''Spirochaeta americana'' is a single-celled

extremophile An extremophile (from Latin ' meaning "extreme" and Greek ' () meaning "love") is an organism that is able to live (or in some cases thrive) in extreme environments, i.e. environments that make survival challenging such as due to extreme temper ...

. This

halo Halo, halos or haloes usually refer to: * Halo (optical phenomenon) * Halo (religious iconography), a ring of light around the image of a head HALO, halo, halos or haloes may also refer to: Arts and entertainment Video games * ''Halo'' (franch ...

alkaliphilic Alkaliphiles are a class of extremophilic microbes capable of survival in alkaline ( pH roughly 8.5–11) environments, growing optimally around a pH of 10. These bacteria can be further categorized as obligate alkaliphiles (those that require high ...

and obligately anaerobic bacterium can be found in the highly alkaline, salty, deep waters of

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

Mono Lake Mono Lake ( ) is a saline soda lake in Mono County, California, formed at least 760,000 years ago as a terminal lake in an endorheic basin. The lack of an outlet causes high levels of salts to accumulate in the lake which make its water alk ...

Physical characteristics

''S. americana'' has long helically coiled cells, is

gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

, and is

chemotroph A Chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic ( chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototro ...

ic in its

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

. Spirochaeta also have unique

flagella A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

, sometimes called ''axial filaments'', which run lengthwise between the

cytoplasmic membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment ( ...

and outer membrane. These cause a twisting motion which allows the spirochaete to move about. Despite the extreme environment that they require, "their cell walls are very delicate, and it is difficult to keep them alive for long periods in the laboratory," says Dr.

Elena Pikuta Elena may refer to: People * Elena (given name), including a list of people and characters with this name * Joan Ignasi Elena (born 1968), Catalan politician * Francine Elena (born 1986), British poet Geography * Elena (town), a town in Veliko ...

, one of the discoverers of ''S. americana''.

Environment

''S. americana'' thrives in the lake-bottom mud of Lake Mono, a 13 mile wide former

monomictic Monomictic lakes are holomictic lakes that mix from top to bottom during one mixing period each year. Monomictic lakes may be subdivided into cold and warm types. Cold monomictic lakes Cold monomictic lakes are lakes that are covered by ice throu ...

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

basin which is fed by numerous small Sierra streams and which has no outflow except

evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...

and Californian aqueducts, thereby continually increasing the concentration of salts and other minerals in its waters. Further mineral enrichment of these waters also occur due to the volcanically active area, such as when

Negit Island Negit Island is an island in Mono Lake. Negit (along with nearby Paoha Island) is a volcanic cone less than 2000 years old. It can be considered to be the northernmost of the Mono Craters. Negit is composed of three dark dacite lava flows. Neg ...

erupted roughly 250 years ago. Surviving in deep, salty, alkaline lake mud of Lake Mono, the extreme conditions in which ''S. americana'' thrive have prompted its discoverers to explore

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

Lake Untersee Lake Untersee (german: Untersee, "Lower Lake") is the largest surface freshwater lake in the interior of the Gruber Mountains of central Queen Maud Land in East Antarctica. It is situated to the southwest of the Schirmacher Oasis. The lake i ...

, hopefully to discover similar species.

Reproduction

''S. americana'' reproduces via transverse binary fission, where the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

divides transversely between two sets of DNA genomes, forming two dissimilar individuals, as do other Spirochaeta.

Growth and metabolism

This bacterium grows in environments of 10 to 44 degrees

Celsius The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The ...

with optimal growth at 37 degrees and prefers a pH balance of 9.5, similar to that of baking soda, hand soap, or a solution of household bleach in water. ''S. americana'' is capable of metabolizing

D-glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis f ...

fructose Fructose, or fruit sugar, is a Ketose, ketonic monosaccharide, simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galacto ...

maltose } Maltose ( or ), also known as maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) bond. In the isomer isomaltose, the two glucose molecules are joined with an α(1→6) bond. Maltose is the two- ...

sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...

and

D-mannitol Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lower ...

and has as its waste H₂,

acetate An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

and

formate Formate (IUPAC name: methanoate) is the conjugate base of formic acid. Formate is an anion () or its derivatives such as ester of formic acid. The salts and esters are generally colorless.Werner Reutemann and Heinz Kieczka "Formic Acid" in ''Ull ...

References

External links

Science a gogo - New Species Of Organism Excites AstrobiologistsType strain of ''Spirochaeta americana'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{DEFAULTSORT:Spirochaeta Americana Halophiles Alkaliphiles Spirochaetes Bacteria described in 2003