Probing the HIV-1 Genomic RNA Trafficking Pathway and Dimerization by Genetic Recombination and Single Virion Analyses

Once transcribed, the nascent full-length RNA of HIV-1 must travel to the appropriate host cell sites to be translated or to find a partner RNA for copackaging to form newly generated viruses. In this report, we sought to delineate the location where HIV-1 RNA initiates dimerization and the influence of the RNA transport pathway used by the virus on downstream events essential to viral replication. Using a cell-fusion-dependent recombination assay, we demonstrate that the two RNAs destined for copackaging into the same virion select each other mostly within the cytoplasm. Moreover, by manipulating the RNA export element in the viral genome, we show that the export pathway taken is important for the ability of RNA molecules derived from two viruses to interact and be copackaged. These results further illustrate that at the point of dimerization the two main cellular export pathways are partially distinct. Lastly, by providing Gag in trans, we have demonstrated that Gag is able to package RNA from either export pathway, irrespective of the transport pathway used by the gag mRNA. These findings provide unique insights into the process of RNA export in general, and more specifically, of HIV-1 genomic RNA trafficking

Spreading Patterns of the Influenza A (H1N1) Pandemic

We investigate the dynamics of the 2009 influenza A (H1N1/S-OIV) pandemic by analyzing data obtained from World Health Organization containing the total number of laboratory-confirmed cases of infections - by country - in a period of 69 days, from 26 April to 3 July, 2009. Specifically, we find evidence of exponential growth in the total number of confirmed cases and linear growth in the number of countries with confirmed cases. We also find that, i) at early stages, the cumulative distribution of cases among countries exhibits linear behavior on log-log scale, being well approximated by a power law decay; ii) for larger times, the cumulative distribution presents a systematic curvature on log-log scale, indicating a gradual change to lognormal behavior. Finally, we compare these empirical findings with the predictions of a simple stochastic model. Our results could help to select more realistic models of the dynamics of influenza-type pandemics

Are recovery stories helpful for women with eating disorders? A pilot study and commentary on future research

Background: Anecdotally it is well known that eating disorder memoirs are popular with people with anorexia nervosa and recovery stories are readily available online. However, no research to date has empirically explored whether such stories are helpful for current sufferers. The aim of the current pilot study was to explore the efficacy of recovery narratives as a means of improving motivation and self-efficacy and to qualitatively explore patient perspectives of such stories. Method: Fifty-seven women with anorexia nervosa and subclinical anorexia nervosa participated in this online study. Participants were randomised to either receive recovery stories or to a wait-list control group. After completing baseline measures, participants read five stories about recovery, and completed post-intervention measures two weeks later. Results: The quantitative results indicated that reading stories of recovery had no effect on motivation and self-efficacy over a two-week period. In contrast, the qualitative results showed that the stories generated thoughts about the possibility of recovery and the majority indicated they would recommend them to others. Conclusions: This study adds to a growing body of research exploring the integration of voices of lived experience into treatment approaches. Future research should focus on 1) identifying for whom and at which stage of illness recovery stories might be helpful; 2) the mechanism via which they might operate; and 3) the most helpful way of presenting such stories

Cluster Lenses

Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining to cluster formation and evolution, as well as constraining the nature of dark matter; (ii) the study of the lensed objects - probing the properties of the background lensed galaxy population - which is statistically at higher redshifts and of lower intrinsic luminosity thus enabling the probing of galaxy formation at the earliest times right up to the Dark Ages; and (iii) the study of the geometry of the Universe - as the strength of lensing depends on the ratios of angular diameter distances between the lens, source and observer, lens deflections are sensitive to the value of cosmological parameters and offer a powerful geometric tool to probe Dark Energy. In this review, we present the basics of cluster lensing and provide a current status report of the field.Comment: About 120 pages - Published in Open Access at: http://www.springerlink.com/content/j183018170485723/ . arXiv admin note: text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author

High-Resolution X-Ray Structure of the Trimeric Scar/WAVE-Complex Precursor Brk1

The Scar/WAVE-complex links upstream Rho-GTPase signaling to the activation of the conserved Arp2/3-complex. Scar/WAVE-induced and Arp2/3-complex-mediated actin nucleation is crucial for actin assembly in protruding lamellipodia to drive cell migration. The heteropentameric Scar/WAVE-complex is composed of Scar/WAVE, Abi, Nap, Pir and a small polypeptide Brk1/HSPC300, and recent work suggested that free Brk1 serves as a homooligomeric precursor in the assembly of this complex. Here we characterized the Brk1 trimer from Dictyostelium by analytical ultracentrifugation and gelfiltration. We show for the first time its dissociation at concentrations in the nanomolar range as well as an exchange of subunits within different DdBrk1 containing complexes. Moreover, we determined the three-dimensional structure of DdBrk1 at 1.5 Å resolution by X-ray crystallography. Three chains of DdBrk1 are associated with each other forming a parallel triple coiled-coil bundle. Notably, this structure is highly similar to the heterotrimeric α-helical bundle of HSPC300/WAVE1/Abi2 within the human Scar/WAVE-complex. This finding, together with the fact that Brk1 is collectively sandwiched by the remaining subunits and also constitutes the main subunit connecting the triple-coil domain of the HSPC300/WAVE1/Abi2/ heterotrimer to Sra1(Pir1), implies a critical function of this subunit in the assembly process of the entire Scar/WAVE-complex

Face Coding Is Bilateral in the Female Brain

Background: It is currently believed that face processing predominantly activates the right hemisphere in humans, but available literature is very inconsistent. Methodology/Principal Findings: In this study, ERPs were recorded in 50 right-handed women and men in response to 390 faces (of different age and sex), and 130 technological objects. Results showed no sex difference in the amplitude of N170 to objects; a much larger face-specific response over the right hemisphere in men, and a bilateral response in women; a lack of face-age coding effect over the left hemisphere in men, with no differences in N170 to faces as a function of age; a significant bilateral face-age coding effect in women. Conclusions/Significance: LORETA reconstruction showed a significant left and right asymmetry in the activation of the fusiform gyrus (BA19), in women and men, respectively. The present data reveal a lesser degree of lateralization of brain functions related to face coding in women than men. In this light, they may provide an explanation of the inconsistencies in the available literature concerning the asymmetric activity of left and right occipito-temporal cortices devoted to fac

Factors influencing citrus fruit scarring caused by Pezothrips kellyanus

[EN] Kelly s citrus thrips (KCT) Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) is a recently recorded cosmopolitan citrus pest, causing fruit scarring that results in downgrading of fruit. Due to the detrimental effects caused on fruits by KCT, we wanted to study some of the factors influencing fruit scarring. Specifically, the objectives were: (1) to determine the fruit development stage when citrus fruits are damaged by KCT and the population structure of KCT during this period, (2) to study the influence of temperature on intensity of damage, and finally, (3) to identify alternative host plants. KCT populations on flowers and fruitlets and alternate plant hosts were sampled in four citrus orchards from 2008 to 2010. The percentage of damaged fruits was also recorded. The exotic vine Araujia sericifera (Apocynaceae) was recorded as a new host for KCT. Thrips scarring started to increase at 350 650 degree-days (DD) above 10.2 C, coinciding with a peak abundance of the second instar larval stages over all 3 years of the study. The maximum percentage of larval stages of KCT was observed in the 3 years at about 500 DD, a period which corresponds to the end of May or early June. Variation in the severity of fruit scarring appeared to be related to air temperature. Temperature likely affects the synchronisation between the peak in abundance of KCT larvae, and the period when fruitlets are susceptible to thrips damage. Temperature can also influence the survival and development of KCT populations in citrus and other host plants in the citrus agro-ecosystem.The authors thank Alejandro Tena for his valuable suggestions and two anonymous referees for their careful review and helpful comments. We also extend our thanks to the owners of the commercial orchards for giving us permission to use their citrus orchards. The first author was awarded an FPI fellowship from the Polytechnic University of Valencia to obtain her PhD degree.Navarro Campos, C.; Pekas, A.; Aguilar Martí, MA.; Garcia Marí, F. (2013). Factors influencing citrus fruit scarring caused by Pezothrips kellyanus. Journal of Pest Science. (86):459-467. doi:10.1007/s10340-013-0489-7S45946786Baker GJ (2006) Kelly citrus thrips management. Fact sheet. Government of South Australia, primary industries and resources SA. http://www.sardi.sa.gov.au/__data/assets/pdf_file/0010/44875/kctfact_sheet.pdf . Accessed 16 July 2012Baker GJ, Jackman DJ, Keller M, MacGregor A, Purvis S (2002) Development of an integrated pest management system for thrips in Citrus. HAL Final Report CT97007. http://www.sardi.sa.gov.au/pestsdiseases/horticulture/horticultural_pests/kelly_citrus_thrips/research_report_1997-2000 . Accessed 16 July 2012Bedford ECG (1998) Thrips, wind and other blemishes. Citrus pests in the Republic of South Africa. 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Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

Small mammal responses to Amazonian forest islands are modulated by their forest dependence

Hydroelectric dams have induced widespread loss, fragmentation and degradation of terrestrial habitats in lowland tropical forests. Yet their ecological impacts have been widely neglected, particularly in developing countries, which are currently earmarked for exponential hydropower development. Here we assess small mammal assemblage responses to Amazonian forest habitat insularization induced by the 28-year-old Balbina Hydroelectric Dam. We sampled small mammals on 25 forest islands (0.83–1466 ha) and four continuous forest sites in the mainland to assess the overall community structure and species-specific responses to forest insularization. We classified all species according to their degree of forest-dependency using a multi-scale approach, considering landscape, patch and local habitat characteristics. Based on 65,520 trap-nights, we recorded 884 individuals of at least 22 small mammal species. Species richness was best predicted by island area and isolation, with small islands ( 200 ha; 10.8 ± 1.3 species) and continuous forest sites (∞ ha; 12.5 ± 2.5 species) exhibited similarly high species richness. Forest-dependent species showed higher local extinction rates and were often either absent or persisted at low abundances on small islands, where non-forest-dependent species became hyper-abundant. Species capacity to use non-forest habitat matrices appears to dictate small mammal success in small isolated islands. We suggest that ecosystem functioning may be highly disrupted on small islands, which account for 62.7% of all 3546 islands in the Balbina Reservoir