Recent Posts
DNA Nanovases
Nanotechnologists from Arizona State University, USA have made "bowls", "flasks" and "vases" of nano-dimensions with nothing but DNA. This they have achieved using DNA Origami, a self-assembly technique where strands of DNA are folded and "stapled" together to make intricate structures just as paper is used in the conventional origami.
Who says we are happy?
A recent study by Professors from University of Vermont has suggested that our happiness has increased by 4% in the last few years. The internet based study collected data from blogs and analyzed the mood of its authors. A Science NOW article reports the results that is to be published in the Journal of Happiness Studies.
Is this really a good news? I do not think so...
Its hard to understand the rationale behind this 'investigation'. This study seems to assume that majority of people in the world have access to internet and that the most favorite activity of people around the globe is blogging and writing songs and making it available to strangers on the internet.
It is probably right to say that blogs reflect the mood of an individual. However, it is grossly inaccurate to believe that blogs reflect just that. There are blogs about virtually everything including fictitious accounts of one's life. Using selected words to assess the emotion of the blogger at the time of writing can lead to false picture of his/her state of mind. This is highly error-prone when the group under study comprises of young people who find it fashionable and trendy to use words that hold "dark" emotional values.
Have the scientists tried to analyze content from other languages? English is certainly not the only language people use. Neither is it the language used by majority of people in the world. This study is very clearly US-centric. It says, "The happiest day since 2005 was 4 November 2008, the U.S. presidential election, with a score of 6.3." While the population of United States hardly constitutes a major chunk of the world population, the number of people who find this news sensible is likely to be far too less and its incorrect to say that this study reflects the 'mood' of the world. I believe this is true even if one considers only those who use internet regularly.
The views of the professors are equally 'regional' in its implications and can never be extrapolated to the real world out there!
Bringing Back the Light
Glaucoma is a condition where the fluid present in the eyeball exerts too much of pressure onto the cells of retina causing the retinal ganglion cells to die. If left undetected/untreated, it causes blindness.
It is the second cause of blindness in the world. In addition to this, there are 2 reasons why one has to take this with utmost seriousness:
- It is known as 'sneak thief of sight' because people lose sight slowly and almost unknowingly. Often, it becomes recognizable only at the advanced stages.
- The damages to the optic nerve fibres are irreversibile.
This was the case until now...
If what a group of researchers from University of Rome are claiming is right, it will be possible to help revive the damaged retinal cells of the patients suffering from this painful disease. That too without having to undergo more painful therapeutic procedures or surgery but with just a few drops of an NGF - Nerve Growth Factor.
They have discovered that administration of NGF in the form of drops directly in the eye produces a considerable reduction in the damage caused to the retinal ganglion cells by increased intr ocular pressure. After success with rats, the same experiment was tried with humans. Amidst concerns about the soundness of the experiment and its interpretations, the neuroscientists have claimed that this works with humans as well.
While scientists debate on the authenticity of the results and the need to indulge in verifying the claims, one can only hope that this simple solution to this dangerous disease guides research leading to achieving the ultimate reversibility - bringing back light into the life of many of its victims!
Do They Taste Light?
Posted by Mad G
on
Tuesday
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Caenorhabtitis elegans
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My previous post was about the fact that C.elegans were sensitive to UV light. What made this more interesting was the protein that was discovered as responsible for this special character.
Conventional studies in these nematodes by Stacey L. Edwards, Kenneth G. Miller, and colleagues allowed them to identify a protein as being behind this interesting property. They called it, lite-1. Curiously, this protein was very similar to those that were known to be involved in tasting. Further investigations established that lite-1 did act as receptor for UV light.
This protein may soon find its way to the tool box of the modern molecular biologists. Perhaps, this protein also shows that there may be other proteins in higher organisms that are waiting to reveal their secrets!
Things are not what they seem to be... especially in the world of biology!
Seeing Light Without Eyes
Many of the ground breaking discoveries in molecular developmental biology were made with the help of simple organisms that can be grown in laboratories with ease. Caenorhabditis elegans is one among them. Measuring about a millimeter in length, these organisms had been a good friend for molecular biologists and neuroscientists for decades. One reason why a common man may find this kind of round worm interesting is that they managed to survive the historic Columbia space Shuttle disaster. (Find more information here.)
These survivors are continuing to surprise their masters and challenging the claim that their physiology is well-studied. Not many would have expected these underground creatures to show any interest in light. Shawn Xu, a neurobiologist from University of Michigan proved just that. Upon observing that these creatures shy away from bright light while he viewed them under the microscope, he set out to explain how these eye-less worms see light.
Further investigations by Xu and his team revealed that four pairs of sensory neurons of C.elegans were responsible for its sensitivity to light. And, these neurons made them reverse their course as soon as the light is switched on.
(Find a more detailed article in ScienceNOW)
(Find a more detailed article in ScienceNOW)
It was also found that these worms were more sensitive to the harmful UV-A radiations. This gives a clue to why evolution had gifted these simple organisms with this ability. Without these four neurons and hence the perception of light, the organisms may wander out into the light and get exposed to the harmful radiations. Such behavioral responses to light in such simpler organisms is more crucial to an evolutionary biologist, trying to understand the how higher vertebrates evolved sight.
DNA Crystallization in vivo
Bacteria are some of the marvelous creations of nature. They are known for their adaptability. The humble Escherichia coli that we find in almost all the microbiology and molecular biology labs continues to surprise us with its ingenius ways of handling problems.
Under extreme stress, bacterial cells are known to take many steps to protect themselves. Abraham Minsky of the Weizmann Institute of Science in Rehovot, Israel identified an interesting defense mechanism of E.coli thats slightly different. These unicellular organisms crystallize their own DNA.
This 'novel' defence strategy was found to be the responsibility of a protein called Dps. It resembles ferritin, an iron-storage protein found in humans.
Dps is produced when the cell experiences nutritive or oxidative stress. It binds to DNA (apparently without any specificity) and promotes its crystallisation. Earlier investigations revealed another important function of the Dps protein. It sequesters iron and other metal ions that may help in the generation of free-radicals.
Minsky and his collegues genetically engineered a few bacterial cells to over-produce this protein. These cells formed DNA crystals more easily and starvation was sufficient to cause crystallization of DNA. This process was also found to be reversible. "Once nutrients are supplied, [the crystals] disappear within a very short timescale, and the bacteria are viable and growing," says Minsky.
Whats remains to be explained is, how the bacterial DNA integrates itself into a crystal!
Stretching DNA on a chip
Posted by Mad G
on
Friday
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DNA carries all information a living organism requires for survival. Reading this information can be made much easier if you can get these 2nm wide polymer strand stretched and untangled. Researchers at Purdue University have done just that.
They have precisely placed strands of DNA on a silicon chip and then stretched out the strands so that their encoded information might be read more clearly. This may prove extremely critical in future electronic devices and computers.
Find more information here.
What made HIV infect Man?
Posted by Mad G
on
Wednesday
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About 4 million years ago, humans had split from apes. At this time, Chimpanzees had to go through some tough times. They were infected with a virus. Scientists discovered this when they found traces of this virus in the DNA of Chimps. This meant that this virus, called PtERV1, infected the Chimp population. Interestingly, the traces of the virus were not found in human genome.
Emerman and his team had an explanation. The humans immune to PtERV1 while Chimps had tough time fighting it. The team of researchers identified TRIM5 as the factor that helped humans protect us from the virus. Removing this protein from the cells made them vulnerable to PtVER1, which were reconstructed from Chimpanzees DNA.
Curiously, these cells were found to be less susceptible to HIV. It seems that in the process of developing resistance to one virus, the immune system of our ancestors had us vulnerable to another deadly virus, the HIV.
