FUNGI Flashcards
(86 cards)
1
Q
What type of organisms are fungi?
A
Eukaryotes
2
Q
How long ago did fungi separate from other lineages?
A
About 500 million years ago
3
Q
How many species of fungi have been identified and classified?
A
Around 70,000 species
4
Q
What is the estimated total number of fungal species?
A
1.5 million species
5
Q
What is the sister group to animals?
A
Fungi
6
Q
What are the three forms fungi can take?
A
Unicellular, multicellular, or dimorphic
7
Q
What are the two distinct morphological stages of fungi?
A
Vegetative and reproductive
8
Q
What type of environment do fungi prefer?
A
Moist and slightly acidic environment
9
Q
Can fungi grow with or without light or oxygen?
A
Yes
10
Q
What types of heterotrophs are fungi?
A
Saprophytic, parasitic or symbiotic
11
Q
As of 2019, how many phyla of fungi are there?
A
9 phyla
12
Q
List the 5 main phyla of fungi.
A
- Chytridiomycota
- Zygomycota
- Ascomycota
- Basidiomycota
- Glomeromycota
13
Q
How many fungal species cause disease in humans and animals?
A
~400 species
14
Q
How many fungal species cause disease in plants?
A
Thousands
15
Q
What is the trend in fungal infections worldwide?
A
Increasing worldwide (growing public health threat)
16
Q
How many deaths were attributed to fungal infections annually in 2013?
A
2 million deaths
17
Q
What is the estimated number of deaths due to fungal infections in 2024?
A
3.8 million deaths
18
Q
What are some factors contributing to the increase in fungal infections?
A
- Immunosuppressed hosts (e.g. HIV & Cancer)
- Climate change
- Increased travel and trade
- Drug-resistant fungi
19
Q
What is the impact of fungal infections on human and animal health?
A
Extensive social and economic impact, including crop pathogens and ringworm
Fungal infections can affect agriculture and health, leading to significant consequences.
20
Q
What trend has been observed regarding the incidence of invasive fungal infections?
A
Increasing incidence
This increase is concerning due to its implications for health and treatment options.
21
Q
What can misdiagnosis of fungal infections lead to?
A
Severe life-threatening consequences
Accurate diagnosis is crucial for effective treatment.
22
Q
What list does the World Health Organization maintain regarding fungal pathogens?
A
List of fungal ‘priority pathogens’
This list helps prioritize research and treatment efforts.
23
Q
What recent addition has been made to the WHO neglected tropical disease list?
A
Deep mycoses
This highlights the growing recognition of fungal diseases.
24
Q
What disease emerged in the 1970s that caused significant biodiversity loss?
A
Chytridiomycosis in amphibians
This disease has led to the greatest disease-driven loss of biodiversity ever recorded.
25
What is white nose syndrome, and when was it identified?
A disease affecting bats caused by Pseudogymnascus destructans, identified in 2007
## Footnote
This syndrome has serious implications for bat populations and ecosystems.
26
What are the ways of classifying fungi that cause disease?
By type of infection and by growth form
## Footnote
This classification helps in understanding and treating fungal infections.
27
What is the growth form of filamentous fungi?
Multinucleate, branching hyphae forming a mycelium
## Footnote
This structure is characteristic of many pathogenic fungi.
28
What type of infections do Epidermophyton, Microsporum, Sporothrix, and Trichophyton cause?
Filamentous superficial mycoses
## Footnote
These fungi primarily affect the skin and hair.
29
What type of cells do yeasts grow as?
Ovoid or spherical single cells
## Footnote
Yeasts multiply by budding and division.
30
List some examples of deep mycoses.
* Aspergillus
* Blastomyces
* Candida
* Coccidioides
* Cryptococcus
* Histoplasma
## Footnote
These fungi can cause serious internal infections.
31
What are the types of infections based on their focus?
* Superficial → affects hair/skin
* Cutaneous → epidermis/hair/nails
* Subcutaneous → deeper tissue
* Systemic → internal organs
* Opportunistic → infect immunocompromised hosts
## Footnote
Understanding these types helps in diagnosing and treating infections.
32
What are the types of fungal disease?
Superficial, Cutaneous, Subcutaneous, Anatomic, Systemic, Opportunistic
## Footnote
These categories describe the classification of fungal diseases based on their location and impact on the body.
33
What is the location of superficial fungal diseases?
Colonise dead layers of tissue (hair/skin)
## Footnote
Superficial fungal infections primarily affect the outermost layers of the skin and hair.
34
What is the representative disease caused by Malassezia?
Pityriasis, Tinea versicolor
## Footnote
These conditions are characterized by changes in skin pigmentation.
35
What is the causative organism of Piedra?
Piedra hortae
## Footnote
Piedra is a fungal infection that affects the hair shaft.
36
What type of fungi is responsible for athlete's foot?
Trichophyton rubrum, T. mentagrophytes, Epidermophyton floccosum
## Footnote
These three fungi are the most common causes of athlete's foot.
37
What are the symptoms of athlete's foot?
Red, cracked, weeping and itchy skin between the toes
## Footnote
Symptoms are often exacerbated by moisture and heat from socks and shoes.
38
What is the primary characteristic of cutaneous fungi?
Fungal infection of keratinised tissues
## Footnote
This includes skin, nails, hair, fur, and claws.
39
What are the three types of preferred hosts for cutaneous fungi?
* Geophilic (soil)
* Anthrophilic (humans)
* Zoophilic (other animals)
## Footnote
Each species of cutaneous fungi has a specific type of host it prefers.
40
What is the causative organism of Sporotrichosis?
Sporothrix
## Footnote
Sporotrichosis is caused by a specific genus of fungi that can infect skin and subcutaneous tissues.
41
What are examples of systemic fungal diseases?
* Coccidiomycosis
* Histoplasmosis
* Blastomycosis
* Cryptococcosis
* Candidiasis
* Aspergillosis
## Footnote
These diseases affect internal organs and can be severe.
42
What is a common characteristic of Malassezia species?
Commonly linked with chronic infection, allergic response or endocrine disease
## Footnote
These yeast-like fungi are often associated with skin conditions.
43
What is the formation that occurs with Piedra?
Formation of dark nodules on hair shaft
## Footnote
This condition can weaken hair and is indicative of a fungal infection.
44
True or False: Athlete's foot is the most common dermatophyte infection.
True
## Footnote
Athlete's foot is frequently encountered, especially in communal settings like gyms.
45
Fill in the blank: The fungi responsible for ringworm include _______.
Tinea, Trichophyton, Microsporum, Epidermophyton
## Footnote
These fungi infect keratinized tissues, leading to ringworm.
46
What is the treatment challenge for athlete's foot?
All the fungi involved must be removed for successful treatment
## Footnote
This emphasizes the difficulty of treating dermatophyte infections effectively.
47
What is Chytridiomycosis?
A disease caused by chytrid fungus affecting frogs and other amphibians.
## Footnote
Chytridiomycosis is linked to significant declines in amphibian populations worldwide.
48
What are motile zoospores?
Flagellated spores that live in water.
## Footnote
Motile zoospores are a characteristic feature of chytrid fungi.
49
Which species of chytrid fungus is associated with frogs?
Batrachochytrium dendrobatidis (Bd).
## Footnote
Bd is known to cause significant mortality in frog populations.
50
Which species of chytrid fungus affects salamanders and newts?
Batrachochytrium salamandrivorans (Bsal).
## Footnote
Bsal has been linked to declines in salamander populations in Europe.
51
What type of tissue does chytrid fungus infect?
Keratinised tissue.
## Footnote
In adults, this primarily affects the skin, while tadpoles are less affected.
52
List some regions affected by Chytridiomycosis.
* Australia
* Caribbean
* North America
* Central America
* South America
* Africa
* Europe
## Footnote
Chytridiomycosis has a global distribution.
53
What are clinical signs of Chytridiomycosis?
* Fungus invades the skin
* Problems with respiration
* Regulation of body hydration
## Footnote
These signs can lead to severe health issues in amphibians.
54
How is Chytridiomycosis transmitted?
* Worldwide through trade in amphibians
* Pharmaceutical industry (toads for pregnancy testing)
* Food
* Pets
* Spread since the 1930s
* Original source probably South Africa (Xenopus laevis)
## Footnote
Trade and agriculture practices have facilitated the spread of this disease.
55
What are subcutaneous infections?
Infections that enter through wounds, common in rural and tropical regions.
## Footnote
These infections may occur due to injuries from thorny plants.
56
Give examples of organisms causing subcutaneous infections.
* Madurella mycetomatis
* Sporothrix schenckii
## Footnote
Sporothrix schenckii is often associated with thorn-related injuries and has zoonotic potential.
57
What are systemic infections?
Infections where inhaled spores reach the lungs, bloodstream, and vital organs.
## Footnote
These infections can be more severe and affect multiple body systems.
58
What does it mean if an organism is dimorphic?
It can switch between yeast and hyphal forms.
## Footnote
Dimorphism is a characteristic of certain fungi, affecting their pathogenicity.
59
What is Aspergillosis?
A disease caused by Aspergillus fumigatus, resulting from spore inhalation leading to lung damage and fungus balls.
## Footnote
Aspergillosis is a significant cause of morbidity in immunocompromised patients.
60
What is Candidiasis?
An infection caused by Candida albicans affecting mucosal surfaces, especially during immune suppression.
## Footnote
Candidiasis can lead to thrush in the mouth and vaginal infections.
61
What types of organisms can be affected by certain diseases?
Reptiles and birds
## Footnote
These organisms can be affected by conditions similar to those in mammals.
62
What does dimorphism refer to in fungi?
Change from hyphal (mycelial) to yeast form
## Footnote
Dimorphism is a type of growth form change in response to environmental conditions.
63
What are adhesion factors in the context of fungal virulence?
Protease enzymes and lipase enzymes
## Footnote
These enzymes help fungi adhere to host tissues.
64
Define phenotypic switching in fungi.
Switch from white cells to opaque cells for sexual reproduction
## Footnote
This process alters the physical characteristics of the yeast.
65
How many different proteases are involved in fungal virulence?
10 different proteases
## Footnote
These proteases have various functions including adhesion, escaping host immune cells, and nutrient acquisition.
66
What is the causative agent of Histoplasmosis?
Histoplasma Capsulatum
## Footnote
This fungus is associated with soil and bat or bird feces.
67
What are common symptoms of Histoplasmosis?
Fever, headache, muscle ache, dry cough
## Footnote
Symptoms can vary based on individual immune response.
68
What is the thermal dimorph of Histoplasma?
Changes from mycelial form at room temperature to yeast form at body temperature
## Footnote
This ability is crucial for the fungus's survival and pathogenicity.
69
What happens to strains of Histoplasma that cannot perform the dimorphic switch?
They are avirulent and do not cause infection
## Footnote
The ability to switch forms is essential for pathogenicity.
70
How does the yeast form of Histoplasma replicate?
Inside macrophages, then carried from lungs around the body
## Footnote
This replication strategy aids in systemic infection.
71
What is a significant treatment challenge for fungal infections?
Limited drug options and toxicity
## Footnote
Antifungal drugs can be toxic to both the fungus and the host.
72
What is Amphotericin B used for?
IV use, nephrotoxic
## Footnote
It is a potent antifungal but has significant side effects.
73
What is Nystatin used for?
Topical use
## Footnote
It is commonly used to treat superficial fungal infections.
74
What are the drug targets for antifungal treatments?
* Ergosterol (membrane component)
* Glucan (cell wall)
## Footnote
Targeting these components helps in disrupting fungal cell integrity.
75
True or False: Most people recover from Histoplasmosis without treatment.
True
## Footnote
However, immunocompromised individuals may experience severe illness.
76
Which animals are particularly susceptible to Histoplasma?
Cats, dogs, and horses
## Footnote
Horses can develop epizootic lymphangitis as a result.
77
What is the primary method of administration for the substance described?
Topically with pimaricin
## Footnote
It is too toxic for intravenous administration and cannot be absorbed by the digestive tract.
78
What are the four main classes of anti-fungal agents and their mechanisms?
* Polyenes - disrupt fungal cell membrane by binding to ergosterol
* Azoles - interrupt enzymatic synthesis of ergosterol
* Allylamines - inhibit fungal squalene, a precursor to ergosterol
* Echinocandins - cause cell lysis by disrupting glucan synthesis
## Footnote
These mechanisms target crucial components of fungal cells.
79
What respiratory issues can fungal spores cause?
Respiratory allergies such as asthma and allergic alveolitis
## Footnote
This occurs through contact with eyes or inhalation.
80
What are the short-term symptoms of immediate allergic response to fungal spores?
* Itchy eyes
* Running nose
* Sore throat
## Footnote
These symptoms occur due to short-term exposure.
81
What is mycetism?
Mushroom poisoning from eating toxic mushrooms
## Footnote
This occurs when consuming mushrooms that contain preformed toxic metabolites.
82
What are the toxins associated with Amanita phalloides and Amanita muscaria?
* Amatoxins from Amanita phalloides
* Botulinic acid from Amanita muscaria
## Footnote
These toxins are responsible for severe poisoning cases.
83
What is mycotoxicosis?
Eating fungi that have produced toxins while growing on food
## Footnote
This condition is dangerous to health, especially affecting the liver.
84
What is the concern regarding aflatoxin in foods?
Detection of aflatoxin in foods can be lethal
## Footnote
The lethal dose for humans is 10-20 mg.
85
Fill in the blank: Polyenes disrupt fungal cell membranes by binding to _______.
ergosterol
## Footnote
Ergosterol is a crucial component of fungal cell membranes.
86
True or False: Allylamines interrupt the synthesis of glucan in fungal cells.
False
## Footnote
Allylamines inhibit squalene, while echinocandins disrupt glucan synthesis.
