Hydrogen sulfide and nitric oxide regulate the adaptation to iron deficiency through affecting Fe homeostasis and thiol redox modification in Glycine max seedlings.

Iron (Fe) is a vital microelement required for the growth and development of plants. Hydrogen sulfide (H2S) and nitric oxide (NO), as messenger molecules, participated in the regulation of plant physiological processes. Here, we studied the interaction effects of H2S and NO on the adaptation to Fe deficiency in Glycine max L. Physiological, biochemical and molecular approaches were conducted to analyze the role of H2S and NO in regulating the adaptation to Fe deficiency in soybean. We found that H2S and NO had obvious rescuing function on the Fe deficiency-induced the plant growth inhibition, which was significantly correlated with the increase in Fe content in the leaves, stems, and roots of soybean. Meanwhile, H+-flux, ferric chelate reductase (FCR) activity, and root apoplast Fe content were significantly affected by H2S and NO. Under Fe deficiency conditions NO and H2S regulated the expression of genes related to Fe homeostasis. Moreover, photosynthesis (Pn) and photosystem II (PSII) efficiency were enhanced by H2S and NO, and thiol redox modification was important for regulating the adaptation of Fe deficiency. The aforementioned affirmative influences caused by H2S and NO were also totally reversed by cPTIO (a NO scavenger). Our results suggested that H2S might act upstream of NO in response to Fe deficiency by affecting the Fe homeostasis enzyme activities and gene expression, and by promoting Fe accumulation in plant tissues as well as by enhancing thiol redox modification and photosynthesis in soybean plants.

Study on the proteins-luminol binding by use of luminol as a fluorescence probe.

In this paper, a new mathematical equation of lg(F0-F)/F=1/nlg[P]+1/nlgKa, which was used to obtain interaction parameters (the binding constant Ka and the number of binding sites n) between the protein and the small molecule ligand by using the ligand as a fluorescence (FL) probe, was constructed for the first time. The interaction parameters between myoglobin, catalase, lysozyme, bovine serum albumin (BSA) and luminol were obtained by this equation with luminol used as a FL probe, showing that the binding constants Ka were 8.78×10(5), 4.47×10(5), 4.21×10(4) and 3.95×10(4) respectively, and the number of binding sites n approximately equaled to 1.0 for myoglobin, catalase, and 2.0 for lysozyme, BSA. The interactions of ferritin, ovalbumin, aldolase, chymotrypsinogen and ribonuclease with luminol were also studied by this method. The binding constants Ka were at 10(4)-10(5) level, and the number of binding sites n mostly approximately equaled to 2.0. The binding ability of luminol to the studied proteins followed the pattern: myoglobin>aldolase>ferritin>ovalbumin>catalase>ribonuclease>lysozyme>BSA>chymotrypsinoge.

Determination of cytochrome c in human serum and pharmaceutical injections using flow injection chemiluminescence.

It was found that the complex of cytochrome c (Cyt c) and hydrogen peroxide could significantly catalyze the chemiluminescence (CL) reaction from luminol-hydrogen peroxide, and a sensitive, rapid, and simple CL procedure was proposed for the determination of Cyt c in a flow injection system for the first time. The increment of CL intensity was linear over the concentration of Cyt c ranging from 5 to 700 ng ml(-1), with a detection limit of 2 ng ml(-1) (3sigma). At a flow rate of 2.0 ml min(-1), a complete analytical process could be performed in 30 s with a relative standard deviation of less than 4.0%. The proposed method was applied successfully for the assay of Cyt c in pharmaceutical injections and human serum, and the recoveries were from 98.0% to 108.8% and 92.5% to 109.0%. The possible mechanism of Cyt c enhanced CL reaction was also discussed.

Sensitive determination of gentiopicroside in medicine and bio-fluids using luminol-myoglobin chemiluminescence combined with flow injection technique.

A novel chemiluminescence method for the determination of gentiopicroside is presented, which was based on the inhibitory effect of gentiopicroside on the chemiluminescence reaction between luminol and myoglobin in a flow-injection system. The decrement of chemiluminescence intensity was linear with the logarithm of gentiopicroside concentration over the range from 10.0 pg mL(-1) to 500.0 ng mL(-1) (r(2) = 0.9992), with a detection limit of 3.0 pg mL(-1) (3σ). At a flow rate of 2.0 mL min(-1), a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0% (n = 5). The proposed procedure was applied successfully in the determination of gentiopicroside in pharmaceutical preparations, human urine and serum without any pretreatment procedure. The possible mechanism of the reaction was also discussed.

A study of the chemiluminescence behavior of cephalosporins with luminol and its analytical application.

The chemiluminescence intensity of luminol-dissolved oxygen was decreased when cephalosporins were mixed with luminol. The decrease chemiluminescence intensity was linear with the logarithm of cephalosporins concentration over the range from nanogram to microgramme level, with the limits of detection at nanogram level. The sensitivities of determination for cephalosporins were in the order of cefoperazone > ceftriaxone > cefuroxime > cefaclor > cefalexin > cefradine. The proposed method was applied to monitor the excretion of cefradine in human urine after taken cefradine capsules. The possible chemiluminescence mechanism and relationship between the determination sensitivities and generations of cephalosporins were also discussed.

A sensitive chemiluminescence procedure for the determination of carbon monoxide with myoglobin-luminol chemiluminescence system.

A novel chemiluminescence method combined with the flow injection technique for the determination of carbon monoxide is presented in this paper. The chemiluminescence signal based on the reaction between myoglobin and luminol in an alkaline medium was remarkably enhanced by carbon monoxide. The enhanced chemiluminescence intensity was linear with carbon monoxide concentration in the range from 0.01 to 10.0 pmol.L(-1), and the detection limit was 3x10(-3) pmol.L(-1) (3sigma). The whole process, including sampling and washing, could be completed in 0.5 min with a relative standard deviation of less than 4.0%. The proposed method was applied successfully in the assay of carbon monoxide in human serum and artificial water samples without any pretreatment procedure.

In vitro monitoring chlorogenic acid in human urine and serum by a flow injection system exploiting the luminol-dissolved oxygen chemiluminescence reaction.

A sensitive flow injection chemiluminescence method, based on the inhibitory effect of chlorogenic acid on the reaction between luminol and dissolved oxygen, was presented for the determination of chlorogenic acid. It was found that the decrease of chemiluminescence intensity was linear with the logarithm of chlorogenic acid concentration over the range from 1.0 ng.ml(-1) to 100 ng.ml(-1) (r(2) = 0.9978), with the detection limit of 0.3 ng.ml(-1) (3 sigma). At the flow rate of 2.0 ml.min(-1) for each line, a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation lower than 3.0% (n = 5). The proposed procedure was applied successfully to determine chlorogenic acid in Flo Lonicerae for different drawn time and monitor the excretion of chlorogenic acid in human urine. It was found that the excretive amounts of chlorogenic acid in urine reached its maximum in 2 hours after intake of Flo Lonicerae tea, presenting an excretive ratio of 63.82% in 6 hours. With urinary excretion rate method, the total elimination rate constant k and half-life time t(1/2) of chlorogenic acid was calculated, which were 0.7667 and 0.91 hours, respectively.