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Localization of Ciliary Primordia in Induced Abnormal Cysts of Oxytricha. fallax
Author(s) -
Hashimoto Kaneji
Publication year - 1964
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1964.tb01722.x
Subject(s) - anatomy , cyst , primordium , biology , ellipsoid , geology , pathology , medicine , gene , biochemistry , geodesy
SYNOPSIS. Precystic organisms embedded in agar become abnormal cysts. Some of them are excystable rod‐like or ellipsoid forms and the others, non‐excystable fiat ones. Major axis of the rod‐like or ellipsoid cysts is parallel with the body axis of the previous precystic organisms, because when the cysts are formed the protoplast within the secreted cyst walls rotates or agitates slightly around the major axis but movement around the minor axis is precluded. The fibrillar structures appearing in excystment from abnormal cysts are bilaterally symmetrical, different from the normal spherical cysts showing radial symmetry. The two poles from which the fibrils radiate are situated opposite each other but not at the extremities of the cyst. The locus of the anterior pole corresponds to the site of oral primordia in dividers and reorganizers. When the anterior part of the original adoral membranelles (AZM) in the early precystic animals is removed, the ellipsoid cysts from the abbreviated animals show a disturbance of the anterior fibrillar arrangement. The primoidium of the future AZM runs straight from the anterior extremity of the cyst toward the uninjured posterior pole. Ellipsoid cysts from precystic animals after the posterior region is removed similarly have disturbed fibrils near the posterior extremity of the cyst. The AZM primordium then arising on excystment extends from the uninjured anterior pole toward the damaged posterior extremity of the cyst. Similar events are found also in spherical cysts from anterior and posterior fragments of precystic animals. In either case, though the initial phase of the AZM primordium shows irregular contour, leaf‐like shape is accomplished later accompanying the increase of primordial granules, while the other ciliary primordia such as undulating membrane and cirri arise at their corresponding areas. All can produce normal excysted animals. The ciliary primordia appearing upon excystment, notably that of the AZM, therefore seem to have descended from the precystic stage or foregoing trophic one.