分子生物学实验 Experiments of molecular biology. 一、 教学目的 《 分子生物学实验 》 课程主要从提取和分析遗传物质和基因为基础,从 DNA 的分离、纯化、克隆到目的基因的鉴定、表达等过程设计了一系列基础实验,形成一个涵盖现代分子生物学基础实验内容的实验课程教学体系,包括现代分子生物学基本技术方法,帮助学生巩固有关分子生物学的相关理论知识,并较系统地学习和掌握分子生物学的基本实验方法、技术和操作技能。 二、 教学要求 通过学习使学生对所有实验内容有一个整体的了解; - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
分子生物学实验分子生物学实验Experiments of molecular biology Experiments of molecular biology
1. Pick single colony and inoculate 5 ml of LB broth containing 200 g/l Ampicillin or 1mg/5ml with a loosened cap and a piece of tape to hold it in place. Shake at 250 RPM 37oC overnight.
2. Centrifuge 1.5mL cells in 1.5 mL Eppendorf tube at top speed for 1 minute. Discard supernatant.
3. Resuspend cell pellet in 100 ul of GTE buffer (50 mM Glucose, 25 mM Tris-Cl, 10 mM EDTA, pH 8). Vortex gently if necessary.
4. Add 100 ul of NaOH and SDS lysis solution (0.2 M NaOH, 1% SDS) respectively. Invert tube 6-8 times.
5. IMMEDIATELY add 150 ul of 5 M potassium acetate solution (pH 4.8). This solution neutralizes NaOH in the previous lysis step while precipitating the genomic DNA and SDS in an insoluble white precipitate. Spin at top speed 1 min.
6. Transfer supernatant to new tube, being careful not to pick up 6. Transfer supernatant to new tube, being careful not to pick up any white flakes. Precipitate the nucleic acids with 0.5mL of iany white flakes. Precipitate the nucleic acids with 0.5mL of isopropanol on ice for 10 minutes and centrifuge at top speed fsopropanol on ice for 10 minutes and centrifuge at top speed for 1 minute.or 1 minute.
7. Aspirate off all the isopropanol supernatant. Dissolve the pellet 7. Aspirate off all the isopropanol supernatant. Dissolve the pellet in 0.4 ml of in 0.4 ml of TE bufferTE buffer (10 mM Tris-Cl, 1 mM EDTA, pH 7.5). (10 mM Tris-Cl, 1 mM EDTA, pH 7.5). Add 10ul of RNAse A solution (20 mg/ml stock stored at -20 °Add 10ul of RNAse A solution (20 mg/ml stock stored at -20 °C), vortex and incubate at 37 °C for 20 to 30 minutes to digest C), vortex and incubate at 37 °C for 20 to 30 minutes to digest remaining RNA. remaining RNA.
8. Extract proteins from the plasmid DNA using phenol/chlorofor8. Extract proteins from the plasmid DNA using phenol/chloroform/ isoamyl alcohol (PCIA) by adding about 0.4 ml. Vortex vigm/ isoamyl alcohol (PCIA) by adding about 0.4 ml. Vortex vigorously for 30 seconds. Centrifuge at full speed for 5 minutes orously for 30 seconds. Centrifuge at full speed for 5 minutes at room temperature. Note organic PCIA layer will be at the bat room temperature. Note organic PCIA layer will be at the bottom of the tube. ottom of the tube.
9. Remove upper aqueous layer containing the plasmid DNA care9. Remove upper aqueous layer containing the plasmid DNA carefully avoiding the white precipitated protein layer above the Pfully avoiding the white precipitated protein layer above the PCIA layer, transferring to a clean 1.5 ml eppendorf tube. CIA layer, transferring to a clean 1.5 ml eppendorf tube.
10. Repeat 9 step again.10. Repeat 9 step again.11. Add 1 ml of absolute ethanol to precipitate the plasmid DNA 11. Add 1 ml of absolute ethanol to precipitate the plasmid DNA
and 50 ml of 3 M Sodiun acetate solution on ice for 10 minuteand 50 ml of 3 M Sodiun acetate solution on ice for 10 minutes. Centrifuge at full speed for 5 minutes at room temperature. s. Centrifuge at full speed for 5 minutes at room temperature.
12. Discard ethanol solution and resuspend DNA pellet in 50ul of 12. Discard ethanol solution and resuspend DNA pellet in 50ul of TE buffer. TE buffer.
13. Dissolve 5uL in 995ul of water, and spec (blank spectrophoto13. Dissolve 5uL in 995ul of water, and spec (blank spectrophotometer to water). The absorbance at 260 nm multiplied by ten is meter to water). The absorbance at 260 nm multiplied by ten is the concentration of the DNA in units of mg/ml for a 1 cm patthe concentration of the DNA in units of mg/ml for a 1 cm pathlength cuvette (i.e. 50 mg/ml/OD 260nm). hlength cuvette (i.e. 50 mg/ml/OD 260nm).
Solution D can be made and stored at 4°C without b-mercaptoetSolution D can be made and stored at 4°C without b-mercaptoethanol for several months. b-mercaptoethanol should be added thanol for several months. b-mercaptoethanol should be added to 100mM immediately prior to use. b-mercaptoethanol is used to o 100mM immediately prior to use. b-mercaptoethanol is used to prevent the reformation of the intra-molecular disulphide bridges prevent the reformation of the intra-molecular disulphide bridges , one of the reasons for the extreme stability of ribonucleases. , one of the reasons for the extreme stability of ribonucleases.
1) Tissue is homogenized as rapidly as possible, at 4°C, in solution D (500ul per 50mg tissue) with an eppendorf pestle hom1) Tissue is homogenized as rapidly as possible, at 4°C, in solution D (500ul per 50mg tissue) with an eppendorf pestle homogenizer until a smooth, lysed, homogenous suspension is obtained. ogenizer until a smooth, lysed, homogenous suspension is obtained.
2) Add 50ul 2M sodium acetate, pH4.0 and mix vigorously. 2) Add 50ul 2M sodium acetate, pH4.0 and mix vigorously. 3) Add 500ul phenol and mix vigorously. 3) Add 500ul phenol and mix vigorously. 4) Add 100ul chloroform, mix vigorously and incubate on ice for 15 minutes. 4) Add 100ul chloroform, mix vigorously and incubate on ice for 15 minutes. 5) Centrifuge mixture at 10,000g for 10 minutes in a microfuge at 4°C. 5) Centrifuge mixture at 10,000g for 10 minutes in a microfuge at 4°C. 6) Remove upper, aqueous phase to a clean, sterile, DEPC-treated eppendorf tube. After centrifugation, RNA is present in t6) Remove upper, aqueous phase to a clean, sterile, DEPC-treated eppendorf tube. After centrifugation, RNA is present in t
he aqueous phase while, due to protonation at the acidic pH used, genomic DNA is partitioned into the phenol phase. he aqueous phase while, due to protonation at the acidic pH used, genomic DNA is partitioned into the phenol phase. 7) Extract the upper aqueous layer with an equal volume phenol/chloroform and centrifuge as before. Repeat the extraction7) Extract the upper aqueous layer with an equal volume phenol/chloroform and centrifuge as before. Repeat the extraction
s until no interface material is seen. s until no interface material is seen. 8) Precipitate the aqueous phase by the addition of an equal volume (500ul) of propan-2-ol. Incubate at -20°C for 20 minute8) Precipitate the aqueous phase by the addition of an equal volume (500ul) of propan-2-ol. Incubate at -20°C for 20 minute
s. s. 9) Pellet RNA by centrifugation at maximum speed in a microfuge for 10 minutes. 9) Pellet RNA by centrifugation at maximum speed in a microfuge for 10 minutes. 10) Wash the RNA once in 70% ethanol and vacuum dry. 10) Wash the RNA once in 70% ethanol and vacuum dry. 11) Re-dissolve in 200ul 0.5% SDS at 65°C. 11) Re-dissolve in 200ul 0.5% SDS at 65°C. 12) Extract with an equal volume (200ul) of phenol/chloroform as above. Repeat until no interface material is visible. 12) Extract with an equal volume (200ul) of phenol/chloroform as above. Repeat until no interface material is visible. 13) Precipitate pure RNA by the addition of 20ul 3M sodium acetate, 100mM acetate, pH 5.2 and 500ul absolute ethanol. In13) Precipitate pure RNA by the addition of 20ul 3M sodium acetate, 100mM acetate, pH 5.2 and 500ul absolute ethanol. In
cubate at -20°C for 20 minutes. cubate at -20°C for 20 minutes. 14) Pellet RNA by centrifugation at maximum speed in a microfuge for 10 minutes. 14) Pellet RNA by centrifugation at maximum speed in a microfuge for 10 minutes. 15) Wash the RNA once in 70% ethanol and vacuum dry. 15) Wash the RNA once in 70% ethanol and vacuum dry. 16) Dissolve RNA in appropriate buffer i.e. DEPC-treated, sterile TE, pH 8 or 0.5% SDS if no enzymic manipulation of the R16) Dissolve RNA in appropriate buffer i.e. DEPC-treated, sterile TE, pH 8 or 0.5% SDS if no enzymic manipulation of the R
NA is needed. SDS is an inhibitor of ribonucleases. NA is needed. SDS is an inhibitor of ribonucleases. RNA quality can be assessed by electrophoresis under denaturing conditions using agarose/formaldehyde gels and the MORNA quality can be assessed by electrophoresis under denaturing conditions using agarose/formaldehyde gels and the MO