共查询到20条相似文献,搜索用时 15 毫秒
1.
The applicability of emission of the N 3Λσ triplet states of molecular hydrogen for spectral diagnostics of the positive column of a dc glow discharge in hydrogen at translational gas temperatures of 360–600 K, specific absorbed powers of 0.8–4.25 W/cm, gas pressures of p = 0.3–15.0 Torr, reduced fields of E/N = 30–130 Td, and electron densities of n e = 4.0 × 109–6.5 × 1010 cm–3 is analyzed by using an advanced level-based semi-empirical collisional?radiative model. It is found that secondary processes make the main contribution to the population and decay of the N 3Λσ = a 3Σ+ g , c 3Π u , g 3Σ+ g , h 3Σ+ g , and i 3Π g triplet states. The dipole-allowed transitions e 3Σ+ g → a 3Σ+ g , f 3Σ+ g → a 3Σ+ g , g 3Σ+ g and k 3Π u → a 3Σ+ g can be used for spectral diagnostics of a dc discharge within a simplified coronal model. 相似文献
2.
A controversy of long standing in membrane electrophysio-logy is whether the sodium ion current (INa) and potassium ion current (IK) pass through the membrane in separate channels, or through a single set of channels which conduct first INa and then IK. In support of the latter hypothesis it has been noted that the sodium conductance (gNa) decline, called inactivation, proceeds with about the same time course as the potassium conductance (gK) increase. This could mean that Na+ selective channels are being converted into K+ selective channels. The hypothesis is especially interesting because of the possibility that the carrier postulated in active transport is convertible from Na+ to K+ selectivity1. An explicit statement of the single channel hypothesis and the means for disproving it were given by Mullins2. Because a single channel could not simultaneously conduct INa and IK, disproof requires that membrane conductance (gm) be made somehow to exceed the maximum value of gNa or gK. We report here that inactivation of gNa can be destroyed fairly selectively by the action from inside the axon of the unspecific proteolytic enzymes of pronase. In many cases gm after pronase treatment is greater than maximum gK before treatment, making untenable the single channel hypothesis. 相似文献
3.
A. Moussous C. Paris M. Khelifi-Slaoui M. Bekhouche D. Zaoui S. M. Rosloski A. Makhzoum S. Desobry L. Khelifi 《In vitro cellular & developmental biology. Plant》2018,54(1):117-126
Transgenic hairy roots of Datura spp., established using strain A4 of Agrobacterium rhizogenes, are genetically stable and produce high levels of tropane alkaloids. To increase biomass and tropane alkaloid content of this plant tissue, four Pseudomonas strains, Pseudomonas fluorescens P64, P66, C7R12, and Pseudomonas putida PP01 were assayed as biotic elicitors on transgenic hairy roots of Datura stramonium, Datura tatula, and Datura innoxia. Alkaloids were extracted from dried biomass, and hyoscyamine and scopolamine were quantified using liquid chromatography-tandem mass spectrometry analysis. D. stramonium and D. innoxia biomass production was stimulated by all Pseudomonas spp. strains after a 5-d treatment. All strains of P. fluorescens increased hyoscyamine yields compared to untreated cultures after both 5 and 10 d of treatment. Hyoscyamine yields were highest in D. tatula cultures exposed to a 5-d treatment with C7R12 (16.633 + 0.456 mg g?1 dry weight, a 431% increase) although the highest yield increases compared to the control were observed in D. stramonium cultures exposed to strains P64 (511% increase) and C7R12 (583% increase) for 10 d. D. innoxia showed the highest scopolamine yields after elicitation with P. fluorescens strains P64 for 5 d (0.653 + 0.021 mg g?1 dry weight, a 265% increase) and P66 for 5 and 10 d (5 d, 0.754 + 0.0.031 mg g?1 dry weight, a 321% increase; 10 d 0.634 + 0.046 mg g?1 dry weight, a 277% increase). These results show that the Pseudomonas strains studied here can positively and significantly affect biomass and the yields of hyoscyamine and scopolamine from transgenic roots of the three Datura species. 相似文献
4.
The parameters of the electrode region of an electrode microwave discharge in nitrogen are studied by emission spectroscopy. The radial and axial distributions of the intensities of the bands of the second (N2(C 3Π u → B 3Π g )) and first (N2(B 3Π g → A 3Σ u + )) positive systems of molecular nitrogen and the first negative system of nitrogen ions (N 2 + (B 2Σ u + → X 2Σ g + )), the radial profiles of the electric field E and the electron density N e , and the absolute populations of the vibrational levels v C = 0–4 of the C 3Π u excited state of N2 and the vibrational level v Bi = 0 of the B 2Σ u + excited state of a molecular nitrogen ion are determined. The population temperature of the first vibrational level T V of the ground electronic state X 1Σ g + of N2 and the excitation temperature T C of the C 3Π u state in the electrode region of the discharge are measured. The radius of the spherical region and the spatially integrated plasma emission spectra are studied as functions of the incident microwave power and gas pressure. A method for determining the electron density and the microwave field strength from the plasma emission characteristics is described in detail. 相似文献
5.
Nitrogen (N) is the key factor limiting photosynthetic processes and crop yield. Little is known about the response of leaf gas exchange of spring triticale (Triticosecale Wittm.) to N supply. The effect of N fertilizers on different gas exchange variables, i.e., photosynthetic rate (A), transpiration rate (E), stomatal conductance (g s), instantaneous water use efficiency (WUE) and maximum quantum yield of photosystem II (PSII) (F v/F m), chlorophyll index (SPAD, soil–plant analysis development), and the relationship of these variables with yield were studied in spring triticale grown under field conditions. Six treatments of N—0, 90, 180, 90 + 30, 90 + 30 + 30 kg ha?1 (applied as ammonium nitrate, AN) and one treatment of N 90 + 30 + 30 kg ha?1 (applied as urea ammonium nitrate solution, UAN) were compared. The analysis of variance showed that throughout the triticale growing season, N fertilization had significant effects on A, WUE, g s and SPAD. On average, N fertilizer application increased A values by 14–70%. E and F v/F m values were not influenced by N fertilization levels. The effect of growth stage and year on gas exchange variables and F v/F m and SPAD was found to be significant. At different growth stages, A values varied and maximum ones were reached at BBCH 31–33 (decimal code system of growth stages) and BBCH 59. With aging, values of A decreased independently of N fertilization level. The gas exchange variables were equally affected by both fertilizer forms. The interplay among grain yield, leaf gas exchange variables, F v/F m and SPAD of spring triticale was estimated. The statistical analysis showed that grain yield positively and significantly correlated with A and SPAD values throughout the growing season. 相似文献
6.
Devinder Sandhu Manju V. Pudussery Rakesh Kaundal Donald L. Suarez Amita Kaundal Rajandeep S. Sekhon 《Functional & integrative genomics》2018,18(2):141-153
One important mechanism plants use to cope with salinity is keeping the cytosolic Na+ concentration low by sequestering Na+ in vacuoles, a process facilitated by Na+/H+ exchangers (NHX). There are eight NHX genes (NHX1 through NHX8) identified and characterized in Arabidopsis thaliana. Bioinformatics analyses of the known Arabidopsis genes enabled us to identify six Medicago truncatula NHX genes (MtNHX1, MtNHX2, MtNHX3, MtNHX4, MtNHX6, and MtNHX7). Twelve transmembrane domains and an amiloride binding site were conserved in five out of six MtNHX proteins. Phylogenetic analysis involving A. thaliana, Glycine max, Phaseolus vulgaris, and M. truncatula revealed that each individual MtNHX class (class I: MtNHX1 through 4; class II: MtNHX6; class III: MtNHX7) falls under a separate clade. In a salinity-stress experiment, M. truncatula exhibited ~?20% reduction in biomass. In the salinity treatment, sodium contents increased by 178 and 75% in leaves and roots, respectively, and Cl? contents increased by 152 and 162%, respectively. Na+ exclusion may be responsible for the relatively smaller increase in Na+ concentration in roots under salt stress as compared to Cl?. Decline in tissue K+ concentration under salinity was not surprising as some antiporters play an important role in transporting both Na+ and K + . MtNHX1, MtNHX6, and MtNHX7 display high expression in roots and leaves. MtNHX3, MtNHX6, and MtNHX7 were induced in roots under salinity stress. Expression analysis results indicate that sequestering Na+ into vacuoles may not be the principal component trait of the salt tolerance mechanism in M. truncatula and other component traits may be pivotal. 相似文献
7.
O. S. Zhdanova V. S. Kuznetsov V. A. Panarin V. S. Skakun E. A. Sosnin V. F. Tarasenko 《Plasma Physics Reports》2018,44(1):153-156
In a single-barrier discharge with voltage sharpening and low gas consumption (up to 1 L/min), plane atmospheric pressure plasma jets with a width of up to 3 cm and length of up to 4 cm in air are formed in the slit geometry of the discharge zone. The energy, temperature, and spectral characteristics of the obtained jets have been measured. The radiation spectrum contains intense maxima corresponding to vibrational transitions of the second positive system of molecular nitrogen N2 (C3Π u → B3Π g ) and comparatively weak transition lines of the first positive system of the N 2 + ion (B2Σ u + → X2Σ g ). By an example of inactivation of the Staphylococcus aureus culture (strain ATCC 209), it is shown that plasma is a source of chemically active particles providing the inactivation of microorganisms. 相似文献
8.
A. V. Kuzyomenskii 《Cytology and Genetics》2007,41(5):268-275
Results from works involving the study of hetero-and homozygous interaction of the keeping quality genes alc, nor, and rin in tomato plants are presented. It is shown that cumulative polymery leading to the formation of a new “long ripening” phenotype is observed in the double heterozygotes alc/alc +//nor/nor +, nor/nor +//rin/rin +, and alc/alc +//rin/rin +. Strong inhibition of processes of ripeness and synthesis of carotenoids occurs with nonallelic interaction in the double homozygotes alc/alc//rin/rin, nor/nor//rin/rin, and alc/alc//nor/nor. This promotes the formation of a new “non-ripening” phenotype with the absence of visual signs of ripeness, i.e., a whitish-green coloring of the fruit. 相似文献
9.
T. M. Rogoza O. V. Viktorovskaya S. A. Rodionova M. S. Ivanov K. V. Volkov L. N. Mironova 《Molecular Biology》2009,43(3):360-366
The prion-like determinant [ISP +] manifests itself as an antisuppressor of certain sup35 mutations. To establish that [ISP +] is indeed a new yeast prion, it is necessary to identify the gene that codes for the protein whose prion form is [ISP +]. Analysis of the transformants obtained by transformation of an [ISP +] strain with an insertion gene library revealed three genes controlling the [ISP +] maintenance: UPF1, UPF2, and SFP1. SFP1 codes for a potentially prionogenic protein, which is enriched in Asn and Gln residues, and is thereby the most likely candidate for the [ISP +] structural gene. UPF1 and UPF2 code for components of nonsense-mediated mRNA decay. The [ISP +] elimination caused by UPF1 and UPF2 inactivation was reversible, and Upf1p and Upf2p were not functionally related to phosphatase Ppz1p, which influences the [ISP +] manifestation. Possible mechanisms sustaining the influence of UPF1 and UPF2 on [ISP +] maintenance are discussed. 相似文献
10.
Hui Li Wei Liu Qing-Song Yang Jing Lin You-Hong Chang 《Plant Molecular Biology Reporter》2018,36(3):439-450
11.
12.
Muhammad A. Asif Rhiannon K. Schilling Joanne Tilbrook Chris Brien Kate Dowling Huwaida Rabie Laura Short Christine Trittermann Alexandre Garcia Edward G. Barrett-Lennard Bettina Berger Diane E. Mather Matthew Gilliham Delphine Fleury Mark Tester Stuart J. Roy Allison S. Pearson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2018,131(10):2179-2196
Key message
Novel QTL for salinity tolerance traits have been detected using non-destructive and destructive phenotyping in bread wheat and were shown to be linked to improvements in yield in saline fields.Abstract
Soil salinity is a major limitation to cereal production. Breeding new salt-tolerant cultivars has the potential to improve cereal crop yields. In this study, a doubled haploid bread wheat mapping population, derived from the bi-parental cross of Excalibur?×?Kukri, was grown in a glasshouse under control and salinity treatments and evaluated using high-throughput non-destructive imaging technology. Quantitative trait locus (QTL) analysis of this population detected multiple QTL under salt and control treatments. Of these, six QTL were detected in the salt treatment including one for maintenance of shoot growth under salinity (QG(1–5).asl-7A), one for leaf Na+ exclusion (QNa.asl-7A) and four for leaf K+ accumulation (QK.asl-2B.1, QK.asl-2B.2, QK.asl-5A and QK:Na.asl-6A). The beneficial allele for QG(1–5).asl-7A (the maintenance of shoot growth under salinity) was present in six out of 44 mainly Australian bread and durum wheat cultivars. The effect of each QTL allele on grain yield was tested in a range of salinity concentrations at three field sites across 2 years. In six out of nine field trials with different levels of salinity stress, lines with alleles for Na+ exclusion and/or K+ maintenance at three QTL (QNa.asl-7A, QK.asl-2B.2 and QK:Na.asl-6A) excluded more Na+ or accumulated more K+ compared to lines without these alleles. Importantly, the QK.asl-2B.2 allele for higher K+ accumulation was found to be associated with higher grain yield at all field sites. Several alleles at other QTL were associated with higher grain yields at selected field sites.13.
Check of Gene Number during the Process of rDNA Magnification 总被引:1,自引:0,他引:1
THE multiple sequences of rDNA (DNA complementary to ribosomal RNA) of the Drosophila genome are localized at the bobbed locus, located in the X chromosome, position 66 and in the short arm of the Y chromosome1,2. Wild bobbed (bb+) is that locus which, without a partner, gives rise to a normal phenotype. That locus which in similar conditions is incapable of giving rise to a normal phenotype is called a bobbed mutation (bb) and contains fewer genes for rRNA. The number of genes for rRNA in different individuals can vary considerably. One mechanism for rDNA variation is unequal crossing over3. Another mechanism, described by Tartof4, becomes apparent when individual flies, carrying only one bobbed locus, are constructed and only if such a locus is on the X chromosome; that is, if one constructs Xbb+/O males (and also Xbb/O males) or Xbb+/XNO- females. Such individuals show a higher rDNA content than expected from the analysis of the same locus in Xbb+/Xbb+ females or in Xbb+/Ybb+ males. The increase of rDNA in this case is not inheritable4. 相似文献
14.
S. M. Gupta A. Agarwal B. Dev K. Kumar O. Prakash M. C. Arya M. Nasim 《Photosynthetica》2016,54(1):138-142
Photosynthetic parameters including net photosynthetic rate (PN), transpiration rate (E), water-use efficiency (WUE), and stomatal conductance (gs) were studied in indoor C3 plants Philodendron domesticum (Pd), Dracaena fragans (Df), Peperomia obtussifolia (Po), Chlorophytum comosum (Cc), and in a CAM plant, Sansevieria trifasciata (St), exposed to various low temperatures (0, 5, 10, 15, 20, and 25°C). All studied plants survived up to 0°C, but only St and Cc endured, while other plants wilted, when the temperature increased back to room temperature (25°C). The PN declined rapidly with the decrease of temperature in all studied plants. St showed the maximum PN of 11.9 μmol m?2 s?1 at 25°C followed by Cc, Po, Pd, and Df. E also followed a trend almost similar to that of PN. St showed minimum E (0.1 mmol m?2 s?1) as compared to other studied C3 plants at 25°C. The E decreased up to ≈4-fold at 5 and 0°C. Furthermore, a considerable decline in WUE was observed under cold stress in all C3 plants, while St showed maximum WUE. Similarly, the gs also declined gradually with the decrease in the temperature in all plants. Among C3 plants, Pd and Po showed the maximum gs of 0.07 mol m?2 s?1 at 25°C followed by Df and Cc. However, St showed the minimum gs that further decreased up to ~4-fold at 0°C. In addition, the content of photosynthetic pigments [chlorophyll a, b, (a+b), and carotenoids] was varying in all studied plants at 0°C. Our findings clearly indicated the best photosynthetic potential of St compared to other studied plants. This species might be recommended for improving air quality in high-altitude closed environments. 相似文献
15.
The present study introduced and evaluated modification of E. coli BL21 (DE3) to improve its biosorption capacity by the transfer of the Corynebacterium glutamicum metallothionein gene (C.gMT). The C.gMT sequence was extracted and cloned in pET28a vector and the ligation product was transferred into E. coli BL21 (DE3). It has been also submitted to the GenBank database (accession number KJ638906.1). The performance of the recombinant bacterium was evaluated at different metal ions concentrations, contact times, pH values, and co-ions. The results show that recombinant BL21 (DE3) was able to uptake Pb+2, and Zn+2 at greater percentages than could BL21 (DE3). The optimum pH for the removal of each heavy metal was different. As contact time increased, Pb+2 and Zn+2 biosorption by the recombinant bacterium increased, while the biosorption of Cd+2 remained at a nearly steady rate for contact times of more than 1 h. Increasing the concentrations of Pb+2 and Zn+2 in solution increased biosorption of these metals by the recombinant BL21 (DE3) over that of Cd+2. It could be hypothesized that Pb+2 and Zn+2 removal by C.gMT-engineered BL21 (DE3) occurred mainly via intracellular biosorption (absorption) and that Cd+2 was mainly taken up through cell surface biosorption (adsorption). 相似文献
16.
17.
Xiaohui Liu Shenguan Cai Gang Wang Feifei Wang Fabao Dong Michelle Mak Paul Holford Jing Ji Anya Salih Meixue Zhou Sergey Shabala Zhong-Hua Chen 《Plant Growth Regulation》2017,82(2):333-351
While the role of the vacuolar NHX Na+/H+ exchangers in plant salt tolerance has been demonstrated on numerous occasions, their control over cytosolic ionic relations has never been functionally analysed in the context of subcellular Na+ and K+ homeostasis. In this work, PutNHX1 and SeNHX1 were cloned from halophytes Puccinellia tenuiflora and Salicornia europaea and transiently expressed in Arabidopsis wild type Col-0 and the nhx1 mutant. Phylogentic analysis, topological prediction, analysis of evolutionary conservation, the topology structure and analysis of hydrophobic or polar regions of PutNHX1 and SeNHX1 indicated that they are unique tonoplast Na+/H+ antiporters with characteristics for salt tolerance. As a part of the functional assessment, cytosolic and vacuolar Na+ and K+ in different root tissues and ion fluxes from root mature zone of Col-0, nhx1 and their transgenic lines were measured. Transgenic lines sequestered large quantity of Na+ into root cell vacuoles and also promoted high cytosolic and vacuolar K+ accumulation. Expression of PutNHX1 and SeNHX1 led to significant transient root Na+ uptake in the four transgenic lines upon recovery from salt treatment. In contrast, the nhx1 mutant maintained a prolonged Na+ efflux and the nhx1:PutNHX1 and nhx1:SeNHX1 lines started to actively pump Na+ out of the cell. Overall, our findings suggest that PutNHX1 and SeNHX1 improve Na+ sequestration in the vacuole and K+ retention in the cytosol and vacuole of root cells of Arabidopsis, and that they interact with other regulatory mechanisms to provide a highly orchestrated regulation of ionic relations among intracellular cell compartments. 相似文献
18.