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How do I calibrate my instrument for the CAL Fluor® and Quasar® Dyes?

CAL Fluor® and Quasar® dye calibration standards are designed to improve the accuracy of signal detection in real-time thermal cyclers that require spectral calibration. They enable the instrument to store the fluorescence profile of each dye and control for channel cross-talk. Crosstalk is the bleed-through of fluorescent signal from a reporter into an adjacent filter or channel, an issue of particular concern in a multiplexed assay. Many qPCR machines are pre-calibrated for Cy™3 and Cy5 dyes. In those machines, no calibration is necessary to use our Quasar 570 (Cy3 alternative) and Quasar 670 (Cy5 alternative) dyes. To use our CAL Fluor dye labels, particularly in a multiplexing assay, certain real-time PCR instruments need to be calibrated to anticipate crosstalk. LGC Biosearch Technologies does not make available pure dyes. Instead, our calibration standards are formulated to better mimic a fluorescent probe under experimental conditions by covalently linking the dye to an oligo-thymidine (dT10).  A complete list of available Calibration and Reference Dyes is available through our website. Instructions to calibrate select qPCR machines are available in our Spectral Calibration Instructions.

How do you determine the brightness of a dye?

The absolute intensity of a dye is a product of the extinction coefficient and the quantum yield. We have not measured the quantum yield for our dyes as this value is highly dependent upon the local environment, including the buffer system used for the measurement. However, we do provide the extinction coefficients for dye modifications at their lambda max wavelength, and these values are available under the Technical Specs tabs of our Oligo Modifications webpages. While quantum yield and extinction coefficients both contribute to dye detectability, the principal determinant for Stellaris® RNA FISH assays is actually the instrument optics, including the excitation source, available filters, and quantum efficiency of the camera.

Are there specific recommendations for performing 1-step RT-qPCR on RNA isolated from clinical samples?

PCRAMP-021

The nucleic acid (either DNA or RNA) will most likely need to be purified from clinical samples due to sample/transport media specific inhibitors and RNAses. For example, for RNA purification, we recommend our sbeadex‚Ñ¢ Pathogen Nucleic Acid Purification Kit for optimal purification.

Can Amp-Seq technology be used in human clinical diagnostics?

AMPSEQ-001
Currently, we are unable to support human clinical diagnostic applications.

Does Amp-Seq provide data analysis software to generate genotype calls?

AMPSEQ-001
Biosearch Technologies provides an analysis pipeline (the BiosearchCaller software), compatible with the Amp-Seq technology, to produce genotypes from the sequencing data. The software can be accessed via a cloud system and our technical team will support the deployment and initial setup.

Why are genotype calls not achieved for specific targets?

AMPSEQKIT1

Sometimes, despite a successful primer design for a target, genotyping calls are not achieved for a specific target. This can be caused by several issues including poor primer design and issues with the synthesis of the primers. In addition, if genomic reference data for both parental strains is not provided for target primer design, some primer pairs might not work for all F1 samples.

Missing genotypes are generally attributed to low depth. Certain targets cannot be amplified because of sample quality issues or unknown parental bias in the genomes. Our standard design process addresses the parental bias by avoiding primers on known variability in the genome. Known variation information can be provided to us in the target flanking sequences through the Data Submission form.

Which dyes are compatible with my thermal cycler?

LGC Biosearch Technologies offers many common fluorophores including FAM, HEX and TAMRA dyes, as well as our own proprietary dyes. Our CAL Fluor® and Quasar® dye series span the spectrum with emission wavelengths ranging from yellow to far-red, and represent alternatives to dyes such as VIC®, Cy™3, Texas Red, LC Red® 640, Cy5, and Cy5.5. For your convenience we have compiled a Multiplexing Dye Recommendations Chart outlining optimal dye combinations in select qPCR machines, as well as a Fluorophore & BHQ® Dye Selection Chart listing reporter-quencher pairings. In addition, you may use our Spectral Overlay Tool to visualize the absorption and emission spectra of multiple dyes together.

Can intercalating dyes be used with this mix?

BHQ-001

BHQ Probe Master Mix has been optimised for use with hydrolysis-probe based chemistry, for both end-point genotyping and qPCR applications. For use with intercalating dyes, we would recommend that you perform your own optimisation and validation to ensure reproducible sensitivity and specificity is achieved using your selected dye.

Why are genotype calls not achieved for specific targets?

AMPSEQ-001
Sometimes, despite a successful primer design for a target, genotyping calls are not achieved for a specific target. This can be caused by several issues including poor primer design and issues with the synthesis of the primers. In addition, if genomic reference data for both parental strains is not provided for target primer design, some primer pairs might not work for all F1 samples. Missing genotypes are generally attributed to low depth. Certain targets cannot be amplified because of sample quality issues or unknown parental bias in the genomes. Our standard design process addresses the parental bias by avoiding primers on known variability in the genome. Known variation information can be provided to us in the target flanking sequences through the Data Submission form.

Have you produced proteins at scale?

COMCEL-008

Our customers have reported growth of ClearColi strains in a 5 litre fermenter and shown optical density levels in excess of 150, and that some defoaming agents (particularly silicone-based defoamers) are beneficial while other defoaming agents such as polypropylene glycol may inhibit cell growth.