MLS 474 (Clinical Mycology) MLS 474 (Clinical Mycology) – To reveal sufficient To reveal sufficient basic basic science science of the medically of the medically important fungi to assist important fungi to assist you in diagnosing mycotic you in diagnosing mycotic diseases. diseases. – To reveal sufficient To reveal sufficient clinical knowledge clinical knowledge to to raise your index of raise your index of suspicion for mycotic suspicion for mycotic OBJECTIVES OBJECTIVES
29
Embed
MLS 474 (Clinical Mycology) –To reveal sufficient basic science of the medically important fungi to assist you in diagnosing mycotic diseases. –To reveal.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
– To reveal sufficient To reveal sufficient basic basic sciencescience of the medically of the medically important fungi to assist you in important fungi to assist you in diagnosing mycotic diseases.diagnosing mycotic diseases.
– To reveal sufficient To reveal sufficient clinical clinical knowledgeknowledge to raise your index to raise your index of suspicion for mycotic of suspicion for mycotic diseases. diseases.
OBJECTIVESOBJECTIVES
Introduction to medical mycologyIntroduction to medical mycology Fungal classification and TaxonomyFungal classification and Taxonomy Antifungal Therapeutic AgentsAntifungal Therapeutic Agents Superficial MycosesSuperficial Mycoses Cutaneous Mycoses Cutaneous Mycoses Subcutaneous MycosesSubcutaneous Mycoses Systemic Mycoses Systemic Mycoses Fungal AllergiesFungal Allergies Mushroom Poisoning and other Mushroom Poisoning and other MycotoxinsMycotoxins
TopicsTopics
INTRODUCTIONINTRODUCTION
the study of fungi, includes their genetic the study of fungi, includes their genetic and biochemical properties, their and biochemical properties, their taxonomy, and their use to humans as taxonomy, and their use to humans as source for medicinals (e.g., penicillin), source for medicinals (e.g., penicillin), food (e.g., beer, wine, cheese, edible food (e.g., beer, wine, cheese, edible mushrooms), as well as their dangers, mushrooms), as well as their dangers, such as poisoning or infection.such as poisoning or infection.
What is What is MycologyMycology??
MYCOLOGY is the study of fungi Myco- = fungi -ology = the study of
Kingdom FungiKingdom Fungi
The characteristics of fungiThe characteristics of fungi Fungal classificationFungal classification Fungal life cyclesFungal life cycles
The Characteristics of The Characteristics of FungiFungi Body form Body form
like strands called like strands called hypha (singular) or hypha (singular) or hyphae (plural) hyphae (plural)
– mycelium = mycelium = aggregate of aggregate of hyphae hyphae
– sclerotium = sclerotium = hardened mass of hardened mass of mycelium that mycelium that generally serves as generally serves as an overwintering an overwintering stage. stage.
– fruit bodies fruit bodies (mushrooms) (mushrooms)
TubularTubular Hard wall of chitinHard wall of chitin Crosswalls may Crosswalls may
form compartments form compartments ((± ± cells)cells)
MultinucleateMultinucleate Grow at tipsGrow at tips
HyphaeHyphae
Hyphal growthHyphal growth Hyphae grow from their tipsHyphae grow from their tips Mycelium = extensive, feeding web of Mycelium = extensive, feeding web of
hyphaehyphae Mycelia are the ecologically active Mycelia are the ecologically active
bodies of fungibodies of fungi
This wall is rigid Only the tip wall is plastic and stretches
Mode of nutritionMode of nutrition
Fungi get carbon from organic sourcesFungi get carbon from organic sources Hyphal tips release enzymesHyphal tips release enzymes Enzymatic breakdown of substrateEnzymatic breakdown of substrate Products diffuse back into hyphaeProducts diffuse back into hyphae
–Parasites :Parasites : feeding on living tissue of a feeding on living tissue of a host.host. Parasites that cause disease are Parasites that cause disease are called pathogens. called pathogens.
Fungi as Parasites –PathogensFungi as Parasites –Pathogens..
Fungi are Spore-ificFungi are Spore-ific!!!!!!
Spores - asexual (product of Spores - asexual (product of mitosis) or sexual (product mitosis) or sexual (product of meiosis) in origin. of meiosis) in origin.
Purpose of Spores Purpose of Spores – Allows the fungus to Allows the fungus to
move to new food source. move to new food source. – Resistant stage - allows Resistant stage - allows
fungus to survive periods fungus to survive periods of adversity.of adversity.
– Means of introducing new Means of introducing new genetic combinations into genetic combinations into a populationa population
Reproduce by sporesReproduce by spores Spores are reproductive cellsSpores are reproductive cells
– Sexual (meiotic in origin)Sexual (meiotic in origin)– Asexual (mitotic in origin)Asexual (mitotic in origin)
Formed:Formed:– Directly on hyphaeDirectly on hyphae– Inside sporangiaInside sporangia– Fruiting bodies Fruiting bodies
Amanita fruiting body
Pilobolus sporangia
Penicillium hyphae with
conidia
Hyphal growth from sporeHyphal growth from spore
myceliumgerminatingspore
Mycelia have a huge surface areaMycelia have a huge surface area
Generalized Life Cycle of a Generalized Life Cycle of a FungusFungus
Definitions and Fungal Definitions and Fungal TerminologyTerminology
CLINICAL MYCOLOGY:CLINICAL MYCOLOGY: Remains more of a descriptive art than an analytical science.Remains more of a descriptive art than an analytical science.
Mold (sometimes spelled ‘mould’): is a morphological term referring to a filamentous (multicellular) fungus.
Yeast is a morphological term referring to a unicellular fungus.
DIMORPHIC FUNGI: This class of fungi is characterized by two forms of growth:1. Growth as a mold with septate hyphae in their natural reservoir (e.g. soil) or when incubated at 25° C. on conventional fungal media (Sabouraud dextrose or potato dextrose agars).2. Growth as a yeast in the tissues of an animal/person or when incubated at 37° on enriched media (Brain heart infusion agar).
A hypha (plural hyphae) is a long, branching filamentous cell. hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Mycelium: the intertwined mass of hyphae that forms the mold colony. The vegetative mycelium is composed of those hyphae that adhere to the substrate and absorbs nutrients. The aerial mycelium is composed of those hyphae that grow up from the surface and support the spores.
Septate: Cross-walls (septae) that divide hyphae into segments. If there are few or no cross-walls the hyphae are considered to be aseptate.
Conidia (singular = conidium): asexual spores borne externally on hyphae or on a conidiophore.
Conidiophore: the specialized hyphal stalk on which conidia develop either singly or in Clusters.
Conidia
Conidiophore
Sporangia (singular = sporangium): spherical sack within which asexual spores (sporangiospores) form by progressive cytoplasmic cleavage.
Sporangiophore - specialized hyphal stalk which bears sporangia.
Sporangiospores: small spores contained within sporangia.
Sporangiospores
Sporangium
Sporangiophore
Rhizoid: rootlike branched hyphae which anchor the mycelium to the substrate; characteristic of certain Zygomycetes (Rhizopus and Absidium).
Dematiaceous Molds: the term dematiaceous refers to molds whose hyphae are pigmented. Because of the pigment, the colonies of these fungi will appear dark green, brown, or black on both the top and reverse (underside).
Germ-tube: The initial hyphal outgrowth of a germinating spore or yeast; especially important for identification of Candida albicans.
Pseudohyphae (or Pseudomycelium): chains of successively budding yeast cells that have complete cell walls, but have not detached from one another.