Need a unique essay?
Order now

Essay Sample on Antimicrobial Peptides

7 pages
1844 words
George Washington University
Type of paper: 
This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

The microbial peptides are well-diversified molecules which naturally occur in a multicellular organism and during an immune reaction they are released as the first line of defense. The reaction results in the killing of viruses bacteria fungi, and in some cancers the cells related to cancer. The plants and insects secret the microbial peptide to protect against potential pathogenic attacks, but the microbes secret the same to safeguard their niche within the environment. The eukaryotes in the higher rank in the environment produce the same in the form of immunomodulatory activities that protect against the potential disease causative agents. For instance, in a human being the actions that are produced by the cytokines in the immune system are a good example of the antimicrobial peptide action that ensures pathogens do not affect the host (Zhang, Rozek, and Hancock, 2001 p15). These elements are also referred to as immune homeostasis since they help to regulate the immune systems of the various organism in different habitats. Additionally, the inappropriate expression of the antimicrobial peptides may be induced the autoimmune diseases. These diseases occur as a result of miscommunication within the body and immune responses, as the work elements attack the body. The APA, essentially accumulate at a site with infection and launch their action to protect the body from harmful outcomes. Their reaction is facilitated by their strong attraction through the electromagnetic charges towards the pathogens such as the bacteria which are negatively charged. The host cells are also charged but to ensure the antimicrobial peptide activities do not harm the host; there is a weak attraction which does not encourage the contact between the two (Ebenhan, Gheysens, Kruger, Zeevaart, and Sathekge, 2014 p5). Therefore the antimicrobial peptide action shift towards the direction for the pathogen and destroys it making the body safe. When the action is boosted by conventional medicines the peptides works faster and with vigor to eliminate the potential threat. The paper shall focus on the actions of the antimicrobial peptide on various situations in dealing with pathogens.

The scientists have been able to uncover three categories of the antimicrobial peptide (AP) which include, the flexible AP, a-helica AP, and b-sheet AP. The a-helica AP represent the largest groups of these elements representing between 30 and 40% of all AP available. They have a-helica shape and chemically made up of between 12 and 40 amino acids and has many helix residues to promote its stabilization, for instance, the alanine and lysine (Ebenhan et al., 2014 p7). When the AP is in an aqueous solution, the molecules losses their structure but forms an amphipathic a-helica shape which appears like a cell membrane. However, the a-helica AP may sometimes have an internal kink. The second major category of the AP is the b-sheet, which has between two and ten residues of cysteine that forms a long chain of disulfide bonds. These long chains are the ones responsible for the b-sheet shape that characterizes these AP and therefore their names. Most of the b-sheet AP are confined within vertebrate animals, plants, fungi, and mollusks among other organisms. They fall in the defensins family, which AP consisting of around three parallel are running to each other a disulfide bond helps to stabilize the structure by running intramolecular. When the b-helica peptide is placed in an aqueous solution, they maintain a compact globular structure. This is also considered the mager difference between the a-helica and b-helica. Finally the last category of the flexible AP which contain a volume of particular amino acids which include histidine, glycine, and proline among others that help determine its structure and chemical nature. This also helps to determine the kind of threat it can address and which part of the body. When either of the three categories of the AP is set to respond pathogenic attack, the working mechanism is based on the chemical nature of the peptide and the chemical and the structural nature of the host cell membrane. This form of regulation is to prevent unwanted autoimmune reaction with the vulnerable host cells. For instance, the immune system uses the hydrophobicity, and the charge of the cell to detect the appropriate peptide and in what concentration to avoid stray peptides in the body that may lead to unexpected harm to the host. The membrane symmetry between that of the host and microbial organism helps the AP to improve its targeting for a particular pathogen. For instance, they can use the saturation of the phospholipid layer to identify the pathogen as it passes through the body cells (Ebenhan et al., 2014 p10). The microbial cell membranes also have a stoichiometry that allows them to changes their surfaces and this movement can be detected by the AP and hence induce an immune reaction. These changes are due to the fluidity which is different in both microbial and human cells which improves the chance of establishing the location of a pathogen.

Therefore the adaptive immunity is critical in preventing the microbial action while the innate immunity is responsible for initiating the action against the microbes. The pathogen has undergone evolution, and for this reason, the AP has evolved too to be able to counter the pathogenic action. The co-evolution is to ensure there is a balance to avoid the immune system working on an updated pathogen with an outdated mechanism (Phoenix, Dennison, and Harris, 2013 p2). This is the reason the different type of peptides have to reorganize their chemical structures to enable them to counter the microbes of a different kind (Sanchez, Martinez, and Maffia, 2013 p4). The process for updating the chemical nature of the defense of the AP is the proteolytic process which fashions the peptides according to the pathogenic threat. However, some peptides are readily available in the body eating for pathogen some are synthesized immediately the microbial is detected by the immune system. This is the reason why peptides are sent to accumulate in an area with infection to improve the efficacy of the body to destroy the pathogen. Alexander Fleming was the first person to discover the first AP in human beings in 1922 (Zhang and Gallo, 2016 p15). The discovery improved when in the 1940s he discovered penicillin which won him a noble price award in 1945 for in an antibiotic which was a gold award in the field of medicine (Cezard, Silva-Pires, Mullie, and Sonnet, 2011 p12). This discovery shadowed the therapeutic efficacy of the AP and people started to endeavor in scientific discoveries to establish more treatments for microbial diseases.

Additionally, the AP is considered tumoricidal and mitogenic which enables them to fight the cancer agents. This is based on their capacity to interact with both the cationic and anionic cell membranes. In this respect, the tumor cells have a strong electromagnetic attraction to the cationic side of AP which also have strong anionic phosphatidylserine elements which also makes it a reliable agent for fighting tumors. However, not all AP have antitumor properties as various AP are designed to address particular microbial or pathogenic agents. For instance, the AP such as magainins melittin, and defensins are specialized for this function. This means that even in the face of a mutation of the same cancer-causing agent, the AP will be able to modify itself and reorganize its chemical structure and work to eliminate cancer cells such as melanoma and carcinoma. However, a higher concentration of the AP is required to counter the action of the tumor causing cells. Studies have shown that cancer-causing agents develop at a rapid rate that the body can control and therefore a high concentration of these immune cells are required to control the situation (Pushpanathan, Gunasekaran, and Rajendhran, 2013 p12). This means that the cells have to regenerate faster than the rate at which the cancer cells are proliferating in the hosts body. Unfortunately, the tumouricidal cells have a sophisticated extracellular matrix which has protease. The protease can denigrate the AP which comes to its contact this reduces the efficacy of the antitumor AP.

After the discovery of Penicillin, scientists shifted their focus from the therapeutic nature of AP to antibiotics. Unfortunately the microbial started to develop resistance, and hence the focus shifted again to the effectiveness of AP to deal with bacterial and other causes of disease (Mahlapuu, Hakansson, Ringstad, and Bjorn, 2016 p8 and Wang, 2014 p546). The number of antibiotics available for treating the condition is limited and works in the almost similar mechanism, this limits the fight against microbial and hence the need to invest non-clinical treatments that improve the activity against the illnesses caused by fungi, bacteria, and other pathogenic elements. This is the reason AP have been considered as an alternative treatment since various types have been found in at least each organism. This means that they can be manipulated and used to inform which peptide is effective in dealing with a particular health problem. For instance, bacteria produce the AP to eliminate other bacterial which competes in their niche. This activity can be monitored and establish the produced chemicals to design a treatment that counters the agent of infection. This can be based on the understanding the cell membrane of the bacteria which is paramount in the interaction between the microbial and targets for infection (Mahlapuu et al., 2016 p8 p10). This is why the AP act by disrupting the integrity of membrane of the bacteria. For instance, the lysozyme which is categorized as an AP works by digesting the bacteria leaving it to less harmful constituents (Bahar, and Ren, 2013 p1544). To get these disease-causing agents, their receptors are targeted on the surface of cells which triggers the immune system to respond by sending appropriate.

In conclusion, the AP is well-diversified molecules which naturally occur in a multicellular organism and during an immune reaction they are released as the first line of defense. The AP is dived into three categories of the antimicrobial peptide (AP) which include, the flexible AP, a-helica AP, and b-sheet AP. The first AP was discovered in 1922 by Fleming, but twenty years later he discovered penicillin as a very reliable antibiotic. This overshadowed the consideration of AP as a solution to microbial infections. However, the antibiotics started to fail, and scientists have shifted their focus to AP.



Bahar, A.A. and Ren, D., 2013. Antimicrobial peptides. Pharmaceuticals, 6(12), pp.1543-1575.

Cezard, C., Silva-Pires, V., Mullie, C. and Sonnet, P., 2011. Antibacterial peptides: a review. Science against Microbial Pathogens: Communicating Current Research and Technological Advances: Formatex Research Center.

Ebenhan, T., Gheysens, O., Kruger, H.G., Zeevaart, J.R. and Sathekge, M.M., 2014. Antimicrobial peptides: their role as infection-selective tracers for molecular imaging. BioMed research international, 2014.

Mahlapuu, M., Hakansson, J., Ringstad, L., and Bjorn, C., 2016. Antimicrobial peptides: an emerging category of therapeutic agents. Frontiers in cellular and infection microbiology, 6.

Pushpanathan, M., Gunasekaran, P. and Rajendhran, J., 2013. Antimicrobial peptides: versatile biological properties. International journal of peptides, 2013.

Phoenix, D.A., Dennison, S.R. and Harris, F., 2013. Antimicrobial peptides: their history, evolution, and functional promiscuity. Antimicrobial peptides, pp.1-37.

Sanchez, M.L., Martinez, M.M.B. and Maffia, P.C., 2013. Natural antimicrobial peptides: pleiotropic molecules in host defense.

Wang, G., 2014. Human antimicrobial peptides and...

Have the same topic and dont`t know what to write?
We can write a custom paper on any topic you need.

Request Removal

If you are the original author of this essay and no longer wish to have it published on the website, please click below to request its removal: