Fungi Cultivation and Staining Techniques

Play an AI-generated podcast conversation about this lesson

What is a characteristic of the fungal cell wall that allows it to resist degradation by host cells?

It is composed of a single layer of glucan
It is composed of a single layer of mannan
It is composed of polysaccharides that are poorly degraded by host cells (correct)
It is composed of a single layer of chitin

What type of fungal hyphae is characterized by dark and pigmented septate hyphae?

Hyaline molds
Dematiaceous fungi (correct)
Racquet fungi
Coenocytic fungi

What is the main component of the peptidoglycan layer of the cell wall of bacteria?

Chitin
D-Mannose
D-Glucose
N-acetyl glucosamine (NAG) (correct)

What is the function of the cellular membrane in fungal cells?

It protects the cytoplasm and regulates the intake and secretion of solutes (C) Signup and view all the answers

What is the main target of antifungal drugs in the fungal cellular membrane?

Ergosterol (B) Signup and view all the answers

What is the function of the nucleus in fungal cells?

It is the control center of the cell (B) Signup and view all the answers

What is the function of the mitochondria in fungal cells?

It is the powerhouse of the cell (A) Signup and view all the answers

What is the characteristic of Cryptococcus neoformans that allows it to cause meningitis?

It can break the blood-brain barrier (C) Signup and view all the answers

What is the ideal relative humidity for incubating fungal cultures?

40-50% (D) Signup and view all the answers

Which of the following staining techniques is useful for identifying Candida?

Kinyoun's AFS Stain (C) Signup and view all the answers

What is the typical time frame for yeasts to grow in culture?

Within 24 hours to 4 days (B) Signup and view all the answers

What is the primary use of Brain-Heart Infusion Agar (BHI Agar)?

For the primary recovery of saprophytic and dimorphic fungi (D) Signup and view all the answers

What is the primary purpose of the culture method in fungal identification?

To observe fungal growth patterns and take note of microscopic details (C) Signup and view all the answers

What is the significance of observing hyphal shapes, septum, and cross walls in fungal identification?

To identify fungal species (D) Signup and view all the answers

What is the purpose of adding 10% sterile tartaric acid to Potato Dextrose Agar?

To lower the pH to about 3.5 to control bacterial growth (B) Signup and view all the answers

What should be done with a specimen if fungal culture cannot be performed immediately?

Refrigerate the specimen for a short time (B) Signup and view all the answers

Which medium is highly selective for dermatophytes and contains antibiotics such as cycloheximide and chloramphenicol?

Potato Flake Agar (D) Signup and view all the answers

What is the primary component of V-8 Agar that supplies trace ingredients needed to stimulate the growth of fungal elements?

V-8 juice (B) Signup and view all the answers

Which medium is recommended for the cultivation of yeasts and molds?

V-8 Agar (D) Signup and view all the answers

What is the advantage of using Potato Flake Agar for cultivating fungi?

It is advantageous for molds because diagnostically useful sexual reproductive structures develop more readily (C) Signup and view all the answers

What is the primary characteristic of tissue morphology in Phaeohyphomycosis?

Mycelial (mold form) (C) Signup and view all the answers

Which of the following fungi is NOT associated with subcutaneous Phaeohyphomycosis?

Histoplasma capsulatum (A) Signup and view all the answers

What is the characteristic of F. compacta?

Spherical with a broad base connecting the conidia (A) Signup and view all the answers

What is the primary difference between Phaeohyphomycosis and Chromoblastomycosis?

The type of dematiaceous fungi involved (A) Signup and view all the answers

What is the characteristic of Rhinocladiella?

Produces lateral or terminal conidia from conidiogenous cells (A) Signup and view all the answers

What is the primary purpose of using the Masson-Fontana stain in Phaeohyphomycosis?

To presumptively diagnose Phaeohyphomycosis (D) Signup and view all the answers

What is the characteristic of the lesions in lobomycosis?

Verrucose, ulcerative, painless lesions (A) Signup and view all the answers

What is the causative agent of rhinoentomophthoromycosis?

Entomophthora coronata (A) Signup and view all the answers

What is the treatment for subcutaneous phycomycosis?

Surgical excision and sulfa drugs (D) Signup and view all the answers

What is the characteristic of the fungal cells in lobomycosis?

Multinucleated, thick-walled, and exhibiting multiple budding (C) Signup and view all the answers

What is the laboratory diagnosis for lobomycosis?

Direct microscopic examination with PAS, methenamine silver, and FAT (C) Signup and view all the answers

What is the characteristic of the lesions in subcutaneous phycomycosis?

Small, firm, movable nodules (A) Signup and view all the answers

What is the causative agent of subcutaneous phycomycosis?

Basidiobolus haptosporus (B) Signup and view all the answers

What is the characteristic of the fungal growth in rhinoentomophthoromycosis?

Radial folds and thin aerial hyphae (D) Signup and view all the answers

What type of fungi is Dermatophytes an example of?

Anthropophilic (C) Signup and view all the answers

What is a characteristic of Dermatophytes?

They are resistant to cycloheximide (B) Signup and view all the answers

What is the characteristic of Dermatophytes that allows them to break down keratin?

They produce enzymes that can break down keratin (A) Signup and view all the answers

What is the typical habitat of Geophilic Dermatophytes?

Soil (D) Signup and view all the answers

What is the characteristic of Zoophilic Dermatophytes?

They can infect animals and humans (D) Signup and view all the answers

What type of immune response may be evoked by Cutaneous Mycoses?

Cellular immune response (C) Signup and view all the answers

What is the characteristic of the yeast phase of Blastomyces dermatitidis under microscopic examination?

Large, round, or oval cells with a single bud attached by a narrow base (C) Signup and view all the answers

What is the significance of the mycelial phase of Blastomyces dermatitidis?

It is characterized by delicate, septate, and branching hyphae resembling lollipops (C) Signup and view all the answers

What is the purpose of using Sabouraud Dextrose Agar/Inhibitory Mold Agar in the laboratory diagnosis of Blastomyces dermatitidis?

To cultivate yeasts and molds, and inhibit bacterial growth (A) Signup and view all the answers

What is the characteristic of the lesions in adult type Blastomyces dermatitidis infection?

Lesions in the mouth and tongue, affecting the lungs (B) Signup and view all the answers

What is the characteristic of Paracoccidioides brasiliensis under microscopic examination?

Small, septate, branched hyphae with intercalary and terminal chlamydospores (C) Signup and view all the answers

What is the significance of the yeast phase of Paracoccidioides brasiliensis under microscopic examination?

It has multiple buds attached to the parent cell by a narrow base (C) Signup and view all the answers

What is the purpose of using Brain-Heart Infusion Agar in the laboratory diagnosis of Blastomyces dermatitidis?

To cultivate yeasts and molds, and observe colony morphology (C) Signup and view all the answers

What is the characteristic of the lesions in primary cutaneous Blastomyces dermatitidis infection?

Lesions in the skin, affecting the lungs and brain (D) Signup and view all the answers

What is the significance of immunodiffusion tests in the laboratory diagnosis of Blastomyces dermatitidis?

It is more sensitive and specific than complement fixation tests (D) Signup and view all the answers

What is the characteristic of the growth of Blastomyces dermatitidis on Sabouraud Dextrose Agar/Inhibitory Mold Agar?

White, waxy, yeast-like, becoming cottony with white aerial mycelium (A) Signup and view all the answers

What is the purpose of adding 500μl of PBS to each well before adding the agarose solution?

To wash the cells and remove the culture medium (C) Signup and view all the answers

What is the concentration of agarose in the solution used to overlay the infected cells?

0.3% (D) Signup and view all the answers

Why is Fetal Bovine Serum (FBS) not used as a cell culture medium in the plaque assay?

Because it interferes with virus growth (D) Signup and view all the answers

What is the purpose of fixing cells with a 3.6% formaldehyde solution?

To preserve the cells for further analysis (C) Signup and view all the answers

What is the temperature at which the 3% agarose solution is pre-warmed before mixing with the culture medium?

45°C (B) Signup and view all the answers

What is the purpose of shaking the plates every 15 minutes during the incubation period?

To ensure uniform viral adsorption (D) Signup and view all the answers

What is the concentration of crystal violet used to stain the cells?

0.5% (A) Signup and view all the answers

What is the purpose of incubating the plates at 37°C for 60-84 hours?

To allow viral plaques to form (C) Signup and view all the answers

What is the primary purpose of using 0.7% soft agar in bacteriophage growth?

To visualize clear zones where bacterial cells have already lysed (A) Signup and view all the answers

What is the characteristic of primary cell lines?

They have a limited lifespan due to contact inhibition (C) Signup and view all the answers

What is the purpose of subculturing in cell culture?

To avoid 100% confluence, which would trigger mitosis and eventually lead to apoptosis (B) Signup and view all the answers

What is the characteristic of continuous cell lines?

They are 'immortal' and can be passed indefinitely (C) Signup and view all the answers

What is the purpose of Dulbecco's Modified Eagle Medium (DMEM) in cell culture?

To nourish and moisturize the cells (A) Signup and view all the answers

What is the application of cell culture in virus research?

To quantify the concentration of infectious viruses in a sample (C) Signup and view all the answers

What is the characteristic of Hep-2 cells?

They are a type of continuous cell line (A) Signup and view all the answers

What is the significance of the cell type that supports viral replication in cell culture?

It influences the time of detection of cytopathic effects (C) Signup and view all the answers

What is the purpose of overlaying the cell monolayer with a semi-solid medium?

To prevent the spread of the virus to neighboring cells (A) Signup and view all the answers

What is the typical time frame for plaque formation in the Plaque Assay?

3-14 days (A) Signup and view all the answers

What is the purpose of infecting the host cell monolayer with the virus at varying dilutions?

To ensure that the resulting plaques are countable and not too numerous or sparse (D) Signup and view all the answers

What is the unit of measurement used to calculate the number of viruses present in a sample?

Plaque-forming units (PFU) per sample unit volume (A) Signup and view all the answers

What is the purpose of preparing a confluently grown host cell monolayer?

To provide a layer of cells susceptible to the virus being tested (C) Signup and view all the answers

What is the role of the host cell monolayer in the Plaque Assay?

To provide a layer of cells susceptible to the virus being tested (C) Signup and view all the answers

What is the significance of the plaque formation in the Plaque Assay?

It indicates the area of cell death in the monolayer (A) Signup and view all the answers

What is the purpose of counting the plaques in the Plaque Assay?

To calculate the number of plaque-forming units (PFU) per sample unit volume (B) Signup and view all the answers

What is the primary purpose of adding gentamicin and amphotericin B to viral transport media?

To inhibit bacterial and fungal contaminants (A) Signup and view all the answers

What is the primary advantage of using fetal bovine serum in cell culture media?

It supports the growth of fastidious cells (A) Signup and view all the answers

What is the primary purpose of cryopreserving cells?

To allow for long-term storage of cells (C) Signup and view all the answers

What is the primary characteristic of continuous cell lines?

They can be passaged indefinitely (A) Signup and view all the answers

What is the primary application of cell culture in virology?

To isolate and propagate viruses (A) Signup and view all the answers

What is the primary purpose of using Hanks' balanced salt solution in cell culture?

To rinse cells before plating (D) Signup and view all the answers

What is the primary advantage of using serum-free media in cell culture?

It minimizes the effects of serum variability (D) Signup and view all the answers

What is the primary purpose of subculturing cells?

To expand cellular populations (B) Signup and view all the answers

What is the purpose of adding a chromogenic or chemiluminescent substrate to the membrane in a detection assay?

To catalyze a reaction that generates a detectable signal (C) Signup and view all the answers

What is the primary purpose of the Polymerase Chain Reaction (PCR) technique?

To identify viral agents through nucleic acid amplification (A) Signup and view all the answers

What is the role of the heat-stable DNA polymerase in the PCR process?

To catalyze the PCR reaction (D) Signup and view all the answers

What is the significance of the denaturation step in the PCR process?

To separate the DNA strands (A) Signup and view all the answers

What is the primary advantage of using PCR in molecular biology?

It permits the analysis of any sequence of DNA or RNA (C) Signup and view all the answers

What is the significance of using oligonucleotide primers in the PCR process?

To amplify a specific segment of DNA (B) Signup and view all the answers

What is the purpose of using a heat-stable DNA polymerase in the PCR process?

To withstand the high temperatures during the PCR process (B) Signup and view all the answers

What is the result of the PCR process?

The targeted DNA sequence is amplified (D) Signup and view all the answers

What is the characteristic of Hepatitis D virus that makes it not a full virus?

It borrows structures from HBsAg (B) Signup and view all the answers

During which stages of infection is the small delta antigen usually produced?

Early stages of infection (D) Signup and view all the answers

What is the primary way Hepatitis D virus is transmitted?

Through broken skin or contact with infected blood (C) Signup and view all the answers

What is the characteristic of the genetic material of Hepatitis D virus?

It is single-stranded and negative-sense (C) Signup and view all the answers

What is the purpose of HBsAg in Hepatitis D virus?

To provide structural proteins for the viral particle (C) Signup and view all the answers

What is the significance of the incubation period in Hepatitis D virus?

It is the time between infection and the onset of symptoms (B) Signup and view all the answers

What is the characteristic of the symptoms of Hepatitis D virus?

They are severe and chronic (D) Signup and view all the answers

What is the classification of Hepatitis D virus?

Genus: Deltavirus, Family: Kolmioviridae (B) Signup and view all the answers

What is the relationship between Hepatitis D virus and Hepatitis B virus?

Hepatitis D virus is a separate virus that requires Hepatitis B virus for replication (A) Signup and view all the answers

What is the high-risk group for Hepatitis D virus infection?

People with chronic Hepatitis B (C) Signup and view all the answers