HAPPY mapping in a plant genome: reconstruction and analysis of a high-resolution physical map of a 1.9 Mbp region of Arabidopsis thaliana chromosome 4

HAPPY mapping is an in vitro approach for defining the order and spacing of DNA markers directly on native genomic DNA. This cloning-free technique is based on analysing the segregation of markers amplified from high molecular weight genomic DNA which has been broken randomly and 'segregated' by limiting dilution into subhaploid samples. It is a uniquely versatile tool, allowing for the construction of genome maps with flexible ranges and resolutions. Moreover, it is applicable to plant genomes, for which many of the techniques pioneered in animal genomes are inapplicable or inappropriate. We report here its demonstration in a plant genome by reconstructing the physical map of a 1.9 Mbp region around the FCA locus of Arabidopsis thaliana. The resulting map, spanning around 10% of chromosome 4, is in excellent agreement with the DNA sequence and has a mean marker spacing of 16 kbp. We argue that HAPPY maps of any required resolution can be made immediately and with relatively little effort for most plant species and, furthermore, that such maps can greatly aid the construction of regional or genome-wide physical maps

Real-Time PCRs and Fingerprinting assays for the Detection and Characterization of Salmonella Genomic Island-1 Encoding Multidrug Resistance: Application to 445 European Isolates of Salmonella, Escherichia coli, Shigella and Proteus

Salmonella Genomic Island-1 (SGI-1) harbors a cluster of genes encoding multidrug resistance (MDR). SGI-1 is horizontally transmissible and is therefore of significant public health concern. This study presents two novel realtime PCRs detecting three SGI-1 protein-coding genes and a SGI-1 fingerprinting assay. These assays were applied to 445 European enterobacterial isolates. Results from real-time PCRs were comparable to those obtained from gelbased PCRs used for the detection of SGI-1, but were rapid to perform and suitable for large-scale screening. Furthermore, real-time PCRs also detected SGI-1 even when only part of the island was present in bacterial isolates. No trace of SGI-1 was detected in isolates other than Salmonella enterica. The fingerprints showed that regions of SGI-1 outside the MDR region exhibited genomic variations between isolates. In conclusion, the realtime PCRs described here are suitable for the detection of SGI-1 in bacterial isolates. Further studies are necessary to elucidate divergence in its non-MDR region

Exposure to solar UVR suppresses cell-mediated immunization responses in humans: the Australian ultraviolet radiation and immunity study

Animal and human studies show that exposure to solar-simulated UVR is immunomodulatory. Human studies that used natural sun exposure and controlled for confounding are rare. We immunized 217 healthy adults (age range = 18-40 years) with a T-cell-dependent antigen, keyhole limpet hemocyanin, and measured personal clothing-adjusted UVR exposure (for 5 days before and after immunization), lifetime cumulative UVR exposure, serum 25-hydroxyvitamin D concentration at immunization, and potential confounding factors. We tested cellular and humoral immune responses in relation to UVR exposure. The delayed-type hypersensitivity response to keyhole limpet hemocyanin recall challenge was lower in individuals with higher personal clothing-adjusted UVR exposure on the day before immunization (P = 0.015) and during intervals spanning the day before to 2-3 days after immunization. There was an incremental increase in T helper type 17 cells (as a proportion of CD4+ T cells) from preimmunization to postimmunization in the high, compared with the low, personal clothing-adjusted UVR exposure group (0.31% vs. -0.39%, P = 0.004). Keyhole limpet hemocyanin-specific antibody titers were not associated with acute or cumulative UVR exposure or serum 25-hydroxyvitamin D levels. Higher UVR exposure at antigen sensitization was associated with a reduced delayed-type hypersensitivity response and altered T helper type 17 kinetics. This has implications for the effectiveness of vaccinations and susceptibility to infections that rely on cell-mediated immune responses.Ashwin Swaminathan, Simone L. Harrison, Natkunam Ketheesan, Christel H.A. van den Boogaard, Keith Dear, Martin Allen ... et al