Patents by Inventor Frans A. Krens

Frans A. Krens has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Process for the in-vitro transformation of plant protoplasts with plasmid DNA
    Patent number: 4684611
    Abstract: Genetic properties of higher plants are transformed by incubating protoplasts of the plants together with plasmid DNA. The incubation is effected in the presence of polyethylene glycol and calcium ions. Subsequently--during after-incubation--the calcium ion concentration in the incubation medium is gradually increased and at the same time the polyethylene glycol concentration is decreased. The resulting aggregates are separated, grown further separately, and examined for modification of their genetic properties.
    Type: Grant
    Filed: July 29, 1985
    Date of Patent: August 4, 1987
    Assignees: Rijksuniversiteit Leiden, Robbert Schilperoort
    Inventors: Robbert A. Schilperoort, Frans A. Krens, George J. Wullems