23 Questions
What is the defining characteristic of Mycoplasma bacteria?
They lack a cell wall around their cell membranes and peptidoglycan (murein) is absent.
Why are Mycoplasma bacteria naturally resistant to certain antibiotics?
They are resistant to antibiotics that target cell wall synthesis because they lack a cell wall.
What are two pathogenic species of Mycoplasma in humans and the diseases they are associated with?
M. pneumoniae is associated with 'walking' pneumonia and other respiratory disorders, while M. genitalium is believed to be involved in pelvic inflammatory diseases.
What is the classification of Mycoplasma in the scientific classification system?
Mycoplasma refers exclusively to the genus, a member of the Mycoplasmataceae, the only family of the order Mycoplasmatales.
What is the evolutionary relationship between Mycoplasma mycoides and the genus Spiroplasma?
Mycoplasma mycoides is evolutionarily more closely related to the genus Spiroplasma in the order Entomoplasmatales.
What would be the potential consequence of rearranging the group to match phylogeny, according to the text?
Medically important species such as M. pneumoniae and M. genitalium would have to be put in a different genus, causing widespread confusion in medical and agricultural communities.
How many nontaxonomic lineages can Molicutes be divided into, according to the text?
Molicutes can be divided into four nontaxonomic lineages.
What are the three groups under which medically important species are classified within the nontaxonomic lineages of Molicutes?
The three groups are 'Acholeplasma' group, 'Spiroplasma' or mycoides group, and pneumoniae group.
Which medically important species are included in the pneumoniae group?
M. alvi (bovine), M. amphoriforme (human), M. gallisepticum (avian), M. genitalium (human), M. imitans (avian), M. pirum (uncertain/human), M. testudinis (tortoises), and M. pneumoniae (human).
What were the changes made to the taxonomy of the genus Mycoplasma by Gupta et al. in 2018?
A total of 78 species was removed from Mycoplasma, creating five new genera and a number of higher taxonomic levels. A new family Mycoplasmoidaceae was created to correspond to the 'pneumoniae' group, with M. pneumoniae and related species transferred to a new genus Mycoplasmoides. Another new family Metamycoplasmataceae was created to correspond to the 'hominis' group.
Under the new taxonomy proposed by Gupta et al. in 2018, what new order was created, distinct from the Mycoplasmatales of Mycoplasma?
A new order Mycoplasmoitales was created, distinct from the Mycoplasmatales of Mycoplasma.
When was the taxonomy proposed by Gupta et al. in 2018 accepted by the International Committee on Systematic Bacteriology (ICSB)?
The taxonomy was accepted by the ICSB with validation list 184 in 2018 and became the correct name.
Who first used the term 'mycoplasma' and for what purpose?
Albert Bernhard Frank used the term 'mycoplasma' in 1889 to describe an altered state of plant cell cytoplasm due to infiltration by fungus-like microorganisms.
Who initially proposed the term 'mycoplasma' and how did they describe the microorganisms?
Julian Nowak initially proposed the term 'mycoplasma' for certain filamentous microorganisms with cellular and acellular stages, visible with a microscope but impermeable to filters.
What was the original name for mycoplasmas and why was it chosen?
The original name for mycoplasmas was pleuropneumonia-like organisms (PPLO), chosen for their similarity to the causative agent of contagious bovine pleuropneumonia.
How many species are included in the genus Mycoplasma, and what class do they belong to?
Over 100 species are included in the genus Mycoplasma, which is a member of the class Mollicutes.
What hosts do Mycoplasma species parasitize or exist as commensals in?
Mycoplasma species are parasites or commensals of humans, animals, and plants, using vertebrate and arthropod hosts.
What is the size range of Mycoplasma species, and where have they been found in cattle suffering from pleuropneumonia?
Mycoplasma species are about 0.2 - 0.3 µm in diameter and have been found in the pleural cavities of cattle suffering from pleuropneumonia.
What are some unique characteristics of Mycoplasma species?
Mycoplasma species lack a cell wall, have a single DNA duplex and 70S type ribosomes, and can contort into various shapes due to the lack of a rigid cell wall.
How do Mycoplasma species reproduce, and how is this mechanism observed?
Mycoplasma species reproduce by a uni- or multi-polar budding mechanism, observed through phase-contrast microscopy and electron microscopic studies.
What were Mycoplasma species previously considered to be, and what has phylogenetic analysis revealed about them?
Mycoplasma species were previously considered stable L-form bacteria or even viruses, but phylogenetic analysis has identified them as bacteria that have lost their cell walls.
What is the etymology of the name 'Mollicutes' and what is the significance of this name?
The name 'Mollicutes' is derived from the Latin Mollis (soft) and cutis (skin), signifying that all of these bacteria lack a cell wall and the genetic capability to synthesize peptidoglycan.
What is the oldest and largest genus of the class Mollicutes, and how are its species typically distributed?
The oldest and largest genus of the class Mollicutes is Mycoplasma, with about half of the class' species, usually limited to a specific host and distributed among at least three separate orders.
Study Notes
Understanding Mycoplasma: Etymology, Species, Pathophysiology, Characteristics, Reproduction, and Taxonomy
- The term "mycoplasma" was first used by Albert Bernhard Frank in 1889 to describe an altered state of plant cell cytoplasm due to infiltration by fungus-like microorganisms.
- Mycoplasma was initially proposed by Julian Nowak for certain filamentous microorganisms with cellular and acellular stages, visible with a microscope but impermeable to filters.
- The name for these mycoplasmas was pleuropneumonia-like organisms (PPLO), referring to organisms similar to the causative agent of contagious bovine pleuropneumonia.
- Mycoplasma refers solely to the genus at present, and over 100 species are included in the genus Mycoplasma, a member of the class Mollicutes.
- Mycoplasma species are parasites or commensals of humans, animals, and plants, using vertebrate and arthropod hosts.
- Mycoplasma species are among the smallest free-living organisms, about 0.2 - 0.3 µm in diameter, and have been found in the pleural cavities of cattle suffering from pleuropneumonia.
- Mycoplasma species lack a cell wall and have a single DNA duplex and 70S type ribosomes, with a replicating disc at one end.
- Mycoplasma species can contort into various shapes due to the lack of a rigid cell wall and cannot be identified as rods, cocci, or spirochetes.
- Mycoplasma species reproduce by a uni- or multi-polar budding mechanism, observed through phase-contrast microscopy and electron microscopic studies.
- Mycoplasma species were previously considered stable L-form bacteria or even viruses, but phylogenetic analysis has identified them as bacteria that have lost their cell walls.
- The name "Mollicutes" is derived from the Latin Mollis (soft) and cutis (skin), and all of these bacteria lack a cell wall and the genetic capability to synthesize peptidoglycan.
- The oldest and largest genus of the class Mollicutes is Mycoplasma, with about half of the class' species, usually limited to a specific host and distributed among at least three separate orders.
Test your knowledge of Mycoplasma with this quiz covering its etymology, species, pathophysiology, characteristics, reproduction, and taxonomy. Learn about the fascinating world of these small, wall-less bacteria that can parasitize and coexist with humans, animals, and plants.
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