Heteronematina

Entosiphon (ent-owe-siphon) heterotrophic euglenid, with a strongly developed ingestion organelle that is easy to see with the light microscope. With two flagella, the anterior one beats with a sweeping motion, the posterior or recurrent one trails under moving cells (and seems to be more important in the process of moving the cells around). Ingests bacteria and detritus. Not capable of metaboly, but the mouth (siphon) can make slight pumping movements. Common and widespread in freshwater habitats. Phase Contrast.

Entosiphon (ent-owe-siphon) heterotrophic euglenid, with a strongly developed ingestion organelle that is easy to see with the light microscope. With two flagella, the anterior one beats with a sweeping motion, the posterior or recurrent one usually trails under moving cells (and seems to be more important in the process of moving the cells around). Ingests bacteria and detritus. Not capable of metaboly, but the mouth (-siphon+) - to the right - can make slight pumping movements. Common and widespread in freshwater habitats. Differential interference contrast.

This is a transmission electron micrograph of the siphon (or mouth, or ingestion organelle) of Entosiphon sulcatum. There are three stout rods comprised of microtubules, and four lamellae which seem to assist in pushing food into the body. Each of the microtubules is about 25 nm in diameter. This species eats filamentous bacteria and other moderately large particles, and this presumably requires a stiff ingestion structure.

Entosiphon sulcatum. 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.

The ingestion apparatus is revealed by immunofluorescence microscopy.

Electron micrograph of a grazing thin section along the length of the recurrent flagellum, showing axoneme to the upper left, the crystalline paraxial rod, membrane, and thin hairs over the flagellar surface.

Transmission electron micrograph of a thin section across the anterior part of the cell. The two flagella lie in the flagellar pocket / reservoir (the recurrent flagellum is the one with the more crystalline paraxial rod). This species uses this flagellum to adhere to the substrate as it glides. The ingestion apparatus, with three microtubular rods and four lamella, lies in the lower right part of the cell. The cell surface has folds.

Bright field light micrograph of a cell dried in a suspension of Nigrosin. The stain dries around the cell and in surface irregularities. It therefore shows up the surface folds. The recurrent (trailing) flagellum is the thicker one.

Transmission electron micrograph of a thin section across a fold in the cell surface. Several cytoskeletal elements are associated with the fold. The proteinaceous epiplasm underlies the whole fold, and this is subtended by microtubules. Darker material is associated with the crest of the fold and with the bottom of the fold. the circular structures upper right are sections through extrusomes.

Entosiphon ovatus Stokes,1885. Body ovate, somewhat depressed, a little less than twice as long as wide, rounded posteriorly, narrowed anteriorly, and slightly curved toward the ventral aspect, the frontal border somewhat emarginated on the left side, the cuticular surface traversed by ten or twelve longitudinal sulci, the two flagella inserted near together on the left side of the ingestion organelle, the posterior or trailing appendage about twice as long as the body, the anterior or vibratile not exceeding the body in length, ingestion organelle protrusible, extending backwards for fully four-fifths of the entire length of the body, contractile vacuole single, near the left border of the frontal margin, nucleus spherical, near the centre of the left border. Reproduction by longitudinal fission. Length of body 25-28 microns Probably the same as E. sulcatum.

Ploeotia azurina Patterson and Simpson, 1996. Cells measure 10-16 microns, average 13.5 microns Profile ovate, dorsally convex with 7 ridges (2 forming the margins) running longitudinally or at a slightly oblique angle. Usually only 6 ridges can be seen at any time. Cells may be flattened ventrally with a mid-ventral ridge arising anteriorly at the opening of the flagellar pocket. In some cells two lateral ventral ridges may also be seen and these cells appear less ventrally flattened. Posterior flagellum 2 - 3.5 times cell length and appears thick, anterior flagellum about the same length as the cell. Posterior end of cell tapers. Cell moves by gliding, without Anisonema-like reversals.

Urceolus (urk-ee-owe-less) is one of the heteronematine euglenids, all of which are very metabolic and have an ingestion organelle. Urceolus is one of the more rarely reported genera and is distinguished by the flared anterior end of the cell. It has a single emergent flagellum and an ingestion organelle visible as two rods in the cell just adjacent to where the flagellum comes to an arching end within the cell. The emergent flagellum is thickened as it is in most euglenids. Mostly eats diatoms and detritus. Phase contrast.

Urceolus (urk-ee-owe-less) is one of the heteronematine euglenids, all of which are very metabolic and have an ingestion organelle. Urceolus is one of the more rarely reported genera and is distinguished by the flared anterior end of the cell. It has a single emergent flagellum and an ingestion organelle visible as two rods in the cell just adjacent to where the flagellum comes to an arching end within the cell. The emergent flagellum is thickened as it is in most euglenids. Mostly eats diatoms and detritus. Side view. Phase contrast.

Urceolus (urk-ee-owe-less) is one of the heteronematine euglenids, all of which are very metabolic and have an ingestion organelle. Urceolus is one of the more rarely reported genera and is distinguished by the flared anterior end of the cell. It has a single emergent flagellum and an ingestion organelle visible as two rods in the cell just adjacent to where the flagellum comes to an arching end within the cell. The emergent flagellum is thickened as it is in most euglenids. Mostly eats diatoms and detritus. Differential interference contrast.

Urceolus (urk-ee-owe-less) is one of the heteronematine euglenids, all of which are very metabolic and have an ingestion organelle. Urceolus is one of the more rarely reported genera and is distinguished by the flared anterior end of the cell. It has a single emergent flagellum and an ingestion organelle visible as two rods in the cell just adjacent to where the flagellum comes to an arching end within the cell. The emergent flagellum is thickened as it is in most euglenids. Mostly eats diatoms and detritus. Nucleus and polysaccharide storage granules are evident in this cell. Differential interference contrast.

Urceolus (urk-ee-owe-less) is one of the heteronematine euglenids, all of which are very metabolic and have an ingestion organelle. This image shows the ingestion apparatus, which is made up of two rods (which seem hollow) and a cap structure. Mostly eats diatoms and detritus. Nucleus and polysaccharide storage granules are evident in this cell. Differential interference contrast.

Urceolus (urk-ee-owe-less) is one of the heteronematine euglenids, all of which are very metabolic and have an ingestion organelle. Urceolus is one of the more rarely reported genera and is distinguished by the flared anterior end of the cell. It has a single emergent flagellum and an ingestion organelle visible as two rods in the cell just adjacent to where the flagellum comes to an arching end within the cell. The emergent flagellum is thickened as it is in most euglenids. Mostly eats diatoms and detritus. This image also shows the ridged pellicle. Differential interference contrast.

Urceolus (urk-ee-owe-less) is one of the heteronematine euglenids, all of which are very metabolic. This image shows the ridged pellicle. Phase contrast.

Urceolus, a colorless phagotrophic euglenid flagellate. The cell is flask-shaped and flexible with visible pellicular striations (obscured in some species by adhering particles). There is a flared collar anteriorly surrounding the cytostome. There is a long thick emergent flagellum, which is most active at the tip as seen in Peranema. An ingestion apparatus composed of two rods is present although not visible in these images. The posteriorly located nucleus is visible. From freshwater pond near Boise, Idaho. Oblique illumination.

Urceolus, a colorless phagotrophic euglenid flagellate. The cell is flask-shaped and flexible with visible pellicular striations (obscured in some species by adhering particles). There is a flared collar anteriorly surrounding the cytostome. There is a long thick emergent flagellum which is most active at the tip as seen in Peranema. An ingestion apparatus composed of two rods is present although not visible in these images. The posteriorly located nucleus is visible. From freshwater pond near Boise, Idaho. Oblique illumination.