The ensuing contribution gives an insight into the evolution of non-coding ribosomal DNA of two distantly related groups of snails. The non-coding sequences of the ribosomal DNA comprise the First Internal Transcribed Spacer (ITS-1), the Second Internal Transcribed Spacer (ITS-2), and the NonTranscribed Spacer (NTS). These spacers are known to evolve faster than the coding 18S, 5.8S and 28S rib...

background: infection with ornithobilharzia turkestanicum has been reported in a wide ran ge of animals worldwide. this study was undertaken to assess the util-ity of polymerase chain reaction (pcr), for detecting the infection with o . turke-stanicum larvae stages in lymnaea gedrosiana . methods: a total of 6,759 lymnaeidae snails were collected from six aquatic habitats in west azarbaijan, no...

Physidae, a world-wide family of freshwater snails with about 80 species, are reclassified by progressive characters of the penial complex (the terminal male reproductive system): form and composition of penial sheath and preputium, proportions and structure of penis, presence or absence of penial stylet, site of pore of penial canal, and number and insertions of penial retractor muscles. Obser...

Trichobilharzia regenti is a neurotropic bird schistosome,causing cercarial dermatitis in humans. In this study, ZAP cDNA expression library from Radix peregra s. lat. hepatopancreases containing intramolluscan stages of T. regenti was constructed and screened using PCR with specific and degenerate primers, designed according to previously described serine and cysteine peptidases of other paras...