Michelle's Turn
Michelle Ricchiuti will be presenting on Friday, February 26th. Her seminar title is: Identification of an ampicillin regulation gene in Stenotrophomonas maltophilia OR02. A link to some background reading can be found on the Seminar Schedule page.
Great job Michelle!
ReplyDeleteI find it interesting how the AmpG permease is responsible for beta-lactamase induction, which ultimately signals that there is damage being done to the cell and renders ampicillin to be non functional contributing to the S02 antibiotic resistance. The questions i have for the blog are: How conserved is the AmpG gene in the S02 strain? Since its already mutated once allowing for ampicillin resistance, if stressors (antibiotics) are introduced to the AmpG gene causing the beta-lactamase to be turned off resulting in no signals to the cell, will this permanently lead to the AmpG gene to be functionless resulting in maybe any type of antibiotic to work again? Any ideas?
AmpG activates beta-lactamase to signal damage of the cell wall. Classically, beta-lactamase will cleave beta-lactam antibiotics to render them inactive, leading to bacterial resistance to antibiotics. Although I cannot find how conserved the gene is within the So2 strain, I would imply that it is conserved. However, it is not difficult to test for or to reinsert an antibiotic resistance gene, considering this is an important marker for the research being conducted.
ReplyDeleteThe AmpG gene is conserved in the SO2 strain based on the fact that the resistance to ampicillin stayed constant while the strain was exposed to increasing concentrations of ampicillin. If another, non-mutated copy of this gene was present in the strain, ampicillin resistance might not be possible. The way I’m interpreting your second question is that an antibiotic is acting on the AmpG gene rendering the induction of the beta lactamases null. In my research I found that AmpG has an upstream homologue, AmpN. Together AmpG and AmpN form an operon that is essential for the expression of beta lactamases and when AmpN was mutated, beta lactamase activity decreased. If this were to hold true for AmpG, and beta lactamase activity was turned off, AmpG would be functionless. Therefore the strain would no longer be resistant to ampicillin and could now be treated with it?
ReplyDeletesince Beta lactam target the protein that involved cross-linking in the bacterial cell wall ,then the resistance of B-lactam in E.coli mediated by B-lactamase will hydrolyses the B-lactam ring and eventually inactivate the antibiotic.
ReplyDeleteBriefly looking through a little literature, it is suggested that the actual specific method of mutation can contribute to the efficiency of the antibiotic resistance. Different specific deletions, etc can affect the mechanisms by which antibiotic resistance is induced. Wondering if this is true for all areas of the AmpN and AmpG operon. Always interesting to hear about the research going on in other labs!
ReplyDeleteThe thing that struck me in regards to this presentation was not the genetic mechanisms themselves, but rather the incredible adaptability of the organism. Humans decide to dump heavy metals into this creek, and in only a few years entirely new strains of bacteria evolve to combat the harshness of the environment. Life is something of a paradox in that it requires extremely specific circumstances to arise in the first place, but shows amazing resiliency once established. Anyway, does anyone have any thoughts about the results of the Oscars? My two main gripes are that Mad Max should have won best visual effects and that Spotlight shouldn't have won best picture.
ReplyDeleteUpon reading the background information, I found it interesting that...S. maltophilia has been isolated from several sources, those including suction systems, tap water, I also believe they mentioned dental chair units. I am also glad to see that they did say they have reduced that by a point of use filtration system in most clinical settings because it has greatly reduced the amount of gram negative bacterial infections (at least in bone marrow transplants). Michelle did a great job, by the way! In response to the original question, I do believe the AmpG gene is conserved, although I am unsure of how conserved. I would definitely be interested to hear more about this after further studies have been done!
ReplyDeleteGoing off of what Marshall wrote, the adaptability of S. maltophilia is incredible. It has the ability to not just deal with a "normal" harsh environment such as pH, which is enough to kill most bacteria, but then to be able to take fairly high concentrations of heavy metals (concentrations that would kill even our cells) and is able to survive is awesome.
ReplyDeleteAlso, I agree about Mad Max, but haven't seen Spotlight so I can't comment on that.
Going off what Joseph said, It is crazy the climates and different areas in which different types of bacteria can live. From the coldest of climates like Antarctica to the blazing heats of a volcano. Talking about S. maltophilia its incredible the ability for it to survive with high concentrations of heavy metals. Metals like aluminum are extremely toxic to plants and can kill them off.
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