A survey of the hybridisation status of Cervus deer species on the island of Ireland

Red deer (Cervus elaphus) did not recolonise Ireland after the last glaciation, but the population in Co. Kerry is descended from an ancient (c. 5000 BP) introduction and merits conservation. During the mid-19th century exotic species including North American wapiti (C. canadensis) and Japanese sika deer (C. nippon nippon) were introduced to Ireland, mainly via Powerscourt Park, Co. Wicklow. While wapiti failed to establish, sika thrived, dispersed within Co. Wicklow and were translocated to other sites throughout Ireland. Red deer and sika are known to have hybridised in Ireland, particularly in Co. Wicklow, but an extensive survey with a large, highly diagnostic marker panel is required to assess the threat hybridisation potentially poses to the Co. Kerry red deer population. Here, 374 individuals were genotyped at a panel of 22 microsatellites and at a single mtDNA marker that are highly diagnostic for red deer and Japanese sika. The microsatellites are also moderately diagnostic for red deer and wapiti. Wapiti introgression was very low [trace evidence in 2 (0.53 %) individuals]. Despite long-standing sympatry of red deer and sika in the area, no red deer-sika hybrids were detected in Co. Kerry suggesting strong assortative mating by both species in this area. However, 80/197 (41 %) of deer sampled in Co. Wicklow and 7/15 (47 %) of deer sampled in Co. Cork were red-sika hybrids. Given their proximity and that hybrids are less likely to mate assortatively than pure individuals, the Co. Cork hybrids pose a threat to the Co. Kerry red deer.     

A Distinct Class of Genome Rearrangements Driven by Heterologous Recombination

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A novel Pseudomonas putida strain with high levels of hydantoin-converting activity, producing -amino acids

Optically pure chiral amino acids and their derivatives can be efficiently synthesised by the biocatalytic conversion of 5-substituted hydantoins in reactions catalysed by stereo-selective microbial enzymes: initially a hydantoinase catalyses the cleavage of the hydantoin producing an N-carbamyl amino acid. In certain bacteria where an N-carbamyl amino acid amidohydrolase (NCAAH) is present, the N-carbamyl amino acid intermediate is further converted to amino acid, ammonia and CO₂. In this study we report on a novel Pseudomonas putida strain which exhibits high levels of hydantoin-converting activity, yielding -amino acid products including alanine, valine, and norleucine, with bioconversion yields between 60% and 100%. The preferred substrates are generally aliphatic, but not necessarily short chain, 5-alkylhydantoins. In characterizing the enzymes from this microorganism, we have found that the NCAAH has -selectivity, while the hydantoinase is non-stereoselective. In addition, resting cell reactions under varying conditions showed that the hydantoinase is highly active, and is not subject to substrate inhibition, or product inhibition by ammonia. The rate-limiting reaction appears to be the NCAAH-catalysed conversion of the intermediate. Metal-dependence studies suggest that the hydantoinase is dependent on the presence of magnesium and cobalt ions, and is strongly inhibited by the presence of copper ions. The relative paucity of -selective hydantoin-hydrolysing enzyme systems, together with the high level of hydantoinase activity and the unusual substrate selectivity of this P. putida isolate, suggest that is has significant potential in industrial applications.     

Molecular classification of scrapie strains in mice using gene expression profiling

Transmissible spongiform encephalopathy strains demonstrate specific prion characteristics, each with specific incubation times, and strain-specific patterns of deposition of the misfolded isoform of prion, PrPSc, in the brains of infected individuals. Different biochemical properties, including glycosylation profiles and the degree of proteinase resistance, have been shown to be strain-specific. However, no relationship between these properties and the phenotypic differences in the subsequent diseases has as yet been determined. Here we explore the utility of gene expression profiles to identify differences in the host response to different strains of prion agent. We identify 114 genes that exhibit significantly different levels of expression in mice infected with three strains of scrapie. These genes represent a pool of genes involved in a strain-specific response to prion disease. We have identified the most discriminatory genes from this list utilizing a wrapper-based feature selection algorithm with external cross-validation.