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PubMed1978

Effects of methylglyoxal bis(ganylhydrazone) on trypanosomatid flagellates: inhibition of growth and nucleoside incorporation in Trypanosoma brucei.

Methyglyoxal bis (guanylhydrazone) (MGBG) at 0.5 mM had little effect in vitro on Blastocrithidia culicis, Crithidia oncopelti, and Leishmania spp., but completely inhibited growth of Trypanosoma brucei. Inhibition became irreversible after a 3-h exposure of T. brucei culture procyclics. Treated organisms remained motile, but failed to divide. Polyamines, spermidine, and spermine, did not reverse the anti-trypanosome action of MGBG (preloading of cells or concurrent administration). Two intraperitoneal injections of the drug at a concentration of 50 mg/kg body weight at a 1-day interval greatly reduced the parasitemia of T. brucei and T. congolense in rats. Trypanosome infections, however, relapsed and killed the animals in 6 days after treatment. It was evident from the results of tracer experiments with T brucei that MGBF significantly lowered incorporation of [3H]thymidine by culture pocyclics and of [3H]uridine by bloodstream forms; in both stages [3H]leucine incorporation was only slightly inhibited. It is suggested that MGBG interferes with nucleoside incorporation by Trypanosoma and that its mode of action is different in bloodstream and culture procyclics.

Animals↗
PubMed1988

Linkage disequilibrium in natural populations of Trypanosoma cruzi (flagellate), the agent of Chagas' disease.

We have studied linkage disequilibrium in natural populations of Trypanosoma cruzi, the agent of Chagas' disease, by analyzing (i) a set of 524 stocks from the whole geographical range of the parasite, characterized at four gene loci coding for enzymes; (ii) a subsample of 121 stocks characterized at 12 enzyme loci; and (iii) a subset of 386 stocks from six locations in Bolivia, characterized by four enzyme loci. Our results show that the linkage disequilibrium reaches the maximum possible value, given the observed allelic frequencies, for almost all the locus pairs. This result is most consistent with the hypothesis that genetic recombination is absent or very rare in T. cruzi natural populations. Partition of the linkage disequilibrium variance for the six Bolivian populations shows that both inter- and intrapopulation components are substantial and that the relationships among the components are D2IS less than D2ST, and D'2IS less than D'2ST. These inequalities are interpreted as the result of an interplay between genetic drift, rare or absent mating, and clonal selection in generating linkage disequilibrium in T. cruzi populations.

Alleles↗
PubMedDate not supplied

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.

Animals↗
PubMedDate not supplied

Primary structure and phylogenetic relationships of glyceraldehyde-3-phosphate dehydrogenase genes of free-living and parasitic diplomonad flagellates.

Complete nucleotide sequences have been established for two genes (gap1 and gap2) coding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) homologs in the diplomonad Giardia lamblia. In addition, almost complete sequences of the GAPDH open reading frames were obtained from PCR products for two free-living diplomonad species, Trepomonas agillis and Hexamita inflata, and a parasite of Atlantic salmon, an as yet unnamed species with morphological affinities to Spironucleus. Giardia lamblia gap1 and the genes from the three other diplomonad species show high similarity to each other and to other glycolytic GAPDH genes. All amino-acyl residues known to be highly conserved in this enzyme are also conserved in these sequences. Giardia lamblia gap2 gene is more divergent and its putative translation reveals the presence of a cysteine and serine-rich insertion resembling a metal binding finger. This motif has not yet been noted in other GAPDH molecules. All sequences contain an S-loop signature with characteristics close to those of eukaryotes. In phylogenetic reconstructions based on the derived amino acid sequences with neighbor-joining, parsimony and maximum-likelihood methods the four typical GAPDH sequences of diplomonads cluster into a single clade. Within this clade, G. lambia gap1 shares a common ancestor with the rest of the genes. The latter are more closely related to each other, indicating an early separation of the lineage leading to the genus Giardia from the lineage encompassing the morphologically less differentiated genera, Trepomonas, Hexamita and that of the unnamed species. This result is discordant with the orthogonal evolution of diplomonads suggested on the basis of comparative morphology. In neighbor-joining reconstructions G. lamblia gap2 occupies a variable position, due to its great divergence. In parsimony and maximum likelihood analysis however, it shares a most recent common ancestor with the typical G. lamblia gap1 gene, suggesting that it diverged after the separation of the Giardia lineage. The position of the diplomonad clade in broader phylogenetic reconstructions is firmly within the typical cytosolic glycolytic representatives of GAPDH of eukaryotes.

Animals↗
PubMedDate not supplied

Ribosomal RNA phylogeny of bodonid and diplonemid flagellates and the evolution of euglenozoa.

Euglenozoa is a major phylum of excavate protozoa (comprising euglenoids, kinetoplastids, and diplonemids) with highly unusual nuclear, mitochondrial, and chloroplast genomes. To improve understanding of euglenozoan evolution, we sequenced nuclear small-subunit rRNA genes from 34 bodonids (Bodo, Neobodo, Parabodo, Dimastigella-like, Rhynchobodo, Rhynchomonas, and unidentified strains), nine diplonemids (Diplonema, Rhynchopus), and a euglenoid (Entosiphon). Phylogenetic analysis reveals that diplonemids and bodonids are more diverse than previously recognised, but does not clearly establish the branching order of kinetoplastids, euglenoids, and diplonemids. Rhynchopus is holophyletic; parasitic species arose from within free-living species. Kinetoplastea (bodonids and trypanosomatids) are robustly holophyletic and comprise a major clade including all trypanosomatids and most bodonids ('core bodonids') and a very divergent minor one including Ichthyobodo. The root of the major kinetoplastid clade is probably between trypanosomatids and core bodonids. Core bodonids have three distinct subclades. Clade 1 has two distinct Rhynchobodo-like lineages; a lineage comprising Dimastigella and Rhynchomonas; and another including Cruzella and Neobodo. Clade 2 comprises Cryptobia/ Trypanoplasma, Procryptobia, and Parabodo. Clade 3 is an extensive Bodo saltans species complex. Neobodo designis is a vast genetically divergent species complex with mutually exclusive marine and freshwater subclades. Our analysis supports three phagotrophic euglenoid orders: Petalomonadida (holophyletic), Ploeotiida (probably holophyletic), Peranemida (paraphyletic).

Animals↗
PubMedDate not supplied

Comparative cytological study of four species in the genera Holomastigotes and Uteronympha n. comb. (Holomastigotidae, Parabasalia), symbiotic flagellates of termites.

Cytological features observed using light, immunofluorescence, and electron microscopy of the type species Holomastigotes elongatum were compared with Holomastigotes lanceolata and to Holomastigotes flexuosum n. sp. The comparison was extended to Spirotrichonymphella pudibunda and to Uteronympha africana n. gen. n. sp., in order to present the common features of the Holomastigotidae (Spirotrichonymphida). All these species have anterior basal bodies bearing microfibrillar or striated rootlets that are reduced or absent posterior to the nucleus. An axostylar trunk is present in Holomastigotes elongatum and Holomastigotes lanceolata, whereas the axostylar microtubules do not extend posterior to the nucleus in Holomastigotes flexuosum, Spirotrichonymphella, and Uteronympha. Uteronympha africana has specific features, such as a transverse plaque inside the columella from which arise microtubules capping the nucleus, and as in Spirotrichonympha the striated lamina is present all along the flagellar lines. Uteronympha africana has ability to endocytose wood particles in addition to the osmotrophic feeding that occurs in all the Holomastigotidae.

Animals↗
PubMed2001

Difference between forward and backward swimming speeds of the single polar-flagellated bacterium, Vibrio alginolyticus.

The forward and backward swimming speeds and periods of a Vibrio alginolyticus strain that has a single polar flagellum were measured. The backward swimming speeds were 1.5 times greater than the forward ones on average and the average period of backward swimming was shorter than forward swimming. However, the swimming speed and period were not correlated. Similar results were obtained for a mutant that has a 1.6 times longer flagellum on average.

Flagella↗
PubMed1984

Effects of diazepam on mitosis and basal body duplication of synchronously dividing flagellate cells.

We report here that diazepam (Valium, Roche) has an inhibitory effect on proliferation of synchronously dividing cultures of Dunaliella, whenever the drug is added during the cell cycle. The drug induced an accumulation of abnormal mitotic figures after 17 to 24 hr of treatment with the chromosomes distributed around the nuclei and a monopolar spindle, although the pole-to-chromosome microtubules were well-formed. Diazepam seemed to affect mitosis by inhibiting the separation of the basal bodies, whose duplication was perturbed in a dose-related manner. After 48 hr of treatment, the nucleus returned to interphase without having undergone mitosis, but cytokinesis might have taken place. The mechanism of this action of diazepam on mitosis remains to be elucidated. However, it does not appear to act in the same way here as it does on the central nervous system.

Cell Cycle↗