Download Marvellous Micro-Organisms - Dr Willa Huston

Marvellous Micro-organisms
Dr Willa Huston
[email protected]
What is a microorganism?

Microorganisms are forms of life requiring magnification to see and resolve
their structures.

"Microorganism" —bacteria, yeasts, molds, protozoa, algae, and
rickettsia—predominantly unicellular microbes.
Viruses are also included, although they cannot live or reproduce on their
own.

Microorganisms
 Bacteria
 Archaea
prokaryotic
microbes
 Virus
 Algae
 Fungi
 protozoa
eukaryotic
microbes
4 billion
years of
evolution
All life on earth until
approximately 600
million years ago or the
cambrian explosion –
multicellular forms
emerged
Currently unknown
biodiversity –
approximately 10
million species
A microorganism is an organism that is microscopic (usually too small to
be seen by the naked human eye).
Three Domains of Life
Cellular level differences
microbial
1M
eukaryotic
25M
Cann et al., PNAS 2008
How do microbes measure up?
Epulopiscium fishelsoni –
prokaryote (600 M)
Paramecium – eukaryote
(protozoan) (150 M)
Visualising Microorganisms:
Microscopy
Antonie van Leeuwenhoek, the first
microbiologist and the first to
observe microorganisms using a
microscope. 1675
Visualising Microorganisms
Bakers Yeast: Saccharomyces cerevisiae
Light microscopy
Phase contrast
microscopy
Dark field
microscopy
Bright field microscopy –
naturally pigmented
microbes
Fluorescent microscopy
Chlamydia
trachomatis
in human
cells
Transmission
electron
microscopy –
Bacillus subtilis
Scanning
electron
microscopy –
Rhodospirillum
sodomense
Microorganisms
Microorganisms
 Perform
 Pathogens
(lots egs to come)
 Important
to industry (lots egs to come)
important ecological functions
◦ Global biogeochemical cycles (such as
nitrogen cycles)
Microorganisms
Bacteria
 Symbionts
◦ Eg coral
endosymbiotic
relationship
with
photosynthetic
dinoflagellate
symbionts
(Symbiodinium
spp) (algae)
●up to 500 species normal oral flora
●easily be 25 species living in a single mouth
●a milliliter of saliva can contain as many as 40 million
(4 x 107) bacterial cells
●108 bacterial cells present in the cecum (initial part
of the colon) per milliliter of content is normal
●In a gram of soil, approximately 108 bacteria are
present11 and these are estimated to represent over
10,000 species.
● Interestingly, there are more than 1030 bacteria on
earth, compared with fewer than 1010 humans
Diversity of bacteria
Koch - Tuberculosis


1.
2.
3.
4.
1881; 1/7 deaths tuberculosis
Koch’s Postulates:
Organism must be present in
all cases of disease and absent
in healthy cases
Suspected organism should be
grown in pure culture
Organism should cause
disease in healthy animal
Organism should be isolated
from reinfected animal and
same as original organism
DOI: 10.1002/9780471729259.mc10a01s6
Archaea

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Unicellular
Prokaryotic (lack organelles and a nucleus)
Cell membrane completely distinct from bacteria and
eukaryotes (ether vs ester linked lipids)
Lack peptidoglycan
http://www.ucmp.berkeley.edu/archaea/archaeamm.html
Images supplied by: IW Sutherland
Deep Sea Thermal Archaea
Archaea
 Extreme
halophiles – high saline
environments eg great salt lake
 Methanogens – anoxic conditions
 thermophilic
Hot spring - Yellowstone
●120-50 °C
●Abundant in numerous
deep sea thermal vents
●Typical S-layer as for
archaea
●Anaerobic
heterotrophic sulphurand iron-reducing
thermoacidophile
Steam vent - Yellowstone
Reysenbach et al., 2006
Influenza A virus
Virus
oavian virus that has "recently" crossed into
mammals.
oBirds have the greatest number and range of
influenza
oAvian haemagglutinins sometimes appear in pig
human and horse trains
Ebola virus
HIV Virus
Algae
●Photosynthesis
●Organelles including nucleus and chloroplasts
●Great variety of structure, size, locations (freshwater,
marine), and pigmentation (mostly green, some red)
●Rigid cell walls
2005 estimated 38.6 million people
world-wide infected with HIV
TEM of T lymphocyte
producing HIV virus
Fungi
 No
chlorophyll
 Have organelles; including nucleus,
vacuoles and mitochondria
 Diverse habitats
 Rigid cell walls
 Moulds, yeasts, mushrooms
 Moulds- multicellular filamentous fungi
Aspergillus fumigatus
Can grow on hydrocarbons in aviation
kerosine
 Cellulytic
 Airborne spores can enter lungs and
wounds during surgical procedures

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Yeast
Slime moulds
Unicellular fungi
Budding process for replication (or sexual
reproduction) – fusion of two cells
Eg bakers yeast Saccharomyces cerevisiae
Eg Candida albicans – causes vaginal infections,
thrush, lung infections

Complex life cycle of different forms,
microscopic but eukaryotic organism
Dictyostelium
discoideum
http://www.rkm.com.au/FUNGI
/Candida.html
Protozoa

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Unicellular eukaryotic microorganisms
Lack cell walls
Ingest other organisms (including bacteria) or organics
Motile
Can cause diseases including trypanosomes – African
sleeping sickness
Malaria – Plasmodium vivax
http://www.wehi.edu.au/
wehitv/malaria/index.html
 300-500 million cases
world wide reported
annually
 Treatable and
preventable – however a
child dies every 30
seconds from it (mainly
in Africa)

Impact of microbes
Infectious Diseases
Yeast - Food
How is commercial yeast prepared by
industry?
Most important microorganism in food
production
 Alcohol fermentation
 Bread manufacture
 Source of vitamins, food and growth factors
 Preparation of bread

◦ Yeast is left with dough and sugar – converts the
sugar to alcohol and CO2 – the CO2 expands
causing the dough to expand. CO2 and alcohol are
backed off.
◦ Baking powder is a chemical source of CO2 – quite
a different product (used in some bread related
products)
Yeast – Alcohol Production

What makes yeast so versatile?
Naturally occuring yeast on
fruit has long been used to
ferment leading to alcohol
production
◦ Wine – grapes
◦ Beer – malted grains
◦ Spirits – distilled from
fermentation
◦ The type of wine is determined
by how much sugar is left
when the fermentation is
halted – and also how much
CO2 present (by conducting
final yeast fermentation in the
bottle this traps the CO2)
Yeast from inside a wine
bottle after 12 months
Wine yeast – Saccharomyces
ellipsoideus –
Flemming and Florey – Antibiotics
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Treatment of bacteria as infectious diseases was initially
trialled by chemical compounds (such as Salvarasan –
arsenic durb for syphilis, early 1900s)
Alexander Flemming noticed a mould (fungus) on his
bacterial plate cultures was killing nearby staphlococcus
(1929)
Howard Florey (and Ernst Chain) – developed a large
scale production of penicillin (1941)
Nobel prize shared in 1945
Bacteria - Bioremediation

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Degradation of herbicides, pesticides, oil, sewerage
Cleaning of industrial waste including mining waste
waters
Some bacteria can grow on alkanes and hydrocarbons
as their source of carbon and energy – they have been
shown to be capable of cleaning oil contaminated sea
water
International Biodeterioration & Biodegradation
Volume 50, Issue 1, July 2002, Pages 55-59
Bacillus licheniformis - subtilase
Food preparation – Louis Pasteur
Louis Pasteur defined ‘putrification’
prevented by heat sterilisation
 Described that fermentation leading to lactic acid and alcohol is
due to living organisms and not chemistry

 Naturally
occurring enzyme – protease
 >270 patents on this one enzymes for
changes to improve it’s properties
 Used in most laundry detergents which
claim to have enzymes


Recognised asymmetry in chemistry and life

living things mainly have L- rather than D form amino acids (due
to enzyme preferences), chemical generation leads to an equal
form of both (spontaneous generation theory debunked)
Developed Pasteurization (heating to kill most organisms) (not
sterilisation) – removes tuberculosis, brucellosis, Q Fever and
typoid fever from milk
 Most interested in wine and beer

Extremophiles – source of enzymes
for industry applications
This fungi found in the
warmest middle part of
compost is being tested to
find enzymes which could
improve landfill degradation
Biotechnology - an enzyme
which copies DNA and which
is widely used in diagnostics
and biotechnology to copy
DNA was first found in a
thermophilic microbe
(Thermus acquaticus)
Taq DNA Polymerase
Special Interest – Research
Infectious Diseases
Chlamydia
Legionella
http://brighamrad.harvard.edu/Cases/bwh/images/56/
R18HSG2.GIF
Any Questions??
Sources:

Brock, Biology of Microorganisms, Prentice and Hall

http://web.uct.ac.za/depts/mmi/jmoodie/influen2.html

http://www.biology.ed.ac.uk/research/groups/jdeacon/microbes/thermo.htm
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A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents; Anna-Louise Reysenbach, Yitai
Liu, Amy B. Banta, Terry J. Beveridge, Julie D. Kirshtein, Stefan Schouten, Margaret K. Tivey, Karen L. Von
Damm and Mary A. Voytek Nature 442, 444-447(27 July 2006)
http://darwin.nmsu.edu/~molb470/fall2005/projects/pan/images/PhylogeneticTreeOfLife.jpg

http://catalogue-of-organisms.blogspot.com/2008/09/diversity-of-slime-moulds.html
http://www.google.com.au/imgres?imgurl=http://www.biology.ed.ac.uk/research/groups/kmatthews/pix/lifecy
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