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N Stoker

Publications and source records attributed to N Stoker.

4 recordsLinked to original sources
PubMed1991

Screening gene expression libraries for epitopes recognized in Mycobacterium leprae by mouse T cells.

Parasite expression libraries have so far been screened with antibodies, DNA probes or T cell clones. Immunity to many parasites, such as Mycobacterium leprae, is largely mediated by T cells, and so the screening of such libraries for T cell epitopes is an important step toward the development of effective vaccines and diagnostic reagents. A new method for screening of lambda gt11 libraries with uncloned T cell populations is presented here, which takes advantage of the fact that the recombinant proteins contain beta-galactosidase as their leader peptide; this allows them to be semipurified by means of anti-beta-galactosidase antibodies coated on the bottom of microtiter plate wells, within which a proliferation assay can then be carried out. Optimum conditions for the assay were determined, using the M. leprae 18-kDa antigen as a test antigen.

Animals↗
PubMed1980

Defective and plaque-forming lambda transducing bacteriophage carrying penicillin-binding protein-cell shape genes: genetic and physical mapping and identification of gene products from the lip-dacA-rodA-pbpA-leuS region of the Escherichia coli chromosome.

A series of defective lambda transducing phage carrying genes from the lip-leuS region of the Escherichia coli chromosome (min 14 on the current linkage map) has been isolated. The phage defined the gene order as lac---lip-dacA-rodA-pbpA-leuS---gal. These included the structural genes for penicillin-binding protein 2 (pbpA) and penicillin-binding protein 5 (dacA) as well as a previously unidentified cell shape gene that we have called rodA. rodA mutants were spherical and very similar to pbpA mutants but were distinguishable from them in that they had no defects in the activity of penicillin-binding protein 2. The separation into two groups of spherical mutants with mutations that mapped close to lip was confirmed by complementation analysis. The genes dacA, rodA, and pbpA lie within a 12-kilobase region, and represent a cluster of genes involved in cell shape determination and peptidoglycan synthesis. A restriction map of the lip-leuS region was established, and restriction fragments were cloned from defective transducing phage into appropriate lambda vectors to generate plaque-forming phage that carried genes from this region. Analysis of the proteins synthesized from lambda transducing phage in ultraviolet light-irradiated cells of E. coli resulted in the identification of the leuS, pbpA, dacA, and lip gene products, but the product of the rodA gene was not identified. The nine proteins that were synthesized from the lip-leuS region accounted for 57% of its coding capacity. Phage derivatives were constructed that allowed about 50-fold amplification of the levels of penicillin-binding proteins 2 and 5 in the cytoplasmic membrane.

Bacterial Proteins↗