To optimize fitness, plants must efficiently allocate their resources between growth and defense. Although phytohormone crosstalk has emerged as a major player in balancing growth and defense, the genetic basis by whi...To optimize fitness, plants must efficiently allocate their resources between growth and defense. Although phytohormone crosstalk has emerged as a major player in balancing growth and defense, the genetic basis by which plants man age this balance remai ns elusive. We previously ide ntified a quantitative disease . resistance locus, qRfg2, in maize (Zea mays) that protects against the fungal disease Gibberella stalk rot. Here, through map-based cloning, we demonstrate that the causal gene at qRfg2 is ZmAuxRPI, which encodes a plastid stroma-localized auxin-regulated protein. ZmAuxRPI responded quickly to pathogen challenge with a rapid yet transient reduction in expression that led to arrested root growth but enhanced resista nee to Gibberella stalk rot and Fusarium ear rot. ZmAuxRPI was show n to promote the biosynthesis of indole-3-acetic acid (IAA), while suppressing the formation of benzoxazinoid defense compounds. ZmAuxRPI presumably acts as a resource regulator modulating indole-3-glycerol phosphate and/or indole flux at the branch point between the IAA and benzoxazinoid biosynthetic pathways. The concerted interplay between IAA and benzoxazinoids can regulate the growth-defense balance in a timely and efficient manner to optimize plant fitness.展开更多
Plant growth-promoting rhizobacteria （PGPR） are considered to be the most promising agents for cash crop production via increasing crop yields and decreasing disease occurrence. The Bacillus amyloliquefaciens strain...Plant growth-promoting rhizobacteria （PGPR） are considered to be the most promising agents for cash crop production via increasing crop yields and decreasing disease occurrence. The Bacillus amyloliquefaciens strain W19 can produce secondary metabolites （iturin and bacillomycin D） effectively against Fusarium oxysporum f. sp. cubense （FOC）. In this study, the ability of a bio-organic fertilizer （BIO） containing strain W19 to promote plant growth and suppress the Fusarium wilt of banana was evaluated in both pot and field experiments. The results showed that application of BIO significantly promoted the growth and fruit yield of banana while suppressing the banana Fusariurn wilt disease. To further determine the beneficial mechanisms of the strain, the colonization of green fluorescent protein-tagged strain W19 on banana roots was observed using confocal laser scanning microscopy and scanning electron microscopy. The effect of banana root exudates on the formation of biofilm of strain W19 indicated that the banana root exudates may enhance colonization. In addition, the strain W19 was able to produce indole-3-acetic acid （IAA）, a plant growth-promoting hormone. The results of these experiments revealed that the application of strain W19-enriched BIO improved the banana root colonization of strain W19 and growth of banana and suppressed the Fusarium wilt. The PGPR strain W19 can be a useful biocontrol agent for the production of banana under field conditions.展开更多
The plant tryptophan （Trp） biosynthetic pathway produces many secondary metabolites with diverse functions. Indole- 3-acetic acid （IAA）, proposed as a derivative from Trp or its precursors, plays an essential role...The plant tryptophan （Trp） biosynthetic pathway produces many secondary metabolites with diverse functions. Indole- 3-acetic acid （IAA）, proposed as a derivative from Trp or its precursors, plays an essential role in plant growth and development. Although the Trp-dependant and Trp-independent IAA biosynthetic pathways have been proposed, the enzymes, reactions and regulatory mechanisms are largely unknown. In Arabidopsis, indole-3-glycerol phosphate （IGP） is suggested to serve as a branchpoint component in the Trp-independent IAA biosynthesis. To address whether other enzymes in addition to Trp synthase ~ （TSA1） catalyze IGP cleavage, we identified and characterized an indole synthase （INS） gene, a homolog of TSA1 in Arabidopsis. INS exhibits different subcellular localization from TSA1 owing to the lack of chloroplast transit pepUde （cTP）. In si//co data show that the expression levels of INS and TSA1 in all examined organs are quite different. Histochemical staining of INS promoter-GUS transgenic lines indicates that INS is expressed in vascular tissue of cotyledons, hypocotyls, roots and rosette leaves as well as in flowers and siliques. INS is capable of complementing the Trp auxotrophy of Escherichia co// AtrpA strain, which is defective in Trp synthesis due to the deletion of TSA. This implies that INS catalyzes the conversion of IGP to indole and may be involved in the biosynthesis of Trp-independent IAA or other secondary metabolites in Arabidopsis.展开更多
AIM： To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid （IAA） in combination with horseradish peroxidase （HRP）. METHODS： BXPC-3 cells deriv...AIM： To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid （IAA） in combination with horseradish peroxidase （HRP）. METHODS： BXPC-3 cells derived from human pancreatic cancer were exposed to 40 or 80 μmol/L IAA and 1.2 μg/mL HRP at different times. Then, Mn- assay was used to detect the cell proliferation. Flow cytometry was performed to analyze cell cycle. Terminal deoxynucleotidyl transferasemediated dUTP nick end labeling assay was used to detect apoptosis. 2,7-Dichlorofluorescin diacetate uptake was measured by confocal microscopy to determine free radicals. Level of malondialdehyde （MDA） and activity of superoxide dismutase （SOD） were measured by biochemical methods. RESULTS： IAA/HRP initiated growth inhibition of BXPC-3 cells in a dose- and time-dependent manner. Flow cytometry revealed that the cells treated for 48 h were arrested at G1/G0. After exposure to 80 μmol/L IAA plus 1.2 μg/mL HRP for 72 h, the apoptosis rate increased to 72.5‰, which was nine times that of control. Content of MDA and activity of SOD increased respectively after treatment compared to control. Meanwhile, IAA/HRP stimulated the formation of free radicals. CONCLUSION： The combination of IAA and HRP can inhibit the growth of human pancreatic cancer BXPC-3 cells in vitro by inducing apoptosis.展开更多
A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are sti...A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still unclear.Here,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial roots.The main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly increased.In addition,the average LR density of 2nd whorl crown root under mixed N was also increased.Compared with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further exploration.Meanwhile,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this conclusion.Furthermore,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this pathway.This study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.展开更多
Tillering is an important agronomic trait of rice(Oryza sativa)that affects the number of effective panicles,thereby affecting yields.The phytohormone auxin plays a key role in tillering.Here we identified the high ti...Tillering is an important agronomic trait of rice(Oryza sativa)that affects the number of effective panicles,thereby affecting yields.The phytohormone auxin plays a key role in tillering.Here we identified the high tillering and semi-dwarf 1(htsd1)mutant with auxin-deficiency root characteristics,such as shortened lateral roots,reduced lateral root density,and enlarged root angles.htsd1 showed reduced sensitivity to auxin,but the external application of indole-3-acetic acid(IAA)inhibited its tillering.We identified the mutated gene in htsd1 as AUXIN1(OsAUX1,LOC_Os01g63770),which encodes an auxin influx transporter.The promoter sequence of OsAUX1 contains many SQUAMOSA PROMOTER BINDING PROTEIN-LIKE(SPL)binding sites,and we demonstrated that SPL7 binds to the OsAUX1 promoter.TEOSINTE BRANCHED1(OsTB1),a key gene that negatively regulates tillering,was significantly downregulated in htsd1.Tillering was enhanced in the OsTB1 knockout mutant,and the external application of IAA inhibited tiller elongation in this mutant.Overexpressing OsTB1 restored the multi-tiller phenotype of htsd1.These results suggest that SPL7 directly binds to the OsAUX1 promoter and regulates tillering in rice by altering OsTB1 expression to modulate auxin signaling.展开更多
Sulfur is an essential macronutrient for plants with numerous biological functions. However, the influence of sulfur nutrient availability on the regulation of root development remains largely unknown. Here, we report...Sulfur is an essential macronutrient for plants with numerous biological functions. However, the influence of sulfur nutrient availability on the regulation of root development remains largely unknown. Here, we report the response of Arabidopsis thaliana L. root development and growth to different levels of sulfate, demonstrating that low sulfate levels promote the primary root elongation. By using various reporter lines, we examined in vivo IAA level and distribution, cell division,and root meristem in response to different sulfate levels.Meanwhile the dynamic changes of in vivo cysteine, glutathione,and IAA levels were measured. Root cysteine, glutathione, and IAA levels are positively correlated with external sulfate levels in the physiological range, which eventually affect root system architecture. Low sulfate levels also downregulate the genes involved in auxin biosynthesis and transport, and elevate the accumulation of PLT1 and PLT2. This study suggests that sulfate level affects the primary root elongation by regulating the endogenous auxin level and root stem cell niche maintenance.展开更多
The effects of neodymium nitrate （Nd^3＋） on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3＋ （5 μmol/L） to culture medium significantly increased rooting fre...The effects of neodymium nitrate （Nd^3＋） on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3＋ （5 μmol/L） to culture medium significantly increased rooting frequency. Histological investigation showed that Nd^3＋ did not change the process of root initiation. Nd^3＋ did not influence total endogenous cytokinin levels, but significantly increased the level of endogenous indole-3-acetic acid （IAA） in the base of shoot cuttings. Compared to the control, the ratio of IAA/cytokinins was very high in the Nd^3＋ treatment. These results suggested that the enhanced rooting frequency may be related to the increase in endogenous IAA level in Nd^3＋ treatment. Analysis of enzyme activities showed that the enhanced accumulation of the endogenous IAA by Nd^3＋ should not be attributed to inhibition of IAA decomposition by IAA oxidase or promotion of cytokinin decomposition by cytokinin oxidase. Besides, Nd^3＋ increased the ratio of reduced glutathione （GSH） and oxidized glutathione （GSSG） in the process of adventitious rooting while the ratio of ascorbate （ASC） to dehydroascorbate （DHA） was not affected.展开更多
Plant associated bacteria are promising alternatives to chemical fertilizers for plant growth and yield improvement in an eco-friendly manner.In this study,rice associated bacteria were isolated and assessed for miner...Plant associated bacteria are promising alternatives to chemical fertilizers for plant growth and yield improvement in an eco-friendly manner.In this study,rice associated bacteria were isolated and assessed for mineral phosphate solubilization and indole-3-acetic acid(IAA) production activity in vitro.Six promising strains,which were tentatively identified as phylotaxon Pseudochrobactrum sp.(BRRh-1),Burkholderia sp.(BRRh-2),Burkholderia sp.(BRRh-3),Burkholderia sp.(BRRh-4),Pseudomonas aeruginosa(BRRh-5 and BRRh-6) based on their 16 S rRNA gene phylogeny,exhibited significant phosphate solubilizing activity in National Botanical Research Institute phosphate growth medium,and BRRh-4 displayed the highest phosphate solubilizing activity,followed by BRRh-5.The p H of the culture broth declined,resulting in increase of growth rate of bacteria at p H 7,which might be due to organic acid secretion by the strains.In presence of L-tryptophan,five isolates synthesized IAA and the maximum IAA was produced by BRRh-2,followed by BRRh-1.Application of two most efficient phosphate solubilizing isolates BRRh-4 and BRRh-5 by root dipping(colonization) of seedling and spraying at the flowering stage significantly enhanced the growth and grain yield of rice variety BRRI dhan-29.Interestingly,application of both strains with 50% of recommended nitrogen,phosphorus and potassium fertilizers produced equivalent or higher grain yield of rice compared to the control grown with full recommended fertilizer doses,which suggests that these strains may have the potential to be used as bioinoculants for sustainable rice production.展开更多
Platinum nanowire （PtNW） can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm. The PtNW and multiwalled carbon nanotubes （CNT） are then dispersed int...Platinum nanowire （PtNW） can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm. The PtNW and multiwalled carbon nanotubes （CNT） are then dispersed into chitosan （CHIT） solution. The resulting PtNW-CNT-CHIT material brings new capabilities for electrochemical devices by using the synergistic action of the electrocatalytic activity of PtNW and CNT. By dropping the PtNW-CNT-CHIT film onto the glassy carbon （GO） electrode surface, and after evaporation an amperometric sensor for the determination of indole-3-acetic acid （IAA） was developed. The oxidation current of IAA increased significantly at the PtNW-CNT-CHIT film coated GC electrode, in contrast to that at the CNT-CHIT modified GC. The linear response of the sensor is from 50 ng/ml to 50 μg/ml with a detection limit of 25 ng/mL.展开更多
A total of 79 bacteria and 101 actinobacteria strains were isolated from the sediment samples of the different points of Baratang mud volcano viz.,point of the eruption(M),middle of the volcano(MD),and the dried part ...A total of 79 bacteria and 101 actinobacteria strains were isolated from the sediment samples of the different points of Baratang mud volcano viz.,point of the eruption(M),middle of the volcano(MD),and the dried part of the mud volcano(E).Based on the biochemical and molecular characterization,the isolates were categorized under the phyla Proteobacteria,Firmicutes and Proteobacteria included representatives of Classes Alphaproteobacteria,Gammaproteobacteria and Deltaproteobacteria of 29 genera with 38 distinct ribotypes.Thirty-eight bacterial strains from four different regions of mud volcano revealed excellent activity for indole-3-acetic acid(IAA)production.Excellent antagonistic property,plant growth promoting properties such as IAA production,phosphate,potassium and zinc solubilization were identified in Bacillus megaterium NIOT_MV 31 strain of 38 studied isolates.In this study,we investigated the optimization of IAA production by B.megaterium NIOT_MV 31 and its formulation as a plant growth promoter to improve economic and agricultural development.Maximum IAA yield was achieved using optimal conditions(42.63 mg/mL)in the presence of optimized tryptophan after 4 days of incubation.Twofold increase in the plant growth parameters were observed to that of control plants.Optimization of culture conditions resulted in a fourfold increase in IAA production by B.megaterium NIOT_MV 31 cells.The results clearly demonstrated that,B.megaterium NIOT_MV 31 holds great potential as a source for IAA production and may be useful for commercial applications.展开更多
Given the consistent release of zinc oxide(ZnO)nanoparticles into the environment,it is urgent to study their impact on plants in depth.In this study,grains of rice were treated with two different concentrations of Zn...Given the consistent release of zinc oxide(ZnO)nanoparticles into the environment,it is urgent to study their impact on plants in depth.In this study,grains of rice were treated with two different concentrations of ZnO nanoparticles(NP-ZnO,10 and 100 mg/L),and their bulk counterpart(B-ZnO)were used to evaluate whether ZnO action could depend on particle size.To test this hypothesis,root growth and development assessment,oxidative stress parameters,indole-3-acetic acid(IAA)content and molecules/enzymes involved in IAA metabolism were analyzed.In situ localization of Zn in control and treated roots was also performed.Though Zn was visible inside root cells only following nanoparticle treatment,both materials(NP-ZnO and B-ZnO)were able to affect seedling growth and root morphology,with alteration in the concentration/pattern of localization of oxidative stress markers and with a different action depending on particle size.In addition,only ZnO supplied as bulk material induced a significant increase in both IAA concentration and lateral root density,supporting our hypothesis that bulk particles might enhance lateral root development through the rise of IAA concentration.Apparently,IAA concentration was influenced more by the activity of the catabolic peroxidases than by the protective action of phenols.展开更多
Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions;however,the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of...Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions;however,the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of saline stress in crops.This study aimed to evaluate the efficiency of plant growth-promoting rhizobacteria(PGPRs),isolated from the rhizosphere of halophile plants,for the growth,Na^+/K^+balance,ethylene emission,and gene expression of wheat seedlings{Triticum aestivum L.)grown under saline conditions(100 mmol L^-1 NaCl)for 14 d.A total of 118 isolates obtained from saline soils of the deserts of Iran were tested for their capacity as PGPRs.Out of the 118 isolates,17 could solubilize phosphate(Ca3(P〇4)2),5 could produce siderophores,and 16 could synthesize indole-3-acetic acid.Additionally,PGPRs were also evaluated for aminocyclopropane-l-carboxylate deaminase activity.A pot experiment was conducted to evaluate the ability of 28 PGPR isolates to promote growth,regulate Na^+/K^+balance,and decrease ethylene emissions in plants.The most efficient PGPRs were Arthrobacter aurescens.Bacillus atrophaeus,Enterobacter ashuriae,and Pseudomonas fluorescens.Gene expression analysis revealed the up-regulation of H^+-PPase,HKT1,NHX7,CAT,and APX expression in roots of Enterobacter-inocuVdied salt-stressed plants.Salt-tolerant rhizobacteria exhibiting plant growth-promoting traits can facilitate the growth of wheat plants under saline conditions.Our results indicate that the isolation of these bacteria may be useful for formulating new inoculants to improve wheat cropping systems in saline soils.展开更多
<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> It is not well analyze...<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> Ultra high-speed </span></span><span style="font-family:""><span style="font-family:Verdana;">liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive </span><span><span style="font-family:Verdana;">patients. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.展开更多
Plant growth regulators are biologically active signaling molecules that regulate a number of plant physiological processes. Auxin(indole-3-acetic acid) is an important plant growth regulator and is synthesized within...Plant growth regulators are biologically active signaling molecules that regulate a number of plant physiological processes. Auxin(indole-3-acetic acid) is an important plant growth regulator and is synthesized within plant tissues through L-tryptophan(L-TRP)-dependent and-independent pathways. It has been found that plants respond to exogenously applied L-TRP due to insufficient endogenous auxin biosynthesis. The exogenous application of L-TRP is highly significant for normal plant growth and development.L-tryptophan is applied through foliar spray, seed priming, and soil application. Soil-applied L-TRP is either directly taken up by plants or metabolized to auxin by soil microbiota and then absorbed by plant roots. Similarly, foliar spray and seed priming with L-TRP stimulates auxin synthesis within plants and improves the growth and productivity of agricultural crops. Furthermore, L-TRP contains approximately 14% nitrogen(N) in its composition, which is released upon its metabolism within a plant or in the rhizosphere and plays a role in enhancing crop productivity. This review deals with assessing crop responses under the exogenous application of L-TRP in normal and stressed environments, mode of action of L-TRP, advantages of using L-TRP over other auxin precursors, and role of the simultaneous use of L-TRP and auxin-producing microbes in improving the productivity of agricultural crops. To the best of our knowledge, this is the first review reporting the importance of the use of L-TRP in agriculture.展开更多
Background: No research has been done for the determination of plasma levels of tryptophan metabolites in patients of monopolar and bipolar depression. Methods: Ultra high-speed liquid chromatography/mass spectrometry...Background: No research has been done for the determination of plasma levels of tryptophan metabolites in patients of monopolar and bipolar depression. Methods: Ultra high-speed liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive patients. Results: No significant age and gender differences were shown in monopolar depressive patients and some differences were shown in bipolar patients. The administration of drugs such as antidepressants, antipsychotics, mood stabilizers do not seem to have affected the results. Conclusion: In patients of major monopolar depression age and gender differences of plasma levels of tryptophan metabolites disappear although significant differences are observed in healthy volunteers. Some differences of age and gender differences were shown between monopolar and bipolar depressive patients.展开更多
Background: Tryptophan metabolism plays important roles in health and diseases. Although simultaneous measurements of tryptophan metabolites are successfully measured, influences of age, gender, and clot formation on ...Background: Tryptophan metabolism plays important roles in health and diseases. Although simultaneous measurements of tryptophan metabolites are successfully measured, influences of age, gender, and clot formation on the measurements have not been reported. Methods: We took blood from young and old Japanese men and women and compared plasma levels of tryptophan metabolites. We also took plasma and serum from the blood of middle-aged men (n = 10). Metabolites analysis was performed by a liquid chromatograph tandem mass spectrometer, the LCMS-8060 quadrupole mass spectrometer combined with Nexera X2 liquid chromatograph system (Shimadzu Corporation, Kyoto, Japan). Body mass index (BMI) and TRP metabolites have been measured in healthy young men (n = 48), young women (n = 47), old men (n = 44), and old women (n = 39). TRP metabolites were measured by using the ultrahigh speed liquid chromatography-mass spectroscopy (Shimadzu Corporation). Results: Tryptophan and its metabolites such as serotonin, 5-hydroxyindole acetic acid, indole-3-acetic acid, kynurenine, anthranilic acid, were higher in young women and old men than young men and old women. Plasma levels of 3-hydroxykynurenine and xanthurenic acid were lower in young women and old men. Comparison of plasma and serum indicates that most of metabolites were higher in serum than plasma except for 3-hydroxy-kynurenine and quinolinic acid. Conclusion: Metabolites of the upper stream of degradation of tryptophan were higher in young women and old men than young men and old women, which suggests that the degradation of tryptophan was accelerated in young men and old women than young women and old men. Serum preparation may activate tryptophan degradation resulting in higher levels of metabolites in serum than in plasma.展开更多
The influence of exogenic hormones (indole-3-acetic acid (IAA), abscisic acid (ABA) and kinetin) on defense reaction of wheat (Triticum aestivum L.) calli to the bunt agent Tilletia caries (D.C.) Tul. & C. Tul. wa...The influence of exogenic hormones (indole-3-acetic acid (IAA), abscisic acid (ABA) and kinetin) on defense reaction of wheat (Triticum aestivum L.) calli to the bunt agent Tilletia caries (D.C.) Tul. & C. Tul. was studied. ABA and kinetin induced the oxalate oxidase activity, increased the Н2О2 level, decreased germination of fungi teliospores and induced on calli the occurrence of dense sites non-infected by pathogen. On the contrary, IAA led to the decrease of oxalate oxidase activity, loosening of calli and increase germination of bunt agent teliospores and growth of fungi mycelium, besides stimulated rhizoids formation of wheat calli. Probably, the accumulation of Н2О2 in wheat calli under the influence of kinetin and ABA connected with activity of oxalate oxidase is one of the factors increasing defense reaction of wheat to bunt agent.展开更多
A novel graphene oxide （GO） doped poly（hydroxymethylated-3,4-ethylenedioxythiophene） （PEDOTM） film has been achieved via one-step co-electrodeposition and utilized for electrochemical studies of indole-3-acetic ...A novel graphene oxide （GO） doped poly（hydroxymethylated-3,4-ethylenedioxythiophene） （PEDOTM） film has been achieved via one-step co-electrodeposition and utilized for electrochemical studies of indole-3-acetic acid （IAA）. The incorporation of GO into PEDOTM film facilitated the electrocatalytic activity and exhibited a favorable interaction between the PEDOTM/GO film and the phytohormone during the oxidation of IAA. Under optimized conditions, differential pulse voltammetry and square wave voltammetry were used for the quantitative analysis of IAA, respectively, each exhibiting a wide linearity range from 0.6 μmol L-1 to 10 μmol L-1 and 0.05 μmol L-1 to 40 μmol L-1, good sensitivity with a low detection Iimit of 0.087 μmol L-1 and 0.033μmol L T, respectively, as well as good stability. With the notable advantages of a green, sensitive method, expeditious response and facile operation, the as-prepared PEDOTM/GO organic-inorganic composite film provides a promising platform for electrochemical studies of IAA.展开更多
基金the Ministry of Agriculture and Rural Affairs of the people's Republic of China (grant numbers 2018ZX0800917B) and the National Natural Science Foundation of China (31671704).
文摘To optimize fitness, plants must efficiently allocate their resources between growth and defense. Although phytohormone crosstalk has emerged as a major player in balancing growth and defense, the genetic basis by which plants man age this balance remai ns elusive. We previously ide ntified a quantitative disease . resistance locus, qRfg2, in maize (Zea mays) that protects against the fungal disease Gibberella stalk rot. Here, through map-based cloning, we demonstrate that the causal gene at qRfg2 is ZmAuxRPI, which encodes a plastid stroma-localized auxin-regulated protein. ZmAuxRPI responded quickly to pathogen challenge with a rapid yet transient reduction in expression that led to arrested root growth but enhanced resista nee to Gibberella stalk rot and Fusarium ear rot. ZmAuxRPI was show n to promote the biosynthesis of indole-3-acetic acid (IAA), while suppressing the formation of benzoxazinoid defense compounds. ZmAuxRPI presumably acts as a resource regulator modulating indole-3-glycerol phosphate and/or indole flux at the branch point between the IAA and benzoxazinoid biosynthetic pathways. The concerted interplay between IAA and benzoxazinoids can regulate the growth-defense balance in a timely and efficient manner to optimize plant fitness.
基金supported by the National Natural Science Foundation of China (Nos. 31572212 and 31372142)the National Key Basic Research Program of China (No. 2015CB150503)+5 种基金the Chinese Ministry of Science and Technology (No. 2013AA102802)the Natural Science Foundation of Jiangsu Province, China (No. BK20150059)the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions of Chinathe 111 Project of China (No. B12009)the National Training Program of Innovation and Entrepreneurship for Undergraduates of China (No. 201410307089)the "Qing Lan" Project of China
文摘Plant growth-promoting rhizobacteria （PGPR） are considered to be the most promising agents for cash crop production via increasing crop yields and decreasing disease occurrence. The Bacillus amyloliquefaciens strain W19 can produce secondary metabolites （iturin and bacillomycin D） effectively against Fusarium oxysporum f. sp. cubense （FOC）. In this study, the ability of a bio-organic fertilizer （BIO） containing strain W19 to promote plant growth and suppress the Fusarium wilt of banana was evaluated in both pot and field experiments. The results showed that application of BIO significantly promoted the growth and fruit yield of banana while suppressing the banana Fusariurn wilt disease. To further determine the beneficial mechanisms of the strain, the colonization of green fluorescent protein-tagged strain W19 on banana roots was observed using confocal laser scanning microscopy and scanning electron microscopy. The effect of banana root exudates on the formation of biofilm of strain W19 indicated that the banana root exudates may enhance colonization. In addition, the strain W19 was able to produce indole-3-acetic acid （IAA）, a plant growth-promoting hormone. The results of these experiments revealed that the application of strain W19-enriched BIO improved the banana root colonization of strain W19 and growth of banana and suppressed the Fusarium wilt. The PGPR strain W19 can be a useful biocontrol agent for the production of banana under field conditions.
基金the National Natural Science Foundation of China(30330040, 30221002)
文摘The plant tryptophan （Trp） biosynthetic pathway produces many secondary metabolites with diverse functions. Indole- 3-acetic acid （IAA）, proposed as a derivative from Trp or its precursors, plays an essential role in plant growth and development. Although the Trp-dependant and Trp-independent IAA biosynthetic pathways have been proposed, the enzymes, reactions and regulatory mechanisms are largely unknown. In Arabidopsis, indole-3-glycerol phosphate （IGP） is suggested to serve as a branchpoint component in the Trp-independent IAA biosynthesis. To address whether other enzymes in addition to Trp synthase ~ （TSA1） catalyze IGP cleavage, we identified and characterized an indole synthase （INS） gene, a homolog of TSA1 in Arabidopsis. INS exhibits different subcellular localization from TSA1 owing to the lack of chloroplast transit pepUde （cTP）. In si//co data show that the expression levels of INS and TSA1 in all examined organs are quite different. Histochemical staining of INS promoter-GUS transgenic lines indicates that INS is expressed in vascular tissue of cotyledons, hypocotyls, roots and rosette leaves as well as in flowers and siliques. INS is capable of complementing the Trp auxotrophy of Escherichia co// AtrpA strain, which is defective in Trp synthesis due to the deletion of TSA. This implies that INS catalyzes the conversion of IGP to indole and may be involved in the biosynthesis of Trp-independent IAA or other secondary metabolites in Arabidopsis.
基金Supported by the Natural Science Foundation of Shaanxi Province, No. 2003C215
文摘AIM： To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid （IAA） in combination with horseradish peroxidase （HRP）. METHODS： BXPC-3 cells derived from human pancreatic cancer were exposed to 40 or 80 μmol/L IAA and 1.2 μg/mL HRP at different times. Then, Mn- assay was used to detect the cell proliferation. Flow cytometry was performed to analyze cell cycle. Terminal deoxynucleotidyl transferasemediated dUTP nick end labeling assay was used to detect apoptosis. 2,7-Dichlorofluorescin diacetate uptake was measured by confocal microscopy to determine free radicals. Level of malondialdehyde （MDA） and activity of superoxide dismutase （SOD） were measured by biochemical methods. RESULTS： IAA/HRP initiated growth inhibition of BXPC-3 cells in a dose- and time-dependent manner. Flow cytometry revealed that the cells treated for 48 h were arrested at G1/G0. After exposure to 80 μmol/L IAA plus 1.2 μg/mL HRP for 72 h, the apoptosis rate increased to 72.5‰, which was nine times that of control. Content of MDA and activity of SOD increased respectively after treatment compared to control. Meanwhile, IAA/HRP stimulated the formation of free radicals. CONCLUSION： The combination of IAA and HRP can inhibit the growth of human pancreatic cancer BXPC-3 cells in vitro by inducing apoptosis.
基金supported by the National Natural Science Foundation of China(31421092)the Central Publicinterest Scientific Institution Basal Research Fund,China(1610232023023)。
文摘A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still unclear.Here,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial roots.The main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly increased.In addition,the average LR density of 2nd whorl crown root under mixed N was also increased.Compared with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further exploration.Meanwhile,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this conclusion.Furthermore,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this pathway.This study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.
基金This work was supported by the National Key Research and Development Program of China(2022YFD1201600)the National Natural Science Foundation of China(32171964)the Science Fund for Creative Research Groups of Chongqing,China(cstc2021jcyj-cxttX0004)。
文摘Tillering is an important agronomic trait of rice(Oryza sativa)that affects the number of effective panicles,thereby affecting yields.The phytohormone auxin plays a key role in tillering.Here we identified the high tillering and semi-dwarf 1(htsd1)mutant with auxin-deficiency root characteristics,such as shortened lateral roots,reduced lateral root density,and enlarged root angles.htsd1 showed reduced sensitivity to auxin,but the external application of indole-3-acetic acid(IAA)inhibited its tillering.We identified the mutated gene in htsd1 as AUXIN1(OsAUX1,LOC_Os01g63770),which encodes an auxin influx transporter.The promoter sequence of OsAUX1 contains many SQUAMOSA PROMOTER BINDING PROTEIN-LIKE(SPL)binding sites,and we demonstrated that SPL7 binds to the OsAUX1 promoter.TEOSINTE BRANCHED1(OsTB1),a key gene that negatively regulates tillering,was significantly downregulated in htsd1.Tillering was enhanced in the OsTB1 knockout mutant,and the external application of IAA inhibited tiller elongation in this mutant.Overexpressing OsTB1 restored the multi-tiller phenotype of htsd1.These results suggest that SPL7 directly binds to the OsAUX1 promoter and regulates tillering in rice by altering OsTB1 expression to modulate auxin signaling.
基金supported by grants from the National Natural Science Foundation of China (90917004 and 31140056)
文摘Sulfur is an essential macronutrient for plants with numerous biological functions. However, the influence of sulfur nutrient availability on the regulation of root development remains largely unknown. Here, we report the response of Arabidopsis thaliana L. root development and growth to different levels of sulfate, demonstrating that low sulfate levels promote the primary root elongation. By using various reporter lines, we examined in vivo IAA level and distribution, cell division,and root meristem in response to different sulfate levels.Meanwhile the dynamic changes of in vivo cysteine, glutathione,and IAA levels were measured. Root cysteine, glutathione, and IAA levels are positively correlated with external sulfate levels in the physiological range, which eventually affect root system architecture. Low sulfate levels also downregulate the genes involved in auxin biosynthesis and transport, and elevate the accumulation of PLT1 and PLT2. This study suggests that sulfate level affects the primary root elongation by regulating the endogenous auxin level and root stem cell niche maintenance.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060359006)
文摘The effects of neodymium nitrate （Nd^3＋） on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3＋ （5 μmol/L） to culture medium significantly increased rooting frequency. Histological investigation showed that Nd^3＋ did not change the process of root initiation. Nd^3＋ did not influence total endogenous cytokinin levels, but significantly increased the level of endogenous indole-3-acetic acid （IAA） in the base of shoot cuttings. Compared to the control, the ratio of IAA/cytokinins was very high in the Nd^3＋ treatment. These results suggested that the enhanced rooting frequency may be related to the increase in endogenous IAA level in Nd^3＋ treatment. Analysis of enzyme activities showed that the enhanced accumulation of the endogenous IAA by Nd^3＋ should not be attributed to inhibition of IAA decomposition by IAA oxidase or promotion of cytokinin decomposition by cytokinin oxidase. Besides, Nd^3＋ increased the ratio of reduced glutathione （GSH） and oxidized glutathione （GSSG） in the process of adventitious rooting while the ratio of ascorbate （ASC） to dehydroascorbate （DHA） was not affected.
基金the World Bank for major financial support through a sub-project CP # 2071 of Higher Education Quality Enhancement Project of the University Grants Commission of Bangladesh,Research Management Committee of Bangabandhu Sheikh Mujibur Rahman Agricultural University,Gazipur,Bangladesh,Ministry of Science and Technology of the Government of the People’s Republic of BangladeshPartial funding from a BAS-USDA project CR-11
文摘Plant associated bacteria are promising alternatives to chemical fertilizers for plant growth and yield improvement in an eco-friendly manner.In this study,rice associated bacteria were isolated and assessed for mineral phosphate solubilization and indole-3-acetic acid(IAA) production activity in vitro.Six promising strains,which were tentatively identified as phylotaxon Pseudochrobactrum sp.(BRRh-1),Burkholderia sp.(BRRh-2),Burkholderia sp.(BRRh-3),Burkholderia sp.(BRRh-4),Pseudomonas aeruginosa(BRRh-5 and BRRh-6) based on their 16 S rRNA gene phylogeny,exhibited significant phosphate solubilizing activity in National Botanical Research Institute phosphate growth medium,and BRRh-4 displayed the highest phosphate solubilizing activity,followed by BRRh-5.The p H of the culture broth declined,resulting in increase of growth rate of bacteria at p H 7,which might be due to organic acid secretion by the strains.In presence of L-tryptophan,five isolates synthesized IAA and the maximum IAA was produced by BRRh-2,followed by BRRh-1.Application of two most efficient phosphate solubilizing isolates BRRh-4 and BRRh-5 by root dipping(colonization) of seedling and spraying at the flowering stage significantly enhanced the growth and grain yield of rice variety BRRI dhan-29.Interestingly,application of both strains with 50% of recommended nitrogen,phosphorus and potassium fertilizers produced equivalent or higher grain yield of rice compared to the control grown with full recommended fertilizer doses,which suggests that these strains may have the potential to be used as bioinoculants for sustainable rice production.
基金supported by the NNSF of China(No.20435010,30540019,30670190 and 3060049)the Natural Science Foundation of Hunan Province(No.0JJY1003 and 05C306).
文摘Platinum nanowire （PtNW） can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm. The PtNW and multiwalled carbon nanotubes （CNT） are then dispersed into chitosan （CHIT） solution. The resulting PtNW-CNT-CHIT material brings new capabilities for electrochemical devices by using the synergistic action of the electrocatalytic activity of PtNW and CNT. By dropping the PtNW-CNT-CHIT film onto the glassy carbon （GO） electrode surface, and after evaporation an amperometric sensor for the determination of indole-3-acetic acid （IAA） was developed. The oxidation current of IAA increased significantly at the PtNW-CNT-CHIT film coated GC electrode, in contrast to that at the CNT-CHIT modified GC. The linear response of the sensor is from 50 ng/ml to 50 μg/ml with a detection limit of 25 ng/mL.
文摘A total of 79 bacteria and 101 actinobacteria strains were isolated from the sediment samples of the different points of Baratang mud volcano viz.,point of the eruption(M),middle of the volcano(MD),and the dried part of the mud volcano(E).Based on the biochemical and molecular characterization,the isolates were categorized under the phyla Proteobacteria,Firmicutes and Proteobacteria included representatives of Classes Alphaproteobacteria,Gammaproteobacteria and Deltaproteobacteria of 29 genera with 38 distinct ribotypes.Thirty-eight bacterial strains from four different regions of mud volcano revealed excellent activity for indole-3-acetic acid(IAA)production.Excellent antagonistic property,plant growth promoting properties such as IAA production,phosphate,potassium and zinc solubilization were identified in Bacillus megaterium NIOT_MV 31 strain of 38 studied isolates.In this study,we investigated the optimization of IAA production by B.megaterium NIOT_MV 31 and its formulation as a plant growth promoter to improve economic and agricultural development.Maximum IAA yield was achieved using optimal conditions(42.63 mg/mL)in the presence of optimized tryptophan after 4 days of incubation.Twofold increase in the plant growth parameters were observed to that of control plants.Optimization of culture conditions resulted in a fourfold increase in IAA production by B.megaterium NIOT_MV 31 cells.The results clearly demonstrated that,B.megaterium NIOT_MV 31 holds great potential as a source for IAA production and may be useful for commercial applications.
基金financed by local funding of the University of Pisa。
文摘Given the consistent release of zinc oxide(ZnO)nanoparticles into the environment,it is urgent to study their impact on plants in depth.In this study,grains of rice were treated with two different concentrations of ZnO nanoparticles(NP-ZnO,10 and 100 mg/L),and their bulk counterpart(B-ZnO)were used to evaluate whether ZnO action could depend on particle size.To test this hypothesis,root growth and development assessment,oxidative stress parameters,indole-3-acetic acid(IAA)content and molecules/enzymes involved in IAA metabolism were analyzed.In situ localization of Zn in control and treated roots was also performed.Though Zn was visible inside root cells only following nanoparticle treatment,both materials(NP-ZnO and B-ZnO)were able to affect seedling growth and root morphology,with alteration in the concentration/pattern of localization of oxidative stress markers and with a different action depending on particle size.In addition,only ZnO supplied as bulk material induced a significant increase in both IAA concentration and lateral root density,supporting our hypothesis that bulk particles might enhance lateral root development through the rise of IAA concentration.Apparently,IAA concentration was influenced more by the activity of the catabolic peroxidases than by the protective action of phenols.
基金This work was supported scientifically by COST Action ESI406“Soil fauna-Key to Soil Organic Matter Dynamics and Modelling(KEYSOM)”.
文摘Salinity is one of the most important growth-limiting factors for most crops in arid and semi-arid regions;however,the use of plant growth-promoting rhizobacteria isolated from saline soils could reduce the effects of saline stress in crops.This study aimed to evaluate the efficiency of plant growth-promoting rhizobacteria(PGPRs),isolated from the rhizosphere of halophile plants,for the growth,Na^+/K^+balance,ethylene emission,and gene expression of wheat seedlings{Triticum aestivum L.)grown under saline conditions(100 mmol L^-1 NaCl)for 14 d.A total of 118 isolates obtained from saline soils of the deserts of Iran were tested for their capacity as PGPRs.Out of the 118 isolates,17 could solubilize phosphate(Ca3(P〇4)2),5 could produce siderophores,and 16 could synthesize indole-3-acetic acid.Additionally,PGPRs were also evaluated for aminocyclopropane-l-carboxylate deaminase activity.A pot experiment was conducted to evaluate the ability of 28 PGPR isolates to promote growth,regulate Na^+/K^+balance,and decrease ethylene emissions in plants.The most efficient PGPRs were Arthrobacter aurescens.Bacillus atrophaeus,Enterobacter ashuriae,and Pseudomonas fluorescens.Gene expression analysis revealed the up-regulation of H^+-PPase,HKT1,NHX7,CAT,and APX expression in roots of Enterobacter-inocuVdied salt-stressed plants.Salt-tolerant rhizobacteria exhibiting plant growth-promoting traits can facilitate the growth of wheat plants under saline conditions.Our results indicate that the isolation of these bacteria may be useful for formulating new inoculants to improve wheat cropping systems in saline soils.
文摘<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> Ultra high-speed </span></span><span style="font-family:""><span style="font-family:Verdana;">liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive </span><span><span style="font-family:Verdana;">patients. </span><b><span style="font-family:Verdana;">Results:</span></b><span style="font-family:Verdana;"> There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.
文摘Plant growth regulators are biologically active signaling molecules that regulate a number of plant physiological processes. Auxin(indole-3-acetic acid) is an important plant growth regulator and is synthesized within plant tissues through L-tryptophan(L-TRP)-dependent and-independent pathways. It has been found that plants respond to exogenously applied L-TRP due to insufficient endogenous auxin biosynthesis. The exogenous application of L-TRP is highly significant for normal plant growth and development.L-tryptophan is applied through foliar spray, seed priming, and soil application. Soil-applied L-TRP is either directly taken up by plants or metabolized to auxin by soil microbiota and then absorbed by plant roots. Similarly, foliar spray and seed priming with L-TRP stimulates auxin synthesis within plants and improves the growth and productivity of agricultural crops. Furthermore, L-TRP contains approximately 14% nitrogen(N) in its composition, which is released upon its metabolism within a plant or in the rhizosphere and plays a role in enhancing crop productivity. This review deals with assessing crop responses under the exogenous application of L-TRP in normal and stressed environments, mode of action of L-TRP, advantages of using L-TRP over other auxin precursors, and role of the simultaneous use of L-TRP and auxin-producing microbes in improving the productivity of agricultural crops. To the best of our knowledge, this is the first review reporting the importance of the use of L-TRP in agriculture.
文摘Background: No research has been done for the determination of plasma levels of tryptophan metabolites in patients of monopolar and bipolar depression. Methods: Ultra high-speed liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive patients. Results: No significant age and gender differences were shown in monopolar depressive patients and some differences were shown in bipolar patients. The administration of drugs such as antidepressants, antipsychotics, mood stabilizers do not seem to have affected the results. Conclusion: In patients of major monopolar depression age and gender differences of plasma levels of tryptophan metabolites disappear although significant differences are observed in healthy volunteers. Some differences of age and gender differences were shown between monopolar and bipolar depressive patients.
文摘Background: Tryptophan metabolism plays important roles in health and diseases. Although simultaneous measurements of tryptophan metabolites are successfully measured, influences of age, gender, and clot formation on the measurements have not been reported. Methods: We took blood from young and old Japanese men and women and compared plasma levels of tryptophan metabolites. We also took plasma and serum from the blood of middle-aged men (n = 10). Metabolites analysis was performed by a liquid chromatograph tandem mass spectrometer, the LCMS-8060 quadrupole mass spectrometer combined with Nexera X2 liquid chromatograph system (Shimadzu Corporation, Kyoto, Japan). Body mass index (BMI) and TRP metabolites have been measured in healthy young men (n = 48), young women (n = 47), old men (n = 44), and old women (n = 39). TRP metabolites were measured by using the ultrahigh speed liquid chromatography-mass spectroscopy (Shimadzu Corporation). Results: Tryptophan and its metabolites such as serotonin, 5-hydroxyindole acetic acid, indole-3-acetic acid, kynurenine, anthranilic acid, were higher in young women and old men than young men and old women. Plasma levels of 3-hydroxykynurenine and xanthurenic acid were lower in young women and old men. Comparison of plasma and serum indicates that most of metabolites were higher in serum than plasma except for 3-hydroxy-kynurenine and quinolinic acid. Conclusion: Metabolites of the upper stream of degradation of tryptophan were higher in young women and old men than young men and old women, which suggests that the degradation of tryptophan was accelerated in young men and old women than young women and old men. Serum preparation may activate tryptophan degradation resulting in higher levels of metabolites in serum than in plasma.
文摘The influence of exogenic hormones (indole-3-acetic acid (IAA), abscisic acid (ABA) and kinetin) on defense reaction of wheat (Triticum aestivum L.) calli to the bunt agent Tilletia caries (D.C.) Tul. & C. Tul. was studied. ABA and kinetin induced the oxalate oxidase activity, increased the Н2О2 level, decreased germination of fungi teliospores and induced on calli the occurrence of dense sites non-infected by pathogen. On the contrary, IAA led to the decrease of oxalate oxidase activity, loosening of calli and increase germination of bunt agent teliospores and growth of fungi mycelium, besides stimulated rhizoids formation of wheat calli. Probably, the accumulation of Н2О2 in wheat calli under the influence of kinetin and ABA connected with activity of oxalate oxidase is one of the factors increasing defense reaction of wheat to bunt agent.
基金supported by the National Natural Science Foundation of China(Nos.51263010,51272096)Jiangxi Provincial Department of Education(No.GJJ11590)Natural Science Foundation of Jiangxi Province(No.2010GZH0041)
文摘A novel graphene oxide （GO） doped poly（hydroxymethylated-3,4-ethylenedioxythiophene） （PEDOTM） film has been achieved via one-step co-electrodeposition and utilized for electrochemical studies of indole-3-acetic acid （IAA）. The incorporation of GO into PEDOTM film facilitated the electrocatalytic activity and exhibited a favorable interaction between the PEDOTM/GO film and the phytohormone during the oxidation of IAA. Under optimized conditions, differential pulse voltammetry and square wave voltammetry were used for the quantitative analysis of IAA, respectively, each exhibiting a wide linearity range from 0.6 μmol L-1 to 10 μmol L-1 and 0.05 μmol L-1 to 40 μmol L-1, good sensitivity with a low detection Iimit of 0.087 μmol L-1 and 0.033μmol L T, respectively, as well as good stability. With the notable advantages of a green, sensitive method, expeditious response and facile operation, the as-prepared PEDOTM/GO organic-inorganic composite film provides a promising platform for electrochemical studies of IAA.
