When I took “Metabolic and Biochemical Processes of Microorganisms” at UT Austin my professor Dr. Marvin Whiteley lectured on blue/white screening. In its fundamental form, the concept involved mutated E. coli that could no longer breakdown lactose because its “lacZ” gene was removed.
The bottom line is that DNA would be inserted into the mutated bacterial genome via transformation. Ultimately, mutated E.coli once the lacZ gene was inserted, would be able to produce the enzyme beta-galactosidase (responsible for the lactose breakdown). The enzymatic activity could be detected by using an organic compound known as “X-gal.” If the cells are grown in the presence of X-gal when the lacZ gene is translated into the beta-galactosidase the enzyme will catabolically cleave the X-gal, resulting in a blue colored cell. If the cells did not produce the enzyme, then the cells would be white. This classic experiment is sine quo non to the understanding of recombinant DNA.
In 1998, in the case Schering Corp. v. Amgen Inc. the United States District Court for the District of Delaware interpreted a patent regarding recombinant DNA. Dr. Charles Weissmann used recombinant DNA technology to amplify human-extracted interferon- [alpha]. When a white blood cell is exposed to a virus, the blood cell makes interferon, a protein that kills viruses. This protein also has anti-tumor activity. However, the human body does not create a large enough amount of the interferon so Dr. Weissmann sought to produce the interferon in higher quantity by amplifying the genetic code of the polypeptide using bacteria through DNA recombinant technology. Dr. Weissmann was the first person to identify and isolate the interferon- [alpha] genetic code. He filed for the 901 Patent for each DNA segment that coded for interferon- [alpha], the sequences that he himself identified and isolated.
The corporation the doctor worked for alleged that the defendant, Amgen Inc. infringed on its 901 Patent. Although the plaintiff claimed that Amgen infringed on its patent, Amgen claimed that the patent was invalid. The court was left to interpret the patent.
In a patent infringement case the court uses a two step analysis. First, the court must interpret the meaning of the patent, this is known as “claim construction.” Second, the court must compare the claim to the “accused product.” The court construed some of the words in favor the plaintiff, and others in favor of the defendant.
The significance of this case in the world of “Mircobiolawgical” is that it applies the concept of claim construction in a patent infringement case. Here, it is apparent that the way the patent is worded may affect how protected the discovery or invention will be.
For example, one of the issues was whether the term “consisting of” should be afforded a limited special meaning. The court found that words were inconsequential, and merely transitional. The court then did a step-by-step analysis of significant word listed in each claim.