Fungi-The Rotten World About Us

Fungi-The Rotten World About Us

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What are the Fungi?

• Simple eukaryotic organisms with small genomes• Reproduce asexually and sexually by spores• Heterotrophs: similar to animals, many bacteria, they rely on

autotrophic organisms for fixed carbon and nitrogen• Filamentous growth (threadlike strands called hyphae), often

branching. Growth of hyphae is at tips. Exception: yeasts which are unicellular. Fungi don't have stems, leaves, roots nor a vascular system like plants.

• Easy to grow in the lab on defined media (like bacteria), make mutants and do genetic crosses

• Many species are well developed for molecular manipulations: Transformation, gene replacement, regulated gene expression

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Fungi in the News



Where do Fungi Fit in Classification Schemes?

Fungi are NOT Plants!!

Fungi are major players in Biotechnology

Many Spores are Produced



How Big are They?

What Are Fungi Doing?

• Decomposers– Saprobes are the primary agents for

biodegradation of plants and woody debris• ~85 billion tons of carbon as CO2 are returned to

the atmosphere annually

– Disease Agents: decay of living material • Plant pathogens destroy ~3 billion dollars of crops

annually in N. America

– Animal pathogens • in Arizona alone, the Valley Fever fungus is

responsible for $29 million in hospital costs annually

Fungi grow everywhere









But Fungi are not human



Chicago Worlds Fair - Human hair growing on Wood, Believe it Or Not

Fungi in History- First observation

• Rusts were observed by Romans on cereals– ~370 BC– they created a rust God,

Robigo to pray for deliverance from disease

More History-why the British drink tea instead of coffee

• Until 1870’s, Coffee was produced in Ceylon (Sri Lanka)

• Britian was full of Coffee houses• Coffee rust (Hemileia vastatrix) swept

through the coffee plantations between1869-1900

• Coffee growers switched to tea and rubber• Coffee production moved to Central and

South America

Fungi in History- the Irish move to America

• mid-1840’s Potato crops fail in Ireland• 2 million people died, 1 million emigrated to US• 1861 deBary shows this was due to a “fungus”, Phytophthora

infestans

• an emerging problem today due to a new strain




Fungi in History-Salem Witch Trials

• In 1692 several women in Salem, MA were accused of witchcraft and hung

• Evidence suggests their “strange behavior” may have been due to poisoning by the ergot fungus, Claviceps purpurea, a pathogen of rye

– This fungus produces toxins (alkaloids) that cause vasoconstriction.• It is the source of LSD• Can lead to cutting off of the blood supply and loss of limbs due to gangrene setting in• Some of its alkaloids are used for treatment of migranes, and induction of labor during

childbirth



Fungi- The New Asbestos?



New York TimesMagazine -

August 12, 2001

Stachybotrys chartarum

The sick building mold??????

Why are fungi important organisms for biotechnology?

• Produce 1o and 2o metabolites of industrial importance• 1o metabolites: end products of common metabolic pathways:

alcohol (ethanol), citric acid, itaconic acid• 2o metabolites: a diverse range of compounds that lack known

obvious functions in the growth and reproduction of the organism.

Production often occurs after growth has stopped, when nutrients are limited, but excess carbon is available.ex: Penicillin, cephalosporins, griseofulvin, cyclosporin, ergot alkaloids

• Well developed and understood secretory machinery allowing simple purification of products from culture medium.

• Relatively easily grown in mass culture and lots of practice (alcoholic beverage industry).

Manipulability of Fungi makes them attractive to industry

• Easy to grow, make mutants and do genetic crosses• Molecular biology is well developed: transformation, gene

replacement, regulated expression, total genome expression analysis, whole genome sequences are becoming available

• Saccharomyces cerevisiae was the first eukaryote to have its full genome sequenced (1996), Neurospora crassa (2001), several others in 2002


Saccharomyces cerevisiae: the brewers and bakers yeast

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A facultative anaerobe

Anaerobic respiration: produces alcoholC6H12O6 --------------> 2C2H5OH + 2CO2 + 2 ATP

Aerobic respiration: major product is CO2 C6H12O6 --------------> 6 CO2 + 6 H2 + 38 ATP

•One of the first organism’s exploited for biotechnology•Wheat production resulted in the settling of populations•Yeast was responsible for making bread rise

Fungi were the source of the first antibiotic



Penicillium notatum

The Penicillin Story

• Antibiotic production

– 1929: Discovered P. notatum as a contaminant on a bacterial plate by A. Fleming

– 1939: Chain and Florey first isolated drug to treat mice and a dying patient

– 1940’s: Florey and others worked on production for treatment of bacterial infections during WWII

– Production Improvements:• New species ID’ed: P. chrysogenum on a moldy cantelope in a Peoria, IL

market

• Culturing conditions: corn steeping liquor gave a 40X yield increase

• Mutagenesis and selection increased production from 80 mg/L to 7 g/L

• Synthetic modification of side chains produced more stable and effective drugs (ampicillin, carbenicillin)


Penicillin- the first antibiotic




Fleming’s 1929 plate

Quorn- eaten in the UK for 17 years, now available in the US

• Fusarium graminearum, isolated from a field in Marlow, Buckinghamshire

• Quorn is produced from mycelia grown in 155,000 litre airlift fermenters

• The filamentous nature of the biomass is responsible for the meat-like texture and appearance of the final product.

• Probably the most thoroughly tested food ever to appear on supermarket shelves, annual sales of Quorn are now in excess of £15 million in the UK.

“Quorn”-meat-free


www.quorn.com




Quorn products typically contain between 11 to 15 grams of protein per 100 grams, most of which comes from mycoprotein.

Citric acid isolated, from a fungus, is everywhere

• Citric acid production is from the fungus Aspergillus niger• Production is due to blockage of the TCA cycle by growing A.

niger under low pH conditions with enzyme inhibitors like Cu ions

• 1979, more than 100 million kilograms were produced in US and Europe

• Found as a flavoring (soft drinks, candies, desserts, jams jellies, wines, frozen fruits, also in gelatins

• citrates in blood transfusions act as anti-coagulants• Adjusts pH in hair rinses, hair dyes, used in creams and

ointments• Zinc citrate in toothpaste is a plaque inhibitor



Closer to Home- Valley Fever

Arthroconidia (transmission & scanning EM)

Infectious PhaseSpherules (Freeze-fracture EM)

What Is Valley Fever?

• Caused by a soil fungus Coccidioides immitis

(Coccidium-like not mild)

• Other names:– Coccidioidomycosis

(cocci)– Desert Rheumatism

• Infection results from inhaling arthroconidia

• Severity varies– Mild: 60%

– Moderate: 30%

– Complicated: 10%

• After infection, most persons develop life-long immunity

Coccidioides immitis

Valley Fever in the U.S.

50-70

30-50

10-30

5-10

<5

% Positive Skin Test

Coccidioidomycosis in Arizona (Reported)-a problem on the rise

0

600

1200

1800

2400

1990 1993 1995 1998 2001

High Profile Cases

Woods’ ills caused

by Valley Fever

By SUSAN CARROLL

Citizen Staff Writer__ ___________

Loren Wood’s lamented absence

from the NCAA Tournament, his two

back surgeries and upcoming months

of physical therapy are being blamed

on one culprit: valley fever.

TUCSON CITIZEN: May 5, 2000

Documents

Fungi-The Rotten World About Us