Transcript Fig. 1-6 - Indiana University Northwest

• As with anything you choose to do well,
success in this class will require a
significant input of time and thought on
your part – 4 to 8 hours a week plus class
and lab time. Please do not assume
listening to me during lecture and cramming
for the tests will be sufficient.
• Read the chapter before each lecture (do not read in depth, note the
headings and the words written in bold. Attendance is mandatory for
success. Listen, ask questions, and take notes. Go over your notes and
re-read portions of the chapter as quickly after class as possible.
Focus only on the areas covered by the notes (slides). Go over the
figures in the book (slides). Memorize any terms and words you were
not familiar with. Make an outline, answer questions in the book (both
in chapters and at the end of each chapter), and explain each concept or
term to a friend/enemy. Then read the section we will be covering for
the next lecture. If you do not understand something, come to my
office and ask for help immediately, not the day before the test!! If you
can not come during my office hours please make an appointment to
see me. For each test review the slides, terms, and your outline. Tutor
a friend, explain concepts and test each other.
• Grading policies:
• Tests can include fill in the blanks, true and false, short answers, essay,
multiple choice… and vary widely from test to test.
• Questions often require that you use your knowledge to answer
questions on subjects we did not specifically cover in class. This
requires that you understand the material.
• If you miss a test, you must make arrangements to take that test within a
week. If you miss two, 5 % will be subtracted from your test score. If
you miss three tests, 10% will be subtracted. Attendance is mandatory
for success
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Grading is not curved.
90-100% = A
80-89% = B
70-79% = C
60-69% = D
50-59% = F
Lab is 25% of your grade.
• Each day before or after lecture, a quiz may be given
covering the lectures before. These quizzes will be as
much as 20% of your grade. Therefore, go over your notes
and re-read portions of the chapter as quickly after class
as possible. Focus only on the areas covered by the notes
(slides). Go over the figures in the book (slides).
Memorize any terms and words you were not familiar
with. Make an outline, answer questions in the book (both
in chapters and at the end of each chapter), and explain
each concept or term to a friend/enemy.
• Use the web site for useful chapter outlines, quizzes, etc:
www.wiley.com/college/black/.
• Do the questions at the end of the chapter. The deadline
will always be one class period after we finish the chapter.
• Importance of Microbiology
– Microorganisms are almost everywhere, they are part of
the human environment and are important to human
health
• are essential to the web of life
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capture energy from sunlight
decompose dead organisms
make nitrogen available to plants
essential links in food chains
» digestive tracts of grazing animals - aid in digestive
processes
essential in food industry
» pickles, yogurt, etc.
synthesize antibiotics
tools for genetic engineering - produce insulin etc.
degrade oil spills, etc.
• Importance of Microbiology
– are essential to the web of life
– provide insight into life processes in all life forms
• useful in research
– because they are relatively simple
– reproduce rapidly
– large numbers can be used to obtain statistically reliable results
• useful in research
– how matter is decomposed
– metabolic pathways
– how hereditary information is transferred
– some cause disease in humans, animals, and plants
• learn how diseases are transmitted, diagnosed, and prevented
• vaccines have nearly eradicated several dreded childhood
diseases - measles, polio, etc.
Microbiologists study 5 major
groups of organisms:
bacteria (prokaryotes),
(eukaryotes) algae,
fungi, protozoa, and
viruses (acellular*).
Most microbes studied
are unicellular*. They range
from viruses at 20nm to large
protozoans at 5mm or more in
diameter (250,000 Xs as
large).
*Cells are the basic units of
structure and function of all
living things.
Bacteria are prokaryotes. They
have no membrane bound
organelles - no nucleus. Bacteria
come in all shapes, mainly rods,
spheres, and spiral shapes. These
are rod shaped bacterium that can
cause pneumonia in humans. Pg7.
Algae, fungi, and protozoa
are eukaryotes. They are
larger and more complex
than bacteria. They contain
membrane bound organelles,
including a nucleus.
Algae can be single-celled or relatively large and complex
multicellular organisms. All algae photosynthesize their own food,
as plants do. Only one species causes disease in humans
Fungi such as yeasts and some
molds are single-celled.
However, others such as
mushrooms are multicellular
macroscopic organisms. Fungi
are eukaryotic, with membranebound organelles. All fungi
absorb ready-made nutrients
from their environment. They
decompose dead organisms.
Some cause disease or are
sources of antibiotics.
These are fruiting bodies of a fungus with
black spore packets on top that will be shot into
the air to colonize new areas.
Viruses are acellular, made up of a nucleic acid and a few proteins.
They replicate in cells and can cause disease. These are
bacteriophage, viruses that invade bacteria.
Protozoa are single-celled,
microscopic eukaryotic
organisms. Most ingest
smaller microorganisms and
most can move. Some
protozoa cause human
disease - malaria
Also covered are helminths
(worms) and arthropods
(insects) since helminths
have microscopic states in
their life cycles which can
cause disease and insects
transmit these stages as well
as other microbes.
This is an amoeba.
• Naming bacteria
– two names: their genus and species names
• Escherichia coli (E. coli)- lives in your gut
• Giardia intestinalis - causes severe diarrhea
• Naming viruses
– named for the group - herpesviruses
– named for the disease they cause - polioviruses
• Table 1.1
– know 5 bacterial diseases and five viral diseases.
• CDC = Centers for Disease Control and
Prevention, a federal agency that collects data
about diseases and ways to control them.
• Fields of Microbiology
– organisms studies
• bacteriology
• phycology
• mycology
bacteria
algae
fungi
protozoology
parasitology
virology
protozoa
parasites
viruses
– processes or functions studied
• microbial metabolism-chemical reactions occuring in microbes
• microbial genetics-transmission of genetic information
• microbial ecology-relationships with each other & the environment
– health-related fields
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immunology-how host organisms defend against infection
epidemiology-frequency and distribution of diseases
etiology-causes of disease
infection control
chemotherapy
– applications
• food and beverage protection, environmental-safe drinking water, etc.
Table 1-2
See checklist page 10
The first person to observe and describe microorganisms accurately was
Antony van Leeuwenhoek.
Eventually led to
the cell theory
which states that
cells are the
fundamental units
of life and carry
out all the basic
functions of living
things.
Spontaneous generation
• Believed from earliest times, that living organisms
could develop from nonliving matter.
• As long as scientists believed microorganisms
could arise from nonliving substances, they did
not consider how diseases were transmitted or
how they could be controlled.
• Disproving this belief was necessary and as with
all long held beliefs, it took a long time.
Fig. 1-6
Disproved for macro-organisms by Redi
He placed meat in three containers, one uncovered, one covered with
paper, and one covered with a fine gauze (allowing air in but not
flies). Maggots developed on the meat only in the uncovered
container. They developed on the gauze, but not on the meat.
Showing that the eggs came from flies, and maggots do not
spontaneously appear.
Pastuer placed
nutrient solutions
in flasks, heated
and bent their
necks into curves
while keeping the
ends open to the
atmosphere.
(Some thought
“air” or the “life
force” in air was
needed for
spontaneous
generation.) No
bacterial growth
Other experiments had been done to disprove spontaneous generation
of microbes, but many still argued that altering the air prevented of
microorganisms
Disproved by Pasteur for microorganisms
Air and
microbes
entered the
curved tubes,
but microbes
were trapped in
the curves of
the neck and
never reached
the broth.
• Germ theory of disease states that microorganisms can
invade other organisms and cause disease.
• Pasteur’s work in the wine and silk industry demonstrated
that certain microorganisms caused disease. Pasteur also
developed a rabies vaccine.
• Lister develops antiseptic surgery which prevents infection
– heat sterilized instruments and phenol on surgical dressings
• Koch proposes criteria to establish relationship between
microbe and disease - Koch’s postulates
– 1. The microorganism must be present in every case of disease (and
absent from healthy organisms)
– 2. The suspected microorganisms must be isolated and grown in pure
culture (see next slide)
– 3. The same disease must result when it is inoculated into a healthy host.
– 4. The same microorganism must be isolated again from the diseased
host.
• Early techniques for studying microbial pathogens introduced by Koch
include
– agar as a solidifying agent on which to grow the microbes
– Media suitable for growing bacteria, meat extracts and protein
digests lead to nutrient broth and nutrient agar used today
• Solid media allows for isolation of pure colonies, important in the
study of microbes and the determination of pathogenicity. See box on
page 16 “last drop”.
See checklist page 17
• Special Fields of Microbiology Table 1.2
– Immunology is the study of the host’s responses to
protect against microbial invasion.
• Vaccination was the first step in recognizing that the host
immune system “did something” to protect from and remember
a pathogen.
– Chinese knew that a person who survived smallpox was
protected. They ground up dried scabs and inhaled the weakened
organisms to protect themselves from smallpox.
– Jenner realized that milkmaids got cowpox (milder than small
pox) but they did not get smallpox, they were protected. He
inoculated an 8 year old with cowpox, then later with small pox
(!!!). The boy did not get sick (lucky for Jenner)
– Pasteur also worked on vaccines, especially known for rabies. He
reasoned that the microbes had lost their ability to induce disease,
but retained their ability to induce immunity.
• Phagocytes = cells that “eat” other cells or parts of cells.
Metchnikoff discovered that phagocytes are important in
protection against infection. See box on page 18.
•Special Fields of Microbiology Table 1.2
•Virology
•Once a porcelain filter was developed to remove bacteria from water
etc, it was found that some infectious agents could get through the
filter. These were found to be viruses.
•Viruses consist of protein and nucleic acid (RNA or DNA) and can
replicate and “live” only in host cells, using the cells chemical
machinary.
Development of techniques for isolating, growing, and
analyzing viruses has led to the isolation and characterization
of many viruses. Some have been crystallized.
Viruses can be seen using an electron microscope.
See Box on page 18 - mosquitoes
Tobacco mosaic virus
Fig. 1-13
• Special Field of Microbiology
– Chemotherapy
• Substances derived from plants - digitalis, ephedrine, morphine
- have been used by cultures like Native Americans
• Ehrlich recognized that certain dyes stained microbes and not
animal cells, suggesting that dyes or other chemicals might
selectively kill microbes. Began systematic search
• Other substances made by the body itself, lysozyme in tears,
were discovered
– Antibiotics = substances that kill bacteria and are made
by bacteria or mold (Penicillium) - Fleming
• Difficult to purify in sufficient quantities until WWII
• Searched soil samples for growth-inhibiting microorganisms or
their products. Still today.
• Special Field of Microbiology
– Genetics and Molecular Biology
• Most of the key discoveries that led to our present
understanding of genetics emerged from research with
microbes
• genetic engineering converts bacteria into factories that
produce drugs, hormones, vaccines, etc.
• Microbes, viruses in particular, are often used to insert new
genes into other organisms, even into human cells
– ex. Immune deficiency corrected in a 4 yr old girl. Normal copy
of the mutated gene was inserted into some of here white blood
cells in the laboratory and then the treated cells were injected
back into her body. These cells then restored her immune
system.
• Microbial genetic techniques have made possible the Human
Genome Project, finished ahead of schedule, May 2000.
The scientific method
Box on page 21
How Microbiologists
Investigate Problems
Do the questions in the back of the
chapter. Deadline for handing them
in will always be one class period
after we are finished with the
chapter. Correct them yourself first.
observations