Three Microbes

Continuing with my previous "Three Microbes" posts, I've stumbled across some more eccentric microbes lately!

Salinibacter ruber
It's often difficult to find life in saturated thalassic (deep-sea) brines, but one bacteria that can survive in such high salinities is called Salinibacter ruber. S. ruber was initially discovered in ponds in Spain (specifically in Alicante and Mallorca) that had extremely high concentrations of salt. Basically, it's a salt lover! This orange-red and rod-shaped bacterium has been found "repeatedly in significant numbers in climax saltern crystallizer communities." Large populations of this bacteria can often turn whole ponds and bodies of water red.

Vibrio fischeri is found commonly in the ocean, and especially in certain light organs of the squid Euprymna scolopes. What makes this bacteria really neat is its bioluminescent properties! When many Vibrio fischeri cells lump together at a high concentration in specialized light organs of the squid, they produce an autoinducer. As a result, they emit a really strong blue-green light. This light actually works in the favor of the squid that houses the Vibrio fischeri. During the day, the squid expels the bacteria from its light organs into the surrounding water. During the night, however, when the squid feeds, it takes up the bacteria. The squid then uses the light that the bioluminescent Vibrio fischeri produce to counteract the "shadowing effect the moon makes," thereby masking it from squid-eating predators.

Vampirococcus

Vampirococcus is a predatory prokaryote that has some pretty frightening ways to obtain nutrition. When it requires nutrients, it tends to attach itself to a larger purple sulfur phototrophic bacterium called Chromatium, similar to a vampire sucking blood. Once attached to the Chromatium cell, it sucks out the bacteria's cellular components - particularly the cytoplasm - and effectively kills it using digestive enzymes. I don't know about you, but I wouldn't want to be a Chromatium bacterial cell! Scientists are currently contemplating the use of Vampirococcus in agriculture in a predatory way to attack bacteria (similar to how fungi are used currently). Current research also points to the use of Vampirococcus as a way to combat tumors.

References

Anton, J. Salinibacter ruber gen. nov., sp. nov., a novel, extremely halophilic member of the Bacteria from saltern crystallizer ponds. Int J Sys Evol Microbio. 52, 485-91. (2002).

Dewaswala, M. Vampirococcus.

Guerrero, R., Pedros-Alio, C., Esteve, I., et. al. Predatory prokaryotes: Predation and primary consumption evolved in bacteria. Proc Natl Acad Sci USA. 83, 2138-2142. (1986).

Mongodin, EF. The genome of Salinibacter ruber: convergence and gene exchange among hyperhalophilic bacteria and archaea. Proc Natl Acad Sci USA. 102, 18147-52. (2005).

Walsh, A. Quorum Sensing in Vibrio Fischeri. CMU (2014).

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