影响RNA提取质量的因素分析

RNA提取技术已经成为分子生物学中一个基本技术.教学和有一定特殊要求的科学研究需要透彻了解影响RNA提取的详细因素.细节对RNA提取的质量至关重要.本文对CTAB法提取RNA的全过程中各种影响因子进行了分析:CTAB法可以被用于RNA的提取;在CTAB提取缓冲中的温育时间以及机械摇动力是影响所提RNA质量的两个主要因素...     

壳聚糖-亚铁离子络合物在卷烟滤嘴中的应用

[目的]研究壳聚糖-Fe^2＋络合物对烟气有害成分的吸附作用。[方法]采用相关标准规定的方法检测含壳聚糖-Fe^2＋络合物二复合滤嘴对烟气中总粒相物、焦油、烟碱、水分、CO、酚类、挥发性羰基化合物、HCN等化学物质的滤过作用。[结果]壳聚糖-Fe2＋络合物对卷烟中焦油、烟碱、CO、挥发性羰基化合物、酚类物质、NNK、苯并芘和NH3没有明显的吸附作用,对烟气水分、HCN和苯酚则有较强的吸附作用。[结论]壳聚糖-Fe2＋络合物可以作物卷烟滤嘴的减害添加剂。     

室外木结构用胶粘剂胶合制品抗剪切性能评价

分别利用酚醛树脂胶粘剂和间苯二酚胶粘剂,对落叶松、桦木、红松、杉木4种树种进行胶合,测定制品在经过干状试验、真空-压力试验和蒸煮-干燥-冰冻试验之后的剪切强度。试验结果表明,经过干状试验、真空-压力试验后,间苯二酚胶粘剂的总体性能较好;而经过蒸煮-干燥-冰冻试验后,酚醛树脂胶粘剂较好。     

预冷对黄冠梨贮藏品质和果皮褐变的影响

研究了贮前预冷对不套袋和套袋（外灰内黑、外黄内白双层纸袋）黄冠梨贮藏品质和果皮褐变的影响,结果表明：套袋黄冠梨果皮褐变明显重于不套袋果实,并以套外黄内白袋的果实褐变严重。预冷对黄冠梨可溶性固形物（TSS）没有显著影响,但加快硬度下降,在一定程度上延缓了可滴定酸含量下降,并减轻果皮褐变的发生率,特别是对减轻套外黄内白袋果褐变效果非常明显。相关分析表明,预冷主要通过影响不套袋果实果皮酚含量,套外灰内黑袋果实果皮POD活性和套外黄内白袋果实果皮PPO活性来调控果皮褐变的。     

梨外植体组培褐变的影响因子及预防措施

以鸭梨、黄金梨、阿巴特梨和杜梨为试材,对梨组培过程中影响外植体褐化的因素及防褐措施进行了研究。结果表明,品种、采样时期以及外植体内酚类物质含量等因素都显著地影响材料褐化率。抗褐剂试验表明,培养基中添加0.2g/L的聚乙烯吡咯烷酮(PVP)或100mg/L抗坏血酸(Vc),或将外植体在200mg/L抗坏血酸水溶液中浸泡30min后接入添加2g/L活性炭的培养基,均能显著抑制鸭梨褐化的发生。低温试验表明,鸭梨外植体经4℃低温处理6h后接种,或接入初期在4℃低温中培养12～24h,褐化程度明显减轻。     

一株苯酚降解菌的筛选、鉴定及其降解特性

本研究采用逐量分批驯化的方法,从造纸废水中分离得到一株能够以苯酚为唯一碳源生长的苯酚降解菌株F5-1。经形态观察、生理生化特性鉴定及16S rDNA序列分析,将该菌株鉴定为克雷伯菌（Klebsiella sp.）。该菌株能够在7h时完全降解初始浓度为100mg/L的苯酚,降解苯酚主要发生在生长对数期;在pH5.0～9.0,NaCl浓度0～80g/L,温度20～40℃范围内,菌株F5-1均可有效降解初始浓度为100～1200mg/L的苯酚;能够耐受的最大苯酚浓度为1500mg/L。本研究结果表明,F5-1菌株对处理环境条件复杂的含酚废水具有潜在的应用前景。     

Phenol oxidase, peroxidase and organic matter dynamics of soil

Extracellular enzymes mediate the degradation, transformation and mineralization of soil organic matter. The activity of cellulases, phosphatases and other hydrolases has received extensive study and in many cases stoichiometric relationships and responses to disturbances are well established. In contrast, phenol oxidase and peroxidase activities, which are often uncorrelated with hydrolase activities, have been measured in only a small subset of soil enzyme studies. These enzymes are expressed for a variety of purposes including ontogeny, defense and the acquisition of carbon and nitrogen. Through excretion or lysis, these enzymes enter the environment where their aggegrate activity mediates key ecosystem functions of lignin degradation, humification, carbon mineralization and dissolved organic carbon export. Phenol oxidases and peroxidases are less stable in the environment than extracellular hydrolases, especially when associated with organic particles. Activities are also affected, positively and negatively, by interaction with mineral surfaces. High spatiotemporal variation obscures their relationships with environmental variables and ecological process. Across ecosystems, phenol oxidase and peroxidase activities generally increase with soil pH, a finding not predicted from the pH optima of purified enzymes. Activities associated with plant litter and particulate organic matter often correlate with decomposition rates and potential activities generally increase with the lignin and secondary compound content of the material. At the ecosystem scale, nitrogen amendment alters the expression of phenol oxidase and peroxidase enzymes more broadly than culture studies imply and these responses correlate with positive and negative changes in litter decomposition rates and soil organic matter content. At the global scale, N amendment of basidiomycete-dominated soils of temperate and boreal forest ecoystems often leads to losses of oxidative enzyme activity, while activities in grassland soils dominated by glomeromycota and ascomycetes show little net response. Land use that leads to loss of soil organic matter tends to increase oxidative activities. Across ecosystems, soil organic matter content is not correlated with mean potential phenol oxidase and peroxidase activities. A multiple regression model that includes soil pH, mean annual temperature, mean annual precipitation and potential phenol oxidase activity accounts for 37% of the variation in soil organic matter (SOM) content across ecosystems (n = 63); a similar model for peroxidase activity describes 32% of SOM variance (n = 43). Analysis of residual variation suggest that suites of interacting factors create both positive and negative feedbacks on soil organic matter storage. Soils with high oxygen availability, pH and mineral activity tend to be substrate limited: high in situ oxidative activities limit soil organic matter accumulation. Soils with opposing characteristics are activity limited: low in situ oxidative activities promote soil organic matter storage.     

电氧化阳极液中苯酚的测定

[目的]对电氧化降解含苯酚废水过程中苯酚的降解效率进行快速和精确的测定。[方法]选用4～氨基安替比林直接分光光度法测定模拟苯酚废水电氧化阳极液中苯酚的含量,研究试液起始pH值和支持电解质硫酸钠对测定结果的影响。[结果]当试液起始pH值在5．72～7．02,测定液中硫酸钠的浓度小于14．2g/L时,对苯酚的测定结果无影响。阳极电解液中的加标平均回收率98．6％～102．6％．说明测定方法可行。在实际测定过程中,可以通过调节试样的起始pH值和适当稀释试样来消除试样酸度和所含硫酸钠对测定结果的影响。[结论]4．氨基安替比林直接分光光度法适用于电氧化降解过程中苯酚含量的测定,且测定快速、灵敏,试验结果稳定、可靠,能够满足生产常规分析的精度和要求。     

酚/氯仿抽提法提取绵羊凝血块中基因组DNA

［目的］对组织DNA提取方法进行改进,建立一种从绵羊凝血块中提取基因组DNA的方法。［方法］将绵羊凝血块用眼科剪剪碎,用组织DNA抽提液裂解细胞,用蛋白酶K消化后,经过酚/氯仿抽提,无水乙醇沉淀获得基因组DNA。［结果］提取的DNA浓度为（159.90±0.70）ng/μl,A260/A280比值为1.80±0.01,分子完整,结果理想。以从凝血块中提取的DNA为模板,对绵羊BM203微卫星位点进行了PCR扩增,扩增效果良好。［结论］该方法简单、实用,提取的DNA可满足后续相关研究对DNA质量的要求,值得推广借鉴。     

酚／氯仿抽提法提取绵羊凝血块中基因组DNA

[目的]对组织DNA提取方法进行改进,建立一种从绵羊凝血块中提取基因组DNA的方法。[方法]将绵羊凝血块用眼科剪剪碎,用组织DNA抽提液裂解细胞,用蛋白酶K消化后,经过酚／氯仿抽提,无水乙醇沉淀获得基因组DNA。用NanoDropND-1000微型分光光度计检测DNA浓度和纯度。用0．8％琼脂糖凝胶电泳检验基因组DNA的完整性。以绵羊微卫星位点BM203为扩增位点,分别以F：5’-GG（汀G11：AcAmGTTCCC-3’,R：5’-CTGCTCCCCACTACTCCTTC-3’为上下游引物,进行PCR扩增试验。PCR产物用1．5％琼脂糖凝胶电泳检测．[结果]提取的DNA浓度为（159．90±0．70）ng／μl,A260／A280比值为1．80±0．01,分子完整,结果理想。以从凝血块中提取的DNA为模板,对绵羊BM203微卫星位点进行了PCR扩增,扩增产物条带整齐、明亮、特导性强,扩增效果好。[结论]该方法简单、实用,提取的DNA可满足后续相关研究对DNA质量的要求,值得推广借鉴。