Microbiology Chapter 17.txt

  1. Molds
    Molds grow as long, tangled filaments of cells in visible colonies
  2. Yeasts
    Yeasts are unicellular fungi
  3. Hypha
    Most fungi (except yeasts) exist as hyphae
  4. Mycelium
    A mycelium is a thick mass of hyphae
  5. Fungus Cell wall
    • Cellulose
    • Chitin
    • Fungal cell walls are composed of chitin
  6. Septa
    In many species, septa divide the cytoplasm into separate cells
  7. Dimorphic
    Growing at filamentous molds or as unicellular pathogens
  8. Heterotrophic
    • Eat food
    • Fungi absorb preformed organic matter so they are called heterotrophs
  9. Saprophytic
    Feeding on dead or decaying organic matter
  10. Parasitic
    Live on skin
  11. Coenocytic
    Hyphae containing many nuclei are considered coenocytic
  12. Growth of the Fungi
    • Most fungi are aerobic
    • Most fungi grow best at around room temperature
  13. Fungi Temperature
    • 20-25C - Slow growth, mold like appearance.
    • 37C - Colony form, yeast like
  14. Biphasic (dimorphic)
    • Different shapes at different temps
    • Some fungal species may actually have both a mold and yeast life cycle stage
    • This ability is largely determined by temperature, but it is also influenced by other factors such as levels of oxygen and nutrients.
    • True fungal pathogens to humans are dimorphic.
  15. Fungi pH
    Many fungi thrive at slightly acidic pH (pH 5-6)
  16. Fungi growth medium
    Sabouraud Dextrose Agar
  17. Fungal Growth Is Influenced by Several Factors
    Fungi take up nutrients through absorption
  18. Asexual reproduction Reproduction in Fungi
    • No genetic diversity
    • Sporangiospores
    • Conidiaspores
    • Arthrospores
    • Blastospores
    • Chlamydiospores
  19. Sexual reproduction
    • Genetic diversity
    • Fusion of cells/hyphae
    • Heterokaryon
    • Fusion of nuclei
    • Zygote
    • Meiosis
    • Spore-producing structure
    • Spores
    • Germination
  20. Fruiting bodies
    Sporulation occurs in fruiting bodies
  21. Asexual reproductive structures
    • Asexual reproductive structures develop at the ends of specialized hyphae
    • Many asexual spores (sporangiospores) develop in sacs called sporangia
  22. Conidiophores
    • Penicillium and Aspergillus possessing septate hyphae and produce conidia (asexual spores) at the end of aerial hyphae called conidiophores
    • Conidia form as unprotected spores on conidiophores
  23. Sporangiospore
    • Sporangiospores develop in sacs called sporangia
    • The sporangia located at the end of aerial hyphae are called sporangiophores.
    • Rhizopus has nonseptate hyphae and produce asexual sporangiospores within a sac called the sporangium.
  24. Macroconidia
    Large spores
  25. Arthrospore
    • Fragmentation of hyphae yields arthrospores
    • The ends get thick and break off
    • Athlete's foot
  26. Budding
    • In budding, a blastospore develops from the parent cell
    • Yeast
  27. Fungi can also reproduce sexually
    Opposite mating types come together and fuse into a heterokaryon
  28. Fungi Classification
    • Division I: Eumycota
    • Class 2: Zygomycetes
    • Class 3: Ascomycetes
    • Class 5: Deuteromycetes
  29. Zygomycetes
    • Form a zygospore
    • Zygomycetes are terrestrial fungi that grow as mold on bread and produce
    • In asexual reproduction, they produce a sporangiaspores
    • During sexual reproduction, they form a heterokaryotic, diploid zygospore
  30. Ascomycetes
    • Conidia through asexual reproduction
    • Ascospores through sexual reproduction
  31. Ascomycetes account for 75% of known fungi, including:
    • Baker�s yeast
    • The mold that produces penicillin
    • The fungus that produces aflatoxin
    • Candida albicans, the cause of thrush, diaper rash, and vaginitis
  32. Basidiomycetes
    • Basidiomycetes are club fungi, including mushrooms and puffballs
    • Some form mycorrhizae
    • Others are plant pathogens
    • Basidia on the gills of a mushroom cap contain sexually-produced basidiospores
  33. Deuteromycetes
    • No known sexual reproduction
    • Imperfect fungi
  34. Saccharomyces cerevisiae
    • Produces CO2 or alcohol
    • Reproduces by budding
    • Has lots of B vitamins
  35. Saccharomyces ellipsoideus
    • In orchards
    • Wine yeasat
  36. Yeasts Represent a Term for
    Any Single-Celled Stage of a Fungus
  37. Saccharomyces is a fungus that can
    Ferment sugars
  38. Saccharomyces is used in
    • They are used in bread backing and alcohol production
    • S. cerevisiae is a model eukaryotic organism
  39. Dermatomycosis
    Moldy skin
  40. T. pedis
  41. T. capitis
  42. T. corporis
  43. T. crucis
  44. T. unguium
  45. T. favosa (barber)
    Haired portion of the head and face
  46. Dermatophytosis
    A fungal infection of the body surface
  47. Dermatomycosis Symptoms
    Include blister-like lesions with a thin fluid discharge
  48. Dermatomycosis Treatment
    • Often involves changing the skin environment (moisture, pH, etc.)
    • Keep skin dry
    • Vinegar & Honey
    • Cigar Ash
  49. Species called dermatophytes cause
    dermatophytosis (tinea infections/ringworm) on the skin, hair, nails
  50. Dermatophytes can be transmitted by contact with
    • Domestic animals
    • Fomites like:
    • floors
    • mats
    • towels
  51. Dermatomycosis fungi
    • Tricophyton
    • Microsporium
    • Epidermophyton
  52. Dermatomycosis Id reaction
    • An immune reaction showing symptoms of fungal infection elsewhere on the body.
    • When the sight is cultured, there is no fungus there.
  53. Candidiasis
    • 33% in the US have this on their skin
    • Candidiasis Often Is a Mild, Superficial Infection
  54. Candida albicans can cause candidiasis when:
    • The immune system is compromised or
    • Microbial populations in the body change
  55. Vulvovaginitis,
    • Often called a �yeast infection,� involves
    • itching
    • burning
    • reddening
    • swelling
    • Discharge
  56. Excessive antibiotic use may
    Decrease protective bacteria in the vagina and intestine, allowing C. albicans to flourish
  57. Candida albicans infections
    • Vulvovaginitis (yeast infection)
    • Oral candidiasis (thrush)
    • Onychia, a brownish thickening of the nails
  58. Candida Treatment
    • Gentian violet
    • Nystatin
  59. Sporotrichosis
    • Sporothrix schenkii
    • Rose thorn disease
    • Infection with spores can cause pus-filled lesions
    • Get when immune system isn't working
  60. Sporotrichosis can occur in people who work with
    • Sporotrichosis Is an Occupational Hazard
    • wood
    • wood products
    • soil
  61. Sporotrichosis Transmission
    • Poked with a rose thorn
    • Peat moss
    • Splinters
  62. Sporotrichosis Treatment
    Amphotericin B
  63. Cryptococcus neoformans
    • Found in pigeon droppings
    • Affects lungs and meninges
    • Commonly seen in AIDS patients
    • Cells can (rarely) pass into the bloodstream, infecting the brain and meninges
  64. Cryptococcus neoformans Symptoms
    • Headache
    • Stiff neck
    • Possible paralysis
  65. Cryptococcus neoformans Treatment
    Amphotericin B
  66. Amphotericin B side effects
    Damages kidneys
  67. Histoplasmosis
    • It is caused by Histoplasma capsulatum
    • It is found in dry, dusty soil, chicken coops, and bat caves
    • Most people suffer only mild influenza-like symptoms
    • Darling�s disease
  68. Histoplasmosis Transmission
    Inhaling dust
  69. Histoplasmosis Symptoms
    • Summer flu
    • Occasionally nodules in the lungs
    • Looks just like TB in XRay
  70. Histoplasmosis Treatment
    If nodules in the lungs, Amphotericin B, otherwise clears without help
  71. Blastomycosis
    • It is caused by Blastomyces dermatitidis
    • Gilchrist�s disease
  72. Blastomycosis Transmission
    • Blastomycosis Usually Is Acquired Via the Respiratory Route
    • It is associated with dusty soil and bird droppings
  73. Blastomycosis Inhalation Symptoms
    • Lung lesions
    • Persistent cough
    • Chest pains
    • It can cause chronic pneumonia and may disseminate to other organs in AIDS patients
  74. Blastomycosis Treatment
    Amphotericin B
  75. Aspergillosis
    • It is commonly caused by Aspergillus fumigatus
    • In aspergillosis, conidia enter the body and grow as a mycelium
  76. Aspergillosis Treatment
    Surgery may be necessary to remove an aspergilloma from the lungs
  77. Aspergillus can also cause
    Otomycosis in the ear, which can affect the heart
  78. Aspergillus niger is used in
    Beano� to reduce flatulence
  79. Aspergillosis Transmission
    Inhaling a spore
  80. Aspergillosis Treatment
    Amphotericin B
  81. Aspergillosis Diseases
    • Aspergilloma
    • Otomycosis
  82. Fungal Toxins
    • Aflatoxin: Aspergillus flavus
    • Mycotoxins
    • A. flavus and A. parasiticus produce carcinogenic aflatoxins
    • Aflatoxins contaminate many agricultural products
    • Can eat through the skin
  83. Ergotism
    Ergotism is caused by Claviceps purpurea, which grows on Rye, Wheat, Barley
  84. Ergotism Transmission
  85. Ergotism Symptoms
    • numbness
    • hot and cold sensations
    • seizures
    • paralysis of nerve endings
  86. Ergot Uses
    • Pitosin
    • Lysergic acid diethylamide (LSD) is a derivative of an alkaloid in ergot
  87. Lichens are a
    mutualistic association between a fungus (frequently an ascomycete) and a photosynthetic organism
  88. Pneumocystis Pneumonia Can Cause a Lethal Pneumonia
    • It is caused by Pneumocystis jiroveci
    • It is a common infection in AIDS patients
    • P. jiroveci has a complex life cycle in the alveoli
    • It is usually transmitted through respiratory droplets
  89. Mold
    Fungi that grow as long, tangled filaments of cells that give rise to visible colonies.
  90. Hypha
    • Intertwined filaments of mold.
    • The morphological (structural) unit of filamentous fungi
  91. Mycelium
    • A thick mass of hyphae
    • Usually large enough to be seen with the unaided eye and generally has a rough, couttony texture.
  92. Chitin
    • A carbohydrate polymer of actylglucosamine units
    • Composes a large amount of the cell wall
  93. Septum
    Walls that separate the hyphal cytoplasm into separate cells
  94. Coenocytic
    Hyphae contains many nuclei in a common cytoplasm
  95. Dimorphic
    Fungi that grow as filamentous molds at room temperature (25C) and convert to unicellular, pathogenic yeast-like forms at body temperature (37C)
  96. Potato dextrose agar or Sabouraud dextrose agar
    Laboratory media containing extra glucose for growing molds and yeasts
  97. Mutualism
    A symbiotic relationship between two organisms of different species that benefits both.
  98. Mychorrhizal fungi
    • Live harmoniously with plants where the hyphae invade or envelop the roots of plants.
    • They consume some of the carbs produced by the plants
    • Contribute essential minerals and water to the plants
  99. Fruiting body
    Part of the fungus where spores are formed and from which they are released.
  100. Sporangiospore
    Spores produced in sacs called sporangia
  101. Conidium
    Spores produced on the supportive structures called conidia. These spores are unprotected, are very light and blown on wind currents.
  102. Arthrospore
    • Spores that form by fragmentation of the hyphae.
    • Athlete's foot fungus multiplies in this manner
  103. Blastospore
    A new yeast cell formed by budding.
  104. Heterokaryon
    • Fungi produced by sexual reproduction
    • The nuclei are different from each parent
    • Hetero = different
    • Karyo = nucleus
  105. Chytrid
    The oldest known fungi belonging to the phylum Chytridiomycota
  106. Zygospore
    • Formed during sexual reproduction between Zygomycota.
    • Opposites fuse forming a unique, heterokaryotic, diploid zygospore
  107. Lichen
    A member ascomycota phylum, lichen is a mutualistic association between a fungus and a photosynthetic organism.
  108. Basidiocarp
    Club fungi members of the Basidiomycota phylum
  109. Thrush
    Oral candidiasis
  110. Trophozoite
    The feeding stage of Pneumocytstis jiroveci swells to become a precyst stage
  111. Mycotoxin
    Toxins produced my fungi
Card Set
Microbiology Chapter 17.txt
Microbiology Chapter 17