Interesting Science This Week. Week 5

Originally posted on July 23, 2016 at my blogger site.

Bacteria in your stomach is making you fat. That is the conclusion from a recent study published in the journal Nature. It is reported that the gut microbiome, a collective term for bacteria and other microbes that reside in the stomach of humans and other animals, could be responsible for the development of obesity in those constantly exposed to high fat diet. The researchers found that mice regularly fed on high fat diet showed an increase in the concentration of acetate in plasma, feces and brain. Acetate is a short-chain fatty acid produced as a result of digestion of fats. When the mice were either treated with antibiotics or were maintained in a sterile environment, they failed to produce increased acetate even with high fat diet which led the researchers to conclude that the acetate was produced by the action of gut bacteria. The acetate so produced by bacteria reaches the brain, possibly through blood, and induces the brain to send a signal to pancreas to increase the production insulin which in turn leads to fat accumulation and consequently to obesity. Acetate was also found to cause an increase in hunger hormone, ghrelin, which causes the animals to consume even more food, further exacerbating the obesity. It remains to be seen if these observations on the link between gut microbiota and obesity can be extrapolated to humans. But if these observations hold true in humans, it could pave way for further more drug-targets to fight obesity.

There is some good news for those of us tortured by mosquito bites. Research has found a very effective method to keep those malaria carriers away; take a chicken along when going to bed. According to a recently published report, when scientists took a host census of malaria carrying mosquito Anopheles arabiensis, it was found that the insects fed on humans indoors and on cattle, goats, sheep etc. outdoors. But the mosquito totally avoided going anywhere near chickens. The researchers have identified 11 compounds from chicken feathers which when spread near a sleeping human were effective in keeping the mosquito away. Since it is going to take some time before the actual chicken mosquito-repellent is purified and marketed to general public, having some chicken companions in bedroom could, in the meanwhile, help you get a good night’s sleep.

It was traditionally thought that brain was separated from immune system but recent studies have shown that immune system defects can effect learning and memory. In a recently published study the same research group has now shown that immune system could also have an effect on the social behavior of the animal. It was found that a molecule called interferon-gamma, which is normally produced as an immune response to infection by bacteria, virus and other pathogens, is crucial for social behavior. Blocking the production of this molecule in mice resulted in them becoming less social. The researchers also found that this molecule was produced by various organisms including flies, zebrafish, mice, rats etc. when they were social.

In laboratory setting, a technique called electroporation is widely used to introduce DNA and other molecules into cells. In this technique, the cells are subjected to short electric pulses which causes formation of temporary perforations in the membrane surrounding the cell (called Plasma Membrane) through which DNA can enter the cell. The plasma membrane is eventually repaired and the perforations are sealed returning the cell to its normal health. The electroporation is also used in cancer therapy in conjunction with chemo-therapeutic drugs. It is observed that electroporation is more effective by being more damaging to malignant cells than normal cells. But the reason behind the efficacy of treatment strategies that include electroporation in specifically targeting malignant cells is not known. In a paper published in the Journal of Membrane Biology, data is presented that shows that the plasma membrane of cancer cells is resealed more slowly than normal cells following electroporation. This slow repair of plasma membrane ensures that drugs or DNA have more time in which to enter the cancerous cells than normal cells, increasing the efficacy of treatment.

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