Sunday, June 18, 2017


Letters from the basement and the Interesting science this week series have a new home at my new Wordpress blog, information factory. All the previous blogposts on Letters from the basement will still be here. 

The latest post in the interesting science this week series is up and you can find it here.

Thank you for your support and patience with my erratic posting schedule.

I hope information factory will have your support the way Letters from the basement had and I promise to make it worth your time. 

Friday, January 06, 2017

Interesting Science This Week. Week 7

In our modern liberal society, a great deal of effort has gone into eliminating the differences in how women are treated from men. In nature, however, male and female sexes have well defined roles in ensuring that perpetuation and evolution of life is not interrupted. Recently published research has indicated that the distinct biological roles of the two sexes also contributes to determining the lethality of infections by bacteria and viruses. It was well known that many bacterial and viral infections tend to be deadlier in men than in women. Men who are infected by TB causing bacteria, for example, are 1.5 times more likely to die due to infection than women. Similarly, many cancers are more likely to lead to death in men than in women. This difference in susceptibility to pathogenic infections among men and women was hypothesized to be due to the different sex hormones. However, in a recent paper published in the journal Nature Communications, researchers from Royal Holloway University of London have reported the results of their work that shows that the observed difference in lethality of bacterial or viral infections could be because it might be evolutionarily advantageous for the pathogen to keep the infected women alive. This, the researchers argue, is because women can transmit the pathogen to a wider population of hosts through pregnancy and nursing. To support their hypothesis, the scientists have examined the case of Human T-cell Lymphotorpic Virus Type-1 (HTLV-1) that causes Adult T-cell Leukemia (ATL), a type of blood cancer and is highly prevalent among Japanese and Caribbean populations. While the infection by HTLV-1 virus is equally lethal in both men and women in the Caribbean population, it is more lethal among Japanese men than women. The scientists have explained that this difference is because the Japanese women breastfeed for longer duration than Caribbean women. This incentivizes the virus to evolve such that they are less virulent in the body of Japanese women since that will help them survive longer. How the pathogen identifies the sex of its host is an interesting puzzle that needs to be unravelled through further research.   


Bats are probably one of the most vilified animals in our popular culture, along with Owls. Every horror or thriller movie has atleast one scene starring these flying mammals. Usually these scenes feature a large number of bats rushing out of a cave or some such desolate space accompanied by a lot of noise just as one of the characters is trying to enter. A group of researchers from Israel have now come out with a study where they have tried to understand if there is any meaning and purpose to these sounds that the bats make.  The results of this study have recently been published in the journal Scientific reports. To conduct this study, the scientists collected a group of Egyptian fruit bats in a room and continuously recorded their sounds and actions for 75 days. They then used a computer program to analyze thousands of sounds and correlated them to actions from the video recordings. From these analyses, the researchers identified that most of the sounds that the bats made were not random but had a specific context in the everyday life of the animals. Not only did these sounds have a purpose, they were also directed at a specific member of the group. The bat sounds also had different intonations depending on the sex of the recipient of the sound. Most interestingly, the scientists discovered that more than 70% of the sounds that they analyzed could be attributed to just 4 different behavioural contexts - quarelling over food, bickering about the sleeping spot, raising alarm when another member of the group came too close to a bat  and a female protesting against the attempts of a male bat to have sex. Apart from contributing to the understanding of the social behaviour of the bats, this work has the potential of forming the foundation to explore the vocal communication among other animals. 


Do take a minute to leave your feedback in the comments; it helps me stay engaged 

And do remember to check back in next weekend; there will be more interesting science in this corner of the internet. 

Saturday, July 30, 2016

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.      

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.

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. 

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.

Thanks for reading. Do take a minute to leave your feedback in the comments.

Saturday, July 23, 2016

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.

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.   

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.

Sunday, July 03, 2016

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. 

Please do take a minute to leave your feedback in the comments.

Friday, June 24, 2016

Interesting Science This Week. Week-3

Every time one ventures to watch a movie in India now a days, you are subjected to the gory images of cancerous tissues, patients etc and are warned about the relation between use of tobacco and incidence of cancer. You are probably aware that cancer happens because of changes to the DNA in a cell which then goes berserk, looses all regulation and starts diving abnormally. The cancerous cells in a tissue eventually move out in a process called metastasis and spread to other parts of the body damaging the tissue there. This sequence of events is now pretty common knowledge. But have you heard of super-metastasis where the cancerous cells move out of one body and infect another? This is a rare process that has till now been discovered only in two animals where the cancerous cells are transmitted by bodily contact, either through bite (Tasmanian devil) or through sexual mating (dogs). But in a recently published report in the journal Nature, scientists have shown that the transmission of cancerous cells can happen even through water. This phenomenon was observed in a class of molluscs called Bivalves including mussels, cockles and golden carpet shell clams.
  • Metzger et al., Nature, 2016. DOI: 10.1038/nature18599  
It's monsoon time in India and the puddles of water seen everywhere offer abundant breeding grounds for nature's master disease carriers, the mosquitoes. But what makes mosquitoes so efficient in being able to spread pathogens? The answer is, according to recent research findings, our own immune system. The most common reminder of having spent a good night futilely trying to fend off the mosquitoes are the red welts seen on the body next morning. The research suggests it is the inflammatory reaction resulting in these welts that aids the efficient spread of pathogens injected by the mosquito bite. The inflammatory response is due to a local reaction that serves to warn the body that skin, which is the first defensive barrier against infections, has been breached. This activates the body's immune response and leukocytes (also called white blood cells) are mobilized to the site of inflammation in order to contain the infection. Researchers have found that, the immune cells that reach the spot of mosquito bite themselves get inadvertently infected and contribute to rapid spread of infection to rest of the body. This hijacking of the immune cells by pathogens might be due to help from certain molecules present in the saliva of mosquitoes that get injected at the point of bite. This conclusion is based on the observation that injection of the same pathogen into the body with a needle did not produce an infection of comparable intensity as when injected by a mosquito bite. Researchers also suggest that the ability of mosquito bites to promote infections can be ameliorated by suppressing the initial inflammatory reaction. 
  • Pingen et al., Immunity, 2016. DOI: 10.1016/j.immuni.2016.06.002 
 There is a nice write-up published in Quanta Magazine detailing the research about a class of micro organisms called the Lithoautotrophs, or the rock-eaters, that survive by consuming only electrons as their source of energy. As such, these microbes can be described as "electricity-eaters".

Friday, June 17, 2016

Interesting Science This Week. Week-2.

As kids we heard the story of a crow that strategizes by using pebbles to bring the level of water in a pot to the brim so it can drink. We have also heard parrots that were trained to speak like humans. For a very long time in human history, messenger pigeons served as the only reliable means of long distance communication. More recently, pigeons were shown to be almost as good as trained doctors in detecting cancer and scientists have made visual recording of the ability of crows to make hooked tools. Have you ever wondered how birds, with such small heads, can manage such feats that animals with much larger brains cannot accomplish? A group of scientists have now found the answer. In their recently publish work based on studying the brains of 28 species of birds, Seweryn OlKowicz and colleagues have found that the bird brains contain at least twice as many nerve cells (neurons) as a similarly sized mammalian brain and the nerve cells are packed at a much higher density. They also discovered that most of the extra neurons in birds are found in the forebrain responsible for learning, planning, etc. So much so that the number of neurons found in the forebrains of some of these birds was more than or comparable to those found in monkeys with much larger sized brains. 

  • Olkowicz et al., PNAS, 2016, DOI:10.1073/pnas.1517131113
  • Levenson et al., PLOS, 2015, DOI:10.1371/journal.pone.0141357
  • Troscianko and Rutz, Biology Letters, 2015, DOI:10.1098/rsbl.2015.0777 

The red color of our blood is due to a complex protein called Hemoglobin that transports oxygen and carbondioxide between lungs and various tissues of the body. Hemoglobin is made up of 4 subunits each of which transports a oxygen molecule. Each Hemoglobin subunit in turn is made up of a protein chain that surrounds a non-proteinaceous part called Heme. Each Heme moiety consists of an iron ion (which is the part that actually binds oxygen) within an organic ring called Porphyrin. Heme is synthesized in the red blood cells in a multi-step process involving about 8 different enzymes. In people suffering from a group of rare genetic diseases called Porphyrias, there is an accumulation of porphyrin in the cells due to a defect at one or more steps in the Heme bio-synthetic pathway. People suffering from porphyria often develop irritation, burns or blisters in the skin upon even medium duration exposure to sunlight. In severe cases, porphyria can lead to even neurological disorders. Yet, there is currently no real cure for this condition. In a recent work published in the journal eLife, a group of scientists from United States and Canada have reported the discovery of a type of flatworm (Schmidtea mediterranea) that naturally accumulates porphyrin in its skin cells. These worms, which are naturally brown colored, lose their color and turn white when exposed to sunlight for a prolonged period of time due to cell death induced by accumulated porphyrin. It is also reported that the natural color of the worms is restored after returning to dark. Scientists expect that these worms could be used as model organisms to study the biological processes leading to the development of porphyria in humans as well as to analyze the efficacy of potential drugs that could be used in treatment of porphyrias. 
  • Stubenhaus et al., eLife, 2016, DOI: 10.7554/eLife.14175 
'Frogman of India' S.D.Biju is back in news. In a recent report published in the journal PeerJ, Dr. Biju and colleagues report the discovery of a new mating position in the frogs. They have made this report based on their work on Bombay Night Frogs (Nyctibatrachus humayuni), a type of frog that is endemic to the Western Ghats of south India. There were 6 different types of amplexus (mating positions) that were previously known among the amphibians; with the discovery of this position, called the Dorsal Straddle, the number increases to 7. The researchers also report the discovery of female mating calls in this species of frogs that is rare occurrence among the amphibians. 
  • Willaert et al., PeerJ, 2016, DOI: 10.7717/peerj.2117 
Earlier this year we heard the first ever recording of the 'sound of the Universe' when the LIGO scientific collaboration unveiled the discovery of Gravitational Waves. Now the team has reported the discovery of second such event in an article published in Physics Review Letters. The signal was identified on 26th December 2015 and involved the collapse of two stars that are much smaller than the two involved in the first discovered event. While the two stars that collapsed to produce the gravitational waves during the event detected in September of last year were 36 and 29 times more massive than our own Sun, the two stars involved in this event were only 14 and 7.5 times more massive. 

  • Abbott et al., PRL, 2016, DOI: 10.1103/PhysRevLett.116.241103