Chapter 01 - Science of Microbiology

8/2/2019 Chapter 01 - Science of Microbiology

1/36

Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies

Chapter 1Chapter 1

The Science of MicrobiologyThe Science of Microbiology

BIO 2924BIO 2924


2/36

Ancient history! Bacteria

Put the first molecular oxygen in the earthsatmosphere, creating the ozone layer that

protected Earths surface from killing

radiation.

Created conditions permitting the later

evolution of oxygen-utilizing creatures such

as us.

Have a varied metabolic capabilities that

allowed them to survive under an impressive

variety of conditions.


3/36

They learnt to maximize modify their genome

(DNA) thereby creating new capabilities thatenabled them to colonize many niches onEarth.

No part of Earth has been found free of bacteria from the arctic ice to the deep subsurface ofland masses, from the depths of oceans toboiling hot springs.

They are specialists in metabolic diversity. Eukaryotes generally expand their metabolic

diversity by acquiring bacteria or archaea as

ENDOSYMBIONTS

Never Underestimate the Power of Bacteria


4/36

Recruiting Endosymbionts

Plants acquired photosynthetic bacteria that later

modified into chloroplasts. Root nodules of legumes have bacteria that can fix

atmospheric nitrogen, making the plant self-fertilizing.

Animals recruited bacteria and archaea to colonize

their intestinal tracts for protective or nutritional

reasons.

Ruminants (e.g., cattle, goats) rely on ruminal

bacteria to digest grasses and other forages. No single bacterial species that is essential to man.

- Picture of the Bubble Boy Page 483


5/36

1.10

figure 01-10.jpg

NATURES EVOLUTIONARY GAME PLAN

PROKARYOTESPROKARYOTES

EUKARYOTESEUKARYOTESFormerly known

as Archaebacteria

Bacteria and archaea were the first life forms to appear, about

3.5 4 billion years ago, and ruled undisputed for a billion

years before the first eukaryotes appeared on ancient earth.


6/36


The Scope of Microbiology

Seven divisions of Classification

1. Bacteria: Prokaryotic

2. Archaea: Prokaryotic

3. Algae: Eukaryotic

4. Fungi: Eukaryotic

5. Protozoa: Eukaryotic

6. Viruses: Acellular7. Helminths: Eukaryotic

Prokaryotic: before a nucleus

Eukaryotic: true nucleus


7/36

Microbiology The study of Microorganisms (microbes) Cannot be seen by the unaided eye Prokaryotes Before a nucleus lack a nucleus Eukaryotes After a nucleus blessed with a nucleus!

7 divisions of Classification

1. Eubacteria (Modern Prokaryotes) 1/1000th the size of a eukaryotic cell Mostly unicellular Different shapes and sizes Can grow at varied temperatures (-20oC to 110oC) Can withstand extremely acidic to alkaline conditions Autotrophs, decomposers Vast spectrum of diseases important uses


8/36

2. Archaea (Ancient Prokaryotes) Initially Archaebacteria

Hostile environments, Extreme heat, high acidity, highalkalinity, high salt concentration E.g., Methanogens (not human pathogens)

3. Cyanobacteria (Prokaryotic) & Algae (Eukaryotic) plant-like, photosynthesis Unicellular microscopic to multicellular macroscopic Critical to global ecology, negligible medical importance

4. Fungi (Eukaryotic) Nonphotosynthetic, mostly multicellular Mostly scavengers, decompose dead organisms Mostly responsible for plant diseases

Corn smut, wheat rust economically important Some human diseases

Pneumocystic pneumonia in AIDS patients(Pneumocystis carinii), Hallucinations (Amanita)



9/36

5. Protozoa (unicellular) parasitic diseases motile, animal like, complex architecture

E.g., amoeba, flagellates, ciliates malaria, sleeping sickness: Parasitic diseases

6. Viruses (plant, animal or bacterial) - Acellular DNA or RNA wrapped up in a protein coat 1/1000th 1/10th size of bacteria: Electron Microscope E.g., virions, prions etc Cannot reproduce outside of host cell. Cause of smallpox, yellow fever, polio, AIDS, common

cold, flu, ebola, etc

PRION: scrapie (sheep), mad cow disease, CJD (human)7. Helminths (multicellular) Parasitic diseases

Worms macroscopic, microscopic. Belong to the animalkingdom

Flatworms (beef tapeworm, liver trematodes) Roundworms (hookworms, trichinella)



10/36


A Brief History of Microbiology

Bubonic Plague orBlack Death: 25 million casualties

in the Europes Middle ages (1347 lasted 20 years) Causative organism Yersinia pestis (Y. pestis)

Yersinia infested fleas, whose hosts were rats.

Rats died, and the bacterium spread to humans.

Disease causes subcutaneous hemorrhaging, and

spots of blood which turn black, to accumulate

under the skin

Buboes swollen lymph nodes Buboes often become open sores

Can also affect the lungs pneumonic plague

Still found among squirrels in parts of the U.S.


11/36


Buboes in Fig 1 & 2: Swollen lymph nodes

Black spots formed due

to hemorrhaging

Fig 1 Fig 2


12/36

A Brief History of Microbiology

Childbed fever (Puerperal fever) (Mid 1800s) Caused by the bacteriumStreptococcus pyogenes Symptoms: fever, chills, delirium and death In the past centuries, it was the greatest killer of

women. One sixth of women died of this fever

Caused by infection of the genital tract shortly aftergiving birth (latin puer child). Any fever within 2weeks of childbirth is dangerous since it can causeinfertility and septicemia ( presence of infectious

microbes in the bloodstream, causing sepsis) Ignaz Semmelweis showed that sanitary

techniques virtually eliminated puerperal fever inhospitals. He used chlorine as a disinfectant

He was treated with skepticism and ridicule


13/36


A Brief History of Microbiology The Great Irish Famine (1845 1849)

Potato blight that led to the death of >106 people

caused by the potato fungus orPhytopthora

infestans

Potatoes infected with late blight are shrunken on

the outside, corky and rotted inside

Photo by Scott Bauer.


14/36


Brief History of Microbiology

1674 Leeuwenhoek: sees microorganisms

1796 Jenner: vaccine for smallpox 1847 Semmelweiss: cause of childbed fever 1859 Pasteur: disproves spontaneous gen.

1865 Lister: introduces antiseptic technique 1876 Koch: pure culture on agar/Postulates 1892 Iwanowski: discovers viruses 1894 Ehrlich: selective toxicity (Salvarsan) 1929 Fleming: discovers penicillin 1977 Woese: classifies Archaea 1982 Stanley Prusiner discovers prions

1983 Luc Montaigner , HIV/AIDS


15/36

Advances in Microbiology Robert Hooke - 1665

Coined the word cell after Looking at cork slices

Schleiden & Schwann - Came up with the Cell theory- cell is the basic unit of living beings- All cells arise from preexisting cells

Anton Von Leeuwenhoeks Animalcules 1674A draper with very little schooling. Later he wasappointed janitor at the Delft City Hall in Holland.

Best lens maker of his time! His hobby was making

little glass lenses. Peter the Great paid his respects. He was the first to see blood moving thru capillaries In 1680, was elected a Fellow of the Royal Society. Kept detailed notes and sketches. Published over

400 scientific papers. Ground 419 lenses in his life.

Ad i th G Th f Di


16/36

Advances in the Germ Theory of Disease

Ignaz Semmelweis 1847

Physician in obstretrics ward of a Vienna hospital Maternity patients contracted blood-poisoning

from doctors who also handled corpses at the

morgue and didnt wash their hands before

handling maternity patients Proved that hand washing with Chlorine cut

down the mortality rate of childbed fever

His doctrine was dismissed by most doctors! Interestingly

The same bacterium also causes scarlet fever


17/36

The Middle Ages: Microbiologys Dark Age!

Transition period: Microbiology had no focus during

this period, several flawed theories held sway! Miasmatic theory of disease: Diseases such as

cholera and the black plague were caused by amiasma (Greek, pollution), or bad air.

Cholera was believed to be spread through air,because it was epidemic in places where the waterwas stagnant and foul smelling.

Theory of Spontaneous Generation (Abiogenesis) The belief: complex living organisms arise

spontaneously from decaying organic substances Eg: maggots spontaneously appear in meat, mice

from dirty hay, and fleas from putrid matter.


18/36


Microbiology Dark Ages!

John Needham (British Clergyman)did experiments

with meat broth that he felt supported spontaneousgeneration.

Francesco Redi proved that no maggots appeared

in meat when flies were prevented from laying eggs

Spallanzani showed that microbes came from air,and could be killed by boiling

meat broth that is boiled in a sterile environment

stays uncontaminated Despite these great experiments, the supporters of

spontaneous generation were not convinced.


19/36

Louis Pasteur(French Scientist) 1822 - 1895

Also known as the Father of Microbiology

Ushered in the golden age of Microbiology, with 2

important areas of research:

Definitively disproved Spontaneous Generation byhis famous Swan Necked Flask Experiment

Invented the Germ Theory of disease germs,

and not bad air cause disease Best known for showing how to stop milk and wine

from going sour Pasteurization

Created the first vaccine for rabies

Spontaneous Generation Proven Wrong


20/36


Pasteur demonstrated that fermentation is caused by

the growth of microbes in nutrient broth, and thegrowth of microbes in nutrient broths is not due to

spontaneous generation.

He exposed boiled broths to air in vessels where air

was admitted via a long tortuous tube that would notallow dust particles to pass because of its shape and

thinness. Nothing grew in those broths.

The living organisms that grew in those broths camefrom outside, as spores on dust, rather than by

spontaneous generation.

Louis Pasteur and the Germ Theory


21/36


The Swan Flask made by Pasteur

All the germs (spores

etc) settle here and dontenter the flask

The broth, that has

been boiled in this flask,stays uncontaminated. It

will get contaminated

only if the flask is tilted

and the liquid allowed tocome in contact with the

spores that have settled

in the region shown

above


22/36

Boiled meat in a Swan necked flask that allowed air

but not microorganisms Proved that microorganisms causes the broth to

spoil.

Swan Necked Flask Experiment


23/36

Louis Pasteur

18221895

Disproved

Spontaneous

GenerationFermentation

Silkworm disease

Pasteurization

Developed vaccines

Chicken choleraAnthrax

Rabies

Immunity


24/36

Immunity Stimulation of the bodys defense mechanism to

combat and ward off infection.

Edward Jenner-1749-1823 Observed that the dairymaids who naturally

contracted a mild infection of cowpox were immuneto smallpox

Inoculated fluid from cowpox blisters from adairymaid into an 8 year old boy (James Phipps) ofa local farmer. The boy contracted cowpox.

The boy was inoculated with fluid from a smallpox

blister. Showed no signs of smallpox (immunity!) Vaccination (latin vacca = cow) The Turkish inoculation practice: Circassian

method of inoculation had been followed for

centuries Lady Mary Montagus letters


25/36

Cause and Effect in Infectious Disease

Research By 1800s: Microbiologists struggled to identify

microbes that cause diseases like Cholera and TB

Disease can be caused by microbes too small to be

seen? Yeah right!

Robert Koch 1876 Infectious disease research needs a rigorous

scientific basis.

Proposed 4 criteria for establishing a cause andeffect relationship between microbe and disease

- KOCHS POSTULATES

Used agar to obtain pure cultures of microbes


26/36


Robert Koch

18431910

Developed techniques

for culturing bacteria in

the laboratory

Developed steam

sterilization

Etiology of anthrax,

cholera, tuberculosis,

sleeping sickness

Kochs postulates

I k h t t ! C d Eff t


27/36

I know what youre up to!: Cause and Effect

Robert Koch (German Scientist)

1. Isolated anthrax bacillus from dead cows2. Cultured them in nutrient broth

3. Intentionally injected the cultured bacilli into

mice. Mice died.

4. Isolated and cultured anthrax bacilli from dead

mice tissues.

Also famous for developing pure culture

techniques for isolating and growing bacteria Used agar for the first time to grow colonies

(clones) of bacteria on solid media

Obtained the agar from his neighbours pantry

KOCHS POSTULATES


28/36

KOCHS POSTULATES

1. Microbe must be associated with disease-lesions found in diseased but not healthy tissue

2. Microbe must be isolated from disease-lesions as apure culture

3. Pure culture of the microbe should cause diseasesymptoms if inoculated into humans or animals

4. Microbe must be re-isolated in pure culture fromhumans or animals used to satisfy the 3rd postulate.Invaluable for proving that a specific disease iscaused by a particular microbe

5. Led to the isolation of almost all bacterial diseasesprevalent in Europe (typhus, dysentery, syphilis,gonorrhea, pneumonia etc)

1. Koch himself identified the rod shaped bacteriumMycobacterium tuberculosis that causes TB.

Preventing Microbial Attack!


29/36

Preventing Microbial Attack! Sir Joseph Lister(British Surgeon)

Aseptic technique

- Surgery mortality from 70% - 15%.- Use of Phenol as a disinfectant.

Alexander Flemming

The first chemotherapeutic agent, Penicillin.Antibiotics: produced by microbes

Paul Ehrlich

Stained the bacterium of tuberculosis Discovered the dye Trypan Red that destroyed

trypanosomes heralded the era of chemotherapy

Microbiology in the Modern Era


30/36

Microbiology in the Modern Era

Paul Erlich: Selective toxicity. Salvarsan was usedto treat syphilis

Sulfa drugs (first chemotherapeutic drugs) WW1Antibiotics Widespread clinical use was in1950s

Immunology Virology

Iwanowsky discovered TMV Viruses much smaller than bacteria. Seen via EM Filtration can separate viruses from bacteria

Genetic Engineering Cloning: insulin production in E. coli

Environmental Microbiology: Bioremediation (cleaning up the environment using

microbes that degrade toxic chemicals)

Emerging and Re emerging Infectious Diseases


31/36

Emerging and Re-emerging Infectious Diseases

The first cracks in the protective shield against

microbes began to appear in the 1980s. Old standbys

like penicillin were no longer fully protective. By 1995, infectious diseases became one of the top

five causes of death in the United States

Disease patterns change Bacteria change

Human activities change creating new opportunities

for bacteria to cause disease

Foodborne and waterborne illnesses

Nosocomial infections

Bioterrorism

Antibiotic resistance


32/36

Waning bacterial diseases

Syphilis

FIELDS IN MICROBIOLOGY

Medical microbiology

Environmental microbiology

Industrial microbiology

Agricultural microbiology

Look up Table 1.1 (important)

Submerging Infectious Diseases

Disease Definition Examples


33/36

DiseaseCategory

Definition Examples

New-new New diseases caused by newlydiscovered bacteria

Lyme disease

Legionnaires disease

New-old Diseases caused by newlyrecognized pathogens that havebeen around for long

Campylobactefoodborne disease

Old-new Old diseases that havereappeared

Long-known pathogensacquiring traits that make themmore dangerous

TB, Cholera, Diphtheria

Antibiotic resistantbacteria

Old-old Old diseases with known

causes being recognized now

C. trachomatis

gonorrhea

Some Examples of Bacterial


34/36


Some Examples of Bacterial

Shapes

SpiralSpiral CoccusCoccus

FlagellateFlagellate

G th A C t i i P t i Di h


35/36


Growth on an Agar Containing Petri Dish


36/36

Opalescent Pool in Yellowstone National Park, Wyoming USA. K.

Todar. Conditions for life in this environment are similar to

Earth over 2 billion years ago. In these types of hot springs, the

orange, yellow and brown colors are due to pigmented

photosynthetic bacteria which make up the microbial mats. The

mats are literally teeming with bacteria. Some of these bacteriasuch asSynechococcus conduct oxygenic photosynthesis, while

others such as Chloroflexus conduct anoxygenic photosynthesis.

Other non-photosynthetic bacteria, as well as thermophilic and

acidophilic Archaea, are also residents of the hot spring

i

Date post:	05-Apr-2018
Category:	Documents
Upload:	studentdoc2014
View:	223 times
Download:	0 times

Chapter 01 - Science of Microbiology

Documents