Polyamines(PAs)and ethylene are involved in the modulation of plant growth and development.However,their roles in fruit-set,especially in exogenous gibberellin(GA_(3))-induced grape parthenocarpic berries,and the rela...Polyamines(PAs)and ethylene are involved in the modulation of plant growth and development.However,their roles in fruit-set,especially in exogenous gibberellin(GA_(3))-induced grape parthenocarpic berries,and the related competitive action mode are poorly understood.For this,we,here performed their content determination,bioinformatics and expression pattern analysis of genes to identify the key ones in the competitive network of polyamines metabolic and ethylene biosynthesis(PMEB)pathways.The content of putrescine(Put)significantly increased;while 1-aminocyclopropanecarboxylic acid(ACC)sharply decreased during the fruit-set process of GA_(3)-induced grape parthenocarpic seedless berries.Totally,twenty-five genes in PMEB pathways,including 20 polyamines metabolic(PM)genes and 5 ethylene biosynthesis(EB)ones were identified in grape,of which 8 PM and 2 EB genes possessed the motifs responsive to phytohormone GA.The expression levels of most PMEB genes kept changing during grape fruit-set generating a competitive action mode of GA_(3)-mediated two metabolic fluxes toward PAs and ethylene synthesis.Exogenous GA_(3)might enhance grape fruit-set of parthenocarpic berries via up-regulation of VvSAMS4,VvSAMDC1/2,VvODC1,VvSPDS1,and VvPAO1 to promote PAs accumulation,whereby repressing the ethylene synthesis by down-regulation of VvACS1 and VvACO_(2).Our findings provide novel insights into GA_(3)-mediated competitive inhibition of ethylene by PAs to promote the fruit-set of parthenocarpic berries in grape,which has important implications for molecular breeding of seedless grape with high fruit-setting rate.展开更多
Polyamines(putrescine,spermidine,and spermine)are aliphatic compounds ubiquitous in prokaryotes and eukaryotes.Positively charged polyamines bind to negatively charged macromolecules,such as nucleic acids and acidic p...Polyamines(putrescine,spermidine,and spermine)are aliphatic compounds ubiquitous in prokaryotes and eukaryotes.Positively charged polyamines bind to negatively charged macromolecules,such as nucleic acids and acidic phospholipids,and are involved in physiological activities including cell proliferation,differentiation,apoptosis and gene regulation.Intracellular polyamine levels are regulated by biosynthesis,catabolism and transport.Polyamines in the body originate from two primary sources:dietary intake and intestinal microbial metabolism.These polyamines are then transported into the bloodstream,through which they are distributed to various tissues and organs to exert their biological functions.Polyamines synthesized by intestinal microorganisms serve dual critical roles.First,they are essential for maintaining polyamine concentrations within the digestive tract.Second,through transcriptional and post-transcriptional mechanisms,these microbial-derived polyamines modulate the expression of genes governing key processes in intestinal epithelial cells-including proliferation,migration,apoptosis,and cell-cell interactions.Collectively,these regulatory effects help maintain intestinal epithelial homeostasis and ensure the integrity of the gut barrier.In addition,polyamines interact with the gut microbiota to maintain intestinal homeostasis by promoting microbial growth,biofilm formation,swarming,and endocytosis vesicle production,etc.Supplementation with polyamines has been demonstrated to be important in regulating host intestinal microbial composition,enhancing nutrient absorption,and improving metabolism and immunity.In this review,we will focus on recent advances in the study of polyamine metabolism and transport in intestinal microbes and intestinal epithelial cells.We then summarize the scientific understanding of their roles in intestinal homeostasis,exploring the advances in cellular and molecular mechanisms of polyamines and their potential clinical applications,and providing a rationale for polyamine metabolism as an important target for the treatment of intestinal-based diseases.展开更多
The acetylpolyamine oxidase(APAO),spermine oxidase(SMO),and spermidine/spermine N1-acetyltransferase(SSAT)are pivotal enzymes in polyamine metabolism,exerting direct influence on polyamine homeostasis regulation.Dysfu...The acetylpolyamine oxidase(APAO),spermine oxidase(SMO),and spermidine/spermine N1-acetyltransferase(SSAT)are pivotal enzymes in polyamine metabolism,exerting direct influence on polyamine homeostasis regulation.Dysfunctions in these enzymes are intricately linked to inflammatory diseases and cancers.Establishing their three-dimensional structures is essential for exploring enzymatic catalytic mechanisms and designing inhibitors at the atomic level.This article primarily assesses the precision of AlphaFold2 and molecular dynamics simulations in determining the three-dimensional structures of these enzymes,utilizing protein conformation rationality assessment,residue correlation matrix,and other techniques.This provides robust models for subsequent polyamine catabolic metabolism calculations and offers valuable insights for modeling proteins that have yet to acquire crystal structures.展开更多
Macrocyclic polyamines are excellent chelating agents with the advantage of forming highly stable complexes.They offer the flexibility to adjust the coordination environment through functionalization.making them valua...Macrocyclic polyamines are excellent chelating agents with the advantage of forming highly stable complexes.They offer the flexibility to adjust the coordination environment through functionalization.making them valuable in numerous applications owing to their unique chemical and biological characteristics.This review summarizes the use of macrocyclic polyamines as carriers and molecular platforms of targeted drugs for medical applications.The significance and innovative design of these original approaches are dissected from the unique perspective of diverse mechanisms,such as iron depletion,metallo-β-lactamases inhibitors,intracellular ATP depletion,non-viral gene vector,DNA/RNA syntheses inhibitors and theranostics agent.Of interest are the metal complex of macrocyclic polyamines,which is usually a double-edged sword as dealing with endogenous macromolecular targets,especially DNA.These excellent cases will help to understand the typical mechanism in drug design based on macrocyclic polyamines,and achieve actual applications in medicine.展开更多
[Objective]The aim of this study was to understand the role of polyamine oxidative degradation in the process of lettuce seed germination. [Method]After lettuce seed soaking treatments with aminoguanidine （AG,a speci...[Objective]The aim of this study was to understand the role of polyamine oxidative degradation in the process of lettuce seed germination. [Method]After lettuce seed soaking treatments with aminoguanidine （AG,a specific inhibitor of polyamine oxidases）,seed germination rate,activities of polyamine oxidase （PAO） and diamine oxidase （DAO）,change of endogenous polyamine and H2O2 content were determined. [Result]Compared with the control,AG treatment strongly inhibited the seed germination,which also had an extremely significant difference in seed germination rate after incubation for 12 h. During the seed germination,activities of PAO and DAO significantly changed,while their activities firstly increased and then decreased,then DAO and PAO reached peaks at 24 h and 48 h respectively. AG treatment was strongly inhibitory for activities of DAO and PAO,whose activities even disappeared after incubation with AG for 24 h and 36 h. During the seed germination,endogenous Put reduced sharply in the first 24 h,then reduced slowly in 24-60 h,while Spd decreased slowly in the early stage of germination,and then sharply declined after 48 h. However,Spm content was low but slightly increased,and the total polyamine gradually decreased. AG treatment could significantly increase endogenous polyamines,especially Put and Spd contents. During the seed germination,H2O2 content gradually increased,and had a peak from 36 to 48 h,then kept a high level at last. AG treatment could significantly reduce H2O2 content. [Conclusion]During the seed germination,the changes of endogenous polyamine and H2O2 content correspond with the changes of PAO and DAO activities,which indicate that there is an active polyamine metabolism of oxidative degradation during the lettuce seed germination.展开更多
Plant growth rate (GR), contents of free polyamines (fPAs) and bound polyamines (bPAs) and activities of some key enzymes involved in polyamine (PA) metabolism in the roots of two barley (Hordeum valgare L.) cultivars...Plant growth rate (GR), contents of free polyamines (fPAs) and bound polyamines (bPAs) and activities of some key enzymes involved in polyamine (PA) metabolism in the roots of two barley (Hordeum valgare L.) cultivars differing in salt sensitivity were investigated with 0-300 mmol/L NaCl treatments. With 0-200 mmol/L NaCl treatments, activities of arginine decarboxylase (ADC) and transglutaminase (TGase) and PA oxidase (PAO) in the roots of barley seedlings all increased, while TGase and PAO activities decreased slightly at 300 mmol/L NaCl. As a result, free Put (fPut) content increased continuously with increasing concentrations of NaCl, while levels of free Spd (fSpd) and an unknown PA (fPAx) and bPAs (bPut, bSpd and bPAx), as well as (fSpd + fPAx)/fPut ratio rose at 50-200 mmol/L NaCl and reduced at 300 mmol/L NaCl. However, no significant change in the tetra-amine spermine (Spin) content was observed. Statistical analysis showed that GR was very significantly positively correlated with (fSpd + fPAx)/fPut ratios and the contents of bPAs, whereas a significant inverse correlation existed between GR and the ratios of fPA contents to bPA levels. These results showed that, under salt stress, the balance between fSpd, fPAx and fPut levels and an equipoise between fPA and bPA contents in roots were important to salt tolerance of barley seedlings.展开更多
[Objective]The research aimed to probe into the mechanism of polyamine enhancing the tolerance of plants to drought stress and provide theoretical basis for application of polyamine in process of maize drought resista...[Objective]The research aimed to probe into the mechanism of polyamine enhancing the tolerance of plants to drought stress and provide theoretical basis for application of polyamine in process of maize drought resistance. [Method]With PEG-6000 simulating natural drought,the change in content of soluble protein and relative water content were investigated in seedling leaves of two maize cultivars,Nongda 108 and Yedan 13 under osmotic stress with exogenous Spd treatment. [Result]On the 7th day,leaf relative water content and the content of soluble protein decreased more significantly in leaves of Yedan 13 （drought-sensitive） than in Nongda 108 （drought-tolerant）. Exogenous Spd treatment not only obviously inhibited the decrease of leaf relative water content,but also increased the content of soluble protein. [Conclusion]Exogenous Spd treatment could enhance the tolerance of maize seedlings to osmotic stress,via improving the content of soluble protein in seedling leaves.展开更多
The seeds of barley Hordeum vulgare L. cv. Jian 4) were soaked with 0.1 mmol/L putrescine (Put) and 0.5 mmol/L spermidine (Spd), and then the seedlings were treated with 200 mmol/L NaCl. The growth rate (GR), dry matt...The seeds of barley Hordeum vulgare L. cv. Jian 4) were soaked with 0.1 mmol/L putrescine (Put) and 0.5 mmol/L spermidine (Spd), and then the seedlings were treated with 200 mmol/L NaCl. The growth rate (GR), dry matter accumulation, distribution of ions, the amount of polyamines (PAs) bound to tonoplast proteins as well as lipid composition and the activity of tonoplast vesicles isolated from roots were investigated. The results showed that soaking with Put or Spd could retard salt injury, promote GR and dry matter accumulation, and increase K+/Na+ in the roots. Compared with NaCl_treated plants, phospholipid content in root tonoplast rose by soaking with Put and Spd, while the level of galactose in lipids was decreased. Moreover, the ratio in noncovalently conjugated PA contents of (Spd+PAx (an unknown PA)) to (Put+Dap (diaminopropane)), and the total contents of covalently and noncovalently conjugated PAs were all increased. Statistical analysis indicated that the ratio of (Spd+PAx) to (Put+Dap) was significantly and positively correlated with the activities of membrane associated enzymes H+_ATPase and H+_PPase.展开更多
Salt stress is one of the worldwide abiotic stresses resulting in growth re- duction, chlorosis, wilting, and plant death. These exhibitions might result from men- tal toxicity and osmotic stress induced by salt. The ...Salt stress is one of the worldwide abiotic stresses resulting in growth re- duction, chlorosis, wilting, and plant death. These exhibitions might result from men- tal toxicity and osmotic stress induced by salt. The two aspects of stress would af- fect vital metabolic pathways, reactive oxygen species scavenging system, lipid per- oxidation and photosynthetic apparatus. Thus, exploring ways to improve crop pro- ductivity or alleviate harmful effects under salt is one of the major areas of concern. Polyamines are aliphatic nitrogen organic cations which are implicated in a wide range of plant physiological processes such as morphogenesis, flower differentiation and initiation, they also play a role in biotic or abiotic stress responses. At the physiological level, polyamines modify the activities of many enzymes included in salt stress response and can bond to photosynthetic apparatus, thus changing the photosynthetic efficiency. At molecular level, polyamines can modify expressions of the polyamine-related genes directly or indirectly. Significant researches had been done to understand the effects of polyamines on plant salt resistance, but several questions still need to be answered. The present review is focused specifically on the effects of polyamines on physiological and molecular changes in plants under salt stress.展开更多
[Objective] This study aimed to investigate the effect of potyamine priming on physiological and biochemical variations of Lolium perenne embryos and seed germination. [Method] With annual Lolium perenne （Diamond T a...[Objective] This study aimed to investigate the effect of potyamine priming on physiological and biochemical variations of Lolium perenne embryos and seed germination. [Method] With annual Lolium perenne （Diamond T and Grazing-8000） as experimental materials, after priming with 0.5 mmol/L putrescine （Put）, spermidine （Spd） and spermine （Spm） for 24 h and chilling imbibition at 5 ℃ for 12, 24, 36 and 48 h, the effect of Put, Spd and Spm priming on chilling tolerance and germination ability of annual Lolium perenne seeds during imbibition was investigated. [Result] Put, Spd and Spm priming improved the activities of peroxidase （POD）, catalase （CAT）, superoxide dismutase （SOD） and ascorbate peroxidase （APX） and content of soluble protein content under low temperature stress, significantly in-creased the germination rate, and shortened the average germination duration. After chilling imbibition for 48 h, compared with the control, the average germination rate of annual Lolium perenne seeds was improved by 15.5% and 12.0% after Put, Spd and Spm priming, and the average germination duration was shortened by 1.21 and 1.14 d. During seed imbibition, the chilling tolerance of Grazing-8000 was stronger than that of Diamond T. Overall, Put, Spd and Spm treatment could increase the chilling tolerance of annual Lolium perenne seeds during imbibition, and improve the germination ability of seeds under low temperature stress. [Conclusion] Results of this study provided theoretical basis for the application of seed priming technology in the production of annual ryegrass.展开更多
The effects of osmotic stress on the ATPase activity, the contents of —SH group and conjugated polyamines in mitochondrial membrane from wheat seedling [Triticum aestivum L. cv. Yumai No.18(drought-tolerant) and cv. ...The effects of osmotic stress on the ATPase activity, the contents of —SH group and conjugated polyamines in mitochondrial membrane from wheat seedling [Triticum aestivum L. cv. Yumai No.18(drought-tolerant) and cv. Yumai No.9(drought-sensitive)] roots were investigated. The results showed that ATPase activity and —SH group content decreased with polyethylene glycol(PEG) 6000(-0.55 MPa) treatment for 7 d, in concert with the decrease of the ratio of noncovalently conjugated spermidine(NCC-Spd)/noncovalently conjugated putrescine(NCC-Put) and increase of the covalently conjugated putrescine(CC-Put). Osmotic stress injury to Yangmai No.9 seedlings was alleviated greatly with 1 mmol/L exogenous spermidine(Spd), in concert with marked increases of the ratio of NCC-Spd/NCC-Put, —SH group contents and ATPase activity in mitochondrial membrane. Under osmotic stress, the concomitant treatment of Yumai No.18 seedlings with methylglyoxyl bis(guanylhydrazone) (MGBG), an inhibitor of S-adenosyl methionine decarboxylase(SAMDC), and phenanthrolin (o-Phen), an inhibitor of transglutaminase(TGase), caused a significant decrease of the ratio of NCC-Spd / NCC-Put, CC-Put contents, respectively, in concert with the marked decreases of ATPase activity, —SH group content and its tolerance to osmotic stress. All the results above suggested that osmotic stress tolerance of wheat seedlings was associated with the ATPase activity, the contents of —SH group, NCC-Spd and CC-Put in mitochondrial membrane.展开更多
Astragalus membranaceus(Radix Astragali, RA) and Atractylodes macrocephala(Rhizoma Atractylodis Macrocephalae, RAM) are often used to treat gastrointestinal diseases. In the present study, we determined the effects of...Astragalus membranaceus(Radix Astragali, RA) and Atractylodes macrocephala(Rhizoma Atractylodis Macrocephalae, RAM) are often used to treat gastrointestinal diseases. In the present study, we determined the effects of polysaccharides extracts from these two herbs on IEC-6 cell migration and explored the potential underlying mechanisms. A migration model with IEC-6 cells was induced using a single-edged razor blade along the diameter of cell layers in six-well polystyrene plates. The cells were grown in control--media or media containing spermidine(5 μmol·L^(-1), SPD), alpha-difluoromethylornithine(2.5 mmol·L^(-1), DFMO), 4-Aminopyridine-(40 μ-mol·L^(-1), 4-AP), the polysaccharide extracts of RA or RAM(50, 100, or 200 mg·L^(-1)), DFMO plus SPD, or DFMO plus polysaccharide extracts of RA or RAM for 12 or 24 h. Next, cytosolic free Ca^(2+)([Ca^(2+)]cyt) was measured using laser confocal microscopy, and cellular polyamine content was quantified with HPLC. Kv1.1 mRNA expression was assessed using RT-qPCR and Kv1.1 and RhoA protein expressions were measured with Western blotting analysis. A cell migration assay was carried out using Image-Pro Plus software. In addition, GC-MS was introduced to analyze the monosaccharide composition of both polysaccharide extracts. The resutls showed that treatment with polysaccharide extracts of RA or RAM significantly increased cellular polyamine content, elevated [Ca^(2+)]cyt and accelerated migration of IEC-6 cells, compared with the controls(P < 0.01). Polysaccharide extracts not only reversed the inhibitory effects of DFMO on cellular polyamine content and [Ca^(2+)]cyt, but also restored IEC-6 cell migration to control level(P < 0.01 or < 0.05). Kv1.1 mRNA and protein expressions were increased(P < 0.05) after polysaccharide extract treatment in polyamine-deficient IEC-6 cells and RhoA protein expression was increased. Molar ratios of D-ribose, D-arabinose, L-rhamnose, D-mannose, D-glucose, and D-galactose was 1.0:14.1:0.3:19.9:181.3:6.3 in RA and 1.0:4.3:0.1:5.7:2.8:2.2 in RAM. In conclusion, treatment with RA and RAM polysaccharide extracts stimulated migration of intestinal epithelial cells via a polyamine-Kv1.1 channel activated signaling pathway, which facilitated intestinal injury healing.展开更多
Hydrogen peroxide （H2O2） is an important signaling molecule in ethylene-induced stomatal closure in Arabidopsis thaliana. Early studies on the sources of H2O2 mainly focused on NADPH oxidases and cell-wall peroxidas...Hydrogen peroxide （H2O2） is an important signaling molecule in ethylene-induced stomatal closure in Arabidopsis thaliana. Early studies on the sources of H2O2 mainly focused on NADPH oxidases and cell-wall peroxidases. Here, we report the involvement of polyamine oxidases （PAOs） in ethylene-induced H2O2 production in guard cells. In Arabidopsis epidermal peels, application of PAO inhibitors caused the failure of ethylene to induce H2O2 production and stomatal closure. Results of quantitative RT-PCR analysis and pharmacological experiments showed that AtPAO2 and AtPAO4 transcripts and activities of PAOs were both induced by ethylene. In transgenic Arabidopsis plants over-expressing AtPAO2 and AtPAO4, stomatal movement was more sensitive to ethylene treatment and H2O2 production was also significantly induced. The increased H2O2 production in the transgenic lines compared to the wild-type plants suggests that AtPAO2 and AtPAO4 probably are involved in ethylene-induced H2O2 production. Several factors which induce stomatal closure such as dehydration and high salinity all enhanced the expression of AtPAO2 and AtPAO4 to different degrees. Moreover, GFP- AtPAOs fusion protein localized in the nucleus, cytoplasm, and cell wall of the guard cells. Therefore, our results strongly indicated that PAO is a source of H2O2 generation in Arabidopsis guard cells and plays crucial roles in stomatal movement.展开更多
The mechanism of melatonin(MT)induced chilling tolerance in harvested cucumber fruit was investigated at commercial maturity.In this study,cucumber fruits were treated with 100μmol L^(-1) MT at 4℃ and 90% relative h...The mechanism of melatonin(MT)induced chilling tolerance in harvested cucumber fruit was investigated at commercial maturity.In this study,cucumber fruits were treated with 100μmol L^(-1) MT at 4℃ and 90% relative humidity for 15 d of storage.In comparison with the control,cucumber treatment with MT resulted in reduced chilling injury(CI),decreased electrolyte leakage and enhanced firmness.The fruits treated with MT showed higher chlorophyll contents in storage conditions with suppressed chlorophyllase enzyme activity.MT treatment increased arginine decarboxylase(ADC)and ornithine decarboxylase(ODC)enzyme activities.Moreover,enhanced expression of the Cucumis sativus ADC(CsADC)and C.sativus ODC(CsODC)genes resulted in the accumulation of polyamine contents.Similarly,proline levels exhibited higher levels among treated fruits.Meanwhile,the proline synthesizing enzymes △1-pyrroline-5-carboxylate syntheses(P5CS)and ornithine aminotransferase(OAT)were significantly increased,while a catabolic enzyme of proline dehydrogenase(PDH)activity was inhibited by treatment.In addition,MT induced expression of C.sativus OAT(CsOAT)and C.sativus P5CS(CsP5CS)genes.Cucumber fruits treated with MT also exhibited higher γ-aminobutyric acid(GABA)content by enhanced GABA transaminase(GABA-T)and glutamate decarboxylase(GAD)enzyme activities and a higher C.sativus GAD(CsGAD)gene expression.To sum up,the results show that MT treatment enhanced chilling tolerance,which was associated with the regulation of polyamines,as well as proline and γ-aminobutyric acid.展开更多
The free putrescine （Put） content, the hydrogen peroxide （H202） content and the polyamine oxidase （PAO） activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang （PYTC） were significantly increased, an...The free putrescine （Put） content, the hydrogen peroxide （H202） content and the polyamine oxidase （PAO） activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang （PYTC） were significantly increased, and reached its peak at 1, 2 and 6 h, respectively, under cadmium treatment. The free spermine （Spin） and spermidine （Spd） contents were dramatically decreased, and reached the minimum value at 4-6 h, then remained relatively stable. The change in total free polyammes （PAs） content was consistent with that of free Put. The number of root dead cells was gradually increased after treatment for 24 h, and the typical characteristics of programmed cell death （PCD） were displayed at 48 h. Throughout the Cd treatment process, changes in PAs metabolism appeared to be prior to cell death increase, and the H2O2 content was always maintained at a high level. These results indicated that polyamines could initiate cell death by generating H2O2 in roots of Malus hupehensis Rehd. under CdSO4 stress.展开更多
Drought is a multifaceted stress condition that inhibits crop growth.Seed germination is one of the critical and sensitive stages of plants,and its process is inhibited or even entirely prevented by drought.Polyamines...Drought is a multifaceted stress condition that inhibits crop growth.Seed germination is one of the critical and sensitive stages of plants,and its process is inhibited or even entirely prevented by drought.Polyamines(PAs)are closely associ-ated with plant resistance to drought stress and seed germination.However,little is known about the effect of PA on the seed germination of wheat under drought stress.This study investigated the involvement of PAs in regulating wheat seed germination under drought stress.Six wheat genotypes differing in drought resistance were used,and endogenous PA levels were measured during seed germination under different water treatments.In addition,external PAwas used for seed soaking and the variation of hormones,total soluble sugar and starch were measured during the seed germination under different water treatments.These results indicated that the free spermidine(Spd)accumulation in seeds during the seed germination period favored wheat seed germination under drought stress;however,the free putrescine(Put)accumulation in seeds during the seed germination period may work against wheat seed germination under drought stress.In addition,seed soaking in Spd and spermine(Spm)significantly relieved the inhibition of seed germination by drought stress;howev-er,soaking seeds in Put had no significant effect on seed germination under drought.External Spd and Spm significantly increased the endogenous indole-3-acetic acid(IAA),zeatin(Z)+zeatin riboside(ZR),abscisic acid(ABA),and gibberellins(GA)contents in seeds and accelerated the seed starch degradation and increased the concentration of soluble sugars in seeds during seed germination.This may promote wheat seed germination under drought stress.In conclusion,free Spd and Put are key factors for regulating wheat seed germination under drought stress and the effects of Spd and Put on seed germination under drought notably related to hormones and starch metabolism.展开更多
The activities of the catalytic hydrolysis of phosphate diester （BNPP） [bis（p-nitrophenyl）phosphate diester] and plasmid DNA （pUC 18） by mononuclear macrocyclic polyamine metal complexes have been investigated i...The activities of the catalytic hydrolysis of phosphate diester （BNPP） [bis（p-nitrophenyl）phosphate diester] and plasmid DNA （pUC 18） by mononuclear macrocyclic polyamine metal complexes have been investigated in this paper. The results showed that the highest activity in hydrolysis of BNPP was obtained with le--Zn（II） complex （composed of lipophilic group） as catalyst. The hydrolysis rate enhancement is up to 3.64 × 10^4 fold. These metal complexes could effectively promote the cleavage of plasmid DNA （pUC18） at physiological conditions.展开更多
Polyamines(PAs) are important endogenous plant growth regulators responding to environmental stress and mediating many physiological processes including grain filling in cereals.This study investigated whether PAs med...Polyamines(PAs) are important endogenous plant growth regulators responding to environmental stress and mediating many physiological processes including grain filling in cereals.This study investigated whether PAs mediate the effect of post-anthesis soil drying on starch granule size distribution,starch content,and weight of superior and inferior kernels of wheat(Triticum aestivum L.).Two wheat cultivars were grown in pots.Three treatments,well-watered(WW),moderate soil drying(MD) and severe soil drying(SD),were imposed from 9 days post-anthesis until maturity.PA levels in kernels and small,medium and large granules were measured.The results showed that superior kernels had much higher free spermidine(Spd) and free spermine(Spm) concentrations,larger volumes of medium starch granules,and smaller-sized large granules than did inferior kernels under all the treatments.Compared to WW,MD significantly increased the concentrations of free Spd and free Spm,activities of soluble starch synthase and granule-bound starch synthase,volume of medium granules,and starch content and kernel weight of inferior kernels,and decreased the size of large granules.SD produced the opposite effect.Application of Spd or Spm to spikes produced effects similar to those of MD,and application of an inhibitor of Spd and Spm synthesis produced effects similar to those of SD.These results suggest that PAs mediate the effect of post-anthesis soil drying on starch biosynthesis in wheat kernels by regulating key enzymes in starch synthesis and that elevated PA levels under MD increase the volume of medium granules and kernel weight of inferior kernels.展开更多
The relationship between gross domestic pro- duct (GDP) and dietary profile, with a focus on polyamine intake, was investigated in 35 Asian countries. Data on food supply, GDP, and health condition were collected from...The relationship between gross domestic pro- duct (GDP) and dietary profile, with a focus on polyamine intake, was investigated in 35 Asian countries. Data on food supply, GDP, and health condition were collected from databases of the United Nations, the International Monetary Fund, and the World Health Organization, respectively. The amount of polyamine intake from food was estimated using polyamine concentrations listed in published sources. The amounts of putrescine, spermidine, spermine, and total polyamines in 1000 kcal of food in Asian countries were 39.07 ± 17.98, 33.74 ± 14.35, 14.05 ± 6.60 and 86.85 ± 33.96 μmol/1000 kcal, respectively. Putrescine, spermidine, and spermine constituted 44, 39, and 17% of total polyamine, respectively. Vegetables contributed the largest amount of both putrescine and spermidine and the second largest amount of spermine (45.5%, 62.2% and 27.2% of total putrescine, spermidine, and spermine, respectively). Meat was the richest source of spermine and contributed the greatest amount (50%) of this polyamine. We showed a significant positive association between GDP and the amount of polyamine per 1000 kcal of food. Lifespan was associated with both GDP and the amount of polyamine per energy quotient of food. As several basic research studies have shown that polyamines help prolong longevity, it follows that polyamines may have a role in determining the lifespan of humans.展开更多
<abstract>Aim: To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis. Methods: Male golden hamsters of 7-week-o...<abstract>Aim: To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis. Methods: Male golden hamsters of 7-week-old were kept under a light and dark cycle of 14 h and 10 h for 1 week to stimulate maximally the gonadal function. DES was injected subcutaneously at doses of 0.01 mg·kg-1·day-1, 0.1 mg·kg-1·day-1 and 1 mg·kg-1·day-1 for one week. Results: DES treatment caused a significant decrease in the weight of epididymis. The activity of epididymal ornithine decar boxylase (ODC) increased 1 day after DES treatment, kept at a high level for 4 days and then decreased to nearly normal level at day 7. The activity of spermidine/spermine N1-acetyltransferase (SSAT) also increased transiently after DES treatment. The contents of putrescine, spermidine, spermine and N1-acetylspermidine were increased 1 day -4 days after DES treatment and restored to normal at day 7. All these changes showed a marked difference between the caput and the cauda. Conclusion: The polyamine biosynthesis in the hamster epididymis can be affected by DES, a xenoestrogen. DES may probably affect polyamine metabolism in the epididymis by regulating the rate-limiting enzymes involved in the polyamine biosynthesis.展开更多
基金supported by grants from Jiangsu province seed industry revitalization of the leading project(JBGS[2021]086)the National Natural Science Funds(31972373,32272647,32202433)+1 种基金the Provincial Natural Science Foundation of Jiangsu(BK20200541)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD),and Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_0754,SJCX23-0209).
文摘Polyamines(PAs)and ethylene are involved in the modulation of plant growth and development.However,their roles in fruit-set,especially in exogenous gibberellin(GA_(3))-induced grape parthenocarpic berries,and the related competitive action mode are poorly understood.For this,we,here performed their content determination,bioinformatics and expression pattern analysis of genes to identify the key ones in the competitive network of polyamines metabolic and ethylene biosynthesis(PMEB)pathways.The content of putrescine(Put)significantly increased;while 1-aminocyclopropanecarboxylic acid(ACC)sharply decreased during the fruit-set process of GA_(3)-induced grape parthenocarpic seedless berries.Totally,twenty-five genes in PMEB pathways,including 20 polyamines metabolic(PM)genes and 5 ethylene biosynthesis(EB)ones were identified in grape,of which 8 PM and 2 EB genes possessed the motifs responsive to phytohormone GA.The expression levels of most PMEB genes kept changing during grape fruit-set generating a competitive action mode of GA_(3)-mediated two metabolic fluxes toward PAs and ethylene synthesis.Exogenous GA_(3)might enhance grape fruit-set of parthenocarpic berries via up-regulation of VvSAMS4,VvSAMDC1/2,VvODC1,VvSPDS1,and VvPAO1 to promote PAs accumulation,whereby repressing the ethylene synthesis by down-regulation of VvACS1 and VvACO_(2).Our findings provide novel insights into GA_(3)-mediated competitive inhibition of ethylene by PAs to promote the fruit-set of parthenocarpic berries in grape,which has important implications for molecular breeding of seedless grape with high fruit-setting rate.
基金supported by projects from the Xinjiang Production and Construction Corps Major Science and Technology"Revealing the List and Taking Command"Project(2023AB078)the Ministry of Science and Technology High-end Foreign Expert Project(G2023014066L)the Xinjiang Production and Construction Corps Agricultural Science and Technology Innovation Engineering Special Project(NCG202232).
文摘Polyamines(putrescine,spermidine,and spermine)are aliphatic compounds ubiquitous in prokaryotes and eukaryotes.Positively charged polyamines bind to negatively charged macromolecules,such as nucleic acids and acidic phospholipids,and are involved in physiological activities including cell proliferation,differentiation,apoptosis and gene regulation.Intracellular polyamine levels are regulated by biosynthesis,catabolism and transport.Polyamines in the body originate from two primary sources:dietary intake and intestinal microbial metabolism.These polyamines are then transported into the bloodstream,through which they are distributed to various tissues and organs to exert their biological functions.Polyamines synthesized by intestinal microorganisms serve dual critical roles.First,they are essential for maintaining polyamine concentrations within the digestive tract.Second,through transcriptional and post-transcriptional mechanisms,these microbial-derived polyamines modulate the expression of genes governing key processes in intestinal epithelial cells-including proliferation,migration,apoptosis,and cell-cell interactions.Collectively,these regulatory effects help maintain intestinal epithelial homeostasis and ensure the integrity of the gut barrier.In addition,polyamines interact with the gut microbiota to maintain intestinal homeostasis by promoting microbial growth,biofilm formation,swarming,and endocytosis vesicle production,etc.Supplementation with polyamines has been demonstrated to be important in regulating host intestinal microbial composition,enhancing nutrient absorption,and improving metabolism and immunity.In this review,we will focus on recent advances in the study of polyamine metabolism and transport in intestinal microbes and intestinal epithelial cells.We then summarize the scientific understanding of their roles in intestinal homeostasis,exploring the advances in cellular and molecular mechanisms of polyamines and their potential clinical applications,and providing a rationale for polyamine metabolism as an important target for the treatment of intestinal-based diseases.
基金National Natural Science Foundation of China(22073023)Natural Science Foundation of Henan Province(242300421134)+1 种基金the Young Backbone Teacher in Colleges and Universities of Henan Province(2021GGJS020)Foundation of State Key Laboratory of Antiviral Drugs。
文摘The acetylpolyamine oxidase(APAO),spermine oxidase(SMO),and spermidine/spermine N1-acetyltransferase(SSAT)are pivotal enzymes in polyamine metabolism,exerting direct influence on polyamine homeostasis regulation.Dysfunctions in these enzymes are intricately linked to inflammatory diseases and cancers.Establishing their three-dimensional structures is essential for exploring enzymatic catalytic mechanisms and designing inhibitors at the atomic level.This article primarily assesses the precision of AlphaFold2 and molecular dynamics simulations in determining the three-dimensional structures of these enzymes,utilizing protein conformation rationality assessment,residue correlation matrix,and other techniques.This provides robust models for subsequent polyamine catabolic metabolism calculations and offers valuable insights for modeling proteins that have yet to acquire crystal structures.
基金National Natural Science Foundation of China(Nos.22177011,21977012,and 21672021)the Joint Project of BRCBC(Biomedical Translational Engineering Research Center of BUCT-CJFH)(No.XK2020-06).
文摘Macrocyclic polyamines are excellent chelating agents with the advantage of forming highly stable complexes.They offer the flexibility to adjust the coordination environment through functionalization.making them valuable in numerous applications owing to their unique chemical and biological characteristics.This review summarizes the use of macrocyclic polyamines as carriers and molecular platforms of targeted drugs for medical applications.The significance and innovative design of these original approaches are dissected from the unique perspective of diverse mechanisms,such as iron depletion,metallo-β-lactamases inhibitors,intracellular ATP depletion,non-viral gene vector,DNA/RNA syntheses inhibitors and theranostics agent.Of interest are the metal complex of macrocyclic polyamines,which is usually a double-edged sword as dealing with endogenous macromolecular targets,especially DNA.These excellent cases will help to understand the typical mechanism in drug design based on macrocyclic polyamines,and achieve actual applications in medicine.
基金Supported by Doctorate Fund of Suzhou University (13120740)~~
文摘[Objective]The aim of this study was to understand the role of polyamine oxidative degradation in the process of lettuce seed germination. [Method]After lettuce seed soaking treatments with aminoguanidine （AG,a specific inhibitor of polyamine oxidases）,seed germination rate,activities of polyamine oxidase （PAO） and diamine oxidase （DAO）,change of endogenous polyamine and H2O2 content were determined. [Result]Compared with the control,AG treatment strongly inhibited the seed germination,which also had an extremely significant difference in seed germination rate after incubation for 12 h. During the seed germination,activities of PAO and DAO significantly changed,while their activities firstly increased and then decreased,then DAO and PAO reached peaks at 24 h and 48 h respectively. AG treatment was strongly inhibitory for activities of DAO and PAO,whose activities even disappeared after incubation with AG for 24 h and 36 h. During the seed germination,endogenous Put reduced sharply in the first 24 h,then reduced slowly in 24-60 h,while Spd decreased slowly in the early stage of germination,and then sharply declined after 48 h. However,Spm content was low but slightly increased,and the total polyamine gradually decreased. AG treatment could significantly increase endogenous polyamines,especially Put and Spd contents. During the seed germination,H2O2 content gradually increased,and had a peak from 36 to 48 h,then kept a high level at last. AG treatment could significantly reduce H2O2 content. [Conclusion]During the seed germination,the changes of endogenous polyamine and H2O2 content correspond with the changes of PAO and DAO activities,which indicate that there is an active polyamine metabolism of oxidative degradation during the lettuce seed germination.
文摘Plant growth rate (GR), contents of free polyamines (fPAs) and bound polyamines (bPAs) and activities of some key enzymes involved in polyamine (PA) metabolism in the roots of two barley (Hordeum valgare L.) cultivars differing in salt sensitivity were investigated with 0-300 mmol/L NaCl treatments. With 0-200 mmol/L NaCl treatments, activities of arginine decarboxylase (ADC) and transglutaminase (TGase) and PA oxidase (PAO) in the roots of barley seedlings all increased, while TGase and PAO activities decreased slightly at 300 mmol/L NaCl. As a result, free Put (fPut) content increased continuously with increasing concentrations of NaCl, while levels of free Spd (fSpd) and an unknown PA (fPAx) and bPAs (bPut, bSpd and bPAx), as well as (fSpd + fPAx)/fPut ratio rose at 50-200 mmol/L NaCl and reduced at 300 mmol/L NaCl. However, no significant change in the tetra-amine spermine (Spin) content was observed. Statistical analysis showed that GR was very significantly positively correlated with (fSpd + fPAx)/fPut ratios and the contents of bPAs, whereas a significant inverse correlation existed between GR and the ratios of fPA contents to bPA levels. These results showed that, under salt stress, the balance between fSpd, fPAx and fPut levels and an equipoise between fPA and bPA contents in roots were important to salt tolerance of barley seedlings.
基金Supported by National Natural Science Foundation of China(30771296 )Basic and Front Technology Research Program of Henan Province (082300430310)Foundation of Henan Educational Committee (2007180052)~~
文摘[Objective]The research aimed to probe into the mechanism of polyamine enhancing the tolerance of plants to drought stress and provide theoretical basis for application of polyamine in process of maize drought resistance. [Method]With PEG-6000 simulating natural drought,the change in content of soluble protein and relative water content were investigated in seedling leaves of two maize cultivars,Nongda 108 and Yedan 13 under osmotic stress with exogenous Spd treatment. [Result]On the 7th day,leaf relative water content and the content of soluble protein decreased more significantly in leaves of Yedan 13 （drought-sensitive） than in Nongda 108 （drought-tolerant）. Exogenous Spd treatment not only obviously inhibited the decrease of leaf relative water content,but also increased the content of soluble protein. [Conclusion]Exogenous Spd treatment could enhance the tolerance of maize seedlings to osmotic stress,via improving the content of soluble protein in seedling leaves.
文摘The seeds of barley Hordeum vulgare L. cv. Jian 4) were soaked with 0.1 mmol/L putrescine (Put) and 0.5 mmol/L spermidine (Spd), and then the seedlings were treated with 200 mmol/L NaCl. The growth rate (GR), dry matter accumulation, distribution of ions, the amount of polyamines (PAs) bound to tonoplast proteins as well as lipid composition and the activity of tonoplast vesicles isolated from roots were investigated. The results showed that soaking with Put or Spd could retard salt injury, promote GR and dry matter accumulation, and increase K+/Na+ in the roots. Compared with NaCl_treated plants, phospholipid content in root tonoplast rose by soaking with Put and Spd, while the level of galactose in lipids was decreased. Moreover, the ratio in noncovalently conjugated PA contents of (Spd+PAx (an unknown PA)) to (Put+Dap (diaminopropane)), and the total contents of covalently and noncovalently conjugated PAs were all increased. Statistical analysis indicated that the ratio of (Spd+PAx) to (Put+Dap) was significantly and positively correlated with the activities of membrane associated enzymes H+_ATPase and H+_PPase.
基金Supported by the National Natural Science Foundation of China(31101117)National Key Technology Research and Development Program of China during the 12th Five-year Plan Period(2011BAD16B05,2012BAD04B13,2013BAD07B13)Rice Breeding Project in Sichuan Province of China(2011NZ0098-15)~~
文摘Salt stress is one of the worldwide abiotic stresses resulting in growth re- duction, chlorosis, wilting, and plant death. These exhibitions might result from men- tal toxicity and osmotic stress induced by salt. The two aspects of stress would af- fect vital metabolic pathways, reactive oxygen species scavenging system, lipid per- oxidation and photosynthetic apparatus. Thus, exploring ways to improve crop pro- ductivity or alleviate harmful effects under salt is one of the major areas of concern. Polyamines are aliphatic nitrogen organic cations which are implicated in a wide range of plant physiological processes such as morphogenesis, flower differentiation and initiation, they also play a role in biotic or abiotic stress responses. At the physiological level, polyamines modify the activities of many enzymes included in salt stress response and can bond to photosynthetic apparatus, thus changing the photosynthetic efficiency. At molecular level, polyamines can modify expressions of the polyamine-related genes directly or indirectly. Significant researches had been done to understand the effects of polyamines on plant salt resistance, but several questions still need to be answered. The present review is focused specifically on the effects of polyamines on physiological and molecular changes in plants under salt stress.
基金Supported by Agricultural Research Project of Guizhou Province([2010]No.3045)~~
文摘[Objective] This study aimed to investigate the effect of potyamine priming on physiological and biochemical variations of Lolium perenne embryos and seed germination. [Method] With annual Lolium perenne （Diamond T and Grazing-8000） as experimental materials, after priming with 0.5 mmol/L putrescine （Put）, spermidine （Spd） and spermine （Spm） for 24 h and chilling imbibition at 5 ℃ for 12, 24, 36 and 48 h, the effect of Put, Spd and Spm priming on chilling tolerance and germination ability of annual Lolium perenne seeds during imbibition was investigated. [Result] Put, Spd and Spm priming improved the activities of peroxidase （POD）, catalase （CAT）, superoxide dismutase （SOD） and ascorbate peroxidase （APX） and content of soluble protein content under low temperature stress, significantly in-creased the germination rate, and shortened the average germination duration. After chilling imbibition for 48 h, compared with the control, the average germination rate of annual Lolium perenne seeds was improved by 15.5% and 12.0% after Put, Spd and Spm priming, and the average germination duration was shortened by 1.21 and 1.14 d. During seed imbibition, the chilling tolerance of Grazing-8000 was stronger than that of Diamond T. Overall, Put, Spd and Spm treatment could increase the chilling tolerance of annual Lolium perenne seeds during imbibition, and improve the germination ability of seeds under low temperature stress. [Conclusion] Results of this study provided theoretical basis for the application of seed priming technology in the production of annual ryegrass.
文摘The effects of osmotic stress on the ATPase activity, the contents of —SH group and conjugated polyamines in mitochondrial membrane from wheat seedling [Triticum aestivum L. cv. Yumai No.18(drought-tolerant) and cv. Yumai No.9(drought-sensitive)] roots were investigated. The results showed that ATPase activity and —SH group content decreased with polyethylene glycol(PEG) 6000(-0.55 MPa) treatment for 7 d, in concert with the decrease of the ratio of noncovalently conjugated spermidine(NCC-Spd)/noncovalently conjugated putrescine(NCC-Put) and increase of the covalently conjugated putrescine(CC-Put). Osmotic stress injury to Yangmai No.9 seedlings was alleviated greatly with 1 mmol/L exogenous spermidine(Spd), in concert with marked increases of the ratio of NCC-Spd/NCC-Put, —SH group contents and ATPase activity in mitochondrial membrane. Under osmotic stress, the concomitant treatment of Yumai No.18 seedlings with methylglyoxyl bis(guanylhydrazone) (MGBG), an inhibitor of S-adenosyl methionine decarboxylase(SAMDC), and phenanthrolin (o-Phen), an inhibitor of transglutaminase(TGase), caused a significant decrease of the ratio of NCC-Spd / NCC-Put, CC-Put contents, respectively, in concert with the marked decreases of ATPase activity, —SH group content and its tolerance to osmotic stress. All the results above suggested that osmotic stress tolerance of wheat seedlings was associated with the ATPase activity, the contents of —SH group, NCC-Spd and CC-Put in mitochondrial membrane.
基金supported by the National Natural Science Foundation of China(Nos.30772753,81173254,and 81673940)the Science and Technology Program of Guangzhou(No.20160701335)the First-class discipline construction major project of Guangzhou University of Chinese Medicine(Guangzhou University of Chinese Medicine Planning,2018-No.6)
文摘Astragalus membranaceus(Radix Astragali, RA) and Atractylodes macrocephala(Rhizoma Atractylodis Macrocephalae, RAM) are often used to treat gastrointestinal diseases. In the present study, we determined the effects of polysaccharides extracts from these two herbs on IEC-6 cell migration and explored the potential underlying mechanisms. A migration model with IEC-6 cells was induced using a single-edged razor blade along the diameter of cell layers in six-well polystyrene plates. The cells were grown in control--media or media containing spermidine(5 μmol·L^(-1), SPD), alpha-difluoromethylornithine(2.5 mmol·L^(-1), DFMO), 4-Aminopyridine-(40 μ-mol·L^(-1), 4-AP), the polysaccharide extracts of RA or RAM(50, 100, or 200 mg·L^(-1)), DFMO plus SPD, or DFMO plus polysaccharide extracts of RA or RAM for 12 or 24 h. Next, cytosolic free Ca^(2+)([Ca^(2+)]cyt) was measured using laser confocal microscopy, and cellular polyamine content was quantified with HPLC. Kv1.1 mRNA expression was assessed using RT-qPCR and Kv1.1 and RhoA protein expressions were measured with Western blotting analysis. A cell migration assay was carried out using Image-Pro Plus software. In addition, GC-MS was introduced to analyze the monosaccharide composition of both polysaccharide extracts. The resutls showed that treatment with polysaccharide extracts of RA or RAM significantly increased cellular polyamine content, elevated [Ca^(2+)]cyt and accelerated migration of IEC-6 cells, compared with the controls(P < 0.01). Polysaccharide extracts not only reversed the inhibitory effects of DFMO on cellular polyamine content and [Ca^(2+)]cyt, but also restored IEC-6 cell migration to control level(P < 0.01 or < 0.05). Kv1.1 mRNA and protein expressions were increased(P < 0.05) after polysaccharide extract treatment in polyamine-deficient IEC-6 cells and RhoA protein expression was increased. Molar ratios of D-ribose, D-arabinose, L-rhamnose, D-mannose, D-glucose, and D-galactose was 1.0:14.1:0.3:19.9:181.3:6.3 in RA and 1.0:4.3:0.1:5.7:2.8:2.2 in RAM. In conclusion, treatment with RA and RAM polysaccharide extracts stimulated migration of intestinal epithelial cells via a polyamine-Kv1.1 channel activated signaling pathway, which facilitated intestinal injury healing.
基金supported by the National Natural Science Foundation of China(30970228 and 31170237)the National Science Foundation of Shandong Province,China(ZR2010CM024)the Foundation of State Key Laboratory of Plant Physiology and Biochemistry,China(SKLPPBKF11001)
文摘Hydrogen peroxide （H2O2） is an important signaling molecule in ethylene-induced stomatal closure in Arabidopsis thaliana. Early studies on the sources of H2O2 mainly focused on NADPH oxidases and cell-wall peroxidases. Here, we report the involvement of polyamine oxidases （PAOs） in ethylene-induced H2O2 production in guard cells. In Arabidopsis epidermal peels, application of PAO inhibitors caused the failure of ethylene to induce H2O2 production and stomatal closure. Results of quantitative RT-PCR analysis and pharmacological experiments showed that AtPAO2 and AtPAO4 transcripts and activities of PAOs were both induced by ethylene. In transgenic Arabidopsis plants over-expressing AtPAO2 and AtPAO4, stomatal movement was more sensitive to ethylene treatment and H2O2 production was also significantly induced. The increased H2O2 production in the transgenic lines compared to the wild-type plants suggests that AtPAO2 and AtPAO4 probably are involved in ethylene-induced H2O2 production. Several factors which induce stomatal closure such as dehydration and high salinity all enhanced the expression of AtPAO2 and AtPAO4 to different degrees. Moreover, GFP- AtPAOs fusion protein localized in the nucleus, cytoplasm, and cell wall of the guard cells. Therefore, our results strongly indicated that PAO is a source of H2O2 generation in Arabidopsis guard cells and plays crucial roles in stomatal movement.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions and Program for Student Innovation through Research and Training(SRT),China(1918C12)。
文摘The mechanism of melatonin(MT)induced chilling tolerance in harvested cucumber fruit was investigated at commercial maturity.In this study,cucumber fruits were treated with 100μmol L^(-1) MT at 4℃ and 90% relative humidity for 15 d of storage.In comparison with the control,cucumber treatment with MT resulted in reduced chilling injury(CI),decreased electrolyte leakage and enhanced firmness.The fruits treated with MT showed higher chlorophyll contents in storage conditions with suppressed chlorophyllase enzyme activity.MT treatment increased arginine decarboxylase(ADC)and ornithine decarboxylase(ODC)enzyme activities.Moreover,enhanced expression of the Cucumis sativus ADC(CsADC)and C.sativus ODC(CsODC)genes resulted in the accumulation of polyamine contents.Similarly,proline levels exhibited higher levels among treated fruits.Meanwhile,the proline synthesizing enzymes △1-pyrroline-5-carboxylate syntheses(P5CS)and ornithine aminotransferase(OAT)were significantly increased,while a catabolic enzyme of proline dehydrogenase(PDH)activity was inhibited by treatment.In addition,MT induced expression of C.sativus OAT(CsOAT)and C.sativus P5CS(CsP5CS)genes.Cucumber fruits treated with MT also exhibited higher γ-aminobutyric acid(GABA)content by enhanced GABA transaminase(GABA-T)and glutamate decarboxylase(GAD)enzyme activities and a higher C.sativus GAD(CsGAD)gene expression.To sum up,the results show that MT treatment enhanced chilling tolerance,which was associated with the regulation of polyamines,as well as proline and γ-aminobutyric acid.
基金the National Natural Science Foundation of China (30671452 and 31171923)
文摘The free putrescine （Put） content, the hydrogen peroxide （H202） content and the polyamine oxidase （PAO） activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang （PYTC） were significantly increased, and reached its peak at 1, 2 and 6 h, respectively, under cadmium treatment. The free spermine （Spin） and spermidine （Spd） contents were dramatically decreased, and reached the minimum value at 4-6 h, then remained relatively stable. The change in total free polyammes （PAs） content was consistent with that of free Put. The number of root dead cells was gradually increased after treatment for 24 h, and the typical characteristics of programmed cell death （PCD） were displayed at 48 h. Throughout the Cd treatment process, changes in PAs metabolism appeared to be prior to cell death increase, and the H2O2 content was always maintained at a high level. These results indicated that polyamines could initiate cell death by generating H2O2 in roots of Malus hupehensis Rehd. under CdSO4 stress.
基金supported by the National Natural Science Foundation of China(31301260)the National Key Technologies R&D Program of China during the 12th Five-Year Plan period(2015BAD22B03)the China Postdoctoral Science Foundation(2015M572603)
文摘Drought is a multifaceted stress condition that inhibits crop growth.Seed germination is one of the critical and sensitive stages of plants,and its process is inhibited or even entirely prevented by drought.Polyamines(PAs)are closely associ-ated with plant resistance to drought stress and seed germination.However,little is known about the effect of PA on the seed germination of wheat under drought stress.This study investigated the involvement of PAs in regulating wheat seed germination under drought stress.Six wheat genotypes differing in drought resistance were used,and endogenous PA levels were measured during seed germination under different water treatments.In addition,external PAwas used for seed soaking and the variation of hormones,total soluble sugar and starch were measured during the seed germination under different water treatments.These results indicated that the free spermidine(Spd)accumulation in seeds during the seed germination period favored wheat seed germination under drought stress;however,the free putrescine(Put)accumulation in seeds during the seed germination period may work against wheat seed germination under drought stress.In addition,seed soaking in Spd and spermine(Spm)significantly relieved the inhibition of seed germination by drought stress;howev-er,soaking seeds in Put had no significant effect on seed germination under drought.External Spd and Spm significantly increased the endogenous indole-3-acetic acid(IAA),zeatin(Z)+zeatin riboside(ZR),abscisic acid(ABA),and gibberellins(GA)contents in seeds and accelerated the seed starch degradation and increased the concentration of soluble sugars in seeds during seed germination.This may promote wheat seed germination under drought stress.In conclusion,free Spd and Put are key factors for regulating wheat seed germination under drought stress and the effects of Spd and Put on seed germination under drought notably related to hormones and starch metabolism.
基金supported by the Science and Technology Department(No.04JY029-018)Education Department of Sichuan Province(No.2006ZD049).
文摘The activities of the catalytic hydrolysis of phosphate diester （BNPP） [bis（p-nitrophenyl）phosphate diester] and plasmid DNA （pUC 18） by mononuclear macrocyclic polyamine metal complexes have been investigated in this paper. The results showed that the highest activity in hydrolysis of BNPP was obtained with le--Zn（II） complex （composed of lipophilic group） as catalyst. The hydrolysis rate enhancement is up to 3.64 × 10^4 fold. These metal complexes could effectively promote the cleavage of plasmid DNA （pUC18） at physiological conditions.
基金supported by grants from the National Basic Research Program of China(No.2012CB114306)the National Natural Science Foundation of China(Nos.31461143015,31271641,and 31471438)+3 种基金the National Key Technology R&D Program of China(Nos.2012BAD04B08 and 2014AA10A605)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Top Talent Supporting Program of Yangzhou University(No.2015-01)Jiangsu Creation Program for Post-graduation Students(No.KYZZ15_0364)
文摘Polyamines(PAs) are important endogenous plant growth regulators responding to environmental stress and mediating many physiological processes including grain filling in cereals.This study investigated whether PAs mediate the effect of post-anthesis soil drying on starch granule size distribution,starch content,and weight of superior and inferior kernels of wheat(Triticum aestivum L.).Two wheat cultivars were grown in pots.Three treatments,well-watered(WW),moderate soil drying(MD) and severe soil drying(SD),were imposed from 9 days post-anthesis until maturity.PA levels in kernels and small,medium and large granules were measured.The results showed that superior kernels had much higher free spermidine(Spd) and free spermine(Spm) concentrations,larger volumes of medium starch granules,and smaller-sized large granules than did inferior kernels under all the treatments.Compared to WW,MD significantly increased the concentrations of free Spd and free Spm,activities of soluble starch synthase and granule-bound starch synthase,volume of medium granules,and starch content and kernel weight of inferior kernels,and decreased the size of large granules.SD produced the opposite effect.Application of Spd or Spm to spikes produced effects similar to those of MD,and application of an inhibitor of Spd and Spm synthesis produced effects similar to those of SD.These results suggest that PAs mediate the effect of post-anthesis soil drying on starch biosynthesis in wheat kernels by regulating key enzymes in starch synthesis and that elevated PA levels under MD increase the volume of medium granules and kernel weight of inferior kernels.
文摘The relationship between gross domestic pro- duct (GDP) and dietary profile, with a focus on polyamine intake, was investigated in 35 Asian countries. Data on food supply, GDP, and health condition were collected from databases of the United Nations, the International Monetary Fund, and the World Health Organization, respectively. The amount of polyamine intake from food was estimated using polyamine concentrations listed in published sources. The amounts of putrescine, spermidine, spermine, and total polyamines in 1000 kcal of food in Asian countries were 39.07 ± 17.98, 33.74 ± 14.35, 14.05 ± 6.60 and 86.85 ± 33.96 μmol/1000 kcal, respectively. Putrescine, spermidine, and spermine constituted 44, 39, and 17% of total polyamine, respectively. Vegetables contributed the largest amount of both putrescine and spermidine and the second largest amount of spermine (45.5%, 62.2% and 27.2% of total putrescine, spermidine, and spermine, respectively). Meat was the richest source of spermine and contributed the greatest amount (50%) of this polyamine. We showed a significant positive association between GDP and the amount of polyamine per 1000 kcal of food. Lifespan was associated with both GDP and the amount of polyamine per energy quotient of food. As several basic research studies have shown that polyamines help prolong longevity, it follows that polyamines may have a role in determining the lifespan of humans.
文摘<abstract>Aim: To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis. Methods: Male golden hamsters of 7-week-old were kept under a light and dark cycle of 14 h and 10 h for 1 week to stimulate maximally the gonadal function. DES was injected subcutaneously at doses of 0.01 mg·kg-1·day-1, 0.1 mg·kg-1·day-1 and 1 mg·kg-1·day-1 for one week. Results: DES treatment caused a significant decrease in the weight of epididymis. The activity of epididymal ornithine decar boxylase (ODC) increased 1 day after DES treatment, kept at a high level for 4 days and then decreased to nearly normal level at day 7. The activity of spermidine/spermine N1-acetyltransferase (SSAT) also increased transiently after DES treatment. The contents of putrescine, spermidine, spermine and N1-acetylspermidine were increased 1 day -4 days after DES treatment and restored to normal at day 7. All these changes showed a marked difference between the caput and the cauda. Conclusion: The polyamine biosynthesis in the hamster epididymis can be affected by DES, a xenoestrogen. DES may probably affect polyamine metabolism in the epididymis by regulating the rate-limiting enzymes involved in the polyamine biosynthesis.
