1. Microbiology – a revisit
study of organisms too small to be seen by the naked eye.
Microbes or Microorganisms
include bacteria, viruses, fungi, algae, protozoa etc.
Prions (“infectious proteins”) are recent addition.

2. Specializations in Microbiology
Epidemiology and Public Health Microbiology
distribution and spread of diseases and their control and prevention
Food Microbiology
use of microbes in the production of food products and drinks
Agricultural and Veterinary Microbiology
use of microbes to increase crop and livestock yield and control of plant pests and animal diseases
Environmental Microbiology
study of the beneficial and harmful effects of microbes on the environment

3. Beneficial Uses of Microbes
Synthesis of drugs, hormones and enzymes

4. Beneficial Uses of Microbes
Bioremediation is the use of microbes to degrade organic
matter in sewage and detoxify pollutants such as oil spills.

5. Modern Uses of Microbes
Biotechnology, the use of microbes as miniature biochemical factories to produce food, drugs, energy..etc
Genetic engineering makes use of molecular biology and recombinant DNA techniques as new tools for biotechnology.
Gene therapy replaces missing or defective genes in human cells through genetic engineering.
Genetically modified bacteria are used to protect crops from pests and freezing.

6. Woese-Fox 3 Domain System
Microbial Taxonomy
Woese-Fox 3 Domain System

7. General Characteristics
Prokaryotes no nucleus and organelles
Eukaryotes membrane bound nucleus and organelles

8. Scientific Names Staphylococcus aureus
describes clustered arrangement of cells and golden yellow color of colonies
Escherichia coli
Honors the discoverer, Theodor Escherich and describes its habitat, the colon.
After the first use, scientific names may be abbreviated with the first letter of the genus and full species epithet. (Ex: E. coli)

9. Comparative cellular structures of microbes
Cell Types
Comparative cellular structures of microbes

10. The Microbes viruses protozoa bacteria bacteriophage algae
cyanobacteria
spirochaetes
fungi

11. Size of Microbes
Microbes vary in size ranging from 10 nm (nanometers) to 100 mu (micrometers) to the macroscopic.
Viruses in nm = m (meter)
Bacteria in um = 10-6 m
Helminths in mm = 10-3 m

12. Bacteria
Prokaryotes
Peptidoglycan cell walls
Ex: Escherichia coli

13. Archaea Prokaryotes Lack peptidoglycan
Live in extreme environments (extremophiles)
Include:
Methanogens
Extreme halophiles
Extreme thermophiles

14. Fungi Eukaryotes Chitin cell walls
Molds and mushrooms are multicellular
Yeasts are unicellular

15. Protozoa Eukaryotes Mostly saprobes and commensals
May be motile by means of pseudopod, cilia or flagella

16. Algae Eukaryotes Cellulose cell walls Photosynthetic
Produce molecular oxygen and organic compounds
Part of food chain

17. Helminths Eukaryotes Multicellular animals
Parasitic flatworms and roundworms called helminths
Microscopic stages in life cycles

18. Viruses Acellular Genome consist of DNA or RNA called Core
Core surrounded by protein coat called Capsid
Virion may be enclosed in lipid envelope

19. Prions Proteinaceous infectious agents
Causes Bovine Spongiform Encephalopathy (BSE)
Also causes Creutzfeldt-Jacob Disease (CJD)
An Emerging Infectious Disease (EID)

20. Microbial Diversity
Microbial diversity encompasses the spectrum of variability among all types of microorganisms in the natural world and as altered by human intervention.
Microorganisms are essential for the earth to function.
They play many roles both on land and in water, including being the first to colonize and improved effects of naturally occurring and man-made disturbed environments.

21. Microbial Diversity
Because microorganisms are small, they are least known, and this gap in knowledge is particularly apparent for bacteria and other procaryotic organisms.
Current evidence suggests there exists perhaps 300,000 to 1 million species of procaryotes on earth yet only 3,100 bacteria are described in Bergey's Manual.
Learning more about these microorganisms will be of value for the following reasons:

22. Microbial Diversity
Microorganisms are important sources of knowledge about the strategies and limits of life,
Microorganisms are of critical importance to the sustainability of life on our planet,
The untapped diversity of microorganisms is a resource for new genes and organisms of value to biotechnology,
Diversity patterns of microorganisms can be used for monitoring and predicting environmental change,
Microorganisms play a role in conservation and restoration biology of higher organisms, and
Microbial communities are excellent models for understanding biological interactions and evolutionary history.

23. Microbial Diversity Factors governing microbial diversity
Abiotic factors – ??
Biotic factors – ??