Mycoplasma

Mycoplasma is a type of bacte ria, and it doesn’t have a cell wall. Because of this, some antibiotics do not work on them. Mycoplasmas are known to be the smallest living organisms on earth. They are among the simplest living things that can reproduce by themselves.

Mycoplasmas can live without oxygen. They can take many shapes. Some look like a flask. Others look longer or round. They can live as parasites or feed on dead material.

History and Naming

The name “mycoplasma” was first used in 1889. The word comes from Greek. “Mykes” means fungus, and “Plasma” means formed. Albert Bernhard Frank coined the name Mycoplasma.

Scientists thought these microbes had both cell and non-cell stages. They could pass through filters that stop other bacteria. Mycoplasma were once called pleuropneumonia-like organisms, or PPLO. This name was given because they looked like bacteria that cause pneumonia in cows.

Structure and Shape

Mycoplasmas have no cell wall. Their outer layer is a cell membrane. This makes them flexible, and they can change their shape easily.
They are very small, about 0.2 to 0.3 microns in size. This makes them some of the smallest bacteria.
The cell contains a minimum number of organelles.
It has a genome that consists of a double-stranded circular DNA molecule, which is naked, and ribosomes that are of the 70S type.
When grown in a lab, their colonies look like tiny fried eggs.

Alt text: Structure of mycoplasma

Species and Hosts

There are over 100 species of Mycoplasma. Most can cause disease. Some species infect humans.

Mycoplasma pneumoniae causes walking pneumonia, a mild infection that affects the lungs.
Mycoplasma genitalium can cause pelvic disease that harms the reproductive organs.
Many species infect animals like cows, chickens, and others. They can cause lung, joint, and other infections. They damage tissues by releasing toxins.

Treatment and Prevention

Doctors treat mycoplasma infections with antibiotics like tetracycline. Penicillin doesn’t work as these bacteria have no protective cell wall.

Growth and Nutrition

Mycoplasmas require cholesterol to keep their membranes strong. This is rare for bacteria. Their DNA is very small, with only 500 to 1,000 genes. They cannot make many nutrients on their own. So, they depend on their hosts for food. They can live with or without oxygen. They are the simplest self-replicating bacteria. Mycoplasmas reproduce through binary fission, but sometimes the division of the cytoplasm lags behind genome replication, leading to the formation of multinucleate filaments.

How Do We Find Mycoplasma?

Mycoplasmas are hard to find in the lab. They grow slowly and are very small. Usual antibiotics like penicillin cannot kill them.

Doctors use blood tests and special DNA tests like PCR. On lab plates, colonies look like small fried eggs.

Evolution and Study

Mycoplasmas came from bigger bacteria long ago. They lost many genes over time. Scientists study them to learn about the smallest life forms. Mycoplasmas help in research on building simple synthetic cells.

Summary

Mycoplasma are tiny bacteria without a cell wall. Some antibiotics, like penicillin, don’t work on them. They can change shape easily and live without oxygen.

Mycoplasma infects humans and animals, causing diseases such as pneumonia. They need hosts for nutrients and can hide from the immune system. Detecting them is difficult. Treatment uses special antibiotics. Scientists study them to understand simple life forms and improve medicine.