Nanobacterium sanguineum

A Microbial Biorealm page on the genus Nanobacterium sanguineum

Classification

Higher order taxa

cellular organisms; Bacteria; unclassified Bacteria; Nanobacterium

Species

NCBI: Taxonomy

Nanobacterium sanguineum

Description and significance

The genus Nanobacterium is said to contain a group of microbes that, like the name suggests, have dimensions considerably lower than that of regular bacteria, and perhaps even rival those of viruses. Since its discovery, nanobacteria have been the subject of consistent controversy; due to the significant size difference, some researchers have debated whether or not the so-called microorganisms are even alive, much less real. Only recently has it subsided, due to new studies being released.

The first discernable species of nanobacteria was dubbed Nanobacterium sanguineum in 1998 by Finnish researchers E. Olavi Kajander and Nev Ciftcioglu; together they found evidence of self-replicating nanobacteria in the blood of humans and cows, along with the presence of 16S ribosomal RNA, evidence that the microbes are indeed alive. In addition, they discovered a unique characteristic among nanobacteria; they all seemed to produce a thick cell envelope of sorts consisting of either calcium compounds or apatite. Due to this property, nanobacteria was hypothesized to be the causes of calcification in certain parts of the body (i.e. kidney stones, plaques in various organs).

However, a couple years later, it was theorized that the particles discovered may not have actually been alive or self-replicating at all. According to a paper published in 2000, the replication witnessed by Kajander and Ciftcioglu may have been due to the properties of apatite itself, and the RNA present was likely a contaminant of another bacteria.

In 2004, a paper written by John C. Lieske ey al. revealed evidence of particles similar to nanobacteria in various calcified arteries and arterial plaques. These particles not only self-replicated, but were also stained by a DNA probe, suggesting that they may contain nucleic acids, which in turn suggests that these nanoparticles may indeed be alive.

Since then, efforts in isolating nanobacteria from various places in the human body have been a moderate success; nanobacteria have been witnessed in kidney stones, the blood of humans, coronary plaques, and nanobacteria antigens have been detected in those with ovarian cancer and arthritis. Presently there is an emphasis on the pathological properties of nanobacteria and the risks and diseases it may be an indirect cause of.

Genome structure

Due to the relatively controversial nature of nanobacteria, the genome of any of the species within the genus have yet to be sequenced. However, now that evidence has been seen of nanobacteria containing nucleic acids, attempts to extract the 16S ribosomal RNA of any of its species may be the first step to sequencing the genome.

Cell structure and metabolism

Not much is known about the cell structure of species within Nanobacterium. When viewed under a electron microscope, they appear to be cellwalled microbes that are either rod-shaped or spherical, and staining attempts have indicated that, if they are indeed bacteria, they appear to be Gram negative. Nanobacteria also have the unique ability to produce a "shell" of sorts around their bodies composed of apatite or a calcium compound. The function of the "envelope" has yet to be determind.

The metabolic pathways of nanobacteria still prove to be a mystery as well, since there has yet to be infallible proof of RNA or DNA present within nanobacteria. However, one NASA study has shown that in a microgravity environment, nanobacteria seem to grow several times faster, which could serve to be a potential health risk with astronauts.

Ecology/Pathology

While nanobacteria may potentially be present practically everywhere, most have been isolated from the human body. Specifically, most particles have been located in any areas where calcification has taken place, i.e. kidney stones and coronary plaques. This suggests that nanobacteria and their calcium-coated shells are the direct cause of the production of kidney stones and such plaques. Additionally, recent evidence implies that nanobacteria may also be correlated to inflammation in various parts of the body, including cardiac valves, blood vessels, ovarian cancers, and Alzheimer's disease.

There also appears to be a strong correlation between nanobacteria and HIV infection. According to a recent study done in South Africa, the amount of anti-nanobacteria antibody was seventeen times higher in those infected with HIV than in those with relatively normal health. Such studies have proven extremely beneficial in the fight against HIV prevention, opening a door to yet another method of attack on the epidemic.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

As mentioned previously, much of the current intrigue of nanobacteria is its pathological properties, and indeed, recent research of nanobacteria confirm this interest. Studies such as the HIV study have proven to be helpful in battling such diseases and ailments.

In the HIV study in particular, researchers have suggested that the level of nanobacteria antigen present in a patient's blood may be used as a way to monitor HIV viral load in individuals. In Third World countries such as South Africa, such tests would be much more inexpensive than contemporary methods of HIV testing, and would thus be a significant boon to HIV prevention in the world.

In addition, nanobacteria has been recently hypothesized to have a hand in periodontal diseases, or diseases of the teeth and gums. The calcification of accumulated dental plaque is a principle cause of diseases such as gingivitis and periodontitis, where microorganisms become prime for infection. It's been discovered that the process of calcification of plaques is strikingly similar to that of nanobacteria; not only are the nucleating properties of calcified dental plaque similar to that of nanobacteria, but the pH conditions that are required for calcification of plaque is are also similar than that of nanobacteria. Additionally, while it may perhaps be coincidental more than logical, most periodontal diseases are treated with Tetracyclin, a relatively prominently used antibiotic which seems to be one of the only antibiotics that are particularly effective against nanobacteria.

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by Allen Park, student of Rachel Larsen