Comparative analysis of three tetrachloroethene to ethene halorespiring consortia suggests functional redundancy

Three anaerobic, dechlorinating consortia were enriched from different sites using methanol and tetrachloroethene (PCE) and maintained for approximately 3 years. These consortia were evaluated using chemical species analysis including distribution of dechlorination products, production of organic acids and methane, and using qualitative and quantitative PCR (qPCR), terminal restriction fragment length polymorphism (TRFLP), and denaturing gradient gel electrophoresis (DGGE) with primers specific to Dehalococcoides 16S rRNA gene sequences. TRFLP and analysis of organic acids revealed differing fermentative populations in each consortium, which were dominated by acetogens. Monitoring methane production combined with qPCR for archaea showed that complete dechlorination of PCE-to-ethene occurred in the presence and absence of methanogens. The 16S rRNA gene-based analyses demonstrated that enrichment with PCE resulted in dechlorinating communities dominated by Dehalococcoides and Dehalobacter, and that up to four different PCE-dechlorinating organisms coexisted in one consortium. Further, the DGGE analysis suggested that at least one consortium contained multiple Dehalococcoides strains. The combined analysis of 16S rRNA and reductive dehalogenase genes suggested that one consortium contained a member of the Dehalococcoides "Cornell" group with the ability to respire VC.     

Comparative analysis of promoter regions containing binding sites of the heterodimeric transcription factor Ino2/Ino4 involved in yeast phospholipid biosynthesis

The inositol/choline responsive element (ICRE) functions as a UAS element mediating coordinate expression of structural genes required for yeast phospholipid biosynthesis. However, ICRE motifs could be detected upstream of various genes apparently not involved in lipid metabolism. In this work we investigated the expression pattern of selected genes containing ICRE promoter motifs, as identified by in silico analysis (ARG4, ERG20, FAR8, GPD2, RSF1, URA8, VHT1 and YEL073C). It turned out that the presence of an ICRE upstream of a gene of unknown function indeed allows to conclude for regulation by phospholipid precursors, which is mediated by activators Ino2/Ino4 and the repressor Opi1. We also demonstrated in vitro binding of Ino2/Ino4 heterodimers to promoter regions. Thus, our analysis supports the view that identification of regulatory elements by a database search provides evidence for a specific pattern of gene expression. Activation by pathway-specific regulators may suggest a physiological function for as yet uncharacterized genes.     

生物检测技术在食品检验中的研究

生物检测技术在食品检验中应用越来越广泛，对食品检测中的主要生物检测方法及其主要应用领域进行了综述，并对发展前景做了展望。     

Characterization of the DGAT1 mutations and the CSN1S1 promoter in the German Angeln dairy cattle population

The identification of quantitative trait loci (QTL) and genes with influence on milk production traits has been the objective of various mapping studies in the last decade. In the centromeric region of Bos taurus autosome (BTA) 14, the acyl-CoA:diacylglycerol acyltransferase1 gene (DGAT1) has been identified as the most likely causative gene underlying a QTL for milk fat yield and content. Recently, a second polymorphism in the promoter of DGAT1 emerged as an additional source of variation. In this study, the frequencies and the effects of alleles at the DGAT1 K232A and at the DGAT1 promoter variable number of tandem repeat (VNTR) locus on BTA14, and of alleles at the CSN1S1 (α_S1-casein-encoding gene) promoter on BTA6 in the German Angeln dairy cattle population were investigated. Analyzed traits were milk, fat, protein, lactose, and milk energy yield, fat, protein, lactose, and milk energy content and somatic cell score. The lysine variant of the DGAT1 K232A mutation showed significant effects for most of the milk production traits. A specific allele of the DGAT1 promoter VNTR showed significant effects on the traits lactose yield and content, milk energy content, and SCS compared with the other alleles. Additionally, a regulation mechanism between the DGAT1 K232A mutation and the DGAT1 promoter VNTR was found for fat yield and content, which could be caused by an upper physiological bound for the effects of the DGAT1 gene. At the CSN1S1 promoter, 2 of 4 alleles showed significant allele substitution effects on the milk yield traits.     

Rest before slaughter ameliorates pre-slaughter stress-induced increased drip loss but not stress-induced increase in the toughness of pork

One factor affecting meat quality is pre-slaughter stress. We investigated the effects of exercise stress on drip loss and toughness in relation to resting times of 0, 1 or 3 h following exercise on a treadmill. This exercise stress was regarded as combined physical and physiological stress. Exercise stress increased the muscle temperature, reduced the creatine phosphate, ATP and glycogen content of pigs slaughtered immediately after stress exposure. These conditions lead to a reduced pH early post mortem and an increased drip loss, while only 1 h of rest after exercise stress normalised these effects. However, an overshooting effect was noted when pigs were rested for 1–3 h before slaughter, emphasising the importance of critical control of the resting period when studying exercise stress-induced effects on meat quality. Furthermore, meat from exercise stressed pigs, irrespective of resting, had increased toughness compared to controls, indicating that the toughness was not related to drip loss in meat from exercise stressed pigs.     

Rest before slaughter ameliorates pre-slaughter stress-induced increased drip loss but not stress-induced increase in the toughness of pork

One factor affecting meat quality is pre-slaughter stress. We investigated the effects of exercise stress on drip loss and toughness in relation to resting times of 0, 1 or 3 h following exercise on a treadmill. This exercise stress was regarded as combined physical and physiological stress. Exercise stress increased the muscle temperature, reduced the creatine phosphate, ATP and glycogen content of pigs slaughtered immediately after stress exposure. These conditions lead to a reduced pH early post mortem and an increased drip loss, while only 1 h of rest after exercise stress normalised these effects. However, an overshooting effect was noted when pigs were rested for 1–3 h before slaughter, emphasising the importance of critical control of the resting period when studying exercise stress-induced effects on meat quality. Furthermore, meat from exercise stressed pigs, irrespective of resting, had increased toughness compared to controls, indicating that the toughness was not related to drip loss in meat from exercise stressed pigs.     

旋流器中分散相颗粒动力学分析

从湍流和两相流动的角度全面阐释了分散相颗粒在旋流场中的受力，重点介绍了分散相颗粒在旋流场中所受的颗粒加速度力（巴西特力、视质量力、速度波动力）和由速度梯度引起的力（马格拉斯力、滑移-剪切升力）等。并对在此受力分析基础上建立的分散性运动方程进行了简化分析，指出可以得到分散相径向速度对于径向位置的分布和径向运动特性时间。同时指出旋流场中应力的作用及其与连续相介质阻力的关系，纠正了相关文献的说法。     

双环磺草酮在稻田环境中的残留分析

目的建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定稻田环境中双环磺草酮的残留量分析方法。方法样品经0.02mol/L盐酸浸泡后,用乙腈提取,提取液经石墨化碳黑粉净化,采用乙腈和0.1%甲酸作为流动相洗脱,质谱(ESI+)采用多离子检测模式(MRM)对双环磺草酮的定量离子和定性离子进行监测。结果在0.002~10mg/L浓度范围内目标物线性良好,相关系数大于0.9999。双环磺草酮在不同水平的添加回收试验中,方法的平均回收率为78.5%~100%,相对标准偏差为0.8%~6.5%,双环磺草酮的最低检测浓度为0.002mg/kg。结论该方法灵敏度、准确度、精密度符合农药残留分析的要求。     

口罩标准比较分析

从口罩产品的分类、材料组成、标准规范比较方面进行介绍和信息整理,罗列国内各项口罩执行标准的适用范围和评价指标,同时与国外相关口罩标准技术规范中的关键性参数进行对比,为今后口罩产品的开发提供参考.     

金属硫蛋白体内抗氧化功能研究进展

金属硫蛋白(metallothionein,简称MT)是一类分子量较小的富含巯基和半胱氨酸的金属结合蛋白质,广泛存在于生物体内。大量研究证实其在参与重金属解毒,调节体内的微量元素的代谢,调控基因表达及防止机体氧化等方面具有显著效果。随着对金属硫蛋白研究的深入,其在体内抗氧化作用显著。本文综述了金属硫蛋白的结构、分类、体内抗氧化机制及其在抗氧化产品方面的应用,旨在为金属硫蛋白在体内抗氧化研究及相关抗氧化产品的开发提供理论参考。      

低聚果糖检测分析方法对比及优劣性分析

低聚果糖是一种功能性低聚糖,具有良好的生理功效,近年来,低聚果糖在食品工业中的应用范围不断扩大,利用现代检测技术对食品中低聚果糖的含量进行检测具有必要性。不同来源的低聚果糖不仅存在组分果糖链链长的不同,而且化学结构也不尽相同。本文系统地综述了近年来国内外检测低聚果糖的方法,包括高效液相色谱法、离子色谱法等较常用方法,以及分析了蔗果型低聚糖异构体的新检测手段,并总结了各自的优劣性,为低聚果糖有效、快速检测提供参考。      

Genetic analysis of cow survival in the Israeli dairy cattle population.

The linear model method of VanRaden and Klaaskate for analyzing herd life was expanded. Information on conception and protein yield was included in the estimation of predicted herd life of Israeli Holsteins. Variance components were estimated by a multitrait animal model. Heritability was slightly higher for herd life than for number of parities, but genetic correlations were close to unity. Animal model heritability estimates of herd life were higher than were sire model estimates. The expected herd life of pregnant cows was 420 d greater than for open cows. Each kilogram of increase in protein yield increased expected herd life by 9.5 d. Heritability of expected herd life increased from 0.11 for cows 6 mo after first calving to 0.14 for cows 3 yr from first calving. The genetic correlation of expected and actual herd life increased from 0.87 for records cut after 6 mo to 0.99 for records cut 3 yr after first calving. Phenotypic correlations increased from 0.61 to 0.94. Sire genetic evaluations based on predicted herd life of live cows were strongly biased if all records were weighted equally, and evaluations derived by weighting incomplete records to account for the effects of current herd life on variance components were nearly unbiased.     

烟草内生细菌种群特征分析

采用研磨组织稀释分离法分离不同品种、不同器官、不同生长期的烟草内生细菌,以各菌群出现与否为指标,用类平均法对数据进行系统聚类分析,对内生细菌的种类组成,分布特征进行了研究。结果表明,烟草内生细菌种类分布存在品种差异、生长期差异和组织部位差异;优势菌群的组成随分离组织部位和生长时期的不同而变化。Bacillus sp.和Rhizobium sp.是四个品种烟草叶片共有的优势类群,从苗期到团棵期,内生细菌的种类在增加,B. pumilus广泛存在于成熟期烟草根、茎、叶中,且为主要菌群。部分内生细菌具有组织偏好性,Micrococcus sp.和Staphylococcus sp.对烟草的茎部具有偏好性,B. cereus对烟草叶片具有偏好性。对烟草这一重要经济作物内生细菌的种类组成、分布特征进行研究,可为科学认知和利用这类微生物资源奠定基础。      

不同洗毛工艺对比分析

文章研究了非离子表面活性剂烷基糖苷APG作为洗涤剂和助剂在纺织行业的洗涤机理,探讨APG洗剂复配物组分、洗涤工艺条件、稳定性、生态指标等.利用烷基糖苷与其他洗剂复配后,采用不同洗毛工艺,运用正交设计方法进行实验,对不同洗毛工艺条件下洗净毛的断裂强度、白度以及含脂率进行性能测试,分析了不同洗毛工艺对洗净毛质量的影响,以获得具有性能和价格双重优势的APG及其复配洗剂,提出较好的非离子洗毛方案.     

我国不同产地赤霞珠挥发性香气成分差异分析

采用顶空固相微萃取结合气相色谱-质谱技术,对新疆石河子、宁夏青铜峡、山东烟台和河北怀来4个产地赤霞珠中47种香气成分进行定性定量分析。通过方差分析比较了不同产地赤霞珠香气成分特点。结果表明,反-2-庚烯醛、顺-2-戊烯-1-醇、苯酚、苯甲醇、辛酸、β-大马酮、己醛、反-2-己烯醛在不同产地赤霞珠葡萄中的含量具有显著性差异,新疆石河子产地赤霞珠风味物质特点是具有较高浓度的己醛和β-大马酮,宁夏青铜峡产地含有较低浓度的顺-2-戊烯-1-醇、己醛,山东烟台产地有较高浓度的反-2-己烯醛,而河北怀来产地有较高浓度的反-2-庚烯醛、辛酸。通过判别分析验证,方差分析得到的8种显著性差异成分可以100%地将赤霞珠样品按照产地正确分类。