Redescription of flagellar arrangement in the duck intestinal flagellate, Cochlosoma anatis and description of a new species, Cochlosoma soricis n. sp. from shrews

Cochlosoma anatis Kotlán (Zoomastigophorea, Retortamonadida, Cochlosomidae), isolated from the large intestines of domestic Rouen ducks, and Cochlosoma soricis n. sp., isolated from the small intestines of shrews, were observed by light and scanning electron microscopy. In both organisms, a single flagellum inserted on the dorsal surface at the same level as the insertion of 4 other flagella on the ventral surface. The 4 ventro-lateral flagella emerged from the left side of the anterior attachment disk below the margin and just above the lateral groove which extended the length of the organism. A 6th flagellum emerged from the margin of the attachment disk. The proximal ends of the flagella formed a bundle with the distal ends becoming unraveled like a rope. During motility, the bundle portion extended straight out from the cell and the free ends of the flagella produced a whipping motion. In C. anatis, the dorsal surface was covered with knob-like lumps and small pits and the cells had an axostyle that emerged slightly to the right of the midline in the posterior 1/3 of the body. The axostylar tip was shorter and thicker than the flagella and in most cells it also had an irregular, knobby appearance. The irregular cell surface and axostyle were absent from C. soricis. The margin of the attachment disk curved toward the center and terminated in C. anatis as a straight edge while in C. soricis it continued as a spiral. Indentations in the mucosal brush border similar to those produced by Giardia, but distinctly belonging to Cochlosoma, were interpreted as points of attachment to the host.     

Coordinated Flagellar and Ciliary Beating in the Protozoon Tritrichomonas foetus1

ABSTRACT. Tritrichomonas foetus is a flagellated protozoon found in urogenital tract of cattle. Its free movement in liquid medium is powered by the coordinated movement of three flagella projecting towards the anterior region of the cell, and one recurrent flagellum that forms a junction with the cell body and ends as a free projection in the posterior region of the cell. We have used video microscopy and digital image processing to analyze the relationships between the movements of these flagella. The anterior flagella beat in a ciliary type pattern displaying effective and recovery strokes, while the recurrent flagellum beats in a typical flagellar wave form. One of the three anterior flagella has a distinctive pattern of beating. It beats straight in its forward direction as opposed to the ample beats performed by the others. Frequency measurements obtained from cells swimming in a viscous medium shows that the beating frequency of the recurrent flagelium is approximate twice the frequency for the three anterior flagella. We also observed that the costa and the axostyle do not show any active motion. On the contrary, they form a cytoskeletal base for the anchoring and orientation of the flagella.     

Cochlosoma Infection in a Turkey in Iran

Cochlosoma sp. infection was identified in a single case among 60 stunted diarrheic native turkey poults, Meleagris galopavo. A large number of the flagellated parasites was found free or within the intervillous spaces of the jejunum, ileum and cecum. Moderate enteritis was associated with the parasites. In TEM studies of the parasagittal sections of the parasite, a prominent ventral sucker like disc and flagella emerging from an opening on the ventrodorsal surface of the pyriform uninuclear parasite were found. The morphological characteristics of this protozoan match with those described for Cochlosoma anatis. The parasite could be considered as an intestinal pathogenic protozoan causing stunting and diarrhea in turkeys in Iran.     

Morphological Differences in Flagella in Campylobacter fetus Subsp. intestinalis and C. fetus Subsp. jejuni

Intact flagella were isolated from human pathogenic strains of Campylobacter, C. fetus subsp. intestinalis and C. fetus subsp. jejuni, by the method of DePamphilis and Adler and examined by electron microscopy. The isolated flagella were composed of a filament, a hook, a basal body, and a large disk associated with the end of the hook region covering the basal body. The width of the hook was approximately 28 nm, somewhat greater than that of the filament (20 nm in diameter). The hook region of C. fetus subsp. intestinalis was curved, but it was straight in C. fetus subsp. jejuni. The structure of the basal body of the two subspecies was similar to that reported for other gram-negative bacteria. The large disk detached from the flagella showed concentrically arranged circular structures. This structure was more clearly observed in the disk of C. fetus subsp. jejuni than in C. fetus subsp. intestinalis. Observations of thin-sectioned profiles at the attachment site of the flagellum revealed that the large disk is located on the inner side of the outer membrane. The role of the large disk in bacterial movement is not clear, but it is assumed that it acts as an organ to protect the flagellar insertion site from vigorous rotation of the polar end inflicted during bacterial movement.     

Transition of bacterial flagella from helical to straight forms with different subunit arrangements.

We have found that several kinds of helical flagella from Salmonella and Escherichia become straight in the presence of 0·5 m-citric acid at pH values below 4·0, while the straight flagella from a mutant Salmonella (SJ814) are transformed into a helical shape under the same conditions. These transformations are reversible and transitional.Current models of bacterial flagella (Calladine, 1976,1978; Kamiya, 1976) predict that the family of distinct wave-forms should include two types of straight flagella, which have either an extreme right-handed twist (about 7 ° at the surface of the flagellum) or an extreme left-handed twist (2 ° to 3 °). As the inclination of the near-longitudinal rows of subunits in the Salmonella SJ814 flagellum (O'Brien &; Bennett, 1972) agrees closely with the degree of twisting predicted for the right-handed type, this flagellum has been considered to be the right-handed type. We have determined that the basic (1-start) helix in flagella is right-handed, using the method of Finch (1972). This fact, together with the selection rule (O'Brien &; Bennett, 1972), strongly suggests that the near-longitudinal rows in an SJ814 flagellum are right-handed, in agreement with the prediction. However, our optical diffraction and X-ray diffraction studies have revealed that the near-longitudinal rows of subunits in the citric acid-induced straight flagella and in the straight flagella from a mutant E. coli (Kondoh &; Yanagida, 1975) tilt at an angle of 2 ° to 3 ° with respect to the flagellar axis. This inclination is probably left-handed. Thus the predicted presence of the two types of straight flagella seems to be proved.     

An immunofluorescent study of the microtubule organization in Trichomonas vaginalis using antitubulin antibodies

The flagellated protozoon Trichomonas vaginalis, parasite of the human urogenital tract, possesses a well developed microtubule system organized in highly differentiated structures. We have shown by immunoblotting that monospecific anti-sheep brain tubulin antibodies are able to react with the microtubular tubulin of T. vaginalis. These antibodies were used to study the microtubular system of T. vaginalis both in interphase and mitosis by indirect immunofluorescence. The interphase microtubular pattern, characterized by an axostyle, a pelta, four anterior flagella, and a recurrent flagellum, displayed remarkable changes at the onset of mitosis: the axostyle disappeared, and two pole bodies connected by a short spindle became evident; chromosomal fibers arose while pole-to-pole fibers elongated. The last phases of mitosis were marked by the disappearance of chromosomal fibers, the appearance of two small axostyles, and the depolymerization of the pole-to-pole bundle. At the end of mitosis, the normal interphase microtubule pattern was observed.     

Fine-Structural Changes Associated with Pseudocyst Formation in Trichomitus batrachorum*

SYNOPSIS. Several fine-structural changes were observed during formation of the so-called pseudocysts of Trichomitus batrachorum grown in an agar-free medium. Among these changes the most frequent were those of the undulating membrane complex. Internalization of the marginal lamella combined with disappearance of the fin-like, membranous dorsal fold occurred with the highest frequency. In many organisms these alterations were accompanied by internalization of the recurrent flagellum, which, however, remained external in other, presumably earlier stages of pseudocyst formation. In some of the internalized and even still external recurrent flagella the microtubules were in various states of disassembly. The often distended flagellar membrane enclosed large accumulations of filaments 5 nm in diameter. Internalization of the anterior flagella also was noted. Changes similar to those characteristic of the recurrent flagella were not seen, however, among the microtubules of the anterior flagella or among those of the pelta or the axostyle.     

An Immunofluorescent Study of the Microtubule Organization in Trichomonas vaginalis Using Antitubulin Antibodies1

ABSTRACT. The flagellated protozoon Trichomonas vaginalis, parasite of the human urogenital tract, possesses a well developed microtubule system organized in highly differentiated structures. We have shown by immunoblotting that monospecific anti-sheep brain tubulin antibodies are able to react with the microtubular tubulin of T. vaginalis. These antibodies were used to study the microtubular system of T. vaginalis both in interphase and mitosis by indirect immunofluorescence. The interphase microtubular pattern, characterized by an axostyle, a pelta, four anterior flagella, and a recurrent flagellum, displayed remarkable changes at the onset of mitosis: the axostyle disappeared, and two pole bodies connected by a short spindle became evident; chromosomal fibers arose while pole-to-pole fibers elongated. The last phases of mitosis were marked by the disappearance of chromosomal fibers, the appearance of two small axostyles, and the depolymerization of the pole-to-pole bundle. At the end of mitosis, the normal interphase microtubule pattern was observed.     

Cthulhu Macrofasciculumque n. g., n. sp. and Cthylla Microfasciculumque n. g., n. sp., a Newly Identified Lineage of Parabasalian Termite Symbionts

The parabasalian symbionts of lower termite hindgut communities are well-known for their large size and structural complexity. The most complex forms evolved multiple times independently from smaller and simpler flagellates, but we know little of the diversity of these small flagellates or their phylogenetic relationships to more complex lineages. To understand the true diversity of Parabasalia and how their unique cellular complexity arose, more data from smaller and simpler flagellates are needed. Here, we describe two new genera of small-to-intermediate size and complexity, represented by the type species Cthulhu macrofasciculumque and Cthylla microfasciculumque from Prorhinotermes simplex and Reticulitermes virginicus, respectively (both hosts confirmed by DNA barcoding). Both genera have a single anterior nucleus embeded in a robust protruding axostyle, and an anterior bundle flagella (and likely a single posterior flagellum) that emerge slightly subanteriorly and have a distinctive beat pattern. Cthulhu is relatively large and has a distinctive bundle of over 20 flagella whereas Cthylla is smaller, has only 5 anterior flagella and closely resembles several other parababsalian genera. Molecular phylogenies based on small subunit ribosomal RNA (SSU rRNA) show both genera are related to previously unidentified environmental sequences from other termites (possibly from members of the Tricercomitidae), which all branch as sisters to the Hexamastigitae. Altogether, Cthulhu likely represents another independent origin of relatively high cellular complexity within parabasalia, and points to the need for molecular characterization of other key taxa, such as Tricercomitus.     

Tritrichomonas mobilensis n. sp. (Zoomastigophorea: Trichomonadida) from the Bolivian squirrel monkey Saimiri boliviensis boliviensis

A trichomonad flagellate, Tritrichomonas mobilensis n. sp., is described from the large intestine of the squirrel monkey, Saimiri boliviensis boliviensis. The organism has a lanceolate body 7-10.5 micrometers in length; a well developed undulating membrane; a stout, tubular axostyle with periaxostylar rings that terminate in a cone-shaped segment projecting from the posterior end of the cell; and a moderately wide costa. The anterior flagella are about as long as the body, and the recurrent flagellum is of the acroneme type. All its characteristics suggest that the new species belongs in the Tritrichomonas augusta type of the subfamily Tritrichomonadinae.     

Basal body positioning is controlled by flagellum formation in Trypanosoma brucei

To perform their multiple functions, cilia and flagella are precisely positioned at the cell surface by mechanisms that remain poorly understood. The protist Trypanosoma brucei possesses a single flagellum that adheres to the cell body where a specific cytoskeletal structure is localised, the flagellum attachment zone (FAZ). Trypanosomes build a new flagellum whose distal tip is connected to the side of the old flagellum by a discrete structure, the flagella connector. During this process, the basal body of the new flagellum migrates towards the posterior end of the cell. We show that separate inhibition of flagellum assembly, base-to-tip motility or flagella connection leads to reduced basal body migration, demonstrating that the flagellum contributes to its own positioning. We propose a model where pressure applied by movements of the growing new flagellum on the flagella connector leads to a reacting force that in turn contributes to migration of the basal body at the proximal end of the flagellum.     

Reconstruction of the flagellar apparatus in Ploeotia costata (Euglenozoa) and its relationship to other euglenoid flagellar apparatuses

The flagellar apparatus of Ploeotia costata Farmer and Triemer was reconstructed using serial sectioning and TEM. The flagellar apparatus is similar to other euglenoids having two flagella arising from basal bodies connected by a striated fiber, and three asymmetrically arranged roots. The flagella emerge subapically from between the two ventral pellicle strips. The dorsal flagellum is 1/2 the body length and actively pulls the cell, while the ventral flagellum is twice the body length and drags along the substrate surface. The ventral and dorsal roots are on the opposite sides of their respective basal bodies, while the intermediate root is associated with the ventral flagellum on the side closest to the dorsal basal body. The dorsal root lines the dorsal side of the reservoir and after giving rise to the dorsal band lines the right side of the reservoir/canal. The ventral and intermediate roots join at the reservoir forming the intermediate-ventral root, which lines the left and ventral sides of the reservoir/canal. There was no evidence of a microtubule-reinforced pocket in P. costata. Comparisons with Ploeotia vilrea, Lentomonas applanatum, and related flagellar apparatuses led to the conclusion that the basic euglenoid flagellar structure is symplesiomorphic but with enough variation to be taxonomically diagnostic.     

Hexamastix dobelli n.sp., a New Trichomonad Parasitic in the Starred Tortoise

Hexamastix dobelli n. sp. (Trichomonadidae) is described from the large intestine of the starred tortoise, Testu-do elegans Schoepff. This is the first species of Hexamastix to be reported from a chelonian. The organism is pyriform, oval, or round in shape. There are five anterior flagella, of which two are long and three short and a single recurrent flagellum, which equals the short anterior flagella in length. The axostyle is very slender and projects for some distance outside the body. The nucleus contains three to six granules and has no endosome. The pelta is crescent-shaped and the parabasal body is rod-like. Perinuclear granules are present in the anterior half of the body. The parasite is 6.0 to 16.5 μ long, 2.0 to 10.3 μ wide and the diameter of nucleus is 2.5 μ.     

Attachment of Vibrio alginolyticus to Glass Surfaces Is Dependent on Swimming Speed

The attachment of Vibrio alginolyticus to glass surfaces was investigated with special reference to the swimming speed due to the polar flagellum. This bacterium has two types of flagella, i.e., one polar flagellum and numerous lateral flagella. The mutant YM4, which possesses only the polar flagellum, showed much faster attachment than the mutant YM18, which does not possess flagella, indicating that the polar flagellum plays an important role. The attachment of YM4 was dependent on Na⁺ concentration and was specifically inhibited by amiloride, an inhibitor of polar flagellum rotation. These results are quite similar to those for swimming speed obtained under the same conditions. Observations with other mutants showed that chemotaxis is not critical and that the flagellum does not act as an appendage for attachment. From these results, it is concluded that the attachment of V. alginolyticus to glass surfaces is dependent on swimming speed.     

Ultrastructure and Organization of the Cytoskeleton in Oxymonas, an Intestinal Flagellate of Termites

ABSTRACT. Oxymonas has the characteristic structures and organization of other oxymonads including two separated pairs of basal bodies/flagella, a preaxostylar lamina, a paracrystalline axostyle, and an absence of mitochondria and Golgi. Like other Oxymonadinae genera it possesses a long proboscis, the rostellum which is terminated by the holdfast. Like the genera Pyrsonympha and Streblomastix, Oxymonas possesses a holdfast which permits it to attach to the cuticle of the termite hind-gut. This holdfast is subdivided into rhizoids and is filled with microfilaments. The rostellum is variable in length and contains two distinct microtubular bundles. One bundle is composed of convoluted microtubular ribbons which originate at the base of the holdfast and extend posteriorly along the rostellum and before penetrating into the cell body. The second bundle is composed of flexuous free microtubules which originate at different levels of the rostellum, increasing in number from top to base. They occupy the axial part of the rostellum and incorporate into the axostylar rows at the basal body/flagellar level. Microtubules of the paracrystalline axostyle are cross-linked by bridges forming parallel rows like in the contractile axostyles of other oxymonads such as Pyrsonympha and Saccinobaculus . Most of the microtubules of the axostyle originate at the flagellar/preaxostylar level but some originate from the axial flexous free microtubules of the rostellum, as indicated above. The possibility of an extension/retraction of the rostellum, suggested by other authors, is discussed.     

Independent analysis of the flagellum surface and matrix proteomes provides insight into flagellum signaling in mammalian-infectious Trypanosoma brucei

The flagellum of African trypanosomes is an essential and multifunctional organelle that functions in motility, cell morphogenesis, and host-parasite interaction. Previous studies of the trypanosome flagellum have been limited by the inability to purify flagella without first removing the flagellar membrane. This limitation is particularly relevant in the context of studying flagellum signaling, as signaling requires surface-exposed proteins in the flagellar membrane and soluble signaling proteins in the flagellar matrix. Here we employ a combination of genetic and mechanical approaches to purify intact flagella from the African trypanosome, Trypanosoma brucei, in its mammalian-infectious stage. We combined flagellum purification with affinity-purification of surface-exposed proteins to conduct independent proteomic analyses of the flagellum surface and matrix fractions. The proteins identified encompass a broad range of molecular functionalities, including many predicted to function in signaling. Immunofluorescence and RNA interference studies demonstrate flagellum localization and function for proteins identified and provide insight into mechanisms of flagellum attachment and motility. The flagellum surface proteome includes many T. brucei-specific proteins and is enriched for proteins up-regulated in the mammalian-infectious stage of the parasite life-cycle. The combined results indicate that the flagellum surface presents a diverse and dynamic host-parasite interface that is well-suited for host-parasite signaling.     

Digitized precision measurements of the movements of sea urchin sperm flagella.

High speed cinemicrographs were made of sea urchin sperm at temperatures varying from 22 to 6 degrees C. Apparatus, combining a television camera and a video digitizer, was constructed to scan individual flagellar images and to digitize the flagellar waveforms. With appropriate smoothing and averaging procedures, the rough data were condensed by a microcomputer into the coordinates of 20 points along a flagellum, spaced 2 microns apart. The curvature of the flagellum at these points was also computed. The coordinates of the flagellar positions were obtained to an accuracy of approximately +/- 0.1 micron, flagellar curvature to an accuracy of approximately +/- 50 cm-1. At all temperatures the amplitude of the flagella was found to vary with time in a purely sinusoidal fashion to within +/- 2%. The local curvature of the flagella had basically a purely sinusoidal time course to within +/- 50 cm-1, but a varying amount of asymmetry was present in the distal and the proximal ends of the flagella. This asymmetry in the curvature was related to the radius of the circular path of the sperm. The flagellar waveforms can probably be summarized in simple algebraic functions.     

Tritrichomonas mobilensis n. sp. (Zoomastigophorea: Trichomonadida) from the Bolivian Squirrel Monkey Saimiri boliviensis boliviensis1

ABSTRACT. A trichomonad flagellate, Tritrichomonas mobilensis n. sp., is described from the large intestine of the squirrel monkey, Saimiri boliviensis boliviensis. The organism has a lanceolate body 7–10.5 μm in length; a well developed undulating membrane; a stout, tubular axostyle with periaxostylar rings that terminate in a cone-shaped segment projecting from the posterior end of the cell; and a moderately wide costa. The anterior flagella are about as long as the body, and the recurrent flagellum is of the acroneme type. All its characteristics suggest that the new species belongs in the Tritrichomonas augusta type of the subfamily Tritrichomonadinae.     

ULTRASTRUCTURE OF THE BASAL APPARATUS AND PUTATIVE VESTIGIAL FEEDING APPARATUSES IN A QUADRIFLAGELLATE EUGLENOID (EUGLENOPHYTA)1

The flagellar apparatus and presumptive vestigial feeding apparatuses of a cold-water, photosynthetic, quadriflagellate euglenoid is described. The organism possesses two similar sets of flagella each consisting of one short and one long flagellum. Each pair of flagella is associated with three microtubular roots for a total of six roots in the basal apparatus. At the level of the ventral basal bodies, each intermediate root is nine-membered, while the ventral roots are composed of eight to nine microtubules. Only one of the ventral roots lines the single microtubule reinforced pocket. A four-membered dorsal root attaches to each dorsal basal body, and at the level of the reservoir each gives rise to a dorsal band. An additional bundle of microtubules, not arising from the microtubular roots of the basal apparatus, begins posterior to the basal apparatus as a small group of a few microtubules and extends anteriorly on the right ventral side of the reservoir ending at the canal. At the level of the stigma, the microtubules are organized into a multi-layered bundle that continues to increase in size and eventually splits to form two bundles at the level of the canal. We postulate that these bundles may represent the remnants of a rod-and-vane-type feeding apparatus like that found in many phagotrophic euglenoids.