Suffolk Community College
Eastern campus
General Microbiology- BIO244
CRN 23083 Section # 400
Spring 2016
Instructor: Adriana Pinkas, PhD
Web site: http:/www2.sunysuffolk.edu/pinkasa
Email: pinkasa@sunysuffolk.edu
Chapter 1
The Microbial World And You
What is a microorganism?
(micro-organism)
• Organism that is too small to be seen with the naked eye.
–micro - is a prefix in the International System of Units and other
systems of units denoting a factor of 10−6 (one millionth) meter.
Symbol- µ
– organism – a form of life
• Life is a condition that distinguishes organisms from inorganic objects
• Life fundamental feature:
– growth
– reproduction
– adaptation to the environment through changes originating internally
Microbiology is the study of microscopic organisms
Based on their similarity and difference all organisms are organized in
The Three-Domain System.
Eukarya
Bacteria
Animals
Fungi
Origin of mitochondria
Amebae
Mitochondria
Slime molds
Cyanobacteria
Proteobacteria
Chloroplasts
Achaea
Plants
Extreme
halophiles
Methanogens
Ciliates
Green
algae
Dinoflagellates
Diatoms
Hyperthermophiles
Gram-positive
bacteria
Euglenozoa
Giardia
Thermotoga
Mitochondrion degenerates
Origin of chloroplasts
Horizontal gene transfer
occurred within the
community of early cells.
Nucleoplasm grows larger
Ancestors of bacteria were the first life on Earth.
Classification of Microorganisms
• Three domains
• Bacteria
• Archaea
• Eukarya
} Prokaryotic
• Protista
• Protozoa
• Algae
• Fungi
• Viruses
}
Eukaryotic
Acellular
Bacteria
• Prokaryotic -they have no nucleus
• Unicellular organisms.
• Cell wall - peptidoglycan
• Divide by binary fission
• For energy, use:
• organic chemicals
• inorganic chemicals
• or photosynthesis
• Free living
• 3 common shapes:
• Bacillus
• Coccus
• Spiral
Figure 1.1a
Archaea
• Prokaryotic
• Unicellular organisms.
• Cell wall - Lack peptidoglycan
• (pseudomurein)
• Divide by binary fission
• For energy, use:
• Organic
• Inorganic
• photosynthesis
• Free living
• Live in extreme environments
• Methanogens
• Extreme halophiles
• Extreme thermophiles
Figure 4.5b
Eukarya - Fungi
• Fungi (mushrooms, molds, and yeasts)
have a true nucleus and they are
eukaryotic cells
• Yeasts are unicellular
• Molds and mushrooms are multicellular
• consisting of masses of mycelia, which are
composed of filaments called hyphae
• Cell walls - Chitin
• Reproduction – asexual and sexual
(mitosis or meiosis)
• For energy, use organic chemicals
• obtain nutrition by absorption
• Free living
Figure 1.1b
Eukarya – Protista - Protozoa
• Protozoa are eukaryotes.
• Unicellular
• Have no cell wall
• pellicle - a thin layer supporting the cell
membrane in various protozoa
• Reproduction – asexual and sexual
(mitosis or meiosis)
• Free living or parasites
• For energy, use organic chemicals
• Protozoa obtain nutrition by absorption or
ingestion through specialized structures.
Figure 1.1c
Eukarya – Protista - Algae
• Eukaryotes
• Unicellular, filamentous, or
multicellular (thallic)
• Cell walls - Cellulose
• Reproduction – asexual and sexual
(mitosis or meiosis)
• Free living
• Use photosynthesis for energy
• Produce molecular oxygen and organic
compounds
Figure 1.1d
Viruses
• Acellular
• Consist of DNA or RNA core
• Core is surrounded by a protein coat
• Coat may be enclosed in a lipid
envelope
• Reproduction – use host resources
• Viruses are replicated only when
they are in a living host cell
• Obligate cellular parasite
Figure 1.1e
Naming and Classifying Microorganisms
• Binomial nomenclature - Carlous
Linnaeus 1735 established the
system of naming specific species.
• Each organism has two names:
• The genus
• Specific epithet.
• Are “Latinized” and used worldwide.
• May be descriptive or honor a scientist.
• Names are written in italics or underlined.
• The Genus is capitalized and the specific
epithet is lower case.
Scientific names
• Staphylococcus aureus
– Genus - Staphylococcus - describes the
clustered arrangement of the cells (staphylo-)
– Specific epithet – aureus - the golden color of the colonies.
• Escherichia coli
– Genus – Escherihia -Honors the discoverer, Theodor Eshcerich
– Specific epithet – coli - describes the bacterium’s
habitat, the large intestine or colon.
• After the first use, scientific names may be abbreviated with the
first letter of the genus and the specific epithet:
Staphylococcus aureus and Esherichia coli are found in the human body. S.
aureus is on skin and E. coli, in the large intestine.
A Brief History of Microbiology
In 1665, Robert Hooke - introduced the term cells
- observed that cork was composed of “little boxes”
1673-1723, Anton van Leeuwenhoek - first described live
microorganisms
- observed teeth scrapings, rain water, and peppercorn infusions - ”animalcules”
A Brief History of Microbiology
• The Debate Over Spontaneous Generation
• Spontaneous Generation theory:
•
Living organisms arise from nonliving matter, a “vital force’
forms life
• Biogenesis hypothesis
Living organisms arise from preexisting life
–In 1858, Rudolf Virchow challenged the spontaneous
generation theory with the concept of biogenesis
Cell Theory
All living things are composed of cells and come from preexisting
cells
1861, L.Pasteur - Pasteur’s S-shaped flask kept microbes out but let air in.
Figure 1.3 Disproving the Theory of Spontaneous Generation.
Pasteur first poured
beef broth into a
long-necked flask.
Next he heated the neck
of the flask and bent it
into an S-shape; then he
boiled the broth for
several minutes.
Microorganisms did not
appear in the cooled solution,
even after long periods.
Bend prevented microbes
from entering the flask.
Microorganisms were
present in the broth.
Microorganisms were
not present even after
long periods.
Microorganisms were not present
in the broth after boiling.
1. Microorganism can be present in nonliving mater
2. Microbial life can be destroyed by heat
3. That methods can be devised to block the access of airborne
microorganisms to nutrient environment.
Louis Pasteur (1822-1895)
1. Disproving
spontaneous generation - The air by itself does
not create microbes
2. Father of aseptic technique
• Techniques that prevent contamination by unwanted microorganisms
• Modern aseptic techniques are among the first and most important
things a beginning microbiologist learns
3. Invent Fermentation and Pasteurization
• Fermentation – some microorganisms (yeasts) are responsible for the
conversation of sugar to alcohol to make beer and wine.
• Microbial growth is also responsible for spoilage of food.
• Bacteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar
(acetic acid).
• Pasteurization - application of a high heat for a short time
– Demonstrated that the spoilage bacteria could be killed by heat that was not hot
enough to evaporate the alcohol in wine.
4. The relationship between microbes and disease
• 1865 Pasteur believed that a silkworm disease was caused by a protozoan.
• 1860s: Joseph Lister - ‘Father of Antiseptic Surgery’
• Used a chemical disinfectant (carbolic acid )
to prevent surgical wound infections (1876)
• Development of vaccines
• 1796: Edward Jenner inoculated a person with cowpox virus. The person was
then protected from smallpox.
• Called vaccination from vacca for cow
• 1880: L.Pasteur select avirulent strains used for vaccine.
• The role immunity in cure of disease
• The protection from disease provide by vaccination is called immunity
The Germ Theory of Disease - Robert Koch
• Robert Koch isolated:
• Bacillus anthracis (1877)
• Tuberculosis bacillus (1882)
• Vibrio cholerae (1883)
• Provided proof that a specific microbe
causes a specific disease.
• 1883: Koch’s postulates which say that
to establish that an organism is the cause
of a disease, it must be:
• found in all cases of the disease examined
• prepared and maintained in a pure culture
• capable of producing the original infection,
even after several generations in culture
• be retrievable from an inoculated animal
and cultured again.
The Birth of Modern Chemotherapy
• Chemotherapy - treatment of disease with chemical substances
• Quinine from tree bark was long used to treat malaria.
• 1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to
treat syphilis.
• 1930s: Sulfonamides were synthesized.
• 1928: Alexander Fleming discovered the first antibiotic.
• He observed that Penicillium fungus made an antibiotic, penicillin, that killed
S. aureus.
• 1940s: Penicillin was tested clinically
and mass produced
Modern Developments in Microbiology
• Microbial genetic study of how microbes inherit traits
• genes encode a cell’s enzymes (1942)
• DNA was the hereditary material (1944).
• the role of mRNA in protein synthesis (1961).
• Molecular biology is the study of how DNA directs protein synthesis
• Genomics: the study of an organism’s genes; has provided new tools
for classifying microorganisms
• Recombinant DNA: DNA made from two different sources
Modern Developments in Microbiology
• Bacteriology is the study of bacteria and archaea.
• Mycology is the study of fungi.
• Parasitology is the study of protozoa and parasitic worms.
• Phycology is study of algae
• Virology is the study of viruses.
• Immunology is the study of immunity.
Microbes and Human Welfare
Are they good or bad?
1. Microorganisms are important in the maintenance of an ecological
balance on Earth.
• Microbial Ecology
• Bacteria recycle carbon, nitrogen, sulfur, and phosphorus that can be used by
plants and animals.
• Bacteria degrade organic matter in sewage.
• Bacteria degrade or detoxify pollutants such as oil and mercury
• Bioremediation
• The use of bacteria, fungi, green plants or
their enzymes to remove or reduce
human-made pollution.
• Main principal – to enhance activity of the naturally
occurring organisms that can perform bioremediation
• Insect pest control - GMO
Microbes and Human Welfare
2. Some microorganisms are used to produce foods and chemicals.
• Biotechnology
• the use of microbes to produce foods
and chemicals, is centuries old.
• Genetic engineering - use of recombinant DNA technique for
modern biotechnology.
• Bacteria and fungi can produce a variety of proteins
including vaccines, human hormones and enzymes
• Genetically modified bacteria are used to protect
crops from insects and freezing
• Missing or defective genes in human cells
can be replaced in gene therapy.
Microbes and Human Welfare
3. Some microorganisms normally present (live) in and on the
humans and other animals and are needed to maintain good health
- Normal Microbiota (microflora)
Microbes and Human Welfare
Microbiome - the combined genetic material of the microorganisms
in a particular environment ( human body)
• Gut microbiome – “forgotten organ”
• Produce hydrolytic enzymes - help our digestive
system
• Synthesize vitamins – K, B2, B12 and folic acid
• Skin and gut microbiome
• Stabilize epithelial homeostasis and barrier function
• Modulate our innate and adaptive immunity
• Prevent growth of pathogens
• Production of antimicrobial substances
• Compete for the nutrients
Some microorganisms cause disease
• Pathogen – "that which produces suffering.“- causes infection
disease
• Infection disease – presence of particular microorganism in part of the
body where is not usually found.
• Resistance is the ability of the body to ward off disease.
• When a pathogen overcomes the host’s resistance, disease results.
• Emerging Infectious Diseases (EID): New diseases and diseases
increasing in incidence
Where do microorganisms live ?
• Microorganisms are found in almost every habitat present in nature
•
•
•
•
•
•
Soil
Hot springs
Oceans
High in the atmosphere
Deep inside rocks within the Earth's crust
On and in other organisms bodies
Why can they live in every environment ?
• Present all types of metabolism (use different sources of carbon and energy)
• Reproduce rapidly
• They are very adaptive
How microorganisms are connected to our lives?
• Primary producers in the ecosystems - food chain, oxygen
• Decompose organic waste
• Produce fermented foods such as vinegar, cheese, and bread
• Produce industrial chemicals such as ethanol and acetone
• Used in manufacturing to produce products for industry (e.g.,
cellulase) and disease treatment (e.g., insulin)
• Some are pathogenic (disease-causing)
How the knowledge of microorganisms helps us?
• Led to aseptic techniques to prevent contamination in medicine and in
microbiology laboratories
• Allows humans to prevent food spoilage
• Prevent disease occurrence and treat diseases
• May be will help us to save the planet
Learning objectives
• Recognize the system of scientific nomenclature that uses two names: a
genus and specific epithet.
• Differentiate among the major characteristics of each group of
microorganisms.
• List the three domains.
• Compare spontaneous generation and biogenesis.
• Identify the contributions to microbiology made by Hooke, van
Leeuwenhoek, Virchow, Pasteur, Lister, Koch, Jenner, Ehrlich, and
Fleming.
• Define bacteriology, mycology, parasitology, immunology, and virology.
• List beneficial activities of microorganisms.
• List harmful activities of microbes
• Define normal microbiota and resistance.