Phage activity

Exploratory studies using 18 different phages active on Salmonella serogroups A, B and D revealed that in effect all phages had hydrolytic activity and that all of them shared specificity for the L-Rhaj>(al 3)D-Galj> linkage (33, 36-38). There are, however, minor differences in terms of enzyme specificity. 

Lead citrate inhibited oxidative metabolism of mouse peritoneal macrophages exposed to macro-phage-activating factor (Buchmuller-Rouiller et al. 1989). 

P22 phage antibody neutralizes phage activity more efficiently than transducing activity. This is also true for inactivation by ultraviolet irradiation. 

Figure 17.10 Construction of a two helix truncated Z domain, (a) Diagram of the three-helix bundle Z domain of protein A (blue) bound to the Fc fragment of IgG (green). The third helix stabilizes the two Fc-binding helices, (b) Three phage-display libraries of the truncated Z-domaln peptide were selected for binding to the Fc. First, four residues at the former helix 3 interface ("exoface") were sorted the consensus sequence from this library was used as the template for an "intrafece" library, in which residues between helices 1 and 2 were randomized. The most active sequence from this library was used as a template for five libraries in which residues on the Fc-binding face ("interface") were randomized. Colored residues were randomized blue residues were conserved as the wild-type amino acid while yellow residues reached a nonwild-type consensus, [(b) Adapted from A.C. Braisted and J.A. Wells,...

Protein engineering is now routinely used to modify protein molecules either via site-directed mutagenesis or by combinatorial methods. Factors that are Important for the stability of proteins have been studied, such as stabilization of a helices and reducing the number of conformations in the unfolded state. Combinatorial methods produce a large number of random mutants from which those with the desired properties are selected in vitro using phage display. Specific enzyme inhibitors, increased enzymatic activity and agonists of receptor molecules are examples of successful use of this method. 

A. nidulans with selected phages of classes A, B, C, D and E resulted in increased polygalacturonase activity in comparison with the wild type strain. The culture media of pga transformants were further analysed by Western blotting with polyclonal antibodies raised against PGI and in all samples examined cross-reactive bands with molecular masses similar to that found for PGI or PGII were detected. 

Early infiltration of polymorphonuclear leukocytes and monocyte/macro-phages into the transplanted organ occurs soon after reperfusion of the transplant is initiated. In the context of transplantation, oxygen deprivation and general tissue stress of the graft leads to the activation of proinflammatory cytokines and the upregulation of the adhesion molecules required for leukocyte... 

Crameri, R., and Suter, M. (1993). Display of biologically active proteins on the surface of filamentous phages a cDNA cloning system for selection of functional gene products linked to the genetic information responsible for their production. Gene 137, 69-75. 

Lytic growth of Mu can occur either upon initial infection, if the c gene repressor is not formed, or by induction of a lysogen. In either case, replication of Mu DNA involves repeated transposition of Mu to multiple sites on the host genome. Initially, transcription of only the early genes of Mu occurs, but after gene C protein, a positive activator of late RNA synthesis, is expressed, the synthesis of the Mu head and tail proteins occurs. Eventually, expression of the lytic function occurs and mature phage particles are released. 

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