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Blepharisma

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Domain  Eukaryota
Scientific name  Blepharisma
Higher classification  Blepharismidae
Order  Heterotrich
Family  Blepharismidae
Phylum  Ciliophora
Rank  Genus
Blepharisma Blepharisma is a microphagus filter feeder that PSYCHOLOGY PSY 203
Similar  Blepharisma japonicum, Stentor, Heterotrich, Spirostomum, Hypotrich

Blepharisma mpg


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.

Contents

Blepharisma Protist Images Blepharismidae

All members of the genus possess a long series of membranelles on the left side of the oral groove, and an "undulating membrane" (a structure resembling a flap, scarf or small sail, composed of long cilia fused together as a single sheet) on the right side of the peristome, toward the posterior.

Blepharisma Phycokey Chilodonella images

Certain species of Blepharisma have served as model organisms for scientific research. Since some varieties are easily cultured and readily available from scientific supply houses, they are a common object of study in school science classes.

Blepharisma Freshwater and other microorganisms from Germany Blepharisma

Blepharisma friends


Appearance

Blepharisma MicUK Two Marvelously Weird Ciliates Blepharisma and Climacostomum

Blepharisma may be as small as 50 micrometres in length, or as large as 1 mm (though normal size range is between 75 and 300 micrometres). Body shape varies within the genus. The type species of the genus, B. persicinum, is ellipsoidal. Blepharisma lateritium is teardrop-shaped, with a rounded posterior; while Blepharisma elongatum and Blepharisma sphagni are long and thin, tapering at the posterior into a tail-like point.

Blepharisma httpsuploadwikimediaorgwikipediacommonsthu

All species are uniformly ciliated, with the cilia arranged in longitudinal rows, and stripes of pigment alternating between rows of cilia. The pink or red pigmentation may be quite pale, and in certain cases it is absent altogether. A contractile vacuole, often quite large, is located in the posterior. The Macronuclei can take a variety of forms. Depending on species and phase of life, they may be rod-shaped, ovoid, spherical, or moniliform (like a rosary, or string of beads).

Reproduction

Blepharisma Blepharisma

Like all ciliates, Blepharisma can reproduce by binary fission, dividing transversally. They also engage in a type of sexual reproduction known as ciliate conjugation, a process through which genetic material can pass directly from one cell to the other. In conjugation, two organisms come into close contact, and a temporary cytoplasmic bridge forms between them. The micronuclei of each cell then undergo meiosis, and haploid micronuclei pass from one individual to the other. This permits the reshuffling of hereditary characteristics, as in other types of sexual reproduction. Conjugation is immediately followed by binary fission of the two conjugants.

Blepharisma BLEPHARISMA

In Blepharisma, as in some other ciliates, chemical substances called gamones are used to induce conjugation by stimulating interaction between compatible mating partners.

Blepharisma Blepharisma

Although Blepharisma are able to undergo a form of sexual reproduction that involves selfing, ordinarily sexual reproduction involves interaction of cells of different mating types. There are two mating types (I and II), each type excreting a specific pheromone (termed gamone 1 and gamone 2, respectively). When sexually mature mating-type I cells are moderately starved, they autonomously produce and secrete gamone I. Gamone 1 specifically acts on mating-type II cells, transforming them so that they can unite with type I cells, and inducing them to secrete gamone 2. Gamone 2 then transforms type I cells so that they can unite with type II cells. Cells that can unite may then undergo conjugation. Sexual reproduction involving interaction of opposite mating types promotes outcrossing and the masking of deleterious recessive mutations in the diploid phase of the sexual cycle.

Feeding and behavior

Blepharisma feed on a variety of smaller organisms, including bacteria, flagellate algae, rotifers, other ciliates and even smaller members of the same species. Experiments with Blepharisma undulans have shown that cannibalism causes gigantism. When individuals are given a diet of smaller Blepharisma, or certain ciliates (particularly Colpidium colpoda), they grow to a relatively enormous size. As long as their diet remains unchanged, cannibal giants will divide to produce more giants. When large prey become unavailable, the offspring will revert to normal size.

Blepharisma are markedly photophobic, and when light levels are increased will seek out darkened areas. The ability to detect light is accomplished with photosensitive pigment granules located just under the plasma membrane of the cell. The pigment in these granules is Blepharismin, the same substance that gives Blepharisma their characteristic pinkish color.

List of Species

  • B. americanum Suzuki, 1954
  • B. bimicronucleatum Villeneuve-Brachon 1940
  • B. bothrostoma Mermod 1914
  • B. botezati Lepsi, 1926
  • B. coeruleum Gajevskaja, 1927
  • B. caudatus Dumas 1937
  • B. clarissimum Kahl, 1928
  • B. dawsoni Christie & Hirshfield 1967
  • B. dileptus Kahl, 1928
  • B. elegans Vuxanovici 1963
  • B. elongatum (Stokes, 1884) Kahl, 1926
  • B. falcatum Gelei 1954
  • B. galianoi Fernandez-Leborans 1979
  • B. grayi Hartwig & Parker, 1977
  • B. halophila Ruinen 1938
  • B. hyalinum Perty, 1852
  • B. intermedium Bhandary, 1962
  • B. ichthyoides V. Gelei, 1933
  • B. japonicum (Suzuki, 1954) Giese, 1973
  • B. lateritium (Ehrenberg, 1831) Kahl, 1932
  • B. lentis Gelei 1954
  • B. melana Borror, 1963
  • B. minima Lepsi, 1926
  • B. multinucleata Dragesco, 1960
  • B. musculus Penard, 1922
  • B. ovalis Dumas 1937
  • B. ovatum Penard, 1922
  • B. parasalinarum Dragesco 1997
  • B. persicinum Perty, 1849
  • B. salinarum Florentin, 1899
  • B. seshachari Bhandary, 1962
  • B. sphagni Lepsi, 1926
  • B. steini Kahl, 1932
  • B. tardum Kahl, 1928
  • B. undulans Stein, 1868
  • B. velatum Vacelet, 1961
  • B. vestitum Kahl, 1928
  • B. violaceae Tucolesco 1962
  • B. vitreum Lepsi 1957
  • B. wardsi Hirshfield, Isquith & Bhandary, 1965
  • References

    Blepharisma Wikipedia


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