For being the smallest known phototrophs, the Prochloroccus bacteria play a huge role in the global carbon cycle. These are responsible for 20% of the world’s atmospheric oxygen, as well as 30-80% of “primary production in…oligotrophic oceans…” (Microbewiki). In terms of the oceanic food chain, these provide the foundation for it. The produce more cells very quickly, and thus provide a good chemical food source for other microscopic bacteria.
When it was assumed that Prochlorococcus and Prochloron were closely related due to their chlorophyll-b-containing properties, prochlorococcus was named to represent this relation. Now we know there are many differences between these two, and prochlorophytes have their own subgroups under cyanobacteria.
Prochlorococcus marinus is found most readily in temperate and tropical oceans, and is one of the most prevalent photosynthetic, oxygen-evolving organisms in the world. They are found in the upper area of water closest to the sun, where they get their food. In one drop of seawater, there may be up to 20,000 prochlorococcus cells.
In 1986, Prochlorococcus was found by a group of scientists using flow cytometry Sallie Chisolm and Robert J. Olsen were a leading part of this group who discovered it in the Sargasso Sea, because of its unique characteristic of emitting red light (due to its chlorophyll a and b, a-carotene, and zeaxanthin derivatives). As far as is known, this is the only species to contain all these pigments. This made it easy to identify as a new bacteria. The pigments allow the bacteria to “absorb blue light efficiently as low light intensities” (Microbewiki).
Prochlorococcus Marinus gets its energy from a few different sources. The bacteria that live near the surface of the ocean get most of their energy from sunlight. However, there are others that live in the deeper parts of the water, and they have a metabolism mostly based on carbon and oxygen.
P. marinus is a prokaryotic cell, so it stains Gram positive, as a Gram positive cell.
This bacteria is not harmful to humans, so it does not have any specific characteristics to avoid detection by a host. In fact, it is very helpful to plant and sea life because it is photosynthetic. It is perfectly designed for taking in light and turning it into food for other microorganisms. Usually characteristic of photsynthetic organisms like these are phycobilisomes, a light-harvesting antennae. However, the P. marinus species does not have this, but instead, contains chlorphyl b to do this job. This makes it unique from other organisms, but still provides it with the accessory it needs to do its intended job.
In the laboratory, you could grow Prochlorococcus by creating the environment to these specifications: Start with a stock culture; temperature should be about 24 degrees Celsius. The strains should be kept under a special light cycle that resembles the sunlight in the ocean. The media used is that of the Sargasso Sea water, enriched with ammonium chloride, an acid, and some trace metals like Zinc, Cobalt, Manganese, Nickel, and Iron.
Work Cited
MicrobeWiki. Kenyon College, 3 Feb. 2012. Web. 25 Feb. 2012.
"P. Marinus." JGI Genome Portal. University of California, 23 Aug. 2001. Web. 03 Mar. 2012.
Chisholm, Sallie W. "Research Abstracts 2000 DOE Human Genome Program." Oak Ridge
National Laboratory. Massachusetts Institute of Technology, 2 Mar. 2000. Web. 06 Mar. 2012. http://www.ornl.gov/sci/techresources/Human_Genome/publicat/00santa/125.html.
Sullivan, Matthew B. "Cyanophages Infecting the Oceanic Cyanobacterium Prochlorococcus." Asean Biodiversity. Nature Publishing Group, 28 Aug. 2003. Web. 6 Mar. 2012.
Moore, Lisa R. "Utilization of Different Nitrogen Sources by the Marine Cyanobacteria Prochlorococcus and Synechococcus." American Society of Limnology and Oceanography, 2002. Web. 6 Mar. 2012. http://new.aslo.org/lo/toc/vol_47/issue_4/0989.pdf.
great job! Love it!
ReplyDeleteThis looks good, but you're incorrect on one point: not all prokaryotes stain gram-positive. There are plenty of gram-negative bacteria. P. Marinus is actually a gram-negative bacteria.
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