34 research outputs found
Identification of Host Genes Involved in Geminivirus Infection Using a Reverse Genetics Approach
Geminiviruses, like all viruses, rely on the host cell machinery to establish a successful infection, but the identity and function of these required host proteins remain largely unknown. Tomato yellow leaf curl Sardinia virus (TYLCSV), a monopartite geminivirus, is one of the causal agents of the devastating Tomato yellow leaf curl disease (TYLCD). The transgenic 2IRGFP N. benthamiana plants, used in combination with Virus Induced Gene Silencing (VIGS), entail an important potential as a tool in reverse genetics studies to identify host factors involved in TYLCSV infection. Using these transgenic plants, we have made an accurate description of the evolution of TYLCSV replication in the host in both space and time. Moreover, we have determined that TYLCSV and Tobacco rattle virus (TRV) do not dramatically influence each other when co-infected in N. benthamiana, what makes the use of TRV-induced gene silencing in combination with TYLCSV for reverse genetic studies feasible. Finally, we have tested the effect of silencing candidate host genes on TYLCSV infection, identifying eighteen genes potentially involved in this process, fifteen of which had never been implicated in geminiviral infections before. Seven of the analyzed genes have a potential anti-viral effect, whereas the expression of the other eleven is required for a full infection. Interestingly, almost half of the genes altering TYLCSV infection play a role in postranslational modifications. Therefore, our results provide new insights into the molecular mechanisms underlying geminivirus infections, and at the same time reveal the 2IRGFP/VIGS system as a powerful tool for functional reverse genetics studies
Simultaneous measurement of muon neutrino quasielastic-like cross sections on CH, C, water, Fe, and Pb as a function of muon kinematics at MINERvA
This paper presents the first simultaneous measurement of the
quasielastic-like neutrino-nucleus cross sections on C, water, Fe, Pb and
scintillator (hydrocarbon or CH) as a function of longitudinal and transverse
muon momentum. The ratio of cross sections per nucleon between Pb and CH is
always above unity and has a characteristic shape as a function of transverse
muon momentum that evolves slowly as a function of longitudinal muon momentum.
The ratio is constant versus longitudinal momentum within uncertainties above a
longitudinal momentum of 4.5GeV/c. The cross section ratios to CH for C, water,
and Fe remain roughly constant with increasing longitudinal momentum, and the
ratios between water or C to CH do not have any significant deviation from
unity. Both the overall cross section level and the shape for Pb and Fe as a
function of transverse muon momentum are not reproduced by current neutrino
event generators. These measurements provide a direct test of nuclear effects
in quasielastic-like interactions, which are major contributors to
long-baseline neutrino oscillation data samples.Comment: 9 pages, 8 flgures, including supplemental materia
Neutrino-induced coherent production in C, CH, Fe and Pb at GeV
MINERvA has measured the -induced coherent cross section
simultaneously in hydrocarbon (CH), graphite (C), iron (Fe) and lead (Pb)
targets using neutrinos from 2 to 20 GeV. The measurements exceed the
predictions of the Rein-Sehgal and Berger-Sehgal PCAC based models at multi-GeV
energies and at produced energies and angles,
GeV and . Measurements of the cross-section ratios of
Fe and Pb relative to CH reveal the effective -scaling to increase from an
approximate scaling at few GeV to an scaling for
GeV
Simultaneous measurement of muon neutrino charged-current single production in CH, C, HO, Fe, and Pb targets in MINERvA
Neutrino-induced charged-current single production in the
resonance region is of considerable interest to
accelerator-based neutrino oscillation experiments. In this work, high
statistics differential cross sections are reported for the semi-exclusive
reaction nucleon(s) on scintillator, carbon,
water, iron, and lead targets recorded by MINERvA using a wide-band
beam with \left \approx 6~GeV. Suppression of the cross
section at low and enhancement of low are observed in both light
and heavy nuclear targets compared to phenomenological models used in current
neutrino interaction generators. The cross-section ratios for iron and lead
compared to CH across the kinematic variables probed are 0.8 and 0.5
respectively, a scaling which is also not predicted by current generators.Comment: 6 pages, 6 figures, 117 pages of supplementary material; submitted to
Physical Review Letter
Improved constraint on the MINERνA medium energy neutrino flux using ν¯e−→ν¯e− data
Processes with precisely known cross sections, like neutrino-electron elastic scattering (νe−→νe−) and inverse muon decay (νμe−→μ−νe) have been used by MINERνA to constrain the uncertainty on the neutrinos at the main injector (NuMI) neutrino beam flux. This work presents a new measurement of neutrino elastic scattering with electrons using the medium energy ¯νμ-enhanced NuMI beam. A sample of 578 events after background subtraction is used in combination with the previous measurement on the νμ beam and the inverse muon decay measurement to reduce the uncertainty on the νμ flux in the νμ-enhanced beam from 7.6% to 3.3% and the ¯νμ flux in the ¯νμ-enhanced beam from 7.8% to 4.7%