Citric Acid in Rice Root Exudates Enhanced the Colonization and Plant Growth-Promoting Ability of Bacillus altitudinis LZP02.

Exploration of the underlying mechanisms of plant-microbe interactions is very important. In the present study, citric acid in the root exudates of rice significantly enhanced the colonization of Bacillus altitudinis LZP02 in the rhizosphere. According to the results of transcriptome and reverse transcription-quantitative PCR or analyses, citric acid increased the expression of several genes involved in bacterial chemotaxis and biofilm formation in B. altitudinis LZP02. In addition, citric acid also increased the expression of several genes associated with S-adenosylmethionine biosynthesis and metabolism. Interestingly, the secretion of citric acid by rice roots could be increased by inoculation with B. altitudinis LZP02. The result indicated that citric acid might be a vital signal in the interaction between rice and B. altitudinis LZP02. Further verification showed that citric acid enhanced the plant growth-promoting ability of B. altitudinis LZP02. IMPORTANCE In a previous study, the mechanism by which citric acid in rice root exudates enhanced the colonization of Bacillus altitudinis LZP02 was discovered. The present study verified that citric acid increased the recruitment and rice growth-promoting ability of B. altitudinis LZP02. These findings serve as an interesting case for explaining the underlying mechanisms of plant-microbe interactions. Henceforth, citric acid and B. altitudinis LZP02 could be exploited for the development of sustainable agronomy.

Hollow CoS/C Structures for High-Performance Li, Na, K Ion Batteries.

Alkali ion (Li, Na, and K) batteries as a new generation of energy storage devices are widely applied in portable electronic devices and large-scale energy storage equipment. The recent focus has been devoted to develop universal anodes for these alkali ion batteries with superior performance. Transition metal sulfides can accommodate alkaline ions with large radius to travel freely between layers due to its large interlayer spacing. Moreover, the composite with carbon material can further improve electrical conductivity of transition metal sulfides and reduce the electron transfer resistance, which is beneficial for the transport of alkali ions. Herein, we designed zeolitic imidazolate framework (ZIF)-derived hollow structures CoS/C for excellent alkali ion (Li, Na, and K) battery anodes. The porous carbon framework can improve the conductivity and effectively buffer the stress-induced structural damage. The ZIF-derived CoS/C anodes maintain a reversible capacity of 648.9, and 373.2, 224.8 mAh g-1 for Li, Na, and K ion batteries after 100 cycles, respectively. Its outstanding electrochemical performance is considered as a universal anode material for Li, Na, and K ion batteries.

An Improved Chemotaxis Assay for the Rapid Identification of Rhizobacterial Chemoattractants in Root Exudates.

Chemotaxis identification is very important for the research and application of rhizosphere growth-promoting bacteria. We established a straightforward method to quickly identify the chemoattractants that could induce the chemotactic movement of rhizosphere growth-promoting bacteria on sterile glass slides via simple steps. Bacteria solution (OD600 = 0.5) and sterile chemoattractant aqueous solution were added dropwise on the glass slide at an interval of 1 cm. An inoculating loop was used to connect the chemoattractant aqueous solution to the bacterial solution. The slide was kept at room temperature for 20 min on the clean bench. Finally, the chemoattractant aqueous solution was collected for bacterial counting and microscopic observation. In this study, through multiple comparisons of experimental results, the method overcame multiple shortcomings of traditional bacterial chemotaxis methods. The method reduced the error of plate counting and shortened the experimental cycle. For the identification of chemoattractant substances, this new method can save 2-3 days compared to the traditional method. Additionally, this method allows any researcher to systematically complete a bacterial chemotaxis experiment within 1-2 days. The protocol can be considered a valuable resource for understanding plant-microbe interactions.

Comparison of the gastric acid inhibition function among lansoprazole, pantoprazole, and their respective stereoisomers in healthy Chinese subjects
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OBJECTIVE: This study was conducted to evaluate the difference in acid inhibition function among lansoprazole (LPZ), pantoprazole (PPZ), and their respective stereoisomers following single and multiple intravenous doses in healthy Chinese subjects. MATERIALS AND METHODS: The dosage groups were set as follows: 30 mg single and multiple intravenous administrations of LPZ or R-LPZ, 40 mg single and multiple intravenous administrations of PPZ or S-PPZ. Subjects received an intravenous infusion of LPZ, R-LPZ, PPZ, or S-PPZ injection in sterile saline solution (100 mL/h, 60 minutes), respectively. The intragastric pH was sampled every second for 24 hours at baseline and for 24 hours after drug administration. The baseline-adjusted pharmacodynamic (PD) parameters include ΔMean (pH), ΔMedian (pH), ΔTpH≥3 (%), ΔTpH≥4 (%), ΔTpH≥6 (%), and ΔAUECph-tτ1-τ2. The PD parameters were evaluated in different time intervals (0 - 24 hours, 0 - 4 hours and 14 - 24 hours). RESULTS: After a single dose, the ΔTpH≥4 (%) of R-LPZ, LPZ, S-PPZ and PPZ was 56.6 ± 19.6, 53.1 ± 23.3, 35.6 ± 24.9 and 26.8 ± 30.2, respectively. The ΔTpH≥6 (%) was 50.7 ± 26.1, 41.4 ± 26.2, 25.4 ± 24.9 and 22.1 ± 27.6, respectively. The ΔAUECph-τ1-τ was 45,564 ± 16,107, 41,798 ± 16,153, 31,914 ± 17,304 and 20,744 ± 21,500, respectively. Statistically significant differences were found with R-LPZ vs. S-PPZ, R-LPZ vs. PPZ, LPZ vs. S-PPZ and LPZ vs. PPZ. The average TpH≥4 of R-LPZ, LPZ, S-PPZ, and PPZ was (47.2 ± 26.1) minutes, (49.6 ± 19.3) minutes, (56.1 ± 23.7) minutes, and (72.1 ± 27.3) minutes, respectively. Statistically significant differences were found with R-LPZ vs. PPZ (p = 0.009) and LPZ vs. PPZ (p = 0.019). After multiple doses, the ΔTpH≥4 (%) of R-LPZ, LPZ, S-PPZ, and PPZ was 71.7 ± 20.2, 63.5 ± 19.4, 59.5 ± 17.8 and 64.0 ± 22.4, respectively. The ΔTpH≥6 (%) was 64.0 ± 22.2, 52.0 ± 19.2, 49.6 ± 20.4 and 50.9 ± 23.8, respectively. The ΔAUECph-τ1-τ was 326,149 ± 94,839, 288,565 ± 93,279, 296,189 ± 83,412 and 300,960 ± 108,057, respectively. No statistically significant differences were found in baseline-adjusted PD parameters during all time periods after multiple doses. CONCLUSION: After a single dose, the mean gastric pH inhibition value of R-LPZ was the highest, followed by LPZ, then S-PPZ and PPZ. R-LPZ and LPZ provided significantly better pH control compared with PPZ and S-PPZ in healthy subjects. The onset time of R-LPZ was the fastest and R-LPZ can provide better acid inhibition during sleeping time. After multiple doses, the mean values in all PD parameters of R-LPZ were the highest, the values of LPZ, S-PPZ, and PPZ were similar. However, no significant difference was found in acid inhibition among these four drugs after multiple doses.

Safety, pharmacokinetics, and pharmacodynamics of S-(-)-pantoprazole sodium injections after single and multiple intravenous doses in healthy Chinese subjects.

PURPOSE: The objective of this study was to evaluate the safety, pharmacokinetics, and pharmacodynamics of S-(-)-pantoprazole (PPZ) sodium injections following single and multiple intravenous doses in healthy Chinese subjects. METHODS: The dosage groups were set as followed: 20 mg of single and multiple intravenous administration of S-(-)-PPZ, 40 mg of single and multiple intravenous administration of S-(-)-PPZ or pantoprazole, and 80 mg of single dosage group of S-(-)-PPZ. Subjects were sampled for pharmacokinetic analysis and were monitored for 24-h intragastric pH prior to and 48-h intragastric pH after administration for the pharmacodynamic study. The pharmacokinetic and pharmacodynamic parameters were compared between S-(-)-PPZ and PPZ. Safety was evaluated on the basis of adverse events, vital signs, laboratory tests, and physical examination. RESULTS: All adverse events were mild and of limited duration. Maximum plasma concentration and area under the concentration-time curve for S-(-)-PPZ were dose proportional over the range of 20-80 mg following a single intravenous administration. Elimination rate constant and half-life observed statistical difference from a single dose to multiple doses in 40 mg of S-(-)-PPZ groups. After administration of a single dose, the mean 24-h intragastric pH value was observed higher in 80-mg group than in 40- and 20-mg groups. Slightly increase of intragastric pH was found after a single dose of 40 mg S-(-)-PPZ than 40 mg PPZ; however, the differences were not statistically significant. CONCLUSIONS: Twice daily of 40 mg S-(-)-PPZ sodium injections is effective in achieving satisfying acid inhibition. Compared with plasma R-(+)-PPZ levels, most subjects presented more potent and prolonged suppression of gastric acid of S-(-)-PPZ, while a few subjects showed faster metabolic rate of S-(-)-PPZ in vivo.

A chiral LC-MS/MS method for the enantioselective determination of R-(+)- and S-(-)-pantoprazole in human plasma and its application to a pharmacokinetic study of S-(-)-pantoprazole sodium injection.

Pantoprazole, a proton pump inhibitor, is clinically used for the treatment of peptic diseases. An enantioselective LC-MS/MS method was developed and validated for the simultaneous determination of pantoprazole enantiomers in human plasma. Pantoprazole enantiomers and the internal standard were extracted from plasma using acetonitrile. Chiral separation was carried on a Chiralpak IE column using the mobile phase consisted of 10 mm ammonium acetate solution containing 0.1% acetic acid-acetonitrile (28 : 72, v/v). MS analysis was performed on an API 4000 mass spectrometer. Multiple reactions monitoring transitions of m/z 384.1→200.1 and 390.1→206.0 were used to quantify pantoprazole enantiomers and internal standard, respectively. For each enantiomer, no apparent matrix effect was found, the calibration curve was linear over 5.00-10,000 ng/mL, the intra- and inter-day precisions were below 10.0%, and the accuracy was within the range of -5.6% to 0.6%. This method was applied to the stereoselective pharmacokinetic studies in human after intravenous administration of S-(-)-pantoprazole sodium injections. No chiral inversion was observed during sample storage, preparation procedure and analysis. While R-(+)-pantoprazole was detected in human plasma with a slightly high concentration, which implied that S-(-)-pantoprazole may convert to R-(+)-pantoprazole in some subjects.

Safety, tolerability, pharmacokinetics and pharmacodynamics of dexlansoprazole injection in healthy Chinese subjects.

PURPOSE: This study was conducted to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of dexlansoprazole injection in healthy subjects. METHODS: Dexlansoprazole (20-90 mg) or lansoprazole (30 mg) was administrated intravenously to healthy male and female volunteers. All the subjects were sampled for pharmacokinetic (PK) analysis and 64 of them were monitored for 24-h intragastric pH prior to and after administration in the pharmacodynamic (PD) study. RESULTS: Maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC0-τ) for dexlansoprazole injection was dose-proportional over the range of 20-90 mg following a single intravenous administration. Total clearance and half-life (t1/2) was independent of dose, and ranged from 4.69 L/h to 5.85 L/h and from 1.24 h to 2.17 h, respectively. A single dose of dexlansoprazole (30 mg) resulted in higher gastric pH compared to that of lansoprazole, evidenced by a mean 24-h gastric pH of 6.1 ± 1.2 (lansoprazole: 5.4 ± 1.1) and 24-h gastric pH > 6 post drug dose holding time of 64.2 ± 21.0% (lansoprazole: 49.5 ± 21.5%). CONCLUSION: Dexlansoprazole injection was safe and well tolerated for up to 5-day repeated intravenous administration dose of 30 mg. The recommended dosage for dexlansoprazole injection is 30 mg for an adequate gastric acid control.

Hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry method for the simultaneous determination of l-valine, l-leucine, l-isoleucine, l-phenylalanine, and l-tyrosine in human serum.

l-Valine, l-leucine, l-isoleucine, l-phenylalanine, and l-tyrosine are important proposed biomarkers for the early detection and diagnosis of type 2 diabetes. A simple and selective hydrophilic interaction chromatography with tandem mass spectrometry method was developed for the simultaneous determination of these amino acids in human serum, using stable isotope-labeled amino acids as internal standards. Chromatographic separation was carried out on a Syncronis HILIC column (150 mm × 2.1 mm, 5 µm) with the column temperature of 35°C and a mobile phase consisted of acetonitrile/120 mM ammonium acetate (89:11, v/v), and the run time was 11.0 min. The mass spectrometric analysis was performed using a QTRAP 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. As these five amino acids are endogenous compounds in serum, we used the corresponding stable isotope-labeled amino acids to evaluate the matrix effect and recovery in serum. The matrix effect was 98.7-107.3%, and the recovery was 92.7-102.3%. Calibration curves spiked unlabeled amino acids in water were linear over the range of 0.200-100 µg/mL. The accuracy, inter-, and intraday precision were below 10.2%. Analytes were stable during the study. This assay method has been validated and applied to the early diagnosis research of type 2 diabetes.

Enantioselective determination of (R)- and (S)-lansoprazole in human plasma by chiral liquid chromatography with mass spectrometry and its application to a stereoselective pharmacokinetic study.

A simple and enantioselective method was developed and validated for the simultaneous determination of (R)- and (S)-lansoprazole in human plasma by chiral liquid chromatography with tandem mass spectrometry. Lansoprazole enantiomers and internal standard (esomeprazole) were extracted from plasma using acetonitrile as protein precipitating agent. Baseline chiral separation was achieved within 9.0 min on a Chiralpak IC column (150 mm × 4.6 mm, 5 µm) with the column temperature of 30°C. The mobile phase consisted of 10 mM ammonium acetate solution containing 0.05% acetic acid/acetonitrile (50:50, v/v). The mass spectrometric analysis was performed using a QTrap 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. The multiple reactions monitoring transitions of m/z 370.1→252.1 and 346.1→198.1 were used to quantify lansoprazole enantiomers and esomeprazole, respectively. For each enantiomer, no apparent matrix effect was found, the calibration curve was linear over 5.00-3000 ng/mL, the intra- and inter-day precisions were below 10.0%, and the accuracy was -3.8 to 3.3%. Analytes were stable during the study. No chiral inversion was observed during sample storage, preparation procedure and analysis. The method was applied to the stereoselective pharmacokinetic studies in human after intravenous administration of dexlansoprazole or racemic lansoprazole.