Simultaneous detection of multiple mycotoxins in broiler feeds using a liquid chromatography tandem-mass spectrometry

Mycotoxins are secondary fungal metabolites that are typically present in grain and feed ingredients used for animal feeds. An analytical method using LC-ESI-MS/MS was developed to quantify nine mycotoxins, consisting of aflatoxin B₁ (AFB₁), AFB₂, AFG₁, AFG₂, T-2 toxin, deoxynivalenol (DON), nivalenol (NIV), zearalenone (ZEA) and ochratoxin A (OTA) in broiler feeds. In total, 100 samples of broiler feeds were collected from poultry farms in Central Thailand. The survey found that AFB₁ and ZEA were the most prevalent mycotoxins in the feed samples at percentages of 93% and 63%, respectively. The limit of detections (LODs) of investigated mycotoxins was 0.20–0.78 ng/g. AFB₂, DON, AFG₁, NIV and T-2 toxin were also detectable at low contamination levels with percentages of 20%, 9%, 7%, 5% and 1%, respectively, whereas OTA and AFG₂ were not detected in any of the feed samples. These results suggest that there is a very low level of risk of the exposure to mycotoxins in feeds obtained from broiler farms in Central Thailand.     

高粱光敏色素A基因的克隆、蛋白结构与长短日照诱导表达模式

光敏色素是一类红光/远红光受体,对植物光形态建成、外部形态和生理功能等方面起着重要的调节作用。为明晰光敏色素A在调控高粱光形态建成发育过程中的作用,本研究比较分析光温敏感程度不同的高粱品种Btx623、Rio、Tx430和LH645的PhyA基因序列和PHYA蛋白的保守结构域,利用qRT-PCR明确长短日照条件处理下PhyA基因的表达模式。结果表明,Btx623、Rio和Tx430之间PhyA基因序列存在非同义突变,LH645在PhyA基因的第7个外显子上插入了5 bp碱基序列;高粱PhyA蛋白中含有1个PAS-2结构域、1个GAF结构域、1个Phytochrome结构域、2个PAS结构域、1个组氨酸激酶A结构域和1个类似组氨酸激酶的ATP激酶结构;遗传进化树分析表明,单子叶和双子叶植物PhyA蛋白明显聚为2大类,高粱PhyA、谷子PhyA和玉米PhyA1、PhyA2聚为一个亚类,相互间亲缘关系较近,与水稻PhyA同源性相对较远;在短日照(SD)条件下各时期PhyA基因转录水平变化显著,Rio PhyA基因转录水平较Btx623和Tx430变化明显,LH645 PhyA基因转录变化不显著,在长日照(LD)条件下Rio PhyA基因转录水平低于Btx623和Tx430,LH645 PhyA基因转录水平变化不显著。以上结果表明,PhyA受光周期诱导,推测其在高粱光形态建成中起重要调控作用。本研究为进一步解析PhyA基因功能及其在调控高粱光形态建成发育过程中的作用提供理论基础。     

砂藓(Racomitrium canescens)抗旱相关基因RcAOS2的克隆及表达分析

丙二烯氧化物合酶(allene oxide synthase, AOS)是茉莉酸合成途径中关键酶,在茉莉酸合成中具有重要的作用。本研究在砂藓(Racomitrium canescens)干旱胁迫转录组数据中发现一个干旱胁迫下表达量上调的AOS基因,将其命名为RcAOS2,我们对RcAOS2的开放阅读框进行了克隆及相关的生物信息学预测分析,并对RcAOS2在砂藓快速脱水和复水过程中的表达量变化进行了检测。结果显示,该基因cDNA全长1 474 bp,开放阅读框长516 bp。RcAOS2编码蛋白质的相对分子质量为4.36 kD,等电点为5.11,不稳定系数为55.02,为不稳定蛋白质;脂肪系数为19.19;RcAOS2蛋白质疏水性较强,属于疏水性蛋白质,存在信号肽,不属于跨膜蛋白质。系统进化分析表明,RcAOS2蛋白质与其他物种AOS蛋白质亲缘关系较远,是具有AOS序列特征的新类型。实时荧光定量PCR分析结果表明RcAOS2基因在砂藓干旱和复水过程中呈现差异性表达,推测RcAOS2可能参与砂藓的干旱胁迫响应和复水回复过程。本研究成果为进一步研究砂藓抗旱基因功能提供理论基础和备选基因资源。     

湖南永州尖吻蝮蛇蛇毒的蛋白组分及毒性分析

采用Nano–LC–ESI–MS/MS蛋白鉴定技术对湖南永州尖吻蝮蛇蛇毒蛋白组分进行质谱分析,应用常规体外试管法对尖吻蝮蛇蛇毒体外溶血值进行检测,采用改良寇式法对尖吻蝮蛇蛇毒LD_(50)进行测定。结果显示:尖吻蝮蛇蛇毒含有50种蛋白,蛋白相对分子质量集中在1.0×10~4～2.0×10~4(46.9%)、4.0×10~4～5.0×10~4(22.4%)、2.0×10~4～3.0×10~4(10.6%)和7.0×10~4～8.0×10~4(7.6%),其中代表性的高丰度蛋白有蛇毒金属蛋白酶A(11.7%)、蛇毒金属蛋白酶H1(9.8%)、蕲蛇类凝血酶–2(7.3%)、抗凝血酶A–A亚基(6.8%),低丰度蛋白(0.1%)有Ecto–5'–核苷酸酶、碱性磷脂酶A2 DAV–N6、生长分化因子11;蛇毒引起红细胞溶血的最低质量浓度为60.00μg/mL,尖吻蝮蛇蛇毒对KM小鼠的LD_(50)为7.1796mg/kg,攻毒小鼠出现呼吸急促、躁动不安、注射部位出现奇特瘙痒和大面积溃烂,至死亡。     

酸奶营养品质提升的加工工艺研究

牛奶中含有丰富的活性营养物质,包括乳铁蛋白、免疫球蛋白、乳过氧化物酶、α-乳白蛋白、β-乳球蛋白等。传统工艺生产的酸奶经过高温杀菌,活性营养物质几乎完全损失。为了避免这一情况,本文推出一种新的酸奶生产工艺,生产出的酸奶可保留大部分活性营养物质。首先将牛奶的乳脂进行分离,乳脂部分进行125 ℃、5 s杀菌,脱脂牛奶部分进行75 ℃、15 s杀菌,将两部分料液混合后加入菌种发酵至酸度75~85°T,破乳后冷却后熟8 h以上。经测定,新工艺酸奶中α-乳白蛋白、β-乳球蛋白、乳铁蛋白、免疫球蛋白、乳过氧化物酶含量分别为966 mg/L、1 963 mg/L、23.4 mg/L、102 mg/L、1 025 U/L,远高于传统工艺酸奶的68 mg/L、200 mg/L、0.7 mg/L、14 mg/L、0 U/L。通过对比新工艺与传统工艺酸奶保质期内的活菌数、黏度、酸度和口感,并无显著差异。     

Effect of eleutheroside B/E on proliferation and expression of PPARγ and TGF-β1 in HBZY-1 cells cultured with high glucose

AIM: To explore the effects and mechanism of eleutheroside (ETS) B or E on the proliferation of HBZY-1 cells treated with high glucose. METHODS: The HBZY-1 cells were cultured under high glucose condition. The 4th generation of HBZY-1 cells was used for determining the optimal cell density, which was consistent with the growth regulation curve of the cells. The cells were divided into 6 groups: low glucose (LG) group, high glucose (HG) group, high glucose plus ETS-B/E (low dose, medium dose and high dose) groups, and high glucose plus losartan (LTG) group. After all cells were treated with the corresponding drugs at 24 h, 48 h and 72 h, the inhibitory rate of the proliferation was measured, and the expression of TGF-β1 and PPARγ was detected by immunocytochemistry and Western blotting. RESULTS: The best cell density was 2 000 cells/well, which was complied with the basic rules of the cell growth, and high glucose significantly promoted the HBZY-1 cell proliferation. At each time point, the inhibitory effects of ETS-B/E were significantly different between HG group and LTG group on the proliferation of the HBZY-1 cells (P<0.05). The expression of TGF-β1 was significantly inhibited, and the expression of PPARγ was significantly promoted by ETS-B/E (P<0.05). ETS-E showed stronger effect than ETS-B (P<0.05) in a concentration- and time-dependent manner. CONCLUSION: ETS-B/E significantly inhibits the proliferation of HBZY-1 cells under high glucose condition by decreasing TGF-β1 expression and promoting PPARγ expression.     

杧果‘汤米·阿京斯’香气特征分析

以杧果品种‘汤米·阿京斯’的叶片和果肉为材料，通过固相微萃取结合气相色谱/质谱法，分析和鉴定挥发性物质的组成。分别检测出叶片和果肉中挥发性物质64和51种。果肉中的主要挥发性成分为萜烯类化合物和苯甲醛；果肉中所特有的且含量较高的香料物质为3-蒈烯和苯甲醛，二者含量占56.68%。对果肉中挥发性物质的香味进行分析，结果发现其包含14种香型，其中果香、松香和木香是最主要的香韵类型，对松香味有贡献的化合物包括α-蒎烯、β-蒎烯、3-蒈烯、月桂烯和α-水芹烯，其中3-蒈烯贡献最大。     

两型社会建设背景下生态效率评价研究——以湖南省为例

基于"两型"社会建设的目标与内涵,选取了湖南省生态效率综合评价指标,以2003—2012年湖南省数据为样本,采用DEA数据包络分析法计算各年份的生态效率,并对不同年份的能源消耗量、水资源消费量以及三废的排放量进行深入分析。结果表明,随着湖南省GDP的增长,生态效率也不断在提高。针对不同的资源产出率和环境产出率,湖南省应树立可持续发展理念,实现经济由粗放型发展向集约型发展转变;发展创新技术,推进湖南省两型社会的发展;完善法律法规体系,加大宣传力度,改变保守观念,提高人们的环保意识。     

气相色谱-串联质谱法测定柑橘中5种杀螨剂残留

建立了气相色谱-串联质谱法(GC-MS/MS)检测柑橘中5种杀螨剂残留分析方法。样品经乙腈提取、氯化钠盐析后,取有机相用Qu EChERS方法净化,利用GC-MS/MS在多反应监测(MRM)模式下进行测定,外标法定量。5种杀螨剂在0.005~0.5mg/L浓度范围内呈现良好的线性关系,相关系数r^2均>0.996,方法定量限为0.005 mg/kg。在0.005、0.01和0.1mg/kg 3种添加水平下,加标回收率为70.6%~111.3%,相对标准偏差(RSD)为1.07%~14.64%。本方法简便、重现性良好,可用于柑橘类水果样品中杀螨剂的日常检测。