Genetic Variation of Taste Receptors

Genetic Variation of Taste Receptors Abstract: The people have different behaviour to choose the food, and there are many factors that affect the food choices. The best significant factor to choose the food is taste. Differences in taste perception of several taste modalities are associated to difference in the taste receptors. Polymorphisms of the genes that encoding these taste receptors may clarify these unpredictability in taste perception. Individual changes in the capability to identify bitter tasting compounds, such as phenylthiocarbamide (PTC) was a well-known example of this variability. This difference divided the people in two groups: tasters and non-tasters, and is because of in part to single nucleotide polymorphisms (SNP) of a bitter taste receptor gene, taste receptor, type 2 (TAS2R) 38. The experiment was designed to determine the PTC phenotype and genotype, the SNP at position 785 is of particular importance in genotyping. DNA was extracted from check cell by using Chelex technique and genotyped by using polymera se chain reaction (PCR) followed by restriction fragments length polymorphism (PCR-RFLP). A 2% of Agarose gel electrophoresed and stained with Ethidium Bromide to imagine the genotype pattern. The class was tasted PTC test paper to compare phenotype and genotype. The total was 108 students the genotype showed 21 taster (+/+), 51 was mild taster (+/-) and 36 was nontaster (-/-). The allele frequency was not statistically significantly differ from European population. Therefore, TAS2R38 genotype is a truer estimation of the extent of the influence of this single gene on taste perception of PTC in a genetically diverse population. Introduction: Taste perception is the most sensitive predictor of how much a food is pleasant and unpleasant. The people are different in the taste perception of sweet, bitter, sour, or salty tastes which could influence the dietary behaviour (2, 3, 4). The variations in the taste perception between the individuals may relate to a variation in the gene taste receptors (2). The gene family of the taste receptors are encoding from TAS1R and TAS2R. The bitter taste receptors are include the TAS2R38 and TAS2R550. While the umami and sweet taste receptors is the TAS1R. The sour taste receptors are the PKDIL3 and PKD2L1. The genetic variation in these receptors may causes to deferential favourites for some types of food. Phenylthiocarbamide (PTC) compounds is the example was more studied in the variation of the sensitivity of taste as the bitterness (2, 5). The TAS2R38 gene is one of the most studied from over twenty-five in bitter taste receptor gene (4).The TAS2R38 gene is responsible for the taste perception of PTC as more bitter and the other related compounds like 6-n-propylthiouracil (PROP) which both contain a group of thiourea (7.8). The variation in the gene TAS2R38 divided the individuals in two groups of thiourea tasters: tasters and non-tasters (4, 5). Phenylthiocarbamide (PTC) The variation in the taste perception of PTC rely on the genetic studies. In 1930s, difference in the ability to taste PTC was first finding by Arthur L. Fox in a laboratory accidental (6). When he was working in the laboratory and transferring PTC powder into a bottle. Some particles of PTC powder flew into the air and his colleague close to him C. R. Noller tasted the particles as bitter but Fox tasted nothing. Fox was make experiment to test a large number of individuals and he found the difference in their ability to taste PTC and he divided the people in two main groups’ tasters and non-tasters (1). Worldwide about 25% of population classified as ‘non-tasters’ and the remaining 75% as ‘tasters’ (1). In addition, Bartoshuk et al, in 1992, discovered that the ‘tasters’ varied in the perception of PTC/PROP in a bi-modal fashion, and they separated them into medium tasters and supertasters. The supertasters were very sensitive to PTC, pe rceiving them as more bitter, while the medium tasters may taste PTC and found it mild bitter. Besides, the spread of super, medium and non-tasters in the general population is roughly 25%, 50% and 25%, respectively (1). The PTC sensitivity believed to be inherited as a simple Mendelian trait with two alleles a dominant trait (T) for taster and recessive trait (t) for non-taster (9). Figure 1: shows the inheritance of PTC trait. PTC genotype TAS2R38 or PTC gene is located on chromosome 7q and consists of a single coding exon 1002 bp long, encoding 333 amino acids, 7-transmembrane domain G-protein-coupled receptor (2, 6). A number of SNPs have been identified within this gene, the three most common SNPs (>1% of the population has variants at a specific DNA sequence, considered an SNP and (4).Also, the PAV/PAV homozygotes are sensitive to PTC more than PAV/AVI heterozygotes while AVI/AVI homozygotes are fewer sensitive (4). The AVI haplotypes in the non-tester differ at 3 SNPs from the PAV haplotypes of the tasters (9). The aim of this practical: To focus on the TAS2R38 genotype and its link with the ability to taste PTC test paper. The SNP at position 785 is of specific concern in genotyping. Comparing the allele frequency detected in the class with those observed in European population subject in group 226 and Sub-Saharan African subject in group 224. Material and Methods: To determine the TAS2R38 (A262V) genotype by using the polymerase chain reaction (PCR) and restriction endonuclease digestion, Fnu4H1 enzyme. The procedure that has been done was as the following: Protocol of DNA Extraction from Cheek Cell (scrape or wash): First week take a 10 ml of water pour into mouth and swirl to release buccal cells and spit back contents into tube. Centrifuge the tube at 3000rpm for 3 minutes, carefully pour off supernatant and retain cell pellet. Added 350Â µl of 5% Chelex mix and then transfer the pelleted buccal cells to new (1.5ml) Eppendorf tube. The 5% Chelex to protects DNA breakdown under a high temperature. Added 4Â µl of proteinase K to the Eppendorf tube that contains buccal cells and 5% Chelex. Incubated the tube containing chelex/cells at 56Â °C for 30 minutes in the heating block, then briefly vortex the tube for 10 seconds after that centrifuge the tube at 3000rpm for 20 seconds. Incubated the tube ( chelex/cells) again in heating block at 98Â °C for 15 minutes, then vortex the tube for 10 seconds, after that centrifuge for 3minutes.Transferred the supernatant that above the chelex containing the buccal cell (DNA template) into the sterile 1.5ml Eppendorf tube and measured the DNA concentration by take 1Â µl of DNA into machine called nanodrop nucleic acid then kept at -20Â °C to preserve the DNA. Protocol of Phenyl Thiocarbanate(PTC) using PCR Reaction: Second week take a 43.5Â µl of master mix was already prepared in the PCR tube and transferred 6.5Â µl of DNA extraction. (Buccal cell DNA).Vortex and spin the tube to make the liquid contents to bottom of the tube. The total PCR tube reaction volume contain 50Â µl of mixtures were placed in the PCR machine and the thermal cycler conditions were: cycle of 94Â °C for 4 minutes. The 40 cycles of 55Â °C for 40 seconds, 72Â °C for 40 seconds and 94Â °C for 40 seconds .Then 1 cycle of 55Â °C for 5 minutes and at 72Â °C for 5 minutes. The sequence of Forward primer was 5’ AACTGGCAGAATAAAGATCTCAATTTAT3’ The sequence of the Reverse primer was 5’ AACACAAACCATCACCCCTATTTT 3’. Restriction Digestion (Fnu4HI): Last week transferred a 20 ÃŽ ¼l of the component mixture (PCR product) to a tube containing 10ÃŽ ¼l of the restriction endonuclease master. The tube was placed in into a 37Â °C heating block for two hours. Electrophoresis of PCR Products: A 30ml of 2% Agarose gel with 0.5Â µl/ml of ethidium bromide was loaded into the gel tank with adjusting the comb, the gel was kept 15 minutes to get stuck. After that the TBE buffer was loaded, covering the surface of the gel and the comb was removed. Take 12Â µl of PCR product undigested and digested into two different tubes added 3Â µl of DNA loading buffer mix and spin. Then, 10ÃŽ ¼l of PCR product/loading buffer was loaded into the well of 2% Agarose gel and 10ÃŽ ¼l of the ladder (100bp) was added in the last well. The gel electrophoresed at 90 volt for 45minutes, negatively charged (-ve) DNA moved toward the anode side (red). Last take gel photograph under UV trans-illumination. Taste tests: The PTC taste test paper was used to observe the capability to identify the bitterness of PTC and its relative with the TAS2R38 genotype. Statistical analysis: The data of the allele frequency for C785 and T785 observed in the class was compared to the allele frequency of European population subjects in group 226 and Sub-Saharan African subject in group 224 by using the Chi square test. The Chi square test was also used to investigate the association between the TAS2R38 genotype and phenotype. All statistical analyses were performed with Minitab data analysis software. References Feeney E. The impact of bitter perception and genotypic variation of TAS2R38 on food choice. Nutrition Bulletin. 2011; 36(1):20-33. Wooding S, Kim U, Bamshad M, Larsen J, Jorde L, Drayna D. Natural Selection and Molecular Evolution in PTC, a Bitter-Taste Receptor Gene. The American Journal of Human Genetics. 2004; 74(4):637-646. Chaudhari N, Roper S. The cell biology of taste. The Journal of Cell Biology. 2010; 191(2):429-429. Feeney E, OBrien S, Scannell A, Markey A, Gibney E. Genetic variation in taste perception: does it have a role in healthy eating? Proc Nutr Soc. 2010; 70(01):135-143. Lalueza-Fox C, Gigli E, de la Rasilla M, Fortea J, Rosas A. Bitter taste perception in Neanderthals through the analysis of the TAS2R38 gene. Biology Letters. 2009; 5(6):809-811. Kim U, Drayna D. Genetics of individual differences in bitter taste perception: lessons from the PTC gene. Clinical Genetics. 2004; 67(4):275-280. Dotson C, Shaw H, Mitchell B, Munger S, Steinle N. Variation in the gene TAS2R38 is associated with the eating behavior disinhibition in Old Order Amish women. Appetite. 2010; 54(1):93-99. Duffy V, Davidson A, Kidd J, Kidd K, Speed W, Pakstis A et al. Bitter Receptor Gene (TAS2R38), 6-n-Propylthiouracil (PROP) Bitterness and Alcohol Intake. Alcoholism: Clinical Experimental Research. 2004; 28(11):1629-1637. Merritt R, Bierwert L, Slatko B, Weiner M, Ingram J, Sciarra K et al. Tasting Phenylthiocarbamide (PTC): A New Integrative Genetics Lab with an Old Flavor. The American Biology Teacher. 2008; 70(5):e23-e28. Appendix

The Analysis of Kaiser and the War by Simon J. Ortiz

Simon J. Ortiz is a Native American who was born on May 27, 1941 in Albuquerque, New Mexico. He belongs to the Acoma Pueblo tribe. He is considered as one of the most respected Native American writer. He grew up in the Acoma village of McCartys and spoke his native tongue of Keresan with his family. Ortiz’s father was a railroad and a wood carver. As a member of the Acoma Pueblo tribe, his father was tasked to preserve the tradition and religious beliefs of the clan (Wiget, 1994, p. 115)Simon J. Ortiz went to the McCartys Day School and then to St. Catherine’s Indian School in Santa Fe, New Mexico. In school, Native Americans were prohibited to speak their native language. Ortiz had a difficult time assimilating with the new culture he was exposed to. He began to write in his diary his experiences and create short stories. He channeled his energy to read books (p.117)While studying away from his family, Ortiz can’t bear his loneliness and returned to his hometown . He enrolled at the Albuquerque Indian School. The school is a vocational school which taught the students plumbing and mechanics. Ortiz learned metal and woodworking. After graduating from Grants High School in Grants, New Mexico, Ortiz worked at Kerr-McGee uranium plant. His experience at the mining plant inspired him to write his work, â€Å"Fight Back: For the Sake of the people, for the Sake of the Land† (p.123)Through an educational grant, Simon J. Ortiz was able to attend Fort Lewis College and he majored in Chemistry (p.125).Simon Ortiz’s Career PathOrtiz served the U.S. Military for three years. Fresh from the army, he enrolled at the University of New Mexico. He pursued his passion for writing and he was able to write his life experiences as a Native American. In 1968, he became a fellow at the University of Iowa. â€Å"In 1982, he was made an editor at the Pueblo of the Acoma Press. In 1988, he was tasked to be an interpreter for the Acoma Pueblo tribe and the following year Ortiz became the First Lieutenant Governor for the clan† (p.130)Throughout the years, Ortiz was recognized and given numerous awards for his literary works. He received the Pushcart prize for his work â€Å"From Sand Creek: Rising in This Heart Which Is Our America†. He was also given the Lifetime Achievement Award for his work â€Å"Returning the Gift† (p.133)Literary ThemesSimon J. Ortiz presented issues common to people particularly the plight of his Acoma Pueblo tribe. His work discusses themes of â€Å"alienation, colonialism, Native American struggles, the environment and the effects of technology† (Native American Literature, 1985, p.178)â€Å"Kaiser and the War†We can not divorce the life of the author from his art because his life experiences have a profound influence on his literary works. A case in point is Simon Ortiz’s short story, Kaiser and the War.The story revolves around a man who had little knowledge of the English language;   Kaiser, the protagonist opposed the idea of being enlisted in the U.S. Military Service. As a result, he escaped to the Black Mesa Mountains while being pursued by the county sheriff and the draft board agents. As I see it, Kaiser avoided the draft because he feels that the war is senseless. Like most Native Americans who mostly lived in their communities,   he does not feel an affinity towards mainstream America. So, why would he go to war? His flight for avoiding the draft is the only way he could free himself from the dictates of the Americansociety. It is a   sense of freeing himself physically and spiritually.. It is also a way of expressing his desire to return to his roots and his essence as a human being.   His escape to some extent provided him the option of dealing with his chaotic life.   However, Kaiser’s escape did not only alienate him even more from the society; it also alienated him from his family. Finally after years of hidi ng, Kaiser surrendered and he was sent to jail for escaping the draft. After serving his time in prison, Kaiser becomes isolated from society. From this experience, Kaiser succumbed to depression. He was unable to keep his life together after what transpired. He failed to reunite with his family. In the end, he lived alone and died a broken man.The themes of alienation and separation surround the story. In the Norton Anthology of American Literature, Nina Baym, â€Å"implies that this theme represents the Native Americans’ struggle†, (Baym, 1997, p.2778). The story also include events that transpired in Ortiz’s life like his childhood experiences in school where he had limited knowledge of the English language and lastly, his enlistment to the U.S. Military. The tale appears to link the past and the present with regards to feelings of alienation and separation (Encyclopedia of American Literature, 1998, p. 858).The Economic, Social and Political Conditions of th e Native Americans TodayTowards the 21st century, the themes of alienation and displacement thrive in the Native American communities. They are always dealing with issues and struggling to keep up with the changes in the American society.Many Native American tribes seek to be recognized by the government. There are currently ‘561 Native American tribes recognized by the U.S. government. These tribes are designated to have their own form of government, to enact laws, to establish tribal memberships, to issue license and regulate activities† (The U.S. Relationship to American Indian and Alaska Native Tribes, 2005).Today, Native American Indians continue to be a part of the American landscape and in the U.S. economy. Native American tribes established their own governments that offer services in law enforcement and disaster management. Most of the Native American tribes have their own legal system to settle disputes (Bureau of Indian Affairs, 2006).Gambling has become a big industry for the Native Americans. Most casinos operated by the Native American governments are seen profitable and has encouraged business diversification (Columbia Law Review, 2006).Sadly, most people are unaware of the plight and struggle of the Native American communities. For many Native Americans they still believe that they are still outsiders in the country and many feel that they are mistreated by the general public.Simon Ortiz used his own personal experiences from to shape his story. He tried to reach his audience by exposing the issues that surrounds the Native American community and their continued plight. His works reveal that the Native Americans want to restore their sense of â€Å"self† in order for them to fight for their rights and preserve their way of life.ReferencesA Resolution By the Native American Caucus. (2006). http//:www.turtletrack.org 8 February  2006. Retrieved on 15 December 2007.Baym, Nina. (1997). Norton American Anthology of American Lite rature. (p.2778). London:Oxford University Press.Bureau of Indian Affairs. (2006). http//:www.doiu.nbc.gov/orientation. 8 February 2006.Retrieved on 15 December 2006.Encyclopedia of American Literature. (1998). (p.858). Connecticut: Greenwood Press.Kaplan, Karen. (2005). Ancestry In A Drop Of Blood. http//:www.racesci.org. 30 August2005. Retrieved on 15 December 2007.Mixing Bodies and Beliefs: The Predicament of Tribes. (2006).Columbia Law Review.http//:www.columbia.org. 8 February 2006. Retrieved on 15 December 2007.Rock, Roger O. (1985).Native American Literature. Connecticut: Greenwood Press.The Black Mesa Syndrome: Indian Lands, Black Gold. (2006).http//:www.shundahai.org.8 February 2006. Retrieved on 15 December 2007.The Mukeman Ohlone. (2007). http//:www.mukema.org. 22 June 2007. Retrieved on 15December 2007.The U.S. Relationship to American Indian and Alaska Native Tribe. (2006). http//:www.usinfo.state.gov.8 February 2006. Retrieved 15 December 2007.ReferencesWalking A Mile: A Qualitative Study Exploring How Indians and Non-Indians Think AboutEach Other. (2007). http//:www.publicagenda.org. 7 December 2007. Retrieved 15December 2007.Wiget, Andrew. (1994). Dictionary of Native American Literature. (pp.115-133). New York:Garland Press.

Arguments against CSR

Corporate Social Responsibility While there may be people who are for the idea of corporate social responsibility, there are also others who oppose to it. One of whom, as we all know, is Milton Friedman. He believes that only individuals can have social responsibilities and that the purpose of a corporation Is to provide the highest possible returns to shareholders while obeying all the laws and regulations. There are 5 mall arguments against CARS.First of all, it lowers economic efficiency and profits. CARS also imposes unequal costs among competitors and imposes hidden costs which are passed on to stakeholders. Also, more often than not, carrying out these social responsibilities require skills which businesses may lack. Lastly, it places responsibility on business rather than individuals. A business may have to allocate a certain amount of resources Just to meet the needs of the people and environment.Suppose the firm currently has an unproductive operation in a certain country an d it would definitely be better for the company if it closes this operation down but this will also mean that al the employees will lose their Jobs and Income. This will affect their livelihood and probably their families as well. For the firm to have corporate social responsibility, this will mean that the firm will have to keep It going so as to ensure their well-being Is taken care of.However, this results In costs that are higher than necessary which ultimately leads to lower profits. Stockholders get a smaller return on their investments, making it more difficult for the firm to acquire more capital to sustain the company in the long run. Another example will be when a firm invests more in a reticular technology so as to ensure that environmental concerns are met but this may backfire especially if there is only a handful of consumers who actually care about these environmentally-friendly products.They may not be willing to pay a slightly higher price for such products. This ag ain reduces profits and lower economic efficiency. Money used in attaining greener technology can otherwise be invested elsewhere to yield higher returns that will be more beneficial to the company. Even though corporate social responsibility Is well-intended, such social costless lower businesses efficiency, thereby depriving society of higher levels of economic productivity needed to maintain everyone's standard of living.Moving on, the reason why it imposes unequal costs among competitors is because the more responsible companies would have incurred higher costs, putting them at a competitive disadvantage compared to other companies in the same industry. In a highly competitive market, the more responsible companies are even at risk of being out of business since their less responsible opponents will attempt to capture a larger market share.

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