Podcast
Questions and Answers
Which surface texture of fungal colonies is characterized as appearing mostly wrinkled?
Which surface texture of fungal colonies is characterized as appearing mostly wrinkled?
- Velvety or Silky (correct)
- Granular or Powdery
- Moist
- Cottony or Woolly
What is a primary disadvantage of using KOH or LPCB in fungal colony sampling?
What is a primary disadvantage of using KOH or LPCB in fungal colony sampling?
- It can damage the vegetative spores.
- It is not effective for systemic fungi sampling.
- It limits sampling to reproductive spores only. (correct)
- It destroys the morphology of the fungi.
Where is the best place to observe the pigmentation of fungi?
Where is the best place to observe the pigmentation of fungi?
- On the top surface of the medium
- Under bright light
- On the underside of the medium (correct)
- In the surrounding environment
What is a primary advantage of the hair baiting technique in fungal culture sampling?
What is a primary advantage of the hair baiting technique in fungal culture sampling?
What is primarily observed when sampling fungal colonies?
What is primarily observed when sampling fungal colonies?
Which type of surface texture of a fungal colony is described as cottony or woolly?
Which type of surface texture of a fungal colony is described as cottony or woolly?
What form do dimorphic fungi take at 37°C?
What form do dimorphic fungi take at 37°C?
What is the optimum temperature range for saprophytic molds?
What is the optimum temperature range for saprophytic molds?
Which feature is characteristic of molds?
Which feature is characteristic of molds?
How long should fungal cultures be incubated for optimal growth?
How long should fungal cultures be incubated for optimal growth?
What type of reproduction do molds use?
What type of reproduction do molds use?
What is the standard incubation temperature for fungi?
What is the standard incubation temperature for fungi?
Which of the following is NOT a form of fungal growth?
Which of the following is NOT a form of fungal growth?
What factor can induce a dimorphic fungus to change its form?
What factor can induce a dimorphic fungus to change its form?
What is the typical growth temperature range for parasitic fungi?
What is the typical growth temperature range for parasitic fungi?
What process forms a new yeast cell?
What process forms a new yeast cell?
What happens to a yeast bud once it has formed?
What happens to a yeast bud once it has formed?
What is binary fission in the context of yeast?
What is binary fission in the context of yeast?
Which of the following represents how a yeast cell duplicates its genetic material?
Which of the following represents how a yeast cell duplicates its genetic material?
Which type of diseases can Griseofulvin be used against?
Which type of diseases can Griseofulvin be used against?
What type of bacteria can cephalosporin target?
What type of bacteria can cephalosporin target?
What is typically true about higher fungi?
What is typically true about higher fungi?
How does a yeast cell ensure that each new organism receives DNA during division?
How does a yeast cell ensure that each new organism receives DNA during division?
During mitotic division, what is the phase where the cell divides its cytoplasm called?
During mitotic division, what is the phase where the cell divides its cytoplasm called?
Which characteristic describes budding in yeast?
Which characteristic describes budding in yeast?
What type of hyphae do Penicillium exhibit?
What type of hyphae do Penicillium exhibit?
Which structure is characteristic of Rhizopus?
Which structure is characteristic of Rhizopus?
What is the function of phialides in fungi like Penicillium?
What is the function of phialides in fungi like Penicillium?
Which of the following fungi has nonseptated hyphae with no rhizoids?
Which of the following fungi has nonseptated hyphae with no rhizoids?
Which of the following statements is true about Phialophora?
Which of the following statements is true about Phialophora?
What are the structures in Rhizopus that support the sporangium?
What are the structures in Rhizopus that support the sporangium?
In which fungi are conidiospores arranged in chains?
In which fungi are conidiospores arranged in chains?
What type of hyphae is characteristic of Mucor?
What type of hyphae is characteristic of Mucor?
Which fungal structure is flask-shaped and contains conidiospores?
Which fungal structure is flask-shaped and contains conidiospores?
What is the role of sporangiophores in fungi?
What is the role of sporangiophores in fungi?
What characteristic do dematiaceous fungi exhibit?
What characteristic do dematiaceous fungi exhibit?
What type of patients are most commonly affected by fungal meningitis caused by dematiaceous fungi?
What type of patients are most commonly affected by fungal meningitis caused by dematiaceous fungi?
Where are dematiaceous fungi commonly found?
Where are dematiaceous fungi commonly found?
What is used to identify the capsule of Cryptococcus neoformans?
What is used to identify the capsule of Cryptococcus neoformans?
What visual characteristic indicates dematiaceous fungi when hyphae are observed?
What visual characteristic indicates dematiaceous fungi when hyphae are observed?
What does a clear halo against a dark background indicate in the India ink preparation?
What does a clear halo against a dark background indicate in the India ink preparation?
Which of the following describes the colonies of dematiaceous fungi?
Which of the following describes the colonies of dematiaceous fungi?
What type of staining method is demonstrated by using India ink?
What type of staining method is demonstrated by using India ink?
What type of fungal infection can dematiaceous fungi cause?
What type of fungal infection can dematiaceous fungi cause?
A sample observed with brown-colored hyphae would most likely be categorized as what type of fungus?
A sample observed with brown-colored hyphae would most likely be categorized as what type of fungus?
Study Notes
Molds
- Are multicellular
- Have a filamentous, branching form
- Grow at room temperature
Dimorphism vs. Monomorphism
- Dimorphic fungi are able to exist in both mold and yeast forms
- This change is usually triggered by environmental conditions, such as temperature
- For example, they exist as yeasts at 37°C (body temperature) and molds at room temperature
- Thermally dimorphic fungi are an example of dimorphism
Fungal Cultures
- Saprophytes (molds) have an optimal temperature for growth of 20-30°C
- Parasitic fungi (yeasts) have an optimal temperature for growth of 30-37°C
- The standard incubation temperature for fungal cultures is 30°C
- Fungal cultures are incubated in a humidified environment for 21 days
- Bacterial cultures require an incubation temperature of 37°C
Fungal vs Bacterial Cultures
- Fungal cultures are clinically important in the diagnosis and treatment of fungal infections
- Anti-fungal medications are used to treat infections caused by fungi
Fungal Reproduction
- Fungi can reproduce sexually or asexually
- Asexual
- Budding: a new cell is formed through mitotic division and remains attached to the parent cell until it splits
- Binary fission: a yeast cell replicates its genetic material (DNA) and then divides into two parts, with each receiving one copy of DNA
- Asexual
- Sexual: Involves the fusion of gametes or nuclei from two parent organisms, resulting in the formation of spores.
Dematiaceous Fungi
- Produce melanin in their cell walls
- Have a characteristic brown color when grown on agar
- Have dark colonies and pigmented fungal elements
- India Ink Wet Mount: used to identify the capsule of Cryptococcus neoformans (a dematiaceous fungus)
- CSF is examined by adding one drop of India ink
- The capsule appears as a clear halo against a dark background (negative staining)
Penicillium
- Septate hyphae with a conidiophore that exhibits branching to form metulae
- Brush-like conidiophore (metulae) give rise to phialides with conidiospores
- Spores are arranged in chains
Phialophora
- Septate hyphae with flask-shaped phialides with cup-shaped collarettes with conidiospores
- NO CONIDIOPHORE
Rhizopus
- Nonseptated hyphae
- With rhizoids (root-like structures)
- With sporangiophores (stalk-like structures)
- With sporangium (sac-like structure)
Mucor
- Nonseptated hyphae with no rhizoids
- Sporangiophores arise singly with a sac called sporangium
- Sporangium contains sporangiospores
Topography of Fungal Cultures
- It's important to observe the surface texture and pigmentation of fungal colonies.
- Surface texture can be:
- Cottony or woolly
- Velvety or silky
- Granular or powdery
- Moist
- Pigmentation can be observed on the surface or on the reverse side of the culture medium
- Cellophane Tape Preparation:
- Used to sample sporulating fungi
- A cellophane tape is placed on the fungal culture and lifted
- The tape is then put on a slide with KOH or LPCB
- It's good for sampling sporulating fungi but may not show hyphae or rhizoids
- Advantage: does not destroy the morphology of fungi
- Disadvantage: limited to sampling reproductive spores and not vegetative spores
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the fascinating world of fungi, focusing on molds and their growth conditions. Learn about dimorphism, the difference between fungal and bacterial cultures, and the significance of environmental factors in fungal growth. This quiz is ideal for students of microbiology and mycology.
