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81.
Tonic activation of NMDA receptors by ambient glutamate enhances excitability of neurons 总被引:14,自引:0,他引:14
Voltage clamp recordings and noise analysis from pyramidal cells in hippocampal slices indicate that N-methyl-D-aspartate (NMDA) receptors are tonically active. On the basis of the known concentration of glutamate in the extracellular fluid, this tonic action is likely caused by the ambient glutamate level. NMDA receptors are voltage-sensitive, thus background activation of these receptors imparts a regenerative electrical property to pyramidal cells, which facilitates the coupling between dendritic excitatory synaptic input and somatic action potential discharge in these neurons. 相似文献
82.
83.
Glutathione (GSH) abundantly presents in plant and affects plants growth and development. To justify if GSH affects copper (Cu)-induced corn production, photosynthesis (Pn) rate, and photosynthetically active radiation (PAR), chlorophyll (Chl) content and Chl fluorescence, relative water content (RWC) and yields were evaluated. Different Cu concentrations (0, 0.2, 1.5 and 3.0 ppm of Zn) with or without 100 µm of N-acetyl cysteine (NAC) were arranged as completely randomize design with 5 replications. Results showed that both NAC and Cu affected plant height and leaf numbers. Copper reduced Pn rate, and PAR and increased RWC but no effect was observed on Chl content and Chl fluorescence in leaves. On the other hand, NAC application increased Pn, PAR, Chl parameters regardless of Cu treatment. In the presence of 1.5 ppm of Cu, corn plants showed improve yield and cob length irrespective to NAC treatment. Taken together, this study suggests that NAC might improve some physiological functions in plants to enhance Cu-induced corn production. 相似文献
84.
Bendall SC Simonds EF Qiu P Amir el-AD Krutzik PO Finck R Bruggner RV Melamed R Trejo A Ornatsky OI Balderas RS Plevritis SK Sachs K Pe'er D Tanner SD Nolan GP 《Science (New York, N.Y.)》2011,332(6030):687-696
Flow cytometry is an essential tool for dissecting the functional complexity of hematopoiesis. We used single-cell "mass cytometry" to examine healthy human bone marrow, measuring 34 parameters simultaneously in single cells (binding of 31 antibodies, viability, DNA content, and relative cell size). The signaling behavior of cell subsets spanning a defined hematopoietic hierarchy was monitored with 18 simultaneous markers of functional signaling states perturbed by a set of ex vivo stimuli and inhibitors. The data set allowed for an algorithmically driven assembly of related cell types defined by surface antigen expression, providing a superimposable map of cell signaling responses in combination with drug inhibition. Visualized in this manner, the analysis revealed previously unappreciated instances of both precise signaling responses that were bounded within conventionally defined cell subsets and more continuous phosphorylation responses that crossed cell population boundaries in unexpected manners yet tracked closely with cellular phenotype. Collectively, such single-cell analyses provide system-wide views of immune signaling in healthy human hematopoiesis, against which drug action and disease can be compared for mechanistic studies and pharmacologic intervention. 相似文献
85.
Avinoam O Fridman K Valansi C Abutbul I Zeev-Ben-Mordehai T Maurer UE Sapir A Danino D Grünewald K White JM Podbilewicz B 《Science (New York, N.Y.)》2011,332(6029):589-592
Caenorhabditis elegans proteins AFF-1 and EFF-1 [C. elegans fusion family (CeFF) proteins] are essential for developmental cell-to-cell fusion and can merge insect cells. To study the structure and function of AFF-1, we constructed vesicular stomatitis virus (VSV) displaying AFF-1 on the viral envelope, substituting the native fusogen VSV glycoprotein. Electron microscopy and tomography revealed that AFF-1 formed distinct supercomplexes resembling pentameric and hexameric "flowers" on pseudoviruses. Viruses carrying AFF-1 infected mammalian cells only when CeFFs were on the target cell surface. Furthermore, we identified fusion family (FF) proteins within and beyond nematodes, and divergent members from the human parasitic nematode Trichinella spiralis and the chordate Branchiostoma floridae could also fuse mammalian cells. Thus, FF proteins are part of an ancient family of cellular fusogens that can promote fusion when expressed on a viral particle. 相似文献
86.
87.
Anderson WA Amasino RM Ares M Banerjee U Bartel B Corces VG Drennan CL Elgin SC Epstein IR Fanning E Guillette LJ Handelsman J Hatfull GF Hoy RR Kelley D Leinwand LA Losick R Lu Y Lynn DG Neuhauser C O'Dowd DK Olivera T Pevzner P Richards-Kortum RR Rine J Sah RL Strobel SA Walker GC Walt DR Warner IM Wessler S Willard HF Zare RN 《Science (New York, N.Y.)》2011,334(6057):760-761
88.
Min‐Jung GU Md. Jahangir ALAM Seon‐Ho KIM Che‐Ok JEON Moon‐Baek CHANG Young‐Kyoon OH Sang‐Cheol LEE Sang‐Suk LEE 《Animal Science Journal》2011,82(5):663-672
Molecular diversity of methanogens in the rumen of Korean black goats was investigated with 16S rRNA gene clone libraries using methanogen‐specific primers. The libraries were composed of rumen fluid‐associated methanogens (FAM) and rumen particle‐associated methanogens (PAM) from rumen‐fistulated Korean black goats. Among the 141 clones of the FAM library, the sequences were mostly related to two phyla, the Methanobacteriaceae family (77.3%) and the Thermoplasmatales family (22.7%); and among the 68 clones of the PAM library, sequences were also mainly clustered in the two phyla, the Thermoplasmatales family (63.24%) and the Methanobacteriaceae family (35.29%). Most of the sequenced clones in the two libraries were closely related to uncultured methanogenic archaeon. Quantitative real‐time PCR revealed that PAM (8.97 log 10) had significantly higher (P < 0.01) density of methanogens by the methanogenic 16S rRNA gene copies than FAM (7.57 log 10). The two clone libraries also showed difference in Shannon index (FAM library 1.70 and PAM library 1.59) and Chao 1 estimator (FAM library 18 and PAM library 17 operational taxonomic units). Apparent differences found in the microbial community from the two 16S rRNA gene libraries could be a result of such factors as the chemical and physical nature of the target material surface, types or component of diets, the interaction between the methanogens and other microbes, and age of the experimental goats. 相似文献
89.
Syed Jawad Ahmad Shah Shaukat Hussain Musharaf Ahmad Farhatullah Iftikhar Ali Muhammad Ibrahim 《Journal of General Plant Pathology》2011,77(3):174-177
Fifty wheat varieties along with Jupateco-73 and Morocco were studied for the expression of leaf tip necrosis (LTN), a trait
linked with the durable rust resistance gene pair Lr34/Yr18. LTN was frequent (i.e., ≥6) in nine replications of a field experiment over 3 years in 17 genotypes, and the varieties were
considered positive for LTN. In molecular analyses of these varieties, having relative severity values up to 78 for yellow
rust and 45 for leaf rust, the 150-bp Lr34/Yr18-linked allele was consistently amplified. Expression of LTN in six of nine replications is an appropriate threshold for predicting
the presence of Lr34/Yr18 gene pair, and genotypes can be selected using this trait. 相似文献
90.
Mohammad Shafi Jehan Bakht Mohammad Tariq Jan Zahir Shah 《Soil & Tillage Research》2007,94(2):520-529
This paper presents the results of irrigated rotation experiment, conducted in the North West Frontier Province (NWFP), Pakistan, during 1999–2002 to evaluate effects of residues retention, fertilizer N and legumes in crop rotation on yield of maize (Zea mays L.) and soil organic fertility. Chickpea (Cicer arietinum L) and wheat (Triticum aestivum L) were grown in the winters and mungbean (Vigna radiata) and maize in the summers. Immediately after grain harvest, above-ground residues of all crops were either completely removed (−residue), or spread across the plots and incorporated by chisel plough by disc harrow and rotavator (+residue). Fertlizer N rates were nil or 120 kg ha−1 for wheat and nil or 160 kg ha−1 for maize. Our results indicated that post-harvest incorporation of crop residues significantly (p < 0.05) increased the grain and stover yields of maize during both 2000 and 2001. On average, grain yield was increased by 23.7% and stover yield by 26.7% due to residue incorporation. Residue retention also enhanced N uptake by 28.3% in grain and 45.1% in stover of maize. The soil N fertility was improved by 29.2% due to residue retention. The maize grain and stover yields also responded significantly to the previous legume (chickpea) compared with the previous cereal (wheat) treatment. The legume treatment boosted grain yield of maize by 112% and stover yield by 133% with 64.4% increase in soil N fertility. Similarly, fertilizer N applied to previous wheat showed considerable carry over effect on grain (8.9%) and stover (40.7%) yields of the following maize. Application of fertilizer N to current maize substantially increased grain yield of maize by 110%, stover yield by 167% and soil N fertility by 9.8% over the nil N fertilizer treatment. We concluded from these experiments that returning of crop residues, application of fertilizer N and involvement of legumes in crop rotation greatly improves the N economy of the cropping systems and enhances crop productivity through additional N and other benefits in low N soils. The farmers who traditionally remove residues for fodder and fuel will require demonstration of the relative benefits of residues return to soil for sustainable crop productivity. 相似文献