Identification of a gene essential for O-acetylation of the Staphylococcus aureus type 5 capsular polysaccharide

It has been hypothesized that the developmental toxicity of certain compounds is, in part, due to maternal toxicity resulting in alterations in zinc (Zn) metabolism that affects the developing conceptus. In the present work the effects of developmentally toxic doses of 2-ethylhexanoic acid (EHXA), 2-ethylhexanol (EHXO), and valproic acid (VPA) on Zn metabolism were investigated in the pregnant rat. In experiment 1, dams were intubated with EHXA (3.13, 6.25, 9.38 or 12.5 mmol/kg), EHXO (6.25, 9.38 or 12.5 mmol/kg), VPA (1.56, 3.13, 6.25 or 9.38 mmol/kg), or corn oil (control; 1.0 ml/kg) at 14:00 h on gestation day (GD) 11.5, intubated with 32 microCi 65Zn at 22:00 h, and then killed at 08:00 h on GD 12.5. At the higher dose levels of EHXA and EHXO, and at all dosages of VPA, the percentage of 65Zn retained in maternal liver was higher, while that in the embryos was lower, than in controls. Chemical-associated changes in 65Zn distribution were associated with increased maternal liver metallothionein (MT) concentrations. In experiment 2, dams were fed diets containing 1, 25 or 97 microg Zn/g from GD 0-16 and intubated with 3.5 mmol EHXA or 1.0 ml corn oil/kg/d from GD 8-15. Dams were killed on GD 16 or 19. High incidences of encephalocele and tail defects were noted in the GD 16 fetuses of EHXA-treated dams fed either the low or adequate Zn diet, the highest incidences being in the low Zn group. On GD 19 the incidence of tail defects tended to be higher in the EHXA groups than in oil-treated controls, the highest incidence occurring in the low Zn EHXA group. Encephalocele was only observed in the low Zn EHXA-treated group. Fetal weight and crown-rump lengths were decreased by EHXA treatment and low dietary Zn. The incidence of rib anomalies was higher in the EHXA-exposed groups than in their respective oil controls. In experiment 3, GD 10.5 embryos collected from control dams were cultured for 48 h in serum from control or EHXA-treated male rats fed 4.5 or 25.0 microg Zn/g diets. Embryos cultured in either EHXA or low Zn sera exhibited delayed development; the addition of Zn to these sera eliminated their developmental toxicity. These results support the hypothesis that certain chemicals which induce maternal toxicity act, in part, to influence embryonic Zn metabolism and trigger abnormal development. Importantly, the teratogenic effects of these chemicals can be modulated by dietary Zn intake.     

Modern anti-Semitism and anti-Israeli attitudes.

Anti-Semitism is resurgent throughout much of the world. A new theoretical model of anti-Semitism is presented and tested in 3 experiments. The model proposes that mortality salience increases anti-Semitism and that anti-Semitism often manifests as hostility toward Israel. Study 1 showed that mortality salience led to greater levels of anti-Semitism and lowered support for Israel. This effect occurred only in a bogus pipeline condition, indicating that social desirability masks hostility toward Jews and Israel. Study 2 showed that mortality salience caused Israel, but no other country, to perceptually loom large. Study 3 showed that mortality salience increased punitiveness toward Israel’s human rights violations more than it increased hostility toward the identical human rights violations committed by Russia or India. Collectively, results suggest that Jews constitute a unique cultural threat to many people’s worldviews, that anti-Semitism causes hostility to Israel, and that hostility to Israel may feed back to increase anti-Semitism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The adhesion of thin plasma-polymerized organic films to metal substrates

The direct pull method was used to study the adhesion of thin (<1 μm) plasma-polymerized films on metal substrates. Application of this method provides information on the cohesive, as well as the adhesive, properties of these films. After breakage of the films by the pull method, the interface was analyzed by scanning electron microscopy to determine the nature of the breakage at the interface. Electron spectroscopy for chemical analysis was used to determine whether any chemically adsorbed layers of organic films remained after the films had been pulled from the metal substrate. The adhesive or cohesive strengths of plasma-polymerized tetrafluoroethylene and chlorotrifluoroethylene films on 304 stainless steel, aluminum and silver were measured by the pull method. Adhesive strength was found to be higher than cohesive strength for plasma-polymerized tetrafluoroethylene films on the various substrates. The result for plasma-polymerized chlorotrifluoroethylene films was not as expected, indicating that considerable care is required in the interpretation of tensile tests of laminates such as those conducted in this study.     

On the applicability of diploid genetic algorithms

The heuristic search processes like simple genetic algorithms help in achieving optimization but do not guarantee robustness so there is an immediate need of a machine learning technique that also promises robustness. Diploid genetic algorithms ensure consistent results and can therefore replace Simple genetic algorithms in applications such as test data generation and regression testing, where robustness is more important. However, there is a need to review the work that has been done so far in the field. It is also important to analyse the applicability of the premise of the dominance techniques applied so far in order to implement the technique. The work presents a systematic review of diploid genetic algorithms, examines the premise of the dominance relation used in different works and discusses the future scope. The work also discusses the biological basis of evaluating dominance. The work is important as the future of machine learning relies on techniques that are robust as well as efficient.     

Bacterial Cell-Surface Display of Semisynthetic Cyclic Peptides

Semisynthetic cyclic peptides containing both non-proteinogenic building blocks, as the synthetic part, and a genetically encoded sequence amenable to DNA-based randomization hold great potential to expand the chemical space in the quest for novel bioactive peptides. Key to an efficient selection of novel binders to biomacromolecules is a robust method to link their genotype and phenotype. A novel bacterial cell surface display technology has been developed to present cyclic peptides composed of synthetic and genetically encoded fragments in their backbones. The fragments were combined by protein trans-splicing and intramolecular oxime ligation. To this end, a split intein half and an unnatural amino acid were displayed with the genetically encoded part on the surface of Escherichia coli. Addition of the synthetic fragment equipped with the split intein partner and an aminooxy moiety, as well as the application of a pH-shift protocol, resulted in the onsurface formation of the semisynthetic cyclic peptide. This approach will serve for the generation of cyclic peptide libraries suitable for selection by fluorescence-activated cell sorting, and more generally enables chemical modification of proteins on the bacterial surface.     

A centralized energy-efficient routing protocol for wireless sensor networks

Wireless sensor networks consist of small battery powered devices with limited energy resources. Once deployed, the small sensor nodes are usually inaccessible to the user, and thus replacement of the energy source is not feasible. Hence, energy efficiency is a key design issue that needs to be enhanced in order to improve the life span of the network. Several network layer protocols have been proposed to improve the effective lifetime of a network with a limited energy supply. In this article we propose a centralized routing protocol called base-station controlled dynamic clustering protocol (BCDCP), which distributes the energy dissipation evenly among all sensor nodes to improve network lifetime and average energy savings. The performance of BCDCP is then compared to clustering-based schemes such as low-energy adaptive clustering hierarchy (LEACH), LEACH-centralized (LEACH-C), and power-efficient gathering in sensor information systems (PEGASIS). Simulation results show that BCDCP reduces overall energy consumption and improves network lifetime over its comparatives.