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---
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föreläsare: Oliver Forsell
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tags:
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- biokemi
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- anteckningar
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- rekombinant-dna-teknik
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---
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Rekombinant DNA-teknik
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Steg
|
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- Molekylär kloning
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- använder sig av en DNA snutt, en reflektionsenzym
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- foga in det i en slags vektor, ofta i en plasmid
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- Samma plasmid har förmåga klippa iihop samma baspar
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- foga ihop sin DNA
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- med hjälp av vegasenzym
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- Transformationen
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- För in den här vektor i en värd-cell
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- Selektera och replikera
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- Växa den i fermentortankar, så man får tillräckligt mycket av sitt material
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#### Plasmider
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Dubbelsträngat ciruklärt DNA, finns i de flesta bakterier.
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Självreplikera vid celldelning och gemensama gener
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t.ex. anti-biotikaresistens som bakterierna kan dela med sig
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kraftfullt verktyg som vi har lyckats att kapa
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Hur kan vi använda oss av det här?
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### Applications
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- Biomedicinska lösningar, t.ex. vaccin Hepatit-B
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- Framställer ett ytprotein på bakterien, istället för att injecra ett helt virus, det räcker med själva proteinet för att starta immunförsvaret istället för en riktig virus
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- Produktion av insulin
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- jästceller istället för bakterier
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- post-transationella modifieringar
|
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- de är eukaryota celler, så det krävs för insulin
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- Koaguleringsfaktor-8
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GMO
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- Använder man av rekombinant DNA-teknik för att skapa,
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- t.ex. resistens mot en herbicid
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Genterapi
|
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- CRISPR/Cas9 framställer man på det sättet
|
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- Kan ersätta delar av vårat DNA
|
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- behöver en vektor, för att transportera in
|
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- Adeno-virus är en vanlig vektor, som man producera rekombinant
|
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Genanalys
|
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- polymeraser, Polymerace-Chain-Reaction.
|
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- en teknik för att detektera närvaron av ett viss protein
|
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- de kan kopiera en molekyl många gånger
|
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- specifika temperaturer med hjälp av rekombinant
|
||||
|
||||
|
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### Verktyg som behövs
|
||||
- "saxar", som kan bryta ner
|
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- "capping site" en plats i plasmiden där själva urklippandet kan ske
|
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- en sekvens med baspar som enzymet känner igen
|
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- "limmet", dna-ligaser så det går att foga fast
|
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- värd-cell, ofta bakterieceller
|
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- rätt miljö, LP-medium ett slags näringsmedel som bakterier trivs i
|
||||
- ska göra massa olika kopier, ofta proteiner av det
|
||||
|
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### Vektorer
|
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Själva plasmiden, en slags molekyl som kan transportera DNA som vi är intresserad av
|
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En viktig del är
|
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- Ori - origin of replication
|
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- massa olika baspar, som olika restriktionsmolekyler kan känna igen
|
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- AmpR: kan producera β-laktamas, den förhindra verkan av ampicilin
|
||||
- Promotor krävs för att pol ska kunna binda och uttrycka en gen
|
||||
- LacZ alpha: poängen
|
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- när vi inte fogat in våran gen är LacZ kontakt
|
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- om vi för in den, bryter vi upp LacZ, för det vi klipper är i mitten av det
|
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- om man inte fört in kommer LacZ kommer binda till alpha-peptiden i β-kalaktas
|
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- Muterad E Coli-stammen så den har inte i sitt vanliga DNA den här alpha-peptiden, bara delta-delen,
|
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- för att e coli ska kunna producera en b-kalaktas
|
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- IPTG inaktivar repressor genet
|
||||
- om vi tillsätter IPTG så kommer det vara fritt fram att uttrycka alpha-
|
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|
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### Restriktionenzymer
|
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- BamH I
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- GGATC
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- Generera strick enzo
|
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- klipper snett för att det är lättare att sammanfoga sen
|
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|
||||
### Värd-cell: E. Coli
|
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Vanligt modellorganism
|
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Gram negativ
|
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- den färgas rosa (positiva lila) med graminfärgning
|
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- de har tunt membranvägg
|
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- grovt dela upp bakterierar i de som har/inte har de yttre höljet
|
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Finns naturligt i tjocktermen
|
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||||
|
||||
### Insulin
|
||||
Började produceras 1920-talet
|
||||
Krävdes upp till 70 grisar för att hålla en person levande i ett år utan rekombinant DNA-teknik
|
||||
Utvann från bukspottskörteln, 1g på 70 grisar
|
||||
1970 utvecklades rekombinant DNA-teknik, kommerciellerades på 1980-talet
|
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|
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### Labsyfte
|
||||
Ska avgöra om våran gen av intresse har lyckats klona in i vektorn
|
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Fokus är inte gen, mer på själva processen
|
||||
t.ex. insulin
|
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## Transformation
|
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|
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Vi kommer använda oss av rekombinanta plasmider och kombinera de med e coli-celler
|
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Cellerna måste vara mottagliga för att ta upp plasmiden
|
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Calciumjoner neutraliserar den negativa ytan (fosfoliper och glykoliper), så att DNA kan närma sig ytan det är också negativt
|
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Sen höjer man med en värmsjuk, membranet blir permeabiliserat.
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|
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blue-white screening
|
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lacz kommer naturligt med e coli, mutantsträng som saknar alphadelen.
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|
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En analog till en galaktosias, den heter X-gal, när den bryts ner bildas galaktos, men den bildar också 4-chloro-3-bromo-indigo som gör att det blir blå, då kan vi se vilka bakteriera som har en intakt lacZ eller inte.
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|
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De som har våran gen av intresse blir inte färgade, de är svåra att se, men inte osynliga.
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|
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Western Blot kan man använda för att identifiera ett protein av intresse
|
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|
||||
|
||||
|
||||
|
||||
@@ -1,89 +0,0 @@
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---
|
||||
tags:
|
||||
- biokemi
|
||||
- rekombinant-dna-teknik
|
||||
- anteckningar
|
||||
föreläsare: Oliver Forsell
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date: 2025-11-26
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---
|
||||
Sätter dit en prime av intresse, restriktionssite. En insert som med hjälp av restriktionsenzym kan kapa och får en sticky ends.
|
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|
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self-ligated vector, plasmiden binder till sig själv, isolera med blue/white.
|
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ampicillin?
|
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x-gal?
|
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iptg? lacz-alpha restriction, sitter ett repressionprotein, iptg inaktiverar en repressor
|
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AmpR: ampicillin restistans
|
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pellet?
|
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supernatant: det som hamnar ovanpå
|
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nukleasfritt vatten
|
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kilator? ko-faktor för vatten
|
||||
RnasaA: bryter ner RNA
|
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SDS löser upp fosfolipider och proteiner i cellmembranet
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eulera
|
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SYBR safe
|
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|
||||
---
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Dagens labb
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|
||||
# Rena fram plasmiden
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# Klippar ur genen av intresse
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# Kör agarose gel
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# Tolka resultatet
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||||
|
||||
----
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||||
|
||||
### What are the sites the plasmid contains that allow for this experiment?
|
||||
- Lacz
|
||||
- Β-lactamas (ampicilin resistansen)
|
||||
- BamH-insertion site, i vårta multiple cloning site
|
||||
- Origin of replication för att kunna replikera
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|
||||
#### What are the 3 compounds in the LB plates that allow for selection of bacteria with plasmid and the distinction of plasmids with and without the inserted gene?
|
||||
- IPTG
|
||||
- X-Gal
|
||||
- Ampicillin
|
||||
|
||||
### What are the six steps in plasmid preparation and purification?
|
||||
1. Pelleteringen
|
||||
2. **Suspendera**, lösa upp pelleten
|
||||
3. **Lysering** - så det läcker ut plasmid
|
||||
4. **Neutralisera** - skyddar plasmiden på nytt
|
||||
5. **Skölja bort salter**
|
||||
6. Tillsätta vatten för att eulera ut vår plasmid
|
||||
|
||||
|
||||
### What is a restriction enzyme and why was it used in this experiment?
|
||||
|
||||
Hjälpa till att klippa ut genen och foga in vår plasmid, sticky ends
|
||||
|
||||
|
||||
### Explain the principle of Gel Electrophoresis, what is it for?
|
||||
|
||||
Separation av storlek eller massa på våra DNA-fragment. Elektrostatiskt repulsion, som får våra joner att separeras
|
||||
|
||||
### What´s the compound that allows for the visualization of the DNA in the gel?
|
||||
|
||||
SYBR safe
|
||||
|
||||
### How many times does BamHI cut the plasmid without the insert? And the plasmid with the insert?
|
||||
|
||||
Hur många gånger kommer BamHI klippa vår plasmed
|
||||
- utan insert: 1
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||||
- med insert: 2 på var sin sida om inserten för att få ut den
|
||||
|
||||
### Explain the different plasmid conformations that exist.
|
||||
|
||||
- relaxed
|
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- supercoiled supper snabbt, de är tvinnade
|
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- linjära
|
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-
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Vektorer är DNA-molekyler (t.ex. plasmider) som har specifika klipp- och infogningsställen där man kan sätta in gener för kloning eller uttryck.
|
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|
||||
När man klipper DNA använder man restriktionsenzymer, som känner igen och klyver specifika sekvenser.
|
||||
|
||||
MCS (multiple cloning site) är en kort DNA-region i en vektor som innehåller många unika restriktionsställen där man kan klippa och sätta in gener.
|
||||
|
||||
Man ligerar DNA med DNA-ligas, ett enzym som kopplar ihop ändarna genom att skapa fosfodiesterbindningar.
|
||||
|
||||
BamH I är ett restriktionsenzym
|
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|
||||
Klyvning kan ge två typer av ändar: sticky ends (överhängande ändar) och blunt ends (trubbiga ändar).
|
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|
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E. coli används eftersom den växer snabbt, är lätt att odla och genetiskt manipulera, och vi känner dess genom mycket väl.
|
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|
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### Dag 1 & 2:
|
||||
- Genen lacZ i E. coli kodar för enzymet β-galaktosidas
|
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- IPTG är en inducer som behövs för att slå på lacZ, så att enzymet faktiskt bildas
|
||||
- X-gal är ett konstgjort substrat, som blir blått när de klyvs av β-galaktosidas
|
||||
- X-gal och 5-Bromo-4-Chloro-3-Indolyl β-D-Galactopyranoside är samma sak
|
||||
- Normalt klyver enzymet β-galaktosidas X-gal → blått färgämne bildas
|
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- För att substratet ska bli blått krävs lacZ, IPTG och X-gal. Saknas några av dem blir det inte blått
|
||||
- Ampicillin dödar bakterier som inte har plasmiden, så bara de vi vill studera överlever.
|
||||
- Heat-shock 0->37 grader skapar en tryckskillnad och öppnar porer i membrandet så plasmid-DNA kan ta sig in i cytoplasman
|
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- Nerkylning direkt efteråt gör att de stannar kvar
|
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- LB-plattan är både odlingsmedium och selektions-/screeningsverktyg
|
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- näring (aminosyror, mineral, salt, tillväxtfaktorer osv)
|
||||
- ampicillin dödar allt utan plasmid
|
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- IPTG slår på lacZ
|
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- X-gal infärgning
|
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|
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### Dag 3
|
||||
|
||||
#### A. Förbered plasmiden
|
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|
||||
Cellerna centrifugeras, spräcks och plasmiden separeras från cellskräpet. Plasmiden fångas sedan upp i en spin-kolonn, tvättas ren och sköljs ut i en ny tub.
|
||||
|
||||
![[Pasted image 20251128104012.png]]
|
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|
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Vi har två lösningar i separata falkonrör, en blå (utan våran insert) och en vit (med vår insert). Upprepa alla stegen för varje lösning.
|
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|
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| Steg | Input | Output | Kort beskrivning |
|
||||
| --------------- | -------------------- | -------------------------------------- | --------------------------------------------------------------- |
|
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| 1. Pelletera | Bakteriekultur | Cellpellet + borttagen supernatant | Celler centrifugeras ned till botten. |
|
||||
| 2. Lös upp | Cellpellet + A1 | Jämn cellsuspension | Löser upp pelleten så lysering kan fungera. |
|
||||
| 3. Lysera | Cellsuspension + A2 | Lyserad lösning | Cellmembran öppnas, plasmid + DNA/proteiner frigörs. |
|
||||
| 4. Neutralisera | Lyserad lösning + A3 | Fällt skräp + plasmid i lösn. | Stora DNA/proteiner klumpar ihop sig. Plasmiden stannar löslig. |
|
||||
| 5. Centrifugera | Neutraliserad mix | Pellet (skräp) + supernatant (plasmid) | Plasmiden separeras från cellskräp. |
|
||||
| 6. Ladda kolumn | Supernatant | Plasmid bundet till kolumn | Plasmiden fastnar på membranet; skräp rinner igenom. |
|
||||
| 7. Tvätta | Kolumn + A4 | Renad kolumn | Tar bort salter, proteiner och kvarvarande föroreningar. |
|
||||
| 8. Torka kolumn | Tvättad kolumn | Torr kolumn | Extra spinn för att avlägsna etanolrester. |
|
||||
| 9. Skölj | Kolumn + vatten | Ren plasmid-DNA i eppendorf | Vattnet löser av plasmiden från membranet. |
|
||||
Vi får nu ut en ren plasmid
|
||||
|
||||
#### B. klyv plasmiden med BamHI och jämför den med en oklippt kontroll.
|
||||
|
||||
Skapa en BamHI-enzym som kan klippa plasmiden, klipp plasmiden och tillsätt färgnings
|
||||
|
||||
Master solution:
|
||||
- vatten, buffert och enzym blandas in
|
||||
|
||||
Digested = cut = plasmid som har blivit klippt vid BamHI-sajten
|
||||
Cybr safe gör det synligt i UV-ljus utan att vara cancerframkallande
|
||||
loading dye gör att vi kan se vad vi pipeterar in i elektroforesen i nästa steg
|
||||
|
||||
![[Pasted image 20251128104645.png]]
|
||||
|
||||
|
||||
| Steg | Input | Output | Kort beskrivning |
|
||||
| ----------------------------- | ------------------------- | -------------------------------- | ---------------------------------------------------- |
|
||||
| 1. Gör BamHI-mastermix | H₂O + 10× buffer + BamHI | Färdig enzymmix | Blandar så alla prover får samma enzym och buffer. |
|
||||
| 2. Fördela plasmider | Plasmid-DNA | Tub “white-cut” + tub “blue-cut” | Flyttar plasmiderna till nya rör för klippning. |
|
||||
| 3. Tillsätt master + inkubera | Plasmid + BamHI-mastermix | Digesterat (klippt) DNA | Enzymet klipper plasmiden vid BamHI-sajten. |
|
||||
| 4. Tillsätt loading dye | Klippt DNA + dye | Färdiga “cut”-prover för gel | Gör proverna tyngre och synliga i gelen. |
|
||||
| 5. Gör oklippta kontroller | Plasmid + loading dye | “white-uncut” + “blue-uncut” | Referensprover som visar hur odigesterat DNA ser ut. |
|
||||
|
||||
Du blandar en BamHI-lösning, blandar den med plasmiderna och låter enzymet klippa DNA:t vid 37 °C. Sedan tillsätter du loading dye och gör även två oklippta kontroller för jämförelse i gelen.
|
||||
|
||||
|
||||
#### Steg 3
|
||||
|
||||
Elektrofoera och läs av i UV-ljus
|
||||
|
||||
![[Pasted image 20251128104949.png]]
|
||||
|
||||
| Steg | Input | Output | Kort beskrivning |
|
||||
| ---------------------------- | --------------------------- | -------------------------------- | --------------------------------------------- |
|
||||
| 7. Ladda prover | Marker + cut/uncut-prover | Gel med laddade prover | Proverna placeras i rätt ordning i brunnarna. |
|
||||
| 8. Kör elektrofores | Gel i tank + 120 V | Separering av DNA-fragment | DNA vandrar efter storlek genom gelen. |
|
||||
| 9. Fotografera | Färdigkörd gel | UV-bild med DNA-band | Bandmönstret visar plasmidens storlek/insätt. |
|
||||
@@ -1,24 +0,0 @@
|
||||
---
|
||||
tags:
|
||||
- biokemi
|
||||
- instuderingsuppgifter
|
||||
- plasmid
|
||||
---
|
||||
#### Name three applications of molecular cloning.
|
||||
#### What is a plasmid?
|
||||
#### Name the three main steps involved in recombinant DNA technology?
|
||||
#### What is a restriction enzyme?
|
||||
#### What are the bacteria used in your protocol?
|
||||
#### Explain the calcium/phosphate (heat-shock) method and what it is used for.
|
||||
#### How can we selectively grow bacteria that have taken up the plasmid?
|
||||
#### Explain the principle behind blue and white screening and its purpose in this lab.
|
||||
|
||||
#### What are the sites the plasmid contains that allow for this experiment?
|
||||
#### What are the 3 compounds in the LB plates that allow for selection of bacteria with plasmid and the distinction of plasmids with and without the inserted gene?
|
||||
#### What are the six steps in plasmid preparation and purification?
|
||||
#### What is a restriction enzyme and why was it used in this experiment?
|
||||
#### Explain the principle of Gel Electrophoresis, what is it for?
|
||||
#### What´s the compound that allows for the visualization of the DNA in the gel?
|
||||
#### How many times does BamHI cut the plasmid without the insert?
|
||||
#### And the plasmid with the insert?
|
||||
#### Explain the different plasmid conformations that exist. Förståelse Biokemi / Plasmidlabb /
|
||||
@@ -1,38 +0,0 @@
|
||||
|
||||
## Att göra
|
||||
- [ ] Samla ihop, infoga bilder
|
||||
- [ ] Skapa ordentliga referenser
|
||||
- [ ] Annotera resultat med korrekt storlek (rader) och namn på kolumner
|
||||
- [ ] Diskution: Svara på Olivers fråga angående vad som kan göras för att förbättra sannolikheten för att inte få in _vita_ ämnen i _blåa_ provet
|
||||
- [ ] Se till att komprimera texten, så allt viktigt får plats på 3 sidor
|
||||
## Referenser
|
||||
|
||||
- A rapid alkaline extraction procedure for screening recombinant plasmid DNA.
|
||||
- H.C. Birnboim, J. Doly
|
||||
- 1973
|
||||
- [10.1093/nar/7.6.1513](https://doi.org/10.1093/nar/7.6.1513)
|
||||
- Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of _Escherichia coli_ by R-Factor DNA
|
||||
- Stanley N. Cohen, Annie C. Y. Chang, and Leslie Hsu
|
||||
- 1972
|
||||
- 10.1073/pnas.69.8.2110
|
||||
- New versatile cloning and sequencing vectors based on bacteriophage M13
|
||||
- M P Kieny, R Lathe, J P Lecocq
|
||||
- 1983
|
||||
- 10.1016/0378-1119(83)90039-2
|
||||
- Restriction and modification enzymes and their recognition sequences
|
||||
- R J Roberts
|
||||
- 1985
|
||||
- 10.1093/nar/13.suppl.r165
|
||||
- Detection of two restriction endonuclease activities in Haemophilus parainfluenzae using analytical agarose--ethidium bromide electrophoresis
|
||||
- P A Sharp, B Sugden, J Sambrook
|
||||
- 1973
|
||||
- 10.1021/bi00740a018
|
||||
---
|
||||
**Jackson, Symons & Berg (1972)**
|
||||
|
||||
_Biochemical method for inserting new genetic information into DNA of Simian Virus 40: Circular SV40 DNA molecules containing lambda phage genes and the galactose operon of Escherichia coli._
|
||||
PNAS 1972.
|
||||
PMCID: PMC389671
|
||||
PMID: 4342968
|
||||
|
||||
→ Nobelpriset 1980 till Paul Berg
|
||||
@@ -1,187 +0,0 @@
|
||||
Recombinant DNA technology
|
||||
Lecture by:
|
||||
Anne Wöhr
|
||||
anne.wohr@gu.se
|
||||
|
||||
Molecular Cloning
|
||||
→ Performed beforehand (not done during this lab)
|
||||
|
||||
Molecular Cloning
|
||||
→ Performed beforehand (not done during this lab)
|
||||
We aim to isolate/separate
|
||||
these two plasmids to
|
||||
select the recombinant
|
||||
plasmid and to verify the
|
||||
presence of the gene of
|
||||
interest
|
||||
|
||||
Day 1: Transformation of competent cells
|
||||
→ performed during this lab (day 1)
|
||||
|
||||
Day 1: Selection of transformed cells
|
||||
→ performed during this lab (day 1 + day 2)
|
||||
|
||||
Day 2: Picking & expansion of blue
|
||||
and white colonies
|
||||
→ performed during this lab (day 2)
|
||||
|
||||
Revision
|
||||
Blue-white screening
|
||||
Plasmid:
|
||||
• AmpR: Ampicillin resistance (β-lactamase)
|
||||
• LacZ: α-peptide for functional β-galactosidase
|
||||
enzyme
|
||||
• BamHI restriction site in LacZ gene for
|
||||
insertion of DNA
|
||||
Growth medium:
|
||||
• Ampicillin: Only successfully transformed
|
||||
bacteria carrying plasmids can survive in the
|
||||
presence of ampicillin
|
||||
• IPTG : activates transcription of the LacZ gene
|
||||
by binding its repressor
|
||||
• X-gal: β-galactosidase degrades X-gal. The
|
||||
product has a blue colour!
|
||||
|
||||
Day 3 - work overview
|
||||
✓ Purify plasmids
|
||||
✓ Restriction enzyme digestion
|
||||
✓ Run on agarose gel
|
||||
✓ Interpret results
|
||||
|
||||
Day 3: Material
|
||||
Spin column
|
||||
Tubes labeled with
|
||||
A1; A2; A3; A4; H2O
|
||||
Plasmid preparation kit
|
||||
Collection tube &
|
||||
spin column (blue)
|
||||
|
||||
Day 3: Plasmid purification
|
||||
→ performed during this lab (day 3)
|
||||
Buffer A1 (Cell Suspension)
|
||||
Tris/HCl (pH 8.0), EDTA, RNase A
|
||||
Buffer A2 (Cell Lysis)
|
||||
NaOH; SDS
|
||||
Buffer A3 (Neutralization/Binding)
|
||||
Contains acetate and guanidine
|
||||
hydrochloride
|
||||
Buffer A4 (Wash, reconstituted)
|
||||
Contains ethanol, NaCl, EDTA, and
|
||||
Tris/HCl
|
||||
|
||||
cells grown in LB-
|
||||
media overnight
|
||||
Transfer 2x 750 µl into
|
||||
microcentrifuge tube
|
||||
Bacterial pellet = cells + plasmid
|
||||
→ Discard superatant
|
||||
Balance the centrifuge
|
||||
Day 3: harvest cells & purify plasmids
|
||||
A1 - resuspension buffer
|
||||
A2 – cell lysis buffer
|
||||
A3 – neutralization/
|
||||
binding buffer
|
||||
Plasmid in supernatant
|
||||
cell debris as pellet
|
||||
transfer supernatant
|
||||
to column
|
||||
Plasmid binding
|
||||
Discard
|
||||
flow-through
|
||||
Wash with A4
|
||||
Transfer column to new tube
|
||||
add H2O to elute plasmid
|
||||
|
||||
QIAprep Miniprep Handbook, Appendix A: Background Information, Preparation of cell lysates, p 43
|
||||
Plasmid purification
|
||||
Buffer A1:
|
||||
Bacterial cells are resuspended in a buffer containing Rnase A.
|
||||
Buffer A2:
|
||||
Bacteria are lysed under alkaline conditions (NaOH). SDS solubilizes the phospholipid
|
||||
and protein components of the cell membrane
|
||||
Lysis and release of cells contents. Alkaline conditions: denaturation of chromosomal
|
||||
and plasmid DNA as well as proteins.
|
||||
Buffer A3:
|
||||
The lysate is neutralized and adjusted to high-salt-binding conditions. The high salt
|
||||
concentration causes denatured proteins, chromosomal DNA, cellular debris, and SDS
|
||||
to precipitate, while the smaller plasmid DNA renatures correctly and stays in solution.
|
||||
DNA is bound to silica membrane of spin columns in high-salt buffer. RNA, cellular
|
||||
proteins and metabolites are not retained on the membrane.
|
||||
Buffer A4:
|
||||
Washing and reconstitution of DNA. Salts are efficiently removed by this wash step.
|
||||
H2O:
|
||||
The purified plasmid DNA is eluted from silica membrane by addition of water. The
|
||||
elution is pe is dependent on a low salt concentration and a stable pH (pH 7-8.5).
|
||||
|
||||
Restriction enzyme working solution:
|
||||
Restriction enzyme buffer
|
||||
H2O
|
||||
Restriction enzyme (keep it cold!)
|
||||
Add restriction enzyme to a portion of eluted plasmid
|
||||
KEEP THE REST OF UNDIGESTED PLASMID AS CONTROLS FOR
|
||||
LATER USE Incubate at 37°C for 60 min
|
||||
Day 3: Restriction enzyme digestion
|
||||
|
||||
Day 3: Restriction enzyme digestion
|
||||
Plasmid without insert (2700 bp)
|
||||
Plasmid with insert in BamHI site (4200 bp)
|
||||
Cut with BamHI → bands at 2700 bp and 1500 bp
|
||||
|
||||
• Samples are mixed with 6x loading
|
||||
dye to make them ”heavier” to stay
|
||||
in wells
|
||||
• Separation of DNA molecules
|
||||
based on their size
|
||||
• DNA negatively charged
|
||||
• Agarose gel for separation
|
||||
• Shorter molecules move faster and
|
||||
migrate farther than longer ones
|
||||
• Visualization of DNA with SYBR
|
||||
safe DNA stain
|
||||
Day 3: Agarose Gel Electrophoresis
|
||||
|
||||
GeneRuler 1kb DNA ladder = size marker
|
||||
marker
|
||||
2700 bp
|
||||
1500 bp
|
||||
4200 bp
|
||||
Day 3: Expected Results
|
||||
|
||||
• Relaxed/linear: intact circle but “nick” in one strand
|
||||
• Linear: both strands are cut (at the same location)
|
||||
• Supercoiled: fully intact with both strands uncut, appears in a compact
|
||||
form
|
||||
Plasmid conformation affects migration
|
||||
|
||||
Lab schedule
|
||||
✓ Purify plasmids
|
||||
✓ Restriction enzyme digestion
|
||||
1-2h incubation time → lunchbreak and
|
||||
everyone will be back at the same time
|
||||
✓ Run on agarose gel
|
||||
approximately 1h → go through the
|
||||
expected results to be able to ask
|
||||
appropriate questions
|
||||
✓ Interpret results
|
||||
make sure to ask a lot of questions while you have
|
||||
the chance!!!
|
||||
|
||||
Lab reports
|
||||
✓ Write according to the guidelines on the handout on Canvas
|
||||
✓ One lab report per group (Names and group number on the cover page)
|
||||
✓ In English
|
||||
✓ Upload your lab reports on CANVAS, deadline 07/12/2025
|
||||
|
||||
Lecture Questions
|
||||
1. What are the sites the plasmid contains that allow for this experiment?
|
||||
2. What are the 3 compounds in the LB plates that allow for selection of
|
||||
bacteria with plasmid and the distinction of plasmids with and without
|
||||
the inserted gene?
|
||||
3. What are the six steps in plasmid preparation and purification?
|
||||
4. What is a restriction enzyme and why was it used in this experiment?
|
||||
5. Explain the principle of Gel Electrophoresis, what is it for?
|
||||
6. What´s the compound that allows for the visualization of the DNA in
|
||||
the gel?
|
||||
7. How many times does BamHI cut the plasmid without the insert? And
|
||||
the plasmid with the insert?
|
||||
8. Explain the different plasmid conformations that exist.
|
||||
@@ -1,219 +0,0 @@
|
||||
Recombinant DNA technology
|
||||
Lecture by:
|
||||
Anne Wöhr
|
||||
anne.wohr@gu.se
|
||||
|
||||
Recombinant DNA technology
|
||||
Molecular cloning Transformation Selection and
|
||||
Replication
|
||||
Performed during this lab
|
||||
|
||||
Plasmids
|
||||
• Commonly found in bacteria as extra-chromosomal
|
||||
circular dsDNA molecules
|
||||
• Able to self-replicate during cell division
|
||||
• Often carry beneficial genes like antibiotic resistance
|
||||
• Bacteria can share genetic information through
|
||||
plasmid transfer
|
||||
By: Maya Kostman
|
||||
How could this be useful for us?
|
||||
|
||||
Applications of recombinant DNA
|
||||
technologies
|
||||
Khan S., 2016
|
||||
Biopharmaceuticals:
|
||||
Vaccines eg hepatitis B vaccine
|
||||
recombinant proteins eg Insulin (Diabetes), Factor VIII (hemophilia)
|
||||
Genetically modified organisms:
|
||||
Organisms that have been genetically modified to exhibit specific traits eg
|
||||
herbicide-resistant crop plants
|
||||
Gene Therapy:
|
||||
In some genetic disorders, patients lack the functional form of a gene. Gene
|
||||
therapy attempts to provide a normal copy of the gene to the cells of the
|
||||
patient.
|
||||
Gene Analysis:
|
||||
build artificial, recombinant versions of genes that help understand how
|
||||
genes in an organism function
|
||||
|
||||
• Scissors: DNA restriction enzymes (DNA digestion)
|
||||
• Cutting sites: multiple cloning sites (MCS)
|
||||
• Glue: DNA ligase (DNA ligation)
|
||||
• Host: bacterial cells (Transformation)
|
||||
• Environment: LB medium or LB agar plates (Culturing)
|
||||
• Goal: making more identical copies, or expression (making proteins)
|
||||
Toolbox for molecular cloning
|
||||
|
||||
✓ DNA molecule that acts as a vehicle to carry foreign genetic materials
|
||||
into another cell, where it can be replicated or expressed.
|
||||
Vectors
|
||||
Ori (origin of replication):
|
||||
Replication is initiated here, enabling the plasmid to reproduce itself.
|
||||
MCS (multiple cloning site):
|
||||
Short segment of DNA which contains many restriction sites. This
|
||||
allows a piece of DNA to be inserted into that region. The used
|
||||
plasmid contains a BamHI cleavage site in its MCS.
|
||||
AmpR gene:
|
||||
encodes the enzyme beta-Lactamase, which inactivates ampicillin.
|
||||
Cells containing a plasmid vector which expresses AmpR can be
|
||||
selected from those that do not by growth in an ampicillin-containing
|
||||
medium.
|
||||
Lac promoter:
|
||||
binding site of RNA polymerase to initiate expression. IPTG binds
|
||||
and inactivates the LacI repressor protein and thereby enables
|
||||
expression of genes downstream of the promoter.
|
||||
LacZ⍺ gene:
|
||||
encodes the alpha-peptide of the enzyme beta-galactosidase.
|
||||
Functional beta-galactosidase consits of the alpha- and omega-
|
||||
peptide. The used E-coli strain carries the lacZ deletion mutant
|
||||
which contains the omega-peptide but lacks the alpha-peptide. The
|
||||
activity of mutant beta-galactosidase is rescued by the presence of
|
||||
the alpha-peptide present in the plasmid (alpha-complementation).
|
||||
|
||||
Restriction enzymes (Scissors)
|
||||
✓ Sequence-specific DNA endonucleases
|
||||
✓ Recognise and cleave DNA sequences at specific restriction sites
|
||||
✓ Generate “sticky end” or “blunt end”
|
||||
|
||||
Escherichia coli (Host)
|
||||
✓ Model organism in molecular biology
|
||||
✓ Gram negative, rod shaped bacteria
|
||||
✓ Located in lower intestine
|
||||
|
||||
The History of Insulin Production
|
||||
1921: Discovery of insulin
|
||||
1922: Leonard Thompson became the first person with diabetes ever
|
||||
treated through administration of insulin
|
||||
1923: Insulin is commercialized
|
||||
Insulin sales kit, Eli Lilly and Company, 1940s
|
||||
14 cows or 70 pigs to sustain a diabetic
|
||||
patient for 1 year
|
||||
1970: Recombinant DNA technology is
|
||||
developed
|
||||
1982: Recombinant insulin is commercialized
|
||||
|
||||
Production of Insulin
|
||||
Adapted from “From DNA to Beer: Harnessing Nature in Medicine & Industry”
|
||||
|
||||
Purpose of this lab:
|
||||
Determine whether a gene of interest has
|
||||
been successfully cloned into a vector.
|
||||
|
||||
Transformation
|
||||
|
||||
Transformation
|
||||
During the incubation
|
||||
on ice, DNA binds to
|
||||
the surface of the
|
||||
bacterium as a calcium-
|
||||
phosphate-DNA
|
||||
complex
|
||||
Following a sudden
|
||||
increase in
|
||||
temperature, one or
|
||||
more DNA molecules
|
||||
bound to the surface of
|
||||
the cell is taken up by
|
||||
the competent cell
|
||||
|
||||
How can we selectively grow bacteria
|
||||
that have taken up the plasmid?
|
||||
|
||||
Selection pressure
|
||||
✓ ampR gene encodes for beta-lactamase
|
||||
✓ Inactivates ampicilin antibiotics
|
||||
✓ Only cells containing vector DNA will grow
|
||||
in the presence of ampicilin
|
||||
Selection based on antibiotic resistance
|
||||
|
||||
How do we select for bacteria with the plasmids
|
||||
carrying the inserts?
|
||||
By: Maya Kostman
|
||||
|
||||
More detailed info: thermofisher.com
|
||||
LacZ gene naturally found in E. coli, encodes β-galactosidase.
|
||||
We use an E.coli strain that carries the LacZ deletion mutant which
|
||||
contains the omega-peptide but lacks the alpha-peptide and is therefore
|
||||
non-functional. The plasmid we use carries the alpha-peptide, rescuing the
|
||||
function of mutant beta-galactosidase.
|
||||
Blue-white screening
|
||||
|
||||
Lab Schedule
|
||||
• Monday (11/24)
|
||||
Introductory lecture 12:15 – 13:00
|
||||
Lab 13:15 – 14:00 Groups 1-19
|
||||
Lab 14:15 – 15:00 Groups 20-38
|
||||
• Tuesday (11/25)
|
||||
Lab 11:15 – 11:45 Groups 1-19
|
||||
Lab 12:00 – 12:30 Groups 20-38
|
||||
• Wednesday (11/26) Groups 1-19
|
||||
Introductory lecture 8:15 – 9:00
|
||||
Lab 09:15 – 16:00
|
||||
• Thursday (11/27) Groups 20-38
|
||||
Introductory lecture 8:15 – 9:00
|
||||
Lab 9:15 – 16:00
|
||||
Deadline for submitting lab reports: 07/12/2025
|
||||
|
||||
Working in the lab
|
||||
✓ Work in groups of 2 people, stick to your assigned partner
|
||||
✓ Always wear gloves and lab coat to protect you and your samples,
|
||||
wash your hands thoroughly before leaving the lab
|
||||
✓ When using the pipette, check the volume limits (0.1-10μl, 10-200μl,
|
||||
and 100-1000μl)
|
||||
✓ Pipette into the bottom of the tube, do not ”shoot” it (especially when
|
||||
working with very low volumes)
|
||||
|
||||
Transformation of competent cells
|
||||
→ performed during this lab (day 1)
|
||||
✓ 1 tube of plasmids (P) (with/without insert)
|
||||
✓ 1 tube of competent bacteria (C)
|
||||
|
||||
Day 1: Selection of transformed cells
|
||||
→ performed during this lab (day 1)
|
||||
✓ Pick up bacterial colonies (2 white, 2 blue) from plate
|
||||
✓ Grow in LB medium with antibiotics (expand the colony and replicate plasmids)
|
||||
Day 2: Picking & expansion of blue and white
|
||||
colonies
|
||||
→ performed during this lab (day 2)
|
||||
|
||||
Day 1: Materials for Transformation
|
||||
Falcon tube (50ml) LB-agar plate Eppendorf tube
|
||||
Day 1: Spread plate method
|
||||
o Apply light pressure to not tear or stab the agar
|
||||
|
||||
Day 3 - work overview
|
||||
✓ Purify plasmids
|
||||
✓ Restriction enzyme digestion
|
||||
✓ Run on agarose gel
|
||||
✓ Interpret results
|
||||
|
||||
Lab reports
|
||||
✓ Write according to the guidelines on the handout on Canvas
|
||||
✓ One lab report per group (your names and project group number on
|
||||
the cover page)
|
||||
✓ In English
|
||||
✓ Upload your lab reports on CANVAS deadline on 07/12/2025
|
||||
|
||||
Lecture Questions
|
||||
1. Name three applications of molecular cloning.
|
||||
2. What is a plasmid?
|
||||
3. Name the three main steps involved in recombinant DNA technology?
|
||||
4. What is a restriction enzyme?
|
||||
5. What are the bacteria used in your protocol?
|
||||
6. Explain the calcium/phosphate (heat-shock) method and what it is used for.
|
||||
7. How can we selectively grow bacteria that have taken up the plasmid?
|
||||
8. Explain the principle behind blue and white screening and its purpose in this
|
||||
lab.
|
||||
|
||||
References
|
||||
Kehoe A (1989). "The story of biosynthetic human insulin". In Sikdar SK, Bier M, Todd PW (eds.).
|
||||
Frontiers in Bioprocesssing. Boca Raton, FL: CRC Press. ISBN 978-0-8493-5839-5.
|
||||
https://www.sigmaaldrich.com/SE/en/technical-documents/technical-article/genomics/cloning-and
|
||||
expression/blue-white-screening
|
||||
https://www.nlm.nih.gov/exhibition/fromdnatobeer/exhibition-interactive/recombinant
|
||||
DNA/recombinant-dna-technology-alternative.html
|
||||
Khan, S., Ullah, M. W., Siddique, R., Nabi, G., Manan, S., Yousaf, M., & Hou, H. (2016). Role of
|
||||
Recombinant DNA Technology to Improve Life. International journal of genomics, 2016, 2405954.
|
||||
https://doi.org/10.1155/2016/2405954
|
||||
https://www.thermofisher.com/se/en/home/life-science/cloning/cloning-learning-center/invitrogen
|
||||
school-of-molecular-biology/molecular-cloning/cloning/traditional-cloning-basics.html
|
||||
|
||||