高效液相色谱-紫外检测法同时测定洗面奶中4种N-月桂酰氨基酸表面活性剂

N-月桂酰氨基酸(NLAAs)表面活性剂与传统表面活性剂相比在安全性上具有明显的优势,应用领域日益增多。但由于NLAAs的紫外吸收较弱,采用高效液相色谱-紫外检测进行含量测定存在一定困难,一般使用示差折光指数检测器、蒸发光散射检测器等通用型检测器来进行检测。为解决这一难题,本研究通过优化流动相的组成,选择合适的色谱柱和检测波长,建立了高效液相色谱-紫外检测同时测定月桂酰谷氨酸(LG)、月桂酰甘氨酸(LC)、月桂酰丙氨酸(LA)、月桂酰肌氨酸(LS)4种NLAAs表面活性剂的方法。样品在乙腈-0.10%H_(3)PO_(4)水溶液(60∶40,v/v)中超声提取10 min,滤膜过滤后用高效液相色谱仪测定,以乙腈-0.10%H_(3)PO_(4)水溶液为流动相进行梯度洗脱,经Agilent Eclipse Plus C_(18)色谱柱(150 mm×4.6 mm,5μm)分离,在205 nm波长处进行检测。结果显示:4种NLAAs在2.0~800.0 mg/L范围内呈良好的线性关系,相关系数(r)均≥0.9995,检出限(LOD)为0.17~0.49 mg/L,定量限(LOQ)为0.57~1.63 mg/L。在0.60、4.50、15.00、24.00 mg/g 4个加标水平下,NLAAs的加标回收率在94.3%~107.4%范围内。采用该方法对5个洗面奶样品中的NLAAs进行含量测定,发现所有样品都含有一种或多种NLAAs化合物,NLAAs的总含量在64.58~97.01 mg/g范围内。该方法前处理简单,测试快速,方法精密度、准确性、稳定性良好,适于洗面奶中NLAAs的含量测定,也可为该类型表面活性剂原料纯度、合成产率检测及产品的质量控制提供有效的技术参考。

Effects of Amino Acids Replacing Nitrate on Growth,Nitrate Accumulation,and Macroelement Concentrations in Pak-choi (Brassica chinensis L.)

一个水耕法的实验被执行决定在小白菜(Brassica chinensis L.) 在氮(N) ，磷(P) ，和钾(K) 的生长，硝酸盐累积，和集中上用 20 单个氨基酸在营养液代替 20% nitrate-N 的影响射击。20% nitrate-N 什么时候与完整的硝酸盐处理，新鲜的小白菜射击和干燥重量相比被精氨酸( Arg )代替，但是20% nitrate-N 什么时候被丙氨酸(翼)代替，显著地增加了( P ≤ 0.05 )，缬氨酸(瓦尔)，白氨酸(列伊)，异白氨酸( Ile )，脯氨酸(专业版)，本氨基丙酸( Phe )，蛋氨酸(相遇)，天门冬酸(毒蛇)， glutamic ( Glu )，离氨酸( Lys )，甘氨酸( Gly )，丝氨酸(重量的单位)，苏氨酸( Thr )，半胱氨酸( Cys )，和酷氨酸( Tyr )，新鲜的射击和干燥重量显著地减少了( P ≤ 0.05 )。在用天门冬素(Asn ) 和夫酸安(Gln ) 代替 20% nitrate-N 以后，新鲜的射击和干燥重量是未受影响的。比作完整的硝酸盐处理，氨基酸代替处理除了 Cys， Gly，组氨酸(他的) ，并且 Arg，显著地减少了(P ≤ 0.05 ) 在植物射击的硝酸盐集中。显著地除了 Cys，列伊，专业版，和在另外的氨基酸处理的植物组织的遇见的、全部的 N 集中增加了(P ≤ 0.05 ) 。氨基酸也影响了全部的 P 和 K 集中，但是效果不同取决于单个氨基酸。改进小白菜射击质量， Gln 和 Asn 由于他们小白菜生长上的不足道的效果，他们在硝酸盐集中的重要减小，和他们宏元素的增加在植物满足，可以被用来部分代替 nitrate-N。

Diagnosis in bile acid-CoA:Amino acid N-acyltransferase deficiency

Cholate-CoA ligase(CCL) and bile acid-CoA:amino acid N-acyltransferase(BAAT) sequentially mediate bile-acid amidation.Defects can cause intrahepatic cholestasis.Distinction has required gene sequencing.We assessed potential clinical utility of immunostaining of liver for CCL and BAAT.Using commercially available antibodies against BAAT and CCL,we immunostained liver from an infant with jaundice,deficiency of amidated bile acids,and transcription-terminating mutation in BAAT.CCL was normally expressed.BAAT expression was not detected.Immunostaining may facilitate diagnosis in bileacid amidation defects.

Synthesis of novel fullereneα-amino acid conjugates

Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affording two monofuUerene α-amino acids, monofullerene aspartic acid （mFas） and monofullerene glutamic acid （mFgu）. Then a bifullerene glutamic acid conjugate （bFguC） was synthesized by reaction of mFgu containing protected amino group with N-substituted 3,4-fullero pyrrolidine.

Improved method for measuring the δ15N compound-specific amino acids: Application on mesopelagic fishes in the South China Sea

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.

Pyrolysis-GC/MS of Menthyl Esters of N-Benzoxycarbonyl Amino Acid

With the aid of a Pyrolysis-GC/TOF MS technique, the pyrolysis behaviour of two menthyl esters of N-benzoxycarbonyl amino acid was investigated. A clear pattern emerges involving the cleavage of the bond linking the menthyl ring to the carboxy group, followed by further degradation of the fragments. The major pyroproducts were p-menth-l-ene pyrolysed at a higher temperature or p-menth-2-ene pyrolysed at a lower temperature, and various derivatives of cyclohexene pyrolyzed from the menthyl ring. In addition, some of the products were also iden- tified as derivatives of benzene from the pyrolysis of benzyloxyl moiety.

Validation of the Lysine Requirement as Reference Amino Acid for Ideal In-Feed Amino Acid Ratios in Modern Fast Growing Meat-Type Chickens

Nitrogen (N) balance studies were conducted with male growing broiler chickens to reevaluate the lysine (Lys) requirement of a modern broiler strain (Ross 308), making use of eight diets with graded crude protein (CP) supply (6% - 34% CP as-fed). Wheat, soy protein concentrate, wheat gluten, fishmeal and crystalline amino acids (AAs) were the protein sources in the experimental diets with Lys as limiting AA. Following an adaptation period of five days, two consecutive excreta collection periods (2 × 5 d) were conducted: 10 - 20 d of age (starter period) and 25 - 35 d of age (grower period). Statistical evaluation of N balance data utilized an exponential modelling approach. Based on different dietary Lys efficiency, Lys requirement data were derived by modelling depending on average body weight (BW) during starter and grower period and targeted body protein deposition (PD), respectively. In addition, the influence of graded feed intake was taken into account. For the starter period at 600 g BW and assumed 10 g daily body PD, Lys requirement data between 741 mg and 823 mg per day were observed. The corresponding Lys in-feed concentration was 1.06% and 1.18%, dependent on supposed Lys efficiency at 70 g daily feed intake. For the grower period (average BW 1800 g), 1272 mg to 1473 mg Lys per day was needed to yield 16.5 g daily PD. The corresponding required Lys in-feed concentration was between 0.85% and 0.94% Lys for 150 g daily feed intake.

Synthesis and Structure Analysis of a Tripeptide Containing N-methyl Group Amino Acid

A convenient method of synthesizing a tripeptide-containing N-methyl group amino acid was developed using O-benzotriazole-N,N,N＇,N＇-tetramethyluronium-hexafluorophosphate as the condensing agent. The crystals of tripeptide had white needles belonging to the orthorhombic space group P2_12_12_1. The conformational preference for homochiral tripeptides with one N-methylated amide bond was also investigated. Crystal-structure analysis showed that homochiral tripeptides with an internal N-methylated amide bond preferred a trans-amide form, thereby giving the peptide β-fold characteristics. Intermolecular C-H···O and N-H···O hydrogen bonds linked the molecules into a one-dimensional chain and stabilized the structure.

Syntheses and Crystal Structures of Two Diethyltin Complexes of N-Salicylidene-α-amino Acid

Two novel diethyltin（IV） complexes of N-salicylidenevaline （H2L1） and N-Sali- cylidenetryptophan （H2L^2）, Et2SrtL^1 1 and Et2SnL^2 2, were synthesized and characterized by elemental analysis, IR, ^1H NMR and X-ray single-crystal diffraction analysis. Complex 1 belongs to the trigonal system, space group R-3 with a = b = 19.2730（5）, c = 23.6890（13）A^°, V= 7620.4（5） A^°^3, Z = 6, Dc= 1.553 g/cm^3,μ= 1.518 mm^-1, F（000） = 3600, R = 0.0238 and wR = 0.0636. Complex 2 is of monoelinie system, space group P21/c with a = 13.7550（8）, b = 11.5425（7）, c = 12.7876（7）A^°, β= 93.585（1）°, V = 2026.3（2） A^°^3, Z = 4, Dc= 1.548 g/cm^3,μ = 1.286 mm^-1, F（000） = 976, R = 0.0298 and wR = 0.0722. Complex 1 is a cyclic trimer with a macrocyclic 12-membered ring structure formed by the bidentate bridging coordination of carboxylate group to tin atoms. The tin atom is six-coordinated in a distorted octahedral geometry. In complex 2, the distorted trigonal bipyramidal Et2SnL2 units are linked into polymeric chains by the weak Sn…O interaction involving Sn and the earbonyl O of an adjacent ligand, and the chains are further connected by intermolecular N-H…O hydrogen bonds to form a two-dimensional supramolecular structure.

Syntheses and Structural Characterization of Dimethyltin Complexs of N-(3-Methoxysalicylidene)-α-amino Acid

Three new dimethyltin complexes of N-（3-methoxysalicylidene）-α-amino acid,（CH3）2Sn（3-CH3O-2-OC6H3CH=NCHRCOO）（R = H,1;CH3,2;（CH3）2CH,3）,have been synthe-sized by treating dimethyltin dichloride with the potassium salt of the ligand and characterized by elemental analysis,IR and 1H NMR spectra.The crystal structure of [（CH3）2Sn（3-CH3O-2-OC6H3CH=NCH2COO）（CH3OH）]2 H2O（1a）,formed from methanol solution of 1,has been deter-mined.The crystal belongs to the monoclinic system,space group C/2c with a = 20.636（3）,b = 7.8854（9）,c = 20.668（2） ,β= 113.265（2）°,V = 3089.7（6） 3,Z = 4,Dc = 1.707 g/cm3,= 1.675 mm-1,F（000） = 1592,R = 0.0301 and wR = 0.0841.In complex 1a,the tin atom is six-coordinate and possesses a distorted [SnC2NO3] octahedral geometry with the two methyl groups occupying the trans positions.The weak Sn O interactions and intermolecular hydrogen bonds connected the molecules into an infinite chain.

Interaction between N-phosphoryl-α-,β-and γ-amino acids and nucleosides

The reactions of four different N-（O,O＇-diisopropyl） phosphoamino acids （DIPP-aa）, such as N-phosphoryl-L-α-alanine （DIPP- L-α-Ala）, N-phosphoryl-D-α-alanine （DIPP-D-α-A1a）, N-phosphoryl-β-alanine （DIPP-β-A1a） and N-phosphoryl-γ-amino butyric acid （DIPP-γ-Aba）, and four nucleosides, adenosine （A）, guanosine （G）, cytidine （C） and uridine （U）, were studied by electrospray ionization tandem mass spectrometry （ESI-MS/MS） and HPLC/ESI-MS. DIPP-L-α-A1a and DIPP-D-α-A1a produced the same phosphorylated nucleosides, dinucleotides and phosphoroligopeptide. However, DIPP-β-A1a and DIPP-γ-Aba gave no relevant products.

Improving the Dietary Protein Quality by Amino Acid Fortification with a High Inclusion Level of Micro Algae (<i>Spirulina platensis</i>) or Insect Meal (<i>Hermetia illucens</i>) in Meat Type Chicken Diets

The objective of this study was to measure protein quality parameters (PPV, NPU and NPUstd) of chicken diets with complete substitution of soybean meal (SBM) by Spirulina meal (SM) or partly defatted Hermetia meal (HM). N balance experiments were based on the quantitative excreta collection method, divided into starter period (10 - 20 d) and grower period (25 - 35 d). The study utilized 70 all male meat type chicken (Ross 308). Data assessment applied the exponential N utilization model of the “Goettingen approach”. The control diet was based on wheat, corn and SBM. In four experimental diets SBM was completely substituted by SM or HM, but fortified with feed amino acids (AA) both on a basic level of supplementation (Lys and Met added equal to the control diet) and on an extended level (Lys, Met, Thr, Arg, Val, Ile, His added). At a basic level of AA supplementation, complete replacement of SBM by SM or HM in chicken diets depressed dietary protein quality significantly (p 0.05). However, the extended level of AA supplementation improved protein quality parameters of the diets with both of the alternative proteins significantly (p < 0.05), but still generally not on par with the control diet. The observed responses were accentuated when the well-known effect of N intake on protein utilization was eliminated through the standardization of N intake by application of the “Goettingen approach”.

The Synthesis of Some Novel N-[α-(Isoflavone-7-O-) Acetyl]Amino Acid Derivatives

A series of novel N-[α-(isoflavone-7-O-)acetyl] amino acid methyl esters were prepared from the efficient and regioselective alkylation of isoflavones with chloroacetyl amino acid derivatives under mild condition.

Interaction between N-Phospho-Amino Acids and Nucleoside in Aqueous Medium

Nucleosides were phosphorylated with different N- (O, O-diisopropyl) phosphoryl amino acids to give nucleoside mono phosphates in aqueous solution. 2', 3', and 5'-isomers had been confirmed by comparison with authentic samples on the basis of HPLC analysis. The conversion percentage of nucleoside indicated that N- (O, O-diisopropyl) phosphoryl aspartic acid reacted with adenosine and guanosine at a much higher rate than other kinds of N- phosphoryl amino acids. while phosphorylation of cytidine and uridine was relatively easy by using N- (O, O-diisopropyl) phosphoryl threonine. The result could give some clue to the prebiotic code origin of nucleic acid and protein.

AMPA与NMDA抗体重叠的自身免疫性脑炎合并眼阵挛-肌阵挛综合征1例报告

眼阵挛-肌阵挛综合征(OMS)是一种少见的神经系统综合征,与肿瘤相关,常见于儿童,成人少见,其特征是不自主、无节律、混乱、多向的眼球不自主运动,通常伴有四肢和躯干肌阵挛性抽搐、共济失调。抗α-氨基-3-羟基-5-甲基-4-异唑丙酸受体(AMPAR)与抗N-甲基-D-天冬氨酸受体(NMDAR)抗体重叠的自身免疫性脑炎合并眼阵挛-肌阵挛综合征的病例报道更为少见,对其临床表现及治疗缺乏全面的认识。现报道1例AMPAR与NMDAR抗体重叠的自身免疫性脑炎合并眼阵挛-肌阵挛综合征患者,并基于此病例对国内外相关文献进行复习,以期提高临床医生的认识。

Liquid Chromatography Detertmination of Amino Acids by Pre-Column Fluorescence Derivatization with Acridone-N-acetyl Chloride

A sensitive liquid chromatographic mcthod for the detection of andno acids with precolumn fluorescence derivatization with acridone-N-acetyl chloride has been developed. Andno acid derivatives were eluted in 4o ndn with good reproducibility. The reIative standard deviations (n=6) at an analytical concentration of 50 pmol are < 4%. The method described is also suitable for the analysis of andno acids in different biological samples.

Determination of Amino Acidsas Their N-Hydroxy-succinimidyl-3-indolylacetate Derivatives by Reversed-phase HPLC

The present paper covers the reversed phase HPLC separation and determination of fourteen derivatized amino acids with a new reagent N hydroxy succinimidyl 3 indolylacetate(SIIA). The derivatives of the amino acids were eluted by a mobile phase of methanol water containing 10 mmol/L H 3cit Na 2HPO 4 buffer of pH 3 5 and 1 2 mmol/L tetrabutylammonium bromide on an ODS column. The detection limits were pmol level or so, respectively, when a signal to noise ratio was 3. The method was applied to the determination of amino acids in tea sample with satisfactory results.

A Unique Heteronuclear Metal Organic Framework Based on Amino-acid and N-donor Ancillary Ligand: Synthesis, Structure and Characterization

A novel heteronuclear metal organic framework(MOF) incorporating both transition and alkali metal ions, namely, {(Ni_2K_2L_2·bipy]×6 H_2O]×2 H_2O}n(1, L = N-phosphonomethyl amino diacetic acid, bipy = 4,4?-dipyridine) has been obtained. Its structure was established by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy. The complex crystallizes in orthorhombic system, space group Pccn with a = 14.650(11), b = 36.56(3), c = 7.112(5) ? and V = 3809.3(8) ?~3. In this framework, bipy connects adjacent Ni–K heteronuclear coordination units into 1 D railway type chains, which are further propagated into 2 D deck-like array bearing large tunnels through the carboxylic oxygen from N-phosphonomethyl amino diacetic acid. The molar electrical conductivity of heteronuclear complex increases gradually with increasing the temperature. Complex 1 also exhibits strong photoluminescent emission in the visible region.