动物气味的顶空取样技术及其在水貂肛腺成分分析中的应用

我们设计了一种用于动物气味的顶空 (headspace)取样装置 ,并结合溶剂解吸附和气质联用技术 ,通过对水貂 (Mustelavision)肛腺分泌物的挥发性成分的分析验证这种装置的可行性。出现 5个气谱峰 ,对应的质谱显示其分子量和分子式依次为峰 1:10 2 (C5H10 S)、峰 2 :10 4(C5H12 S)、峰 3:10 2 (C5H10 S)、峰 4:136(C5H12 S2 )和峰 5 :134 (C5H10 S2 )。峰 1、峰 3和峰 5分别为以前研究所鉴定出的 3种主要成分 :2 ,2 二甲基硫代环丁烷、2 乙基硫代环丁烷和 3,3 二甲基 1,2 二硫代环戊烷 ,2 ,2 二甲基硫代环丁烷为优势成分 ,组成无性别间差异。这些结果与以前研究一致 ,说明了这种顶空取样装置的可靠性。峰 2和峰 4两种成分以前在水貂肛腺中未曾发现 ,初步分析可能分别为 3 甲基 1 丙基硫醇和 1,5 戊二硫醇。尽管这两个成分有待进一步分析确定 ,但可以肯定分子量为 10 4和 136的成分不仅在水貂肛腺分泌物中没有发现过 ,而且在已经研究过的鼬属动物和食肉类的肛腺中都未发现过 ,能检测出更多的成分 ,说明这种方法的可靠性很高。     

短梗霉黑色素的分离纯化及结构的初步分析

采用热碱提取、水煮酸沉法从短梗霉发酵液中提取得到黑色素粗品,再经DMSO萃取、酸性甲醇(pH=2)沉淀得到不含多糖和蛋白的短梗霉黑色素。此黑色素不溶于水及常规有机溶剂,可溶于碱性溶液和DMSO;离子交换色谱分析表明黑色素组分均一,出峰时间26±0.5 m in;紫外光谱谱图最大吸收峰为215 nm左右,未见蛋白(280 nm)与核酸(260 nm)的特征吸收峰;红外光谱谱图具有黑色素3μm和6μm的特征吸收峰,并含大量的羟基、氨基,与核磁共振和液质联机谱图结合分析推出短梗霉黑色素可能含有酚羟基、羧基和吲哚等官能团,主要结构骨架为5,6-二羟基吲哚-羧酸和多巴醌,推断该黑色素为酪氨酸酶控制合成的真黑素。     

Fonsecaea monophora黑素的理化性质及其合成途径的分析研究

目的探讨Fonsecaea monophora黑素的理化性质及其合成途径。方法通过化学分析、紫外光谱、红外光谱和电子顺磁共振波谱等明确F.monophora黑素的理化性质;通过比对F.monophora菌株在基础培养基(马铃薯葡萄糖琼脂(PDA)培养基、L-DOPA PDA培养基)和含黑素抑制剂培养基(DOPA黑素抑制剂培养基、DHN黑素抑制剂培养基)的菌落生长情况,采用BioTek酶标仪EON定量分析其黑素合成,以明确F.monophora的黑素合成途径。结果 F.monophora黑素与合成L-DOPA黑素的理化性质相似;菌株在含L-DOPA培养基较PDA培养基产生更多的黑素,且在含DOPA黑素抑制剂叠氮化钠及DHN黑素抑制剂苯肽、三环唑培养基中其黑素合成均明显降低。结论 F.monophora黑素主要为LDOPA黑素,可能共同存在DOPA黑素和DHN黑素合成途径。     

HPLC-PAD法优化乌骨鸡活性肽分离纯化

乌骨鸡是一种具有药用价值的鸡种,乌骨鸡的鸡肉蛋白通过酶促水解后可获得多肽产物乌骨鸡活性肽,营养价值高,分离纯化活性肽是研究乌骨鸡应用价值的基础。利用装置C18反相色谱柱或TSKgel凝胶色谱柱的高效液相色谱仪进行乌骨鸡活性肽的分离优化,针对流动相、流速进行优化的同时,参考波长、进样量,以出峰数为主,结合分离度等考察分离效果。结果表明:C18柱的出峰数随甲醇含量及流速的降低而增加;三氟乙酸或磷酸盐作缓冲液时出峰数基本一致,但分离度不同;综合因素得pH 6.0磷酸盐/6%甲醇/水体系的流动相、0.2 mL/min的流速为该实验下的最佳分离条件。TSKgel柱的乙腈分离效果优于甲醇,梯度洗脱效果较好;综合因素得出0.1%三氟乙酸/(10%～25%)乙腈/水体系的流动相、0.5 mL/min的流速为该实验下的最佳分离条件。     

海口城市水体底泥中重金属含量分布、形态特征及环境质量评价

分析了海口市19 个水体59 个底泥样品中重金属的含量和形态, 并进行环境质量评价。结果表明: 海口城市周边水体底泥的Cr、Ni、Cu、Cd 元素含量高于市区底泥; 而Hg、Pb、Zn 元素含量分布则表现出市区高于周边的规律。As 未表现出空间差异。海口底泥中Cu、Pb、Zn 以残渣态为主(占40%左右); Cr、Ni、Hg、As 四种元素以残渣态为主(占60%以上); Cd 元素形态则以离子交换态为主(占30%以上), 除残渣态之外的其余形态所占比例和高于80%。环境质量评价结果表明, 海口城市底泥中As、Cd、Cu 三种元素的含量较低, 基本上符合海洋沉积物质量(GB18668-2002)一、二级标准。而Cr、Ni 和Hg、Zn、Pb 五种元素含量稍高, 周边底泥中Cr、Ni 两元素含量符合或超过三级标准, 市区底泥中Hg、Zn、Pb 元素含量分别符合二、三或超三级标准。     

饲喂泰和乌骨鸡及其黑素对小鼠肝、肠、肾酶组织化学活性的影响

应用酶组织化学方法观察了老年小鼠经饲喂泰和乌骨鸡及其黑素一个半月后,肝、肠、肾SDH、Mg^2 －ATPase、G－6－Pase、5′－Nase和MAO的酶活性变化。结果显示;肝、肠、肾SDH、Mg^2 -ATPase、G－6－Pase、5′-Nase的酶活性增强。MAO的酶活性减弱。结果提示：泰和乌骨鸡及其黑素具有促进机体代谢、维持内环境稳定,延缓衰老的作用。     

人体头发黑色素的电子能谱研究

本文用电子能谱研究了人体黑发色素的某些基本性质。研究结果表明头发黑素中含两种不同化学状态的硫原子,且它们为黑素分子本身所固有;长辫发末端和中段的黑素含量相同,但末端黑素中高价硫相对含量较多;头发黑素在热的稀碱液中有一定的溶解性,溶解时含硫基团不发生化学键断裂,黑素的碱性溶液用酸中和时在pH为3～4左右出现棕色沉淀,沉淀物和溶解前的黑素的S2p电子能谱基本相同;头发黑素中的硫原子易被过氧化氢和高锰酸盐氧化,但不被抗坏血酸和盐酸羟胺还原。鉴于上述结果,作者认为头发黑素可能是由不含硫的氨基酸和含硫氨基酸通过复杂的氧化作用和共聚作用生成的无规则聚合物。     

人体头发黑色素的电子能谱研究

本文用电子能谱研究了人体黑发色素的某些基本性质。研究结果表明头发黑素中含两种不同化学状态的硫原子,且它们为黑素分子本身所固有;长辫发末端和中段的黑素含量相同,但末端黑素中高价硫相对含量较多;头发黑素在热的稀碱液中有一定的溶解性,溶解时含硫基团不发生化学键断裂,黑素的碱性溶液用酸中和时在pH为3～4左右出现棕色沉淀,沉淀物和溶解前的黑素的S2p电子能谱基本相同;头发黑素中的硫原子易被过氧化氢和高锰酸盐氧化,但不被抗坏血酸和盐酸羟胺还原。鉴于上述结果,作者认为头发黑素可能是由不含硫的氨基酸和含硫氨基酸通过复杂的氧化作用和共聚作用生成的无规则聚合物。     

苦玄参甙A和B的结构(简报)

<正> 从苦玄参(Picria fel-terrae Lour.)抗癌有效的B部分,分离出二种新四环三萜甙,称苦玄参甙A和B(Picfelterraenin A和B)。经元素分析确定其分子式为C_(41)H_(62)O_(13)和C_(42)H_(64)O_(14)。二者的IR均有羟基(3420cm~(-1))、羰基(1685cm~(-1))、与羰基共轭的双键(1585cm~(-1))及强的C—O伸缩振动吸收峰(1160—950cm~(-1))。二者     

土壤无机元素化学形态与滇重楼主要有效成分相关性研究

探究野生和栽培产地滇重楼根际土壤中16种无机元素的5种化学形态分布规律及其与药材品质的相关性，为滇重楼科学化种植及药效功能的开发利用提供参考依据。采用BCR顺序提取法提取不同化学形态的无机元素，采用电感耦合等离子体质谱法(ICP-MS)进行元素含量测定，再利用SPSS软件进行相关性分析。滇重楼的野生品和栽培品的根际土壤中16种无机元素主要以残渣态为主，且野生品和栽培品在各元素含量方面差异明显，栽培品高于野生品；Ca、Mg元素在水溶态和交换态中的含量明显高于其他元素，P、Mo元素含量则较低；Ca、Mg、Fe、Al元素在有机态和铁锰氧化态中的含量明显较高，但Na元素未检测出；相关性分析表明，滇重楼中重楼皂苷的积累与根际土壤中的P、K元素呈显著的负相关关系，与Fe、Al、Se、Ba等元素呈显著正相关关系。综上，滇重楼根际土壤中的无机元素大部分以残渣态形式存在，P、K元素的存在在一定程度上抑制了重楼皂苷的积累，Fe、Al、Se、Ba等元素促进了重楼皂苷的积累。     

The interaction of the trp repressor from Escherichia coli with L-tryptophan and indole propanoic acid

The binding of the corepressor, L-tryptophan, and an inducer, indole propanoic acid, to the trp repressor from Escherichia coli was studied by absorbance, fluorescence, circular dichroic and proton NMR spectroscopy. The two ligands bind to the same site on the repressor in the same orientation; they are molecular competitors. The binding site is of relatively low polarity and contains at least one methyl group that lies 0.3 nm over the indole moiety near the C5 proton of the bound ligand, and an aromatic residue, probably tyrosine. The dissociation constant was determined as a function of temperature and pH. At 25 degrees C in 0.1 M phosphate buffer, pH 7.6, the dissociation constant is 18 +/- 2 microM for both ligands. In the same buffer system, the van't Hoff enthalpy for dissociation is 35.5 +/- 1 kJ/mol for tryptophan, and 30.5 +/- 2 kJ/mol for indole propanoic acid. The affinity of the repressor for indole propanoic acid is independent of pH in the range 7 less than 10, but decreases four fold for tryptophan in the same range. The amino group of tryptophan makes a significant contribution to its binding affinity. Difference NMR spectra showed that there are few changes of protein resonances on binding ligands. The NMR signals of the bound resonances were assigned by difference and nuclear Overhauser effect spectroscopy. The properties of the bound resonances are consistent with the ligands being largely immobilised within the binding site. The difference spectra, and the known functional differences of the two ligands, suggest that tryptophan induces a slightly different conformational state in the repressor from that induced by indole propanoic acid. There is no evidence for a global transition. The rate of dissociation of ligands is relatively large, being in the range 400-600 s-1.     

红外-核磁共振光谱-免疫亲和柱法解析梨孢镰孢菌代谢产物成分

利用红外光谱,核磁共振光谱结合免疫亲和柱的方法解析梨孢镰孢菌代谢产物成分,为真菌代谢产物的分析提供新的信息.将F.Poae菌株在GYM培养基上25℃条件下培养12 h后转至8℃培养12h,交替进行4周,将其代谢产物分离纯化、结晶,80℃干燥后用红外光谱议分析产物结构,然后利用免疫亲和柱特异性,比较产物经T-2免疫亲和柱纯化前后的1H核磁谱图.由红外谱图可判断目标组分存在与单端孢霉烯族毒素相同的特征官能团,初步判定产物为单端孢霉烯族毒素.通过1H核磁谱图比较T-2免疫亲和柱纯化前后物质结构一致.梨孢镰孢菌代谢产物成分为T-2毒素.红外-核磁共振光谱结合免疫亲和柱的方法解析梨孢镰孢菌代谢产物的方法在国内外尚未见报道.     

Structure and properties of phospholipid-peptide monolayers containing monomeric SP-B(1-25) II. Peptide conformation by infrared spectroscopy

The conformation and orientation of synthetic monomeric human sequence SP-B(1-25) (mSP-B(1-25)) was studied in films with phospholipids at the air-water (A/W) interface by polarization modulation infrared reflectance absorption spectroscopy (PM-IRRAS). Modified two-dimensional infrared (2D IR) correlation analysis was applied to PM-IRRAS spectra to define changes in the secondary structure and rates of reorientation of mSP-B(1-25) in the monolayer during compression. PM-IRRAS spectra and 2D IR correlation analysis showed that, in pure films, mSP-B(1-25) had a major alpha-helical conformation plus regions of beta-sheet structure. These alpha-helical regions reoriented later during film compression than beta structural regions, and became oriented normal to the A/W interface as surface pressure increased. In mixed films with 4:1 mol:mol acyl chain perdeuterated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt) (DPPC-d(62):DOPG), the IR spectra of mSP-B(1-25) showed that a significant, concentration-dependent conformational change occurred when mSP-B(1-25) was incorporated into a DPPC-d(62):DOPG monolayer. At an mSP-B(1-25) concentration of 10 wt.%, the peptide assumed a predominantly beta-sheet conformation with no contribution from alpha-helical structures. At lower, more physiological peptide concentrations, 2D IR correlation analysis showed that the propensity of mSP-B(1-25) to form alpha-helical structures was increased. In phospholipid films containing 5 wt.% mSP-B(1-25), a substantial alpha-helical peptide structural component was observed, but regions of alpha and beta structure reoriented together rather than independently during compression. In films containing 1 wt.% mSP-B(1-25), peptide conformation was predominantly alpha-helical and the helical regions reoriented later during compression than the remaining beta structural components. The increased alpha-helical structure of mSP-B(1-25) demonstrated here by PM-IRRAS and 2D IR correlation analysis in monolayers of 4:1 DPPC:DOPG containing 1 wt.% (and, to a lesser extent, 5 wt.%) peptide may be relevant for the formation of the intermediate order 'dendritic' surface phase observed in similar surface films by epi-fluorescence.     

Distinguishing cell types or populations based on the computational analysis of their infrared spectra

Infrared (IR) spectroscopy of intact cells results in a fingerprint of their biochemistry in the form of an IR spectrum; this has given rise to the new field of biospectroscopy. This protocol describes sample preparation (a tissue section or cytology specimen), the application of IR spectroscopy tools, and computational analysis. Experimental considerations include optimization of specimen preparation, objective acquisition of a sufficient number of spectra, linking of the derived spectra with tissue architecture or cell type, and computational analysis. The preparation of multiple specimens (up to 50) takes 8 h; the interrogation of a tissue section can take up to 6 h (～100 spectra); and cytology analysis (n = 50, 10 spectra per specimen) takes 14 h. IR spectroscopy generates complex data sets and analyses are best when initially based on a multivariate approach (principal component analysis with or without linear discriminant analysis). This results in the identification of class clustering as well as class-specific chemical entities.     

Peculiarities of secondary structure of serum albumin of some representatives of the animal kingdom

Methods of infrared (IR) spectroscopy and circular dichroism (CD) are suitable techniques for detection of proteins structural changes. These methods were used for determinating peculiarities of the secondary structure of serum albumins in some representatives of two classes of reptiles: Horsfield's tortoise (Testudo horsfieldi), water snake (Natrix tessellata) and grass snake (Natrix natrix) and birds: domestic goose (Anser anser), domestic chicken (Gallus domesticus), domestic duck (Anas platyrhyncha) and dove colored (Columba livia). An analysis of IR spectra and spectra obtained by the method of CD of serum albumins of both classes representatives revealed that beta-folding structure and alpha-helical sections that form the alpha-conformation play an important role in conformational structure formation of polypeptide chain and also disordered sites of molecules of these proteins. It was observed that certain redistribution depending on animals species exists, in the formation of secondary structure of serum albumins of the investigated representatives of reptiles and birds classes between the content of beta-folding structure, alpha-helical sections and disordered sites in molecules of these proteins.     

Metabolomic analysis of methyl jasmonate treated Brassica rapa leaves by 2-dimensional NMR spectroscopy

The metabolomic analysis of Brassica rapa leaves treated with methyl jasmonate was performed using 2-dimensional J-resolved NMR spectroscopy combined with multivariate data analysis. The principal component analysis of the J-resolved NMR spectra showed discrimination between control and methyl jasmonate treated plants by principal components 1 and 2. While the level of glucose, sucrose and amino acids showed a decrease after methyl jasmonate treatment, hydroxycinnamates and glucosinolate were highly increased. Methyl jasmonate treatment resulted in a long-term accumulation of indole glucosinolate and indole-3-acetic acid, lasting up to 14 days after treatment. Malate conjugated hydroxycinnamates also exhibited an increase until 14 days after methyl jasmonate treatment, these compounds might play an important role in plant defence responses mediated by methyl jasmonate.     

Differentiation of live, dead and treated cells of Escherichia coli O157:H7 using FT-IR spectroscopy

Aims: To apply specific collection techniques and spectroscopy to differentiate between live and dead Escherichia coli O157:H7 cells, as well as cells subjected to various inactivation treatments, including heat, salt, UV, antibiotics and alcohol. Methods and Results: Fourier transform‐infrared (FT‐IR) spectroscopy was used to analyse E. coli O157:H7 cells, after filtration or immunomagnetic collection. Partial least squares analysis of the spectra quantified live E. coli O157:H7 in the presence of dead cells with an R² > 0·996. Canonical variate analysis (CVA) not only differentiated between spectra of 100% dead and 100% live cells but also between 1% live : 99% dead and 100% dead. CVA using principal components also differentiated between the spectra of the differentially treated cells at a 95% confidence level, and Cooman plots showed clear separation between clusters of spectra of bacteria exposed to the different inactivation treatments. Mahalanobis distances (MD) corroborated the results of CVA. Conclusions: These results demonstrated the effectiveness of rapid cell collection and FT‐IR spectroscopy techniques to differentiate between live and dead E. coli O157:H7 cells. Significance and Impact of the Study: This technique has potential applications for use with foods subjected to various inactivation treatments.