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Frequently Asked Questions

Select your question:

Transilluminators

Electrophoresis

Bacterial Strains

Stains

Electronic Imaging

Transilluminators

  • What is the wavelength of the UV bulbs in my transilluminator?

    FOTODYNE transilluminators come standard with 312 nm UV bulbs. 366 and 254 nm bulbs can also be ordered. The wavelength range and peak for each bulb can be found by clicking on the desired bulb below.

  • I want to use my UV transilluminator for crosslinking. What is the energy output of the transilluminator?

    The energy output of a FOTODYNE transilluminator equipped with 312 nm UV bulbs is approximately 4,000 µW/cm2.

    NOTE: The optimal energy for crosslinking has been reported to be approximately 1600 Joules per square meter of wet membrane and 160 Joules per square meter of dry membrane. There are many variables in the blotting and crosslinking procedure that may influence the length of time required to expose a membrane to UV light for optimal crosslinking. These may include: brand and type of membrane, size and type of nucleic acid, wetness of membrane, age and condition of UV bulbs, transfer buffer composition, etc. Therefore the best crosslinking conditions should always be determined empirically for the exact experimental system being used.

  • How do I calculate the UV dosage for crosslinking?

    Calculations:
    Energy = Power x Time
    Time = Energy / Power

    For a dry membrane: Time = (160 Joules/m2) / (40W/m2)
    4 seconds
    For a wet membrane: Time = (1600 Joules/m2) / (40W/m2)
    ~ 40 seconds

    NOTE: The optimal energy for crosslinking has been reported to be approximately 1600 Joules per square meter of wet membrane and 160 Joules per square meter of dry membrane. There are many variables in the blotting and crosslinking procedure that may influence the length of time required to expose a membrane to UV light for optimal crosslinking. These may include: brand and type of membrane, size and type of nucleic acid, wetness of membrane, age and condition of UV bulbs, transfer buffer composition, etc. Therefore the best crosslinking conditions should always be determined empirically for the exact experimental system being used.

  • How do I change the UV bulbs in my transilluminator?

    To save time and money, it is important to determine whether a bulb that does not light has burned out, or whether a ballast is defective. First, the filter frame and filter glass must be removed in order to access the UV bulbs. Next, the bulb that does not light should be exchanged with a good bulb from a properly functioning ballast (i.e. a ballast in which both bulbs light). If the bulb in question does not light, then a bulb replacement is in order. If the bulb does light, then a ballast needs to be replaced.

    Bulb Replacement
    Grasp the metal collar on each end of the bulb with the thumb and first finger. Gently rotate the bulb and pull it out of its socket. Do not force the bulb. Do not use excessive pressure and do not hold the bulb in the center. Replace the old bulb with the new one by following the instructions in reverse.

    Ballast Replacement
    To replace a defective ballast contact FOTODYNE for assistance by calling 800-362-3686.

  • How do I replace the fuse(s) in my transilluminator?

    Unplug the transilluminator and locate the fuse compartment above the power cord receptacle on the back of the unit. Open the fuse cartridge by lifting the tab on the lower edge of the cartridge. It may then be pulled directly out of the unit. Remove the fuse and visually inspect it for burn-out. Replace the bad fuse with the appropriate replacement (see below).

    FOTODYNE Transilluminator
    (Model Number)
    Voltage Catalog Number of Fuse
    FOTO/Phoresis UV (1-1430)
    (1-1432 & 1-1434)
    120 V
    220 & 240 V
    77-2055
    77-2065
    FOTO/UV 15, 21 or 26
    (3-3115, 3-3121, 3-3045)
    (3-3117, 3-3123, 3-3047)
    (3-3119, 3-3125, 3-3049)
    -
    120 V
    220 V
    240 V
    -
    77-2051
    77-2069
    77-2071
    FOTO/Convertible (3-3455)
    (3-3457 & 3-3459)
    120 V
    220 & 240 V
    77-2051
    77-2071
    FOTO/Prep (3-3500)
    (3-3502CE & 3-3504CE)
    120 V
    220 & 240 V
    77-2021
    77-2051
    FOTO/UV 300 (3-3000)
    (3-3002CE & 3-3004 CE)
    120 V
    220 & 240 V
    77-2021
    77-2051
    FOTO/UV 450 (3-4500)
    (3-4502 & 3-4504)
    120V
    220 & 240 V
    77-2019
    77-2059
      120V
    220 & 240 V
     

     

  • How do I install a UviClear transparent glass protector?

    To replace a worn or degraded UviClear, remove the screws that attach it to the top of the UV transilluminator. Align the new UviClear with the screw holes and tighten all the screws completely.

    NOTE: If your FOTO/Prep transilluminator has a removable (magnetic) UViClear, do not remove any screws. Merely lift the worn UviClear and set the new UviClear in its place.

    Exposure to ultraviolet light causes eventual solarization of the UviClear Transparent Protector, which reduces the intensity of transmitted UV light. Replacement of the UviClear is recommended after approximately 50 hours of use.

    FOTODYNE Transilluminator Catalog Number of
    UviClear Transparent Glass Protector
    FOTO/UV 15, 21 or 26 3-4474
    FOTO/Convertible 3-4473
    FOTO/Prep 3-4475
    FOTO/UV 300 3-4460
    FOTO/UV 450 3-4460
    FOTO/Flex Large-Format UV & Convertible 3-3214

     

  • My DNA bands look less intense than they used to. What is wrong with my transilluminator?

    Exposure to ultraviolet light causes eventual solarization of the UviClear Transparent Protector, which reduces the intensity of transmitted UV light. Replacement of the UviClear is recommended after approximately 50 hours of use.

Electrophoresis

  • My electrophoresis gel run is taking too long. What could be causing this?

    First check your Voltage setting. Generally, a voltage setting of 100-120 Volts run for 45 minutes to 1 hour is used for agarose gels ranging from 0.5%-4% agarose. Polyacrilymide gels should generally be run at voltages ranging from 150-200 Volts, depending again on the percentage of the polyacrilymide used.

    Next, make sure your running buffer is at the correct concentration. 1X TBE buffer is generally used for agarose gel electrophoresis. If you have been using the same buffer in the electrophoresis chamber and feel that some of the liquid has evaporated (making the buffer more concentrated) change the buffer and try the gel run again.

Bacterial Strains

  • Why isn't my bioluminescent E. coli glowing?

    Strains containing lux operon clones should be incubated at room temperature for 2-3 hours to allow expression of bioluminescence. Bioluminescent strains are not viable in stabs for long periods of time. They should be grown out and stored in the appropriate media in an ultra cold freezer or transferred every 1-2 months. All bioluminescent strains should be grown at room temperature not at 37ºC. Dark mutants are also fairly common especially after repeated culturing.

Stains

  • There are many DNA stains, protein stains and other dyes to use. How do I know if they are compatible with my FOTODYNE imaging system?

    Please refer to table below for a list of common biological stains and dyes, their excitation and emission spectra and the FOTODYNE filter and bulb that is recommended.

    If you don't see your stain or dye on the table, refer to Table 2 (below) to see if your dye fits in the excitation range of our bulbs and Table 3 (below) for our filters. Please note that FOTODYNE can customize your filter. Contact customer service for more information.

    Bulb Type Approximate Peak Approximate Range Relative Energy Curve
    Short - (254 nm) UV Bulb 254 nm 235 - 300 nm see 254 curve
    Mid - (312 nm) UV Bulb 312 nm 275 - 350 nm see 312 curve
    Long - (366 nm) UV Bulb 366 nm 325 - 390 nm see 366 curve

     

    Filter Type Bandwidths % Transmittance Curve
    Fluorescent Green 500 - 550 nm see transmittance curve
    Fluorescent Gold 530 - 570 nm see transmittance curve
    Ethidium Bromide 550 - 650 nm see transmittance curve

     

  • How many microliters of 1X loading dye do I need to add to my dried down DNA samples in MolecuLabs 207/208 and 105/106?

    MolecuLab 207/208 you need to add 15 ul of 1X loading dye.
    MolecuLab 105/106 you need to add 15 ul of 1X loading dye.

  • How much FOTO/Vision DNA stain should I add to my DNA sample?

    Add 1 μL of FOTO/Vision DNA stain per 5 μL of DNA sample. No extra loading dye needs to be added. Simply load your samples onto your gel and run your electrophoresis as normal.

Electronic Imaging

  • I see "stripes" on my images and/or thermal prints. What is going on here?

    Check to see that the proper electronic imaging filter is being used with your FOTO/Analyst electronic imaging system.

    Unlike conventional cameras, the array of the FOTO/Analyst CCD camera is sensitive to infrared radiation. If you try to use standard cut-off type filters or do not use a filter, the bulbs of your transilluminator will be visible in the resulting image. FOTODYNE offers a variety of bandpass filters to fit your imaging application.

  • Can I image gels with blue light imaging?

    FOTODYNE Imaging systems are compatible with blue light transilluminators and UV-converted blue light. Refer to Blue Light Imaging FAQ for more info.

  • Can I use my Polaroid filters with my FOTO/Analyst Apprentice digital imaging system?

    You should not use Polaroid camera filters with your Apprentice system because Polaroid filters and digital filters use different principles to filtering light for imaging. Polaroid camera filters are cut-off filters and cut-off light after a certain wavelength. These filters do not filter out infrared light; this is ok with Polaroid cameras because the film is not sensitive to infrared light. Digital imaging systems are more sensitive to infrared light so this light will interfere with the image if it is not filtered-out. The type of filter used for digital imaging is called a band-pass filter. This type of filter allows only specific wavelengths of light to pass through the filter therefore allowing for greater control of the wavelengths of light that are used when imaging.

  • What settings should I use on my Apprentice camera system to image my stained gel?

    Settings will vary depending on the quality of the gel and stain used. Suggested settings are listed below. Adjust your Aperture and Exposure settings accordingly to obtain as much information as you need from your gel.

    Stain   Aperture settings
    (f-stop)
      Exposure
    Time
    SYBR Green   2.8   4
    SYBR Safe   2.8   4
    Ethidium Bromide   2.8   4
    FOTO/Vision   2.8   4
    Coomassie Blue   1/10   8
    Methylene Blue   1/10   8

     

  • Can you recycle my old Polaroid hood to fit my FOTO/Analyst Apprentice camera system?

    As much as FOTODYNE would love to recycle any components from older Polaroid systems, hoods have to be specially tooled to allow for the correct bracket mountings for the digital camera that makes-up the Apprentice system. Hoods may be placed in the general plastics recycling bin at your institution.