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961.
Activation of PhoBR under phosphate‐rich conditions reduces the virulence of Xanthomonas oryzae pv. oryzae
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Dehong Zheng Bingbing Xue Yanan Shao Haoquan Yu Xiaoyan Yao Lifang Ruan 《Molecular Plant Pathology》2018,19(9):2066-2076
The two‐component signal transduction system PhoBR regulates the adaptation to phosphate limitation and the virulence of many animal bacterial pathogens. However, PhoBR in phytopathogens has rarely been investigated. In this study, we found that PhoBR in Xanthomonas oryzae pv. oryzae (Xoo), the pathogen of rice bacterial leaf blight, also regulates the adaptation to phosphate starvation. Unexpectedly, rice leaves infected by the phoBR‐deleted mutant and wild‐type PXO99A showed similar lesions, indicating that PhoBR is unnecessary for the virulence of Xoo. phoBR was found to be silenced during host infection, whereas artificially constitutive PhoBR expression attenuated virulence on host rice and growth in phosphate‐rich media. RNA‐sequencing (RNA‐seq) was then performed to investigate the global effect caused by constitutive PhoBR activation. RNA‐seq and further experiments revealed that the PhoBR regulon in Xoo comprised a wide range of genes. Nutrient transport and metabolism readjustments that resulted from PhoBR regulon activation may be responsible for growth attenuation. Our findings suggest that growth reduction regulated by PhoBR is a fitness cost of adaptation to phosphate starvation. PhoBR in Xoo is activated under phosphate‐limited conditions, which could exist in epiphytic and saprophytic surviving phases, and is strictly repressed within phosphate‐rich host plants to minimize fitness costs. 相似文献
962.
Luminescent properties of novel red‐emitting M7Sn(PO4)6:Eu3+ (M = Sr,Ba) for light‐emitting diodes
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Novel red‐emitting phosphors, Eu3+‐activated M7Sn(PO4)6 (M = Sr, Ba), were synthesized at 1200°C by conventional solid‐state reaction method. The luminescent properties of M7Sn(PO4)6:Eu3+ (M = Sr, Ba) phosphors were investigated, and the critical concentration of the activator (Eu3+) concentration were found to be 0.175 mol and 0.21 mol per formula unit for Sr7‐xSn(PO4)6:xEu3+ and Ba7‐xSn(PO4)6:xEu3+, respectively. These phosphors presented red luminescence under the excitation of 395 or 465 nm, perfectly matching with the emissions wavelength of near‐ultraviolet (UV) light‐emitting diodes (LEDs) and InGaN blue LED. 相似文献
963.
Silica‐modified luminescent LaPO4:Eu@LaPO4@SiO2 core/shell nanorods: Synthesis,structural and luminescent properties
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Anees A. Ansari 《Luminescence》2018,33(1):112-118
Monoclinic‐type tetragonal LaPO4:Eu (core) and LaPO4:Eu@LaPO4 (core/shell) nanorods (NRs) were successfully prepared using a urea‐based co‐precipitation process under ambient conditions. An amorphous silica layer was coated around the luminescent core/shell NRs via the sol–gel process to improve their solubility and colloidal stability in aqueous and non‐aqueous media. The prepared nano‐products were systematically characterized by X‐ray diffraction pattern, transmission electron microscopy, energy dispersive X‐ray analysis, and FTIR, UV/Vis, and photoluminescence spectroscopy to examine their phase purity, crystal phase, surface chemistry, solubility and luminescence characteristics. The length and diameter of the nano‐products were in the range 80–120 nm and 10–15 nm, respectively. High solubility of the silica‐modified core/shell/Si NRs was found for the aqueous medium. The luminescent core NRs exhibited characteristic excitation and emission transitions in the visible region that were greatly affected by surface growth of insulating LaPO4 and silica layers due to the multiphonon relaxation rate. Our luminescence spectral results clearly show a distinct difference in intensities for core, core/shell, and core/shell/Si NRs. Highly luminescent NRs with good solubility could be useful candidates for a variety of photonic‐based biomedical applications. 相似文献
964.
Jia Ding Yuh‐Chieh Lin Jue Liu Jatinkumar Rana Hanlei Zhang Hui Zhou Iek‐Heng Chu Kamila M. Wiaderek Fredrick Omenya Natasha A. Chernova Karena W. Chapman Louis F. J. Piper Shyue Ping Ong M. Stanley Whittingham 《Liver Transplantation》2018,8(21)
Sodium ion batteries have attracted much attention in recent years, due to the higher abundance and lower cost of sodium, as an alternative to lithium ion batteries. However, a major challenge is their lower energy density. In this work, we report a novel multi‐electron cathode material, KVOPO4, for sodium ion batteries. Due to the unique polyhedral framework, the V3+ ? V4+ ? V5+ redox couple was for the first time fully activated by sodium ions in a vanadyl phosphate phase. The KVOPO4 based cathode delivered reversible multiple sodium (i.e. maximum 1.66 Na+ per formula unit) storage capability, which leads to a high specific capacity of 235 Ah kg?1. Combining an average voltage of 2.56 V vs. Na/Na+, a high practical energy density of over 600 Wh kg?1 was achieved, the highest yet reported for any sodium cathode material. The cathode exhibits a very small volume change upon cycling (1.4% for 0.64 sodium and 8.0% for 1.66 sodium ions). Density functional theory (DFT) calculations indicate that the KVOPO4 framework is a 3D ionic conductor with a reasonably, low Na+ migration energy barrier of ≈450 meV, in line with the good rate capability obtained. 相似文献
965.
The present study was designed to evaluate the effect of P. aeruginosa on reproductive potential of male mice via a series of in vitro and in vivo experiments. In vitro studies involved sperm parameters, Mg2+ATPase activity and acrosome status. In vivo study employed male mice which in the right vas deferens received 20?μl of either PBS (Group I) or 104 cfu of P. aeruginosa (Group II). The animals were sacrificed on day 3, 7 and 14 and various parameters viz. body weight, TSI (%), bacterial load, spermiogram {i.e. sperm count, motility (%), viability (%) and morphology}, lipid peroxidation and tissue histopathology were evaluated. The results revealed that cell free supernatant of P. aeruginosa resulted in reduced motility, viability, Mg2+dependent ATPase activity and premature acrosomal loss of mouse spermatozoa in vitro. In vivo study showed that in comparison to group I, group II revealed significant alterations in all the parameters on all the days of sacrifice. Further, when reproductive organs of right and left side of mice in group II were compared, the right side demonstrated more devastating effects in terms of altered TSI (%) of testis and cauda epididymis, higher bacterial counts, azoospermia, increased malondialdehyde levels and severe inflammation in tissue histopathology in comparison to left side where bacteria disseminated in reduced numbers, thereby, resulting in insignificant changes in TSI (%), spermiogram, malondialdehyde levels and tissue histology. This study demonstrates that the colonization of P. aeruginosa in male genital tract could be a risk factor for fertility. 相似文献
966.
Tomohiko Makiyama Satoru Higashi Hiroshi Sakane Satoru Nogami Hiromichi Shirataki 《Experimental cell research》2018,362(2):412-423
Never in mitosis A-related kinase 2A (Nek2A), a centrosomal serine/threonine kinase, is involved in mitotic progression by regulating the centrosome cycle. Particularly, Nek2A is necessary for dissolution of the intercentriole linkage between the duplicated centrosomes prior to mitosis. Nek2A activity roughly parallels its cell cycle-dependent expression levels, but the precise mechanism regulating its activity remains unclear. In this study, we found that γ-taxilin co-localized with Nek2A at the centrosome during interphase and interacted with Nek2A in yeast two-hybrid and pull-down assays and that γ-taxilin regulated centrosome disjunction in a Nek2A-dependent manner. γ-Taxilin depletion increased the number of cells with striking splitting of centrosomes. The precocious splitting of centrosomes induced by γ-taxilin depletion was attenuated by Nek2A depletion, suggesting that γ-taxilin depletion induces the Nek2A-mediated dissolution of the intercentriole linkage between the duplicated centrosomes nevertheless mitosis does not yet begin. Taken together with the result that γ-taxilin protein expression levels were decreased at the onset of mitosis, we propose that γ-taxilin participates in Nek2A-mediated centrosome disjunction as a negative regulator through its interaction with Nek2A. 相似文献
967.
Sudheer Babu Sangeetham Krisztina Huszár Petra Bencsura Antal Nyeste Éva Hunyadi-Gulyás Elfrieda Fodor Ervin Welker 《Journal of molecular biology》2018,430(17):2784-2801
Transmissible spongiform encephalopathies are centered on the conformational transition of the prion protein from a mainly helical, monomeric structure to a β-sheet rich ordered aggregate. Experiments indicate that the main infectious and toxic species in this process are however shorter oligomers, formation of which from the monomers is yet enigmatic. Here, we created 25 variants of the mouse prion protein site-specifically containing one genetically-incorporated para-benzoyl-phenylalanine (pBpa), a cross-linkable non-natural amino acid, in order to interrogate the interface of a prion protein-dimer, which might lie on the pathway of oligomerization. Our results reveal that the N-terminal part of the prion protein, especially regions around position 127 and 107, is integral part of the dimer interface. These together with additional pBpa-containing variants of mPrP might also facilitate to gain more structural insights into oligomeric and fibrillar prion protein species including the pathological variants. 相似文献
968.
Nathan Will Kwangwoon Lee Fatlum Hajredini David H. Giles Rinat R. Abzalimov Michael Clarkson Kevin N. Dalby Ranajeet Ghose 《Journal of molecular biology》2018,430(17):2802-2821
Eukaryotic elongation factor 2 kinase (eEF-2K), the only known calmodulin (CaM)-activated α-kinase, phosphorylates eukaryotic elongation factor 2 (eEF-2) on a specific threonine (Thr-56) diminishing its affinity for the ribosome and reducing the rate of nascent chain elongation during translation. Despite its critical cellular role, the precise mechanisms underlying the CaM-mediated activation of eEF-2K remain poorly defined. Here, employing a minimal eEF-2K construct (TR) that exhibits activity comparable to the wild-type enzyme and is fully activated by CaM in vitro and in cells, and using a variety of complimentary biophysical techniques in combination with computational modeling, we provide a structural mechanism by which CaM activates eEF-2K. Native mass analysis reveals that CaM, with two bound Ca2 + ions, forms a stoichiometric 1:1 complex with TR. Chemical crosslinking mass spectrometry and small-angle X-ray scattering measurements localize CaM near the N-lobe of the TR kinase domain and the spatially proximal C-terminal helical repeat. Hydrogen/deuterium exchange mass spectrometry and methyl NMR indicate that the conformational changes induced on TR by the engagement of CaM are not localized but are transmitted to remote regions that include the catalytic site and the functionally important phosphate binding pocket. The structural insights obtained from the present analyses, together with our previously published kinetics data, suggest that TR, and by inference, wild-type eEF-2K, upon engaging CaM undergoes a conformational transition resulting in a state that is primed to efficiently auto-phosphorylate on the primary activating T348 en route to full activation. 相似文献
969.
Hidetake Nagahara Takahiro Seno Aihiro Yamamoto Hiroshi Obayashi Takuya Inoue Takashi Kida Amane Nakabayashi Yuji Kukida Kazuki Fujioka Wataru Fujii Ken Murakami Masataka Kohno Yutaka Kawahito 《Biochemical and biophysical research communications》2018,495(2):1901-1907
Allograft inflammatory factor-1 (AIF-1) is a protein expressed by macrophages infiltrating the area around the coronary arteries in a rat ectopic cardiac allograft model. We previously reported that AIF-1 is associated with the pathogenesis of rheumatoid arthritis and skin fibrosis in sclerodermatous graft-versus-host disease mice. Here, we used an animal model of bleomycin-induced lung fibrosis to analyze the expression of AIF-1 and examine its function in lung fibrosis. The results showed that AIF-1 was expressed on lung tissues, specifically macrophages, from mice with bleomycin-induced lung fibrosis. Recombinant AIF-1 increased the production of TGF-β which plays crucial roles in the mechanism of fibrosis by mouse macrophage cell line RAW264.7. Recombinant AIF-1 also increased both the proliferation and migration of lung fibroblasts compared with control group. These results suggest that AIF-1 plays an important role in the mechanism underlying lung fibrosis, and may provide an attractive new therapeutic target. 相似文献
970.
Sergey M. Korotkov Svetlana A. Konovalova Vladimir P. Nesterov Irina V. Brailovskaya 《Biochemical and biophysical research communications》2018,495(2):1716-1721
It was earlier shown that the calcium load of rat liver mitochondria in medium containing TlNO3 and KNO3 resulted in the Tl+-induced mitochondrial permeability transition pore (MPTP) opening in the inner membrane. This opening was accompanied by an increase in swelling and membrane potential dissipation and a decrease in state 3, state 4, and 2,4-dinitrophenol-uncoupled respiration. This respiratory decrease was markedly leveled by mersalyl (MSL), the phosphate symporter (PiC) inhibitor which poorly stimulated the calcium-induced swelling, but further increased the potential dissipation. All of these effects of Ca2+ and MSL were visibly reduced in the presence of the MPTP inhibitors (ADP, N-ethylmaleimide, and cyclosporine A). High MSL concentrations attenuated the ability of ADP to inhibit the MPTP. Our data suggest that the PiC can participate in the Tl+-induced MPTP opening in the inner membrane of Ca2+-loaded rat liver mitochondria. 相似文献