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Trachelomonas (track-ell-owe-moan-ass) is an autotrophic euglenid flagellate. The genus is distinguished from others because the cells live within a loose fitting lorica with a small opening. The lorica of many species is elaborated with spikes or spines. The lorica accumulates metal salts with age, becoming brown and brittle and often obscuring the bright green colour of the chloroplasts within the cell. Red eyespot evident near the anterior of the cell. There is one emergent flagellum which emerges from the opening of the lorica. Most freshwater but occasionally found in brackish habitats. Differential interference contrast.
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Euglena gracilis (you-glean-a grass-ill-iss). Euglena is the iconic genus of euglenoid flagellates, and this is probably the most familiar of the species. The body of most euglenids is typically spindle-shaped, although two flagella arise in a pocket within the cell only one emerges (and sometimes none). The body can squirm, and the cell has one to many chloroplasts. At the anterior of the body a thin channel (flagellar canal) leads to the flagellar pocket, and alongside this is a contractile vacuole. A red eyespot or stigma is associated with the bottom of the flagellar canal. This image shows the nucleus (central). the region of the flagellar pocket as the lighter region to the right, the associated stigma, the single emergent flagellum, and several green chloroplasts. Phase contrast.
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Euglena sanguinea - a brightfield portrait of this slow swimming species pigmented with hematochrome granules. Granules aggregate as seen here in low light conditions and disperse with increases in either water temperature or light intensity. Flagellum typically body length but not seen here. Small spindle shaped chloroplasts often spirally aligned with pellicular striations. Also referred to as E. rubra. Collected from freshwater pond near Boise, Idaho.
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Portrait of Trachelomonas, a loricate euglenoid flagellate. Lorica in this species has distinct collar with an aperture through which a single flagellum emerges. The lorica has been fractured exposing the cell body with its prominent stigma and thin discoid peripheral plastids. From freshwater pond near Boise, Idaho.Brightfield.
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Euglena gracilis (you-glean-a grass-ill-iss). Euglena is the iconic genus of euglenoid flagellates, and this is probably the most familiar of the species. These cells have been compressed, but the body is usually spindle-shaped. Although two flagella arise in a pocket within the cell only one emerges. The body can squirm, and the cell has many chloroplasts. At the anterior of the body a thin channel (flagellar canal) leads to the flagellar pocket, and alongside this is a contractile vacuole. A red eyespot or stigma is associated with the bottom of the flagellar canal. This image shows the nucleus (central). Differential interference contrast.
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Detail of the anterior end of a Euglena cell, collected at Beaver Lake, showing the flagellar pocket, a very short flagellum with a swollen basal region (the flagellum is not long enough even to project from the front of the cell). The eyespot is closely associated with the flagellum.
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Euglena gracilis. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using differential interference contrast optics. This work was supported by the Australian Biological Resources Study.
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This image of Euglena, collected from Beaver Lake, emphasizes the disk- shaped chloroplasts. The front of the cell is to the left. The light area is called the reservoir. Adjacent to this region is the red eyespot that helps to control the direction in which the cells move. The granular region in the center of the cell is the nucleus.
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Whole cell, the dark eyespot is near the front and adjacent to it is the flagellar pocket / reservoir / contractile vacuole region. the nucleus is the clear structure near the posterior of the cell. The positions of about 6 large plastids can be worked out. Animations by Rosemary Arbur of flagellar beat patterns are available
here.
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Euglena. Cyst observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using differential interference contrast optics. This work was supported by the Australian Biological Resources Study.
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Euglena mutabilis (you-glean-a mew-tab-ill-iss) is one of the worm-like species of Euglena. Typically there is no emergent flagellum or a very short one. Yet, the organism can be distinguished as a euglenid because of the bright green plastids, the eyespot that lies external to any plastid, and because the cells can squirm. The plastids are large-ish plate like structure which wrap themselves around the cell adjacent to the pellicle. The margins of individual plastids are hard to distinguish in this micrograph. Differential interference contrast.
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Euglena. Cyst observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using differential interference contrast optics. This work was supported by the Australian Biological Resources Study.
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Euglena mutabilis (you-glean-a mew-tab-ill-iss), is a moderately long but usually thin worm-like euglena. It may or may not have an emerging flagellum, and distinguished from similarly-shaped species by the relatively small number of large chloroplasts - about four can be clearly made out in this cell. The image also shows (from anterior - top): stigma or eyespot, flagellar pocket, and nucleus in the middle of the cell. Typically very metabolic - squirming a lot. Differential interference contrast.
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Euglena. The picture to the left shows euglenids and some diatoms concentrated within a narrow beam of light using photokinetic reactions to changing light intensities. The image to the right shows the cells beginning to move outwards after the beam of light has been 'opened up'. This work was supported by the Australian Biological Resources Study.
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Euglena mutabilis is a worm like gliding Euglena which rarely swims. Sizes vary from 53-206 microns long, with 10 or more (up to 100), disk-shaped, plastids situated just below surface. It is distinguished from another worm like species (E. mutabilis) by the much larger number of plastids. The cells contain small rod and oval-shaped paramylon bodies scattered throughout the cytoplasm. Anterior flagellum usually about a quarter of the cell length, but may not be emergent, or be a short stump, or up to 0.5 the cell length. There are two flagella inserting in the flagellar pocket which can be seen behind the red stigma or eyespot. May produce cysts. The large tapioca-like nucleus is located just behind the mid line. Surface striations not visible. Metabolic (can squirm). Differential, interference contrast.
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Single cell without an emergent flagellum. The eyespot is the red structure near the front of the cell, and there is a contractile vacuole near it. the clear, slightly speckled, region near the center of the cell is the nucleus.
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Euglena mutabilis is a worm like gliding Euglena which rarely swims. With more than 10 (up to 100), disk-shaped, plastids situated just below surface. It is distinguished from another worm like species (E. mutabilis) by the much larger number of plastids. Plastids are disc shaped. Also evident at the front of the cell is the emergent flagellum, the flagellar canal, the stigma, and flagellar pocket. Differential interference contrast.
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Collected from Cumloden Swamp on July 8, 2002.
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Euglena mutabilis (you-glean-a mew-tab-ill-iss), is a moderately long but usually thin worm-like euglena. It may or may not have an emerging flagellum, and distinguished from similarly-shaped species by the relatively small number of large chloroplasts. The image also shows (from anterior - top): flagellar pocket, stigma or eyespot, small paramylon granules, and nucleus in the middle of the cell. Typically very metabolic - squirming a lot as is suggested by the different profiles in this image. Phase contrast.
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This phase contrast micrograph of an un-named species of euglena shows the way that euglenid flagella beat. The flagellum is thrown into loops and these are pushed along the flagellum from base to tip. Several loops can be seen here. Cell with grass-green plastids and red eyespot.
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Euglena mutabilis (you-glean-a mew-tab-ill-iss), is a moderately long but usually thin worm-like euglena. It may or may not have an emerging flagellum, and distinguished from similarly-shaped species by the relatively small number of large chloroplasts. The image also shows (from anterior - top): flagellar pocket, stigma or eyespot, small paramylon granules, and nucleus in the middle of the cell. Typically very metabolic - squirming a lot. Differential interference contrast.
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Euglena. Collected by ATOL team in Cedar Pond, Woods Hole during the Protistology Workshop at MBL, October-November 2005. Isolation and art by Adrian Reyes-Prieto.
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Euglena mutabilis (you-glean-a mew-tab-ill-iss), is a moderately long but usually thin worm-like euglena. It may or may not have an emerging flagellum, and distinguished from similarly-shaped species by the relatively small number of large chloroplasts. The image shows the palmelloid mass that can be formed under some circumstances. Many hundred or thousands of cells form a skin, or film or mass in which the individual cells are embedded in a common matrix. Cells will become more active and work their way out of the mass when they are disturbed. Phase contrast.
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Moving Euglena. By Bob Moore and Dan Lahr