in this video, we're going to begin our lesson on simple staining. And so simple staining as its name implies, is going to be a relatively simple staining procedure that uses only one single die to stain the specimen. Now, there are two important things that you should remember regarding simple stains. We have numbered down below one and two. And so. The first important thing that you should remember about simple stains is that the inside of a bacterial cell is actually negatively charged with respect to the outside of the cell, which is going to be more positively charged. And so notice down below, we're showing you an image of a bacterial cell and we're specifically saying that the inside of the bacterial cell is negatively charged with respect to the outside. And so you can see all of these negative charges throughout the inside of the bacterial cell. To remind you that the inside of the bacterial cells negatively charged with respect to the outside, which is going to be more positively charged. So that's the first important thing to remember about these simple stains. Now, the second important thing to remember about the simple stains is that these simple dies can either be basic or acidic dyes and these guys are only going to be effective after they react. And so if we take a look at our image down below, notice on the left hand side, we're showing you a basic die. And on the right hand side we're showing you an acidic dye. Now, the basic diet is also sometimes referred to as a positively charged die and the acidic dye is sometimes referred to as a negatively charged. I now the reason for that has to do because these guys are named based on after their reaction. And so recall that basis will remove and lower the number of hydrogen ions in the environment by picking up hydrogen ions. And so notice that this basic dyes acting as a base and removing the hydrogen ion from the environment and picking it up and acquiring it. And so because this basic diet is picking up a hydrogen ion which is positively charged, the basic die is becoming more positive. And that's why basic dyes are known as positively charged dies. Now, acidic dyes, on the other hand, are going to act as acids and recall that acids will increase the number of hydrogen ions in the environment by releasing hydrogen ions to the environment. And so notice that arsenic die here is starting with the hydrogen ion. But after it reacts, notice that it releases the hydrogen ion to the environment, increasing the number of hydrogen ions and the environment and it is acting as an acid. But because it releases a positively charged hydrogen ion, the acidic dye itself is becoming more negatively charged, and that's why acidic dyes are known as negatively charged dies as well. And so this will be important to remember, especially when we move on to our next video and continue to talk more and more about simple dies. But for now, this year concludes our brief introduction to simple staining and how it only uses one single die to sing an assessment. And once again, we're going to learn more about the simple dies as we move forward. So I'll see you all in our next video.

in this video, we're going to continue our lesson on simple staining using basic and acidic dyes. And so recall from our last lesson video that really there are two main types of dyes that are used in simple staining that we have number down below one and two. And so the first type of dye used in simple staining is going to be the basic die. And the second type of dye used in simple staining is going to be the acidic dye. Now the basic die, as its name implies. And as we discussed in our last lesson video is going to act as a base to become a positively charged die particle that is going to stain the inside of cells. Now this is because the positively charged basic dive is going to be attracted to the negatively charged cell components that are found on the inside of bacterial cells. And so recall from our last lesson video that the inside of bacterial cells are going to be more negatively charged in the outside. And so these positively charged basic dyes are going to be attracted to the negatively charged cell components on the inside of the cell. And that's why they stain the inside of cells. Now the acidic dyes are practically the opposite of the basic dies because instead of acting as bases, they act as acids to become not positively charged but negatively charged basic dye particles. And because they are negatively charged instead of standing the inside of the cell, they are actually going to stay in the background of the cell the outside of the cell. And this is because the negatively charged acidic dyes are going to repel the negatively charged cell components and so they remain on the outside of the cell and color the background of the cell. And this is what we referred to as negative staining. A standing procedure that uses an acidic negatively charged I to stain the background of the cell instead of staining the inside of the cell itself. And so if we take a look at our image down below, we can get a better understanding of simple staining using basic and or aesthetic dies. Now simple standing only uses one di one single die. It will use either the basic die or it will use the acidic dye. Now recall from our last lesson video that the inside of bacterial cells are going to be more negatively charged with respect to the outside. Which is why we've got these negative charges here on the inside of the bacterial cell. And that's important to remember. And so over here on the left hand side, we're showing you the basic die which is also the positively charged dot. And so one way to remember that is that the lower case B. And basic kind of resembles the P. And the word positive. It's really just flipping the letter over. And so by noticing this resemblance, hopefully they can help you remember that basic dyes are the positively charged dies. And because they're positively charged they are attracted to the negatively charged inside of the bacterial cell. So they will directly stain the inside of the bacterial cell. And so sometimes basic positively charged eyes are also called direct stains or directs dies because they directly stay in the inside of the cells. And so over here we're showing you an image of a direct or a basic die being used to directly stain the inside of the cell. So notice that the inside of the cells is colored with that purple basic die. Now over here, on the right hand side, we're showing you the opposite the acidic dye. And so one way to help you remember that the acidic dye is the negatively charged I. Is that the A. In acidic is going to remind you of the A. In the word negative because positive does not have the letter A. And so the acidic dye is going to be the negatively charged I. And because it's negatively charges, is going to repel the negatively charged components on the inside of the cell, so it does not go to the inside of the cell. Instead, it remains on the outside of the cell and indirectly stains the sell by staining the background behind the cell. And so that's exactly what we see here. The background of cell is being stained, whereas the inside of the cell is not being stained. And so that's what we see over here in this image, that the cells themselves are the white circles, which the die is not inside those cells, but the die is found on the perimeter in the background of the cell. And so this is what we call acidic dyes, or indirect stains or indirect dies. Now these simple staining uh dies either the basic die or the acidic dye can really be useful for increasing the contrast of a bright field microscope and so therefore they can help to visualize the cells a lot easier. And so this here concludes our brief introduction to simple standing using the basic and acidic dyes and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.