Difference Between Amoeba and Entamoeba

Key Difference – Amoeba vs Entamoeba
 

Amoeba and Entamoeba are two species belonging to the taxonomic group amoebozoa. They are characterized by the presence of different types of pseudopods or pseudopodia including finger-like, blunt, lobose pseudopods and tubular shaped mitochondrial cristae. Amoebozoans are unicellular organisms. Amoebozoa is classified as a phylum under the kingdom Protista. Most amoebozoa are free living, either in freshwater or marine water. Amoebozoans are either shelled (hard shell) or unshelled (naked cell) and vary in size with a typical diameter of 10-20 μm. Amoeba is free living in freshwater, marine water and soil. Entamoeba is an endoparasite which resides inside a host body. This is the key difference between Amoeba and Entamoeba. Freshwater Amoebae has a contractile vacuole, but Entamoeba does not.

CONTENTS

1. Overview and Key Difference
2. What is Amoeba
3. What is Entamoeba
4. Similarities Between Amoeba and Entamoeba
5. Side by Side Comparison – Amoeba vs Entamoeba in Tabular Form
6. Summary

What is Amoeba?

Amoeba is a unicellular organism which has a special ability to alter their shape due to the extension and retraction of pseudopodium, which is a temporary protrusion of the cytoplasm. Amoeba uses the pseudopod in order to accomplish motility and nutrient ingestion. They are basically found in major eukaryotic organisms: fungi, algae, and animals. It is the pseudopodium that helps Amoeba in movement. The pseudopod, which is a cytoplasmic extension, coordinates with actin microfilaments in order to initiate movement.

The internal structures of the pseudopod can be used to distinguish different types of Amoeba. Types of Amoeba that are free living usually occur in two forms. They either remain encased within an external hard shell or do not have a shell. A contractile vacuole which is used to maintain osmotic balance by expelling extra water is present in fresh water Amoebae. This is due to the low salt concentration present in the external environment (fresh water) when compared with the organisms’ internal environment which initiates endosmosis. In marine Amoebae, the need for such vacuole is not necessary due to the equality in concentrations of solutes between the internal and external environments.

What is Entamoeba?

Entamoeba is a unicellular eukaryotic organism which belongs to the genus Amoebozoa. Entamoeba cells are small and consist of a single nucleus and do not contain mitochondria. However, depending on the species, the number of nuclei and sizes vary. These features are useful for identification of different species. The life cycle of  Entamoeba species consists of motile, feeding and reproductive trophozoite stages and also an environmentally resistant cyst stage is present if the organism is transmitting through an infection. Entamoeba is considered as an internal parasite in vertebrates and some invertebrates. There are three species which act as parasites: Entamoeba histolytica, Entamoeba nuttalli and Entamoeba invadens. Entamoeba histolytica is a parasite present in humans while Entamoeba nuttalli is a parasite in non-human primates. Entamoeba invadens is a parasite which affects reptiles. Most Entamoeba can be considered as commensals since they do not cause diseases in the host. Entamoeba coli and Entamoeba dispar are two examples of commensals.

A major infection which is caused by Entamoeba histolytica is Amoebiasis. It is asymptomatic but, intestinal and disseminated diseases caused by E. histolytica are rare. However, the identification of E. histolytica becomes complicated as there are two other similar species namely, Entamoeba dispar and Entamoeba moshkovskii in the intestinal tract. These two species are harmless as they are considered commensals.

What are the Similarities Between Amoeba and Entamoeba?

• Amoeba and Entamoeba are unicellular organisms.
• Both organisms contain
• Both reproduce by binary fission.

What is the Difference Between Amoeba and Entamoeba?

Summary – Amoeba vs Entamoeba

Amoebozoans are unicellular organisms. They possess locomotory structures such as pseudopodia and flagella. Amoeba and Entamoeba possess pseudopods, which are extensions of the cytoplasm combined with actin microfilaments. It is used for movement and nutrient ingestion. Amoeba is free living, and the marine species possess a special contractile vacuole in order to maintain osmotic balance. They are heterotrophic organisms. Entamoeba is pathogenic and survives inside a host body. They are endoparasites. Unlike Amoeba, they do not possess a contractile vacuole. This is the difference between Amoeba and Entamoeba. They share common characteristics such as being unicellular organisms, the presence of pseudopods and reproduction through binary fission.

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References:

1. Vidyasagar, Aparna. “What Is an Amoeba?” LiveScience, Purch, 2 Apr. 2016, Available here. Accessed 22 Aug. 2017.
2. “Entamoeba and Entamoeba histolytica.” Encyclopedia of Life Sciences, Available here. Accessed 22 Aug. 2017

Image Courtesy:

1. “Amoeba (PSF)” By el:User:Kupirijo – Amoeba_(PSF).png (CC BY-SA 3.0) via Commons Wikimedia
2. “Entamoeba histolytica” By Stefan Walkowski – Own work (CC BY-SA 3.0) via Commons Wikimedia