Interesting Science This Week. Week-6

The basic idea of of immunization is to inject inactivated pathogens or their parts which then activates and prepares the body's immune system to fight infection by live pathogen in future. Development of innate immunity in the body involves production of specific proteins called antibodies which will identify the pathogen during an infection. After antibody binding to the pathogen, a group of proteins called the Complement system assists in further processing and eventual clearance of the pathogen from the body. 

Malaria is one of the deadliest diseases in the world inflicting greatest damage in the developing and under-developed countries. As per WHO, there were 214 million cases of malaria in 2015 resulting in 438,000 deaths. In India itself there were more than 1 million malaria cases and 287 deaths, according to the data available with National Vector Borne Disease Control Programme. In keeping with the seriousness of this disease, efforts have been going on for several years now to develop a vaccine against malaria. The efforts till now have been without much success because prospective vaccines that worked in blocking the parasite in laboratory conditions were not effective when tested in humans. But in recently published research, scientists seem to have identified the reason behind the failure of these vaccines in animal trials. It appears that the malaria pathogen, Plasmodium falciparum, exploits the immune response generated in response to the vaccine to further its infection. The pathogen uses the components of the complement system to enhance its ability to enter the red blood cells (RBC) inside which it replicates. The presence of antibodies in the blood only further enhances the exploitation of complement system by P.falciparum. It was further shown that complement deficiency in mice resulted in decreased efficacy of infection by the pathogen. These results are a very important observation that could inform the future design of strategies towards a successful development of anti-malaria vaccine.      

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Most people know regular exercise is required for good physical health. What is less well known is that exercise also helps with mental health. Regular exercise helps keep the brain active, improve memory and learning and helps in dealing with conditions such as depression. One of the many factors which contributes to this effect of exercise on mental health is the increased production of a protein in brain called Brain Derived Neurotrophic Factor (BDNF) after exercise. BDNF is a growth factor required for growth, maturation and upkeep of nerve cells. This protein also actively participates in the formation and maintenance of connections between nerve cells (called Synapses) which are required for learning and long-term memory. How exercise contributes to increasing the synthesis of this protein was, however, not known. A group of American researchers have addressed this missing link between exercise and mental health in a recently published report. They found that in mice exercise resulted in increased production of beta-hydroxybutyrate, a metabolite produced in the liver when fatty acids are used as energy source instead of glucose. The beta-hydroxybutyrate that reaches brain through blood activates the DNA in brain cells that codes for BDNF to be translated into protein molecules which then help with improved brain function.

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The cells in our body can be divided into two types based on the number of sets of chromosomes they contain - diploid and haploid cells. Diploid cells contain two sets of chromosomes (each set contains 23 chromosomes) each derived from one of the parent. Most of the cells in our body are diploid. Only haploid cells in the body are the gametes (or the sex cells, sperm in males and egg or ova in females) that are involved in reproduction. These cells contain only one set of chromosomes. Scientists have been trying to grow these gametes in laboratories for a while now in order to better understand their biological development process. Sperms have already been cultured successfully in petridishes before. In a report published in the journal PNAS, scientists have now reported successfully growing a mature, functional ovum (egg) from mice in laboratory conditions. These lab cultured eggs, fertilized with sperm and implanted into surrogate mothers, lead to the birth of healthy mice. Apart from serving as a critical tool in studies to understand the development of ova, the technique reported in this publication can also be useful in future for treatment of female infertility. 

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There is a new map of brain. After more than 100 years since the publication of the first map in 1907 identifying different regions of brain to various functions, scientists have now published the new map where they have identified 97 new areas in addition to the 83 previously known using the data available from the Human Connectome Project. New York Times has published a report on this development (which you can find here). For the technically inclined, you can find the original paper published in the journal Nature here.

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Interesting Science This Week. Week-5

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.

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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.

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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. 

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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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Edit: Realized a little late. This is my 50th blogpost. Thank you all for the support. Keep reading. Do share your feedback in the comments.

Interesting Science This Week. Week-4

Have you ever been to a hospital for a health check-up and wondered, while the doctors and nurses were poking needles and probes all over your body, if there was an easy, less painful way to do things? Worry not, the science gods have answered your prayers. According to a recently published research report, the state of a person's health can be predicted from his/her facial features. For the study, a group of researchers from China looked at 3D scan images of the faces of more than 300 people (both male and female) in the 17 to 77 age range. For each age group and each gender, the scientists generated average 3D images of faces and from comparing their facial features such as eye slopes and nose width generated a map of changes in facial features with ageing. When the average 3D faces of a particular age group was compared to real faces, it was found that on average the chronological age of a person differed from their facial age by about 6 years. The most interesting finding in this study was that biological parameters such as the blood profile of a person coincided more with their facial age than the chronological age. What that means is that, you might be 50 years old but if the machinery inside your body resembles that of a 45 year old or of a 55 year old, it is going to show on your face. The face, it seems, is the mirror to not just the mind. 

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