Abstract: Ricin B muteins, ricin and ricin precursors having at least one amino acid of at least one galactoside binding site altered to decrease the binding of ricin B to galactosides are claimed. DNA sequences encoding the ricin B muteins, ricin and ricin precursor in which the B chain thereof is the ricin B mutein are claimed. Recombinant expression vectors effective in expressing the DNA sequences of the ricin B muteins, ricin and ricin precursors are claimed. Host cells transformed with the foregoing expression vectors are also claimed. Conjugates comprising binding moieties such as antibodies, hormones, and lymphokines bound to the ricin B mutein and ricin wherein the B chain thereof is the mutein is also claimed.

Abstract: An assay method for the detection of a specific nucleotide target sequence in a polynucleotide test extract is disclosed which utilizes a polynucleotide modified probe including both a cDNA sequence substantially complementary to the specific target sequence and a protein binding sequence. The assay is conducted by exposing the modified probe to the polynucleotide test extract for hybridization and then exposing the complex to the protein which binds to the protein binding sequence. An assay, such as an immunoassay, can then be conducted on the test sample to indicate the presence of the specific target sequence by detecting the presence of the binding protein.

Abstract: A culture medium and method for the isolation and culture of plant protoplasts is disclosed which includes in it a quantity of neutral mammalian blood serum. An addition of 1 to 25% serum to protoplast media results in a greater yield of viable protoplast cells, helps to protect the protoplasts in culture, and makes it possible to obtain and maintain corn protoplasts, a heretofore difficult task.