耐高温产乙醇酿酒酵母菌S-13的特性研究

以耐高温产乙醇酿酒酵母菌S-13为出发菌株,在优化的培养条件下,通过连续传代转接实验对其性能进行研究。结果表明,菌株S-13种子液的最佳培养时间为12～14 h,最佳发酵时间为48 h;其遗传稳定性在20代之内相对较好,每相邻2代的乙醇浓度相对误差小于5％;对乙醇的耐受能力为14％(体积分数);热致死温度为66～67℃...     

Kinetic Study and Mathematical Modelling of the Growth of S. cerevisiae 522D in Presence of K2 Killer Protein

This paper deals with the study of the kinetics of batch fermentations for a sensitive strain of S. cerevisiae growing in a culture medium containing K2 killer protein. The inhibition due to the killer toxin was measured by the reduction of the viable biomass, ethanol production and glucose consumption compared with a reference fermentation. The reference culture was run under the same conditions, but using a heat-denatured solution of killer protein. Results showed a decrease of the viable population of 67·8% after 15 h incubation. The fermentation time for the total consumption of the glucose was significantly affected by the presence of the killer toxin. The specific rate of ethanol production was also affected during the fermentation. However, the yields of ethanol and biomass were very similar for both fermentations. A kinetic mathematical model was proposed to explain the dynamics of the S. cerevisiae 522D growth in the presence of the K2 killer protein. The results of the suggested simulation were in agreement with the experimental data. © 1997 SCI.     

HPLC-ESI-MS^2法测定制药废水中青霉素G残留

建立了一种测定制药废水中青霉素G残留的高效液相色谱-电喷雾质谱方法。样品经Octadecyl C18固相萃取柱净化后,以乙腈-水-乙酸（体积比20∶80∶0.005）体系溶液作为流动相,电喷雾质谱检测器进行定性和定量分析。该方法检出限为5μg/L,相对标准偏差（RSD%）为6.2%,回收率是64.9%～76.3%。实验结果表明,该方法具有准确、快速的特点,适合制药废水中青霉素G残留的测定。     

Identification of Plasmalogen Cardiolipins from Pectinatus by Liquid Chromatography–High Resolution Electrospray Ionization Tandem Mass Spectrometry

High resolution electrospray ionization tandem mass spectrometry (HR-ESI–MS/MS) was used to analyze cardiolipins (Ptd₂Gro) including their plasmalogen forms from three species of the anaerobic beer-spoilage bacterial genus Pectinatus. Cardiolipins including their plasmalogens were analyzed by HR-ESI–MS/MS on Orbitrap and almost 100 cardiolipins (i.e. tetra-acyl—Ptd₂Gro, plasmenyl-tri-acyl—PlsPtd₂Gro, and di-plasmenyl-di-acyl—Pls₂Ptd₂Gro) of three classes were identified. The structures of the molecular species that consist of various regioisomers and structurally similar compounds were revealed in detail. The high resolution mass spectrometry allowed the unambiguous structural assignment of Ptd₂Gro, PlsPtd₂Gro, and Pls₂Ptd₂Gro in the three species of Pectinatus, which contain predominantly odd numbered fatty acids.     

Lipidomic Study of Precursors of Endocannabinoids in Freshwater Bryozoan Pectinatella magnifica

Freshwater bryozoan Pectinatella magnifica was collected from a sand pit (South Bohemia). The total lipids after extraction from lyophilized bryozoans were analyzed using high‐performance liquid chromatography/high‐resolution negative tandem electrospray mass spectrometry. A total of 19 lipid classes were identified, including N‐acyl‐substituted phospholipids, that is, N‐acylphosphatidylethanolamine and N‐acylphosphatidylserine in their plasmenyl forms. Based on gas chromatography/mass spectrometry of 3‐pyridylcarbonyl (picolinyl) esters, a very unusual fatty acid was identified, namely 24:7n‐3 (all‐cis‐3,6,9,12,15,18,21‐tetracosaheptaenoic acid). The presence of polyunsaturated fatty acids in individual classes is very specific: arachidonic and eicosapentaenoic acids being predominantly bound as amides in N‐acyl phospholipids, that is, diacyl‐N‐acylphosphatidylethanolamines (NAPtdEtn), plasmenyl‐N‐acylphosphatidyl ethanolamines (PlsNAPtdEtn), diacyl‐N‐acylphosphatidylserines (NAPtdSer), and plasmenyl‐N‐acylphosphatidylserines (PlsNAPtdSer). While 24:6n‐3 was identified in the sn‐2 position of several phospholipids, 24:7n‐3 was identified in only two plasmalogens, that is, PlsNAPtdEtn and PlsNAPtdSer. Thanks to the tandem mass spectrometry, we managed to identify the position of all acyl groups in both diacyl‐ and also in alkenyl‐acyl‐(plasmenyl) molecular species of N‐acylphospholipids. The identification of the molecular species of N‐acyl‐substituted phosphatidylethanolamine and phosphatidylserine, including their plasmalogen forms, in the freshwater bryozoan P. magnifica has enabled the identification of endogenous cannabinoid precursors.     

Profiling and Imaging of Phospholipids in Brains of Abcd1‐Deficient Mice

ABCD1 is a gene responsible for X‐linked adrenoleukodystrophy (X‐ALD), and is critical for the transport of very long‐chain fatty acids (VLCFA) into peroxisomes and subsequent β‐oxidation. VLCFA‐containing lipids accumulate in X‐ALD patients, although the effect of ABCD1‐deficiency on each lipid species in the central nervous system has not been fully characterized. In this study, each phospholipid and lysophospholipid species in Abcd1‐deficient mice brains were profiled by liquid chromatography‐mass spectrometry. Among the phospholipid and lysophospholipid species that are significantly more enriched in Abcd1‐deficient mice brains, VLCFA were present in 75, 15, 5, 4, and 1 species of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, lysophosphatidylcholine, and lysophosphatidylethanolamine, respectively. Most VLCFA were incorporated at the sn‐1 position of phosphatidylcholine and phosphatidylethanolamine. Among the phospholipid species that are significantly less enriched in Abcd1‐deficient mice brains, odd‐numbered saturated or mono‐unsaturated fatty acyl moieties are contained in all phosphatidylcholine species. In addition, a number of phosphatidylglycerol, phosphatidylinositol, and phosphatidylserine species contained highly unsaturated fatty acyl moieties. Intriguingly, 44:1 phosphatidylcholine with VLCFA was mainly distributed in the gray matter, such as the cortex, but not in the white matter in the cerebrum and cerebellum. These results show that ABCD1‐deficiency causes metabolic alternation of long‐chain fatty acids and VLCFA. Moreover, our results imply a molecular mechanism for the incorporation of saturated or monounsaturated VLCFA into the sn‐1 position of phospholipids, and also indicate that the distribution of phospholipids with VLCFA may correlate with the development of X‐ALD.     

Comprehensive and quantitative profiling of lipid species in human milk,cow milk and a phospholipid‐enriched milk formula by GC and MS/MSALL

Here we present a workflow for in‐depth analysis of milk lipids that combines gas chromatography (GC) for fatty acid (FA) profiling and a shotgun lipidomics routine termed MS/MS^ALL for structural characterization of molecular lipid species. To evaluate the performance of the workflow we performed a comparative lipid analysis of human milk, cow milk, and Lacprodan^® PL‐20, a phospholipid‐enriched milk protein concentrate for infant formula. The GC analysis showed that human milk and Lacprodan have a similar FA profile with higher levels of unsaturated FAs as compared to cow milk. In‐depth lipidomic analysis by MS/MS^ALL revealed that each type of milk sample comprised distinct composition of molecular lipid species. Lipid class composition showed that the human and cow milk contain a higher proportion of triacylglycerols (TAGs) as compared to Lacprodan. Notably, the MS/MS^ALL analysis demonstrated that the similar FA profile of human milk and Lacprodan determined by GC analysis is attributed to the composition of individual TAG species in human milk and glycerophospholipid species in Lacprodan. Moreover, the analysis of TAG molecules in Lacprodan and cow milk showed a high proportion of short‐chain FAs that could not be monitored by GC analysis. The results presented here show that complementary GC and MS/MS^ALL analysis is a powerful approach for characterization of molecular lipid species in milk and milk products. Practical applications : Milk lipid analysis is routinely performed using gas chromatography. This method reports the total fatty acid composition of all milk lipids, but provides no structural or quantitative information about individual lipid molecules in milk or milk products. Here we present a workflow that integrates gas chromatography for fatty acid profiling and a shotgun lipidomics routine termed MS/MS^ALL for structural analysis and quantification of molecular lipid species. We demonstrate the efficacy of this complementary workflow by a comparative analysis of molecular lipid species in human milk, cow milk, and a milk‐based supplement used for infant formula. A workflow for milk lipid analysis based on combined gas chromatography and high‐resolution shotgun lipidomics. In‐depth structural characterization and quantification of molecular lipid species in milk and milk products.     

酵母工程菌细胞高密度发酵的研究进展

构建重组酵母工程菌表达抗原或细胞因子等,是研发新生物制品的趋势之一,实现酵母工程菌的高密度发酵是维持制品生产规模和降低成本的重要技术途径。本文就影响酵母工程菌高密度发酵的因素,包括菌株的生物学特性和发酵工艺特点、培养基种类及配方、发酵罐结构及性能、发酵过程各项重要工艺参数或变量的控制等及在生物制品和生物制药行业中酵母工程菌细胞高密度发酵的进展作一综述。     

福建省水产动物苗种中氯霉素残留现状研究

对2008-2011年4年中对福建省内各种苗孵化基地随机抽检的17个经济苗种共计204个批次的样品,采用高效液相色谱-串联质谱联用法检测氯霉素含量。结果显示:大黄鱼,对虾中检出率较高。     

Properties of Emulsions Formed In Situ In a Heavy‐Oil Reservoir during Water Flooding: Effects of Salinity and pH

Differing from conventional emulsions, water‐in‐oil (W/O) emulsions are produced with no additional surfactants in this study. The testing results show that both interfacial tension (IFT) and dilational modulus at all salinities and pH are much higher than those of normal emulsions. A high IFT is not good for making emulsions, but a higher dilational modulus will contribute to more stable emulsions. Emulsion stability declines slightly as salinity increases and the most unstable W/O emulsion appears at pH = 7. To deeply understand the effects of salinity and pH on emulsion stability, petroleum acid is extracted and characterized using Fourier transform ion cyclotron resonance mass spectrometry.     

Distribution of the major fatty acids of human milk betweensn-2 andsn-1,3 positions of triacylglycerols

Human milk triacylgycerols (TAG) were analyzed by tandem mass spectrometry. The SIMPLEX method and a simple linear model were used to interpret the distribution of fatty acids between thesn-2 andsn-1,3 positions in 24 major molecular weight groups of TAG. The number of regio-isomeric pairs of TAG varied between 3 and 18 in each of these groups. Hexadecanoic (16∶0), tetradecanoic (14∶0) and dodecanoic acids (12∶0) typically occupied thesn-2 position in TAG containing less than 54 acyl carbons, whereas long-chain C18 and C20 acids were predominantly located at the primary positions. The positions of the three fatty acids within a TAG molecule were shown to depend on the fatty acid combination. The maximum of 12∶0 in thesn-2 position appeared at acyl carbon number (ACN) 48, the maxima of 14∶0 were at ACN 44 and ACN 50, and for 16∶0 at ACN 46 and 52.     

Comprehensive Quantitation Using Two Stable Isotopically Labeled Species and Direct Detection of <Emphasis Type="Italic">N</Emphasis>-Acyl Moiety of Sphingomyelin

Sphingomyelin (ceramide‐phosphocholine, CerPCho) is a common sphingolipid in mammalian cells and is composed of phosphorylcholine and ceramide as polar and hydrophobic components, respectively. In this study, a qualitative liquid chromatography‐electrospray ionization tandem mass spectrometry (LC–ESI–MS/MS/MS) analysis is proposed in which CerPCho structures were assigned based on product ion spectra corresponding to sphingosylphosphorylcholine and N‐acyl moieties. From MS/MS/MS analysis of CerPCho, we observed product ion spectra of the N‐acyl fatty acids as [RCO₂]^? ions as well as sphingosylphosphorylcholine. A calibration curve for CerPCho was constructed using two stable isotopically labeled CerPCho species and then used to quantify the CerPCho species in HeLa cells as a proof‐of‐principle study. The present study proposes an accurate method for quantifying and assigning structures to each CerPCho species in crude biologic samples by LC–ESI–MS/MS/MS analysis.     

Factors affecting silver biosorption by an industrial strain of Saccharomyces cerevisiae

Factors affecting silver biosorption by Saccharomyces cerevisiae biomass, obtained as a waste product from industry, were examined. Maximum removal of silver from solution was achieved within 5 min. Increasing the concentration of biomass in experimental flasks from 1 to 8 mg cm⁻³ decreased both silver accumulation, from 224·7 to 89·5 μmol Ag g⁻¹ dry wt, and associated H⁺ ion release, from 109·4 to 31·7 μmol H⁺ g⁻¹ dry wt. The presence of 1·0 mol dm⁻³ cadmium or methionine decreased silver biosorption by 40% and 93% respectively. Boiling in 100 mmol dm⁻³ NaOH or 10 mmol dm⁻³ sodium dodecyl sulphate decreased silver biosorption by 54% and 25% respectively. A temperature increase from 4°C to 55°C decreased silver biosorption by 9%. The metabolic state of the yeast had no effect on silver biosorption. Decreasing the pH of the silver solution caused a reduction in metal removal by the biomass.     

中药制剂中地西泮的LC/MS/MS分析方法研究

采用液相色谱串联质谱联用仪分析中药制剂中的地西泮.用乙腈-0.01mol/L乙酸铵水溶液(6 4)超声提取试样中的地西泮,离心分离,取上清液过滤膜后用LC/MS/MS进行检测.通过对提取方式和液相色谱分离条件的优化,建立了中药制剂中地西泮的LC/MS/MS检测方法.样品加标的回收率为87.6%～96.8%,相对标准偏差为3.1%～9.6%,多反应监测(选择离子对286.0/194.2及286.0/223.1)检出限为0.5ug/L.     

超高效液相色谱/串联质谱法测定化妆品中15种色素

采用超高效液相色谱-串联电喷雾四极杆质谱在多反应监测模式下测定了特殊功效类化妆品中的15种色素。样品按照不同状态分别进行前处理,目标物以乙酸铵和甲醇为流动相,经C18色谱柱分离。在超高效液相色谱/串联质谱分析过程中以保留时间和离子对（母离子和两个碎片离子）信息比较定性,以母离子和响应值高的碎片离子进行定量。该方法检出限为0.025～1.0μg/g,目标物的添加回收范围为51.3%～107%,相对标准偏差为0.9%～9.8%。     

高效液相色谱串联质谱测定武夷岩茶中草甘膦残留量的方法探讨

采用高效液相色谱串联质谱建立了武夷岩茶样品中草甘膦的残留量的测定方法。样品经水固相萃取和茶叶专用萃取柱(TPT)净化后,在硼酸盐缓冲液中与9-芴甲基氯甲酸酯(FMOC-Cl)进行衍生化反应,以1%乙酸铵溶液和乙腈为流动相,质谱检测采用电喷雾正离子化模式和多反应监测模式。结果表明,草甘膦在1~10 ng/mL范围内线性良好,线性相关系数r=0.998。通过对空白武夷岩茶样品进行4个加标水平的添加回收实验(n=5),草甘膦的平均回收率和相对标准偏差(RSD)分别为87.3%~98.0%和3.46~5.12。     

GC／MS／MS分析物体表面上黏附的痕量克百威

应用串联质谱法（GC／MS／MS）对物体表面上黏附克百威及其水解产物呋喃酚进行检验研究。选择质荷比为164的离子作为母离子,击发电压为0．7V时,克百威及其水解产物呋喃酚二次电离碎片适中,质谱图清晰,方法的检测限为0．03gg／mL。所拟方法能有效提高克百威的检测灵敏度。     

The identification of an adenovirus receptor by using affinity capture and mass spectrometry

A tandem mass spectrometry--based approach is demonstrated for detecting a receptor for Ad37, one of the causative agents for epidemic keratoconjunctivitis. Partial purification of membrane glycoproteins was performed by using lectin-affinity chromatography and SDS-PAGE. Gel bands that were shown to bind Ad37 by using Viral Overlay Protein Blot Assay (VOPBA) were excised, proteolyzed and analyzed by using nanoLC-MS/MS to identify putative receptors contained in a mixture of proteins. Four candidate receptors were identified among approximately 50 proteins based on a search against a protein database. Inhibition of gene delivery mediated by an Ad37 vector, with antibodies against the glycoproteins identified by tandem mass spectrometry, strongly indicated that Membrane Cofactor Protein (MCP), a member of the complement regulatory family of proteins, is the receptor. This rapid and sensitive MS/MS-based strategy is perceived to have wide potential applications for the detection of viral receptors.     

Molecular Species of Phospholipids with Very Long Chain Fatty Acids in Skin Fibroblasts of Zellweger Syndrome

The ratio of C_26:0/C_22:0 fatty acids in patient lipids is widely accepted as a critical clinical criterion of peroxisomal diseases, such as Zellweger syndrome and X-linked adrenoleukodystrophy (X-ALD). However, phospholipid molecular species with very long chain fatty acids (VLCFA) have not been precisely characterized. In the present study, the structures of such molecules in fibroblasts of Zellweger syndrome and X-ALD were examined using LC–ESI–MS/MS analysis. In fibroblasts from Zellweger patients, a large number of VLCFA-containing molecular species were detected in several phospholipid classes as well as neutral lipids, including triacylglycerol and cholesteryl esters. Among these lipids, phosphatidylcholine showed the most diversity in the structures of VLCFA-containing molecular species. Some VLCFA possessed longer carbon chains and/or larger number of double bonds than C_26:0-fatty acid (FA). Similar VLCFA were also found in other phospholipid classes, such as phosphatidylethanolamine and phosphatidylserine. In addition, VLCFA-containing phospholipid species showed some differences among fibroblasts from Zellweger patients. It appears that phospholipids with VLCFA, with or without double bonds, as well as C_26:0-FA might affect cellular functions, thus leading to the pathogenesis of peroxisomal diseases, such as Zellweger syndrome and X-ALD.