Microbio Exam II: chapter 5, eukaroytic diversity

Eukaryotic supergroups (6)

Exacavata, chromalveolata, rhizaris, archaeplastida, amoebozoa, opisthokonta

Fungi benefits

decompose dead plants, recycle vital elements, food and antibiotic production

mycology

the study of fungi

structures in fungi

thallus, hyphae, mycelium

thallus

body

hyphae

fungal filaments that grow by elongating at the tips

septate hyphae

contain cross-walls

coenocytic hyphae

not divided

vegetative hyphae

below the subsurface, obtains nutrients

aerial hyphae

reproduction

conidia

open spores

mycelium

mass of hyphae

Yeasts

nonfilamentous unicellular fungi

budding yeasts

divide unevenly, forms 24 daughter cells, ex: sacchromyces

fission yeasts

divide evenly, ex: schizosacchromyces

dimorphic fungi

Forms a yeast at 37C and a mold at 25C

Fungal reproduction

sexual and asexual

Types of asexual spores

conidiospore, arthroconidia, blastoconidia, chlamydoconidium, sporangiospore

conidiospoe

asexual spore not enclosed in a sac

arthroconidia

asexual spore formed from fragmentation of septate hyphae

blastoconidia

asexual spore formed from buds of the parent cell

chlamydoconidium

asexual spore within a hyphal segment

sporangiospore

asexual spore enclosed in a sac

sexual spores

fusion of nuclei from 2 opposite mating strains --> diploid zygote --> meiosis --> haploid nuclei

Environmental and nutritional needs of fungi

pH 5, molds are aerobic, yeasts are facultative anaerobes, resistant to osmotic pressure

Medically important fungi phyla

mucoromycota, microsporidia, ascomycota, basidiomycota

mucoromycota

conjugation fungi, coencytic hyphae, reproduce asexually (sporangiospore) and sexually (zygospore)

Mucoromycota example

Rhizopus stolonifer: black bread mold

Microsporidia

No sexual reproductive, no mitochondria, obligate intracellular parasites

What diseases are caused by microsporidia

chronic diarrhea, keratoconjunctivitis

ascomycota

sac fungi, septate hyphae, some are anamorphic (cant reproduce sexually)

Reproduction in ascomycota

1. asexually: conidiospore
2. sexually: nuclei fuse in ascus sac forming an ascospore

Ascomycota examples

saccharomyces, candida, aspergillus

Basidiomycota

club fungi, septate hyphae, mushroomssssss

Basidiomycota reproduction

1. Asexual: conidiospores
2. basidiospores are formed externally on the base (basidium)

Basidiomycota key genera

agaricus, amanita (highly poisonous), cryptococcus

mycosis

fungal infection

five different types of mycoses

systemic, subcutaneous, superficial, opportunistic, cutaneous

systemic mycoses

deep within the body, impact tissues and organs

subcutaneous mycoses

penetrate the stratum corneum (top skin layer), ex: sporotrichosis

sporotrichosis

caused by sporothrix schenkii which enters a wound and causes a small ulcer, common in gardeners

superficial mycoses

localized, ex: hair shafts

opportunistic mycoses

fungi harmless in normal habitat are pathogenic in a compromised host

cutaneous mycoses

affect hair skin and nails, also known as dermatomycoses

Dermatomycoses genera

trichophyton, microsporum, epidermophyton

trichophyton

infect hair skin or nails

microsporum

involves only hair or skin

epidermophyton

affects only skin and nails

histoplasmosis

caused by histoplasma capsulatum, acquired from conidia in bird or bat droppings, geographically isolated to the mississippi and ohio rivers. forms lung lesions

histoplasma capsulatum

dimorphic fungus, yeast form grows in macrophages, resembles tuberculosis

coccidioidomycosis

also known as valley fever or san joaquin fever, caused by coccidioides immitis, American SW

coccidioides immitis cycle

tubular hyphae segment into arthroconidia and become airborne, they are inhaled and form a spherule where endospore develop and are released

Blastomycosis

caused by blastomyces dermatitidis, symptoms similar to bacterial pneumonia, located in the mississippi area

blastomyces dermatiditis

dimorphic fungus, grows in soil, causes blastomycosis

Pneumocytis pneumonia (PCP)

caused by pneumocystis jirovecii, causes pneumonia in immunocompromised patients, primary indicator of AIDS, found in alveoli, fatal

PCP reservoir

neonates

PCP cycle

Trophozoites develop into cysts

candidiasis

overgrowth of candidia albicans which forms pseudohyphae that allow it to avoid phagocytosis and invade deeper tissues

Thrush

overgrowth of candida albicans in the oral cavity

What makes you at higher risk for candidiasis

oral contraceptives, pregnancy, diabetes, obesity

Cryptococcosis

caused by cryptococcus neoformans, transmitted by respiratory route, spreads to CNS to cause meningitis

cryptococcus neoformans

soil fungus from pigeon and chicken droppings, has a heavy capsule to resist phagocytosis

asperigillus fumigatus

causes aspergillosis, compost piles

rhizopus and mucor

bread mold spores

mycotoxins

toxins produce by fungi that can cause blood disease, nervous system disorders, kidney and liver damage, cancer

ergot poisoning

mycotoxins produced by claviceps purpurea, grains like rye, gangrene and hallucinations

aflatoxin poisoning

mycotoxins produced by aspergillus flavus, peanuts, causes liver cirrhosis and cancer

asperigillus niger

production of citric acid

asperigillus terreus

produces statins that help treat high cholesterol

saccharomyces cerevisiae

bread, wine, hep B vaccine

trichoderma

produces cellulase for cotton softening and clear fruit juice

taxomyces

makes taxol (anti cancer drug)

tolypocladium inflatum

cyclosporine

coniothyrium minitans

biological pesticide

paecilomyces

kills termites

lichens

mutualistic combination of green algae and fungus

three morphological categories of lichens

cructose (flush), foliose (leaflike), fruticose (fingerlike)

Body (thallus) of lichens are made of

1. medulla: hyphae growing around algal cells
2. rhizines: hyphae projections below the body
3. cortex: protective coating over algal layer

How are lichens environmental indicators

they are first colonizers on rock and soil, they disappear when air is polluted with sulfur dioxide

How do lichens represent a mutualistic relationship

algae produces carbs for the fungus and the fungus protects the algae

Economic importance of lichens

litmus dye, antimicrobial, Usnea

Algae

unicellular, filamentous photoautotrophs, require water for nutrients and reproduction

Location of algae depends on

nutrient availability, wavelengths of light, surfaces to attach to

pneumocyst

floating gass bubble in algae that provides buoyancy

oomycotes

fungus like (chemoheterotrophic) algae, plant parasites for potatoes and soybeans

Types of algae

brown kelp, red, green, diatoms, dinoflagellates

Brown algae

cellulose and alginic acid cell walls, produce algin (food thickener)

red algae

grow deep at blue wavelengths, branched thalli, produce agar, carrageenan, and lethal toxins

green algae

cellulose cell walls, chlorophyll a and b, store starch, gave rise to terrestrial plants

diatoms

pectin or silica cell walls, store oil for energy, produce domoic acid

How do diatoms impact human health

consumption of mussels that have eaten diatoms causes neurological disease from domoic acid

how do diatoms impact industry

carbon in the form of oil gets trapped in sediments which causes petroleum formation

dinoflagellates

cellulose in plasma membrane, component of plankton, unicellular

paralytic shellfish poisoning

caused by saxitoxins produced by dinoflagellates

pfiesteria piscicida

genus of toxic dinoflagellate that causes massive fish kills

Role of algae in nature

fix CO2, produce 80% of earths oxygen, algal blooms

protozoa

unicellular eukaryotes, complex lifecycles

Life cycle of protozoa

1. vegetative state: trophozoite
2. asexual reproduction: fission, budding, schizogony
3. sexual reproduction conjugation

Protozoa and cysts

some form cysts to help them survive outside the host environment, similar to an endospore but has reproductive function

Characteristics of protozoa

require a large supply of water, outer protective pellicle, specialized food structures