Invitrogen™ Cholera Toxin Subunit B (Recombinant), Alexa Fluor™ 647 Conjugate

Catalog No.	Quantity
C34778	100 μg

Catalog No. C34778 Supplier Invitrogen™ Supplier No. C34778

Description

Made from a recombinant version of the B subunit only to provide a very high-purity product that is completely free of the toxic A subunit

• Cholera toxin B subunit (CT-B) attaches to cells by binding to ganglioside GM1, making it powerful tool for retrograde labeling of neurons
• This tracer has been used in variety of applications, including tracing of rat forebrain afferents, projections of parabrachial region, and neurons of the urinary bladder wall
• When used in neuronal tracing applications, CT-B is typically introduced by pressure injection or by iontophoretic injection into neural tissue
• Lyophilized product can be dissolved in buffer (e.g., PBS) for use
• More recently, researchers have found that CT-B can be used as a marker for lipid rafts, which are membrane microdomains enriched in cholesterol and sphingolipids thought to be important in cell signaling
• For lipid raft staining, cells are first incubated with fluorescent CT-B, then an anti-CT-B antibody is added to crosslink the CT-B in the lipid rafts into distinct patches on the plasma membrane
• These patches are easily visualized by fluorescence microscopy

• Label (Ex/Em): Alexa Fluor™ 647 (650/668nm)
• At neutral pH, the 11.4 kDa B subunit exists as a 57 kDa pentamer

Cell Analysis, Cell Structure, Cell Tracing and Tracking, Cell Viability, Proliferation and Function, Cellular Imaging, Endocytosis, Exocytosis and Phagocytosis, Immunofluorescence (IF), Immunofluorescence Staining and Detection, Lipid Rafts, Microbial Tracking, Neuronal Tracing

Order Info

Shipping Condition: Room temperature

Specifications

• Quantity: 100 μg
• Conjugate: Alexa Fluor 647
• Recombinant: Recombinant
• Content And Storage: Store in freezer (-5 to -30°C) and protect from light.
• Label Type: Alexa Fluor Dyes
• Shipping Condition: Room Temperature
• Protein Form: Recombinant
• Form: Lyophilized
• Protein Subtype: Cholera Toxin
• Product Line: Alexa Fluor

Frequently Asked Questions (FAQs)

I injected a fluorescent tracer, but cannot detect it after tissue is fixed and sectioned. What am I doing wrong?

Confirm that the tracer you are using crosslinks to proteins or has a primary amine for fixation-either a hydrazide, lysine fixable dextran, or a protein conjugate.
Use aldehyde-based fixatives to cross link the amines on the tracer.
Inject a larger amount or higher concentration of the tracer. Tracers are generally injected at 1-20% concentrations (10 mg/mL or higher).
Confirm that you are using the correct fluorescent filter for detection. You can perform a spot test by pipetting a small amount of the undiluted stock solution of the tracer onto a slide, then view under the filter you are using on your microscope. This will confirm if the tracer fluorescence can be detected and the fluorescent microscope filter is working properly.
Review tissue fixation and handling procedures to confirm if any reagents or processing procedures could be affecting the tracer.

Do you have a tracer that will only transport retrograde?

Wheat germ agglutinin and cholera toxin conjugates have been used for retrograde tracing. They may have some anterograde tracing in some applications. A selection guide can be found here (https://www.thermofisher.com/us/en/home/life-science/cell-analysis/cell-tracing-tracking-and-morphology/neuronal-tracing/protein-conjugates.html).

How do I know which tracer to choose for my experiment?

Factors to consider are size of tracer, method of delivery (injection, direct application to tissue, etc.), and if the tracer needs to be fixable. Here are some links to details about the various classes of neuronal tracers we offer and how to choose between them:

Neuronal Tracing (https://www.thermofisher.com/us/en/home/life-science/cell-analysis/cell-tracing-tracking-and-morphology/neuronal-tracing.html)
Choosing a Tracer (https://www.thermofisher.com/us/en/home/references/molecular-probes-the-handbook/fluorescent-tracers-of-cell-morphology-and-fluid-flow/choosing-a-tracer.html)
Imaging Analysis (http://assets.thermofisher.com/TFS-Assets/BID/Reference-Materials/bioprobes-50-journal.pdf)

What products do you have for neuronal tracing?

Please check out this web page (https://www.thermofisher.com/us/en/home/life-science/cell-analysis/cell-tracing-tracking-and-morphology/neuronal-tracing.html) for details.

For Research Use Only. Not for use in diagnostic procedures.