Key Difference – Mycoplasma vs Bacteria
Bacteria are unicellular microorganisms. They are referred as prokaryotic organisms since they do not possess a membrane-bound nucleus and organelles. Bacteria belong to one major domain in three domain classifications. They are ubiquitous and have many genera. Mycoplasma is a unique genus among them in which bacteria do not contain a cell wall around the cell membrane. Therefore, mycoplasma can be referred as wall-less bacteria. The key difference between bacteria and mycoplasma is that bacteria contain a cell wall and have a definite shape while mycoplasma lacks a cell wall and a definite shape.
CONTENTS
1. Overview and Key Difference
2. What is Mycoplasma
3. What is Bacteria
4. Side by Side Comparison – Mycoplasma vs Bacteria
5. Summary
What is Mycoplasma?
Mycoplasma is a genus of bacteria in which all species lack a cell wall around the cell membrane. Cell wall decides the shape of the organism. Since mycoplasma does not contain a cell wall, they do not possess a definite shape. They are highly pleomorphic. The genus mycoplasma belongs to gram-negative, aerobic or facultative aerobic bacteria. There are about 200 different species in mycoplasma genus. Among them, few species cause diseases in human. Four species have been recognized as human pathogens which cause significant clinical infections. They are Mycoplasma pneumoniae, Mycoplasma hominis, Mycoplasma, genitalium, and Ureaplasma species. Mycoplasma is the smallest bacteria discovered yet with the smallest genomes and a minimum number of essential organelles.
Mycoplasma species can’t be easily destroyed or controlled by common antibiotics such as penicillin or beta-lactum antibiotics which target cell walls. Their infections are persistent and hard to diagnose and cure. Mycoplasma contaminantes cell cultures, causing serious problems in research laboratories and industries.
Figure 01: Mycoplasma spp.
What is Bacteria?
Bacteria are single cell prokaryotic organisms. They were among the first organisms that appeared on earth. They are omnipresent since they can live on soil, water, air and even inside other organisms. Bacteria possess a simple internal structure with a free floating single chromosome genome. Some bacteria contain extra-chromosomal DNA called plasmids. Bacteria contain a cell wall which protects them from environmental threats. Some bacteria bear an extra outermost cover called capsule which provides additional protection to bacteria. Bacteria do not possess specialized cellular structures or membrane bound organelles. Motile bacteria possess flagella for locomotion. Bacteria possess small thread-like structures called pili around the cell. Ribosomes are present in bacteria as the site of mRNA translation and protein synthesis, which are necessary for growth and reproduction.
Three distinct shapes can be identified within bacteria: round shape (coccus), rod shape (bacillus) and spiral shape (spirillum).
Bacteria can divide rapidly by binary fission. Binary fission is the most common asexual reproductive mechanism shown by bacteria for multiplication. In addition, bacteria use a sexual reproduction method called conjugation as well.
Some bacteria cause diseases to humans and other animals. However, some bacteria are beneficial. They are important for agriculture, medicine, biotechnology, ecology, food industry, etc. They also help decomposition of waste and recycling nutrients.
Figure 02: Bacteria under phase contrast microscope
What is the difference between Mycoplasma and Bacteria?
Mycoplasma vs Bacteria |
|
| Mycoplasma is a bacterial genus which does not contain a cell wall. | Bacteria are microscopic organisms found everywhere on earth. |
| Shape | |
| They are mostly spherical to filamentous. | Bacteria shows different shapes such as coccus, bacillus, and spirillum. |
| Change in the Shape | |
| Mycoplasma is highly pleomorphic. They do not possess a definite shape. | Bacterial cell possesses a definite shape due to the presence of a rigid cell wall. |
| Size of the Genome | |
| Mycoplasma is considered as the smallest bacteria with small genomes. | Bacterial genome size varies according to the species. |
Summary – Mycoplasma vs Bacteria
Bacteria are one type of microorganisms. They are single cell prokaryotic organisms, possessing simple cell structures. They lack membrane-bound nucleus and organelles. Bacteria contain a prominent cell wall around the cell membrane. However, one bacterial genus called mycoplasma do not contain cell wall surrounding their cells. Therefore, these bacteria are known as cell wall deficient bacteria. This is the main difference between mycoplasma and bacteria.
References
1. Razin, Shmuel. “Mycoplasmas.” Medical Microbiology. 4th edition. U.S. National Library of Medicine, 01 Jan. 1996. Web. 17 May 2017
2. “Bacteria.” Wikipedia. Wikimedia Foundation, 12 May 2017. Web. 17 May 2017. https://en.wikipedia.org/wiki/Bacteria
3. Balish, M. F., and D. C. Krause. “Mycoplasmas: a distinct cytoskeleton for wall-less bacteria.” Journal of molecular microbiology and biotechnology. U.S. National Library of Medicine, n.d. Web. 17 May 2017
Image Courtesy:
1. “Mycoplasma pneumoniae” by AJC1 (CC BY-SA 2.0) via Flickr
2. “Bacteria (259 05)” By Doc. RNDr. Josef Reischig, CSc. – Author’s archive (CC BY-SA 3.0) via Commons Wikimedia
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