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1.
A new histozoic species of myxosporean (Henneguya schizodon n. sp.) is described from the Amazon River teleost fish Schizodon fasciatus Spix & Agassiz, 1892 (Characiformes, Anostomidae). The plasmodia, which showed asynchronous development, were located in the kidney of the host. The spore body was ellipsoidal and was 13.1 (12-14) micron long by 3.3 (3-4) micron wide. The total length of the spore was 28.9 (27-30) micron, and each value had a caudal process measuring 16.3 (15-17) micron. The polar capsules were 5.4 (5-6) micron long by 1.3 (1-1.5) micron wide, and each had a polar filament with 8-10 coils. The characteristics of the species were compared with nearly all the species described so far, including all the species reported from South American fishes. This comparison allows to consider the materials as a new species, and the name Henneguya schizodon n. sp. is proposed. 相似文献
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This study reports light and electron microscopical aspects of a myxosporean found in the gills of the freshwater teleost Astyanax keithi Géry, Planquete & Le Bail, 1996 (family Characidae), collected from the estuarine region of the Amazon River, near Belém, Brazil. The prevalence of infection was 23%. In interlamellar spaces of the gills, ellipsoidal whitish cyst-like plasmodia structures were present, which contained spores. The spores had a spermatozoa-like appearance (47.8 +/- 0.71 microm in total length) with a fusiform body (15.2 +/- 0.77 pm in length, 5.7 +/- 0.71 microm in width and 4.2 +/- 0.31 microm in thickness), and each of the 2 valves presented a tapering tail (32.6 +/- 1.11 microm in length). The valves surrounded a binucleate sporoplasm cell and 2 polar capsules (5.0 +/- 0.13 microm in length, 1.5 +/- 0.07 microm in width) that contained 8 to 9 coils of the polar filament. In the sporoplasm, several unique sporoplasmosomes were visible. A synoptic table of spore measurements of known Brazilian Henneguya species is presented. The spores differed from those of previously described species. Based on spore morphology, it is concluded that this species belongs to the family Myxobolidae, genus Henneguya, and that it constitutes a new species: H. astyanax n. sp. 相似文献
3.
Henneguya rondoni n. sp. found in the peripheral lateral nerves located below the two lateral lines of the fish Gymnorhamphichthys rondoni (Teleostei, Rhamphichthyidae) from the Amazon river is described using light and electron microscopy. Spherical to ellipsoid cysts measuring up to 110 microm in length contained only immature and mature spores located in close contact with the myelin sheaths of the nervous fibres. Ellipsoidal spores measured 17.7 (16.9-18.1)-microm long, 3.6 (3.0-3.9)-microm wide, and 2.5 (2.2-2.8)-microm (n=25) thick. The spore body measuring 7.0 (6.8-7.3)-microm long was formed by two equal symmetric valves, each with an equal tapering tail 10.7 (10.3-11.0) microm in length. The tails were composed of an internal dense material surrounded by an external homogeneous sheath of hyaline substance. The valves surrounded two equal pyriform polar capsules measuring 2.5 (2.2-2.8)-microm long and 0.85 (0.79-0.88)-microm (n=25) wide and a binucleated sporoplasm cell containing globular sporoplasmosomes 0.38 (0.33-0.42) microm (n=25) in diam. with an internal eccentric dense structure with half-crescent section. Each polar capsule contains an anisofilar polar filament with 6-7 turns obliquely to the long axis. The matrix of the polar capsule was dense and the wall filled with a hyaline substance. The spores differed from those of previously described species. Based on the ultrastructural morphology of the spore and specificity to the host species, we propose a new species name H. rondoni n. sp. 相似文献
4.
Henneguya rhamdia n. sp. is described in the gill filaments of the teleost fish Rhamdia quelen, collected from the Peixe Boi River, State of Pará, Brazil. This myxosporean produced spherical to ellipsoidal plasmodia, up to 300 microm in diameter, which contained developmental stages, including spores. Several dense bodies up to 2 microm in diameter were observed among the spores. The spore body was ellipsoidal (13.1 microm in length, 5.2 microm in width, and 2.5 microm in thickness) and each of the two valves presented a tapering tail (36.9 microm in length). These valves surrounded the binucleated sporoplasm cell and two equal ellipsoidal polar capsules (4.7 x 1.1 microm), which contained 10-11 (rarely 12) polar filament coils. The sporoplasm contained sporoplasmosomes with a laterally eccentric dense structure with a half-crescent section. Based on the data obtained by electron microscopy and on the host specificity, the spores differed from previously described Henneguya species, mainly in their shape and size, number and arrangement of the polar filament coils, and sporoplasmosome morphology. 相似文献
5.
Light and electron microscopical data on a myxosporidian found in the testis of Moenkhausia oligolepis Gunther (Teleostei, Characidae, Tetragonopterinae) from the lower Amazon River near Belém, Brazil, are described. Based on spore morphology, we conclude that this species belongs to the family Myxobolidae and genus Henneguya. Mature spores (total length 27.5 (27.0–28.5) µm) were observed at the periphery of the testis. The ellipsoidal spore body consists of two unequal shell valves adhering together along the suture lines. The spore body is ellipsoidal, 14.0 µm long and 6.5 µm wide. Each valve tapers to a single caudal projection, forming a 13.5 µm long tail (13.0–14.5 µm). The spore is surrounded by a homogenous dense sheath. The polar capsules, measuring 9.0 × 2.0 µm, contain 12–13 coils of the polar filaments. Morphological differences between this material and other species of the genus Henneguya indicated the erection of a new species, which was named H. testicularis. The taxonomic affinities of this parasite are discussed. 相似文献
6.
A new myxosporean species is described from the fish Semaprochilodus insignis captured from the Amazon River, near Manaus. Myxobolus insignis sp. n. was located in the gills of the host forming plasmodia inside the secondary gill lamellae. The spores had a thick wall (1.5-2 microm) all around their body, and the valves were symmetrical and smooth. The spores were a little longer than wide, with rounded extremities, in frontal view, and oval in lateral view. They were 14.5 (14-15) microm long by 11.3 (11-12) microm wide and 7.8 (7-8) microm thick. Some spores showed the presence of a triangular thickening of the internal face of the wall near the posterior end of the polar capsules. This thickening could occur in one of the sides of the spore or in both sides. The polar capsules were large and equal in size surpassing the midlength of the spore. They were oval with the posterior extremity rounded, and converging anteriorly with tapered ends. They were 7.6 (7-8) microm long by 4.2 (3-5) microm wide, and the polar filament formed 6 coils slightly obliquely to the axis of the polar capsule. An intercapsular appendix was present. There was no mucous envelope or distinct iodinophilous vacuole. 相似文献
7.
Light and electron microscopy studies of a myxosporean, parasitic in the intertubular interstitial tissue of the kidney of the freshwater teleost fish Metynnis maculatus Kner, 1860 (Characidae) from the lower Amazon River (Brazil), are described. We observed polysporic histozoic plasmodia delimited by a double membrane and with several pinocytic channels and containing several life cycle stages, including mature spores. The spore body was of pyriform shape and was 21.0 microm long, 8.9 microm wide and 7.5 microm thick. Elongated-pyriform polar capsules were of equal size (12.7 x 3.2 microm) and contained a polar filament with 14 or 15 coils. The spore features fit those of the genus Myxobolus. Densification of the capsular primordium matrix, which increased in density from the inner core outwards, differentiating at the periphery into small microfilaments measuring 45 nm each, and tubuli arranged in aggregates and dispersed within the capsular matrix of the mature spores, are described. Based on the morphological differences and specificity of the host, we propose the creation of a new species named Myxobolus maculatus n. sp. 相似文献
8.
ABSTRACT. A new species of myxosporean from the gill filaments of the freshwater teleost fish, Acestrorhynchus falcatus collected in the Amazon river is described from light and transmission electron microscope observations. The mature spores (total length 32.3 [30.7–35.1] μ) and all developmental stages were found in the same sporogonic plasmodium. The ellipsoidal spore body consists of 2 unequal shell valves adhering together along the suture lines. Each valve, tapering as a caudal projection, forms a long tail (length 20.5 [18.0–21.7] μm). The tail was surrounded by a homogeneous sheath on its length. The polar capsules measuring 3.1 × 1.2 μm contain 3–4 coils of the polar filament. All surfaces of the immature and mature spores were surrounded by a closely adherent homogenous structural sheath, mainly thicker around the tails. The taxonomic affinities of this parasite to other species are discussed. 相似文献
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11.
Alexandre Salino Rozijane Santos Fernandes Marcio Roberto Pietrobom 《Nordic Journal of Botany》2011,29(5):611-614
A new species of Thelypteris subgenus Goniopteris (Thelypteridaceae) is described and illustrated: Thelypteris amazonica Salino & R. S. Fernandes is apparently most similar to Thelypteris anoptera (Kunze) C. Chr. (Brazil‐Bahia) and T. abrupta (Desv.) Proctor (Antilles, Central America, South America), but differs from both by the clavate vein ends, basal vein pairs from adjacent segments not united below the sinuses, and petioles with simple and stellate hairs. Thelypteris amazonica is known only from Amazonian Brazil. 相似文献
12.
C. R. Franchina 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,181(2):111-119
I recorded the electric organ discharges (EODs) of 331 immature Brachyhypopomus pinnicaudatus 6–88 mm long. Larvae produced head-positive pulses 1.3 ms long at 7 mm (6 days) and added a second, small head-negative phase at 12 mm. Both phases shortened duration and increased amplitude during growth. Relative to the whole EOD, the negative phase increased duration until 22 mm and amplitude until 37 mm. Fish above 37 mm produced a “symmetric” EOD like that of adult females. I stained cleared fish with Sudan black, or fluorescently labeled serial sections with anti-desmin (electric organ) or anti-myosin (muscle). From day 6 onward, a single electric organ was found at the ventral margin of the hypaxial muscle. Electrocytes were initially cylindrical, overlapping, and stalk-less, but later shortened along the rostrocaudal axis, separated into rows, and formed caudal stalks. This differentiation started in the posterior electric organ in 12-mm fish and was complete in the anterior region of fish with “symmetric” EODs. The lack of a distinct “larval” electric organ in this pulse-type species weakens the hypothesis that all gymnotiforms develop both a temporary (larval) and a permanent (adult) electric organ. Accepted: 1 March 1997 相似文献
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14.
We describe the microsporidian Amazonspora hassar n. gen., n. sp. from the gill xenomas of the teleost Hassar orestis (Doradidae) collected in the estuarine region of the Amazon River. The parasite appeared as a small whitish xenoma located in the gill filaments near the blood vessels. Each xenoma consisted of a single hypertrophic host cell (HHC) in the cytoplasm of which the microsporidian developed and proliferated. The xenoma wall was composed of up to approximately 22 juxtaposed crossed layers of collagen fibers. The plasmalemma of the HHC presented numerous anastomosed, microvilli-like structures projecting outward through the 1-3 first internal layers of the collagen fibrils. The parasite was in direct contact with host cell cytoplasm in all stages of the cycle (merogony and sporogony). Sporogony appears to divide by plasmotomy, giving rise to 4 uninucleate sporoblasts, which develop into uninucleate spores. The ellipsoidal spores measured 2.69 +/- 0.45 x 1.78 +/- 0.18 microm, and the wall measured approximately 75 nm. The anchoring disk of the polar filament was subterminal, being shifted laterally from the anterior pole. The polar filament was arranged into 7-8 coils in a single layer in the posterior half of the spore, surrounding the posterior vacuole. The polaroplast surrounded the uncoiled portion of the polar filament, and it was exclusively lamellar. The spores and different life-cycle stages were intermingled within the cytoplasm of the HHC, surrounding the central hypertrophic deeply branched nucleus. The ultrastructural morphology of this microsporidian parasite suggests the erection of a new genus and species. 相似文献
15.
William G. R. Crampton Lauren J. Chapman Jason Bell 《Environmental Biology of Fishes》2008,83(2):223-235
Gymnotiform electric fish assemblage structure is strongly correlated to dissolved oxygen (DO) availability, which exhibits
considerable heterogeneity among Amazonian aquatic systems. DO is known to influence the respiratory morphology of gymnotiform
fishes, and yet species-level variation among congeners endemic to alternative DO regimes has not been examined. We describe
the DO environment experienced by four congeneric species of gymnotiforms (Brachyhypopomus) and correlate this to quantitative variation in a suite of gill metrics. Whitewater floodplain lakes flanking nutrient-rich
whitewater rivers are seasonally hypoxic, exhibiting oxygen concentrations close to 0 mg/l from late April until September.
In contrast, DO levels in blackwater floodplain lakes and in terra firme forest stream habitats remain high throughout the
year. Two common species of Brachyhypopomus restricted to periodically anoxic whitewater floodplain exhibited a substantially greater gill size than two common species
restricted to the perpetually well-oxygenated waters of blackwater floodplain lakes and terra firme stream systems. Discriminant
Function Analysis (DFA) based on gill metrics separated the species that live in seasonally anoxic whitewater floodplain species
from those that live in perpetually-well oxygenated habitats. Our observations suggest a history of adaptive divergence in
the gill morphology of Brachyhypopomus associated with oxygen availability. 相似文献
16.
Azevedo C Casal G Marques D Silva E Matos E 《The Journal of eukaryotic microbiology》2011,58(2):88-93
Light and electron microscopy studies of a myxosporean, parasitizing the gill filaments of the freshwater fish Brycon hilarii (Valenciennes, 1850) (Characidae) collected in the Paraguay River (18°49'S, 57°39'W) (Pantanal), Brazil, is described. This parasite produces spherical to ellipsoidal polysporic histozoic plasmodia (Pmd) (up to ~180 μm in diameter) delimited by a double membrane and with several pinocytic channels. The plasmodial cyst contained the youngest developmental stages at the cortical periphery and immature and mature spores more internally. The Pmd developed near the cartilaginous structure of the gill filament, forming a prominent deformation where the gill lamellae disappear. Pyriform spores measured 6.9±0.6 (range 6.5-7.2) μm long, 4.2±0.5 (range 3.9-4.8) μm wide, and 2.5±0.7 (range 1.9-2.8) μm thick. The spores composed of two equal shell valves (~70 nm thick), adhering together along the straight suture line, surrounded two equal symmetric and elongated to pyriform polar capsules (PC) 4.2±0.6 (range 3.8-4.7) × 1.9±0.6 (1.7-2.5) μm; each PC contained a coiled polar filament with eight or nine (rarely 10) turns and a binucleated sporoplasm cell. Dense irregular masses were observed among the polar filaments coils. An intercapsular appendix was not observed. The sporoplasm contained several globular sporoplasmosomes randomly distributed among an extensive rough endoplasmic reticulum system with numerous vesicles and cisternae. Based on the morphological and ultrastructural differences and specificity of the host, we establish the new species, Myxobolus brycon n. sp. 相似文献
17.
Aurelio Ciancio Mariantonietta Colagiero Laura Cristina Rosso Santos Nelida Murga Gutierrez Gaetano Grasso 《Mycoscience》2013,54(5):378-386
A new species of Hirsutella was isolated from unidentified mites on Petri plates inoculated with soil and root fragments collected from asparagus rhizosphere at Virú, Northern Peru. The fungus differs from other Hirsutella species by an envelope surrounding the conidium, conidia dimension and DNA sequences. In PDA cultures, the mycelium produced aerial hyphae with conidiogenous cells mainly at right angles, occasionally showing a secondary conidiophore. The solitary conidia are cymbiform, slightly apiculate, 5.0–6.0 × 3.0–4.0 μm. Phylogenetic analyses with partial rRNA and β-tubulin gene sequences confirmed the fungus as an Hirsutella (Ophiocordycipitaceae). Closest species shown by maximum likelihood and neighbor-joining trees were H. nodulosa and H. aphidis, from which the new species differs for conidium or conidiogenous cells dimensions, lack of synnemata and host type. A recombination event was also detected in the rRNA of the holotype strain, involving Ophiocordyceps sinensis as major parent and O. cochlidiicola as minor parent. A complement, inverted insertion was also found in its rRNA, involving part of the ITS2 and 5.8S regions, flanked by two short nucleotide arrays. Due to conidia dimension and phylogenetic position, the fungus is described as Hirsutella tunicata sp. nov. A review of mononematous Hirsutella species is provided. 相似文献
18.
Development of a new species of malacosporean myxozoan (Buddenbrockia allmani n. sp.) in the bryozoan Lophopus crystallinus is described. Early stages, represented by isolated cells or small groups, were observed in the host's body wall or body cavity. Multiplication and rearrangement of cells gave an outer cell layer around a central mass. The outer cells made contact by filopodia and established adherens junctions. Sporoplasmosomes were a notable feature of early stages, but these were lost in subsequent development. Typical malacosporean sacs were formed from these groups by attachment of the inner (luminal) cells by a basal lamina to the outer layer (mural cells). Division of luminal cells gave rise to a population of cells that was liberated into the lumen of the sac. Mitotic spindles in open mitosis and prophase stages of meiosis were observed in luminal cells. Centrioles were absent. Detached luminal cells assembled to form spores with four polar capsules and several valve cells surrounding two sporoplasms with secondary cells. Restoration of sporoplasmosomes occurred in primary sporoplasms. A second type of sac was observed with highly irregular mural cells and stellate luminal cells. A radially striated layer and dense granules in the polar capsule wall, and previous data on 18 rDNA sequences enabled assignment of the species to the genus Buddenbrockia, while specific diagnosis relied on the rDNA data and on sac shape and size. 相似文献
19.
Renata Giassi Udulutsch Marco Antonio de Assis Pedro Dias 《Nordic Journal of Botany》2009,27(6):449-453
A new species of Adenocalymma (Bignoniaceae, Bignonieae) is described and illustrated. Adenocalymmacalcareum Udulutsch & P. Dias sp. nov. is known only from the Rondônia State of western Brazil. Its main diagnostic features are dark yellow corolla provided with nectaries, lepidote ovary, glabrous capsule with prominently thick and calcareous wings and wingless seeds. A discussion on the relationships of the new taxon and a key to all species of Adenocalymma reported from Brazilian Amazonia are provided. 相似文献
20.
The study of 102 teleost freshwater fishes of Sanaga basin in Cameroon revealed the presence of three myxosporean species, among which two were new. Host fishes were of three families: Centropomidae, Cichlidae and Characidae. New species were identified as Henneguya mbakaouensis sp. nov., a gill parasite of Lates niloticus and Myxobolus nounensis sp. nov. found in the kidney and spleen of Sarotherodon galilaeus and Tilapia mariae. Myxobolus hydrocyni Kosto?ngue & Toguebaye, 1994, previously described in Chad, was also found in Cameroon; complementary informations were given on that parasite which seemed to be specific to its host. 相似文献