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Find video protocols related to scientific articles indexed in Pubmed.
Proteomic Analysis of the Defense Response of Wheat to the Powdery Mildew Fungus, Blumeria graminis f. sp. tritici.
Protein J.
PUBLISHED: 09-28-2014
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Powdery mildew of wheat is caused by Blumeria graminis f. sp. tritici (Bgt). Although many wheat cultivars resistant to this disease have been developed, little is known about their resistance mechanisms. The aim of this study was to identify proteins showing changes in abundance during the resistance response of the wheat line N0308 infected by Bgt. In two-dimensional electrophoresis analyses, 45 spots on the gels showed significant changes in abundance at 24, 48, and 72 h after inoculation, as compared to non-inoculated plants. Of these 45 proteins, 44 were identified by mass spectrometry analysis using the NCBInr database of Triticum aestivum (26 spots) and closely related species in the Triticum genus (18 spots). These proteins were associated with the defense response, photosynthesis, metabolism, and other cellular processes in wheat. Most of the up-regulated proteins were identified as stress- and defense-related proteins. In particular, the product of a specific powdery mildew resistance gene (Pm3b and its homolog) and some other defense- and pathogenesis-related proteins were overexpressed. The resistance gene product mediates the immune response and coordinates other cellular processes during the resistance response to Bgt.
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Large-scale transcriptome comparison reveals distinct gene activations in wheat responding to stripe rust and powdery mildew.
BMC Genomics
PUBLISHED: 07-18-2014
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Stripe rust (Puccinia striiformis f. sp. tritici; Pst) and powdery mildew (Blumeria graminis f. sp. tritici; Bgt) are important diseases of wheat (Triticum aestivum) worldwide. Similar mechanisms and gene transcripts are assumed to be involved in the host defense response because both pathogens are biotrophic fungi. The main objective of our study was to identify co-regulated mRNAs that show a change in expression pattern after inoculation with Pst or Bgt, and to identify mRNAs specific to the fungal stress response.
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Development of a SCAR marker for molecular detection and diagnosis of Tilletia controversa Kühn, the causal fungus of wheat dwarf bunt.
World J. Microbiol. Biotechnol.
PUBLISHED: 04-02-2014
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Tilletia controversa Kühn (TCK) is an important quarantine pathogen that causes wheat dwarf bunt and results in devastating damage to wheat production. The fungus is difficult to be distinguished from T. caries and T. laevis, which cause wheat common bunt, based on morphological, physiological and symptomatological characteristics of the pathogens. The traditional detection of the fungus can be a long and tedious process with poor accuracy. The inter-simple sequence repeat (ISSR) technique has been used for identifying molecular markers for detection of TCK. Of 28 ISSR primers screened, ISSR-859 amplified a specific 678 bp DNA fragment from all TCK isolates but not from any isolates of the common bunt fungi or other pathogenic fungi tested. Based on the fragment sequence, a pair of sequence characterized amplified region (SCAR) primers was designed, which amplified a 372 bp DNA fragment specifically in TCK. The SCAR marker was detected using as low as 1 ng template DNA of TCK, and was also detected using broken teliospores and DNA from asymptomatic wheat samples. We developed the SYBR Green I and TaqMan Green I and TaqMan real-time polymorphism chain reaction methods to detect TCK with the detection limit of 0.1 fg with asymptomatic wheat samples. Further work is needed to develop a rapid test kit for this pathogenic fungus using the designed specific primers.
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Development and discrimination of 12 double ditelosomics in tetraploid wheat cultivar DR147.
Genome
PUBLISHED: 02-26-2014
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As an important group in Triticum, tetraploid wheat plays a significant role in the research of wheat evolution. Several complete aneuploid sets of common wheat have provided valuable tools for genetic and breeding studies, while similar aneuploids of tetraploid wheat are still not well developed. Here, 12 double ditelosomics developed in Triticum turgidum L. var. durum cultivar DR147 (excluding dDT2B and dDT3A) were reported. Hybrids between DR147 and the original double-ditelosomic dDT2B of Langdon lost vigor and died prematurely after the three-leaf stage; therefore, the dDT2B line was not obtained. The cytogenetic behaviors and phenotypic characteristics of each line were detailedly described. To distinguish the entire chromosome complement of tetraploid wheat, the DR147 karyotype was established by fluorescence in situ hybridization (FISH), using the Aegilops tauschii clone pAsl and the barley clone pHvG38 as probes. FISH using a cereal-specific centromere repeat (6C6) probe suggested that all the lines possessed four telosomes, except for 4AS of double-ditelosomic dDT4A, which carried a small segment of the long arm. On the basis of the idiogram of DR147, these lines were successfully discriminated by FISH using the probes pAsl and pHvG38 and were then accurately designated.
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A comparative approach expands the protein-protein interaction node of the immune receptor XA21 in wheat and rice.
Genome
PUBLISHED: 07-12-2013
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The rice (Oryza sativa) OsXA21 receptor kinase is a well-studied immune receptor that initiates a signal transduction pathway leading to resistance to Xanthomonas oryzae pv. oryzae. Two homologs of OsXA21 were identified in wheat (Triticum aestivum): TaXA21-like1 located in a syntenic region with OsXA21, and TaXA21-like2 located in a nonsyntenic region. Proteins encoded by these two wheat genes interact with four wheat orthologs of known OsXA21 interactors. In this study, we screened a wheat yeast-two-hybrid (Y2H) library using the cytosolic portion of TaXA21-like1 as bait to identify additional interactors. Using full-length T. aestivum and T. monococcum proteins and Y2H assays we identified three novel TaXA21-like1 interactors (TaARG, TaPR2, TmSKL1) plus one previously known in rice (TaSGT1). An additional full-length wheat protein (TaCIPK14) interacted with TaXA21-like2 and OsXA21 but not with TaXA21-like1. The interactions of TaXA21-like1 with TmSKL1 and TaSGT1 were also observed in rice protoplasts using bimolecular fluorescence complementation assays. We then cloned the rice homologs of the novel wheat interactors and confirmed that they all interact with OsXA21. This last result suggests that interspecific comparative interactome analyses can be used not only to transfer known interactions from rice to wheat, but also to identify novel interactions in rice.
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Study of the particles structure dependent rheological behavior for polymer nanospheres based shear thickening fluid.
J Colloid Interface Sci
PUBLISHED: 05-13-2013
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A novel kind of shear thickening fluid (STF) was developed via dispersing poly(styrene-acrylic acid) (PS-AA) nanospheres into ethylene glycol (EG). By varying the structure characteristics of the PS-AA particles, STFs with different rheological properties can be obtained. Firstly, the influence of the styrene/acrylic acid ratio on the PS-AA nanospheres was investigated. It was found that the higher ratio often led to the better shear thickening (ST) effects and under the optimum condition the maximum viscosity of the STF could reach to 152Pa s, while the ST effects decreased under further increasing the monomer ratio. Then, the divinyl benzene (DVB) was introduced to increase the cross-link density of the PS-AA. In comparison with the non-cross-link PS-AA nanospheres, the poly(styrene-acrylic acid-divinyl benzene) (PS-AA-DVB) based STFs exhibited much higher ST effects and the maximum viscosity was up to 385Pas when the DVB was only increased to 0.3%. In combination of the rheological properties and the structure characterization, a possible mechanism for the ST behavior was proposed and the influence of the particles characteristics on the mechanical performance of the PS-AA based STF was carefully analyzed.
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Long non-coding genes implicated in response to stripe rust pathogen stress in wheat (Triticum aestivum L.).
Mol. Biol. Rep.
PUBLISHED: 02-06-2013
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The non-protein-coding genes have been reported as a critical control role in the regulation of gene expression in abiotic stress. We previously identified four expressed sequence tags numbered S18 (EL773024), S73 (EL773035), S106 (EL773041) and S108 (EL773042) from a SSH-cDNA library of bread wheat Shaanmai 139 infected with Puccinia striiformis f. sp. tritici (Pst). Here, we isolated four cDNA clones and referred them as TalncRNA18, TalncRNA73, TalncRNA106 and TalncRNA108 (GenBank: KC549675-KC549678). These cDNA separately consisted of 1,393, 667, 449 and 647 nucleotides but without any open reading frame. The alignment result showed that TalncRNA18 is a partial cDNA of E3 ubiquitin-protein ligase UPL1-like gene, TalncRNA73 is an antisense transcript of hypothetical protein, TalncRNA108 is a homolog to RRNA intron-encoded homing endonuclease, and lncRNA106 had no similarly sequence. Quantitative RT-PCR studies confirmed that these four lncRNAs were differentially expressed in three near isogenic lines. TalncRNA108 was significantly stepwise decreased at early stage of inoculation with Pst, while the others were upregulated, especially at 1 and 3 dpi (days post-inoculation). Using Chinese Spring nulli-tetrasomic lines and its ditelosomic lines, TalncRNA73 and TalncRNA108 were located to wheat chromosome 7A and the short arm of chromosome 4B, respectively, while TalncRNA18 and TalncRNA106 were located to chromosome 5B. Comparing the sequence of DNA and cDNA of four lncRNAs with polymerase chain reaction primers, the results showed that all of them have no introns. The kinetics analyses of lncRNAs expression as a result of pathogen challenge in immune resistant genotype indicated that they may play the roles of modulating or silencing the protein-coding gene into pathogen-defence response.
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Isolation and characterization of a wheat IF2 homolog required for innate immunity to stripe rust.
Plant Cell Rep.
PUBLISHED: 01-09-2013
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The wheat eIF2 homolog, TaIF2, is induced by the stripe rust pathogen CYR 32 at an early stage of inoculation and is related to the innate immunity resistance level in wheat. The initiation of translation represents a critical control point in the regulation of gene expression in all organisms. We previously identified an upregulated EST S186 (EL773056) from an SSH-cDNA library of the Shaanmai 139 strain of wheat (Triticum aestivum) infected with Puccinia striiformis (Pst). In the present work, we isolated a cDNA clone and identified it as a wheat IF2 homolog. This cDNA consisted of 1,314 nucleotides and contained an open reading frame of 795 nucleotides encoding a polypeptide of 254 amino acids. The amino acids represent a conserved domain in EF-Tu, mtIF2-II, and mtIF2-Ivc. The alignment result showed that it maybe a partial cDNA of the initiation factor 2/eukaryotic initiation factor 5B (IF2/eIF5B) superfamily gene. Paradoxically, results of a Swiss-model analysis suggesting a low QMEAN Z-score implied that it was a membrane protein. Quantitative RT-PCR studies confirmed that the wheat eIF2 (TaIF2) homolog was differentially expressed in three near-isogenic lines. Critical time points for the induction of resistance by inoculation with Pst CYR32 in YrSM139-1B + YrSM139-2D immune resistance genotype occurred at 1 and 3 dpi (days post-infection). RNAi test showed that the inoculated BSMV-IF2 leaves of Shaanmai 139 showed obvious cell death after 15 days of inoculation with CYR 32. qRT-PCR analysis of the target gene in cDNA samples isolated from BSMV-IF2-Pst, BSMV-0-Pst and Pst infected leaves confirmed that the expression of TaIF2 is suppressed by BSMV-IF2 at 3 dpi. This suggested that TaIF2/eIF5B plays an important role in the mechanism of innate immunity to stripe rust pathogen.
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Probing and tracking organelles in living plant cells.
Protoplasma
PUBLISHED: 10-18-2011
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Intracellular organelle movements and positioning play pivotal roles in enabling plants to proliferate life efficiently and to survive diverse environmental stresses. The elaborate dissection of organelle dynamics and their underlying mechanisms (e.g., the role of the cytoskeleton in organelle movements) largely depends on the advancement and efficiency of organelle tracking systems. Here, we provide an overview of some recently developed tools for labeling and tracking organelle dynamics in living plant cells.
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Magnetic recyclable Ag catalysts with a hierarchical nanostructure.
Nanotechnology
PUBLISHED: 08-18-2011
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This study reports the fabrication of a novel hierarchically structured nanocatalyst system possessing a well-defined nickel silicate (NS) protected Fe(3)O(4) core and a layer of uniform Ag nanoparticles on the NS shell by using a multi-step approach. The multifunctional microparticles show high performance in the reduction of 4-nitrophenol and the rate of the catalytic reaction can be controlled by changing the concentration of nanocatalysts. In particular, there was no visible decrease in the catalytic activity of the reused catalysts even after being recycled five times. Thus the hierarchically structured Fe(3)O(4)@NS particles are very suitable as a catalyst support for catalyst separation and redispersion.
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Immobilization of Pd nanocatalysts on magnetic rattles and their catalytic property.
Dalton Trans
PUBLISHED: 06-30-2011
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Here we report a magnetic composite nanocatalyst (MP@NiSiO/Pd) with a rattle type nanostructure. The nickel silicate shell encapsulated magnetic core (MP@NiSiO) rattle particles were synthesized by using a facile templating method and the Pd nanocrystals with different sizes can be directly immobilized onto the MP@NiSiO rattles without using any surfactant or capping reagents. X-Ray powder Diffraction (XRD) and Transmission Electron Microscopy (TEM) are employed to characterize the rattle type particles. The MP@NiSiO/Pd composites show catalytic activity on the Heck and Suzuki reactions. They can be separated from the reaction system by using a magnet and the catalyst can be cycled at least for 5 times.
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[Determination of sulfonamides, quinolones, benzimidazoles and the metabolites of benzimidazoles in chicken livers by dispersive solid-phase extraction and ultra performance liquid chromatography-tandem mass spectrometry].
Se Pu
PUBLISHED: 05-24-2011
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A method for the determination of 12 sulfonamides, 19 quinolones and 8 benzimidazoles and the metabolites of benzimidazoles in chicken livers by quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed. The samples were extracted with 1% acetic acid-acetonitrile solution, cleaned up with amine (NH2) sorbent and defatted with n-hexane. The identification and quantification were achieved by using electrospray ionization in positive ion mode (ESI+) with multiple reaction monitoring (MRM). The matrix-matched internal standard calibration curves were used for quantitative determination. The linear range was from 5 to 100 microg/kg. The average recoveries and relative standard deviations were 72% - 121% and 1.5% -23.4% respectively in the spiked range of 10 -50 microg/kg. The limits of detection were 5 microg/kg and the limits of quantification were 10 microg/kg for the 39 drugs. The method is simple, rapid, sensitive and accurate. It is suitable for the quantitative determination and confirmation of 12 sulfonamides, 19 quinolones, 8 benzimidazoles and the metabolites of benzimidazoles.
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Application of DNA-based diagnostics in detection of schistosomal DNA in early infection and after drug treatment.
Parasit Vectors
PUBLISHED: 04-01-2011
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Research is now focused on identification of sensitive and specific diagnostic tests for early identification of schistosomal infection and evaluation of chemotherapy in field situations in China.
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Non-invasive vibrational SFG spectroscopy reveals that bacterial adhesion can alter the conformation of grafted "brush" chains on SAM.
Langmuir
PUBLISHED: 03-16-2011
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Understanding bacterial adhesion on a surface is a crucial step to design new materials with improved properties or to control biofilm formation and eradication. Sum Frequency Generation (SFG) vibrational spectroscopy has been employed to study in situ the conformational response of a self-assembled monolayer (SAM) of octadecanethiol (ODT) on a gold film to the adhesion of hydrophilic and hydrophobic ovococcoid model bacteria. The present work highlights vibrational SFG spectroscopy as a powerful and unique non-invasive biophysical technique to probe and control bacteria interaction with ordered surfaces. Indeed, the SFG vibrational spectral changes reveal different ODT SAM conformations in air and upon exposure to aqueous solution or bacterial adhesion. Furthermore, this effect depends on the bacterial cell surface properties. The SFG spectral modeling demonstrates that hydrophobic bacteria flatten the ODT SAM alkyl chain terminal part, whereas the hydrophilic ones raise this ODT SAM terminal part. Microorganism-induced alteration of grafted chains can thus affect the desired interfacial functionality, a result that should be considered for the design of new reactive materials.
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Evolution of the initial hole in vertically vibrated shear thickening fluids.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 01-19-2011
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The apparent viscosity of shear thickening fluid (STF) changes dramatically with the applied shear rate, which is a typical rheological property of STF. Such a rheological property affects the vertically vibrated dynamic property of STF. In order to get a better understanding of the vertically vibrated dynamic properties of STF, the surface instabilities in vertically vibrated STF, which was prepared by suspending polymethylmethacrylate particles in ethylene glycol, are investigated. Above a critical driving acceleration, the surface instability transforms from the disappearance to the fission of the initial hole, which is produced by applying a finite perturbation to the surface. The time required for the initial hole to disappear can be affected by the driving acceleration, vibration frequency, volume fraction, thickness, and shape and size of the perturbation. A possible model is proposed, and the expressions of hydrostatic force and viscous dissipative force are employed to clarify the relationship between disappearance of the hole and shear thickening effect. The fission and spreading follow a hexagonal arrangement. At a higher acceleration, the holes cover the entire surface in a state of disorder. The mechanism for the initial holes evolution in vertically vibrated shear thickening fluids is discussed.
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Temporal augmentation using a polytetrafluoroethylene implant with the assistance of an endoscope.
Aesthetic Plast Surg
PUBLISHED: 01-20-2010
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Expanded polytetrafluoroethylene (e-PTFE), invented by W. L. Gore in the late 1960s, has become a popular material in facial plastic and reconstructive surgery. The use of e-PTFE sheets in the temporal region is reported by some authors and achieving good results. Endoscopic techniques, characterized by small incisions, slight injury, and fewer complications, can be applied in many fields. With the assistance of an endoscope, temporal augmentation with e-PTFE is performed under direct sight, and complications can be reduced. This study aimed to investigate endoscopically assisted temporal augmentation using e-PTFE.
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Can the pectoral fascia integrity be preserved during subfascial breast augmentation through the axillary approach?
Aesthetic Plast Surg
PUBLISHED: 07-22-2009
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Although many authors recently have reported good results with subfascial breast augmentation, it still is controversial whether the integrity of the pectoral fascia can be preserved. Some authors think the pectoral fascia will be broken during the operation because it is thin and weak. Therefore, this study aimed to investigate whether the integrity of the pectoral fascia can be preserved during subfascial breast augmentation through an axillary incision without endoscopic assistance.
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3D-QSAR studies of HDACs inhibitors using pharmacophore-based alignment.
Eur J Med Chem
PUBLISHED: 01-13-2009
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Histone deacetylases (HDACs) enzyme is a promising target for the development of anticancer drugs. The enzyme-bound conformation of Trichostatin A (TSA) (PDB ID:1C3R) as an inhibitor of HDACs was used to manually construct a pharmacophore model. This model was then successfully used to identify the bioactive conformation and align flexible and structurally diverse molecules. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on hydroxamate-based HDACs inhibitors based on phamacophore alignment. The best predictions were obtained with CoMFA standard model (q(2) = 0.726, r(2) = 0.998) and CoMSIA model combined with steric, electrostatic, hydrophobic, hydrogen bond donor and acceptor fields (q(2) = 0.610, r(2) = 0.995). Both of the models were validated by an external test set, which gave a satisfactory predictive r(2) value of 0.800 and 0.732, respectively. Graphical interpretation of the results revealed important structural features of the inhibitors related to the active site of HDACs. The results may be exploited for further design and virtual screening for some novel HDACs inhibitors.
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Competition of bovine serum albumin adsorption and bacterial adhesion onto surface-grafted ODT: in situ study by vibrational SFG and fluorescence confocal microscopy.
Langmuir
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The interaction of hydrophilic and hydrophobic ovococcoid bacteria and bovine serum albumin (BSA) proteins with a well ordered surface of octadecanethiol (ODT) self assembled monolayer (SAM) has been studied in different situations where proteins were either preadsorbed on ODT or adsorbed simultaneously with bacterial adhesion as in life conditions. The two situations lead to very different antimicrobial behavior. Bacterial adhesion on preadsorbed BSA is very limited, while the simultaneous exposure of ODT SAM to proteins and bacteria lead to a markedly weaker antimicrobial effect. The combination of sum frequency generation spectroscopy and fluorescence confocal microscopy experiments allow one to draw conclusions on the factors that govern the ODT SAM or BSA film interaction with bacteria at the molecular level. On the hydrophobic ODT surface, interaction with hydrophobic or hydrophilic biomolecules results in opposite effects on the SAM, namely, a flattening or a raise of the terminal methyl groups of ODT. On an amphiphilic BSA layer, the bacterial adhesion strength is weakened by the negative charges carried by both BSA and bacteria. Surprisingly, preadsorbed BSA that cover part of the bacteria cell walls increase the adhesion strength to the BSA film and reduce hydrophobic interactions with the ODT SAM. Finally, bacterial adhesion on a BSA film is shown to modify the BSA proteins in some way that change their interaction with the ODT SAM. The antimicrobial effect is much stronger in the case of a preadsorbed BSA layer than when BSA and bacteria are in competition to colonize the ODT SAM surface.
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A novel immunodiagnostic assay to detect serum antibody response against selected soluble egg antigen fractions from Schistosoma japonicum.
PLoS ONE
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Schistosomiasis japonica remains a real threat to public health in China. The currently used immunodiagnostic assays are sensitive and have a certain degree of specificity, however, they all use complex crude antigens, are based on detection of schistosome-specific antibodies, and have been shown to cross-react with other parasitic diseases. Therefore, these assays cannot be used to evaluate chemotherapy efficacy. The development of highly sensitive and highly specific immunodiagnostic techniques that can monitor the decline of antibodies specific for S. japonica will be extremely valuable as part of the ongoing strategy to control schistosomiasis in endemic areas. Here we report on the identification of unique fraction antigens of soluble egg antigen (SEA) to which the antibodies disappear 7 weeks after effective treatment. Furthermore, we use these SEA fractions to develop a modified assay with both high sensitivity and specificity.
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Molecular mapping of a powdery mildew resistance gene in common wheat landrace Baihulu and its allelism with Pm24.
Theor. Appl. Genet.
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Powdery mildew is one of the most devastating diseases of wheat in areas with cool and maritime climates. Chinese wheat landrace Baihulu confers a high level of resistance against a wide range of Blumeria graminis DC f. sp. tritici (Bgt) races, especially those currently prevailing in Shaanxi. The objectives of this study were to determine the chromosome bin location of the mlbhl gene from Baihulu and its allelism with Pm24. To investigate the inheritance of powdery mildew resistance and detect adjacent molecular markers, we constructed a segregating population of 301 F(2) plants and corresponding F(2:3) families derived from Baihulu/Shaanyou 225. Genetic analysis revealed that a single dominant gene was responsible for seedling stage powdery mildew resistance in Baihulu. A genetic map comprising Xgwm106, Xgwm337, Xgwm1675, Xgwm603, Xgwm789, Xbarc229, Xgpw4503, Xcfd72, Xcfd83, Xcfd59, Xcfd19, and mlbhl spanned 28.2 cM on chromosome 1D. Xgwm603/Xgwm789 and Xbarc229 were flanking markers tightly linked to mlbhl at genetic distances of 1.5 and 1.0 cM, respectively. The mlbhl locus was located in chromosome bin 1DS 0.59-1.00 delimited by the SSR markers Xgwm337 and Xbarc229. When tested with a differential array of 23 Bgt isolates Baihulu displayed a response pattern that was clearly distinguishable from that of Chiyacao and varieties or lines possessing documented Pm genes. Allelism analysis indicated that mlbhl is a new gene, either allelic or closely linked with Pm24. The new gene was designated Pm24b.
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Population analysis of the Fusarium graminearum species complex from wheat in China show a shift to more aggressive isolates.
PLoS ONE
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A large number of Fusarium isolates was collected from blighted wheat spikes originating from 175 sampling sites, covering 15 provinces in China. Species and trichothecene chemotype determination by multilocus genotyping (MLGT) indicated that F. graminearum s. str. with the 15-acetyl deoxynivalenol (15ADON) chemotype and F. asiaticum with either the nivalenol (NIV) or the 3-acetyl deoxynivalenol (3ADON) chemotype were the dominant causal agents. Bayesian model-based clustering with allele data obtained with 12 variable number of tandem repeats (VNTR) markers, detected three genetic clusters that also show distinct chemotypes. High levels of population genetic differentiation and low levels of effective number of migrants were observed between these three clusters. Additional genotypic analyses revealed that F. graminearum s. str. and F. asiaticum are sympatric. In addition, composition analysis of these clusters indicated a biased gene flow from 3ADON to NIV producers in F. asiaticum. In phenotypic analyses, F. asiaticum that produce 3ADON revealed significant advantages over F. asiaticum that produce NIV in pathogenicity, growth rate, fecundity, conidial length, trichothecene accumulation and resistance to benzimidazole. These results suggest that natural selection drives the spread of a more vigorous, more toxigenic pathogen population which also shows higher levels of fungicide resistance.
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Superparamagnetic Ag@Fe3O4 core-shell nanospheres: fabrication, characterization and application as reusable nanocatalysts.
Dalton Trans
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Superparamagnetic Ag@Fe(3)O(4) nanospheres with core-shell nanostructures have been prepared by a facile one-pot method. The diameter of the as-synthesized nanospheres was about 200 nm and the core sizes were between 50 and 100 nm. By varying the concentrations, particles with tunable core size and total size are successfully achieved. Time dependent experiments were constructed to investigate the synthesis mechanism, which indicated that the present method corresponded to an Ostwald ripening progress. The BET area of the core-shell nanospheres is about 22.6 m(2)/g and this result indicates that the product shows a porous character. The saturated magnetization of the superparamagnetic Ag@Fe(3)O(4) nanospheres is 27.4 emu g(-1) at room temperature, which enables them to be recycled from the solution by simply applying a small magnet. Due to the unique nanostructure, these particles show high performance in catalytic reduction of 4-nitrophenol and can be used as reusable nanocatalysts.
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High-density mapping and marker development for the powdery mildew resistance gene PmAS846 derived from wild emmer wheat (Triticum turgidum var. dicoccoides).
Theor. Appl. Genet.
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Powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important foliar disease of wheat worldwide. The dominant powdery mildew resistance gene PmAS846 was transferred to the hexaploid wheat lines N9134 and N9738 from wild emmer wheat (Triticum dicoccoides) in 1995, and it is still one of the most effective resistance genes in China. A high resolution genetic map for PmAS846 locus was constructed using two F(2) populations and corresponding F(2:3) families developed from the crosses of N9134/Shaanyou 225 and N9738/Huixianhong. Synteny between wheat and Brachypodium distachyon and rice was used to develop closely linked molecular markers to reduce the genetic interval around PmAS846. Twenty-six expressed sequence tag-derived markers were mapped to the PmAS846 locus. Five markers co-segregated with PmAS846 in the F(2) population of N9134/Shaanyou 225. PmAS846 was physically located to wheat chromosome 5BL bin 0.75-0.76 within a gene-rich region. The markers order is conserved between wheat and Brachypodium distachyon, but rearrangements are present in rice. Two markers, BJ261635 and CJ840011 flanked PmAS846 and narrowed PmAS846 to a region that is collinear with 197 and 112 kb genomic regions on Brachypodium chromosome 4 and rice chromosome 9, respectively. The genes located on the corresponding homologous regions in Brachypodium, rice and barley could be considered for further marker saturation and identification of potential candidate genes for PmAS846. The markers co-segregating with PmAS846 provide a potential target site for positional cloning of PmAS846, and can be used for marker-assisted selection of this gene.
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The fabrication and cell culture of three-dimensional rolled scaffolds with complex micro-architectures.
Biofabrication
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Cell cultures for tissue engineering are traditionally prepared on two-dimensional or three-dimensional scaffolds with simple pores; however, this limits mass transportation, which is necessary for cell viability and function. In this paper, an innovative method is proposed for fabricating porous scaffolds with designed complex micro-architectures. Channels devised by computer-aided design were used to simulate features of blood vessels in native rat liver. Rapid prototyping and microreplication were used to produce a negative polydimethylsiloxane mold, and then a planar porous scaffold with predefined microchannel parameters was obtained by freeze-drying a silk fibroin/gelatin solution of an optimized concentration. After seeding with rat primary hepatocytes, the planar scaffold was rolled up to build spatial channels. By reconstructing the three-dimensional channel model in the scaffold in the form of micro-computed topography data and observing the cross-sections of the scroll, we confirmed that the bent channels were still interconnected, with restricted deviations. A comparison of the primary hepatocyte culture in the scaffolds with and without the devised channels proved that our design influenced cell organization and improved cell survival and proliferation. This method can be used for the construction of complex tissues for implantation and for culturing cells in vitro for biological tests and observations.
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Wheat stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici.
Mol. Plant Pathol.
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Stripe (yellow) rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a serious disease of wheat occurring in most wheat areas with cool and moist weather conditions during the growing season. The basidiomycete fungus is an obligate biotrophic parasite that is difficult to culture on artificial media. Pst is a macrocyclic, heteroecious fungus that requires a living host (wheat/grasses, Berberis/Mahonia spp.) to complete the asexual and sexual phases of its life cycle, respectively. Urediniospores have the capacity for wind dispersal over long distances which may, under high inoculum pressure, extend to thousands of kilometers from initial infection sites. Stripe rust, which is considered the current major rust disease affecting winter cereal production across the world, has been intensively studied for over a century. This review summarizes current knowledge of the Pst /wheat pathosystem with emphasis on the life cycle, uredinial infection process, population biology of the pathogen, genes for stripe rust resistance in wheat, and molecular perspectives of wheat-Pst interactions.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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