Role of the Helicobacter pylori outer-membrane proteins AlpA and AlpB in colonization of the guinea pig stomach

The human gastric pathogen Helicobacter pylori expresses several putative outer-membrane proteins (OMPs), but the role of individual OMPs in colonization of the stomach by H. pylori is still poorly understood. The role of four such OMPs (AlpA, AlpB, OipA and HopZ) in a guinea pig model of H. pylori infection has been investigated. Single alpA, alpB, hopZ and oipA isogenic mutants were constructed in the guinea pig-adapted, wild-type H. pylori strain GP15. Guinea pigs were inoculated intragastrically with the wild-type strain, single mutants or a mixture of the wild-type and a single mutant in a 1: 1 ratio. Three weeks after infection, H. pylori could be isolated from stomach sections of all animals that were infected with the wild-type, the hopZ mutant or the oipA mutant, but from only five of nine (P = 0.18) and one of seven (P = 0.02) animals that were infected with the alpA or alpB mutants, respectively. The hopZ and oipA mutants colonized the majority of animals that were inoculated with the strain mixture, whereas alpA and alpB mutants could not be isolated from anim

Building predictable systems on chip: an analysis of guaranteed communication in the aethereal network on chip

As the complexity of Systems-on-Chip (SoC) is growing, meeting real-time requirements is becoming increasingly difficult. Predictability for computation, memory and communication components is needed to build real-time SoC. We focus on a predictable communication infrastructure called the Æthereal Network-on-Chip (NoC). TheÆthereal NoC is a scalable communication infrastructure based on routers and network interfaces (NI). It provides two services: guaranteed throughput and latency (GT), and best effffffort (BE). Using the GT service, one can derive guaranteed bounds on latency and throughput. To achieve guaranteed throughput, buffffffers in NI must be dimensioned to hide round-trip latency and rate difffffference between computation and communication IPs (Intellectual Property). With the BE service, throughput and latency bounds cannot be derived with guarantees. In this chapter, we describe an analytical method to compute latency, throughput and buffffffering requirements for the Æthereal NoC. We show the usefulness of the method by applying it on an MPEG-2 (Moving Picture Experts Group) codec example