Morphology and host-parasite interaction of Henneguya azevedoi n. sp., parasite of gills of Leporinus obtusidens from Mogi-Guaçu River, Brazil. Parasitol Res

Departamento de Biologia Animal da Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brazil.
Parasitology Research (Impact Factor: 2.1). 08/2011; 110(2):887-94. DOI: 10.1007/s00436-011-2571-5
Source: PubMed


Henneguya azevedoi n. sp. is described from the piava (Leporinus obtusidens). Between 2005 and 2007, 60 fish were collected from the Mogi-Guaçu River near Cachoeira de Emas Falls located in the municipality of Pirassununga, state of São Paulo, Brazil. A total of 70% had plasmodia of the parasite. The plasmodia were white, spherical, and measured 40-200 μm in diameter. Histopathological analysis revealed that the development of the parasite was intralamellar and caused stretching of the epithelium, with accentuated deformation, as well as compression of the capillary and adjacent tissues. Ultrastructural analysis revealed that the wall of the plasmodium was a single membrane in direct contact with the host cells and contained pinocytic canals that extended into the plasmodium. The development of the parasite was asynchronous, with the earliest stages at the periphery and mature spores in the central region. Mature spores were elongated in the frontal view [mean ± standard deviation (range)]: 45.2 ± 0.6 (45.0-47.0) μm in total length, 10.0 ± 0.07 (9.9-10.2) μm in body length, 35.6 ± 0.9 (34.9-36.5) μm in caudal process length, and 4.4 ± 0.4 (4.0-5.0) μm in body width. The polar capsules were elongated and equal in size: 3.8 ± 0.3 (3.5-4.0) μm in length and 1.0 μm in width. The polar filaments were coiled in six to seven turns and perpendicular to the axis of the capsule. Scanning electron microscopy revealed smooth valves and a conspicuous rim around the spore body. This is the first time that a myxosporean has been reported in L. obtusidens.

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    • "In South America, the plasmodia of Henneguya azevedoi are located primarily, but not limited to the apical end of the lamellae of piava Leporinus obtusidens (Barassa et al. 2012). In a survey of Asian redtail catfish Hemibagrus nemurus from Malaysia, Henneguya mystusia was observed forming large plasmodia at the tip of gill filaments, deforming the lamellar structure. "
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    ABSTRACT: There are more than 200 species of Henneguya described from fish. Of these, only three life cycles have been determined, identifying the actinospore and myxospore stages from their respective hosts. Two of these life cycles involve the channel catfish (Ictalurus punctatus) and the freshwater oligochaete Dero digitata. Herein, we molecularly confirm the life cycle of a previously undescribed Henneguya sp. by matching 18S ribosomal RNA (rRNA) gene sequence of the myxospore stage from channel catfish with the previously described actinospore stage (Aurantiactinomyxon mississippiensis) from D. digitata. Gill tissue from naturally infected channel catfish contained pseudocysts restricted to the apical end of the primary lamellae. Myxospores were morphologically consistent with Henneguya spp. from ictalurid fishes in North America. The spores measured 48.8 ± 4.8 μm (range = 40.7-61.6 μm) in total spore length. The lanceolate spore body was 17.1 ± 1.0 μm (14.4-19.3 μm) in length and 5.0 ± 0.3 μm (4.5-5.5 μm) in width. The two polar capsules were 6.2 ± 0.4 μm (5.8-7.0 μm) long and 5.0 ± 0.3 μm (4.5-5.5 μm) wide. The polar capsule contained eight to nine coils in the polar filament. The two caudal processes were of equal length, measuring 31.0 ± 4.1 μm (22.9-40.6 μm). The 1980-bp 18S rRNA gene sequence obtained from two excised cysts shared 99.4 % similarity (100 % coverage) to the published sequence of A. mississippiensis, an actinospore previously described from D. digitata. The sequence similarity between the myxospore from channel catfish and actinospore from D. digitata suggests that they are conspecific, representing alternate life stages of Henneguya mississippiensis n. sp.
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    ABSTRACT: Myxosporean genera Henneguya and Myxobolus (Bivalvulida: Myxobolidae) are closely related in morphology and molecular phylogeny, speciose with approximately 1,000 nominal species. The majority of them are recorded from freshwater fish worldwide, and few are known from marine fish. In this study, three myxobolid spp. are described from marine fish around Japan. Two novel Henneguya spp., Henneguya ogawai sp. n. and Henneguya yokoyamai sp. n., are described from two black sea breams (Acanthopagrus schlegelii) fished in the Inland Sea (Setonaikai), Japan. Plasmodia of the former species were localized in the esophageal or intestinal wall, and those of the latter species were in the wall of the gall bladder and peritoneum. Spore development in plasmodia of these two species was synchronous. The spore body of H. ogawai sp. n. was 11.0 (8.9-12.2) μm in length, 6.9 (6.3-7.5) μm in width, 5.9 (5.2-6.6) μm in thickness, with a bifurcated caudal process of equal length, 10.0 (8.4-12.7) μm long; total spore length, 21.1 (19.2-23.4) μm. It contained two polar capsule, 4.3 (3.8-5.2) × 1.9 (1.4-2.3) μm. The spore body of H. yokoyamai sp. n. was 11.0 (10.1-13.7) μm in length, 7.1 (6.6-7.5) μm in width, and 5.6 (4.5-6.4) μm in thickness, with a bifurcated caudal process of equal length, 14.1 (10.8-17.0) μm long; total spore length, 25.0 (21.9-29.2) μm. It contained two polar capsules, 3.7 (3.1-4.2) × 2.0 (1.8-2.4) μm. A novel Myxobolus sp., Myxobolus machidai sp. n., is described from a spotted knifejaw (Oplegnathus punctatus) fished in the Sea of Japan, off Shimonoseki, Yamaguchi Prefecture, Japan. Plasmodia were embedded in the esophageal wall. Its round spore was small in size, 9.0 (8.1-9.4) μm in length, 7.8 (7.5-8.3) μm in width, and 5.5 (5.1-6.0) μm in thickness. It contained two polar capsules, 3.5 (3.2-3.8) × 2.3 (2.2-2.5) μm. Spore development in a plasmodium was asynchronous. Nucleotide sequencing of the small subunit ribosomal RNA gene (SSU rDNA) of these two novel Henneguya spp. revealed a close phylogenetic relationship with the marine clade of Henneguya spp.; however, they were distinct in morphology and SSU rDNA sequence from any known species. M. machidai sp. n. was grouped with freshwater Henneguya spp. in a phylogenetic tree based on the SSU rDNA, distant from a known marine clade of Myxobolus spp. reported mainly from the Mediterranean Sea. This is the first record of Henneguya-Myxobolus spp. from natural marine water in Japan.
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    ABSTRACT: We describe a new species of myxozoan, Henneguya mauritaniensis n. sp., extracted from the arterial bulb of the bluespotted seabream, Pagrus caeruleostictus (Valenciennes, 1830), collected in Mauritanian waters. Out of the 209 individuals examined, 30.1 % were infected with this new taxon. Spore total length ranged from 15.0 to 20.5 μm with a mean of 17.9 μm. The two polar capsules were equal in size, and pyriform and caudal appendages joined until mid-length. Morphometric analysis revealed significant differences between H. mauritaniensis n. sp. and morphologically similar species from this region as well as congeners known from other sparid hosts. Phylogenetic analysis of 18 S rDNA indicated that this new species is closely related to Henneguya pagri, reported recently from Pagrus major off Japan. Bayesian inference and maximum likelihood analyses of the 18 S rDNA dataset also revealed that species of marine Henneguya reported forming pseudocysts in the hearts of their fish hosts were closely related. Histological analysis of the H. mauritaniensis n. sp. pseudocysts embedded in the arterial bulb of P. caeruleostictus suggests that these parasites may cause considerable pathology, which may impact negatively on the health of the fish host. Finally, we discussed the importance of a combination of morphological and molecular analysis for species description because of high variability in size within the same taxa.
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