Architricha indica Gupta et al., 2006

Xu, Yuan, Li, Lifang, Fan, Xinpeng, Pan, Hongbo, Gu, Fukang & Al-Farraj, Saleh A., 2015, Systematic Analyses of the Genus Architricha and Pleurotricha curdsi (Ciliophora, Oxytrichidae), with Redescriptions of Their Morphology, Acta Protozoologica 54 (3), pp. 183-193 : 184-187

Architricha indica Gupta et al., 2006 ( Figs 1–4 and Table 1)

Morphological description of Shanghai population. Cells in vivo measuring 100–140 µm × 30–40 µm. Body flexible, usually elongated ellipsoid in outline ( Fig. 1A, B, H–J ). Adoral zone of membranelles (AZM) not prominent, occupying 1/4–1/3 body length, with widest part of membranelles about 15 µm ( Fig. 1A, B ). Thin Pellicle, with colorless, round cortical granules, 0.5 µm in diameter, on both ventral and dorsal sides: on ventral side, arranged in lines alongside the marginal cirral rows; and on dorsal side, spread evenly in rows ( Fig. 1C, L, M ). Several food vacuoles about 10 µm across often present ( Fig. 1A, I ). Single contractile vacuole located in equatorial region near left body margin, approximately 12 µm across, contracting at intervals of about 20 s; collecting canals undetectable ( Fig. 1H, I ). Colorless cytoplasm, usually with many lipid droplets and dumbbell-like crystals, up to 8 µm long ( Fig. 1K ). Two oval macronucleus nodules, each nodule about 10 × 6 µm in size, located at mid-body; usually two to six micronuclei, seven or eight in a few individuals ( Fig. 1E, N ). Infraciliature as shown in Fig. 1D–G, O . AZM with 28 membranelles on average. Straight and short Paroral membrane, longer endoral membrane a Data include buccal cirrus and frontoventral cirri.

gently curved underneath. Three frontal cirri and four frontal ventral cirri. Buccal cirrus located closely to the anterior end of paroral membrane. Ventral cirri in two groups: three postoral ventral cirri arranged in line just beneath the level of posterior end of AZM and two pretransverse ventral cirri located dispersedly near the end of right marginal row 1 and before the transverse cirri. Three dorsal kineties (first to third) extending over entire length of body. Fourth dorsal kinety very short and located near posterior end of body, comprising only several dikinetids. Fifth and sixth dorsal kinety occupying anterior half of body. Three caudal cirri located near posterior end of first, second, and fourth dorsal kineties.

Reorganization. Reorganization commences with the closely arranged basal bodies to form the oral primordium (OP), which occurs de novo comprising two narrow basal body groups; at the same stage, cirrus II/2 (buccal cirrus), cirrus III/2, and cirrus IV/3 disintegrate and join in the construction of frontoventral-transverse cirral anlagen II, III, and IV. Dorsal kineties begin to duplicate around the parental basal bodies ( Figs 2A , 3A, B ). Then, cirrus IV/2 disintegrates and elongates anteriorly to form anlage V, while OP begins to differentiate into membranelles when its anterior part touches the posterior end of parental adoral membranelles; paroral and endoral membranes reorganize at original locations, forming new structures ( Figs 2B , 3C ).

Morphogenesis. A detailed description of the morphogenesis was reported in the original report ( Gupta et al. 2006), thus only a brief description based on the Shanghai population is documented here.

The earliest stage observed was the presence of six frontal-mid-ventral-transverse cirral (FVT) anlagen in both opisthe and proter ( Fig. 3D ). As division progresses, six FVT anlagen keep continue developing, each dividing into fragments ( Fig. 3E ). In the following stages, the fragments migrate into relative positions and form new frontal cirri, ventral, and transverse cirri, following the typical Oxytricha pattern ( Fig. 4C–E, G). Undulating membranes of the proter derives from parental structure, and from the OP in opisthe ( Fig. 3E ). AZM of the opisthe develops anew from the OP and the proter inherits the parental one ( Figs 3D , 4E, G). In both dividers, five anlagen arise independently within five parental marginal rows and finally give birth to five new marginal rows ( Figs 3E , 4A, B, E). Dorsal kineties (DK) develop with the Oxytricha pattern. DK1–3 arise from anlagen and develop separately within parental DK1–3 ( Fig. 4F, H). The anlage of DK 3 generates an additional fragment at the posterior part, which generate DK 4 ( Fig. 4F, H). Three caudal cirri are generated at the posterior end of the new DK1, 2, and 4 ( Fig. 4H). The anlagen for dorsal kineties 5 and 6 (=dorsomarginal kineties) develop de novo near the rightmost marginal row anlage ( Fig. 4A, B, E, G).

Figures

Figs 1A–O. Line drawings and photomicrographs of Architricha indica during trophophase from life (A–C, H–M) and after protargol impregnation (D–G, N, O). A, H–J – ventral views of typical individuals, arrows in (H, I) indicate the contractile vacuole and arrowheads in (I) refer to the food vacuoles; B – different body shapes; C – distribution of cortical granules between right marginal rows; D, F – ventral view of infraciliature; E – arrangement of dorsal ciliature, caudal cirri and nuclei, arrowhead indicates the anteriorly shortened dorsal kinety 4; G, O – details of infraciliature, showing frontal cirri, buccal cirrus, frontal-ventral cirri, and postoral ventral cirri in (G), and showing pretransverse ventral cirri and transverse cirri in (O); K – detail of crystals in the cytoplasm; L, M – cortical granules on dorsal (L) and ventral (M) side; N – macronuclei and micronuclei. 1–6 – dorsal kineties 1–6, AZM – adoral zone of membranelles, BC – buccal cirrus, CC – caudal cirri, E – endoral membrane, FC – frontal cirri, FVC – frontal ventral cirri, LMR1, 2 – left marginal row 1 and 2, P – paroral membrane, PVC – postoral ventral cirri, PTVC – pretransverse ventral cirri, RMR1, 2, 3 – right marginal row 1, 2 and 3, TC – transverse cirri. Scale bars: 50 µm.

Figs 2A, B. Line drawings of protagol stained cells of Architricha indica during early stages of reorganization. A, B – ventral views, showing the formation of the oral primordium, I–V anlagen for the frontal-ventral-transverse cirri, and appearance of undulating membranes anlage, arrowheads in (B) indicate anlagen of dorsal kineties. FC – frontal cirri, FVC – frontal ventral cirri, I–V – frontoventraltransverse cirral anlagen I–V, OP – oral primordium, PVC – postoral ventral cirri, UMA – undulating membranes anlage. Scale bar: 50 μm.

Figs 3A–F. Photomicrographs of protagol stained cells of Architricha indica during regenerative (A–C) and morphogenetic stages (D–F). A, B – ventral (A) and detailed dorsal (B) view of cell during early stage of reorganization, showing the formation of oral primordium (OP), the frontoventral-transverse cirral (FVT) anlagen and dorsal kineties anlagen (arrowheads); C – anterior part of ventral side of another regenerating cell, showing the anlage V arose from the cirrus IV/2 (arrowhead); D – ventral view, showing the six streaks of FVT anlagen; E, F – ventral (E) and dorsal (F) detailed view, showing the FVT anlagen dividing into fragments, the dedifferentiation of parental undulating membranes and the origin of multiple marginal rows in (E) and showing the anlagen for dorsal kineties in (F), arrowheads showing the new frontal cirri that came from the undulating membranes anlage. DKA – dorsal kinety anlagen, FVTA – frontoventral-transverse cirral anlagen, I–V – FVT I to V, LMA – left marginal row anlagen, OP – oral primordium, RMA – right marginal anlagen, UMA – undulating membranes anlage. Scale bars: 50 μm.