Hi there! It is halfway through the semester, how is everyone? I have been busy applying for a PhD and writing assignments recently. The format of the assignments this semester is slightly different from my first and second year. Even though the workload is heavy, I found the assignments very interesting. This may be because of the format of the assignments, which is slightly different from my first and second year, which is always essays and lab reports.
Today, I would like to share two of my assignments with you and tell you why I enjoy doing them. The first assignment is a problem based learning (PBL) assignment of the module, Advanced technologies in gene expression. We (a group of five) are given a task to resolve a recombinant protein expression problem. For example, we are given a situation like this: ‘We are team members of a molecular biology team at a large pharmaceutical company that has decided to manufacture recombinant human serum albumin to replace product purified from human plasma. The market for serum albumin is estimated to be 500 tons per year worldwide. It is used in a variety of clinical indications. The director of research has tasked you with developing an expression strategy report for the production of recombinant serum albumin.’ We have to discuss among our group and figure out an expression strategy to produce the recombinant protein of human serum albumin for clinical use, and submit a professional report.
This kind of assignment is pretty interesting. It allows us to think about the practical issues of protein expression, and helps path our way/ prepare us for the potential problem we might come across when we work in the industry after graduation. To work out the strategy, we have to consider the size, structure, function and properties of the protein. Then, we need to identify the requirement of the PBL case. For example, since our target protein is for pharmaceutical use (500 tons in the market), it’s not recommended to go for mammalian cells for protein expression, as the cost would be incredibly high (for your info, the liquid broth for cell culture cost £150/L, and we might need at least thousands to ten thousand litres just for the broth).
Sometimes, when we start doing research, we will realise some practical challenges that we haven’t come across in textbooks/everyday lectures. For example, to maximise the yield of protein expressed, we need a yeast strain that is protease deficient (to avoid the protein of interest being digested), and with similar machinery of protein translation and post-translational modification. The strain also has to allow methanol independent induction of protein expression (because a large amount of methanol is toxic to cells, and we don’t want to add a large amount of the flammable liquid into our bioreactors). However, in practice, it is impossible to acquire such a perfect yeast strain that can do everything. We can only select the strain with the most needed property, and try to obtain the other properties by using suboptimal approaches. We also have to consider the cost and scale of protein expression at the same time. I should say that the report is actually difficult because we haven’t got any real experience in expressing the recombinant protein. However, I enjoyed it very much as it involves problem-solving thinking processes, and structure organisation skills too.
Another assignment is the group presentation. In the module called clinical immunology and immunohematology, we formed a group of six to present a real clinical case. We need to make a diagnosis based on patient history, symptoms and test results. Also, we need to explain the immunopathological mechanisms that could lead to the symptoms reported, then suggest further tests to rule out other diagnoses. Finally, we have to provide a likely prognosis and recommend further treatment. I feel like there is more critical thinking involved in this assignment. In the real clinical world, we couldn’t 100% confirm a diagnosis of a patient, as there are so many impact factors to take into account of. For example, let say we think that the patient has Systemic Lupus Erythematosus (SLE), the patient won’t necessarily manifest most of the symptoms of the disease. Alternatively, a patient may manifest some symptoms of SLE patient, but the test results (eg. blood test, antibody test) did not show abnormality. Hence, we need to look at other parameters to further confirm the possibility of whether the patient gets SLE. It is rather difficult to get a clear-cut diagnosis.
Overall, I feel like the modules in my final year are more practical and clinical based, which really equip us with solid fundamental clinical/ industrial skills, as well as strengthen our knowledge of basic science. This would definitely prepare us for our future careers, both in academia, industry and clinical environment.