Unexpected benefits of pre-university skills training for A-level students

First-year undergraduates can find the transition from the prescriptive learning environment at school to one of self-directed learning at university, a considerable challenge. A Pre-university Skills Course (PSC) was developed to address this issue by preparing sixth formers for the university learning style. It was piloted with students in the year prior to A-level examinations at a selective state-funded school in East Anglia. The present paper examines the effect of the course on the students’ A-level tariff. Chi-squared analysis of A-level grades of students with comparable GCSE results, indicate that students who undertook the PSC performed significantly better in their A-level results than those who did not. These data demonstrate how skills training might improve A-level performance and assist in the transition to university

Molecular genetics of Pseudomonas syringae pathovar pisi:plasmid involvement in cultivar-specific incompatibility

A mutant (PF24) of the race 1 strain, 2WA, of Pseudomonas syringrre pv.pisi has been characterized in terms of its interactions with pea (Pisum satiuum) cultivars. The mutant showed a changed reaction (avirulence to virulence) with a gruup of pea cultivars, including cvs. Belinda and Puget, previously thought to contain resistance genes R1 and R3. Avirulence towards cv. Puget was restored by transfer of any one of five cosmid clones from a race 3 (strain 870A) gene library to a rifampicin-resistant derivative of PF24. These observations were in agreement with a revised race-specific resistance genotype for Belinda and similar cultivars comprising a single resistance gene, R3. An incompatible interaction was observed between strain PF24 and cvs. Vinco (postulated to harbour race-specific resistance genes R1, R2, R 3 and R5) and Hurst's Greenshaft (R4 and possibly Rl), indicating that the mutant retains at least one avirulence gene (A1 or A1 and A4). Mutant PF24 showed loss of a cryptic plasmid (pAV212) compared with its progenitor, strain 299A. A subclone (pAV233) of one of the race 3 restoration clones showed strong hybridization with similar-sized digestion fragments in race 3 plasmid DNA, confirming the A3 gene to be plasmid-borne. Strong cross-hybridization was also observed with a single 3.27 kb EcoRI fragment of plasmid DNA present in strain 2WA but absent from strain PF24. This is consistent with the corresponding A3 determinant being located on pAV212 in the race 1 strain 2WA. The novel avirulence gene corresponding to A3 in strain 870A is provisionally designated aurPpi3. A spontaneous race-change variant (strain 1759, which expressed no avirulenc

Excision from tRNA genes of a large chromosomal region, carrying avrPphB, associated with race change in the bean pathogen, Pseudomonas syringae pv. phaseolicola

Pseudomonas syringae pv. phaseolicola (Pph) race 4 strain 1302A carries avirulence gene avrPphB. Strain RJ3, a sectoral variant from a 1302A culture, exhibited an extended host range in cultivars of bean and soybean resulting from the absence of avrPphB from the RJ3 chromosome. Complementation of RJ3 with avrPphB restored the race 4 phenotype. Both strains showed similar in planta growth in susceptible bean cultivars. Analysis of RJ3 indicated loss of > 40 kb of DNA surrounding avrPphB. Collinearity of the two genomes was determined for the left and right junctions of the deleted avrPphB region; the left junction is ≃ 19 kb and the right junction > 20 kb from avrPphB in 1302A. Sequencing revealed that the region containing avrPphB was inserted into a tRNA(LYS) gene, which was re-formed at the right junction in strain 1302A. A putative lysine tRNA pseudogene (ΨtRNA(LYS)) was found at the left junction of the insertion. All tRNA genes were in identical orientation in the chromosome. Genes near the left junction exhibited predicted protein homologies with gene products associated with a virulence locus of the periodontal pathogen Actinobacillus actinomycetemcomitans. Specific oligonucleotide primers that regions of the chromosome in other strains of Pph. Deletion of a large region of the chromosome containing an avirulence gene represents a new route to race change in Pph