浅谈二噁英的检验技术

1　检测二口恶英的技术难度食品和饲料中二口恶英及其类似物的检验属于超痕量级检验,通常以ｎｇ/ｋｇ和ｐｇ/ｋｇ表示。它比其他污染物含量低千倍到亿倍以上,检测难度很大,其多组分即同系物、异构体的化学前处理技术几乎包罗近代最先进的手段,涉及分离、富集、提取、净化、清洗和浓缩装置,还包含自动凝胶色谱(ＡｕｔｏｍａｔｅｄＧｅｌＰｅｒｍｅａｔｉｏｎＣｈｒｏｍａｔｏｇｒａｐｈｙ)、反相ＨＰＬＣ、玻璃色谱柱等。检测过程需要尖端大型分析仪器的支持,定量分析依靠ＨＲＧＣ/ＨＲＭＳ,对仪器的灵敏度、选择性和特异性要求极高,是现今分…     

绿色富硒牧草饲料作物生产技术规程

本规程规定了绿色富硒牧草饲料作物的生产基地环境、种植区域分布、生产管理、刈割利用、票证管理等内容,并制定了牧草饲料作物硒含量达到0.01～0.1mg/kg的产品标准.     

HPLC法测定盐酸氯苯胍原粉含量

目的：采用高效液相色谱法测定盐酸氯苯胍的含量。方法：样品经1％盐酸甲醇萃取．以SHIMADZUC8色谱柱（250mm×4．6mm,5μm）分离,甲醇和2．5％的磷酸溶液以体积比75比25的混合液为流动相,在检测波长为317nm处测定。结果：峰面积与盐酸氯苯胍的质量浓度在1—100．0mg·L^-1范围内呈线性关系。标准加入回收率为（n=6）95．2％,相对标准偏差（n=5）小于0．5％。     

鸡球虫耐药性的机理检测方法及其延缓措施

文章对鸡球虫耐药性的产生机制、检测方法及其延缓措施的研究进展进行了概述。     

Expression and Bioinformatic Analysis of ADIPOQ Gene in Hanper Sheep

The aim of this study was to investigate the expression and biological characteristics of adiponectin (ADIPOQ) gene in longissimus dorsi muscle of Hanper sheep at different months of age.The ADIPOQ gene mRNA expression was detected in longissimus dorsi muscle of Hanper sheep at 3 different growth periods (1,7 and 13 months old) by Real-time quantitative PCR.The bioinformatics method was used to analyze the nucleotide and amino acid sequences of ADIPOQ gene,protein characteristics and network interaction protein.The results showed that ADIPOQ gene was expressed in longissimus dorsi muscle of Hanper sheep,which showed an increasing trend with the growth of the months age without significant difference (P>0.05).There was higher homology of ADIPOQ gene with Capra hircus (98.60%,99.00%) and Bos taurus (98.60%,87.00%) in nucleotide and amino acid sequences.The results of physical and chemical properties analysis showed that the molecular formula of ADIPOQ protein was C₁₁₇₂H₁₇₇₆N₃₁₄O₃₄₉S₅,the molecular mass was 26.00 ku,and the theoretical isoelectric point (pI) was 5.88,which suggested that the protein was acidic.The average value of ADIPOQ hydrophilic protein (GRAVY) was －0.403,which indicated that the protein was hydrophilic and didn’t belong to transmembrane protein.In addition,the signal peptide sequence was Met¹-Ala¹⁷,and the cleavage site was between Ala¹⁷ and Arg¹⁸.ADIPOQ existed collagen structure domain and C1Q conserved structure domain at position 45－101 and 101－237,respectively.The secondary structure mainly composed of random coil (66.95%).The construction of protein interaction network indicated that ADIPOQ might interact with ADIPOR1,ADIPOR2,CDH13 and LEP.The results provided a theoretical basis for further exploring the molecular biological functions of ADIPOQ gene in the process of muscle development in Hanper sheep.     

Use of comparative proteomics to identify the effects of creatine pyruvate on lipid and protein metabolism in broiler chickens

Four hundred male chickens were selected to study the effects of pyruvate (Pyr), creatine pyruvate (CrPyr) and creatine (Cr) on the expression of hepatic mitochondrial and cytoplasm proteins associated with lipid and protein metabolism. Mitochondrial purification was accomplished using the two-step differential centrifugation and density gradient method, and the activities of organelle-specific marker enzymes were determined to assess the purity of the mitochondria. Proteins were extracted and fractionated by two-dimensional electrophoresis and the differential protein spots were assessed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. CrPyr reduced fatty acid accumulation by down-regulating adipose differentiation-related protein, inhibited ATP synthase expression, and reduced cholesteryl ester transfer protein (CETP) expression, thus reducing the levels of high density lipoprotein and triglycerol (TG) levels (thereby lowering fat and cholesterol deposition). CrPyr increased the expression of eukaryotic translation initiation factor (eIF) 2B, calreticulin (CRT) and eIF3a, thus promoting protein synthesis. CrPyr up-regulated the expression of fatty acid-binding proteins, CETP and apolipoprotein A-IV in cytoplasmic extracts, and these proteins accelerated the decomposition of fatty acids and TG, thus reducing fat deposition. In conclusion, CrPyr plays an important role in lipolysis and protein synthesis, and this effect was more pronounced than was the effect of Pyr and Cr.     

Morphological study of Socorro Island Merino sheep and its crosses with hair breeds

Tropical Animal Health and Production - A study was conducted with the objective to characterize the morphology of Socorro Island Merino sheep. A total of 67 sheep, 62 females, 26 purebred and 36...     

蒺藜苜蓿叶绿体密码子偏好性分析

本文对蒺藜苜蓿叶绿体基因组全序列密码子进行分析,筛选出50条CDS(coding DNA sequence)利用CodonW软件进行分析其密码子使用模式。结果显示,蒺藜苜蓿叶绿体基因组密码子第3位碱基GC含量为26.9%,即第3位密码子富含A和U,ENC值在37.11~51.91之间密码子偏好性较弱。相对同义密码子使用度分析显示RSCU值大于1的密码子有23个,其中以A和U为结尾20个。中性绘图分析显示GC₁₂与GC₃的相关系数为0.341,相关性不显著,回归系数为0.4843;单基因ENC比值多分布在-0.05~0.05,即大部分基因ENC值离ENC期望值较近;对应性分析,第一轴显示了12.50%的差异为主要影响因素,第一轴与ENC和GC₃的相关系数分别为0.091和-0.092,均相关不显著。综合这几项分析发现蒺藜苜蓿叶绿体基因组密码子偏好性主要受到突变的影响,但是并不是唯一的影响因素,其他因素对密码子偏好性也可能有一定的影响。最终通过高表达优越密码子方法确定得出UUA、UUG、CCU等23个密码子为最优密码子,为之后对外源基因进行改造,提高其在叶绿体中的表达效率奠定了基础。     

ADSL基因启动子区遗传变异与鸡肉冻藏新鲜度的相关性分析

试验旨在探究鸡腺苷琥珀酸裂解酶（adenylosuccinate lyase,ADSL）基因启动子区多态性及其与鸡肉冻藏新鲜度的相关性。以161只青脚麻鸡为研究对象,通过DNA混池测序法检测ADSL基因启动子区遗传变异。采用等位基因特异性PCR完成个体基因型分析,并分析了各基因型与鸡胸肌肉色、体重及胸肌冷冻60 d后新鲜度K值和pH的相关性。结果显示,在ADSL基因启动子区ATG上游1 670 bp处发现1个SNP位点（c.-1670 C>A）,其AA基因型个体肌肉冷冻60 d后新鲜度K值（23.61%）极显著低于CA（33.00%）和CC（33.56%）基因型（P<0.01）,即冻藏60 d后AA基因型个体肌肉较CA和CC基因型新鲜,CA和CC基因型间新鲜度K值差异不显著（P>0.05）;各基因型间鸡体重、胸肌肉色及胸肌冷冻60 d后pH均无显著差异（P>0.05）。生物信息学预测发现,c.-1670 C>A导致ADSL基因启动子区转录因子结合位点的显著改变,该突变位点可能造成ADSL基因的表达差异。综上,ADSL基因启动子区c.-1670 C>A与青脚麻鸡胸肌冷冻60 d后新鲜度K值具有显著相关性,该位点可作为青脚麻鸡肉品新鲜度的候选分子遗传标记。