Mycoplasma haemofelis
A Microbial Biorealm page on the genus Mycoplasma haemofelis
Classification
Higher order taxa
Bacteria; Firmicutes; Mollicutes; Mycoplasmatales; Mycoplasmataceae; Mycoplasma
Species
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NCBI: Taxonomy |
Mycoplasma Haemofelis
Description and significance
Mycoplasma haemofelis was previously known as Eperythrozoon felis or Haemobartonella felis, and it was recognized as rickettsiae until the late 90’s (1). However, as more and more researches were done on this specific bacteria, researchers realized that the classification for the bacteria had to be changed. These bacteria were parasitic, contained flagella, had small genome, and most importantly, the lack of cell wall. Therefore, researchers moved the bacteria to the class Mollicutes and the genus Mycoplasma (7). Mycoplasma haemofelis was first discovered by Flint and Moss in the United States in 1953, and they first described these bacteria as pathogens of the felines.
Mycoplasma haemofelis is a parasite that resides on the surface of red blood cell on felines, and it is about 0.5 um in diameter (1). In blood smears, the bacteria may be shaped as rings, rods or circles; sometimes they cluster together and form chains of bacteria on the surface of red blood cell (7). Further, there are three hemotropic Mycoplasmas that can infect felines: Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, and Candidatus Mycoplasma turicensis. As researches have shown, multiple infections of the above pathogens will increase the severity of the clinical signs of Mycoplasma haemofelis infection (3). The prevalence of the bacteria has been estimated among domestic cats, and the infection rate appears to be 4.9 to 23.3 %; yet the actual prevalence in not calculated because the infections are not always detectable. Common diseases caused by Mycoplasma haemofelis are feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), and feline infectious peritonitis, and most importantly, feline infectious anemia (FIA) (1, 5). However, due to several metabolism pathways, the bacteria are hard to cultivate in labs, and they often contaminate other eukaryotic cultures (6). Details will be explained in the [Cell structure and Metabolism] section down below.
Genome structure
Mycoplasma haemofelis’ linear chromosome has an average of 1,199 kb with the standard deviation of 13.5 kb. The size fits well in the range or 580 to 1,400 kb for the genus Mycoplasma. 75 new genes were identified by running the sample with random sequencing, and these genes had never been reported or discovered for Mycoplasma haemofelis or other mycoplasma. Like all mycoplasma, which have a G+C (guanine-cytosine) percentage of below 50 %, Mycoplasma haemofelis has a G+C percentage of 38.5 %. Escherichia coli strain DH10B and the vector pBeloBAC11 can be used to create the bacterial artificial chromosome (BAC) library for Mycoplasma haemofelis. 430 never-before-seen genome survey sequences (GSS) were discovered by studying the BAC, and these sequences have already been added to the database of GenBank (2).
Mycoplasma haemofelis is unique compare to other mycoplasmas, and one of the reasons is that these bacteria contain the superoxide dismutase (SOD) gene while others do not. However, the SOD gene has not been fully studied and sequenced. Two other genes in particular interest many researchers because the enzyme activities of these genes were largely unknown in Mycoplasma haemofelis. One of the gene is related to purine biosynthesis, and the other one encode proteins that are closely related to inosine-5’-monophosphate dehydrogenase and guanosine-3’, 5’-monophosphate synthase (2).
Cell structure and metabolism
Mycoplasma haemofelis have filaments with special polar tips that help the bacteria attach to the hosts. These tips were formed by complex network of protein, designated adhesins, and adherence-accessory proteins. It is because of this tips that the bacteria are able to colonize on the surface eukaryotic cells (6).
Because of the small genome, Mycoplasma haemofelis is completely dependent on the host for nutrients and survival. With no cell wall components, Mycoplasma haemofelis has a unique plasma membrane that contains sterol, and the bacteria obtain the sterol from the host in the form of cholesterol. Further, Mycoplasma haemofelis must acquire most of the biosynthetic precursors from the host, for example, nucleotides, amino acids, cholesterol, and fatty acids. Consequently, this pathogen is hard to cultivate in a lab setting because of the bacteria’s highly demand for hosts, and yet it remain as one of the top contamination to other eukaryotic cells and tissue cultures (6). On the other hand, by being a parasite on the surface of red blood cell, Mycoplasma haemofelis can obtain the most nutrients from the host and grow in to large colonies. As studies have shown, although the bacteria are cell surface parasites, they do not penetrate the cell (7).
Ecology
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Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
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Current Research
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References
Edited by student of Rachel Larsen
