nCU1
-
Science and Microbiology
Microbiology is the study of all living organsims
that are too small to be visible by the naked eye
a.
b.
c.
d.
e.
f.
g.
Bacteria
Archaea
Viruses
Fungi
Prions
Protozoa
Algae
---- all of these are known as MICROBES
--------------------------------role ((nutrient cycling,
biodegrading, climate change, biofuels
manufacturing, pollution cleaning, processing
and producing of food))
MICROORGANISMS
-
Can only be seen under a microscope
Maintain balance of chemical elements
Breaking down remains of dead
Recycling: C, N, S, P, etc.
Some may cause infectious diseases by:
------ great number
------ producing toxins
HISTORY
1. Robert Hooke (mid 1600s_
- Observed strands of fungi among the
specimens of cells he viewed
- Made key observations under the
microscope
2. Anton van Leewenhoek (1670)
- Dutch merchant
- “Father of Microbiology”
- Known for the “animalcules”
- The FIRST to provide an ACCURATE
description of the protozoa, fungi, and
bacteria
3. Frederick Griffith (1928)
Discovered the BACTERIAL
TRANSFORMATION
- Worked with pneuomococci
(pneuomonia causing bacteria)
- Mixing pathogenic fragments of dead
bacteria to harmless ones, would
render the harmless as a pathogenic
- 1st experiment to demonstrate that
bacterias could undergo GENETIC
CHANGES
4. Joshua Lederberg and Edward Tatum
(1940)
- 1st to postulate about the “Bacterial
Conjugation”
2 types of cells
1.
-
Prokaryotic cells
Lacks nucleus
Probably the smallest living organism
---usual sizes
A. 0.15 µm –mycoplasmas
B. 0.25 µm- chlamydiae
C. 0.45 µm- rickettsiae
D. 2.0 µm- many of the basterias
---shapes
A. cocci- spherical
B.bacilli- rodlike
C. vibrio- comma shape
D. spirochete- flexible, wavy shape
E. spirillum- corkscrew
Pleomorphic- ricketssiae and
mycoplasms
- Cling to each other in a distinct
arrangement
- -- ex. Diplococcus (two cocci),
staphylococcus (grapelike/many cluster
of cocci)
2. Eukaryotic Cells
- Larger and more complex than
prokaryotes
- Contains various organelles
(compartments for localizing metabolic
function)
SIMMILARITIES
-
Both has DNA for their genetic
information
Take Note: viruses are neither a prokaryote nor
a eukaryote
-
Not a living organism but can replicate
MICROBIAL METABOLISM
1. Cellular respiration
- producing energy necessary for a
metabolic process to happen by using
O2 and realeasing CO2 and other waste
products
- Either by photosynthesis or not
depending on the microorganism
2. Photosynthesis
- Synthesizing their own food
(autotrophs) by CO2 and water
- Unicellular algae
- Bacteria
- Cyanobacteria
3. Chemical reactions and energy
- Organization is maintained by energy
usage
- Shift of energy/ large loss of energy
- Activation energy- required for
combination or breaking of compunds
- --------using heat energy, chemical
energy, and catalysts to spark an energy
GROWTH REQUIREMENTS FOR
MICROORGANISMS
1. Chemical requirements
- Requires water, mineral elements,
growth factors, gas, oxygen
chemical substances of microorgs has C
- Producing nutrients from simple
INORGANIC COMPOUNDS (CO2)
- Chemoautotrophs- chemical reaction
- Photoautotrophs- photosynthesis
-
Nitrogen- used for proteins, DNA and
RNA synthesis (nitrogen fixing bacteriaRhizobium and Azobacter)
- Phosphorus- nucleic acid synthesis and
phospholipid construction
- Oxygen- for cellular respiration of
AEROBIC BACTERIA
- ---ANAEROBIC BACTERIA- lives in
environment that lacks oxygen
- produces odoriferous gas
- ----MICROAEROPHILLIC- live in low
levels of O2 (capnophillic)
- Trace elements- Au, Cu, Zn
2. Physical Requirements
a. Temperature
- Psychrophile- cold 0 oC- 20
- Mesophile- 20 oC-40 oC
- Thermophile- higher than 40 oC
b. pH of solution
- neutrophilic BACTERIA- in body
- acidophilic- below 6.0 (sauerkraut,
yogurt, orgs: yeast and mold)
c. osmotic pressure
- 1%- normal salt concentration of
microbial cytoplasm
- Halophilic- microorganisms in high salt
concentration (diatoms and
dinoflagellates)
MICROBIAL REPRODUCTION AND GROWTH
1. Cytokinesis (unicellular algae and
protozoa)- asexual splitting of cell
2. Binary fission (bacteria)- DNA duplicates
then divide the cell into two
3. 30 mins-3 hrs.- range of generation
time of reproduction of bacteria
4. Growth curve
a. Lag phase (1st phase)
- Population remains same
- Accustoming to environment
b. Logarithmic phase (2nd phase)
- Optimal level of bacterial growth
- Rapidly doubling
- Represented by a STRAIGHT LINE
-
-
Metabolic peak
c. Stationary phase
Reproduction is offset by DEATH
plateu
Accumulation of waste
Lack of nutrients
Umfavorable environmental conditions
d. Death phase
May enter this stage if unfavorable
environment conditions was not altered
during the stationary phase
Rapid dying
MICROBIAL GENETICS
1. Bacterial conjugation
- Gene transfer occurs when 2 bacteria
come together and mate
- One donor (F+) and recipient (has F-)
- A sex pilus joins the donor and recipient
(during transfer)
- F factor plasmid- DNA most often
transferred
- --- produces DOUBLE-STRANDED DNA
FOR INTEGRATION
- Special conjugation tube- channel for
transferring
- F factor- episome
- integrates itself to the
chromosome
- High Frequency recombination (Hfr)
donor- the donor
- F factor is rarely transmitted,
recipient cell cannot become donor cell
- Take Note: if F factor is transferred
during conjugation, the donor cell can
be a recipient cell
- F plasmid- carries an excised
chromosomal DNA
- Sexduction- happens when the F
plasmid is transferred to a recipient
during conjugation then the donor
genes are also transferred
2. Bacterial Transformation
- Competent cell- in a log phase and
needs a COMPETENCE FACTOR for
transformation
- takes up DNA and destroy one
strand the double helix
- Replacing as a similar but not
identical strand
- complete transformation
- Streptococcus pneuomoniae and
Haemophillus influenza- used for study
of transformation
3. Bacterial Transduction
- 3rd important kind of BACTERIAL
RECOMBINATION
a. Lytic Cycle
- Bacteriophages (BACTERIAL VIRUS)
transfer DNA from one bacterium donor
to another recipient bacterium
- encourages the bacterium to make a
copy of it
- host bacterium LYSE and release
new phages
b. Lysogenic cycle
- viruses may integrate its DNA to the
bacterial DNA
- does not lyse the bacterium (temperate
phase/PROPHAGE)
- virus detach at a later time and the
lytic cycle will now proceed to happen
4. Mutation
- Permanent alteration in sequene of the
nitrogenous bases (A, T, C, and G) of
DNA
- Beneficial/detrimental
TYPES
a. Point mutation- most common
- Single base pair
- Substituting a different base to a
normal base
b. Missense mutation
-
-
-
-
Substitution of new amino acid in the
FINAL PROTIEN
c. Nonsense mutation
Changing of genetic code and
destroying of information
d. Frameshift mutation
Adding/Deletion of pairs of nucleotides
in the DNA
The READING FRAME is shifted
Spontaneous mutation- NOT in
laboratory
Induced mutation- in laboratory
MUTAGENS
Agents capable of bringing mutations
a. Chemical mutagens
Nitrous acid- converts adenine to
HYPOXANTHINE (can’t pair with
thymine)
Base analog- incorporated by error in
DNA
Resembles a nitrogenous base
Dyes & fungal toxins (aflatoxin)
b. Physical Mutagens
X ray, gamma ray, UV light,
X ray & gamma ray- Breaks covalent
bonds of DNA molecule
UV light- binds together adjacent
thymine bases, forming DIMERS
Photoreactivation- bacterial enzymes
that can repair radiation damage
Mutation rate- probability of a mutation
occurring in a cellular division
Bacteria 1/1 bill
MICROBIAL SYSTEM OF CLASSIFICATION
-
taxonomy- science of classification
taxon- alternative expression for a
classification category
Carolus Linnaeus (1750-1760)- 1st
taxonomists and classified all known
plants and animals during his time
CLASSIFICATION SCHEME
1. Species- fundamental rank
- Population that breed among
themselves
- 70% similarity in biochemical
2. Genus –
- group of various species (Shigella
flexneri & Shigella boydii)
- Atleast 70% similar
3. Family- various genera
- Grouped because of simmilarites
4. Order
- Various family
5. Class
- Grouped order
6. Phylum/division
- Where group of class is categorized to
7. Kingdom
- Broadest classification entry
CRITERA FOR ESTABLISHING SPECIES
a.
b.
c.
d.
e.
Morphology
Cellular features
Biochemical properties
Genetic characteristics
Antibodies
5 KINGDOMS
- Classified by Robert Whittaker (1969)
1. Monera- prokaryotes like protozoa and
cyanobacteria
2. Protista – eukaryotes and single celled
protozoa, unicellular algae, and slime
molds
3. Fungi- eukaryotes that bacterial
enzymes absorb simple nutrients from
soil like molds mushrooms, and yeast
4. Plantae- plants
5. Animalia- animals