Cirral Anlagen Research Articles

Morphology and Cell Division of Saudithrix terricola n. gen., n. sp., a Large, Stichotrich Ciliate from Saudi Arabia

The morphology and main ontogenetic traits of a new stichotrich ciliate, Saudithrix terricola Foissner, AL-Rasheid and Berger n. gen., n. sp., from a terrestrial habitat in Saudi Arabia were investigated using live observation, protargol impregnation, and scanning electron microscopy. Saudithrix terricola is characterized by a large (200-350 x 70-150 microm), flexible body; an adoral zone formed like a three-quarter circle; a sickle-shaped buccal lip with a widened paroral forming a cyrtohymenid pattern with the endoral; 11 frontal and frontal-ventral cirral rows (including right marginal rows) and one left marginal row covering the ventral side; two buccal cirri; six to nine transverse cirri; three dorsal kineties; and two macronuclear nodules. The resting cyst is about 85 microm across, has a smooth wall, and a fluffy mucous layer. Most cirral anlagen originate within the parental rows and are arranged side by side, the proximal portion of the adoral zone of membranelles is reorganized, and some parental dorsal bristles are maintained. Neither the morphological nor the ontogenetic data reveal the systematic position of Saudithrix within the stichotrichs. The term multicorona is introduced and describes a frontal ciliature composed of four or more cirral bows.

Reconsideration of the morphogenesis in the marine hypotrichous ciliate, Aspidisca leptaspis Fresenius, 1865 (Protozoa, Ciliophora)

Morphogenetic events during division of the marine hypotrichous ciliate, Aspidisca leptaspis were investigated. The oral primordium of the opisthe develops hypoapokinetally in a sub-surface pouch posterior to the rear parental adoral zone, as in congeners. The parental adoral zones of membranelles are inherited by the proter. The proter's buccal cirrus develops from an “extra” anlage, which is formed de novo on the cell surface at an early stage of morphogenesis. Basal bodies in the oral primordium seem not to contribute to the formation of the buccal cirrus of the opisthe, which originates independently within the pouch opposite to the oral primordium and then migrates onto the cell surface. The paroral membrane derives from the posterior end of the oral primordium. Five frontoventral-transverse cirral anlagen are also formed de novo, initially as primary primordia, and develop into 3:3:2:2:2 cirri, respectively, in both dividers. Each of the four dorsal kineties evolves from an intrakinetal anlage in both proter and opisthe. Replication bands progress from the centre to the two ends of the macronucleus during the first half of the morphogenetic process, before this nucleus shortens and divides. The present investigation has clarified division processes within this species and confirmed some morphogenetic differences within the genus.

Observations on the morphology and morphogenesis of a new marine urostylid ciliate, Parabirojimia similis nov. gen., nov. spec. (Protozoa, Ciliophora, Hypotrichida)

The morphology, infraciliature and morphogenesis of the hypotrichous ciliate, Parabirojimia similis nov. gen., nov. spec., collected from scallop-culturing waters off Qingdao (Tsingtao), China, are described using living observations and protargol silver impregnation. The new genus Parabirojimia is characterized thus: Urostylidae with clearly differentiated frontal cirri; buccal and transverse cirri present, caudal and frontoterminal cirri absent; one left and several right rows of marginal cirri, which derive from individual anlagen within each parental row; transverse cirri originate within fronto-ventral-transverse cirral anlagen and part of right marginal cirral anlagen. The diagnosis for Parabirojimia similis nov. spec. is as follows: in vivo 140–300 × 30–50 μm, elongated elliptical body outline; 5–8 right marginal rows; adoral zone of membranelles composed of 37–54 membranelles, bipartite with a snout-like protrusion of the frontal field between the anterior and posterior portions; 3 enlarged frontal, 7–13 midventral, 1 buccal and 3–11 transverse cirri; usually 1 ventral row composed of 15–56 cirri; usually with 3 complete dorsal kineties; 3–6 macronuclear nodules and about 3–8 micronuclei; marine habitat. The main features of divisional morphogenesis are: 1) the parental structure of the oral apparatus is partly renewed in the proter; 2) each parental marginal cirral row develops 2 separate anlagen intrakinetally; 3) transverse cirri are derived from the fronto-ventral-transverse cirral anlagen and part of right marginal cirral anlagen; 4) each parental dorsal kinety forms 2 separate anlagen intrakinetally.

Divisional morphogenesis in the marine ciliate Holosticha warreni (Ciliophora: Hypotrichida)

The cortical development of the marine hypotrichous ciliate Holosticha warreni, found in coastal waters near Qingdao, China, was investigated using the protargol impregnation method. In the proter, disorganization of the parental adoral zone of membranelles and undulating membranes contributes to the formation of its oral primordia which replace the parental buccal apparatus completely. Cirral anlagen in both division parts derive from the breaking of primary primordia. Most midventral cirri join in the formation of these primordia which occurs de novo separately from the oral primordia. Each of the 11 to 13 oblique streaks divides into three segments (new cirri) while the last two anlagen produce four each. Two frontoterminal cirri derive from the posteriormost anlage. The marginal rows develop from the parental structure. The generation mode of dorsal kineties is of the ‘one group type’ without forming caudal cirri.

Observations on Morphogenesis in a marine ciliate Tachysoma ovata (Protozoa: Ciliophora: Hypotrichida)

Divisional morphogenesis of the marine hypotrichous ciliate, Tachysoma ovata was investigated based on protargol impregnated specimens. Its morphogenesis reveals the following peculiarities: (1) there is a definite period during which the anterior part of the newly formed adoral zone of membranelles (AZM) in the opisthe connects with the parental AZM which remains unchanged during the morphogenesis. (2) The anlagen of left and right marginal rows do not develop simultaneously. (3) The replication processes of macronuclear segments are not recognizable during cell division. It is likely that the replication takes place during the interphase. (4) The origin of the fronto-ventral-transverse (FVT) cirral anlagen in the opisthe is characteristic: in other Tachysoma spp. these primordia are generated either from differentiated parental ciliatures (or are orientated by pre-existent organelles), or by division of the proter's FVT-cirral primordia. (5) The primordium of the undulating membranes in the proter always keeps the form of two streaks (so-called ‘semi-anlagen’). There is no conspicuous dedifferentiation or reorganization of the undulating membranes. A morphogenetic comparison with other species of this genus was carried out.

Morphology and morphogenesis of Parentocirrus hortualis nov. gen., nov. spec: A new genus within the redefined family Kahliellidae sensu Eigner 1995 (Ciliophora, Hypotrichida)

Summary The morphology and the divisional morphogenesis of the freshwater hypotrich ciliate Parentocirrus hortualis nov. gen., nov. spec, has been investigated using living organisms and protargol impregnation. The morphogenesis commences with the proliferation of basal bodies for the opisthe's oral primordium left of two anteriormost and unchanged transverse cirri, indicating an apokinetal development. This oral primordium generates three cirral anlagen for the opisthe. The proter develops these anlagen from the undulating membranes, the buccal cirri and the posterior frontal cirri. In proter and opisthe the left ventral row is usually developed by within anlagen, whereas the right and middle ventral row is usually developed by typical V-shaped anlagen, generated by the middle ventral row. In few specimens the left and the middle ventral row for the proter develop by V-shaped anlagen, generated by the left ventral row. The right ventral row does not take part in anlagen formation and is usually but not always completely resorbed during morphogenesis. Thus, the three long ventral cirral rows on the right side of the body and the V-shaped primordia, which indicate typical neokinetal development, justify the assignment of the new genus Parentocirrus to the family Kahliellidae sensu Eigner. Marginal rows and dorsal kineties develop within the parental structures, dorsomarginal rows develop from the right marginal row. During divisional morphogenesis the proter's oral structures show some signs of cryptic reorganization, indicated by the flattening of the buccal cavity, the disappearence of the cortical ridge where the undulating membranes arise and the parallel arrangement of the reorganized paroral and endoral membrane.

Morphogenesis of the marine ciliate Diophrys oligothrix Borror, 1965 during the cell division (protozoa, ciliophora, hypotrichida)

Summary Morphogenetic events during division of the marine hypotrichous ciliate Diophrys oligothrix were investigated by light microscopy on protargol impregnated specimens. The morphogenesis of both the ventral and dorsal infraciliature proceeds in a very similar way to that in D. scutum . The opisthe oral primordium (OP), which develops in a subsurface pouch, forms de novo anterior to the parental transverse cirri. Basal bodies formed in the OP field do not contribute to any other cirral anlagen. Only the rear part of the parental adorai zone of membranelles (AZM) is reorganized during the later morphogenetic process and then was inherited by the proter. Both the endoral and paroral membrane (UM) develop from an “extra” anlage which seems to derive from the posterior end of the reorganized AZM in the proter and from the oral primordium in the opisthe. All cirral anlagen form de novo and do not develop in association with any parental structures. Each of the 4 dorsal kineties evolves from a separate dorsal kinety anlage in both proter and opisthe. The replication band at the distal end of each macronucleus proceeds proximally and disappears as the two nuclear segments fuse. This investigation documents several ontogenetic differences among the species of the genus Diophrys . The morphogenetic process in our population differs from that in D. scutum in the position of the oral primordium which is distinctly anterior to the transverse cirri and between the marginal cirri, the reorganization of the parental AZM is limited merely to the last 1/3 of its length and is relatively inconspicuous. In contrast to the previous report, the origin of the UM and paroral cirrus in both proter and opisthe is apparently connected with the oral primordium (in opisthe) or reorganizing part of parental AZM and UM (in proter).

Divisional Morphogenesis in Orthoamphisiella stramenticolaEigner & Foissner, 1991 and O. grelli nov. spec. (Ciliophora, Hypotrichida)

Summary Divisional morphogenesis was investigated in Orthoamphisiella stramenticola Eigner & Foissner , 1991 and O. grelli nov. spec, using protargol impregnation. Orthoamphisiella grelli nov. spec, differs from O. stramenticola mainly by having only 2 macronuclear segments. A Japanese population of O. stramenticola is also described. It differs from the type population mainly by the absence of a third short ventral row. Divisional morphogenesis is very similar in both species. The oral primordium originates apokinetally and develops the oral apparatus and the left frontal cirrus for the opisthe. All cirral anlagen originate in the frontal area of the proter and from parental cirri. Later, the anlagen (primary primordia) split and the proximal portions migrate posteriad forming the ventral ciliature of the opisthe. The long ventral (median) row develops from a single primordium within the central portion of the parental row. This anlage splits and proliferates basal bodies anteriad and posteriad. Dorsal kineties develop by intrakinetal proliferation; no caudal cirri are formed. Compared to other amphisiellid hypotrichs, Orthoamphisiella spp. are unique in having an apokinetal stomatogenesis and a long ventral (median) row originating from a single anlage. Further studies are needed to elucidate the phylogeny of amphisiellid hypotrichs.