Endosphaera

Endosphaera Engelmann, 1876 (ref. ID; 4338)

Endosphaera elisabetharum Guhl, 1985 (ref. ID; 4338)
Endosphaera engelmanni Entz, 1896 (ref. ID; 4338) reported author and year? (ref. ID; 191, 3689)
Endosphaera multifiliis Gonnert, 1935 (ref. ID; 4338)
Endosphaera terebrans Matthes & Guhl, 1973 (ref. ID; 4338) reported author and year? (ref. ID; 191, 3689)

Endosphaera terebrans Matthes & Guhl, 1973 (ref. ID; 4338) reported author and year? (ref. ID; 191, 3689)

Descriptions

The endocommensal stage of E. terebrans is sac-shaped and constricts at the anterior part of the cell. The endocommensal form varies in size and can measure 15-45 um long and 9-35 um wide; it has a voluminous spherical macronucleus that occupies from one-third to one-half the total volume of the cell, and a small, oval micronucleus. This species lives fixed inside the peristomial disc of the peritrich with the narrower anterior end oriented upward; the posterior rounded part is oriented down toward the posterior part of the peritrich. The infraciliature of the adult is reduced to four rows of barren kinetosomes. These four rows are constituted by 8 to 20 kinetosomes depending on the development stage and adult size. (ref. ID; 4338)

Swarmer stage: The swarmer is the free-swimming and infective stage of E. terebrans. Swarmers have a round body and possess a needle-like cellular projection. The macronucleus is round, refringent, and easily visible with light microscopy. The micronucleus is small and discoidal. Living swarmers measure 15-17.5 um, and the needle-like projection measures 7-8 um long. The swarmer has two rings of long cilia that are widely spaced surrounding the cell. The swarmer, transported by the current flow of the peritrich and by the stream of water, seems to employ cilia when free of the host ciliary whirl. The infraciliature is constituted by two rings of five to eight kinetids. The kinetids are formed by pairs of kinetosomes with two associated fibers at right angles to each other. (ref. ID; 4338)
Morphogenesis of the larva: During morphogenesis, the first sign of budding observed in E. terebrans is the proliferation at one end of two of the four kinetosome rows that constitute the adult infraciliature, resulting in two short kineties of generally five newly formed kinetosomes. The new kineties lie, at first, as a prolongation of the infraciliature of the adult and keep the same orientation. Later they migrate anteriorly and a gap is formed between both infraciliatures. The two new kineties split and separate from each other as thy move counter clockwise toward the center of the developing "brood pouch". At this point of morphogenesis, the macronuclear chromatin network has a tread-like appearance. Then the macronucleus elongates and a portion of its shifts into the swarmer-anlage. During this phase, a round mass of denser cytoplasm is observed under the infraciliature of the future larva. The kineties of the future swarmer keep migrating and finally the macronuclear division is completed. The cellular projection arises toward the posterior pole of the adult cell and, when completely formed, the larva leaves the mother cell. Once outside the host cell, the swarmer rotates pointing the projection in the same direction as the movement. Each adult cell forms one small swarmer during each budding. Before the larva completely forms, anther bud frequently forms in such a way that the parental kinetosomes already are proliferating to provide the infraciliature of a new larva. (ref. ID; 4338)
Life cycle: When the swarmer is completely formed it leaves the host cell and swims away. Soon it is attracted by the feeding current of another, or the same, peritrich. The vortex of the peritrich gives the swarmer enough impulse to penetrate the host by means of the projection. The swarmer gets inside by taking advantage of the cellular contraction of the host that occurs when the swarmer makes contact with the peristomial disc. As the swarmer begins to insert itself inside the host cell, the projection end grows blunter. Once inside the host, the swarmer turns upside down and remains in that position in the peristomial zone, close to the polykinety and the surface. Then, the swarmer matures developing the typical sac-shaped form. When the adult is completely formed, the budding process begins that culminates with the development of one migratory larva or swarmer. The swarmer leaves the host cell and infects another peritrich completing the life cycle. Normally, an adult cell produces successive larvae in consecutive buddings. In living preparations, the larvae that do not successfully infect another (or the same) host show morphological changes after awhile. They lose cilia and stop swimming, moving very slowly or not at all. The end of the needle-like projection rounds up, and the cell has an empty cap at the opposite pole. (ref. ID; 4338)