微生物大题-英文

1、1. Pass内毒素外毒素的主要区别？ExotoxinEndotoxinExcreted by living cells, mainly by G+ bacteriaIntegral part of G- bacteria cell wall, liberated upon bacteria disintegrationpolypeptideLPS, main toxic part- lipid AHeat-unstableHeat-stable, 160, 24hr destroyStrong antigenicity, induce body to produce antitoxin, e

2、xotoxintoxoidWeak antigenicity, cant convert into toxiodHighly toxicWeakly toxicHigh selection for tissues: neurotoxin, cytotoxin, enterotoxinNon-specific, all endotoxins produce the same symptomsfever; WBC reaction; endotoxemia and shock; DIC.Structure: A subunit-B subunit. A subunit: toxic part; B

3、 subunit: non-toxic, bind receptor of sensitive cellLPS: lipid A, core polysaccharide, specific polysaccharide(O antigen)2.Pass mechanism of cholera pathogenic:霍乱1)pathogenic factor: invasiveness: flagellum, pili; cholera enterotoxin: contain A and B subunits. A subunit-Ag weak, active unit, enters

4、the cell, stimulates adenylate cyclase-cAMP-secreting effect-severe diarrhea; B subunit-Ag high, bound unit, attaches to receptor on epithelial cells of small intestine.2)mechanism: Organisms-oral route(contaminated water, food)-stomach-attach to the small intestine epithelialcells(non-penetration)-

5、multiplication-cholera enterotoxin-adenylate cyclase-cAMP concentration-secreting effect-severe diarrhea(rice-water stools)-rapid dehydration and hypovolaemic shock低血容量休克-die in 1224 hours.Ps. Transmission: polluted water and food, by mouth3.Pass Clostridium tetani- pathogenesis破伤风1)condition:Wound+

6、sporeDeep, narrow and contaminated by soil;Necrotic坏死的 tissue;Companied with aerobe or facultative anaerobe infection.2)pathogenic substance:Tetanospasmin破伤风痉挛毒素- neurotoxin: proteinTetanolysin破伤风溶血毒素3)mechanism:根据课件整理一下Spores-vegetative bacteria细菌繁殖体-grow locally-tetanospasmin-( along nerve fiber/

7、blood)-anterior horn cells of spinal cord, binds to ganglioside receptor神经节苷酯受体 and blocks release of inhibitory mediators-cause convulsive痉挛的 contraction of voluntary muscle.4.Pass dsDNA病毒的复制周期答：复制周期依次包括：吸附。穿入。脱壳。生物合成。组装、成熟和释放。Replication cycle: adsorption-penetration-uncoating-biomolecular synthes

8、is-assembly-maturation-release5.Pass HIV致病机制：Pathogenesis: Gp120 of HIV select CD4 molecule of T4 cells;Viruses multiply in T4 cells;Cell-mediated immunodeficiency;Opportunistic infections and tumor occurs;DeathHIV损伤CD4 T细胞的机制：导致CD4 T细胞融合，最终导致细胞的溶解； CTL对CD4 T细胞的直接杀伤作用，抗体介导的ADCC作用，NK细胞的杀伤作用；诱导CD4 T细胞

9、细胞凋亡；HIV复制产生大量未整合的病毒DNA，抑制细胞正常的生物合成；HIV可作为超抗原激活大量CD4 T细胞。6，gp41与细胞膜上MHC二类分子有同源性homology，诱导产生具有交叉反应的自身抗体，致使T细胞损伤。 Destruction of T4 cells is achieved by: Viral replicationSyncytium合胞体 formation via membrane gp120 binding to cell CD4 antigenCytotoxic T cell lysis of infected cellsCytotoxic T cell

10、 lysis of T4 cells carrying gp120 released from infected cells  Antibody-dependent cell cytotoxicity. Induce appoptosis.8.Pass functions of special cell structure of bacteria:1) capsule: slime layer outside the cell wall, composed of polysaccharide or polypeptide.Functions: anti-phagocytos

11、is; adherence; protect from lesions by harmful substances; anti-dry; antigenicity2) flagellum: originate from cell membraneFunctions: motility; antigenicity(H antigen); pathogenicity: some bacteria3) pilus: Common pilus: adhere to surface of cell, associated with pathogenicitySex pilus: transfer gen

12、etic material (DNA) during bacteria conjugation4) spore: resting form, forming: inadequate nutritionFunction: highly resistant to heat, chemicals, dry9. Pass streptococcus 致病物质及主要疾病： 1) invasivenessAdhesion: LTA(脂磷壁酸)、M protein-adhere to sensitive cell2) enzyme:Hyaluronidase: split hyaluronic acidba

13、cteria spreadStreptokinase: lyse fibrin, prevent plasma clottingbacteria spreadStreptodornase(链道酶): resolve DNAbacteria spread3)toxin-exotoxinStreptolysin(hemolysin)链球菌溶血素: destroy blood cellsPyrogenic exotoxin致热外毒素：superantigen, cause scarlet fever猩红热Disease:Pyogenic infection(化脓性感染)Toxin disease:

14、scarlet feverNon-pyogenic infection(1) rheumatic fever(2) acute glomerulonephritis10.Pass what is plasmid? Its features.plasmid is the extrachromosomal genetic elements which is small circular double-stranded DNA molecules. They are capable of self-replication and contain genes that determine many p

15、roperties. Features:1) extra-chromosomal genetic material circle2) ds DNA3) dispensible(非必需的)4) replicated independently5) carry genetic information6) control a wide range of function to bacteriafactor Fcontrol sex pilifactor Rcontrol drug resistance7) transferred between bacteria11.Pass what is lat

16、ent infection. Take HSV as example.Latent infection: virus is usually not detectable but patient may have periodic out-breaks of disease. In this infection, the acute disease is followed by an asymptomatic period during which the virus remains in a latent state.12.Pass distributions and functions of

17、 normal flora1)distributions: skin, oral cavity, intestinal tract, vagina2)functions:antagonism: biological barriernutrient synthesize: VB, VKimmune: enhance and develop the maturation of immune systemanti-caducity(抗衰老)anti-tumor13.Pass 结核分枝杆菌的传播途径和致病因子：1)route: by respiratory tract, digestive tract

18、 or damaged skin.2)pathogenic substances:lipid：A.cord factor: associated with virulence; inhibit migration of leukocyte to form chronic granuloma; bind to mitochondrial membranes, influence the cell respiration B. Phosphatide磷脂: stimulate monocytes proliferation-form tubercleC. Wax D: act as an adju

19、vant, cause DTHD. Sulfatides硫酸脑苷脂: inhibit the fusion of phagosome and lysosomeprotein tuberculin结核菌素 Tuberculin+waxD-DTH Ag-Ab(no protection)polysaccharide :combine with waxD- cell filtrationmycobactin(分枝菌生长素)致病机制加上这句话：No endotoxin, exotoxin, no capsule, and no invasiveness enzyme致病机制：No endotoxin,

20、 exotoxin, no capsule, and no invasiveness enzyme.加上上面的致病物质Primary tuberculosis: organism-respiratory tract-pulmonary alveoli-lesion-lymph nodes-swelling-fibrosis-natural curePost primary tuberculosis: organism-infection again-inflammation-necrosis坏死-tubercle结节-fibrosis纤维化14.Pass HBV基因组及其编码的蛋白。传染源，传

21、播途径长链为负链，固定长度；短链为正链，长度可变负链negative strand DNA有四个区：S、C、P、XS：HBsAg, PreS1Ag, PreS2AgC: HBeAg, HBcAgP: DNA polymerase, reverse transcriptase, RNaseHX: HBx(x protein)-associated with tumorSource of infection: patients, HBsAg carrierTransmission way : blood or blood products; sexual contact; vertical tra

22、nsmission(birth, breast-feeding)防治原则：prevention: vaccine: recombinant HBsAg vaccines;serum derived vaccine Treatment: interferon; lamividine etcPass乙肝五项，微生物检测的成分及意义HBsAg, anti-HBsAg, anti-HBcAg, HBeAg, anti-HBeAgHBsAg: a patient infected with HBV; acute infection recently; a carrierAnti-HBsAg: prote

23、ctive or recoveryAnti-HBcAg: viral multiplication; active infection;infectiousHBeAg:viral multiplication; active infection; infectiousAnti-HBeAg:multiplication and active infection are reduced; has less infectious附：HBc一般不易游离于血循环中，故不易从患者血清中查出。但HBcAg可在肝细胞膜表面表达，抗原很强，可诱导宿主CTL细胞反应，并能刺激机体产生非保护性抗体HBc抗体。HBc

24、AgZ存在于HBV核衣壳表面，或位于感染的肝细胞中，血中不易检测到，故不用于HBV标志物的常规检查。15.Pass tuberculin test: using OT or PPD to detect whether it can cause DTH of skin, in order to judge if body has the immunity to tubercle bacillus. Principle: DTH Method: PPD-injection-4872h later-induration硬结, inflamed红肿 Results: <5mm, no TB in

25、fection; Early stage of primary infection; Severe patient of TB Cell immune function decrease(virus infection, use of immunosuppressive drug)5mm<<15mm, hypersensitivie to TB; immunity>15m, active infection perhapsApplication: basis of BCG inoculation, detect immunity effect Diagnosis of you

26、ng children tuberculosis Epidemiological investigation Cellular immunity test of patients with tumor16.Pass 支原体与细菌L型的比较：MycoplasmaL-bacteriacolonyFried-egg(bigger)Fried-eggMorphologyMany(bigger)manyCell wallnoNo or deletionReason for no cell wallgeneticPhenotype variation, can recoverCell membrane1/

27、3 is cholesterolNo cholesterolLiquid cultureLow milkymilky17.Pass衣原体chlamydia的共同特征：圆形或椭圆形，革兰阴性同时含有DNA和RNA严格真核细胞内寄生具有类似格兰阴性菌的细胞壁必须由宿主细胞提供所有代谢活动的能量来源独特的life cycle: elementary body, initial body18.Pass 比较原体和始体：Elementary body: infection form, has cell wall, extracellular parasiteInitial body: replicati

28、on form, has no cell wall, intracellular parasite19. Characteristics of IFNs 1. anti-viral functions: 1) act indirectly on virus 2) broad-spectrum antiviral activity 3) host species specific and cellular selective: inhibit viral replication only in the species in which it was produced 4) act in the

29、early stage of viral infection2. anti-tumor 3. immune regulationAntiviral mechanisms:IFN-combine with IFN receptor on cell surface-AVP gene activated-AVP mRNA transcribed-AVP synthesis2,5-A synthetase: degrade mRNA of virusProtein kinase: inhibit protein synthesis of virus21. HA功能hemagglutinin（血凝素）：

30、流感病毒2units: HA1and HA2 * agglutinate human and some animal RBC * be related to the adsorption of viruses (receptor : neuraminic acid神经氨酸，即唾液酸受体 ) * antigenicity: show great variability Abs to the HA are protective, neutralize viral infectivity. 22.Pass Effects of viral infection on cells 1）. cytocid

31、al infection (naked viruses) virus which infect and replicate within cells causing the cells to lyse when the progeny virions are releaed. mainly found in naked viruses. CPE (cytopathic effect )细胞病变效应2）. steady state infection (enveloped viruses) viruses are produced from the infected cells but the

32、cells are not killed by the process. Lead to: integration of viral Ag in host cell membrane, so the immune system may recognize it as foreign; cell fusion.3）. cell apoptosis virus or viral protein induce the process.4）. viral genome integration integration: integration of the viral genome into cellu

33、lar DNA5）. cell hyperplasia增生 and transformation morphous change loss of contact inhibition immortalization 不朽永生 new antigen6）. inclusion bodyround, oval or irregular-shaped bodies occurring in the cytoplasm or nucleus of virus-infected cells, can be seen under the microscope.23.Pass the mechanism o

34、f bacterial variation.Variation examples:Shape and structure variation;Colony variation:Virulence variation;Resistance variation.(1)Mutation: a stable heritable change of bacterial gene; spontaneous or induced1)point mutation: base replacements;base deletion lost;base insertion 2)multiple mutation:

35、rearrangement(2)genetic transfer:Genetic substance of bacteria is transfered to another bacteria.1)transformation: recipient bacteria directly takes up exogenous DNA of donor bacteria. Competence: bacterial state- at which bacteria can take up DNA from environment in log phase.2)transduction: Gene t

36、ransfer from a donor to a recipient by way of a bacteriophage generalized transduction: any fragment of donor bacteria is transferredspecialized transduction: the fragment near attachment is transferred 3)Conjugation: bacterial DNA is transferred from donor bacteria to recipient bacteria by sex pilu

37、s4)Lysogenic conversion:The presence of prophage DNA constitutes a genetic alteration to the host cell 5)Protoplast fusion24.Pass The Function of Cell Wall 1) protection 2) keep the constant shape 3) antigenicity 4) exchange material25.细菌的致病机制：(1)virulence1) invasiveness:Surface structure:Adhesin: p

38、ili adhesin; no-pili adhesin;Capsule and microcapsule;Flagella;Bacterial biofilm.invasive substance:Invasin;Invasive enzymeimmune escape:Anti-phagocytosis;Produce IgA proteinase;Antigenic shift;Interfere complement activity.2) toxin:exotoxin; endotoxin.(2)infective sites, portal or route(3)infective

39、 numbers(4)the immunity of host26. the mechanism of Drug Resistance.细菌抗药机制(1) genetic mechanism:1) intrinsic resistance: bacteria absence of the target for the action of the drug.2) acquired resistance: a result of genetic change and subsequent selection by antimicrobial drugs.chromosomal mutationac

40、quisition of plasmid carrying a resistance geneacquisition of transposable element carrying a resistance gene.(2) biochemical mechanism:modified enzymes钝化酶. Bacteria produce, inactivate the drugs.bacteria develop an altered structural target for the antibacterial drug.bacteria decrease their permeab

41、ility, efflux pump system主动外排.27.Pass 几种病毒疫苗：Measles-mumps-rubella vaccine, MMRPoliovirusoralRabies virusAll live attenuated vaccine.28.Pass virulence factors of G+ bacteria:(1) structural substance of bacterial: adhesion: LTA脂磷壁酸, ect.(2) capsule and invasive enzyme(3) exotoxin29.Pass pathogenicity

42、 of S. aureus金葡菌的致病1. Pathogenic Factors1). Invasiveness (1) Surface structures SPA capsule Adherence & anti-phagocytosis peptidoglycan teichoic acid (2) Invasive Enzyme Coagulase a) to inhibit the phagocytosis of phagocytes and damage of bactericide substances in serum by coating the organisms

43、with fibrin; b) to prevent bacteria spreadingincluding: free coagulase; bound coagulase.2). Toxin - exotoxin(1) . Staphylolysin: a、b、g、dcytotoxic effects on phagocytic and tissue cells (2).Leukocidin: cytotoxic effects on Killing PMN & MF(3).Enterotoxin:Cause a food poisoning characterized by se

44、vere vomiting and diarrhea;(4). Exfoliatin剥脱素: Cause blistering of skin (5). Toxic shock syndrome toxin-1 (TSST-1): induce TSS2. diseases1) Invasive diseases - pyogenic infection  (1) local infection: skin infection: folliculitis; boil; carbuncle; impetigo (thick pus; limited local area) (2) organ infection: pneumonia; meningitis; endocarditis (3) Systemic infection: septicemia; pyemia2) toxin diseases - exotoxin (1) Food poisoning (enterotoxin)  (2) SSSS (staphylococcal scalded skin syndrome)  (3) TSS (Toxic shock syndrome) 30.Pass pathogenicity of Streptococcus