177 research outputs found

    Molecular Evidence of Tomato Yellow Leaf Curl Virus-Sicily Spreading on Tomato, Pepper and Bean in Tunisia

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    Unusual symptoms including yellowing, stunting, curling, crumpling and plant size reduction were observed in tomato fields and green houses in Tunisia. These symptoms, generally associated with the Tomato yellow leaf curl virus (TYLCV) complex, have become increasingly common in recent years. In order to ascertain the molecular characteristics of Tunisian isolates by PCR, both the coat protein gene and the intergenic region of eleven isolates were amplified using specific primers, and sequenced. The PCR procedure also allowed the amplification of viral DNA fragments using a bean total DNA as a template. Phylogenetic analysis suggested that these Tunisian isolates clustered with a Sicilian isolate of TYLCSV-Sic. This is the first report of the involvement of this viral species in Phaseolus vulgaris disease

    Molecular characterization of a Moroccan isolate of Tomato yellow leaf curl Sardinia virus and differentiation of the Tomato yellow leaf curl virus complex by the polymerase chain reaction

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    The polymerase chain reaction (PCR) was used to identify an isolate of Tomato yellow leaf curl Sardinia virus (TYLCSV) from southwestern Morocco and to detect the members of the Tomato yellow leaf curl virus (TYLCV) complex. Thirty-five tomato samples with typical TYLCV symptoms were collected from infected tomato fields in the Souss-Massa region. PCR was performed with a general primer pair based on the coat protein (Cp) gene of the TYLCV complex, as well as with specific primer pairs for TYLCV and TYLCSV. Of the 35 samples tested, 29 generated a viral DNA product with the general primer pair, 29 samples gave a viral DNA product with the TYLCV-specific primers, and of these, 9 also gave a product with the TYLCSV primer pair; 6 samples did not give any PCR product with either primer pair. The full-length genome of TYLCSV was amplified with overlapping primers at the unique NcoI site in the TYLCSV genome (GenBank accession number X61153). The full-length genome of the TYLCSV isolate from Morocco is 2,777 nucleotides long (accession number AY702650) and is almost identical (97% nucleotide identity) to a TYLCSV isolate from Murcia, Spain (accession number Z25751). A PCR-based diagnostic method was developed to distinguish between TYLCV and TYLCSV in Morocco. To diagnose the TYLCV/TYLCSV complex a general primer pair was designed that anneals to a conserved region of the Cp gene. To diagnose TYLCSV exclusively, two primer pairs were designed to anneal specifically to the replication-associated protein gene (Rep) of TYLCSV from Morocco. To detect TYLCV exclusively, a primer pair previously described to amplify the intergenic region (IR) of TYLCV was used. The PCR primers were tested for their effectiveness using DNA clones of the TYLCSV from Morocco and of the TYLCV from the Dominican Republic. PCR using these primers offers a rapid means to detect the TYLCV complex and to distinguish between the two TYLCV species present in Morocco

    Saturn's icy satellites and rings investigated by Cassini - VIMS. III. Radial compositional variability

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    In the last few years Cassini-VIMS, the Visible and Infared Mapping Spectrometer, returned to us a comprehensive view of the Saturn's icy satellites and rings. After having analyzed the satellites' spectral properties (Filacchione et al. (2007a)) and their distribution across the satellites' hemispheres (Filacchione et al. (2010)), we proceed in this paper to investigate the radial variability of icy satellites (principal and minor) and main rings average spectral properties. This analysis is done by using 2,264 disk-integrated observations of the satellites and a 12x700 pixels-wide rings radial mosaic acquired with a spatial resolution of about 125 km/pixel. The comparative analysis of these data allows us to retrieve the amount of both water ice and red contaminant materials distributed across Saturn's system and the typical surface regolith grain sizes. These measurements highlight very striking differences in the population here analyzed, which vary from the almost uncontaminated and water ice-rich surfaces of Enceladus and Calypso to the metal/organic-rich and red surfaces of Iapetus' leading hemisphere and Phoebe. Rings spectra appear more red than the icy satellites in the visible range but show more intense 1.5-2.0 micron band depths. The correlations among spectral slopes, band depths, visual albedo and phase permit us to cluster the saturnian population in different spectral classes which are detected not only among the principal satellites and rings but among co-orbital minor moons as well. Finally, we have applied Hapke's theory to retrieve the best spectral fits to Saturn's inner regular satellites using the same methodology applied previously for Rhea data discussed in Ciarniello et al. (2011).Comment: 44 pages, 27 figures, 7 tables. Submitted to Icaru

    Relativistic predictions of exclusive 208Pb(p⃗,2p)207Tℓ^{208}Pb(\vec{p},2p) ^{207}T\ell analyzing powers at an incident energy of 202 MeV

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    Within the framework of the relativistic distorted wave impulse approximation (DWIA), we investigate the sensitivity of the analyzing power - for exclusive proton knockout from the 3s1/2_{1/2}, 2d3/2_{3/2} and 2d5/2_{5/2} states in 208^{208}Pb, at an incident laboratory kinetic energy of 202 MeV, and for coincident coplanar scattering angles (28.0∘28.0^{\circ}, −54.6∘-54.6^{\circ}) - to different distorting optical potentials, finite-range (FR) versus zero-range (ZR) approximations to the DWIA, as well as medium-modified coupling constants and meson masses. Results are also compared to the nonrelativistic DWIA predictions based on the Schr\"{o}dinger equation. Whereas the nonrelativistic model fails severely, both ZR and FR relativistic DWIA models provide an excellent description of the data. For the FR predictions, it is necessary to invoke a 20% reduction of sigma-nucleon and omega-nucleon coupling constants as well as for σ\sigma-, ρ\rho- and ω\omega-meson masses, by the nuclear medium. On the other hand, the ZR predictions suggest that the strong interaction in the nuclear medium is adequately represented by the free nucleon-nucleon interaction associated with the impulse approximation. We also demonstrate that, although the analyzing power is relatively insensitive to the use different relativistic global optical potential parameter sets, the prominent oscillatory behavior of this observable is largely attributed to distortion of the scattering wave functions relative to their plane wave values.Comment: 16 pages, 3 figures, submitted to Phys. Rev.

    De novo identification of mammalian ciliary motility proteins using cryo-EM

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    Dynein-decorated doublet microtubules (DMTs) are critical components of the oscillatory molecular machine of cilia, the axoneme, and have luminal surfaces patterned periodically by microtubule inner proteins (MIPs). Here we present an atomic model of the 48-nm repeat of a mammalian DMT, derived from a cryoelectron microscopy (cryo-EM) map of the complex isolated from bovine respiratory cilia. The structure uncovers principles of doublet microtubule organization and features specific to vertebrate cilia, including previously unknown MIPs, a luminal bundle of tektin filaments, and a pentameric dynein-docking complex. We identify a mechanism for bridging 48- to 24-nm periodicity across the microtubule wall and show that loss of the proteins involved causes defective ciliary motility and laterality abnormalities in zebrafish and mice. Our structure identifies candidate genes for diagnosis of ciliopathies and provides a framework to understand their functions in driving ciliary motility

    Global extent and drivers of mammal population declines in protected areas under illegal hunting pressure

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    Illegal hunting is a persistent problem in many protected areas, but an overview of the extent of this problem and its impact on wildlife is lacking. We reviewed 40 years (1980–2020) of global research to examine the spatial distribution of research and socio-ecological factors influencing population decline within protected areas under illegal hunting pressure. From 81 papers reporting 988 species/site combinations, 294 mammal species were reported to have been illegally hunted from 155 protected areas across 48 countries. Research in illegal hunting has increased substantially during the review period and showed biases towards strictly protected areas and the African continent. Population declines were most frequent in countries with a low human development index, particularly in strict protected areas and for species with a body mass over 100 kg. Our results provide evidence that illegal hunting is most likely to cause declines of large-bodied species in protected areas of resource-poor countries regardless of protected area conservation status. Given the growing pressures of illegal hunting, increased investments in people’s development and additional conservation efforts such as improving anti-poaching strategies and conservation resources in terms of improving funding and personnel directed at this problem are a growing priority

    Early carboniferous brachiopod faunas from the Baoshan block, west Yunnan, southwest China

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    38 brachiopod species in 27 genera and subgenera are described from the Yudong Formation in the Shidian-Baoshan area, west Yunnan, southwest China. New taxa include two new subgenera: Unispirifer (Septimispirifer) and Brachythyrina (Longathyrina), and seven new species: Eomarginifera yunnanensis, Marginatia cylindrica, Unispirifer (Unispirifer) xiangshanensis, Unispirifer (Septimispirifer) wafangjieensis, Brachythyrina (Brachythyrina) transversa, Brachythyrina (Longathyrina) baoshanensis, and Girtyella wafangjieensis. Based on the described material and constraints from associated coral and conodont faunas, the age of the brachiopod fauna from the Yudon Formation is considered late Tournaisian (Early Carboniferous), with a possibility extending into earlyViseacutean.<br /

    Effects of sleep deprivation on neural functioning: an integrative review

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    Sleep deprivation has a broad variety of effects on human performance and neural functioning that manifest themselves at different levels of description. On a macroscopic level, sleep deprivation mainly affects executive functions, especially in novel tasks. Macroscopic and mesoscopic effects of sleep deprivation on brain activity include reduced cortical responsiveness to incoming stimuli, reflecting reduced attention. On a microscopic level, sleep deprivation is associated with increased levels of adenosine, a neuromodulator that has a general inhibitory effect on neural activity. The inhibition of cholinergic nuclei appears particularly relevant, as the associated decrease in cortical acetylcholine seems to cause effects of sleep deprivation on macroscopic brain activity. In general, however, the relationships between the neural effects of sleep deprivation across observation scales are poorly understood and uncovering these relationships should be a primary target in future research
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