bis2c. biodiversity and the tree of life. 2014. l15. fungi

Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014

Lecture 15

!

Lecture 15 !

Fungi !!

BIS 002C Biodiversity & the Tree of Life

Spring 2014 !

Prof. Jonathan Eisen

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Where we are going and where we have been

• Previous Lecture: !14: Fungi and Symbioses

• Current Lecture: !15: Fungi and humans

• Next Lecture: !16: Plant Introduction

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Mean and Median Totals

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Whole Class Mean: 85.66 Median: 88 !Section A Mean: 85.94 Median: 88 !Section B Mean: 85.42 Median: 88


Distribution of Scores

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Question by Question Scores

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Can Mushrooms Save the Planet?

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Fungi

• Fungal mutualisms !Lichens !Mycorrhizae !Fungal farming by ants

• Fungi in the human microbiome

• Fungi and food

• Fungi and pharmaceuticals

• Fungi and industry

• Fungi and ecology7


Mutualisms

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Key Concepts: Mutualisms

• Mutualisms (symbioses where both partners benefit) are pervasive

• Determining what the partners provide for each other can reveal insights into ecosystems and each organism

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Figure 30.7 Lichen Body Forms

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Lichens

Lichens: fungus + photosynthetic microorganism

Together they can survive some of the harshest environments on Earth, such as Antarctica.

About 30,000 “species” are named for the fungal component.

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Figure 30.8 Lichen Anatomy

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Science Friday on Lichens

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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 14


Lichens for dyes

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Human uses of lichens: dyes


Mycorrhizae and Plant Mutualisms

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Mycorrhiza - a fungal root?

Plant

Fungus

In Greek, Myko = fungus Rhiz = root

Mycorrhizae


Ectomycorrhizae

Ectomycorrhizae—fungus wraps around the plant roots but does not penetrate cell walls. Web of hyphae penetrates soil around roots, increasing surface area for water and mineral absorption.

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Ectomycorrhizae – Ascomycota, Basidiomycota

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Ectomycorrhizae

20Eucalyptus

Betula

Pinus

Pseudotsuga

Quercus

• ~ 3-5 % of plants are ectomycorrhizal • Most are woody plants


Arbuscular mycorrhizae

Arbuscular mycorrhizae: hyphae enter root and penetrate cell walls but not the plasma membrane.

As in ectomycorrhizae, the fungus forms a vast web of hyphae in the surrounding soil and increases surface area for water and mineral uptake.

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Fungal farming by animals

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Fungi Gardening Ants are Monophyletic

25Schultz and Brady. 2008. PNAS 105: 5435.

Fungus gardening ants are a monophyletic group


Fungal farming by leaf cutter ants

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Fungal cultivation by animals Termites

Leaf cutter ants

Snails Ambrosia beetles


Fungi in the Human Microbiome

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Key Concepts: Ignored Fungi

• Fungi are much more prevalent and diverse than may be appreciated

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Great Plate Count Anomaly

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<<<<

Culturing Microscopy

CountCount

DNA

Censored

Censored

!30


Fungal Microbiome

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Cryptomycota

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Fungi in Our Homes

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Fungi and Food

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Penicillium

• Ascomycota.

• Ubiquitous in soil.

• Many different species with diverse functions.

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Photo 30.10 Penicillium digitatum growing on an orange.

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Penicillium camemberti

• Penicillium camemberti

• Used in production of Brie and Camembert cheeses

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Penicillium roqueforti

• Penicillium roqueforti

• Used in production of blue cheeses

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The brown mold Aspergillus:

• Aspergillus tamarii acts on soybeans to make soy sauce; A. oryzae is used to brew sake

• Other Aspergillus species grow on grains and nuts and produce extremely carcinogenic aflatoxins

• Aspergillus fumigatus was cause of the primary case in the steroid-injection outbreak

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Saccharomyces cerevisiae

• Ascomycota

• Grows naturally on many fruits (e.g., grapes)

• Also known as Brewer’s yeast and budding yeast

• Fermentation !Sugars ---> Acetaldehyde

+ CO2 --> Ethanol !Ethanol at high levels

kills inhibits the growth of the yeast

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Other fungi used in food/ food production?

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Figure 30.20 Some Lichens Are Edible

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Fungi and Pharmaceuticals

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Secondary Metabolites

• Secondary metabolites are those that are not essential for growth in pure culture.

• Believed to play an important role in competition among saprobes — invading or protecting substrates.

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Penicillium

• Ascomycota

• Ubiquitous in soil

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Alexander Fleming

Penicillin

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Staphylococcus “lawn”


Alexander Fleming

Penicillin

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Staphylococcus “lawn”

Vacation Time: took off August 1928


Alexander Fleming

Penicillin

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Staphylococcus “lawn” with mold growing on it. !Bacteria around mold dead.

Returned to lab September 3, 1928


Alexander Fleming

Penicillin

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Penicillium notatum


Alexander Fleming

Penicillin

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Mould juice aka

Penicillin


Penicillium griseofulvum: Griseofulvin

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Acremonium strictum: Cephalosporin

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Antibiotics

FUNGAL COLONY

INHIBITION ZONE

BACTERIAL GROWTH

• Metabolites that are toxic to other microbes

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Fungi and traditional medicine

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Fungi and Industry

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Composting

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Biopulping

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Biofuels

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Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 http://www.international.inra.fr/research/

“mold” fungus

Cellulose and hemicellulose hydrolysis by Trichoderma

reseii

Wood decay fungus

Break down of lignin by Pycnoporus cinnabarinus

Straw

WoodYeast

Sugar fermentation

ETHANOL

Biofuel production chain

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Industrial Mycology- enzymes, alcohol, citric acid

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UC Davis Phaff Yeast Collection

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Kyria Boundy-Mills


Novozymes in Davis

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Fungi and Ecosystems / Ecology

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Fungi Tolerance

• Many fungi can tolerate hypertonic environments (e.g., molds can grow on jelly in the refrigerator).

• Many fungi tolerate temperature extremes, as low as –6°C, and some tolerate temperatures above 50°C.

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Organic matter decay

• Fungi are very important for maintaining Earth’s ecosystems.

• Saprobic fungi (along with bacteria) are the major decomposers, contributing to decay of organic matter and recycling of the elements.

• Fungi are the principal decomposers of cellulose, lignin, and keratin.

• Without fungal decomposers, Earth’s carbon cycle would fail; carbon would be buried. 68


Fungi and Earth History

• During the Carboniferous period, saprobic fungi declined due to peat formation and acidification of swamps. Peat was eventually transformed into coal.

• At the end of the Permian, continents came together and volcanic eruptions triggered a mass extinction, but the fungi flourished.

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Figure 30.6 Fungus as Predator

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30.2 How Do Fungi Interact with Other Organisms?

Predatory fungi trap microscopic protists and animals.

Many secrete sticky substances so that passing organisms stick tightly to them. The hyphae then quickly invade the prey.

Some soil fungi make a constricting ring that can trap nematodes.

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