Cyanidiophyceae

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Cyanidiophyceae
Cyanidium O5A.jpg
Cyanidium sp.
Scientific classification OOjs UI icon edit-ltr.svg
Clade: Archaeplastida
Division: Rhodophyta
Subdivision: Cyanidiophytina
Class: Cyanidiophyceae
T.Christensen
Families

Cyanidiophyceae is a class of unicellular red algae within subdivision Cyanidiophytina, and contain a single plastid, one to three mitochondria, a nucleus, a vacuole, and floridean starch. [1] Pyrenoids are absent. [2] Most are extremophiles inhabiting acid hot springs. They originated in extreme environments with high themperatures and low pH, which allowed them to occupy ecological niches without any competition. [3] While still found in extreme environments, they have also adapted to live along streams, in fissures in rock walls and in soil, but usually prefer relatively high temperatures. They have never been found in basic freshwater or seawater habitats. [4] The main photosynthetic pigment is C-phycocyanin. Reproduction is asexual by binary fission or formation of endospores. [5] The group, consisting of a single order (Cyanidiales), split off from the other red algae more than a billion years ago. Three families, four genera, and nine species are known, but the total number of species is probably higher. They are primarily photoautotrophic, but heterotrophic and mixotrophic growth also occurs. After the first massive gene loss in the common ancestor of all red algae, where ca. 25% of the genes were lost, a second gene loss occurred in the ancestor of Cyanidiophyceae, where additional 18% of the genes were lost. [6] Since then, some gene gains and minor gene losses have taken place independently in the Cyanidiaceae and Galdieriaceae, leading to genetic diversification between the two groups, with Galdieriaceae occupying more diverse and varied niches in extreme environments than Cyanidiaceae. [7]

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<span class="mw-page-title-main">Algae</span> Diverse group of photosynthetic eukaryotic organisms

Algae are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as Chlorella, Prototheca and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 metres (160 ft) in length. Most are aquatic and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds. In contrast, the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, Spirogyra and stoneworts. Algae that are carried by water are plankton, specifically phytoplankton.

<span class="mw-page-title-main">Chlorophyta</span> Phylum of green algae

Chlorophyta is a division of green algae informally called chlorophytes.

<span class="mw-page-title-main">Stramenopile</span> Clade of eukaryotes

The Stramenopiles, also called Heterokonts, are a clade of organisms distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, and in some they have been secondarily lost. Stramenopiles represent one of the three major clades in the SAR supergroup, along with Alveolata and Rhizaria.

<span class="mw-page-title-main">Plastid</span> Plant cell organelles that perform photosynthesis and store starch

A plastid is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. Plastids are considered to be intracellular endosymbiotic cyanobacteria.

<span class="mw-page-title-main">Glaucophyte</span> Division of algae

The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of unicellular algae found in freshwater and moist terrestrial environments, less common today than they were during the Proterozoic. The stated number of species in the group varies from about 14 to 26. Together with the red algae (Rhodophyta) and the green algae plus land plants, they form the Archaeplastida.

<span class="mw-page-title-main">Brown algae</span> Large group of multicellular algae, comprising the class Phaeophyceae

Brown algae are a large group of multicellular algae comprising the class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests that contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Some members of the class, such as kelps, are used by humans as food.

<span class="mw-page-title-main">Pyrenoid</span> Organelle found within the chloroplasts of algae and hornworts

Pyrenoids are sub-cellular micro-compartments found in chloroplasts of many algae, and in a single group of land plants, the hornworts. Pyrenoids are associated with the operation of a carbon-concentrating mechanism (CCM). Their main function is to act as centres of carbon dioxide (CO2) fixation, by generating and maintaining a CO2 rich environment around the photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Pyrenoids therefore seem to have a role analogous to that of carboxysomes in cyanobacteria.

<span class="mw-page-title-main">Florideophyceae</span> Class of algae

Florideophyceae is a class of exclusively multicellular red algae. They were once thought to be the only algae to bear pit connections, but these have since been found in the filamentous stage of the Bangiaceae. They were also thought only to exhibit apical growth, but there are genera known to grow by intercalary growth. Most, but not all, genera have three phases to the life cycle. In the subclass Nemaliophycidae there are three orders, Balbianiales, Batrachospermales, and Thoreales, which lives exclusively in freshwater.

<span class="mw-page-title-main">Archaeplastida</span> Clade of eukaryotes containing land plants and some algae

The Archaeplastida are a major group of eukaryotes, comprising the photoautotrophic red algae (Rhodophyta), green algae, land plants, and the minor group glaucophytes. It also includes the non-photosynthetic lineage Rhodelphidia, a predatorial (eukaryotrophic) flagellate that is sister to the Rhodophyta, and probably the microscopic picozoans. The Archaeplastida have chloroplasts that are surrounded by two membranes, suggesting that they were acquired directly through a single endosymbiosis event by phagocytosis of a cyanobacterium. All other groups which have chloroplasts, besides the amoeboid genus Paulinella, have chloroplasts surrounded by three or four membranes, suggesting they were acquired secondarily from red or green algae. Unlike red and green algae, glaucophytes have never been involved in secondary endosymbiosis events.

<i>Paulinella</i> Genus of single-celled organisms

Paulinella is a genus of at least eleven species including both freshwater and marine amoeboids. Like many members of euglyphids it is covered by rows of siliceous scales, and use filose pseudopods to crawl over the substrate of the benthic zone.

<span class="mw-page-title-main">Red algae</span> Division of plant life

Red algae, or Rhodophyta, make up one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 recognized species within over 900 genera amidst ongoing taxonomic revisions. The majority of species (6,793) are Florideophyceae, and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, no terrestrial species exist, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.

<i>Cyanophora paradoxa</i> Species of alga

Cyanophora paradoxa is a freshwater species of Glaucophyte that is used as a model organism. C. paradoxa has two cyanelles or chloroplasts where photosynthesis occurs. Cyanelles are unusual organelles in that they retain a rudimentary peptidoglycan wall. The cyanelle genome of C. paradoxa strain LB 555 was sequenced and published in 1995. The nuclear genome was also sequenced and published in 2012.

<i>Vaucheria litorea</i> Species of alga

Vaucheria litorea is a species of yellow-green algae (Xanthophyceae). It grows in a filamentous fashion. V. litorea is a common intertidal species of coastal brackish waters and salt marshes of the Northern Atlantic, along the coasts of Europe, North America and New Zealand. It is also found in the Eastern Pacific coasts of Washington state. It is found to be able to tolerate a large range of salinities, making it euryhaline.

<i>Polykrikos kofoidii</i> Species of single-celled organism

Polykrikos kofoidii is a species of phagotrophic marine pseudocolonial dinoflagellates that can capture and engulf other protist prey, including the toxic dinoflagellate, Alexandrium tamarense. P. kofoidii is of scientific interest due to its status as a predator of other dinoflagellates, a behavior that is significant in the control of algal blooms. It has a complex life cycle of both vegetative (asexual) and sexual reproduction complicated by its pseudocolonial structure.

<i>Galdieria sulphuraria</i> Extremophilic unicellular species of red alga

Galdieria sulphuraria is an extremophilic unicellular species of red algae. It is the type species of the genus Galdieria. It is known for its broad metabolic capacities, including photosynthesis and heterotrophic growth on over 50 different extracellular carbon sources. The members of the class Cyanidiophyceae are among the most acidophilic known photosynthetic organisms, and the growth conditions of G. sulphuraria – pH between 0 and 4, and temperatures up to 56 °C – are among the most extreme known for eukaryotes. Analysis of its genome suggests that its thermoacidophilic adaptations derive from horizontal gene transfer from archaea and bacteria, another rarity among eukaryotes.

A plastid is a membrane-bound organelle found in plants, algae and other eukaryotic organisms that contribute to the production of pigment molecules. Most plastids are photosynthetic, thus leading to color production and energy storage or production. There are many types of plastids in plants alone, but all plastids can be separated based on the number of times they have undergone endosymbiotic events. Currently there are three types of plastids; primary, secondary and tertiary. Endosymbiosis is reputed to have led to the evolution of eukaryotic organisms today, although the timeline is highly debated.

<span class="mw-page-title-main">Photoautotrophism</span> Organisms that use light and inorganic carbon to produce organic materials

Photoautotrophs are organisms that can utilize light energy from sunlight and elements from inorganic compounds to produce organic materials needed to sustain their own metabolism. Such biological activities are known as photosynthesis, and examples of such organisms include plants, algae and cyanobacteria.

Galdieria is a genus of red algae belonging to the order Galdieriales; family Galdieriaceae. It was created by an Italian botanist Aldo Merola in 1981 for the identification from the species of Cyanidium.

Crustaphytum is a genus of red alga first discovered in Taoyuan algal reefs by Taiwanese scientists. The epithet “crusta” refers to crustose thallus and “phytum” refers to plant. Belonging to the family Hapalidiaceae in the order Hapalidiales, Crustaphytum is one kind of crustose coralline algae.

<span class="mw-page-title-main">Halymeniales</span> Order of algae

Halymeniales is an order of red algae belonging to the class Florideophyceae and the subclass Rhodymeniophycidae.

References

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  3. Lee, Robert Edward (2018). Phycology. Cambridge University Press. ISBN   978-1-107-55565-5.
  4. Levine, Ira A.; Fleurence, Joël (2018). Microalgae in Health and Disease Prevention. Academic Press. ISBN   978-0-12-811406-3.
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