00:01
So this question is, devise a method to transfer micro -front soil to medium and also answer several questions.
00:08
So let's first of all talk about the procedure to transfer microbe to a medium.
00:26
So obviously microbes are mixed with soil, the dirt i would say.
00:32
So to transfer or isolate a microbe, you're going to have to use some liquid, in this case the saline solution so that to extract the microbe out and then we can use the saline solution that contain the microbe to dilute with a different medium to streak the plate.
00:51
So the very first step you want to collect the soil sample and you want to make sure all the the tools and container that you extract the sample are sterilized and so that you don't transfer microbe artificially into a sample again the tool that you collect must be free of other microbe.
01:23
So this is very important the tools and container must be sterile because we want to make sure the only source of microbe is from the soil.
01:36
The second step you want to weigh the portion of soil sample and so you want to make sure that you standardize the process and then you dilute the soil sample with some sterile saline solution and so that the microbe of inside of the soil sample is going to go into the saline solution.
02:06
Let me write down weigh.
02:08
You want to make sure the weighing part is very important because if you want to repeat this experiment you want to know the amount of soil that you use to extract a microbe.
02:50
Again this saline solution must be sterile.
03:09
So the microbes probably will be extracted and floating inside of the saline solution while the soil sample, the dirt itself, will settle down.
03:19
Then of course you centrifuge the sample and collect the supernatant.
03:41
As you can see, as we just mentioned, the dirt itself will actually sit down in the bottom so it will be discarded.
03:52
But the microbe will be floating in a supernatant which will be your stalk.
03:58
The next step, you obviously have your stalk but a lot of time you will have a lot of microbes.
04:05
Or you cannot really directly scrape them on the argot plate, then you will have them overgrow.
04:10
So it's very important for you to dilute them with medium so that you have different concentration.
04:17
So you will dilute the stalk that you get from number three with medium.
04:32
So now this time, the medium must be, again, sterilized.
04:36
So sterile medium to obtain different concentration.
04:45
And then you can do a serial dilution, let's say, to make sure there are tenfold difference.
04:59
And again, this is to prevent overgrowth of the microbe.
05:05
Then, once you have all the different concentrations ready, you can inoculate the microbe to an alga, which is also sterilized.
05:15
Again, you have different concentrations and it inoculates the samples onto agar dishes.
05:44
Again, you can use a very special sterilized technology, or we call it septic technology, to make sure when you inoculate the sample there is free of microbe from other sources...