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The Mutation of Fibroblast Growth Factor Receptors and Achondroplasia
The fibroblast growth factors (FGFs) and their receptors are very important in cells growth and differentiation. The mutation in fibroblast growth factor receptors (FGFRs) result in many genetic disease. Achondroplasia is one of the most common forms of human dwarfism; it is also associated with the mutation in the FGFR3.

The activation of tyrosine kinase receptors is created by two main steps. The first step is the binding of FGFs to their receptors cause the receptors to aggregate, forming adimer. In the second step, the tyrosine kinase is activated by the eggregation from step one; the phosphorylation will occurs between the tyrosine kinase and its neighbors, phosphates are added to tyrosine on the tail of the other polypeptide. The signal will be initiated; the protein is now activated. One tyrosine kinase receptor dimmer will be able to activate ten or more different intracellular proteins simultanteous. There are three main signals. The first one is the activation of the ras G protein and the MAP kinase cascade to signal to the transcription DNA. The second one is the activation of phospholipase C to make the separation of PIP2 into IP3 and DAG. The third signal is the phosphorylation of Stat1 transcription and its subsequent translocation into the nucleus. In the activation of the FGFRs, heparin has been found to have effects on the biding of FGFs to their receptors. It will help the FGFs binding together as a web and link to their receptors.

There are many types of FGFRs in human body and also there will bee many types of FGFRs mutation in our body. In this article, there are three first FGFRs introduced such as: mutations in FGFR1, FGFR2 and FGFR3. Mutation in FGFR1 can cause the Pfeiffer Syndrome, a malformation syndrome, leads to the abnormal of skull and facial shape. Mutation in FGFR2 may cause three different type of syndrome such as Crouzon Syndrome, Jackson-Weiss Syndrome and Apert Syndrome. Mutation in FGFR3 can give Achondroplasia or Thanatophoric Dysplasia. The most common forms of achondroplasia are found with a very high percentage (97%) specific to FGFR3 mutation in the transmembrane of the receptors. In a normal condition of the transmembrane region of the protein, Glycine amino acid is found on DNA at the position 380. But in the mutation FGFR3, there is the absence of glycine; and at that location, there is an appearance of arginine. This is the results of a genetic mutation of glycine to arginine.

The achondroplasia is caused by the mutation in FGFR3 as the “gained-of-function” mutation because the FGFRs gain their activeness. Usually, the binding of the FGF to the FGFRs will help the FGFRS becoming more active. But in the mutations of FGFRs, the FGFRs are able to be more active without binding to the FGF ligands. The FGFRs has been gain the function of the Stat1 transcription factor and its subsequent translocation into nucleus. This is the third type of signaling. Under the effects of gaining the function of Stat1 transcription factor, the more signaling of this function is the more the cell cycle is limited and inhibited, leads to the cell growth arrest. This is how “gain-of-function-mutation” affects the growth of the affected individual.

The FGFRs and FGFs relate to achondroplasia as the mutation in FGFR3. Furthermore, the mutation in FGFRs is responsible to many diseases. FGFs and FGFRs have an important position in cell growth and differentiation.

Referrence
http://ghr.nlm.nih.gov/gene/FGFR3 http://www.pnas.org/content/101/2/609.full.pdf

Ocean Fertilization
The Earth has been warmed up by CO2 produced by human activities. The amount of CO2 has been increasing in our atmosphere. The scientists discover one way to decrease the concentration in atmosphere, which is ocean fertilization. In the article “Dis-crediting Ocean Fertilization,” the authors refer to the ocean fertilization with its affect on global ocean and the possibility of trading credit for carbon sequestration. The cycle of carbon is like the cycle of photosynthesis and aerobic metabolism; in which the CO2 produced by human is converted by phytoplankton on the surface ocean. The carbon sequestration and ocean fertilization help to lower the concentration of CO2 in the atmosphere but they also cause some problems about global ocean such as damaging the food webs. The articles talks about a big picture of ocean fertilization and the problems about it, but through the article, the authors seem to want to mention about the cost/benefit analysis of ocean fertilization. They want to say that “dis-crediting ocean fertilization.”

The article comes up with the issues about fertilization and the global market. First of all, the authors introduce about the ocean fertilization and carbon sequestration. Carbon sequestration is long term storage of carbon in the ocean; the storing of CO2 concentration in atmosphere will reduce or slow. It includes the ocean fertilization. In ocean fertilization function, the phytoplankton is very essential; it is the single-celled organism known as microscopic marine plants that converts CO2 to organic carbon in the surface ocean. The phytoplankton uses CO2 for photosynthesis. The more amount of phytoplankton, the more CO2 is pulled from the atmosphere. Some of the organic carbon is generated to CO2 and some of them sink to the deep sea. The organic carbon is stored in the ocean. The ocean fertilization is also known with iron dusting. In the surface ocean, the phytoplankton biomass is small; it will be able to use the excess amount of N and P in the surface ocean because of the scarcity biologically available iron in these high-nutrient and low-chlorophyll (HNLC) regions. The dust from land contains big amount of iron for the sea. The scientists note that dust and CO2 have an inverse relationship: dust is high, CO2 is low. Or we can say that dust and CO2 converted have a direct proportional relation ship: when the dust is increasing, the resource of iron is big; the CO2 converted into the deep sea is more. So, we also can increase the amount of iron by fertilizing the iron for the sea; by this action we can decrease the CO2 in atmosphere but it also cause many problems for the ocean. Ocean fertilization helps to lower the atmospheric carbon dioxide and the average temperature by using thy photosynthesis of phytoplankton.

The ocean fertilization can be used in large scale and small scale. In the small scale, the small amount of iron is added to water to cause the increasing phytoplankton productivity and massive growth in a short period of time such as a few days to weeks. The scientists show that the biomass of phytoplankton has been increased. So many groups of scientists are working separately to research for this process. In the large scale, ocean fertilization may cause to change the ecology of the oceans and the food webs. The ocean fertilization gives the benefit to decrease the atmospheric CO2 and average temperature but it also brings up two main problems such is change in the global ocean and the global market of trading credits for carbon sequestration. There is the existence of conflicting about ocean fertilization. The proponents think that the ocean fertilization is easily to control and it mimics nature. But these thoughts seem incorrect. First of all, the ocean is not easily controlled. We have only one ocean connected around the world. In addition, it does not mimic nature. In ocean fertilization, iron would be delivered to ecosystem at rates that do not mimic. To put ocean fertilization as a carbon sequestration option into perspective, there is two question to ask such as why CO2 increase in the atmosphere and how sequestration to mitigate this rise. These two questions seem related to the aerobic metabolism and the photosynthesis. There is two basic carbon cycles operate on Earth. In the first cycle, volcanic outgassing drives coupled to metamorphic weathering of silicate rocks, this cycle operates on time scales of millions of years. The second cycle is the oxidation of CO2 to organic matter and the oxidation of organic matter by respiration. This may cause to form fossil fuel. When human burns fossil fuel, the carbon is brought from the slow cycle back into the atmosphere. The ocean fertilization brings the benefit to help converting the CO2, but it also can be damaging the global ocean.

Through the article, the authors are talking about the ocean fertilization but they want to make the point about the problem around its. They show the readers the real situation is that we are facing with the increasing of CO2 in the atmosphere. The ocean fertilization may help us to lower the CO2 but it also causes some effects on the global ocean. The ecology of ocean may be damage and the credits for carbon sequestered may be traded. The scientists keep researching about ocean fertilization and carbon sequestration, but we also facing with the carbon trading. The authors think that we should not trade it. This may cause more problems around the ocean fertilization. In this article, the authors hold the view that a cost/benefit analysis weighs heavier than the method of ocean fertilization. Because during the article, they do not show the readers how is the iron dusting helps to increase the growth massive and decrease the CO2. They also do not talk about how the ocean fertilization may cause the damage global ocean although they mention about it several times. This article generally introduces about ocean fertilization but does not talk deeply about the specific methods and processes.

The ocean fertilization can help us to decrease the CO2 in the atmosphere, but it also cause many effects on the global ocean and the ecology. We need to use this function correctly and consequently. Ocean fertilization should never become eligible for carbon credits.

References

http://www.sciencedaily.com/releases/2007/11/071129132753.htm http://www.sciencemag.org/content/294/5541/309.short http://www.sciencemag.org/content/300/5616/67.short