Chapter 14

Episode 14: The Discovery of Bacteria (4)

The lecture… it wasn’t over yet.

Istina and the other undergrads were staring at me. Some looked more tired than before, while a few still burned with curiosity and academic fervor.

“Look closely now. Organ systems are made up of organs, which in turn are composed of tissues… so what makes up tissues?”

Istina blinked blankly again. Organs, organ systems, tissues… so what?

“Istina, didn’t you graduate? Why don’t you know this? Oliver, answer this.”

This is one of the basic principles of biology…

Structure and function are closely related.

Biological units must be structures that separate internal from external environments while maintaining life functions.

“Uh… I’m not sure.”

“Think logically. Life processes involve separating inside from outside and controlling it. Therefore, the basic unit of life must have a similar structure—like small rooms.”

That’s cells.

I returned to the human diagram I’d drawn earlier. Organism, organ system, organ, tissue… leading to the final step: the smallest unit of life activity.

– Cells.

Most students still wore expressions of confusion, but the cell theory isn’t just proven by observation—it’s fact and logical conclusion.

“That’s all for today. If there are no questions, class is dismissed. See you next week.”

The lecture ended there. No one asked questions, though some students had questioning looks. Going overtime is inconvenient for everyone, especially since I’m exhausted from explaining so much my mouth hurts.

I may have wrapped things up faster because I got tired mid-explanation, but I said everything I needed to say.

As soon as class ended, Istina approached me with a stack of papers, writing something down.

“I finally understand what you said last time! Though… we still need proof, right? But we’ve got microscopes, so it’ll be quick!”

Right.

Our upcoming experiments will be simple. Now that we’ve figured out how to make culture media, we can grow bacteria, stain bacterial colonies, and observe them under the microscope—all likely within today or tomorrow.

“Are we experimenting today?”

“Yeah, I’ll show you how to use petri dishes.”

In modern times, custom nutrient solutions existed for every type of bacteria, but here we’re improvising with soy-based culture media. It’s disappointing, but whatever grows should include common bacteria like Staphylococcus aureus or Streptococcus.

*In the lab*

Istina and I carefully poured the culture medium from a flask into petri dishes. A thin layer of bean paste settled on the bottom like green tofu film.

“This should be enough, right?”

The medium solidified instantly on the dish surface.

I nodded, and Istina closed the lid. After several steps, nine petri dishes were prepared.

“What happens next?”

We need to inoculate bacteria onto the dishes using sterilized tools.

This method allows us to form visible colonies that can be counted or moved for further study.

I lit an alcohol lamp and sterilized the needle tip. Let’s wait for the dishes and needle to cool.

Today’s sample is plain water touched by a hand.

The needle traced lines across the dish.

“When inoculating, try not to overlap paths; overlapping might cause bacterial colonies to merge.”

“Ah.”

“The goal is to get bacteria to form colonies on the dish. Whether it works perfectly or not, something should grow.”

Bacteria are everywhere. If bacteria don’t grow, fungi surely will. Istina scratched her head.

“Bacteria are too small to see with the naked eye, so what difference does growing them make?”

“In controlled conditions, bacteria form colonies—millimeter-sized lumps that can be seen and manipulated.”

“How do you know all this, Professor?”

“Because I’ve done it before.”

I handed the needle to Istina.

“Your turn.”

Istina stared intently at the dish while I checked the clock—4 PM. How long does it take for bacteria to grow?

Staphylococcus aureus forms colonies in about 12 hours. Though it’s 4 AM now, academic pursuits know no day or night.

I shook Istina awake from her nap in the library.

“Istina, wake up.”

“Please… I’m sorry…”

She talks in her sleep.

“We need to check the bacteria.”

“I don’t want to…”

You chose grad school, Istina. Tough it out.

Istina rubbed her messy hair, blinked her eyes, and slowly stood up, finally realizing the situation.

“Sorry, please forget that.”

“Sure.”

Istina avoided my gaze.

“Did the bacteria grow?”

“It’s been long enough.”

“Let’s check… but Professor, couldn’t we have waited until sunrise?”

*At the research lab*

The cultures were successful… sort of. Barely ten colonies grew per dish. What went wrong? Regardless, Istina was amazed.

“Just like you said, Professor! From the bacteria growth to colony size… we just need to move the colonies under the microscope now.”

I nodded.

“Now we just need to look through the microscope.”

“Out of curiosity, do colonies keep growing if left alone?”

No, they don’t.

Colonies lack internal transport systems for nutrients and oxygen, limiting their size.

“Once they reach critical size, they can’t grow further due to nutrient diffusion issues.”

Istina jotted something in her notebook.

“I’ll get the slide.”

I carefully picked up a colony with forceps and placed it on the slide. Next, we need to fix the sample.

I dropped a distilled water droplet on the colony, then dried it over the alcohol lamp.

The sample prep is almost done. All that’s left is staining. Istina added the prepared stain to the sample.

Ah, that’s right.

Staphylococcus aureus grows best around human body temperature—36.5°C. Culturing at room temperature probably limited results, but one colony should suffice.

Let’s wait a bit.

“I’m sleepy.”

“You can nap later this afternoon.”

“What do bacteria look like?”

“Pretty boring. Usually round or rod-shaped. Occasionally weird ones exist.”

Like Treponema pallidum, which has a strange spiral shape, but our equipment can’t detect such details. Our microscope barely meets the minimum requirements for seeing bacteria.

Let’s check.

I moved the sample under the microscope, adjusted the focus… and yes, they’re clearly visible. Clusters of purple granules.

Definitely Staphylococcus aureus.

Now I understand why it’s called “grape-like” cocci—they cluster like grapes and stain purple with Gram staining.

“Istina, come look.”

Istina peered into the microscope.

“I can really see them… these are bacteria, right?”

“Yep.”

Istina sat back down, wearing an expression like a child who just received a birthday present.

“This will open new horizons for humanity. It might be the greatest discovery of this century!”

I understand her excitement, but it’s too early to celebrate.

This is merely the beginning. Antonie van Leeuwenhoek discovered microscopes, Hans Christian Gram discovered staining methods.

We still need Joseph Lister to connect hygiene with clinical practice, and Pasteur to prove bacteria cause disease.

“Let’s document the results. We need to write the paper and publish quickly.”

Istina nodded.

Right, I meant to visit Professor Klaus after class but never got around to it. Maybe having tangible results will make the conversation smoother?

I’ll summarize the experiment first and go from there.

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