Rapid Identification of Malaria Vaccine Candidates Based on α-Helical Coiled Coil Protein Motif

To identify malaria antigens for vaccine development, we selected α-helical coiled coil domains of proteins predicted to be present in the parasite erythrocytic stage. The corresponding synthetic peptides are expected to mimic structurally “native” epitopes. Indeed the 95 chemically synthesized peptides were all specifically recognized by human immune sera, though at various prevalence. Peptide specific antibodies were obtained both by affinity-purification from malaria immune sera and by immunization of mice. These antibodies did not show significant cross reactions, i.e., they were specific for the original peptide, reacted with native parasite proteins in infected erythrocytes and several were active in inhibiting in vitro parasite growth. Circular dichroism studies indicated that the selected peptides assumed partial or high α-helical content. Thus, we demonstrate that the bioinformatics/chemical synthesis approach described here can lead to the rapid identification of molecules which target biologically active antibodies, thus identifying suitable vaccine candidates. This strategy can be, in principle, extended to vaccine discovery in a wide range of other pathogens

Identification of low oxygen-tolerating bacteria in prostate secretions of cancer patients and discussion of possible aetiological significance

MW was in receipt of Barts and The London Charity Equipment Grant for provision of MOLDI-TOF (Grant reference number 486/1193)

Direct characterisation of fluid lipid assemblies on mercury in electric fields

Phospholipid monolayers on mercury (Hg) surfaces have received substantial and extensive scientific interest not only because of their use as a biomembrane model but also for their application as a successful toxicity-sensing element. The monolayers show characteristic and very reproducible phase transitions manifest as consecutive voltammetric peaks in response to applied transverse electric fields. Unfortunately, apart from the results of simulation studies, there is a lack of data on the lipid phase structures to help interpret these voltammetric peaks. In this paper we report on the direct measurement of the structural changes underlying the phase transitions of phospholipid layers of dioleoyl phosphatidylcholine (DOPC) at electrified Hg surfaces using atomic force microscopy force–distance techniques. These direct measurements enable a description of the following structural changes in fluid lipid assemblies on a liquid electrode within an increasing transverse electric field. At about −1.0 V (vs Ag/AgCl) a field-facilitated ingress of ions and water into the monolayer results in a phase transition to a structured 2D emulsion. This is followed by a further phase transition at more negative potentials involving the readsorption of bilayer patches. At stronger values of field the bilayer patches form semivesicles, which subsequently collapse to form a monolayer of uncertain composition at very negative potentials. The observation that a monolayer on Hg converts to a bilayer by increasing the applied potential has allowed techniques to be developed for preparing and characterizing a near-continuous DOPC bilayer on Hg in an applied potential window within −1.0 and −1.4 V (vs Ag/AgCl)