Messosomes: definition, function and composition

The mesosomes were called as such when they were detected by electronic microscopy. Initially they were Observed in 1953 by George B. Chapman, James Hiller and Rocío Wunderlichbut they were not yet called mesosomas, but peripheral organs were called. In 1959 they already obtained the name by which we know the mesosomes today.

There is controversy about whether mesosomes really exist or notIt was discovered that they appear only as damage to the plasma membrane in response to chemical fixing techniques to be observed with microscopy, so they do not exist in living cells. Messosomes were also discovered in prokaryotic cells that were exposed to antibiotics of chemical origin, in response to the damage exerted on them.

Today it is not yet established whether mesosomes exist as prokaryotic cells, or if they are an response to external effects, because there are still no conclusive results. There are scientists who do consider them as part of all prokaryotic cells, but others that completely discard it.

Now that we review this controversy, we present what is known about mesosomes, including what their definition and how they are.

The mesosomes are internal vesicular structures of prokaryotic cells, that is, of cells that do not have a true nucleus. They are presented as invaginations of the cell membrane inside the inner part, on the cytoplasm.

Being referral to this external membrane, its chemical composition is the same. In addition, they have Ovillus shape. On the other hand, it has been observed that:

• In gram positive bacteria: The mesosomes are great.
• In gram negative bacteria: They are smaller and not so frequent.

Do not miss this post about the types of bacteria that exist in Ecology Verde.

Messosomes are a plasma membrane derivation, so They have the same compositionthat is, the composition of the mesosomas is based on:

• A bipapa bipapo of proteins and lipids: The latter being more abundant and in a proportion 80:20. This layer is hydrophilic, which means that polar groups are in the outside while hydrophobic polar groups are located inside the bilayer.
• They have hydrophobic fatty acids: They are saturated or monounsaturated.
• They lack of sterols: Unlike the lipid membrane of eukaryotes.
• They have abundance of phospholipids: Derivatives of phosphatidic acid.
• They are relatively rigid: because of hipanoid polycyclic compounds.

Messosomes have particular functions and locations, and according to these locations we can have how mesosomes are classified:

• Side mesosomas: They are located on the sides of the plasma membrane. They have several functional enzymes.
• Septal or central mesosomas: They are found in the center of the cell and drag the membrane to this area, with a particular function that we explain below.

Messosomes are important prokaryotic cell components that help it complete all its internal and survival processes. Still You are not completely sure of what is the concrete function Of the mesosomes, but here we present those that have already detected.

Starting from the principle that mesosomes are only formed in response to damage, in that case their function is of protection and repair of the plasma membrane.

Now, if we consider that mesosomes are an essential part for all prokaryotic cells, we have the following functions:

• Increase the plasma membrane surface: so that it can carry out certain specific and specialized functions.
• They are responsible for transport enzymes: that produce the bacteria from inside out to interact with their surroundings.
• Side mesosomes serve to extend the cytoplasmic membrane: helping to increase the surface to complete their own functions, such as excretion. In these vesicular mesosomes there are many enzymes, so there are those who suggest that they work analogous to mitochondria, because they have respiratory enzymes. Recall that in prokaryotic cells the release of energy of breathing occurs in the cell membrane.
• In them it can occur oxidative phosphorylation: Metabolic process in which energy occurs in the form of ATP.
• The septal or central mesosomes push the membrane towards the center of the cell: With the intention that a necessary partition for cell division is formed, assisting in chromosomal separation and unfolding. Do not hesitate to discover more about chromosomes: what are, types and parts, then.

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