Transcript INTRODUCTION TO MICROBIOLOGY

Assistant Professor Microbiology
Syed Yousaf Kazmi
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Explain the fundamentals of Microbiology
Describe the basic characteristics of bacteria,
viruses, fungi and parasites
Describe microorganisms of medical imp
Recall the contributions of Robert Koch and
Loius Pasteur
Tragedy of EyamMompesson’s well 1665-66
 Plague hit England
 Villagers decided to stay
 260 died of 350 residents
 Famous rhyme recalls
A ring-a-ring of rosies
A pocketful of posies
A tishoo! A tishoo!
We all fall down
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In 1665, Robert Hook observed
various objects with lenses of
25x magnification
Used term Cella
In 1674, Antony Van
Leeuwenhoek cloth merchant
in Holland
First simple microscope
magnification of 200X
Coined term Animacules for
bacteria from mouth
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Mid 17th century-disease
occurred due to altered
chemical quality atmosphere
Mola Aria ( Bad Air) Now is
Malaria
In 1854 Cholera Epidemic in
London Soho district
John Snow map plotting of
cholera cases
Clustering of cases near
Broad Street pump
Cholera-waterborne not
miasma related
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Louis Pasteur French Chemist
observed yeasts in sour wines
Heated the wine at 56oC to kill
yeasts( Pasteurization)
Germ theory of disease
In 1865 cholera hit Paris
Filtered water to capture
pathogen
Anthrax bacillus filterabledeposit did not cause disease
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Rejected Spontaneous
Generation theory once
and for all
Swan neck flask is still
present in France Museum
In 1884, Pasteur developed
weak strain of chicken
cholera-Vaccine
Same experiment Anthrax
In 1885, successfully
immunize young boy
against rabies
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Robert Koch German doctor
1875 Koch injected blood
from Anthrax diseased sheep
into mice-same symptoms
Autopsies- same findings
Isolated rod shaped cell-grew
in ox eye
Microscopy-multiplication
till spores
Injected spores into healthy
mice-anthrax
Autopsied mice- observed
same bacilli
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In 1882, Robert Koch
isolated bacterium
responsible for TB
In 1883, he isolated
curved shaped bacillus
from cholera victims in
Egypt and India
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350 b large galaxies & > 1022 stars in visible
universe
Microbial universe- 1031 microorganisms
Microbes present everywhere
Antartica, Mount Everest, Deep oceans, miles
down crust of earth
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Microbes are living things
with usually singe cell
Viruses are non cellular
Parasites (Helminths ) are
multi-cellular
Involved in cycling of N, C,
S, P etc
Photosynthesis, 50%of O2
Approx 90% of cells in
human are microorganisms
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Only small %-Pathogen
Pathogen- Microorganisms
with ability to cause disease
Bacteria, Viruses, Fungus,
Parasites etc
Bacteria, Fungi & Parasites
have necessary enzymes and
equipments for replication
and metabolism
Viruses depends upon host
cell for function
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Very Minute- Need
electron microscope
Acellular
No nucleus
Either DNA or RNA
Replicates in host cells only
No ribosome
No functional cell
membrane
No cell wall
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Small- Need simple
microscope
Prokaryotic
No specific nucleus
One chromosome only
DNA and RNA
No membrane bound
organelle
70S ribosome
Replicate by binary fission
Cell membrane without sterol
except
Cell wall composed of
Peptidoglycans
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Small
Eukaryote
Proper nucleus, nuclear
memb
More than 1 chromosome
Mitochondria & other cell
bound organelle
80S ribosome
Cell membrane Ergosterol
Complex carbohydrate cell
wall –Chitin, Mannan,
Glucans
Aspergillus flavus
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Small but helminth are macroscopic
Eukaryote like fungi except
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Cell membrane has cholesterol
There is no cell wall
Giardia lamblia
Features
Viruses
Bacteria
Fungi
Parasites
Size
0.02-0.3 µ
0.3-2µ
3-10µ
15-25µ#
Cell Type
Acellular
Prokaryote
Eukaryote
Eukaryote
DNA/ RNA
Either
Both
Both
Both
Nucleic acid
replication
Host cell
Continuous
G & S phase
G & S phase
Replication
Complex
Binary fission
Mitosis/
Meiosis
Mitosis/
Meiosis
Organelle
Uses host
Not membrane
bound
Membrane
bound
Membrane
bound
Ribosomes
None
70S(30S+50S)
80S(40S+60S)
80S(40S+60S)
Cell memb
Env/Non
env
No sterol
#Mycoplasma
Ergosterol
Cholesterol
Cell wall
None
Peptidoglycan
Chitin,
Glucan
None
A scientist is studying a cell that has
mitochondria in its cytoplasm. Which of the
following structure will not be present in this
cell?
1. Nuclear membrane
2. Ribosome
3. Cell membrane
4. Cell wall containing peptidoglycan