Escherichia coli (E. coli) is a normal inhabitant of the gastrointestinal tract of vertebrates, including humans. Phylogenetic analysis has shown that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D). Group A and B1 are generally associated with commensals, whereas group B2 is associated with extra-intestinal pathotypes. Most enteropathogenic isolates, however, are assigne...

Structural alterations in DNA can serve as natural impediments to replication fork stability and progression, resulting in DNA damage and genomic instability. Naturally occurring polypurine mirror repeat sequences in the human genome can create endogenous triplex structures evoking a robust DNA damage response. Failures to recognize or adequately process these genomic lesions can result in loss...

Triplexes (triple helices) formed within DNA templates prior to or during DNA synthesis cause DNA polymerase to terminate [Samadashwily et al., EMBO J. 13 (1993) 4975-4983]. Here, we show that triplex-forming oligodeoxyribonucleotides (oligos) efficiently trap DNA polymerases at target DNA sequences within single-stranded (ss) templates. This was observed for all studied DNA polymerases, includ...

In the last decade, increased efforts have been directed toward the development of oligonucleotide-based technologies for genome analyses, diagnostics, or therapeutics. Among them, an antigene strategy is one promising technology to regulate gene expression in living cells. Stable triplex formation between the triplex-forming oligonucleotide (TFO) and the target double-stranded DNA (dsDNA) is f...

MOTIVATION Current methods for identification of potential triplex-forming sequences in genomes and similar sequence sets rely primarily on detecting homopurine and homopyrimidine tracts. Procedures capable of detecting sequences supporting imperfect, but structurally feasible intramolecular triplex structures are needed for better sequence analysis. RESULTS We modified an algorithm for detec...

Foodborne pathogens pose risks to populations all over the world. Pathogens can be used as bioterrorism agents, causing an outbreak that affects many individuals through consumption of a commonly affected food or beverage. A PCR assay identify their unique melting points using high-resolution melt assay. Assays detect bacteria individually from mixture species-specific primers. An was developed...

Phylogenetic analysis has shown that Escherichia coli is composed of four main phylogenetic groups (A, B1, B2 and D). Characterization of phylogenetic groups is of clinical interest, as group A and B1 generally associated with commensals, whereas most enteropathogenic isolates are assigned to group D, and group B2 is associated with extra-intestinal pathotype. One hundred E. coli strains recove...

We classify all connected, simple, 3-regular graphs with girth at least 5 that are Ricci-flat. use the definition of Ricci curvature on given in Lin-Lu-Yau, Tohoku Math., 2011, which is a variation Ollivier, J. Funct. Anal., 2009. A graph Ricci-flat, if it has vanishing edges. show, only Ricci-flat cubic Petersen graph, Triplex and dodecahedral graph. This will correct classification Comm. Anal...

The interaction of ethidium, a DNA intercalator, with the poly(dA).poly(dT) duplex and the poly (dA).2poly(dT) triplex has been investigated by a variety of spectrophotometric and hydrodynamic techniques. The fluorescence of ethidium is increased when either the duplex or triplex form is present. Binding constants, determined from absorbance measurements, indicate that binding to the triple hel...

Peptide nucleic acids (PNAs) have been developed for applications in biotechnology and therapeutics. There is great potential in the development of chemically modified PNAs or other triplex-forming ligands that selectively bind to RNA duplexes, but not single-stranded regions, at near-physiological conditions. Here, we report on a convenient synthesis route to a modified PNA monomer, thio-pseud...