Peranemid

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Peranemid
Peranema (Flagellat) - 400x (8492749542).jpg
Light microscopy photograph of a Peranema species
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Phylum: Euglenozoa
Class: Euglenida
Clade: Spirocuta
Order: Peranemida
Cavalier-Smith, 1993
Family: Peranemidae
Bütschli, 1884
Genera

The peranemids are a group of phagotrophic flagellates, single-celled eukaryotes or protists. They belong to the Euglenida, a diverse lineage of flagellates that contains the closely related euglenophyte algae. Like these algae, peranemids have flexible cells capable of deformation or metaboly, and have one or two flagella in the anterior region of the cell. They are classified as family Peranemidae (ICZN) or Peranemataceae (ICBN) within the monotypic order Peranemida (ICZN) or Peranematales (ICBN).

Description

Peranemids are unicellular eukaryotes or protists. They are flagellates, with one or two flagella for locomotion. The flagella are located in the anterior end of the cell, and are used in a gliding motion in contact with the substrate to propel the cell forward. [1] In addition, like some other euglenids, their cells exhibit a certain movement known as metaboly or 'euglenid motion' characterized by extreme flexibility and malleability. [2]

Evolution

Peranemids are a group of Euglenida, a diverse lineage of flagellates containing the closely related euglenophyte algae. In particular, both peranemids and euglenophytes belong to the Spirocuta clade, which contains all flexible euglenids capable of elastic movement or metaboly. This quality is due to the high number of proteinaceous strips that are present underneath their cell membrane, in comparison to more basal euglenids such as ploeotids which are completely rigid. [2]

In molecular phylogenetic analyses, they were solved as a paraphyletic group encompassing various independent clades scattered across the Spirocuta clade. [2] More recent multigene analyses resolve peranemids as the monophyletic sister group of the photosynthetic Euglenophyceae. [3] [4] However, these analyses are incomplete, since there is a lack of molecular data for the peranemid genus Teloprocta , and other genera such as Urceolus and Heteronema are not fully represented. For these reasons, the monophyly of peranemids has not been completely tested. [3] These findings are summarized in the following cladogram:

Euglenida

Classification

Currently, five genera are accepted within the peranemids: [2]

Related Research Articles

<span class="mw-page-title-main">Flagellate</span> Group of protists with at least one whip-like appendage

A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word flagellate also describes a particular construction characteristic of many prokaryotes and eukaryotes and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagella. However, the term "flagellate" is included in other terms which are more formally characterized.

<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.

<i>Euglena</i> Genus of unicellular flagellate eukaryotes

Euglena is a genus of single cell flagellate eukaryotes. It is the best known and most widely studied member of the class Euglenoidea, a diverse group containing some 54 genera and at least 200 species. Species of Euglena are found in fresh water and salt water. They are often abundant in quiet inland waters where they may bloom in numbers sufficient to color the surface of ponds and ditches green (E. viridis) or red (E. sanguinea).

<span class="mw-page-title-main">Euglenid</span> Class of protozoans

Euglenids are one of the best-known groups of flagellates, which are excavate eukaryotes of the phylum Euglenophyta and their cell structure is typical of that group. They are commonly found in freshwater, especially when it is rich in organic materials, with a few marine and endosymbiotic members. Many euglenids feed by phagocytosis, or strictly by diffusion. A monophyletic group consisting of the mixotrophic Rapaza viridis and the two groups Eutreptiales and Euglenales have chloroplasts and produce their own food through photosynthesis. This group is known to contain the carbohydrate paramylon.

<span class="mw-page-title-main">Excavata</span> Supergroup of unicellular organisms belonging to the domain Eukaryota

Excavata is an extensive and diverse but paraphyletic group of unicellular Eukaryota. The group was first suggested by Simpson and Patterson in 1999 and the name latinized and assigned a rank by Thomas Cavalier-Smith in 2002. It contains a variety of free-living and symbiotic protists, and includes some important parasites of humans such as Giardia and Trichomonas. Excavates were formerly considered to be included in the now obsolete Protista kingdom. They were distinguished from other lineages based on electron-microscopic information about how the cells are arranged. They are considered to be a basal flagellate lineage.

Cryptomonas is the name-giving genus of the Cryptomonads established by German biologist Christian Gottfried Ehrenberg in 1831. The algae are common in freshwater habitats and brackish water worldwide and often form blooms in greater depths of lakes. The cells are usually brownish or greenish in color and are characteristic of having a slit-like furrow at the anterior. They are not known to produce any toxins. They are used to feed small zooplankton, which is the food source for small fish in fish farms. Many species of Cryptomonas can only be identified by DNA sequencing. Cryptomonas can be found in several marine ecosystems in Australia and South Korea.

<span class="mw-page-title-main">Telonemia</span> Phylum of single-celled organisms

Telonemia is a phylum of microscopic eukaryotes commonly known as telonemids. They are unicellular free-living flagellates with a unique combination of cell structures, including a highly complex cytoskeleton unseen in other eukaryotes.

<span class="mw-page-title-main">Euglenales</span> Order of flagellate eukaryotes

Euglenales is an order of flagellates in the phylum Euglenozoa. The family includes the most well-known euglenoid genus, Euglena, as well as other common genera like Phacus and Lepocinclis.

<span class="mw-page-title-main">Euglenaceae</span> Family of flagellate eukaryotes

Euglenaceae is a family of flagellates in the phylum Euglenozoa. The family includes the most well-known euglenoid genus, Euglena.

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

Ochrophytes, also known as heterokontophytes or stramenochromes, are a group of algae. They are the photosynthetic stramenopiles, a group of eukaryotes, organisms with a cell nucleus, characterized by the presence of two unequal flagella, one of which has tripartite hairs called mastigonemes. In particular, they are characterized by photosynthetic organelles or plastids enclosed by four membranes, with membrane-bound compartments called thylakoids organized in piles of three, chlorophyll a and c as their photosynthetic pigments, and additional pigments such as β-carotene and xanthophylls. Ochrophytes are one of the most diverse lineages of eukaryotes, containing ecologically important algae such as brown algae and diatoms. They are classified either as phylum Ochrophyta or Heterokontophyta, or as subphylum Ochrophytina within phylum Gyrista. Their plastids are of red algal origin.

<span class="mw-page-title-main">Bigyra</span> Phylum of single-celled organisms

Bigyra is a phylum of microscopic eukaryotes that are found at the base of the Stramenopiles clade. It includes three well-known heterotrophic groups Bicosoecida, Opalinata and Labyrinthulomycetes, as well as several small clades initially discovered through environmental DNA samples: Nanomonadea, Placididea, Opalomonadea and Eogyrea. The classification of Bigyra has changed several times since its origin, and its monophyly remains unresolved.

<span class="mw-page-title-main">Holozoa</span> Clade containing animals and some protists

Holozoa is a clade of organisms that includes animals and their closest single-celled relatives, but excludes fungi and all other organisms. Together they amount to more than 1.5 million species of purely heterotrophic organisms, including around 300 unicellular species. It consists of various subgroups, namely Metazoa and the protists Choanoflagellata, Filasterea, Pluriformea and Ichthyosporea. Along with fungi and some other groups, Holozoa is part of the Opisthokonta, a supergroup of eukaryotes. Choanofila was previously used as the name for a group similar in composition to Holozoa, but its usage is discouraged now because it excludes animals and is therefore paraphyletic.

Michael Melkonian is a German botanist and professor of botany at the University of Cologne.

Heteronema is a genus of phagotrophic, flagellated euglenoids that are most widely distributed in fresh water environments. This genus consists of two very distinguishable morphogroups that are phylogenetically closely related. These morphogroups are deciphered based on shape, locomotion and other ultrastructural traits. However, this genus does impose taxonomic problems due to the varying historical descriptions of Heteronema species and its similarity to the genus Paranema. The species H. exaratum, was the first heteronemid with a skidding motion to be sequenced, which led to the discovery that it was not closely related to H. scaphrum, contrary to what was previously assumed, but instead to a sister group of primary osmotrophs. This suggests that skidding heteronemids can also be distinguished phylogenetically, being more closely related to Anisoma, Dinema and Aphageae, than to other species within Heteronema.

<span class="mw-page-title-main">Ultrastructural identity</span>

Ultrastructural identity is a concept in biology. It asserts that evolutionary lineages of eukaryotes in general and protists in particular can be distinguished by complements and arrangements of cellular organelles. These ultrastructural components can be visualized by electron microscopy.

<span class="mw-page-title-main">Cortical alveolum</span> Cellular organelle found in protists

The cortical alveolum is a cellular organelle consisting of a vesicle located under the cytoplasmic membrane, to which they give support. The term "corticate" comes from an evolutionary hypothesis about the common origin of kingdoms Plantae and Chromista, because both kingdoms have cortical alveoli in at least one phylum. At least three protist lineages exhibit these structures: Telonemia, Alveolata and Glaucophyta.

<i>Urceolus</i> Genus of flagellates

Urceolus is a genus of heterotrophic flagellates belonging to the Euglenozoa, a phylum of single-celled eukaryotes or protists. Described by Russian biologist Konstantin Mereschkowsky in 1877, its type species is Urceolus alenizini. Species of this genus are characterized by deformable flask-shaped cells that exhibit at least one flagellum that is active at the tip, arising from a neck-like structure that also hosts the feeding apparatus. They are found in a variety of water body sediments across the globe. According to evolutionary studies, Urceolus belongs to a group of Euglenozoa known as peranemids, closely related to the euglenophyte algae.

<span class="mw-page-title-main">Chrompodellid</span> Clade of alveolates

Chrompodellids are a clade of single-celled protists belonging to the Alveolata supergroup. It comprises two different polyphyletic groups of flagellates: the colpodellids, phagotrophic predators, and the chromerids, photosynthetic algae that live as symbionts of corals. These groups were independently discovered and described, but molecular phylogenetic analyses demonstrated that they are intermingled in a clade that is the closest relative to Apicomplexa, and they became collectively known as chrompodellids. Due to the history of their research, they are variously known in biological classification as Chromerida or Colpodellida (ICZN)/Colpodellales (ICN).

<i>Urceolus alenizini</i> Species of flagellate

Urceolus alenizini is a species of flagellates. It was described by Konstantin Mereschkowsky in 1877 as the type species of the genus Urceolus. It is a rare species only recorded by its author once in the White Sea, in northern Russia. It is distinguished by other members of the genus by the lack of spiral stripes in its cell surface.

<i>Ploeotia</i> Genus of flagellates

Ploeotia is a genus of heterotrophic flagellates belonging to the Euglenida, a diverse group of flagellated protists in the phylum Euglenozoa. Species of Ploeotia are composed of rigid cells exhibiting two flagella. The genus was described by Félix Dujardin in 1841.

References

  1. Gordon Lax; Alastair G. B. Simpson (16 August 2020). "The Molecular Diversity of Phagotrophic Euglenids Examined Using Single-cell Methods". Protist . 171 (5): 125757. doi:10.1016/J.PROTIS.2020.125757. ISSN   1434-4610. PMID   33126020. Wikidata   Q101127864.
  2. 1 2 3 4 Alexei Y. Kostygov; Anna Karnkowska; Jan Votýpka; Daria Tashyreva; Kacper Maciszewski; Vyacheslav Yurchenko; Julius Lukeš (10 March 2021). "Euglenozoa: taxonomy, diversity andecology, symbioses and viruses". Open Biology . 11: 200407. doi:10.1098/RSOB.200407. ISSN   2046-2441. PMC   8061765 . PMID   33715388. Wikidata   Q125548575.
  3. 1 2 G. Lax; M. Kolisko; Y. Eglit; et al. (June 2021). "Multigene phylogenetics of euglenids based on single-cell transcriptomics of diverse phagotrophs". Molecular Phylogenetics and Evolution . 159: 107088. doi:10.1016/J.YMPEV.2021.107088. ISSN   1055-7903. Wikidata   Q110667805.
  4. Gordon Lax; Anna Cho; Patrick J. Keeling (30 March 2023). "Phylogenomics of novel ploeotid taxa contribute to the backbone of the euglenid tree". Journal of Eukaryotic Microbiology . 70 (4). doi:10.1111/JEU.12973. ISSN   1066-5234. Wikidata   Q123348233.
  5. W.J. Lee; R. Blackmore; D.J. Patterson (1999). "Australian records of two lesser known genera of heterotrophic euglenids – Chasmostoma Massart, 1920 and Jenningsia Schaeffer, 1918". Protistology. 1 (1): 10–16.