. Monday, May 28, 2007

The active components of the cone snail venom are a group of neurotoxins called conotoxins. These are usually 12 to 30 aminoacid residues long. The peptides are highly constrained due to high density of disulphide bonds.

Although conserved structures are present in these peptides there are also subtle differences. These differences are responsible for the high toxicity and high specificity. These differences also ensure that each species has a unique subset of toxins. It has also been found that sometimes, the toxins differ even among individuals of the same species.

The conotoxins present in the fish eating cone snails are more effective against humans than those present in the mollusk eating snails.

The cone snail venom causes paralysis. The paralytic conotoxins belong to three main classes: alpha, mu and omega conotoxins. There are also others ... delta and kappa conotoxins.

You will find a list of conotoxins here.

More of Cone Snails...

. Sunday, May 27, 2007

These amazing creatures are not only found in the deepest parts of the oceans but also on the shores. While the shell of the snail lets it camouflage and wait for the prey, its siphon provided with numerous chemosensors detects the prey that happens to linger dangerously close. The proboscis containing what is probably the most efficient hypodermic needle of nature loaded with the most potent concoction of dangerous toxins is ready for the prey.

The lack of physical agility of these seemingly lazy predators is well compensated by their lethal venom. Within seconds of injection of the deadly cocktail of some 100 different conotoxins, the victim immobilizes. The snail engulfs its paralysed prey and swallows it whole.

Click here to view an amazing video depicting just this.

Cone Snails

. Saturday, May 26, 2007

Have you ever wondered how those lazy small snails catch their prey?
Well, here is how they do...

Cone snails are some of the most amazing creatures in the world of marine animals. Very little is known about them. They have a mind-blowing variety of toxins. These toxins are usually about 12 to 30 amino acid residues long with unusually large numbers of disulphide bridges. The toxins are so diverse that no two species of cone snails have same toxins. Even the composition of different toxins in their venom differs.

The pharmaceutical potential of some of these toxins have been identified and are in clinical and preclinical studies. These toxins can be used in the treatment of various diseases, from hypertension to depression.

Toxin - Nanoparticle Combine Defeats Cancer

. Thursday, May 24, 2007

Diptheria toxin is a protein secreted by Corynebacterium diphtheriae.

The protein has three domains - A, B and T. The B domain is believed to be responsible for recognizing the cell surface receptors. The toxin is found to show affinity for heparin binding epidermal like growth factor like precursors, which are found on the cell surface. T domain aids the protein to gain entry into the cell.

The A chain has the enzymatic activity. It catalyzes the ADP ribosylation of eukaryotic aminoacyl transferase II. This prevents protein biosynthesis in the cells leading to cell death.

The diphtheria toxin A (DT - A) chain's toxic properties can be exploited by properly guiding them to the cells that need to be killed.

This is exactly what the researchers have done using nanotechnology.

A nanoparticulate system made of Poly(beta amino ester) polymer and poly( butane diol diacrylate co amino pentanol) was used to deliver the diphtheria toxin A (DT - A) gene. This gene is linked to a regulatory sequence that gets activated only in prostate cancer cells. While the specificity is taken care of by the gene regulator, safe delivery of the toxin into these cells is the responsibility of the nanoparticulate system. Now, the diphtheria toxin does the rest.

Studies in the laboratory show promising results. Well, I guess we can expect efficient nano based injectable or ingestible drugs to treat cancer in the near future.

Now Polonium...... then Ricin!!!!

. Wednesday, May 23, 2007

Alexander Litvinenko was assasinated in london recently. He was poisoned by radioactive Polonium 210.

Alexander Litvinenko had earlier accused the Kremblin of involvement in the death of about 300 people in Russia in 1999.

This is not the first time Russia stands accused of silencing its critics abroad through assassination.

In 1978, Georgi Markov, a communist defector was killed by a tiny pellet of a substance called Ricin.

He was Bulgarian. He took refuge in London and worked as a broadcaster in BBC. He criticized the Bulgarian communist regime. It is believed by many that this lead Bulgarian government to seek KGB's assistance in silencing him.

On September 7, 1978 he developed high fever and was admitted to the hospital. He died in three days. The cause of death was not clear. Before his death, he recalled an incident, which was key to unraveling this successful assassination attempt.

He was waiting at the bus stop near the Water Loo bridge when he felt a stinging pain in his legs. He turned and saw a man pick up his umbrella and apologize. He (probably) ignored it. But, by the time he realized that it was no accident, it was too late.

He died on September 11, 1978. During his postmortem investigation, forensic pathologists discovered a spherical pellet the size of a tiny pin-head. The pellet had two holes the size of 0.35mm drilled into it. Traces of Ricin was was found in those holes.

Ricin is a toxin. According to FBI, it is one of three most dangerous substances on Earth. It is perhaps the most easily available bioweapon.

Ricin is a protein found in the castor plant (Ricinus communis), the one from which we get Castor oil. This grows in almost all tropical countries. The toxic effects of castor seeds are well known.

Ricin is a very powerful cytotoxin. It belongs to a group of toxins called Ribosome Inactivation Proteins. Ricin is a Type 2 RIP. That is it has 2 poypeptide chains - one to bind to the cell membrane and the other to enter the cell and inactivate the ribosome.

The RTA chain of this heterodimeric protein gains entry into the cell with the help of RTB chain. Once inside, the RTA (a 267 residue long polypeptide) exhibits its N - glycosidase activity by removing A4324 in the 28S rRNA of 60 S subunit of the ribosome. Removal of this prevents the binding of elongation factors. This halts protein synthesis. The cell ultimately dies.

The toxic effects of this protein may develop as soon as within 2 hours of exposure. The symptoms of the ricin poisoning varies with the system that is exposed. It is quite difficult to zero in on the toxin very easily.

There is no vaccine for the protein. There is no direct cure. It is easily available and it is not that difficult to spot Castor plant in any country!!!

All these make it the most efficient bioweapon candidate. And, the 'umbrella murder' Georgi Markov brought the tropical toxin to the lime-light.


. Thursday, May 17, 2007

Here is another video on translation. Its amazing how a process can be viewed by different people in different ways. Well, as long as their imagination adds beauty to the actual process, I am thankful to the creator.

Nano in the Eyes

. Wednesday, May 16, 2007

At John Hopkins, researchers have developed a nanoparticle as a new biosensor to treat damaged retinal cells.

Biosensor detects oxidative stress inside the cells. It responds by regulating therapeutic gene expression. This reduces the damage caused by the free radicals.

Biosensor has an outer lipid layer. This layer also has some targeting proteins. These proteins recognize the endothelial cells lining the eye's blood vessels. The lipid outer layer ensures easy entry of the biosensor into the cell.

Once inside the cells, the DNA is exposed. If there is oxidative stress, the promoters are activated and two proteins are expressed. One, a fluorescent protein that helps in detection of the damaged cells; two, a therapeutic protein that reduces the damage.

They have tested the biosensor in animal models like mouse, rabbits, and dogs. These nanoparticles were also found to be nontoxic on cells but animals showed varied levels of toxicity.

You will find more info here.

why family

. Monday, May 14, 2007

If there is one change i want to bring about in the indian society, it would be to eliminate family system.


. Saturday, May 12, 2007

What an amazing video!!! This is one of the most spectacular videos I have come across that shows Life so beautifully that you just can't help but fall in love with it!

Oh yes! I'm talking about life inside the cells!!!!

Too desperate to get lucky!!!!

. Thursday, May 10, 2007

Luck!!!!! How strange it is!!! You try very hard to convince yourself that it does not exist. But, its simply not possible for you to ignore its apparent presence in every aspect of your life. Or so your lazy 'self' tends to believe.

I find myself in a state where I am just too desperate to get lucky. In definite need of some good luck...

Why would one need luck??? As far as my understanding goes, there can be two reasons: 1) You deserve to succeed in all ways and a bit of good luck would make your chances of winning a perfect 100%.
2)You have nothing that can get to the gates of victory and you need some good luck to get you there!!!
Now, if you know me, you will have no doubt which of the above reasons suits me best.

My observation of luck for the past 21 years is that it can be really tricky. Its too elusive when you look for it. You just ignore it, you will find yourself surrounded by it.

I wonder whether I am too desperate to get lucky!!!!

Translation Animated!!!

. Wednesday, May 9, 2007

Here is something I found on you tube! An interesting way of looking at the process of translation. Especially the aminoacyl tRNAs enter the ribosomes... Post transcriptional modifications were not given here. However, its a great piece of animation.

Flying Nano Wonders!!!!

. Tuesday, May 8, 2007

Butterflies are probably the most beautiful creatures on earth. Those colorful wings captivates you with its beauty.

Have you ever thought whether those magical patterns are formed by true colors??? In fact, these clever insects trick you into believing that their wings possess true colors. The wings have what can be called biophotonic crystals that scatter light in some intriguing ways. Something our 21st century physicists have hard time replicating in labs!

These are some ridges of nano dimensions found on the surface of the wings. These creatures have been exploiting the potentials of nanotechnology for the past 30 million years!!!!

What you see here is not some fabric... but the wings of a butter fly.

I found more details about this here. You may want to take a look at this site!

Fwd: Hmmm!!!!!

. Monday, May 7, 2007

Interesting!!!! Its interesting that I was not able to sign into this site...
Anyways, this gives me a perfect opportunity to test something! Posting through email. Let me see if it works....

Now, coming to the actual post...

Viroids were discovered very recently but they are believed to be present here on earth for as long as life itself! This was because of the fact that some of them exhibit hammerhead ribozyme activity.
They also have interesting way of replicating.......
I came across a mini review of viroids at . The paper was published in Febs Letters, volume 567, Issue 1, on 1st June 2004, Pages 42-48 .
Here is the link.


Virus - Proteins

. Saturday, May 5, 2007

Viroids are strange infectious agents. Intriguing and very interesting!

These are nothing but a piece (often a small one) of circular single stranded RNA. These viroids are just 250 to 500 bases long. What makes it interesting is the fact that they like prions defy the concept of cellular organisation!

These RNAs replicate by Rolling circle model of replication.

They are capable of infecting cells and cause diseases.
Many plants diseases are now known to be caused by various viroids.

These are found to exibit catalytic activity as well. Catalyses reactions like forming or breaking covalent bonds.

The only (?) human disease caused by viroids is Hepatitis D...

RNA interference

. Friday, May 4, 2007

Hi there! Here is something you will definitely like. The concept of RNA interference is explained in this video, I found in YouTube, very beautifully!!!!

. Thursday, May 3, 2007

If there is something in this world that never ceases to fascinate me is DNA. Especially, the fact that 6 ft of DNA is coiled into a compartment thats less than 3micrometre diameter. I found this amazing video on youtube. Enjoy!!!!!!