Changes in the extracellular accumulation of antibiotics during growth and sporulation of Bacillus subtilis in liquid culture

An orthogonal active site identification system (OASIS) for proteomic profiling of natural product biosynthesis

A significant gap exists between genetics-based investigations of polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) biosynthetic pathways and our understanding of their regulation, interaction, and activity in living systems. To help bridge this gap, here we present an orthogonal active site identification system (OASIS) for the proteomic identification and analysis of PKS/NRPS biosynthetic enzymes. OASIS probes target conserved features of PKS/NRPS active sites to provide activity-based enrichment of modular synthases, followed by analysis through multidimensional protein identification technology (MudPIT) LC-MS/MS analysis. When applied to the model bacterium Bacillus subtilis, this functional proteomics method detects and quantifies all four modular synthases in the organism. Furthermore, tandem application of multiple OASIS probes enhances identification of specific PKS/NRPS modules from complex proteomic mixtures. By expanding the dynamic range of proteomic analysis for PKS/NRPS enzymes, OASIS offers a valuable tool for strain comparison, culture condition optimization, and enzyme discovery.

Occlusion and infection in Broviac catheters during intensive cancer therapy

Before administration of intensive cytotoxic therapy, 90 central venous catheters were inserted into 80 patients with malignancies. Twenty-seven episodes of bacteremia and fungemia occurred during 96 treatment courses. The majority of these infections were due to gram-positive bacteria (45%) or fungi (22%), although gram-negative organisms accounted for 33%. Catheter occlusion occurred in patients receiving intravenous phenytoin, but blood products could be infused without difficulty. An increase in gram-positive bacteremias in patients with these catheters and drug-induced catheter occlusion must now be appreciated.

Possible functions of peptide antibiotics during growth of producer organisms: bacitracin and metal (II) ion transport

The inhibitory effect of bacitracin upon growth of the producer strain Bacillus licheniformis ATCC 10716 was dependent upon the presence of several different metal (II) ions, particularly Mn (II), Co (II), or Zn (II) ions. This supports our previous suggestion that the normal function of bacitracin during growth of the producer organism may be to promote the uptake of several divalent metal ions. Due to the striking similarity between the antimicrobial effect of bacitracin towards susceptible organisms and the effect of bacitracin towards the producer organisms B. licheniformis ATCC 10716, the possibility that the antimicrobial effect of bacitracin may be an induction of uptake of toxic amounts of metal ions is discussed. The possibility that peptide antibiotics may normally participate in ion transport during growth of producer organisms is also discussed.