66 research outputs found
ASSESSMENT OF THE RESISTANCE CONFERRED BY THE \u3ci\u3ebc-1\u3c/i\u3e ALLELES TO \u3ci\u3eBean common mosaic necrosis virus\u3c/i\u3e
INTRODUCTION: Bean common mosaic necrosis virus (BCMNV) is a potyvirus comprising several strains classified into two pathogroups according to the interactions with six recessive resistance alleles in common bean (1). These pathogroups (PGs), numbered III and VI, are defined by the ability (PG-VI) or inability (PG-III) of a BCMNV isolate to replicate in bean differential lines carrying bc-1 or bc-12 resistance alleles. The biological and molecular basis for this differential response of BCMNV isolates to the presence of bc-1 alleles is not known. Conversely, the genetic determinants involved in interactions of BCMNV strains with bc-1 resistance alleles have not yet been identified either. We performed a complete biological and molecular study of three isolates of BCMNV belonging to PG-III and VI, collected in California and in Oregon. Particular attention was paid to BCMNV isolates’ performance in common bean lines from host groups 2, 3, and 9, harboring bc-1 and bc-12 alleles. The data obtained suggest that the bc-1 alleles restricted systemic movement of PG-III isolates of BCMNV, while cell-tocell movement of the virus in inoculated leaves did not seem to be affected
ASSESSMENT OF THE RESISTANCE CONFERRED BY THE \u3ci\u3ebc-1\u3c/i\u3e ALLELES TO \u3ci\u3eBean common mosaic necrosis virus\u3c/i\u3e
INTRODUCTION: Bean common mosaic necrosis virus (BCMNV) is a potyvirus comprising several strains classified into two pathogroups according to the interactions with six recessive resistance alleles in common bean (1). These pathogroups (PGs), numbered III and VI, are defined by the ability (PG-VI) or inability (PG-III) of a BCMNV isolate to replicate in bean differential lines carrying bc-1 or bc-12 resistance alleles. The biological and molecular basis for this differential response of BCMNV isolates to the presence of bc-1 alleles is not known. Conversely, the genetic determinants involved in interactions of BCMNV strains with bc-1 resistance alleles have not yet been identified either. We performed a complete biological and molecular study of three isolates of BCMNV belonging to PG-III and VI, collected in California and in Oregon. Particular attention was paid to BCMNV isolates’ performance in common bean lines from host groups 2, 3, and 9, harboring bc-1 and bc-12 alleles. The data obtained suggest that the bc-1 alleles restricted systemic movement of PG-III isolates of BCMNV, while cell-tocell movement of the virus in inoculated leaves did not seem to be affected
Formal symplectic groupoid of a deformation quantization
We give a self-contained algebraic description of a formal symplectic
groupoid over a Poisson manifold M. To each natural star product on M we then
associate a canonical formal symplectic groupoid over M. Finally, we construct
a unique formal symplectic groupoid `with separation of variables' over an
arbitrary Kaehler-Poisson manifold.Comment: 41 page, Lemma 13, several typos and notations correcte
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Bean common mosaic virus Isolate Exhibits a Novel Pathogenicity Profile in Common Bean, Overcoming the bc-3 Resistance Allele Coding for the Mutated eIF4E Translation Initiation Factor
Resistance against Bean common mosaic virus (BCMV) in Phaseolus vulgaris is governed by six recessive resistance alleles at four loci. One of these alleles, bc-3, is able to protect P. vulgaris against all BCMV strains and against other potyviruses; bc-3 was identified as the eIF4E allele carrying mutated eukaryotic translation initiation factor gene. Here, we characterized a novel BCMV isolate 1755a that was able to overcome bc-2 and bc-3 alleles in common bean. Thus, it displayed a novel pattern of interactions with resistance genes in P. vulgaris, and was assigned to a new pathogroup, PG-VIII. The IVT7214 cultivar supporting the replication of BCMV-1755a was found to have the intact homozygous bc-3 cleaved amplified polymorphic sequences marker and corresponding mutations in the eIF4E allele that confer resistance to BCMV isolates from all other pathogroups as well as to other potyviruses. The VPg protein of 1755a had seven amino acid substitutions relative to VPgs of other BCMV isolates unable to overcome bc-3. The 1755a genome was found to be a recombinant between NL1, US1 (both PG-I), and a yet unknown BCMV strain. Analysis of the recombination patterns in the genomes of NL1 and US1 (PG-I), NY15P (PG-V), US10 and RU1-OR (PG-VII), and 1755a (PG-VIII), indicated that P1/HC-Pro cistrons of BCMV strains may interact with most resistance genes. This is the first report of a BCMV isolate able to overcome the bc-3 resistance allele, suggesting that the virus has evolved mechanisms to overcome multiple resistance genes available in common bean
Infinitesimal deformations of a formal symplectic groupoid
Given a formal symplectic groupoid over a Poisson manifold ,
we define a new object, an infinitesimal deformation of , which can be
thought of as a formal symplectic groupoid over the manifold equipped with
an infinitesimal deformation of the Poisson bivector
field . The source and target mappings of a deformation of are
deformations of the source and target mappings of . To any pair of natural
star products having the same formal symplectic groupoid
we relate an infinitesimal deformation of . We call it the deformation
groupoid of the pair . We give explicit formulas for the
source and target mappings of the deformation groupoid of a pair of star
products with separation of variables on a Kaehler- Poisson manifold. Finally,
we give an algorithm for calculating the principal symbols of the components of
the logarithm of a formal Berezin transform of a star product with separation
of variables. This algorithm is based upon some deformation groupoid.Comment: 22 pages, the paper is reworked, new proofs are adde
Properties of the transient X-ray pulsar Swift J1816.7--1613 and its optical companion
We present results of investigation of the poorly studied X-ray pulsar Swift
J1816.7--1613 during its transition from the type I outburst to the quiescent
state. Our studies are based on the data obtained from X-ray observatories
\textit{Swift}, \textit{NuSTAR} and \textit{Chandra} alongside with the latest
IR data from UKIDSS/GPS and \textit{Spitzer}/GLIMPSE surveys. The aim of the
work is to determine parameters of the system: the strength of the neutron star
magnetic field and the distance to the source, which are required for the
interpretation of the source behaviour in the framework of physically motivated
models. No cyclotron absorption line was detected in the broad-band energy
spectrum. However, the timing analysis hints at the typical for the X-ray
pulsars magnetic field from a few to a few G.
We also estimated type of the IR-companion as a B0-2e star located at distance
of 7--13~kpc.Comment: 8 pages, 7 figures, accepted for publication in A&
X-ray pulsar XTE J1858+034: discovery of the cyclotron line and the revised optical identification
We present results of a detailed investigation of the poorly studied X-ray
pulsar XTE J1858+034 based on the data obtained with the NuSTAR observatory
during the outburst of the source in 2019. The spectral analysis resulted in
the discovery of a cyclotron absorption feature in the source spectrum at ~48
keV both in the pulse phase averaged and resolved spectra. Accurate X-ray
localization of the source using the NuSTAR and Chandra observatories allowed
us to accurately determine the position of the X-ray source and identify the
optical companion of the pulsar. The analysis of the counterpart properties
suggested that the system is likely a symbiotic binary hosting an X-ray pulsar
and a late type companion star of K-M classes rather than Be X-ray binary as
previously suggested.Comment: 12 pages, 12 figures, accepted by Ap
Folding of poly-amino acids and intrinsically disordered proteins in overcrowded milieu induced by pH change
pH-induced structural changes of the synthetic homopolypeptides poly-E, poly-K, poly-R, and intrinsically disordered proteins (IDPs) prothymosin alpha (ProT alpha) and linker histone H1, in concentrated PEG solutions simulating macromolecular crowding conditions within the membrane-less organelles, were characterized. The conformational transitions of the studied poly-amino acids in the concentrated PEG solutions depend on the polymerization degree of these homopolypeptides, the size of their side chains, the charge distribution of the side chains, and the crowding agent concentration. The results obtained for poly-amino acids are valid for IDPs having a significant total charge. The overcrowded conditions promote a significant increase in the cooperativity of the pH-induced coil-alpha-helix transition of ProTa and provoke histone H1 aggregation. The most favorable conditions for the pH-induced structural transitions in concentrated PEG solutions are realized when the charged residues are grouped in blocks, and when the distance between the end of the side group carrying charge and the backbone is small. Therefore, the block-wise distribution of charged residues within the IDPs not only plays an important role in the liquid-liquid phase transitions, but may also define the expressivity of structural transitions of these proteins in the overcrowded conditions of the membrane-less organelles. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe
Broad-band analysis of X-ray pulsar 2S 1845–024
We present the results of a detailed investigation of the poorly studied X-ray pulsar 2S 1845−024 based on data obtained at the NuSTAR observatory during the type I outburst in 2017. Neither pulse phase-averaged nor phase-resolved spectra of the source show evidence for a cyclotron absorption feature. We also used data obtained from other X-ray observatories (Swift, XMM-Newton and Chandra) to study the spectral properties as a function of orbital phase. The analysis reveals a high hydrogen column density for the source reaching ∼1024 cm−2 around periastron. Using high-quality Chandra data we were able to obtain an accurate localization of 2S 1845−024 at 18h48m16s.8 and Dec. = −2◦25'25".1 (J2000), which allowed us to use infrared (IR) data to roughly classify the optical counterpart of the source as an OB supergiant at a distance of ≳15 kpc.</p
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