Lecture 1 Micro Introduction Copy

8/6/2019 Lecture 1 Micro Introduction Copy

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Dr. Rose Elaine D. Tan

INTRODUCTION TO MICROBIOLOGY


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What is Microbiology?

Micro - too small to be seen with the naked eye

Bio life

ology - study

Definition Microbiology branch of biology which deals with the study of minute

living microorganism not visible to the naked eye andtheir effects on other living organisms


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Microorganisms included :

1. Bacteria - simple, single cell

2. Fungi - single & multi cell forms

- yeast, filamentous molds, complexfungi

3. Protists - single cell, some multicellular

- algae, protozoans, slime molds

4. Viruses - acellular, intracellular parasites

5. Parasites - multicellular, more complex


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Bacteriology - study of Bacteria- Group of microscopic, single-celled organisms

that inhabit virtually all environments, includingsoil, water, organic matter, and the bodies ofmulticellular animals.

Phycology - study of Algae

Virology - study of Virus Mycology - study of Fungi

Parasitology - study of Parasites

Immunology - study of cells, molecules and mechanisms

responsible for immunity

Scope of Microbiology


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Health related:

1. Etiology identification of causative agent ofdiseases

2. Epidemiology study of spread of disease

3. Immunology study of immune system

4. Chemotherapy treatment of disease with

chemical compounds

5. Infection control control of spread of infectious

diseases


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A. Causative agents of infectious diseases and food

poisoning (Pathogenic Organisms)

B. Normal flora/Microbiota: - microorganisms that arenormally found on or in the body and do not causedisease

1. Beneficial metabolic functions

2. Prevents invasion of pathogens and over growth ofpotential pathogens

3. Normal flora vs. identification pathogen

BENEFICIAL APPLICATIONS

(WHYSTUDYMICROBIOLOGY ?)


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C. Environmental importance

1. Bacteria act as decomposers and produce oxygen2. Food chain

3. Sewage treatment

D. Industrial Importance

1. Food and Brewing industry- involved in the production of vinegar, cheese, bread,

beer, and wine

2. Pharmaceutical industry

- Probiotics - are dietary supplements of live beneficialbacteria (Lactobacillus & Bifidobacterium) oryeast which confer a health benefit on the host

- Antibiotics

- Produce industrial chemicals such as ethanol andacetone


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E. Bioremediation clean up technology that uses naturally

occurring microorganisms to degrade or neutralize

hazardous substances into non/less toxic compounds in

polluted soil or water

- Exxon Valdez oil spill - 1989

- 2 Genera: Pseudomonas sp. & Bacillus sp

F. Biotechnology: Recombinant DNA Technology, Gene Therapy,and Genetic Engineering

- bacteria & fungi can be manipulated to produce

enzymes and proteins they normally would not produce- Ex. Insulin, Human Growth Hormone, Interferon

Vaccines and Antibiotic

G. Research


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BRIEF HISTORYBRIEF HISTORY

before microorganism were discovered, ancient peopleregarded diseases as a form of punishment sent byGOD for the sins of men

Biblical disease - Leprosy- Tuberculosis

- Syphilis

- Plague

treatment and prevention of these diseases were sought bysacrifices to appease the anger of God


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Marcus Terentius Varro during the 2nd century B.C postulated the

concept of contagion

q

diseases are transmitted by invisible creature

In De re rustica, a book on agriculture, he speculatedthat contagion from stagnant water might affect aperson's health.(This theory of disease was first formulated scientificallyin 1546 by Girolamo Fracastoro.)


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Girolamo Fracastoro (1546) Latin Hieronymus Fracastorius

He is best known for Syphilis

His intense study of epidemic diseases led to his book

On Contagion and Contagious Diseases

He postulated that each disease is caused by a differenttype of rapidly multiplying minute body (invisible livingthings), transmitted by direct contact or by intermediary

inanimate fomites or through the air.


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Roger Bacon (13th century) postulated that invisible living creatures calledgerms produce disease

He constructed the first magnifying lenses in 1267 Useful to enlarge detail on small organisms


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Anton Van Leeuwenhoek

Father of Bacteriology 1st to describe bacteria in 1677

with the use of a simple microscopeutilizing crude lenses

1stperson to actually see live microorganismsanimalcules that he observed in teeth scrapings,rain water, and peppercorn infusions

Submitted detailed descriptions and drawings to theRoyal Society of London

described the 3 major forms of bacteria(rod, spherical, spiral) andfungi, protozoa, spermatozoa


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Robert Hooke (1665)

developed the compound microscopethat used reflected light and was ableto confirm Leeuwenhoeks discoveries

Founded the field of Microscopic

Biology through his published work -"Micrographia

first person to coin the word cell todescribe the tiniest components of the

living system


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ABIOGENESIS

THEORY

VS

BIOGENESIS

THEORY

The discovery of microbesboth generated and spurredenough interest not only inthe fundamental origin ofliving things but alsoaugmented argument andspeculations alike


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(Abiogenesis)(Abiogenesis)

This theory existed to explain the origin of some formsof life

Living organisms arose spontaneously from nonliving,decaying organic matter.

Believed to explain the origin of animalcules

Spontaneous generation theory took another 200 yearsto disprove


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Aristotle

proposed theSpontaneous Generation Theory

living things could developspontaneously from non-living

materials Supported by appearance of living

creatures in decaying meat,stagnating ponds, fermenting grain,and infected wounds


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Experiments to disproveExperiments to disprove

Spontaneous Generation TheorySpontaneous Generation Theory

1. Francesco Redi (1626-1697)

Introduced experimental procedure for disproof S.G

Utilized jars containing meat. Some were covered,some were not.

he challenged the idea that maggots arosespontaneously from rotting meat

Results not accepted for microscopic organisms.


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1. Unsealed demonstrated the appearance ofmaggots in decomposing meat as a result on thedeposition of eggs by flies

2. Sealed no maggots on meat

3. Partially covered -- realizing that the sealed containerswere deprived of air, he used "fine Naples veil", andobserved no worm on the meat, but they appeared onthe cloth


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2.John Needham (1713-1781)

claimed that vital life is needed for the spontaneousgeneration of microbes

Introduced the first culture medium for microbial growthutilizing infusion broth prepared by boiling meat & grain, toextract nutrients.

Broth put in flasks, some were sealed with corks, some werenot.

Believing that boiling would kill all living things, he showedthat when sealed right after boiling, the broths would cloud,allowing the belief in spontaneous generation to persist

He added that the reason why no living organisms emergedfrom heated and sealed solutions in containers is that thevital life was destroyed by the heat and new vital life wasnot supplied to the solutions because they cannot enter thesealed containers


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3.Lazzaro Spallanzani (1729-1799)

Repeated Needhams experiments but attempting to excludethe possibility of introducing a contaminating factor betweenboiling and sealing

Broth is boiled after placing in sealed flasks.(done by melting neck of the flask)

Although he did not see growth, the exclusion of air left thequestion of whether air was an essential factor inspontaneous generation

Results more consistent with Redis

Occasionally sealed flask p cloudy


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4 . Rudolph Virchow

in 1858, he challenged the spontaneous generation withhis concept/theory of biogenesis.

He claimed that living cells can arise only frompreexisting living cells

This concept would somehow explain the origin ofanimalcules seen under a microscope.

Although Virchow was correct with this concept, helacked the needed experimental evidences demonstrating

his concept of biogenesis.


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5. John Tyndall

proved that dust carried germs

also found out that bacterial spores could be killed bysuccessive heating

tyndallization (Fractional sterilization) - heating withfree -flowing steam for 30-60min for 3 consecutive days

at100rC


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6. Louis Pasteur

Placed boiled infusion broths in swan-necked flasks Flasks remained sterile unless tilted or neck broken

The idea being that the bend in the neck prevented anyparticles from reaching the broth, while still allowing thefree flow of air. The flask remained free of growth for anextended period.

When the flask was tilted so that particles could fall downthe bends, the broth became quickly clouded suggestingbacterial contamination


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His experiment was accepted as disproof of theory of SG.Thus he claimed the prize for the contest conducted todisprove the spontaneous generation theory in 1864

Additional work:

Pasteurization - to prevent spoilage of wine.

Introduced Germ Theory of Disease after discoveringsilk worm disease caused by protozoan.


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The Theory of BiogenesisThe Theory of Biogenesis

states that living things can only arise from living thingsand cannot be spontaneously generated

Virchow introduced the Theory of Biogenesis attributed to Louis Pasteur - He provided the evidence

that any appearance of spontaneous life in nonlivingsolutions can be attributed to microbes that already exist

in the air or in the fluids themselves. Pasteur's (and others) empirical results were summarized

in the phrase, Omne vivum ex vivo, Latin for all life[is] from life


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Germ Theory of DiseaseGerm Theory of Disease

developed by Louis Pasteur

it states that each specific infectious disease is caused by a

specific microorganism

Scientists hypothesized that since microorganisms have theability to modify non-living organic matter, they may alsohave the ability to do the same in living plants and animals that the modifications (whether physical or chemical)they made to these organisms are the causes of disease.They later called this hypothesis as the germ theory ofdisease


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Important Events That Strengthened the GermTheory

1.Louis Pasteur (1865)

was able to prove that the new silk worm disease

affecting the silk industry was caused by a protozoan. He formulated a way to identify afflicted silkworm

moths so that they would be destroyed and would notinfect others.

He proved that the invisible protozoans cause diseaseto the silk worms.

Note that the invisibility of the protozoans is due totheir very tiny sizes (a few micrometers) which can onlybe seen under a microscope


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2.Joseph Lister (1878)

used the germ theory of disease to promote his idea thatdisinfection is necessary to prevent the spread ofdiseases caused by microorganisms

He promoted carbolic acid (phenol solution) as the

disinfectant, knowing that it effectively kills bacteria. When surgeons found out that the phenol solution has

dramatically reduced the incidence of infections anddeaths to patients, more doctors began using it until itbecame a standard operating procedure.

also developed the first pure culture technique usingliquid medium which was the key to identification ofbacteria


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3. Robert Koch

first scientist to devise a series of proofs used to verifythe germ theory of disease

used the germ theory of disease to prove that thedisease anthrax, which kills cattle and sheep, is caused

by a bacterium Kochs Postulates - sequence of experimental procedures

for directly associating a specificmicroorganism to a specific disease

Established proof of the microbial etiology of 3 importantdiseases of this day: Cholera (V. cholerae) Tuberculosis (M. tuberculosis)Anthrax (Bacillus anthracis)


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(Postulate 1)The organism must always

be found in diseased animalsand not in healthy one

(Postulate 2)Organisms isolated from

the diseased animals mustbe grown in pure cultureaway from the diseased

animals

(Postulate 3)Organisms grown in pureculture must initiate andreproduce the disease when

re-inoculated into susceptible animal

(Postulate 4)Organisms must be

re-isolated fromexperimentally

infected animals

KOCKS POSTULATE


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Exceptions to the Kocks Postulate :

#1) Carrier - some individual harbors the organism but donot manifest the disease and can transmit thedisease to others

# 2) Some or certain organisms/bacteria cannot be cultured

in vitro (cannot grow in artificial culture media)Ex. Mycobacterium leprae / Treponema pallidum

# 3) Certain animals not susceptible to certain microorganism- some animals are by nature immune

cannot replicate even with the same specie

- some bacterial specie are host specificEx. Vibrio cholerae cannot cause chicken

cholera or vice versa


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The Golden Age of MicrobiologyThe Golden Age of Microbiology

18571857--19141914

Period (about 50 years) of rapid development.

Causes of diseases identified, control methods developed,

work began on viruses

Beginning with Pasteurs work, discoveries included therelationship between microbes and disease, immunity, andantimicrobial drugs

Edward Jenner

Developed small pox vaccination utilizing vacciniavirus.


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Robert Koch

While studying anthrax ( a disease of cattle) Identified a bacterium as cause of anthrax (first

bacterium that caused a disease).

Introduced solid medium using agar.

Observed differences in colony morphology. Introduced the inoculating loop to transfer bacteria

and prepare pure cultures.

Introduced Kochs Postulates and the concept that

a disease is caused by a single organism.

Joseph Lister (1865)

Introduced the antiseptic technique.

Use of phenol (carbolic acid) as disinfectant.


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Martinus Beijerink (1884-1885) Discovered filterable agents called viruses

(latin for toxins, poisons). Infectious agents in tobacco plant fluidAssumed soluble toxin in filtrate caused disease

Paul Ehrlich (1912)

Introduced concept of chemotherapy. Use of salvarsan for the treatment of syphilis.

Alexander Fleming (1928)

Discovered the first antibiotic penicillin.

Produced by mold that contaminated bacterialculture plate.

Led to discovery of other fungi that secretedantibacterial substances (antibiotics)


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Carl Linnaeus- the Father of Taxonomy- His system for naming, ranking, &classifying organisms is still in wide use- He established the system of scientificnomenclature: Genus & specie


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MICROBIAL TAXONOMYMICROBIAL TAXONOMY

area of biologic science comprising of 3 distinct but highlyinterrelated disciplines that include:

- Classification

- Nomenclature

- Identification

1. Establish phylogenic relationships between groups oforganisms

2. Provides reference for identification by describingphysical, chemical characteristics of previouslyidentified and classified organisms

3. Provides universal language of communication


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ClassificationClassification

organization or level of classification of microorganismsthat share similar morphologic, physiologic and genetictraits into specific groups or Taxa / Taxon

Genus: comprised of different species that have severalimportant features in common but differsufficiently to still maintain their status as individualspecie

Species: most basic taxonomic group and may bedefined as a collection of bacterial strains that sharemany common physiologic and genetic features and

as a group differ notably from other bacterial specie


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Hierarchical: broad divisions are

divided up into smaller divisions:

Kingdom

Phylum

Class

Order

Family

Genus

Species

Modern Taxonomy


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IdentificationIdentification

process by which a microorganisms key features aredelineated

the profile is compared with those of other previouslycharacterized microorganisms so that the organism inquestion can be classified within the most appropriatetaxa and can be assigned an appropriate Genus andSpecies name


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General categories of identification method: Genotypic characteristics

Relate to an organisms genetic make-up including thenature of the organisms genes and constituent nucleic acid

Phenotypic characteristics

includes readily observable characteristics

Morphology, staining reaction, antigenic properties,environmental & nutritional requirements, resistance

profiles


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NomenclatureNomenclature

Scientific name (Systematic Name)Binomial System of Nomenclature

first letter of the genus name - always capitalized

first letter of the species name - small letter genus name may be used alone to indicate a genus group

a species name is never used alone

Genus and species are either:

underlined: Escherichia coli

italicized: Eschericia col

Abbreviated: E. coli


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- before microorganisms were discovered allliving things were believed to be either

plants and animals

- no transition type were thought to exist

- after discovery of microorganism it was clear that microorganism combines

both plant and animal properties


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Linnaeus1735

2 kingdoms

Haeckel1866

3 kingdoms

Chatton1937

2 empires

Copeland1956

4 kingdoms

Protista Prokaryota Monera

Vegetabilia Plantae Eukaryota Protista

Animalia Animalia Plantae

* Proposed Animalia

Evolution of Taxonomy


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Whittaker

19695 kingdoms

Woese et al.

19776 kingdoms

Carl Woese

et al.1990

3 domains

Monera Eubacteria Bacteria

Protista Archaebacteria Archaea

Fungi Protista EukaryotaPlantae Fungi

Animalia Plantae

Animalia


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is a branching diagram showing the inferred evolutionary relationshipsamong various biological species or other entities based upon

similarities and differences in their physical and/or geneticcharacteristics.

The taxa joined together in the tree are implied to have descended

from a common ancestor.


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EUCARYOTES higher protists

ex: algae

red algae, brown algae green algae

fungi Protozoan slime molds


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EUKARYOTES

Eukaryotes may more formally be referred to as the taxonEukarya or Eukaryota

Possess a true nucleus.

a. Nuclear material surrounded by a nuclear membrane.

b. contain the genetic information of the cell inmultiple strands of DNA and proteins (chromosomes)

c. Nucleus contains nucleolus - sites of ribosomesynthesis

Cell wall - Occur only on plant cells, fungi ; Composed ofcellulose, chitin.

cell membrane regulates flow of material in and out of thecytoplasm


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cytoskeleton which provides support for the differentorganelles

- contain complex phospholipids, sphingolipids, histones,sterols

mitochondria are sites of energy production for cellularwork

ribosomes (80s) - masses of RNA and proteins thatfunction as the site for protein synthesis

golgi apparatus is where protein is packed for export

endoplasmic reticulum is involved in the transport ofnewly synthesized proteins

lysosomes are vesicles that contain enzymes for cellulardigestive process


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method of cell division: mitosis

mitosis - one cell divides to produce two geneticallyidentical cells

meiosis - which is required in sexual reproduction,one diploid cell (having two instances of each

chromosome, one from each parent) undergoesrecombination of each pair of parental chromosomes,and then two stages of cell division, resulting in fourhaploid cells (gametes)


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PROKARYOTES

lower protists

Are organisms that lack a cell-nucleus, or any othermembrane-bound organelles

Most are unicellular Prokaryotes belong to two taxonomic domains:

Bacteria

Archae (Archaebacteria)

Methanogen

extreme halophiles

thermoacidophiles


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Characteristics:

lack a nucleus or nuclear membrane

ribosome (70s)

absent mitochondria

have no organelles, histones and

only in rare cases complex phospholipids, sphingolipidsand sterols

chemical activities takes place in the cytoplasm

have a cell wall composed of peptidoglycan withmuramic acid


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are haploid with a single chromosome composed solelyof DNA

method of cell division: binary fission

- is a form of asexual reproduction and cell divisionused by all prokaryotes, some protozoa, and some

organelles within eukaryotic organisms.

- This process results in the reproduction of a livingprokaryotic cell by division into two parts that eachhave the potential to grow to the size of the originalcell.

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