Biology of microorganisms Biology

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					Biology of microorganisms

         Zhao Bin and He shaojiang
  The college of Life Science and Technology
      Huazhong Agricultural University
What’s the arrangement for
the teaching?

           Why should we study microbiology

               How to use your textbook?

•   Lecture (70 hours)
•   Laboratory practice (50 hours)
•   Mini-test (10 times)
•   Open-laboratory practice
•   Club activity
Why should we study microbiology?
            Two major reasons

As a basic                    As an applied
biological science            biological science

  Provides research tools
  Biochemical and genetic study
  microbiology deals with many important
  practical problems in medicine, agriculture,
  and industry.
                We will discuss:

• the experimental basis of microbiology
• the general principles of cell structure and function
• the classification and diversity of microorganisms
• biochemical processes in cells
• the genetic basis of microbial growth and evolution
• the ecological activities of microorganisms in nature.
            How to use your textbook ?

      (Brock Biology of Microorganisms, Ninth Edition)

The CHAPTER OUTLINE provides an overview of the chapter’s
main concepts.

SECTION NUMBERS     keyde to page numbers provide easy
reference points.

The WORKING GLOSSARY provides definitions of important terms
within each chapter.
TABLEShave been redesigned to make key information even
more accessible to students.

CONCEPT CHECKS   summarize each section and provide quiz
questions, so students can evaluate their understanding as
they progress through the chapter.

CONCEPT LINKS alert students to material that builds on
previous concepts and provides a useful cross-referencing
system for the entire book.

Outstanding MICROGRAPHS are included throughout.
FEATURE BOXES  provide additional, relevant information.
Some take an historical perspective, some focus on
techniques and applications, and others explore a text topic
in greater depth.

BOLDFACED TERMS   are defined in the Glossary.

The ART  in the ninth edition has been thoroughly revised,
but still maintains the use of consistent color coding.
REVIEW QUESTIONS challenge the student’s mastery of
chapter concepts.

APPLICATION QUESTIONS allow students to test their
analytical and problem-solving skills.

APPENDICES   provide useful tutorial and reference information.
A very effective study technique to you

           Read                    Revise

Question          SQ4R Technique        Record

     Survey                        Review

                     To continue
Briefly scan the chapter to become familiar with its
general content. Quickly read the title, introduction,
summary, and main headings. Record the major
ideas and points that you think the chapter will make.
If there are a list of chapter concepts and a chapter
outline, pay close attention to these. This survey
should give you a feel for the topic and how the
chapter is approaching it.
As you reach each main heading or subheading, try
to compose an important question or two that you
believe the section will answer. This preview
question will help focus your reading of the section.
It is also a good idea to keep asking yourself
questions as you read. This habit facilitates active
reading and learning.
Carefully read the section. Read to understand
concepts and major points, and try to find the
answer to your preview question(s). You may
want to highlight very important terms or
explanations of concepts, but do not
indiscriminantly highlight everything.
After reading the section, revise your question(s)
to more accurately reflect the section's contents.
These questions should be concept type questions
that force you to bring together a number of
details. They can be written in the margins of
your text.
Underline the information in the text that answers
your questions, if you have not already done so.
You may wish to write down the answers in note
form as well. This process will give you good
material to use in preparing for exams.
Review the information by trying to answer your
questions without looking at the text. If the text has a
list of key words and a set of study questions, be sure
to use these in your review. You will retain much
more if you review the material several times.
                     CHAPTER 1

  Microorganisms and Microbiology

1.1 What is a microbe?
1.2 The importance of Microbiology
1.3 Microbes in our lives
1.4 The history of microbiology
1.5 Important events in the development of microbiology
    1.1 What is a microbe?

The word microbe (microorganism) is used to describe
an organism that is so small that, normally, it cannot be
seen without the use of a microscope. Viruses, bacteria,
fungi, protozoa and some algae are all included in this
  Our world is populated by
invisible creatures too small to
be seen with the unaided eye.
These life forms, the microbes or
microorganisms, may be seen
only by magnifying their image
with a microscope.
                          Microbial world

             Organisms                         Infectious agents
             (living)                          (non-living)

  Prokaryotes            eukaryotes          viruses      viroids      prions

Eubacteria     Archaea    Algae           Fungi           Protozoa      Other
                          (unicellular    (unicellular    (unicellular) multicellular
                          or              or                            organisms
                          multicellular   multicellular
The size and cell type of microbes
                                             Most of the bacteria,
                                             proto- zoa, and fungi
                                             are single-celled
microbe    Approximate          Cell type    microo rganisms, and
           range of sizes                    even the multicelled
Viruses    0.01-0.25µm          Acellular    microbes do not have
Bacteria   0.1-10µm             Prokaryote   a great range of cell
           2µm->1m              Eukaryote
                                             types. Viruses are not
                                             even cells, just genetic
Protozoa   2-1000µm             Eukaryote
                                             material surrounded
Algae      1µm-several meters   Eukaryote    by a protein coat and
                                             incapable of
                                             independent existence.
 1.2 The importance of microbiology
Microbes impinge on all aspects of life, just a few of
these are listed below:

The environment           Medicine            Food

         Biotechnology             Research
1. The environment
2. Medicine
3. Food
4. Biotechnology
                     Press here to continue
5. Research
 Microbes are responsible for the cycling of carbon,
nitrogen and phosphors (geochemical cycles), all
essential components of living organisms (Topic FI).
They are found in association with plants in symbiotic
relationships, maintain soil fertilitv and may also be
used to clean up the environment of toxic compounds
(bio-remediation; Topics H6 and 14). Some microbes
are devastating plant pathogens (Topic H7), which
destroy important food crops, but others may act as
biological control agents against these diseases.
The disease-causing ability of some microbes such as
smallpox. (Variola virus; Topic KS), cholera (Vibrio
cholera bacteria; Section F3) and malaria (Plasmodium
protozoa, Topic J7) is well known. However, micro-
organisms have also provided us with the means of their
control in the form of antibiotics (Topic F7) and other
medically important drugs.
Microbes have been used for thousands of years, in
many processes, to produce food, from brewing and
wine making, through cheese production and bread
making, to the manufacture of soy sauce (Topic F2).
At the other end of the scale, microbes are responsible
for food spoilage, and disease-causing microbes are
frequently carried on food (Topic F5).
Traditionally microbes have been used to
synthesize many important chemicals such
as acetone and acetic acid (Topic F2). More
recently he advent of genetic engineering
techniques has led to the cloning of
pharmaceutically important polypeptides
into microbes, which may hen be produced
on a large scale.
Microbes have been used extensively as model
organisms for the investigation of biochemical and
genetical processes as they are much easier to work
with than more complex animals and plants. Millions
of copies of the same single cell can be produced in
large numbers very quickly and at low cost to give
plenty of homogeneous experimental material. An
additional advantage is that most people have no
ethical objections to experiments with these
                  Microbial physiology

   Microbial genetics              Microbial Morphology

 Virology                                     Parasitology

Mycology                Microbiology          Protozoology

                                          Microbial ecology

Microbial taxonomy                     Molecular biology

                 Phycology or Algology
1.4 The history of microbiology
 The discovery of microorganisms

 The spontaneous generation conflict

 The recognition of microbial role in

 The discovery of microbial effects on
 organic and inorganic matter

 The development of microbiology in this
   The discovery of microorganisms

Antony van Leeuwenhock

 The first person to
accurately observe and
describe microorganisms
The first person to observe and describe
microorganisms was the amateur microscopist
Antony van leeuwenhoek of Delft, Holland.

Leeuwenkoek made his simple, single-lens
microscope which could amplify the object being
viewed 50 – 300 times. Between 1673 – 1723, he
wrote a series of letters to the Royal Society of
London describing the microbes he observed from
the samples of rainwater, and humam mouth.
 being      A drawing of one of
 viewed     the microscopes
adjusting   showing the lens a;
 screws     mounting pin b; and
            focusing screws c
            and d.

            drawings of bacteria
            from the human
        Louis Pasteur (1822 – 1895)

  Pasteur’s contributions:
• Final refutation of
  spontaneous generation –
  birth of microbiology as a
• Discovery of the existence
  of anaerobic life –
• Vaccines
• Pasteurization             Louis Pasteur working in his laboratory
1. Pasteur (1857) demonstrated that lactic acid
   fermentation is due to the activity of

2. Pasteur (1861) conflict over spontaneous
   generation – birth of microbiology as a

3. Pasteur (1881) developed anthrax vaccine

4. Pasteurization
The spontaneous generation conflict

Spontaneous generation – that living
organisms could develop from nonliving or
decomposing matter.
Pasteur’s swan neck flasks used in his experiments
on the spontaneous generation of microorganisms
 Microorganisms are not spontaneously
 generated from inanimate matter, but are
 produced by other microorganisms
        Robert Kock (1843 – 1910)

The recognition of microbial role in disease

          Robert Kock in his laboratory
               Kock’s postulates

1. The microorganisms must be present in every
   case of the disease but absent from healthy
2. The suspected microorganisms must be isolated
   and grown in a pure culture.
3. The disease must result when the isolated
   microorganisms is inoculated into a healthy host.
4. The same microorganisms must be isolated again
   from the diseased host
The Golden age of microbiology

    • Koch and pure cultures

    • Fermentation and Pasteurization

    • Germ theory of desease

    • Vaccination
The discovery of microbial effects
on organic and inorganic matter

 The Russian microbiologist
 Winograsky discovered that soil
 bacteria could oxidize iron, sulfur
 and ammonia to obtain energy,
 and also isolated nitrogen – fixing

 Beijerinck made fundamental
 contributions to microbial ecology.
 He isolated Azotobacter and
Alexander Fleming

                    Sir Alexander Fleming discovered
                    the antibiotic penicillin. He had
                    the insight to recognize the
                    significance of the inhibition of
                    bacterial growth in the vicinity of a
                    fungal contaminant when most
                    other scientists probably would
                    have     simply    discarded      the
                    contaminated plates.
1.5 Important events in the
       development of microbiology

1676    Leeuwenhoek discovers "animalcules"
Think and answer following questions:
1. How did Pasteur's famous experiment defeat the
   theory of spontaneous generation?
2. How can Koch's postulates prove cause and effect in a
3. Who was the first person to use solid culture media in
   microbiology? What advantages do solid media offer
   for the culture of microorganisms?
4. What is the enrichment culture technique and why was
   it a useful new method in microbiology?
5. When and how Alexander Fleming discovered
Reference books
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