Investigation of Na+ and K+ Transport in Halophytes: Functional Analysis of the HmHKT2;1 Transporter from Hordeum maritimum and Expression under Saline Conditions

2019 ◽  
Vol 60 (11) ◽  
pp. 2423-2435 ◽  
Author(s):  
Dorsaf Hmidi ◽  
Dorsaf Messedi ◽  
Claire Corratg�-Faillie ◽  
Th�o Marhuenda ◽  
C�cile Fizames ◽  
...  
Keyword(s):  
Absorption Efficiency ◽  
Extracellular Loop ◽  
Transmembrane Segment ◽  
Transport Pathway ◽  
Reverse Transcription Pcr ◽  
Encoding Gene ◽  
K Transport ◽  
Different Levels ◽  
Adaptation To Salinity

Abstract Control of K+ and Na+ transport plays a central role in plant adaptation to salinity. In the halophyte Hordeum maritimum, we have characterized a transporter gene, named HmHKT2;1, whose homolog HvHKT2;1 in cultivated barley, Hordeum vulgare, was known to give rise to increased salt tolerance when overexpressed. The encoded protein is strictly identical in two H. maritimum ecotypes, from two biotopes (Tunisian sebkhas) affected by different levels of salinity. These two ecotypes were found to display distinctive responses to salt stress in terms of biomass production, Na+ contents, K+ contents and K+ absorption efficiency. Electrophysiological analysis of HmHKT2;1 in Xenopus oocytes revealed distinctive properties when compared with HvHKT2;1 and other transporters from the same group, especially a much higher affinity for both Na+ and K+, and an Na+–K+ symporter behavior in a very broad range of Na+ and K+ concentrations, due to reduced K+ blockage of the transport pathway. Domain swapping experiments identified the region including the fifth transmembrane segment and the adjacent extracellular loop as playing a major role in the determination of the affinity for Na+ and the level of K+ blockage in these HKT2;1 transporters. The analysis (quantitative reverse transcription-PCR; qRT-PCR) of HmHKT2;1 expression in the two ecotypes submitted to saline conditions revealed that the levels of HmHKT2;1 transcripts were maintained constant in the most salt-tolerant ecotype whereas they decreased in the less tolerant one. Both the unique functional properties of HmHKT2;1 and the regulation of the expression of the encoding gene could contribute to H. maritimum adaptation to salinity.

On-the-Fly Determination of Active Region Centers in Adaptive-Partitioning QM/MM

2020 ◽  
Author(s):  
Zenghui Yang
Keyword(s):  
Quantum Mechanics ◽  
Active Region ◽  
Molecular Mechanics ◽  
Active Regions ◽  
Available Energy ◽  
Adaptive Partitioning ◽  
Different Levels

Quantum mechanics/molecular mechanics (QM/MM) methods partition the system into active and environmental regions and treat them with different levels of theory, achieving accuracy and efficiency at the same time. Adaptive-partitioning (AP) QM/MM methods allow on-the-fly changes to the QM/MM partitioning of the system. Many of the available energy-based AP-QM/MM methods partition the system according to distances to pre-chosen centers of active regions. For such AP-QM/MM methods, I develop an adaptive-center (AC) method that allows on-the-fly determination of the centers of active regions according to general geometrical or potential-related criteria, extending the range of application of energy-based AP-QM/MM methods to systems where active regions may occur or vanish during the simulation.

scholarly journals Circulating bioactive sclerostin levels in an Austrian population-based cohort

2021 ◽  
Author(s):  
Katharina Kerschan-Schindl ◽  
Ursula Föger-Samwald ◽  
Andreas Gleiss ◽  
Stefan Kudlacek ◽  
Jacqueline Wallwitz ◽  
...  
Keyword(s):  
Serum Levels ◽  
Population Based ◽  
Negative Regulator ◽  
Total Serum ◽  
Mineral Density ◽  
Cross Sectional ◽  
Robust Parameter ◽  
Austrian Population ◽  
Different Levels

Summary Background Circulating serum sclerostin levels are supposed to give a good estimation of the levels of this negative regulator of bone mass within bone. Most studies evaluating total serum sclerostin found different levels in males compared to females and in older compared to younger subjects. Besides an ELISA detecting total sclerostin an ELISA determining bioactive sclerostin has been developed. The aim of this study was to investigate serum levels of bioactive sclerostin in an Austrian population-based cohort. Methods We conducted a cross-sectional observational study in 235 healthy subjects. Using the bioactive ELISA assay (Biomedica) bioactive sclerostin levels were evaluated. Results Serum levels of bioactive sclerostin were higher in men than in women (24%). The levels correlated positively with age (r = 0.47). A positive correlation could also be detected with body mass index and bone mineral density. Conclusion Using the ELISA detecting bioactive sclerostin our results are consistent with data in the literature obtained by different sclerostin assays. The determination of sclerostin concentrations in peripheral blood thus appears to be a robust parameter of bone metabolism.

scholarly journals Simultaneous determination of various platycosides in Four Platycodon grandiflorum cultivars by UPLC-QTOF/MS

2019 ◽  
Vol 62 (1) ◽  
Author(s):  
Dae Young Lee ◽  
Bo-Ram Choi ◽  
Jae Won Lee ◽  
Yurry Um ◽  
Dahye Yoon ◽  
...  
Keyword(s):  
Principal Component ◽  
Ultra Performance Liquid Chromatography ◽  
Platycodon Grandiflorum ◽  
Pentacyclic Triterpenoid ◽  
Flight Mass Spectrometry ◽  
Platycodi Radix ◽  
Isomeric Pairs ◽  
Different Levels

Abstract In Platycodi Radix (root of Platycodon grandiflorum), there are a number of platycosides that consist of a pentacyclic triterpenoid aglycone and two sugar moieties. Due to the pharmacological activities of platycosides, it is critical to assess their contents in PR, and develop an effective method to profile various platycosides is required. In this study, an analytical method based on ultra performance liquid chromatography coupled with quadrupole time-of-flight/mass spectrometry (UPLC-QTOF/MS) with an in-house library was developed and applied to profile various platycosides from four different Platycodi Radix cultivars. As a result, platycosides, including six isomeric pairs, were successfully analyzed in the PRs. In the principal component analysis, several platycosides were represented as main variables to differentiate the four Platycodi Radix cultivars. Their different levels of platycosides were also represented by relative quantification. Finally, this study indicated the proposed method based on the UPLC-QTOF/MS can be an effective tool for identifying the detail characterization of various platycosides in the Platycodi Radix.

Antimicrobial and antibiofilm activities of meropenem loaded-mesoporous silica nanoparticles against carbapenem-resistant Pseudomonas aeruginosa

2021 ◽  
pp. 088532822110038
Author(s):  
Mohammad Yousef Memar ◽  
Mina Yekani ◽  
Hadi Ghanbari ◽  
Edris Nabizadeh ◽  
Sepideh Zununi Vahed ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
Carbapenem Resistant ◽  
Toxicity In Vitro ◽  
Different Levels

The aims of the present study were the determination of antimicrobial and antibiofilm effects of meropenem-loaded mesoporous silica nanoparticles (MSNs) on carbapenem resistant Pseudomonas aeruginosa ( P. aeruginosa) and cytotoxicity properties in vitro. The meropenem-loaded MSNs had shown antibacterial and biofilm inhibitory activities on all isolates at different levels lower than MICs and BICs of meropenem. The viability of HC-04 cells treated with serial concentrations as MICs and BICs of meropenem-loaded MSNs was 92–100%. According to the obtained results, meropenem-loaded MSNs display the significant antibacterial and antibiofilm effects against carbapenem resistant and biofilm forming P. aeruginosa and low cell toxicity in vitro. Then, the prepared system can be an appropriate option for the delivery of carbapenem for further evaluation in vivo assays.

Institutions, Models of Capitalism and Inequality in Income Distribution: An Empirical Investigation

2017 ◽  
Vol 17 (3) ◽  
pp. 651-685 ◽  
Author(s):  
Gilberto Antonelli ◽  
Pinuccia P Calia ◽  
Giovanni Guidetti
Keyword(s):  
Income Inequality ◽  
Income Distribution ◽  
Empirical Investigation ◽  
Econometric Evidence ◽  
Definition Of ◽  
The Empirical Analysis ◽  
Statistical Indicators ◽  
Different Levels

Abstract The article analyses the role of institutions in the determination of income inequality in a sample of OECD countries. Basing on the seminal approach by Amable, the article discusses the theoretical definition of model of capitalism. The basic idea is that each model of capitalism is defined by the cobweb of complementary relationships established among different institutions. Using a set of statistical indicators of the operation of institutions in two different years, 1995 and 2010, the empirical analysis points out five models of capitalism and exhibits how their composition has changed in this lapse of 15 years. In the following sections of the article, we investigate the role played by the model of capitalism in the determination of income distribution, measured through a standard Gini index. After controlling for a set of variables, the econometric evidence shows that different models of capitalism present significantly different levels of income inequality.

K+ transport across the lamprey erythrocyte membrane: characteristics of a Ba(2+)- and amiloride-sensitive pathway

1991 ◽  
Vol 159 (1) ◽  
pp. 303-324 ◽  
Author(s):  
K. Kirk
Keyword(s):  
Membrane Potential ◽  
Erythrocyte Membrane ◽  
Inhibitory Effect ◽  
Extracellular Ph ◽  
Transport Pathway ◽  
Full Effect ◽  
River Lamprey ◽  
K Concentration ◽  
86Rb Influx ◽  
K Transport

The characteristics of K+ transport in erythrocytes from the river lamprey (Lampetra fluviatilis) were investigated using standard radioisotope flux techniques. The cells were shown to have a ouabain-sensitive transport pathway that carried 43K+ and 86Rb+ into the cell at similar rates. Most of the ouabain-resistant 43K+ and 86Rb+ influx was via a pathway that was insensitive to cotransport inhibitors and to the replacement of extracellular Cl- or Na+. This pathway showed a strong selectivity for 43K+ over 86Rb+. It was inhibited fully by Ba2+ (I50 approximately 2.8 mumol l-1), amiloride (I50 approximately 150 mumol l-1) and ethylisopropylamiloride (I50 approximately 3.3 mumol l-1) and less effectively by quinine and by the tetraethylammonium ion. Inhibition by Ba2+ took full effect within a few minutes whereas the full inhibitory effect of amiloride took more than 1 h to develop. Experiments with the membrane potential probe [14C]tetraphenylphosphonium ion gave results consistent with the lamprey erythrocyte membrane having a Ba(2+)-sensitive K+ conductance that was significantly greater than the membrane Na+ conductance and which gave rise to a marked dependence of the membrane potential on the extracellular K+ concentration. The rate constants for Ba(2+)-sensitive 43K+ and 86Rb+ influx decreased (proportionally) with increasing extracellular K+ concentration in a manner that was consistent with the transport being via a conductive pathway. The decrease was attributed to a depolarisation of the membrane (in response to the increasing extracellular K+ concentration) and a consequent decrease in the driving force for the conductive movement of 43K+ and 86Rb+ into the cells. Ba(2+)-sensitive 86Rb+ influx increased significantly with decreasing cell volume and with increasing intracellular pH (at a constant extracellular pH) but increased only slightly with increasing extracellular pH. The pathway operated normally in the complete absence of extracellular Ca2+ but its activity decreased in cells pretreated with ionomycin and EGTA; this suggests a role for intracellular Ca2+ in the operation of the pathway.

Determination of a Transmembrane Segment Using Cysteine-Scanning Mutants of Transposon Tn10-Encoded Metal−Tetracycline/H+Antiporter†

Biochemistry ◽  
1996 ◽  
Vol 35 (49) ◽  
pp. 15896-15899 ◽  
Author(s):  
Tomomi Kimura ◽  
Masayo Suzuki ◽  
Tetsuo Sawai ◽  
Akihito Yamaguchi
Keyword(s):  
Transmembrane Segment ◽  
Cysteine Scanning

scholarly journals Least limiting water range in Oxisols under different levels of machine traffic

2018 ◽  
Vol 8 (2) ◽  
pp. 337-346
Author(s):  
Karina De Vares Rossetti ◽  
José Frederico Centurion
Keyword(s):  
Bulk Density ◽  
Block Design ◽  
Corn Yield ◽  
Soil Penetration Resistance ◽  
Corn Crop ◽  
Randomized Block Design ◽  
Crop Development ◽  
Least Limiting Water Range ◽  
Different Levels

This work aimed, to evaluate the structural behavior of Oxisols based on the least limiting water range (LLWR) and establish relations with corn crop. The experiment was carried out in a randomized block design with five treatments and four replications. Soil samples collected at the layer of 0-0.20 m depth in a Haplustox (LVd) and an Eutrustox (LVef) were used. The compaction treatments consisted of T0= no additional compaction; T1 and T2= two and four passes with a 4 t tractor, respectively; T3 and T4 = two and four passes with a 10 t tractor, respectively. The range of LLWR variation in the LVd was the lowest one and varied from 0.01 to 0.04 m3 m-3, whereas in the LVef varied from 0.03 to 0.13 m3 m-3 for the critical soil penetration resistance (PRc) of 2 MPa. It was observed that critical bulk density (BDc) values were 1.76 and 1.40 Mg m-3 in the LVd and the LVef, respectively. The highest frequency of bulk density (BC ≥ BDc) occurred from the T1 to T4 (LVd) and from the T2 to T4, however, a reduction in corn yield was not observed. The determination of the LLWR was efficient and complementary for identifying more favorable or more impeditive conditions to compaction in the LVef for the corn crop development in relation to the LVd.

scholarly journals Analisis Berorientasi Objek Dalam Penentuan Tingkat Kreativitas Siswa Dengan Metode Fuzzy Mamdani

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Indra Kurniawan ◽  
Rahman Abdillah
Keyword(s):  
Qualitative Research ◽  
Problem Solving ◽  
Literature Review ◽  
Survey Method ◽  
Research Model ◽  
Different Levels

<em>Problem-solving skill requires the ability to think creatively in exploring various alternatives or solutions. Someone’s ability to think has different levels depending on works he produces. Therefore, it is necessary to carry out an analysis of the determination of student’s creativity level by employing a fuzzy mamdani method. The aim of this research is to know the process of determining the student’s creativity level by using a fuzzy mamdani method. The research applies a survey method with a qualitative research model in which the data are collected by observation, interview and literature review techniques</em>

scholarly journals Determination of Bovine Rotavirus G and P Serotypes in Italy by PCR

1999 ◽  
Vol 37 (12) ◽  
pp. 3879-3882 ◽  
Author(s):  
E. Falcone ◽  
M. Tarantino ◽  
L. Di Trani ◽  
P. Cordioli ◽  
A. Lavazza ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Clinical Signs ◽  
Specific Primers ◽  
Bovine Rotavirus ◽  
Reverse Transcription Pcr ◽  
Rotavirus Vaccines ◽  
Intestinal Contents ◽  
Group A

Determination of the G and P serotypes of group A bovine rotaviruses from 149 samples of feces or intestinal contents collected from calves showing clinical signs of neonatal diarrhea was performed by a nested reverse transcription-PCR typing assay. The G6 serotype was the most prevalent, accounting for viruses in 55.7% of the samples; viruses of the G10 and G8 serotypes were found in 34.9 and 4.7% of the samples, respectively. The virus in one sample (0.7%) was not classified due to concomitant infection with G6 and G8 strains, whereas viruses in six samples (4.0%) could not be characterized with any of the three G serotype-specific primers selected for the present study. When examined for their P-serotype specificities, viruses in 55 and 42.3% of the samples were characterized as P[11] and P[5], respectively, no P[1] serotype was identified, and viruses in 2.7% of the samples could not be classified due to multiple reactivity with both P[5]- and P[11]-specific primers. Various combinations of G and P serotypes were observed, the most frequent being G6,P[5] (38.3%), G10,P[11] (31.5%), and G6,P[11] (15.4%). The results of the present study, while contributing to a better understanding of the epidemiology of bovine rotaviruses in Italy, address the relevance of serotype specificity with regard to the constancy of the quality of bovine rotavirus vaccines under different field conditions.

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