Tuesday, 28 February 2012

Protocol for the Blue White Colony Screening or Selection

Composition of LB Medium:

1.0% Tryptone 0.5% Yeast Extract 1.0% Sodium Chloride (NaCl) pH 7.0

Batch Protocol

Following Protocol makes 1 liter LB agar plates:

Dissolve 10 g Tryptone, 5 g yeast extract, and 10 g NaCl in 950 ml ultra pure water. Adjust the pH of the solution to 7.0 with NaOH. It may not be necessary to adjust pH every time, since pH of LB naturally close to pH 7.0. This might be affected by your reagents. Add 15 g agar. Complete the volume to 1 liter. Autoclave on liquid cycle for 20 minutes at 15 psi. Cool the media to 50 C in a water bath. Add 1 ml of X-Gal. Add 1 ml of 100 mM IPTG Solution. Add antibiotic for selection. Mix well and pour prepared LB agar into plates. Dry opened LB plates at room temperature under UV light for about half an hour.

Individual Plate Protocol

Add 40 µl of the X-Gal Solution (20 mg/ml). Add 10 µl of 100 mM IPTG Solution. Spread evenly on the plate with a sterile spatula. Dry the plate at 37°C. Spread bacteria evenly on the plate. Incubate overnight at 37°C.

Tuesday, 21 February 2012

IPTG a more effective inducer for the lac operon compared to lactose

IPTG is a substituted galactoside, where the glucose moiety of lactose is replaced by another chemical group.IPTG binds to repressor and inactivates it, but is not a substrate for β-galactosidase enzyme. IPTG is an effective inducer because of the following reasons:

1.One advantage of IPTG for in vivo studies is that it cannot be metabolized by E. coli, therefore the growth rate of cells (usually maintained with glycerol as the carbon and energy source), is not a variable in the experiment.

2. IPTG is not dependent on permease to enter the cell and is not cleaved by ßgalactosidase.So it is transported efficiently independent of whether the lacY gene is functional. And since cells don't metabolize IPTG, its concentration doesn't change during the course of an experiment.

Wednesday, 15 February 2012

IPTG (Isopropyl-β-D-Thiogalactopyranoside)

IPTG Isopropyl-β-D-Thiogalactopyranoside. An inducer of β-galactosidase used to promote the expression of proteins in cells controlled by the lac operator system. For blue/white screening, 0.1 mM final IPTG concentration in LB (Luria Broth) media is recommended.

IPTG is commonly used with X-Gal for blue/white colony screening. IPTG is an analog of lactose that inactivates the lac repressor and induces synthesis of β-galactosidase. The expression of cloned genes, that are under the control of the lac operon, is induced by IPTG .

IPTG (Isopropyl-beta-thio galactopyranoside) is white crystalline powder having Mol. wt.: 238.3, Purity: >99%.

1. IPTG is an inducer in cloning studies to allow  maximum expression of genes cloned in expression vectors.
2. It helps in stimulating the production of beta-galactosidase enzyme.
3. IPTG is a lactose analog which binds and inhibits  the lac repressor and thereby strongly induces beta-galactosidase production.

Product category : fine chemicals, reagents & buffer

Techncial Information:
Plant Cell Culture tested
Biotechnology Grade.
Dioxane free.

99% by TLC (9:1 Butanol:Water) Rf= 0.5
White powder
Molecular weight 238.3

Molecular Weight :238.31
Molecular Formula:C9H18O5S
Size:25 g
Catalog No.:21530057-3 ( 715052 )

Preparation of stock solution
Dissolve IPTG in water at 200 mg/ml. Sterilize solution through a 0.2 μm filter,dispense in small aliquots, and store at -20 °C. Such solutions usually are stablefor several months.


IPTG is intended for use in inducing expression from the lac promoter and its various derivatives.Use at a final concentration of 250-350 μg/mL in top agar and liquid cultures.Specific applications may require more or less IPTG .

See Reference

Download IPTG MSDS File
Buy ITPG From Supplier : bio-WORLD

See also:
IPTG (Isopropyl-β-D-Thiogalactopyranoside) - ( 1 g ) 21530057-1 ( 715053 ) - $20.06
IPTG (Isopropyl-β-D-Thiogalactopyranoside) - ( 5 g ) 21530057-2 ( 715058 ) - $28.46
IPTG (Isopropyl-β-D-Thiogalactopyranoside) - ( 50 g ) 21530057-4 ( 715054 ) - $182.58
IPTG (Isopropyl-β-D-Thiogalactopyranoside) - ( 100 g ) 21530057-5 ( 715056 ) - $445.00

Tuesday, 14 February 2012

Stable X-gal/IPTG non-toxic solution for use in blue/white colony screening in expression studies. It does not contain the toxic DMF and DMSO. The solution ...
IPTG Isopropyl-β-D-Thiogalactopyranoside. An inducer of β-galactosidase used to promote the expression of proteins in cells controlled by the lac operator ...

bioWORLD - Genomics, proteomics and bioaffinity matrices for gene expression, protein expression and cellular expression studies. IPTG Solution ...

Special savings for ordering X-GAL and IPTG at the same time. This product is sold for laboratory research use only.

Products 1 - 13 of 13 ... Special savings for ordering X-GAL and IPTG at the same time. ... Red-GAL is used in conjuction with IPTG for detection of B-galactosidase. ...
IPTG (Isopropyl-β-D-Thiogalactopyranoside) Solution, 100mM - Isopropyl-β-D- Thiogalactopyranoside, an inducer of β-galactosidase is used to promote the ...
IPTG Isopropyl-β-D-Thiogalactopyranoside. An inducer of β-galactosidase used to promote the expression of proteins in cells controlled by the lac operator ...

X-Gal-IPTG, Ready- to-use, Spray Stable X-gal/IPTG non-toxic solution For use in blue/white colony screening in expression studies Does not contain toxic DMF ...
IPTG (Isopropyl-β-D-Thiogalactopyranoside) is an inducer of β-galactosidase. It is used in conjunction with X-gal to promote the expression of proteins in cells ...
An iptg inducer is something which is being researched by the people at Plant Media. With scientific breakthroughs, developments like this might eventually be able to make gardening a much easier task for people around the world.
While some people think that growing a seedling is as simple as planting a seed in the ground and dumping water on it occasionally, it is not always this simple. There are many problems out there facing plants, and it is not always easy to get a seedling to mature into an actual tree or other type of plant. Different bacteria exist which can devastate a young plant quickly, and new developments may be forming to help reduce the number of problematic occurrences like this.
Botany experts stress that a proper environment is essential whenever you are gardening. Choosing the right plants for a particular setting can determine whether or not your garden will grow successfully. Some people are eager to attempt growing things which are not suited for their climate, and this can result in failed gardening experiences. Introducing foreign seedlings into certain areas could also bring bacteria and other problems into that region, and this can cause a whole range of problems for local gardeners.
Since Plant Media has been doing a tremendous amount of iptg research to help control common infections which certain plants are susceptible to, there has been some advancement in the world of gardening in general. Through the use of an iptg  inducer, it is thought that any type of iptg addition can reduce the time it takes for plants to fight infectious bacteria reproducing within it.
While plant cells are typically able to ward off bacteria relatively easily due to their cell walls, there are a few strains of infectious organisms which are capable of breaching the defenses of many plant species. This is one of the fundamental reasons why iptg research is important to the world.