Tag Archives: Biology

Gibberellin a plant growth hormone.

I was readding an Asimov’s book about the brain and he came to growth hormones in plants. First he talk about Auxins and later about Gibberellins. He says about Gibberellins:

“Sprayed upon plants, it encourages a too rapid and too disorganized growth, killing them, trougth what practically amounts to an induced cancer”.

It was so interesting that I needed to learn more. So, first stop, PubChem for a view of 3D structure and some data. (If you want to get fast info about molecules or proteins, PubChem is a very nice place with cool graphs and lots of data, so, please, take a look).

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To learn something on what is Asimov talking about, we need to review somethings.

Cancer is when cells grow without control, and a such rate that cells in the end tend to die and accumulate into other places making other cells to also die or making imposible for them to work. (I’m not biologist, so that’s the best I can say).

Point two. Aminoacids are structures of between 10 and 30 atoms. Proteins are structures made of aminoacids, usually have from 1000 to 1000000 atoms. Such huge amount of atoms is quite dificult to study, and many groups are working quite hard to develop new techniques to understand how proteins fold (thanks to Ludovica for introducing me to this fascinating world ;) ).

Part three. Hormones are a especial tipe of proteins that a living organism uses to comunicate different parts of the body or trigger some mechanism. Enzymes are other kind of proteins which task is to destroy, specifically, other proteins.

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(Human enzyme glyoxalase I.)

How they work together?

The common scenario is that a glandula (an part of the body where hormones are produced, we have many), recives the order to produce some kind of hormone.  For example, the amount of sugar in the blood triggers the production of insulin in the pancreas. Once liberated, the insulim helps to sintetice the sugar into other compounds. If the sugar level is too high, the pancreas can read it’s level, and a enzyme called glucagon is produced and it compensates insulin raising sugar level.

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And what have to do Gibberellin in this?

Gibberellin is an growth hormone for plants. That means that its the way plants transmit the message “grow” to different parts of their body. But it’s not the only one. Other hormones are Auxin, Citokinin, Abscisic acid and ethylene gas.
(Thanks to: http://www.biologie.uni-hamburg.de/b-online/library/plant_physiology/Seedgerm.html )

hormones

Each of then is generated in different parts and control the growth of the plant. For example, Auxin is created mostly in the stems, can controls elongation, and can be destroyed by solar rays. So… if we have a stem inside a box and the sun enters in one of the sides of the box, the Auxin in this side is going to be destroyed, while in the other side makes the plant grow… and blend the stem towards the sun… That means… a mechanism to grow towards the sun!

And what Gibberellin controls?

Well it changes a little bit from plant to plant, and also depending on the growing state of the plant, but among the things that this hormone controls, the most important one is the Growing speed of seeds.

So… that means that if the levels of Gibberellin inside the plant are raised, than the plant can grow bigger. And if they rise enough, the growing becames uncontrolled and then cancer appears.

Biology is cool. But much more. Did you know that Gibberellin can be synthesized artificially? And actually is a very common aditive in many farms to make plants and fruits grow bigger.

Ok, cool good, we get bigger food. and what about the cancer? Well that’s the interesting point. if you see the whole video lesson, we can understand that obviously we are tackling the limit of a very delicated order, and if we go too far cancer appears, but if we learn how to compensate overgrowth, we can still have bigger plants and make them healthy!And that’s where theoretical biology, numerical simulations biology and experimental biology enters. And it’s going to be (it’s not finished yet) an amazing voyage.

So.. thanks biologist for all this things. And thanks Asimov once again to point to another interesting thing.

To read about japanese farmers and how Kurosawa discovered the Gibberellin, go here.

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