Spheroplast

A type of bacterial cell with a partially removed cell wall

A spheroplast is a type of bacterial cell that has had its cell wall partially removed. This process typically occurs through the action of lysozyme or other enzymes that degrade the peptidoglycan layer of the cell wall. Spheroplasts are osmotically fragile and require an isotonic environment to maintain their structural integrity.

Formation

Spheroplasts are formed when the rigid cell wall of a bacterium is compromised, usually by enzymatic treatment. The peptidoglycan layer, which provides structural support and shape to the bacterial cell, is partially digested, leaving the cytoplasmic membrane intact. This results in a spherical shape, hence the name "spheroplast."

Enzymatic Treatment

The most common method for creating spheroplasts involves the use of lysozyme, an enzyme that specifically targets the glycosidic bonds in the peptidoglycan layer. In the presence of an isotonic solution, such as a solution containing sucrose or sodium chloride, the bacterial cell can survive without its complete cell wall.

Antibiotic Action

Certain antibiotics, such as penicillin, can also lead to the formation of spheroplasts by inhibiting the synthesis of peptidoglycan. This weakens the cell wall and can result in the formation of spheroplasts under specific conditions.

Applications

Spheroplasts are used in various biotechnological and research applications. They are particularly useful in studies involving the cytoplasmic membrane, as the removal of the cell wall allows for easier access to the membrane.

Genetic Studies

In genetic engineering, spheroplasts can be used to introduce DNA into bacterial cells. The absence of a rigid cell wall facilitates the uptake of foreign DNA, making spheroplasts a valuable tool in transformation experiments.

Membrane Studies

Spheroplasts are also employed in studies of membrane proteins and transport mechanisms. The removal of the cell wall allows researchers to study the plasma membrane in isolation, providing insights into its structure and function.

Limitations

While spheroplasts are useful in research, they are inherently unstable due to their lack of a complete cell wall. They are highly sensitive to changes in osmotic pressure and can easily lyse if not maintained in an isotonic environment.

Spheroplast gallery

• 
  Penicillin spheroplast generation
• 
  Patchclamp Spheroplast

Related pages

• Protoplast
• Cell wall
• Lysozyme
• Peptidoglycan
• Antibiotic