Transcript Biology 261 Microbiology and Immunology for Health profession

Biology 261
Microbiology and Immunology for
Health profession
Prof. Victor Santos
Medgar Evers College, CUNY
Microbiology - study of microorganisms.
Microbiology is a broad term or field that
includes others branches.
• Branches of Microbiology
1. Bacteriology – study of bacteria
2. Mycology – study of fungi
3. Phycology- study of
algae
4. Protozoology – study of protozoa
5. Virology - study of viruses
6. Parasitology – study of parasites
Members of the microbial world
• All organisms can be placed in one of three
large groups known as Domains. These
domains are Bacteria, Archaea, and Eucarya.
• Members of the microbial world include
organisms from all domains.
Bacteria
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Are prokaryotes
Unicellular
Three basic shapes; rod, sphere, and spiral.
Divide by binary fission
Diverse in terms of habitat
Have a cell wall that consists of a
macromolecule called peptidoglycan.
• Most bacteria are motile and can move by
means of an appendage called a flagellum.
Archaea
• Similar to bacteria in terms of size, shape, and
replication.
• Three main differences are
1- Biochemistry of the cell wall. Peptidoglycan
is not found in the cell wall of archaea.
2- the presence of ether lipids in the cell
membrane.
3- Archaea are also known for their ability to live
in extreme environments. Some can withstand
high salt level (halophiles), extreme heat
(thermophiles), and extreme cold (cryophiles).
• Halophiles- salt halococcus
• Thermophiles- heat thermus aquaticus
• Cryophiles- cold ocean water arthrobacter
Halobacteria
Eucarya
• Are eukaryotes
• Include unicellular organisms and multicellular
organisms that cause disease.
• These include algae, protozoa, fungi and multicellular animals such as arthropods and
helminths.
Algae
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Unicellular or multi-cellular
Photosynthetic
Live in either salt or fresh water
Cell wall is composed of cellulose
Algae do not directly cause disease in humans
but do so indirectly by secreting toxins that are
consumed by marine life eaten by humans.
Cyanophyta recovered from Lake
Champlain
Protozoa
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Eukaryotes
Unicellular
are both terrestrial and aquatic in nature
Have no cell wall
are classified according to their mode of
motility; pseudopods, cilia, or flagellum.
Euglena
Fungi
• Eukaryotes
• Unicellular or multi-cellular
• Gain their energy by breaking down organic
materials.
• Mostly terrestrial in nature
Amanita muscaria
Large multi-cellular animals
2 groups of larger multi-cellular animals are
also included in our study because they cause
disease in humans and we can apply the same
immunological and microscopic techniques to
study them. These are the arthropods and
helminths.
Arthropods
• Include insects such as mosquitoes, fleas, and
lice. Also included are ticks and mites which
are arachnids. Arachnids differ from insects in
that they lack wings, antenna, and their thorax
and abdomen are fused together.
• Arthropods are mainly vectors such as
mechanical or biological. They are known as
disease carriers!
Helminths
• Are parasitic in nature
• Include tapeworms, roundworms, and flukes.
• Unlike the arthropods that only act as vectors
to spread disease, the helminths can cause
serious diseases in humans.
• Helminths include the roundworms
(nematodes), tapeworms (cestodes), and the
flukes (trematodes).
roundworm
Infectious agents
Virus
• A piece of nucleic acid surrounded by a
protein coat
• They are obligate intracellular parasites
• They infect all forms of life.
Viroid
• A single short piece of nucleic acid,
specifically RNA.
• They can only reproduce inside a cell
• Are known to cause diseases in plants
• Prions
• Agents that consists of only proteins that
have been known to cause
neurodegenerative diseases in humans
and other animals and are usually fatal.
Beneficial applications of microorganisms
A. Normal flora
1. Beneficial metabolic functions
2. Antagonistic effect - prevents invasion pathogens, over
growth of potential pathogens
B. Environmental importance
1. Decomposers
2. Produce oxygen
3. Food chain
C- Food/beverage production
1- Microorganisms are used in the production of such foods as
bread, cheese, yogurt, buttermilk and probiotics
2- The brewery industry depends on microorganisms for the
production of beer and other fermented drinks
D- Bioremediation
1- microorganisms are used to break down dangerous
pollutants such as PCB (polychlorinated biphenyls), DDT, and
trichloroethylene.
2- microorganisms are also used to break down oil, and
radioactive waste.
E- Products
1- Cellulose
2-Hydrobutyric acid used in the production of disposable diapers
and plastics
3-Antibiotics used in treatment of disease
F- Molecular Biology studies
1- Microorganisms serve as model organism to study more
complex life forms.
2- genetic engineering to manipulate organisms and produce
useful products
History of Microbiology
Anton van Leeuwenhoek (1674)
1. Used simple instrument to examine
stagnant H2O, etc.
2. Observed microscopic organisms and
is credited with being the first to observe
bacteria.
Theory of Spontaneous Generation
1. This theory existed to explain the origin of
some forms of life
2. Living organisms arose “spontaneously”
from nonliving, decaying organic matter.
3. This theory was formulated by Aristotle.
• Francesco Redi
1.Performed experiments that disproved
theory of SG for more complex forms of
life (began approx.1668).
Louis Pasteur (1861)
1. Performed experiments to disprove Theory of SG.
a. He accepted the challenged to re-create the
experiment and leave the system exposed to air.
b. Placed boiled infusion broths in “swan-necked”
flasks
c. Flasks remained sterile unless tilted or neck broken.
2. His experiments finally disprove the theory of SG.
John Tyndall (1875)
• English physicist who finally explained the
differences in the previous experiments. He
concluded that different organisms required
different boiling temperatures to be sterilized.
• He stated that organisms can exist in a cell
state easily killed by boiling and a heat
resistant form.
• One year later Ferdinand Cohn discovered
endospores.
Golden Age of Microbiology (approx. 1875 1918)
1.Period (about 50 years) of rapid development.
2.Causes of diseases identified, control methods
developed, work began on viruses.
Robert Koch
While studying anthrax ( a disease of cattle)
a. Identified a bacterium as cause of anthrax (first
bacterium that caused a disease).
b. Introduced “solid medium” using agar, observed
differences in colony morphology and Introduced the
inoculating loop to transfer bacteria and prepare pure
cultures.
c. Introduced “Koch’s Postulates” and the concept
that a disease is caused by a single organism.
Joseph Lister (1865)
a. Introduced the “aseptic technique” to the
field of Microbiology.
b. Use of phenol (carbolic acid) as
disinfectant.
Size in the microbial world
• Members of the microbial world cover a
tremendous range in their sizes. They range in
size from mm to nm.
• The basic unit of length is the meter