Spiromonas

1. Spiromonas akopos Skuja, 1939
   See; Cryptaulax sp. (ref. ID; 4907)
2. Spiromonas augusta (Dujardin) (ref. ID; 1618) or (Dujardin) Alex. (ref. ID; 4656) reported author and year? (ref. ID; 7739)
   See; Bodo edax Klebs (ref. ID; 4656)
3. Spiromonas gonderi Wilhelm Foissner & Ilse Foissner, 1984 (ref. ID; 7739 original paper)
4. Spiromonas perforans (ref. ID; 7739)

Spiromonas augusta (Dujardin) (ref. ID; 1618) or (Dujardin) Alex. (ref. ID; 4656) reported author and year? (ref. ID; 7739)

See

Descriptions

Measurements

Spiromonas gonderi Wilhelm Foissner & Ilse Foissner, 1984 (ref. ID; 7739 original paper)

Diagnosis

Descriptions

• Light microscopy: Freely moving, not parasitizing individuals are egg-shaped, with the more pointed end anterior and the more rounded end posterior; size ca. 5-7x4-6 um. Well-nourished parasitizing individuals are nearly spherical, measuring up to 10-12x8-10 um, with circular cross section. Flagella about equal in lenght with insertion clearly subpolar; they beat vigorously but cause only a trembling, nearly undirected movement of the animal. Those of parasitizing individuals are extended backward, usually so as to form a figure-eight. Nucleus approximately in the middle of the body, with a large central nucleus. The cytoplasm of free individuals and young parasites contains only a few minute granules, whereas older parasitizing individuals always have one large spherical to kidney-shaped inclusion at the posterior end. The latter is impregnated like the nucleus with protargol silver. No contractile vacules were seen, either in vivo or in the electron microscope. (ref. ID; 7739)
• Electron microscopy: All the electon-microscopic data presented here are based on attached individuals parasitizing Colpoda fastigata or Paracolpoda steinii. Unfortunately, we found no free parasites. (ref. ID; 7739)
  • Flagella and the associated fibrils. The flagella and their basal bodies have few unusual features. At the level of the rather large axosome the flagella are distinctly constricted. The proximal part of the left flagellum is seated in a periflagellar canal, closed at the proximal part and at the distal one tapering out as a shallow groove open ventrally. Its basal body is located ca. 0.5 um further anterior than that of the right flagellum, which arises directly from the cell surface. The basal bodies are arranged approximately in parallel with the ventral surface, form roughly a right angle with one another and are joined proximally by a microfibrillar, cross-striated desmose measuring ca. 400x80 nm. From the left basal body 2 fibril systems, presumably consisting of microtubules, extend to the level of the nucleus. System 1 arises near the interkinetosomal desmose and runs along tightly underneath the pellicle. System 2 arises at the left edge of the basal body and runs along the dorsal wall of the periflagellar canal. (ref. ID; 7739)
  • Pellicle. The pellicle is ca. 25-30 nm thick and consists of 3 unit membranes. The outer membrane covers the whole animal, including the flagella, as a continuous sheet. The two inner membranes, which are very closely apposed and difficult to resolve, are absent in the tubular part of the periflagellar canal, at the micropores, and perhaps also in other small regions of the cell. Often one has the impression that they form flat alveoli, or that the inner-most membrane is lacking in certain areas. At many places in the pellicle there are tubular or saclike invaginations of the outer cell membrane; we follow Brugerolle and Mignot (1979) in calling these "micropores". In cross section they have a bright lumen ca. 30-40 nm in diameter, surrounded by a ring of very electron-dense material about equal in width. The diameter of the entire organelle is thus ca. 100 nm. Just below the pellicle lie microtubules in a fairly regular arrangement; they begin at the level of the fixation apparatus and extend about to the middle of the body - some, perhaps, as far as the posterior end. They appear to have a slightly spiral arrangement. In almost all parasites the pellicular surface is covered by a netlike fibro-granular structure 50-100 nm thick. This surface coat is absent only in the region of the periflagellar canal and the fixation apparatus. (ref. ID; 7739)
  • Fixation apparatus. At the edge of the conically expanded zone where host and parasite are joined there are 4-5 (average=4.6, n=8) microtubules in an annular (perhaps spiral) arrangement. We could not determine whether this ring is formed of several specialized subpellicular microtubules curved at their anterior ends or whether it is an independent structure. The first interpretation is supported by sections in which both the microtubules of the ring and those of the body are cut in the same direction, longitudinally or across. The second possibility is supported by pictures in which the microtubules of the ring are cut across, and those of the body longitudinally or oblique. Above the ring there is a small, empty zone bounded by a unit membrane ca. 10 nm thick, which separates host and parasite. This separating membrane is formed in a remarkable manner: near the outermost microtubules of the ring the inner electron-dense layer of the outer cell membrane of the ciliate fuses with that of the flagellate. We do not known whether the membrane seal is new formation or whether the original membranes of host and parasite contribute to some extend. The two inner membranes of the pellicle of the flagellate are usually joined to the outermost microtubule of the ring, appearing slightly more dense in this region. The resulting picture resembles the polar ring of the Coccidia (cf. Scholtyseck 1979; Russell and Burns 1984). The membrane-bounded alveoli of the ciliate end in the vicinity of the separating membrane. (ref. ID; 7739)
  • Cytoplasmic organelles. In the anterior region of the parasite, chiefly in the vicinity of the periflagellar canal, there are many membrane-bounded, electron-dense ampulla-shaped organelles; we adopt the term "micrineme" for these, as proposed by Brugerolle and Mignot (1979). Their thin, tubular endings usually point in the direction of the host. The micronemes are up to 1000 nm long, and their thickness is ca. 24 nm anteriorly and up to 120 nm posteriorly. In cross section they are circular, with a more electorn-dense area in the center. The cytoplasm of the parasite is frequently less electron-dense than that of the host. It contains many ribosomes, which often from dense aggregations in the form of an irregular sphere up to 200 nm in diameter. The cisternae of the endoplasmic reticulum are usually rather indistinct; they tend to be just below the pellicle and are most abundant in the anterior region. The Golgi apparatus is always very difficult to discern. There are probably 2 dictyosomes approximately at right angle to one another near the nucleus, each composed of a few thin cisternae.
  • The nucleus has not special features. In most of the preparations the section passes through many mitochondria. Some series, though incomplete, indicate that these are part of a single, highly branched, netlike giant mitochondrion. The cristae are tubular to vesicular, very irregularly distributed, and sometimes constricted at the base. The matrix is brighter than that of the host's mitochondria. The cytoplasm also contains the following inclusions: (i) Membrane-bounded vesicles up to ca. 800 nm in diameter, which in general are clear though sometimes they contain several small, very electron-dense spheres. (ii) Membrane-bounded vesicles up to 1000 nm in diameter, moderately electron-dense, which presumably contain polysaccharides in as much as they closely resemble those of S. perforans (Brugerolle and Mignot 1979). (iii) Irregularly spherical lamellar bodies up to 1200 nm in diameter, which appear to be constructed of concentric membranes. These are found only in individuals that have been parasitizing for some time. They could be lipid bodies in the process of formation (Wanner and Kost 1984). (iv) A spherical to kidney-shaped inclusions in the posterior part of the body, up to 8000 nm in size, which could also be identified in the light microscope. It is especially well developd in older individuals that have been parasitizing for a long time and may well contain reserve substances or excreta, as its finely granular structure indicates. It is enclosed in two unit membranes and has a central more electron-dense region in the form of an irregular sphere. Here and in the brighter periphery are scattered membrane-bounded vesicles with undefinable content. (ref. ID; 7739)
  • Reactions of the host. The parasite destroys the host's pellicle at the site of attachment. In some sections the cytoplasm of the ciliate near the separating membrane contains large numbers of small, apparently empty vacuoles. Probably these eventually fuse to produce the striking vacuolation, visible even in the light microscope, of the cytoplasm of a heavily infested host. In caes of severe infestation cytoplasm is stained remarkably deep black after protargol impregnation, and few or no extrusomes (mucocysts) remain. Apart from these, the host exhibits no conspicuous changes. Its mitochondria and subpellicuar microtubules, often closely apposed to the separating membrane, are normal in structure and unaltered in their staining behavior. (ref. ID; 7739)

Notes

Hosts

Type location

Type specimens