烤后烟叶基因组DNA提取条件优化

为解决烤后烟叶基因组DNA提取稳定性差的问题,以烤后烟叶为材料,对CTAB法提取基因组DNA进一步改良优化:对CTAB沉淀缓冲液使用量、裂解时间、Tris平衡酚的处理次数和RNase处理时间4个影响因素进行单因素优化.实验结果表明:CTAB沉淀缓冲液使用DNA溶液体积的1.5倍、裂解时间40 min、Tris平衡酚抽提1次和RNase(10 mg/mL,1μL)处理10 min,能得到主带清晰的烤后烟叶基因组DNA.该方法提取得到的烤后烟叶基因组DNA OD260/OD280为1.7～1.9,OD260/OD230>2.0,35 ng左右基因组DNA即能得到清晰的RAPD和SCAR图谱,适用于以PCR为基础的分子生物学实验.     

野油菜黄单胞菌基因组DNA快速提取方法和酶切

本文建立了一种野油菜黄单胞菌(Xanthomonas campestris)基因组DNA的简便快速提取方法。用去污剂SDS和CTAB破坏细胞膜结构,使胞内核酸释放,用酚/氯仿/异戊醇去除蛋白质,经异丙醇沉淀DNA,TE溶解DNA。采用此SDS和CTAB结合的方法提取的DNA琼脂糖电泳图谱与试剂盒UNIQ-10提取的基因组DNA及D-5010A试剂盒法提取的基因组DNA图谱相同,DNA经紫外分光光度计检测OD260/OD280在1.80～1.90之间。DNA能被EcoRI、XbalI酶切消化。本方法能快速简便地提取野油菜黄单胞菌DNA,提取的DNA含量较高、纯度较好,比试剂盒更经济,也可用于酶切分析、构建文库和PCR扩增。     

不同破壁方法提取绍兴黄酒麦曲中的微生物总DNA

分别采用超声波、Yatalase酶法、氯化苄法对黄酒麦曲样品进行破壁,提取微生物总DNA,并通过细胞裂解率、DNA的纯度、片段的分布情况、ITS(内转录间隔区)序列扩增产物的多态性来评估不同的破壁方法对麦曲样品总DNA提取效果的影响。实验结果表明,采用氯化苄法能裂解86%的孢子,OD260/OD280在1.5左右,所得DNA片段分布在100bp～20kbI,TS-PCR扩增出的条带最多,而且简单、经济、提取效果好,可以作为麦曲中微生物总DNA的提取方法。     

豆奶粉基因组DNA不同提取方法的比较

以三种市售不同品牌的豆奶粉为材料,利用CTAB法和SDS法提取豆奶粉基因组DNA,探索从豆奶粉中获得高质量DNA的提取方法。结果表明:CTAB法提取的三种豆奶粉DNA的OD260/OD280值在2.01~2.05,因组DNA纯度较高,符合要求。琼脂糖凝胶电泳检测结果显示利用CTAB法获得的三种豆奶粉基因组DNA的电泳条带均清晰明亮,而且比SDS法获得的电泳条带更明亮,无弥散拖尾。因此,CTAB法是提取豆奶粉基因组DNA的更好更有效的办法,是理想的提取豆奶粉基因组DNA的一种方法,为进一步开展豆奶粉食物掺假、转基因成分测定奠定基础。     

苹果汁中DNA提取方法的比较及RAPD扩增研究

目的获得一种提取苹果汁饮料中高质量DNA的高效方法.方法以不同加工工制备的澄清苹果汁和果肉型苹果汁为试材,采用简易法、试剂盒法和改良试剂盒法提取苹果汁DNA,分别对所提取DNA的浓度、纯度及DNA扩增效率进行了比较.结果3种方法提取的澄清苹果汁DNA经PCR扩增后的条带均比果肉型苹果汁的清晰,其中,改良试剂盒法提取的澄清苹果汁DNA OD260/OD280的比值均在1.8左右,纯度最好.可用于RAPD扩增.结论试剂盒法和改良试剂盒法均适用于苹果汁饮料DNA的提取.其中试剂盒法对果肉型果汁的扩增效率较好,该方法为采用分子生物技术对果汁进行真伪鉴别提供技术参考.     

联苯胺预试验对血痕DNA-STR检验影响初探

目的:探究联苯胺预实验对血液DNA-STR检验的影响。方法:血痕分别经联苯胺法预实验、98%冰醋酸、联苯胺无水乙醇溶液、3%过氧化氢处理后,进行DNA提取、PCR反应、毛细管荧光电泳检测、DNA-STR分型分析。结果:经联苯胺预实验的血痕使用常规Chelex法提取DNA进行STR分析未获得完整的DNA图谱,但使用磁珠法提取DNA可获得完整良好的DNA图谱;经98%冰醋酸处理、1%联苯胺无水乙醇溶液分别处理的血痕使用常规Chelex法提取DNA进行STR分析均未获得完整的STR图谱,但使用改良Chelex法均可获得完整的STR图谱。结论:经联苯胺预实验处理的血痕不能使用常规Chelex法提取DNA进行STR检验。     

酿酒葡萄DNA的提取方法

采用琼脂糖凝胶电泳、核酸蛋白检测和聚合酶链反应扩增(polymerase chain reaction,PCR)检测DNA的浓度和纯度,对改良十六烷基三甲基溴化铵(hexadecyl trimethyl ammonium bromide,CTAB)法与2种商业试剂盒提取4种不同品种酿酒葡萄DNA的方法进行了对比分析,结果表明改良的CTAB法提取DNA完整性较好,基因组DNA样品的OD260/OD280值均在1. 8左右,4个酿酒葡萄均能扩增出PCR条带,且条带清晰,无拖尾现象。说明改良的CTAB法提取的酿酒葡萄基因组DNA浓度和纯度均较高,可以进行PCR扩增、电泳检测、遗传多样性分析以及基因图谱构建等下游分子生物学研究试验。     

简便易行的食用菌菌丝体基因组DNA提取法

用CTAB法直接从食用菌菌丝体培养物中提取DNA，并将所提取DNA进行PCR，得到了较清晰的扩增图谱，用该法提取的食用菌菌丝体DNA可用于分子生物学研究，具有简便易行的优点。     

CTAB法提取苏铁基因组DNA的条件优化

采用单因素梯度试验结合正交实验的方法（CTAB法）,优化了苏铁类植物全基因组DNA提取工艺.研究表明：材料量对提取DNA的浓度、提取率和纯度的影响最为明显,但还没有达到显著水平;最佳工艺参数为：20 mg苏铁羽片,65℃水浴处理30 min,抽提后,加入800 μL无水乙醇和5μL饱和NaCl溶液,6 000 r/min离心4 min沉淀DNA;溶解再沉淀后的DNA,质量浓度可达0.241 3 g/L,提取率可达0.483%,｜OD260/OD280-1.8｜＜0.01,可以满足RAPD-PCR分子标记技术应用.     

CTAB法提取苏铁基因组DNA的条件优化

采用单因素梯度试验结合正交实验的方法(CTAB法),优化了苏铁类植物全基因组DNA提取工艺.研究表明:材料量对提取DNA的浓度、提取率和纯度的影响最为明显,但还没有达到显著水平;最佳工艺参数为:20 mg苏铁羽片,65℃水浴处理30 min,抽提后,加入800 μL无水乙醇和5μL饱和NaCl溶液,6 000 r/min离心4 min沉淀DNA;溶解再沉淀后的DNA,质量浓度可达0.241 3 g/L,提取率可达0.483%,|OD260/OD280-1.8|＜0.01,可以满足RAPD-PCR分子标记技术应用.     

烟草靶斑病菌基因组DNA提取及RAPD反应体系的优化

采用改良的CTAB法,对16个烟草靶斑病菌菌株进行基因组DNA的提取,所得的DNA样品的OD26o/OD280值在1.76～1.89之间,电泳主带清晰,无弥散、拖尾现象,DNA质量较高.通过单因素和正交设计结合的方法对影响RAPD-PCR反应的主要因子Mg2+,dNTP,引物的浓度和模板DNA,Taq酶的用量进行了优化,建立了适宜于病菌的RAPD分子标记的最佳反应体系.优化的反应体系为:模板DNA 10 ng,Mg2+浓度3.25 mmol/L,dNTP浓度0.175 mmol/L,Taq酶1.4 U,引物浓度0.5 μmol/L,反应体系总体积为25 μL.通过该反应体系可以获得清晰、稳定、特异性的分子标记谱带,扩增结果较好.     

Physicochemical and Sensorial Properties of Grapefruit Jams as Affected by Processing

Jam is an effective and tasty way of preserving fruit. Jam processing procedures as well as storage conditions and duration are important factors for jam quality. Traditional jam processing involves the application of severe thermal treatments that imply undesirable changes in the product quality characteristics such as colour, texture, flavour and nutritional and functional value. In this work, osmotic dehydration (OD) and/or microwave energy (MW) was proven as adequate to obtain jam with the typical characteristics of water content, degree Brix, pH and water activity of jam obtained by conventional thermal heating. The sensory evaluation carried out to compare the product showed that samples submitted to more intense heating treatments (conventional or MW) had significantly higher scores in colour saturation, brightness, grapefruit taste and extensibility than OD or OD+MW ones. As deduced from the obtained results, OD treatment prevents grapefruit colour changes, and mild MW heating contributes to increase the consistency and decrease the extensibility of the obtained jam. In this way, OD+MW jam was preferred by assessors mainly due to its higher consistency. The sample obtained by this procedure was stable during storage.     

玉米包衣对种子鉴定过程中PCR扩增的影响

目的探讨玉米包衣内含有的杀虫剂、杀菌剂是否影响种子检测过程中的聚合酶链式反应(polymerase chain reaction,PCR)扩增效果及检测结果。方法利用紫外吸收法、凝胶电泳法以及PCR.扩增法对提取的包衣玉米DNA浓度和纯度进行测定,考察PCR扩增效果并对检测结果进行判定。结果不同清洗时间所提取的包衣玉米DNA与未包衣种子提取的DNA质量相比几乎没有差异,浓度和纯度均很好,DNA溶液OD_(260)/OD_(280)比值均在1.7~2.0之间,其DNA质量符合国家种子检测标准要求。玉米包衣对PCR扩增效果及检测结果没有影响。结论包衣玉米样品的种子进行检测时可不作清洗而直接进行DNA提取和PCR扩增,仍可得到准确可靠的结果,从而节约人力和物力并缩短检测时间。     

保温后熟及陈酿条件与玫瑰醋色泽形成的相关性研究

研究引入了色率、黄色指数、红色指数、玫瑰紫指数的概念,建立了对玫瑰醋色泽进行量化评价的方法。即将食醋稀释50％后,5000r／min离心30min,取上清液分别测其在波长460nm、510nm、530nm、610nm处的吸光度值,分别用10×lg（OD460nm／OD610nm）、10×lg（OD510nm／OD610nm）、10×lg（OD530nm／OD610nm）、OD610nm×20000／0．076来表示食醋的黄色指数、红色指数、玫瑰醋紫指数和色率,并用这种方法评价了保温后熟及保藏条件对食醋色泽的影响。通过试验发现在试验设计的保温时间范围内,色率随保温时间的增加呈下降趋势;黄色指数、红色指数、玫瑰紫指数随着保温时间缓慢增大;常温保藏比4℃保藏样品的色率更高,而黄色指数、红色指数、玫瑰紫指数则是4℃保藏样品比常温保藏的高。     

平菇基因组DNA提取方法的研究

以实验室自行培育的平菇为实验材料,分别使用CTAB法、SDS-CTAB法以及高盐酶解法提取平菇基因组DNA,并通过紫外分光光度计、限制性酶切及PCR检测来衡量基因组质量。结果表明,使用CTAB法很难得到高质量的基因组DNA,OD260/280仅为1.5左右,而且伴有较多的杂质,电泳条带拖尾严重;使用EcoRI限制性酶对其进行酶切分析,效率较低,同时PCR检测不能得到有效扩增;而使用优化后的SDS-CTAB法及高盐酶解法提取平菇DNA,能够获得质量高、纯度好的基因组DNA,OD260/280基本保持在1.8～2.0之间,电泳条带较为清晰均一,使用EcoRI限制性酶对其进行酶切分析,酶切效果较好,并且DNA质量能够满足PCR检测的模板要求。说明SDS-CTAB法以及高盐酶解法提取的平菇DNA能够满足分子水平操作的要求,两者相比,前者成本较低,后者产率较高。     

实时荧光PCR检测鸭血中的动物源性成分

目的建立实时荧光PCR检测鸭血中鸭、猪、牛等动物源性成分的方法。方法对重庆市火锅店销售的鸭血进行采样检测。提取鸭血样品DNA,进行实时荧光PCR检测,确定循环阈值,分析样品中鸭、猪、牛源性成分。结果 DNA提取液OD_(260 nm)/OD_(280 nm)值为1.8～2.0,纯度较高; 8个市售鸭血样品中2个样品只检出猪源性成分, 1个样品同时检出鸭源性成分和猪源性成分,研究发现所采集的鸭血存在猪血掺假的可能。结论该方法快捷、可操作性强,适用于鸭血中动物源性成分的测定。     

Centrifugal osmotic dehydration and rehydration of carrot tissue pre-treated by pulsed electric field

This paper studies the centrifugal osmotic dehydration (OD), rehydration and texture of carrot tissue treated by pulsed electric field (PEF). The influence of centrifugal acceleration (0-5430g), salt addition (NaCl/sucrose solutions 0/65, 7/44 and 15/50% w/w), and temperature (20-40 °C) on the OD kinetics was investigated in the presence and absence of PEF (E=0.60 kV/cm, treatment duration t_PEF=0.05 s). The centrifugal OD of samples untreated and treated by PEF was compared with OD under stirring (250 tr/min).Centrifugal force, PEF and salt addition increase the amount of water removed during OD. However, the centrifugal force decreases the intake of solids by the product.The application of PEF enhances both water loss (WL) and solid gain (SG) during OD (under stirring or centrifugation), increases the rehydration capacity of carrot tissue, but somewhat decreases the firmness of rehydrated product.The combination of centrifugal field with PEF and salt addition can be advantageous for reducing the OD duration. The textural study shows that the product obtained with OD is less affected by thermal treatment than the directly dried product.     

PILOT PLANT FOR OSMOTIC DEHYDRATION OF FRUITS: DESIGN AND EVALUATION

This work proposes a pilot scale equipment for osmotic dehydration (OD) of apple cubes that consists of a novel agitation‐immersion device, a bag filter and a vacuum evaporator to conduct simultaneously the OD process, filtration and reconcentration of the osmotic solution (OS). The functional method analysis was used to design the pilot plant. Apple cubes (～1 cm³) were dehydrated using a 60 ° Brix sucrose syrup OS at 50C and a syrup/fruit ratio of 5. OD was conducted either with or without reconcentration of the OS. During the OD process particles of fruit were eliminated from the OS by filtration and the OS concentration was kept at 60 ° Brix by reconcentration in the evaporator. A comparison of the dehydration parameters of apple cubes obtained at pilot scale to those obtained at laboratory scale was done to evaluate the performance of the pilot equipment. The results show that the proposed set‐up can be suitable for commercial production of osmodehydrated fruits.     

Total RNA concentration as an index of microbial activity and oxygen supply in an oxidation ditch

Total RNA and chromosomal DNA concentrations at a municipal wastewater treatment plant with an oxidation ditch (OD) were monitored for 1.5 years using commercial extraction kits for DNA and RNA. No parameters correlated with the chromosomal DNA concentration. The total RNA concentration exhibited better correlation than the solids retention time and the mixed liquor suspended solids with the removal rate of total organic carbon, and can be regarded as an index of microbial activity. The total RNA concentration varied with a cycle of one year and increased at lower water temperatures in this OD. When diffusion theory was taken into account, it was found that the oxygen dissolution rate increased at lower temperature, and a small change in the oxygen dissolution rate caused a large variation in microbial activity and also affected nitrification and denitrification. The information was insufficient to clarify the various reaction relationships, but total RNA concentration will likely be useful as an index of microbial activity in actual wastewater treatment reactors.