#1 Fundamentals of Chemotaxis | Signaling Pathway in Bacteria, Inflammation

Pratik Ghadge
5 min readDec 23, 2020

Now, in this blog, we will have a detailed look at Chemotaxis in bacteria and the signaling pathway in chemotaxis.

We know, when there is only a beneficial substance like nutrients that acts as attractant near the bacterial population the bacteria will go towards it, and on the other hand when there is any toxic substance that acts as a repellent in its vicinity.

The bacterial population will go away from it so this is how the chemotaxis works in bacteria but how this attractant and repellent are censored within the bacteria will be shown in the following signaling pathway the chemotaxis pathway is media through a transmembrane protein called MCP.

Contents hide

1 What is MCP? (Methyl-accepting Chemotaxis Protein)

2 Chemotaxis Process in Plants, Bacteria and in Eukaryotic Cells

3 The 2 Different Types of Chemotaxis Process

4 Chemo tactics features in Eukaryotic Cells

5 Ligand Receptor Binding?

What is MCP? (Methyl-accepting Chemotaxis Protein)

Methyl-accepting chemotaxis protein it’s a receptor protein that is able to detect the repellents and attractants in the environment prior to ligand binding the receptor is in the form of monomers and when there is any substance a repellent near the bacteria.

The repellent acts as a ligand for the MCP receptor as you can see in this diagram the repellent acts as a ligand for the MCP receptor and shows ligand-binding activity towards this receptor the binding of the ligand towards the receptor is followed by the dimerization of MCP.

So, now the MCP has got conformational changes in its structure which means it has got activated by a ligand so after dimerization of MCP.

The MCP recruits two more proteins one is called TW or you can say CW protein and another one is G a protein or you can say C a protein the CW protein only acts as it turns to sir protein for the signal to be transmitted to see a protein and it is this C a protein which acts as a sensor kinase.

The CF shows kinase activity and Auto phosphorylates its hysteria residues after the autophosphorylation of GA protein the GA protein activates the protein by transferring the phosphate towards the aspartate residue off Gy and finally the G whey protein postulates.

The protein complex composed of three proteins FL I am FL IG and FL I am this protein complex acts as a pledge learn more to switch and when this Chiba protein activates this switch it gives signal to basal body of the flagella to switch the rotation for direction change and in this case the ligand was repellent.

So, the rotation of flagella will be switching from counterclockwise to clockwise rotation to get away from the substance that’s toxic for a bacteria.

Now, let’s see the movements in bacteria depending upon the substances which bacteria encounter, first of all, we see bacteria show forward movements in presence of nutrients and at that time.

The flagellum rotation is counterclockwise that means the bacteria is going forward but when there is the presence of any toxic chemicals in its vicinity the counter-clockwise movement will be switching to the clockwise rotation of the flagellum and the bacteria will go away from that substance.

This is all about chemotaxis in bacteria lets continue to learn more about its process in plants and eukaryotic cells.

The 2 Different Types of Chemotaxis Process

Now, in this case, there are two types of chemotaxis possible one is that the cell is attracted towards the chemical molecule right this kind of chemotaxis is called chemoattraction right? chemo addiction or chemoattraction now in this schema attraction.

This is also called a positive kind of chemotaxis but there is another kind of chemotaxis, possible I imagine the situation where there is certain chemical molecules chemical signal for signaling molecules that are present out there are acting as a repellent for that cell.

So, again, in this case, there is a cell it can be unicellular or multicellular whatever now that cell due to the presence of those chemical factors one to go away from those chemicals a cell is present in the environment but as slowly certain chemical molecules start to surround that cell it kind of distract the cell and cells start to move away from that chemical molecule this is called Chemo Repellant Feature.

Chemo repellent or negative form of chemotaxis this is chemoattractant or positive type of chemotaxis so these are the two types of chemotaxis that are possible okay based on that track activity either it will be attracted towards the chemical molecule or it is going against going away from that chemical molecule in either way this is chemotaxis.

Because definitely the movement of the cell is driven by the chemical molecule living by the concentration of chemical molecule that is present outside that cell.

Now, there is an example for both this scenario right if we choose unicellular organisms like bacteria in that case we know there are certain chemical molecules that attract that bacteria that can be a food source, a simple example for chemo tactics is a food source.

So, if there is a food source that food is acting as a chemical molecule and that is attracting the cell the bacteria to move towards the direction of the food to take that and bacteria will go to take that food because it is necessary on the other hand if there is any kind of toxin that is present in the environment in that case bacteria one to go away from that toxin.

So, it is a chemo repellent type of chemotaxis in case of toxin right they will go away from toxin they will try to go away from a toxin that is the chemo repellant feature of it now generally this process of chemo Texas is widely observed in case of bacteria and it is necessary for setting up different infections in our body during the different stages of bacterial invasion.

Chemotaxis Process in Plants, Bacteria and in Eukaryotic Cells

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Originally Published at https://bingeexpress.online

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