蛋鸡日粮含苏丹红Ⅳ的鸡蛋内源性代谢物差异性研究

采用高分辨Agilent 6530 液相色谱-四极杆/飞行时间质谱联用技术,对喂食日粮中含苏丹红Ⅳ(0、100、150、200 mg/kg)的海兰褐蛋鸡的鸡蛋进行代谢组学研究,即对喂养28 d后的鸡蛋样品分别在电喷雾离子源(electrospray ionization,ESI)正、负离子模式下进行检测,并通过相关代谢组学统计分析软件(mass profiler professional,MPP)对采集到的谱图进行主成分分析,从而获得蛋鸡食用苏丹红Ⅳ后鸡蛋中的代谢物信息。结果表明,该液质联用技术可将空白对照组与喂食苏丹红Ⅳ组进行明显的区分,并可借助数据库中23000种代谢物信息对发生显著变化(P<0.05, 倍数变化≥2)的差异性代谢物组分进行初步的鉴定。研究结果为深入进行苏丹红Ⅳ的代谢组学研究提供了依据。     

同位素内标-液质联用法测定鸡可食性组织中替米考星残留量

建立了鸡四种可食性组织中替米考星的液相色谱串联质谱内标法。样品经磷酸二氢钾缓冲液和乙腈提取后,C18固相萃取柱净化,以0.1%甲酸乙腈溶液和0.1%甲酸水为流动相,液相色谱串联质谱法测定,内标法定量。试验结果表明：鸡四种可食性组织中替米考星在1 μg/kg~100 μg/kg的浓度范围内呈线性关系,相关系数r大于0.99;替米考星在鸡四种可食性组织中的检测限为0.5 μg/kg,定量限为1 μg/kg;四种组织中替米考星添加浓度为1 μg/kg~4800 μg/kg时,批间平均回收率为94.6%~100.9%,批内、批间变异系数在1.11%-5.06%范围之间。本方法适用于鸡四种可食性组织中替米考星含量的测定。     

QuEChERS-液相色谱-串联质谱法测定鲤肝脏中氟虫腈及其代谢物残留

以QuEChERS作为样品前处理方法,结合高效液相色谱-串联质谱(HPLC-MS/MS)检测技术,建立了鲤(Cyprinus carpio)肝脏中氟虫腈(fipronil)及代谢物氟甲腈(fipronil desulfinyl)、氟虫腈亚砜(fipronil sulfide)和氟虫腈砜(fipronil sulfone...     

Quantitation Overcoming Matrix Effects of Lipophilic Toxins in Mytilus galloprovincialis by Liquid Chromatography-Full Scan High Resolution Mass Spectrometry Analysis (LC-HR-MS)

The analysis of marine lipophilic toxins in shellfish products still represents a challenging task due to the complexity and diversity of the sample matrix. Liquid chromatography coupled with mass spectrometry (LC-MS) is the technique of choice for accurate quantitative measurements in complex samples. By combining unambiguous identification with the high selectivity of tandem MS, it provides the required high sensitivity and specificity. However, LC-MS is prone to matrix effects (ME) that need to be evaluated during the development and validation of methods. Furthermore, the large sample-to-sample variability, even between samples of the same species and geographic origin, needs a procedure to evaluate and control ME continuously. Here, we analyzed the toxins okadaic acid (OA), dinophysistoxins (DTX-1 and DTX-2), pectenotoxin (PTX-2), yessotoxin (YTX) and azaspiracid-1 (AZA-1). Samples were mussels (Mytilus galloprovincialis), both fresh and processed, and a toxin-free mussel reference material. We developed an accurate mass-extracted ion chromatogram (AM-XIC) based quantitation method using an Orbitrap instrument, evaluated the ME for different types and extracts of mussel samples, characterized the main compounds co-eluting with the targeted molecules and quantified toxins in samples by following a standard addition method (SAM). An AM-XIC based quantitation of lipophilic toxins in mussel samples using high resolution and accuracy full scan profiles (LC-HR-MS) is a good alternative to multi reaction monitoring (MRM) for instruments with HR capabilities. ME depend on the starting sample matrix and the sample preparation. ME are particularly strong for OA and related toxins, showing values below 50% for fresh mussel samples. Results for other toxins (AZA-1, YTX and PTX-2) are between 75% and 110%. ME in unknown matrices can be evaluated by comparing their full scan LC-HR-MS profiles with those of known samples with known ME. ME can be corrected by following SAM with AM-XIC quantitation if necessary.     

采用UHPLC-QTOF-MS技术筛选亚麻籽油脂质分子标志物

为了探究亚麻籽油中脂质的真实属性和发掘其有价值的脂质分子,该研究基于超高效液相色谱-四级杆飞行时间质谱联用技术（Ultra High Performance Liquid Chromatography-Quadrupole Time-of-Flight Spectroscopy, UHPLC-QTOF-MS）表征了亚麻籽油的脂质轮廓。结果表明：在正离子模式下检测到15个脂质分子小类共668种脂质分子;在负离子模式下检测到31个脂质分子小类共404种脂质分子;共有7个脂质分子小类脂质在正、负离子下均被检测到;甜菜碱脂、甘油糖脂、神经节苷脂、鞘磷脂、神经酰胺、羟基脂肪酸的脂肪酸酯、酰基肉碱和植物固醇在亚麻籽油首次在该研究中被发现,它们都具有特殊的生物学功能。多元变量统计分析结果表明每两个品种亚麻籽油间相对定量值差异显著的脂质分子均超过200种（P<0.05）,并筛选出6种甘油磷酸肌醇、1种甘油磷酸胆碱、1种甘油磷酸乙醇胺和1种三酰基甘油作为亚麻籽A油的标志性脂质分子;6种三酰基甘油和1种半单酰基甘油磷酸酯作为亚麻籽B油的标志性脂质分子;1种神经节苷脂和1种硫代异鼠李糖甘油二酯作为亚麻籽C油的标志性脂质分子。总之,该研究在亚麻籽油中鉴定出39个脂质分子小类共1 072种脂质分子,其中有22个脂质分子小类共415种脂质分子首次在亚麻籽油中被检测到,此外不同品种亚麻籽油在脂质分子层面存在显著差异（P<0.05）,这些脂质分子作为标志物,可用于植物油的品质判别、营养评价,真伪鉴别和安全性评价等,同时该研究也为其他植物油的分析提供方法参考。     

热带糙海参雌、雄亲参的差异代谢物和差异代谢通路研究

本研究基于LC-MS/MS代谢物分析方法,探究了糙海参(Holothuria scabra)体腔液中性别特异性代谢物,同时分析了代谢通路的性别差异.结果显示,与雄性糙海参(M)相比,在雌性糙海参(F)的体腔液中共筛选出1352个上调代谢物和943个下调代谢物.根据数据库比对和注释,共筛选出66个具有显著差异的代谢物(P...     

鸡弱精症相关精浆蛋白组分析

旨在对鸡精浆蛋白组进行分析,筛选与弱精症相关的蛋白。本试验选择同批次孵化的宁都黄鸡公鸡进行精液品质检测,每隔3 d进行1次镜检,共进行3次。选择前向精子比例<20%,且直线前向精子比例<10%的个体作为试验样本,前向精子比例>80%,且直线前向精子比例>40%的个体为对照样本,每组各4只。利用液相色谱-质谱（LC-MS/MS）技术开展鸡精浆蛋白组学的研究,筛选与弱精症相关的差异蛋白。结果显示,宁都黄鸡弱精组的精子活力和密度极显著低于对照组（P<0.01）。两组间共筛选到差异表达蛋白78个,5个差异蛋白在弱精组中表现为上调,其余差异蛋白表现为下调。角蛋白9（KRT9）和硒蛋白P-2（SEPP2）仅在弱精组中检测到表达;4-羟基-2-氧戊二酸醛缩酶（HOGA1）、苯丙氨酸羟化酶（PAH）和卵磷脂胆固醇酰基转移酶（LCAT）仅在对照组中检测到表达。经GO注释和KEGG通路分析,差异蛋白功能集中于新陈代谢、糖酵解、碳代谢和氨基酸合成等生物途径。本研究筛选的宁都黄鸡弱精症和正常公鸡精浆差异表达蛋白可作为今后鸡弱精症筛查和治疗的候选靶点,通过进一步功能分析与验证为阐明弱精症的发病机理提供依据。     

替米考星在黄羽肉鸡组织中残留消除规律研究

在常规饲养条件下,以200 mg/kg替米考星剂量水平添加到饲料中饲喂4种黄羽肉鸡,连续饲喂5d,停药后6h,1、3、5、7、10、14 d每1品种肉鸡分别宰杀5只,采集每只鸡的肌肉和肝脏组织,用高效液相色谱-串联质谱法进行残留量测定.结果表明,替米考星主要残留于肉鸡的肝脏组织中;肌肉、肝脏中替米考星残留消除速率相似.停药14 d后,肌肉、肝脏中替米考星残留量均低于最高残留限量.建议替米考星在黄羽肉鸡临床休药期以20 d为宜.     

Effect of nitrogen fertilization on Fusarium head blight in spring barley

Nitrogen fertilization has been shown to influence the occurrence and the impact of Fusarium head blight in wheat. It also plays a key role in adjusting barley quality to the requirements of the malting industry, implying specific contents of protein. The present study investigated the effect of nitrogen input on the incidence of relevant Fusarium species in spring barley under field and greenhouse conditions. Grain material from differently fertilized field plots was analyzed for fungal DNA and mycotoxins by qPCR and LC-MS/MS, respectively. Under natural pathogen pressure no effect of nitrogen on infection was observed. When pathogen pressure (Fusarium culmorum and Fusarium avenaceum) was increased via species-specific soil-surface inoculation, nitrogen application reduced contents of Fusarium DNA and mycotoxins in barley grain. Nitrogen-dependent canopy parameters were recorded over the season and correlated with DNA and mycotoxin data. Apparently, sparser canopy permitted more Fusarium infections in unfertilized plots. In addition, well nitrogen-fertilized plants allowed less fungal development in the barley spike after spray inoculation in the greenhouse. These results suggest that nitrogen fertilization restricts Fusarium grain infection of barley by influencing canopy characteristics and possibly plant physiology.     

超高效液相色谱——串联质谱内标法测定兔肉中三聚氰胺含量

本文的主要目的在于建立一种准确、可靠的方法来测定兔肉中的三聚氰胺,为此,我们在LC-MS/MS检测三聚氰胺的分析过程中引入了三聚氰胺-15N3作为内标物。它对于分析全过程中所导致的目标物损失给予了完全的校正,改善了方法的精密度。样品经乙腈水加盐酸提取目标分析物,经MCX柱净化分离,选择反应监测（SRM）正离子模式测定。该方法的检测限为0.05ug/kg,在10.0-500ng/ml时峰强度与质量浓度的线性关系良好（r为0.99995）。方法的平均回收率为80-118%。