Endospore vs. Exospore

Main Difference

The main difference between Endospore and Exospore is that Endospore is formed in the parent cell wall and set free to the environment when cell rupture, whereas Exospore is formed through the cell division and is parted from the mother cell through the formation of the septum.

Difference Between Endospore and Exospore

Comparison Chart

Endospore vs. Exospore

An endospore is considered as a structure that is produced by the bacteria consisting of DNA and a small amount of cytoplasm to survive under unfavorable conditions; on the other hand, Exospore is considered as an asexual spore that is detached from the mother cell through the formation of a septum. Bacteria are responsible for producing the endospores, while fungi and algae produce the exospores.

Endospores usually are formed inside the parent cell; on the contrary, exospores are generally formed near the termination of a parent cell. Cell division does not occur in the formation of endospores; conversely, exospores are formed by the process of cell division. The structure of the endospore is sturdy, dormant, and non-reproductive, which is sometimes covered by a thin covering known as exosporium. In contrast, the structure of the exospore contains a unique form of spores, which is a means for the multiplication of bacteria and fungi, and they do not consist of special covering.

Through the rupturing of the parental cell, the endospores are released into the environment; on the other hand, the exospores are typically released through the budding. One organism can form only one endospore, but on the contrary, one organism can produce several exospores.

Endospores can be formed by the bacterial genera such as Clostridium, Bacillus, and Paenibacillus; on the flip side, exospores are formed by the Chamaesiphon, conidiospores, Actinomyces, Stichosiphon, Streptomyces, Actinobacteria. Endospores are generally produced by the Clostridium Bacillus and Sporosarcina bacteria, while on its comparison, the exospores are usually produced by some members of the phylum Actinobacteria.

What is Endospore?

An endospore is known as a resistant structure that is produced by bacteria to endure under severe and unfavorable conditions containing DNA and a little portion of the cytoplasm. An endospore is covered by a thin layer of the protective outer covering.

When many environmental conditions become favorable, the endospores started to germinate and form many new organisms. That is why endospores are referred to as the primary type of reproductive cells. Endospores are formed by bacterial genera such as Clostridium, Bacillus, and Paenibacillus. These bacterial genera can endure harsh conditions like high and low temperatures, UV radiations, dehydration, chemicals.

The Endospore contains a cell wall that is formed of dipicolinic acid, which provides heat resilient properties to the endospore. The bacterial endospores can be destroyed by the treatment of moist heat at 121 °C for about 15 minutes.

The name “endospore” is given, which means a spore or seed-like shape, but it is not considered as a true spore. The endospore is a tough, dormant, stripped-down structure from which the bacteria can moderate itself. The formation of endospore is customarily triggered when there is a lack of nutrients and mainly happens in gram-positive bacteria.

What is Exospore?

The exospore is known as one more resilient bacterium, which is mainly formed by algae and fungi to multiply in harsh environmental circumstances. Through the process of cell division, the exospores produce at the terminal point of the parent cell.

The exospore can be separated by the production of a septum, which occurs between the parent and the daughter cell—the exospore results in the shape of a bud. The bud can be released from the parent cell for its germination when favorable conditions come. The conidiophores are known as kinds of fungal spores, which are generally formed as exospores.

The exospores are produced by algae such as Stichosiphon and Chamaesiphon. The exospores can also be produced by bacteria such as Actinomyces, Streptomyces, and Actinobacteria. The cyanobacteria, such as Chamaesiphon, also results in the formation of exospores. The exospore is the permanent structure of single types of bacteria.

The exospores do not have a protective covering of a spore shell. Because of almost entirely adjusted metabolism of exospores and their low water content, the exospores are considered more resilient to intense heat, dehydration, chemical stress, and radiation as compared to the vegetative cell. The exospore producer is, for instance, the methane, which is typically using bacterial genus Methylosinus.

Conclusion

The above discussion concludes that Endospore and Exospore are two types of spores. Still, they are different from each other as Endospore is primarily produced by bacteria and inside the parent cell. Exospore is formed by algae, fungi, bacteria, and cyanobacteria and produced at the end of the parent cell.