1. 医学微生物学概论 Understanding the medical microbiology Dr. Jing Qian Zhejiang University School of Medicine April 09, 2014 现代医学导论 2012 级食品安全与营养专业求是科学班

2. Definitions –Microorganisms(Microbes) 微生物 –Microbiology 微生物学 –Medical Microbiology 医学微生物学

3. The word “microbe” comes from the Greek words mikros, meaning small, and bios, meaning life. So microorganisms/microbes are small living things that are too small to be seen with the unaided eye. Microorganisms were probably the first organisms to appear on the earth. However, these organisms were not seen until about 3 centuries ago when lenses powerful enough to make them visible were made. Viruses, bacteria, fungi, protozoa and some algae are all in this category. Microorganisms/Microbes

4. The distribution of microorganisms is universal in nature including air, soil, water, animals, human body. Distribution Distribution

5. There is a close relationship between microorganisms and human beings. Beneficial activities: Most microbes are of benefit to human beings, some are necessary. eg. nitrogen, carbon cycles, etc. Harmful activities: Only a small portion of microbes cause diseases and are poisonous to human, and these pathogenic microbes are really that concern us in the study of medicine. Harmful activities: Only a small portion of microbes cause diseases and are poisonous to human, and these pathogenic microbes are really that concern us in the study of medicine. Relationship with human beings

6. Microbes in nitrogen cycle

7. Microbes in carbon cycle

9. Background knowledge: Cell is the fundamental unit of all living things to carry out metabolic processes that transform energy and materials for growth and propagation (multiplication). Organizational structure Organizational structure There are two fundamental types of cells: Prokaryotes and Eukaryotes with the major difference in whether or not the cell have membrane bound organelles and nucleus.There are two fundamental types of cells: Prokaryotes and Eukaryotes with the major difference in whether or not the cell have membrane bound organelles and nucleus.

10. The prokaryotic cell, in contrast to the eukaryotic cell, has no nuclear membranes, mitochondria, endoplasmic reticulum, Golgi body, phagosomes and lysosomes. Differences between prokaryotes/eukaryotes Prokaryotes generally possess only a single circular chromosome. Since there is no nuclear membrane, the chromosome is bound to a specific site on the cell membrane - the mesosome. Prokaryotic ribosomes are 70S (S means Svedberg unit, a measure of size for centrifugation), whereas eukaryotic ribosomes are larger (80S). Prokaryotic ribosomal subunits are 30S and 50S (eukaryotic are larger). The 30S ribosome has 16S RNA, while the 50S ribosome contains 23S and 5S RNA.

11. According to organizational structure, microbes can be divided into three types: Prokaryotes (Eubacteria and Archaebacteria) Eukaryotes (fungi, Protozoa, algae) Acellular entities (viruses) Classification of microbes Classification of microbes

12. Eubacteria are "True" bacteria which include Bacteria, Chlamydiae, Mycoplasmas, Richettiae, Spirochetes, and Actinomycetes. Some of them cause human diseases. Members of the Archaebacteria are often found in extreme environments (methane-containing, high salt or hot temperature) environments. They are not human pathogens and will not be discussed further. Eubacteria and Archaebacteria Eubacteria and Archaebacteria Eubacteria and Archaebacteria are the two major types of prokaryotes. They appear similar morphologically but have major biochemical differences.Eubacteria and Archaebacteria are the two major types of prokaryotes. They appear similar morphologically but have major biochemical differences.

13. Viruses Viruses Viruses are not living organisms because they do not contain all the enzymes required for their replication and possess the biologic equipment necessary for the production of metabolic energy. Viruses are non-cellular microbes. They are obligate parasites totally dependent on their host for replication. Morphologically, viruses are very small particles and have no basic cell structure. A simplest virus consists of one core and one protein coat (capsid). The core composed with a nucleic acid molecule, either DNA or RNA.

14. Fungi is a kind of eukaryotic cells. So they have various organelles, for examples, nuclear membranes, mitochondria, endoplasmic reticulum, Golgi body, phagosomes and lysosomes. Fungi Fungi There are more than 100, 000 species of fungi, but most of them are beneficial to humankind. They reside in nature and are essential in breaking down and recycling organic matters. Only a few of fungi can cause human diseases.

15. Microbiology is the biology of microorganisms. Microbiology It has an impact on medicine, agriculture, food science, ecology, genetics, biochemistry, and other fields. It is a bioscience for the study of various characteristics or activities of microorganisms including microbial morphology, cytology, physiology, ecology, genetics, molecular biology and taxonomy. Branches of Microbiology are Medical Microbiology, Food Microbiology, Public health Microbiology, Industrial Microbiology and Agricultural Microbiology

16. Medical Microbiology The medical microbiology is the study of pathogenic microbes. It concerns the biological characteristics of microorganisms and their relationships with human hosts including: Pathogenicity and immunity Laboratory diagnosis Prevention and treatment etc.

17. Medical Microbiology Branches of medical microbiology include Medical Bacteriology (Six eubacterial categories: Bacteria, Chlamydiae, Mycoplasmas, Richettiae, Spirochetes and Actinomycetes), Medical virology, Medical Mycology. Medical Microbiology contains anti-infectious immunity in Immunology. In some countries, Parasitology is enclosed Microbiology Understanding and employing the principles of microbiology and the molecular mechanisms of pathogenesis enable the physicians and medical scientists to control an increasing number of infectious diseases.

18. history and current situation Medical Microbiology

19. Infectious Diseases in History Tuberculosis Plague Smallpox Syphilis Influenza 3700 BC

20. Smallpox Numerous epidemics in Europe, Asia –Plague of Athens 430 BC –Antonia Plague of Rome 165-180 –India c. 400 Introduced to the Americas in 1520 by Cortés, killing 25% of Aztec population Spread to Incan population via roads North America in 1633, Plymouth, MA

21. Influenza Symptoms described by Hippocrates 412 BCE Ascribed to unfavorable astrological influences in Italy in the 15th Century First pandemic recorded in 1580 Term “influenza” used in English in 1743 Virus discovered by Medical Research Council in England in 1933

22. Influenza Pandemics 1918 Spanish flu 1957 Asian flu (H2N2) 1968 Hong Kong flu (H3N2) 1976 swine flu non- pandemic ? Avian flu (H5N1)

23. The numerous emerging and re-emerging infectious diseases such as AIDS, SARS, avian influenza, tuberculosis, viral hepatitis and so on. New challenge in medical microbiology

24. 30 years of emerging viral diseases 1986Bovine spongiform encephalopathy 1980 Hepatitis D1980 Human T-cell- Leukemia-Virus 1977 Hantaan-Virus 1976 Ebola fever 1985 HIV/AIDS 1981 HIV/AIDS 1989 Hepatitis C 1999 West Nile fever1994 New Variant of Creutzfeldt-Jakob-Syndroms 2003 SARS 2005 HPAI H5N1 2013 H7N9??

25. Emerging viral diseases: monkey pox virus A 7 year old girl from Zaire Monkeypox A member of the orthopox virus (next to: Variola) local outbreaks since 1990 It is a zoonosis in the Americas: prairie dogs

26. Kaposi-sarcoma origin: Human Herpesvirus type 8, HHV-8 = Kaposi-sarcoma-associated Herpesvirus, KSHV One of the leading diseases in (untreated) AIDS-patients Emerging viral diseases: Kaposi sarcoma

27. Influenza Hong Kong, 1997: death of 7.000 chicken in 3 farms  Crossing of species barrier of a new influenza strain (H5N1) from poultry to man  20 humans became infected. One third die. No human to human transmission.  Killing of 1,6 millions poultry to prevent spreading among poultry  Vietnam, Thailand, China, Laos, Korea, Japan, Kambodscha, Indonesien, 2004: reemergence of H5N1  Suspected human to human transmission Emerging viral diseases: Avian influenza virus

28. Development of Medical Microbiology Medical microbiology has developed from Experience phase, Experimental phase to Modern phase and is still keep developing. Some landmarks in each phase are:

31. Time line of Microbiology

34. Robert Koch Robert Koch : Koch’s Postulate Based on his experimental results, he raised a criteria, called as Koch’s Postulate, to establish the link between a particular microorganism and a particular disease: 1.The microorganisms must be present in every case of the disease but absent from healthy individuals. 2.The suspected microorganisms must be isolated and grown in pure culture. 3.The same disease must result when the isolated microorganism is inoculated into a healthy host. 4.The same microorganism must be isolated again from the diseased host.

35. Time line of Microbiology

37. Fleming and Florey (1945 nobel price)

39. Fei-Fan Tang 汤飞凡 （ 1897-1958 ） The first generation of virologist in China. He is the first scientist who was successful in isolating and cultivating chlamydia trachomatis in 1955. So far he is the only Chinese microbiologist who created a research field in microbiology.

40. Microbiology established a closer relationship with other disciplines during the 1940s because of its association with genetics and biochemistry. More recently, microbiology has been a major contributor to molecular biology and has been deeply involved in the elucidation of the genetic code; in studies on the mechanisms of DNA, ribonucleic acid (RNA), and protein synthesis; and in studies on the regulation of gene expression and the control of enzyme activity. In the 1970s new discoveries in microbiology led to the development of recombinant DNA technology and genetic engineering. Microbiology in nature science

44. The Nobel Prize in Physiology or Medicine 2008 was divided, one half awarded to Harald zur Hausen "for his discovery of human papilloma viruses causing cervical cancer", the other half jointly to Françoise Barré- Sinoussi and Luc Montagnier "for their discovery of human immunodeficiency virus".