Microbes and the Human Body (Essay Sample)

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Microbes and the Human Body
1) Describe structure and function of a two-component regulatory system and its use by Yersinia pestis during host infection.
In terms of structure, a two-component regulatory system has histidine kinase (such as EnvZ) that has been bound to a membrane. During host infection, Yersinia pestis uses histidine kinase to sense and respond to top environmental changes. One of the ways in which this microorganism responds to ecological changes is adaptation. Typically, adaptation response comes when a microorganism has been repeatedly subjected to unconducive environment ( Resch et al. 16). The micro-organism opts to adapt to this kind of environment because there is no other place to escape to. The other way in which the microorganism responds to environment is growing. This is especially when the host environment has been adjusted in such a manner that it creates perfect conditions for growth. Presented here below is an image illustrating the structure of a two-component regulatory system
2) Explain Robert Koch’s postulates. Describe a situation where they might not provide a clear diagnostic conclusion.
Robert Koch’s first postulate that bacteria must be in every disease implies that the leading causes of many diseases is bacteria. What Robert is trying to suggest in this case is that healthy individuals lack disease-causing bacteria. The best way to escape diseases as per this postulate is to avoid bacteria. One of the ways in which this is possible is avoiding substances or environments that contain the bacteria. Taking water that for instance, contains Vibrio cholerae bacteria will contribute to cholera disease (Neville et al. 47). To avoid suffering from cholera, the best thing to do will be to take clean water that does not contain the bacteria. 
The postulate that bacteria have to be isolated from the host and then cultured implies that bacteria can grow in an artificial environment that offers survival conditions similar to those offered by the body of a host. Typically, bacteria that are being cultured grow at a high rate when compared to that which is in the host environment. One reason for this is that the host environment is designed to fight disease-causing microorganisms. The process of fighting the bacteria contributes to a low rate of growth due to death of some bacteria (Neville et al. 47). Cultured bacteria are provided with the perfect conditions for growth hence the fast growth. 
Robert’s postulate that cultured bacteria will always cause disease whenever they are introduced to a healthy host means that growing bacteria through culture does not alter their ability to cause disease. Culturing bacteria does not cause any form of alteration because this process only creates a perfect environment for growth. The process, for instance, provides a conducive growing temperature. Typically, bacteria die in a case where they are subjected to an environment that they cannot survive. The other way in which the process provides a conducive environment is through ensuring enough substrate for the bacteria. The postulate also confirms that bacteria are the leading cause of diseases (Neville et al. 47). The image below illustrates all of Robert Koch’s postulates.