Showing papers by "George M. Weinstock published in 1987"

Temporal control of colicin E1 induction.

Abstract: The expression of the gene encoding colicin E1, cea, was studied in Escherichia coli by using cea-lacZ gene fusions. Expression of the fusions showed the same characteristics as those of the wild-type cea gene: induction by treatments that damage DNA and regulation by the SOS response, sensitivity to catabolite repression, and a low basal level of expression, despite the presence of the fusion in a multicopy plasmid. Induction of expression by DNA-damaging treatments was found to differ from other genes involved in the SOS response (exemplified by recA), in that higher levels of DNA damage were required and expression occurred only after a pronounced delay. The delay in expression following an inducing treatment was more pronounced under conditions of catabolite repression, indicating that the cyclic AMP-cyclic AMP receptor protein complex may play a role in induction. These observations also suggest a biological rationale for the control of cea expression by the SOS response and the cyclic AMP-cyclic AMP receptor protein catabolite repression system.

Pharmaceutical compositions of a 105 kD P. Haemolytica derived antigen useful for treatment of Shipping Fever

Abstract: Novel compositions are disclosed for use in the treatment or diagnosis of bovine pasteurellosis, commonly referred to as Shipping Fever. Cell-free Pasteurella haemolytica supernatants are employed to provide individual antigen compositions, identified through reaction with sera from naturally-infected or convalescent cattle. In particular, at least seven individual P. hameolytica antigen groups were recognized in cell-free culture supernatants. Purified P. haemolytica supernatant, formulated in a suitable pharmaceutical vaccine composition is shown to elicit a specific immune response, in both cows and rabbits, directed against the individual immunoreactive P. haemolytica polypeptides identified. Also disclosed are novel recombinant cells, plasmids and bacteriophage which include transcriptionally active P. haemolytica antigen genes. Recombinant clones are similarly selected to be reactive with naturally-infected antisera. Examples, and further disclosure, are also provided which demonstrate the utility of a presently disclosed antibody and antigen compositions in immunodetection of both antigens and antibodies in various biological samples.

Use of open reading frame expression vectors.

Abstract: Publisher Summary This chapter discusses the use of open reading frame (ORF) vectors that contain the outer membrane protein (ompF) initiator region. Several other vectors have been developed that use other initiator regions for expression but are otherwise analogous in the use of β-galactosidase to monitor expression. The ompF vectors provide a convenient test for proper inserts (overproduction lethality) and an as yet untested possibility for increased tribrid protein stability due to export from the cytoplasm. ORF vectors have also found other applications beside the production of antibodies. When the initiator region in the tribrid gene is replaced with the 5’ end of the foreign sequence, theβ-galactosidase activity of the resulting lac operon z (lacZ) gene fusion can be used to optimize expression in E. coli from the foreign gene's initiation sequences. Then, replacement of the lacZ region with the 3’ end of the foreign gene results in a vector capable of producing the intact foreign polypeptide in E. coli . In addition, the tribrid proteins have been used as a diagnostic tool to detect antibodies present in serum samples.