title: Treatment of fish parasites. 11. Morphogenesis of Henneguya laterocapsulata Landsberg, 1987 (Myxosporea, Myxozoa), and the effects of a new triazine derivative, HOE 092 V, on its developmental stages: a light and electron microscopy study.
abstract: The ultrastructure of sporogenesis was studied in Henneguya laterocapsulata parasitizing the skin of hybrid catfish (Clarias gariepinus x Heterobranchus bidorsalis) in Nigeria. Sporogenesis started when a generative cell was surrounded by a second nondividing cell (i.e., envelope cell). By subsequent divisions of the generative cell, ten cells were produced, which finally became arranged into two spore-producing units. Each unit consisted of a binucleate sporoplasm, two capsulogenic cells, and two valvogenic cells. Apparently capsulogenesis, valvogenesis, and sporoplasm differentiation occurred concomitantly. In research for chemotherapy of fish parasitized by myxosporeans a new triazine derivative, 2-[3,5-alpha-dichloro-4-(4-methyl-sulfonylphenoxy)-phenyl]-1-me thy l- hexahydro-1,2,4-triazine-3,5-dion (HOE 092 V), was tested in vivo against the uni- and multicellular developmental stages of H. laterocapsulata. Naturally infected catfish were incubated in water containing 0, 2.5, 5, and 10 micrograms HOE 092 V/ml or the pure solvent for 3 h. After the fish had been returned into fresh water, they were killed 1 day after the treatment and the plasmodia were studied by means of light and transmission electron microscopy. Starting with a dose of 2.5 micrograms HOE 092 V/ml, the pericyte's outer membrane was broken in the bi- and multicellular stages. The number of ribosomes in the bi- and multicellular stages decreased. In the multicellular stages the rough endoplasmic reticula of the capsulogenic cells were enlarged. Treatment with 5 micrograms HOE 092 V/ml led to breaks in the limiting outer membranes of the capsulogenic cells and to vacuolization of their peripheral cytoplasm. In early prespore stages a decrease in the number of spherical inclusions was recognized.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Lehrstuhl für Spezielle Zoologie und Parasitologie Ruhr-Universität Bochum, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Schmahl
authors.forename: A
authors.initials: A
authors.lastname: Obiekezie
authors.forename: W
authors.initials: W
authors.lastname: Raether
mesh_terms: D000818:Animals; D002397:Catfishes / Q000469:parasitology*; D056890:Eukaryota / Q000187:drug effects* / Q000254:growth & development* / Q000648:ultrastructure; D005393:Fish Diseases / Q000188:drug therapy; D009024:Morphogenesis; D011528:Protozoan Infections / Q000188:drug therapy; D014227:Triazines / Q000627:therapeutic use*
chemical_list: D014227:Triazines; C079115:Hoe 092 V