Microbial World and You

Microbial World and You
Prologue 序 言

Chapter Objective:
1. How has Microbiology, as a subject,
developed so far
2. What may microbiology do for your
career And your life

What is microorganism
• Micro–
– Too small to be seen with the naked eye
• Microorganism (or microbe):
– Tiny creatures not seen with unaided eye
Microorganisms - Microbes - Germs
• Microbiology
–Bio-: life; -ology: study of

What is Life 生 命 是 什 么
• 5 Characteristics of Life 生 命 五 大 特 征
1. Cells 具 有 细 胞 形 态
2. Metabolism 新 陈 代 谢
3. Reproduction (growth) 繁 殖
4. Respond to stimuli from external
environment 对 外 界 刺 激 产 生 反 应
5. Evolve and adapt to the environment 进 化
并 适 应 环 境

Bacteria - what comes to mind
• Diseases: infections 传 染
• Food Spoilage
Facts: among all bacteria disease...
1% 4%
95%
Human disease
Plant disease
Non-pathogens

Microbes and Disease
• Origin & development of microbiology
• Napoleon in Russia
– Typhus 斑 疹 伤 寒 , tetanus 破 伤 风 , etc.
intimately connected
Warfare
Why
Infectious diseases
Poor sanitation, people movement,
malnutrition → outbreaks

“Dance of Death”

The Black Plague
黑 死 病 , 鼠 疫
Another recurrence of plague in
Naples in 1656

Historical Perspectives - 3 Phases of
Microbiology Development
1. Beginning of Microbiologly
2. Transition Period
3. Golden Age of Microbiologly

Phase 1: Beginning of Microbiology
• 1665 Robert Hooke
– “little boxes” – “cells”
– Cell Theory 细 胞 学 说
– Microscope: an important tool for
microbiology

Anton van
Leeuwenhoek
• first microbiologist
-1st person to
actually see living
microorganisms
Lens
Specimen
mount
Screw plate
Focusing screw
Elevating screw

Phase 2: Transition Period
• What life was like at that time
1. Spontaneous Generation 自 然 发 生 说
– Maggots 蛆 -nonliving things, flies-manure
2. Biogenesis 生 物 发 生 说 - Germ Theory
of Disease
– Life from pre-existing Life

Lister Introduces Antisepsis 消 毒
1865, Joseph Lister: antisepsis with phenol 石 碳 酸

Essence of scientific method - Logic reasoning
1. Build on established
scientific fact
2. Formulate a hypothesis
3. Test it with
an experiment

Biology: The Science of Life
Observation →Hypothesis →Conclusion
• Scientific
1. Principles: underlie all inquiry
2. Method: basis for scientific inquiry
3. Theories: thoroughly tested

Francesco Redi: disprove Spontaneous
Generation
• 1668: Fly - meat experiment
– Maggots only appeared in the open jar

Phase 3: Golden age of microbiology
• Father of modern microbiology: Louis
Pasteur
• Father of bacteriology: Robert Koch
• → Modern microbiology

Louis Pasteur - “swan-necked flasks”
1850‘s: spontaneous generation controversy

1860 年 巴 斯 德 用 实 验 证 明 肉 汤 不 能 生 出 微 生 物

Pasteur’s Credits
1. Cultivation 培 养 of Viruses & Bacteria
– Cultivation in an appropriate, sterile medium →
basis of microbiology
2. Vaccines 疫 苗
– Attenuation 减 毒 : cholera 霍 乱 , rabies 狂 犬 病
3. Aseptic Technique 无 菌 操 作
4. Fermentation - exclude oxygen from wine
– Aerobic vs. Anaerobic
5. Pasteurization 巴 斯 德 消 毒

“There are science and the
applications of science, separate yet
bound together as the fruit of the
tree.”
- Louis Pasteur, describing how pure
and practical science are related

A Case of "Microbes Revenge"
• During his investigation on bacteria,
two of Pasteur's daughters and his
father died of Typhoid fever 伤 寒

Robert Koch – Microbial Etiology
微 生 物 病 原 学
• 1876: 1st proved bacteria caused disease
• Established “scientific rules”
– Show a cause-effect relationship between a
microbe and a disease: anthrax
– Koch‘s Postulates
• 1905: Nobel Prize in Physiology or
Medicine

Koch‘s Postulates 科 赫 原 则
1. Isolate the suspected agent from a
disease victim;
2. Grow the agent in pure culture;
3. Infect a healthy host and show that
the organism produces the classical
clinical disease;
4. Isolate the "same" organism from
the new victim.

Koch: Etiology of 3 diseases
1. Cholera 霍 乱 (fecal-oral disease)
– Vibrio cholerae
2. Anthrax 炭 疽 (sheep and cattle)
– Bacillus anthrasis
• Tuberculosis 结 核 病 (pulmonary 肺 部 的
infection)
– Mycobacterium tuberculosis
Fannie Eilshemius: 1st to use Agar to solidify
culture media–Woman in Microbiology

Exceptions to Koch‘s Postulates
1. Some organisms never been grown in
pure culture on artificial media
– Treponema pallidum 梅 毒 螺 旋 体 –Syphilis 梅 毒
– Mycobacterium lepra 麻 风 分 支 杆 菌 –Leprosy
2. Morally unacceptable on “human
guinea pig”
– Ex: Does HIV cause AID’s

Treponema pallidum 苍 白 梅 毒 螺 旋 体 - Syphilis 梅 毒
Mycobacterium lepra 麻 风 分 枝 杆 菌 –Leprosy 麻 风

E. Jenner: Immue to smallpox 天 花
• Ancient China → India
• "if you want to marry a woman who will never
be scarred by the 'POX', marry a milkmaid"

Critical thinking questions:
1. What do you think of Jenner using a
child to test his theory on How about
today
2. What shall we do with the remaining
smallpox virus Your vote
3. Botulism 肉 毒 杆 菌 毒 素 for cosmetology
美 容

Semmelweis: Defender of Motherhood

Conquest of Yellow Fever by Major Walter Reed

Achievement by the Golden Age of
Microbiology
• By 1930’s
– Grow most agents
– Purify agents
– Observe agents (Light and TEM 透 射 电 镜 )
– Vaccines (prevent some diseases)
• Bacteria, Viruses, Parasites, Molds

Highlights in the History of Microbiology
1674 Leuwenhoek discovers microorganisms
1796 Jenner creates a vaccine for smallpox
1847 Semmelweiss establishes the causes of childbed fever
1859 Pasteur disproves spontaneous generation of microorganisms
1865 Lister introduces antiseptic techniques
1876 Koch proves specific microorganisms cause specific diseases
1881 Koch uses agar to obtain a pure culture
1892 Iwanowski discovers viruses
1894 Ehrlich articulates the principle of selective toxicity
1929 Fleming discovers penicillin
1977 Carl Woese discovers the archaea

Partial Nobel Prizes Awarded for Research in Microbiology
Date Scientist Research
1901 E. Von Behring (GR) Diphtheria antitoxin 白 喉 抗 毒 素
1902 R. Ross (GB) Cause and transmission of malaria 疟 疾
1905 R. Koch (GR) Tuberculosis research 结 核 病
1908 P. Ehrlich, E. Metchnikoff Work on immunity
1945 A.Fleming, Chain (GB), Florey (AU) Discovery of penicillin and its therapeutic value
1962 F. Crick (GB), J. Watson (US) Discoveries concerning the structure of DNA
1980 B. Benacerraf, G. Snell (US),
J. Dausset (F), P. Berg (US),
W.Gilbert (US)&F.Sanger (GB)
1984 C. Milstein (GB) G. Kohler (GR)
N.K. Jerne (D)
1989 J.M. Bishop; H.E. Varmus (US)
S. Altman; T.R. Cech (US)
1993 K. B. Mullis (US)
M. Smith (US)
R.J. Sharp (US)
Discovery of histocompatibility antigenes
Development of rDNA technology ,
Sequencing techniques (Chemistry Prize)
Technique for formation of monoclonal antibodies 单
克 隆 抗 体
Discovery of oncogenes 致 癌 基 因 ,
Discovery of catalytic RNA
Invention of the polymerase chain reaction
Development of site-directed mutagenesis 定 向 突 变
Discovery of split genes 断 裂 基 因
1997 S. Prusiner (US) Discovery of prions 朊 病 毒

Microbiology Today
• Chemotherapy 化 学 疗 法
– Synthetic drugs: sulfas
– Antibiotics
• Immunology, Virology: 1892
• Genetic Engineering: rDNA technology
• Future: Microbiology in post-genome
period
1. Antibiotics resistance
2. Evolution of new viruses: HIV
3. Food-born disease
4. Bioremediation

Recent outbreaks of epidemics
• Ebola virus 埃 博 拉 病 毒 ,1976, mortality50-90%
• Mad Cow Disease 疯 牛 病 : Europe, US,
• Monkey pox 猴 痘 : 2003, Mortality 10%
• SARS: spring 2003
• Avian Influenza 禽 流 感 : 2004
• Plague 青 海 鼠 疫 , Oct 2004, mortality50-100%
• Encephalitis B 乙 型 脑 炎 , Jan 2005
• More ……

Where will microbiology go

Five Characteristics of Microbes
1. Small size but big area
体 积 小 , 面 积 大
2. Strong absorption and fast metabolism
吸 收 多 , 转 化 快
3. Fast growth and rapid reproduction
生 长 旺 , 繁 殖 快
4. Powerful adaptations and easy mutation
适 应 强 , 易 变 异
5. Wide distribution and variable classes
分 布 广 , 种 类 多

Figure 1. Relative Size of Microbes.

Category of Microorganisms 微 生 物 分 类
• 3 categories and 10 groups :
1. Prokaryotes 原 核 生 物 : include eubacteria&archaea
1 Bacteria 细 菌
2 Actinomycetes 放 线 菌
3 Cyanobacteria 蓝 细 菌 (blue algae, 蓝 藻 )
4 Mycoplasma 支 原 体
5 Rickettsia 立 克 次 体
6 Chlamydia 衣 原 体
2. Eukaryotes 真 核 生 物
1
2
3
Fungi 真 菌
Macro algae 显 微 藻 类 (not included in our content)
Protozoa 原 生 动 物 (not included in our content)
3. Acellular microorganisms 非 细 胞 微 生 物
• Viruses 病 毒 : Neither prokaryotes nor eukaryotes

Organisms & its branch study of
Microbiology
1. Bacteria 细 菌
2. Protozoans 原 生 动 物
3. Algae 藻
4. Parasites 寄 生 物
5. Yeasts & Molds 酵 母 , 霉 菌
– Fungi 真 菌
6. Viruses
• Bacteriology
• Protozoology
• Phycology
• Parasitology
• Mycology 真 菌 学
• Virology

Microbes Benefit Humans
1. Primary decomposers
– Recycle nutrients back into environment
(sewage 污 水 treatment plants)
2. Produce various food products
– cheese, pickles, green olives
– yogurt, soy sauce, vinegar, bread
– Beer, wine

3. Microbes are used to make
Antibiotics 抗 菌 素 类
– Mold - Penicillium notatum 点 青 霉
– 1928 Alexander Fleming

4. Bacteria synthesize our
essential chemicals
• Example: E. coli
– B vitamins - for metabolism
– Vitamin K - blood clotting

5. Biochemistry and Metabolism
• Very simple structure
• Rapid rate of reproduction
• Provides “instant” data

6. Microbial Antagonism 拮 抗 作 用
• Our normal microbial flora prevents
potential pathogens from gaining
access to our body

7. Insect Pest Control
• Using bacteria to control the growth
of insects
• Bacillus thuringeinsis
– Caterpillars
– Bollworms 棉 子 虫 ; 螟 蛉
– Corn borers

8. Bioremediation
• Using microbes to clean up pollutants
and toxic wastes
• Exxon Valdez - 1989
• 2 Genera
– Pseudomonas sp.
– Bacillus sp.

9. Recombinant DNA Technology -
Gene Therapy, Genetic Engineering
• Produce enzymes and proteins
– Insulin 胰 岛 素
– Human Growth Hormone
– Interferon 干 扰 素

10. Microbes form the basis of
the food chain
• Marine & fresh water microorganisms

Microbes do benefit us, but they are
also capable of causing many diseases
• Pneumonia 肺 炎 Whooping Cough 百 日 咳
• Botulism Typhoid Fever 伤 寒 Measles
• Cholera 霍 乱 Scarlet Fever 猩 红 热
• Syphilis Gonorrhea 淋 病 Tetanus 破 伤 风
• Chlamydia 衣 原 体 Tuberculosis 结 核
• Meningitis 脑 膜 炎 Herpes 1&2 疱 疹
• Strep Throat Lyme Disease AIDS
• Black Plague 鼠 疫 Diarrhea 腹 泻

Impact of microorganism on human affairs
Agriculture
Food
Disease
Microbiology
Energy/environment
Biotechnology

Careers as a Microbiologist
B.A., B.S.
Research associate
Food, industrial, or environmental microbiologist, quality
assurance technologist
Clinical or veterinary microbiologists
M.A., M.S.
Supervisor or laboratory manager, instructor
Ph.D., M.D.
Scientist, University or college professor, research director,
consultant, infectious disease specialist

SUMMARY
1. What is microorganisms and their major
categories
2. The individuals, with discoveries & time
frame, covered in microbiology history.
3. The importance of microbiology and their
relationship to other biology branches
4. 5 major characteristics of microorganism

Discussion
• In 1911, the Polish chemist Casimir Funk
isolated an active substance from rice husks
and proposed that it prevents beriberi, a
disease of the muscular and nervous
systems. “Nonsense,” he was told, “Spend
your time more profitably – look for a
microorganism!” Today we know that Funk
was correct: Beriberi 脚 气 病 is a nutritional
disease caused by a vitamin deficiency. But
at that time, the scientific community
scoffed at his idea. Why do you think that
happen

Question