Paper on Arabidopsis cold responses Essay Example | Topics and Well Written Essays - 1000 words

Paper on Arabidopsis cold responses - Essay Example It is widely speculated that the products of these genes have roles in freezing tolerance. The aim of this experiment was to provide direct evidence that supports this hypothesis. It shows that expression of COR15a, which is a cold-regulated gene of Arabidopsis thaliana that encodes a chloroplast-targeted polypeptide, enhances the freezing tolerance of chloroplasts in nonacclimated plants. The Effects of Cold Stress on the Cor15a Promoter of Arabidopsis thaliana In 1985, Guy et al. established that transformations in gene expression occurred in plants during cold acclimation, which is a developmental mechanism that leads to increase in freezing tolerance. Since then, it has continuously been speculated that some COR (cold-regulated) genes might play roles in freezing tolerance. To investigate this notion, scientists have isolated and characterized genes expressed as a response to low temperature. This has led to the identification of a number of genes such as the cor15a, KIN1, and LT I78 genes of Arabidopsis thaliana; and the pt59 and pao86 genes of barley (â€Å"Genome research†, 1995). Arabidopsis thaliana is widely used in botany as the model organism for studying plant genetics and growth responses. This plant is a member of the mustard (Brassicaceae) family, which includes cultivated species such as cabbage and radish. Although Arabidopsis thaliana does not have any major agronomic importance, it has advantages that make it ideal for use in research in the fields of genetics and molecular biology. The first advantage of Arabidopsis thaliana that make it favorable for research  is its small physical size, its fast growth rate, its capability in seed production, its genetic amenability to mutagenesis and transgenic approaches, and the widely available information on its genome. Secondly, Arabidopsis thaliana is well-suited for analysis with light microscopy. Its seedlings and their roots are translucent and smaller, thus they facilitate live cell ima ging with fluorescence and confocal laser scanning microscopy. Lastly, Arabidopsis thaliana is the first plant genome to ever be sequenced. This was completed in 2000 by the Arabidopsis Genome Initiative (Stewart, 2008). Most plants react to low temperatures by altering their intracellular concentrations of free amino acids and carbohydrates, isozyme patterns, and the composition of their membranes. Moreover, in response to low temperatures, there is an alteration in the activity of many genes. Dr. Michael Thomashow of Michigan State University conducted studies on how plants respond to cold temperatures. He examined cold-induced genes in the plant Arabidopsis and cloned cor (cold related) genes. One of these genes, cor15a, is induced by cold temperatures, drought, and the hormone abscisic acid. Cor15a is a nuclear gene that encodes a 15 kDa protein. The function of this protein is unknown. This 15 kDa protein is translated to chloroplasts and it may have a function in plant protect ion from cold. (Baker et al., 1994) isolated a DNA fragment that contained a promoter region and a few amino acids from the cor15a gene. They then joined it to the gusA gene, thereby producing a cor15a-gusAtranslational fusion which was introduced into Arabidopsis thaliana using Agrobacterium. This reporter gene is used in monitoring the response of the cor15agene in varied plant tissues. In this laboratory investigation, transgenic

Rabelais and Montaigne Essay Example | Topics and Well Written Essays - 1250 words

Rabelais and Montaigne - Essay Example This is especially so as they give credence to art in its natural state where a lot of description and opinion, but which seek to indulge into inquiry. Even so, to argue that renaissance writers were only interested in theory may be a misconception. This paper shall assess the above claims under the thesis statement: early renaissance writers and characters appreciated theoretical generalizations and pragmatic action in equal measure. To do so, this paper shall focus on selected readings of the above scholars in an attempt to prove this position. The paper will also offer a counter argument through the lens of an alternative interpretation especially where ambiguity leaves room for multiple understandings of the texts. An Analysis of Depictions of Pragmatic Action versus Theoretical Generalizations To begin with, Book 1, the introduction offers a bit of the author’s background. One may notice that the fact that he threw himself at the movement of the Renaissance (Rabelais and Raffel 5). He is depicted as having acquired both the Latin antiquity knowledge as well as the Greek forms of knowledge. Raffel writes, â€Å"Almost all the elements which are united in Rabelais’ style are known from the later Middle Ages (Preface page X). It is observable that since the author lived at the intersection of two historical periods, it was inevitable that he was affected by the mannerisms and beliefs of those times. It is also observable that Rabelais did not always write in the same fashion (Rabelais and Raffel 12). Analyses of chapters 52-58 reveal some perceptions of the renaissance writers and characters about religion and logic. There was a lot of attention given to theory. For example, Rabelais says, â€Å"If one of the gallants of ladies should say, let us drink, they would all drink.† This depicts a situation in which the society did not assess keenly how practically their actions could affect other things around them. For instance, Rabelais†™s work reveals in this chapter that the society perceived women as incapable of religious service. When the monk asks Gargantua what a good â€Å"a woman that is neither fair not good† serves, Gargantua replies that she should make a nun (Rabelais and Raffel 127). The monk agrees to this. One may observe that these renaissance characters depict religious principles were still important to the society. These show to theoretical approach to life. Besides, there is a lot of description of the abbey of the Thelemites, particularly in regard to how it was built. The author takes his time to describe the abbey, as was the common practice in romanticism. Rabelais’s says this of the abbey in chapter 52, â€Å"In the midst there was a wonderful scalier or winding stair, the entry whereof was without a house, in a vault or arch six fathom abroad.† He also engages in detailed description, a characteristic of theoretical life. he says in chapter 54, â€Å"Stay here, you lively, jovial, handsome, brisk, gay, witty, frolic, cheerful, merry, frisk, spruce, jocund, courteous, furtherer of trades, and in a word, all worthy gentle blades. This approach to life combines what one would call emerging pragmatism against a fading romanticism. Rabelais observes in what he termed a prophetical riddle, that â€Å"they will say that everyman should have his turn† (Rabelais and Raffel 137) to imply the births of human rights in the post renaissance period. He also continues with theoretical appro