The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrare...The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrared spectrum, powder X-ray diffraction and so on. The results show that under experimental conditions, the ligands of synthesized copper nicotinate and copper isonicotinate are coordinated simultaneity with copper（Ⅱ） via the nitrogen of pyridine group and an oxygen of carboxylic acid group to form bidentate chelates. The crystal of copper nicotinate with two six-membered chelate rings belongs to monoclinic system, while that of copper isonicotinate having two five-membered chelate rings is of triclinic system. The tests show that the biological activities, such as the improvement of feed utilization, growth, anti-oxidation ability of organism and disease-resistant power, are different when copper nicotinate, copper inicotinate, copper-lysine chelate, copper-methionine chelate and copper sulphate are added in pig＇s feed, respectively. Due to its higher biological activity, less pollution and lower toxicity, copper nicotinate has wide potential applications as a feed additive.展开更多
A novel compound-monohydrated zinc nicotinate was prepared via room temperature solid phase synthesis and ball grinding.FTIR,chemical and elemental analyses and X-ray powder diffraction technique were applied to chara...A novel compound-monohydrated zinc nicotinate was prepared via room temperature solid phase synthesis and ball grinding.FTIR,chemical and elemental analyses and X-ray powder diffraction technique were applied to characterizing the structure and composition of the complex.Low-temperature heat capacities of the solid coordination compound were measured by a precision automated adiabatic calorimeter over a temperature range from 77 to 400 K.A solid-solid phase transition process occurred in a temperature range of 321―342 K inferred according to the heat capacity curve,and the peak temperature,molar enthalpy and entropy of the phase transition of monohydrated zinc nicotinate were determined to be Ttrs=（340.584±0.829） K,ΔtrsHm=（12.682±0.041） kJ/mol and ΔtrsSm=（37.235±0.101） KJ/mol）.The experimental values of the molar heat capacities in the temperature regions of 77―321 K and 342―400 K were,respectively,fitted to two polynomial equations.In addition,the polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K.展开更多
The electrochemistry of xanthinol nicotinate （Xan） was studied by cyclic voltammetry at a glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes （MWNTs） and room-temperature ionic liqui...The electrochemistry of xanthinol nicotinate （Xan） was studied by cyclic voltammetry at a glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes （MWNTs） and room-temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate （BMIMPF6）. The modified electrode exhibited good promotion to the electrochemical oxidation of Xan and an ultrasensitive electrochemical method was proposed for the determination of Xan. This method was successfully applied to the determination of Xan in Xan tablets. C 2009 XiaoYu Bao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
A heterometallic metal-organic framework, Agln（nicotinate）4.1.5DMF, was obtained from the reaction of nicotinic acid, AgNO3 and In（NO3）3 in DMF. The complex was characterized by elemental analysis, infrared spectr...A heterometallic metal-organic framework, Agln（nicotinate）4.1.5DMF, was obtained from the reaction of nicotinic acid, AgNO3 and In（NO3）3 in DMF. The complex was characterized by elemental analysis, infrared spectrum, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Crystal data are： C28.5H26.5N55O9.5Agln, orthorhombic space group/222, a = 10.775（15）, b = 11.939（18）, c = 13.93（2） A, V= 1792（5） A3, Z = 2, Dc = 1.521 mg/m3,μ = 1.244 mm1, F（000） = 816, the final R = 0.0672 and wR= 0.1812 for 1912 observed reflections with I 〉 2σ（I）. Single-crystal X-ray structure analysis reveals that nicotinate bridges In（III） and Ag（I） through carboxylate chelating with In（III） and pyridyl nitrogen atom coordinating to Ag（I）, generating a new 2D network consisting of tetrahedral building units of [AgN4]＋ and [In（COO）4]-.展开更多
Nicotinamide adenine dinucleotide （NAD） biosynthesis, including synthesis from aspartate via the de novo pathway and from nicotinate （NA） via the Preiss-Handler pathway, is conserved in land plants. Diverse spe-ci...Nicotinamide adenine dinucleotide （NAD） biosynthesis, including synthesis from aspartate via the de novo pathway and from nicotinate （NA） via the Preiss-Handler pathway, is conserved in land plants. Diverse spe-cies of NA conjugates, which are mainly involved in NA detoxification, were also found in all tested land plants. Among these conjugates, MeNA （NA methyl ester） has been widely detected in angiosperm plants, although its physiological function and the underlying mechanism for its production in planta remain largely unknown. Here, we show that MeNA is an NAD precursor undergoing more efficient long-distance trans-port between organs than NA and nicotinamide in Arabidopsis. We found that Arabidopsis has one meth- yltransferase （designated AtNaMT1） capable of catalyzing carboxyl methylation of NA to yield MeNA and one methyl esterase （MES2） predominantly hydrolyzing MeNA back to NA. We further uncovered that the transfer of [^14C]MeNA from the root to leaf was significantly increased in both MES2 knockdown and NaMTl-overexpressing lines, suggesting that both NaMT1 and MES2 fine-tune the long-distance transport of MeNA, which is ultimately utilized for NAD production. Abiotic stress （salt, abscisic acid, and mannitol） treatments, which are known to exacerbate NAD degradation, induce the expression of NaMT1 but sup-press MES2 expression, suggesting that MeNA may play a role in stress adaption. Collectively, our study indicates that reversible methylation of NA controls the biosynthesis of MeNA in Arabidopsis, which pre-sumably functions as a detoxification form of free NA for efficient long-distance transport and eventually NAD production especially under abiotic stress, providing new insights into the relationship between NAD biosynthesis and NA conjugation in plants.展开更多
The evolutionarily conserved mitogen-activated protein kinase(MAPK)cascades relay extracellular signals into cells,triggering a variety of cellular responses.We previously revealed NtMPK4 as a positive regulator of ni...The evolutionarily conserved mitogen-activated protein kinase(MAPK)cascades relay extracellular signals into cells,triggering a variety of cellular responses.We previously revealed NtMPK4 as a positive regulator of nicotine biosynthesis;however,its upstream regulation remains unclear.Here,we characterized a MAPK cascade,comprising NtMEKK1b,NtMPKK2a,and NtMPK4,that promotes nicotine biosynthesis.This signaling module transduces external cues,including jasmonate and pathogen elicitors such as flg22,into post-translational modifications that enhance transcriptional activity and pathway gene expression.NtMPKK2a physically interacts with and phosphorylates NtMPK4 in vivo,confirming its role as an upstream kinase.RNAi-mediated silencing of NtMPKK2a significantly reduced the expression of nicotine pathway genes and decreased nicotine accumulation,whereas induced-overexpression of NtMPKK2a upregulated nicotine pathway genes and increased nicotine contents in tobacco hairy roots.Overexpression of NtMPKK2a in tobacco cells enhanced the transactivation activity of a NIC2-locus Ethylene Response Factor NtERF221 on Putrescine N-methyltransferase(NtPMT)promotor,further supporting its role in promoting nicotine biosynthesis.Furthermore,we identified NtMEKK1b,a tobacco MEKK that interacts with NtMAPKK2a in yeast cells.Knock-down of NtMEKK1b in transgenic tobacco plants attenuated the expression of nicotine pathway genes and reduced nicotine contents,whereas induced-overexpression of NtMEKK1b upregulated gene expression and nicotine accumulation.Our findings uncover a previously uncharacterized MAPK cascade module,NtMEKK1b-NtMPKK2a-NtMPK4,that regulates nicotine biosynthesis,highlighting the importance of posttranslational regulation in nicotine biosynthesis.展开更多
Numerous pathological states of the nervous system involve alterations in neuronal excitability and synaptic dysfunction,which depend on the function of ion channels.Due to their critical involvement in health and dis...Numerous pathological states of the nervous system involve alterations in neuronal excitability and synaptic dysfunction,which depend on the function of ion channels.Due to their critical involvement in health and disease,the search for new compounds that modulate these proteins is still relevant.Traditional medicine has long been a rich source of neuroactive compounds.For example,the indigenous Mapuche people have used the leaves and bark of the Drimys winteri tree for centuries to treat various diseases.Consequently,several studies have investigated the biological effects of compounds in Drimys winteri,highlighting sesquiterpenes such asα-humulene,drimenin,polygodial,andα-,β-,γ-eudesmol.However,there is currently no literature review focusing on the ability of these sesquiterpenes to modulate ion channels.This review summarizes the current knowledge about neuroactive compounds found in Drimys winteri,with special emphasis on their direct actions on neuronal ion channels.Several Drimys winteri sesquiterpenes modulate a diverse array of neuronal ion channels,including transient receptor potential channels,gamma-aminobutyric acid A receptors,nicotinic acetylcholine receptors,and voltage-dependent Ca^(2+)and Na^(+)channels.Interestingly,the modulation of these molecular targets by Drimys winteri sesquiterpenes correlates with their therapeutic actions.The promiscuous pharmacological profile of Drimys winteri sesquiterpenes suggests they modulate multiple protein targets in vivo,making them potentially useful for treating complex,multifactorial diseases.Further studies at the molecular level may aid in developing multitargeted drugs with enhanced therapeutic effects.展开更多
It is a common misconception that e-cigarettes are safer than tobacco smoking,given their adverse cardiopulmonary effects,habituation,and the fact that it is only a fashion based manifestation to sell and use them.The...It is a common misconception that e-cigarettes are safer than tobacco smoking,given their adverse cardiopulmonary effects,habituation,and the fact that it is only a fashion based manifestation to sell and use them.Therefore,the use of e cigarettes should not be encouraged as an alternative and pragmatic measure should be taken to profess this agenda.展开更多
Imidacloprid,a neonicotinoid insecticide,is widelyused in agriculture as a safer alternative to highly toxicorganophosphates.It targets nicotinic acetylcholinereceptors in pests and is generally low in toxicity tohuma...Imidacloprid,a neonicotinoid insecticide,is widelyused in agriculture as a safer alternative to highly toxicorganophosphates.It targets nicotinic acetylcholinereceptors in pests and is generally low in toxicity tohumans.However,large ingestions can cause severe,life-threatening complications,with no establishedtreatment protocols.Though rarely fatal,imidaclopridpoisoning is increasingly reported in agricultural regions,particularly in Southeast Asia,with most cases involvingsuicide attempts.展开更多
[Objectives]To elucidate the impact of different drying temperatures on the biochemical profile of tobacco(Nicotiana tabacum L.)leaves,the chemical constituents and ultrastructure of Yunyan 87 leaves subjected to diff...[Objectives]To elucidate the impact of different drying temperatures on the biochemical profile of tobacco(Nicotiana tabacum L.)leaves,the chemical constituents and ultrastructure of Yunyan 87 leaves subjected to different curing temperature settings.[Methods]Near-infrared spectroscopy techniques were utilized to analyze tobacco leaf samples,comparing the changes in chemical constituents at different curing temperatures.[Results]The CK treatment resulted in lower concentrations of nicotine,total nitrogen,chlorine,potassium,and starch,while simultaneously enhancing the levels of total sugar,reducing sugar,and protein.In comparison to the T treatment,the CK treatment appropriately altered the cell structure,reducing the content of cell wall substances.[Conclusions]These findings suggest that low-temperature curing at 44℃during the color-fixing stage is beneficial for improving the quality of tobacco leaves.展开更多
To investigate the differences in physical and chemical indicators of tobacco stems from different parts of the‘Honghuadajinyuan’variety in the Dali tobacco-growing area,a comparative analysis of these indicators wa...To investigate the differences in physical and chemical indicators of tobacco stems from different parts of the‘Honghuadajinyuan’variety in the Dali tobacco-growing area,a comparative analysis of these indicators was conducted.The results showed that in terms of physical indicators,the tobacco stem length and content in middle part were significantly higher than those in other parts;the filling value of cut stems in upper part was significantly better than that in the middle and lower parts.In terms of chemical compositions,the content of total sugar and reducing sugar in middle part were the highest;the content of nicotine,total chlorine,and chlorine in upper part were the highest;the difference between total sugar and reducing sugar,sugar-to-nicotine ratio,nitrogen-to-nicotine ratio,and potassium-to-chlorine ratio in middle part were the best;and the potassium content in lower part was significantly higher than that in other parts.Correlation analysis showed that equilibrium moisture content was significantly positively correlated with total nitrogen content.Among them,equilibrium moisture content in upper part was positively correlated with nicotine content,and equilibrium moisture content in middle part was positively correlated with potassium and chlorine content.In addition,the filling value of cut stems in lower part was positively correlated with reducing sugar and total nitrogen content,while the filling value of cut stems in all parts was negatively correlated with the difference between total sugar and reducing sugar,sugar-to-nicotine ratio,and nitrogen-to-nicotine ratio.展开更多
Background:Triple-negative(TN)breast cancer,the most aggressive subtype of breast cancer,is usually treated with high doses of paclitaxel(PX),which induces resistance.To prevent this adverse effect,metronomic chemothe...Background:Triple-negative(TN)breast cancer,the most aggressive subtype of breast cancer,is usually treated with high doses of paclitaxel(PX),which induces resistance.To prevent this adverse effect,metronomic chemotherapy based on administering low doses of PX plus carbachol(Carb),a muscarinic acetylcholine receptor(mAChR)agonist,has emerged as an alternative.Other acetylcholine receptors also present in breast tissue are nicotinic ones.When activated by nicotine(Nic),these receptors can decrease the effectiveness of conventional chemotherapy.However,whether metronomic chemotherapy with PX and Carb is affected by Nic has not yet been described.This study aimed to determine the efficacy of metronomic chemotherapy with PX and Carb in human breast tumor MDA-MB-231 cells in the presence or absence of Nic and assess the intermediaries involved.Methods:Cell viability and proliferation were determined using colorimetric assays with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)and trypan blue.Nitrite levels in cell supernatant were determined using Griess reagent.The expression of proteins was determined by western blot assays.Apoptosis/necrosis and the proportion of cancer stem cells(CSC)were determined by flow cytometry.Mammosphere-forming units were determined with anchorage-free growth assays.Results:The metronomic chemotherapy combining PX and Carb effectively inhibited the viability of TN MDA-MB-231 cells in the presence and absence of Nic.These effects were mediated by the activation of mAChRs,triggering signaling pathways dependent on several kinases.These mediators induce increased expression of the inducible isoform of nitric oxide synthase(NOS).Only the inducible and endothelial isoforms were expressed in these cells,and their activity was increased by the metronomic chemotherapy with PX and Carb.Nitric oxide(NO),a product of NOS activity,may contribute to the observed increase in apoptosis.We also observed an increased sensitivity to PX in the residual cells after the metronomic chemotherapy,as well as a decrease in mammosphere-forming units and CSC proportion.We also determined a decrease in the expression of stemness proteins such as ATP-binding cassette super-family G member 2(ABCG2),sex-determining region Y-box 2(SOX2),octamer-binding transcription factor 4(OCT-4),and Nanog.Conclusions:Metronomic chemotherapy combining PX with Carb was selective for MDA-MB-231 cells and increased their sensitivity to conventional chemotherapy in the presence and absence of Nic,indicating that it could be a useful neoadjuvant strategy for the treatment of TN breast tumors.展开更多
BACKGROUND:While theα7 nicotinic acetylcholine receptor(α7 nAChR)is implicated in sepsis-associated encephalopathy(SAE),its pathophysiological contributions require further investigation.METHODS:SAE was induced in m...BACKGROUND:While theα7 nicotinic acetylcholine receptor(α7 nAChR)is implicated in sepsis-associated encephalopathy(SAE),its pathophysiological contributions require further investigation.METHODS:SAE was induced in mice via cecal ligation and puncture(CLP),and microglia were treated with lipopolysaccharide(LPS).PHA-543613(anα7 nAChR agonist)was used to activateα7 nAChR.To study the role ofα7 nAChR in mitophagy and pyroptosis,caspase-1-deficient mice and PTEN-induced kinase 1(PINK1)small interfering RNA(siRNA)were used.Cognitive function,cerebral oxygen extraction ratio(CERO2),and brain tissue oxygen pressure(PbtO2)were measured.Blood-brain barrier(BBB)integrity was evaluated via Evan’s blue staining.Mitophagy,pyroptosis,and cytokine levels were analyzed via Western blotting and immunofl uorescence.RESULTS:CLP or LPS treatment signifi cantly down-regulatedα7 nAChR protein expression in microglia.The administration of PHA-543613 to activateα7 nAChR not only restored its expression post-sepsis,but also notably decreased BBB permeability and mitigated cognitive deficits.Bothα7 nAChR activation and caspase-1 knockout effectively suppressed microglial pyroptosis.The activation ofα7 nAChR also promoted mitophagy in microglia.This led to an amelioration of brain tissue hypoxia,as shown by elevated PbtO2 and reduced CERO2 levels.The suppression of microglial pyroptosis byα7 nAChR was counteracted when mitophagy was inhibited through the siRNA-mediated silencing of PINK1.CONCLUSION:The activation ofα7 nAChR reduces pyroptosis by enhancing microglial mitophagy,thereby mitigating SAE.展开更多
Nicotine,ethanol,and caffeine are the most common exogenous substances in the men’s living environment,but their effects on the cartilage quality in the father and offspring have not been reported.According to the av...Nicotine,ethanol,and caffeine are the most common exogenous substances in the men’s living environment,but their effects on the cartilage quality in the father and offspring have not been reported.According to the average daily intake of adult men,we constructed a male rat model of paternal mixed exposure(PME)to low-dose nicotine(0.1 mg/(kg·day)),ethanol(0.5 g/(kg·day)),and caffeine(7.5 mg/(kg·day))for 8 weeks.Then,the male rats mated with normal female rats to obtain offspring.The results showed that PME reduced the cartilage quality of paternal and offspring rats.Among them,the paternal cartilage was damaged by enhancing matrix degradation,while the offspring cartilage was damaged by reducing matrix synthesis.The cartilage damage in male offspring rats was more evident than in female offspring.It was further confirmed that differential GC regulation mechanisms were the main reasons for the intergenerational differential damage of paternal/offspring cartilage quality caused by PME.In addition,the androgen receptor(AR)and estrogen receptor beta(ERβ)mediated the sex difference of PME-induced fetal cartilage dysplasia by affecting the binding degree of GR/P300.This study provided a theoretical and experimental basis for guiding male healthy lifestyle and exploring early prevention and treatment strategies for paternal diseases.展开更多
Background Verticillium dahliae,a soil-borne fungi,can cause Verticillium wilt,and seriously diminish the yield and quality of cotton.However,the pathogenic mechanism of V.dahliae is complex and not clearly understood...Background Verticillium dahliae,a soil-borne fungi,can cause Verticillium wilt,and seriously diminish the yield and quality of cotton.However,the pathogenic mechanism of V.dahliae is complex and not clearly understood at the moment.This study aimed to identify the high-affinity nicotinic acid transporter genes in V.dahliae.The gene expression profiles in V.dahliae following sensing of root exudates from susceptible and resistant cotton varieties were analyzed.The function of VdNAT1 in the pathogenic process of V.dahliae was studied using the tobacco rattle virus(TRV)-based host-induced gene silencing(HIGS)technique.Results Eight high-affinity nicotinic acid transporter genes were identified from V.dahliae through the bioinformatics method.Each protein contains a conserved major facilitator superfamily(MFS)domain,which belongs to the MFS superfamily.Evolutionary relationship analysis revealed that all 8 genes belong to the anion:cation symporter(ACS)subfamily.All proteins have transmembrane domains,ranging from 7 to 12.The expression levels of most VdNAT genes were significantly increased after induction by root exudates from susceptible cotton varieties.Silencing VdNAT1 gene by HIGS significantly inhibited the accumulation of fungal biomass in cotton plants,and alleviated the disease symptoms of cotton.Conclusions Eight VdNAT genes were identified from V.dahliae,and most VdNAT genes was up-regulated after induced by root exudates from susceptible cotton variety.In addition,VdNAT1 is required for the pathogenicity of V.dahliae.Overall,these findings will facilitate the pathogenic molecular mechanism of V.dahliae and provide candidate genes.展开更多
Nicotine,also known as nicotinic norephedrine,is one of the main alkaloids present in tobacco plants.In recent years,due to the increase in tobacco production and smoking population,the environmental and health issues...Nicotine,also known as nicotinic norephedrine,is one of the main alkaloids present in tobacco plants.In recent years,due to the increase in tobacco production and smoking population,the environmental and health issues caused by nicotine have become increasingly severe.Traditional methods have proven ineffective in efficiently degrading residual nicotine.To address this issue,scientists both domestically and internationally have turned to biodegradation methods to tackle the environmental and health problems caused by residual nicotine.In this study,an enrichment method was used to screen bacteria with nicotine-degrading capabilities from the soil of tobacco planting sites at the Tobacco Research Institute of Heilongjiang in Bin County,Harbin City.Through phenotypic observations and 16S rDNA identification,a bacterial strain identified as Pseudomonas hunanensis MGJ-2 was isolated,capable of utilizing nicotine as a carbon and nitrogen source for growth.High-performance liquid chromatography(HPLC)-1 analysis revealed that within 25 h,strain MGJ-2 could degrade nicotine 500 mg·L^(-1) with an efficiency exceeding 99.9%.Strain MGJ-2 was applied to tobacco,and after 15 days of incubation and fermentation,it degraded 10.57%of nicotine in tobacco.Overall,the discovery of strain MGJ-2 enriched the resources of nicotine-degrading strains.Its remarkable biodegradation performance held immense potential for future biodegradation of nicotine in tobacco.展开更多
Nicotinic acetylcholine receptors (nAChRs) play a significant role in excitatory synaptic transmission in insects and are the target for chloronicotinyl and nereistoxin insecticides.In recent years,Chilo suppressalis,...Nicotinic acetylcholine receptors (nAChRs) play a significant role in excitatory synaptic transmission in insects and are the target for chloronicotinyl and nereistoxin insecticides.In recent years,Chilo suppressalis,an economically important pest of rice,developed high resistance against monosultap,a nereistoxin insecticide acting on nAChR.In order to reveal the hypothesized target insensitive mechanism,studies on the molecular property of nAChR from Chilo suppressalis are required.In this study,the full length cDNA of nAChR α subunit from this pest was cloned by RT-PCR.Sequence analysis shows that it is a novel nAChR α subunit,which was named as Cs α 1(Genbank accession No.AF418987).It contains 1?997?bp nucleotides and involves an open reading frame (ORF) encoding a mature protein of 509 amino acids excluding a signal peptide of 24 amino acids.The deduced amino acid sequence was 52%-94% identical to the reported insect nAChR genes.展开更多
基金Supported by the Natural Science Foundation of Fujian Province (B0510012) and the Science and Technology of Science Foundation of Fujian Education Department (JA04189)
文摘The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrared spectrum, powder X-ray diffraction and so on. The results show that under experimental conditions, the ligands of synthesized copper nicotinate and copper isonicotinate are coordinated simultaneity with copper（Ⅱ） via the nitrogen of pyridine group and an oxygen of carboxylic acid group to form bidentate chelates. The crystal of copper nicotinate with two six-membered chelate rings belongs to monoclinic system, while that of copper isonicotinate having two five-membered chelate rings is of triclinic system. The tests show that the biological activities, such as the improvement of feed utilization, growth, anti-oxidation ability of organism and disease-resistant power, are different when copper nicotinate, copper inicotinate, copper-lysine chelate, copper-methionine chelate and copper sulphate are added in pig＇s feed, respectively. Due to its higher biological activity, less pollution and lower toxicity, copper nicotinate has wide potential applications as a feed additive.
基金Supported by the National Natural Science Foundation of China(No.20673050)Key Project of Science Foundation from Shaanxi Educational College of China(No.08KJ017)
文摘A novel compound-monohydrated zinc nicotinate was prepared via room temperature solid phase synthesis and ball grinding.FTIR,chemical and elemental analyses and X-ray powder diffraction technique were applied to characterizing the structure and composition of the complex.Low-temperature heat capacities of the solid coordination compound were measured by a precision automated adiabatic calorimeter over a temperature range from 77 to 400 K.A solid-solid phase transition process occurred in a temperature range of 321―342 K inferred according to the heat capacity curve,and the peak temperature,molar enthalpy and entropy of the phase transition of monohydrated zinc nicotinate were determined to be Ttrs=（340.584±0.829） K,ΔtrsHm=（12.682±0.041） kJ/mol and ΔtrsSm=（37.235±0.101） KJ/mol）.The experimental values of the molar heat capacities in the temperature regions of 77―321 K and 342―400 K were,respectively,fitted to two polynomial equations.In addition,the polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the sample relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K.
基金the financial support of the Takle Key Problem of ScienceTechnology of Nanyang City,PR China(No.2006G0707).
文摘The electrochemistry of xanthinol nicotinate （Xan） was studied by cyclic voltammetry at a glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes （MWNTs） and room-temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate （BMIMPF6）. The modified electrode exhibited good promotion to the electrochemical oxidation of Xan and an ultrasensitive electrochemical method was proposed for the determination of Xan. This method was successfully applied to the determination of Xan in Xan tablets. C 2009 XiaoYu Bao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金supported by the National Natural Science Foundation of China(No.21401195)
文摘A heterometallic metal-organic framework, Agln（nicotinate）4.1.5DMF, was obtained from the reaction of nicotinic acid, AgNO3 and In（NO3）3 in DMF. The complex was characterized by elemental analysis, infrared spectrum, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Crystal data are： C28.5H26.5N55O9.5Agln, orthorhombic space group/222, a = 10.775（15）, b = 11.939（18）, c = 13.93（2） A, V= 1792（5） A3, Z = 2, Dc = 1.521 mg/m3,μ = 1.244 mm1, F（000） = 816, the final R = 0.0672 and wR= 0.1812 for 1912 observed reflections with I 〉 2σ（I）. Single-crystal X-ray structure analysis reveals that nicotinate bridges In（III） and Ag（I） through carboxylate chelating with In（III） and pyridyl nitrogen atom coordinating to Ag（I）, generating a new 2D network consisting of tetrahedral building units of [AgN4]＋ and [In（COO）4]-.
文摘Nicotinamide adenine dinucleotide （NAD） biosynthesis, including synthesis from aspartate via the de novo pathway and from nicotinate （NA） via the Preiss-Handler pathway, is conserved in land plants. Diverse spe-cies of NA conjugates, which are mainly involved in NA detoxification, were also found in all tested land plants. Among these conjugates, MeNA （NA methyl ester） has been widely detected in angiosperm plants, although its physiological function and the underlying mechanism for its production in planta remain largely unknown. Here, we show that MeNA is an NAD precursor undergoing more efficient long-distance trans-port between organs than NA and nicotinamide in Arabidopsis. We found that Arabidopsis has one meth- yltransferase （designated AtNaMT1） capable of catalyzing carboxyl methylation of NA to yield MeNA and one methyl esterase （MES2） predominantly hydrolyzing MeNA back to NA. We further uncovered that the transfer of [^14C]MeNA from the root to leaf was significantly increased in both MES2 knockdown and NaMTl-overexpressing lines, suggesting that both NaMT1 and MES2 fine-tune the long-distance transport of MeNA, which is ultimately utilized for NAD production. Abiotic stress （salt, abscisic acid, and mannitol） treatments, which are known to exacerbate NAD degradation, induce the expression of NaMT1 but sup-press MES2 expression, suggesting that MeNA may play a role in stress adaption. Collectively, our study indicates that reversible methylation of NA controls the biosynthesis of MeNA in Arabidopsis, which pre-sumably functions as a detoxification form of free NA for efficient long-distance transport and eventually NAD production especially under abiotic stress, providing new insights into the relationship between NAD biosynthesis and NA conjugation in plants.
基金supported partially by the Kentucky Tobacco Research and Development Center(KTRDC),University of Kentucky.
文摘The evolutionarily conserved mitogen-activated protein kinase(MAPK)cascades relay extracellular signals into cells,triggering a variety of cellular responses.We previously revealed NtMPK4 as a positive regulator of nicotine biosynthesis;however,its upstream regulation remains unclear.Here,we characterized a MAPK cascade,comprising NtMEKK1b,NtMPKK2a,and NtMPK4,that promotes nicotine biosynthesis.This signaling module transduces external cues,including jasmonate and pathogen elicitors such as flg22,into post-translational modifications that enhance transcriptional activity and pathway gene expression.NtMPKK2a physically interacts with and phosphorylates NtMPK4 in vivo,confirming its role as an upstream kinase.RNAi-mediated silencing of NtMPKK2a significantly reduced the expression of nicotine pathway genes and decreased nicotine accumulation,whereas induced-overexpression of NtMPKK2a upregulated nicotine pathway genes and increased nicotine contents in tobacco hairy roots.Overexpression of NtMPKK2a in tobacco cells enhanced the transactivation activity of a NIC2-locus Ethylene Response Factor NtERF221 on Putrescine N-methyltransferase(NtPMT)promotor,further supporting its role in promoting nicotine biosynthesis.Furthermore,we identified NtMEKK1b,a tobacco MEKK that interacts with NtMAPKK2a in yeast cells.Knock-down of NtMEKK1b in transgenic tobacco plants attenuated the expression of nicotine pathway genes and reduced nicotine contents,whereas induced-overexpression of NtMEKK1b upregulated gene expression and nicotine accumulation.Our findings uncover a previously uncharacterized MAPK cascade module,NtMEKK1b-NtMPKK2a-NtMPK4,that regulates nicotine biosynthesis,highlighting the importance of posttranslational regulation in nicotine biosynthesis.
基金supported by ANID-FONDECYT 1200908(to JF),ANID-FONDECYT 1211082 and 1250856(to GEY)by the Millennium Nucleus for the Study of Pain NCN19_038(Mi Nu SPain)(to GEY)funded by the ANID scholarship 21201176。
文摘Numerous pathological states of the nervous system involve alterations in neuronal excitability and synaptic dysfunction,which depend on the function of ion channels.Due to their critical involvement in health and disease,the search for new compounds that modulate these proteins is still relevant.Traditional medicine has long been a rich source of neuroactive compounds.For example,the indigenous Mapuche people have used the leaves and bark of the Drimys winteri tree for centuries to treat various diseases.Consequently,several studies have investigated the biological effects of compounds in Drimys winteri,highlighting sesquiterpenes such asα-humulene,drimenin,polygodial,andα-,β-,γ-eudesmol.However,there is currently no literature review focusing on the ability of these sesquiterpenes to modulate ion channels.This review summarizes the current knowledge about neuroactive compounds found in Drimys winteri,with special emphasis on their direct actions on neuronal ion channels.Several Drimys winteri sesquiterpenes modulate a diverse array of neuronal ion channels,including transient receptor potential channels,gamma-aminobutyric acid A receptors,nicotinic acetylcholine receptors,and voltage-dependent Ca^(2+)and Na^(+)channels.Interestingly,the modulation of these molecular targets by Drimys winteri sesquiterpenes correlates with their therapeutic actions.The promiscuous pharmacological profile of Drimys winteri sesquiterpenes suggests they modulate multiple protein targets in vivo,making them potentially useful for treating complex,multifactorial diseases.Further studies at the molecular level may aid in developing multitargeted drugs with enhanced therapeutic effects.
文摘It is a common misconception that e-cigarettes are safer than tobacco smoking,given their adverse cardiopulmonary effects,habituation,and the fact that it is only a fashion based manifestation to sell and use them.Therefore,the use of e cigarettes should not be encouraged as an alternative and pragmatic measure should be taken to profess this agenda.
文摘Imidacloprid,a neonicotinoid insecticide,is widelyused in agriculture as a safer alternative to highly toxicorganophosphates.It targets nicotinic acetylcholinereceptors in pests and is generally low in toxicity tohumans.However,large ingestions can cause severe,life-threatening complications,with no establishedtreatment protocols.Though rarely fatal,imidaclopridpoisoning is increasingly reported in agricultural regions,particularly in Southeast Asia,with most cases involvingsuicide attempts.
基金Supported by the Science and Technology Project of Guizhou Provincial Company,CNTC(2023XM22)Science and Technology Program of Science and Technology Department of Guizhou Province(QKHPTRC-GCC[2023]067,QKHJC-ZK[2022]YB288)+2 种基金Science and Technology Project of Bijie City of Guizhou Provincial Tobacco Company(2021520500240228)Science and Technology Project of Zunyi City of Guizhou Provincial Tobacco Company(2023XM06)Science and Technology Project of Guizhou Academy of Tobacco Science(GZYKY2022-02).
文摘[Objectives]To elucidate the impact of different drying temperatures on the biochemical profile of tobacco(Nicotiana tabacum L.)leaves,the chemical constituents and ultrastructure of Yunyan 87 leaves subjected to different curing temperature settings.[Methods]Near-infrared spectroscopy techniques were utilized to analyze tobacco leaf samples,comparing the changes in chemical constituents at different curing temperatures.[Results]The CK treatment resulted in lower concentrations of nicotine,total nitrogen,chlorine,potassium,and starch,while simultaneously enhancing the levels of total sugar,reducing sugar,and protein.In comparison to the T treatment,the CK treatment appropriately altered the cell structure,reducing the content of cell wall substances.[Conclusions]These findings suggest that low-temperature curing at 44℃during the color-fixing stage is beneficial for improving the quality of tobacco leaves.
文摘To investigate the differences in physical and chemical indicators of tobacco stems from different parts of the‘Honghuadajinyuan’variety in the Dali tobacco-growing area,a comparative analysis of these indicators was conducted.The results showed that in terms of physical indicators,the tobacco stem length and content in middle part were significantly higher than those in other parts;the filling value of cut stems in upper part was significantly better than that in the middle and lower parts.In terms of chemical compositions,the content of total sugar and reducing sugar in middle part were the highest;the content of nicotine,total chlorine,and chlorine in upper part were the highest;the difference between total sugar and reducing sugar,sugar-to-nicotine ratio,nitrogen-to-nicotine ratio,and potassium-to-chlorine ratio in middle part were the best;and the potassium content in lower part was significantly higher than that in other parts.Correlation analysis showed that equilibrium moisture content was significantly positively correlated with total nitrogen content.Among them,equilibrium moisture content in upper part was positively correlated with nicotine content,and equilibrium moisture content in middle part was positively correlated with potassium and chlorine content.In addition,the filling value of cut stems in lower part was positively correlated with reducing sugar and total nitrogen content,while the filling value of cut stems in all parts was negatively correlated with the difference between total sugar and reducing sugar,sugar-to-nicotine ratio,and nitrogen-to-nicotine ratio.
基金the National Agency for Scientific and Technological Promotion(ANPCyT)[2015-2396]ORT Argentina’s 2021-2025 Scientific Research Internship Program.
文摘Background:Triple-negative(TN)breast cancer,the most aggressive subtype of breast cancer,is usually treated with high doses of paclitaxel(PX),which induces resistance.To prevent this adverse effect,metronomic chemotherapy based on administering low doses of PX plus carbachol(Carb),a muscarinic acetylcholine receptor(mAChR)agonist,has emerged as an alternative.Other acetylcholine receptors also present in breast tissue are nicotinic ones.When activated by nicotine(Nic),these receptors can decrease the effectiveness of conventional chemotherapy.However,whether metronomic chemotherapy with PX and Carb is affected by Nic has not yet been described.This study aimed to determine the efficacy of metronomic chemotherapy with PX and Carb in human breast tumor MDA-MB-231 cells in the presence or absence of Nic and assess the intermediaries involved.Methods:Cell viability and proliferation were determined using colorimetric assays with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)and trypan blue.Nitrite levels in cell supernatant were determined using Griess reagent.The expression of proteins was determined by western blot assays.Apoptosis/necrosis and the proportion of cancer stem cells(CSC)were determined by flow cytometry.Mammosphere-forming units were determined with anchorage-free growth assays.Results:The metronomic chemotherapy combining PX and Carb effectively inhibited the viability of TN MDA-MB-231 cells in the presence and absence of Nic.These effects were mediated by the activation of mAChRs,triggering signaling pathways dependent on several kinases.These mediators induce increased expression of the inducible isoform of nitric oxide synthase(NOS).Only the inducible and endothelial isoforms were expressed in these cells,and their activity was increased by the metronomic chemotherapy with PX and Carb.Nitric oxide(NO),a product of NOS activity,may contribute to the observed increase in apoptosis.We also observed an increased sensitivity to PX in the residual cells after the metronomic chemotherapy,as well as a decrease in mammosphere-forming units and CSC proportion.We also determined a decrease in the expression of stemness proteins such as ATP-binding cassette super-family G member 2(ABCG2),sex-determining region Y-box 2(SOX2),octamer-binding transcription factor 4(OCT-4),and Nanog.Conclusions:Metronomic chemotherapy combining PX with Carb was selective for MDA-MB-231 cells and increased their sensitivity to conventional chemotherapy in the presence and absence of Nic,indicating that it could be a useful neoadjuvant strategy for the treatment of TN breast tumors.
基金supported by grants from the Natural Science Foundation of Hunan Province(2022JJ70037 and 2022JJ40402)the National Natural Science Foundation of China(82472220 and 82002074)+1 种基金the Natural Science Foundation of Guangdong Province(2023A1515010267,2023A1515012665 and 2024A1515010073)the China International Medical Foundation Cerebrovascular Disease Youth Innovation Fund(Z-2016-20-2201).
文摘BACKGROUND:While theα7 nicotinic acetylcholine receptor(α7 nAChR)is implicated in sepsis-associated encephalopathy(SAE),its pathophysiological contributions require further investigation.METHODS:SAE was induced in mice via cecal ligation and puncture(CLP),and microglia were treated with lipopolysaccharide(LPS).PHA-543613(anα7 nAChR agonist)was used to activateα7 nAChR.To study the role ofα7 nAChR in mitophagy and pyroptosis,caspase-1-deficient mice and PTEN-induced kinase 1(PINK1)small interfering RNA(siRNA)were used.Cognitive function,cerebral oxygen extraction ratio(CERO2),and brain tissue oxygen pressure(PbtO2)were measured.Blood-brain barrier(BBB)integrity was evaluated via Evan’s blue staining.Mitophagy,pyroptosis,and cytokine levels were analyzed via Western blotting and immunofl uorescence.RESULTS:CLP or LPS treatment signifi cantly down-regulatedα7 nAChR protein expression in microglia.The administration of PHA-543613 to activateα7 nAChR not only restored its expression post-sepsis,but also notably decreased BBB permeability and mitigated cognitive deficits.Bothα7 nAChR activation and caspase-1 knockout effectively suppressed microglial pyroptosis.The activation ofα7 nAChR also promoted mitophagy in microglia.This led to an amelioration of brain tissue hypoxia,as shown by elevated PbtO2 and reduced CERO2 levels.The suppression of microglial pyroptosis byα7 nAChR was counteracted when mitophagy was inhibited through the siRNA-mediated silencing of PINK1.CONCLUSION:The activation ofα7 nAChR reduces pyroptosis by enhancing microglial mitophagy,thereby mitigating SAE.
基金supported by the National Natural Science Foundation of China(U22A20362,U23A20407,82030111,82104301)Hubei Province’s Outstanding Medical Academic Leader program.
文摘Nicotine,ethanol,and caffeine are the most common exogenous substances in the men’s living environment,but their effects on the cartilage quality in the father and offspring have not been reported.According to the average daily intake of adult men,we constructed a male rat model of paternal mixed exposure(PME)to low-dose nicotine(0.1 mg/(kg·day)),ethanol(0.5 g/(kg·day)),and caffeine(7.5 mg/(kg·day))for 8 weeks.Then,the male rats mated with normal female rats to obtain offspring.The results showed that PME reduced the cartilage quality of paternal and offspring rats.Among them,the paternal cartilage was damaged by enhancing matrix degradation,while the offspring cartilage was damaged by reducing matrix synthesis.The cartilage damage in male offspring rats was more evident than in female offspring.It was further confirmed that differential GC regulation mechanisms were the main reasons for the intergenerational differential damage of paternal/offspring cartilage quality caused by PME.In addition,the androgen receptor(AR)and estrogen receptor beta(ERβ)mediated the sex difference of PME-induced fetal cartilage dysplasia by affecting the binding degree of GR/P300.This study provided a theoretical and experimental basis for guiding male healthy lifestyle and exploring early prevention and treatment strategies for paternal diseases.
基金supported by National Natural Science Foundation of China(No.32160615).
文摘Background Verticillium dahliae,a soil-borne fungi,can cause Verticillium wilt,and seriously diminish the yield and quality of cotton.However,the pathogenic mechanism of V.dahliae is complex and not clearly understood at the moment.This study aimed to identify the high-affinity nicotinic acid transporter genes in V.dahliae.The gene expression profiles in V.dahliae following sensing of root exudates from susceptible and resistant cotton varieties were analyzed.The function of VdNAT1 in the pathogenic process of V.dahliae was studied using the tobacco rattle virus(TRV)-based host-induced gene silencing(HIGS)technique.Results Eight high-affinity nicotinic acid transporter genes were identified from V.dahliae through the bioinformatics method.Each protein contains a conserved major facilitator superfamily(MFS)domain,which belongs to the MFS superfamily.Evolutionary relationship analysis revealed that all 8 genes belong to the anion:cation symporter(ACS)subfamily.All proteins have transmembrane domains,ranging from 7 to 12.The expression levels of most VdNAT genes were significantly increased after induction by root exudates from susceptible cotton varieties.Silencing VdNAT1 gene by HIGS significantly inhibited the accumulation of fungal biomass in cotton plants,and alleviated the disease symptoms of cotton.Conclusions Eight VdNAT genes were identified from V.dahliae,and most VdNAT genes was up-regulated after induced by root exudates from susceptible cotton variety.In addition,VdNAT1 is required for the pathogenicity of V.dahliae.Overall,these findings will facilitate the pathogenic molecular mechanism of V.dahliae and provide candidate genes.
基金Supported by the Research on Biofermentation Technology of Domestic Cigar Tobacco(202115010534-JS-178)(2021)。
文摘Nicotine,also known as nicotinic norephedrine,is one of the main alkaloids present in tobacco plants.In recent years,due to the increase in tobacco production and smoking population,the environmental and health issues caused by nicotine have become increasingly severe.Traditional methods have proven ineffective in efficiently degrading residual nicotine.To address this issue,scientists both domestically and internationally have turned to biodegradation methods to tackle the environmental and health problems caused by residual nicotine.In this study,an enrichment method was used to screen bacteria with nicotine-degrading capabilities from the soil of tobacco planting sites at the Tobacco Research Institute of Heilongjiang in Bin County,Harbin City.Through phenotypic observations and 16S rDNA identification,a bacterial strain identified as Pseudomonas hunanensis MGJ-2 was isolated,capable of utilizing nicotine as a carbon and nitrogen source for growth.High-performance liquid chromatography(HPLC)-1 analysis revealed that within 25 h,strain MGJ-2 could degrade nicotine 500 mg·L^(-1) with an efficiency exceeding 99.9%.Strain MGJ-2 was applied to tobacco,and after 15 days of incubation and fermentation,it degraded 10.57%of nicotine in tobacco.Overall,the discovery of strain MGJ-2 enriched the resources of nicotine-degrading strains.Its remarkable biodegradation performance held immense potential for future biodegradation of nicotine in tobacco.
文摘Nicotinic acetylcholine receptors (nAChRs) play a significant role in excitatory synaptic transmission in insects and are the target for chloronicotinyl and nereistoxin insecticides.In recent years,Chilo suppressalis,an economically important pest of rice,developed high resistance against monosultap,a nereistoxin insecticide acting on nAChR.In order to reveal the hypothesized target insensitive mechanism,studies on the molecular property of nAChR from Chilo suppressalis are required.In this study,the full length cDNA of nAChR α subunit from this pest was cloned by RT-PCR.Sequence analysis shows that it is a novel nAChR α subunit,which was named as Cs α 1(Genbank accession No.AF418987).It contains 1?997?bp nucleotides and involves an open reading frame (ORF) encoding a mature protein of 509 amino acids excluding a signal peptide of 24 amino acids.The deduced amino acid sequence was 52%-94% identical to the reported insect nAChR genes.
