Presentation on theme: "Head, Development and Quality Assurance Unit"— Presentation transcript:
1Head, Development and Quality Assurance Unit Kingdom FungiDr. ROD ALFONSOHead, Development and Quality Assurance Unit
2Requirements to get Good Grade Perfect AttendanceParticipate actively in classroom activitiesPass assignment on timePass all quizzes and major examsGood attitude
3Learning ObjectivesAt the end of the lesson, students will be able to:Define mycology; Define a fungusDescribe the characteristics of fungiDescribe the distribution of fungi in natureExplain why there are few invasive fungal infection.Describe the characteristics of yeasts and how they reproduceDiscuss the significance of yeast in food industry, in medicine and biofuel industry.Describe moldsDifferentiate hypha, thallus and myceliumDifferentiate between septate and coenocytic hyphaeExplain dimorphic fungiDiscuss the beneficial and harmful effects of fungi
4MycologyMycology is the study of fungi ( yeasts, molds and mushrooms)
5001001. Five kingdom system of classifying living things showing that both fungi and animals may have evolved from a common ancestor.
6What is a fungus?A eukaryotic, heterotrophic organism devoid of chlorophyll that obtains its nutrients by absorption, and reproduces by spores.The primary carbohydrate storage product of fungi is glycogen.Most fungi have a thallus composed of hyphae (sing. hypha) that elongate by tip growth
7The Characteristics of Fungi Eukaryotic(true nucleus)Larger, more complex than bacteriaLack chlorophyllChitin, glucan & mannan are the complex carbohydrates found in their cell wallReproduce sexually and asexuallyCell wall contains ergosterolHeterotrophic (require organic carbon)
8Fungal Fast Facts Fungi are all around us We touch them, we swallow them, we breathe themThere are more than 1.5 million fungal species in natureYet only about 100 cause human diseaseMost cause superficial infections, some cause allergic reactionsFew cause invasive infections
9Host/Pathogen Balance: Normal Circumstances Why so few Invasive Infections?Host/Pathogen Balance: Normal CircumstancesFungal FactorsAnatomicalbarriersVirulenceHost FactorsAdaptive immunityFungal BurdenInnate defensesInfectionProtection
10Yeast - Major Characteristics Unicellular Fungi, nonfilamentous, oval or spherical cellsEukaryoticFacultative anaerobesWhen oxygen is available, they carry out aerobic respiration.When oxygen is not available, they ferment carbohydrates to produce ethanol and carbon dioxide.Capable of forming colonies on solid culture media (see pictures on the right).
11Yeast - ReproductionThey reproduce either asexually (most common) or sexually.Asexual reproduction is through budding or binary fission.Sexual reproduction (if any) results in the formation of the appropriate spore structure.FissionSporesBuddingSaccharomyces cerevisiaeSchizosaccharomyces octosporus
12Yeast Significance Medical Biofuel Industry Food Industry Fermentation of bread, beer, and wine. E.g. Saccharomyces cerevisiae (also called baker’s yeast or sugar yeast) used in baking and fermenting of alcoholic beverages.MedicalE.g. Candida albicans - common in the human mouth, but can become pathogenic and cause Candidiasis (oral and/or genital infection).Biofuel IndustryProduction of ethanol for car fuel.
13Multicellular, filamentous fungi. 2. Molds and Fleshy FungiMulticellular, filamentous fungi.Identified by physical appearance, colony characteristics, and reproductive spores.Thallus: Body of a mold or fleshy fungus. Consists of many hyphae.Hyphae (Sing: Hypha): Long filaments of cells joined together.Septate hyphae: Cells are divided by cross-walls (septa).Coenocytic (Aseptate) hyphae: Long, continuous cells that are not divided by septa.Hyphae grow by elongating at the tips.Each part of a hypha is capable of growth.Vegetative Hypha: Portion that obtains nutrients.Reproductive or Aerial Hypha: Portion connected with reproduction.Mycelium: Large, visible, filamentous mass made up of many hyphae.
14Characteristics of Fungal Hyphae: Septate versus Coenocytic
15Hyphae Tubular Hard wall of chitin Crosswalls may form compartments (± cells)MultinucleateGrow at tipsChitin is the same material used by Arthropods (Insects, crabs, etc.) in their exoskeletonsaNuclei of fungi are hard to see without stains
16Hyphal growth Hyphae grow from their tips Mycelium = extensive, feeding web of hyphaeMycelia are the ecologically active bodies of fungiThis wall is rigidOnly the tip wall is plastic and stretches
18Dimorphic FungiCan exist as both multicellular fungi (molds) and yeasts.Many pathogenic species.Mold form produces aerial and vegetative hyphae.Yeast form reproduces by budding.Dimorphism in pathogenic fungi typically depends on temperature:At 37oC: Yeast form.At 25oC: Mold form.Dimorphism in nonpathogenic fungi may depend on other factors: Carbon dioxide concentration.Yeast at 370CMold at 250C
19HUMAN-FUNGUS INTERACTIONS Beneficial Effects of FungiDecomposition - nutrient and carbon recycling.Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e.g., fermented products, mushrooms).Model organisms for biochemical and genetic studies.Harmful Effects of FungiDestruction of food, lumber, paper, and cloth.Animal and human diseases, including allergies.Toxins produced by poisonous mushrooms and within food (e.g., grain, cheese, etc.).Plant diseases.