Glucose and lipid metabolism disorders in the chickens with dexamethasone‐induced oxidative stress

The purpose of this study was to investigate the effects of long‐term treatment with dexamethasone (DEX) on the antioxidation and nutrition metabolism in broiler chickens. Broilers were placed on a high‐nutrient diet for 41 days, and half were given orally DEX‐supplemented water at 20 mg/L every other day from 19 to 41 days of age. DEX treatment downregulated superoxide dismutase activity as well as the mRNA expression of CuZn‐superoxide dismutase and glutathione peroxidase with a decrease in GSH/GSSG ratio and an increase in malondialdehyde level in the liver of broilers. DEX treatment aggravated oxidative damage in the liver and, therefore, increased the sensitivity of broilers to ascites syndrome with higher mortality and reduced growth performance. Serum metabolomics analysis showed that DEX treatment significantly increased the levels of glucose, intermediates in protein metabolism (valine, proline, serine, threonine and urea) and lipid metabolism‐related products (palmitic acid, stearic acid and cholesterol) while decreasing the levels of β‐hydroxy butyric acid, succinic acid and malic acid, demonstrating that DEX treatment inhibited the Krebs cycle and the oxidation of fatty acids, and promoted the de novo synthesis of fatty acids as well as protein decomposition in the liver of broilers. Additionally, detection of metabolism‐related enzymes revealed that DEX treatment inhibited glycolysis and promoted glycogen decomposition. In summary, DEX treatment resulted in oxidative stress and glucose and lipid metabolism disorders in the broilers.     

Non‐invasive assessment of culture media from goat cloned embryos associated with subjective morphology by gas chromatography – mass spectroscopy‐based metabolomic analysis

Pre‐implantation embryo metabolism demonstrates distinctive characteristics associated with the development potential of embryos. We aim to determine if metabolic differences correlate with embryo morphology. In this study, gas chromatography – mass spectroscopy (GC‐MS)‐based metabolomics was used to assess the culture media of goat cloned embryos collected from high‐quality (HQ) and low‐quality (LQ) groups based on morphology. Expression levels of amino acid transport genes were further examined by quantitative real‐time PCR. Results showed that the HQ group presented higher percentages of blastocysts compared with the LQ counterparts (P < 0.05). Metabolic differences were also present between HQ and LQ groups. The culture media of the HQ group showed lower levels of valin, lysine, glutamine, mannose and acetol, and higher levels of glucose, phytosphingosine and phosphate than those of the LQ group. Additionally, expression levels of amino acid transport genes SLC1A5 and SLC3A2 were significantly lower in the HQ group than the LQ group (P < 0.05, respectively). To our knowledge, this is the first report which uses GC‐MS to detect metabolic differences in goat cloned embryo culture media. The biochemical profiles may help to select the most in vitro viable embryos.     

基于LC-MS技术研究氟氯苯氰菊酯对西方蜜蜂工蜂幼虫代谢的影响

【目的】氟氯苯氰菊酯（flumethrin）属于第二代拟除虫菊酯类杀虫、杀螨剂,应用于蜂群除螨。由于杀螨剂具有一定的毒性,在杀死螨虫的同时也会威胁到蜜蜂的健康。本研究采用液相色谱-质谱联用技术（LC-MS）检测氟氯苯氰菊酯处理后的西方蜜蜂工蜂幼虫代谢物,筛选差异代谢物,并分析涉及到的代谢通路,研究氟氯苯氰菊酯对蜜蜂的毒理作用,为蜜蜂饲养提供参考。【方法】控制蜂王在空的工蜂巢脾上产卵12 h,并将产卵区域分为4组,从第5天开始分别给各组小幼虫饲喂含氟氯苯氰菊酯的糖水（0、0.5、5、50 mg·kg^-1）,剂量从第5天至第8天逐日递增（1.5、2、2.5、3 μL）,第9天采集幼虫的淋巴液。运用代谢组学中的LC-MS技术分析蜜蜂幼虫的代谢物,结合主成分分析（PCA）、偏最小二乘法-判别分析（PLS-DA）,筛选差异显著的代谢物,并对氟氯苯氰菊酯处理组和对照组间共同差异代谢物进行代谢通路分析。【结果】0.5 mg·kg^-1组与对照组相比,共有差异代谢物190种,共鉴定87种;5 mg·kg^-1组与对照组相比,共有差异代谢物275种,共鉴定97种;50 mg·kg^-1组与对照组相比,共有差异代谢物275种,共鉴定131种。从鉴定的差异代谢物中筛选到29种氟氯苯氰菊酯处理组共同差异代谢物,其中16种代谢物上调,12种代谢物下调,1种代谢物在0.5和50 mg·kg^-1组中下调,在5 mg·kg^-1组中上调。这些差异代谢物包括核糖、嘌呤及其衍生物、脂肪酸及其偶联物等。经代谢通路富集分析,发现差异显著（P＜0.05）的代谢通路包括氨基糖和核苷酸糖代谢、药物代谢-其他酶类、α-亚麻酸代谢等途径。【结论】LC-MS技术能够有效地分析氟氯苯氰菊酯影响下蜜蜂幼虫代谢物的变化,氟氯苯氰菊酯会引起蜜蜂幼虫体内尿苷二磷酸-N-乙酰葡糖胺、硫唑嘌呤、愈伤酸、9-羟基壬酸、氢过氧化亚油酸等物质含量异常,这些差异代谢物的变化证实了氟氯苯氰菊酯引起蜜蜂体内各种物质代谢紊乱,对这些代谢过程分析可进一步阐释蜜蜂代谢有毒化合物的机制,并为杀螨剂及其他有毒化合物对蜜蜂的胁迫提供理论依据。     

Neotropical mustelids: fecal metabolome diversity and its potential for taxonomic discrimination

Chemical profiles of non-invasive biological material, such as feces, have great potential to study elusive animals or those with low population densities. Here, we use a metabolomic approach to evaluate Neotropical mustelids as a biological model to describe the diversity of the metabolites present in fecal samples, as well as to evaluate the potential of chemical profiles for taxonomic discrimination. We collected fecal samples from captive individuals of 5 species of mustelids occurring in Brazil and analyzed them by liquid chromatography coupled to high-resolution mass spectrometry. Over 200 compounds have been annotated; “bile acids, alcohols and derivatives” was the most expressive class in the metabolome of all the species. We successfully discriminated 3 taxonomic groups: 1—tayra (Eira barbara); 2—otters (Lontra longicaudis and Pteronura brasiliensis; 1); and 3—grisons (Galictis vittata and Galictis cuja). Several compounds seemed to be associated with food intake and the digestive process, while others were found for the first time in Neotropical mustelids. We concluded that mustelids show high metabolome diversity and that species-specific identification through metabolomic profiles is possible, thus contributing to the development and implementation of additional non-invasive approaches in the study of mustelids.     

荷斯坦牛高、低乳脂率牛乳代谢组分析

旨在筛选牛乳不同乳脂水平潜在标志性差异代谢物。本研究中乳样采自宁夏农垦贺兰山奶业茂盛牧场,采集体重与月龄相近且健康的头胎次荷斯坦牛泌乳中后期(180~210 d)的早、中、晚班次新鲜乳样(4∶3∶3混合)245份。DHI测定后筛选体细胞数低于20万个·mL^-1,乳脂率具有极端差异的样品26份,其中乳脂率大于4.4%为高乳脂率组(HF组,13份),乳脂率小于3.0%为低乳脂率组(LF组,13份)。之后采用超高效液相色谱-质谱法(UHPLC-MS)对样品进行代谢组学分析。偏最小二乘法-判别分析(PLS-DA)结果显示,相对于LF组,HF组代谢轮廓发生了变化,在HF与LF两组中共鉴定出343种代谢产物,根据VIP值(VIP>1)和单变量统计分析(P<0.05),正、负离子模式下共筛选出60种显著差异代谢物(P<0.05);其中依据P<0.5且FC>2.0及P<0.5且FC<0.5,HF组奶样中15种代谢物含量高于LF组,6种代谢物含量低于LF组;进一步通过ROC曲线下面积AUC>0.85,发现有18种差异代谢物对两组牛乳具有显著区别能力,即：N-油酰甘氨酸、皮质醇、δ-生育酚、PC(14∶0e/9∶0)。结果发现,不同乳脂水平显著差异代谢物有60种,且代谢物N-油酰甘氨酸、皮质醇、δ-生育酚、PC(14∶0e/9∶0)可作为高乳脂率牛乳潜在标志性差异代谢物。本研究结果为奶牛乳脂合成提供了有价值的理论依据,同时也为研究奶牛的泌乳过程提供了资料。     

微生物代谢组学研究方法

代谢组学是后基因纰时代新兴的一种研究生物样品中所有小分子代谢物的技术,是系统生物学的有机组成部分,并在近年来取得很大进展.该文就微生物代谢组学研究中有关样品制备、代谢产物分析鉴定和数据分析等涉及的主要方法进行了概述,并用一些典型实例介绍微生物代谢组学的应用,对微生物代谢组学研究中潜在的问题和未来发展趋势进行了讨论.     

Differential metabolic response of barley genotypes,varying in resistance,to trichothecene‐producing and ‐nonproducing (tri5−) isolates of Fusarium graminearum

Resistance of barley to Fusarium graminearum was studied using a pair each of resistant and susceptible black and yellow barley lines. The spikelets were inoculated with a trichothecene‐producing isolate, a trichothecene‐nonproducing isolate (tri5^?), or a mock solution. Spikelets were collected 72 h after inoculation and metabolites were analysed using a LC‐hybrid MS system. Metabolite abundances were used to identify the constitutive (RRC) and induced resistance‐related metabolites (RRI). The pathogen virulence factor, DON, and its plant detoxification product, DON‐3‐O‐glucoside (D3G), were also identified and designated as resistance‐indicator (RI) metabolites. The RRC, RRI and RI metabolites were putatively identified. Jasmonic acid was significantly induced in barley following inoculation with a trichothecene‐producing isolate, but not with a tri5^? isolate. The former isolate reduced the induction of both the number and amount of RR metabolites. The metabolites cinnamic acid, sinapoyl alcohol, coniferin, catechin and naringin were identified only in response to the inoculation with a tri5^? mutant. The abundances of p‐coumaric acid, coniferaldehyde and sinapaldehyde increased more in response to the tri5^? mutant than to the trichothecene‐producing isolate. The total amount of DON synthesized and its conversion to D3G varied greatly between the resistant and susceptible black barley, but not in yellow barley. Interestingly, an increase in the amount of total DON produced was associated with a decrease in the conversion of DON to D3G. The roles of RRC, RRI and RI metabolites in plant defence and their further use as potential biomarkers in screening are discussed.     

转基因作物的非预期效应及其检测

随着转基因产业的飞速发展,转基因食品的安全性逐步引起人们的广泛关注.外源基因的非预期效应可能引起转基因食品的营养成分发生改变,甚至产生一些新的毒性物质,可能对人类和动物健康以及环境形成潜在的危害,是转基因食品安全性评价的重要内容之一.由于外源基因的非预期效应具有潜在性,非预见性,因此以“实质等同性”为基础的定向评价方法很难充分考虑到由遗传修饰引起的非预期效应.文章主要阐述了转基因植物整合位点的分布和机制、转基因作物可能产生的非预期效应,以及利用基因芯片技术、蛋白质组定量分析技术、代谢组分析技术分别从mRNA水平、蛋白质水平、代谢水平上比较转基因作物和非转基因作物基因表达的差异,在食品安全评价中会是完善定向方法的补充方案,对转基因食品的安全性评价至关重要.