episode_0014

Episode 14. The Discovery of Germs (4)

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Class isn’t over yet.

Istina and the other undergraduates were looking at me. Some of them looked a little more tired than before, while others seemed curious or eager to learn.

“Look. The organ system is made up of organs, and organs are made up of tissues. Then what are the units made up of the tissues? ”

Istina blinked her eyes again. Organ system, organ, tissue… … . What should I do?

“Istina. You graduated from college, so why don’t you know anything? Oliver. Answer me.”

Biology, and one of its fundamental principles.

Structure and function are closely related.

The reason why the basic unit of a living organism is a cell is because the basic unit must also be a structure that maintains life activities while being separated from the outside.

“Uh… … . I don’t know.”

“Think logically. Life activities are ultimately about separating the inside from the outside and controlling it. The basic unit of a living organism must also have a similar structure. A small room structure.”

That’s a cell.

I went back to the drawing of the person I had drawn earlier. Individual, organ system, organ, tissue. The last stage is the smallest unit of life activity.

– Cells.

Most people had expressions of not understanding. The cell theory was not proven by observation alone. It is also a fact, and if you think about it carefully, it is a logical conclusion.

****

“That’s it. If there are no questions, class ends here. See you next week.”

The class ended like that.

There were no questions. Some students had questions on their faces, but it was difficult for everyone to go over class time. I was tired. My mouth hurts from explaining too much.

As I was talking, I got tired and it felt like it ended a bit too quickly, but I said everything I wanted to say.

As soon as class ended, Istina walked toward me, holding a stack of papers. She seemed to be writing something, but I don’t know what.

“What you were saying last time. I now understand what you meant! Well… … . I still have to prove it. But since I have a microscope, it will be done soon. ”

right.

Anyway, the experiments that will be conducted for the time being are simple.

I also found a way to make culture media, so I made culture media, grew bacteria, stained the bacterial colonies, and observed them under a microscope. I think I can finish this today or tomorrow.

“Are you doing the experiment today too?”

“Okay. I’ll show you how to use a petri dish.”

“Aha.”

In modern times, there were ready-made nutrient solutions tailored to the type of bacteria you wanted to grow. It’s a bit unfortunate that that’s no longer possible.

What would grow in a culture medium made of soybeans? Probably very common bacteria, such as Staphylococcus aureus or Streptococcus. The type of bacteria is not particularly important right now.

****

laboratory.

I slowly poured the culture solution from the pitcher with Istina. The starch-mixed soybean powder filled the bottom of the petri dish like a film.

“Is this enough?”

The culture medium solidified right on the petri dish, like a very thin jelly.

I nodded, and Istina covered the petri dishes. It took some time, but nine petri dishes were ready.

“What happens now?”

You need to inoculate the bacteria into a culture dish.

The method is simple.

A solution containing bacteria is applied to a culture dish using a sterilized tool. The microorganisms that settle on the culture dish form a colony.

A colony is a visible object. A particular colony can be physically separated or moved for further study. The number of colonies grown on a culture dish can also be counted.

The above method can also be used to indirectly evaluate the amount of bacteria in a specific solution.

Anyway, I lit an alcohol lamp and sterilized the needle head with fire. Let’s wait a little while for the culture dish and needle to cool down.

The solution that will be studied today is plain water that you just dip your hand in and then take it out.

The needle moved across the culture dish.

“Inoculate the culture dish in a dense manner with the needle lines not overlapping. If the lines overlap, the bacterial colonies may overlap each other.”

“Aha.”

“The goal is to get the bacteria to form colonies on the petri dish. I don’t know if it will work, but maybe something will grow.”

In fact, there are so many bacteria around. If bacteria don’t grow, fungi will. Istina scratched her head.

“Bacteria are so small that you can’t see them. What difference does growing them make?”

“When grown in a controlled environment, bacteria form colonies. Colonies are clumps of bacteria, a few millimeters in size. Colonies are visible and can be manipulated.”

Once bacteria have formed colonies on a petri dish, they can be stained, placed under a microscope, or cultured for study.

“How do you know that, Professor?”

“Well, I’ve done it before.”

I gave the needle to Istina.

“You try it too.”

Istina looked at the petri dish, and I checked my watch. It was 4:00 PM. How long does it take for bacteria to grow?

****

It takes about 12 hours for a colony of Staphylococcus aureus to grow. It is 4 a.m. now, but there is no day or night in science.

I woke up Istina, who was sleeping in the library. She seemed to have collapsed while studying.

“Istina. Wake up.”

“Please, save me… … . I was wrong… … .”

Talking in your sleep.

“I have to go grow some bacteria.”

“I don’t like that kind of thing… … .”

You are the graduate student of your choice. Fight with evil and courage, Istina.

Istina fiddled with her hair, rubbed her eyes, and slowly got up from her seat. Only then did Istina seem to have come to some sense of the situation.

“I’m sorry. Please pretend I didn’t hear that.”

“Yeah.”

Istina avoided my gaze.

“Bacteria, are they fully grown?”

“It’s time to grow up.”

“Let’s go see… … . But, Professor. Can’t we check it after the sun rises?”

****

We arrived at the lab.

The cultivation was a success. There were hardly any colonies that grew successfully. It seemed that less than ten grew on a plate. What could be the reason? Whatever the reason, Istina was impressed.

“It really worked out just like the professor said. From the growth of the bacteria to the size of the colony. All I had to do was move the colony under the microscope.”

I nodded.

“Now all you have to do is look at it through a microscope.”

“I’m just curious. If you leave a bacterial colony alone, will it continue to grow?”

That’s not it.

Bacterial colonies do not have a system to transport nutrients or oxygen to the interior. Therefore, bacterial colonies cannot exceed a certain size.

“Once it reaches a critical size, it becomes difficult to grow any larger. Because nutrients cannot reach the center of the colony.”

Istina wrote something in her notebook.

“I’ll bring the glass plate.”

I carefully picked up one colony with tweezers and placed it on the glass plate. That was it, I had to figure out how to fix the bacteria.

I dropped a drop of distilled water on the colony placed on a glass plate and dried the sample by passing it over an alcohol lamp.

The sample preparation was almost done, and now all that was left was to dye it. Istina dropped the dye she had brought onto the sample.

Oh, I remembered.

Staphylococcus aureus grows best at human body temperature, around 36.5 degrees Celsius. Since we tried culturing it at room temperature, the results were bound to be somewhat lacking.

Well, one colony is enough.

Now we have to wait a bit.

“I’m sleepy.”

“Get some sleep later in the day.”

“What do bacteria look like?”

“They look boring. Usually spherical or rod-shaped. Sometimes there are some weird ones.”

For example, the syphilis bacteria have a strange spiral shape, but we don’t have the technology to see that. The microscopes we use now are close to the minimum specifications for seeing bacteria.

Let’s take a look.

I moved the sample under the microscope. Focused, and uh… I was a little worried, but it looks fine. There are round purple grains gathered together.

Even at a glance, it is Staphylococcus aureus.

I think I know why they’re called staphylococci. They grow in clumps like grapes, and when you do a Gram stain, they usually turn purple.

I took my eyes off the microscope eyepiece.

“Istina. Come here and see.”

Istina looked into the microscope.

“I can really see it… … . Is this bacteria?”

“Yeah.”

Istina sat back down, looking like a little child who had just received a birthday present.

“It will be a new horizon for mankind. It may be the greatest discovery of this century.”

It’s not that I don’t understand your feelings, but it’s still too early to be happy.

This is literally just the beginning. Hook discovered the microscope, Gram discovered dye.

There are still experiments left by Lister, who discovered the need for hygiene in clinical settings, and Pasteur, who discovered that bacteria were the cause of disease.

“Let’s write the research results. We need to write the paper quickly so that we can publish it quickly.”

Istina nodded.

That’s right, I was going to go see Professor Klaus, but I couldn’t go because class ended earlier.

But wouldn’t the conversation be easier if there were visible results?

First, let’s organize the experimental content.