Cap 15
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Cap 15


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of some oligohymenophoreans 
may also contain phosphatases (Lobo da Cunha & 
Azevedo, 1990). 
 As in other ciliates, the alveoli are underlain by 
an epiplasmic layer (Allen, 1967, 1971). The epi-
plasm of hymenostomes includes some of the same 
proteins as found in other protists \u2013 the multigene 
families of articulins and epiplasmins (Huttenlauch 
& Stick, 2003; Huttenlauch, Peck, & Stick, 1998; 
Pomel et al., 2006). Differential extraction tech-
niques demonstrated that this layer, isolated as 
a ghost cell, provides a cortical scaffold for the 
cell (Collins, Baker, Wilhelm, & Olmsted, 1980; 
Keryer et al., 1990). On one hand, the varieties of 
cortical proteins in related Tetrahymena species are 
vastly different, and yet the form of these cells is 
very similar (Williams, 1984). On the other hand, 
the microstome and macrostome phenotypes of 
T. vorax , which are morphologically dramatically 
different, show very similar profiles of cortical pro-
teins (Buhse & Williams, 1982). Nevertheless, Keryer 
et al. (1990) demonstrated the over-abundance 
of a particular band in one cortical mutant of 
Paramecium . Thus, a molecular change in a sin-
gle component can have dramatic morphological 
effects. This has now been confirmed also for 
Tetrahymena : knockout constructs of the cortical 
protein Epc1p have altered cell shape (Williams, 
2004). How these very different molecules can 
assemble similarly- or differently-shaped cells 
remains to be explained. 
 In peritrichs , the epiplasm is often quite thick on 
the non-ciliated body surface, and it is penetrated 
by pores that are presumably homologues of the 
 parasomal sacs of other oligohymenophoreans 
(Lom, 1994). In scuticociliates and hymenostomes , 
there are one to many supraepiplasmic micro-
tubules , called longitudinal microtubules , which 
extend the length of the cell (Allen, 1967; Antipa, 
1972; Peck, 1977a). Presumed homologues of these 
microtubules appear transiently during division of 
 peniculines (Sundararaman & Hanson, 1976). 
 The most prominent features of the ciliate cor-
tex, the cilia associated with the somatic kinetids , 
have been extensively studied in Tetrahymena
and Paramecium . Freeze-fracture analyses dem-
onstrated that the somatic cilia have few randomly 
distributed particles over most of their length. 
However, at the base, distal to the ciliary neck-
lace , were nine plaques of three longitudinal rows 
of particles at the ciliary base (Plattner, 1975; 
Sattler & Staehelin, 1974). These plaques are 
associated with Ca 2+ \u2212binding sites and are linked 
via an internal plaque complex to the peripheral 
doublets of the ciliary axoneme (Dute & Kung, 
1978; Plattner). Ca 2+ and cyclic nucleotides affect 
ciliary movement, and so influence the behavioral 
responses of oligohymenophoreans (Machemer & 
Sugino, 1989; Noguchi, Kurahashi, Kamachi, & 
Inoue, 2004). Parasomal sacs are associated with 
the base of the cilium. These sacs are regions of 
 pinocytosis as cationized ferritin is internalized 
by them (Nilsson & Van Deurs, 1983). Moreover, 
there is suggestive evidence that they may also be 
a route for the exocytosis of certain enzymes (Allen 
& Fok, 2000; Nielsen & Villadsen, 1985). 
 The somatic kinetid of oligohymenophoreans 
has been characterized as a monokinetid as follows: 
a divergent, well-developed postciliary ribbon that 
extends usually to the next kinetid in the kinety but 
not to overlap its postciliary ribbon; a well-
 developed, anteriorly-directed kinetodesmal fibril 
that originates near triplets 5\u20137 and tapers as it 
overlaps fibrils from other kinetids; a reduced to 
well-developed, radially-oriented transverse rib-
bon that extends typically from triplet 4 laterally 
towards the adjacent kinety; and, in some cases, 
a transverse fibre that originates near triplet 3 and 
extends laterally in association with the trans-
verse ribbon (Figs. 15.6\u201315.9) (Lynn, 1981, 1991). 
Dikinetids, often in the anterior part of the cell, 
have similar fibrillar associates to the monoki-
netid, but the anterior kinetosome usually bears 
a tangential transverse ribbon (Figs 15.6\u201315.8) 
(Lynn, 1981). While the monokinetid description 
applies very well to the kinetids of scuticociliates , 
 hymenostomes , apostomes , and some astomes , the 
kinetids of peniculines , predominantly dikinetids, 
differ in that both sets of transverse ribbons are 
tangential to the perimeter of the kinetosome (Fig. 
15.6) (Lynn, 1981, 1991). Somatic kinetids of peri-
trichs are so highly modified that there are really 
no obvious similarities ( see below ). Extending 
the length of the kineties, near the base of the 
kinetosomes, are several basal microtubules that 
may supply additional structural support to the 
cortex (Allen, 1967; Antipa, 1972). In peniculines , 
somatic kinetids can be connected by filamentous 
bands at mid-kinetosome level while their bases 
are surrounded by a complex network of filaments, 
called the infraciliary lattice (Allen, 1971). This 
lattice does have contractile properties and demon-
strates cross-reaction to antibodies that recognize 
the filamentous layer of the litostomes (Garreau 
de Loubresse, Keryer, Viguès, & Beisson, 1988). 
Antipa (1972) carefully described structural dif-
ferentiation of somatic kinetids in the cortex of 
the scuticociliate Conchophthirius : the kinetids in 
the thigmotactic region of the cortex of this ciliate 
were modified compared to those of the locomo-
tory cortex. 
 Since the reviews of Lynn (1981, 1991) and Grain 
(1984), there have been relatively few reports of 
the ultrastructure of oligohymenophorean kinetids. 
Those that have appeared have confirmed these basic 
patterns. Some selected older and recent references 
are: for peniculines \u2013 Paramecium (Allen, 1971); 
Frontonia , Urocentrum (Didier, 1971); for the scu-
ticociliates \u2013 Cinetochilum (de Puytorac, Didier, 
Detcheva, & Grolière, 1974a), Conchophthirus
(Antipa, 1972); Dexiotricha (Peck, 1977a); 
Myxophthirus (Da Silva Neto, 1992), Paranophrys
(Didier & Wilbert, 1976), Proboveria (de Puytorac, 
Grain, Grolière, & Lopez-Ochoterena, 1978); 
for hymenostomes \u2013 Colpidium (Lynn & Didier, 
15.3 Somatic Structures 303
304 15. Subphylum 2. INTRAMACRONUCLEATA: Class 9. OLIGOHYMENOPHOREA
1978), Glaucoma (Peck, 1978), Ichthyophthirius
(Chapman & Kern, 1983), Turaniella (Iftode et 
al., 1984); for apostomes \u2013 Hyalophysa (Bradbury, 
1966b), Collinia (de Puytorac & Grain, 1975); for 
 astomes \u2013 Coelophrya , Dicoelophyra (Grain & de 
Puytorac, 1974). Undoubtedly the most unusual 
 oligohymenophorean somatic kinetid is that of the 
 scuticociliate Schizocaryum , whose somatic cortex 
is covered by cirrus-like polykinetids \u201corganized\u201d 
adjacent to a typical oligohymenophorean monoki-
netid (Fig. 15.9) (Lynn & Frombach, 1987). 
 The vast majority of sessiline peritrich species 
only display somatic ciliature at the time of cell 
division or when stimulated to leave their stalk by 
adverse environmental circumstances (Barlow & 
Finley, 1976; Rose & Finley, 1976). At this time, 
the daughter zooid or telotroch differentiates a 
band of cilia, called the trochal band , at the pole 
opposite the oral region, composed of from one 
row in Lagenophrys up to eight rows in Ophrydium
(Fig. 15.3) (Lom, 1994). The trochal band of ses-
siline peritrichs , such as Opisthonecta , which are 
permanently motile, can be a complex arrangement 
of ciliated kinetosomes. The fibrillar associates 
and arrangement provide no evidence of homol-
ogy with the somatic kinetids of other oligohy-
menophoreans (Bradbury, 1965). The trochal band 
surrounds the scopula , a structure at the extreme 
aboral pole, which includes kinetosomes with 
modified and reduced cilia, microtubular rootlets 
extending into the cytoplasm, and secretory gran-
ules (Fauré-Fremiet, 1984; Lom & Corliss, 1968; 
Willey