Category Archives: Medical Science

A Silver Bullet?

When my sister went to get her ears pierced over the summer, my mother recounted how, instead of using devices like the sterilized piercing guns used today, Indian people used to use thin wires of silver to pierce their ears because of its supposed antimicrobial properties. This intrigued me. Of course I had heard of molecules like penicillin that could kill off bacteria, but never before had I considered that a single, naturally occurring element would be able to accomplish the same. How does this seemingly benign molecule cause so much damage?

The transition metal itself is biologically inert; the real structural damage stems from its Ag+ ion. This is released when Ag comes into contact with moisture (Kenyon University & Garduque), and does its work inside the microbe itself. I stopped as soon as I read that last part. Something didn’t seem right. I had learned from my AP Biology class that the majority of cell membranes are hydrophobic. They consist mainly of a phospholipid bilayer with the polar hydrophilic heads facing outwards into the environment and inwards towards the cell’s cytoplasm, and the long, non-polar hydrophobic tails made of hydrocarbons chains in-between. These tails don’t like to let polar atoms and molecules in and out by themselves, and I thought it highly unlikely that microbes would have special protein channels built to let in damaging substances. So how did these Ag+ molecules get in in the first place?

figure_04_14_labeled

Figure 1: The Phospholipid Bilayer

(Midlands Technical College, n.d.)

A while of digging later, I had no definitive answer. Some research hypothesized that the ions got through via protein channels made for other ions (Kenyon University & Garduque), but since there wasn’t any conclusive evidence I still remained somewhat skeptical. I continued to research the effects of the Ag+ ions, tough, and the evidence I found in favor of its microbial properties was strong enough for me to overlook this tiny blip.

What I found was that Ag+ works in three major ways: by reacting with the disulfide (R-S-S-R) and sulfhydryl (R-S-H) groups of microbial protein structures, by interacting with the microbial DNA, and by damaging the membrane structures of the cells. In the first method, the interactions of the ion change the quaternary (outer) structure of some of the microbes key proteins and enzyme, leaving it unable to function properly. The ion reacts to form, “a stable S-Ag” bond with the sulfhydryl-containing compounds, which are involved in, “trans-membrane energy generation and ion transport,” located in the microbial cell membrane, and are also believed to, “take part in catalytic oxidation reactions that result in the formation of disulfide bonds,” which are key components of a protein’s outer structure. The latter doesn’t involve Ag+ acting as reactant, but rather as a catalyst between existing the oxygen and hydrogen portions of the sulfhydryl groups. This reaction also ends up releasing H2O as a product (Jung, Koo, Kim, Shin, Kim & Park)

500px-Quaternary_structure

Figure 2:“Structure of the protein 1EFN, with focus on the quaternary structure.”

(Wikipedia, 2012)

Next, while it is clear that the Ag+ ions do have effects on microbial DNA, it is unclear exactly how it interacts with the DNA. Some scientists suggest that, “…they interact preferentially with bases in the DNA (Jung, Koo, Kim, Shin, Kim & Park),” while others think that the ions’ various other reactions in the cell, “…lead to an increased production of reactive oxygen species,” that in turn damages the microbe’s DNA, eventually leading to its death (Morones-Ramirez, Winkler, Spina & Collins, 2013). Finally, the microbe’s increased cell membrane permeability, which is also said to occur as a byproduct of these reactions and subsequent metabolic disruption and homeostatic iron levels, which, “…[restores] antibiotic susceptibility to a resistant bacterial strain (Morones-Ramirez, Winkler, Spina & Collins, 2013).”It is important to note, however, that this does not reverse the bacterial resistance, only temporarily weakens it.

400px-FIGURE_3_Feng_et_al

Figure 3: “Figure 3. Treatment of cells with Ag+ results in DNA condensation, cell wall damage, and silver granule formation. (A) E. coli and (B) S. aureus cells with and without Ag+ treatment were observed with transmission electron microscopy (Feng et al., 2000).”

(Kenyon University, n.d.)

As much as it would be great to regard the Ag+ ion as an end to all our troubles, it’s not without its side effects. Some people are allergic to silver (Elsner & Hipler, 2006), and those that aren’t are in danger of having the element accumulate in their bodies (Fung & Bowen, 1996). Long-term intake can lead to increased levels of skin silver and/or silver sulfide particle levels. Sunlight causes these particles to darken, leading to a skin discoloration known as argyria (Elsner & Hipler, 2006). Furthermore, silver is no different from traditional antibiotics in that it is simply ‘another chemical’ in action. As such, it is plausible that overuse of it may eventually lead to increased silver resistance in bacteria, and then we would simply end up in the same place we are now with the antibiotic resistance problem; at best we’ll just delay our troubles. Still, since there’s little doubt in the actual antimicrobial properties of silver, all of this doesn’t completely take it off the table. If it were possible to distribute the dosages in a way to avoid some of the adverse side effects, we could take advantage of the aforementioned delay. Time is arguably the most valuable resource for humans, and with all of the major medical advances taking place in the modern age, that extra time might be just what we need to come up with a true solution.

Works Cited

Elsner, P., & Hipler, U. -. (2006). Silver in health care: Antimicrobial effects and

safety in use. Biofunctional Textiles and the Skin, 33, 17-34. doi: 10.1159/000093928

Retrieved from

http://www.karger.com/Article/Abstract/93928

Fung, M. C., & Bowen, D. L. (1996). Silver products for medical indications: Risk-

benefit assessment. Clinical Toxicology, 34(1), 119-126. doi: 10.3109/15563659609020246

Retrieved from

http://informahealthcare.com/doi/abs/10.3109/15563659609020246

Jung, W., Koo, H., Kim, K., Shin, S., Kim, S., & Park, Y.

(2008). Antibacterial Activity and Mechanism of Action of the Silver Ion in Staphylococcus aureus and Escherichia coli. Applied Environmental Microbiology, 74(7), 2171-2178 doi:10.11.28/AEM.02001-07.

Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2292600/

Kenyon University. , & Garduque, G. (n.d.). Silver as an antimicrobial agent.

Retrieved from http://microbewiki.kenyon.edu/index.php/Silver_as_an_Antimicrobial_Agent

Midlands Technical College. (Producer). The Phospholipid

Bilayer [Web Graphic]. Retrieved from http://classes.midlandstech.edu/carterp/courses/bio225/chap04/lecture5.htm

Morones-Ramirez, J. R., Winkler, J. A., Spina, C. S., & Collins,

J. J. (2013). Silver enhances antibiotic activity against gram-negative bacteria. Science Translational Medicine, 5(190), 198ra81. doi: 10.1126/scitranslmed.3006276

Retrieved from:

http://stm.sciencemag.org/content/5/190/190ra81

Wikipedia. (Producer). (2012, August 27). Protein structure with focus on the

quaternary structure [Web Graphic]. Retrieved from http://en.wikipedia.org/wiki/File:Quaternary_structure.png

Anesthesia, Safe or Not?

Throughout my life I’ve had a couple of surgeries. Every time I have received surgery, my mother always asked the doctor, “Do you have to use general anesthesia?”. In times like that I have always told myself, why does my mom even ask, of course the doctors are going to use general anesthesia, why not?  One day I asked my mother “Why do you ask the doctors the same question every time?”, and she told me that general anesthesia was very dangerous, and if it is unnecessary it would be better not to use it. This is why I chose to research general anesthesia. I would like to formulate my own conclusions about the dangers of general anesthesia. The way I will do this is through a careful analysis of the facts, side effects and the way general anesthesia works. I will also use my knowledge of chemistry to aid me in making my conclusion.

The functions of anesthesia include: analgesia (no pain), amnesia (loss of consciousness), impairment of skeletal muscle, and weakened autonomic responses. The most important part of anesthesia is that after the surgery all of these effects can be reversed.  Not all anesthetics will provide all of these effects. For example, barbiturates are not analgesics, but will bring loss of consciousness. This is often why most anesthesias are a combination of many anesthetics.

Anesthetics have many side effects. The first one is a decrease in respiration. Anesthesiologists deal with this by attaching all patients to ventilators during surgery. The second most common side effect is nausea, when a patient is under general anesthesia, their lower esophageal sphincter is relaxed. To avoid death by aspiration, doctors use endotracheal tubes to provide ventilation.

Endotracheal tube

Picture 1: Endotracheal Tube

The third side effect is hypothermia. To prevent this side effect is one of the major goals for anesthesiologists. Anesthesiologists prevent hypothermia by warming the fluids (anesthesia), which are injected into the human body.

How does anesthesia work? Anesthetics block certain protein receptors, inhibiting the protein from performing its task. For example, the NMDA (N-methyl-D-aspartate) receptor is one of the main mediators of excitatory neurotransmission. The receptor is an ion channel, which permits the movement of calcium, sodium and potassium across the post-synaptic membrane. Anesthesiologists inhibit this protein receptor by depolarizing the cell with the anesthesia, which then results in the protein receptor not completing its task. Anesthesia depolarizes the cell inducing the cell with a net positive charge.  (Gambulos)

NMDA receptor

Picture 2: NMDA Receptor

The Ca2+ and Na+ enter the cell and induce a net increase of 3+. The anesthesias, which are involved, are Xenon, Ketamine (C13H16ClNO), and nitrous oxide (N2O). (Gambulos)

Anesthesias are really useful in putting you to “sleep”, but once surgery is over and you wake up you don’t want these chemicals to linger around in your body.This diagram shows how propofol (C12H18O) interacts with your metabolism in order to exit the human body.

Propofol and your metabolism

Picture 3: Propofol exiting the body

The propofol interacts with the liver glucuronate and sulfate conjugation. Then is excreted into the urine to exit the body. Usually 70% of the propofol is gone in 24 hours, and about 90% is gone in 5 days.

Before I started this blog assignment I thought anesthesia was the “simple” part of surgery. After doing all this research I have realized that the anesthesiologists must consider many things before using an anesthesia.  For example, if the anesthesia will interact correctly with the patients protein receptors. The anesthesiologist’s job doesn’t stop there, while the patient is “under” they must ensure that they are ready to deal with any side affects that might occur from the anesthesia, and after surgery is complete the anesthesiologist must then ensure that the anesthesia administered must exit the human body safely.

In conclusion, general anesthesia is safe. The side effects are all dealt with appropriately. For example, the hypothermia is dealt with warm anesthesia pumped through your veins. After examining the way anesthesia works, obstructing the function of protein receptors, I have realized that drugs work the same way. The reason why drugs are so dangerous is because often it is difficult to stay within the therapeutic window. Anesthesiologist deals with this by constantly staying by your side, ensuring that the drugs in your system do not exceed the toxic level or go under the therapeutic level. Finally the last part of anesthesia is the way it exits your body. Your body does this through a reaction of the anesthetics with your liver glucuronate and sulfate conjugation. Then the anesthetic proceeds to your urine. At first I thought this was dangerous, but then I remembered that almost every adult drinks alcohol, and 90% of the ethanol, from alcohol, is broken down by your liver. Therefore I concluded that the way anesthesia leaves your body is not so dangerous after all.

References

Garcia, Paul, Scott Kolesky, and Andrew Jenkins. “General Anesthetic Actions on GABAA Receptors .” PMC. Bentham Science Publishers, n.d. Web. 25 Mar 2013. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2866459/>.

Gambulos, Rachel. N.p., 20 04 2008. Web. 25 Mar 2013.

Gordon, G. (2010, August 31). Propofol-3. Retrieved from http://www.anesthesiawiki.net/metrohealthanesthesia/MHAnes/edu/ivanes/propofol3.htm

Lundbeck Institute. (n.d.). Nmda receptor, showing different subtypes. Retrieved from http://www.cnsforum.com/imagebank/item/hrl_rcpt_sys_NMDA/default.aspx

Oda, Yutaka. Hamoka, N. Hiroi, T., Imaoka, S., Hase, I., Tanaka K., Funae Y., Involvement of Human Liver Cytochrome P4502B6 in the metabolism of Propofol. The British Journal of Pharmacology. 51. 281-285. 2001.

Thomas, Shawn. Drug Reference for FDA Approved General Anesthetics @ Neurotransmitter.net. 2007.

Want to be beautiful? Get a Botox… But is it safe?

Encyclopædia Britannica Image Quest
Encyclopædia Britannica Image Quest

It was not long ago that I reached news that cosmetics were one of the major economic markets in South Korea. Apparently, there are increasing numbers of people who wants to get a surgery in South Korea. Then, some days later I’ve gotten the news, a Chinese travel agency advertisement caught my eyes. The advertisement showed a “Cosmetics Travel to Korea” and I thought that cosmetics are one of the most important elements of human life. Therefore, I thought of investigating the role of chemistry behind the cosmetics.

People want to become pretty, but the genetics always hinders their wants. As the human civilization entered the 21-century, cosmetics became more important. The cosmetics have developed throughout, and now humans can change their appearance without any physical surgeries. It is the invention of Botox.

Well then why Botox out of all of the cosmetic goods? That is because, Botox is the most common and has some history, and it has been commonly used and popular.

According to http://navercast.naver.com Botox is mainly consisting of botulinum toxin, and this botulinum toxin is a form of a protein that is connected with disulfide. During this process, every 50 kilodaltons of protein mixes with every 100 kilodaltons of disulfide and create botulinum toxin. However, most of the times, bacteria produce this substance. A bacteria called Clostridium botulinum when entered into human body, stays into the intestines of humans and produces this toxin and most of the time causes botulism. The function of the botulinum toxin is basically hinders the neurotransmission of muscle contraction, so that muscle contraction does not occur and eventually the muscle gets paralyzed.

Now there is a chemistry part in this substance called botulinum toxin. “The toxin, a zinc proteinase, acts by preventing the release of the neurotransmitter acetylcholine from vesicles at the neuromuscular junction. As a proteinase, the toxin cleaves one or more of the fusion proteins by which the vesicles release acetylcholine. In the absence of acetylcholine, contraction of the muscle–or in some cases, the activity of a gland–is temporarily inhibited.” (Ember, 2005). This is an actual chemical process that creates the effect. To sum up, botulinum toxins prevent acetylcholine, CH3COOCH2CH2N+(CH3)3).

Encyclopædia Britannica Image Quest, Botulinum toxin molecule
Encyclopædia Britannica Image Quest, Botulinum toxin molecule

Now the fearful part of botox and botulium toxin is that 12 to 16 nano grams of botulium toxin can kill a man of 60 kilograms. Therefore, if you think about it, you can kill basically all the human beings on earth with only 130 grams of botulinum toxin. Because of this trait of Botox, it was once tried to develop as a bio-chemical weapon during World War II.

However, today its uses are beneficial. It is used to cure crossed-eyes, excessive sweating, muscle convulsion (widely known as muscle cramp), some Parkinson’s disease, and etc… And most importantly, in cosmetic Botox is widely used. Moreover, as I know its danger of killing humans, I researched how much does every dose of Botox does it usually contain. In a bottle of Botox, it contains 100U and in every each one shot of Botox on human’s face does not exceed 100U. Moreover, for it to kill a human being, it needs 2800 to 3500 U of Botox. Therefore, in this 100U, contains about 0.4 to 0.6 of botulium toxin. However, it is not still 100% safe to use Botox. Benefits of using Botox overwhelms the risk of using Botox, so it is right to be used, but it still needs careful supervision that if someone uses more than 100U.

Bibliography

Yeo In Hyung (2012.03.19). Botox. General format. Retrieved from http://navercast.naver.com/contents.nhn?rid=44&contents_id=7614&leafId=44

Lois Ember (2005.06.20). Botox. Retrieved from http://pubs.acs.org/cen/coverstory/83/8325/8325botox.html

Botulinum Toxin A, Molecular Model. [Photograph]. Retrieved from Encyclopædia Britannica Image Quest. http://quest.eb.com/images/132_1189041

Medical Equipment. [Photography]. Retrieved from Encyclopædia Britannica Image Quest. http://quest.eb.com/images/132_1259640

Talking like Bacteria

I was searching for a topic to discuss in my blog post, when I found a video of Ted Talks concerning the cell-to-cell communication in bacteria. I’d found this episode particularly interesting because I’d learned in biology class that bacteria are very simple, unicellular organisms that carry out only the basic homeostatic procedures so they can divide and multiply into identical clones of themselves; but apparently, they’re a bit more complicated.

Bonnie Bassler, director of Graduate Studies in the Department of Molecular Biology, had one question for her lab at Princeton University: how can bacterial cells affect their environment so greatly despite their microscopic size and seemingly monotonous solitary existence. Their answer came from a harmless marine bacterium called Vibrio fischeri that makes bioluminescence light only when surrounded by a number of identical cells and not in dilute suspensions. She discovered that bacteria secreted small molecules known as autoinducers that when the bacteria were alone, floated away, signaling the cell to make no light; however, when this bacteria was found in high density, the small molecules increased in proportion to cell number and when it passed a certain threshold, all the cells in the community took note of the concentration and turned on their bioluminescence in synchrony.

Screen shot 2011-11-15 at 6.57.35 PM

This process is known as quorum sensing and allows bacteria to count their numbers, determine when they have reached a critical concentration, and then change their behavior in unison to carry out certain functions that are only successful with high numbers of the bacteria. Although it was first believed that only a few marine bacteria could carry out this communication technique, Bassler proved it to be more than an anomaly. All bacteria cells have a protein that produces this signaling molecule and consequently, a signal receptor protein (similar to the lock-and-key receptors on the membranes of our cells). Once these autoinducers have reached a certain density, they lock on to the receptor proteins and activate the group behavior genes. Of course, since there is always more than one species of bacteria in any given environment, each cell has both intra-species communication (with each different species having their own specific autoinducer) and inter-species communication (with a generic signal used by every bacteria).

Screen shot 2011-11-15 at 7.07.35 PM

Quorum sensing is used by bacteria to overcome large hosts; they wait, secreting their signal molecules, until their number increases and are strong enough to fight off the larger organism’s immune system. Realizing the importance of the bacteria’s communication system can help find new ways in fighting infections caused by bacteria resistant to current antibiotics (which are growing in number every year). New vaccines that blocked quorum sensing would prevent the shift from harmless to virulent and allow the body’s own immune system to combat the bacteria. (Unfortunately, they would not be an effective treatment against infections that had already progressed.)

Professor Kim Janda, director of the Worm Institute for Research and Medicine at Scripps Research, successfully designed a molecule that induced the production of a certain type of antibody in rats infected with Staphylococcus aureus (a drug-resistant staph “superbug”) that bound to and sequestered the targeted autoinducer, effectively blocking quorum sensing and infection in the mice. Janda believes similar anti-quorum sensing molecules could have a great impact when given to humans as a passive vaccine.

The implications that accompany this discovery is that we can take organisms much smaller and older than our species and yet apply them to other seemingly very different organisms. Our knowledge of the bacteria’s chemical language allows us to speculate and further expand our understanding of the mechanisms that are underway in multi-cellular organisms such as ourselves. Bassler believes that “ ‘if we can understand the rules or paradigms governing the process in bacteria, what we learn could hold true in higher organisms.’ ”

Works Cited:

Bassler, Bonnie. “Bonnie Bassler on How Bacteria “Talk”” Lecture. Ted Conferences. Feb. 2009. Ted: Ideas Worth Spreading. Ted, Apr. 2009. Web. Apr. 2009.

“HHMI Scientist Bio: Bonnie L. Bassler, Ph.D.” Howard Hughes Medical Institute | Biomedical Research & Science Education (HHMI). Web. 17 Nov. 2011

“News Release: Scripps Research Team Blocks Bacterial Communication System to Prevent Deadly Staph Infections.” The Scripps Research Institute. 30 Oct. 2007. Web. 17 Nov. 2011.

Headaches an IB student’s kryptonite

While thinking about what to do this blog post on, I felt a headache coming on from the recent amount of stress I have been under from being an IB student. As IB and AP students we have all had a tension-headache at least once in our lives. I had horrible headaches last year, my mom took me to a Chinese doctor who made me drink an herbal tea and get acupuncture. But I never really know what exactly a tension headache is. So what is it?

“A tension headache is a generally diffuse, mild to moderate pain that’s often described as feeling like a tight band around your head. A tension headache –or tension-type headache as it medically known- is the most common type of headache, and yet its causes aren’t well understood.”-Mayo Clinic

Tension headaches are the most common type of headaches out of; migraines, cluster headaches, and secondary headaches. “About 69% of men and 88% of women develop a tension headache sometime during their lives

The main symptoms of a tension headache are:

-Dull, aching head pain.

-Sensation of tightness or pressure across your forehead or on the sides and back of your head.

-Tenderness on your scalp, neck, and shoulder muscles.

The headaches can last from 30 minutes to an entire week. If the headaches occur 15 or more times a month for at least 3 months, then the headaches are chronic. If the headaches occur less then 15 times in a month, then the headaches are episodic.

The main triggers for a tension headache are:

-Stress

-Caffeine (to much or withdrawal)

-Depression

-Anxiety

-Fatigue

-Over exertion

-Skipping meals

-Inadequate rest

-Poor posture.

However there are many other types of headaches that are much more serious. There are migraines, which are less common. If a headache is recurrent and disabling to the point of stopping you from carrying on with your everyday life. Migraines are described as pounding or throbbing pain on both or one side of your head. People treat migraines by over-the-counter medication. However if they are really severe, you might need stronger migraine-specific medication that can only be prescribed by a doctor.

The third time of primary headache are cluster headaches. These headaches are excruciatingly painful, causing an intense pain around your eyes. These headaches are rare; they get their name because they happen in clusters for about a month or two at a time, around the same time every year. Regular prescription does not help ease the symptoms but doctors can prescribe treatments to ease the pain.

These headaches are all primary headaches, but there are also secondary headaches. Secondary headaches have a separate cause, like illness, which include headaches that come from drinking too much alcohol or after a head injury. Some headaches can arose from the side effect of taking a medication, also some people get headaches when they are sick; from the flu, cold, or an allergic reaction. Frequent headaches can also be caused from taking too many painkillers. Headaches in women are more often caused by hormones, many women link their headaches with their period. If there’s something seriously wrong, like a brain tumor, the headache will become very horrible, however this is very rare and the cause is almost always something else.

These triggers sound like things I find myself doing, these days I find myself getting little to no sleep, and I am under a tremendous amount of stress from school. Learning about tension headaches is important because many students are suffering from these headaches, so it is important we understand these systems to know what kind of headache we have, if its chronic and very persistent then you should go see a doctor. The doctor will most likely prescribe medicine such as, paracetamol, aspirin, or ibuprofen for you to take.

Bibliography:

“Tension Headache.” Science Daily: News & Articles in Science, Health, Environment & Technology. Web. <http://www.sciencedaily.com/articles/t/tension_headache.htm>.

“Tension Headache (stress Headache), Causes, Symptoms, Diagnosis, and Treatments on MedicineNet.com.” Web. <http://www.medicinenet.com/tension_headache/article.htm>.

Staff, Mayo Clinic. “Tension Headache – MayoClinic.com.” Mayo Clinic. Web. <http://www.mayoclinic.com/health/tension-headache/DS00304>.

“Tension Headache Causes, Symptoms, Treatment – Tension Headache Causes on EMedicineHealth.” Web. <http://www.emedicinehealth.com/tension_headache/page2_em.htm>.

“Headaches – NHS Choices.” NHS Choices – Your Health, Your Choices. Web. <http://www.nhs.uk/conditions/Headache/Pages/Introduction.aspx>.

Green Fluorescent Protein: the Art and the Science

This summer I took a course at Rutgers University in New Jersey called GFP: the Art and the Science. It was taught by a biochemistry professor, Dr. William Ward (who had started his own company, Brighter Ideas Inc., to help others realize the potential of GFP), and supposed to be quite difficult. I gleaned this by the topics we were required to write about to get into the program. A lot of them weren’t things that normal students would know off the top of their heads, and questions often had terms like ‘chromophore’ and ‘cyclic tripeptide’ in them. We were supposed to be investigating GFP, a relatively new protein.

Our task was to use biochemistry purification techniques to purify a crude sample of GFP. Dr. Ward and his assistants had inserted the gene for GFP production into e. coli, produced numerous bacteria colonies and put the colonies in to a blender. The result was a green, cloudy, viscous mixture of dead, disembodied bacteria, DNA, other proteins, and ribosomes, etc. These were referred to as ‘contaminants’. Because we only wanted the GFP this meant that we would have to get rid of everything else, which would be difficult. One of the techniques used was chromatography, which is a method for separating substances based on certain criteria, such as charge, polarity, hydrophobicity, density, size, shape, affinity, and solubility. We used ammonium sulfate precipitation, hydrophobic interaction chromatography (HIC), ion exchange chromatography (IEX), and high pressure liquid chromatography (HPLC) to purify the crude GFP sample. After each round of purification we used a spectrophotometer to measure the purity of our sample. We ended up purifying the crude sample, which was only about 25% GFP, to a sample that was nearly 100% GFP. But how to these purification techniques that we used work? Why are they so effective?

GFP

Nearly pure GFP on a UV light

GFP2

samples of the purest GFP

GFP3

collecting samples of GFP as it elutes from the chromatography column

Ammonium sulfate precipitation is a method used to purify GFP by altering its solubility. It solidifies GFP into a mass that does not easily dissolve in water. Therefore, when the crude GFP sample is centrifuged, the GFP separates from the more soluble contaminants by forming a pellet on the bottom. HIC purifies the sample by resulting in only the molecules that have a similar hydrophobicity. IEX purifies the sample by resulting in only molecules with a similar charge. Hydrophobicity and charge are two important characteristics of GFP. By purifying the crude GFP sample using by using these two criteria, a high level of success was ensured.

However, you may be asking yourself why GFP is important. If scientists are interested in purifying it, this must mean that it is worth isolating for further study or for further applications in real life. GFP is special simply because it glows green when exposed blue light. It first came to the public knowledge when a Japanese organic chemist and marine biologist, Osamu Shimamura, decided to investigate what allowed aequorea victoria jellyfish to glow green. He was the first person to isolate GFP from the jellyfish and find out which “part of GFP was responsible for its fluorescence” (Zimmer, Marc). He, along with Roger Tsien and Martin Chalfie won the Nobel Prize in Chemistry in the year 2008 for the “discovery and development of the green fluorescent protein GFP” (nobelprize.org, 2008), which only demonstrates the level of interest it has created in the scientific community. GFP can be modified for a large number of uses – it has been used to create glowing animals/pets, used as a marker in a cancer cell to track the activity of cancer in certain situations, and used in brains to create fluorescent multicolored neutrons which result in beautiful rainbow pictures of brain activity. It is even possible for GFP to be manipulated to express different colors. However, in order for GFP to be used in this fashion GFP must first be isolated, purified and studied, which is why the success of our purification was so important. Only by purifying it can the true potential of GFP be realized.

Works Cited

  1. “Martin Chalfie – Autobiography”. Nobelprize.org. 24 Jul 2011 http://nobelprize.org/nobel_prizes/chemistry/laureates/2008/chalfie.html
  2. Zimmer, Marc. “Green Fluorescent Protein – GFP History – Osamu Shimomura.” Connecticut College: Home Page. Web. 24 July 2011. <http://www.conncoll.edu/ccacad/zimmer/GFP-ww/shimomura.html>.
  3. Zimmer, Marc. “Green Fluorescent Protein – Cool Uses.” Connecticut College: Home Page. Web. 24 July 2011. < http://www.conncoll.edu/ccacad/zimmer/GFP-ww/cooluses0.html>.

Some pictures:

The rainbow of GFP colors

The rainbow of GFP colors

brainbow1

A “brainbow”

300px-GloFish

glofish – genetically modified pet fish

Image Sources

  1. http://www.conncoll.edu/ccacad/zimmer/GFP-ww/cooluses0.html
  2. google images
  3. Green Fluorescent Protein: Wikipedia.org page

380grams

Eun-Sik Kim

What does 380 grams mean to you? The weight of a cellphone? The weight of a jar of jam? No. To one Korean family, it was the weight of a 25-week old baby, the youngest surviving premature baby in Korean history.  The tiny baby boy Eun-sik, after just 9 months under care at the hospital, went home on April 16, 2011 as a “healthy baby (Kwon)” of 3.6kg.

Because the lungs are the last organs to develop in a human body, this baby’s lungs were not fully developed. So, doctors had to inflate his lungs with pulmonary surfactant, which is a combination of a lipids and proteins that reduces surface tension. Eun-sik had one heart operation and one hernia repair surgery.

What was truly magical about this baby was that it was not the development of some revolutionary medical technology, but the use of current knowledge, effort, and love that saved this baby’s life. Unfortunately the current understanding of “birth timing in humans (NHS)” is limited.

The number of premature births has been increasing lately, and this is becoming a serious issue. Recently researchers at Vanderbilt University, Washington University, and the University of Helsinki announced that they found a gene that was linked to premature births. This research began as scientists believed that there must have been “an evolutionary pressure” to “shift the time of birth (BBC)” to produce a smaller baby. They looked for the DNA that showed evidence of “accelerated evolution (BBC)” and scientists found, located, and compared the gene they found in 328 Finnish mothers, some of who had premature births.

The follicle stimulating hormone receptor gene has shown strong association to pre-term births, but the experiment only took a small pool of applicants, so it is not definite. This gene is involved in the release of an egg from the ovary and the production of the hormone estrogen.

This “evolutionary genetic approach (NHS)” could assist further investigation into premature birth, and may be applied to the study of other diseases, especially ones that have increased in occurrence recently.

Prematurity is the leading cause of neonatal mortality, however the cause of premature birth remains elusive. The cause for about 50% of preterm births is never determined. If women were tested for any Changes in the FSHR gene, we would be able to predict and prepare for the birth of premature babies. The implications of this gene are huge. This would affect infant mortality, and long-term complications of being born prematurely. The risk of premature birth is likely to be a mix of genetic and environmental factors such as the mother’s health and lifestyle. This gene surely will help predict women who are at risk, but there are other factors to consider.

Sources:

Iron Absorption!

At a recent checkup, my doctor informed me that my blood iron levels were once again below the minimum healthy threshold and that I am anemic, even though I had been taking iron pills for almost a year. The doctor said that this was a serious problem, as iron is essential in the successful completion of many vital body functions, notably the production of hemoglobin, which is responsible for carrying oxygen throughout the bloodstream

Needless to say, I was pretty worried. The doctor then proceeded to tell me that my problem with iron absorption might as simple as that I was eating too much of certain foods that are known to block iron absorption, and that I would need to limit the amount of those foods that I ate. He also told me to increase my intake of foods that would facilitate and “enhance” iron absorption, helping my iron levels return to normal.

So what are these “blocking” and “enhancing” foods?

It is first necessary to look at how iron is absorbed into the body. Iron absorption occurs at a place called the duodenum (Does Vitamin C Increase Absorption?). The duodenum is the first section of the small intestine.

duodenum_position

It can be assumed that the duodenum would simply absorb all the available iron in any food that passed through it, and then send the remaining “waste” material on through the digestive system.

This is not so. There are two types of iron that are present in food, heme iron and non-heme iron.

Heme iron is present in meat, and the duodenum absorbs it very well. It is absorbed well because it it is composed of animal hemoglobin and muscle tissue, which is similar in structure to our own bodies, and is also what the body is trying to produce with the iron absorbed (Does Vitamin C Increase Absorption?)

On the other hand, non-heme iron is found in all non-meat food products, such as dark green leafy vegetables. This form of iron is quite difficult for the duodenum to absorb (Non Heme Iron Foods), and only about 1-7% of non-heme iron in a food source is absorbed. This results in extremely little iron being absorbed at all, potentially leading to low iron levels and health problems (like anemia, where there is not enough hemoglobin in blood to carry oxygen, resulting in dizziness, fatigue, and fainting) (Dietary Supplement Fact Sheet: Iron), even though a person might be eating foods that are technically “high in iron”.

But can this low absorption rate be affected by anything else?

Unfortunately, I learned from my doctor that the consumption of a very common food can even further reduce the amount of iron absorbed by the duodenum: tea.

Tea contains chemical compounds called polyphenols (Foods That Block Iron Absorption) They bind to the non-heme iron before and renders it difficult to be absorbed by the duodenum.

However, I also learned that there is also a food that facilitates the absorption of non-heme iron: anything citrus (my doctor recommended orange juice, or just orange)! Citrus fruits contains vitamin C, which is ascorbic acid.

cid_235

When the ascorbic acid bonds with the non-heme iron, the compound, as a whole, becomes more stable, and the entire molecule becomes water soluble (Does Vitamin C Increase Absorption?). The membranes in our body all allow water to pass through.  As the iron has become water soluble, the duodenum’s mucus membrane readily absorbs the dissolved iron and much more iron is delivered into the bloodstream to produce hemoglobin.

Having learned all of this, I, an orange hater, thought to myself “Well why doesn’t everyone who has iron deficiency problems just eat lots of meat then?” I immediately realized that this was a huge bias.

This new knowledge was certainly beneficial for me, but would be even more beneficial to groups of people who do not consume meat because of religious or personal reasons, such as Buddhists or vegetarians.

Although eating meat is certainly not essential to survival, hemoglobin is. As these groups of people do not consume meat, they lose all sources of the easily absorbed heme iron. Thus, it is necessary that they are aware of these “blocking” and “enhancing” foods in order to be healthy.

Also, going back to the beginning of the post, the doctor made a point to tell me that it likely wasn’t any serious medical condition that was causing my anemia, simply a bad combination of food and that the chemistry between the foods was what was to blame. This shows that although medicine is widely considered to be rooting in biology, understanding how to diagnose and cure illnesses requires chemical knowledge as well.

Bibliography

“cid_235.png.” ascorbic acid. Web. 28 Mar 2011. <http://sci-toys.com/scichem/cid_images/cid_235.png>

Davis, Sarah. “Non Heme Iron Foods.” Livestrong. Livestrong, 23 March 2010. Web. 28 Mar 2011. <http://www.livestrong.com/article/87179-non-heme-iron-foods/>.

“Dietary Supplement Fact Sheet: Iron.” Office of Dietary Supplements. National Institutes of Health, n.d. Web. 28 Mar 2011. <http://ods.od.nih.gov/factsheets/iron/>.

“duodenum_position.png.” Duodenum Anatomy, Location, Parts and Pictures. Web. 28 Mar 2011. <http://www.healthhype.com/duodenum-anatomy-location-parts-and-pictures.html>.

Keefer, Amber. “Foods That Block Iron Absorption.” Livestrong. Livestrong, 9 November 2009. Web. 28 Mar 2011. <http://www.livestrong.com/article/32697-foods-block-iron-absorption/>.

McCarty, Kristen. “Does Vitamin C Increase Iron Absorption?.” Livestrong. Livestrong, 5 August 2010. Web. 28 Mar 2011. <http://www.livestrong.com/article/195055-does-vitamin-c-increase-iron-absorption/>.

Crystal Technology

When I was a kid, I was fascinated with science. Though my parents never tired of answering my questions, eventually they bought me books that offered more comprehensive explanations and scientific experiment kits so I could make my own discoveries. My favorite activity was crystal growing. I loved to watch a dish of concentrated crystal solution and a seed crystal become something beautiful. Each day the crystal would grow until the solution ran out. Afterwards, I would play with the crystal and then throw it away. I recently revisited crystals, also known as giant lattices or crystallized solids in IB Chemistry. I realized that the theoretical concepts underlying the structure and physical properties of crystals give them great potential for real life scientific uses, which led me to do additional research on how crystals are being used today.

Crystals are defined scientifically as “a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions”. There are two types of crystals, ionic and covalent, and covalent crystals are further broken down into polar and non-polar molecules. The process of “growing” a crystal is referred to as crystallization or solidification. Although this sounds artificial, it can occur naturally. Quartz crystals exist because of the crystallization of silicon dioxide, and snow exists because of the crystallization of water molecules.

snowflakes snowflake crystals

Crystals can have a variety of uses because of its distinct chemical and physical properties. Ionic crystals have high melting points and are extremely hard and brittle. Molecular crystals are the opposite, with low melting points and are soft. My dad, a physics major, once used existing crystal technology to create commercial products used in laser surgery. He and his colleagues used the crystallization process to make YAG crystal cavities that contained laser knives during surgery. (YAG stands for yttrium aluminum garnet, a synthetic crystalline mineral with the chemical formula Y3Al5O12.) He told me that the hardness, consistency and high melting points of ionic crystals were perfect for making the cavities, which allow a laser beam from a generator to pass through and create a knife-like beam that performs surgery at a doctor’s discretion. This shows that the science of crystals can be used in the field of medicine.

Another application of crystal technology are LCDs, or liquid crystal displays. Liquid crystals are crystals with characteristics between those of conventional solid crystals and liquid crystals. They “flow like liquid but their molecules are arranged in a crystal-like way”. They are used to make the displays of everything from TVs to PSPs because of their ability to modulate light. Pixels in the screen of your computer are filled with liquid crystals and placed in front of a light source. The liquid crystals function by twisting the light so that it avoids being absorbed by polarizing filters, thus giving the pixels brightness and color. LCDs have become popular in the past few years because they are the healthier alternative to more traditional cathode ray tube (CRT) displays. LCDs contain significantly less lead, lowering consumers’ chances of becoming victims of lead poisoning. These two uses of crystals show how diverse its applications can be.

nintendo-ds

a Nintendo DS, which uses a LCD screen

What this research has taught me is that crystals can also be used in areas of science to help people or improve their quality of life. Like crystals, other science that you learn as a kid have fascinating applications in real life. Hopefully my post will inspire you to do research on a favorite childhood scientific experiment, or make a connection between theoretical concepts and a real life application, like I did.

600 words (not including image captions)

Sources:

Information

  • “Crystal.” Wikipedia.org. Wikipedia, 07/10/2010. Web. 10 Oct 2010. <http://en.wikipedia.org/wiki/Crystal>.
  • Green, MD, Nicole. “Lead Poisoning.” KidsHealth. kidshealth.org, Oct 2009. Web. 9 Jan 2011. <http://kidshealth.org/parent/medical/brain/lead_poisoning.html>.
  • Helmenstine PhD., Anna Marie. “Snowflake Chemistry.” About.com. About.com, 2011. Web. 9 Jan 2011. <http://chemistry.about.com/od/moleculescompounds/a/snowflake.htm>.
  • “History and Properties of Liquid Crystals .”Nobelprize.org. About.com, 2011. Web. 9 Jan 2011. <http://nobelprize.org/educational/physics/liquid_crystals/history/>.
  • Hung, Acta Chir. “Use of laser knife in thoracic surgery.” PubMed.gov. PubMed.gov, 1989. Web. 10 Oct 2010. <http://www.ncbi.nlm.nih.gov/pubmed/2718679>
  • “Liquid crystal display.” Wikipedia.org. Wikipedia, 09/10/2010. Web. 10 Oct 2010. <http://en.wikipedia.org/wiki/Liquid_crystal_display>.
  • “ND:YAG Crystal (Neodimium Doped Yttrium Aluminum Garnet).” Red Optronics. Red Optronics, 2010. Web. 9 Jan 2011. <http://www.redoptronics.com/Nd-YAG-crystal.html>.
  • United States. Lead Exposure in Adults – A Guide for Health Care Providers. , 2008. Web. 9 Jan 2011. <http://www.health.state.ny.us/publications/2584/>.

Images

  • “Nintendo Ds.” 1up.com. Web. 10 Oct 2010. <http://www.1up.com/boards/posts/list/45822.page?escapeContext#1798424>.
  • “Snowflake crystals.” Web. 9 Jan 2011. <http://astheclevercrowflies.blogspot.com/2005_12_01_archive.html>.

Will drinking alcohol keep you warm?

Drinking Alcohol

Will drinking alcohol warm your body up? Well, technically yes AND no. Many people believe that drinking alcohol will keep their bodies warm. I was one of the “people” who believed this before my research. Few days ago, my teacher said that drinking alcohol would not help you survive in colder regions. Therefore I wanted to find out myself whether what I knew was right or wrong. According to Michaele Dunlap, Psy.D, when a person consumes alcohol it deteriorates the central nervous system including intellectual functioning and sensory control. Also Craig Freudenrich, Ph.D.states that the alcohol later influences the medulla, which controls most of the functions in a body including temperature. Once the sensory control is deteriorated, a slight paralysis occurs with the nervous system that controls the dilation of blood vessels. This nervous system is called the autonomic nervous system.

Autnomic Nervous System
Autnomic Nervous System

Because of this failure to control dilation, blood vessels become closer to the skin then usual. As a result of this vasodilation, the blood vessels conduct more heat on the skin and therefore increase the “body” temperature. Technically, one may say that drinking alcohol does increase the body temperature but how about the interior of the body? According to Dr. Willian G. Haynes, however, “Consumption of alcohol undoes many of the human body’s healthy reflexes, one of which is keeping the core body temperature warm in cold weather,” When we are cold, it is mainly because the blood vessels move towards the organs to keep the core body temperature warm. By drinking alcohol, however, the blood vessels no longer maintain the core body temperature. As a result the core temperature would actually decrease when alcohol is consumed. This was proven by The Advanced Research Center of Human Sciences in the University of Waseda. They conducted a research in which same amount of alcohol with equal concentration was given to the test subjects and recorded the affects on the temperature. In the end, the subjects core temperature decreased by 0.3C. Also, their experiment proved that this decrease in core temperature was not only because of the skin vasodilation but also the behavior of the subject.  In conclusion although alcohol increases the temperature at periphery of the body, the essential core temperature decreases due to the person’s behavior and the skin vasodilation. If 50% of the world’s population hold this misconception that alcohol will keep you warm, 50% of the world would face the danger of making the

Hypothermia
Hypothermia

wrong decision. When alcohol is consumed during the cold season, the person could encounter the danger of hypothermia,which is caused around 33-77% by alcohol consumption, and even death. That is why it is important for people to know about this. Just by correcting the misconception, death could be prevented.

Work Cited

“Effects of alcohol on thermoregulation during mild heat exposure in humans. .” Advanced Research Center for Human Sciences (2005): n. pag. Web. 4 Nov 2010. <http://www.ncbi.nlm.nih.gov/pubmed/16377461>

Freudenrich, Craig. “How alcohol works.” How Stuff works n. pag. Web. 1 Nov 2010. <http://health.howstuffworks.com/wellness/drugs-alcohol/alcohol10.htm>.

G. Haynes, Wiliam. “Effects of alcohol in the cold.” University of Iowa November 2000: n. pag. Web. 1 Nov 2010. <http://www.uihealthcare.com/topics/medicaldepartments/pharmacy/alcoholandcold/index.html>

“Hypothermia.” Wikepedia n. pag. Web. 1 Nov 2010. <http://en.wikipedia.org/wiki/Hypothermia#Alcohol>.

P. Dunlap, Michaele. “Biological Impacts Of Alcohol Use: An Overview.” Oregon Counseling n. pag. Web. 1 Nov 2010. <http://www.oregoncounseling.org/ArticlesPapers/Documents/ETOHBIOFx.htm>