ChemSemBlog

Our guest speaker for the chemistry seminar held on November 12 was Jeffrey Turk, who is currently an assistant professor of chemistry at Alma College. His research includes medicinal or drug-related chemistry and fragrance chemistry. The topic of his presentation was mainly Sandalwood aroma compounds. During the presentation, Dr. Turk did a great job at setting up the background and foundation about olfactory system and presenting his research project about fragrance molecules of Sandalwood, so that I could overall understand and easily follow what he talked about.

Most of all, because I had a chance to smell some compounds he brought, I was so excited. Interestingly some samples had very good odors, but others didn’t. In addition, one thing I was interested in was that the molecules which were stereoisomers each had different odors depending on their S or R configuration.

Also, I learned a lot about fragrance molecules from his talk. He said that odor molecules, less than 300g/mol, are generally detectable and volatile. To be detected, at first, the molecules should bind to olfactory receptors, such as G protein coupled receptor (GPCR). Surprisingly more than 400 genes are coded for different olfactory receptors.

I also learned that the fragrance molecules of Sandalwood for his research were synthesized via Allene-Claisen rearrangement. One of the significant goals of his research was to produce these aromatic compounds with atom-efficient reaction to reduce wastes. In the fragrance industry his research works were very important because he could synthesize fragrance molecules which were nature identical or similar with much less cost.

For my non-science friend, I would say that organic chemistry plays an important role in fragrance industry to synthesize compounds that smell good.

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Our presentation last Thursday was brought to us by Jeffery A Turk, assistant professor of Chemistry at Amherst College. His presentation was about Sandalwood and the need for making synthetic fragrance molecules for the benefit of saving on natural resources, expanding the palette for fragrance companies, and greater biodegradability, functionality, and sustainability of current molecules being used.  I liked Turk’s style of teaching; he used many different  media (black board, props, PowerPoint) to help us understand his presentation. He was very engaging, often asking questions and making jokes. But what I was most impressed about with his presentation was how well he knows his slides. Once or twice he would skip to the next slide without even looking and begin explaining what was on it!

Turk began his presentation with an overview of how smell works in our body. He thoroughly covered the works of the olfactory bulb and how we perceive what we smell through messages sent to the hypothalamus. I had never really sat down to think about how I smell, but it was very interesting to find out that it is a combination of functional groups like aldehydes, ketones, esters, etc. that our body is interpreting as a specific smell. Another concept that I learned was the Odor Threshold (OT). The OT is the smallest quantity of molecule needed to activate the receptor cells and thus relay smell to the brain. And finally, but certainly not the last thing I learned, I was fascinated by his short comment on a connection from the hypothalamus to the Limbic area of the brain signifying that you feel something when you smell!

The only questions I have are 1. With such a high demand for atom efficient reactions to create sandalwood, is there a high demand for chemists in this field? 2. In a society interested in multifunctionality, in what other areas of science and technology do you see fragrance chemistry affecting in the next 20 years,? and finally 3. Have you marketed any of your own fragrances to companies?

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Our weekly blog posts of seminar presentations have really helped me appreciate the value of science writing and the gift that these writers have. With a topic so close to home, I believe it is safe to say that everyone was looking forward and interested in the presentation brought to us by Jyllian Kemsley on Science Writing.  Broadcasting from California, Kemsley, an associate editor at Chemical and Engineering News, gave her presentation via web cam, a first for us and herself.  The presentation went very well; looking back, it is definitely one of the most memorable for me over the course of the semester.

Kemsley really gave us an insider’s perspective on what it’s like to be a science writer. I was fairly surprised when she told us that a bachelors of Science degree and a two year master’s degree of science writing is all it takes to become a writer. This was definitely something new to me, I previously thought that most science writers needed a doctorate to be a credible source, but in reality the organization publishing the article suffices as credible to the public.  Once a person becomes certified there are many areas of work available, they are hired by newspapers, TV New networks, science Journals, science focused websites, hospitals, government agencies, education institutes, etc.  I hadn’t realized how many different areas of the work force require people capable of interpreting science and being able to relate it in publications to the average person.  Of this partial list of jobs opportunities, the one that stood out the most to me, were the TV news networks.  I was shocked to find out that CNN had recently laid off 18 of its science writers, not because of the layoffs, but because they had so many working for them!  One other thing that I learned (although I could go on forever) was the short amount of time articles are written, edited, and published,  demanding that writers are creative at all times and allowing no room for mental blocks.

Towards the end of the presentation Kemsley told us the personal rewards gained and challenges faced in a career of science writing. She told us what good qualities make up the best science writers and finally gave us a detailed analysis of a typical week lived by a writer. A couple of questions I do have are 1. How reliable is a job in science writing going to be in the future? 2. Can you specialize in school after receiving your two-year master’s degree? 3. And finally what was your favorite story to cover?  All in all I believe this was the most informative presentation and really appreciate the time given by Kemsley.

Thanks again Dr. Kemsley for sharing your time and work with us!

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This week’s speaker was Jeffery A. Turk, an organic chemist who previously worked as a research scientist at International Flavors and Fragrances creating new aroma and chemicals. He spoke of design, synthesis and evaluation of novel enzyme inhibitors and fragrance molecules. I found his presentation style understandable but also quick. Turk was able to explain his work well and he made his presentation come alive by bringing samples of some fragrances.

The first thing that was mentioned which was new to me, was the fact that there are about fifty million olfactory receptor cells, and seven -transmembrane G-protein coupled receptors. The olfactory molecules contact the top of the protein receptors, and the olfactory receptors are tuned to chemical functionality, not odor properties. So when we smell certain odors it is due to certain molecules binding to certain olfactory receptors.

Other interesting facts included were that four hundred genes could code for a single olfactory receptor. There is also a link to the hypothalamus, in which went one smells something there is a part of the brain that lights up known as the olfactory bulb. One can also determine from OT, olfactory trackers, the amount of the molecule needed so that it can be picked up by the olfactory receptor. Since most fragrances come from trees, Turk is working to find other bases such as sandalwood and other new ingredients for which a variety of fragrances can be made. Turk’s goal is to find the reaction in which there is high atom efficiency with little waste and maximum yields. Some reactions that were tried were done with claisen rearrangement. I found the presentation very informative and liked that I was able to test out some of the fragrances made such as Ambrox and Carvone. What I found interesting about Carvone was that it had R and S enantiomers smelling of cinnamon and spearmint.

Many students seemed to enjoy this presentation and were very involved. During the end, Turk answered many questions very well. Although the presentation was appealing, I wasn’t exactly encouraged to do a seminar on this topic, it would be a good project to research on though. I was neither encouraged or discouraged to attend the speaker’s school for graduate studies, but this presentation about how we smell and how some of these molecules used in fragrances were synthesized, made me look at different fragrances in a new way.

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This week’s seminar was done by Dr. Jeffery Turk, chemistry professor at  Alma College.  His presentation was about sandalwood and is aroma.  First, Dr. Turk spoke about olfaction, which is the sense of smell.  Odor molecules bind to receptor cells, located on the cilia inside the nose.  Odor molecules need to be volatile, that is, have a vapor pressure, and they need to be somewhat hydrophobic.  Odor molecules are very small, usually weighing less than 300 grams per mole.  Approximately 400 genes code for olfactory receptors.  The study of olfaction is complicated by the fact that an odorant can bind to multiple receptors, and receptors can accept more than one type of odorant.  The binding of odorants to receptors is based on functional groups.

Dr. Turk then went on to speak specifically about Sandalwood. Sandalwood is a hunted tree, and what is unique about this tree is that the oil from each tree respectively has a different aroma depending on the region of the world that it is located in.  Sandalwood trees are so valuable that companies place barbed wire and guards armed with machine guns around the trees, to protect them from thieves or armed tree harvesters.  After describing Sandalwood, Dr. Turk also talked about the fragrance industry and his prior work as a fragrance chemist, and how it has helped him with his current research. Through this information, I was able to learn more about the difference between natural oils, nature identical, and synthetic.

Overall, Dr. Turk did an impressive job of explaining a topic that most people take for granted every day, in a more in depth and interesting manner such that it brought to light new and valuable information I hadn’t previously know.  Dr. Turk’s style of presenting was very good because his humor made me interested in the information he was sharing.  In the future I hope to hear more seminar’s that are of the same quality as Dr. Turk.

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