Abstract: Methods for the controllable expression in high yields of heterologous proteins under the control of a modified tryptophan promoter-operator system are disclosed. The system employed involves sequential resort to tryptophan repression and derepression, as well as deletion of an attenuator function native to the tryptophan operon. Means are also disclosed for effecting deletions at any given point within a gene fragment and for the ready identification of transformant bacteria via triple ligation procedures.

Abstract: The present invention provides recombinant DNA vehicles which are suitable for the microbial expression of DNA encoding a heterologous polypeptide which comprises a portion of the trp operon having the promoter-operator and leader ribosome binding site, and a restriction site providing an insertion site for the DNA sequences encoding the heterologous polypeptide, wherein the restriction site is located 3' of the leader ribosome binding site as a substitute for the Taq I site of the trp promoter-operator and is selected from the group consisting of Xba I and Eco RI. Also provided are E. coli strains transformed with the above described recombinant DNA vehicles.

Abstract: A variety of processes for recovering gold from gold ore are disclosed. Briefly, the methods include culturing at least one microorganism species capable of producing cyanide ion under conditions wherein the microorganism produces cyanide ion, thus forming a cyanide ion-containing culture; contacting the cyanide ion-containing culture with gold ore, causing production of gold ion-cyanide ion complexes and biosorption of said complexes to said cultures; and recovering gold from the culture. The invention may be practiced with a variety of microorganisms, including Chromobacterium violaceum and Chlorella vulgaris.

Abstract: A variety of processes for recovering gold from gold ore are disclosed. Briefly, the methods include culturing at least one microorganism species capable of producing cyanide ion under conditions wherein the microorganism produces cyanide ion, thus forming a cyanide ion-containing culture; contacting the cyanide ion-containing culture with gold ore, causing production of gold ion-cyanide ion complexes and biosorption of said complexes to said cultures; and recovering gold from the culture. The invention may be practiced with a variety of microorganisms, including Chromobacterium violaceum and Chlorella vuloaris.

Abstract: A variety of processes for recovering gold from gold ore are disclosed. Briefly, the methods include culturing at least one microorganism species capable of producing cyanide ion under conditions wherein the microorganism produces cyanide ion, thus forming a cyanide ion-containing culture; contacting the cyanide ion-containing culture with gold ore, causing production of gold ion-cyanide ion complexes and biosorption of said complexes to said cultures; and recovering gold from the culture. The invention may be practiced with a variety of microorganisms, including Chromobacterium violaceum and Chlorella vulgaris.

Abstract: A variety of processes for recovering gold from gold ore are disclosed. Briefly, the methods include culturing at least one microorganism species capable of producing cyanide ion under conditions wherein the microorganism produces cyanide ion, thus forming a cyanide ion-containing culture; contacting the cyanide ion-containing culture with gold ore, causing production of gold ion-cyanide ion complexes and biosorption of said complexes to said cultures; and recovering gold from the culture. The invention may be practiced with a variety of microorganisms, including Chromobacterium violcaceum and Chlorella vulgaris.

Abstract: A method of altering double stranded DNA comprising converting double stranded DNA to single stranded DNA in a region surrounding a selected cleavage site, hybridizing a complimentary primer to the single stranded region formed in the previous step, and restoring enzymatically the second strand which had been eliminated.

Abstract: Disclosed herein are methods and means for microbially expressing human influenza hemagglutinin proteins, useful in the preparation of vaccines, by recombination of DNA gene sequences coding for hemagglutinin protein with microbially operable promoter-operator DNA and transformation of microbial host therewith.