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ABSTRACT. Meglitschia mylei n. sp. found in the gall bladder of the teleostean fish Myleus rubripinnis (Serrasalmidae) from the middle Amazonian region of Brazil is described using light and transmission electron microscopy. The spores observed in the bile averaged 24.6±0.8 μm long, 8.7±0.4 μm wide and 5.1±0.3 μm thick and were strongly furcate and arcuate ∩-shaped composed of two symmetric equal-sized valves, up to ∼70 nm thick. Each valve possessed one opposed tapering appendage, 20.1±0.7 μm long, oriented parallel towards the basal tip of the appendages and joined along a right suture line forming a thick strand. The strand goes around the central part of the spore, which in turn surrounds two equal and symmetric spherical polar capsules (PC), 2.1±0.3 μm in diameter, located at the same level. Each capsule contains a polar filament with five (rarely six) coils. The binucleate sporoplasm was irregular in shape, contained several sporoplasmosomes, ∼175 nm in diameter and filled all the space of the two caudal appendages. Based on the arc shape of the spore with two tapering caudal appendages oriented to the basis of spores, on the number and position of the PC and of the polar filament coils and arrangements, and on the host specificity, we propose the name M. mylei n. sp. for this new myxozoan. Accordingly, this is the second described species of this genus. [ABSTRACT FROM AUTHOR]

We have generated 18S rRNA sequences for peritrichs collected in Brazil, including four Opercularia species, two different populations of Epistylis plicatilis (one epibiont and another free-living), and one additional Epistylis species. Our Opercularia species clustered with the previously available Opercularia microdiscum, corroborating the monophyly of this genus. The Epistylis sampled here clustered with previously sequenced species of this genus. The two populations of E. plicatilis collected in Brazil clustered closely together despite their different ecological contexts, whereas both were very divergent from the sample assigned to the same species previously sampled in China. If affirmed by additional morphological corroboration of species assignment, this observation would indicate that samples from different continents morphologically allocated in the same species may in fact belong to distant evolutionary lineages. More broadly, our results support the recognition of two major clades within Peritrichia. Given the robustness of their support, we suggest that these two clades should be formally recognized as orders, and propose the names Vorticellida and Operculariida to designate them. Furthermore, Epistylis species occurred in both orders, tending to occupy basal positions. This suggests that characters used to define this genus may be plesiomorphic for Peritrichia, so that Epistylis may in fact represent an assemblage of basal species retaining ancestral features. [ABSTRACT FROM AUTHOR]

Plant trypanosomatids cause lethal vascular wilting in palms of the Arecaceae family. Infections, affecting plants in South and Central America, can result in significant economic loss. The study of trypanosomatids that cause these diseases has been complicated due to the inability to culture these organisms for in vitro analyses. To develop a protocol that would facilitate studies of trypanosomatids, continuous in vitro cultures of phloemic trypanosomatids were established from apical stems of diseased coconut trees collected in endemic and non-endemic regions of Brazil (the states of Bahia and Rio de Janeiro, respectively). Although attempts at establishing axenic cultures were unsuccessful, it was found that trypanosomatid co-cultures could be successfully established and maintained. The procedure was to preculture media with 104 Aedes albopictus cells in Grace's medium supplemented with 10% heat-inactivated fetal bovine serum (without antibiotics or fungicides) for 3 d before adding 106 trypanosomatids/ml harvested from either fresh apical stem extracts or with 2 mm3 fragments of coconut apical stems. By day 7 under these conditions the parasites grew exponentially. Using this strategy, two isolates were identified and have been maintained in our laboratory for over 400 passages, demonstrating the efficacy of this culturing procedure. In situ the organisms were observed in vascular bundles and inside sieve elements of the phloem of diseased palms. In vitro parasites retained their mobility. Morphometric analysis revealed differences between Bahia and Rio de Janeiro isolates. [ABSTRACT FROM AUTHOR]

A myxosporean parasitizing the gill filaments of the freshwater teleost fish Centromochlus heckelii collected in the Tocantins River (Lower Amazonian Region, Brazil) is described using light and electron microscopy. This parasite produces spherical to ellipsoidal cyst-like plasmodia up to 250 μm in diameter, with a thick wall strengthened by several stratified juxtaposed crossed collagen layers, whose thickness varies according to the number of the layers. Several compressed fibroblasts are observed among the collagen fibrils. Deposits of spherical dense material are scattered at the internal periphery of the cysts. Plasmodia and different developmental stages, including immature and mature spores, filled the central region of the cysts. The spore body is ellipsoidal in valvar view and biconvex in sutural view. It is formed by two equal-sized and symmetric valves measuring 12.7 μm long (12.2–13.1) ( n=50), 6.6 μm wide (6.3–6.9) ( n=25), and 4.0 μm (3.7–4.4) ( n=20) thick. A thin layer formed by fine and anastomosed microfibrils is observed at the spore surface. Two equal, elongated pyriform polar capsules measure 2.9 μm (2.7–3.3) × 1.7 μm (1.4–2.0) ( n=25), each containing four or five oblique polar filament coils. The binucleated sporoplasm contains numerous spherical sporoplasmosomes, glycogen particles, and a large vacuole with fine granular matrix. Based on the morphological and ultrastructural differences and specificity of the host, we describe this isolate as a new myxosporidian, Myxobolus heckelii n. sp. (Myxozoa, Myxosporea). [ABSTRACT FROM AUTHOR]