European patent 290986 is the most recently issued patent in this family. Claim 1 recites a phosphinothricin resistance gene obtained from bacteria that are not fungus-like. This description discloses a resistance gene from bacteria other than those specified in the dominant PGS patent. Although the broadest independent claim in the PGS patent covers, in principle, any microorganism, the specification teaches only so-called fungus-like bacteria — Streptomyces sp to be more precise — which belong to the gram-positive Actinomycetales family. Although there are many genera that are not fungus-like within the gram-positive group, the patent family discussed here lists only gram-negative bacteria in its dependent claims. Furthermore, only the genus Alcaligenes was granted in the claims of the corresponding U.S. patent (US 5077399; see below). Plants and propagules harboring the gene are also covered in the claims (see Claims 8 and 9). Claim 10 recites a novel application of the gene expressed in microorganisms, namely for degradation of sewage contaminated with phosphinothricin, which could be a useful way to clean up contamination.
The corresponding granted claims for Spain have also been included in the Appendix. These provide an example of how claims must be sometimes reformulated to comply with national legislation. Patenting of genes and plants is not allowed in Spain, but processes to generate or to select genes and transgenic plants are allowed.
As mentioned earlier, the U.S. patent in this family has a very narrow scope given the broad claims of the PGS patents. Claims are limited to a phosphinothricin resistance gene isolated from the genus Alcaligenes (Proteobacteria: beta subdivision). The peptide sequence of this enzyme is 33% identical to the homolog isolated from Streptomyces, and 53% similar in terms of conservative amino acid exchanges.
Transgenic plants containing the gene or other applications of the gene expressed in microorganisms (e.g. the treatment of phosphinothricin-contaminated sewage) are not included in the granted claims of this patent, although these possibilities are mentioned in the specifications.
The dominant claim in this patent has the form of a “product by process” claim, i.e. it follows the basic form “a product X obtained by carrying out process Y”. The question here is whether obtaining the same product using a different process would constitute infringement. In the United States this issue is yet to be considered at the Federal Circuit level. Meanwhile, some district courts are treating the sale or use of product X not produced by process Y as infringement. In the ongoing discussion by the courts, two issues are separated, i.e. determination of patentability and assessment of infringement. Patentability is dependent on novelty of the product. Inclusion of the process in the claims is allowed to facilitate the definition of the product (also contemplated by the European Patent Convention). Existing case law supports the notion that the scope was limited by the process stated. If this becomes the guiding principle, then, taking the above patent as an example, performing PCR on non-selected bacteria would not constitute an infringement of the patent.