Morphologic and Molecular Description of \u3cem\u3eMetopus fuscus\u3c/em\u3e Kahl from North America and New rDNA Sequences from Seven Metopids (Armophorea, Metopidae)

Most species in the large ciliate genus Metopus Claparède & Lachmann, 1858 lack detailed descriptions based on modern morphologic and molecular methods. This lack of data for the vast majority of species hampers application of a morphospecies approach to the taxonomy of Metopus and other armophorids. In this report we redescribe the large species, Metopus fuscus Kahl, 1927 based on in vivo observation, silver impregnation, scanning electron microscopy, and single-cell 18S rDNA sequencing of a freshwater North American (Idaho) population. Metopus fuscus invariably has a perinuclear envelope of endosymbiotic bacteria not found in other species. Unlike the original description of a single row of coarse granules between ciliary rows, the Idaho population has five loose rows of small interkinetal granules. We discuss the possible importance of this character in metopids. We also provide a phylogenetic analysis including seven other new metopid 18S rDNA sequences: Brachonella spiralis, B. galeata, Metopus laminarius, M. setosus, M. striatus, M. violaceus, Palmarella lata. Metopus fuscus and M. setosus form a fully supported clade, challenging previous morphospecies groupings. We discuss some ambiguities of armophorid morphologic terminology in the earlier literature. Our phylogenetic analysis of Idaho metopids indicates that the genera Metopus and Brachonella are both nonmonophyletic

An ELISA technique for rapid diagnosis of vibriosis in sea bass Dicentrarchus labrax

Three batches of rabbits were immunized against 2 strains of Vibrio anguillarum (Va V 62 and Va V 408), which cause vibriosis in sea bass Dicentrarchus labrax (L. 1758) Serranidae. Homologous and heterologous reactions were obtained against these Vibrio strains and other bacteria using an improved indirect ELISA technique. Antibody and antigen titrations revealed high immunogenecity (high antibody titers for the antisera) of the 2 Vibrio strains. They correspond to serotype I and show close affinity. The specificity and sensitivity of 1 selected antiserum were tested on brain extracts from healthy sea bass and those infected artificially with V. anguillarum serotypes I and III. Preliminary results confirm the reliability of the technique and warrant its use for improving disease diagnosis