769 research outputs found
Gene transcription analysis during interaction between potato and Ralstonia solanacearum
Bacterial wilt (BW) caused by Ralstonia solanacearum (Rs) is an important quarantine disease that spreads worldwide and infects hundreds of plant species. The BW defense response of potato is a complicated continuous process, which involves transcription of a battery of genes. The molecular mechanisms of potato-Rs interactions are poorly understood. In this study, we combined suppression subtractive hybridization and macroarray hybridization to identify genes that are differentially expressed during the incompatible interaction between Rs and potato. In total, 302 differentially expressed genes were identified and classified into 12 groups according to their putative biological functions. Of 302 genes, 81 were considered as Rs resistance-related genes based on the homology to genes of known function, and they have putative roles in pathogen recognition, signal transduction, transcription factor functioning, hypersensitive response, systemic acquired resistance, and cell rescue and protection. Additionally, 50 out of 302 genes had no match or low similarity in the NCBI databases, and they may represent novel genes. Of seven interesting genes analyzed via RNA gel blot and semi-quantitative RT-PCR, six were induced, one was suppressed, and all had different transcription patterns. The results demonstrate that the response of potato against Rs is rapid and involves the induction of numerous various genes. The genes identified in this study add to our knowledge of potato resistance to Rs
Study of the Anti-Proliferative Activity of 5-Substituted 4,7-Dimethoxy-1,3-Benzodioxole Derivatives of SY-1 from Antrodia camphorata on Human COLO 205 Colon Cancer Cells
A set of 10 4,7-dimethoxy-1,3-benzodioxole derivatives based on a lead compound previously discovered by our group, SY-1, which was isolated from Antrodia camphorata, were evaluated for their in vitro inhibitory activity on human colorectal carcinoma cells (COLO 205). Structure-activity relationship studies of the 10 compounds indicated the importance of the chain length of the alkyl group at the 5-position, and the 2-propenyl substituent named “apiole” exhibited the most potent inhibitory activity. In the present study, we demonstrate that the SY-1 analogue “apiole” decreased the proliferation of COLO 205 cells, but not that of normal human colonic epithelial cells (FHC). The G0/G1 cell cycle arrest induced by apiole (75–225 μM) was associated with significantly increased levels of p53, p21 and p27 and decreased levels of cyclin D1. Concerning COLO 205 cell apoptosis, apiole (>150 μM) treatment significantly increased the levels of cleaved caspases 3, 8, 9 and bax/bcl-2 ratio and induced ladder formation in DNA fragmentation assay and sub-G1 peak in flow cytometry analysis. These findings suggest that apiole can suppress COLO 205 cell growth; however, the detailed mechanisms of these processes require further investigation
Two consecutive dural arteriovenous fistulae in a child: a case report of successful treatment with gamma knife radiosurgery
Introduction The occurrence of dural arteriovenous fistulae in children is quite rare. Endovascular embolization is typically the first line treatment. In general, Gamma Knife radiosurgery is used as adjuvant treatment and seldom performed as the first line treatment in children. Discussion We report a case of a 27-month-old girl who presented with an initial dural arteriovenous fistula (AVF) located at anterior base of the left middle cranial fossa. She subsequently developed another dural AVF over the left transverse-sigmoid sinus region 2 years later. Conclusion Both fistulae were successfully obliterated with Gamma Knife radiosurgery
Comparative analysis of full genomic sequences among different genotypes of dengue virus type 3
<p>Abstract</p> <p>Background</p> <p>Although the previous study demonstrated the envelope protein of dengue viruses is under purifying selection pressure, little is known about the genetic differences of full-length viral genomes of DENV-3. In our study, complete genomic sequencing of DENV-3 strains collected from different geographical locations and isolation years were determined and the sequence diversity as well as selection pressure sites in the DENV genome other than within the E gene were also analyzed.</p> <p>Results</p> <p>Using maximum likelihood and Bayesian approaches, our phylogenetic analysis revealed that the Taiwan's indigenous DENV-3 isolated from 1994 and 1998 dengue/DHF epidemics and one 1999 sporadic case were of the three different genotypes – I, II, and III, each associated with DENV-3 circulating in Indonesia, Thailand and Sri Lanka, respectively. Sequence diversity and selection pressure of different genomic regions among DENV-3 different genotypes was further examined to understand the global DENV-3 evolution. The highest nucleotide sequence diversity among the fully sequenced DENV-3 strains was found in the nonstructural protein 2A (mean ± SD: 5.84 ± 0.54) and envelope protein gene regions (mean ± SD: 5.04 ± 0.32). Further analysis found that positive selection pressure of DENV-3 may occur in the non-structural protein 1 gene region and the positive selection site was detected at position 178 of the NS1 gene.</p> <p>Conclusion</p> <p>Our study confirmed that the envelope protein is under purifying selection pressure although it presented higher sequence diversity. The detection of positive selection pressure in the non-structural protein along genotype II indicated that DENV-3 originated from Southeast Asia needs to monitor the emergence of DENV strains with epidemic potential for better epidemic prevention and vaccine development.</p
Compression Deformation Behavior and Processing Map of Pure Copper
To reveal compression deformation behavior of pure copper, the deformation characteristics of pure copper have been investigated by means of compression tests in the temperature range of 400–900°C and strain rate range of 0.001–1 s⁻¹. The results show that the flow stress of pure copper increases with increasing strain rate and decreasing deformation temperature, which is characterized by work-hardening, dynamic recovery, dynamic recrystallization, and secondary work-hardening, etc. The activation energy of hot deformation is associated with deformation temperature and strain rate, and the average activation energy is calculated to be 303.8 kJ/mol. The flow stress prediction model based on GA+BP possess, is in very good agreement with the true stress curve, which is of significance to the guidance of hot working of pure copper. The flow instability occurs in the intermediate strain rate region (0.01–0.1 s⁻¹) base on the analysis of processing map, the high power dissipation correspond to the dynamic recrystallization. Appropriate reducing the deformation temperature or increasing the strain rate is beneficial for the grain refinement in the steady-state region of the processing map
Building a reduced dictionary of relevant perfusion patterns from CEUS data for the classification of testis lesions
Radical orchifunicolectomy has traditionally been the main clinical treatment for small testicular masses (STMs); however STMs represent a constantly increasing and often incidental finding. Since many of them result benign, a more conservative testis-sparing surgery was proposed, but it requires a preliminary differentiation between benign and malignant masses: this however remains challenging. Although common understanding in radiology and oncology is that perfusion patterns might provide a useful information about the type of masses, no guidelines or consensus is available for the differentiation of STMs. We propose to build a dictionary of relevant perfusion patterns, extracted using non-negative matrix factorization on pixel-wise time-intensity curves from contrast-enhanced ultrasound data. When data from a lesion are reconstructed using this dictionary, a vector containing the frequency of utilization of each pattern can be used as a tissue signature. Using this signature, a support vector machine classifier has been trained, and the cross validated accuracy reached 100% in our pilot cohort
Subprocess Size in Hard Exclusive Scattering
The interaction region of hard exclusive hadron scattering can have a large
transverse size due to endpoint contributions, where one parton carries most of
the hadron momentum. The endpoint region is enhanced and can dominate in
processes involving multiple scattering and quark helicity flip. The endpoint
Fock states have perturbatively short lifetimes and scatter softly in the
target. We give plausible arguments that endpoint contributions can explain the
apparent absence of color transparency in fixed angle exclusive scattering and
the dimensional scaling of transverse rho photoproduction at high momentum
transfer, which requires quark helicity flip. We also present a quantitative
estimate of Sudakov effects.Comment: 16 pages, 4 figures, JHEP style; v2: quantitative estimate of Sudakov
effects and more detailed discussion of endpoint behaviour of meson
distribution amplitude added, few other clarifications, version to appear in
Phys. Rev.
Information strategy failure:personal interaction success, in urban residential food waste segregation
AbstractDirect measurements were taken of residential food waste sorting in a sample from over 5000 communities (5 million households) assigned to a pilot program delivered by government branches in Shanghai which relied on an information strategy for implementation. The results are compared to a population of N = 36 similar communities (36,000 households) assigned to a different program which involved considerable personal interaction. The results show that the information–based program communities did not noticeably sort their waste, whereas those given personal interaction approaches were very successful, with purity rates of 95%(8) and extra costs of about 50 RMB (8 USD) per household. This is a rare direct comparison of two different programs at such large scales, 6–36 months after launch, and suggests that personal interaction approaches should be considered by policy makers. Qualitative key informant interviews yielded data on each program's activities, which provide suggestions for further studies of the underlying behaviour change determinants involved
An attempt to understand exclusive pi+ electroproduction
Hard exclusive pi+ electroproduction is investigated within the handbag
approach. The prominent role of the pion-pole contribution is demonstrated. It
is also shown that the experimental data require a twist-3 effect which ensues
from the helicity-flip generalized parton distribution H_T and the twist-3 pion
wave function. The results calculated from this handbag approach are compared
in detail with the experimental data on cross sections and spin asymmetries
measured with a polarized target. It is also commented on consequences of this
approach for exclusive \pi^0 and vector-meson electroproduction.Comment: 35 pages, 12 figures, using Latex, a number of additional comments
have been included in the text, e.g. in paragraph above (3) or at end of
sect.
The longitudinal cross section of vector meson electroproduction
We analyze electroproduction of light vector mesons (V=rho, phi and omega) at
small Bjorken-x in the handbag approach in which the process factorizes into
general parton distributions and partonic subprocesses. The latter are
calculated in the modified perturbative approach where the transverse momenta
of the quark and antiquark forming the vector meson are retained and Sudakov
suppressions are taken into account. Modeling the generalized parton
distributions through double distributions and using simple Gaussian
wavefunctions for the vector mesons, we compute the longitudinal cross sections
at large photon virtualities. The results are in fair agreement with the
findings of recent experiments performed at HERA and HERMES.Comment: 27 pages, 20 figures, using LATEX with graphic
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