BACTERIAL SPORES: CHARACTERISTICS AND FORMATION - BIOLOGY - 2025

The bacterial spores are produced by bacteria capsules. In these capsules, the cytoplasm and genetic content of a cell are concentrated, which are wrapped in a series of protective layers.

These are highly resistant to unfavorable external conditions, such as high and low temperatures, droughts, radiation, among others. They are also resistant to chemicals created by humans, such as antibiotics and disinfectants.

Bacillus anthracis spores, which causes the disease anthrax.

In addition to this, the spores can remain in an inactive state for many years, decades, or even longer. Once the spores detect improvements in environmental conditions, they will break down, releasing their content.

For this reason, they play an important role in the survival of the bacteria, since the fact that the spores can survive in such conditions makes it almost impossible to eliminate them.

The spore-producing bacteria usually belong to the genera sporolactobacillus, clostridium, and bacillus. These bacteria are usually found in the soil.

characteristics

- Spores can remain inactive for long periods of time.

- These structures are resistant to heat, pressure, radiation and strong acids and bases. In general, they are able to withstand extreme conditions that very few organisms can cope with.

- The spores are in a state of semi-dehydration. Only 10% of the water from the stem cell is passed to the spore during its formation.

- Due to this dehydration, the spores can develop resistance to extreme temperatures and certain chemical substances.

- Spores contain some proteins that have two main functions. The first is to protect the deoxyribonucleic acid (DNA) from radiation, heat, and other similar conditions. The second is to provide energy that can be of use to the spore.

- When the spore detects favorable changes in environmental conditions, it leaves its latent state. It takes the energy provided by proteins and grows a cell. This process is known as germination.

Formation of bacterial spores

Environmental conditions are not always stable. For this reason, bacterial cells must resort to certain mechanisms.

When a bacterium feels changes in environmental conditions, it has two options: adaptation or differentiation. If you decide to adapt, the bacteria will continue to live in the environment. In other words, it will continue to grow and cope with the conditions (running the risk of dying in the process).

If you opt for differentiation, structures will be created that will aim to ensure the reproduction, survival or even dispersal of organisms. An example of this is the creation of capsules called spores.

The spores can remain dormant until external conditions improve. In case the bacteria decide to sporulate, it must go through a series of stages, which are presented below:

Stage 0

The cell is in the growth stage.

Stage 1

There is an exchange of proteins within the cell, so that the DNA begins to become more abundant.

Stage 2

DNA is divided into two parts. One will remain within the stem cell while the other will be destined for the spore. Each of these portions will be located at different poles of the cell.

At this stage the cytoplasmic membrane begins to produce a barrier, separating the stem cell from the spore.

Stage 3

The cytoplasmic membrane closes completely around the spore.

Stage 4

A protective layer is formed, called the cortical cortex. This layer is made up of proteins. At this stage, the exospore is also constituted, which is the outermost layer of the spore.

This is one of the most important phases, since it is thanks to these layers that the spores acquire resistance to the various external conditions that could affect them.

Stage 5

The cytoplasm is compacted and the elements are organized within the spore, with which it matures.

Stage 6

The spore is released outside.

Spores life time

Studies on the longevity of spores indicate that spores can remain inactive for a decade, or even many more years.

The life span will vary according to the species of bacteria and the specific conditions that the spore must endure.

For example, a study that was carried out with the bacterium clostridium aceticum showed that, even after three decades, the spores of this microorganism were still alive.

Also, spores have been found that date back to much older times. In 1995, Cano and Birocki conducted a study with bacterial spores preserved in amber crystals.

The date of origin of these organisms was between 25 and 40 million years. Despite this, the scientists were able to "resurrect" them.

Another study found spores of halophilic bacteria preserved in salt crystals. These bacteria dated back 250 million years. In summary, bacterial spores can survive for many years if they are kept in the right medium.

Bacterial genera and spores

The bacteria that usually form spores are those belonging to the genera bacillus, clostridium and sporolactobacillus.

The genus bacillus forms oval-shaped spores and is one of the most resistant. An example of this is bacillus anthracis, responsible for the deadly disease anthrax.

For their part, the spores of the genus clostridium differ from other bacteria because their shape is elongated (as if it were a bottle) and not oval. An example of the bacteria of this genus is clostridium tetani, which causes tetanus.

Lastly, the genus sporalactobacillus produces spores with a rounded shape.

Bacterial spores and

Microbiology is the branch of biology that is responsible for the study of microscopic organisms, such as bacteria.

This science analyzes the evolution and properties of microorganisms, detecting their function, their influence on terrestrial life and their usefulness.

The study of spores has been of importance for microbiology. Knowledge of these structures has allowed progress to be made in the area of ​​sterilization, especially in medicine, agriculture and the food industry.

References

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8. Types of Spore Forming Bacteria. Retrieved on September 28, 2017, from sciencing.com