Abstract: A toxicant detection system comprises at least one watertight chamber containing a mollusk. Water to be screened is introduced into the chamber. The mollusk is preferably supported on a mounting structure which facilitates quick mounting of the mollusk in the device, comprising a releasable element affixed to the shell of the mollusk, e.g., a bolt which is screwed into a nut affixed to the mollusk's shell. A sensing apparatus is provided which includes a movable member supported in the chamber so that it engages the shell of the mollusk, and moves when the shell opens and closes. The sensing apparatus detects the position of the mollusk shell based on the position of the movable member. The sensing apparatus preferably includes a Hall effect transducer which co-acts with a magnet carried on the movable member.

Abstract: Provided in one embodiment is a non-infectious, recombinant hepadnavirus core particle composition comprising isolated hepadnavirus core particles, template RNA encapsidated in the same core particles and hepadnavirus polymerase encapsidated in the same core particles, wherein, upon addition of deoxynucleoside triphosphates to the composition, the hepadnavirus polymerase incorporates deoxynucleotides from the added deoxynucleosides into reverse transcripts of the template RNA beginning with the first deoxynucleotide of the reverse transcript or within about 10 deoxynucleotides of the first deoxynucleotide of the reverse transcript. Another embodiment provides hapadnaviral core particles with all three functional components: (1) P; (2) C; and (3) a nucleic acid that serves as a template.