red algae

紅藻、紅藻類

関

red alga、Rhodophyta、rhodophyte

WordNet

1. lower plants; mostly marine and littoral eukaryotic algae (同)division Rhodophyta
2. of a color at the end of the color spectrum (next to orange); resembling the color of blood or cherries or tomatoes or rubies (同)reddish, ruddy, blood-red, carmine, cerise, cherry, cherry-red, crimson, ruby, ruby-red, scarlet
3. red color or pigment; the chromatic color resembling the hue of blood (同)redness
4. primitive chlorophyll-containing mainly aquatic eukaryotic organisms lacking true stems and roots and leaves (同)algae
5. the syllable naming the second (supertonic) note of any major scale in solmization (同)ray
6. a tributary of the Mississippi River that flows eastward from Texas along the southern boundary of Oklahoma and through Louisiana (同)Red River

PrepTutorEJDIC

1. 〈U〉〈C〉『赤,』『赤色;』赤い絵の具(染料) / 〈U〉赤い服 / 〈C〉《しばしば『R-』》《話》《時に軽べつして》アカ,共産主義者;過激論(主義)者 / 〈U〉《通例the ~》(会計の)赤字,負債 / 『赤い』,赤色の / (顔・目などが)赤くなった;血に染った / 赤い服を着た;赤毛の / 《しばしば『R-』》《話》《軽べつして》共産主義の;過激な
2. 藻(も);《複数形で》藻(そう)類(海草などの隠花植物)
3. レ(全音階の第2音)
4. 藻類

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/07/28 20:43:40」(JST)

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Red algae Temporal range: Mesoproterozoic–present Had'n Archean Proterozoic Pha.
A-D : Chondrus crispus Stackhouse, E-F : Mastocarpus stellatus J.Ag.
Scientific classification
Domain:	Eukaryota
(unranked):	Diaphoretickes
(unranked):	Archaeplastida
Division:	Rhodophyta Wettstein, 1922 Classification is currently disputed. See Taxonomy.

The red algae, or Rhodophyta (/roʊˈdɒfᵻtə/ roh-DOF-fit-tə or /ˌroʊdəˈfaɪtə/ ROH-də-FY-tə; from Ancient Greek: ῥόδον rhodon, "rose" and φυτόν phyton, "plant"), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and consist of mostly multicellular, marine algae, including many notable seaweeds. Approximately 5% of the red algae occur in freshwater environments.

The red algae form a distinct group characterized by having eukaryotic cells without flagella and centrioles, chloroplasts that lack external endoplasmic reticulum and contain unstacked (stoma) thylakoids, and use phycobiliproteins as accessory pigments, which give them their red color. Red algae store sugars as floridean starch, which is a type of starch that consists of highly branched amylopectin without amylose, as food reserves outside their plastids. Most red algae are also multicellular, macroscopic, marine, and reproduce sexually. The red algal life history is typically an alternation of generations that may have three generations rather than two.

Chloroplasts evolved following an endosymbiotic event between an ancestral, photosynthetic cyanobacterium and an early eukarytoic Phagotroph. This event (termed Primary endosymbiosis) resulted in the origin of the red and Green algae, and the Glaucophytes, which make up the oldest evolutionary lineages of photosynthetic eukaryotes. A secondary endosymbiosis event involving an ancestral red alga and a heterotrophic eukaryote resulted in the evolution and diversification of several other photosynthetic lineages.

The coralline algae, which secrete calcium carbonate and play a major role in building coral reefs, belong here. Red algae such as dulse (Palmaria palmata) and laver (nori/gim) are a traditional part of European and Asian cuisines and are used to make other products such as agar, carrageenans and other food additives.

Habitat

Unicellular members of the Cyanidiophyceae are thermoacidophiles and are found in sulphuric hot springs and other acidic environments. The remaining taxa are found in marine and freshwater environments. Most rhodophytes are marine with a worldwide distribution, and are often found at greater depths compared to other seaweeds because of dominance in certain pigments (i.e., Phycoerythrin) within their chloroplasts. Some marine species are found on sandy shores, while most others can be found attached to rocky substrata. Freshwater species account for 5% of red algal diversity, but they also have a worldwide distribution in various habitats; they generally prefer clean, high-flow streams with clear waters and rocky bottoms, but with some exceptions. A few freshwater species are found in black waters with sandy bottoms and even fewer are found in more lentic waters. Both marine and freshwater taxa are represented by free-living macroalgal forms and smaller endo/epiphytic/zoic forms, meaning they live in or on other algae, plants, and animals In addition, some marine species have adopted a parasitic lifestyle and may be found on closely or more distantly related red algal hosts

Taxonomy

Further information: Wikispecies:Rhodophyta

In the system of Adl et al. 2005, the red algae are classified in the Archaeplastida, along with the glaucophytes and green algae plus land plants (Viridiplantae or Chloroplastida). The authors use a hierarchical arrangement where the clade names do not signify rank; the class name Rhodophyceae is used for the red algae. No subdivisions are given; the authors say, "Traditional subgroups are artificial constructs, and no longer valid."

Many studies published since Adl et al. 2005 have provided evidence that is in agreement for monophyly in the Archaeplastida (including red algae). However, other studies have suggested Archaeplastida is paraphyletic. As of January 2011, the situation appears unresolved.

Below are other published taxonomies of the red algae using molecular and traditional alpha taxonomic data; however, the taxonomy of the red algae is still in a state of flux (with classification above the level of order having received little scientific attention for most of the 20th century).

• If one defines the kingdom Plantae to mean the Archaeplastida, the red algae will be part of that kingdom
• If Plantae are defined more narrowly, to be the Viridiplantae, then the red algae might be considered their own kingdom, or part of the kingdom Protista.

A major research initiative to reconstruct the Red Algal Tree of Life (RedToL) using phylogenetic and genomic approaches is funded by the National Science Foundation as part of the Assembling the Tree of Life Program.

Classification comparison

Classification system according to Saunders and Hommersand 2004	Classification system according to Hwan Su Yoon et al. 2006	Orders	Multicelluar?	Pit plugs?	Example
Subkingdom Rhodoplantae Phylum Cyanidiophyta Class Cyanidiophyceae Merola et al.	Phylum Rhodophyta Wettstein Subphylum Cyanidiophytina subphylum novus Class Cyanidiophyceae Merola et al.	Cyanidiales	No	No	Cyanidioschyzon merolae
Phylum Rhodophyta Wettstein Subphylum Rhodellophytina Class Rhodellophyceae Cavalier-Smith	Subphylum Rhodophytina subphylum novus Class Rhodellophyceae Cavalier-Smith	Rhodellales	No	No	Rhodella
Subphylum Metarhodophytina Class Compsopogonophyceae Saunders et Hommersand	Class Compsopogonophyceae Saunders et Hommersand	Compsopogonales, Rhodochaetales, Erythropeltidales	Yes	No	Compsopogon
	Class Stylonematophyceae classis nova	Rufusiales, Stylonematales	Yes	No	Stylonema
Subphylum Eurhodophytina Class Bangiophyceae Wettstein	Class Bangiophyceae Wettstein	Bangiales	Yes	Yes	Bangia, "Porphyra"
	Class Porphyridiophyceae classis nova	Porphyridiales	No	No	Porphyridium cruentum
Class Florideophyceae Cronquist Subclass Hildenbrandiophycidae	Class Florideophyceae Cronquist	Hildenbrandiales	Yes	Yes	Hildenbrandia
Subclass Nemaliophycidae		Batrachospermales, Balliales, Balbianiales, Nemaliales, Colaconematales, Acrochaetiales, Palmariales, Thoreales	Yes	Yes	Nemalion
		Rhodogorgonales, Corallinales	Yes	Yes	Corallina officinalis
Subclass Ahnfeltiophycidae		Ahnfeltiales, Pihiellales	Yes	Yes	Ahnfeltia
Subclass Rhodymeniophycidae		Bonnemaisoniales, Gigartinales, Gelidiales, Gracilariales, Halymeniales, Rhodymeniales, Nemastomatales, Plocamiales, Ceramiales	Yes	Yes	Gelidium

Some sources (such as Lee) place all red algae into the class "Rhodophyceae". (Lee's organization is not a comprehensive classification, but a selection of orders considered common or important.)

A subphylum - Proteorhodophytina - has been proposed to encompass the existing classes Compsopogonophyceae, Porphyridiophyceae, Rhodellophyceae and Stylonematophyceae. This proposal was made on the basis of the analysis of the plastid genomes.

See also: Eukaryote § Phylogeny

Species of red algae

Over 7,000 species are currently described for the red algae, but the taxonomy is in constant flux with new species described each year. The vast majority of these are marine with about 200 that live only in fresh water.

Some examples of species and genera of red algae are:

• Cyanidioschyzon merolae, a primitive red alga
• Atractophora hypnoides
• Gelidiella calcicola
• Lemanea, a freshwater genus
• Palmaria palmata, dulse
• Schmitzia hiscockiana
• Chondrus crispus, Irish moss
• Mastocarpus stellatus
• Vanvoorstia bennettiana, became extinct in the early 20th century
• Acrochaetium efflorescens
• Audouinella, with freshwater as well as marine species
• Polysiphonia ceramiaeformis, banded siphon weed

Morphology

Red algae have double cell walls. The outer layers contain the polysaccharides agarose and agaropectin that can be extracted from the cell walls by boiling as agar. The internal walls are mostly cellulose.

Pit connections and pit plugs

Main article: Pit connection

Pit connections

Pit connections and pit plugs are unique and distinctive features of red algae that form during the process of cytokinesis following mitosis. In red algae, cytokinesis is incomplete. Typically, a small pore is left in the middle of the newly formed partition. The pit connection is formed where the daughter cells remain in contact.

Shortly after the pit connection is formed, cytoplasmic continuity is blocked by the generation of a pit plug, which is deposited in the wall gap that connects the cells.

Connections between cells having a common parent cell are called primary pit connections. Because apical growth is the norm in red algae, most cells have two primary pit connections, one to each adjacent cell.

Connections that exist between cells not sharing a common parent cell are labeled secondary pit connections. These connections are formed when an unequal cell division produced a nucleated daughter cell that then fuses to an adjacent cell. Patterns of secondary pit connections can be seen in the order Ceramiales.

Pit plugs

After a pit connection is formed, tubular membranes appear. A granular protein, called the plug core, then forms around the membranes. The tubular membranes eventually disappear. While some orders of red algae simply have a plug core, others have an associated membrane at each side of the protein mass, called cap membranes. The pit plug continues to exist between the cells until one of the cells dies. When this happens, the living cell produces a layer of wall material that seals off the plug.

Function

The pit connections have been suggested to function as structural reinforcement, or as avenues for cell-to-cell communication and transport in red algae, however little data supports this hypothesis.

Reproduction

The reproductive cycle of red algae may be triggered by factors such as day length.

Fertilization

Red algae lack motile sperm. Hence, they rely on water currents to transport their gametes to the female organs – although their sperm are capable of "gliding" to a carpogonium's trichogyne.

The trichogyne will continue to grow until it encounters a spermatium; once it has been fertilized, the cell wall at its base progressively thickens, separating it from the rest of the carpogonium at its base.

Upon their collision, the walls of the spermatium and carpogonium dissolve. The male nucleus divides and moves into the carpogonium; one half of the nucleus merges with the carpogonium's nucleus.

The polyamine spermine is produced, which triggers carpospore production.

Spermatangia may have long, delicate appendages, which increase their chances of "hooking up".

Life cycle

They display alternation of generations; in addition to gametophyte generation, many have two sporophyte generations, the carposporophyte-producing carpospores, which germinate into a tetrasporophyte – this produces spore tetrads, which dissociate and germinate into gametophytes. The gametophyte is typically (but not always) identical to the tetrasporophyte.

Carpospores may also germinate directly into thalloid gametophytes, or the carposporophytes may produce a tetraspore without going through a (free-living) tetrasporophyte phase. Tetrasporangia may be arranged in a row (zonate), in a cross (cruciate), or in a tetrad.

The carposporophyte may be enclosed within the gametophyte, which may cover it with branches to form a cystocarp.

These case studies may be helpful to understand some of the life histories algae may display:

In a simple case, such as Rhodochorton investiens:

In the Carposporophyte: a spermatium merges with a trichogyne (a long hair on the female sexual organ), which then divides to form carposporangia – which produce carpospores.

Carpospores germinate into gametophytes, which produce sporophytes. Both of these are very similar; they produce monospores from monosporangia "just below a cross wall in a filament" and their spores are "liberated through apex of sporangial cell."

The spores of a sporophyte produce either tetrasporophytes. Monospores produced by this phase germinate immediately, with no resting phase, to form an identical copy of parent. Tetrasporophytes may also produce a carpospore, which germinates to form another tetrasporophyte.

The gametophyte may replicate using monospores, but produces sperm in spermatangia, and "eggs"(?) in carpogonium.

A rather different example is Porphyra gardneri:

In its diploid phase, a carpospore can germinate to form a filamentous "conchocelis stage", which can also self-replicate using monospores. The conchocelis stage eventually produces conchosporangia. The resulting conchospore germinates to form a tiny prothallus with rhizoids, which develops to a cm-scale leafy thallus. This too can reproduce via monospores, which are produced inside the thallus itself. They can also reproduce via spermatia, produced internally, which are released to meet a prospective carpogonium in its conceptacle.

Chemistry

Algal group	δ13C range
HCO3-using red algae	−22.5‰ to −9.6‰
CO2-using red algae	−34.5‰ to −29.9‰
Brown algae	−20.8‰ to −10.5‰
Green algae	−20.3‰ to −8.8‰

The δ¹³C values of red algae reflect their lifestyles. The largest difference results from their photosynthetic metabolic pathway: algae that use HCO₃ as a carbon source have less negative δ¹³C values than those that only use CO₂. An additional difference of about 1.71‰ separates groups intertidal from those below the lowest tide line, which are never exposed to atmospheric carbon. The latter group uses the more ¹³C-negative CO₂ dissolved in sea water, whereas those with access to atmospheric carbon reflect the more positive signature of this reserve.

Red algae are red due to phycoerythrin. They contain the sulfated polysaccharide carrageenan in the amorphous sections of their cell walls, although red algae from the genus Porphyra contain porphyran. They also produce a specific type of tannin called phlorotannins, but in lower amount than brown algae do.

Genomes of red algae

Complete genome sequences are only available for 5 species of red algae, including 4 published in 2013.

• Cyanidioschyzon merolae, Cyanidiophyceae
• Galdieria sulphuraria, Cyanidiophyceae
• Pyropia yezoensis, Bangiophyceae
• Chondrus crispus, Florideophyceae
• Porphyridium purpureum, Porphyridiophyceae

Evolution

Fossil record

One of the oldest fossils identified as a red alga is also the oldest fossil eukaryote that belongs to a specific modern taxon. Bangiomorpha pubescens, a multicellular fossil from arctic Canada, strongly resembles the modern red alga Bangia despite occurring in rocks dating to 1.2 billion years ago.

Two kinds of fossils resembling red algae were found sometime between 2006 and 2011 in well-preserved sedimentary rocks in Chitrakoot, central India. The presumed red algae lie embedded in fossil mats of cyanobacteria, called stromatolites, in 1.6 billion-year-old Indian phosphorite — making them the oldest plant-like fossils ever found by about 400 million years.

Red algae are important builders of limestone reefs. The earliest such coralline algae, the solenopores, are known from the Cambrian period. Other algae of different origins filled a similar role in the late Paleozoic, and in more recent reefs.

Calcite crusts that have been interpreted as the remains of coralline red algae, date to the terminal Proterozoic. Thallophytes resembling coralline red algae are known from the late Proterozoic Doushantuo formation.

Relationship to other algae

Chromista and Alveolata algae (e.g., chrysophytes, diatoms, phaeophytes, dinophytes) seem to have evolved from bikonts that have acquired red algae as endosymbionts. According to this theory, over time these endosymbiont red algae have evolved to become chloroplasts. This part of endosymbiotic theory is supported by various structural and genetic similarities.

Human consumption

Several species are important food crops, in particular members of the genus Porphyra, variously known as nori (Japan), gim (Korea), or laver (Britain). Dulse (Palmaria palmata) is another important British species. These rhodophyte foods are high in vitamins and protein and are easily grown; for example, nori cultivation in Japan goes back more than three centuries.

In East and Southeast Asia, agar is most commonly produced from Gelidium amansii.

Gallery

• Cyanidium sp. (Cyanidiophyceae)

• Porphyra sp., haploid and diploid (Bangiophyceae)

• Chondrus crispus (Florideophyceae: Gigartinales)

• Gracilaria sp. (Florideophyceae: Gracilariales)

• Corallina officinalis sp. (Florideophyceae: Corallinales)

• Laurencia sp. (Florideophyceae: Ceramiales)

• Some red algae are iridescent when not covered with water

See also

• Brown algae
• Green algae
• History of phycology

External links

• AlgaeBase: Rhodophyta
• Seaweed Site: Rhodophyta
• Tree of Life: Rhodophyta
• Monterey Bay Flora

UpToDate Contents

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• 1. シガテラ中毒ciguatera fish poisoning [show details]
  …and snails that are contaminated with dinoflagellates of the genus Alexandrium. These algae are also associated with red tides in temperate waters. Physical findings occur within hours of ingestion and include …
• 2. 脱力がみられる小児の病因および評価etiology and evaluation of the child with weakness [show details]
  …occurs in patients who eat shellfish harvested from contaminated beds or during times of algae blooms known as red tides. Trichinellosis occurs in patients who consume undercooked pork or other contaminated …
• 3. 赤血球水分量の制御control of red blood cell hydration [show details]
  …occurring when red cell ion transport is impaired The transport systems involved in regulating the volume and composition of red cells, and which affect the cation, anion, and water content of the red cell, will …
• 4. 赤血球細胞の生存：正常値と測定値red blood cell survival normal values and measurement [show details]
  …antibodies, when membrane bound, lead to partial complement activation on the red cell surface, which may be associated with decreased red cell deformability . These, in turn, are recognized by complement receptors …
• 5. 新生児における赤血球輸血red blood cell transfusions in the newborn [show details]
  …without signs or oxygen requirements who are actively producing new red cells and have an elevated reticulocyte count likely do not require a red cell transfusion. Other centers and societies have transfusion …

English Journal

• Algal sulfated carrageenan inhibits proliferation of MDA-MB-231 cells via apoptosis regulatory genes.

• Murad H1, Ghannam A1, Al-Ktaifani M2, Abbas A3, Hawat M1.
• Molecular medicine reports.Mol Med Rep.2015 Mar;11(3):2153-8. doi: 10.3892/mmr.2014.2915. Epub 2014 Nov 10.
• Marine algae are prolific sources of sulfated polysaccharides, which may explain the low incidence of certain cancers in countries that traditionally consume marine food. Breast cancer is one of the most common types of non‑skin cancer in females. In this study, extracted sulfated carrageenan (ESC
• PMID 25384757

• Evaluation of the utility of six measures for algal (Microcystis aeruginosa, Planktothrix agardhii and Pseudokirchneriella subcapitata) viability.

• Calomeni AJ1, Rodgers JH Jr2.
• Ecotoxicology and environmental safety.Ecotoxicol Environ Saf.2015 Jan;111:192-8. doi: 10.1016/j.ecoenv.2014.09.033. Epub 2014 Oct 28.
• Standard algal toxicity tests are used to discern responses of algae to a variety of exposures including pesticides, personal care products and complex mixtures such as runoff and effluents. There are concerns regarding the accuracy, precision and utility of algal viability measures used as endpoint
• PMID 25450933

• Toxic assessment of the leachates of paddy soils and river sediments from e-waste dismantling sites to microalga, Pseudokirchneriella subcapitata.

• Nie X1, Fan C2, Wang Z2, Su T2, Liu X3, An T4.
• Ecotoxicology and environmental safety.Ecotoxicol Environ Saf.2015 Jan;111:168-76. doi: 10.1016/j.ecoenv.2014.10.012. Epub 2014 Oct 28.
• The potential adverse effects of e-waste recycling activity on environment are getting increasing concern. In this work, a model alga, Pseudokirchneriella subcapitata, was employed to assess the toxic effects of the leachates of paddy soils and river sediments collected from e-waste dismantling site
• PMID 25450930

Japanese Journal

• Effect of irradiance and temperature on the photosynthesis of a cultivated red alga, Pyropia tenera (= Porphyra tenera), at the southern limit of distribution in Japan

• Watanabe Yuki,Nishihara Gregory N.,Tokunaga Shigemitsu [他]
• Phycological research 62(3), 187-196, 2014-07
• NAID 40020140295

• Phenology, irradiance and temperature characteristics of a freshwater red alga, Nemalionopsis tortuosa (Thoreales), from Kagoshima, southern Japan

• Fujimoto Midori,Nitta Koji,Nishihara Gregory N. [他]
• Phycological research 62(2), 77-85, 2014-04
• NAID 40020051268

• Phenology and Morphology of the Two Freshwater Red Algae (Rhodophyta) in the Imperial Palace, Tokyo (皇居の生物相(2)植物相)

• 北山 太樹
• 国立科学博物館専報 (49), 89-96, 2014-03
• NAID 40020057039

Related Links

• Red algae - Wikipedia, the free encyclopedia

The red algae, or Rhodophyta are one of the oldest groups of eukaryotic algae, and also one of the largest, with about 5000–6000 species of mostly multicellular, marine algae, including many notable seaweeds. Other references indicate as ...

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リンク元	「紅藻類」「Rhodophyta」「rhodophyte」「紅藻」「red alga」
関連記事	「red」「alga」

「紅藻類」

　　[★]

英

red alga、red algae、rhodophyte、Rhodophyta

関

紅色植物、紅藻、紅藻植物、紅藻植物門

「Rhodophyta」

　　[★]

• 紅藻類、紅藻植物、紅色植物、紅藻植物門

関

red alga、red algae、rhodophyte

　

「rhodophyte」

　　[★]

紅藻、紅藻類、紅色植物

関

red alga、red algae、Rhodophyta

「紅藻」

　　[★]

英

red alga、red algae、rhodophyte

関

紅色植物、紅藻類

「red alga」

　　[★]

紅藻、紅藻類

関

red algae、Rhodophyta、rhodophyte

「red」

　　[★]

• adj.

• 赤色の、赤、赤い

関

erythro

　 　 　

「alga」

　　[★]

藻類

関

algae、algal