medical microbiology.doc
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1、Medical MicrobiologyChapter 1 IntroductionI. Microbes 1. Definition (microorganism): are the little and simple organisms with rapid growth rates.2. Classification: 1) Noncellular type Such as: virusesGeneral Characteristics of Viruses :1. Smallest: 20 300 nm, most were too small to be seen with the
2、light microscope , filtrable.2. Simplest: non-cellular entity, contain DNA or RNA and protein.3. Obligate intracellular parasites (专性细胞内寄生): growing only within the living cells. 4. Self-replication (自我复制): Once it has invaded a cell it is able to direct the host cell machinery to synthesize new int
3、act infectious virus particles (virions).Definition of a virus:2) Prokaryotic type No nuclear membrane or mitotic apparatus, only nuclear region can be seen, which composed of DNA.No separate internal membrane bound organelles .Such as: Archaebacterium(古细菌): Eubacterium(真细菌): Bacterium Mycoplusma Ch
4、lamydia Riclcettsia Spirochetes Actinomycetes Cynaobacterium(蓝细菌):no pathogenesis to human3) Eukaryotic type intracellular membrane enclosed organelles,nucleus : two membrane layers Endoplasmic Reticulum (ER): rough ER ;Smooth ER MitochondriaSuch as Fungi : hyphae and yeast3. Distribution of Microor
5、ganisms:1) In environments.2) In human organismsII Microbiology and Virology1. research objective : Pathogenic Microbes 1)biological properties 2)pathogenesis and immune response 3) Diagnosis 4)therapy and protection Microbiology: Virology:is the study of viruses, complexes of nucleic acids and prot
6、eins that have the capacity for replication in animal, plant and bacterial cells.2. HistoryLeeuwenhock: invent Microscope in 1674 . Pasteur : pasteurization , Vaccine Koch : solid medium, purify bacteria Pathogenic microbe criterion Lister : disinfection aseptic technique Iwanovsky : virus.3. Modern
7、 Microbiology 1) Most bacteria were controled by antibiotics. Drug-resistant strains resistence plasmid. 2) Normal floraopportunistic pathogens (flora disequilibrium super-infection ) Hospital acquired infections. New bacteria : Helicobacter pylorichronic gastritis.3) Viral researches have made prog
8、ress. New presented viruses: AIDSNew diagnostic techniques . ELISA; PCR( polymerase chain reaction.)Viral infection associated with tumors:mechanisms of Viral disease; anti-infection immunology and develop vaccines:Research tools of molecular biology:anti-virus drugs:4) New type vaccine .Microbial g
9、enomic program, MGP .Basic Principles of MicrobiologyChapter 2 Basic Properties of microbesSection I BacteriaI . Size and Shape of bacteria(I ) Size of bacteria Measure unit: um(micrometer): Coccus 1 um bacillus 23um(II) Shape of bacteria 1. coccus (cocci)1) diplococcus : in pairs 2) streptococcus:
10、long chain 3) tetrad and sarcina: 4) staphylococcus: irregular cluster2. bacillus (bacilli): rod3. Spirilla bacterium 1)vihrio v. cholera2)Spirillum Helicobacter H. pyloriII. Basic Bacterial Structure cell wall Basic structure cell membrane, mesosomeCytoplasm: ribosome, plasmid, cytoplasmic granules
11、; nucletid (I)cell wall1. function :1)protection 2) keep the constant shape . 3)antigenicity .4) exchange material2. structure and chemical composition: peptidoglycan(mucopeptide)1)polysaccharide backbone: N-acetyl glucosamine link N-acetyl muramic acid with 1.4 glucosidic bond2)tetrapeptide side ch
12、ain: link muramic acid. ala glu lys ala 3)pentaptide bridge: G+ : Lglycine; G : diaminopimelic acid 3. Special components of Gram-positive cell wall (1) eichoic acids : wall teichoic acid and membrane teichoic acid functions :1) bind Mg2+(magnesium) upply of this ion to the cell2) provide the cell w
13、ith its consistency3) adhesion -pathogenicity 4) antigenicity(2) polysaccharidesmay contain a variety of sugars. 4. Special components of Gram-Negative cell wall .(1) peptidoglycan(2) Outer membrane : exchange receptor(sex pili phaqe)1) Lipoprotein are firmly but non covalently attached to the pepti
14、do-glycan and out membrane 2) lipopolysaccharide, LPS a complex and unique glycolipid consisting of three distinct but covalently linked regions: a) lipid A: glucosamine disaccharide units connected by pyrophosphate bridge . endotoxin , non-genus specificb) core polysaccharidec) specific polysacchar
15、ide “O” Ag(II)Cell membranemesosome : invaginated vesicular membrane,to increase membrane area such as chondriosome(线粒体) and spindle.Function as 1) spindle-like(类纺锤体):cell division 2) chondroid(类线粒体):(III)Cytoplasmplasmid:extra-chromosomal genetic material, circle double streands DNA, to replicate i
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