Highlights
- Fast: 80 - 90% of E.coli are lysed in only 10 minutes after harvesting.
- Simple 20 Second Transformation: No heat shock! Just add DNA and spread.
- DE3 Lysogen: Encodes the T7 polymerase for expressing recombinant proteins under the control of the T7 promoter.
Description
| Autolysis | Lyses easily. The parent strain JM109 itself will release about 20% of cellular protein after one freeze-thaw cycle. This strain will lyse in a wide range of buffer conditions. 80-90% of E. coli are lysed after a single freeze-thaw treatment. |
|---|---|
| Cell Growth | Grows well, especially when medium is supplemented with 1 mM Mg2+ |
| DNA Extraction | This strain is EndA- and yields high quality DNA preparations. |
| DNA Stability | The RecA- mutation in XJa stabilizes repetitive DNA sequences. |
| Genotype | F`[traD36 proA+B+ laclq ∆(lacZ)M15] ∆(lac-proAB) glnV44 (supE44)e14- (McrA-) thi gyrA96 (NalR) endA1 hsdR17(rK- mK+) relA1 recA1 ΔaraB::λR, cat (CmR), λ(DE3) |
| Processing Time | 10 minutes |
| Product Storage | -70°C to -80°C |
| Protein Expression | Suitable for general screening, but proteases may degrade small or otherwise unstable recombinant proteins. |
| Transformation Efficiency | 108 - 109 transformants per µg of plasmid DNA |
Q1: Can glycerol be present during the freeze-thaw cycle?
Do not perform the freeze and thaw cycle in a buffer containing glycerol. Glycerol protects the E.coli from forming ice crystals which are essential to the lysis of the cells.
Q2: What if the lysate is extremely viscous?
Depending on the amount of material used, the lysed material may become viscous, preventing efficient manipulation. However, for most applications it is not necessary to use a large amount of cell material. If necessary, vortexing vigorously for 30 seconds will decrease viscosity in most cases. Alternatively, a nuclease treatment (e.g. DNAse I) can be used to reduce viscosity. Diluting the cell lysate with additional buffer will also reduce viscosity issues.
Q3: How do you improve lysis efficiency?
If the results obtained are not satisfactory, lysis can be significantly improved by incubating the cells at higher temperatures (25 - 37°C) or for longer time (10 or 20 minutes) after thawing (step 5).
Q4: Will chitin be degraded?
Non-λ lysozyme usually is able to degrade chitin. However, the λ lysozyme expressed in these cells is not able to degrade chitin. λ lysozyme is a transglycosylase.
Q5: Is a starter culture necessary?
For best results, cells should not be growing actively prior to arabinose induction. This is achieved by using an overnight starter, where cells are already in the stationary growth phase, as stated in the protocol. If a fresher starter needs to be used, include arabinose already in the starter culture.
Q6: Can glucose be added to the growth media?
When glucose is added to the growth media, it inhibits the induction of the autolysis genes when it is present in the media. As the cells grow, they consume the glucose as a carbon source. Once the glucose has been consumed autolysis begins.
Q7: What buffer should the cell pellet be resuspended in?
Resuspend the cell pellet in water with or without 0.01% - 0.1% Triton X-100. For His-tag purification, resuspend in the His-Binding Buffer of the His-spin Protein Miniprep kit (Zymo Research product # P2001 or P2002). Acidic buffers and buffers containing higher concentrations of Mg2+ (>1 mM), and related metals that stabilize cell walls, inhibit lysis reaction to a various extent. If possible, add magnesium to the buffer after cells are lysed.
Q8: Are competent cells GMOs?
All our competent cells are classified into Biosafety level 1 and are not genetic modified organisms. Only when transformed with a plasmid they become GMOs.
Q9: Are the Mix & Go! strains dam+ and dcm+?
Most cloning strains will be dam+/dcm+ unless specifically noted in the genotype.
Q10: Do the Mix & Go! strains methylate DNA?
Yes
Q11: Which strains are equivalent to the Zymo strains?
DH5α is equivalent to Zymo 5α. DH10B, Top10, and One Shot Top10 are equivalent to Zymo 10B.For XL-21 Blue, JM109 is the closest match and for Stbl3, HB101 is the closest match.
Q12: How to reduce satellite colonies on agar plates?
– Prepare fresh agar plates– Use more antibiotics in plates– Incubate plates for a shorter time after plating cells
Q13: Is it possible to dilute the competent cells?
We do not recommend diluting the competent cells. We recommend using less DNA to transform cells, or aliquot cells in smaller volumes before transformation. If absolutely necessary, cold 1X Competent Buffer (Mix & Go Transformation Kit, T3001 & T3002) should be used in the dilution.
Q14: Which antibiotics can be used with the Mix & Go! procedure?
No outgrowth is necessary when using Ampicillin or Carbenicillin for selection. However, an outgrowth step is required when using Chloramphenicol, Kanamycin, and Tetracycline because of the mode of action of the antibiotic itself. We recommend the following procedure for the outgrowth step:1. Incubate cells on ice for 5-10 min after addition of plasmid. 2. Add 4 volumes of SOC media.3. Incubate at 37°C for 60 min with gentle shaking at 200-300 rpm.4. Spread on a pre-warmed culture plate containing the appropriate antibiotic.
Q15: Which Plasmid Size can be used for transformation?
For Zymo 5α and Zymo 10B up to 20kb. However, transformation efficiency decreases proportionally from 10-20kb. Above 20kb, cells are difficult to transform. JM109, HB101, XJa, XJa (DE3), XJb, XJb (DE3) and TG1 can handle constructs up to 10kb.
Q16: Which is the recommended DNA concentration and volume for transformation?
There really is no maximum or minimum recommended DNA concentration, but we use 10 pg for quality control. However, the volume of DNA added should not exceed 5% of the cells total volume; the efficiency can decrease several fold as the volume of DNA used increases. If the DNA sample is too diluted, use our DNA Clean & Concentrator.
Q17: What are some tips to improve transformation efficiency?
1. Thaw cells on ice, not room temperature.2. Incubate cells and DNA mixture on ice, not at room temperature. However, do not incubate longer then 1 hour.3. Ensure cells are still frozen when received.4. Pre-warm the culture plates at 37°C for at least 30 minutes.5. Prepare fresh LB agar plates containing the appropriate antibiotic. 6. Prepare a new DNA sample.7. Store the cells at -80°C (not 4°C or -20°C). If the freezer breaks, the cells should be OK as long as the temp does not go higher than -50°C.8. Avoid freeze/thaw cycles.
Q18: How will a heat-shock affect my Transformation Efficiency?
Heat shock is not necessary, however sometimes it can be beneficiary when preparing libraries or transforming XJb Autolysis E. coli strains.We recommend the following protocol for Heat Shock with Outgrowth: 1. Incubate cells on ice for 5-10 min after addition of plasmid. 2. Incubate cells at 42°C for 45 seconds.3. Add 450 ml of SOC to the cells.4. Incubate at 37°C for 60 min with gentle shaking at 200-300 rpm.5. Spread on a pre-warmed culture plate containing the appropriate antibiotic.
To clone new GFP-like fluorescent proteins from Obelia medusa, the authors identified the potential genes using expression libraries and cloned the genes into a vector. Expression of the proteins was facilitated by using XJb Autolysis E. coli cells from Zymo Research. The authors were able to purify three proteins from Obelia medusa that fluoresce in three different colors: cyan, green, and yellow.
Aglyamova, G.V. et al. (2011) Multi-colored homologs of the green fluorescent protein from hydromedusa Obelia sp. Photochem Photobiol Sci (8):1303-9.ebiomall.com
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国产的有上海宏石，枫岭，中山达安基因，上海科华生物，大约10-15万。
进口的有ABI公司的大约45万，罗氏诊断的大约40万，Bio-Rad的大约30万。
还需要反转录用的引物、定量PCR用的一对引物、荧光信号源（荧光染料或荧光标记的探针，看你用什么策略来做定量PCR）
报价要看你需要服务商提供什么服务，如果你只提供实验材料，要求服务商做以上全部工作，只检测一个指标（一个基因的表达水平变化），价格大约每个样品350-500元，多一个指标大约多90元。
一般至少做一组数据两个样品嘛，所以你按1000块一组样品预算吧。
标准品的荧光强度和已知的浓度作图，可以得到一条标准曲线。而待测样本的荧光强度测出以后，就可以在标准曲线上算出样本浓度了。
一般有ROX Reference Dye和ROX Reference Dye II两种,针对不同的PCR仪.一般ABI PRISM 7000/7700/7900HT和7300 Real-Time PCR System使用ROX Reference Dye,而7500 Real-Time PCR System和7500 Fast Real-Time PCR System使用ROX Reference Dye II.其它牌子如Thermal Cycler Dice Real Time System、LightCycler 等Real Time PCR扩增仪时不必使用.
1.模板提取（一般为RNA）：Trizol、氯仿、异丙醇、无水乙醇、DEPC处理水
2.模板浓度测定：分光光度计或NanoDrop
3.逆转录：逆转录试剂盒（或者一步法试剂盒），这一步可以用普通PCR做，也可以用水域做。
4.荧光定量PCR试剂：通常有用SYBR Green Mix做的，但是这里建议你用EvaGreen做，灵敏度和平行性都要好于SYBR Green，并且如果你那是ABI或者Stratagene的PCR如果用SYBR Green还需要加一步Rox很麻烦。
5.其他：除了以上的那些还需要离心管、PCR管或板（Axygen反应比较好）、移液枪等，暂时就想到这么多。
组织用Trizol法提取总RNA浓度、纯度都很好，但逆转录后跑PCR，CT值偏高，内参的在22-27之间，目的基因在30-36之间，不知道是怎么回事，如何来解决，求高手赐教。我用的Takara的试剂盒。
如果要测量细胞表面2个受体的比率，最好用流式细胞仪来测量
