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Rika Kamei Mana Miyakoda Takahiko Tamura Daisuke Kimura Kiri Honma Kazumi Kimura Katsuyuki Yui 《Microbiology and immunology》2013,57(3):213-223
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Wen‐Wen Wu Sha‐Sha He Yu‐Yan An Rong‐Xiang Cao Yong‐Ping Sun Quan Tang Liang‐Ju Wang 《Physiologia plantarum》2019,167(1):5-20
To explore the mechanisms of 5‐aminolevulinic acid (ALA)‐improved plant salt tolerance, strawberries (Fragaria × ananassa Duch. cv. ‘Benihoppe’) were treated with 10 mg l?1 ALA under 100 mmol l?1 NaCl stress. We found that the amount of Na+ increased in the roots but decreased in the leaves. Laser scanning confocal microscopy (LSCM) observations showed that ALA‐induced roots had more Na+ accumulation than NaCl alone. Measurement of the xylem sap revealed that ALA repressed Na+ concentrations to a large extent. The electron microprobe X‐ray assay also confirmed ALA‐induced Na+ retention in roots. qRT‐PCR showed that ALA upregulated the gene expressions of SOS1 (encoding a plasma membrane Na+/H+ antiporter), NHX1 (encoding a vacuolar Na+/H+ antiporter) and HKT1 (encoding a protein of high‐affinity K+ uptake), which are associated with Na+ exclusion in the roots, Na+ sequestration in vacuoles and Na+ unloading from the xylem vessels to the parenchyma cells, respectively. Furthermore, we found that ALA treatment reduced the H2O2 content in the leaves but increased it in the roots. The exogenous H2O2 promoted plant growth, increased root Na+ retention and stimulated the gene expressions of NHX1, SOS1 and HKT1. Diphenyleneiodonium (DPI), an inhibitor of H2O2 generation, suppressed the effects of ALA or H2O2 on Na+ retention, gene expressions and salt tolerance. Therefore, we propose that ALA induces H2O2 accumulation in roots, which mediates Na+ transporter gene expression and more Na+ retention in roots, thereby improving plant salt tolerance. 相似文献
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Andrew Shaker Elissa Currie Joël M.J. Tan Jorik van Rijn Darren E. Higgins John H. Brumell 《Cellular microbiology》2017,19(3)
Type I interferons (IFNs) play a critical role in antiviral immune responses, but can be deleterious to the host during some bacterial infections. Listeria monocytogenes (Lm) induces a type I IFN response by activating cytosolic antiviral surveillance pathways. This is beneficial to the bacteria as mice lacking the type I IFN receptor (IFNAR1?/?) are resistant to systemic infection by Lm. The mechanisms by which type I IFNs promote Lm infection are unclear. Here, we show that IFNAR1 is required for dissemination of Lm within infection foci in livers of infected mice and for efficient cell‐to‐cell spread in vitro in macrophages. IFNAR1 promotes ActA polarization and actin‐based motility in the cytosol of host cells. Our studies suggest type I IFNs directly impact the intracellular life cycle of Lm and provide new insight into the mechanisms used by bacterial pathogens to exploit the type I IFN response. 相似文献
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Jae Hyeon Jo Ji Ung Choi Min Kyung Cho Yauhen Aniskevich Hyungsub Kim Genady Ragoisha Eugene Streltsov Jongsoon Kim Seung‐Taek Myung 《Liver Transplantation》2019,9(22)
Nanosized hollandite‐type VO1.75(OH)0.5 is introduced as a novel cathode material for Na‐ion batteries. Structural investigation based on X‐ray diffraction and Rietveld refinement suggests the presence of numerous vacant sites for Na+ intercalation in the VO1.75(OH)0.5 structure. All of the possible Na+ sites and tunnel‐type Na+ diffusion pathways along the c‐axis are confirmed by bond‐valence‐sum analyses. The nanosized hollandite‐type VO1.75(OH)0.5 delivers an unexpectedly high specific capacity of ≈351 mAh g?1 at 15.5 mA g?1 in the voltage range of 1.0–3.7 V (vs Na+/Na), which agrees well with the results predicted by first‐principles calculations. In addition, combined studies using first‐principles calculations and several experimental techniques including in situ operando X‐ray diffraction and ex situ X‐ray absorption spectroscopy confirm that the nanosized hollandite‐type VO1.75(OH)0.5 undergoes a single‐phase reaction with a capacity retention of 71% over 200 cycles. Furthermore, the open structure and nanosized particles of hollandite‐type VO1.75(OH)0.5 contribute to its excellent power capability with 56% of the capacity measured at 0.05 C being delivered at 7 C. 相似文献
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Functional analysis of the cya promoter of Bordetella pertussis 总被引:3,自引:0,他引:3
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Irene Bianconi Lluis Sempere Patima Permpoonpattana Karen Smith Marcin Dembek Sisareuth Tan Marie‐Clémence Brisson Alain R. Brisson Neil F. Fairweather Simon M. Cutting 《Molecular microbiology》2014,92(5):1025-1038
The BclA protein is a major component of the outermost layer of spores of a number of bacterial species and Clostridium difficile carries three bclA genes. Using insertional mutagenesis each gene was characterized and spores devoid of these proteins had surface aberrations, reduced hydrophobicity and germinated faster than wild‐type spores. Therefore the BclA proteins were likely major components of the spore surface and when absent impaired the protective shield effect of this outermost layer. Analysis of infection and colonization in mice and hamsters revealed that the 50% infectious dose (ID50) of spores was significantly higher (2‐logs) in the bclA1? mutant compared to the isogenic wild‐type control, but that levels of toxins (A and B) were indistinguishable from animals dosed with wild‐type spores. bclA1? spores germinated faster than wild‐type spores yet mice were less susceptible to infection suggesting that BclA1 must play a key role in the initial (i.e. pre‐spore germination) stages of infection. We also show that the ID50 was higher in mice infected with R20291, a ‘hypervirulent’ 027 strain, that carries a truncated BclA1 protein. 相似文献
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Thomas H. Reilly III Alexander W. Hains Hsiang‐Yu Chen Brian A. Gregg 《Liver Transplantation》2012,2(4):455-460
Solid films of a water‐soluble dicationic perylene diimide salt, perylene bis(2‐ethyltrimethylammonium hydroxide imide), Petma+OH?, are strongly doped n‐type by dehydration and reversibly de‐doped by hydration. The hydrated films consist almost entirely of the neutral perylene diimide, PDI, while the dehydrated films contain ~50% PDI anions. The conductivity increases by five orders of magnitude upon dehydration, probably limited by film roughness, while the work function decreases by 0.74 V, consistent with an n‐type doping density increase of ~12 orders of magnitude. Remarkably, the PDI anions are stable in dry air up to 120 °C. The work function of the doped film, ? (3.96 V vs. vacuum), is unusually negative for an O2‐stable contact. Petma+OH? is also characterized as an interfacial layer, IFL, in two different types of organic photovoltaic cells. Results are comparable to state of the art cesium carbonate IFLs, but may improve if film morphology can be better controlled. The films are stable and reversible over many months in air and light. The mechanism of this unusual self‐doping process may involve the change in relative potentials of the ions in the film caused by their deshielding and compaction as water is removed, leading to charge transfer when dry. 相似文献
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Yun‐Zhen Xu Ni‐Ni Guo Zong‐Ming Zheng Xian‐Jin Ou Hong‐Juan Liu De‐Hua Liu 《Biotechnology and bioengineering》2009,104(5):965-972
Klebsiella pneumoniae HR526, a new isolated 1,3‐propanediol (1,3‐PD) producer, exhibited great productivity. However, the accumulation of lactate in the late‐exponential phase remained an obstacle of 1,3‐PD industrial scale production. Hereby, mutants lacking D ‐lactate pathway were constructed by knocking out the ldhA gene encoding fermentative D ‐lactate dehydrogenase (LDH) of HR526. The mutant K. pneumoniae LDH526 with the lowest LDH activity was studied in aerobic fed‐batch fermentation. In experiments using pure glycerol as feedstock, the 1,3‐PD concentrations, conversion, and productivity increased from 95.39 g L?1, 0.48 and 1.98 g L?1 h?1 to 102. 06 g L?1, 0.52 mol mol?1 and 2.13 g L?1 h?1, respectively. The diol (1,3‐PD and 2,3‐butanediol) conversion increased from 0.55 mol mol?1 to a maximum of 0.65 mol mol?1. Lactate would not accumulate until 1,3‐PD exceeded 84 g L?1, and the final lactate concentration decreased dramatically from more than 40 g L?1 to <3 g L?1. Enzymic measurements showed LDH activity decreased by 89–98% during fed‐batch fermentation, and other related enzyme activities were not affected. NADH/NAD+ enhanced more than 50% in the late‐exponential phase as the D ‐lactate pathway was cut off, which might be the main reason for the change of final metabolites concentrations. The ability to utilize crude glycerol from biodiesel process and great genetic stability demonstrated that K. pnemoniae LDH526 was valuable for 1,3‐PD industrial production. Biotechnol. Bioeng. 2009; 104: 965–972. © 2009 Wiley Periodicals, Inc. 相似文献
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Elma Lima Leite Arthur Gautron Martine Deplanche Aurlie Nicolas Jordane Ossemond Minh‐Thu Nguyen Fillipe L. R. do Carmo David Gilot Vasco Azevedo Friedrich Gtz Yves Le Loir Michael Otto Nadia Berkova 《Cellular microbiology》2020,22(8)
Staphylococcus aureus, a versatile Gram‐positive bacterium, is the main cause of bone and joint infections (BJI), which are prone to recurrence. The inflammasome is an immune signaling platform that assembles after pathogen recognition. It activates proteases, most notably caspase‐1 that proteolytically matures and promotes the secretion of mature IL‐1β and IL‐18. The role of inflammasomes and caspase‐1 in the secretion of mature IL‐1β and in the defence of S. aureus‐infected osteoblasts has not yet been fully investigated. We show here that S. aureus‐infected osteoblast‐like MG‐63 but not caspase‐1 knock‐out CASP1 ?/?MG‐63 cells, which were generated using CRISPR‐Cas9 technology, activate the inflammasome as monitored by the release of mature IL‐1β. The effect was strain‐dependent. The use of S. aureus deletion and complemented phenole soluble modulins (PSMs) mutants demonstrated a key role of PSMs in inflammasomes‐related IL‐1β production. Furthermore, we found that the lack of caspase‐1 in CASP1 ?/?MG‐63 cells impairs their defense functions, as bacterial clearance was drastically decreased in CASP1 ?/? MG‐63 compared to wild‐type cells. Our results demonstrate that osteoblast‐like MG‐63 cells play an important role in the immune response against S. aureus infection through inflammasomes activation and establish a crucial role of caspase‐1 in bacterial clearance. 相似文献
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A. Gopalakrishnan M. Rajkumar M. M. Rahman J. Sun P. J. Antony B. A. Venmathi maran J. P. Trilles 《Zeitschrift fur angewandte Ichthyologie》2014,30(1):251-253
Length–weight relationships and condition factors of wild, cultured, and cultured loose‐shell affected Penaeus monodon (2,609 specimens total) were studied from March to August 2007. The regression equation for healthy cultured shrimps was log W = ?1.811 + 2.721 log L (r2 = 0.71); log W = ?1.444 + 2.485 log L (r2 = 0.91) for wild shrimps; and log W = ?1.112 + 2.237 log L (r2 = 0.92) for loose‐shell affected shrimps. All shrimps showed negative allometric growth, although ancova indicated significant differences (P < 0.05) among them. This study presents the first known reference dealing with LWRs and condition factors of cultured, wild and loose‐shell affected P. monodon. 相似文献
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3‐Fucosyllactose (3‐FL), one of the major oligosaccharides in human breast milk, is produced in engineered Escherichia coli. In order to search for a good α‐1,3‐fucosyltransferase, three bacterial α‐1,3‐fucosyltransferases are expressed in engineered E. coli deficient in β‐galactosidase activity and expressing the essential enzymes for the production of guanosine 5′‐diphosphate‐l ‐fucose, the donor of fucose for 3‐FL biosynthesis. Among the three enzymes tested, the fucT gene from Helicobacter pylori National Collection of Type Cultures 11637 gives the best 3‐FL production in a simple batch fermentation process using glycerol as a carbon source and lactose as an acceptor. In order to use glucose as a carbon source, the chromosomal ptsG gene, considered the main regulator of the glucose repression mechanism, is disrupted. The resulting E. coli strain of ?LP‐YA+FT shows a much lower performance of 3‐FL production (4.50 g L?1) than the ?L‐YA+FT strain grown in a glycerol medium (10.7 g L?1), suggesting that glycerol is a better carbon source than glucose. Finally, the engineered E. coli ?LW‐YA+FT expressing the essential genes for 3‐FL production and blocking the colanic acid biosynthetic pathway (?wcaJ) exhibits the highest concentration (11.5 g L?1), yield (0.39 mol mol?1), and productivity (0.22 g L?1 h) of 3‐FL in glycerol‐limited fed‐batch fermentation. 相似文献
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S Ramadasappa AK Rai RS Jaat A Singh R Rai 《World journal of microbiology & biotechnology》2012,28(4):1681-1690
Tomato (Lycopersicon esculentum) is important widely grown vegetable in India and its productivity is affected by bacterial wilt disease infection caused
by Ralstonia solanacearum. To prevent this disease infection a study was conducted to isolate and screen effective plant growth promoting rhizobacteria
(PGPR) antagonistic to R. solanacearum. A total 297 antagonistic bacteria were isolated through dual culture inoculation technique, out of which forty-two antagonistic
bacteria were found positive for phlD gene by PCR amplification using two primer sets Phl2a:Phl2b and B2BF:BPR4. The genetic diversity of phlD
+ bacteria was studied by amplified 16S rDNA restriction analysis and demonstrated eleven groups at 65% similarity level. Out
of these 42 phlD
+ antagonistic isolates, twenty exhibited significantly fair plant growth promoting activities like phosphate solubilization
(0.92–5.33%), 25 produced indole acetic acid (1.63–7.78 μg ml−1) and few strains show production of antifungal metabolites (HCN and siderophore). The screening of PGPR (phlD
+) for suppression of bacterial wilt disease in glass house conditions was showed ten isolated phlD
+ bacteria were able to suppress infection of bacterial wilt disease in tomato plant (var. Arka vikas) in the presence R. solanacearum. The PGPR (phlD
+) isolates s188, s215 and s288 was observed to be effective plant growth promoter as it shows highest dry weight per plant
(3.86, 3.85 and 3.69 g plant−1 respectively). The complete absence of wilt disease symptoms in tomato crop plants was observed by these treatments compared
to negative control. Therefore inoculation of tomato plant with phlD
+ isolate s188 and other similar biocontrol agents may prove to be a positive strategy for checking wilt disease and thus improving
plant vigor. 相似文献
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Paula Barrionuevo M. Victoria Delpino Roberto G. Pozner Lis N. Velásquez Juliana Cassataro Guillermo H. Giambartolomei 《Cellular microbiology》2013,15(4):487-502
Brucella abortus elicits a vigorous Th1 immune response which activates cytotoxic T lymphocytes. However, B. abortus persists in its hosts in the presence of CD8+ T cells, establishing a chronic infection. Here, we report that B. abortus infection of human monocytes/macrophages inhibited the IFN‐γ‐induced MHC‐I cell surface expression. This phenomenon was dependent on metabolically active viable bacteria. MHC‐I down‐modulation correlated with the development of diminished CD8+ cytotoxic T cell response as evidenced by the reduced expression of the activation marker CD107a on CD8+ T lymphocytes and a diminished percentage of IFN‐γ‐producing CD8+ T cells. Inhibition of MHC‐I expression was not due to changes in protein synthesis. Rather, we observed that upon B. abortus infection MHC‐I molecules were retained within the Golgi apparatus. Overall, these results describe a novel mechanism based on the intracellular sequestration of MHC‐I molecules whereby B. abortus would avoid CD8+ cytotoxic T cell responses, evading their immunological surveillance. 相似文献
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The perennial energy crop Miscanthus × giganteus is recognized for its extraordinary nitrogen‐use efficiency. While the remobilization of nitrogen (N) to the rhizome after the growth phase contributes to this efficiency, the plant‐associated microbiome might also contribute, as N‐fixing bacterial species had been isolated from this grass. Here, we studied established Miscanthus × giganteus plots in southern Germany that either received 80 kg N ha?1 a?1 or that were not N‐fertilized for 14 years. The bacterial communities of the bulk soil, rhizosphere, roots and rhizomes were analysed. Major differences were encountered between plant‐associated fractions. Nitrogen had little effect on soil communities. The roots and rhizomes showed less microbial diversity than soil fractions. In these compartments, Actinobacteria and N‐fixing symbiosis‐associated Proteobacteria depended on N. Intriguingly, N2‐fixing‐related bacterial families were enriched in the rhizomes in long‐term zero N plots, while denitrifier‐related families were depleted. These findings point to the rhizome as a potentially interesting plant organ for N fixation and demonstrate long‐term differences in the organ‐specific bacterial communities associated with different N supply, which are mainly shaped by the plant. 相似文献
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Layered Na‐Ion Cathodes with Outstanding Performance Resulting from the Synergetic Effect of Mixed P‐ and O‐Type Phases
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Herein, the synthesis of new quaternary layered Na‐based oxides of the type NaxMnyNizFe0.1Mg0.1O2 (0.67≤ x ≤ 1.0; 0.5≤ y ≤ 0.7; 0.1≤ z ≤ 0.3) is described. The synthesis can be tuned to obtain P2‐ and O3‐type as well as mixed P‐/O‐type phases as demonstrated by structural, morphological, and electrochemical properties characterization. Although all materials show good electrochemical performance, the simultaneous presence of the P‐ and O‐type phases is found to have a synergetic effect resulting in outstanding performance of the mixed phase material as a sodium‐ion cathode. The mixed P3/P2/O3‐type material, having an average elemental composition of Na0.76Mn0.5Ni0.3Fe0.1Mg0.1O2, overcomes the specific drawbacks associated with the P2‐ and O3‐type materials, allowing the outstanding electrochemical performance. In detail, the mixed phase material is able to deliver specific discharge capacities of up to 155 mAh g?1 (18 mA g?1) in the potential range of 2.0–4.3 V. In the narrower potential range of 2.5–4.3 V the material exhibits high average discharge potential (3.4 V versus Na/Na+), exceptional average coulombic efficiencies (>99.9%), and extraordinary capacity retention (90.2% after 601 cycles). The unexplored class of P‐/O‐type mixed phases introduces new perspectives for the development of layered positive electrode materials and powerful Na‐ion batteries. 相似文献