Bacteria & Archaea

## Nanoarchaeum equitans: The Smallest Living Thing

Nanoarchaeum\_equitans is the smallest known archaea, at the very limits of what is thought to be a minimal life form. It was discovered in 2002 in a hydrothermal vent off the coast of Iceland. It is an obligate symbiont of another archaean (Ignicoccus), meaning it depends upon the presence of the other host to survive.

It has no ability to synthesize nucleotides, amino acids, lipids, or most other biological substances, and depends upon its host for these.

Wikipedia entry: https://en.wikipedia.org/wiki/Nanoarchaeum\_equitans

## Thiomargarita namibiensis: The Largest Bacterium

Thiomargarita nambiensis is the world's most massive bacterium. It was discovered in 1999 off the coast of Nambia. Its cells grow as large as 3/4mm across, which makes it *visible to the naked eye.* In fact, it is about the size of the period at the end of this sentence*.*

Giganticism is usually a disadvantage for bacteria, because as its dimensions grow, its internal volume increases by a factor of 3, while its surface area only increases by a factor of 2. This makes it difficult to get nutrients in and out of the cell. Nambiensis solves this by having large vacuoles (indentations) on its cell membrane, in which it stores nitrates, which it consumes for fuel.

Wikipedia entry: https://en.wikipedia.org/wiki/Thiomargarita\_namibiensis

## Haloquadratum: Cells That are Square

 The archaeon *Haloquadratum walsbyi* ("salt squares of Walsby") was first discovered in 1980 by A.E. Walsby in the Gavish Sabkha, a coastal brine pool in the Sinai peninsula, Egypt.

It is unusual because it is square shaped, like salt crystals.

Wikipedia entry: https://en.wikipedia.org/wiki/Haloquadratum

## Mycoplasma laboratorium: The First Artificial Lifeform

Mycoplasma laboratorium was created by the J. Craig Ventner Institute in 2006. It was derived from Mycoplasma genitalium, a natural bacteria found in the urinary tract, because it had the smallest known genome at the time. Its DNA was submitted for a patent, which has tested intellectual property law around synthetic biology. It also raises ethical questions as we are now able to tamper with "life itself".

Wikipedia entry: https://en.wikipedia.org/wiki/Mycoplasma\_laboratorium

## Pelagibacter ubique: The Most Abundant Species on Earth

Pelagibacter ubique lives in the open ocean, where it represents the most abundant species on Earth. It was isolated in 2002. The total abundance of *P. ubique* and relatives is estimated to be about 200,000,000,000,000,000,000,000,000,000 microbes.

The bacteriophage virus that preys upon it may be even more numerous.

Wikipedia entry: https://en.wikipedia.org/wiki/Pelagibacter\_ubique

## Deinococcus radiodurans: The World's Toughest Bacterium

Known as "Conan the Bacterium", Deinococcus radiodurans can survive 3,000x more radiation exposure than the lethal dose for a human. It has the ability to repair its DNA more effectively than any other organism.

It can also survive extremes of cold, dehydration, vacuum, and acids. Bioengineered strains have been created that process poisons and heavy metals such as mercury.

Wikipedia entry: https://en.wikipedia.org/wiki/Deinococcus\_radiodurans

See also: http://www.genomenewsnetwork.org/articles/07\_02/deinococcus.shtml

## Geogemma barossii: Highest Temperature Tolerance

Geogemma barossii is an archaean discovered in a hydrothermal vent off of Puget Sound in 2003.  It is able to reproduce at temperatures of 250 degrees fahreinheit.  It makes a living reducing iron oxide--consuming rust.

Wikipedia entry: https://en.wikipedia.org/wiki/Strain\_121

## Sorangium cellulosum: Largest Bacterial Genome

Forms slime colonies

Creates numerous anti-bacterial and anti-fungal substances

TODO

Wikipedia entry: http://en.wikipedia.org/wiki/Sorangium\_cellulosum

## Nasuia deltocephalinicola: Smallest Bacterial Genome

Nasuia deltocephalinicola is a tiny specialized bacterium that lives in the salivary glands of a particular species of leafhopper (*Macrosteles quadrilineatus).* Its genome has only 112,000 base pairs.

See also: http://phenomena.nationalgeographic.com/2013/08/23/and-the-genomes-keep-shrinking/

Wikipedia entry: http://en.wikipedia.org/wiki/Nasuia\_deltocephalinicola

## Magnetospirillum magnetotacticum: Living Magnets

These bacteria have special organelles called magnetosomes for the purpose of aligning themselves with the Earth's magnetic field. When they ingest iron, they create tiny crystals of highly magnetic magnetite. The bacteria migrate through their environment aligned with magnetic field lines for purposes that are unclear.

 Wikipedia entry: https://en.wikipedia.org/wiki/Magnetospirillum

## Pseudomonas syringae: Living Icemakers Responsible for Rain and Snow

Pseodomonas syringae has the ability to raise the freezing temperature of water, forming ice crystals.

It is a plant pathogen, causing billions of dollars of frost damage to crops each year when it creates these ice crystals in plant bodies.

It is also found in clouds, where it is believed to nucleate ice crystals that result in raindrops.

Wikipedia entry: https://microbewiki.kenyon.edu/index.php/Bacterial\_nucleation\_in\_pseudomonas\_syringae

## Myxococcus xanthus: The Wolf Pack of the Bacterial Kingdom

When a group of Myxococcus xanthus identify potential food or prey, they send out a signal to organize the colony into an undulating mass that envelops and consumes the prey. This cooperation between bacteria represents emergent intelligent behavior from simple feedback mechanisms.

A video of the wolf pack in action: https://www.youtube.com/watch?v=tstc6doiNCU

Wikipedia entry: https://microbewiki.kenyon.edu/index.php/Myxococcus

## Desulforudis audaxviator: No Oxygen, No Light, No Problem

Desulforudis audaxviator was discovered in 2008 nearly 1.7 miles underground living in ground water at the bottom of a gold mine shaft in South Africa. It is the only life form found that is alone in its ecosystem, devoid of oxygen or light. It absorbs energy from the radioactive decay of uranium in surrounding rocks.

Wikipedia entry: http://en.wikipedia.org/wiki/Desulforudis

## Cyanobacteria: They Made the Air That You Breathe

Cyanobacteria are ancient life forms that are thought to have produced the Earth's oxygenated atmosphere billions of years ago. They were one of the first life forms to capture energy from the sun by performing photosynthesis. This significantly changed the Earth, forcing anerobic life forms into niche, rusting exposed metals, and setting the stage for oxygen-breathing life forms to evolve. Cyanobacteria are also thought to be the ancestors of chloroplasts inside plant cells, which are the organelles that perform photosynthesis.

Wikipedia entry: http://en.wikipedia.org/wiki/Cyanobacteria

## Dictyoglomus thermophilium: Bleaching Paper Without Chemicals

Thermophile ("heat-loving") bacterium discovered in a hot spring in Japan in 1985.

It is notable for producing an enzyme that can bleach wood pulp for paper without the use of chemicals.

Wikipedia entry: https://microbewiki.kenyon.edu/index.php/Dictyoglomus\_thermophilum

## Thermotoga neapolitana: Hydrogen Gas Producer

A thermophilic bacterium known for producing hydrogen gas. If it could be cultured at scale, it could produce clean hydrogen gas to be used for energy purposes. It was discovered living in geothermal springs in Italy.

Wikipedia entry: https://microbewiki.kenyon.edu/index.php/Thermotoga\_neapolitana