Lab 7 - Kingdom Fungi
Introduction to Fungi
Our laboratory today concentrates on two very unusual groups of organisms, thefungiand the slime molds. Fungi were initially grouped along with algae(as "thallophytes"), partly due to the fact that most fungi room composed the longslenderthreads the superficially resemble certain species of algae. Numerous mycologiststhought that fungi to be descended from birds or primitive tree thathadlost their ability to photosynthesize. The most recent molecularstudies,however, expose that fungi room actually more closely regarded animalsthan to plants.
You are watching: The body of most fungi consists of threadlike
By currently it need to be coming obvious that our category oforganismsis often tentative and arbitrary, a finest guess based on currentinformation.As a taxonomic souvenir that our earlier hypothesis, fungi are groupedintodivisions, a taxonomic term used for tree (the indistinguishable term foranimalsis phylum). Plenty of other usual botanical state are provided to describeanalogousstructures in fungi. This superficial similarities may be the resultofconvergent evolution between fungi and also algae.
There room over 100,000 known varieties of fungi, however the differencesbetweenspecies space not always readily apparent. Subtle differences inbiochemistryset countless fungal types apart. Fungi space heterotrophic, andmanyfungi space parasitic. Fungi and other organisms that feed ondeador decaying issue are referred to as detritivores. Many varieties offungiare predators, capturing their prey v tiny lassos orminiaturemissiles or toxic chemicals.Fungi and bacteria are an important to the extension oflifeon Earth. They are the planetary decomposers, breaking under organicmatterinto a form usable by other organisms. Just fungi are capable ofbreakingdown lignin, the compound that adds stiffness come the cell wallsof plants.
Fungi also participate in two essential symbioticrelationships.Fungi can type lichens, an combination of a fungus v a greenalgae or a cyanobacteria. Lichens room usually presented as a classicexampleof mutualism, where each partner benefits native therelationship,but some authorities believe that this relationship could be a kind ofcontrolled parasitism. Particular fungi are also symbiotic with the rootsor gametophyte step of many varieties of plants. These mycorrhizaecan flourish inside root (endomycorrhizae), or on the outside ofroots(ectomycorrhizae).The human body of a fungi consists of many little threadscalledhyphae,which intertwine to kind a larger body referred to as a mycelium. Thecellwalls of fungal hyphae room made that polysaccharides, favor those ofplantsor bacteria, but they likewise contain chitin. Chitin, composed ofcellulosewith nitrogenous groups attached, is uncovered in many types of animaltissues(like the exoskeletons that insects, or the rasping tongue that the snail).Unlike strands of algae, the cross walls or septae in between thecellsin fungal hyphae are regularly incomplete, or doing not have altogether. Fungalstrandsare therefore often multinucleate.
Fungal hyphae only type a complete cross wall at the really tip that ahyphaeundergoing sex-related reproduction. This lack of overcome walls might be thesecretbehind the evolutionary success that this widespread team of organisms.Fungi have the right to move products like nutrients and proteins ago and forthveryquickly through cytoplasmic streaming. Fungal cradle isextracellular,with the hyphae secreting powerful enzymes to digest the host tissue,thenabsorbing the failure products with their cabinet walls. Organismsthatfeed in together a fashion are called saprobes.We use plenty of of the same terms because that fungal reproductionthat we usage to define analogous frameworks in plants. Spores developin a sporangium. A hyphal tips that construct into a sexualreproductivestructure is dubbed agametangium. The nuclei inside the fungalhyphae are haploid, unequal the diploid cell of many plants andanimals.Therefore, fungi don"t have to undergo meiosis before fertilization.
Fungi reproduce through conjugation, a blend of nuclei analogousto conjugation in bacteria and certain species of algae. The hyphae oftwomatingstrains of fungi (usually described as+ or -) lieside by side, and also each grows a forecast toward the other. Theseprojections,called gametangia, meet and fuse together. The intervening cellwalls rest down, so that nuclei from every strand deserve to then fusedirectlyinto a diploid zygote. This zygote, the just diploid phase in the lifecycle the fungi, experience meiosis to type four haploid spores,containedin a little sporangia. A spore is a cell the candevelopdirectly right into a finish adult haploid organism. Like most spores,fungalspores are enclosed a one-of-a-kind protective wrapper the guards againstmechanicalor chemistry damage.
The blend of nuclei in link is delayed in both ascomycetesandbasidiomycetes. The two nuclei continue to lie side by side,reproducingseparately by mitosis, until each to move compartment in the hyphalstrandmay contain 2 nuclei. The hyphae of this fungi are dubbed dikaryotic,to differentiate them native monokaryotic hyphae. Fungi have the right to alsoreproduceasexually, generally by creating groups of lengthy hyphae called conidiophores,which resemble a tiny brush. The tips of these conidiophores fragmentintohundreds of small haploid spores called conidia.Each department of fungi is identified by specialsexualstructures distinctive to the division. Sexual reproduction in zygomycetesresults in the formation of zygospores, structures whichundergomeiosis and germinate directly into brand-new hyphae.
Ascomycetes give birth by developing a mushroom-like fruiting bodycalledan ascocarp. Conjugation, with delayed fusion of nuclei,producesdikaryotic hyphal strands. The advice of this strands type cross wallstoisolate a tiny sac or ascus. Ascomycetes room oftenreferredto assac fungi. The two nuclei in the ascus fuse with each other intoa diploid nucleus, which climate undergo meiosis to form four haploid ascospores,which then division again through mitosis to kind eight haploid ascospores.Asexual reproduction is completed by conidia bearing conidiospores.
Basidiomycetes create fruiting bodies called basidiocarps.Club-shapedstructures dubbed basidia cave from the underside of themushroom,lining slim flaps of tissue called gills. Within this basidia,nuclear fusion occurs, adhered to by meiosis to produce four basidiospores.Because of the shape of the basidium, basidiomycetes space sometimescalledclubfungi.
By concentrating on sex-related reproduction in classifying fungi, us fellintoa taxonomic trap. Many species of fungi have actually never to be observed toundergosexual reproduction. Us lump these species together in the artificialtaxonDeuteromycota, the imperfect fungi orfungi imperfecti. Most ofthese fungi imperfecti are more than likely ascomycetes.Taxonomy
Division Zygomycota - molds, Rhizopus (bread mold)
Division Ascomycota - sac fungi (yeasts, morels, truffles)
Division Basidiomycota - club fungi (mushrooms, puffballs,shelffungi, rusts, smuts)
Division Deuteromycota - mushroom imperfecti - Penicillium,Aspergillus
Division Myxomycota - plasmodial slime molds, Physarum
Division Acrasiomycota - moving slime molds, DictyosteliumTerms mycology heterotrophs helminth predators saprobes detritivores hyphae mycelium (-ia) septae chitin lignin synergy mutualism lichens crustose foliose fruticose mycorrhizae endomycorrhizae ectomycorrhizae multinucleate cytoplasmic streaming spore sporangium (-ia) gametangium (-ia) conjugation mating strain monokaryotic dikaryotic conidia conidiophore zygospores stolon rhizoid sporangiophore sac mushroom ascus ascocarp mushroom ascospores budding club fungi basidium (-ia) basidiocarp basidiospores mushroom cap mushroom gills fairy ringCharacteristics of Divisions
Division Zygomycota - molds, Rhizopus (bread mold)
All members of this group kind characteristic sex-related structurescalledzygospores.When the mold reproduces sexually, its’ gametangium looks choose twolittleice cream cones smashed together. The zygote divides through meiosis come formhaploid spores.
Asexual reproduction in zygomycetes, likeRhizopus, producesa growth pattern resembling the of the strawberry. Long hyphae calledstolonsrun along the surface ar of your food, regularly sinking downroot-likeprojections dubbed rhizoids. Long stalks calledsporangiophoresarise from the stolons, bearing small roundsporangia, i beg your pardon breakopen to relax spores.
Division Ascomycota - sac fungi (yeasts, morels, truffles,Dutchelm disease, chestnut blight, ergot)
Ascomycetes, often referred to as sac fungi, have a wide variety of bodyforms,from the single-celled yeasts to mushroom-like morels. Themushroom-likefruiting body is referred to as an ascocarp. They reproduce asexually through meansof unique hyphae referred to as conidiophores, i m sorry fragment come producethousandsof tiny spores referred to as conidia. Yeasts type tiny buds that break turn off andgrow right into larger cells. Sex-related reproduction in this department involvesconjugation,with the 2 nuclei fusing with each other at the guideline of a hypha to kind anucleatedsac called an ascus. Meiosis creates 4 haploid nuclei, i beg your pardon divideagainby mitosis to form the characteristic 8 ascospores.
Ergot fungi of the genus Claviceps infests rye bread andothergrains. All by itself, this small fungus has altered the food ofhumanhistory in locations like Russia wherein it is widespread. Civilization eatinginfectedrye bread were believed to have been possessed by the devil, since oftheir wild dancing and uncontrolled behavior. We recognize now the thechemicalcausing this actions is none other than LSD. Mar Matossian composed awonderfulbook about the effects of ergot and also other fungi on person affairs,calledPoisons of the Past: Molds, Epidemics and also History, (Yale UP, 1989). Shealso suggests that ergot poisoning may have been behind the Salem witchtrials!
Division Basidiomycota - club fungi (mushrooms, puffballs,shelffungi, rusts, smuts)
Basidiomycetes, often called club fungi, kind a basidiocarp, thefruitingbody frequently called a mushroom. The underside that the mushroom lid isfilledwith thin plates referred to as gills, which lock superficially resemble. Thesegills organize club-shaped sexual reproductive structure dubbed basidia(-ium).The nuclei inside the basidia fuse to kind a 2N zygote, which undergoesmeiosis to type 4 haploid basidiospores, which appear at the advice ofthebasidia. Asexual reproduction is an extremely rare in this group.
Most the the body of a basidiomycete is actually growing under theground.Because the hyphae of basidiomycetes flourish at approximately equal rates fromthecenter the growth, as soon as the hyphae emerge from the ground as thefruitingbodies we call mushrooms, the mushrooms often appear in a largecircularring. These rings of mushrooms are dubbed fairy rings, and also insimplertimes lock were thought to it is in magical places, whereby the fairies come todance at night. ~ a hefty rain, you can see this fairy ring inyardsand parks almost everywhere the city.
Division Deuteromycota - fungi imperfecti - Penicillium,Aspergillus
This “catch-all category” has many varieties of mushroom which havenever been observed come reproduce sexually, and also cannot, therefore, beclassedin the various other three Divisions, although many of these room probablydifferentspecies that ascomycetes. Lock reproduce asexually in a manner comparable toascomycetes, with hyphae called conidiophores fragmenting right into numerousconidiospores. Penicillin and also Aspergillus are common fungi imperfecti.To Do and also View
Examine the zygomycete Rhizopus top top display. There space twoRhizopusplates come examine. The an initial shows a normal society of Rhizopus,such together you might find lurking ~ above a part of bread or various other food in theback that the fridge. Find and identify the stolons, rhizoids,sporangiophoreandsporangia. The second plate shows two mating strains ofRhizopusthathave developed several zygospores.
Examine slides that Rhizopus to obtain a closer look atthesereproductive structures.
Examine the ascomycetes top top display. Note the warty appearanceof the ascocarp the the morel, a usual edible ascomycete.
Examine ls slides that the ascomycete Peziza, dubbed cup fungi.Look for the ascus and ascospores at the top of thecup.
Examine slides of the yeast Saccharomyces. Yeast is aunicellular fungi, a curious ascomycete that commonly reproducesasexuallyby budding, creating a brand-new cell that establishes as a smaller budattachedto the parent cell.
Examine the basidiomycetes ~ above display. Shelf fungi are oftenfound top top dead and decaying trees.
Observe the sliced edible mushrooms. Notice the method the gillshang down listed below the cap.
Examine cs slides that Coprinus, a usual basidiomycete.Observethe basidia and basidiospores located on the political parties ofthegills.
Examine the deuteromycete Arthrobotrys. This curious funguscatcheslive nematodes (little worms), by constricting little loops developed bythehyphae, much like cowboys use a lasso come rope an errant steer.
Examine the deuteromycete Penicillium. You often see thisfungusgrowing ~ above stale bread and also cheese. It is the source of the antibioticpenicillin.
Examine the deuteromycete Aspergillus. Some varieties of thisdeuteromyceteare offered in the manufacture of soy sauce. This organism typifies theconfusionthat have the right to arise in fungal taxonomy. Numerous mycologists divide Aspergillusas one ascomycete.
Examine slides the Penicillium. Note the conidiophoresand conidia.
Examine slides ofmycorrhizae. Why is this symbiotic relationship so important?Fungal Symbiosis
Examine the lichens top top display. Notice that lichens come inthreebasic forms: crustose (flat crust, frequently seen top top rocks), foliose(leaf like), and fruticose (highly branched).
Examine slides of the lichen thallus (body). An alert the algalcells towards the top, and the tangle that fungal hyphae below.
Examine slides the mycorrhizae. Watch the fungal hyphaewindingthrough the source tissues. The fungus can grow much much faster than therootsof the plants it interacts with, and also can attain nutrients from a largearea of soil. The funnels this nutrients ago to the plant, in exchangefor several of the save food in the root.Things come Remember
Know the basic life bicycle of fungi. The life cycleofRhizopus,will offer as usual fungal life cycle. Compare and contrast thespecialstructures distinct to sexual reproduction in each department of fungi.Ecological, Evolutionary, and also Economic Importance
Many fungi room edible, including gourmet fungi choose morels andtruffles.
Without fungi we would certainly have nosoysauce, no fermented tofu (big deal!), no saki, no soybean beans sauce, no beer,no wine,no bread, no cheese, and therefore (gasp) no pizza!!
Fungi reason many diseases, such together athlete"s foot, yeast infections,ring worm, and also histoplasmosis (lung disease). Mushroom are likewise the sourceof plenty of antibiotics, consisting of penicillin.
Fungal rusts and also smuts are significant agricultural pests.
Many plants rely on symbiotic root fungi (mycorrhizae) forhealthygrowth.
Lichens are critical food for tundra pets like reindeer.
Ergot fungi space ascomycetes that develop LSD, a solid hallucinogen.This fungus, a form of ascomycete, readjusted the history of the Russianempire,and may have actually been the root reason of the Salem witch trials.Introduction to Slime Molds
Slime molds as sometimes referred to as "orphan phyla", sometimestreatedas a department of fungi, occasionally classified as a weird kind ofcolonialprotist. Provided the immense amount of material in the protist lab, we"veelected to examine them next to the mushroom which castle superficiallyresemble.Slime molds have the right to be one of two people plasmodial slime molds, choose Physarum,orcellular slime molds like Dictyostelium.
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The Acrasiomycota, or cellular slime molds, spend much oftheirlives as small creeping amoeboid cells, feeding on decayingvegetation.When the local food supply starts to run dry, a chemistry signal goesoutto reproduce, and also they swarm together, climb up end one one more toform a slug-like body. This fixed of cells even leaves a trace of slimebehind together it moves, prefer a genuine slug. It establishes a tiny stalk, with asporangium on top in i m sorry spores develop. Brand-new amoeba emerge from thedispersedspores.
The Myxomycota, or plasmodial slime molds, are basicallysimilarto the moving slime molds, but have a far more complex life cycle.Thefeeding stage, or plasmodium, has countless nuclei within a networkofcytoplasm. If girlfriend look closely you could see cytoplasmic streaming,the continuous back and also forth circulation of the slime mold"s cytoplasm, whichisthought come circulate oxygen and also food throughout the body. Slime moldsarea wonderful instance of what happens when you try to pen neat littlelabelslike plant, or animal, or mushroom on the tremendous diversity that livingthings!!Consider This
Mycorrhizal fungi were vital to the successful intrusion of the landsurface by primitive plants. Why? (Hint: What to be the surface ar of theland like prior to the an initial plants or animals?)
The biggest organisms on planet are not blue whales or dinosaurs, butbasidiomycetes. The existing record holder is a single basidiomycete,underlying37 acre of a Montana conifer forest. It is estimated to be 1,500 yearsold, and weighs about 10,000 kilograms (22,000 pounds!!). How do weknowthat every mushroom in the woods is a fruiting human body of the very same fungus?(Hint: what deserve to a study of genes tell us around these mushrooms?)Links come Explore
You"ll uncover a well-referenced guide to the latest discoveries aboutthese curious creatures in ~ the Tree the Life:http://phylogeny.arizona.edu/tree/eukaryotes/fungi/fungi.html Mycology in ~ LSU has actually a riches of links to the Kingdom Fungi: http://lsb380.plbio.lsu.edu/Home.html come eat or not to eat - sort out the edible mushroom from their toxicity kinat: http://www.conservation.state.mo.us/nathis/mushrooms/mushroom/index.htm check out the stunning fungal photography at prizes from the Kingdomof mushroom http://lsb380.plbio.lsu.edu/ima/index.html: Visionary mushroom - one "shroom" makes you larger, and also one "shroom"makesyou small... http://www.stainblue.com/
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