micro introduction

8/8/2019 Micro Introduction

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Dr. Rose Elaine D. Tan

INTRODUCTION TO MICROBIOLOGY



What is Microbiology?

y Micro - too small to be seen with the naked eye

y Bio life

y ology - study

Definition Microbiology

y branch of biology which deals with the study of minute

living microorganism usually not visible to the naked eye



Scope of Microbiology

Bacteriology study of Bacteria

Phycology study of Algae

Parasitology study of Parasites

Mycology study of Fungi

Virology study of Virus

Immunology study of cells, molecules andmechanisms responsible for immunity



Bacteria - what comes to mind?y Diseases

y Infections

y Epidemics

y Food Spoilage

y Only 1% of all known bacteria cause human diseases

y About 4% of all known bacteria cause plant diseases

y 95% of known bacteria are non-pathogens

y Normal microbiota/flora: microorganisms that arenormally found on or in the body and do not cause disease

y Pathogen: a microorganism that causes disease



Application of Microbiologyy Food production (vinegar, cheese, bread, beer, wine)

y Probiotics are dietary supplements of live bacteria(Lactobacillus & Bifidobacterium) or yeast which confer a health benefit on the host

y Produce industrial chemicals such as ethanol and acetone

y Bioremediation clean up technology that uses naturallyoccuring microorganisms to degrade hazardoussubstances into non/less toxic compoundsy

Exxon Valdez oil spill - 1989y 2 Genera: Pseudomonas sp. & Bacillus sp.



y

Insect Pest Control- Using bacteria to control the growth of insects(Bacillus thuringiensis)y caterpillarsy bollwormsy corn borers

y Recombinant DNA Technology, Gene Therapy, Genetic Engineeringy a new technique for biotechnologyy Bacteria & fungi can be manipulated to produce enzymes and

proteins they normally would not producey Insuliny Human Growth Hormoney Interferony Vaccinesy Antibiotic



BRIEF HISTORY

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

y disease were not new to man

y Biblical disease - Leprosy

- Tuberculosis

- Syphilis

- Plague

y treatment and prevention of these diseases were sought by sacrifices and lustration to appease the anger of God



Varro = during the 2nd century B.C. postulated the

concept of contagionq

diseases are transmittedby invisible creature

Roger Bacon (13th century) = postulated that invisibleliving things called germs produce disease

Fracastorius (1546) = postulated that disease iscaused by invisible living things and can betransmitted by direct contact (person to person contact)



Spontaneous Generation Theory

y Aristotle proposed the

Spontaneous Generation Theory

y Also called Abiogenesis

y living things could developspontaneously from non-living materials

y Supported by appearance of living

creatures in decaying meat, stagnatingponds, fermenting grain, and infectedwounds



Experiments to disproveSpontaneous Generation Theory

y Francesco Redi 1668

y did an experiment with flies and wide-mouth jarscontaining meat

y he demonstrated the appearance of maggots in

decomposing meat as a result on the deposition of eggs by flies

y Evidence against spontaneous generation:1. Unsealed maggots on meat 2. Sealed no maggots on meat

3. Gauze few maggots on gauze, none on meat



y

Rudolph Virchow 1858y 1st person to propose the Theory of Biogenesis

Cells can only arise from preexisting cells

y John Tyndally proved that dust carried germs

y also found out that bacterial spores could be killed bysuccessive heating

y tyndallization (Fractional sterilization) - heating withfree-flowing steam for 30-60min for 3 consecutivedays at 100°C



y Anton Van Leeuwenhoek

y

1st

describe bacteria in 1677 with the use of a simple microscope utilizing crude lenses

y 1st person to actually see living microorganisms

y considered as the Father of Bacteriology

y described the 3 major forms of bacteria

(rod,spherical,spiral) fungi, protozoa, spermatozoa



y Robert Hooke 1665

y developed the compound microscope that used reflected light and was able toconfirm Leeuwenhoeks discoveries

y Founded the field of Microscopic Biologythrough his published work -

"Micrographiay first person to coin the word cell to

describe the tiniest components of theliving system



The theory finally changes How do microbes arise?

By 1860, the debate had become so heated that theParis Academy of Sciences offered a prize for anyexperiments that would help resolve this conflict

y Louis Pasteury claimed the prize in 1864,

as he published the resultsof an experiment he did todisprove spontaneousgeneration in microscopicorganisms

y Giving rise to the Theory of Biogenesis



The Theory of Biogenesisyy Hypothesis:Hypothesis: Microbes come from cells of organisms on dust Microbes come from cells of organisms on dust particles in the air; not the air itself particles in the air; not the air itself

y Meat broth was boiled in a flask to kill microorganismsy The neck of the flask was heated and bent into S-shape

y Microorganisms could not get into broth because they would settlein S shaped neck before contact with broth

y No growth was in discovered in the broth

y Broth was tilted into the S component and microorganismscontaminated broth and grew

yy Pasteur·s Pasteur·s SS--shaped flask kept microbes out but let air inshaped flask kept microbes out but let air in..

yy Proved microbes only come from other microbes (life from life)Proved microbes only come from other microbes (life from life) --

biogenesis biogenesis



Germ Theory of Diseasey developed by Louis Pasteury it states that each specific infectious disease is caused by a

specific microorganism

y

Joseph Lister 1860sy used a chemical disinfectant (aqueous phenol) to

prevent surgical wound infections after looking at Pasteurs work showing microbes are in the air, canspoil food, and cause animal diseases

y also developed the first pure culture technique usingliquid medium which was the key to identification of bacteria



y Robert Koch 1876y establish proof of the microbial etiology of 3 important diseases

of this day: y Cholera (Vibrio cholerae)y Tuberculosis (Mycobacterium tuberculosis)y Anthrax (Bacillus anthracis)

y Kochs postulates - which are experimental steps to prove that a specific microbe causes a specific disease

(1) The organism must alwaysbe found in diseased animals

and not in healthy one

(2) Organisms isolated fromthe diseased animals must

be grown in pure cultureaway from the diseased animals

(3) Organisms grown in pure

culture must initiate and reproduce

the disease when re-inoculatedinto susceptible animal

(4) Organisms must bere-isolated from experimentally

infected animals



Exceptions to the Kocks Postulate :

1) Carrier - some individual harbors the organism but do not manifest the disease and can transmit the disease 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 microorganismsome animals are by nature immune

- cannot replicate even with the same specie

some bacterial specie are host specificEx. Vibrio cholerae cannot cause chicken choleraor vice versa



The Golden Age of Microbiologyy 1857-1914

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

y Pasteury Pasteurizationy

Fermentationy Joseph Lister

y Phenol to treat surgical wounds 1st attempt to controlinfections caused by microoganisms

y Robert Kochy Kochs Postulates

y Edward Jennery vaccination

y Paul Erlichy 1st synthetic drug used to treat infectionsy Salvarsan - arsenic based chemical to treat Syphilis



The Birth of Modern Chemotherapy

y 1928: Alexander Fleming discovered the first antibiotic

y He observed that Penicillium fungus made an antibiotic,penicillin, that killed S. aureus

y 1940s: Penicillin was tested clinically and mass produced



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

- Classification- Nomenclature- Identification

Carl Linnaeus

- the Father of Taxonomy- His system for naming, ranking, & classifying

organisms is still in wide use- He established the system of scientific nomenclature:

Genus & specie



Classification

y organization of microorganisms that share similarmorphologic, physiologic and genetic traits into specificgroups or TAXA

y Genus: comprised of different species that have severalimportant features in common but differ sufficientlyto still maintain their status as individual specie

y Species: most basic taxonomic group and may bedefined as a collection of bacterial strains that sharemany common physiologic and genetic features andas a group differ notably from other bacterial specie



Levels of Classification

y Taxon: y A group or level of classification

y Hierarchical; broad divisions are divided up intosmaller divisions:

KingdomPhylum

Class

OrderFamily

Genus

Species



Identification

y process by which a microorganisms key features are delineatedy the profile is compared with those of other previously characterized

microorganisms so that the organism in question can be classifiedwithin the most appropriate taxa and can be assigned an appropriateGenus and Species name

y General categories of identification method:y G enotypic characteristics

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

y Phenotypic characteristics

y includes readily observable characteristics

y Morphology, staining rxn., antigenic properties, environmental &nutritional requirements, resistance profiles



Nomenclature

y naming of microorganisms according to established rulesand guidelines provide the accepted labels by which

organisms are universally recognized

y Scientific name (Systematic Name)

BinomialSystem of Nomenclature

y The first letter of the genus name is always capitalized, but never the first letter of the species name

y A genus name may be used alone to indicate a genus group;a species name is never used alone

y

Genus and species are either underlined or italicizedEschericia coli or Eschericia coli

y The genus may be abbreviated with the first letter, and thespecies is written out

E. coli



y before microorganisms were discovered all living thingswere believed to be either plants and animals

y no transition type were thought to exist

y after discovery of microorganism

it was clear that microorganism combines both plant and animal properties



Haeckel proposed that microorganism be placed inanother kingdom

y Kingdom Protista

y members of this kingdom are distinguished from plants and animals

y Algae

y

Protozoay Fungi

y Molds (multicellular)

y Yeasts (single-celled)

y Kingdom Monera

y Monera is the only "kingdom" containing prokaryotic organisms

y Bacteriay cyanobacteria (blue-green algae)

y archaebacteria



Kingdom Protistaq

members of this kingdom are distinguished fromplants and animals by their following characteristics

1. Simple organization2. Unicellular or Multicellular

Protist- undifferentiated unicellular organisms that do not form thespecialized tissues and organ systems of higher plants and animals

2 Distinct Cell types:1) Eucaryote (Higher Protista)2) Procaryote (Lower Protista)



EU RYOTES hi her r tists

ex: l e (red l e, r l e, reen l e)

f ngir t z

sli e lds



characteristics:- possess a well defined nucleus w/c contain the genetic information of

the cell in multiple strands of DNA and proteins called chromosomes

- nucleolus w/c exist w/in the nucleus and plays a role inthe production of ribosomal RNA and ribosomes

- contain membrane enclosed organelles that have specificcellular functions and site where chemical activities takes place

- cytoskeleton which provides support for the different organelles

- contain complex phospholipids, sphingolipids, histones, sterols- mitochondria are sites of energy production for cellular work- ribosomes (80s) are masses of RNA and proteins that function as the

site for protein synthesis- golgi apparatus is where protein is packed for export - endoplasmic reticulum is involved in the transport of newly synthesized

proteins- lysosomes are vesicles that contain enzymes for cellular digestive

process- cell membrane regulates flow of material in and out of the cytoplasm

method of cell division:

mitosis



PROK ARYOTES

lower protists

bacteria,cyanobacteria (blue-green algae)archaebacteria (methanogens,extreme halophiles,thermoacidophiles)

characteristics:- lack a nucleus or nuclear membrane-has a ribosome (70s)- absent mitochondria- have no organelles, histones and

only in rare cases complex phospholipids, sphingolipids and sterols- chemical activities takes place in the cytoplasm- have a cell wall composed of peptidoglycan with muramic acid- are haploid with a single chromosome composed solely of DNA

method of cell division: binary fission

micro introduction

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