Vampirococcus
Jesse Irwin

I chose Vampirococcus for my microbe of the week. Initially I picked this microbe because the name sounded interesting, but as I began researching Vampirococcus I found that it is quite an interesting organism. It is one of the few bacteria that are actually predatory, meaning that they are not simply parasitic, but actually attack and consume their prey. Also, the nature and characteristics of Vampirococcus has many implications in both evolution and ecological terminology.

We begin with an overview of Vampirococcus. As the name implies, Vampirococcus is a coccus, which in and of itself is not really that spectacular. The uniqueness of Vampirococcus starts in its metabolism. Vampirococcus is mainly aerobic however it can grow in an anaerobic environment as opposed to the other predatory bacteria which are strict aerobes. Vampirococcus exists freely in water in freshwater sulfur lakes among the lower levels of purple sulfur bacteria. While it does exist freely, Vampirococcus only multiplies when attached to its prey.

The predatory nature of Vampirococcus is quite a fascinating process. Vampirococcus “feeds” off of a group of phototrophic purple sulfur bacteria called Chromatium. Vampirococcus is an opportunistic epibiont. This means that it remains outside of its prey while consuming it as opposed to other predatory bacteria that eat their prey from the inside and it only attacks when there are unfavorable environmental conditions for its prey. This is why Vampiorcoccus is present in higher concentration at the lower levels of the Chromatium layer in water where conditions are worse for the growth of Chromatium. Once Vampirococcus comes in contact with a prey cell, an attachment structure forms to bind Vampirococcus to its prey. As it begins feeding a break in the outer membrane of Vampirococcus appears and plaque develops around the attachment site. Vampirococcus then begins to degrade the cytoplasm of its prey. Vampirococcus begins to multiply, forming multicellular arrangements, while it degrades the victim’s cytoplasm. When Vampirococcus is finished feeding, all that remains of the victim is the cell wall, cell membrane and some intracytoplasmic inclusions.

Finally, we come to the Vampirococcus’ implication in both evolution and ecological terminology. From an evolutional standpoint s is remarkable and demonstrates a predatory role among prokaryotes. This trait was thought to belong only to eukaryotic ecosystems and was thought not to exist in the prokaryotic world. However, the actions of Vampirococcus and the other predatory bacteria suggest that the prokaryotes also have predator/prey dynamic in certain microbial systems. On the same line, the terminology used to describe the relationship of Vampirococcus with its prey has been the subject of much debate. Originally, Vampirococcus and the other predatory bacteria were labeled as parasites. However, once one starts to look at the actual activity of the predatory bacteria it becomes more likely that they are primary consumers.

Probably the biggest implication that Vampirococcus has on evolution is its role in the theory of endosymbiotic theory. The belief that the organelles of the eukaryotes are derived from symbiosis of prokaryotic organisms is a widely held belief among biologists. However, some speculation exists as too how the organisms actually began their symbiotic relationship. Since phagocytosis and pinocytosis are absent in the prokaryotic world, how did the original symbiont get into that first prokaryote? The actions of the predatory prokaryotes may just be the answer. They posses the ability to actively make holes in the membranes of living prokaryotes. This leads to the possibility that either a predatory bacteria or a relative of the predatory bacteria may be responsible for the development of the organelles of the eukaryotes.

Vampirococus is truly a magnificent organism. Along with the other predatory bacteria they have accomplished much in changing the way we think about how the microbial ecosystems work as well as the terminology we use to describe these wonderful creatures. Their possible role in explaining one of the most significant events in evolution (the presence of organelles in the eukaryotes) cannot be overlooked either. Whether the predatory bacteria themselves are responsible for the presence of organelles or some relative of these microorganisms is the culprit, they still give us insight into a possibility of how the first organelles appeared in the eukaryotes. This truly makes Vampirococcus one of the most interesting microbes out there.

References

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=323246

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.

 

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