Quantitative PCR-based genome size estimation of the astigmatid mites Sarcoptes scabiei, Psoroptes ovis and Dermatophagoides pteronyssinus

Background: The lack of genomic data available for mites limits our understanding of their biology. Evolving high-throughput sequencing technologies promise to deliver rapid advances in this area, however, estimates of genome size are initially required to ensure sufficient coverage. Methods. Quantitative real-time PCR was used to estimate the genome sizes of the burrowing ectoparasitic mite Sarcoptes scabiei, the non-burrowing ectoparasitic mite Psoroptes ovis, and the free-living house dust mite Dermatophagoides pteronyssinus. Additionally, the chromosome number of S. scabiei was determined by chromosomal spreads of embryonic cells derived from single eggs. Results: S. scabiei cells were shown to contain 17 or 18 small (< 2 M) chromosomes, suggesting an XO sex-determination mechanism. The average estimated genome sizes of S. scabiei and P. ovis were 96 ( 7) Mb and 86 ( 2) Mb respectively, among the smallest arthropod genomes reported to date. The D. pteronyssinus genome was estimated to be larger than its parasitic counterparts, at 151 Mb in female mites and 218 Mb in male mites. Conclusions: This data provides a starting point for understanding the genetic organisation and evolution of these astigmatid mites, informing future sequencing projects. A comparitive genomic approach including these three closely related mites is likely to reveal key insights on mite biology, parasitic adaptations and immune evasion

Gac two-component system in Pseudomonas syringae pv. tabaci is required for virulence but not for hypersensitive reaction

Pseudomonas syringae pv. tabaci 6605 causes wildfire disease on host tobacco plants. To investigate the regulatory mechanism of the expression of virulence, Gac two-Component system-defective mutants, Delta gacA and Delta gacS, and a double mutant, Delta gacA Delta gacS, were generated. These mutants produced smaller amounts of N-acyl homoserine lactones required for quorum sensing, had lost swarming motility, and had reduced expression of virulence-related hrp genes and the algT gene required for exopolysaccharide production. The ability of the mutants to cause disease symptoms in their host tobacco plant was remarkably reduced, while they retained the ability to induce hypersensitive reaction (HR) in the nonhost plants. These results indicated that the Gac two-component system of P. syringae pv. tabaci 6605 is indispensable for virulence on the host plant, but not for HR induction in the nonhost plants.</p

BCL10 is rarely mutated in human prostate carcinoma, small-cell lung cancer, head and neck tumours, renal carcinoma and sarcomas

We have used single-strand conformation polymorphism (SSCP) analysis to screen for mutations in the BCL 10 gene in 81 primary prostate carcinomas, 20 squamous cell cancers of the head and neck, 15 small-cell lung cancer cell lines, 24 renal carcinoma cell lines and 13 sarcoma cell lines. We failed to find evidence of somatically acquired mutations of the BCL10 gene suggesting that BCL 10 does not play a major role in the development of these malignancies

Identifying the science and technology dimensions of emerging public policy issues through horizon scanning

Public policy requires public support, which in turn implies a need to enable the public not just to understand policy but also to be engaged in its development. Where complex science and technology issues are involved in policy making, this takes time, so it is important to identify emerging issues of this type and prepare engagement plans. In our horizon scanning exercise, we used a modified Delphi technique [1]. A wide group of people with interests in the science and policy interface (drawn from policy makers, policy adviser, practitioners, the private sector and academics) elicited a long list of emergent policy issues in which science and technology would feature strongly and which would also necessitate public engagement as policies are developed. This was then refined to a short list of top priorities for policy makers. Thirty issues were identified within broad areas of business and technology; energy and environment; government, politics and education; health, healthcare, population and aging; information, communication, infrastructure and transport; and public safety and national security.Public policy requires public support, which in turn implies a need to enable the public not just to understand policy but also to be engaged in its development. Where complex science and technology issues are involved in policy making, this takes time, so it is important to identify emerging issues of this type and prepare engagement plans. In our horizon scanning exercise, we used a modified Delphi technique [1]. A wide group of people with interests in the science and policy interface (drawn from policy makers, policy adviser, practitioners, the private sector and academics) elicited a long list of emergent policy issues in which science and technology would feature strongly and which would also necessitate public engagement as policies are developed. This was then refined to a short list of top priorities for policy makers. Thirty issues were identified within broad areas of business and technology; energy and environment; government, politics and education; health, healthcare, population and aging; information, communication, infrastructure and transport; and public safety and national security

Maturation-Induced Cloaking of Neutralization Epitopes on HIV-1 Particles

To become infectious, HIV-1 particles undergo a maturation process involving proteolytic cleavage of the Gag and Gag-Pol polyproteins. Immature particles contain a highly stable spherical Gag lattice and are impaired for fusion with target cells. The fusion impairment is relieved by truncation of the gp41 cytoplasmic tail (CT), indicating that an interaction between the immature viral core and gp41 within the particle represses HIV-1 fusion by an unknown mechanism. We hypothesized that the conformation of Env on the viral surface is regulated allosterically by interactions with the HIV-1 core during particle maturation. To test this, we quantified the binding of a panel of monoclonal antibodies to mature and immature HIV-1 particles by immunofluorescence imaging. Surprisingly, immature particles exhibited markedly enhanced binding of several gp41-specific antibodies, including two that recognize the membrane proximal external region (MPER) and neutralize diverse HIV-1 strains. Several of the differences in epitope exposure on mature and immature particles were abolished by truncation of the gp41 CT, thus linking the immature HIV-1 fusion defect with altered Env conformation. Our results suggest that perturbation of fusion-dependent Env conformational changes contributes to the impaired fusion of immature particles. Masking of neutralization-sensitive epitopes during particle maturation may contribute to HIV-1 immune evasion and has practical implications for vaccine strategies targeting the gp41 MPER

Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV

We present limits on anomalous WWZ and WW-gamma couplings from a search for WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p -> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron Collider during the 1992-1995 run. The data sample corresponds to an integrated luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling parameters, the 95% CL limits on the CP-conserving couplings are -0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also presented.Comment: 11 pages, 2 figures, 2 table

Search for New Physics in e mu X Data at D0 Using Sleuth: A Quasi-Model-Independent Search Strategy for New Physics

We present a quasi-model-independent search for the physics responsible for electroweak symmetry breaking. We define final states to be studied, and construct a rule that identifies a set of relevant variables for any particular final state. A new algorithm ("Sleuth") searches for regions of excess in those variables and quantifies the significance of any detected excess. After demonstrating the sensitivity of the method, we apply it to the semi-inclusive channel e mu X collected in 108 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV at the D0 experiment during 1992-1996 at the Fermilab Tevatron. We find no evidence of new high p_T physics in this sample.Comment: 23 pages, 12 figures. Submitted to Physical Review

Common and Distinct Roles of Juvenile Hormone Signaling Genes in Metamorphosis of Holometabolous and Hemimetabolous Insects

Insect larvae metamorphose to winged and reproductive adults either directly (hemimetaboly) or through an intermediary pupal stage (holometaboly). In either case juvenile hormone (JH) prevents metamorphosis until a larva has attained an appropriate phase of development. In holometabolous insects, JH acts through its putative receptor Methoprene-tolerant (Met) to regulate Krüppel-homolog 1 (Kr-h1) and Broad-Complex (BR-C) genes. While Met and Kr-h1 prevent precocious metamorphosis in pre-final larval instars, BR-C specifies the pupal stage. How JH signaling operates in hemimetabolous insects is poorly understood. Here, we compare the function of Met, Kr-h1 and BR-C genes in the two types of insects. Using systemic RNAi in the hemimetabolous true bug, Pyrrhocoris apterus, we show that Met conveys the JH signal to prevent premature metamorphosis by maintaining high expression of Kr-h1. Knockdown of either Met or Kr-h1 (but not of BR-C) in penultimate-instar Pyrrhocoris larvae causes precocious development of adult color pattern, wings and genitalia. A natural fall of Kr-h1 expression in the last larval instar normally permits adult development, and treatment with an exogenous JH mimic methoprene at this time requires both Met and Kr-h1 to block the adult program and induce an extra larval instar. Met and Kr-h1 therefore serve as JH-dependent repressors of deleterious precocious metamorphic changes in both hemimetabolous and holometabolous juveniles, whereas BR-C has been recruited for a new role in specifying the holometabolous pupa. These results show that despite considerable evolutionary distance, insects with diverse developmental strategies employ a common-core JH signaling pathway to commit to adult morphogenesis

Search For Heavy Pointlike Dirac Monopoles

We have searched for central production of a pair of photons with high transverse energies in $p\bar p$ collisions at $\sqrt{s} = 1.8$ TeV using $70 pb^{-1}$ of data collected with the D\O detector at the Fermilab Tevatron in 1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of $610, 870, or 1580 GeV/c^2$ on the mass of a spin 0, 1/2, or 1 Dirac monopole.Comment: 12 pages, 4 figure