4. Chemical antimicrobial agents used to control
microorganisms that are harmful to humans:
Sterilants destroy all forms of microbial life
; Disinfectants kill microorganisms, but endospores
are typically resistant
Sanitizers reduce the microbial load but may
not eliminate all microorganisms
Antiseptics kill or inhibit growth of
& Germicides microorganisms on living tissue
5. 1888-1955 Alexander Fleming
1929 discovered antimicrobial effects of
penicillin G made by the fungus Penicillium
on Staphylococcus by chance
1945 Nobel Prize in Medicine -
Fleming, Howard Walter Florey and
Ernst Boris Chain
6. Vancomycin
• Glycopeptide antibiotic
• Binds to pentapeptide of the
peptidoglycan precursor
• Produced by a soil microbe
Amycolatopsis orientalis
• Effective against Gram-
positive Bacteria
10. Bacterial cell with
chromosomal mutation Bacterial cell not
altering target of antibiotic resistant to antibiotic
resistant to antibiotic
Transformation
Transfer of free DNA
Lysis of cell
Previously
susceptible cell
is now resistant
to antibiotic
11. Bacterial cell with R plasmid Bacterial cell not
resistant to antibiotic resistant to antibiotic
Chromosomal DNA Conjugation
Copy and Transfer of R plasmid
Previously
susceptible cell
is now resistant
to antibiotic
13. Eon Billion Evolutionary Oxygen Metabolic and
Fig. 14.7 years ago event level other highlights
Comparable to
0 Extinction of the dinosaurs
Fig. 11.8 in the
Phanaerozoic Cambrian
11th edition
0.5 Early animals
Multicellular 20%
1.0 eukaryotes
Precambrian
10%
Proterozoic
1.5
First eukaryotes 1% Ozone shield
2.0
Great oxidation 0.1%
2.5 event
Cyanobacteria Oxygenic photosynthesis
3.0 (2H2O O2 + 4H)
Archaean
Purple and green Anoxygenic photosynthesis
3.5 bacteria (H2S S0 + 2H)
Anoxic
First cellular Methanogenesis
4.0 life (CO2 + 4H2 CH4 + 2H2O)
Hadean Formation of
crust and ocean
4.5 Formation of Earth
14. Fig. 11-9 in the
11th edition
(oxygenic)
(aerobic)
15. The Hydrogen Hypothesis – how the
first eukaryotic was formed?
Host cell -
Archaea
Symbiont cell -
dependent on
Bacteria
H2 for electron
producing H2;
source to make
lipid gene transfer;
energy
precursor of
Symbiont cell –
mitochondrion
photosynthetic
cyanobacterial-
like ancestor
18. Branches show order of descent and node ancestry.
Branch length reprepresents number of nucleotide changes
Fig. 14.14d
Internal nodes
denote common
ancestor
Nodes at the tips
denote species/strains