"I eat therefore I am"; globalized agriculture

Agriculture and soil. Pollution control, soil remediation, humus and new agricultural techniques.
dedeleco
Econologue expert
Econologue expert
posts: 9211
Registration: 16/01/10, 01:19
x 10

epigenetic basis of multicellular life




by dedeleco » 16/03/12, 19:48

the minimum to know:
http://fr.wikipedia.org/wiki/%C3%89pig% ... C3%A9tique
http://en.wikipedia.org/wiki/Epigenetics


Without having identified the carriers of these transmissible modifications, human studies (study of the weight of the newborns during the famine in the Netherlands in 19479, as well as their descendants), Drosophila (larvae subjected to high temperatures ) 10 showed the influence of the environment on the diversity of life.

A study of a population of which all individuals were referenced as well as their diet according to harvests showed thata grandmother who has experienced a famine transmits this information to her offspring and therefore modifies the DNA of her grandson, who can develop illness when he has never experienced famine

Similarly,Pregnant women during the September 11 2001 events showed that the child had higher cortisol levels12.

This phenomenon would imply that some diseases are not due to a variation of the DNA sequence but perhaps to epimutations. Epigenetic mechanisms would be new targets for the development of specific drugs. While waiting for this confirmation, we can already reconsider our heredity and defend the idea that we are not just the product of our genes.

Epigenetic therapies

There are currently few therapies acting directly on the epigenome. Many are under study in clinical trials or have been approved for specific types of cancer.

Nucleoside analogs such as 5-azacytidine are incorporated into the replicating DNA. They inhibit the methylation of DNA and reactivate silent genes. 5-azacitidine has been shown to be effective in phase 1 clinical trials in the treatment of myelodysplastic syndromes and leukemias, sites of gene hypermethylation.
Indirectly epigenetic therapies

An indirect intervention on the epigenome consists in modulating the availability of the methyl groups. To do this, it is possible

to vary the concentrations of cofactors transporting the methyl groups (more commonly cobalamin (vitamin B12) and folic acid13,14, but also choline and trimethylglycine, betaine) or
to intervene on xenobiotics and other factors known to have an impact on methylation. These treatments are most often preventive,
to counter oxidative stress, recognized for its negative impact on the epigenome.
to reduce homocysteine ​​levels,
to modulate the availability of the methyl groups by intervening on their incorporation into the acceptors of methyl groups other than DNA, in particular the phospholipids of the 15,16 cell membranes.

It has been proposed that vitamin B12, folic acid, DHA, as well as oxidative stress have a role to play, through epigenetic modifications, in the alterations in neurogenesis observed in premature children.




to rough the question:
uh, it puts you in full details of the vocabulary, then crucial Nobel Prizes, then cancer
http://epigenome.eu/fr/1,38,0
http://epigenome.eu/fr/1,3,0
http://epigenome.eu/fr/1,7,0

a small summary of all the genetics then of the real epigenetics, to finish in the researches on what constitutes all the multicellular life, with secret codes which remain to be discovered of which one has only fragments, infinitely complex to decipher, by report to a tape recorder that reads.
It is certainly a mechanism participating in the evolution of living beings;

to finish in serious scientific reality:
clear precise definition very vast, study of any inheritable change or that is transmitted without being due to a change of the DNA sequence of the genes, so very vast and which is practically all that differentiates our life from being multicellular of the monocellular as bacteria, and therefore the very structure of our life. :

Epigenetics is typically defined as the study
of heritable changes in gene expression that
are in the DNA sequence.
Diverse biological properties can be
affected by epigenetic mechanisms: for example, the
morphology of flowers and eye color in fruitflies.


http://www.nature.com/nature/journal/v4 ... 47395a.pdf
http://www.nature.com/nature/supplement ... index.html

A fundamental effect of epigenetic memory without changing the genes and their DNA:
Epigenetic 'Memory' Key to Nature Versus Nurture
http://www.sciencedaily.com/releases/20 ... 135553.htm
http://www.nature.com/nature/journal/v4 ... 10241.html
essential to all farmers and arborists:

ScienceDaily (July 24, 2011) - Researchers at the John Innes Center made a discovery, reported this evening (24 July) in Nature, that explains how an organism can create a biological memory of some variable condition temperature. The discovery explains the mechanism of this memory - and it can also be inherited by offspring.

The work was led by Professor Martin Howard and Professor Caroline Dean at the John Innes Center.

Professor Dean said: "There are quite a few examples that we now know of where the activity of genes can be affected in the long term by environmental factors. And in some cases the environment of an individual can actually affect the biology or physiology of their offspring but there is no change to the genome sequence. "

For example, some studies have shown that in families where there was a severe food shortage in the grandparents' generation, the children and grandchildren have a greater risk of cardiovascular disease and diabetes, which could be explained by epigenetic memory. But until now there hasn't been a clear mechanism to explain how individuals could develop a "memory" of a variable factor, such as nutrition.

The team used the example of how plants "remember" the length of the cold winter period in order to exquisitely time flowering so that pollination, development, seed dispersal and germination can all happen at the appropriate time.

Professor Howard said: "We already knew quite a lot about the genes involved in flowering and it was clear that something goes on in winter that affects the timing of flowering, according to the length of the cold period."

The team has a key to the problem of a gene called FLC, which is either completely or partially in place. They found that FLC stably flipped to the off position. This delays is known to epigenetic memory.

Epigenetic memory comes in various guises, but one important form involves histones - the proteins around which DNA is wrapped. Particular chemical modifications can be attached to histones and these modifications can then affect the expression of nearby genes, turning them on or off. These modifications can be inherited by daughter cells, when the cells divide, and if they occur in the cells that form gametes (eg sperm in mammals or pollen in plants) then they can also pass on to offspring.

Together with Dr. Andrew Angel (also at the John Innes Center), Professor Howard produced a mathematical model of the FLC system. The model predicted that each individual cell, the FLC gene should be completely isolated or completely silenced, with the fraction of cells switching to the increasing silenced state.

To provide experimental evidence to back up the model, Dr. Jie Song in Prof. Dean's group used a technique where the FLC gene was switched on, shown up under a microscope. From her observations, it was clear that cells were either completely switched or not at all, in agreement with the theory.

Dr. Song also showed that the FLC gene has been modified during the cold period, in such a way that it would be accountable for the switching off of the gene.

Funding for the project came from BBSRC, the European Research Council, and The Royal Society.

Professor Douglas Kell, Chief Executive, BBSRC said: "This work not only gives us insight into a phenomenon that is crucial for future food security - the timing of flowering according to climate variation - but it uncovers an important mechanism that is at play right across biology. This is a great example of where the research that BBSRC funds can provide not only a focus on real life problems, but also a grounding in the fundamental tenets of biology that will underpin the future of the field. It also demonstrates the value of multidisciplinary working at the interface between biology, physics and mathematics. "



To live a long time it is enough that your ancestors live so long by an epigenetic trans generation mechanism:
Transgenerational epigenetic inheritance of longevity
http://www.ncbi.nlm.nih.gov/pubmed/22012258
0 x
Christophe
Moderator
Moderator
posts: 79117
Registration: 10/02/03, 14:06
Location: Greenhouse planet
x 10973




by Christophe » 20/04/12, 18:13

Another documentary (with many others) on the subject of global agriculture: https://www.econologie.com/forums/l-europe-e ... 11742.html
0 x

Back to "Agriculture: problems and pollution, new techniques and solutions"

Who is online ?

Users browsing this forum : No registered users and 359 guests