Kakabekia barghoorniana

Classification

Kingdom: Plantae

Phylum: Plantaeincertaesedis

Class: Unclassified

Order: Unclassified

Family: Unclassified

Genus: Kakabekia

Species: Kakabekia barghoorniana

The name Kakabekia references the region in Ontario where the microfossil relative Kakabekia umbellata was first discovered. The name barghoorniana refers to the scientist, Barghoorn, who discovered the microfossil. Kakabekia is not well differentiated phylogenetically, but it is believed to be the modern descendent of one of the first Eukaryotes in the Plant kingdom.

Description and Significance

Kakabekia barghoorniana was first described by Sanford Siegel in 1966 (it was first seen in culture in 1964) as a living organism that appeared nearly identical to a microfossil that had been discovered in Ontario which had been thought to have no relationship to any currently living species by a Harvard paleontologist Elso Barghoorn. The fossil was found in the gunflint range chert deposits that date back to the middle Precambrian period in what woiuld have likely been shallow lakes (cite main article). K. barghoorniana was first found in a high ammonium soil sample from Wales and was subsequently isolated from high ammonium environments in Alaska. Subsequently, Kakabekia was isolated from soil samples near the edge of a glacier in Iceland; the species is at least cold-tolerant. The soil from which Kakabekia was cultured was high in content of carbon, hydrogen, and organic nitrogen with low levels of sodium, potassium, and titanium. Kakabekia can be grown in glucose free media but growth is slowed significantly. Even with other nitrogen sources, Kakabekia cannot be grown without ammonia (Living relative article).

K. barghoorniana is a umbellate microbe that is not fully classified. The structure was initially described without distinct nuclei, however subsequent research revealed that the microbe is actually a eukaryote of the kingdom plantae. Structurally, the organism has a mantle with multiple rays that forms the top of the "umbrella" with a slender stalk leading to a sphrerical bulb (main article). The organism is oxygen indifferent, with few heme enzymes and no phenol oxidases. Furthermore, the species has absolutely no ability to store lipid or polysaccharide (main article). Kakabekia appears to preferentially utilize glucose as a carbon and energy source but it has the ability to function without; likely through photosynthetic machinery.

K. barghoorniana was discovered during research attempting to isolate organisms that could survive in high ammonia environments. This is of particular interest to astro-biology; for example multiple gas giant/moons have atmospheres with very high ammonium content. Kakabekia is also a living relative of a Precambrian microfossil and provides a model organism that would have survived and flourished in the primative, reducing environment of the Precambrian era.

Genome Structure

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Metabolism

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Ecology

The ecologic makeup of the community the modern species Kakabekia barghoorniana occupies is not fully elucidated in the research. Given the unusual conditions, the lack of mention of other organisms could simply represent the inability to grow and/or identify other members of the community; also the research was not directed at identifying the entire ecological niche, more with defining the growth of a relative of a primordial species. In the precambrian era, Kakabekia lived in stromatolite communities consisting of blue-green algae, multiple bacterial species, and the partially characterized Eosophaera another primitive eukaryote. Ancient Kakabekia lived with what were most likely iron-oxidizing bacteria in the benthic regions of the sea floor of ferruginous oceans in a very high iron, anoxic environment. This likely correlates to the oxygen-indifference of modern Kakabekia. The modern Kakabekia lives in a fairly similar environment, thought the community surrounding it is not well described it likely bears some resemblence to that of it's precambrian ancestor. (gustavus article) (also correlated from the original seigel article)