Compound-specific stable isotope analysis of individual amino acids(CSIA-AA)has been widely used in ecological and biogeochemical studies.It has been proven to be powerful in tracing the diet sources and trophic inter...Compound-specific stable isotope analysis of individual amino acids(CSIA-AA)has been widely used in ecological and biogeochemical studies.It has been proven to be powerful in tracing the diet sources and trophic interactions.However,assessing the N sources of mesopelagic fishes has been inconclusive because the mesopelagic fishes’unique domain(water depth ranged from 0 to 1000 m)and unresolved nitrogen isotopes of various forms.This study proposes a new method for coupling instruments(ion chromatography and PreconIRMS)and chemical method of oxidation-reduction of amino acids,and also combinedδ15N of AAs withδ13C of fatty acids(FAs)to analyze the trophic interactions of mesopelagic fishes in the South China Sea(SCS).AAs were isolated by ion chromatography with high peak resolution and collected by an automated fraction collector.The chemical method then converted the AAs into N2 O with a robust oxidation yields and suitable molar ratio of NH2 OH to.Finally,theδ15N of AAs at 20 nmol were measured with a reasonable precision(<0.6‰).With this method,this study report the first batch high precisionδ15N of AAs andδ13C of FAs of mesopelagic fishes collected from SCS.Diaphus luetkeni,Chauliodus minimus and Bathygadus antrodes showed similarδ13C values of 20:4 n-6(~-28‰),while Argyropelecus affinis and Stomias had similar values(~-32‰).These results reflect that mesopelagic fishes had complex diet sources.An increase of 4‰inδ15N of glutamic acid(Glu)was found between piscivorous and planktivorous fishes,which might suggest a trophic discrimination factor of mesopelagic fishes in the SCS.This study usedδ13C of 20:4 n-6 to reveal the diet sources of mesopelagic fishes andδ15N of Glu to clarify trophic level between piscivorous and planktivorous fishes.Thus,this combinative method could therefore ultimately be applied in a variety of deep-sea ecosystem.展开更多
Amino acids are the building blocks of proteins,which are the most abundant macromolecules in living cells.From the standpoint of the photon interaction cross sections of amino acids,the mass attenuation coefficients,...Amino acids are the building blocks of proteins,which are the most abundant macromolecules in living cells.From the standpoint of the photon interaction cross sections of amino acids,the mass attenuation coefficients,half and tenth value layers,mean free path,effective atomic and electronic cross sections,effective atomic number,and effective electron density of fifteen essential amino acids have been determined for 133Ba,137Cs,and 60Co gamma-ray sources.The MCNP-4C code and the XCOM program have been used to calculate these parameters.The results have been compared to the available experimental and theoretical data.The theoretical results agreed with the experimental data,with RD values of ≤±7%.In the energy region of 81-1332.5 keV,it was found that the μm,σa,and revalues of the amino acids decreased as the photon energy increased,and the increasing density of amino acids had no steady effect on these quantities.Additionally,results demonstrated that the HVL,TVL,and MFP values increased with the increase in photon energy.The μm,σa,and Zeff values of aspartic acid were the highest among those of all amino acids,and they were the lowest for isoleucine.The Zeff value of each sample containing H,C,N,and O atoms was nearly constant in the studied energy region.The Neffvalues of the studied amino acids varied in the range of 3.14×10^23-3.44×10^23 electron/g.Furthermore,the Neffvalues were approximately independent of the amino acid type in this energy region.展开更多
Suzuki-Miyaura coupling reaction of N-protected 4-iodopheyl alanine isoxazoles with arylboronic acids,catalyzed by palladium,efficiently produce benzyl-N-（4-bipheyl）-2-（3-methyl-5（E）-2-aryl-1-ethenyl-4-isoxazolyl...Suzuki-Miyaura coupling reaction of N-protected 4-iodopheyl alanine isoxazoles with arylboronic acids,catalyzed by palladium,efficiently produce benzyl-N-（4-bipheyl）-2-（3-methyl-5（E）-2-aryl-1-ethenyl-4-isoxazolyl）-amino-2-oxoethyl）carba- mates in good yields.This process is first of its kind to construct carbon-carbon bond formation having biaryl motif on amino acid linked isoxazole moiety.展开更多
Objective:To investigate the actions of cytokine profile in the immune cells by a seven amino acid peptide mimic from HVR1 of HCV (GQTYTSG,named 7P).Methods:The peripheral blood mononuclear cells (PBMCs) from 17 healt...Objective:To investigate the actions of cytokine profile in the immune cells by a seven amino acid peptide mimic from HVR1 of HCV (GQTYTSG,named 7P).Methods:The peripheral blood mononuclear cells (PBMCs) from 17 healthy blood donors were stimulated with 7P,and the cytokine levels in CD4+CD8-,CD4-CD8+ T cells,NK,NKT cells were analyzed by the intracellular cytokine staining.Results:The frequency of cells which secreted interferon-γ (IFN-γ) was found to be significantly increased in all cells,interleukin-10(IL-10) was significantly increased in CD4+CD8-,CD4-CD8+ T cells but decreased in NK,NKT cells,and tumor necrosis factor-α (TNF-α) was decreased in CD4+CD8-,CD4-CD8+ but increased in NK cells.Conclusion:7P could induce a cytokine profile in different immune cells in vitro and there was some difference between the CD4+CD8-,CD4-CD8+ T cells which represented the adaptive immunity cells and NK,NKT cells which represented the innate immunity cells.This kind of variation of cytokine profile might contribute to anti-virus and anti-inflammatory immune reaction.展开更多
Objective: To ascertain the role of HIV-1 gp120 env PNGs variations and sequence length polymorphism following transmission events as possible supporting forensic evidence to determine directionality of HIV transmissi...Objective: To ascertain the role of HIV-1 gp120 env PNGs variations and sequence length polymorphism following transmission events as possible supporting forensic evidence to determine directionality of HIV transmission. Method: An observational study of HIV-1 infected family members, where median and range values of the amino acid lengths and PNGs for the genotyped C2V5 region were calculated. Wilcoxon rank-sum test was used to determine differences in these parameters between different family members. Results: For heterosexual transmission, two mothers had longer C3 sequences relative to that of their spouses;p=0.006 and=0.025 whilst the opposite was observed for one mother, p = 0.028. No clear trends were observed for PNGs. Index children had longer C2V5 amino acid sequences compared to their mothers p = 0.013, 0.040, 0.043 for families 205, 375, 567 respectively. Second siblings “V4 and V5 sequences were generally shorter relative to the maternal ones p = 0.039 and 0.028, respectively. Adults had longer V3 amino acid sequences compared to children;p = 0.018. Similar trends were also observed regarding PNGs within the entire C2V5 region, C3 and V4 sub-regions;p= 0.0025, 0.005 and 0.008, respectively. First siblings’ C2V5 and C3 sequence lengths were significantly longer relative to those of the second siblings;p = 0.005 and 0.007, respectively. Conclusion: Our results are suggestive that HIV-1 env C2V5 amino acid length polymorphism and PNGs tend to increase with age and HIV disease progression. Though sensitive and should be cautiously handled, it is tempting to propose the direc-tionality of the HIV transmission events with respect to C3 sequence length polymorphisms. Correlating HIV-1 env C2V5 amino acid length polymorphism and age of infection may be the first step towards a possible valuable piece of forensic evidence which may be useful in criminalisation of willful HIV infections. However, bigger studies are war-ranted to substantiate the authenticity of this potentially useful application.展开更多
The purpose of this paper was to identify content changes in the main nutritional indicators of three common leafy vegetables, and to provide a theoretical basis for the protection of leafy vegetables from acid rain. ...The purpose of this paper was to identify content changes in the main nutritional indicators of three common leafy vegetables, and to provide a theoretical basis for the protection of leafy vegetables from acid rain. The experiment investigated the effects of simulated acid rain on four main nutritional indicators, including soluble sugar, total free amino acid, soluble protein and vitamin C during the application of simulated acid rain(SAR) in pakchoi(Brassica rapa chinensis), rape(Brassica campestris L.) and lettuce(Lactuca sativa Linn. var. ramosa Hort). The vegetables were respectively exposed to SAR of pH=7.0, 5.6, 5.0, 4.0, 3.0 and a control level of pH=6.5. The concentrations of the four main nutritional indicators were determined at harvest. The results show that nutritional quality of the three leafy vegetable species decreased with the declining of pH values of SAR. The higher the acidity of SAR was, the more significant the inhibitions were. Nutritional quality of lettuce was the most affected by simulated acid rain, followed by pakchoi and rape. The change range of soluble protein content was higher than those of the other three indicators’ contents, which indicates that soluble protein is most sensitive to simulated acid rain.展开更多
碳氮稳定同位素在地球科学、生命科学、环境科学、农业科学等各个领域有着广泛的应用。由于同时含有碳氮原子的氨基酸是蛋白质的构成单位,参与机体的代谢,具有重要的生物功能,因此在利用同位素示踪研究中,氨基酸有其重要的研究价值。本...碳氮稳定同位素在地球科学、生命科学、环境科学、农业科学等各个领域有着广泛的应用。由于同时含有碳氮原子的氨基酸是蛋白质的构成单位,参与机体的代谢,具有重要的生物功能,因此在利用同位素示踪研究中,氨基酸有其重要的研究价值。本文仅就利用气相色谱-燃烧-同位素比值质谱仪(gas chromatography-combustion-isotope ratio mass spectrometry,GC-C-IRMS)分析氨基酸的碳氮同位素比值的衍生化方法进行总结,比较各种方法的优缺点,以期对于分析氨基酸的碳氮同位素比值的研究工作提供有益的帮助。展开更多
基金The National Basic Research Program(973 Program)of China under contract No.2014CB441502the National Natural Science Foundation of China under contract No.41876074the Cross-research Center Project by QNLM under contract No.JCZX202007。
文摘Compound-specific stable isotope analysis of individual amino acids(CSIA-AA)has been widely used in ecological and biogeochemical studies.It has been proven to be powerful in tracing the diet sources and trophic interactions.However,assessing the N sources of mesopelagic fishes has been inconclusive because the mesopelagic fishes’unique domain(water depth ranged from 0 to 1000 m)and unresolved nitrogen isotopes of various forms.This study proposes a new method for coupling instruments(ion chromatography and PreconIRMS)and chemical method of oxidation-reduction of amino acids,and also combinedδ15N of AAs withδ13C of fatty acids(FAs)to analyze the trophic interactions of mesopelagic fishes in the South China Sea(SCS).AAs were isolated by ion chromatography with high peak resolution and collected by an automated fraction collector.The chemical method then converted the AAs into N2 O with a robust oxidation yields and suitable molar ratio of NH2 OH to.Finally,theδ15N of AAs at 20 nmol were measured with a reasonable precision(<0.6‰).With this method,this study report the first batch high precisionδ15N of AAs andδ13C of FAs of mesopelagic fishes collected from SCS.Diaphus luetkeni,Chauliodus minimus and Bathygadus antrodes showed similarδ13C values of 20:4 n-6(~-28‰),while Argyropelecus affinis and Stomias had similar values(~-32‰).These results reflect that mesopelagic fishes had complex diet sources.An increase of 4‰inδ15N of glutamic acid(Glu)was found between piscivorous and planktivorous fishes,which might suggest a trophic discrimination factor of mesopelagic fishes in the SCS.This study usedδ13C of 20:4 n-6 to reveal the diet sources of mesopelagic fishes andδ15N of Glu to clarify trophic level between piscivorous and planktivorous fishes.Thus,this combinative method could therefore ultimately be applied in a variety of deep-sea ecosystem.
文摘Amino acids are the building blocks of proteins,which are the most abundant macromolecules in living cells.From the standpoint of the photon interaction cross sections of amino acids,the mass attenuation coefficients,half and tenth value layers,mean free path,effective atomic and electronic cross sections,effective atomic number,and effective electron density of fifteen essential amino acids have been determined for 133Ba,137Cs,and 60Co gamma-ray sources.The MCNP-4C code and the XCOM program have been used to calculate these parameters.The results have been compared to the available experimental and theoretical data.The theoretical results agreed with the experimental data,with RD values of ≤±7%.In the energy region of 81-1332.5 keV,it was found that the μm,σa,and revalues of the amino acids decreased as the photon energy increased,and the increasing density of amino acids had no steady effect on these quantities.Additionally,results demonstrated that the HVL,TVL,and MFP values increased with the increase in photon energy.The μm,σa,and Zeff values of aspartic acid were the highest among those of all amino acids,and they were the lowest for isoleucine.The Zeff value of each sample containing H,C,N,and O atoms was nearly constant in the studied energy region.The Neffvalues of the studied amino acids varied in the range of 3.14×10^23-3.44×10^23 electron/g.Furthermore,the Neffvalues were approximately independent of the amino acid type in this energy region.
文摘Suzuki-Miyaura coupling reaction of N-protected 4-iodopheyl alanine isoxazoles with arylboronic acids,catalyzed by palladium,efficiently produce benzyl-N-（4-bipheyl）-2-（3-methyl-5（E）-2-aryl-1-ethenyl-4-isoxazolyl）-amino-2-oxoethyl）carba- mates in good yields.This process is first of its kind to construct carbon-carbon bond formation having biaryl motif on amino acid linked isoxazole moiety.
基金Supported by the National High Technology Research and Development Program of China(863 Program,No. 2006AA022494)
文摘Objective:To investigate the actions of cytokine profile in the immune cells by a seven amino acid peptide mimic from HVR1 of HCV (GQTYTSG,named 7P).Methods:The peripheral blood mononuclear cells (PBMCs) from 17 healthy blood donors were stimulated with 7P,and the cytokine levels in CD4+CD8-,CD4-CD8+ T cells,NK,NKT cells were analyzed by the intracellular cytokine staining.Results:The frequency of cells which secreted interferon-γ (IFN-γ) was found to be significantly increased in all cells,interleukin-10(IL-10) was significantly increased in CD4+CD8-,CD4-CD8+ T cells but decreased in NK,NKT cells,and tumor necrosis factor-α (TNF-α) was decreased in CD4+CD8-,CD4-CD8+ but increased in NK cells.Conclusion:7P could induce a cytokine profile in different immune cells in vitro and there was some difference between the CD4+CD8-,CD4-CD8+ T cells which represented the adaptive immunity cells and NK,NKT cells which represented the innate immunity cells.This kind of variation of cytokine profile might contribute to anti-virus and anti-inflammatory immune reaction.
文摘Objective: To ascertain the role of HIV-1 gp120 env PNGs variations and sequence length polymorphism following transmission events as possible supporting forensic evidence to determine directionality of HIV transmission. Method: An observational study of HIV-1 infected family members, where median and range values of the amino acid lengths and PNGs for the genotyped C2V5 region were calculated. Wilcoxon rank-sum test was used to determine differences in these parameters between different family members. Results: For heterosexual transmission, two mothers had longer C3 sequences relative to that of their spouses;p=0.006 and=0.025 whilst the opposite was observed for one mother, p = 0.028. No clear trends were observed for PNGs. Index children had longer C2V5 amino acid sequences compared to their mothers p = 0.013, 0.040, 0.043 for families 205, 375, 567 respectively. Second siblings “V4 and V5 sequences were generally shorter relative to the maternal ones p = 0.039 and 0.028, respectively. Adults had longer V3 amino acid sequences compared to children;p = 0.018. Similar trends were also observed regarding PNGs within the entire C2V5 region, C3 and V4 sub-regions;p= 0.0025, 0.005 and 0.008, respectively. First siblings’ C2V5 and C3 sequence lengths were significantly longer relative to those of the second siblings;p = 0.005 and 0.007, respectively. Conclusion: Our results are suggestive that HIV-1 env C2V5 amino acid length polymorphism and PNGs tend to increase with age and HIV disease progression. Though sensitive and should be cautiously handled, it is tempting to propose the direc-tionality of the HIV transmission events with respect to C3 sequence length polymorphisms. Correlating HIV-1 env C2V5 amino acid length polymorphism and age of infection may be the first step towards a possible valuable piece of forensic evidence which may be useful in criminalisation of willful HIV infections. However, bigger studies are war-ranted to substantiate the authenticity of this potentially useful application.
基金Supported by the National Basic Research Program of China(No.2005CB422207)
文摘The purpose of this paper was to identify content changes in the main nutritional indicators of three common leafy vegetables, and to provide a theoretical basis for the protection of leafy vegetables from acid rain. The experiment investigated the effects of simulated acid rain on four main nutritional indicators, including soluble sugar, total free amino acid, soluble protein and vitamin C during the application of simulated acid rain(SAR) in pakchoi(Brassica rapa chinensis), rape(Brassica campestris L.) and lettuce(Lactuca sativa Linn. var. ramosa Hort). The vegetables were respectively exposed to SAR of pH=7.0, 5.6, 5.0, 4.0, 3.0 and a control level of pH=6.5. The concentrations of the four main nutritional indicators were determined at harvest. The results show that nutritional quality of the three leafy vegetable species decreased with the declining of pH values of SAR. The higher the acidity of SAR was, the more significant the inhibitions were. Nutritional quality of lettuce was the most affected by simulated acid rain, followed by pakchoi and rape. The change range of soluble protein content was higher than those of the other three indicators’ contents, which indicates that soluble protein is most sensitive to simulated acid rain.
文摘碳氮稳定同位素在地球科学、生命科学、环境科学、农业科学等各个领域有着广泛的应用。由于同时含有碳氮原子的氨基酸是蛋白质的构成单位,参与机体的代谢,具有重要的生物功能,因此在利用同位素示踪研究中,氨基酸有其重要的研究价值。本文仅就利用气相色谱-燃烧-同位素比值质谱仪(gas chromatography-combustion-isotope ratio mass spectrometry,GC-C-IRMS)分析氨基酸的碳氮同位素比值的衍生化方法进行总结,比较各种方法的优缺点,以期对于分析氨基酸的碳氮同位素比值的研究工作提供有益的帮助。
