Bacterial Quorum Sensing ( Qs )

“While motility is commonplace among the prokaryotes, it is important to note the variety of structures responsible for motility. These structures vary depending not only on the organism in question, but also on the particular environment” (Bardy, Ng, & Jarrell, 2003). “Study of the bacterial flagellum has provided insights into many aspects of prokaryotic cellular activities including genetics and regulation, physiology, environmental sensing, protein secretion and assembly of complex structures” (Bardy, Ng, & Jarrell, 2003). “Continued study of all prokaryotic motility structures will provide knowledge that is likely to reach far beyond the topic of motility and pathogenicity” (Bardy, Ng,

Prokaryotes are ubiquitous, successfully adapting to diverse environments as well as developing symbiotic relationships with host organisms (Lengeler, Drews, & Schlegel, 1999). Prokaryotes may have both autotrophic and heterotrophic characteristics. A cyanobacteria is photosynthetic, commonly called blue-green algae, and may produce toxins (Crayton, 1993). Bacteria are most commonly associated in the general

Bacteria will always want to thrive and do what is best for itself and find the most suitable host. The ideal situation between a host and bacteria would be mutualism which is a form of coevolution in which two species benefit from the same act. Michal Pollen briefly discusses this in Botany of Desires by comparing both bees and flowers. When he puts himself in the mind of the bee he can understand that the plants were luring the bees for there own desires. In other words, the plants get the bee to perform activities that they cannot themselves.

Symbiotic relationships are those that evolve between two organisms that interact in a specific manner with each other. These can range from being facultative, where the relationship is not required by either organism, to interactions that are obligate and are required by both organisms to facilitate survival. There are many mechanisms and processes that bacteria and their hosts can use to initiate and maintain symbiotic interactions and a few examples will be described in this report.

The purpose of the study by Barr et al. is to investigate an assumed symbiotic relationship between a bacteriophage and the mucus layer of a metazoan host, which may create a defense against microbes to protect the mucus layers from bacterial infection. The mucus layer has about four times more phage than bacteria, which is seen in preliminary testing, and because phage encode hypervariable proteins that may aid in adsorption to bacteria prey, the phages may work to protect the mucus layer be adhering to the surface with the hoc protein found in the capsid of the T4 bacteriophage. The study hopes to explain the importance of the co-evolution between phages and the mucus layer by presenting evidence of their symbiotic relationship, which

Biological agents, coming in a variety of forms, have unique abilities amongst themselves and all categories of environmental health agents. Bacteria holds the ability to

Vibrio fischeri is a Gram-negative bacterium that served as the model organism in this experiment. We isolated only the luxAB portion of the entire lux operon and inserted it into the pGEM vector plasmid to transcribe the luciferase enzyme required for bioluminescence. Within the lux operon, luxAB is responsible for producing subunits that form luciferase, which oxidizes the aldehyde made by luxCDE into the reduced flavin-mononucleotide FMNH2 and results in the production of light known as bioluminescence[6]. The luxI gene that is also present on the operon produces the “autoinducer which interacts with a regulator, LuxR, [and] activates transcription of the lux operon at high-cell density” to induce bioluminescence[4]. This interaction between the products of luxI and luxR is known as quorum sensing and serves as an evolutionary purpose in the symbiotic relationship with Euprymna scolopes, a type of squid that contains the light organ where the bacteria resides[6].

Both, Dr. Bassler and Dr. Dalino, explain how bacteria communicate and work together through quorum sensing. As Basler explained in her TED talk, bacterial cells make single producing proteins that attract other surrounding bacteria. They are able to receive these signals trough the signal receptor protein; this protein allows the bacteria to recognize when the cell density is high or low. If the cell density is high enough to perform the desired action, the group behavior turns on and they are able to work effectively as a way to reach their purpose. By working together, they are able to control pathogenicity and virulence; they continue to grow in their biofilms until they know they will be successful. Additionally, these single producing proteins are specific for intra-species communication meaning that the protein

My bacterium was swabbed off of a coke machine button. I decided to swab this particular spot because I believed there would be numerous bacteria found there since I see people everyday punching a button to get a cool beverage during breaks in between classes every day. To my surprise, there was only one colony that grew on the agar we had smeared it on. This was very surprising to me because I was sure there would be more bacteria growing on the machine rather than only one colony.

Quorum sensing isa form of cell-to-cell communication that bacteria use to coordinate the expression of genes involved in behaviours such as flagellar movement9,10 virulence factor production,11,12 and

This review provides background information on the relationship between bacteria and their phage, elucidating some of the mechanisms behind antagonistic coevolution and the resulting adaptations therein, and discusses the controversial use of phage therapy as treatment for some strains of antibiotic-resistant bacteria. Data extracted from a study utilizing a species of marine bacteria and phage is provided as an example of a few basic adaptations behind coevolution and how they can lead to diversification in both host and parasitoid defenses, and subsequently, their populations.

They coordinate certain behaviors based on the local density of the bacterial population. Many species of bacteria use Quorum Sensing to coordinate gene expression. Quorum Sensing is a bacterial cell to cell communication process that involves the production, detection, and response to extracellular signaling molecules called autoinducers. Autoinducers collect in the environment as the bacterial population density increases. Quorum Sensing is just a process bacteria use to talk to one another.

This regulate luminescence by diffusible molecule called autoinducer. The autoinducer comes from N-acylhomoserine actone (AHL), is has been proven that many gram negative bacteria make AHL molecular signals that comes in different lengths and substation in the third position of the acyl side chain. “Figure 7.20 representative cell-cell communication molecules. Pg. 165 7.5 Microbial Growth in Natural Environments.” Breaks it down how bacteria cell-cell communicaties and

Dr. Zemer Gitai received his bachelor’s degree from the MIT, and after this he completed his graduate endeavors from the UCSF. During this time, he concentrated in working on axon guidance in Caeorhabditis elegalns because he wanted to find out where the worm’s neurons came from and how they worked. This was the start of his interest in how small molecules such as proteins worked together as a complex system, and how spatial cues were being controlled. Dr. Gitai later joined Princeton University’s faculty and became the Director of Graduate Studies for the Department of Molecular Biology. Now Dr. Gitai focuses on the cell biology of bacteria and how their cells are able to self-organize across spatial scales.

*Please note that bacteria cells are very small and one "group"of bacteria is actually millions and millions of bacteria in just one small visable dot in a blacklight.