The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers ...The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.展开更多
Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu cop...Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu copolymer under microwave irradiation.The influence of reaction parameters on conversion,molecular weight and inhibition of CaCO3 precipitation was investigated Infra-red.(IR), 1H nuclear magnetic resonance( 1H NMR)and 13C nuclear magnetic resonance( 13C NMR)spectroscopies were used to characterize the copolymer.The results show that copolymerization of aspartic acid and glutamic acid is catalyzed by a small amount of phosphorous acid (H3PO4)in solvent,the product conversion is 98.05%under the following conditions:the molar ratio of glutamic acid to reactant[Glu/(Asp+Glu)]is 0.3 and that of catalyst(Cat)to reactant[Cat/(Glu+Asp)]is 0.05(0.65ml H3PO4),the volume of solvent dimethylformamide is 16ml,the microwave power used is 720W and the reaction for 3 min.The weight average molecular weight of copolymer synthesized under these conditions is 2709 and the inhi- bition rate for CaCO3 is 97.75%.展开更多
In this study,the preparation of a new kind of magnetic and luminescent Fe3O4/CdTe nanocomposites was demonstrated. Superparamagnetic Fe3O4 nanoparticles were first synthesized by hydrothermal coprecipitation of ferri...In this study,the preparation of a new kind of magnetic and luminescent Fe3O4/CdTe nanocomposites was demonstrated. Superparamagnetic Fe3O4 nanoparticles were first synthesized by hydrothermal coprecipitation of ferric and ferrous ions,followed by the modification of their surfaces with tetramethylammonium hydroxide（TMAOH） and the chemical activation with aspartic acid.The surface-modified Fe3O4 nanoparticles were then covalently coated with CdTe quantum dots（QDs）,which were modified with mercaptoacetic acid（MPA）,to form the Fe3O4/CdTe magnetic and luminescent nanocomposites through the coordination of the amino groups on the surfaces of Fe3O4 and the carboxyl groups on CdTe QDs.The structure and properties of as-synthesized nanocomposites were characterized.It was indicated that the nanocomposites possessed structure with an average diameter of 40- 50 nm,yellow-green emission feature and room temperature ferro-magnetism.Both the fluorescence and UV-vis absorption spectra of the nanocomposites showed a blue shift comparing with those of CdTe QDs.The mechanism of the blue shift was presented.The nanocomposites retained the ferromagnetic property with a saturation magnetization of 8.9 emu/g.展开更多
Total RNA was isolated from mycelium of T. harzianum by Total RNA extraction kit, and two clear bands of rRNA （28S and 18S） were observed in agarose electrophoresis. By joining the 3＇end sequence with the known SA7...Total RNA was isolated from mycelium of T. harzianum by Total RNA extraction kit, and two clear bands of rRNA （28S and 18S） were observed in agarose electrophoresis. By joining the 3＇end sequence with the known SA76 EST from cDNA library of T. harzianum, a full-length cDNA sequence of 2019bp was obtained, whose open reading frame contained 1593bp, a stop codon TAA, a 5＇untranslated region （5＇UTR） of 266bp, a 3＇untranslated region （3＇UTR） of 201bp, and poly （A） 29 encoded a protein of 530 amino acids, had a signal peptide. T. harzianum shared 53% identity of secreted aspartic proteinase gene with G. zeae, 37% with N. crassa and 36% with C. globosum. The full-length cDNA sequence of secreted aspartic proteinase gene from T. harzianum was cloned for the first time by using BD SMART RACE technique, which provides a foundation to obtain and validate functional genes of T. harzianum.展开更多
A biodegradable gene transfer vector, poly(ethylenimine)-grafted-poly[(aspartic acid)-co-lysine] has been developed by thermal polycondensation of aspartic acid and lysine, and branch poly(ethylenimine) (Mw less than ...A biodegradable gene transfer vector, poly(ethylenimine)-grafted-poly[(aspartic acid)-co-lysine] has been developed by thermal polycondensation of aspartic acid and lysine, and branch poly(ethylenimine) (Mw less than 600) was grafted to the backbone. The polymer was characterized by 1H NMR. It appeared lower cytotoxity compared to poly(ethylenimine) (25KDa), which was quantified by MTT assay. Electrophoresis indicated that the polymer could retardate DNA at N/P ratio 1.2-1.8 (w/w). Transfection efficiency of the complexes was studied in NT2 cell lines. It was 1.5 fold higher than molecular weight PEI (Mw = 25KDa).展开更多
A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding proper...A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.展开更多
Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the...Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the precursor, this study provides experimental evidence for serine formation in weak acidified aqueous solutions in the presence of iron, with exposure to sunlight, which simulates the natural conditions of the prebiotic aqueous environment. The resultant mixture is directly analyzed via desorption electrospray ionization mass spectrometry（ DESI-MS）, without any sample preseparation. The serine monomer is successfully detected as protonated molecules, giving a peak at m/z 106, which is confirmed by the MS/MS fragments. Protonated serine octamer（ m/z 841 ） is also observed with significant abundance in the MS spectra and is confirmed by the MS/MS data, which shows the formation of the serine octamer by a synthesized serine in the resultant mixture. It is also found that the serine octamer yielded equivalent abundance in the DESI mass spectra in a wide pH range（pH = 1-5 ）, and that existence of ferrous salt and sunshine are essential for the conversion of aspartic acid to serine in the acidic water solution.展开更多
The random copolymers of glutamic acid （LG） and aspartic acid （ASP）, poly（LG-co-ASP）, with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerizat...The random copolymers of glutamic acid （LG） and aspartic acid （ASP）, poly（LG-co-ASP）, with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerization with debenzylation. Ring opening copolymerizations of y：benzyl-L-glutamate N-carboxyanhydride （BLG-NCA） and β-benzyl-Laspartate N-carboxyanhydride （BLA-NCA） were carried out by using different amines including triethylamine （TEA）, diethylamine, n-hexylamine （NHA）, triphenylamine, diphenylamine or aniline as initiators. All the 6 amines were highly efficient to get well-defined poly（BLG-co-BLA） copolymers with designed compositions although the polymerizations proceeded via different mechanisms （normal amine mechanism or/and activated monomer mechanism）, which are based on chemical structure of amines. The molecular weights of poly（BLG-co-BLA） copolymers could be mediated by both TEA concentration and polymerization time. Then, debenzylation ofpoly（BLG-co-BLA） copolymers was conducted to prepare the corresponding hydrophilic random eopolymers of poly（LG-co-ASP） with a-subunit structure in ASP structural units. The contents of LG structural units in poly（LG-co-ASP） copolymers matched with those of BLG-NCA in NCA-monomer feeds in ring opening copolymerizations initiated by NHA or TEA and were closed to the theoretical line. The diblock copolymer of poly（BLG-b-BLA） could also be synthesized via living NCA ring opening copolymerization by sequential addition of BLG- NCA and BLA-NCA.展开更多
Based on a mechanism analogous to the serine/threonine ligation, the aspartic acid ligation, which is facilitated by the γ-amino alcohol based ligation and oxidation, is developed and applied to the synthesis of cycl...Based on a mechanism analogous to the serine/threonine ligation, the aspartic acid ligation, which is facilitated by the γ-amino alcohol based ligation and oxidation, is developed and applied to the synthesis of cyclic peptides. The γ-hydroxyl group triggers the ring-chain tautomerization via a 6-endo-trig process,while the δ-hydroxyl group facilitates the oxidative cleavage of the vicinal diol to give carboxylic acid.展开更多
The preparation of the a carboxyl 9-fluorenylmethyl(FM) ester of Boc-aspartic acid is described.This new protected amino acid linked to the polymeric support by βcarboxyl group offers a convenient strategy for the sy...The preparation of the a carboxyl 9-fluorenylmethyl(FM) ester of Boc-aspartic acid is described.This new protected amino acid linked to the polymeric support by βcarboxyl group offers a convenient strategy for the synthesis of head-to-tail cyclopeptides while the peptides remained attached to the polymeric support.展开更多
The β-carboxylic group plays an important role in the peptide formation,esterification and the ester exchange at the phosphoryl group of N-phosphorylated aspartic acid.
Poly(aspartic acid-itaconic acid) copolymer was synthesized from aspartic acid(Asp) and itaconic acid(Ita) under microwave irradiation. The effects of microwave power, microwave irradiation time, molar ratio of itacon...Poly(aspartic acid-itaconic acid) copolymer was synthesized from aspartic acid(Asp) and itaconic acid(Ita) under microwave irradiation. The effects of microwave power, microwave irradiation time, molar ratio of itaconic acid and aspartic acid, catalyst type, catalyst and organic solvent content on copolymer yield, and the performance for inhibition of CaCO_3 fouling were investigated. It was found that the product yield achieved a highest record of 95% when the amount of catalyst Na H_2PO_4 was 0.012 mol, the amount of organic solvent propylene carbonate was 16 m L, the molar ratio of Asp/Ita was 3:1, the microwave output power was 1200 W and the irradiation time was 5.5 min. And the product performance for inhibition of calcium carbonate also reached a highest value of 94.38%. Structural characterization of the product showed that the product was the aspartic acid-itaconic acid copolymer.展开更多
A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition ...A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition of gold nano-particles on the glassy carbon electrode. The resulting poly (aspartic acid)-nanogold modified electrode (PAA- nano-Au/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectros-copy (EIS). A higher catalytic activity was obtained to electrocatalytic oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) due to the enhanced peak current and well-defined peak separations compared with three, bare GCE, PAA/GCE and nano-Au/GCE. Simultaneous determination of DA, AA, and UA were studied by voltammetry. The linear range of 5.0 × 10-7 - 1.0 × 10-4 M for DA, 5.0 × 10-6 - 2.0 × 10-3 M for AA and 5.0 × 10-6 - 1.0 × 10-3 M for UA was obtained. The detection limit was calculated for DA, AA and UA as being 6.5 × 10-8 M, 5.6 × 10-7 M and 3.0 × 10-7 M, respectively (S/N = 3). The practical application of the present modified electrode was demonstrated by the determination of DA, AA and UA in calf serum and fetal calf serum samples.展开更多
The aim of this study was to prepare diphenhydramine hydrochloride (DPH)-loaded orally fast-disintegrating mini-tablets (OFDMTs) containing either L-aspartic acid (Asp) or L-glutamic acid (Glu) as bitterness-suppressa...The aim of this study was to prepare diphenhydramine hydrochloride (DPH)-loaded orally fast-disintegrating mini-tablets (OFDMTs) containing either L-aspartic acid (Asp) or L-glutamic acid (Glu) as bitterness-suppressant, to characterize the prepared tablets and to evaluate their bitterness under conditions mimicking those of the oral cavity. The preparation of five formulation batches of the OFDMTs involved mixing DPH, with or without two different concentrations of Asp or Glu, and a premix containing a disintegrating agent. When all ingredients were well mixed, the mixture was directly compacted to form small (4 mm diameter) DPH-loaded OFDMTs. There were only small differences between the tablets with respect to mass, diameter, width and hardness. The disintegration times of the five formulation batches of DPH-loaded OFDMTs were measured using the OD-mate, a disintegration test apparatus in which conditions resemble those of the oral cavity. The disintegration times were all within 10 s of exposure to a medium representing the inside of the oral cavity. Rapid release profiles were observed for DPH, Asp and Glu in these dissolution tests. The taste sensor outputs of samples taken at different times (5 - 30 s) from the dissolution test solutions of the four DPH-loaded OFDMTs containing Asp or Glu were significantly inhibited compared with those of control DPH-loaded OFDMT. These results suggest that the inclusion of Asp or Glu in DPH-loaded OFDMTs is sufficient to mask bitterness in the oral cavity for the first 30 s after the tablet is placed in the mouth. It is anticipated that swallowing will have taken place within 30 s.展开更多
Objective:To investigate the anti-liver cancer effects and aspartic acid(Asp)-related action mechanism of Euphorbia fischeriana Steud.(LD).Methods:The mice model of liver cancer was established by injection of H22 cel...Objective:To investigate the anti-liver cancer effects and aspartic acid(Asp)-related action mechanism of Euphorbia fischeriana Steud.(LD).Methods:The mice model of liver cancer was established by injection of H22 cells.After 5 days,mice were randomly divided into model group,sorafenib group(20 mg/kg),LD high-dose(LDH,1.36 g/kg) group,LD medium-dose(LDM,0.68 g/kg) group,and LD low-dose(LDL,0.34 g/kg)group,10 mice each group.Drugs were intragastrically administered to the mice once daily for 10 days,respectively.Body weight,tumor size and tumor weight were recorded.Hepatic index was calculated.Pathological changes of liver cancer tissues were evaluated by hematoxylin and eosin staining and TUNEL staining.Liquid chromatography-mass spectrometer was used to analyze different metabolites between the model and LDH groups.Results:After LD treatment,tumor weight,tumor size and hepatic index were reduced compared with the model group.Necrocytosis and karyorrhexis of tumor cells were found.Moreover,61 differential metabolites(18 up-regulated,43 down-regulated) were affirmed and 20 pathways of KEGG(P<0.05) were gotten.In addition,Bel-7402,HepG2 and H22 cell viabilities were significantly increased after adding Asp into the medium.And then,the cell proliferation effect induced by Asp was ameliorated by LD.Conclusion:The anti-liver cancer efficacy of LD extract was validated in H22 mice model,and inhibition of Asp level might be the underlying mechanism.展开更多
Light emitting diode(LED-UV)/chlorine disinfection can replace UV/chlorine disinfection in wastewater treatment plants and water supply plants.Halonitromethanes(HNMs)are a class of novel nitrogenous disinfection by-pr...Light emitting diode(LED-UV)/chlorine disinfection can replace UV/chlorine disinfection in wastewater treatment plants and water supply plants.Halonitromethanes(HNMs)are a class of novel nitrogenous disinfection by-products,which are characterized by higher cytotoxicity and genotoxicity than regulated disinfection by-products.Herein,the impact factors and pathways of HNMs formation from aspartic acid(ASP)were investigated during LED-UV_(265)/chlorine disinfection.The results showed that three types of chlorinated-HNMs(Cl-HNMs)were found during LED-UV265/chlorine disinfection,and their concentrations increased first and then declined as the reaction progressed.Cl-HNMs yields increased with increasing LED-UV_(265)intensity,free chlorine dosage,and ASP concentration,which declined with increasing pH(6.0–8.0).Meantime,the important impact of the coexisting ions contained in water matrices on HNMs formation from ASP was observed during LED-UV_(265)/chlorine disinfection.It was found that copper ions(Cu^(2+))promoted Cl-HNMs formation.Furthermore,when bromide(Br–)appeared during LED-UV265/chlorine disinfection,nine types of HNMs were detected simultaneously.Moreover,Br–not only converted Cl-HNMs toward brominated(chlorinated)-HNMs and brominated-HNMs but also showed a marked effect on HNMs concentrations and species.Subsequently,the possible pathways of HNMs formation from ASP were proposed during LED-UV_(265)/chlorine disinfection.At last,it was proved that the formation trends of HNMs obtained in the real waters were similar to those in simulated waters.This work elaborated on the influence factors and pathways of HNMs formation,which is conducive to controlling the HNMs produced during LED-UV_(265)/chlorine disinfection.展开更多
Plants secrete defense molecules into the extracellular space (the apoplast) to combat attacking microbes. However, the mechanisms by which successful pathogens subvert plant apoplastic immunity remain poorly understo...Plants secrete defense molecules into the extracellular space (the apoplast) to combat attacking microbes. However, the mechanisms by which successful pathogens subvert plant apoplastic immunity remain poorly understood. In this study, we show that PsAvh240, a membrane-localized effector of the soybean pathogen Phytophthora sojae, promotes P. sojae infection in soybean hairy roots. We found that PsAvh240 interacts with the soybean-resistant aspartic protease GmAP1 in planta and suppresses the secretion of GmAP1 into the apoplast. By solving its crystal structure we revealed that PsAvh240 contain six a helices and two WY motifs. The first two a helices of PsAvh240 are responsible for its plasma membrane-localization and are required for PsAvh240's interaction with GmAP1. The second WY motifs of two PsAvh240 molecules form a handshake arrangement resulting in a handshake-like dimer. This dimerization is required for the effector's repression of GmAP1 secretion. Taken together, these data reveal that PsAvh240 localizes at the plasma membrane to interfere with GmAP1 secretion, which represents an effective mechanism by which effector proteins suppress plant apoplastic immunity.展开更多
BACKGROUND There is a lack of clinical evidence on the efficacy and safety of transitioning from a thrice-daily pre-mixed insulin or basal-prandial regimen to insulin degludec/aspart(IDegAsp)therapy,with insufficient ...BACKGROUND There is a lack of clinical evidence on the efficacy and safety of transitioning from a thrice-daily pre-mixed insulin or basal-prandial regimen to insulin degludec/aspart(IDegAsp)therapy,with insufficient data from the Chinese population.AIM To demonstrate the efficacy,safety,and treatment satisfaction associated with the transition to IDegAsp in type 2 diabetes mellitus(T2DM).METHODS In this 12-week open-label,non-randomized,single-center,pilot study,patients with T2DM receiving thrice-daily insulin or intensive insulin treatment were transitioned to twice-daily injections of insulin IDegAsp.Insulin doses,hemoglobin A1c(HbA1c)levels,fasting blood glucose(FBG),hypoglycemic events,a Diabetes Treatment Satisfaction Questionnaire,and other parameters were assessed at baseline and 12-weeks.RESULTS This study included 21 participants.A marked enhancement was observed in the FBG level(P=0.02),daily total insulin dose(P=0.03),and overall diabetes treatment satisfaction(P<0.01)in the participants who switched to IDegAsp.There was a decrease in HbA1c levels(7.6±1.1 vs 7.4±0.9,P=0.31)and the frequency of hypoglycemic events of those who switched to IDegAsp decreased,however,there was no statistically significant difference.CONCLUSION The present findings suggest that treatment with IDegAsp enhances clinical outcomes,particularly FBG levels,daily cumulative insulin dose,and overall satisfaction with diabetes treatment.展开更多
In order to better understand the mechanism of NO_(x)and N_(2)Oprecursors(NH_(3)and HCN)from aspartic acid(Asp)pyrolysis,decomposition reaction networks resulting in the generation of NH_(3)and HCN were investigated b...In order to better understand the mechanism of NO_(x)and N_(2)Oprecursors(NH_(3)and HCN)from aspartic acid(Asp)pyrolysis,decomposition reaction networks resulting in the generation of NH_(3)and HCN were investigated by employing density function theory methods.After several pathways were analyzed in detail,two series of pyrolytic reactions containing three possible pathways were proposed.All the reactants,transition states,intermediates and products were optimized,also the electronic properties on these crucial points were discussed,which shows that Cαacts as the most active site to initiate the pyrolysis reaction,where the direct Cα-Cβbond breakage,due to the atomic charge population of repulsion,led to one key route for the generation of HCN,and the transfer of Hαfrom Cαto Cβresulting in another key route for the generation of HCN,while the transfer of Hαfrom Cαto N atom of Asp resulting in the key route for the generation of HN3.Further,the kinetic analysis based on speed control method in each key reaction pathway was conducted to further compare the generation of HCN and NH_(3)under various temperatures.The above results are in accordance with the related experimental results.展开更多
BACKGROUND This case report describes a protocol developed by Danaun Medical Clinic for the introduction of a pioneering intervention comprising intravenous human placen-tal extract(HPE)therapy to improve the liver fu...BACKGROUND This case report describes a protocol developed by Danaun Medical Clinic for the introduction of a pioneering intervention comprising intravenous human placen-tal extract(HPE)therapy to improve the liver function of patients with chronic liver disease(CLD).CASE SUMMARY This study involved data from patients whose chief complaint was reduced quality of life attributable to CLD.The new treatment approach resulted in improvements in the liver function and fatty liver of 30 patients with CLD.Im-provements were observed using abdominal ultrasonography.Unlike traditional methods,this protocol provided more sustainable and meaningful results.Treat-ment with 10 mL of HPE administered intravenously once or twice per week significantly improved liver function.The observed improvements in fatty liver and liver function suggest the utility of this approach for the management of patients with CLD.CONCLUSION This case series highlights the potential of innovative treatments for patients with CLD that could improve the quality of life of the patients.展开更多
文摘The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.
基金Supported by Harbin Key Technologies R&D Program(No.2003AA4CS123).
文摘Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu copolymer under microwave irradiation.The influence of reaction parameters on conversion,molecular weight and inhibition of CaCO3 precipitation was investigated Infra-red.(IR), 1H nuclear magnetic resonance( 1H NMR)and 13C nuclear magnetic resonance( 13C NMR)spectroscopies were used to characterize the copolymer.The results show that copolymerization of aspartic acid and glutamic acid is catalyzed by a small amount of phosphorous acid (H3PO4)in solvent,the product conversion is 98.05%under the following conditions:the molar ratio of glutamic acid to reactant[Glu/(Asp+Glu)]is 0.3 and that of catalyst(Cat)to reactant[Cat/(Glu+Asp)]is 0.05(0.65ml H3PO4),the volume of solvent dimethylformamide is 16ml,the microwave power used is 720W and the reaction for 3 min.The weight average molecular weight of copolymer synthesized under these conditions is 2709 and the inhi- bition rate for CaCO3 is 97.75%.
基金supported by the National Natural Science Foundation of China(Nos.20345006 and 20575043)
文摘In this study,the preparation of a new kind of magnetic and luminescent Fe3O4/CdTe nanocomposites was demonstrated. Superparamagnetic Fe3O4 nanoparticles were first synthesized by hydrothermal coprecipitation of ferric and ferrous ions,followed by the modification of their surfaces with tetramethylammonium hydroxide（TMAOH） and the chemical activation with aspartic acid.The surface-modified Fe3O4 nanoparticles were then covalently coated with CdTe quantum dots（QDs）,which were modified with mercaptoacetic acid（MPA）,to form the Fe3O4/CdTe magnetic and luminescent nanocomposites through the coordination of the amino groups on the surfaces of Fe3O4 and the carboxyl groups on CdTe QDs.The structure and properties of as-synthesized nanocomposites were characterized.It was indicated that the nanocomposites possessed structure with an average diameter of 40- 50 nm,yellow-green emission feature and room temperature ferro-magnetism.Both the fluorescence and UV-vis absorption spectra of the nanocomposites showed a blue shift comparing with those of CdTe QDs.The mechanism of the blue shift was presented.The nanocomposites retained the ferromagnetic property with a saturation magnetization of 8.9 emu/g.
基金This paper was supported by Development Program (863) of China (No. 2003AA241140)
文摘Total RNA was isolated from mycelium of T. harzianum by Total RNA extraction kit, and two clear bands of rRNA （28S and 18S） were observed in agarose electrophoresis. By joining the 3＇end sequence with the known SA76 EST from cDNA library of T. harzianum, a full-length cDNA sequence of 2019bp was obtained, whose open reading frame contained 1593bp, a stop codon TAA, a 5＇untranslated region （5＇UTR） of 266bp, a 3＇untranslated region （3＇UTR） of 201bp, and poly （A） 29 encoded a protein of 530 amino acids, had a signal peptide. T. harzianum shared 53% identity of secreted aspartic proteinase gene with G. zeae, 37% with N. crassa and 36% with C. globosum. The full-length cDNA sequence of secreted aspartic proteinase gene from T. harzianum was cloned for the first time by using BD SMART RACE technique, which provides a foundation to obtain and validate functional genes of T. harzianum.
文摘A biodegradable gene transfer vector, poly(ethylenimine)-grafted-poly[(aspartic acid)-co-lysine] has been developed by thermal polycondensation of aspartic acid and lysine, and branch poly(ethylenimine) (Mw less than 600) was grafted to the backbone. The polymer was characterized by 1H NMR. It appeared lower cytotoxity compared to poly(ethylenimine) (25KDa), which was quantified by MTT assay. Electrophoresis indicated that the polymer could retardate DNA at N/P ratio 1.2-1.8 (w/w). Transfection efficiency of the complexes was studied in NT2 cell lines. It was 1.5 fold higher than molecular weight PEI (Mw = 25KDa).
文摘A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.
基金Supported by the National Natural Science Foundation of China(No.20505003).
文摘Serine, one of the nonessential amino acids, is of principal interest because of its capability to form magic-number ionic clusters, which provide a remarkable preference for homochirality. With L-aspartic acid as the precursor, this study provides experimental evidence for serine formation in weak acidified aqueous solutions in the presence of iron, with exposure to sunlight, which simulates the natural conditions of the prebiotic aqueous environment. The resultant mixture is directly analyzed via desorption electrospray ionization mass spectrometry（ DESI-MS）, without any sample preseparation. The serine monomer is successfully detected as protonated molecules, giving a peak at m/z 106, which is confirmed by the MS/MS fragments. Protonated serine octamer（ m/z 841 ） is also observed with significant abundance in the MS spectra and is confirmed by the MS/MS data, which shows the formation of the serine octamer by a synthesized serine in the resultant mixture. It is also found that the serine octamer yielded equivalent abundance in the DESI mass spectra in a wide pH range（pH = 1-5 ）, and that existence of ferrous salt and sunshine are essential for the conversion of aspartic acid to serine in the acidic water solution.
基金National Natural Science Foundation of China(No.51173008)
文摘The random copolymers of glutamic acid （LG） and aspartic acid （ASP）, poly（LG-co-ASP）, with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerization with debenzylation. Ring opening copolymerizations of y：benzyl-L-glutamate N-carboxyanhydride （BLG-NCA） and β-benzyl-Laspartate N-carboxyanhydride （BLA-NCA） were carried out by using different amines including triethylamine （TEA）, diethylamine, n-hexylamine （NHA）, triphenylamine, diphenylamine or aniline as initiators. All the 6 amines were highly efficient to get well-defined poly（BLG-co-BLA） copolymers with designed compositions although the polymerizations proceeded via different mechanisms （normal amine mechanism or/and activated monomer mechanism）, which are based on chemical structure of amines. The molecular weights of poly（BLG-co-BLA） copolymers could be mediated by both TEA concentration and polymerization time. Then, debenzylation ofpoly（BLG-co-BLA） copolymers was conducted to prepare the corresponding hydrophilic random eopolymers of poly（LG-co-ASP） with a-subunit structure in ASP structural units. The contents of LG structural units in poly（LG-co-ASP） copolymers matched with those of BLG-NCA in NCA-monomer feeds in ring opening copolymerizations initiated by NHA or TEA and were closed to the theoretical line. The diblock copolymer of poly（BLG-b-BLA） could also be synthesized via living NCA ring opening copolymerization by sequential addition of BLG- NCA and BLA-NCA.
基金supported by the Research Grants Council (Nos. 17309616, C6009-15G) of Hong KongThe National Science Foundation of China (Nos. 21672180, 91753101)the Area of Excellence Scheme of the University of Grants Committee of Hong Kong (No. AoE/P-705/16)
文摘Based on a mechanism analogous to the serine/threonine ligation, the aspartic acid ligation, which is facilitated by the γ-amino alcohol based ligation and oxidation, is developed and applied to the synthesis of cyclic peptides. The γ-hydroxyl group triggers the ring-chain tautomerization via a 6-endo-trig process,while the δ-hydroxyl group facilitates the oxidative cleavage of the vicinal diol to give carboxylic acid.
文摘The preparation of the a carboxyl 9-fluorenylmethyl(FM) ester of Boc-aspartic acid is described.This new protected amino acid linked to the polymeric support by βcarboxyl group offers a convenient strategy for the synthesis of head-to-tail cyclopeptides while the peptides remained attached to the polymeric support.
文摘The β-carboxylic group plays an important role in the peptide formation,esterification and the ester exchange at the phosphoryl group of N-phosphorylated aspartic acid.
基金supported financially from the National Natural Science Foundation of China (Grant No. 51308211)the State Key Laboratory of Urban Water Resource and Environment (HIT) (Grant No. ES200903)the Fundamental Research Funds for the Central Universities (Grant No. 2015MS63)
文摘Poly(aspartic acid-itaconic acid) copolymer was synthesized from aspartic acid(Asp) and itaconic acid(Ita) under microwave irradiation. The effects of microwave power, microwave irradiation time, molar ratio of itaconic acid and aspartic acid, catalyst type, catalyst and organic solvent content on copolymer yield, and the performance for inhibition of CaCO_3 fouling were investigated. It was found that the product yield achieved a highest record of 95% when the amount of catalyst Na H_2PO_4 was 0.012 mol, the amount of organic solvent propylene carbonate was 16 m L, the molar ratio of Asp/Ita was 3:1, the microwave output power was 1200 W and the irradiation time was 5.5 min. And the product performance for inhibition of calcium carbonate also reached a highest value of 94.38%. Structural characterization of the product showed that the product was the aspartic acid-itaconic acid copolymer.
文摘A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition of gold nano-particles on the glassy carbon electrode. The resulting poly (aspartic acid)-nanogold modified electrode (PAA- nano-Au/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectros-copy (EIS). A higher catalytic activity was obtained to electrocatalytic oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) due to the enhanced peak current and well-defined peak separations compared with three, bare GCE, PAA/GCE and nano-Au/GCE. Simultaneous determination of DA, AA, and UA were studied by voltammetry. The linear range of 5.0 × 10-7 - 1.0 × 10-4 M for DA, 5.0 × 10-6 - 2.0 × 10-3 M for AA and 5.0 × 10-6 - 1.0 × 10-3 M for UA was obtained. The detection limit was calculated for DA, AA and UA as being 6.5 × 10-8 M, 5.6 × 10-7 M and 3.0 × 10-7 M, respectively (S/N = 3). The practical application of the present modified electrode was demonstrated by the determination of DA, AA and UA in calf serum and fetal calf serum samples.
文摘The aim of this study was to prepare diphenhydramine hydrochloride (DPH)-loaded orally fast-disintegrating mini-tablets (OFDMTs) containing either L-aspartic acid (Asp) or L-glutamic acid (Glu) as bitterness-suppressant, to characterize the prepared tablets and to evaluate their bitterness under conditions mimicking those of the oral cavity. The preparation of five formulation batches of the OFDMTs involved mixing DPH, with or without two different concentrations of Asp or Glu, and a premix containing a disintegrating agent. When all ingredients were well mixed, the mixture was directly compacted to form small (4 mm diameter) DPH-loaded OFDMTs. There were only small differences between the tablets with respect to mass, diameter, width and hardness. The disintegration times of the five formulation batches of DPH-loaded OFDMTs were measured using the OD-mate, a disintegration test apparatus in which conditions resemble those of the oral cavity. The disintegration times were all within 10 s of exposure to a medium representing the inside of the oral cavity. Rapid release profiles were observed for DPH, Asp and Glu in these dissolution tests. The taste sensor outputs of samples taken at different times (5 - 30 s) from the dissolution test solutions of the four DPH-loaded OFDMTs containing Asp or Glu were significantly inhibited compared with those of control DPH-loaded OFDMT. These results suggest that the inclusion of Asp or Glu in DPH-loaded OFDMTs is sufficient to mask bitterness in the oral cavity for the first 30 s after the tablet is placed in the mouth. It is anticipated that swallowing will have taken place within 30 s.
基金Supported by National Natural Science Foundation of China(No.81873249)National Natural Science Foundation of Shandong Province(No.ZR2022MH319)Young Taishan Scholars Program of Shandong Province(No.tsqn201909200)。
文摘Objective:To investigate the anti-liver cancer effects and aspartic acid(Asp)-related action mechanism of Euphorbia fischeriana Steud.(LD).Methods:The mice model of liver cancer was established by injection of H22 cells.After 5 days,mice were randomly divided into model group,sorafenib group(20 mg/kg),LD high-dose(LDH,1.36 g/kg) group,LD medium-dose(LDM,0.68 g/kg) group,and LD low-dose(LDL,0.34 g/kg)group,10 mice each group.Drugs were intragastrically administered to the mice once daily for 10 days,respectively.Body weight,tumor size and tumor weight were recorded.Hepatic index was calculated.Pathological changes of liver cancer tissues were evaluated by hematoxylin and eosin staining and TUNEL staining.Liquid chromatography-mass spectrometer was used to analyze different metabolites between the model and LDH groups.Results:After LD treatment,tumor weight,tumor size and hepatic index were reduced compared with the model group.Necrocytosis and karyorrhexis of tumor cells were found.Moreover,61 differential metabolites(18 up-regulated,43 down-regulated) were affirmed and 20 pathways of KEGG(P<0.05) were gotten.In addition,Bel-7402,HepG2 and H22 cell viabilities were significantly increased after adding Asp into the medium.And then,the cell proliferation effect induced by Asp was ameliorated by LD.Conclusion:The anti-liver cancer efficacy of LD extract was validated in H22 mice model,and inhibition of Asp level might be the underlying mechanism.
基金funded by National Natural Science Foundation of China(Nos.22076023 and 21677032)the Fundamental Research Funds for the Central Universities(China)(Nos.2242022k30030 and 2242022k30031).
文摘Light emitting diode(LED-UV)/chlorine disinfection can replace UV/chlorine disinfection in wastewater treatment plants and water supply plants.Halonitromethanes(HNMs)are a class of novel nitrogenous disinfection by-products,which are characterized by higher cytotoxicity and genotoxicity than regulated disinfection by-products.Herein,the impact factors and pathways of HNMs formation from aspartic acid(ASP)were investigated during LED-UV_(265)/chlorine disinfection.The results showed that three types of chlorinated-HNMs(Cl-HNMs)were found during LED-UV265/chlorine disinfection,and their concentrations increased first and then declined as the reaction progressed.Cl-HNMs yields increased with increasing LED-UV_(265)intensity,free chlorine dosage,and ASP concentration,which declined with increasing pH(6.0–8.0).Meantime,the important impact of the coexisting ions contained in water matrices on HNMs formation from ASP was observed during LED-UV_(265)/chlorine disinfection.It was found that copper ions(Cu^(2+))promoted Cl-HNMs formation.Furthermore,when bromide(Br–)appeared during LED-UV265/chlorine disinfection,nine types of HNMs were detected simultaneously.Moreover,Br–not only converted Cl-HNMs toward brominated(chlorinated)-HNMs and brominated-HNMs but also showed a marked effect on HNMs concentrations and species.Subsequently,the possible pathways of HNMs formation from ASP were proposed during LED-UV_(265)/chlorine disinfection.At last,it was proved that the formation trends of HNMs obtained in the real waters were similar to those in simulated waters.This work elaborated on the influence factors and pathways of HNMs formation,which is conducive to controlling the HNMs produced during LED-UV_(265)/chlorine disinfection.
基金supported by grants to Yuanchao Wang from the China National Funds for Innovative Research Groups(31721004)the key program of the National Natural Science Foundation of China(31430073)+2 种基金the Chinese Modern Agricultural Industry Technology System(CARS-004-PS14)the National Key R&D Program of China(SQ2018YFD020042)Research in the W.X.laboratory is supported by the Chinese Thousand Talents Plan and the Chinese Academy of Sciences.B.G.is supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX18.0662).
文摘Plants secrete defense molecules into the extracellular space (the apoplast) to combat attacking microbes. However, the mechanisms by which successful pathogens subvert plant apoplastic immunity remain poorly understood. In this study, we show that PsAvh240, a membrane-localized effector of the soybean pathogen Phytophthora sojae, promotes P. sojae infection in soybean hairy roots. We found that PsAvh240 interacts with the soybean-resistant aspartic protease GmAP1 in planta and suppresses the secretion of GmAP1 into the apoplast. By solving its crystal structure we revealed that PsAvh240 contain six a helices and two WY motifs. The first two a helices of PsAvh240 are responsible for its plasma membrane-localization and are required for PsAvh240's interaction with GmAP1. The second WY motifs of two PsAvh240 molecules form a handshake arrangement resulting in a handshake-like dimer. This dimerization is required for the effector's repression of GmAP1 secretion. Taken together, these data reveal that PsAvh240 localizes at the plasma membrane to interfere with GmAP1 secretion, which represents an effective mechanism by which effector proteins suppress plant apoplastic immunity.
基金Supported by CAMS Innovation Fund for Medical Sciences,No.2023-I2M-C&T-B-043National High Level Hospital Clinical Research Funding,No.2022-PUMCH-B-015+1 种基金CAMS Innovation Fund for Medical Sciences,No.2021-1-12M-002Beijing Municipal Natural Science Foundation,No.M22014.
文摘BACKGROUND There is a lack of clinical evidence on the efficacy and safety of transitioning from a thrice-daily pre-mixed insulin or basal-prandial regimen to insulin degludec/aspart(IDegAsp)therapy,with insufficient data from the Chinese population.AIM To demonstrate the efficacy,safety,and treatment satisfaction associated with the transition to IDegAsp in type 2 diabetes mellitus(T2DM).METHODS In this 12-week open-label,non-randomized,single-center,pilot study,patients with T2DM receiving thrice-daily insulin or intensive insulin treatment were transitioned to twice-daily injections of insulin IDegAsp.Insulin doses,hemoglobin A1c(HbA1c)levels,fasting blood glucose(FBG),hypoglycemic events,a Diabetes Treatment Satisfaction Questionnaire,and other parameters were assessed at baseline and 12-weeks.RESULTS This study included 21 participants.A marked enhancement was observed in the FBG level(P=0.02),daily total insulin dose(P=0.03),and overall diabetes treatment satisfaction(P<0.01)in the participants who switched to IDegAsp.There was a decrease in HbA1c levels(7.6±1.1 vs 7.4±0.9,P=0.31)and the frequency of hypoglycemic events of those who switched to IDegAsp decreased,however,there was no statistically significant difference.CONCLUSION The present findings suggest that treatment with IDegAsp enhances clinical outcomes,particularly FBG levels,daily cumulative insulin dose,and overall satisfaction with diabetes treatment.
基金the National Natural Science Foundation of China(51106051,51206044)the National Science Foundation of China(71273090,71573084)+1 种基金the Fundamental Research Funds for the Central Universities(2016YQ07,2015QN09,2014MS36,2014ZD14)the Beijing Natural Science Foundation(3132017)and“111”Project(B12034).
文摘In order to better understand the mechanism of NO_(x)and N_(2)Oprecursors(NH_(3)and HCN)from aspartic acid(Asp)pyrolysis,decomposition reaction networks resulting in the generation of NH_(3)and HCN were investigated by employing density function theory methods.After several pathways were analyzed in detail,two series of pyrolytic reactions containing three possible pathways were proposed.All the reactants,transition states,intermediates and products were optimized,also the electronic properties on these crucial points were discussed,which shows that Cαacts as the most active site to initiate the pyrolysis reaction,where the direct Cα-Cβbond breakage,due to the atomic charge population of repulsion,led to one key route for the generation of HCN,and the transfer of Hαfrom Cαto Cβresulting in another key route for the generation of HCN,while the transfer of Hαfrom Cαto N atom of Asp resulting in the key route for the generation of HN3.Further,the kinetic analysis based on speed control method in each key reaction pathway was conducted to further compare the generation of HCN and NH_(3)under various temperatures.The above results are in accordance with the related experimental results.
文摘BACKGROUND This case report describes a protocol developed by Danaun Medical Clinic for the introduction of a pioneering intervention comprising intravenous human placen-tal extract(HPE)therapy to improve the liver function of patients with chronic liver disease(CLD).CASE SUMMARY This study involved data from patients whose chief complaint was reduced quality of life attributable to CLD.The new treatment approach resulted in improvements in the liver function and fatty liver of 30 patients with CLD.Im-provements were observed using abdominal ultrasonography.Unlike traditional methods,this protocol provided more sustainable and meaningful results.Treat-ment with 10 mL of HPE administered intravenously once or twice per week significantly improved liver function.The observed improvements in fatty liver and liver function suggest the utility of this approach for the management of patients with CLD.CONCLUSION This case series highlights the potential of innovative treatments for patients with CLD that could improve the quality of life of the patients.
