Jakobida

Thisa is an image of ATCC strain 50688, picture taken April 2006. At the time of writing this genus and species have not been formally introduced into the literature, even though the name is used by ATCC and has also appeared in the scientific literature (Marx, Baumgartner, Kannan, Braun, Lang, and Burger. 2003. Structure of the bc1 complex from Seculamonas ecuadoriensis, a jakobid flagellate with an ancestral mitochondrial genome.Mol Biol Evol. 20:145-53.). ATCC data on this organism.

Jakoba (yak-obe-a) one of the excavate flagellates, so called because of the ventral groove or gutter in which the recurrent flagellum lies. One anterior flagellum is held in front of the cell like a crook (shepherd+s not criminal). Originally from marine sites. Phase contrast micrograph.

Images of an un-named species of Jakova. The recurrent flagellum has a vane near its base, and lies in the ventral groove that serves to define the broader grouping to which the jakobids belong - the excavates. The mitochondrion extends along the dorsal margin of the cell and is visible as a dark inclusion. Material from Tom Nerad, images by Charley O'Kelly. Phase contrast.

Jakoba libera (Ruinen, 1938) Patterson, 1990. The organism is a biflagellated protist with an acutely obovate cell body measuring 6-9.5 microns long, with most cells 7-8 microns in length. The anterior flagellum is inserted apically. It measures about one and a half times the length of the body and is held in a hook shape. The posterior flagellum is inserted slightly subapically, is about the same length as the anterior flagellum and lies in a ventral groove of the body. Normally it beats actively. Both flagella are acronematic. The cells may swim but usually adhere to debris with the crook of the anterior flagellum. They may deform and squirm when compressed in debris. During feeding, the posterior flagellum creates a current of water from which bacteria are removed. Bacteria are collected in the groove, ingested, and the resulting food vacuoles are found mostly in the posterior part of the cell.

Phase contrast image of cell from ATCC strain 50422. ATCC data on this organism.

Histiona (hist-ee-own-a) is a jakobid flagellate related to Jakoba. As with other excavates, there is a ventral groove and the flagella insert at the head of the groove. There are two flagella, one lying in the groove and one curving outwards from the point of insertion. The margins of the groove can be mistaken for flagella. Unlike most other excavates, Histiona sits in a stalked lorica when feeding. Phase contrast.

Histiona (hist-ee-own-a) is a jakobid flagellate related to Jakoba. As with other excavates, there is a ventral groove and the flagella insert at the head of the groove. There are two flagella, one lying in the groove and one curving outwards from the point of insertion. The margins of the groove can be mistaken for flagella. Unlike most other excavates, Histiona sits in a stalked lorica when feeding. Lorica with a cyst is evident. Phase contrast.

Histiona (hist-ee-own-a) is a jakobid flagellate related to Jakoba. As with other excavates, there is a ventral groove and the flagella insert at the head of the groove. There are two flagella, one lying in the groove and one curving outwards from the point of insertion. Unlike most other excavates, Histiona sits in a stalked lorica when feeding. This is a lorica and an enclosed but vacated cyst. Phase contrast.

Histiona (hist-ee-own-a) is a jakobid flagellate related to Jakoba. As with other excavates, there is a ventral groove and the flagella insert at the head of the groove. There are two flagella, one lying in the groove and one curving outwards from the point of insertion. These are the characteristics of the feeding cells, but they can also separate from the lorica and swim around. This is a swimming cell (theront). Phase contrast.

Histiona, small heterotrophic flagellate, located ina stalked lorica, gives the impression of relaxing. From a freshwater pond near Boise, Idaho.

Reclinomonas (ree-cline-owe-moan-ass) is a jakobid flagellate, cells lie recumbent in a stalked lorica, two similar flagella emerge from the anterior apex, one often lying within a ventral groove and the other projecting. Population in debris. Phase contrast.

Reclinomonas (ree-cline-owe-moan-ass) is a jakobid flagellate, cells lie recumbent in a stalked lorica, two similar flagella emerge from the anterior apex, one often lying within a ventral groove and the other projecting. May also have a rod projecting from the ventral face. Nuclei located anteriorly. Phase contrast.

Reclinomonas (ree-cline-owe-moan-ass) is a jakobid flagellate, cells lie recumbent in a stalked lorica, two similar flagella emerge from the anterior apex, one often lying within a ventral groove and the other projecting. May also have a rod projecting from the ventral face. Nucleus located anteriorly, contractile vacuole dorsal (near lower face in this image). Phase contrast.

Jakoba incarcerata Bernard et al., 2000. Cells are 4 to 10microns Two flagella arise slightly sub-apically. They may be slightly acronematic. The anterior flagellum is usually shorter than the length of the cell. The posterior flagellum is up to one and a half times the length of the cell and may appear proximally thickened. The nucleus is located subapically. Food vacuoles containing bacteria are common. A refractile granule is frequently located in the middle of the cell. Typical cells are crescent-shaped with a groove occupying three quarters of the ventral face. The posterior flagellum beats with a short wavelength and amplitude pattern within the groove, often attaching to the posterior margin but with the distal portion free. Some cells lack a groove, have an ovoid to irregular profile, but have usually a posterior tail. Transformation from a grooved to a tailed profile has been observed. Grooved or tailed cells may attach to the substrate by a hooked anterior flalgellum or the tip of the posterior flagellum. Tailed cells often stick to the substrate by the tail, the cell body or irregular extensions thereof. Grooved, or more commonly, tailed cells may swim with a smooth spiral path, with the anterior flagellum directed forward. Occasionally, non-grooved cells were observed with anterior flagella up to four times the length of the cell directed posteriorly in a curving arc. These cells swim or attach to the substrate by the cell body. Electron-micrographs of cells from the type culture shows a single vane on the dorsal side of the posterior flagellum.