不同提取方法对软枣猕猴桃多糖单糖组成及抗氧化活性的影响

采用高温水提工艺、低温水提工艺和微波辅助工艺从软枣猕猴桃中提取得到三种多糖,依次命名为AAP-1、AAP-2和AAP-3,对三种多糖的理化性质、单糖组成和抗氧化活性进行了研究.理化性质鉴定结果表明:三种多糖均不含酚羟基及还原糖,都含有一定量的糖醛酸和蛋白质,AAP-1含有淀粉,AAP-2和AAP-3不含淀粉;单糖组成结果表明:三种多糖均由甘露糖、鼠李糖、葡萄糖醛酸、半乳糖醛酸、葡萄糖、半乳糖、阿拉伯糖7种单糖组成,其中,AAP-1葡萄糖的摩尔百分含量最高,为94.72％;AAP-2半乳糖和阿拉伯糖的摩尔百分含量较高,分别为24.75％、38.37％;AAP-3半乳糖醛酸的摩尔百分含量较高,为16.05％.抗氧化实验结果表明:AAP-1抗氧化活性最弱;AAP-3抗氧化活性最强,其清除DPPH自由基和羟基自由基的IC50分别为1.2、2.7 mg/mL.     

The Effect of Sampling and Storage on the Fecal Microbiota Composition in Healthy and Diseased Subjects

Large-scale cohort studies are currently being designed to investigate the human microbiome in health and disease. Adequate sampling strategies are required to limit bias due to shifts in microbial communities during sampling and storage. Therefore, we examined the impact of different sampling and storage conditions on the stability of fecal microbial communities in healthy and diseased subjects. Fecal samples from 10 healthy controls, 10 irritable bowel syndrome and 8 inflammatory bowel disease patients were collected on site, aliquoted immediately after defecation and stored at -80°C, -20°C for 1 week, at +4°C or room temperature for 24 hours. Fecal transport swabs (FecalSwab, Copan) were collected and stored for 48-72 hours at room temperature. We used pyrosequencing of the 16S gene to investigate the stability of microbial communities. Alpha diversity did not differ between all storage methods and -80°C, except for the fecal swabs. UPGMA clustering and principal coordinate analysis showed significant clustering by test subject (p<0.001) but not by storage method. Bray-Curtis dissimilarity and (un)weighted UniFrac showed a significant higher distance between fecal swabs and -80°C versus the other methods and -80°C samples (p<0.009). The relative abundance of Ruminococcus and Enterobacteriaceae did not differ between the storage methods versus -80°C, but was higher in fecal swabs (p<0.05). Storage up to 24 hours (at +4°C or room temperature) or freezing at -20°C did not significantly alter the fecal microbial community structure compared to direct freezing of samples from healthy subjects and patients with gastrointestinal disorders.     

Quantifying Change Through Time in Spider Assemblages: Sampling Methods, Indices and Sources of Error

Using a sample dataset from six sites in the Southern Appalachian mountains in the United States, I evaluate the usefulness of diversity indices and similarity/difference indices for monitoring the changes in spider (Order Araneae) assemblages through time. The Shannon index, Brillouin index, Simpson's index and Margalef's index were correlated with each other and were able to detect successional changes in two old clear-cuts as well as disturbance to a Beech gap forest possibly due to Beech Bark Disease. Turnover, Bray-Curtis similarity, and Morisita-Horn similarity also detected successional differences between the forest types and indicated the short-term and long-term changes in a mature forest stand. Seasonal changes (early to late summer) in spider communities were consistently higher than yearly changes. I identify and discuss the implications of various sources of error that will adversely affect the accuracy and efficiency of a monitoring protocol: sensitivity of indices to sample size, sampler bias, inclusion of juveniles, taxonomic uncertainty and stochastic sampling effects. Although gross trends are still apparent in the sample data regardless of these errors, more subtle changes may be obscured. It is these subtle trends which may be more useful to managers attempting to identify disturbance before irreversible damage occurs.     

三种提取苹果绵蚜基因组DNA方法的比较

参考国内外昆虫基因组DNA提取的常用方法,选取KAc法、氯仿-异戊醇法和盐析法3种方法对苹果绵蚜(Eriosoma lanigerum)基因组DNA进行提取.通过基因组DNA直接琼脂糖凝胶电泳、SSR引物扩增产物的琼脂糖凝胶电泳和聚丙烯酰胺凝胶电泳检测,对3种方法所提基因组DNA的质量进行了比较,并综合分析了提取所需时间及所用试剂的毒性大小等.结果表明,盐析法操作程序较简便快捷,节时省工,可得较好质量的DNA样本,且对试验操作人员无伤害,是一种值得推广应用的基因组DNA提取方法.     

野生刺梨与甜橙苹果南瓜复合清汁的研制

本文对野生刺梨与甜橙、苹果和南瓜为原料加工而成的复合澄清汁 (饮料 )工艺及其产品质量控制进行了研究 ,所研制的产品达到了预期目标。本工艺对野生刺梨的进一步开发利用有一定促进作用     

Effect of Dwarfing Interstocks on Xylem Sap Composition in Apple Trees: Effect on Nitrogen, Potassium, Phosphorus, Calcium and Magnesium Content

This paper concerns nutrient concentrations in xylem sap collectedfrom above and below M.8, M.9, M.26 and M.7 dwarfing interstocks.The sap flowing from above an interstock had lower concentrationsof nutrients than that from the rootstock levels and these differencesincreased with the dwarfing effect of the interstock. There were indications that nutrient concentrations were enhancedbelow interstocks but were reduced in the sap flowing from theinterstocks into the scions. Generally these reductions weregreater the more dwarfing the effect of the interstock. Analyses of sap from above, mid-way along and below interstocksindicated that the changes in content were produced in, or closeto, the graft union between scion and interstock.     

The Occurrence and Survival of Coliforms and Salmonellas in Apple Juice and Cider

Apples and juices from large and small cidermakers were examined for the presence of coliform organisms and salmonellas. Coliforms were found both on the fruit and in the juice, and salmonellas were isolated on more than one occasion from the flume water. Experiments showed that salmonellas could survive in apple juice for 30 d at a pH of 3·6.     

Studies in the Nutrition of Apple Rootstocks The Effect on Growth and Mineral Composition of Supplying Iron Through the Leaves

Apple rootstocks were grown with either 0.02 ppm Fe (Fe₀) or5 ppm (Fe₃), to give very chlorotic or dark-green plants. Toinvestigate whether iron can be supplied through leaves insteadof roots the shoots of half the plants in each treatment weredipped periodically in solutions of iron. This prevented chlorosisin Fe₀ plants and increased their growth, which did not, however,equal that of Fe₃ plants supplied with iron through the roots.Growth of Fe₃ plants was reduced by dipping. Iron was not translocated from leaves to roots, although theconcentration in leaves was greatly increased by dipping. Dippingreduced the amount of manganese in Fe₀ roots to one-quarterof that in roots of undipped Fe₀ plants. Effects of treatmentson nitrogen, potassium, calcium, magnesium, and copper levelsare also described.     

Xylem Sap Composition in Apple Trees: Effect of the graft union

This paper records studies on the xylem sap from above and belowthe graft unions of apple trees with M·9, M·7and MM.104 rootstocks. The dry weight of solutes in sap fromabove the unions of the M·9 trees was between 30 and50 per cent lower than in sap from below, while the volume ofsap exuded was not reduced. The graft unions of the M·7and MM·104 trees had no significant effect on the xylemsap. These results are discussed in relation to the dwarfing effectsof rootstocks and interstocks.     

筛选差别表达基因的方法及其应用新进展

筛选差别表达基因是进行生物个体生长、发育调控和病理等研究工作的关键步骤之一,对基因组学、蛋白质组学以及更深层次的生命科学研究都具有重要意义。目前,筛选差别表达基因常用的方法主要有DDRT-PCR、SSH、SAGE和基因芯片等方法。本文就这些方法最新的应用进展进行了综述,并重点介绍了近年问世的Megaclone、Megasort和MPSS等新方法。     

筛选差异表达基因和蛋白质的方法进展

分离和鉴定差异表达基因和蛋白质不仅有助于发现基因和蛋白质的功能,更有助于揭示某些疾病的发生机理.目前筛选差异表达基因的方法主要有差异显示PCR方法(differential display RT-PCR,DDRT-PCR)、消减杂交法(subtractive hybridization,SH)、基因芯片技术(DNA chip technique)和基因表达的系统分析(serial analysis of gene expression,SAGE)等,其中消减杂交法中又先后建立了代表性差异分析技术(representational difference analysis,RDA)、抑制消减杂交法(suppression subtractive hybridization,SSH)和获得全长基因的消减杂交法(full-length-gene-obtainable subtractive hybridization).筛选差异表达蛋白质的方法主要有双向电泳技术(two-dimentional gel electrophoresis)和噬菌体全套抗体库技术(phage display antibody repertoire library technique).这些方法各有特点,各有利弊,研究者可根据自己的需要选择适合于自己的方法.     

Effect of Different Extraction Methods on Osmanthus Oil Quality

用超临界流体萃取法(SCFE)、可食用石油醚和酒精抽提蒸馏三种不同的抽提方法,提取了咸宁桂花品种——银星的花精油;气质联用(GC-MS)分析不同方法提取精油的香气成分及其相对含量.结果表明:SCFE提取的精油得率最高(0.19％),紫罗兰酮、醇类的相对含量高达36.99％;石油醚浸提结果次之(0.13％),酒精抽提法不可取(0.07％).     

不同提取方法对桂花精油品质的影响

用超临界流体萃取法(SCFE)、可食用石油醚和酒精抽提蒸馏三种不同的抽提方法,提取了咸宁桂花品种——银星的花精油;气质联用(GC-MS)分析不同方法提取精油的香气成分及其相对含量。结果表明:SCFE提取的精油得率最高(0.19%),紫罗兰酮、醇类的相对含量高达36.99%;石油醚浸提结果次之(0.13%),酒精抽提法不可取(0.07%)。     

中国大鲵非损害性DNA取样及提取方法的比较研究

基于DNA 分子的研究方法在物种分类及系统学、生态遗传学、保护生物学等领域中被广泛运用,但针对动物DNA取样方法的比较研究整体上较为缺乏。动物DNA取样要在对实验对象造成最小化影响和获得满足研究需要的DNA之间保持平衡,这需要不断探索取样方法的优缺点和适用性。本研究以人工繁育的水生有尾两栖动物中国大鲵（Andrias davidianus）为研究对象,比较口腔拭子、皮肤拭子、皮肤脱落物和尾静脉采血4种取样方式对DNA质量的影响。另外,基于其中皮肤拭子样品,进一步比较试剂盒法、高盐法、苯酚氯仿法和磁珠法对DNA提取效果的影响。结果表明,4种非损害性取样方法均能获取目标物种的DNA,且均未对取样对象的行为或适合度产生明显影响,但在DNA质量和浓度方面存在一定差异,其中,相对最好的为尾静脉采血,其次是口腔拭子和皮肤拭子,最差的为皮肤脱落物样品。而基于皮肤拭子样品采用4种不同DNA提取方法所获得的DNA效果整体差异不大。本研究通过以中国大鲵作为水生和非皮毛类动物的代表类群,研究并总结了不同DNA取样方法和提取方式的优缺点和注意事项,可为未来中国大鲵或其他珍稀濒危动物的非损害性取样方法及相关分子生态学研究提供借鉴。     

Studies of Different Sampling Methods for the Determination of Bacterial Counts from Frozen Broilers

The attachment of bacteria to the skin of broilers was not influenced by freezing or thawing of the carcasses. Only a small proportion of indicator organisms which were attached to the skin during processing were recovered in either the thaw water or rinsing fluid; a close correlation was found between bacterial counts from both types of sample. Numbers of Enterobacteriaceae and total counts were readily obtained by sampling the thaw water and this is, moreover, a non-destructive method. In order to detect the presence or absence of pathogenic micro-organisms the rinsing method was considered to be preferable, provided that the whole of the rinsing fluid was tested in each case.     

差异表达基因分离技术的研究进展

分离并克隆差异表达基因是生命科学的研究热点.近年来,以差示筛选、扣除杂交等基本方法为基础,先后出现了抑制差减杂交,微阵列技术等多种分析差异表达基因的技术, 使差异表达基因分离方法不断完善.对这些方法的优缺点、发展趋势及应用前景进行了简要综述.