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Article: Ultrastructural description of Ceratomyxa microlepis sp. nov. (Phylum Myxozoa): a parasite infecting the gall bladder of Hemiodus microlepis, a freshwater teleost from the Amazon River.
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ABSTRACT: A new ceratomyxid parasite was examined for taxonomic identification, upon being found infecting the gall bladder of Hemiodus microlepis (Teleostei: Hemiodontidae), a freshwater teleost collected from the Amazon River, Brazil. Light and transmission electron microscopy revealed elongated crescent-shaped spores constituted by two asymmetrical shell valves united along a straight sutural line, each possessing a lateral projection. The spores body measured 5.2 ± 0.4 µm (n = 25) in length and 35.5 ± 0.9 µm (n = 25) in total thickness. The lateral projections were asymmetric, one measuring 18.1 ± 0.5 µm (n = 25) in thickness and the other measuring 17.5 ± 0.5 µm (n = 25) in thickness. Two equal-sized subspherical polar capsules measuring 2.2 ± 0.3 µm in diameter were located at the same level, each possessing a polar filament with 5-6 coils. The sporoplasm was binucleate. Considering the morphometric data analyzed from the microscopic observations, as well as the host species and its geographical location, this paper describes a new myxosporean species, herein named Ceratomyxa microlepis sp. nov.; therefore representing the first description of a freshwater ceratomyxid from the South American region.Memórias do Instituto Oswaldo Cruz 04/2013; 108(2):150-4. · 2.15 Impact Factor -
Article: Histological survey of Pacific oysters Crassostrea gigas (Thunberg) in Galicia (NW Spain).
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ABSTRACT: In Galicia, there is an increasingly interest among representatives of the oyster industry in the development of Pacific oyster Crassostrea gigas culture. Nevertheless severe mortalities and emerging health problems in this species have been recently reported in European farming areas. A histological survey was performed from 2004 to 2009 to assess health status in both cultured and wild Galician oysters. Different symbiotic organisms and conditions were detected, including viral gametocytic hypertrophy (VGH) which is reported here for first time in Spanish coast. VGH, prokaryote-like colonies and ciliates were observed in oyster tissues without causing host damage. A haplosporidian infection, copepods inducing lesions and a cellular proliferative disorder were detected in some samples causing moderate host damage; their low prevalence suggests these parasites are not a threat for C. gigas in Galicia. None of the parasites detected is OIE (Office International des Epizooties: the World Organization for Animal Health) notifiable. Although the current study did not identify any pathogens or diseases of concern, it provides important prevalence baseline data for future health and epidemiological assessments needed to better understanding the existing and emerging health problems in this species.Journal of Invertebrate Pathology 09/2012; 111(3):244-51. · 2.06 Impact Factor -
Article: Myxobolus myleus n. sp. infecting the bile of the Amazonian freshwater fish Myleus rubripinnis (Teleostei: Serrasalmidae): morphology and pathology.
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ABSTRACT: Myxobolus myleus n. sp. is described from the gall-bladder of the freshwater fish Myleus rubripinnis collected near the city of Oriximiná in the Amazon System, Brazil. The spores obtained from the bile contained two equal symmetrical and smooth valves, each forming the spore wall. The spores were large, with a cone-like form, a semi spherical basal contour and measured (in μm) 19.3 ± 0.5 (n = 25) × 8.3 ± 0.5 (n = 25) × 4.0 ± 0.3 (n = 15). The apical end of the spores contained two elongate, equal and pointed conical polar capsules measuring 13.2 ± 0.4 μm (n = 25) in length and 3.0 ± 0.3 μm (n = 15) in width, each having a slightly tapering polar filament with 19 to 21 turns. The polar capsules were extended below at about 4/5 of the total length of the spores. The sporoplasm was binucleate and contained some sporoplasmosomes. All infected fish presented hypertrophy of the gall-bladder due to presence of the brownish parasite floating in the bile. In this paper we describe this new species of myxosporean based on light and ultrastructural observations, together with its associated pathology.Systematic Parasitology 07/2012; 82(3):241-7. · 1.25 Impact Factor -
Article: Ultrastructural characteristics of Nematopsis sp. oocysts (Apicomplexa: Porosporidae), a parasite of the clam Meretrix meretrix (Veneridae) from the Arabian Gulf, Saudi Arabia.
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ABSTRACT: This paper describes the fine structure of oocysts of Nematopsis sp. (Apicomplexa, Porosporidae) found in the abductor muscles of seawater clams, Meretrix meretrix (Linnaeus, 1758) (Veneridae), collected near the city of Dammam (6 degrees 17'0"N, 50 degrees 12'0"E) in the Arabian Gulf off the coast of Saudi Arabia. Oocysts of an ellipsoidal shape were found among myofibrils of the abductor muscles of infected clams. Each oocyst is composed of an oocyst wall surrounding a single uninucleate vermiform sporozoite located in the lumen of the oocyst wall. The thin oocyst wall (0.70-0.85 microm thick) is composed of homogenous electron-lucent material formed by three layers of equal-thickness. The oocyst wall contains a plano-convex opercular-like structure about 2.5 microm in diameter and 0.75-0.90 microm thick, composed of a homogenous material with moderate electron density. The oocyst is of an ellipsoidal shape and is 15.6 +/- 0.6 microm long and 11.1 +/- 0.7 microm wide. Externally, the oocyst wall is surrounded by a complex dense network of numerous anastomosed microfibrils, which are attached to the oocyst wall, forming 2-3 layers and extending towards the periphery, at some points penetrating amongst the host cells. The myofibrils in some cases show evident aspects of lysis as a consequence of the appearance of lysosome-like vesicles. Lacking knowledge of a complete life cycle and/or molecular data precluded the conclusive identification of this species.Folia parasitologica 06/2012; 59(2):81-6. · 1.81 Impact Factor -
Article: Ultrastructural aspects of Ellipsomyxa mugilis (Myxozoa: Ceratomyxidae) spores and developmental stages in Nereis diversicolor (Polychaeta: Nereidae).
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ABSTRACT: The ultrastructure of the spores and developmental stages of Ellipsomyxa mugilis in Nereis diversicolor were studied by transmission electron microscopy. The ultrastructure features and the developmental stages show many similarities with the general pattern described for other actinospores. However, several new features are definitely worth noting. For example, tetranucleated cells precede the formation of the initial pansporocyst, which preserves the 2 original enveloping cells until the end of sporogony. In the initial stages of sporogony, the future sporoplasm cell acquires the first secondary cell by an engulfment process. In the final stage of sporogony, spores are formed by a sporoplasm with 2 secondary cells and 1 somatic nucleus, and the polar capsule has a polar filament with a helicoidal arrangement possessing 7-8 coils.Journal of Parasitology 01/2012; 98(3):513-9. · 1.40 Impact Factor
