developing countries where foods high in complete proteins are not as readily available like Zimbabwe. The treatment for this disease is to supplement the diet with high-protein foods like dried skim milk. Most survivors never reach their potential physical growth, but that must be better than the death that hovers without treatment.

There are also many dangers associated with low carb diets. CBS News covered a story about a study done on high-fat animal proteins and their health risks. In low carb diets you're advised to limit bread and other carbohydrates, but eat more meats and eggs. The study shows that this leads to a higher risk of cancer and even death. This high protein, high fat diet needs to be with plant-based carbohydrates instead.Tofu, almonds, avocados, whole grains, veggies, and fruits are good sources because they have low carbs and low harmful fats.

Exercise physiologist Greg Landry tells the Sideroad that there are fifteen scientifically measured reasons to avoid a low carb diet. Among these are risks due to depletion of glycogen storage and insufficient vitamin intake. Low carb diets deplete healthy glycogen stores in the muscles and liver, causing dehydration and muscle loss, not actual weight loss. This causes fatigue that leads to muscle atrophy. Low carb diets do not allow carbohydrates that are used as fuel in the body. If insulin levels get too low, breakdown of muscle protein increases and protein synthesis stops. Also, loss of muscle causes a decrease in your basal metabolic rate, so fewer calories get burnt. Low carbs leads to more protein foods and too much fat content in the diet. These diets lack fiber, sufficient quantities of nutrients, and antioxidants that actually help prevent cancer and heart disease.

Too much protein can be harmful to your body. Adding more protein but not more calories or exercise may put your body under stress. Increasing protein and calorie intake, but not increasing exercise will build an equal amount of additional fat and muscle mass. A diet that has more than 30% of caloric intake causes a build up of toxic ketones that can put extra stress on your kidneys.

Protein is essential for a healthy body, but too little or too much can cause dangerous side effects. Severe protein deficiency causes kwashiorkor. Low-carb diets cause risk of cancer. Too much protein causes stress on the organs. Protein is great for our muscles, bones, teeth, skin, hair, etc.. It can help yet harm in the same instance.