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

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