Mushrooms Club Like Fungi or Basidiomycete Fungi others
Mushrooms – “Club Like” Fungi or Basidiomycete Fungi others are extremely toxic and may cause permanent liver & brain damage or death if ingested
Yeasts: Good source of Vitamins and Proteins Used in baking industry Used in making beer & wine Aspergillus oryzae is used to make soy sauce Penicillium camemberti is used in making blue cheese
Molds are used to prepare antibiotics like penicillin and cephalosporine
Molds u. Some types produce immunosuppressants like cyclosporine u. Some molds are used to produce enzymes such as amylase, citric acid. u. Give the flavor of some types of cheeses
BIOLOGICAL CONTROL
Mycorrhizae means “fungus-root”; mutualistic relationship between plant and fungi The plant photosynthesizes while the fungus more efficiently takes up nutrients and water from the rhizosphere than the roots would alone. Plant benefits include: • Improved nutrient/water uptake • Improved root growth • Improved plant growth and yield • Improved disease resistance • Reduced transplant shock
Harmful Fungus n Fungus can cause things such as: u. Mold on food u. Athlete's Foot u. Dandruff
– Poisonous Fungi Amanita mushroom is highly poisonous Alkaloids of Claviceps purpurea cause food poisoning Also produce L. S. D. Aspergillus produce Aflatoxins –which cause food poisoning & are highly carcinogenic
Morels and Truffels are edible Fungi
The Characteristics of Fungi n Body form u unicellular u filamentous (tube-like strands called hypha) u mycelium = aggregate of hyphae u sclerotium = hardened mass of mycelium Note: They flourish in moist and dark places.
Hyphae n Tubular n Hard wall of chitin n Crosswalls may form compartments (± cells) n Multinucleate n Grow at tips
Heterotrophic : Saprobes, Symbionts, Parasite n n n Hyphal tips release enzymes Enzymatic breakdown of substrate Products diffuse back into hyphae Nucleus hangs back and “directs” Product diffuses back into hypha and is used
Deuteromycota – the Fungi Imperfecti n Resemble Ascomycetes, but their reproductive Penicillium fungi cycle has never been observed n Different from Ascomycetes because there is a definite lack of sexual reproduction, which is why they are called Imperfect Fungi Up Close
Fruticose Crustose Foliose
Lichens are mutualistic symbiotic organisms. In lichens, algae and fungi live together symbiotically. Lichens are useful in making : Dyes Medicines Religious ceremonies
Opportunistic Infection by Candida albicans in an AIDS Patient Source: Atlas of Clinical Oral Pathology, 1999
Severe nail infection with Trichophyton rubrum in a 37 -year-old male AIDS patient. Source: Intern. J. Dermatol. 31(1992): 453.
Disseminated Histoplasma capsulatum, skin infection. Source: Microbiology Perspectives, 1999.
Severe nail infection with Trichophyton rubrum in a 37 -year-old male AIDS patient. Source: Intern. J. Dermatol. 31(1992): 453.
Systemic Mycosis: Histoplasmosis Disseminated Histoplasma capsulatum, lung infection. Source: Microbiology Perspectives, 1999.
Cutaneous Mycosis Candida albicans infection of the nails. Source: Microbiology Perspectives, 1999.
Cutaneous Mycosis Ringworm skin infection: Tinea corporis Source: Microbiology Perspectives, 1999
Other Basidiomycetes Rusts and Smuts Rust infecting wheat leaves Rust infecting a Leaf Whitrot Smut digesting old wood
Irish Potato Famine of 19 th Century Devastated potato crops, causing devastating starvation in Ireland
Cup Fungi – Ascomycete Fungi Note the cup shapes and orange peel colour
Bread Mold – a Zygomycete Fungi
HUMAN-FUNGUS INTERACTIONS n n Beneficial Effects of Fungi u Decomposition - nutrient and carbon recycling. u Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e. g. , fermented products, mushrooms). u Model organisms for biochemical and genetic studies. Harmful Effects of Fungi u Destruction of food, paper, and cloth. u Animal and human diseases, including allergies. u Toxins produced by poisonous mushrooms and within food (e. g. , grain, cheese, etc. ). u Plant diseases.
FUNGAL DISEASES Mycosis: Any fungal disease. Tend to be chronic because fungi grow slowly. Mycoses are classified into the following categories: I. Systemic mycoses: Fungal infections deep within the body. Can affect a number if tissues and organs. u Usually caused by fungi that live in the soil and are inhaled. Not contagious. u Examples: u Histoplasmosis (Histoplasma capsulatum): Initial infection in lungs. Later spreads through blood to most organs. u Coccidiomycosis (Coccidioides immites): Resembles tuberculosis.
HUMAN-FUNGUS INTERACTIONS n n Beneficial Effects of Fungi u Decomposition - nutrient and carbon recycling. u Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e. g. , fermented products, mushrooms). u Model organisms for biochemical and genetic studies. Harmful Effects of Fungi u Destruction of food, paper, and cloth. u Animal and human diseases, including allergies. u Toxins produced by poisonous mushrooms and within food (e. g. , grain, cheese, etc. ). u Plant diseases.
FUNGAL DISEASES (Continued) II. Cutaneous mycoses: Fungal infections of the skin, hair, and nails. u Secrete keratinase, an enzyme that degrades keratin. u Infection is transmitted by direct contact or contact with infected hair (hair salon) or cells (nail files, shower floors). u Examples: u Ringworm (Tinea capitis and T. corporis) u Athlete’s foot (Tinea pedis) u Jock itch (Tinea cruris)
FUNGAL DISEASES (Continued) III. Subcutaneous mycoses: Fungal infections beneath the skin. u Caused by saprophytic fungi that live in soil or on vegetation. u Infection occurs by implantation of spores or mycelial fragments into a skin wound. u Can spread to lymph vessels. IV. Superficial mycoses: Infections of hair shafts and superficial epidermal cells. Prevalent in tropical climates.
FUNGAL DISEASES (Continued) Opportunistic mycoses: Caused by organisms that are generally harmless unless individual has weakened defenses: u u AIDS and cancer patients u Individuals treated with broad spectrum antibiotics u Very old or very young individuals (newborns). Examples: u Aspergillosis: Inhalation of Aspergillus spores. u Yeast Infections or Candidiasis: Caused mainly by Candida albicans. Part of normal mouth, esophagus, and vaginal flora.
ECONOMIC IMPORTANCE OF FUNGI u 25 -50% of harvested fruits and vegetables are damaged by fungi. u Fungal infections of plants are commonly called rots, rusts, blights, wilts, and smuts. u u Phytophthora infestans: Caused great potato famine in mid-1800 s. Over 1 million people died from starvation in Ireland. Many immigrated to the U. S. Beneficial fungi: u Candida oleophila: Prevents fungal growth on harvested fruits. u Saccharomyces cerevisiae: Used to make bread and wine. u Genetically engineered yeast strains are used to make proteins (Hepatitis B vaccine). u Taxomyces: Produces anticancer drug taxol. u Trichoderma: Produces cellulase. Used to make fruit juice.
u III. LICHENS u Combination of a green alga (or cyanobacterium) and a fungus. u Mutualistic relationship in which each partner benefits. u Alga: Provides nutrients by photosynthesis to fungus. u Fungus: Provides attachment and protection from desiccation. u 20, 000 species of lichens occupy unique habitats, in which either fungi or algae could not survive alone: rocks, cement, rooftops, trees, and newly exposed soil. u Grow very slowly, secreting acids that break down rocks. u Accumulate nutrients needed for plant growth. u Sensitive to air pollution. u Major food source for tundra herbivores (caribou and reindeer).
Lichens: Combinations of Fungi and Green Algae (or Cyanobacterium)
u Medically Important Protozoa u u u 1. Amoeboflagellates (Phylum Sarcomastigophora) Move using pseudopods (false feet) or flagella. A. Amoebas (Subphylum Sarcodina) Move by extending blunt, lobelike projections (pseudopods). Amoebas engulf food with pseudopods and phagocytize it. Several species cause amoebic dysenteries of varying degrees of severity. u u u Entamoeba hystolytica: Feeds on red blood cells. Produces dysentery and extraintestinal cysts. Dientamoeba fragilis: Found in 4% of humans. Usually commensal. Can cause chronic, mild diarrhea. Other diseases include: u u Meningoencephalitis: Caused by Naegleria fowleri. Penetrate nasal mucosa of swimmers in warm waters. Mortality rate almost 100%. Keratitis: Caused by Acanthamoeba. Can cause blindness. Associated with use of contact lenses.
u u u B. Flagellates (Subphylum Mastigophora) Move by one or more whiplike flagella. Some parasitic flagellates have up to eight flagella. Most are spindle shaped with flagella projecting from anterior end. Outer membrane is a tough pellicle. Food is ingested through an oral groove or cytosotome. Important pathogens: u u Trichomonas vaginalis: Causes genital and urinary infections. Has undulating membrane. Lacks a cyst stage. Transmitted sexually or by fomites. Giardia lamblia: Causes a persistent intestinal infection (giardiasis) with diarrhea, nausea, flatulence, and cramps. In U. S. most common cause of waterborne diarrhea. About 7% of U. S. population are healthy carriers. Trypanosoma brucei gambiense: Hemoflagellate (blood parasite). Causes African sleeping sickness. Trypanosoma cruzi: Hemoflagellate that causes Chaga’s disease, a cardiovascular disease common in Texas and Latin America.
Medically Important Protozoa (Continued) 2. Apicomplexans (Phylum Apicomplexa) u Not motile in their mature form. u Obligate intracellular parasites. u Have specialized organelles at tip (apex) of cells that penetrate host tissues. u Complex life cycles. May have more than one host. Definitive host: Harbors sexually reproducing form. Intermediate host: In which asexual reproduction occurs.
u Medically Important Protozoa (Continued) u u 2. Apicomplexans (Phylum Apicomplexa) Important pathogens: u Plasmodium vivax and falciparum: Cause malaria in humans (intermediate host). Initially treated with quinine, drug resistance is a major problem today. Major cause of worldwide mortality: Kill 3 million people/year and infect 500 million. Transmitted by Anopheles mosquito (definitive host). DDT was used extensively in 1960 s in an attempt to eradicate the mosquito vector. Successful vaccine not available yet.
Life Cycle of Plasmodium spp. the Infectious Agent of Malaria
u Medically Important Protozoa (Continued) u u 2. Apicomplexans (Phylum Apicomplexa) Important pathogens: u Toxoplasma gondii: Causes toxoplasmosis in humans. Causes blindness and lymphatic infections in adults. Dangerous to pregnant women, causes severe neurological defects in unborn children. Cats are part of life cycle, oocysts excreted in feces. Contact with infected feces or meat are means of transmission. u Cryptosporidium: Causes respiratory and gallbladder infections in immunosuppressed individuals. Found in intestines of mammals and water. Major cause of death in AIDS patients. u Cyclospora cayetensis: New parasite (1996) caused diarrhea associated with raspberries.
u Medically Important Protozoa (Continued) u 3. Ciliates (Phylum Ciliophora) u Move and obtain food using cilia. u Only known human pathogen is Balantidium coli, which causes a severe intestinal infection in pigs and humans. u 4. Microsporans (Phylum Mycrospora) u Obligate intracellular parasites, lack mitochondria and microtubules. u Discovered in 1984 to cause chronic diarrhea and conjunctivitis, mainly in AIDS patients.
Paramecium caudatum is a Ciliated Protozoan Conjugation Between Opposite Mating Strains
u VI. HELMINTHS (WORMS) u Characteristics u Eukaryotic, multicellular animals that usually have digestive, circulatory, nervous, excretory, and reproductive systems. u Worms with bilateral symmetry, head and tail, and tissue differentiation (endoderm, mesoderm, and ectoderm). u Parasitic helminths spend most or all of their lives in host and usually have the following specializations: u May lack a digestive system. Absorb nutrients from host’s food, body fluids, or tissues. u Have a reduced nervous system. u Means of locomotion is reduced or absent. u Complex reproductive system. Individuals produce many eggs that can infect another host.
u VI. u u u u HELMINTHS (Continued) Two main groups (phyla) Platyhelminths (Flatworms) Nematoda (Roundworms) Life Cycle Extremely complex Intermediate hosts harbor larval (developmental) stage. Definitive host harbors adult stage. Sexual reproduction strategies: u Dioecious: Male and female reproductive organs are found in separate individuals. u Monoecious (Hermaphroditic): One animal has both male and female sex organs. Most hermaphrodites copulate with other animals, a few copulate with themselves.
u VI. u u u u HELMINTHS (Continued) I. Platyhelminths (Flatworms) Flattened from front to back. Include: 1. Trematodes or Flukes Leaf shaped bodies Ventral and oral suckers for attachment and sucking fluids from host. Some can absorb nutrients through their cuticle. Named for host tissues in which adult lives. u Blood Fluke (Schistosoma spp. ): Cause schistosomiasis which affects over 400, 000 immigrants in U. S. and 200 million people worldwide. Cause damage to blood vessels, liver, and many other organs. Live in waters contaminated with feces, burrow through skin of human and enter the circulatory system, particularly abdominal and pelvic veins.
Free-Living Flatworm Planaria Life Cycle of Blood Fluke (Schistosoma)
VI. HELMINTHS (Continued) I. Platyhelminths (Flatworms) 1. Trematodes or Flukes u Asian Liver Fluke (Clonorchis sinensis): Infests gallbladder, bile ducts, pancreatic ducts, causes biliary cirrhosis and jaundice. Cannot be transmitted in U. S. because intermediate hosts are not available. u Lung Fluke (Paragonius westermani): Lives in bronchioles of humans and other animals. 12 mm long. Infection from eating undercooked crayfish.
u VI. u u u II. Nematodes (Roundworms) Cylindrical body tapered at each end. Have a complete digestive system: mouth, intestine, and anus. Body is covered by tough cuticle that resists drying and crushing. Most species are dioecious: separate males and females. u u HELMINTHS (Continued) Males are smaller than females and have one or two spicules on posterior end. Over 90, 000 known species. Most are free-living. Only about 50 are human parasites. Life cycle of parasitic nematodes is simpler than that of flatworms. Infections can be caused by eggs or larvae.
Comparison of Body Organization of Flatworms, Roundworms, and Earthworms Flatworm Roundworm Earthworm
u u II. Nematodes (Roundworms) Continued Infectious eggs u u u Pinworm (Enterobius vermicularis): Spends entire life in human host. Adults live in large intestine. Female lays eggs in perianal region which causes itching. Up to 90% of children are infected through contaminated clothes or bedding. Infection usually disappears after a few years. Ascaris (Ascaris lumbricoides): Large nematode, up to 30 cm. Dioecious with sexual dimorphism. Live in small intestines of humans, horses, and pigs. Eggs can survive in soil for long time. Infectious larvae u u u Adult Hookworm (Necator americanus): Live in small intestine of humans, eggs are excreted in feces. Enter host by penetrating skin. Enters bloodstream, travels to lungs, swallowed in sputum. Avoided by wearing shoes. Trichinosis (Trichinella spiralis): Reproduce sexually in small intestine of humans. Obtained from eating undercooked pork. Larvae enter blood vessels and form cysts throughout body. Anisakines (Wriggly worms): Infected fish and squid. Killed by freezing and cooking.
Pinworm (Enterobius vermicularis) Source: http: //www. biosci. ohio-state. edu/~parasite/a-h. html
Pinworm Eggs (Enterobius vermicularis) Source: http: //www. biosci. ohio-state. edu/~parasite/a-h. html
Ascaris (Ascaris lumbricoides) Source: http: //www. biosci. ohio-state. edu/~parasite/a-h. html
Head of Ascaris (Ascaris lumbricoides) Notice three lips characteristic of Ascaris Source: www. soton. ac. uk/~djab/ascaris. html
u VII. Arthropods as Vectors u Segmented bodies, hard exoskeleton (chitin), and jointed legs. u Largest phylum in animal kingdom, over 1 million species. u Several classes of arthropods: u u u Arachnida (8 legs): Spiders, mites, and ticks. u Crustacea (4 antennae): Crabs, crayfish. Most are aquatic. u Insecta (6 legs): Largest group of living organisms on earth. Include bees, flies, lice, cockroaches, mosquitoes, and fleas. Arthropods that transmit microbial diseases are called vectors. How do arthropod vectors transport microbes? u u Mechanically: Houseflies and cockroaches. Hosts: Tick vectors of Lyme disease. Mosquito vectors of malaria and encephalitis.
Arachnids are Arthropods with Eight Legs Lyme Disease Vector Spotted Mountain Fever and Tularemia Vector Source: www. soton. ac. uk/~djab/ascaris. html
Insects are Arthropods with Six Legs Tse-tse Fly: Host Vector of African Sleeping Sickness Source: www. soton. ac. uk/~djab/ascaris. html
Crustaceans are Arthropods with Four Antennae
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