Screening platelet concentrates for bacterial contamination using the most sensitive method available has a sensitivity of less than 40% because of the low numbers of bacteria in the initial contamination. Effective resolution of this problem will require a pathogen-inactivation technique.

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Pseudomonas isolates from tropical environments have been underexplored and may form an untapped reservoir of interesting secondary metabolites. In this study, we compared Pseudomonas and cyclic lipopeptide (CLP) diversity in the rhizosphere of a cocoyam root rot disease (CRRD) suppressive soil in Boteva, Cameroon with those from four conducive soils in Cameroon and Nigeria. Compared with other soils, Boteva andosols were characterized by high silt, organic matter, nitrogen and calcium. Besides, the cocoyam rhizosphere at Boteva was characterized by strains belonging mainly to the P. koreensis and P. putida (sub)groups, with representations in the P. fluorescens, P. chlororaphis, P. jessenii and P. asplenii (sub)groups. In contrast, P. putida isolates were prominent in conducive soils. Regarding CLP diversity, Boteva was characterized by strains producing 11 different CLP types with cocoyamide A producers, belonging to the P. koreensis group, being the most abundant. However, putisolvin III-V producers were the most dominant in the rhizosphere of conducive soils in both Cameroon and Nigeria. Furthermore, we elucidated the chemical structure of putisolvin derivatives-putisolvin III-V, and described its biosynthetic gene cluster. We show that high Pseudomonas and metabolic diversity may be driven by microbial competition, which likely contributes to soil suppressiveness to CRRD.

Pseudomonas cyclic lipopeptides (CLPs) are encoded non-ribosomally by biosynthetic gene clusters (BGCs) and possess diverse biological activities. In this study, we conducted chemical structure and BGC analyses with antimicrobial activity assays for two CLPs produced by Pseudomonas strains isolated from the cocoyam rhizosphere in Cameroon and Nigeria. LC-MS and NMR analyses showed that the Pseudomonas sp. COR52 and A2W4.9 produce pseudodesmin and viscosinamide, respectively. These CLPs belong to the Viscosin group characterized by a nonapeptidic moiety with a 7-membered macrocycle. Similar to other Viscosin-group CLPs, the initiatory non-ribosomal peptide synthetase (NRPS) gene of the viscosinamide BGC is situated remotely from the other two NRPS genes. In contrast, the pseudodesmin genes are all clustered in a single genomic locus. Nano- to micromolar levels of pseudodesmin and viscosinamide led to the hyphal distortion and/or disintegration of Rhizoctonia solani AG2-2 and Pythium myriotylum CMR1, whereas similar levels of White Line-Inducing Principle (WLIP), another member of the Viscosin group, resulted in complete lysis of both soil-borne phytopathogens. In addition to the identification of the biosynthetic genes of these two CLPs and the demonstration of their interaction with soil-borne pathogens, this study provides further insights regarding evolutionary divergence within the Viscosin group.

To date all of the existing monoclonal antibodies which react with human prion protein have been produced following immunisation with recombinant PrP, PrP from other species or synthetic peptide fragments. The aim of this project was to produce monoclonal antibodies raised against the native form of PrP c purified from human platelets. Following immunization of PrP -/-Edinburgh mice and the use of conventional hybridoma techniques a panel of 12 monoclonal antibodies has been established. These antibodies have been characterized by epitope mapping; binding to both native/denatured platelet PrP and native/denatured a-helical/b-sheet recombinant mouse PrP; immunoprecipitation of PrP c , PrP sc and PrP res from neurological control/vCJD brain homogenates and as probes for Western blotting, immunohistochemistry and flow-cytometry studies. A range of epitopes was recognised by the panel, with discrimination between normal a-helical and abnormal b-sheet forms. Several of the antibodies specifically captured abnormal forms of prion protein (PrP sc and PrP res ) found in vCJD-infected CNS and lymphoreticular tissues. It is hoped that these antibodies will aid in the early diagnosis and classification of human prion disease and the detection of vCJD infectivity in tissues for transplant and blood donations.There are presently 161 reported cases of vCJD in the UK, with three cases associated with the receipt of blood components. However, there is currently no routine large-scale screening test for vCJD in humans. The NHSBT considers that it is essential to be in a position to validate emerging tests for vCJD as quickly as possible, to ensure that suitable tests can be implemented in a timely manner, if required by the DoH. NHSBT is proactively preparing a panel of samples that will be used in assessing tests, to determine if they are operationally fit for purpose. This work is being undertaken in a specifically designed Test Assessment Facility (TAF) at Manchester Blood Centre, which went live in November 2005. To manage the panel, the Thermo Nautilus Laboratory Information Management System (LIMS) has been installed. Nautilus is a highly configurable LIMS, capable of handling large amounts of data. Irreversible anonymisation, integration with robotic equipment, and the ability to interrogate other data systems and retrieve information, are key features. Whole blood donations are received into the TAF and are logged into the LIMS, which retrieves basic donor demographic information, then irreversibly anonymises it. Red cell, buffy coat and plasma components are then prepared, and robot sample handlers sub-aliquot them. The LIMS then references a data output file, and processes the sub-aliquot information, creating a detailed inventory. Wireless technology is used for plate storage. The LIMS underwent extensive validation, including the use of designated test scripts to challenge and validate all aspects of the system, plus verification of compliance with GMP and GAMP regulations. The panel builds at a rate of around 125 don...