Thursday, February 27, 2020

Antibodies Essay Example | Topics and Well Written Essays - 1500 words

Antibodies - Essay Example It is used in the manufacture of unsaturated polyester resins and is used as solvent for surfactants, paints and cleaning agents1. It is also used as antifreeze for de-icing aircrafts at airports as it lowers the freezing point of water. Recent applications include use as a humectant and a preservative. It is used in cosmetics, pharmaceutical preparations and also in electronic cigars2. The structure of 1,2-Propanediol comprises of three carbons with a stereogenic center at the central carbon3. It exists in two racemic forms: S and R as shown in figure 1 below. Figure 1: Chemical structure (S and R form) of 1,2-propanediol 3 1,2-Propanediol as well as 1,3-Propanediol can be manufactured though bioengineered microorganisms. By turning on and off some genes, it is possible to make the microorganism overproduce a specific metabolic product. As shown in figure 2, the intermediate metabolism of Escherichia coli can be shifted to produce 1,2 and 1,3-propanediol using enzymes such as aldose reductase from rat lens, E. coli glycerol dehydrogenase and Klebsiella pneumoniae glycerol dehydrogenase and 1,3-propanedioloxidoreductase4. There are various biochemical pathways through which 1,2-propanediol can be produced. Figure 2: Metabolic pathway engineering of E. ... It was shown that E. coli can grow on the L-fucose and L-rhamnose deoxy sugars as sole carbon and energy sources resulting in the production of propanediol. The first instance of metabolic engineering to produce 1,2-propanediol was when Altaras and Cameron metabolically bioengineered the 1,2-propanediol pathway in E. coli7. In 1999, they reported that E. coli that overexpressed methylglyoxal synthase gene produced 1,2-propanediol. Expression of methylglyoxal synthase or glycerol dehydrogenase led to anaerobic production of around 0.25 g of 1,2-propanediol per liter. The yield was found to be higher both the enzymes were coexpressed7. The development After their first report of the production of 1,2-propanediol from metabolically engineering E. coli, Altaras and Cameron again in 2000 published another report. This time they reported enhanced production of 1,2-propanediol8. They investigated three methods. First method involved the elimination of lactate byproduct. The second method in volved the construction of a complete pathway from dihydroxyacetone phosphate – an intermediate of the glycolytic cycle. The third method involved bioprocessing improvements through fed-batch fermentation using the best bioengineered strains. They were able to successfully produced a final yield of 0.19 g of 1,2-propanediol per gram of consumed glucose. Many later studies have investigated the production of 1,2-propanediol by metabolically engineered bacteria. Berrios-Rivera, San and Bennett studied the effects of various cofactor manipulations on the production of 1,2-propanediol9. They used sugars that were similar to glucose and that can be fed into glycolysis for pyruvate production. The sugars used had different oxidation

Tuesday, February 11, 2020

Sigmund freud Essay Example | Topics and Well Written Essays - 1000 words

Sigmund freud - Essay Example The theory carries with it some weighty assumptions. One is that, we as individuals, know components of psyche, we know about the brain and also the nervous system. The second assumption is that we know how we act unconsciously. Hence psychoanalysis studies the suppression of some of the basic instincts (Freud 1937). According to Freud this suppression is constant and ongoing. Psychoanalysis may speed up the rates at which clients get better. It is also vital to note that, the nature of psychoanalysis creates a power imbalance, between the physician and the client. The id can be termed to be the most valuable part of the psyche. It usually contains urges that are extremely primitive. It is comprised of all the basic biological urges. A good example of some of this urges are hunger, thirst and sex. This part of psyche usually seeks pressure blindly. It does not care about the consequences; its aim is to seek instant gratification. Ego is developed from the id. It seeks to satisfy the id; it does so in a precise practical manner. It decides whether or not satisfaction is appropriate, and if favourable with the outside world. Commonly the ego is called self since it has the capability to look after itself. The superego is the third portion of the psyche; it develops with maturity. It has the sole responsibility of deeming the person’s actions good or bad. For Freud, there is a constant conflict between demands of the instincts and the demands of the society (Freud 1937). This can be caused by some of the impulses that may be hidden or even denied for lengths of time. However, this demands, in one way or another, reasserts themselves. The inner conflict is usually unknown and hence, it appears in thoughts and deeds that appear to be irrational. Psychologists that use psychoanalysis often see their patient’s problems as rooted in the unconscious part of