What is Sphaeroplast?

A Spheroplast (or sphaeroplast according to British use) can be described as a microbe organism with a cell wall that is almost entirely gone through the penicillin or Lysozyme. According to certain definitions the term is employed to refer to Gram-negative bacteria. In other definitions, the word also includes yeasts. Spheroplast’s name is derived in the sense that once the cell wall of the microbe is digested by membrane tension, the cell to take on the characteristic shape of a spherical. Spheroplasts can be osmotically fragile and can lyse when transferred to a hypotonic environment.

In the context of Gram-negative bacteria”spheroplast” refers to cells in which the peptidoglycan part but not the membrane that forms the cell wall has been removed.

Origin of Sphaeroplasts

The term “spheroplast” originates from the circular shape that is adopted by bacterium following the destruction of the cell wall. This shape is beneficial to its survival in extreme conditions. Despite this structural change, the cells are extremely vulnerable to stress in the environment like osmotic or mechanical shock. For instance the peptidoglycan membrane in bacteria is designed to react to different Ionic levels inside and outside of the cell. The loss of this layer results in the loss of this protection as well as the sensitivity to stress caused by osmotic.

Spheroplasts Formation

There are two methods by which Spheroplasts are formed such as;

1. Antibiotic-induced spheroplasts
2. Enzyme-induced spheroplasts

1. Antibiotic-induced spheroplasts

Many antibiotics convert Gram-negative bacterium into Spheroplasts. They include inhibitors of peptidoglycan synthesis such as vancomycin, fosfomycin moenomycin, lactivicin, and the B-lactam antibiotics. Antibiotics that hinder the biochemical pathways that directly lead to the synthesis of peptidoglycans trigger spheroplasts (e.g. fosmidomycin, phosphoenolpyruvate).

Alongside the above antibiotics, there are inhibitors of protein production (e.g. chloramphenicol and oxytetracycline as well as a number aminoglycosides) and inhibits of the synthesis of folic acid (e.g. trimethoprim and the sulfamethoxazole) can also cause Gram-negative bacteria to create Spheroplasts.

Treatment with penicillin

Penicillin is a B-lactam antibiotic that blocks peptidoglycan bonds during biosynthesis of the cell wall. Thus when the bacterium is subjected to this treatment it will not form a strong outer layer, and is more susceptible to pressures caused by osmotic pressures. The bacterium also forms Spheroplasts upon treatment with Lysozyme that degrades the cell’s wall. Spheroplasts may also be seen in non-lab environments and are known as “L-phase bacteria”. Different kinds that are bacterial have been discovered to be L-phase bacterium, including Pseudomonas, Staphylococcus, Clostridium and Bacillus.

2. Enzyme-induced spheroplasts

The enzyme lysozyme causes Gram-negative bacteria to form spheroplasts, but only if a membrane permeabilizer such as lactoferrin or ethylenediaminetetraacetate (EDTA) is used to ease the enzyme’s passage through the outer membrane. EDTA acts as an permeable agent through binding divalent ions, such as Ca2+ and dislodging them from the membrane’s outer.

It is believed that the yeast Candida albicans is able to be transformed into spheroplasts by using enzymes lyticase, the chitinase enzyme and b-glucuronidase.

Application of Spheroplasts

1. Antibiotic discovery

If a bacterium develops spheroplasts after treatment with drugs, the antibiotic has to work by stopping the biosynthesis of cell wall. This method has resulted in the discovery of numerous antibiotics, like cephamycin C and carbapenems as well as fosfomycin.

2. Cell lysis

The cells of yeast are typically protected by a dense cell wall, which makes the extraction of cell proteins difficult. The digestion of the cell wall by Zymolyase, which creates spheroplasts make the cells more vulnerable to lysis that is easy with detergents and rapid osmolar pressure fluctuations.

3. Patch clamp analysis

Spheroplasts that are massive (formed through the prevention in cell division) are used in the study of patch clamps, that is useful for analyzing bacteria’s Ion channels. This method records the current through an Ion channel. While a single bacterium may be too small for this test These spheroplasts, which are massive, are large enough to permit patch-clamp recording. These spheroplasts that are massive can be grown with the help of cephalexin. It keeps cells from splitting and splitting, resulting in creating “snakes” that have a distinct membrane and the cytoplasm. The cells’ walls are removed and the resulting spheroid may be used for patch-clamp study.

4. Transfection

The cell’s wall typically hinders the transfection process. consequently, by inserting Recombinant DNA inside an spheroplast, the vector is created, which allows transfection of the cells of the animal with greater effectiveness.

References

• https://www.news-medical.net/life-sciences/What-are-Spheroplasts.aspx
• https://en.wikipedia.org/wiki/Spheroplast
• https://www.microbiologyresearch.org/docserver/fulltext/micro/74/1/mic-74-1-71.pdf?expires=1644903513&id=id&accname=guest&checksum=53F55181F634CBC8D72C084A8C2B6940
• https://info.gbiosciences.com/blog/the-differences-between-a-protoplast-and-a-spheroplast-and-their-subsequent-uses