Metanophrys
Metanophrys Puytorac et al., 1974 (ref. ID; 7312)
Subclass Scuticociliatia (ref. ID; 7213)
- Metanophrys diminuta Gomez-Saladin & Schaffer, 1994 (ref. ID; 7312 original paper)
- Metanophrys durchoni Puytorac et al. 1974 (ref. ID; 7312, 7561) reported author and year? (ref. ID; 191, 2085, 4006)
- Metanophrys elongata (Biggar & Wenrich, 1932) Groliere et coll., 1978 (ref. ID; 7561) reported author and year? (ref. ID; 7312, 7536)
Syn; Anophrys elongata (ref. ID; 7312)
- Metanophrys simillis (ref. ID; 7213)
Metanophrys diminuta Gomez-Saladin & Schaffer, 1994 (ref. ID; 7312 original paper)
Diagnosis
Oral polykinetid #1 (OPK 1) composed of two files of kinetosomes, micronucleus roughly spherical to ovoid, nestled in macronucleus. Oral dikinetid c (ODK c) segment composed of 3-4 pairs of kinetosomes. Cell length shorter than M. elongata and M. durchoni. (ref. ID; 7312)
Descriptions
The morphology of Metanophrys diminuta is typical of small philasterine scuticociliates (Small 1967). The ciliates possess three oral polykinetids (OPK) and one oral dikinetid (ODK). OPK 1 has 2 files of kinetosomes, OPK 2 is equal in length to, or shorter than, OPK 1. OPK 2 has 3-5 files of kinetosomes. OPK 3 is triangular to diamond shaped. ODK c segment is a single file of 3-4 pairs of kinetosomes aligned along the mid ventral post oral region. The first pair of kinetosomes of ODK c segment is oriented at 45-90 degrees angle to kinety n (kinety adjacent to the ODK). Cell length 27.1 um+/-3.7 (range 21-36.6 um, n=30). Cell width 10.5 um+/-1.9 (range 7.4-14.9, n=30). Nine to twelve kineties spiraled slightly around the cell (n=30). Somatic kineties were primarily (60%) composed of single kinetosome kinetids. Paired kinetosomes, usually found towards the anterior half of the cell, occurred in 27% of the population. Ten percent of the kineties were comprised of dikinetids.
The centrally located macronucleus is roughly spherical with an average length of 5.3 um+/-0.92 (range 4.0-6.9 um, n=30) and an average width of 4.8 um+/-1.0 (range 3.0-6.9, n=30) and the micronucleus is embedded in the macronucleus. Numerous lipid droplets can be observed in the cytoplasm and mitochondrial profiles are located mainly near the periphery of the organism.
The very prominent micronucleus is elliptical or ovoid in shape, with a average length of 1.8 um+/-0.6 (range 1.0-3.0 um, n=30). Most of the heterochromatin concentrated towards the center, as observed both in light and electron microscopy. An electron-translucent area surrounds the heterochromatin. Most micronuclei (90%, n=50) are nestled at the anterior edge of the macronucleus, but only occasionally are they removed from the macronucleus (8%), or nestled at the posterior edge of the macronucleus (2%). Nucleoli are mostly distributed adjacent to the inner nuclear membrane of the macronucleus. Several nuclear pores were observed on both nuclear envelopes. Membrane continuity was not clearly observed between macronucleus and micronucleus.
Mitochondria were observed mainly near the periphery of the organism, between kineties. Longitudinal profiles were estimated to be approximately 25-30 um long (or almost the entire length of the cell). Interlocking mitochondria were also observed. Curious mitochondrial fenestrations (or deep pockets) traverse the mitochondria and contain cytoplasm. Rough endoplasmic reticulum (RER) profiles were observed in close association with the proximal side of mitochondria. RER profiles were also observed within mitochondrial fenestrations (or deep pockets).
Both somatic monokinetids and dikinetids were observed. Connecting fibers were observed between anterior and posterior kinetosomes of a dikinetid and the origin of the kinetodesmal fiber was located to the posterior kinetosome. The somatic monokinetids included divergently oriented post ciliary MT ribbon (PC), kinetodesmal fiber oriented anteriorly and to the right, and tangentially oriented transverse MT riboon. The same structures were observed in association with the posterior kinetosome of somatic dikinetids. However, TMT were not oberved in association with the anterior kinetosome of a somatic dikinetid.
Oral kinetids were also observed. The oral dikinetids have a zig-zag configulation with post ciliary MT ribbons extending from the posterior kinetosome of each dikinetid. Oral polykinetids were also observed in a gap between mitochondrial profiles on the ventral surface towards the anterior end. (ref. ID; 7312)
Remarks
Light microscopic observations provided evidence to support placement of this strain in a new species in the genus Metanophrys. M. diminuta is smaller than either M. elongata (Groliere et al. 1980) (which is >100 um long) or M. durchoni (Puytorac et al. 1974) (55 um long). Even after taking into account shrinkage due to the QPS strain (Montagnes & Lynn 1987), the estimated live cell length of M. diminuta is only 35 um. The number of kineties (9-12) is less than that of M. elongata (15-20), but includes the value for M. durchoni (11). The shape of ODK c segment of M. diminuta is a straight line except the first pair of kinetosomes, which is positioned at an angle. The ODK c segment of M. durchoni is "V" shaped, composed of single kinetosomes (Puytorac et al. 1974) and the ODK c segment of M. elongata is a straight line composed of single kinetosomes (Groliere et al. 1980).
The ultrastructure of the somatic dikinetid pattern of M. diminuta strain 34-7 described herein supports placement in the class Oligohymenphorea and is similar to dikinetid patterns observed in other scuticociliates. A transverse MT (TMT) ribbon has not been observed on the anterior kinetosomes of several philasterine and pleuronematine scuticociliates, such as Conchopthirus, Cohnilembus, Cinetochilum (Lynn 1981; Lynn & Corliss 1991), Parauronema (Rodrigues de Santa Rosa & Puytorac 1976) and Porpostoma (Coats 1977). However, tangentially oriented TMT ribbons have been observed proximal to the anterior kinetosomes of Anophryoides (Puytorac & Groliere 1979), Paranophrys thompsoni, Dexiotricha (Lynn 1981), and Cyclidium (Blacker 1975). The transverse fibrous spur has not been observed in TEM studies of M. diminuta thus far, but is present (althoguh highly variable in the extent of its development) in the aforementioned scuticociliates.
Other organelles associated with the somatic dikinetid of M. diminuta are typical of oligohymenophoreans, such as the divergent post-ciliary microtubular ribbon, anteriorly-directed KD fiber, and the radially oriented transverse MT ribbon originating from the posterior kinetosome.
Other characteristics of the ultrastructure of this ciliate were also observed, such as the appearance of mitochondria and nuclei. Mitochondrial profiles are very long and peripheral, suggesting that this organism may well possess a single mitochondriome, similar to the uronematid reported by Kaneshiro & Holz (1976). However, not enough evidence was obtained to support this idea. In any case, long mitochondrial profiles have been observed in uronematids (Kaneshiro & Holz 1976), Philaster digitiformis (Puytorac et al. 1966) and Conchopthirus curtus (Antipa 1971). Mitochondrial fenestrations (or deep pockets) may serve to increase surface area, and thus interaction with the cytoplasm in general, and specifically with RER, which was observed both surrounding mitochondria and within fenestration.
Like the micronuclei of other scuticociliates and hymenostomes, the micronucleus of M. diminuta lies in an indentation of the macronuclear envelope. Unlike the micronuclei of uronematids (Kaneshiro & Holz 1976) and some tetrahymenines (Elliot & Kennedy 1973), the micronucleus of M. diminuta is ovoid. In the case of uronematids, membrane continuity was observed between micronucleus and macronucleus. In an even more extreme case, the micronucleus of Woodruffia metabolica was shown to lie between the outer and inner nuclear membranes of the macronucleus (Golder 1976). Although many sections were examined, no clear connection was evident between the micronucleus and macronucleus of M. diminuta, but the abundance of nuclear pores on both nuclear envelopes, especially near the internuclear space, probably provides ample opportunity for exchange of macromolecules between nuclei.
In summary, the ultrastructure of Metanophyrs diminuta reveals: somatic kinetid which are consistent with other scuticociliates; morphology of mitochondria, similar in length and distribution to other scuticociliates but with unusual fenestrations (or deep pockets); and morphology of the nuclear apparatus, which is comparable to other scuticociliates and hymenostomatids. (ref. ID; 7312)
Etymology
Specific name refers to the small size of this species relative to M. elongata and M. durchoni. (ref. ID; 7312)
Type location
Miami, Florida inland coastal waters. (ref. ID; 7312)
Type specimens
Two slides containing the holotype (USNM# 43207) and paratypes (USNM# 43208) were deposited at the National Museum of Natural History. (ref. ID; 7312)
Metanophrys durchoni Puytorac et al. 1974 (ref. ID; 7312, 7561) reported author and year? (ref. ID; 191, 2085, 4006)
Type locality
This species found in the coelum of the polychaete Nereis diversicolor (Puytorac et al. 1974). (ref. ID; 7312)
Metanophrys elongata (Biggar & Wenrich, 1932) Groliere et coll., 1978 (ref. ID; 7561) reported author and year? (ref. ID; 7312, 7536)
Synonym
Anophrys elongata (ref. ID; 7312)
Remarks
The species was redescribed in 1980 by Groliere et al. from samples obtained from the gastric cavity of several echinoderms. (ref. ID; 7312)
Descriptions
Analysis of the internal transcribed spacer 2 (ITS2) region. (ref. ID; 7213)