1. Introductory Microbiology
Dr. Heather Townsend

2. Characteristics of Life
Growth and development
Reproduction and heredity
Metabolism
Movement and/or irritability
Cell support, protection, and storage mechanisms
Transport of nutrients and waste
Living things are made of cells!!

3. All cells……. Have an outer plasma membrane Contain DNA
Enclosed within the cell somewhere
Contain cytoplasm
Everything between the plasma membrane and the region of DNA
Gives cells their shape
Assist in movement of cell and organelles

4. Characteristics of Microbes
Prokaryotic cells
Smaller
Lack special structures such as a nucleus and organelles
All prokaryotic cells are microorganisms
Some microorganisms are eukaryotic
Viruses?

5. “Micro”organisms

6. Characteristics of Cells
Eukaryotic cells
Animals, plants, fungi, and protists
contain double-membrane bound nucleus with DNA
contain membrane-bound organelles
10–100 µm in diameter

8. Characteristics of Cells
Prokaryotic cells
~1.0 µm in diameter
Bacteria and archaea
no nucleus
no membrane-bound organelles

12. Microbiology
The study of of organisms (microorganisms or microbes) too small to be seen without magnification
This includes:
Bacteria
Viruses
Fungi
Protozoa
Helminths (worms)
Algae

13. Klebsiella pneumoniae, bacteria that causes pneumonia in humans
The Microbes
1. Bacteria
Single-celled organisms
Various shapes
Spherical
Rod
Spiral shapes
Cellular
Lack membrane-enclosed cellular structures
Widely distributed in nature
Klebsiella pneumoniae, bacteria that causes pneumonia in humans

14. The Microbes 2. Viruses Acellular
Composed of nucleic acid and a few proteins
Replicate themselves to display other properties of living organisms when they invade living cells

15. The Microbes 3. Fungi Yeasts and molds Mushrooms
Single-celled, microscopic
Mushrooms
Multicellular, macroscopic
Cell nucleus and other cellular structures
Absorb nutrients from their environment
Widely distributed in water and soil
Act as decomposers of dead organisms
The Microbes

16. The Microbes 4. Protozoa Single-celled, microscopic organisms
Have at least one nucleus and many cellular structures
Obtain food by engulfing or ingesting smaller organisms
Most can move
Found in many different environments
The Microbes
Amoeba

17. The Microbes 5. Helminths Large, multicellular Parasitize host tissues
Organs for reproduction, digestion, movement, protection
Mouthparts
Ingestion of larvae or eggs in food
Tapeworm Head

18. Micrasterias, a green algae living in
The Microbes
6. Algae
Single-celled microscopic organisms
Have a nucleus and many membrane-enclosed cellular structures
Photosynthesize their own food
Widely distributed in fresh and salt water
Important source of food for other organisms
Micrasterias, a green algae living in
fresh water

19. General cell characteristics
Locomotor appendages
External boundaries

20. External Structures of Cells
Locomotor appendages
flagella
long, sheathed cylinder containing microtubules
covered by an extension of the cell membrane
function in motility
cilia
similar in overall structure to flagella
shorter and more numerous
found only on a single group of protozoa and certain animal cells
function in motility, feeding and filtering

21. External Boundary Structures
Plasma (cell) membrane
typical bilayer of phospholipids and proteins
serves as selectively permeable barrier in transport

22. External Structures of Cells
Glycocalyx
an outermost boundary that comes into direct contact with environment
usually composed of polysaccharides
appears as a network of fibers, a slime layer or a capsule
functions in adherence, protection, and signal reception
Beneath the glycocalyx:
Fungi and most algae - cell wall
Protozoa, a few algae, and all animal cells – cell membrane

23. External Boundary Structures
Cell wall
Fungi
thick inner layer of polysaccharide fibers
composed of chitin or cellulose and a thin layer of mixed glycans
Algae
varies in chemical composition
substances include cellulose, pectin, mannans, silicon dioxide, and calcium carbonate
Bacteria!!!
Dependent on cell wall composition

24. Prokaryote
Eukaryote

25. Branches of Study Within Microbiology
Immunology:
studies immune chemicals and cells that are produced in response to infection
Public health microbiology & epidemiology:
aim to monitor and control the spread of diseases (CDC)
Food, dairy and aquatic microbiology:
examine the ecological and practical roles of microbes in food and water
Biotechnology:
ranges from bread making to gene therapy
Genetic engineering & recombinant DNA technology:
altering the genetic makeup of organisms

26. Microbes Are Involved In:
nutrient production & energy flow
i.e., photosynthesis
decomposition and nutrient recycling
production of foods, drugs & vaccines
bioremediation
causing disease

27. Impact of Pathogens Pathogens
Diseases-causing agents
Nearly 2,000 different microbes cause diseases in the human body
10 B infections/year worldwide
13 M deaths from infections/year worldwide
killing about 1/3 of the U.S. population each year

28. Impact of Pathogens Emerging diseases Reemerging
Becoming more prominent over the years
Zoonosis
SARS
Reemerging
Older diseases increasing in occurrence TB
Malaria
Hepatitis

29. Historical Microbiology
1546 – physician suggest that invisible organisms may be involved with disease
Abiogenesis vs biogenesis

30. Antonie van Leeuwenhoek
First to observe living microbes
His single-lens magnified up to 300X
( )

31. Early Medical Microbiology
Spontaneous generation
“Living things arise from nonliving things”
Belief that some forms of life could arise from vital forces present in nonliving or decomposing matter
Debate over spontaneous generation led in part to development of scientific method

32. Early Medical Microbiology
Louis Pasteur:
Worked in the wine industry
Had knowledge about yeast producing alcohol
Swan-neck flasks
Tipping the flask would allow the microbes to enter the infusion
Cause them to become cloudy
Main experiment that helped disprove spontaneous generation
Developed Pasteurization
Developed a rabies vaccine

33. Early Medical Microbiology
Robert Koch (~120 years ago, German)
Linked a microscopic organism with a specific disease (anthrax)
Developed method to grow bacteria in pure cultures (cultures containing only one kind of organism)
Used solidified gelatin from potato slices mixed with agar
Creates a firm surface that microbes could grow on

34. Koch’s Postulates
The specific causative agent must be found in every case of the disease
The disease organism must be isolated in pure culture
Inoculation of a sample of the culture into a healthy, susceptible animal must produce the same disease
The disease must be recovered from the inoculated animal

36. Early Medical Microbiology
Oliver Wendell (American physician)
observed mothers who gave birth at home experienced fewer infections than those that gave birth in a hospital
Ignaz Semmelweis (Hungarian doctor)
showed that women became infected with puerperal fever during delivery by doctors coming directly from the autopsy room

37. Early Medical Microbiology
Joseph Lister (English surgeon)
Introduced aseptic techniques
Aimed at reducing microbes in a medial setting and preventing wound infections
Improved sanitation
Promotes use of carbolic acid on bandages and medical instruments

38. 1900s Alexander Fleming Two types of cells recognized!!!
observed that a species of Penicillium mold killed bacterial cells
led to the development of penicillin
Two types of cells recognized!!!

39. Microbiology—Now Microbiology continues to face many challenges
A pathogen can cause more than one disease
Pathogens are becoming resistant to antimicrobials
Pathogens can be used intentionally to infect large numbers of people through bioterrorism

40. Science Scientific method
1. Observe some aspect of the natural world and ask questions about it
2. Hypothesis
3. Make predictions
4. Test the predictions
5. Repeat the tests or develop new ones
6. Analyze and report the test results and conclusions

41. Microscopy Micrometer Size Range
Most bacterial and archaeal cells are 1-5 micrometers (µm) in length

43. How to view microbes? Light Microscopy
Visible light passes through multiple lenses and through the specimen
Light microscopes usually have at least 3 lenses
low-power
high-power
oil-immersion

44. How to view microbes? Staining techniques simple stain technique
negative stain technique
Special stains

45. Taxonomy Organizing, classifying and naming living things
In the mid-1700s, Carolus Linnaeus published Systema Naturae, establishing a uniform system for naming organisms
Nomenclature gives scientific names to organisms
Identifying and classifying organisms according to specific criteria

46. Taxonomy
Domain
Kingdom
Phylum
Class
Order
Family
Genus
species

47. 3 Domains Eubacteria Archaea Eukarya true bacteria peptidoglycan
odd bacteria that live in extreme environments
high salt, heat, etc. (usually called extremophiles)
Eukarya
have a nucleus & organelles
Protista
Algae
Fungi
Plantae
Animalia

48. Naming “Most” Micoorganisms
Binomial (scientific) nomenclature
Gives each microbe 2 names:
Genus - noun, always capitalized
species - adjective, lowercase
Both italicized or underlined****
Staphylococcus aureus (S. aureus)
Bacillus subtilis (B. subtilis)
Escherichia coli (E. coli)

49. What to expect…….. Different microorganisms
How to detect microorganisms
Common disease caused by microorganisms
How to control the spread of microorganisms
Immune system