Transcript Lab #4
Lab #4 Fungi The Kingdom Fungi • unicellular (yeasts) to multicellular, heterotrophic organisms – absorption of nutrients obtained by digesting organic matter outside the fungal body – essential role (with bacteria) in decomposition – return nutrients to the environment through this digestion • mutualistic association of some fungi with algae – known as mycorrhizal fungi – the association is called a mycorrhiza (mycorrhizae = plural) • others are parasitic – Athlete’s foot, ringworm, potato blight, wheat rust Fungal Diversity • • • • • Chytrids: the chytrids Zygomycetes: molds Glomeromycetes: mycorrhizal fungi Ascomycetes: sac fungus Basidiomycetes: club fungus Zygomycota • includes Rhizopus stolonifer – common bread mold • like all multicellular fungi – made up of threadlike filaments called hyphae – fuzzy appearance on the bread • within the bread is the majority of the fungus – mat-like organization called a mycelium Zygomycota • sexual reproduction – when two mycelia of opposite mating types (+ and -) grow next to each other – extend toward each other and form 2 gametangia in between each other – 2 gametangia fuse to produce a zygosporangium – zygosporangia is the site of karyogamy – fusion of haploid nuclei to produce diploid nuclei – meiosis results in the production of haploid spores – so sexual reproduction results in the production of haploid spores that develop into new mycelia Zygomycota • progression of zygomycota gametangia into zygosporangium (with zygospores) • Zygomycota asexual reproduction – some hypha stand upright and develop sporangia at their tips (haploid) – structures that contain haploid spores that multiply via mitosis and develop into many more haploid spores – so asexual reproduction results in the production of haploid spores that develop into new mycelia • • • spores are dispersed by air currents each fungal spore develops into a mycelium these new mycelium can either undergo a new round of sexual reproduction or can undergo asexual reproduction • main cue is the environment • favorable environment = asexual reproduction • hostile environment = sexual reproduction Phylum Zygomycota Zygosporangia Phylum Zygomycota Sporangium Sporangium & zygosporangium Rhizopus gametangia Sporangium Aspergillus sporangium sporangium Ascomycota • • • • • the sac fungi ascospore-producing fungi edible fungi, morels and truffles single celled ascomycotes include a wide group of species called yeasts also includes several deadly plant and animal diseases – ergotism Ascomycota • sexual reproduction results in the development of an ascus – in which are the meiotic development of ascospores – multiple asci develop within a structure called an ascocarp – edible portion of the fungus – this ascocarp can be a closed spherical structure (perithecium) with a pore at the top for ascospore release – or an open cup-like structure (apothecium) apothecium Ascomycota • asexual reproduction – spores produced at the tips of reproductive hyphae (conidiphores) – these spores are known as conidia – given these fungi a powdery appearance Phylum Ascomycota: the ascocarp Phylum Ascomycota Phylum Ascomycota hyphae bearing asci with 8 ascospores 8 ascospores Phylum Ascomycota: the yeasts Saccharomyces cerevisiae Candida albicans Candida infection of the throat • MORELS: VERY EXPENSIVE!!! – Sponge, pinecone and honeycomb appearances surface of a morel is covered with definite pits and ridges – Size: 2" to 12" tall. • The common morel (Morchella esculenta): as it ages, both the white ridges and dark brown pits turn yellowish brown, and it becomes a "yellow morel." – If conditions are right the "yellow morel" can grow into a "giant morel," which may be up to a foot tall. • The black morel or smoky morel (Morchella elata): The ridges are gray or tan when young, but darken with age until nearly black. The pits are brown and elongated. • When and Where: From spring to early summer. Morels are found on the ground in a variety of habitats, including moist woodlands and in river bottoms. • Cautions: there are false morels which are poisonous Basidiomycota • • • • club fungi basidiospore-producing fungi includes the rusts and smuts also the more familiar puffballs and mushrooms (edible) • plus the non-edible & poisonoustoadstools • most species undergo only sexual reproduction – those undergoing asexual reproduction form conidia via mitosis Basidiomycota • mushroom is a reproductive structure called a basidiocarp • on the underside of the pileus (cap) are gills bearing dikaryotic basidia (nuclei have NOT fused) – basidium = singular • fusion (karyogamy) results in the basidium and meiosis then produces 4 haploid nuclei per individual basidium • each nuclei develops into a basidiospore – located at the tip of the basidium • basidiospores are then released and carried by air current • spore germination results in the production of a new mycelium • mushrooms can grow within hours in a moist environment Mushrooms • • • • • fruiting body of a club fungus purpose is to disperse spores provide the best non-animal source of vitamin D some also provide many antioxidants along with vitamins B and C contain chitin - non-soluble protein – chitin can result in the elimination of bile from the human intestinal tract – new bile is formed from the breakdown of cholesterol - therefore it improves cardiac health • rich in beta-glutan – heart healthy carbohydrate that is also found in oats • poisoning can occur – some people are more susceptible to the toxins within mushrooms – can cause varying degrees of GI distress – symptoms usually appear within 2 to 3 hours and the victim recovers over time Mushrooms • classic mushrooms are referred to as the gill fungi – gills under the cap – some of the best edible mushrooms – numerous species gill fungus = Shitake Phylum Basidiomycota Phylum Basidiomycota: the basidiocarp Amanita Cogumelo Shelf fungus Puffball Phylum Basidiomycota gill with basidium and basidiospores gill with basidium and basidiospores Mushrooms • also have coral fungi, pore fungi, tooth fungi and the stinkhorns – pore fungus (shelf fungus) – no gills under the cap • edible species - known as the bolets • some can grow very large on trees – Polyphorus squamosus – 12 inches across – tooth fungus – Pompom or Lion’s mane • “teeth” bear basidia with spores = hymenophores • many are delicacies – stinkhorns – inside is almost empty • covered with a dark goo that stinks – attracts insects • the goo contains the basidia and basidiospores and stick to the insects legs • not posionous but not edible either pore fungus tooth fungus stinkhorn Edible mushrooms • • • PUFFBALLS: Depending on their size, puffballs have been mistaken at a distance for everything from golf balls to sheep. – round or pear-shaped mushrooms are almost always whitish, tan or gray – interior of a puffball is solid white at first, gradually turning yellow, then brown, then black spores) as the mushroom ages – should have no sign of gills, stalk or pileus When and Where: Late summer and fall; in lawns, open woods, pastures, barren areas. On soil or decaying wood. CAUTION: Amanitas, when young, can resemble small puffballs Edible mushrooms • SHAGGY MANE (Coprinus comatus): The shaggy mane or lawyer's wig is so large and distinctive that with a little practice you can identify it from a moving car. – The cap of a fresh specimen is a long, white cylinder with shaggy, upturned, brownish scales. The gills are whitish, and the entire mushroom is fragile and crumbles easily. Most important, as the shaggy mane matures, the cap and gills gradually dissolve into a black, inky fluid, leaving only the standing stalk. • When and Where: Spring, summer and fall, growing in grass, soil or wood chips. Often seen scattered in lawns and pastures. • OYSTER MUSHROOMS (Pleurotus ostreatus) • large white, tan or ivory-colored mushroom is named for its oyster shell-like shape. • white gills running down a very short, off-center stem. Spores are white to lilac, and the flesh is very soft. • When and Where: Spring, summer, fall and during warm spells in winter. On trees and fallen logs. • Cautions: This mushroom has a number of look-alikes, (including Crepidotus and Lentinus spp.), but none are dangerous. they may, however, be woody or unpleasant-tasting. • CHANTERELLES (Cantharellaceae) • a great favorite of European mushroom hunters and are becoming more popular in the United States. • funnel-or trumpet-shaped and have wavy cap edges. • most are bright orange or yellow • to make sure you have a chanterelle, check the underside of the cap – some chanterelles are nearly smooth underneath, while others have a network of wrinkles or gill-like ridges running down the stem. • When and Where: Summer and fall; on the ground in hardwood forests. Usually found in scattered groups. • Cautions: take extra care at first that you do not have the poisonous jack-o-'lantern these have knifelike gills and grow in the tight clusters on wood or buried wood, rather than on the ground. Poisonous mushrooms • Amantia verna – Destroying Angel – mushrooms of the Amantia variety produce amantin – one cap can kill a grown man – starts its growth looking like a small puffball which breaks open as it grows – adults have parasol shaped caps – white, yellow, red or brown – stem has a saclike cup at the base of the stem & a ring on the stem – white gills & white spores – amantin – destroys liver and kidney cells • False morels – can be toxic to some people, edible to others – toxic chemical – monomethylhydrazine – amounts can vary from mushroom to mushroom – MMH causes severe intestinal distress, severe headaches and can be fatal – toxicity can be decreased with certain cooking techniques Poisonous mushrooms • Little brown mushrooms – some are toxic, some are hallucinogenic, few are deadly – catchall category of mushrooms varying from small to medium-sized shrooms – hard to identify – some contain the amantin toxin • Jack O-Lanterns: bright orange – glows in the dark – greenish glow – look, smell and taste very good – fruity flavor – can cause GI distress but are not life threatening Hallucinogenic ‘Shrooms • Aztecs used the term “teonanacatl” to mean flesh of the gods • 1. Psilocybin – contains the hallucinogenic compounds psilocybin and psilocin – – – – – serotonin agonist restlessness, increased heart-rate and visual and auditory hallucinations increased body temp - should NOT be treated with aspirin or other salicylates 30 to 60 minutes within ingesting - lasts about 4 hours excreted in the urine – UNALTERED by human physiology!!! Hallucinogenic ‘Shrooms • 2. Amanita muscaria – – – – – also known as fly agaric – ability to attract and kill flies contains the hallucinogens muscimol and ibotenic acid acts by mimicking the neurotransmitter GABA – GABA agonist binds GABA receptors on neurons – activates these neurons feelings of euphoria, hallucinations, muscle jerks, drowsiness, sweating, pupil dilation and increased body temperature – 30 to 90 minutes within ingestion – most intense after 2 to 3 hours – usually results in a deep sleep Lichens • symbiotic associations between fungi and algae or another photosynthetic bacteria • fungal component is usually an ascomycote or a basidiomycote • the lichen body is called a thallus – variety of shapes and forms and colors • lichen body forms – 1. foliose or leafy thallus – 2. crustose or crustlike thallus – 3. fructicose or branching thallus Lichens fructicose lichens foliose lichens crustose lichens