Biology Forums - Study Force

I'm writing a research proposal for undergraduate school. I'm wanting to test the effects of active ingredients of dental products against cultures of Streptococcus mutans. The active ingredients I'm currently thinking are sodium flouride, Triclosan, and Chlorhexidine.

What I am struggling with is developing an experimental design which will allow me to accomplish this. Any suggestions would be greatly appreciated! I also need a strategy to quantify data from these and compare them to each other and the control. It's further complicated because these act using both bactericidal and bacteriostatic methods.

Like I said, any ideas would be greatly appreciate. I swear I've read hundreds of articles and pages of literature of other research done and can't come up with a solid plan. Thanks!

(I've been looking at bioluminescence, don't know if this is really an option though at my school)

I'm familiar will all three test ingredients.

I don't understand why you can't simply culture the bacteria with each of the substances and see which ones grow the least amount of colonies? Do this three or four times for each (as repeats) and in the discussion section elaborate one why triclosan, for instance, inhibited growth the most. I.e. triclosan worked the best because it inhibits fatty acid synthesis by binding to the bacterial enoylacyl carrier protein reductase.

I can do this, and it's along the lines of how I want to. However, I need an assay to gather data. Whether that means bioluminescence or measuring the ring of growth inhibition is what I don't know. Any ideas?

I can definitely help you out ostste, but can you tell me what class this is for (i.e. microbiology)?

Here are some facts I came across:

Sucrose is the only sugar that S. mutans can use to form this sticky polysaccharide. Conversely, many other sugars—glucose, fructose, lactose—can be digested by S. mutans, but they produce lactic acid as an end product. So I'm guessing you're using a sugar based medium for growth.

I just can't see how you can use bioluminescence to test this. Bioluminescence works along the lines of how well an enzyme is working.

Lets work on this together and see what we can come up with.

The class is actually a research course in which we write a research proposal and then carry it out in a later class.

From what I've read about bioluminescence (and I could be way off track), but I was under the assumption that it could be used to measure the amount of ATP being produced by measuring the intensity of light, which would be a way to measure the amount of bacteria still producing ATP

You're right on the bio-luminescence (with the use of lucerfin, etc.) However, why would you care about ATP production when triclosan disrupts the biochemical prodcution of fatty acids? So, first you will grow the bacteria, inoculate it on a petri dish with a sugar based medium. Then you will see the growth of new colonies. My thoughts were, why not add each of these substances into the medium and see how the bacteria grow in conjunction with the toxicants.

Okay, you I found you some papers you may have missed. I suppose you can use their methods. If you come across some that cost money, we will download them for your free of charge since you are a member of Biology-forums.com

See attachments...

Websites: http://www.surechem.org/index.php?Action=document&docId=68909&db=USPTOA&tab=desc&lang=&db_query=0::0::0:&markupType=all (http://www.surechem.org/index.php?Action=document&docId=68909&db=USPTOA&tab=desc&lang=&db_query=0::0::0:&markupType=all)

Phan TN, Marquis RE. (2006) Triclosan inhibition of membrane enzymes and glycolysis of Streptococcus mutans in suspensions and biofilms. Can J Microbiol. 52: 977-983.

Tell me these are of any use to you.

Thanks for all of your work. I really can't express how much it's helped. I am slightly overwhelmed, and reading all of these articles makes me realize how much goes into these experiments.

I'm curious, what are your thoughts of growing the strep. mutans on an agar and then adding diffusion disks containing each substance and measuring the zone of inhibition?

thanks

I totally forgot about the disk diffusion test :-X... I think that is the only way to go at this point; this test is essentially used for your exact purpose.

Don't read too much into them, though. Start with the abstract and then move into the methodology (however, sometimes the methods are so technical they don't make sense :-\, but hang in there). Also make sure you have this equipment at the lab before doing your write-up!