Georges Bouix

Philasterides dicentrarchi, n. sp., (ciliophora, scuticociliatida), a histophagous opportunistic parasite of Dicentrarchus labrax (Linnaeus, 1758), a reared marine fish

Summary In sea bass Dicentrarchus labrax (L.) reared in the Mediterranean sea, mortality suddenly arose. The diseased fishes, noticeable when almost dead, were massively infested with a histophagous ciliate. Depending on the infected host organs, the ciliate showed in its food vacuoles various categories of ingested cells: erythrocytes, ovocytes, and others. The infecting mode of this presumed “parasite” is still unknown, all experimental infections having failed. Morphological, biometric and ultrastructural studies lead to the conclusion that, because of its morphological characteristics and its main stomatogenesis processes, this ciliate is a Scuticociliatida Philasterina. Compared to other known species, it differs by its small size, the small and regular number of its somatic kineties, the position of its buccal organelles (and, mainly, the bipartite paroral membrane), the presence of two types of extrusomes, and a perinuclear envelope. All these characteristics justify the creation of a new species: Philasterides dicentrarchi. This particular ciliate habitat is compared to that of other commensal or opportunistic parasitic ciliates of invertebrates and marine fishes.

Myxosporea (Protozoa: Myxozoa) of freshwater fishes in Africa: keys to genera and species

In Africa, about a hundred species of Myxosporea are known to infest fishes in various countries. Species of nine genera have been described in freshwater fishes: Myxidium, Sphaerospora, Myxobilatus, Myxobolus, Thelohanellus, Unicauda, Henneguya, Chloromyxum and Kudoa. In the present note, we propose a key to the species infecting freshwater fishes. A systematic revision of some species is given. A list of different species, their hosts and their geographical distribution are also presented.

Loma camerounensis sp. nov. (Protozoa: Microsporida) a parasite ofOreochromis niloticus Linnaeus, 1757 (Teleost: Cichlidae) in fish-rearing ponds in Melen, Yaoundé, Cameroon

A new microsporidian,Loma camerounensis, was found in the CichlidaeOreochromis niloticus from the Melen fish-rearing station in Yaoundé, Cameroon. Xenomas were located in the gut from the oesophagus to the intestine, but preferentially in the duodenum. Dimensions of the fresh spores were 3.96×2.16 μm. The ultrastructural study indicated the following characteristics: parasite stages arranged in a random, unstratified manner in the xenoma; merogony by multiple fission; sporogonic stages isolated within a sporophorous vesicle containing several sporoblasts and polysporoblastic sporogony. Ultimately the spores appeared to be isolated in a single vesicle, but this was a secondary phenomenon induced by the intervention of tubules that resolved in partitions of the initial sporophorous vesicle.

Microsporidiosis on Artemia (Crustacea, Anostraca): light and electron microscopy of Vavraia anostraca sp. nov. (Microsporidia, Pleistophoridae) in the Brazilian solar salterns

Abstract A high prevalence of microsporidiosis was detected in an extensive culture of Artemia in two Brazilian solar salterns. The disease was responsible for the disruption of both the eggs and the biomass production. The main microsporidian is primarily a muscular parasite, with pansporoblastic development. All stages presented isolated nuclei. In merogonial stages, the amorphous coat divided with the cell, whereas in the sporogonial plasmodia the protoplasm retracted away from the coat, producing the vesicule cavity. Sporogonial division occurred both stepwise and by rosette-shape fragmentation. The number of nuclei in mature sporonts was variable and sometimes exceeded 64. As the sporophorous vesicle became mature, the matrix was occupied by metabolic granular products that became tubular. Microspores (3.3 × 2.1 μm) and macrospores (4.1 × 2.7 μm) were observed. The number of coils of the anisofilar filament was 11 (microspores) and 15 (macrospores). The ultrastructure and cytology of the parasite revealed that it was a new species: Vavraia anostraca sp. nov. For the first time a species of Vavraia is described in crustaceans. The taxonomy is discussed.

Ultrastructural Study of Endoreticulatus durforti N. Sp., a New Microsporidian Parasite of the Intestinal Epithelium of Artemia (Crustacea, Anostraca)

ABSTRACT. A new microsporidian parasite of the Artemia intestinal epithelium has been studied. The microsporidium developed within a membranous parasitophorous vesicle from the host rough endoplasmic reticulum consisting of two membranes, with the proximal one usually lacking ribosomes.

Ultrastructure and development of Neonosemoides tilapiae (Sakiti and Bouix, 1987) n.g., n. comb. (Protozoa, microspora) from African Cichlid fish

Summary Neonosemoides tilapiae n.g., n. comb., previously described in Cichlid fish (Sarotherodon melanotheron, Tilapia guineensis and T. zillii) from Benin, was found in Tilapia guineensis caught in Senegal and studied with the electron microscope. All developmental stages were in direct contact with the host-cell cytoplasm. The life cycle had two merogonial phases and one sporulation sequence. Nuclei were paired as diplokarya throughout the first merogony and were unpaired throughout the second merogony and the sporogony. Meronts were surrounded by a thin plasma membrane and their division occurred by binary fission or by plasmotomy. Sporogonial plasmodia were surrounded by a thick electrondense wall and divide by multiple fission into numerous uninucleate sporoblasts. Meiosis was not observed. The spores were uninucleate, pyriform and had anisofilar polar filament and lamellar polaroplast. A new genus, Neonosemoides, and a new family, Neonosemoidiidae, were created to contain this species, which became Neonosemoides tilapiae ( Sakiti and Bouix, 1987 ) n.g., n. comb.

Nosema manierae sp.n., Microsporidie parasite deChilo zacconius Blezenski 1970 (Lepidoptera: Pyralidae), hôte naturel, etHeliothis armigera (Hübner 1808) (Lepidoptera: Noctuidae), hôte expérimental: Cycle évolutif et ultrastructure

Nosema manierae sp.n. was first isolated from larvae ofChilo zacconius, then easily transmitted to the corn earworm,Heliothis armigera. In the two lepidopterans, the microsporidian causes a general infection and is highly pathogenic. The life cycle includes binucleate and quadrinucleate meronts and sporonts that divide to form binucleate (diplokaryotic) sporoblasts, typical of the genusNosema. All stages ofN. manierae were studied with the electron microscope.RésuméNosema manierae n. sp. a été découverte dans les larves deChilo zacconius, puis transmise àHeliothis armigera. Dans les deux Lepidoptères, la Microsporidie provoque une infection généralisée et est fortement pathogène. Le cycle de développement comprend des mérontes binucléés et tétranucléés et des sporontes qui se divisent pour donner des sporoblastes binucléés (diplokaryon), typiques du genreNosema. Tous les stades deNosema manierae ont été étudiés en microscopie électronique.

Isolation and partial characterization of IgM-like seabass (Dicentrarchus labrax L. 1758) immunoglobulins

Abstract An IgM-like immunoglobulin from seabass, Dicentrarchus labrax , has been one-step purified and partially characterized using gel filtration and polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS). The whole molecule has an approximate molecular weight of 883 kD, determined by gel filtration.

Nosema galerucellae n. sp., microsporidian (Protozoa, Microspora), parasite of Galerucella luteola Müller (Chrysomelidae, Coleoptera): development cycle and ultrastructure

The life cycle of the microsporidian parasite of Galerucella luteola (Chrysomelidae, Coleoptera) was investigated by optical and electron microscopy. All stages were diplokaryotic and apansporoblastic. Sporogony was disporous. Spores were oval, elongated and measured 4.95 × 2.89 μm with a lamellar polaroplast and 7-9 coils of polar filament. These ultrastructural features indicate that this microsporidian is a Nosema. We have named it Nosema galerucellae n. sp.

On the Cytology and Development of Loma boopsi n. sp. (Microspora, Glugeidae), Parasite of Boops boops (Pisces, Teleostei, Sparidae) from the Coasts of Senegal

Summary Loma boopsi n. sp. was found in the liver, intestine and pyloric caeca of Boops boops inhabiting the coasts of Senegal. Its ultrastructural characteristics were elucidated. All developmental stages had isolated nuclei and occupied the xenoma without any particular stratification. The merogonial stages were in direct contact with the host-cell cytoplasm. The merogonial plasmodium divided by plasmotomy. Sporogony occurred in sporophorous vesicles and the sporogonial plasmodium divided by plasmotomy. Two morphological types of spores were produced in the same sporophorous vesicle: ovoid spores measuring 3.70 × 2.40 µm and elongate, slightly incurvated spores which were 4.80 × 2.40 µm. They had a thick envelope (about 70 nm), a polaroplast with an anterior lamellar part and a posterior vesicular part, an isofilar polar filament displaying 12–14 (ovoid spores) or 16–18 (elongate spores) spiral turns in a single row of coils and a large posterior vacuole