Whole-Genome Sequences of Phages p000v and p000y, Which Infect the Bacterial Pathogen Shiga-Toxigenic Escherichia coli.

We report here the genome sequences and morphological characterizations of phages p000v and p000y, which infect the bacterial pathogen Shiga-toxigenic Escherichia coli O157:H7 and which are potential candidates for phage therapy against such pathogens.

Fighting Fire with Fire: Phage Potential for the Treatment of E. coli O157 Infection.

Hemolytic⁻uremic syndrome is a life-threating disease most often associated with Shiga toxin-producing microorganisms like Escherichia coli (STEC), including E. coli O157:H7. Shiga toxin is encoded by resident prophages present within this bacterium, and both its production and release depend on the induction of Shiga toxin-encoding prophages. Consequently, treatment of STEC infections tend to be largely supportive rather than antibacterial, in part due to concerns about exacerbating such prophage induction. Here we explore STEC O157:H7 prophage induction in vitro as it pertains to phage therapy-the application of bacteriophages as antibacterial agents to treat bacterial infections-to curtail prophage induction events, while also reducing STEC O157:H7 presence. We observed that cultures treated with strictly lytic phages, despite being lysed, produce substantially fewer Shiga toxin-encoding temperate-phage virions than untreated STEC controls. We therefore suggest that phage therapy could have utility as a prophylactic treatment of individuals suspected of having been recently exposed to STEC, especially if prophage induction and by extension Shiga toxin production is not exacerbated.

Molecular beam-controlled nucleation and growth of vertically aligned single-wall carbon nanotube arrays.

The main obstacle to widespread application of single-wall carbon nanotubes is the lack of reproducible synthesis methods of pure material. We describe a new growth method for single-wall carbon nanotubes that uses molecular beams of precursor gases that impinge on a heated substrate coated with a catalyst thin film. In this growth environment the gas and the substrate temperature are decoupled and carbon nanotube growth occurs by surface reactions without contribution from homogeneous gas-phase reactions. This controlled reaction environment revealed that SWCNT growth is a complex multicomponent reaction in which not just C, but also H, and O play a critical role. These experiments identified acetylene as a prolific direct building block for carbon network formation that is an order of magnitude more efficient than other small-molecule precursors. The molecular jet experiments show that with optimal catalyst particle size the incidence rate of acetylene molecules plays a critical role in the formation of single-wall carbon nanotubes and dense vertically aligned arrays in which they are the dominant component. The threshold for vertically aligned growth, the growth rate, the diameter, and the number of walls of the carbon nanotubes are systematically correlated with the acetylene incidence rate and the substrate temperature.