Maturation of tumor vasculature by interferon-beta disrupts the vascular niche of glioma stem cells.

BACKGROUND: The vascular niche necessary for cancer stem cell maintenance is a potential target for cancer therapy. MATERIALS AND METHODS: Human glioma xenografts were treated with IFN-ß delivered systemically via a liver-targeted, adeno-associated viral vector. The vascular niche was examined with immunofluorescence for glioma stem cells, endothelial cells, and perivascular cells. RESULTS: Although IFN-ß was not directly toxic to glioma stem cells in vitro, IFN-ß decreased tumor size and the number of stem cells recovered in both heterotopic and orthotopic models. Treatment with IFN-ß increased perivascular cells investing the tumor vasculature (6-fold) distancing stem cells from endothelial cells. Additionally, vascular smooth muscle cells co-cultured between stem cells and endothelial cells decreased stem cell recovery. CONCLUSION: Continuous delivery of IFN-ß decreased the number of stem cells in glioma xenografts by disrupting the vascular niche through an increase in perivascular cells, which created a barrier between the glioma stem cells and the endothelial cells.

The use of 16S and 16S-23S rDNA to easily detect and differentiate common Gram-negative orchard epiphytes.

The identification of Gram-negative pathogenic and non-pathogenic bacteria commonly isolated from an orchard phylloplane may result in a time consuming and tedious process for the plant pathologist. The paper provides a simple "one-step" protocol that uses the polymerase chain reaction (PCR) to amplify intergenic spacer regions between 16S and 23S genes and a portion of 16S gene in the prokaryotic rRNA genetic loci. Amplified 16S rDNA, and restriction fragment length polymorphisms (RFLP) following EcoRI digestion produced band patterns that readily distinguished between the plant pathogen Erwinia amylovora (causal agent of fire blight in pear and apple) and the orchard epiphyte Pantoea agglomerans (formerly E. herbicola). The amplified DNA patterns of 16S-23S spacer regions may be used to differentiate E. amylovora at the intraspecies level. Isolates of E. amylovora obtained from raspberries exhibited two major fragments while those obtained from apples showed three distinct amplified DNA bands. In addition, the size of the 16S-23S spacer region differs between Pseudomonas syringae and Pseudomonas fluorescens. The RFLP pattern generated by HaeIII digestion may be used to provide a rapid and accurate identification of these two common orchard epiphytes.