A microbial biosensor to predict bioavailable nickel in soil and its transfer to plants.

Ralstonia eutropha strain AE2515 was constructed and optimised to serve as a whole-cell biosensor for the detection of bioavailable concentrations of Ni2+ and Co2+ in soil samples. Strain AE2515 is a Ralstonia eutropha CH34 derivative containing pMOL1550, in which the cnrYXH regulatory genes are transcriptionally fused to the bioluminescent luxCDABE reporter system. Strain AE2515 was standardised for its specific responses to Co2+ and Ni2+.

Solid-phase enzyme immunoassay or radioimmunoassay for the detection of immune complexes based on their recognition by conglutinin: conglutinin-binding test. A comparative study with 125I-labelled Clq binding and Raji-cell RIA tests.

Bovine conglutinin was used in a solid-phase assay for the detection of immune complexes. In a first step, the tested serum sample is incubated in polypropylene tubes coated with conglutinin to allow C3-coated immune complexes to bind to solid-phase conglutinin. In a second step, the conglutinin-bound complexes are detected using an enzyme-conjugated or radiolabelled anti-immunoglobulin antibody.

Studies on immunoglobulins of Xenopus borealis, Xenopus clivii and Xenopus muelleri.

Following immunization with human IgG three species of anuran amphibians, Xenopus borealis, Xenopus clivii and Xenopus muelleri, were found to synthesize two molecular populations of antibodies associated with 19S and 7S fractions of the sera. These antibodies, designated high (HMW) and low (LMW) molecular weight immunoglobulins, were isolated and their constituent heavy (H) and light (L) polypeptide chains separated following extensive reduction and alkylation in a relative yield of about 70% and 30% respectively. The molecular weights of H and L chains of the three species were determined by SDS-acrylamide gel electrophoresis.