Introduction to Microbiology

From LUCA, 3 cell types resulted:

1. eukaryotes
2. prokaryotes
3. archaea

microbiology

the study of the life of organisms that cannot be seen with the naked eye and require a microscope to be visualized

characteristics of bacteria (prokaryotes)

1. typically unicellular organisms
2. peptidoglycan cell wall
3. can be different shapes and sizes
4. heterotrophic or autotrophic

bacillus

rod shaped bacteria

coccus

spherical shape

spirilla

spiral shape

vibrio

curved shape

shape of DNA in bacteria

circular

reproductive strategy of bacteria

binary fission (asexual reproduction)

cell type of bacteria

1. gram positive
2. gram negative

environments for bacteria

1. aerobic
2. anaerobic
3. halophilic
4. acidophilic

characteristics of archaea (prokaryotes)

1. lacks nucleus
2. pseudomurein cell wall (lacks peptidoglycans)
3. unicellular
4. microscopic

shape of DNA in archaea

circular

halophiles

archaeans that live in salty environments

thermophiles

archaeans that live at extremely hot temperatures

psychrophiles

archaeans that live at cold temperatures

methanogens

methane-producing organisms

characteristics of fungi (eukaryotes)

1. possess a nucleus
2. chitin cell wall
3. heterotrophic
4. can be unicellular or multicellular

shape of DNA in fungi

linear

reproductive strategy of fungi

1. asexual reproduction
2. sexual reproduction

saprophytic fungi

live on organic matter

parasitic fungi

live on or within other living organisms

types of parasites

1. helminths
2. protozoa

characteristics of protozoans

1. eukaryotic
2. mostly heterotrophic
3. mostly unicellular
4. mostly lack a cell wall
5. larger than bacteria 3 - 2000 μm
6. mostly motile

environments for protozoans

1. aquatic environment
2. terrestial environments

helminths

parasitic worms

* burrow into the human host and cause disease

characteristics of helminths

1. no cell wall
2. heterotrophic
3. contain microscopic stages

reproductive strategy of helminths

1. asexual reproduction
2. sexual reproduction

trematodes

flatworms

nematodes

roundworms

cestodes

tapeworms

characteristics of algae

1. eukaryotic
2. cellulose cell wall
3. unicellular or multicellular
4. often contain pigments (red, green, brown)
5. autotrophic (photosynthetic)

reproductive strategy of algae

1. asexual reproduction
2. sexual reproduction

characteristics of viruses

1. acellular
2. microscopic
3. may be naked or enveloped
4. contains protein coat (capsid)
5. may be DNA or RNA

pathogen

microbe that causes diseases

infectious disease

disease caused by a pathogen

* Pathogen colonizes the body.

microbial intoxication

disease caused by ingesting a toxin produced by a pathogen in vitro

example of infectious disease

Myobacterium tuberculosis (TB)

example of microbial intoxication

Staphylococcus aureus (food poisoning)

saprophytes (decomposers)

lives on dead or decaying organic matter

bioremediation

use of microbes to recycle wastes or clean contaminated areas

What is the role of microbes?

1. recycle organic material
2. play a role in nitrogen cycle

What is the role of plankton?

1. food chain
2. oxygen production

phytoplankton

smal marine plants and algae

zooplankton

small marine animals

uses of microorganisms in industry and biotechnology

1. food production (cheese, alcohol, bread)
2. genetic engineering
3. mining
4. pharmaceutical industry
5. biofuels

bacteriology

study of bacteria

mycology

study of fungi (moulds, yeast)

parasitology

study of parasites

phycology/algology

study of algae, seaweeds

immunology

study of the immune systemm

morphology

study of form and structure

physiology

study of metabolism

taxonomy

study of classification

ecology

study of the interactions between living organisms and their environment (distribution, relationships)

requirements for identification of a species

1. physical characteristics
2. growth and energy requirements
3. metabolic processes carried out

Who proposed binomial nomenclature in 1735?

Carolus Linnaeus

binomial nomenclature

1. Latinized naming system
* Genus = capitalized
* Species = lowercase
* BOTH = *italicized* or __underlined__ __separately__

classification of the 3 domains of life

1. bacteria
2. archaea
3. eukarya

Classification is based on what?

16S ribosomal RNA

* The more the rRNA is similar, the closer the organisms are related.

classification of a species

1. kingdom
2. phylum
3. class
4. order
5. family
6. genus
7. species

When was the “golden age of microbiology”? (first age)

* What happened during this period?

1657-1914

* spontaneous generation theory
* germ theory of disease
* disease prevenion

Antoni von Leeuwenhoek

1. built a microscope
2. observed living microorganisms
3. provided accurate images, drawing, and descriptions of fungi and bacteria

Who were responsible for the spontaneous generation theory?

1. Franscesco Redi
2. John Needham
3. Lazzaro Spallazani

Louis Pasteur

1. questioned why wine soured
2. developed pasteurization (gentle heating of the liquid killed the bacteria but did not spoil the wine or allow it to evaporate)

Who were responsible for the Germ Theory of Disease?

1. Ignaz Semmelweis
2. John Snow
3. Joseph Lister

Ignaz Semmelweis

1. correlated infections of mothers to physicians who had not washed their hands after visiting autopsy rooms
2. implemented handwashing practices in birthing wards

John Snow

1. contradicted miasma theory
2. conducted first scientific studies of the effects of anesthetics

Joseph Lister

1. introduced aseptic techniques to reduce microbes in medical settings
2. disinfection of hands with carbolic acid
3. cleaned equipment between surgeries
4. use of heat sterilization

Robert Koch

1. isolated Bacillus anthracis (causative agent of anthrax)
2. established Koch’s Postulates

Koch’s Postulates

1. The suspected causative organism should always be present along with the specific disease and absent in healthy animals.
2. The suspected organism can be grown in pure culture.
3. Organisms taken from the pure culture should cause disease in a healthy animal.
4. The organism can be re-isolated and shown to be the same as the original.

problems/exceptions to Koch’s Postulates

1. Some organisms are difficult/impossible to isolate in vitro.
2. Many organisms are species specific and some only infect humans.
3. Some diseases are synergistic infections caused by several microorganisms.
4. Some microorganisms become altered when cultured in vitro.

Edward Jenner

1. created the first vaccine
* smallpox/cow pox

Paul Ehrlich

1. father of chemotherapy
2. variations of arsenic derivatives used to treat syphillis

Alexander Fleming

1. discovery of antibiotics
* Penicillin

Rebecca Lancefield

1. proposed that streptococci be classified based on serotypes
* due to differences in chemical composition of polysaccharides in the cell wall