Quorum sensing may be defined as an occurrence where the buildup of signaling molecules permits a single cell to detect the number of bacteria in terms of cell density (What is quorum sensing? n.d.). The natural habitat contains numerous bacteria from different taxonomical groups, which possess and utilize distinct classes of signaling molecules. Current studies explore quorum-sensing systems in different microorganisms, for example, marine bacteria and disease-causing bacteria. This paper discusses the importance of quorum sensing in nutrient delivery, beneficial microbial relationships, virulence, and human diseases. The influence of quorum sensing on next-generation antibiotics and their mechanisms is also described.
Quorum Sensing and Nutrient Delivery to Bacteria
Quorum sensing leads to the production, sensing, and responding to signal molecules by bacteria. This process regulates social processes in bacteria. Bacteria normally create complex communities that relate closely to living and nonliving surfaces. These microbial communities are referred to as biofilms. Biofilms cling to surfaces, boundaries, or each other. Biofilm structures are usually formed to alleviate competition for nutrients and other growth factors. A typical biofilm structure comprises microcolonies covered in a hydrated medium of polysaccharides, nucleic acids, and proteins that are produced by the microbial cells. In such a setting, cells act as a joint living system as opposed to individual entities. Biofilms contain channels that convey water and nutrients to cells at the innermost section of the biofilm. The formation of biofilms is mediated by quorum sensing (Flemming et al., 2016). Hence, quorum sensing promotes nutrient delivery to bacteria through the formation of biofilms.
A Beneficial Microbial Relationship in the Human Body
An example of a beneficial microbial relationship in the human body is between microbes and the oral cavity. The mouth consists of different microbial habitats, including teeth, gums, tongue, lips, cheek, and soft palate. Microbes that inhabit the human oral cavity are referred to as oral microflora (Almståhl, Wikström, & Fagerberg-Mohlin, 2015). The oral microflora consists of more than 600 species, for example, species of Synergistetes, Bacteroidetes, Spirochaetes, Chloroflexi, Firmicutes, Actinobacteria, Chlamydiae, Fusobacteria, Proteobacteria, Streptococcus, Euryarchaeota, and Tenericutes. Oral microbiota may be suspended in saliva or attached to oral surfaces as plaque biofilm. Bacteria benefit from their host by using fluids in the oral cavity to sustain the homeostasis of the plaque biofilm. Additionally, saliva contains proteins and glycoproteins, which nourish the microbial populations. On the other hand, the oral cavity benefits from the association because oral microflora prevents pathogenic species from sticking to the mucosal surface and causing diseases.
Quorum Sensing in Virulence and Human Disease
A single bacterial cell is too small to have any significant impact on the host’s body. However, numerous bacteria manage to take down the immune system and cause disease by using quorum sensing. Once bacteria invade a human host, they continue growing and multiplying until they increase their numbers substantially. Quorum sensing helps the infectious pathogens to determine that they have attained a population that is large enough to mount a significant attack on the host. At this point, each bacterial cell exerts its virulence attack. Therefore, quorum sensing is used to regulate the pathogenicity of human disease (Bassler, 2009).
Next Generation of Antibiotics and Their Mechanisms
According to Dr. Bassler’s investigations on quorum sensing, the next-generation antibiotics may be chemical substances that target the disruption of quorum sensing in bacteria. Conventional antibiotics kill bacteria by destroying their cell membranes or interfering with replication. However, these new forms of antibiotics can block quorum sensing and prevent bacteria from communicating. As a result, it will be impossible to count and launch virulent attacks on their hosts. The antibiotics would be molecules resembling bacteria quorum sensing molecules. These molecules would bind bacterial receptors and prevent the recognition of the real signaling molecules.
Conclusion
Communication is a vital process in all living organisms. Quorum sensing allows bacteria to communicate with each other to perform specific activities, which may be beneficial or harmful. Investigations about promoting or preventing bacterial communications can help to enhance beneficial processes that arise from quorum sensing and destroy deleterious communications such as virulence in human diseases.
References
Almståhl, A., Wikström, M., & Fagerberg-Mohlin, B. (2015). Microflora in oral ecosystems and salivary secretion rates–a 3-year follow-up after the radiation therapy to the head and neck region. Archives of Oral Biology, 60(9), 1187-1195.
Bassler, B. (2009). How bacteria “talk”. Web.
Flemming, H. C., Wingender, J., Szewzyk, U., Steinberg, P., Rice, S. A., & Kjelleberg, S. (2016). Biofilms: An emergent form of bacterial life. Nature Reviews Microbiology, 14(9), 563-575.
What is quorum sensing? (n.d.). Web.