Ebpay

    Candida tropicalis filamentation assay with fluconazole

    Laboratorio de Microbiología Mr JORGE ENRIQUE PEREZ CARDENAS, Sebastian Hernandez

    Published: 2021-12-24 DOI: 10.17504/protocols.io.bxh8pj9w
    AI 解读
    浏览 1756

    Abstract

    This protocol was used to obtain enough quantity of RNA of a nonsusceptible strain of Candida tropicalis, with the goal to do a transcriptomic analysis to demonstrate the degree of differential expression of genes under filamentation and non-filamentation conditions and against a non-filamenting strain, susceptible to fluconazole ( Candida tropicalis ATCC750)

    Steps

    RPMI PREPARATION

    1.

    MEDIA PREPARATION

    1.1.

    Medium to inhibit filamentation (RPMI+NAC)

    RPMI1640: 10g

    3-[N-morpholino]propane sulfonic acid buffer (MOPS): 35 g

    N-acetyl glucosamine: 20 g

    Distilled water 500 ml

    Adjust pH at 7.0

    Adjust volume at 1000 ml

    Esterilize by filtration

    1.2.

    MEDIUM TO PROMOTE THE FILAMENTATION (RPMI+SFB)

    RPMI1640: 10g

    3-[N-morpholino] propane sulfonic acid buffer (MOPS): 35g

    Glucose: 20 g

    Distilled water: 500 ml

    Adjust pH at 7.0

    Adjust volume at 1000 ml

    Add 10% of Fetal bovine serum

    2.

    Fluconazole preparation

    Weigh 6.4 mg of Fluconazole (Cat Sigma: F8929)

    Dissolve in 1 ml of Dimethyl sulfoxide (DMSO)

    aliquot and freeze at -80°C

    2.1.

    FLUCONAZOLE (FLU) DILUTION

    USE A V or U bottom 96 wells plate

    ABCDEFGHIJK
    DMSO5075175
    FLU 6400 µg/mL502525
    DMSO5075175
    FLU 800 µg/mL502525
    DMSO5075175
    FLU 100 µg/mL502525

    Susceptibility test

    3.

    INOCOLUM DILUTION

    Cultivate Candida tropicalis in Potato dextrosa agar o in Liquid Sabouraud

    Incubate for 24 h at 35°C

    Dilute one or two colonies in sterile saline solution

    Vortex until homogeinity

    Adjust the turbidity according to the 0.5 MacFarland Standard (1x106-5x 106CFU)

    Make a 1:100 dilution of the inocolum using each media (filamentation and No fiamentation)

    Vortex for 15 seg

    Make a 1:20 dilution using the 1:100 dilution, using the same media (Final yeast concentration: 5x102 to 3x103 FCU

    4.

    MIC ASSAY USING MEDIA TO FILAMENTATION (SFB) AND MEDIUM TO INHIBIT THE FILAMENTATION (NAC)

    USE A STERILE 24 WELLS PLATE

    RPMI + NAC

    ABCDEFG
    RPMI+NAC90 µL90 µL90 µL90 µL90 µL90 µL
    FLU (dil)10 µL (6400 µg/mL)10 µL (3200 µg/mL)10 µL (1600 µg/mL)10 µL (800 µg/mL)10 µL (400 µg/mL)10 µL (200 µg/mL)
    INOCULUM (dil 1:20)900 µL900 µL900 µL900 µL900 µL900 µL
    REAGENTS1 µg/ml0.5 µg/ml0.250 µg/ml0.125 µg/mlC+C-
    RPMI+NAC90 µL90 µL90 µL90 µL90 µL1000 µL
    FLU (dil)10 µL (100 µg/mL)10 µL (50 µg/mL)10 µL (25 µg/mL)10 µL (12.5 µg/mL)
    DMSO10 µL
    INOCULUM (dil 1:20)900 µL900 µL900 µL900 µL900 µL

    C+: Positive control; C-: negative control

    RPMI+SFB| A | B | C | D | E | F | G | | --- | --- | --- | --- | --- | --- | --- | | RPMI +SFB | 90 µL | 90 µL | 90 µL | 90 µL | 90 µL | 90 µL | | FLU (dil) | 10 µL (6400 µg/mL) | 10 µL (3200 µg/mL) | 10 µL (1600 µg/mL) | 10 µL (800 µg/mL) | 10 µL (400 µg/mL) | 10 µL (200 µg/mL) | | INOCULUM (dil 1:20) | 900 µL | 900 µL | 900 µL | 900 µL | 900 µL | 900 µL | | REAGENTS | 1 µg/mL | 0.5 µg/mL | 0.25 µg/mL | 0.125 µg/mL | C+ | C- | | RPMI+SFB | 90 µL | 90 µL | 90 µL | 90 µL | 90 µL | 1000 µL | | FLU (dil) | 10 µL (100 µg/mL) | 10 µL (50 µg/mL) | 10 µL (25 µg/mL) | 10 µL (12.5 µg/mL) | | | | DMSO | | | | | | | | INOCULUM (dil 1:20) | 900 µL | 900 µL | 900 µL | 900 µL | 900 µL | |

    C+: Positive control; C-: Negative Control Incubate at 35°C for 24 hrs with constant agitation (200 rpm approx.)

    Read using an inverted microscope, comparing controls with each well

    The Minimal inhibitory concentration will be where was observed 50% or more of growth

    Also, register the filamentation grade in each well

    5.

    CULTURE OF C. tropicalis TO HARVEST YEAST FOR TRANSCRIPTOMIC ANALYSIS

    Obtain a Fluconazole Strain and a certificate strain (ATCC750)

    Establish the susceptibility grade of both strains

    Culture both strains with filamentation (RPMI+SFB) and Non-filamentation (RPMI+NAC) media, using Fluconazole at subinhibitory concentrations

    Incubate at 35°C by 24 hrs with constant agitation (200 rpm)

    Check the growth degree and filamentation degree

    Harvest the colonies with a sterile Pasteur pipet

    Centrifuge at high speed

    Extract the supernatant

    Add RNA later (Sigma Aldrich Ref0901)

    Freeze at -80°C until the RNA extraction

    6.

    推荐阅读

    Nature Protocols
    Protocols IO
    Current Protocols
    扫码咨询