THE LOBSTER PARASITE ANOPHRYOIDES HAEMOPHILA (SCUTICOCILIATIDA, ORCHITOPHRYIDAE) - NUCLEAR 18S RDNA SEQUENCE, PHYLOGENY AND DETECTION USINGOLIGONUCLEOTIDE PRIMERS

We have determined the nucleotide sequence of the nuclear gene encodin g small-subunit ribosomal ribonucleic acid of the ciliate Anophryoides haemophila, a parasite of the American lobster Homarus americanus. Th e gene is 1763 bp in length, and has a guanosine-plus-cytosine content of 43.9%. Inferred phylogenetic frameworks strongly support the monop hyly of the scuticociliates, and suggest that order Scuticociliatida s hould be elevated to at least subclass rank. Oligonucleotide probes ba sed on A. haemophila ssu-rDNA can discriminate between DNAs of A. haem ophila and other investigated hymenostome ciliates, and effectively pr ime polymerase chain reaction-based detection of A. haemophila deoxyri bonucleic acid against at least a 1600-fold excess of total deoxyribon ucleic acid from H. americanus.