Recent developments in bisintercalator natural products

The bisintercalator natural products are a family of nonribosomal peptides possessing a range of biological properties that include antiviral, antibiotic, and anticancer activities. The name bisintercalator is derived from the ability to directly bind to duplex DNA through two planar intercalating moieties. Although 19 members of this family of compounds have been identified over the past 50 years, the biosynthetic genes responsible for the formation of four of these molecules (thiocoraline, SW-163, triostin A, and echinomycin) were identified only recently. This recent progress opens an avenue towards understanding how Nature produces these bisintercalating products and provides the potential to develop and identify novel potent analogous lead compounds for clinical applications. This review discusses the mode of action of bisintercalators and summarizes recent genetic and biochemical insights into their biosynthetic production, analog formation, and possible mechanisms by which resistance to these compounds is achieved by their producing organisms. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 777–790, 2010.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77426/1/21489_ftp.pd

Convex Drawing for c-Planar Biconnected Clustered Graphs

In a graph, a cluster is a set of vertices, and two clusters are said to be non-intersecting if they are disjoint or one of them is contained in the other. A clustered graph is a graph with a set of non-intersecting clusters. In this paper, we assume that the graph is planar, each non leaf cluster has exactly two child clusters in the tree representation of non-intersecting clusters, and each cluster induces a biconnected subgraph. Then we show that such a clustered graph admits a drawing in the plane such that (i) edges are drawn as straight line segments with no crossing between two edges, and (ii) the boundary of the biconnected subgraph induced by each cluster is convex polygon