Dileptus margaritifer

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Dileptus margaritifer
ProtozoaDileptusanser.png
Dileptus margaritifer
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Alveolata
Phylum: Ciliophora
Class: Litostomatea
Order: Dileptida
Family: Dileptidae
Genus: Dileptus
Species:
D. margaritifer
Binomial name
Dileptus margaritifer
(Ehrenberg, 1834) Dujardin, 1841

Dileptus margaritifer is a species of ciliates in the family Dileptidae. It is common in freshwater streams, lakes and ponds, as well as mosses and soil. The species has been found on every continent except Antarctica. [1]

Contents

Because of a taxonomic error by one researcher in the 19th century, specimens of Dileptus margaritifer have been misidentified in most studies as Dileptus anser (Müller, 1773). [1]

Morphology

Dileptus margaritifer has a slender body, usually about 450 μm in length and very flexible, narrowing at the posterior into a small, sharp tail. At its front, it has a broad and tapering proboscis, reminiscent of an elephant's trunk in its shape and flexibility, but with a flattened rather than round cross-section. The proboscis is 1/3 to 1/2 of the total body length. The cellular mouth (cytostome) sits at the base of the proboscis within a protuberance called the "oral bulge." The cell has a row of 4-20 contractile vacuoles along the dorsal surface, and at least 200 macronuclei scattered in the cytoplasm, with several spherical micronuclei distributed among them.

Feeding habits

Dileptus margaritifer feeds upon other unicellular organisms, using toxic extrusomes embedded in its proboscis to strike and stun its prey. The tip of the proboscis sometimes adheres to other objects, and can become detached. Most of the proboscis may be lost in this way during a feeding period, but is quickly regenerated. Captured prey is ingested through an oral aperture (cytostome) at the base of the proboscis. In one study, it was found that Dileptus margaritifer fed almost exclusively in the early morning, between 4am and 9am. [2] [3]

Reproduction

Like most ciliates, Dileptus margaritifer reproduces asexually, by transverse division of the cell (fission). Division may be preceded by conjugation, a sexual phenomenon in which two ciliates of compatible mating types exchange genetic material by reciprocal transfer of haploid gametes, derived by meiosis from each cell's micronuclei. The species is known to have three distinct mating types (sexes), conventionally designated I, II, and III. Individuals may cycle through several mating types in the course of their lives. However the final and (usually) stable type is genetically determined by a single genetic locus mat with three alleles, one for each type, with type I being dominant over type II, and II over III. [4]

History and classification

Dileptus margaritifer has had a confusing nomenclatural history. The species was originally described by C. G. Ehrenberg, under the name Amphileptus margaritifer. Eight years later, Félix Dujardin created the new genus Dileptus and placed A. margaritifer within it. [5] In the same work, he misidentified a specimen of Dileptus margaritifer, and published a description and illustration of it under the name Dileptus anser. The error was repeated by later taxonomists, including the influential Alfred Kahl. As a result, Dileptus margaritifer has been widely cultured and studied under the name Dileptus anser. [1]

Related Research Articles

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

The Litostomatea are a class of ciliates. The group consists of three subclasses: Haptoria, Trichostomatia and Rhynchostomatia. Haptoria includes mostly carnivorous forms such as Didinium, a species of which preys primarily on the ciliate Paramecium. Trichostomatia (trichostomes) are mostly endosymbionts in the digestive tracts of vertebrates. These include the species Balantidium coli, which is the only ciliate parasitic in humans. The group Rhynchostomatia includes two free-living orders previously included among the Haptoria, but now known to be genetically distinct from them, the Dileptida and the Tracheliida.

<i>Paramecium</i> Genus of unicellular ciliates, commonly studied as a representative of the ciliate group

Paramecium is a genus of eukaryotic, unicellular ciliates, commonly studied as a model organism of the ciliate group. Paramecium are widespread in freshwater, brackish, and marine environments and are often abundant in stagnant basins and ponds. Because some species are readily cultivated and easily induced to conjugate and divide, they have been widely used in classrooms and laboratories to study biological processes. The usefulness of Paramecium as a model organism has caused one ciliate researcher to characterize it as the "white rat" of the phylum Ciliophora.

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

Blepharisma is a genus of unicellular ciliate protists found in fresh and salt water. The group includes about 40 accepted species, and many sub-varieties and strains. While species vary considerably in size and shape, most are easily identified by their red or pinkish color, which is caused by granules of the pigment blepharismin.

<i>Stentor</i> (ciliate) Genus of single-celled organisms

Stentor, sometimes called trumpet animalcules, are a genus of filter-feeding, heterotrophic ciliates, representative of the heterotrichs. They are usually horn-shaped, and reach lengths of two millimeters; as such, they are among the largest known extant unicellular organisms. They reproduce asexually through binary fission.

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

Didinium is a genus of unicellular ciliates with at least ten accepted species. All are free-living carnivores. Most are found in fresh and brackish water, but three marine species are known. Their diet consists largely of Paramecium, although they will also attack and consume other ciliates. Some species, such as D. gargantua, also feeds on non-ciliate protists, including dinoflagellates, cryptomonads, and green algae.

<i>Spirostomum</i> Genus of ciliated protists

Spirostomum is a genus of ciliated protists in the class Heterotrichea. It is known for being very contractile. Having been first identified by Christian Gottfried Ehrenberg in 1834, further research has identified eight additional true morphospecies. This bacterivore genus mainly lives in the sediment deposits at the bottom of various aquatic habitats, and members possess rquA genes that could be responsible for their ability to survive in these hypoxic and anoxic environments. They are identifiable by their relatively large tubular/flat vermiform bodies. Their life cycle consists of a growth stage, in which they mature, and asexual and sexual reproduction stages. Some species are model organisms for studies on human pathogenic bacteria, while others are sensitive and accurate bioindicators for toxic substances.

<i>Paramecium caudatum</i> Species of single-celled organism

Paramecium caudatum is a species of unicellular protist in the phylum Ciliophora. They can reach 0.33 mm in length and are covered with minute hair-like organelles called cilia. The cilia are used in locomotion and feeding. The species is very common, and widespread in marine, brackish and freshwater environments.

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

Nassula is a genus of unicellular ciliates, belonging to the class Nassophorea. Like other members of the class, Nassula possesses a basket-like feeding apparatus made up of cytopharyngeal rods (nematodesmata), which are themselves composed of closely packed microtubules. Nassula use this structure to ingest filamentous cyanobacteria, drawing individual strands of blue-green algae through the cytopharynx and into the body of the cell, where they are digested. As the algae are broken down, they can take on a variety of bright colours, which give Nassula a distinctive, variegated appearance under the microscope.

Karyorelictea is a class of ciliates in the subphylum Postciliodesmatophora. Most species are members of the microbenthos community, that is, microscopic organisms found in the marine interstitial habitat, though one genus, Loxodes, is found in freshwater.

<span class="mw-page-title-main">Ciliate</span> Taxon of protozoans with hair-like organelles called cilia

The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group and are variously used in swimming, crawling, attachment, feeding, and sensation.

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

Frontonia is a genus of free-living unicellular ciliate protists, belonging to the order Peniculida. As Peniculids, the Frontonia are closely related to members of the genus Paramecium. However, whereas Paramecia are mainly bacterivores, Frontonia are capable of ingesting large prey such as diatoms, filamentous algae, testate amoebas, and even, in some circumstances, members of their own species. In bacteria-rich saprobic conditions, Frontonia leucas can live as a facultative bacterivore.

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

Climacostomum is a genus of unicellular ciliates, belonging to the class Heterotrichea.

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

Dileptus is a genus of unicellular ciliates in the class Litostomatea. Species of Dileptus occur in fresh and salt water, as well as mosses and soils. Most are aggressive predators equipped with long, mobile proboscides lined with toxic extrusomes, with which they stun smaller organisms before consuming them. Thirteen species and subspecies of Dileptus are currently recognized.

<i>Sterkiella histriomuscorum</i> Species of single-celled organism

Sterkiella histriomuscorum, formerly Oxytricha trifallax, is a ciliate species in the genus Sterkiella, known for its highly fragmented genomes which have been used as a model for ciliate genetics.

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

Oxytrichidae is a family of ciliates in the order Sporadotrichida. Oxytrichidae are morphologically diverse, ranging in length from 40 micrometres to 400 micrometers. They are generally elliptical in shape with some very flexible while others are rigid. Like other ciliates, Oxytrichidae have two or more nuclei: a large macronucleus that generally stretches across much of the cell body, and one or more smaller micronuclei.

<i>Pseudomonilicaryon anser</i> Species of single-celled organism

Pseudomonilicaryon anser is a species of unicellular ciliates in the family Dileptidae, also known under the names Dileptus anser and Dileptus cygnus. The species is common in fresh water ponds, stagnant pools, mosses and soils.

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

Kentrophoros is a genus of ciliates in the class Karyorelictea. Ciliates in this genus lack a distinct oral apparatus and depend primarily on symbiotic bacteria for their nutrition.

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

Tracheloraphis is a genus of ciliates in the family Trachelocercidae.

<span class="mw-page-title-main">Stentor roeselii</span> Species of single-celled organism

Stentor roeselii is a free-living ciliate species of the genus Stentor, in the class Heterotrichea. It is a common and widespread protozoan, found throughout the world in freshwater ponds, lakes, rivers and ditches.

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

Halteria, sometimes referred to as the jumping oligotrich, is a genus of common planktonic ciliates that are found in many freshwater environments. Halteria are easy to locate due to their abundance and distinctive behaviour with observations of Halteria potentially dating back to the 17th century and the discovery of microorganisms. Over time more has been established about their morphology and behavior, which has led to many changes in terms of classification.

References

  1. 1 2 3 Vďačný, Peter, and Wilhelm Foissner. Monograph of the dileptids (Protista, Ciliophora, Rhynchostomatia). Land Oberösterreich, Biologiezentrum/Oberösterreichische Landesmuseen, 2012: 294-314
  2. Stephen Miller (2007), The Predatory Behavior of Dileptus anser. Journal of Eukaryotic Microbiology, Volume 15 Issue 2, Pages 313 - 319
  3. Vďačný, Peter, and Wilhelm Foissner. Monograph of the dileptids (Protista, Ciliophora, Rhynchostomatia). Land Oberösterreich, Biologiezentrum/Oberösterreichische Landesmuseen, 2012: 30
  4. A. L. Yudin and Z. I. Uspenskaya (2006), Mating types in the ciliate Dileptus anser. Inheritance and genetic determination. Citologiâ volume 48, issue 4, pp. 364-374 ISSN 0041-3771. Abstract at inst.fr.
  5. Dujardin, Félix, and Georges-Louis Leclerc Buffon. Histoire naturelle des zoophytes: infusoires, cómprenant la physiologie et la classification de ces animaux, et la manière de les étudier a l'aide du microscope. Librairie encyclopédique de Roret, 1841.