Microbiology
study of microorganisms
Microorganisms Include
bacteria, protest, some algae and some fungi
Cell
fundamental unit of all living matter
Features of Living Cells
1- Self Feeding
2- Self replication or growth
3- Differentiation
4-Chemical signaling/ communication
5- Evolution
We look at cells by?
1. Chemical Machines
2. Coding devices
Kinds of Cells?
Prokaryote and Eukaryote
Prokaryote
before nucleus
Eukaryote
true nucleus
Prokaryote Cell Features
cytoplasmic membrane, cell wall and cytoplasm
Nucleoid
in prokaryote cell, meaning before bacterial chromosome
What do prokaryotes include?
archaea and bacteria
what do eukaryotes include
some microorganism, like yeast and algae
Viruses
not cells
each varies particle in unchanging
must have another organism to grow and replicate
has genetic info.-- this lacks machinery to grow and replicate
bag of protein containing nucleic acid (either DNA or RNA, never both)
Identification
binomial system by Linneaus
K P C O F G S
kingdom, phylum, class, order, family, genus, species
Bacteria
typical prokaryotes seen in microbiology lab
Archaea
1. like extreme environments (extremophiles)
2. May represent early forms of life
Microbes affects us by?
1- cause disease
2- Argiculture
3- Food Industry
4- Microbes and Energy
5- Microbes in the future
Cause disease
microbes
Agriculture
1- nitrogen fixation
2- Digestion in ruminates, like cows, horses, sheep
Food Industry
1- food spoliage
2- food production
3- food ingredient production
Microbes & Energy
1- methane production
2- petroleum processing
3- alternative energy sources
Biotechnology --Microbes in the Future
use of microbes in lg. scale industrial processes
Biohydrometallurgy --Microbes in the Future
use of microbes to extract metals and ores
Bioremediation --Microbes in the Future
use of microbes to clean up environment
Biosensors --Microbes in the Future
living microbes, enzymes, or organelles linked to electrodes to covert biological reactions into electrical currents
History of Microbiology
linked to discovery of microscope
Lucretius
98-55 BC
thought disease caused by invisible particles
Robert Hooke
1664
first to describe fruiting bodies of mold
Antoni van Leewenhoek
1676
first to correctly describe bacteria and protozonans
Franceso Redi
1668
disproves sponanteous generation in higher animals
Louis Pasteur
1861
disproved theory of spontaneous generation for all organisms
Tundall & Chrom
1867/1877
boiling not sufficient for sterilization (discovered bacterial endospores)
Robert koch
1884
germ theory of disease
Koch's Postulates
1. Orgaisms only present in sick animals: not healthy animals
2. Cultivate in pure cultures away from animal body
3. Culture should cause diseases when placed in susceptible animals
4. Isolate &culture organism from animals (3), same organisms as (1)
Fannie Hesse
1882
had the idea of using agar to culture bacteria
Julius R. petri
1887
developed Petri dishes
Microbiology Today
Divided into 2 aspects
1. applied
2. basic
cell membrane
-distinguished outside from inside
-selective permeability bilayer
-composed of a phospholipid bilayer
-contains proteins
integral or intrinsic proteins
transmembrane, tightly associated
Peripheral or Extrinsic Proteins
loosely associated, easily removed by salt and nonionic detergents
membrane-associated proteins
tightly associated yet dont space the membrane, like lipoproteins)
Membranes also contain
-Ca and Mg ions
-hopanoids
Ca and Mg ions
stabilize membrane by combining with negative charges of phospholipids
Hopanoids
functions to strengthen membrane
(like rebar in cement)
Bacteria
1.Ester linkage (H-C-O-C=OR), between fatty acids and glycerol
2.No Sterols in the F.A
Archaea
Ester Linkage (OC-O-C-R)
isoprene instead of F.A
Eukaroytes
Ester linkage
contains sterols in F.A
fluid mosaic model
membranes are fluid
phospholipids and proteins can move 2-dimensionally but cant flip-flop
Membrans are selective permeability barrier
-fat soluble compounds
-charged particles
-water can easily across
Fat Soluble Compounds
may become membrane associated and enter the cell
Charged particles
(H+) cant enter, requires transport systems
Water can easily cross
membranes by osmosis
Hypotonic environment
water enters cells causing is to swell and burst
Hypertonic environment
water slows outside the cell causing it to shrink, which is plasmolysis
Transport Systems
involves transport proteins (integral)
uniporters
one substance in one direction only
cotransport proteins
move one substance along with a 2nd, required for transport of the first
---symporters
---antiporters
Synporters
both substances in the same direction
Antiporters
substances go in opposite directions
facilitated diffusion
- no energy involved
-transport protein directs substances by conformational charge
Active Transport
- requires energy to pump against concentration gradient
-transported substance is NOT altered
- energy comes from ATP hydrolysis
-also energy can come from pumping H+ or Na+ ions outside the cell
----this promotes proton motive forces
Negative Charges -Active Transport
charged/neutral nutrients pumped in with protons
Positive Charges- Active Transport
charged nutrients enter alone
group translocation
-requires energy
- substance is transported and at the same time chemically modified, by phosphorylation
-no actual gradient formed bc substances is NOT the same in and out
phosphotransferase system
-example of group translocation
-glucose, fructose, mannose, n-aceltyglucoasmine and beta-glycosides are phosphalted during transport
-this regulated sugar transport since glucose preferentially phosphorylated
Cell Wall
-gives bacteria their shape
-provides rigidity and strength
-composed of peptidoglycan
---->polymers o glycan tetrapetide monomer
Coccus
circle
Rod
long circular shape
Spirilllum
long and flowly
Spirochete
circle disk stacked on top of each other
filamentous
looks like hair
Monomer Structure of peptidoglycan
2sugars(N-acetylglucosamine&N-acetylmuramicacid)linkedtogetherbyb1-4linkage
� lysozyme attacks this bondo attachedtoN-acetylmuramicacidare4aminoacidslinkedbypeptidebonds
� amino acids: L-ala, D-ala, D-glu, & either lys or diaminopimelic acid (DAP).
6
o st
Unique features of Peptidoglycan
-muramic acid
-DAP
-D- forms of A.A are used
Gram Positive Cell Wall
-thick cell wall
-reain crystal violet (purple) dye
Gram Negative Cell Wall
-think cell wall
-cyrstal violet is washed out and stained red/pink with safranin dye
LPS
lopoplysaccharide--effective 2nd lipid bilayer
Core Polysaccharide
composed of ketodeoxyoctonate, several kind of sugars
O polysaccharide
hexoses and unusal dideoxy suagrs
-linked to core polysaccharide
Lipid A
lipid portion
linked to polysaccharide by ester amine linkage
Gram Neg Cells
outer memebrane
periplasm
inner/cytoplasmic/ plasma membrane
Gram Positive Cells
-no lps, smaller periplasm
-do have techie acids attached to outer surface of cell wall
Cell Wall Synthesis
-peptidoglycan produced in cytoplasm
-Autolysin
-Transpeptidation
Autolysin
-makes small openings in the cell wall & new cell wall material is added
-autolysisn may occur if the above is not carefully coordinated
Transpeptidation
-links one chain to another by peptide bonds
-inhibited by penicillin