HELLLP

[Daven Makwana_]

This is regarding procedures for Yeast Busters:
I was told to dilute a high concentration further to make a low concentration . How do I do so.

[Daven Makwana_]

This is regarding procedures for Yeast Busters:
To make a low concentration , do you only have to add the water, sugar, and yeast combination to step 9b.
If this is not correct, please follow up with the correct steps on how to make both a low and high concentration. I did not quite understand the procedures provided.
I did my tests and was wondering if anyone could post results with there own experience to make sure my results was correct

[donnahardy2]

Hi Daven,

I think you are doing this really great project from the Science Buddies website:

http://www.sciencebuddies.org/science-f ... #procedure

You have a very good question. Step 9b describes the dilution of your antifungal. The first step, adding 1/8 tsp antifungal to 9/8 tsp water is a 1:10 dilution. The next step, taking 1/8 tsp of the 1:10 dilution in 1/4 cup of warm water with sugar is a 1:100 dilution, so the final dilution is 1:1000 for the high concentration sample or 10 ug/mL

The procedure then suggests diluting the 1:1000 dilution by adding 1/8 tsp of the 1:1000 dilution to 1/14 cup of water with sugar. So the low concentration sample is 1:1000 x 1:100, or 1:100,000, or 0.1 ug/mL.

This is an example of of a dilution for a 1% antifungal. The procedure suggests checking the literature to find out what the effective concentration of the antifungal you will be working with. What antifungal agents are you testing?

If you followed this procedure and measured the amount of carbon dioxide produced, then your results are correct. When you do a science experiments until controlled conditions, your results are never incorrect.

However, if you obtained results that don't seem to make sense, please let us know what antifungal you used, what you did, and what your results were. Did you run a control with no antifungal? Did you repeat your results?

Please post again and explain why you are concerned about your results.

Donna Hardy

[Daven Makwana_]

Thanks for the reply,
Did you mean to make a low concentration you had to add 1/8 tsp of the 1:1000 dilution to 1/4 cup of water and sugar, not 1/14. If it is 1/14, where did you receive that number.

I kept getting confused with the procedures because there are many of them, would you be able to type up a step by step procedure of yeast busters. Thanks if you can.

[Daven Makwana_]

My low concentration never worked for micatin, clotrimazole, or tinactin. Is there a reason. I followed your steps, using 1/4 and 1/14 of water. None seemed to replace any water.

[Daven Makwana_]

My low concentration never worked for micatin, clotrimazole, or tinactin. Is there a reason. None seemed to move the water.

[donnahardy2]

Hi Daven,

Sorry, the 1/14 is a typo. The 1:1000 dilution is one-eighth teaspoon of the 1:10 dilution of the antifungal in one quarter cup water.

It sounds like you observed no gas production in the low dilution of all of the antifungals. Lack of gas production indicates that the yeast were inhibited and were not metabolizing the sugar, and this is a possibility.

Can you confirm that you made the low dilutions in sugar water and that these samples also contained yeast?
Was there gas production in the control sample with no antifungal added?
Was there gas production in the 1:1000 dilution sample?

Was your first dilution of the antifungal 1/8 tsp antifungal plus 9/8 tsp water?
Was your second dilution (high concentration) 1/8 tsp of the first dilution plus 1/4 water with sugar and yeast?
Was your third dilution (low concentration) 1/8 tsp of the second dilution plus 1/4 water with sugar and yeast added?

Was the temperature the same for every trial?
Did you add the same amount of yeast and sugar to every sample?


Please answer the questions as this may help me understand what is happening in your experiment. I've looked at the procedure again and it is fairly detailed, so I'm not sure what's wrong.

Do you have access to a balance and containers that will allow you to measure using metric measurements? For example, weigh 1 gram of antifungal and all 10 milliliters of water? This would help you understand the dilutions better.


Donna Hardy

[donnahardy2]

Hi Daven,

I just answered this question in your original topic. It's better to always post a reply in the same topic so the experts following your topic will be notified.

Donna Hardy

[Daven Makwana_]

Was there gas production in the 1:1000 dilution sample? Yes

Was your first dilution of the antifungal 1/8 tsp antifungal plus 9/8 tsp water? No because it said that was for high concentration( wasn't 1/8 antifungal plus 9/8 water and also sugar a high concentration then 1/8 of this is low)
Was your second dilution (high concentration) 1/8 tsp of the first dilution plus 1/4 water with sugar and yeast? No this was my first
Was your third dilution (low concentration) 1/8 tsp of the second dilution plus 1/4 water with sugar and yeast added? No this was my second ( wasn't 1/8 of high concentration plus 1/4 water with sugar and no extra yeast added)

Was the temperature the same for every trial? Yes 110 deg f
Did you add the same amount of yeast and sugar to every sample?
Yes

.
.

[donnahardy2]

Hi Daven,

Thanks for answering the questions.

The directions include an initial 1:10 dilution of the antifungal in water, so you started with a 1:100 dilution. Your second dilution was a 1:100 x 1:100, or a 1:100,000 dilution. This is fine; for your project board, you just need to report what you actually did.

You observed gas in the 1:100 dilution, so the yeast were metabolizing in the more concentrated dilution. I would expect that you would observe more gas production in the 1:100,000 dilution as the antifungal was less concentrated in this sample. Is this what happened?

You did a good job of keeping all other parameters controlled, temperature, and the quantity of yeast and sugar, so the only difference in the samples was the concentration of antifungal so you should be able to quantitatively compare the amount of gas in each sample.

Since you did not answer the question about the gas production in the control sample, I am guessing that you did not test a sample with just yeast and sugar (no antifungal). If this is the case, I recommend that you set up this control so you can compare gas production of the antifungals with the control sample. Your project is due soon, and you should be concentrating on writing up your project board, but the negative control sample is essential for your experiment.

Please post the quantity of gas production in each concentration of the antifungals you used? I am very interested in seeing your data.

I hope this helps. Did all of my comments make sense? If not, let me know if you have questions.


Donna Hardy

[Daven Makwana_]

To be honest I'm not quite sure of all the 1:100 numbers, but is what I did so far okay. I thought the whole point of this experiment was to reduce gas production which displaces water. So in a low concentration, more gas is produced
My results are as follows in average cm displaced

Tinactin
High concentration 1cm
Low concentration 0 cm

Clotrimazole
High concentration 2cm
Low concentration 0cm

Micatin
High concentration 3 cm
Low concentration 0 cm

Would you be able to average out some results as I really believe these tests were not accurate.
My project is actually due at the end of the month because of extension.

I know clotrimazole is an all allilamine and tinacin an azole, so is one supposed to displace more than the other.
I also made a control with only yeast.

[donnahardy2]

Hi Daven,

You are correct about the objective for this experiment; if the yeast are inhibited by the antifungal, they will produce less gas. So you results are interesting; if you obtained 1 to 3 cm of gas with the high concentration, then I normally expect more gas production with a lower concentration of antifungal.

I’m not sure what happened with your experiment, but normally, results like this can be explained by repeating the experiment and including a control. Since you do have a little time, I would recommend repeating your results with one of the antifungals and include a control with yeast and sugar that does not contain any antifungal. The control will be your baseline for gas production and you will be able to quantitatively compare results to the samples with different concentrations of the antifungal.

Depending on the results, you can then decide to repeat the results with the other antifungals. Let me know what happens.

Donna Hardy

[Daven Makwana_]

Low concentration would be around how many centimetres for gas production.

[donnahardy2]

Hi Daven,

The quantities of gas are relative and you won’t know how many centimeters will be produced until you do the experiment. The amount of gas produced depends on the number of yeast cells, the temperature, time and oxygen availability, but you have to do the experiment to get the answer.

It would be helpful to know what volume of gas is being produced. What is the diameter of your collection container? Can you calculate the volume based on the centimeters of gas produced?

You will be measuring centimeters (or volume) of gas for the control and for each dilution of the antifungal. You will be able to calculate the percentage of gas produced in each sample compared to the control.

How are you going to present your results? What kind of a graph are you planning to use?

Donna Hardy

[Daven Makwana_]

Would you suggest a particular graph to use. How would I calculate the volume of yeast. When I present my data, should I use a line graph to show the water displaced over the 30 min per test. Should I do it in cm or is there a particular unit