''Prymnesium parvum'' is a species of

haptophyte The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for '' Prymnesium''), are a clade of algae. The names Haptophyceae or Prymnesiophyceae are sometimes used instead. This ending implies classification at ...

s (also collectively called Prymnesiophyta). The species is of concern because of its ability to produce the phycotoxin

prymnesin Prymnesin may refer to: * Prymnesin-1 * Prymnesin-2 Prymnesin-2 is an organic compound that is secretion, secreted by the haptophyte ''Prymnesium parvum''. It belongs to the prymnesin family and has potent Hemolysis, hemolytic and Ichthyotoxin, i ...

. It is a flagellated

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

that is normally found suspended in the

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

. It was first identified in North America in 1985, but it is not known if it was introduced artificially (e.g., an invasive species) or missed in previous surveys. Toxin production mainly kills fish and appears to have little effect on cattle or humans. This distinguishes it from a

red tide A harmful algal bloom (HAB) (or excessive algae growth) is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins, mechanical damage to other organisms, or by other means. HABs are sometimes ...

, which is an

algal bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...

whose toxins lead to harmful effects in people. Although no harmful effects are known, it is recommended not to consume dead or dying fish exposed to a ''P. parvum'' bloom. ''P. parvum'' of Haptophyta is sometimes classified as a

golden alga The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer to a single species, '' Prymnesium parvum'', whi ...

or a golden brown alga, as is Chrysophyceae of

Heterokont Heterokonts are a group of protists (formally referred to as Heterokonta, Heterokontae or Heterokontophyta). The group is a major line of eukaryotes. Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which a ...

ophyta, but the taxonomy of algae is under complex revision, leading to contradictions in terms, especially in non-scholarly texts (such as those from state wildlife departments).

Biology

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''P. parvum'' grows in a salinity range of 0.5 - 30 psu (Practical Salinity Unit) with an optimum at 15 psu although strains collected in different places appear to have different salinity tolerances. A strain called LB 2797 (isolated from Colorado River in Texas) shows a biphasic growth pattern namely, maximum cell densities increased as salinity increased from 5 to 15 psu but decreased at higher levels in laboratory culture. The alga produces

dimethylsulfoniopropionate Dimethylsulfoniopropionate (DMSP), is an organosulfur compound with the formula (CH3)2S+CH2CH2COO−. This zwitterionic metabolite can be found in marine phytoplankton, seaweeds, and some species of terrestrial and aquatic vascular plants ...

(DMSP) and other unknown

polyol In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (). The term "polyol" can have slightly different meanings depending on whether it is used in food science or polymer chemistry. Polyols containing two, thr ...

s, likely as an adaptation to

osmoregulation Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration o ...

. The environment must be between and for ''P. parvum'' to live. Growth at a pH of as low as 5.8 has been observed, but cells typically prefer higher pH ranges. The organism prefers highly light environments, but growth can be inhibited by excessive light (

photoinhibition Photoinhibition is light-induced reduction in the photosynthetic capacity of a plant, alga, or cyanobacterium. Photosystem II (PSII) is more sensitive to light than the rest of the photosynthetic machinery, and most researchers define the term ...

). The organism is capable of

heterotrophic A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...

growth in the dark in the presence of

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

and grazes on bacteria, especially when

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

is limited. It has therefore been hypothesized that ''P. parvum'' satisfies its phosphate needs by consuming bacteria. ''P. parvum'' can use a wide range of

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

sources, including ammonium, nitrate,

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

s (which ones apparently depends on pH),

creatine Creatine ( or ) is an organic compound with the nominal formula (H2N)(HN)CN(CH3)CH2CO2H. It exists in various modifications (tautomers) in solution. Creatine is found in vertebrates where it facilitates recycling of adenosine triphosphate ( ...

, but is unable to use

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important ...

. New evidence has shown that the toxins produced by this alga are induced by physiological stresses, such as nitrogen and phosphorus depletion due to competition with the environment.

References

External links

*
Literature review of the microalga ''Prymnesium parvum'' and its associated toxicity
* * {{Taxonbar, from=Q7253251 Haptophytes High lipid content microalgae

Biology

See also

References

External links