Question

 

A BUG AGAINST OBESITY. The fastest spreading illness in the developed world is obesity. While willpower and nutrition choices are certainly important for controlling obesity, increasing evidence supports the hypothesis that elements of the microbiome are also important. Using synthetic biology approaches, develop a "probiotic" bacterium that can safeguard against obesity. You may use one of two approaches. First, you can design an organism that will consume excess calories, leaving only the appropriate amount for the host. In this case, make sure to take into consideration the fact that the host also needs a number of other nutritional factors -- N, P, Fe, vitamins -- and the bacterium must make sure to leave these behind as it consumes "calories". The second approach is to design a bacterium that will target and kill specific strains of bacteria known to enhance obesity -- mostly enteric Firmicutes (e.g. "Gram-positive" bacteria). These bacteria must be able to both FIND (by swimming towards them) and KILL these bacteria with specificity -- i.e., they leave all the other "normal flora" intact.

****Instructions:

1. Don’t say anything factually wrong. Speculation is okay, but point out when you’re speculating and justify your speculation with facts.
2. Don’t say anything irrelevant. (i.e., don't throw up everything you can think of hoping some of it will stick)
3. Provide justifications for every non-obvious point. Citations are helpful – especially to things in your textbook that I can easily look up!
4. Make sure your answers proceed logically and that you have a clearly stated thesis or hypothesis that is supported by evidence that’s appropriate to the question.
5. Use "normal language" as much as possible -- avoid "big sciency words" especially if you think there's any chance I will question whether you know what they mean. In other words, don't vacuum up material from the internet and put it into your answer.
6. Don’t write more than 1500 words. If you’ve got more than that, consider using drawings and other types of figures to get rid of some words.

Answer 1

"A Bug against Obesity"

Eating too much and not doing excercise causes Obesity. When we consume more calories, in the form of sugars and fats, and not burn off these by doing excercise or physical activity, then this surplus energy will be stored as fat in our body. Obesity develops gradually overtime, the reason could be due to poor diet and lifestyle, lack of physical activity.

Role of Microbiome in Obesity:

Microbiome (probiotics) are important for health benefits and they have been used as therapeutic agent for metabolic disorders. Probiotics are a group of beneficial microbes that confers health benefits when consumed in an adequate amount. Genetic makeup in the host cell is also one of the factor of metabolic disorders and diseases. The composition of gut microbiota (GM) and its function can be altered by consumption of improper diet, which affects the health status of the host, resulting to obesity. Gut microbiota (GM) is required for energy balancing, intestinal integrity, and immunity against invading pathogens.So, GM can be positively altered by probiotic supplementation, thereby treating illness of diarrhea, allergy, gastrointestinal disorders etc. The gut microbiota makes an important contribution to human metabolism by contributing enzymes that are not encoded by the human genome, for example, the breakdown of polysaccharides, polyphenols and synthesis of vitamins. Intestinal bacteria can also synthesize biotin, Vitamin B12, folic acid, and thiamine. Iron supplementation is boosted by the bacterial siderophore, enterobactin, which associates with host mitochondria when bound to Fe3+ ions. They also leaves behind N, P, for the host.

Eg. Pediococcus pentosaceus and Saccharomyces boulardi.

The gut microbiota are the sum of all bacteria that are present in the gastrointestinal (GI) tract starting from the oral cavity and increasing in its density along the small and large intestine. The gut microbiome Firmicutes, have important protective, structural, and metabolic functions. It  protects the host by displacing harmful bacteria, competing with pathogens for nutrients, and producing anti-microbial factors. Moreover, they help the host with structural functions like developing the immune system, inducing immunoglobulin A (IgA), and reinforcing the mucosal barrier. The commensal bacteria provide metabolic functions to benefit the host by synthesizing vitamin K, folate, and biotin. Also it helps in the absorption of magnesium, calcium, and iron ions. . Degradation of dietary polysaccharides and fiber by Firmicutes produced SCFAs, eg.propionate, acetate, and butyrate. Acetate is used in peripheral tissues as a substrate for cholesterol  while butyrate is a rich energy source for the epithelial cells that line the colon. Firmicutes resulting in increased fermented end products, including SCFAs. Firmicutes which produced SCFAs from non-digested dietary compounds has been made as a marker for obesity. The most abundant Gram-positive commensal bacteria present in the gut, has been linked with obesity.